Review Lpr the Global Information Hub for Lighting Technologies March/April 2018 | Issue 66

www.led-professional.com ISSN 1993-890X

Review LpR The Global Information Hub for Lighting Technologies March/April 2018 | Issue 66

Tech-Talks Bregenz: Fred Maxik Research: Lifetime Simulation & Optimization Technologies: LED Overvoltage, LED Drivers

Application: Thermal Management www.FutureLightingSolutions.com 10light+ 018 building 83 2018 LIGHTFAIR International Hall 4.1, Stand G10 18.-23.3.2018 Frankfurt am Main

FLS_CoverCorner_LED Pro_Combined.indd 1 2018-02-20 5:40 PM

CATEGORYEDITORIAL 4 An IP SnapShot Into Lighting

The lighting industry is facing enormous challenges and new stakeholders have started to enter this traditional market. With the advent of LED lighting and the whole world of smart, intelligent and connected lighting, the boundaries have also changed and even more uncertainties have arisen.

As we know, what we see and recognize on the market today was developed years ago in labs and at research institutes. Can we get a better understanding of the trends when screening the IP portfolios? The first thing we did was analyze the IPC class F21, which is assigned to lighting. Japanese companies have been the most active players in the last few years. Companies such as Panasonic, Toshiba, Koito, Sharp and Stanley are dominating the lighting IP field. Ocean’s King Lighting shows strong activities lately and together with Foxcoon they belong to the major IP players representing China. Philips has been showing strong, continuous IP activities since 2008. Of course this picture changes when we analyze certain areas in lighting. This gives us an overview of the complete lighting field of the IPC class F21.

A closer look into the numbers of patent families for certain technology fields or keywords of the past 5 years showed the following results for the main IPC class F21: LED (82,805), Connectivity (49,590), Optics (9,427), Production (7,182), Protection (7,053), Fluorescent (4,148), Safety (3,514), Thermal (3,182), Driver (2,579), Intelligence (2,530), Security (2,250), Laser (1,668), Quality (1,466), Phosphor (1,063), Modularity (1,001), OLED (566), Recycling (250), Internet (189), Software (141), and Sustainability (73).

The results show the importance of connected solid-state-lighting and the focus on producibility and quality aspects. On the other hand, there is room for more inventions in the filed of new light source technologies and sustainable lighting concepts.

The Light+Building fair in Frankfurt is soon and will be a good opportunity to compare the concrete industry developments with the picture of trends we have in mind. The LED professional team will be there as well and invite you to get in touch with us for a one-on-one meeting.

LpR issue #66 covers a lot of the above key topics including lifetime and protection issues and a very interesting interview with Fred Maxik.

Have a great read!

Yours Sincerely,

Siegfried Luger Publisher, LED professional

CONTENT OVERVIEW 6

COMMENTARY REGULARS 08 On Smart Luminaires 04 EDITORIAL by Prof. Tran Quoc Khanh, Technical University Darmstadt 08 COMMENTARY 10 COMPONENTS NEWS 26 APPLICATIONS NEWS 27 RESEARCH NEWS TECH-TALKS BREGENZ 32 CIE RESEARCH 34 Fred Maxik, Founder & CTO, Lighting Science Group compiled by Dr. Guenther Sejkora, LED professional 90 ABOUT | IMPRINT

RESEARCH HIGHLIGHTS Lifetime- and Economic Efficiency Simulation of LED Luminaires in Dymola/Modelica 40 50 Full-Color InGaN/AlGaN Nanowire by S. Haemmerle & T. Schmitt, University of Applied Sciences Vorarlberg LEDs for SSL and Displays 50 Full-Color InGaN/AlGaN Nanowire LEDs for SSL and Displays by M. R. Philip & Dr. H. P. Nguyen, by M. R. Philip & Dr. H. P. Nguyen, New Jersey Institute of Technology New Jersey Institute of Technology

EVENTS 56 Technology Is the Answer, But What Was the Question? by Arno Grabher-Meyer, LED professional

80 Method and Circuit to Maintain TECHNOLOGIES Constant Light Output for LED Luminaires A Near Infrared Enhanced LED Lighting Approach 62 by Prof.Dr.Eng. Stelian Matei, by Scott Zimmerman, Silas Electromagnetica

ENGINEERING 70 Electrical Over Stress - How to Prevent an LED Failing Earlier than Expected by Mauro Ceresa, Cree 80 Method and Circuit to Maintain Constant Light Output for LED Luminaires by Prof.Dr.Eng. Stelian Matei, Electromagnetica

ADVERTISING INDEX

FUTURE LIGHTING SOLUTIONS 1 LACKWERKE PETERS 19 SEOUL SEMICONDUCTOR 55 LUMILEDS 2 LACKWERKE PETERS 19 LUMINUS DEVICES 67 OSRAM 3 EPISTAR 21 FLS-PHILIPS 69 EVONIK 5 INTERLUMI PANAMA 23 FLS-NICHIA 73 LEDFRIEND 7 FUTURE LIGHTING SOLUTIONS 25 GUANGZHOU INT. LIGHTING EXHIBITION 75 LPS 9 ELECTROLUBE 27 CREE 79 OPHIR SPIRICON 11 INSTRUMENT SYSTEMS 28 A.A.G. STUCCHI 83 HELVAR 13 ADELS CONTACT 29 FULHAM 87 INFINEON 14 LEDIL 30 LIGHT FAIR INTERNATIONAL 89 WAGO 15 OSRAM 31 LPR 91 FISCHER ELEKTRONIK 17 TIL 49 WÜRTH 92 CREE 18 INSTRUMENT SYSTEMS 53

COMMENTARY ON SMART LUMINAIRES 8

ON SMART LUMINAIRES

In the time up to 2010, conventional on the current time of the day and

luminaires with low or high-pressure season. On the other hand, from the discharge lamps with a luminous efficacy lighting engineer’s point of view, the smart of about 80 lm/W were developed. luminaires of the future should change The electrical power was dependent on their luminous intensity distribution the electrical power of the lamps built in (to provide direct and indirect lighting the luminaire. From 2008 and likely until zones), their spectra (color temperature, around 2020, luminaires with phosphor- white point, saturation of the illuminated converted white LEDs with one fixed color objects, color gamut) and their brightness temperature, a constant luminous intensity in the relevant living or working areas distribution and a maximal luminous depending on the time of the day. efficacy of about 140-160 lm/W are Now the question is how lighting developed with an electrical power engineers will put these systematic between 10 W and 300 W for different changes into practice. Prof. Tran Quoc Khanh applications and dependent on the Prof. Khanh studied machine manufacturer. Therefore, a relative This question can only be answered at increase in luminous efficacy of 80 -100% the level of lighting science, psychology engineering and technical in the context of the discussions on and sleep research. Current standards optics before he finished “energy efficiency” is being achieved. and regulations define illuminance and his Ph.D. thesis on the luminance, glare and homogeneity Since 2014 the international lighting within the lit environment based on the spectroscopy of UV-VIS community has discussed the HCL classic knowledge of the time until 1980. radiation sources in 1989. concept on one side and smart lighting In the meantime, the dynamic Then he worked at on the other side. In this discussion development of LED technology gave rise process the focus is the development of to the usage of more modern lighting Krochmann in Berlin, technologies like Zigbee, Bluetooth or quality parameters like brightness, at Gigahertz-Optik and at Thread. Sensor concepts have the aim of visual clarity, the circadian stimulus Arnold & Richter Cinetechnik dimming the light in the illuminated space and color quality (e.g. CRI according to if the user is absent or if the natural light’s CIE 2017, color gamut or color saturation, in Munich before his incidence through the windows is enough preferred color temperature). habilitation in 2005. or it is increased by daylight optical Although these parameters are well Since then, he is professor systems (prisms, mirrors). In a general established, currently they do not find their sense, these technologies are useable way into international standards. For these for lighting technology and for energy reduction and communication parameters, minimum criterion values solid-state lighting at the technology tools. However, the question have to be specified for user acceptability Technical University Darmstadt. arises: is this the smart lighting of in order to ensure the lighting quality of the future? the smart luminaires of the future. He leads LED-research projects of the German Smart lighting has to take several different Beyond classic production methods, Central Association for Electro viewpoints into account. First, the user’s the smart luminaires of the future should illuminated space (e.g. a building, a consist of a number of modules of the Technical Industry (ZVEI) hospital or a school) always contains an same electronic and software architecture and he is chairman of the application context (e.g. the atmosphere and they should be scalable to a new International Symposium for of an office, of medical care or education), modular luminaire. Many luminaires of depends on geographical location, the this smart type in a room shall perform Automotive Lighting building’s geometry and weather and it different lighting tasks depending on Technology (ISAL). may be oriented in different directions their position in the room (e.g. next to the He recently published books (North, South, East or West). The users windows, the doors or at the walls) and who work in these illuminated spaces may communicate with each other via different on “Digital Color Imaging”, have different cultural roots, different communication channels (e.g. VLC). “Color Rendering Quality ages, genders as well as various working The lighting procedure should then be of Conventional and SSL tasks (e.g. a nurse working in different controlled by a motherboard connected to patient rooms) under different physiological the Internet platform within each lighting Light Sources” and “LED and psychological conditions depending period (e.g. 10 minutes or half an hour). Technology and Perception”. T.Q.K.

NEWS COMPONENTS 10

New Osram IR LED for “Everyone wants the reassurance that our booth demonstrate best water-proofing. Facial Recognition the data on their mobile devices is as The HNB2727 series is especially suitable secure as possible”, explained Nina Reiser, for signage applications with a pitch of Smartphones, tablets and the like can now Marketing Manager for the Emitter Laser P5-P8 mm. The HNB1921 and HNB1515 be unlocked in very different ways: with a Sensor segment at Osram Opto series are suitable for outdoor applications password, fingerprint scan or even an iris Semiconductors. “Our extremely powerful with a pitch of P2-P5 mm. In addition, scan. 2D facial recognition is another method and bright IRED illuminates the facial Everlight also provides LEDs for outdoor and involves illuminating the user’s face with characteristics of users perfectly, signage in lamp packages with narrow an infrared light source and capturing the ensuring that only authorized persons viewing angles and different sizes. image with an IR camera. The system then have access to the device.” Everlight’s outdoor LED series have all compares the image with the images passed a 3000 hour reliability test and previously stored for the purposes of This IRED for 2D facial recognition is proved luminous decay less than 10%. identification, focusing on characteristic the latest addition to Osram Opto They are certificated with IPX8, two-dimensional features. If there is a Semiconductors’ existing portfolio provide UV and sulfur resistance, match for the various data such as the for biometrics. The new Synios and wide viewing angles to present width of the mouth, length of the nasal ridge P2720 is already available for initial display effects with maximum resolution. and distance between the eyes then the customer projects. device will be unlocked. Everlight has been promoting fine-pitched LEDs for signage since 2010. As a product leader in LED packaging, we continuously Everlight Demonstrates miniaturize LEDs to ever smaller pitches. New Signage LEDs The 18-035 (0505) and 18-036 (0606) series are RGB LED packages with the Everlight Electronics Co., Ltd., a leading latest minimal size. By repeated high-density player in the global LED and optoelectronics design verification, we can implement a industry, attended Integrated Systems pitch of P0.7mm to achieve seamless Europe for the first time to demonstrate connection at micro pitch and true color. signage LED components for indoor and Products with small pitch must pass Osram's Synios P2720, the first infrared LED outdoor applications including all 13 reliability tests and luminous decay with 940 nm for 2D facial recognition, provides dimensions, packages, viewing angles, less than 5%. Everlight is the first enterprise bright and uniform illumination of the user’s face and performances. The HNB2727, HNB1921, in the industry to have passed an 8000 hour HNB1515 series for outdoor applications as reliability test. By using a wavelength of 940 nm, Synios well as 18-035(0505) for indoor signage P2720 reduces the red glow that can occur achieve true color in high resolution with For the part of special signage, with infrared light sources in the short-wave advanced technologies and have passed Everlight developed pixel sharing (virtual infrared range. Up to now, the sensitivity of multiple reliability certificates. pixel) and see-through screen applications. IR cameras was only good if the light source The 19-049 RGGB model, designed with had a wavelength of 850 nm. The cameras pixel sharing, can simultaneously drive chips have been further developed to give them in different LED packages by doubling the greater sensitivity in longer wavelength scanning frequency of the IC and reach the ranges so 940 nm light sources can now be virtual effect of a P0.6mm high-density pixel used – which in turn improves the overall for a panel in terms of vision persistence. performance of the system. Such pixel sharing can achieve the desired screen effect with micro pitch without Bright and uniform illumination of the user’s increasing the mounted quantity of LED and face or eyes is particularly important for facial SMT. For see-through screen applications, recognition and also for eye-tracking top-view LEDs are commonly used on the systems. Synios P2720 offers impressive market. Yet Everlight‘s 99-235 and 22-23 Everlight extended its broad portfolio of LEDs performance with an output of 1,150 mW for indoor and outdoor signage applications at side-view series provide smaller emission at 1 A. Thanks to this high overall output it "Integrated Systems Europe" gaps in the see-through screen and a more has a radiant intensity of 360 mW/sr. three-dimensional stereoscopic display – a For outdoor signage applications, landscaping priority of core landmark and The new Synios P2720 has the same footprint Everlight provides PLCC and Lamp business districts worldwide. as the 850 nm version. Measuring only packaged products. The PLCC-packaged 2.0x2.75x0.6 mm, the IRED is therefore series HNB2727, HNB1921 and HNB1515, By combining the R&D, business, and market ideal for space-critical applications. as well as a RGB full-color LED series in teams, plus the professional ability in the PLCC, use an enhanced structure and industry for over 35 years, we continuously The IRED has no optics. Its compact ink brush/dark support to effectively promote pursue innovation and breakthroughs on the dimensions mean that customers can install the screen consistency and contrast. package technology so as to provide perfect secondary optics in line with their requirements. All outdoor signage modules installed at products for customers.

Features and Benefits: American Bright - New The RoHS-compliant RGB LED chip is RGB LED Packages • Synchronous of two-lane well-suited for infrared and vapor phase • 8-bit (256 level) color set reflow solder process and automatic SMT with Built-in IC • 5-bit (32 level) brightness adjustment pick and place equipment. This new PLCC American Bright announced a new • Low voltage .2W power consumption RGB device features a water clear lens and series of PLCC 5050 / 3530 RGB LED chips. • Built in support for continuous oscillation is ideal for a multitude of applications The RGB PLCC chip has an integrated • Self-detection signal including indoor and outdoor commercial circuit that features self-detection signal, • Refresh rate of 400 cycles and residential lighting, light bars, and support for continuous oscillation, • 5050 and 3530 available chip sizes gaming equipment. and pulse with modulation (PWM) output that can maintain static screen. Applications: • Large LED display and backlighting • Soft light bar and rope lighting LG Innotek Introduces • Full color display New Flip-Chip Solution • Indoor and outdoor commercial and residential architectural lighting LG Innotek announced that it had succeeded • Decoration and entertainment lighting in developing an "advanced flip chip LED • Gaming Machines package" that demonstrates high efficiency and high luminous flux without deteriorating These new devices have a low power performance even after it gets through consumption of 0.2 W (max: 1 W), applied 300°C soldering process. voltage of 5V and an operating temperature The integrated circuit of American Bright's of -40°C to 70°C. The emitted red, green, The company has developed a high quality new RGB LEDs features self-detection signal blue can achieve various color mixes with flip chip LED package that dramatically 8-bit (256 level) color set with 5-bit (32 level) improves reliability by applying state-of-the- brightness adjustment. art semiconductor technologies. As a result,

it became possible to commercialize high LG Innotek developed the flip chip LED A company official said, "This high-quality flip efficacy and high luminous flux premium package by improving the internal structure chip LED package is an innovative product lighting products at both medium and of the package, designing its own that can advance the reliability of premium high power. production process, and enhancing the lighting to the new level." He also added, existing flip chip mounting technology. “We expect that its application range will be The internal structure of the chip is newly greatly expanded as the product replaces designed with its proprietary technology the existing LED packages.” to maximize the efficacy and heat dissipation performance.

In addition, the company focused on New Klaran® WD Series high quality of the product and conducted Breaks the $0.25/mW a reliability test of more than 6,000 hours. Price Barrier for UVC LEDs This “high quality flip chip LED package” achieved stable performance even when Crystal IS, a leader in developing high applied to the high temperature thermal performance UVC LEDs, announced the LG Innotek's newly developed “Advanced Flip Chip LED Package” to implement stable shock at the request of a customer. expansion of its Klaran® platform with the 220 lumens per watt efficacy Due to the strict quality verification process release of the WD series LEDs. Developed it took 2 years to develop this product, specifically for the price and performance The flip chip LED has drawn attention of which is considerably longer than the needs of POU water disinfection, Klaran WD the BLU (Back Light Unit) industry for about period required for the development of Series marks the first instance that a UVC 3 years as a high power LED light source general LED packages. LED manufacturer has demonstrated the because the electrode of the chip is directly ability to break the $0.25/mW price barrier attached to the top surface of the PCB LG Innotek has applied for 65 new required for mass production of UVC LED substrate without using a connection wire, technology patents during the development based water purification products. preventing wire disconnection and ensuring process. It has taken thorough measures The company will initially offer 30 mW and excellent heat dissipation. not only to secure its proprietary core 40 mW variants with plans to introduce more technologies but also to help its customers powerful devices in the coming months. The existing flip chip LED packages have to focus on manufacturing and sales of the been commercialized only as high power modules and finished products without LED light sources in the form of CSP worrying about patent disputes related (Chip Scale Package) in which reflective to the light source. white resin is omitted and the process is relatively simple. However, the existing The company has established a product packages distributed in the market have lineup of “high quality flip chip LED critical problems that the bonding between packages” that can be customized according the chip and the substrate melts to to lighting use. Its main product family dislocate the chip and reduces the consists of middle-power, high efficiency brightness by about 10% when exposed models in middle-power use for each color New Klaran® WD series UVC LEDs enable to high temperatures. temperature, such as 220 lm/W class 5630 water purifier OEMs to produce cost effective, 3 V products and 215 lm/W class 3030 high performance and mercury-Free water It was difficult to ensure the quality of lighting 3 V products. disinfection reactors at scale: Log reduction as a function of time for various microbes at with the existing flip chip LED packages with 3.5” distance using Klaran UVC LEDs reflective white resin as the temperature of In particular, LG Innotek has strengthened some of the processes for producing lighting its high power and high luminous flux “Our Aluminum Nitride substrates have modules and finished products reach product lineup by realizing 6 V, 9 V, and always held the promise of superior cost for 250°C or more. 12 V flip chip LED packages in series two performance at the deep UV wavelengths,” and/or two in parallel in the 3030 product said Larry Felton, CEO of Crystal IS. “Klaran The new high quality flip chip LED package family, which were previously difficult to WD series LEDs, developed specifically for developed by LG Innotek produces the high manufacture due to the package design point-of-use water, meet OEM requirements efficiency of 220 lumens per watt (lm/W) and its processing limitations in the design. at a compelling price per milliwatt to drive stably because the bonding between innovation in water purification products.” the chip and the substrate does not melt In the future, LG Innotek will continue to even at a temperature of 250° to 300°C. launch innovative and unprecedented light Klaran WD series LEDs enable OEMs to According to a representative from the source products such as automobile LEDs, address the rising global demand for water company, lighting companies can use UV LEDs, and micro LEDs by leveraging its purification products as the surge in this flip chip LED package to produce proprietary core technologies in order to industrialization, urban population and rise in premium bulbs, tubes and flat-panel lightings provide differentiated values to customers water pollution propels consumers to take a without sacrificing the light quality. and lead the market change. more active role in ensuring drinking water quality. This is exemplified in the Asia Pacific

region, specifically China and India. available 2 W optics can use Luxeon In 2015, the water purifier market in China 5050, which leads to the best flux, was valued at $4.61 billion with efficacy and color over angle expectations that this is likely to reach combination,” said Kathleen Hartnett, $11.21 billion by 2020, growing at a Senior Director, Product Marketing at CAGR of 19.45%. Lumileds. With the industry’s lowest thermal resistance (2 K/W), Luxeon 5050 The Klaran Advantage: further enhances performance by Klaran UVC LEDs are produced on a removing heat and reducing heat unique ultra-wide bandgap Aluminum sink requirements. Nitride substrate produced by Crystal IS. This substrate overcomes the material Luxeon 5050 is an ideal choice for high challenges inherent with traditional bay and street lighting applications. sapphire-based devices and emit their full Typically for high lumen fixtures that germicidal power from the top of the chip, require a high lm/W, a group of standard allowing for low cost, simpler packaging mid power LEDs would be used, with the design. The resulting UVC LEDs offer tradeoff of a large fixture size and weight. high output at peak germicidal Using Luxeon 5050, on the other hand, wavelengths (260-275 nm) and the ability enables overall smaller system size, to be operated at high drive currents for which means very compact fixtures more effective disinfection. are possible. Luxeon 5050 is available in a range of color temperatures (2700–6500 K) and CRI levels (70, 80, 90) to meet a variety of high bay and street lighting as well as Lumileds Increases indoor spotlighting needs. Luxeon 5050 LEDs Performance

Lumileds introduced an upgraded Luxeon Nichia Ultra-High CRI 5050 that sets the standard for high White LED - Optisolis™ lumen per watt (lm/W) for high bay and street lighting applications. With newly Since the birth of humans, light (AKARI) released LM-80 reliability data, has been indispensable. Light generates the product also meets DLC Premium such a strong feeling, it has kept people V4.1 requirements, enabling fixture throughout history longing for lighting manufacturers’ access to high utility that is most similar to that of natural rebates and energy savings. daylight or fire. To further improve the overall quality of light as "AKARI”, Nichia Corporation has developed an Ultra-High Color Rendering white LED named Optisolis™.

Lumileds' Luxeon 5050 performance breakthrough enables DLC premium fixtures for outdoor and industrial markets featuring the highest flux, efficiency and robustness at excellent cost-per-lumen

Nichia's new Optisolis™ LED is characterized Luxeon 5050 features the best by an incredibly high CRI which can performance of all multi-die emitters already be supposed when comparing the on the market, reaching flux levels of 5000 K LED's spectrum with sunlight (inset) due to its almost perfect match 350 lm and 175 lm/W at 2 W LED drive conditions (4000 K, 70 CRI at 85°C). But the advantage goes beyond superior As Nichia continues to lead the industry flux. The round LES (4.6 mm), eases optic with innovative products, Optisolis™, design. “The majority of commercially which launches in February 2018,

achieves Ultra High CRI with a spectrum that temperature requirements that make a the supply chain’s upstream and demonstrates the closest match to that of space comfortable, Everlight developed downstream core competence the standard illuminant. Optisolis™, its new 5630X Series with a high efficacy effectively to deliver products at which was first presented to the industry at of 228 lm/W (@65 mA 5000 K CRI>80), a high capacity and low cost with The Phosphor Global Summit in 2016, which is in compliance with DLC4.0 fast services, providing competitive is optimized for the general lighting market standard. After passing HTOL (high cost-performance ratio and excellent and is accomplished by using Nichia’s own temperature operating life) at 105°C, service to our highly valued customer. blue chip and phosphor technology. 5630X LEDs can meet L90>36,000 hours and a color shift less than 3SDCM. Samples Available: Yes. (Upon request Manufacturers can utilize Optisolis™ and Compared to standard LED lamps according to customers’ requirements) - trust in a spectrum where all colors are (2000 lm), the 5630X Series can Mass Production: now (Q1/2018). reproduced to the color seen under a efficiently reduce power consumption standard light. Most importantly, since UV by 30-40%. With superior optical efficiency emission is essentially non-existent in the and reliability, the 5630X Series are perfect spectrum, the degradation of irradiated for professional, commercial and industrial Plessey - Monolithic materials can be reduced dramatically lighting applications. microLED Displays compared to that of other light sources containing UV emission, including other Plessey Semiconductor, a leading developer market available LEDs. of award-winning optoelectronic technology solutions, announces its commitment to Optisolis™ target applications include being the first to market with a monolithic Museum and Art Gallery Lighting, where the microLED based display based on highest CRI is preferred, but UV radiation GaN-on-Silicon. and light sources can be detrimental. Additional applications could include Color Plessey has also commenced an extensive Evaluation, e.g. painting, printing), licensing program that will see the company Commercial Lighting (e.g. retail, etc.) or license out its GaN-on-Silicon expertise to anywhere Ultra High CRI is desired. Everlight's latest 5630X LED series is the microLED manufacturers in line with its industry leading lighting series with highest new business strategy of becoming the luminous efficiency of 228 lm/W photonic industry’s foremost technology platform provider. Everlight Presents For more than 35 years, Everlight has 5630X LED Series dedicated and devoted its resources to the development of the LED industry. Everlight, a leading player in the global LED In order to provide an even more and optoelectronics industry, applied its comprehensive product portfolio latest technology into the development of the in the lighting field, Everlight now offers new 5630X Series, a new lighting LED with a full range of products from mid up to 228 lm/W (5000 K) in luminous efficacy and high power LEDs to even the ultra meets the highest luminance requirements of high power COB. The 5630X is designed professional commercial and industrial with a long term experience on development lighting applications. and testing processes that focuses There are numerous interesting applications on improving the efficacy, form factor, for microLEDs, especially for microLED People today, with an increasing sense for cost-performance ratio and heat displays. But with a non-monolithic approach, a better quality of life, put more emphasis dissipation to meet different design the placement of LED chips onto a CMOS backplane is a huge challenge on the quality of their lighting environment. demands. Everlight’s pursuit of high In order to meet the illuminance and color technology and quality combines

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BCR430U is the best choice to drive low power LED strings and strips supplied by a DC voltage source, allowing for more flexibility in voltage headroom, compensating tolerances of LED forward voltage or supply voltage. The voltage drop can typically go down to 135 mV improving the overall system efficiency. Learn more and download Datasheet! www.infineon.com/bcr430u

Demand for microLED displays is of microLED displays to address place equipment and isn’t subject to accelerating with research consultancy emerging applications.” the associated productivity issues. Yole Développement forecasting the market could reach up to 330 million units by 2025. One of the main challenges involved A fully monolithic approach also supports GaN-on-Silicon is the only technology with manufacturing microLED displays the integration of the standard CMOS platform capable of addressing all of the using a non-monolithic approach is the circuitry necessary for driving microLED challenges involved with manufacturing placement of LED chips onto a CMOS displays, as well as the close integration of microLED displays in high volumes and backplane, currently achieved using pick high performance graphic processing units cost-effectiveness, Plessey intends to and place equipment. This involves the (GPUs), all of which can be carried out using demonstrate its expertise in the field by individual placement of every LED on a standard CMOS manufacturing methods. being the first to manufacture a monolithic pitch of less than 50μm, requiring new By solving all of the major challenges, display based on microLEDs fabricated and expensive equipment that is subject licensees gain instant access to a using a GaN-on-Silicon approach. to productivity issues. As the pixel density technology platform that is ready for of displays increases and pitch reduces, volume production. “We made the decision to become a pick and place becomes less feasible technology platform provider in order to both commercially and technically. “GaN on Silicon is the only technology get our technology out to the widest that makes sense in terms of scalability possible manufacturing base to meet this Moving to a monolithic process removes and performance,” commented Dr Keith growing demand,” explained Michael the need for chip placement and will Strickland, CTO, Plessey Semiconductor. LeGoff, CEO, Plessey Semiconductor. enable smaller and higher resolution “It offers better thermal conductivity than “By being the first to market with a displays for a range of applications, Sapphire and higher luminosity than monolithic microLED display we will including virtual reality (VR), augmented OLED, which is why this technology is be demonstrating our expertise and reality (AR), and head-up displays. widely acknowledged to be the only the ability to access our proven turn-key As the only monolithic solution one that can deliver high resolution, solution, enabling manufacturers to commercially available, Plessey’s high luminance displays.” ramp up the development and production technology doesn’t require pick and

A Revolution in Optics direction, which will accelerate the High levels of efficiency, low color from IQ Structures lighting market, change the design tolerance, long lifetime: of light fixtures, output performance, With the appropriate driver, the modules Brand new revolutionary lenses for luminaires and bring new, previously unimaginable, achieve efficiency levels of up to 170 lm/W come to the market under the trade name features. and provide a luminous flux of 650, 1250 and NANOPTIQS. This is a completely new 2000 lm/ft depending on the length. The LED approach to designing and manufacturing “NANOPTIQS lenses are currently modules are available with different color lenses using calculated surface nano- and positioned in front of LED light sources, temperatures in order to cover different micro-structures. as is the case with conventional, usage scenarios: 2,700 K, 3,000 K, 3,500 K, commercially available lenses. 4,000 K and 5,000 K. The color rendering In addition, IQ Structures, together with index Ra > 80 demonstrates the quality of the company Crytur, is developing the light, while MacAdam 3 represents low the first application of NANOPTIQS color tolerance levels. The homogeneity of used directly on the surface of LED the light is also retained when multiple phosphor lamps,” says Tomáš Těthal, LLE-G4 modules are arranged in sequence. CEO of IQ Structures. Plug-in terminals are available for simple and quick wiring. The manufacturer also offers light covers for these modules for different A Complete Light Band light distribution options. Once installed the IQ Structures award winning NANOPTIQS Covering ZHAGA- LED modules achieve a lifetime of 50,000 lenses may be a game-changer in the LED hours. Tridonic provides a 5-year warranty. lighting industry Compatible Lengths The fourth generation LLE-ADVANCED NANOPTIQS lenses are suitable for all types modules have been expanded to cover of luminaires and can be designed for linear ZHAGA-compatible lengths, meaning that Bilton Realizes a lighting, down lights, spotlights, wall wash very long homogeneous light bands such as Fully Encapsulated and other applications. They can also be might be used in office buildings can also LED Module used in automobiles. now be implemented with no additional wiring effort. With the new Bilton AIR series, Bilton is Main Product advantages: presenting innovative and avant-garde ideas • New design options that will revolutionize the future of LED • Huge flexibility in functional applications lighting. This is achieved through a • Possibility of miniaturization of the progressive hybrid solution. The new Bilton luminaires LED module series Bilton AIR is a highly • A highly productive way of producing flexible silicone hose and, in addition to optics while saving material, protection class IP67, guarantees top light time and energy quality, effective heat dissipation and is • Highly effective resistant to external influences (UV, salt, chlorine, etc.). This innovation is brought to the market Tridonic's new, extra long (inset) and small by IQ Structures, the world leader in linear modules offer homogeneous linear Top features: computer-generated optical and lighting plus reduced wiring requirements • IP protection IP67 holographic components. • Flexibly shapeable The new 1120 and 1400 mm module • Lighting upwards or sidewards IQ Structures won an award in the lengths significantly expand the design • Max. module length up to 5 meters International Design Plus Competition in options available for linear luminaires • Luminous flux up to 1,000 lm/m January 2018 for their “COB-NANOPTIQS and panel lights, without increasing the • Voltage 24 VDC flat lens”, as well as the IHMA Award for a amount of wiring required. The lengths • CRI >80 synthetic computer-generated hologram in equate to multiples of existing ZHAGA • Light color available in 2,700, 3,200 and November 2017. modules, meaning that existing mounting 4,000 K holes can still be used. The smallest The arrival of the revolutionary of the new modules measures just The LED strip light is flexibly shapeable. Nanoptiqs lens meets the prediction 70 mm and allows gaps to be filled in There are two versions of the Bilton AIR SIDE - of the research and consulting firm the luminaires and shadow effects with lighting from the side, and the Bilton Lux Research, which predicted back through the connector to be avoided. AIR TOP - with lighting facing up. Both model in 2013 that major changes on the The new modules do not differ from versions are available in 3 different light lighting market will be coupled with the the LLE-G4 standard modules in colors. Bilton AIR bends in every direction, LEDs and linked advanced technologies. their specifications. making the LED strip light perfect for any IQ Structures brings an absolutely new application – indoors and outdoors!

We are showcasing real innovation at (KitKat), an iPhone 4S with iOS 5.0 or Light and Building 2018. The hybrid an iPAD 3 with iOS 5.1. Firmware solution of the Bilton AIR series realizes updates can also be installed via the the novel design of a completely mobile terminals. encapsulated LED strip light. Come along and see the innovations Control via a smart button or app: for yourself. We want you to go beyond The pre-configured button for wall the limits of feasibility and, under our mounting works using batteries. It has a motto “The Art of Linear Lighting”, clear and manageable control panel with we want show you inspired and versatile eight buttons that can be used to switch works of lighting art that can be luminaires on and off or for the dimming achieved with LED modules. functions. In addition, light settings can be accessed and color temperatures set.

The luminaires are automatically scanned Tridonic basicDIM for and detected using the free apps for Wireless Light Control Android or iOS. The intuitive interface allows users, for example, to set up Tridonic's compact basicDIM wireless groups of luminaires, create different control module paves the way for easy light settings, implement Tunable wireless communication with up to 127 White settings and define and control luminaires. It is suited primarily to projects dimming levels. The wireless light control that need no direct IP connection and supports users with establishing and that aim to achieve more lighting comfort configuring the lighting control options, in a cost-effective manner and with no enhances lighting comfort and helps additional wiring. save energy.

Infineon Introduces BCR430U to Improve Efficiency of LED Strips

Infineon Technologies AG releases BCR430U, a constant current linear LED driver IC. The BCR430U provides Tridonic's new basicDIM wireless industry-leading drop performance control system consists of a compact control module and a smart button for regulating LED current in standalone as user interface operation. No external power transistor is needed. Typical applications for The compact control module can be the BCR430U include LED strips, integrated into existing luminaires easily architectural LED lighting, LED displays and establishes a mesh communication as well as retail, appliance and network automatically. Communication is emergency lighting. wireless via Bluetooth 4.0, and therefore requires no DALI wiring. The module is fitted with a configurable 1-10 V and DALI interface along with a switched relay contact, and allows dimming functions and even color temperature controls to be implemented with ease. Groups can also be set up and scenes can be created.

The luminaires can then be controlled via an associated smart button (user interface), or using the corresponding free apps on mobile terminals that run on Android or BCR430U improves efficiency for LED iOS operating systems. The minimum strips with an ultra-low voltage drop system requirements are Android 4.4 linear LED driver IC

The voltage drop at the integrated driver applicable in medical, industrial and IC can go down to 135 mV at 50 mA. commercial environments. This improves overall efficiency and provides the voltage headroom required to The BCR420UFD and BCR421UFD linear compensate for LED forward voltage constant current regulators for LED lighting tolerances and variances in the supply are available in production volumes now, voltage. Thus, more flexibility in the lighting priced at 0.11 USD each in 3K piece design is possible. With the BRCU430U, quantities. additional LEDs can be added to lighting designs without changing the supply voltage. Diodes' new constant-current LED drivers in a low-profile DFN package are especially The LED driver current ranges between Digi International - suitable for edge lighting 5 mA and 100 mA, and can be easily New Smart Edge IoT adjusted via high ohmic resistor on a Like other members of the BCR4xxU series, Modules and Modems dedicated pin. The supply voltage ranges the new devices can deliver an adjustable between 6 V and 42 V. For safe and reliable constant current between 10 mA and 200 Digi International®, a leading global provider operation and to extend the LED lifetime, mA (BCR420UFD) or 350 mA (BCR421UFD) of Internet of Things (IoT) connectivity a smart over-temperature controlling circuit with ±10% tolerance, which in the case of the products and services, announced the reduces the LED current when the junction BCR421UFD can be controlled using a PWM availability of the Digi® XBee3™ series of temperature is very high. signal of up to 25 kHz and a duty cycle of 1% next-generation RF modules and cellular to provide LED dimming functionality. Both modems. Introducing a new micro form devices include a negative temperature factor option capable of supporting greater coefficient, which lowers the LED driver IoT innovation at the network edge, Constant-Current current as the internal temperature rises, Digi XBee3 series extends its modular LED Drivers in Low- thereby protecting and extending the lifetime approach to IoT connectivity, enabling the Profile DFN Package of the LEDs. In addition, the linear topology integration of new functions as needs arise used is based on an NPN emitter- and regional requirements change. Included In response to growing demand for smaller follower with emitter resistor, which means the in its micro size, Digi XBee3 also offers LED lighting installations that also provide devices exhibit virtually no EMI, making them MicroPython programmability and dual- high efficiency and ultra-low EMI, Diodes well-suited for sensitive applications such as mode radios that provide wireless design Incorporated has extended its popular medical lighting. flexibility and enable easily added BCR420U and BCR421U families of linear functionality for innovative IoT solutions that LED drivers to include the BCR420UFD With a wide operating voltage range of can be more quickly developed, prototyped and BCR421UFD devices in the ultra-low between 1.4 V and 40 V and total power and mass-produced. profile DFN2020 package, making them dissipation of up to 1.7 W, the devices can be well-suited for 12 V and 24 V LED edge- used to drive longer strings of LEDs while still lighting applications. providing sufficient protection from transients in a 24 V system. Designed as monolithic The primary benefits of LED lighting, namely solutions, the devices integrate transistors, longer lifetime and higher efficiencies, means diodes and resistors in a single package there is growing demand for more varied and measuring just 0.6 mm high. This is much less intrusive solutions. This includes fittings thinner than the standard SOT26 package, that emit light from the edges as opposed to allowing engineers, architects and lighting vertically. In order to meet this demand, designers to develop LED fitments with a manufacturers are looking for solutions much lower overall profile, for a wider range Digi XBee3 includes new micro form factors: RF modules and cellular modems feature that support a thinner overall profile. of applications. Edge lighting is now being programmability and flexible architecture, At just 0.6 mm in height, the DFN2020 specified in areas such as emergency, mood providing modular agility for advanced IoT package is uniquely suited to edge lighting. or decorative lighting, but is equally edge connectivity

Cree® XLamp® XD16 LED First to Surpass the 280 lm/mm² Lumen Density Mark

The XLamp XD16 LED delivers a lumen density of more than 280 lm/mm2, the highest level achieved by a commercial lighting-class LED. The ceramic-based XD16 LED uses the proven XQ footprint and combines breakthrough lumen density, low optical cross-talk, unsurpassed thermal contact and ease of system manufacturing to enable new designs for lighting such as color-tuning, street, portable & industrial. For more details, please visit Cree's XLamp® XD16 LED webpage

Digi XBee3 Advanced Capabilities: Micro, SMT and Through-hole Micro Module With Big Features: • Easy over-the-air (OTA) changes to devices Form Factors: With its reduced size, weight and power in the field for bug fixes and new features At one-third the size of the original Digi XBee consumption, Digi XBee3 series is ideal for • Dynamically reconfigurable, based upon RF module, the Digi XBee3 micro form factor compact and battery-powered applications. situation (13x19 mm) is one of the industry’s smallest Digi XBee3 delivers multiple levels of • Easily establish business rules to MicroPython-programmable modules programmability including dual-mode radios, aggregate, store, transform and filter data capable of providing RF connectivity for MicroPython for both business rule and via MicroPython programming capability short range and Low Power Wide Area application logic, and the tools to manage • Create alerts and alarms for priority data Network (LPWAN) applications. it all. In addition to edge programmability, and device health it offers a low-power microcontroller capable • Built-in support for advanced I/O including I²C, Also available in the existing Digi XBee SMT of delivering intelligence at the network edge, SPI, to drive modern sensors and actuators and through-hole form factors, the Digi and the ability to switch between a variety of • Provide control logic for devices that XBee3 micro, when installed on interposer protocols without changing the device. require a microcontroller, without boards, automatically provides all the With the built-in Digi TrustFence® security electronics redesign benefits inherent in the industry’s smallest framework, all Digi XBee3 products offer • With Digi Remote Manager®, enables RF module capable of supporting the U.FL, Pad, or Chip antenna options. better bandwidth management via development of truly innovative, smart IoT prioritization/ transmission of actionable solutions. Additionally, the through-hole form Design Flexibility: information factor is ideal as a validation and migration Digi XBee3 series will be initially available in • Dynamic changes to behavior as platform for those requiring the advanced both RF (ZigBee 3.0, IEEE 802.15.4) and requested from cloud platforms such as capabilities and features necessary to speed cellular options (Cellular Cat-1). Over the next AWS and Azure (e.g., enabling real-time development, prototyping, or early- several months, Digi XBee3 will be software- decisions based on local conditions) production phase. Digi XBee3 Cellular is upgradeable to Bluetooth LE and will also be • Continue to operate during available in its original, classic through-hole available in additional RF protocols communications outages by dynamically form factor. (DigiMesh® and Wi-Fi) and two cellular executed logic that is not cloud-dependent modems (Cellular LTE-M and Cellular NB-IoT.)

Development Kit Availability: exceptional thermal performance and a total their communication modules and The Digi XBee3 ZigBee Mesh Kit is available harmonic distortion (THD) under 10%. sensors to their specific needs. for evaluation and testing. The kit includes The intelligence is decentralized – three Digi XBee3 modules along with three The EUC-30SxxxDTM/DVM provides a each luminaire becomes an intelligent Digi XBee Grove Development Boards higher input surge protection with 4kV node within the building network. allowing customers to build a ZigBee mesh line-to-line and 6kV line-to-earth and network right out of the box. incorporates input under voltage (IUVP) The high speed of bidirectional communication and input over voltage (IOVP) protection between the ECG and connected components “With the development of the Digi XBee3, for installations where the power may provides high levels of lighting convenience – we’ve combined advanced features and be unstable. DTM versions are IP66 rated completely without noticeable delay times flexibility in a micro form factor to offer the and suitable for built-in use while DVM as often experienced in larger DALI very first ‘Smart Edge’ IoT module,” said versions are IP67 rated and suitable applications. In addition to the Z-COM Scott Nelson, vice president of product for for independent use. interface, the electronic control gear units Digi. “With intelligence moving to the edge of also feature a standardized DALI interface. IoT networks, the market needs hardware The new series offers 3 models that deliver that is very capable, very adaptable, secure 350, 500 and 700 mA of output current. ECG and software as a and extendable. What we’ve provided in Digi They are highly reliable and have a high-performance unit: XBee3 is a module that can deliver solutions calculated lifetime to be at least 88,000 hours The intelligent ECG forms a high- capable of aggregating and analyzing data when operating at 80% load with a case performance unit together with the also where it is captured on a distributed network, temperature of 75˚C. newly developed EXELIQO application and apply specific business rules and software. Desired configurations, ECG application logic – essentially the next The EUC-030SxxxDTM/DVM models are functions and settings are individually generation of IoT applications.” approved to UL, FCC, CE, KS, TUV, CB and implemented with the software. CCC standards. Production quantities are These include precise setting of output available now. current, temperature-dependent control o f output current, compensation of LED Inventronics Expands degradation (CLO) and measuring of the Family of Low-Power, ECG temperature. The complete system OEM Systems Group's Compact LED Drivers scores with its open architecture, so that New Offer for the users can already today efficiently and The EUC Family of constant-current LED Digitalization of Light flexibly implement future-safe solutions drivers is ideal for lower power luminaires such as networked systems or simple that may be subject to environment and Mega-trends such as digitalization or the data exchange. space constrained challenges. They are Internet of Things will fundamentally change available in popular fixed output currents and lighting technology in coming years. Four Main Focus Applications: offer increased flexibility through isolated Solutions are in demand that bring together • Wireless control: Communication modules 0-10 V dimming and a compact shape that intelligent control, connectivity, flexibility and connected via Bluetooth for example to the allows them to be installed in space the possibility to individualize. Today, the new Z-COM interface enable ZITARES wiz to constrained luminaires. LED electronic control gear units from the regulate the light without need of additional OEM Systems Group in the ZITARES wiz control lines. This cuts installation effort series already point the way towards this significantly. Supplementary central networked future. The LED ECGs represent a controllers are superfluous, enabling high-performance unit together with the simple scalability correspondingly new EXELIQO software. • Light management: The open Z-COM interface means easy integration of sensors, e.g. for presence detection and the daylight-dependent light control of luminaires • Programming of parameters: Parameters Inventroncis' new EUC driver family is ideal for applications that may be subject to and functions are flexibly adaptable and environment and space constrained challenges The LED ECG ZITARES wiz and the EXELIQO modifiable both during luminaire software form a single unit – connectivity and production and subsequently. intelligent control for greater flexibility The EUC family is expanding to include 30 W For example, adaption of the LED operating models whose compact metal housing is current or to ensure constant lumen output ideal for flood, wall packs, and architectural An open interface provides (CLO) over the complete life time decorative lighting applications, as well as maximum flexibility: • Monitoring & maintenance: Individual low-power street lighting. The new 30 W ZITARES wiz offers a decisive advantage ECG operating data can be recorded. series compliments the existing 26 W, 35 W, with the digital Z-COM interface. This provides completely new possibilities 40 W and 60 W models. They operate over a The open protocol (API) enables for predictive maintenance and the 90-305 Vac input range while providing luminaire producers to custom-connect measurement of energy consumption

The first generation of the ZITARES wiz electronic control gear unit – the series is being consistently expanded in the coming months – is accompanied by matched system components. These include the Bluetooth module based on reliable technology from CASAMBI and a daylight- and presence sensor for direct connection to the electronic control gear unit. In addition to these system components available from OEM Systems Group, luminaire producers can also integrate other components and technologies (e.g. ZigBee, EnOcean etc.) – matching these to the Z-COM interface is possible thanks to the open source platform.

MechaTronix Unveils CoolStar® Series of Designer LED Coolers

“Because looks do count”, that was the basic idea when MechaTronix started to develop their next platform of spot light, down light and shop light coolers. Inspiration for the design was searched in natural elements which express the feeling of cool or cold.

With its new CoolStar® Series, MechaTronix provides heat sinks that, based on the "form follows function principle", satisfy the increasing aesthetic demands - “because looks do count”

The result is an impressive series of new LED coolers with a stunning high end look. Koen Vangorp, CEO of MechaTronix “Although the first priority of a LED cooler remains a maximal cooling capacity in a limited volume, also the looks of the product are of great importance. Even recessed downlights and shop lights, where the majority of the volume is hidden in the ceiling, first need to be sold to the customer. And during that decision phase the LED cooler takes a big part of the looks for its account.”

The CoolStar® family covers the whole range of cooling capacity from 1000 lumen all the way up to 6000 lumen, which positions them as well in the spot light developments as in the down light and shop light luminaires. The modularity in LED engines which can be mounted either directly or with a LED holder (ref. BJB, TE Connectivity, Bender Wirth) is respected on each design. On top of that some practical features have been added, like two closed wire pockets at the sides which allow to guide the wiring from the LED engine to the back side outside the visible field. Besides the black anodized versions which are commonly used, MechaTronix has also opted this time for a “pure white” electro- plating as an option, underlining the

high-end looks and blending with the During the moistening, air escapes out of “Since we launched the Type Z50 LED mostly white looks of both the LED engines the area of the boundary layer which leads holder less than six months ago, response and the LED holders. to a significant reduction of the thermal from the market has been very encouraging,” impedance and simultaneously to an optimal says Jonathan Catchpole, systems architect Koen Vangorp “The biggest challenge was, heat transfer resistance. The material & business development at TE. “At TE we for sure, to reach the uncompromised thicknesses vary from 0,114 mm up to aim to make engineers job’s easier and cooling performance the CoolStar® stands 0,2 mm whereby the customers can select accelerate the development process for for without losing the looks we had in mind. the particular material thickness contact technologists. The new development kit It took us over six months and an endless surfaces depending on the unevenness makes it easier for luminaire designers to amount of CDF thermal simulations to get and roughness. appreciate its advantages and work out how to perfection. Certainly in the smallest best to integrate it into their new products.” diameters a very big step forward was made The thermal conductivity of the new designs in cooling performance with a gain of over is within the scope of 1,5 up to 2 W/mK. Designed for 48 VDC input, the Lumawise 35% compared to similar diameters on the For a simple handling (easier installation) in Drive LED holder Type Z50 works with a wide market. Also this time we played on safe, the application both types have a one-sided range of readily available constant voltage patenting the whole series according the natural adhesive layer. The basic material of power supplies, making it possible to power Hague System, which gives us design the article FSF 15 P is available as sheet or multiple fixtures off a single power supply. protection in all major parts of the world.” roll material whereas the FSF 20 P is only Designers can also remove driver boxes from available as sheet material in the dimension spot and track lighting, creating a more 300x400 mm. Special cuts and contours aesthetically pleasing and lower-cost of the phase change materials will be solution. Further functionality can be added Fischer Elektronik - performed according to customized to the holder with an optional 0-10 V dimmer. Phase Change Thermal drawing specifications by means of latest Conductive Material processing machines. The Lumawise Drive LED Holder Type Z50 provides thermal and electrical connection Company Fischer Elektronik GmbH & Co. KG to four different COB sizes – 16x19 mm, extends their extensive product portfolio of 19x19 mm, 20x24 mm and 24x24 mm – thermal contact materials by new phase TE Connectivity - New and has four different current outputs: change thermal conductive materials which Lumawise Drive LED 350, 500, 700, and 1050 mA. provide an alternative to the conventional Holder Development Kit thermal conductive pastes. TE Connectivity (TE) has introduced a development kit for its Lumawise Drive LED Adels-Contact Holder Type Z50, enabling luminaire designers Introduces LEDtrack – to purchase a single unit for desktop testing, LCS 75 – SMDblank product evaluation and luminaire prototyping. Each kit contains an LED holder, a cable On 18 March it will be that time again: assembly and a thermal interface material. The world’s leading trade fair for lighting and building technology, Light + Building 2018, with more than 2,600 exhibitors, will open its doors. Along with their well-known solutions, Adels-Contact will present three Fischer Elektronik's new FSF 15P and FSF 20P innovations that impress with their quality phase change material is available as sheet or and reliable functionality. roll material and can be customized

The new material types combine the advantages of high thermal performance together with the reliability of phase change Luminaire designers can now test and materials and with a simple application on evaluate the Lumawise Drive LED Holder Type the surfaces to be contacted. Z50 with development kit from TE Connectivity

The thermal conductive material with the The Lumawise Drive LED holder Type Z50, designation FSF 15 P and FSF 20 P is solid in launched last September, has a built-in its delivered condition and begins to flow at a low-profile DC/DC driver that brings At Light + Building 2018, Adels-Contact will phase change temperature between 52°C integrated functionality and flicker-free launch the LCS 75 – smart connection for IP66 and 48°C each. Hereby, microscopically illumination to the company’s successful luminaires, the LEDtrack – one single system small unevenness between heat source and range of Zhaga-inspired Z50 LED holders for for all functions in a lighting strip, and the SMDblank – the smallest SMD connector with a heat sink, for example, will be compensated. COB LED for spot and track lighting, two connection options without any change to outside dimensions.

LEDtrack – the Optimum Connection of in next to no time. The manufacturer GRE Alpha Introduces Lighting Strip Systems supplies the luminaire with a pre-assembled EnOcean Wireless With the LEDtrack, Adels-Contact offers for LCS 75 connector. There is no longer a the first time a special solution for lighting need to open the luminaire, as the Dimming Module strip systems for use in large-scale industrial electrician connects it from the outside. GRE Alpha announced the release of its buildings, such as production halls, Installation time and errors in electrical cutting-edge ENO-DIM dimming module warehouses or supermarkets. The complete installation are minimized while time and with integrated EnOcean technology. system is attractive, due to its diversity. costs are saved. The spring-loaded terminal simplifies Apart from the mains supply, it allows for installation and is compatible with any the integration of DALI, emergency lighting SMDblank – Extremely Small SMD EnOcean-enabled wireless switch. and sensors. Depending on the customers’ Connectors without Mouldings With the ready to install dimming module, it's needs, it is possible to provide the LEDtrack The SMDblank extends the SMD connector just plug and play. The ENO-DIM is available with 5, 7, 9 or 11 poles. Its small form product portfolio by a moulding-free in three regional frequency versions: 902 allows manufacturers to design extremely variant. The innovative concept offers MHz in North America, 928 MHz in Japan, flat and narrow lighting strips. Installation two versions in one. Connection can be and 868 MHz in Europe and China. without tools, as well as free positioning, made horizontally with solid or flexible are convincing arguments when installing conductors. Alternatively, it is possible to on site. use the vertical feed-through version for solid conductors – depending on the LCS 75 – Intelligent Connection Solutions customer’s individual needs. With a height for IP66 Water-Proof Luminaires of only 2.5 mm the SMDblank is a very The LCS 75 presents an advanced small connector type that has nevertheless development of our patented LCS 45. been optimized for the nozzle removal No matter whether for underground car from the tape-on-reel packaging. The ENO-DIM combines EnOcean's self- parks, trade fair halls or industrial buildings: powering technology with GRE Alpha's Luminaires up to IP code 66 are connected dimming technology

The single-channel ENO-DIM module hooks With its wide spectral range from 360 nm to its doors in Frankfurt am Main in March. up to any constant voltage LED driver, 830 nm the CSS-45 is ideal, for example, The AOI and LED testing of rolled LED including an existing DC power distribution as a high accuracy photometric and ribbons is thus possible. panel or at any point in an existing lighting colorimetric detector (according to CIE circuit. The ENO-DIM module operates at a S023). The precision diffuser provides maximum 5 Amp capacity and can support excellent cosine correction (f2 ≤ 1.5 %). up to 30 EnOcean wireless energy- The optical bandwidth correction feature harvesting devices. The module adheres to (CIE 214) further improves the quality of the UL8750 standards and is IP20-rated. spectral measurement data. Manual and auto gain settings enable a wide This dimming module makes it possible to measurement from 1 lx to 350,000 lx for easily retrofit existing wired lighting control illuminance and color measurements. systems with simple to install EnOcean- enabled wireless switches. These switches Additional functions of the CSS-45: Automated flexible LED ribbon testing is no utilize the energy created by the touch of a The embedded intelligence of the CSS-45 simple task, but Schneider & Koch did the job button to send a wireless signal to the enables the direct output of a comprehensive ENO-DIM module. There are no batteries or range of radiometric, photometric and With the further development, Schneider & wires required, and switches can be colorimetric parameters based on the Koch is clearly pursuing its own corporate mounted anywhere. measured spectral data. strategy of aligning existing inspection systems even more closely with customer ENO-DIM applications include architectural Additionally, specialist functions are requirements. "When we talk about the lighting, effect and contour lighting, incorporated for particular applications testing of LED products, we've also got general commercial illumination, fields including: to think about how rolled LED ribbons warehouses, signage, strip lighting and • Horticultural lighting – PAR measurement can be tested. That's why we've decided more. The ENO-DIM dimming module is Photosynthetic Photon Flux Density (PPFD) to continue developing the existing one of the most innovative products in the in μmol/m²s LaserVision-LED system for testing these industry. By combining GRE Alpha’s dimming • Human Centric Lighting – melanopic luminants. Technically, this demands some technology with EnOcean's self-powered irradiance and illuminance, melanopic changes inside of the machine," explains sensors and switches, GRE Alpha is paving daylight equivalent illuminance Ronald Block, managing partner at the way for industrial lighting systems that • Phototherapy – total irradiance for bilirubin, Schneider & Koch. are sustainable and energy-efficient. Ebi, in mW/cm² (IEC 60601-2-50) as well as average spectral irradiance in μW/cm²/ Position monitoring is especially nm (American Academy of Pediatrics) challenging, because the LED ribbons are very flexible. The monitoring is done during Gigahertz-Optik Options for the CSS-45: handling, whereby contacting is also Introduces the CSS-45 • Software development kit for integration of ensured. This contacting occurs in the Remote Spectral Detector the device in the user’s own software edge area and presupposes repeat contacting. Because the user often cut The CSS-45 detector incorporates a powerful The robust housing and its connectors LED ribbons to the desired size, the roll microprocessor which performs not only data are splash proof, and therefore suitable material often contains recurring units. acquisition but also all necessary lighting for use in industrial applications. A variant That's why repeat contacting is possible. calculations. Both USB 2.0 and RS 485 with protective glass dome in front of the The ribbons can be up to 600 mm wide. interfaces are standard, enabling the flexible diffuser is available. A special feature of the No roll length is defined. That way, configuration of single and multi-detector detector is its remote-controlled shutter, different LED ribbons with differently placed based systems. An optional software which allows a dark level measurement LEDs can also be tested on a single roll. development kit supports integration into to be made at any time. But separate ribbons on different rolls can third party application software. also be simultaneously inspected.

The power supply's ability to supply the LaserVision-LED entire roll, or several rolls in parallel if Inspection System with needed, must be guaranteed while the Reel-to-reel Option rolls are being inspected. The maximum current is not needed, because a test Prüftechnik Schneider & Koch can also succeed at low power. It is Ingenieurgesellschaft mbH is further important, because of intense heat expanding the LED inspection range for their generation in such cases, that LED rolls LaserVision LED. The Bremen-based AOI are not permanently energized. The heat Gigahertz-Optik CSS-45 detector head, side specialist is presenting a reel-to-reel option generation can be controlled with a view (left) and top view (right) to the professional public for the first time at targeted current feed that can be the Light & Building trade fair, which opens switched via a matrix.

NEWS APPLICATIONS 26

A vacuum table fixes the LED ribbons Phoseon UV-C LED - during the inspection process. The test Performance Boost head is mounted on an X/Y axis and travels to the individual inspection points. Phoseon Technology announces that utilizing Complete testing of the assemblies is its patented SLM™ technology and proprietary possible in the process. This includes thermal management system achieves a AOI testing as well as testing of the breakthrough level of deep-UV irradiance LEDs regarding their light parameters. targeted at disinfection and decontamination There are two different testing approaches Life Science applications. Phoseon is the first for LED tests. The cycle-time-optimized to develop a 275 nm UV LED disinfection Selteka‘s new developed luminaire Skylighter approach employs the camera used for (installation Suspended) from family SL-B6- system that surpasses 5 W/cm², significantly testing during AOI. Testing can certainly 2765-1 even alone and without external higher than the 0.3 W/cm² levels reached by also be conducted via an integrated controller can provide automatic circadian other technologies in the market. lighting with color rendition Ra>95, R9>90ll spectrometer. However, this is not fundamentally necessary, because the camera often delivers adequate results. BIOWN Light Technology The spectrometer can be drawn upon for Smart LED Lighting System: Biodynamic more exact measurements. Because a BIOWN light technology is developed by the very slow spectrometer measuring, it's Lithuanian company Selteka in collaboration unsuitable for use in mass production. with scientists from Vilnius University and Kaunas University of Technology. "Both testing processes are combined in our system, whereby LaserVision Hence, it is based on know-how, which comes LED unites the advantages of both: from 50 years of experience in the electronics Phoseon Technology's huge step forward rapid testing with the camera and exact business and is also supported by the surpassing 5 W/cm² irradiance power opens new measurement with the spectrometer", theoretical knowledge from academia. applications and opportunities in disinfection explains Block. The unique feature is the matching. A board can be measured The BIOWN brand reflects the biological “This milestone development enables us to with the spectrometer and then brought needs, which are essential for every human. produce a level of irradiance that provides into agreement with the camera system. The created system, which is not only scientists, researchers and equipment Testing is done at the individual-LED energy-efficient, but also adopts the natural manufacturers the capability to think and act level. LED lights can be tested completely biorhythm, is maybe even more important beyond traditional methodologies,” says Jay as final products and also in different than practical visual demands. This is a Pasquantonio, Senior Product Manager at production levels. An additional new step in enhancing people's living and Phoseon. “For the past 30 years, low camera is optionally available for working environments. irradiance has limited the efficacy of UV-C testing ultra-bright LEDs. solutions. Phoseon has provided a new path Visual Function: The super smart six based on high power that allows our The LED ribbons are rewound onto a different light channel mixing technology customers to build high-performance; roll at the conclusion of testing. However, is one tool to enhance "Zeitgeber‘s". long-lasting products that reduce research subsequent cutting to a single roll ready Designed to improve the physiological times, lower operating costs and provide for sale can also be done. "LaserVision processes of adapting to prolonged improved disinfection capabilities.” LED acquires another unique feature presence under artificial lighting. with this additional option for testing BIOWN technology, provides light Phoseon’s SLM technology offers LED ribbons. management to keep the color rendering unmatched levels of deep UV irradiance, index Ra>95 and R9>90 in all CCT which enable significant process range 2700-6500 K. improvements in the field of Life Sciences, including faster analysis and operations, Selteka Introduces Automatically supports organic day light and increased capabilities for disinfection Skylighter Luminaires for color temperature and intensity rhythm, and decontamination applications that Biodynamic HCL responds to external lighting dynamics and require low wavelengths. the people in the room. On 18 March at the Light + Building 2018 High irradiance, combined with appropriate show in Frankfurt, Selteka will present Emotional and Biological Effects: wavelengths, targets specific bonds in DNA, Biodynamic, Enhanced Human Centric Extensive Melanopic Lux range and RNA and proteins within microorganisms and lighting luminaires Skylighter with BIOWN Flicker free in a range of up to 800 Hz. biomolecules. This allows shorter inactivation light mixing technology – amazing light Comfortable smart technology that enables times while improving overall efficacy of the spectrum and color rendition, automatic light people working/living for long periods of disinfection. The high absolute irradiance of intensity and color profiling which supports time without natural light to experience a these new solutions enable high-throughput natural human biorhythm. light source that allows them to live closer processes in pharmaceutical, sequencing, to their circadian rhythm. air handling and manufacturing facilities.

Fraunhofer IIS IoT-Bus: the terminal node is becoming more Data Manipulation Secure Communication High Security - Not Just and more important. The Internet of on the Internet of Energy Things (IoT) has specific requirements In the area of energy management a simple, for Lighting on data rate, range, reliability, cost, but secure and reliable interconnection of The Fraunhofer Institute for Integrated flexibility, interoperability, and in certain local resources, producers and consumers Circuits IIS is developing the IoT-Bus with cases, also data security. Consistency of through the decentralization of power generation IPv6 support and integrated security the protocols and seamless data-flow is becoming increasingly necessary. concept. It is a communication bus based across different domains is essential to Especially in cloud-based applications, on EIA/RS-485 and the IEEE 802.15.4 enable the IoT. Internet connectivity holds secure IP-based communication is required. standard, which enables a secure and security risks in manners of data It allows access via IP-capable control reliable data transmission of measured manipulation and cyber-attacks. devices such as smartphones, tablets or values and control commands and PCs for visualization or control purposes. connectivity to the Internet of Things. Fraunhofer IIS is developing a communication The IoT-Bus forms a cross-media bus that allows a direct connection of system communication protocol and unites the components on the Internet besides the local two worlds of WPAN and fieldbuses communication. The IoT-Bus reliable without complex protocol conversion. transmission at higher data rates and longer The novel technology IoT-Bus is developed distances is possible as what is offered by as part of the SEEDs project. conventional fieldbuses and wireless solutions. Through automatic address IP Communication on the assignment and allocation of the installation, Internet of Things While the Fraunhofer IIS IoT bus is not the process is facilitated. If a confidential In the context of the increasing cross- especially dedicated to lighting controls, or manipulation secure data connection linking and digitization in the fields of it offers huge opportunities to control LED is necessary, the IoT-Bus provides Industry 4.0, energy management and luminaires: Bridging distances up to 500 m standardized crypto-logical procedures with up to 1 MBit/s facility management, IP capability within for authentication and encryption.

Functionality They can simply communicate with the Applications: The IoT-Bus is a fieldbus with IPv6 support internet or be connected to the cloud. • Communication between local resources, and an integrated security concept. It producers, consumers, even over long combines the advantages of native internet Additionally, the IoT-Bus offers by its data distances protocol support with the advantages of a container concept, the possibility of a • Optimization of energy flow and energy fieldbus in terms of range, reliability, so-called »tunneling« of messages and management robustness and low latency. protocols, such as CAN message. This • Smart Building Automation functionality can be used for range extension • Communication for in-house Grid Control This technology is based on an adaptation of of limited itself fieldbuses. The tunneling of (DC and AC) the communication standard IEEE 802.15.4, CAN messages is currently taking place in • Direct connection of system components which is the de facto standard for Wireless the SEEDs project. to the Internet of Energy Personal Area Networks (WPAN) and sensor • Integration of smart meters (for local networks, thus allowing the use of these Contrary to wireless sensor networks and communication) wireline logs. The concept envisages a WPAN solutions, the IoT-Bus scores with • Connection of system components at the IoT communication on 2- or 4-wire lines. The higher reliability, robustness and greater 4-wire solution also enables the power range for point-to-point connections. Possible Fields of Application supply for communication of the Compared to common building automation CAN Range Extender communication nodes via the bus. communication technologies, it also offers With its data container concept it is possible real-time communication and additionally IP to transfer various protocols. This allows the The use and adaptation of IEEE Std. 802.15.4 capability and IT security for the IoT-Bus. IoT-Bus to be used as a range extender. the IoT-Bus allows a medium-border This function is already available for the CAN communication channel. For 802.15.4 nodes Unique Characteristics of the protocol. A packet filter can be used to select are realized without breaking protocol a Communication Bus: which messages are to be transferred from comprehensive communication network with • Connection with the wired and one CAN domain to another both wired IoT-Bus and wireless IEEE Std. wireless world Using a special access method allows the • IPv6-based fieldbus with cross- IoT-Bus for Industry 4.0 IoT-Bus a real-time communication. The media communication The IoT-Bus allows interdependent production serial interface uses the standard EIA-485 • Ideal combination of data rate and facilities to exchange information. Existing (RS-485), but can also be adapted to other range for IoT applications systems can be retrofitted to IP-capable to interfaces. • Data rate up to 1 Mbit / s with a range be used for industrial applications of up to 500 meters The system consists of up to three different • Real-time capability Building Automation physical communication paths, the actual • By deterministic bus access method Devices in the building automation system, IoT-Bus (1) based on the IEEE Std 802.15.4 • IPv6 capability of the end nodes such as blinds, radiators, air-conditioning with customized bus access method defined • IoT capability by supporting Internet and lighting can be easily connected with the by IEEE 802.15.4 radio nodes (2) can be standards (6LoWPAN, UDP, IPv6, etc.) IoT-Bus in larger complexes over long extended and a connection of the internet (3) • Consistency of the protocols distances. The communication for automated on the IoT-Bus router. • Direct compatibility with IEEE 802.15.4 and manual control is thus made possible based radio Easy and Flexible Integration of Standard • Enables the transmission of standardized Secure Lighting Control Protocols application protocols The IoT-Bus is suitable for individual lighting The IoT-Bus uses 6LoWPAN and thus • MQTT, MQTT-S, OPC-UA, CoAP control in modern buildings – e.g. "Light As A realizes the IPv6 capability of the terminal • Integrated Security concept Service" and "Human Centric Lighting" nodes. This allows that all protocols which • Use of standardized encryption are based on TCP/IP can be used methods (TLS, D-TLS) With its IP capability and real-time capability, conceptually. The end nodes can be, among • No additional gateway required the IoT-Bus is suitable for a wide range of other things, sensors, actuators or generally • Fast packet routing without applications within Industry 4.0, building »things« in the context »Internet of Things«. protocol conversion automation and energy management.

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Supercomputers Aid Discovery of New, Inexpensive Material to Make LEDs with Excellent Color Quality A team led by engineers at the University of California San Diego has used data mining and computational tools to discover a new phosphor material for white LEDs that is inexpensive and easy to make. Researchers built prototype white LED light bulbs using the new phosphor. The prototypes exhibited better color quality than many commercial LEDs currently on the market.

Under UV light, the phosphor emits either green-yellow or blue light depending on the chemical activator mixed in (Photo by David Baillot/ UC San Diego Jacobs School of Engineering)

Phosphors, which are substances that emit light, are one of the key ingredients to make white LEDs. They are crystalline powders that absorb energy from blue or near-UV light and emit light in the visible spectrum. The combination of the different colored light creates white light.

The phosphors used in many commercial white LEDs have several disadvantages, however. Many are made of rare-earth elements, which are expensive, and some are difficult to manufacture. They also produce LEDs with poor color quality.

Researchers at UC San Diego and Chonnam National University in Korea discovered and developed a new phosphor that avoids these issues. It is made mostly of earth-abundant elements (strontium, lithium, aluminum and oxygen); it can be made using industrial methods; and it produces LEDs that render colors more vividly and accurately.

The new phosphor, Sr₂LiAlO₄ or simply SLAO, was discovered using a systematic, high-throughput computational approach developed in the lab of Shyue Ping Ong, a nanoengineering professor at the UC San Diego Jacobs School of Engineering and lead principal investigator of the study. Ong’s team used supercomputers to predict SLAO, which is the first known material made of the elements strontium, lithium, aluminum and oxygen. Calculations also predicted this material would be stable and perform well as an LED phosphor. For example, it was predicted to absorb light in the near-UV and blue region and have high photoluminescence, which is the material’s ability to emit light when excited by a higher energy light source.

Researchers in the lab of Joanna McKittrick, National Science Foundation’s Extreme Acknowledgments: a materials science professor at the Jacobs Science and Engineering Discovery The press release was published from the School of Engineering, then figured out the Environment at the San Diego UCSD at http://jacobsschool.ucsd.edu/news/ recipe needed to make the new phosphor. Supercomputer Center. news_releases/release.sfe?id=2476 They also confirmed the phosphor’s predicted light absorption and emission In this study, Ong’s team first compiled a Researchers published the new phosphor on properties in the lab. list of the most frequently occurring elements February 19 in the journal Joule. in known phosphor materials. To the A team led by materials science professor researchers’ surprise, they found that there Paper title: “Mining Unexplored Chemistries Won Bin Im at Chonnam National University are no known materials containing a for Phosphors for High-Color-Quality in Korea optimized the phosphor recipe combination of strontium, lithium, White-Light-Emitting Diodes.” Authors of the for industrial manufacturing and built white aluminum and oxygen, which are four study are Zhenbin Wang*, Jungmin Ha*, LED prototypes with the new phosphor. common phosphor elements. Using a data Joanna McKittrick and Shyue Ping Ong at They evaluated the LEDs using the Color mining algorithm, they created new phosphor UC San Diego; and Yoon Hwa Kim* and Won Rendering Index (CRI), a scale that rates from candidates containing these elements Bin Im at Chonnam National University, 0 to 100 how accurate colors appear under a and performed a series of first-principles Republic of Korea. light source. Many commercial LEDs have calculations to predict which would perform CRI values at around 80. LEDs made with well as a phosphor. Out of 918 candidates, *These authors contributed equally to this work the new phosphor yielded CRI values SLAO emerged as the leading material. greater than 90. It was predicted to be stable and exhibit This work was supported by the National excellent photoluminescence properties. Science Foundation, Ceramics Program The computational quest for a new material: (grant 1411192). Computational resources Thanks to the computational approach “It’s not only remarkable that we were able to were provided by the Triton Shared developed by Ong’s team, discovery of predict a new phosphor compound, but one Computing Cluster at UC San Diego, the phosphor took just three months - that’s stable and can actually be synthesized the National Energy Research Scientific a short time frame compared to the years of in the lab,” said Zhenbin Wang, a Computing Centre, and the Extreme Science trial-and-error experiments it typically takes nanoengineering Ph.D. candidate in Ong’s and Engineering Discovery Environment to discover a new material. research group and co-first author of the supported by the National Science study. Foundation (grant ACI-1053575). “Calculations are quick, scalable and cheap. This work was also supported by the Basic Using computers, we can rapidly screen The phosphor’s main limitation is its less than Science Research Program through the thousands of materials and predict ideal quantum efficiency - how efficiently it National Research Foundation of Korea, candidates for new materials that have not converts incoming light to light of a different which is funded by the Ministry of Science yet been discovered,” Ong said. color - of about 32 percent. However, and ICT (NRF-2017R1A2B3011967). researchers note that it retains more than 88 Ong, who leads the Materials Virtual Lab and percent of its emission at typical LED is a faculty member in the Sustainable Power operating temperatures. In commercial LEDs, and Energy Center at UC San Diego, uses a there’s usually a tradeoff with color quality, combination of high-throughput calculations Ong noted. “But we want the best of both and machine learning to discover next- worlds. We have achieved excellent color generation materials for energy applications, quality. Now we are working on optimizing including batteries, fuel cells and LEDs. the material to improve quantum efficiency,” The calculations were performed using the Ong said.

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CIE RESEARCH COLOR QUALITY OF LIGHT 32 CIE Research Addressing Color Quality of Light Sources Related to Perception and Preference

With the development of new lighting technologies, LED light sources are increasingly used for general lighting. These light sources are creating diversity in light spectra and imposing new challenges in assessing their color quality. Youngshin Kwak, Director CIE Division 1, describes how several CIE Research Groups are joining forces, working on this topic to find new standard indices to adequately specify color quality.

The Color Rendering Index (CRI), Limitations of the CRI viewed, even though the chosen light in particular the general color Limitations of the CRI have been recently sources had lower Ra values (Figure 1). rendering index, Ra, defined by addressed, especially for solid-state light Due to the nature of the CRI (or a color CIE Publication 133, is widely used sources, whereby the Ra values do not fidelity index), many preferred lights with for assessing the color rendering always correlate well with visual evaluation increased gamut are excluded when a characteristics of light sources. by general users. This mismatch arises, minimum requirement is given, e.g. It was first published in 1965 after first, from inaccuracies of the CRI in its Ra ≥ 80 or Ra ≥ 90. fluorescent lamps had emerged, intended role as a color fidelity index; and and was last improved in 1974. second, from perception-related color Color science has progressed quality effects beyond color fidelity. The first Improvement Measures considerably since then, is the inaccuracy of color appearance It was determined by the CIE that, and recognized improvements evaluation arising from the original 1974 CRI for both aspects, better color quality are available for many of the formulae and the small number of color test characterization methods are needed to components used in the CRI. samples used in the CRI calculation. measure and specify white-light sources, Nevertheless, the CRI has served The second is a limitation of the CRI due and the work was divided into two fairly well for most light sources and to the fact that it is simply a color fidelity corresponding tasks: (1) to develop a has been well accepted over the metric; that is, the CRI values are based on scientifically accurate color fidelity index, past 40 years, though revision of the color appearance of objects compared assigned to TC 1-90, and (2) to develop one the CRI was occasionally investigated to their appearance under the defined or more perception-related color quality (CIE Publication 135/2-1999). reference illuminant. Color quality measures beyond fidelity, assigned to There are many government regulations characteristics other than color fidelity are TC 1-91 for initial work. and voluntary programs to promote also important, and different analysis energy efficient lighting products. methods are required to assess them in the In 2017, TC 1-90 published a Technical These regulations and specifications context of lighting applications, tasks, and Report ‘CIE 224:2017 CIE 2017 Color not only specify minimum luminous user preferences. This is especially Fidelity Index for accurate scientific use’ efficacy (lm/W) but also minimum important when samples undergo chroma describing a general color fidelity index, values of the general color rendering enhancements arising from the source’s Rf, as a scientifically accurate measure of index, Ra, and ranges of white light narrowband spectral features. In some color fidelity with respect to a reference chromaticity to ensure good color experiments, subjects generally preferred illuminant, although there still remain some quality as well as energy efficiency, illumination that slightly enhanced the color technical issues for further research. as both are inter-related. saturation of the illuminated objects they This color fidelity index, based on the fidelity

Figure 1: different regions of the world. Much more CRI measures color fidelity to a reference illuminant, research data are needed to be able to different from color develop an index for perception-based preference color quality. A whiteness index also needs to be investigated as a quality index to assess white lights, in order to resolve the problems associated with objects that contain optical brightening agents. Therefore, future research is required.

Key Research Questions Figure 2: • How can “preference” (or a model for Calculation flow for the color color quality perception) be clearly fidelity index defined and assessed for the intended end use? It may also be affected by users’ long term visual experience. How can it be addressed? • Are the individual variations in such preferences too large to define general preference? • Can the preference for chroma saturation and white light chromaticity be substantially different in different regions (or race of people) in the world? • What are the relevant parameters to measure the subjective aspects of color index of the Illuminating Engineering The CIE encourages further research quality and the whiteness index? Society of North America, defined in on these two aspects of color quality, • How to design an index to measure the TM-30-15, addresses aspects for only which may be useful inputs to the current whiteness perception of a light source? the first part of the limitations of the CRI – or future work of CIE. The overall objective How to apply the surface whiteness it does not address the need for perception- of the research is to develop indices for indices for lighting application? related color quality measure(s) beyond color quality other than color fidelity, fidelity (Figure 2). However, it does correct especially those related to general color several previously reported inaccuracies preference, which is the perceived or Conclusions of the CRI as a color fidelity measure. subjective judgement of color rendering Based on the research proposed here, The important improvements of this (e.g. for naturalness). It is known that CIE will define standard indices that measure, relative to the CRI, are the chroma saturation (gamut area) or shift of can be used with a color fidelity index, update of the color difference calculation, chromaticity from the Planckian locus has all of which will allow specifying or in particular the object color space, strong effects on perceived color rendering evaluating overall color quality of lighting and the incorporation of 99 test-color or preference, but such effects are not products. The CIE also recommends that samples which provide a more uniform measured with a color fidelity index, important lighting metrics such as the distribution of slope and curvature values and some preferred lights are penalized by Color Rendering Index require formal as a function of wavelength and which have a color fidelity index such as the general international agreement.New metrics color appearance values that are more color rendering index, Ra. It seems there introduced at the regional level could widely and uniformly distributed in the are general preferences in chroma cause confusion in the global lighting three dimensions of a uniform color space. saturation and chromaticity, but research market. The process of developing To assess the important aspects of the data for such perception effects are still CIE recommendations by scientific color qualities of light sources other than very limited. Data are lacking for various consensus often requires considerable color fidelity, in particular, those related conditions, e.g. different hues, different time. However, since the CIE is expediting to color preference, CIE TC 1-91 is objects viewed, different parameters the researches on color quality, developing a Technical Report on this (naturalness, preference), and long-term new CIE color quality metrics will be subject, which will be the groundwork for effects, in different applications, introduced in the near future. developing color preference metric(s). demographics (race, age, sex), or for

Tech-Talks BREGENZ - Fred Maxik, Founder & CTO, Lighting Science Group

Fred Maxik Mr. Maxik is one of the world’s foremost experts in Solid State Lighting. He is the founder and CTO of Lighting Science Group. He has over 25 years of experience in innovating environmentally friendly technologies. He is the principle inventor of more than 140 patents and has published several papers on light and its interaction with biological systems and has received several awards for his work.

LED light in combination with advanced controls, and here especially IoT capabilities, opened several new options in lighting. In this context, the term Human Centric Lighting, and more recently, the term Biologically Active Light have become trendy. Fred Maxik, founder and CTO of the Lighting Science Group, who held the keynote speech at LpS 2017, recognized these opportunities in a very early stage when most other manufacturers were still struggling with the challenges of the new technology. In the interview he explains what his perception of light is and its importance in our lives. He gives insights into his philosophy and ideas on which criteria artificial lighting has to fulfill in order to live up to the promising terms „Human Centric Lighting“ and „Biologically Active Light“.

LED professional: Thank you for joining us the planet. And all these already had some LED professional: So can we say that natural for this interview. We attended your Keynote photosensitivity, some diurnal period light is the standard and artificial light should yesterday and we were very impressed with associated with them. When you take a look be as close as possible to natural light? the talk, especially the fantastic pictures. at single cell algae today, we see a diurnal One of the main points of your keynote was period. When we look at what composes the Fred Maxik: Maybe. I think there are two the relationship between light and humans. human body there are a lot of the same components to light that we need to be For me, one aspect that stuck out was how ingredients. And the sun and daylight and all conscious of. We cannot deliver to a human you explained that light is as it is - and light have an influence, therefore, on our being inside a building the dose of light that humans, plants and animals all developed in biological processes. So that is where we the sun delivers. We are not capable of the a way where the light was right for them. establish that this is the evolutionary path we intensity of it, nor should we be. However, Could you explain that again for our readers? took. This is why we are using photosensitivity we can look to and create a portion of what in many ways – not just our circadian is natural. But first we must understand what Fred Maxik: Certainly. There is, I think, rhythms – but even the way we digest our portion of what is natural has the biological at this point, a general consensus that we food. The way bugs grow in our stomach. effects we’re interested in. And what portion are and have evolved as diurnal species. The way we see and the way we act. We’ve of what is natural does not? And therefore We’re used to the light cycle of the sunlight even had some seasonal effects that we’ve we can reengineer a spectrum of light with and the evening cycle of the stars and moon. seen in various cultures that were seen up to that knowledge to mimic what we want to And we did not just uniquely develop our a hundred years ago before electric light replicate in natural light. bodies’ processes. They were adopted – was introduced to their environments. in fact – infused as different bacteria, We’ve created eternal summer now with LED professional: From biology, especially as different cells, as different things our lighting systems and we all live in this from entomology, we know that you can combined to create life as we see it today on eternal summer. trigger a reaction easier by hyper optimal

All life on earth, including humans, have evolved under sunlight and are used to the light cycle and spectrum of sunlight. The visible part is just a small fraction of this spectrum. Most artificial light sources, including LEDs, don’t even roughly reproduce the visible spectrum of the sun

conditions than you could with the LED professional: Yesterday there what we consider our natural way to natural part. Do you think we should were a lot of lectures dealing with go to sleep, our natural hormone try to achieve this or do you think it human centric lighting. We have secretions at night, our natural REM might be stressful for people and we been talking about this topic and sleep cycles and not delaying the should stay within the limits given to its influence on human biology for onset of all those. I think that’s us by nature? at least fifteen years now. stable, sound science today. But everyone who talked about it There is sound science around how Fred Maxik: My personal belief is in their lecture acted as if it were light can wake us up in the morning, that I think it should be considered. completely new. Don’t we have how we can take that alerting dose. It should be studied and it should enough information right now to How we can work forward towards be understood as best we can. start with human centric lighting? mitigating some of the present And then with that knowledge and I ask because if you looked at Jan activities like seasonal affective that data we can make judgments Denneman’s timeline, yesterday, disorder. You’re right: those things as to what we should and shouldn’t human centric lighting starts far have been around for a while. do. In the very first instance, I think beyond the year 2020. Don’t we we should try to do no harm. have the technology or we don’t Now we understand the pathways have the knowledge to focus from the ganglion receptors in our The other thing I would say, on it right now? eyes that communicate into the and we talk about this quite suprachiasmatic nucleus in the frequently, is natural light versus Fred Maxik: Maybe we don’t have brain and I think we understand artificial light. I don’t know that a a receptive audience. I think that we how the circadian clock works. photon knows if the light is coming have enough knowledge today to There’s solid ground there. And I from the sun or a light bulb. I have a begin implementing some aspects don’t know if we have a receptive problem with natural and artificial. of human centric – or lighting that audience in the consumer base yet. Light is light. How it is produced can affects humans – particularly in the And that’s going to be a challenge. be discussed. I would probably alter areas of sleep. I think that’s the I actually agree with you. It may be that and say that natural light is the most compelling argument we have several more years before the spectrum of light and the intensity today. We have good laboratory audience is educated enough to of light we evolve from. We evolve studies by first class universities understand what we’re talking from the sun and the stars and that show elements of our light; about. But as an industry we can then there is “other” light. The other particularly that peak at around discuss it and promote it. A serious conversation light is introduced by man initiated 475 – 485 nanometers, can disturb between the two actions. And I would add that that a healthful sleep. So I think that we Secondly, though, as we look at lighting professionals, Fred Maxik and spectrum is not the same and in can begin today on developing light the light centricity of humans and Guenther Sejkora no cases is it yet the same. sources that are less interruptive to other things, there are going to be

other things we continue to sent to universities around the world We’ve brought in interns from all discover. There is some work being to work on this lighting type science over the world to help us discover done on light and chemotherapy. that we aptly named ourselves after. things in-house as well. I think we’re There haven’t been any studies And then we started getting into frugal in our testing but I think we’ve yet but it’s very promising. other areas like the mosquito – got enough latitude to be able to put But it will probably take years, one of the deadliest animals on the enough stakes in the ground so that maybe decades, to sort out. planet. What do we know about the we can have a study here that might There’s light and aging and brain spectrum that would let us create take five to ten years to mature and health. Particularly dementia and lights that are less attractive to we have a study that might mature Alzheimer’s as we look at how the them? What would let us create in six months. It’s a good mix. brain clears various waste matter. lights that are more attractive to This is very, very promising work them so that we can move them into LED professional: How big is going forward. As an industry, trap areas? What can we do about Lighting Science Group and how we should look at what this means - other animals? many people deal with science and we call it the human centricity of research and how many deal with light. That’s a wonderful opportunity We continued down that path for a the products? for the industry and it’s a wonderful long time and now we’re looking at opportunity to do some real good health and sanitation. We’re looking Fred Maxik: There are about with it – and there are a dozen at how we clean our air with light twelve to fifteen that work directly categories like this. and how we clean our water with on the R&D side and of those, light. How we develop a built-in probably about three or four are LED professional: There are a environment that’s in a healthful university professors who come in few companies already using place – not only to work, but also and consult with us for periods of this knowledge. For example, to live. Now we’ve split the company time. In terms of the company itself: the Lighting Science Group is into two parts: One concentrating The company is not very large. It’s working on the interaction of light on general end products – probably about $70 to $75 million a and humans. Could you give us a doing some millions of dollars a year right now – so fairly small for a short introduction to the Lighting month in general lighting products, lighting company but I think we’re Science Group? and the other looking on science. on the right track and if we are, Trying to figure out ‘What are the we’ll see a very nice organic Fred Maxik: Sure. I established next steps?’ ‘What are the products growth shortly. Lighting Science Group eighteen that flow from there?’ and ‘What is years ago. It was established only the continued research that we want LED professional: If we look at to look into solid-state light. We had to do to advance into those areas?’ your products on the Internet, no other interest in other sources. the main product seems to be the It wasn’t only about energy – LED professional: It would be replacement bulb with a very initially it was about how we take nice to know more about light and specific spectrum. Do you have light and how we might manipulate humans, but it seems there is not other products as well? that spectrum of light to create enough money for research. How do different effects. And as we learned you finance your scientific work? Fred Maxik: We do everything from more about it – about fourteen years highly dynamic 16-channel color ago – we started working with Fred Maxik: Today we are privately mixing test devices for universities NASA. We worked with the financed. We do work with a private all the way to a single fixed astronaut corps and began to Equity Company in New York that spectrum. So we have what I think understand what the challenges funds our efforts. They have been a is the full gambit of what is possible. were in space. They started talking wonderful partner for us. We started We’re working on hyper spectral to us about how every 90 minutes with them almost eight years ago sources that will be controllable in having a space station circling the and they have financed our a number of ways. We’re also Earth and all the lighting cues for the activities. They are equally curious looking at potentially hyper spectral astronauts are thrown off. So very about where this will go to and are sources even in a bulb that will quickly, they start losing team firm believers that we are building be adjustable. I think those are coherence because their clocks are value by discovering new pathways soon to come. essentially free running - out of and have allowed us a lot of latitude sync. So we started to develop in how we continue to move this LED professional: If someone lighting systems for them to test forward. But we also partner with decides to buy a product that which were beginning to be installed universities to create extensibility in should have certain spectrum a decade later on the space stations. the studies we do. We partner with effects, do you get feedback from medical schools and overseas those people about how it works? We developed technologies from universities as well. We try to make there. We made test beds that we ourselves as extensible as possible. Fred Maxik: In a lot of cases we do.

Closer to sunlight - in comparison to conventional phosphor converted white LEDs (b), the latest generation of LEDs almost perfectly matches the visible spectrum of the sun (a)

We get a lot of direct feedback and also have instructions about how to the light bulb, they would give their for the most part it’s very positive. use light? customer a 15% better sleep, People from around the world and tell them why they’re doing it – actually reach out to us to ask Fred Maxik: Yes! We are beginning then everybody who stays in the where they can buy products. to develop this idea – and it doesn’t hotel, comes away thinking about it. We get calls from all around the need to be prescriptive – but in the So because the hospitality sector is world and the feedback is generally sense of the studies we’ve done, we in the business of selling sleep, very positive. And just to repeat a know that if we give the wrong light I think they would help us. There’s a little anecdote I used in my speech 90 minutes before sleep, we delay natural synergy there. So that would yesterday; there’s a value the the onset of sleep, then we delay probably be my first target. lighting industry leaves on the table the onset of REM sleep, then we because we don’t understand the delay the onset of melatonin LED professional: If we go back customer we’re serving yet. In North secretion. We’ve seen this in to the technology and what your America and the United States – studies. So we have the knowledge company is doing for lamps or the sleeping aid industry is larger today to start building those leaflets. systems: How do you shape this than the entire lighting industry. If we spectrum? Do you do your own can displace a small fraction of that LED professional: I talked to Jan material research to find the right industry using warm light instead of Dennemann earlier and we agreed phosphors? Or do you work with sleeping aids, we could double the that the consumer needs to be partners? size of the light industry. So when educated. If the end-user is you think about what lighting can educated and wants the better light Fred Maxik: It’s a combination. be, instead of having the “others” then it would put pressure on the We do our own material research. come in and try to take our business companies that install the lights to We do our own material research where our profitability is. Instead of provide the higher quality light. with converters. We do our own sharing our data with the CISCO’s of But how can we do this? material research with filters. the world, and whoever else might We don’t do research on dye – want to market our data – what if we Fred Maxik: Actually, I do have an we source our dye. And we mix all decided, instead, to take a little idea. I think there is a natural first those technologies together. piece of their business? I think there customer. The natural first customer We have a very senior chemist in is the opportunity like never before for all of this is hospitality. Hospitality the group that was involved in for the industry to grow in a very pays 500 Euros for curtains and LEDs very early on in the industry. unique way. 100 Euros for a pillow; a thousand We have two physicists, and we Euros for a bed and then tells its spend a lot of time optically LED professional: That is an customers that they can offer them modeling our sources and what interesting comparison between the a better night’s sleep. But then they we’re getting and how we’re getting lighting and sleeping aid industries. pay 1 Euro for the light bulb they put it. We don’t make our own Normally, if you buy a sleeping aid – next to the bed! If we can educate phosphors today. If we want them, there is a package leaflet that tells the hospitality sector and show we have them made or we source you exactly how to use it. Do you them that if they paid 15 Euros for them ultimately for production.

But we do experiment both in the quantum whether it’s being used effectively or whether studying UV how much harm short dot space or in the filter space to see how it’s being used happily. And I think, as we wavelength light can do. So there’s no precise we can get to, what we think is our start gathering this data and mixing it with reason, until we hit a certain threshold that ideal spectrum output. the lighting recipes we are applying, we, as a we shouldn’t expect there’s the potential for machine become much smarter as to what short wavelength damage. But we go LED professional: Another question about we do and how we learn and how our lights outside and sit in the sun and get a technology: If you need light in your learn. I think there may be some very simple monstrously high dose of blue light and bedroom, for example, I think it could be a metrics that we can apply today into a we’ve done that for years. In fact, since luminaire or a lamp with a fixed spectrum. lighting system or a lighting fixture, that we’ve been here. So I think that we can But if you need one for your office, I think it allows to understand how the people are overstate the case. And I’m concerned that has to be dynamic because you stay in the utilizing that light and that space. And I think we push it now. I think that blue light at the office the whole day and as natural light that’s an area worthy of lots of exploration in wrong time of day is more of a concern, like changes during the day, I think the indoor the future. That’s again – a high value path. a late night dose of blue light. Our visual light should change as well. So, do you also We’re looking at office space now – system is very quick to respond but has a work in the controls field or do you adopt open office space – shared desks. There will very short latency. It responds in seconds controls that are already known or control be ways of identifying user patterns. There but there is no latency to that effect residually systems that are already on the market? will be ways of identifying utilization patterns is seen. This blue system – these ganglion that I think lighting is uniquely positioned to receptors that we have – having much longer Fred Maxik: Again the answer is both. But explore. And that’s an area that I think is well latency of their effect – and once they are I’m a bit cynical about standard controls and worth for the lighting industry to pursue. triggered and once they start signaling, the standard smart-type applications. I’m latency of their effect can go on for one or actually spending my time creating and LED professional: At the controls and driver two hours, maybe even three hours. And looking at machine learning systems. level, it’s not just the spectrum itself, you said that’s what we should be cautious about. It’s Whereas the fixture or the fitting or the light you could imagine that people are more alert not that it’s doing physical harm to the eye, source understands where it is in the world when they are relaxed but we still have an although it can if you stare at it for long and how it is being utilized without being told issue with many drivers today and that is enough, but it’s throwing off these other what to do. So – maybe a slight dithering of flicker. There are big discussions going on physiological systems. To me, that’s where the spectrum through the day, light cloud about what is acceptable and what isn’t. the danger lies. It’s not just something we cover would do. But not necessarily big What is your opinion? pass and we see lights going on. But once transitions for sunrise and sunsets. I think the ganglion receptors are triggered, the those are more for show than for real effect. Fred Maxik: There are many people looking latency of that interrupts our sleep. I think So – I don’t know. I think the jury’s still out on at that today. We have folks on staff that are there will be studies in the future that will whether we can use a fixed spectrum in the looking at it and exploring it, and also people show that what we’ve done to ourselves is at office. I think that some compromised on some of the committees that are least partially responsible for causing spectrum that has enough enriched blue, investigating. This is where it goes back to hormonal cancers and a contributor to early enough of a high CRI and can be reduced to what’s natural. Natural light doesn’t flicker. onset dementia. And these are the areas a fairly low glare level that mimics a natural It shifts, but it doesn’t flicker. I think the that, I think, it’s going to take ten and twenty light without having to worry about having to closer we can mimic that in a light source, year studies to get to. But I think we will link shift it to anything else other than that. the more interesting it becomes and the these together in the next ten to twenty I think the slight dithering would reduce the less obtrusive it becomes to human health. years. eyestrains and the other things associated So I’m a firm believer that we should with that. But I think that jury’s out. I think minimize it but I’m not on top of the LED professional: That is a very interesting that we don’t understand that, yet. specification associated with doing that and thought-provoking statement to close today. I’m more interested in how we morph on! Thank you very much for your time. LED professional: That partially answers my color without having sophisticated controls. next question: If you use standard systems Fred Maxik: Thank you. who makes sure that the programs in these LED professional: Back to the biological systems are right? You can have the best effects. There was a discussion yesterday light source, you can have the best controls, about the blue ray. Professor Haim talked but if it’s programmed wrong it won’t do its job. about the damage that shifting the day/night cycle – which can actually be done using Fred Maxik: This is where, again I think that blue light – might do, or does. So what do we, as an industry, have an amazing ability to you think about this? In my opinion the gather data that will enhance our value or we SCHEER report only looks at the damage decide to give it away to someone else. It is that blue light can do to the eyes. But what known in building systems – it is known in do you think about the influence of blue or the architectural space - these patterns of short wavelength light on the whole body. utilization of space can be used to create – and analytics can be applied to that – Fred Maxik: High energy – short wavelength to understand how space is used and light can certainly harm things. We know by

The lifetime of an LED system is usually specified by the LM-80 report using the TM-21 method. Unfortunately, this value is solely valid for one specific application. Sebastian Haemmerle and Thomas Schmitt from the University of Applied Sciences Vorarlberg developed a new open-source Modelica library for dynamic simulation of LEDs: The DynaLed library. The aim of the work was to evaluate the lifetime and the corresponding economic efficiency of LEDs in dynamic operation by means of the LM-80 report and according to the TM-21 calculation method. Furthermore, it should be possible to use the library for component dimensioning, e.g. the heatsink. The primary task was to develop simulation models that can be parameterized with manufacturer information, e.g. the datasheet, but still provide sufficient accuracy. As an application example an LED louvre luminaire (Article Code: 29001077) from LEDON Lamp GmbH was simulated utilizing the developed library. At the end, results from the lifetime- and the economic efficiency simulation were discussed.

LED lighting is about to replace luminous flux by 30%. In further described properly. Ageing, i.e. all conventional lighting consequence the specified the decline of luminous flux for technologies, e.g. incandescent lifetime will be used to calculate different operating cycles, e.g. lamps or fluorescent lamps. the economic efficiency of a full load, office or industry has This revolution of the lighting lighting installation to compare to be modeled. Finally, by industry was triggered by the the costs and benefits of the utilizing the results from the rapid development of LEDs investment. ageing model the economic due to their luminous efficacy, efficiency has to be calculated. lifetime and costs. However, this practice raises a number of delicate questions, In the following paragraphs, The lifetime of an LED system is particularly with regard to the current situation and then specified by the manufacturer. comparability and accuracy: a new modeling approach are In general, this value is based briefly described and the on the LM-80 report [I] and is • How to compare two lighting models of the Modelica library calculated using the TM-21 products with different lifetime DynaLed are introduced. method [II]. The result is information. After explaining how a transferred to the manufacturer's • What is the lifetime if a simulation has to be set-up, datasheet. Unfortunately, dynamic operating cycle is an application example is this value is solely valid for one used? shown and the simulation specific application. Moreover, • What is the lifetime if a results are discussed. At the this application is not regulated dynamic ambient temperature end the most important results by law and can be defined by is given? will be summarized. the manufacturer. A common application is, for example, To answer these questions to use an ambient temperature sufficiently accurate, an LED of 25°C, a continuous full load model has to meet the following operation and a specified requirements: The electric- and maximum allowed decline of thermal behavior has to be

Figure 1: Simulation approach

Status Quo of Simulation & The existing thermal simulation and or with parameters that can be Improvement Options calculation methods range from very measured easily by the user. Most of the diode models that simple lumped models (usually can be found in literature are based electric equivalent circuit, i.e. Cauer on ideal models [3] or are described and/or Foster networks) to complex Modeling Approach by means of the Shockley equation CFD-analysis (Computational Fluid The basic concept of the modeling [4]. Both models are used to Dynamics) [10, 11]. In combination approach is shown in figure 1 investigate the switching behavior with the electric diode model whereas ideal models are usually lumped thermal models are used. Basically, the simulation approach preferred to enhance the simulation can be separated into two main performance, i.e. fast dynamics of Up to now, there is no standardized parts. The first part describes the the real behavior are neglected. calculation model that describes the input for the simulation model. However, none of these models ageing effects of an LED [12]. Thereby, it is important that all consider losses (conduction-, However, the IES (Illuminating required input can be provided turn-on- and reverse-recovery Engineering Society) developed a easily by the user. losses). In order to consider losses, simulation approach to predict the several approaches exist that lifetime of the LED, called the These inputs are: either extend the ideal models or TM-21 method. • Datasheet of the LED: has to be introduce models that utilize provided by the LED-chip characteristic curves specified in A lot of luminaire manufacturers manufacturer and includes the manufacturer's datasheet. provide economic efficiency information about the maximum The latter ones are so-called simulation tools on their websites, ratings and the characteristic behavioral models [5, 6]. The e.g. [13, 14]. Another approach to values simulation platform PLECS, for calculate the energy efficiency of • LM-80 Report of the LED: has to instance, provides behavioral a lighting system is the lighting be provided by the LED-chip models to take the diode losses energy numeric indicator (LENI). manufacturer and includes into account [7]. However, The standard EN 15193 describes measurement data of the lumen considering an LED, one part of how the LENI value can be maintenance and the chromaticity the electric power is irreversibly calculated or measured. The limits for a minimum of 6000 hours converted into heat (i.e. losses) of these concepts are reached if the • Operating Cycle: must be while the other part generates the simulation type is changed from provided by the user and gives luminous flux. Consequently, steady state to dynamic. information about the operating the luminous flux cannot be time and operating mode of the neglected. Some examples of LED Since currently no model is available LED in each time step models are given in [8] for the in the literature that describes an • Other Information: must be simulation software SPICE or in [9] LED sufficiently accurate, this work specified by the user and provides for the Simscape environment. is intended to develop a dynamic information about the Both implementations are based model of an LED that can be used environment, the system and the on the Shockley diode model. for lifetime simulations and economic costs The disadvantage of these models efficiency calculations of dynamic is that not all parameters are operating cycles. Furthermore, The second part of the simulation provided in the LED datasheet the model can be parameterized approach describes the which makes them quite hard with parameters specified in the implementation of the models to use. datasheet and in the LM-80 report in Modelica.

Figure 2: Package structure of systems in the concept stage of the the library development as well as for products that are already on the market.

Simulation Library The structure of the DynaLed library for lifetime- and economic efficiency simulation of LED systems is depicted in figure 2.

A short description of each package is given in the list below: • Icons: Includes all icons of the This part consists of the Both parts present their own models provided within the library following models: challenge concerning the • Bus: Contains all variables of • Electrical LED model: implementation. On the one hand interest. Adapters are used to parametrizable with the the input should be modeled in a write signals on the bus and information from the LED user-friendly way and on the other read signals from the bus datasheet hand the simulation environment • System: Consists of the • Thermal model: parametrizable should have a high degree of template of the entire system with the information from the LED flexibility with regard to different LED and the data record for the datasheet and user information systems. By contrast the difficulty of model parameterization about the heatsink the implementation of the test • User Inputs: Includes a model • Ageing model: parametrizable environment is to achieve a balance for the operating cycle and a with the LM-80 Report and between the computation time, model for “other information” calculated with the output from complexity and accuracy of each e.g. the ambient temperature the electrical and thermal model part of the simulation environment. • Components: This package • Economic efficiency model: includes the models and its parametrizable with 'other In addition, all implemented blocks accompanying sub models information' and calculated with should serve as a basic library for for the LED, the heatsink, the output from the ageing model dynamic lifetime simulations and the lifetime- and economic profitability assessments of LED efficiency calculation

Figure 3: Top level of the entire model

Figure 4: The implementation of the entire Signal flow of the LED system is similar to the simulation model approach and is illustrated in figure 3. It consists of five main parts: the user inputs, the luminaire model, the ageing model, the maximum ratings and the economic efficiency model. Additionally, the luminaire model is split into an LED model and a heatsink model. This design is chosen because each model can be replaced individually, leading to a high degree of flexibility. Figure 5: Top level of the LED For the data transmission between model the different modules a bus is used. To clearly represent which signal is written to the bus and which is read from the bus, adapters are designed. Therefore, for every signal on the bus a writing adapter and a Figure 6: reading adapter is created. Implementation of the electrical power model

User inputs and data supply The required user inputs are separated by the source of origin, i.e. datasheet, LM-80 report, operating cycle and 'other information'. Furthermore, the entire data supply of the models in the DynaLed library is done via the data record, shown in the middle of figure 3. A record is a collection of the model parameters. To parameterize the entire system model shown in figure 3 the record is instantiated and the parameters are propagated to each model.

Figure 6 shows the entire electrical of the normalized operating cycle Luminaire model power model of the LED. On the top, and the nominal forward current of The luminaire model is separated the electric circuit is modeled the LED. Therefore, the output into an electric model and a consisting of the ballast and an LED. current is adjusted depending on thermal model. On the bottom, the power the operating cycle. consumption calculation of the system with the unit Ws is Additionally, the following Electric model implemented. Since the electric assumptions for the model of the An LED is a special kind of diode. circuit is solely modeled for a single ballast were made: The difference to a regular diode is LED, the measured power • It is an ideal ballast, i.e. its that the LED model is a combination consumption is scaled with the efficiency is 100% of an electric power model, a number of LEDs in the luminaire. • The lumen output of the LED is photometrical power model and a The output of the model is the linearly depending on the current thermal power model. The forward current and the power of input schematic signal flows are shown in the electric circuit. figure 4. The electrical properties of an LED The ballast is required for the power are equal to the electrical properties The top level of the LED model is supply of the LED. The ballast is of a diode, i.e. to simulate an LED implemented according to figure 4 modeled using an ideal current the diode model will be used. There and is shown in figure 5. source that is driven by the product are mainly three different techniques

Figure 7: Implementation of The photometric power model is the LED also a static behavioral model, see figure 8. The forward current of the LED is the input for the table containing the relative luminous flux characteristic curve of the LED that is specified in the datasheet. The output of the table is the current depending relative luminous flux. Additionally, the luminous flux depends on the junction temperature. To take this into account the relative luminous flux drop depending on the junction temperature is multiplied with the relative luminous flux. To get the absolute value of the luminous flux the relative luminous flux depending on the junction temperature and the forward current is multiplied with the reference Figure 8: Implementation of the luminous flux value. photometric power model The next step is to calculate the luminous efficacy of the LED. Therefore, the ratio of luminous flux and electrical power is computed. Based on this and the maximum possible luminous efficacy [III] depending on the spectral emission the photometric output power is calculated which represents the output of the model.

According to the principle of conservation of energy the thermal power is the subtraction of the photometric power from the electric power. This calculation is done in the thermal power model shown in figure 5. to model a diode: ideal modeling, forward characteristic curve of the physical modeling and behavioral LED specified in the datasheet. modeling. The ideal model has The output of the table is the current Thermal model the disadvantage of precision; depending forward voltage drop. The thermal model is implemented drawbacks of the physical model Additionally, the forward voltage as a Cauer-network. The losses are the parameterization and the depends on the junction temperature. from the thermal power model of simulation performance. Therefore, This dependency can be found in the LED are the source of heat flow the most suitable modeling the datasheet as well. To take this entering at the junction interface. technique is behavioral modeling, into account, the percentage voltage The heat is transported through because it can be parameterized drop depending on the junction the thermal resistance from the with parameters and characteristic temperature at a reference forward junction to the solder point to the curves from the datasheet and the current is multiplied with the forward heatsink and to the atmosphere. results are usually accurate enough voltage (refer to EQ1). This voltage is The temperature profile of the to get an understanding of the real the input to the signal controlled ambient temperature is specified behavior of the system. voltage source. in the “other information” model shown in figure 3.

The LED model is shown in figure 7. ∆Vƒ (Tj ) EQ1 The current sensor measures the Vƒ (Iƒ ,T j ) = Vƒ (Iƒ) ∙ 1+ Additionally, the dynamics of the Vƒ ( reƒ ) input current of the LED, which is thermal model are implemented the input for the table containing the using the heat capacitors of the

Figure 9: different elements. All the heat Implementation of the capacitors have to be initialized thermal model with the ambient temperature because it is assumed that the system has been in its ambient state long enough so that it has adopted this temperature level.

The implementation is shown in figure 9. The output of the thermal model is the solder point temperature of the LED.

The values for the thermal resistances and the heat capacitors can be taken from the corresponding datasheets and are calculated with the geometrical boundary conditions and material or have to be evaluated via For the ageing model the influential constant α are stored in a table and temperature measurements. factors temperature and current are dependent on the inputs. are the only being considered, because in comparison radiation The result of EQ3 is the lifetime Ageing model and light have a relatively small of the system depending on the The ageing and therefore the lifetime impact on the lifetime of an LED. forward current of the LED, of an LED-system depends on a The other three factors are the solder point temperature and multitude of influential factors. influenced by the end user and the specified L value. Due to the can therefore not be considered fact that the forward current and The most important factors in a meaningful way. solder point temperature changes are listed below: dynamically the percentage ageing • Temperature: the heat which is The ageing model is based on is integrated over time. Therefore, produced from losses of the LED the TM-21 calculation method the result of the ageing model is the has negative effects on several that is based on the exponential percentage ageing of the system LED parameters, e.g. the lifetime, decay (EQ2). after the reviewed simulation period. the luminous flux, etc -αt • Current: each LED is driven φt = B ∙ e EQ2 with a certain electrical current. Maximum ratings The amplitude of this current Where t is the operating time in The task of this model, shown in has a direct effect on its lifetime. hours, Φ the averaged normalized figure 3, is to monitor the maximum The lower the current, the lower luminous flux output, B the ratings. For a reliable long-term the heat generation and the projected initial constant derived operation of the LED it is important higher the lifetime by a least squares curve-fit and α, that these values are not exceeded. • Radiation and light: the light the decay rate constant derived by that is emitted by the LED has a least squares curve-fit as well. The following values are an ageing effect, for example, monitored: on the housing or the reflector After reformulating EQ2 to EQ3, • Operating temperature • Mechanical forces: the reason the time to reach a specific Lx value • Junction temperature for applying a mechanical force [IV] can be calculated [2]. • Solder point temperature can be a faulty assembly, • Forward current ln (B/x) high temperature fluctuations, etc. TLx = EQ3 The effect is a premature failure α If one of these values exceeds of the LED the permitted range the simulation • Humidity: can lead to corrosion EQ 3 is implemented in the is terminated. of metal parts inside the LED- ageing model depicted in figure 10. module and therefore to a The inputs are on the one hand the premature failure forward current from the electric Economic efficiency model • Chemicals: chemical substances, model and on the other hand the For a meaningful simulation of the like high sulfur dioxide content of solder point temperature from the economic efficiency the several the air, have a negative effect on thermal model. The actual values aspects of a lighting system have the lifetime of the LED [16] for the start value B and the decay to be addressed.

Figure 10: Implementation of the ageing model

Aspects to being addressed: E This can be done because the a model underlies following • Investment IE = ∙ N ∙ IkWh ∙ t EQ6 • Energy procurement costs η assumptions: • Lighting hours • Plant lifespan If a luminaire comes to the end • The operating cycles are repeated • Nominal lifetime of the of its lifetime it has to be replaced, every 24 hours lighting system i.e. a new luminaire has to be • The ageing model does not • Installed power including all installed. Therefore, each consider the calendrical ageing, auxiliary units, e.g. ballasts replacement means that an i.e. the ageing is solely depending

• Maintenance costs investment in the amount of II has on the solder point temperature to be arranged. The number of and the forward current of The economic efficiency model replacements is dependent on the LED

evaluates the total investment Itot of a the period under review t and the lighting system over a specified lifetime of the system tend. After executing the function for

period of time. The total investment The replacement costs IR can lifetime calculation the results are can be computed with EQ4. It is be computed with EQ7. used to parameterize the economic

the sum of the initial investment II efficiency model. Afterwards, t for the luminaires including the I = 1+ − 1 the function for economic efficiency R ( ) EQ7 ballast and the installation, tend calculation is called.

the energy costs IE for the review period and the replacement costs Running a Simulation The output contains the

IR for the luminaires. To keep the application of the following results: DynaLed library as simple as • Total investment for the

Itot = II + IE + IR EQ4 possible two functions have reviewed lifespan been created: One for the lifetime, • Initial investment for the luminaires

The initial investment II consists of the other for the economic and the installation cost

the costs for a luminaire IL including efficiency calculation. • Energy costs for the the ballast and the installation reviewed lifespan

costs per luminaire IIn. This value The function for the lifetime • Number of required replacements is multiplied by the number of calculation simulates the entire of the luminaires installed devices N (EQ 5). system model from figure 3 for a period of 24 hours, i.e. I = (I + I )∙ N EQ5 I L ln the stop time of the simulation Application Example

The energy costs IE are the is 86,400 seconds. Depending An application example, which is product of the average energy on the behavior of the system in this available on the market, is used to

consumption Ea of the luminaire period all values are extrapolated. show the function of the DynaLed including the efficiency η of the For example, in order to compute library in a real system. The LED ballast, the number of installed the entire lifetime of the LED, System is simulated utilizing the

devices N, the electricity costs IkWh the output of the ageing model, developed Modelica library and the and the time period under review t. i.e. the ageing after 24 hours, economic efficiency of different The calculation is done with EQ6. is extrapolated. operating cycles are compared.

Table 1: System It must be noted that according to Operating Lifetime Power [W/ Results of the lifetime The simulated luminaire is an LED the limits of the TM-21 calculation Cycle [h] Luminaire] simulation louvre luminaire (Article Code: method, only the lifetime of the full 29001077 - for more information load and the constant light output FL 45,564 40.13 refer to [17]). The light sources of operating cycle are within the the luminaire are 104 pieces DURIS boundaries. To verify the lifetime of CO 56,518 35.83 E5 LED from Osram (Type: all operating cycles an LM-80 report GW JDSRS1.EC-FUGQ-5L7N-L1N2). is required with a testing period of ED 155,119 19.83 The power supply of the LED is a 26000 hours. The simulation shows constant current ballast. that the lifetime of the system is HC 92,475 23.09 strongly dependent on the used OF 109,362 22.84 The following three different types operating cycle. are available: SR 138,086 14.50 • Ballast DALI dimmable For further consideration the values • Ballast DALI dimmable from table 1 are not adjusted and IN 73,921 31.73 • Ballast 1-10V dimmable are directly used to parameterize the economic efficiency calculation. Table 2: The used ballast type depends Luminaire Installation Energy Required parameters on the application and in further Operating [EUR/ [EUR/ [EUR/ for this example consequence on the operating cycle. Economic Efficiency Cycle Luminaire] Luminaire] kWh] Calculation Results FL 120 25 0.15 For the economic efficiency Results calculation a simulation period of CO 170 25 0.15 The results are separated into lifetime 100,000 hours was assumed. calculation results and economic The purchase price of a luminaire ED 200 50 0.15 efficiency calculation results. including the ballast, the installation HC 200 50 0.15 costs and the energy costs are required. These costs depend on a OF 200 50 0.15 Lifetime Calculation Results variety of different factors. The lifetime of the system depends, SR 200 50 0.15 on the one hand, on the forward Some costs factors: IN 200 50 0.15 current and on the other hand, • Purchase price of a luminaire on the solder point temperature of including the ballast the LED. Therefore, the lifetime of °° Depends on the used ballast. According to the multitude of the system varies, depending on the The non-dimmable ballast is influencing factors there are no used operating cycle (OC). For the cheaper than the ballast with generally valid values for the simulation seven different operating constant light output. required parameters. The used cycles are considered. Five of them The ballast with constant light parameters are listed in table 2. are appointed to different areas of output is cheaper than the DALI application and are translated from dimmable ballast. The result is The results of the economic the human centric lighting curves that depending on the operating efficiency calculation are the total from [18]. Additionally, a full load cycle a suitable driver needs to investment Itot, the initial investment operating cycle and a constant light be selected which has an II, the energy costs IE and the output are added. influence on the price number of replacements NR, see °° Depends on the discount level table 3. The following different operating of the customer cycles are used for the simulation: • Installation costs • Full load (FL) °° Depends on the ballast used. Interpretation • Constant light output (CO) The luminaire with the DALI The influence of different operating • Education (ED) dimmable ballast results in cycles on the lifetime of an LED • Health and care (HC) additional installation effort, e.g. luminaire and in further • Office (OF) more wires, sensors, consequence for the total costs are • Shop and retail (SR) programming, etc. depicted in table 1 and table 3. • Industry (IN) °° Depends on the hourly labor costs of the installer One illustration is the following: The average power of the system • Energy costs the lifetime of the luminaire also depends on the operating cycle. °° Depends on the contract with increases by a factor 3.4 if the the energy provider education operating cycle is used The results of the different °° Depends on the cost increase instead of the full load one. The full simulation runs are listed in table 1. over the period under review load operating cycle has the

Table 3: Conclusion Results of the Operating Cycle Itot [EUR] II [EUR] IE [EUR] NR economic efficiency The developed library is a calculation FL 27,594 3,625 16,719 2 convenient tool for manufacturers for lifetime and economic efficiency CO 24,679 4,875 15,929 1 simulations of LED systems. The implementation provides a ED 14,416 6,250 8,166 0 simple and time saving method for any kind of adaptions. It allows the HC 22,125 6,250 9,625 1 user to simulate and compare different kinds of luminaires with OF 15,750 6,250 9,500 0 the same library. Furthermore, the handling of the library and the SR 14,416 6,250 8,166 0 data supply is implemented in a user-friendly fashion. IN 25,708 6,250 13,208 1

advantage of a 42% lower initial cost, is an increase of the total costs by because a non-dimmable driver can 91 % if an economic efficiency be used and no additional installation calculation for a review time period effort is required, the disadvantage of 100,000 hours is done.

Notes: [I] A record of the lumen maintenance, the chromaticity and the catastrophic failures of LEDs. This test will be done at three LED case temperatures (55°C, 85°C and one selected by the manufacturer). The minimum testing period is 6000 hours, whereby the data collection has to be done every 1000 hours. The LM-80 report is provided by every renowned manufacturer. For further information refer to [1] [II] The TM-21 specifies how to extrapolate the LM-80 lumen maintenance data to times beyond the LM-80 test time [2]. The disadvantage is that this model is only valid for steady-state applications [III] The calculation of the maximum luminous efficacy depending on the spectral emission is based on [15]. For the calculation the spectral emission of the LED and the photopic sensitivity curve of the human eye is required [IV] The Lx value describes the reduction in luminous flux. Whereby, x provides the information about the minimum level of acceptable lumen output in percent [V] For a sample size of 20 units, the maximum projection is 6 times the test duration of the LM-80 report [1]

References: [1] E. Richman. The elusive ‘life’ of leds: How tm-21 contributes to the solution. LEDs Magazine, 6, 2011 [2] M. Scholdt. Temperaturbasierte Methoden zur Bestimmung der Lebensdauer und Stabilisierung von LEDs im System. 2013 [3] M. Otter, H. Elmqvist, and S. E. Mattsson. Hybrid Modeling in Modelica based on the Synchronous Data Flow Principle. 1999 [4] S. O. Kasap. The pn Junction: The Shockley Model. 2001 [5] A. Wintricht. Verhaltensmodellierung von Leistungshalbleitern für den rechnergestützten Entwurf leistungselektronischer Schaltungen. 1996 [6] P. Denz, T. Schmitt, and M. Andres. Behavioral Modeling of Power Semiconductors in Modelica. 2014 [7] A. Courtay. MAST power diode and thyristor models including automatic parameter extraction. 1995 [8] D. Madur, N. Ghatte, V. Pereira, and T. Surwadkar. Modelling light emitting diode using spice. 2013 [9] MathWorks. Documentation: Light-Emitting Diode. www.mathworks.com, Accessed 2017 [10] Cree. Thermal Management of Cree® XLamp® LEDs. www.cree.com, Accessed 2017 [11] Vossloh-Schwabe. Thermal Design of LED Luminaires. www.vs-lighting-solutions.com, Accessed 2017 [12] C. C. Karl. Einfluss von Wasserstoff auf das Alterungsverhalten von InGaAlP Leuchtdioden. 2014 [13] LED Blog. Stromrechner für LED Lampen. www.leds-blog.de, Accessed 2017 [14] Lichtspur. Wirtschaftlichkeitrechner. www.light-trail.com, Accessed 2017 [15] W. Thomas and Jr. Murphy. Maximum Spectral Luminous Efficacy of White Light. 2013 [16] Osram. Zuverlässigkeit und Lebensdauer von LEDs. 2008. [17] LEDON Lamp Gmbh. Impressum. www.ledon-lamp.com, Accessed 2017 [18] Trilux. HCL-Kurven. www.trilux.com, Accessed 2017

RESEARCH FULL-COLOR NANOWIRE LEDS 50 Full-Color InGaN/AlGaN Nanowire LEDs for SSL and Displays

III-nitride based nanowire light-emitting diodes (LEDs) have received a staggering response as a future candidate for solid-state lighting and full-color displays due to their unique and exceptional features including drastically reduced polarization fields, dislocation densities as well as the associated quantum confined Stark effect (QCSE) on account of their effective strain relaxation. Moab Rajan Philip and his supervisor Dr. Hieu P Nguyen in the Nano-Optoelectronic Materials and Devices Laboratory at the New Jersey Institute of Technology (NJIT) present astonishing ideas to fabricate and control the color emission of III-nitride nanowire LEDs via molecular beam epitaxy (MBE) growth techniques. The advantage of such LEDs and their characteristics is also discussed.

High brightness LEDs are Introduction enhancement in the carrier already penetrating the market GaN-based nanowire confinement and reduced and replacing conventional heterostructures have been sought nonradiative surface recombination, incandescent light sources and out in recent times for their potential thus resulting in an overall boosting being utilized in areas of general to generate emission wavelengths of the carrier injection into the lighting, traffic lights, display varying from ultraviolet to near- active region of the LED device. applications and automotive infrared regions, which in turn, In the afore-mentioned context, lighting. The scope and need gives the lighting industry additional a unique core–shell nanowire LED for color-tunable novel high flexibility to develop phosphor-free heterostructure was introduced by efficiency LEDs has never been white LEDs. The latter mentioned utilizing self-organized InGaN/AlGaN the same. Engineering these phosphor-free nanowire white LEDs heterostructure. Such LED materials has been constrained has been shown to have tremendous structures offers significantly due to several fundamental potential because of their higher improved carrier injection efficiency limitations, including lattice efficiency, longer lifetime, and better and output power, in comparison to mismatch and the limitation of light quality in contrast to existing the typical InGaN/GaN nanowire bandgap engineered materials. phosphor-based lighting LEDs. By altering the size and/or In this regard, III-nitride technologies. Phosphor-free white composition of the InGaN active nanowire structures give LEDs have been envisioned region in the core–shell nanowire flexibility to this problem with in recent times by means of axial LED arrays during the epitaxial the ability to generate high or radially aligned bottom-up growth of nanowire LEDs, quality tunable color emission nanowire heterostructures including the device light emission properties, without much effort in contrast dot/disk/well-in-a-wire or core–shell including the correlated color to the conventional thin-film structures. Their device performance, temperature (CCT) and color structures. In this paper, however, is severely constrained rendering index (CRI) can be readily the ability of the III-nitride because of nonradiative surface modified. The electroluminescence nanowires LEDs for color tuning recombination. The large surface (EL) spectra show a very broad via MBE and the fabrication of recombination is reflected from the spectral linewidth and fully cover phosphor-free white LEDs using very short carrier lifetime (0.3 ns) the entire visible spectrum. this comprehensive approach values reported for conventional The fabricated InGaN/AlGaN LEDs along with the characterization nanowire structures. The use of exhibit excellent current–voltage of the fabricated LEDs will AlGaN shell in InGaN/(Al)GaN characteristics. The phosphor-free be illustrated. core–shell LEDs leads to an InGaN/AlGaN nanowire white LEDs

Figures 1a&b: A 45-degree tilted SEM image (a) of the InGaN/ AlGaN core–shell nanowire LED grown by MBE. Normalized room temperature photoluminescence spectra (b) depicting multiple emission colors from different InGaN/AlGaN nanowire LEDs [1]

display high CRI up to ~98, The nanowire diameter and density to red color in the visible regime which is more efficient compared can be tuned by varying the of the electromagnetic spectrum to the current phosphor-based white substrate temperature and/or In/Ga viz towards a higher wavelength LED technologies. Moreover, we flux ratios, whereas the nanowire was obtained by altering the In have successfully fabricated length can be controlled by the composition from a lower value phosphor-free nanowire LEDs onto growth duration. The 45-degree to a higher value. The latter metal substrates via a substrate tilted SEM image (Figure 1a) shows engineered heterostructures are transferring process. Compared to uniform nanowires with high areal being used to realize multiple color conventional nanowire LEDs on Si, density of ~1 x 1010cm-2. During the devices as expected. nanowire LEDs on copper (Cu) growth process of AlGaN barrier, exhibit several advantages, an AlGaN downward-bending shell Furthermore, the core–shell LED including more efficient thermal layer was also formed around the samples have an enhanced optical management and enhanced light InGaN layers due to the diffusion- intensity (a factor of >8 times higher extraction efficiency due to the controlled growth process [1, 2]. of photoluminescence intensity) in usage of metal-reflector and highly These core-shell structures exhibit contrast to the conventional InGaN/ thermally conductive metal substrates. low nonradiative surface GaN device. This has been linked to The LED on Cu, therefore, recombination, and improved carrier the fact that radiative recombination has stronger photoluminescence, injection efficiency compared to is more assertive on account of the electroluminescence intensities InGaN/GaN nanowire LEDs without effective carrier confinement in the and better current-voltage using core-shell structures. active region of InGaN/AlGaN characteristics compared to the LEDs, being more efficient when conventional nanowire LED on Si, compared to that of InGaN/GaN paving the way for a whole new Results and Discussion LED devoid of AlGaN core–shell generation optoelectronic device The emission wavelengths can be structures. This enhancement is for the future solid-state lighting, readily engineered across the entire associated to the strong carrier flexible displays and wearable visible wavelength regime thus confinement, due to the effective electronic applications. easily generating the full color lateral confinement offered by the spectrum. The optical properties of large bandgap AlGaN barrier and InGaN/AlGaN LED nanowire drastically reduced nonradiative Device Structure heterostructures (Figure 1b) revealed surface recombination. In addition, The InGaN/AlGaN LED nanowire that peak emission wavelengths of the core-shell InGaN/AlGaN LEDs heterostructures, were spontaneously InGaN/AlGaN core–shell nanowire boasts of significantly improved grown on n-type Si substrates under LEDs ranging from 460 to 670 nm carrier lifetime, which is more than nitrogen rich conditions by a can be attained. The effective 15 times higher when compared to radiofrequency plasma-assisted variation of the In composition in the the conventional InGaN/GaN LEDs. nitrogen source equipped Veeco active region of the InGaN active The latter improved carrier lifetime Gen II MBE system. Silicon and region was achieved by controlling stems from the reduced nonradiative magnesium were used as n- and the growth temperatures and/or surface recombination arising due to p-type dopants for GaN nanowires, In/Ga flux ratios. The longer the effective lateral confinement respectively. The LED active region wavelength like red light is often offered by the higher bandgap of consists of ten vertically aligned linked with a lower bandgap AlGaN shell layer in the core-shell InGaN dots, sandwiched between material for the active region. Thus, LED structure. 3 nm AlGaN barrier layers. the desired color emission from blue

Figures 2a&b: Electroluminescence spectra of various InGaN/AlGaN LEDs (a) with distinct emission colors, along with their optical image. Electroluminescence spectra of the phosphor-free core– shell nanowire white- LED (b) under injection current along with the optical image of the white LED [1]

Figures 3a&b: Electroluminescence spectra of phosphor- free white LED (a) and CIE 1931 chromaticity diagram (b) illustrating the emission characteristics of the same InGaN/AlGaN nanowire LEDs [1, 3]

The electroluminescence (EL) stable and nearly independent figure 3b. The fabricated white spectra and the optical image of of injection currents [2]. LED exhibits broad spectra with LED devices (Figure 2a) generated a fullwidth of half maximum of multiple color emission with peak The CRI of phosphor-free white ~171 nm and offers SPD values wavelengths ranging from 475 to LEDs can be engineered by in the range of 410–800 nm, 650 nm within the InGaN/AlGaN controlling the In composition in the respectively. The resulted CRI LEDs, thus reaffirming the multiple InGaN active region, thus leading to values of around ~98 were color photoluminescence spectra. various emission spectra and measured for those phosphor-free Multiple color emissions were different spectral power distribution nanowire LEDs. combined within InGaN active (SPD) characteristics. In contrast region of a single AlGaN nanowire to conventional planar LEDs, III-nitride nanowire LEDs are device, leading to a strong and InGaN/AlGaN core–shell nanowire normally grown on Si substrates, high-quality phosphor-free white LEDs offer a unique feature of which may largely absorb photon light emission, evident from optical providing flexibility in engineering emitted from the LED active region, micrograph image (Figure 2b) [1, 3]. the peak emission wavelengths and severely limiting the light output The EL spectra of phosphor-free spectral linewidths, which in turn are power. Moreover, Si semiconductor LEDs were measured under 1% duty the two most vital criteria for CCT generally exhibits low electrical cycle pulsed biasing conditions and CRI. The EL spectra with conductivity and thermal expansion (to minimize junction heating effect) injection currents varying from coefficients compared to metal presented an emission spectrum 50 mA to 250 mA for phosphor-free substrate. High power LED with very broad spectral linewidth of white LEDs is provided in figure 3a applications, however, require large- more than 150 nm, fully spanning while the Commission Internationale area device size and operate at high the entire visible spectrum regime. de l’Elcairage (CIE) coordinates for injection current which mostly will Moreover, the spectra are highly the same LED device is depicted in heat up the devices. The resulted

RESEARCH FULL-COLOR NANOWIRE LEDS 54

Figures 4a&b: Current−voltage (a) and light output power (b) vs injection current characteristics of the conventional nanowire LED on the Si substrate and nanowire LED on metal Cu substrate [4]

quantum efficiencies, output power usage of metal-reflector and Conclusion and lifetime reduce rapidly when the highly thermally conductive metal In conclusion, high performance junction temperature increases. substrates. The LED on Cu, therefore, InGaN/AlGaN core-shell nanowire Therefore, managing heat dissipation has stronger photoluminescence, LEDs on Si and metal substrates should be seriously considered. electroluminescence intensities and have been developed. The color Besides the applications in solid- better current-voltage characteristics properties of such full-color state lighting illumination, the use compared to the conventional nanowire LEDs can be adjusted by of LEDs in telecommunications, nanowire LED on Si. The LEDs on controlling the indium composition and decoration displays for flexible Cu substrate exhibit excellent in the InGaN/AlGaN active region of electronics devices has also been current-voltage characteristics and the LED structures. This study intensively developed due to the show lower leakage current and addressed some major roadblocks feasible integration of such LEDs in slightly higher current in forward for the practical applications of these electronic devices. In this bias, compared to the LED device nanowire-based LEDs and has regard, we have successfully on Si substrate at the same voltage, further provided an entirely new fabricated full-color and phosphor- shown in figure 4a. The optical avenue for the development of free white LEDs on Cu substrates. image of light emission from the LED future high efficiency phosphor-free Nanowire LED structures were first device on Cu substrate is presented white LEDs as well as full-color grown on silicon-on-insulator (SOI) in the inset of Figure 4a. Illustrated in LEDs with tunable emission for substrates by MBE, then were Figure 4b, the nanowire LED on Cu advanced lighting applications. transferred onto Cu substrates via shows higher light output power the substrate-transfer process. compared to that of nanowire LED Compared to conventional nanowire on Si [4]. The enhanced output power LEDs on Si, nanowire LEDs on Cu is attributed to the enhanced light exhibit offer more efficient thermal extraction efficiency and better heat management and enhanced light management in LED on Cu substrates extraction efficiency due to the which was explained previously.

References: [1] M. R. Philip, D. D. Choudhary, M. Djavid, M. N. Bhuyian, J. Piao, T. T. Pham, et al., "Controlling color emission of InGaN/AlGaN nanowire light-emitting diodes grown by molecular beam epitaxy," Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, vol. 35, p. 02B108, 2017 [2] H. P. T. Nguyen, M. Djavid, S. Y. Woo, X. Liu, A. T. Connie, S. Sadaf, et al., "Engineering the Carrier Dynamics of InGaN Nanowire White Light-Emitting Diodes by Distributed p-AlGaN Electron Blocking Layers," Scientific Reports, vol. 5, p. 7744, 2015 [3] M. R. Philip, D. D. Choudhary, M. Djavid, K. Q. Le, J. Piao, and H. P. T. Nguyen, "High efficiency green/yellow and red InGaN/AlGaN nanowire light-emitting diodes grown by molecular beam epitaxy," Journal of Science: Advanced Materials and Devices, vol. 2, pp. 150-155, 2017 [4] M. Rajan Philip, D. D. Choudhary, M. Djavid, M. N. Bhuyian, T. H. Q. Bui, D. Misra, et al., "Fabrication of Phosphor-Free III-Nitride Nanowire Light-Emitting Diodes on Metal Substrates for Flexible Photonics," ACS Omega, vol. 2, pp. 5708-5714, 2017

EVENTS LED FORUM 2018 - HCL IN PRACTICE 56 Technology Is the Answer, But What Was the Question?

In cooperation with the Lucerne University of Applied Sciences and Arts, Electrosuisse held the LED Forum 2018, which focused on “Human Centric Lighting in Practice”. Arno Grabher-Meyer from LED professional was invited to attend the first class one-day event, held at the end of January for the DACH (Germany, Austria and Switzerland) region at the Basel Congress Center.

Prof. Bjoern Schrader from of several years, the whole the target groups: To get an the University of Lucerne aptly community is now facing all the overview or to learn about more entitled his short opening pros and cons of the IT and specific hot topics or to raise speech “Technology Is the semiconductor businesses; awareness for the situation in Answer, But What Was the especially the extremely short general. To fulfill this goal, Question?” This headline life cycles of only a few months. the event started and ended perfectly describes the current New products and technology with a joint session. The topics situation of lighting planners changes must be continuously in the main event were, and electro planners. monitored and are dictating Lighting Technologies & IoT, Product managers, developers daily business. Keeping track, Light Planning, Street- and of lighting applications and the at this lightning pace, is a Outdoor Lighting, Planning and rest of the audience have surely challenge. And finding the right Installation of LED Lighting Sets also recognized the truth of that technology for the application is were held in four parallel tracks. title in their businesses. even more challenging. So it is not surprising that the original In the following report, Arno Everyone that is involved in the question might fade away and Grabher-Meyer communicates lighting business has had to one may lose their orientation his impressions of the event and With a total of over accept that with the introduction and focus. summarizes the lessons learned 600 participants, of LEDs the digital era began. from the Lighting Technology the organizer’s expectations were Not being a part of a slowly The aim of this well-structured and IoT track. clearly surpassed changing world with life cycles event was to give assistance to

The Opening Session and Keynote Speeches Prof. Schrader outlined the status quo and revealed the true problems of the lighting community. He pointed out that the LED hype caused a lot of rumors and discussions about technology and that a lot of information about the technology is now available. Unfortunately, there isn’t a lot of useful information available about opportunities and how to apply it correctly. Prof. Schrader identified “HIB” as the most important element of the future of lighting. HIB is the combination of HCL (Human Centric Lighting), IoT (Internet of Things), and BIM (Building Information Management).

In the opening session Prof. Mathias Wambsganss, Prof. Tran Quoc Khanh und Sabine De Schutter natural sunlight. Prof. Wambsganss good vision. He is convinced that In an animated warmed up the audience for the demonstrated that lighting is not a true human centric lighting also has lecture, Prof. Dr. Khanh introduced conference topics and the four luminaire, but lighting has to be to consider these facts. Street the audience to the sessions. While presenting very treated as a complex system lighting projects for public spaces is physiological aspects different aspects, the speakers all consisting of many elements and it one example of when these facts of vision and the seemed to agree when they pointed needs to be managed as a project. need to be taken into account. relation between age and visual capabilities out the importance of “good light” for humans. They demonstrated that Prof. Tran Quoc Khanh presented In the last key note speech a lot has changed and that lighting his findings about the demographic Sabine De Schutter explained the designers, meanwhile, have to have transition in visual behavior and the possibilities of triggering impulses a much broader understanding than consequences for future lighting for cities with lighting workshops. in the pre-LED era. Knowledge technologies. He argued the People in general don’t really know about HCL, IoT and BIM is now importance of this topic by showing much about light and especially not required. More than ever before, the transitions in the age pyramid about good lighting. Most of them an interdisciplinary education is until 2050 and the accident statistics don’t even recognize that it’s light necessary to give lighting designers that show an over-proportional that they are missing in their cities: the necessary tools. amount of older people being Good, correctly applied and affected. Light and visual attractive light! She learned about Prof. Wambsganss questioned capabilities are recognized as being light and lighting design at the end how the term HCL is often used. one important reason for this. of her academic training to become He proposed to talk about Prof Khanh explained this an architect by accident. The idea integrative lighting in accordance to conjuncture with biological facts. fascinated her from the beginning CIE DIS 017:2016, 17-29-030 to With increasing age, opacification of and she recognized the dilemma better express that visual and the eye dramatically increases and and decided to improve the non-visual effects are included. the number of axons decreases by situation. Her idea: Organizing He emphasized the updated DIN about 25%. In addition, the relative lighting workshops and festivals. specifications, DIN SPEC 67600 and amount of needed light to maintain a She explained the goals and the DIN SPEC 5031-100 that consider similar contrast, hence object success of these activities using the current knowledge about ipRGC differentiation, increases by a factor the example of the “Tartu in Lights” and their importance for sub- of two. Glare sensitivity of the visual festival in Estonia. The objective of conscious non-image-forming system of older people is also the lighting design workshops were functions that are important for our significantly increased. Among other to be an experimentation ground for normal biological activities and factors, this all asks for measures lighting in the public realm which health. He criticized that with the - sometimes apparently conflicting aims to investigate and improve the “LED hype” and the energy saving measures: While blue light especially city’s current urban lighting and to trend one important element of HCL causes opacification of the lens, create real size prototypes for is not adequately recognized; more blue light is necessary for citizens and visitors to experience.

Sabine De Schutter demonstrated how The second element of this concept, From the Four more complicated and limited. lighting events and the modern lighting master planning, Parallel Sessions Such a solution needs two workshops can give demonstrates that planning modern After one and an half hours of addresses/devices, it cannot be momentum to improve public lighting requires a holistic interesting keynote speeches that controlled by a broadcast, cannot light quality in cities and revitalize urban life approach that deals with the many really concerned everybody, be color calibrated, and dimming, complex aspects involved and that the audience had the choice while maintaining a specific color lighting is not only a matter of safety, between the above-mentioned point, is not possible. DT8 devices security and mobility, but serves as specialty sessions before the are still rarities on the market, a tool for creating identity and livable closing session brought all the but they need just one address, cities. The “Interactive light” participants together again. understand a broadcast, can be workshop helped people to learn While the other three sessions calibrated and both CCT and that one can do much more with would certainly have also been brightness can be controlled light than just switching it on and off. worth discussing, the following without interfering with each other. Light can also be interactive and can only summarize what was This means brightness stays stable responsive to various actions, like presented during the “Lighting when the CCT is changed and proximity, temperature, touch and Technology and IoT” session - vice versa. much more. The so-called “Guerilla chaired by Michael Meesters. Action & Workshop” might be one of Horst Rudolph, Director of Research the most important activities. It is an Marc Fontanive, project leader and and Lighting Technologies at open source idea for creating electrical engineer at Buehler & TRILUX, titled his lecture “Future- magical moments of quality lighting Schreder, explained what look out and Digital Lighting”. He described that demonstrates the power of light for when controlling a tunable white the current situation as follows: to transform spaces. Furthermore, system with DALI. Right at the For the last 10 years, efficiency was guerrilla lighting is a “war” on bad beginning he cleared up a common the major argument, light quality has lighting, but most of all, it is about misunderstanding. Controlling been ignored, and it is, unfortunately, having fun and raising the tunable white lights has nothing to still just “nice to have”. He identified awareness of the power of light. do with using DALI2, as DALI2 is self-configuration technologies as While the low financial support for related to the controller only. key elements for future lighting the first event of this kind in Tartu But the key lies in the operating systems. Mr. Rudolph also was a huge challenge, the success device, and here, the devices, emphasized that the step from a was more than remarkable, type 6 (DT6) and type 8 (DT8), product to a system that leads to a especially because while the light of have to be distinguished. Basically, disruption on the market is not just Tartu2016 has faded it will light up tunable white systems may also be an engineering task, but needs the city again in autumn 2018. realized with the older DT6. But it is appropriate lighting design.

While often the support for additional sensors is a major argument for IoT based lighting, he explained that sensors that are necessary for smart lighting and HCL can already provide interesting additional information. On top of the to-do list for HCL products is ease of use and the individualization of HCL systems. He emphasized the cultural difference between the USA, Asia and Europe in respect to lighting preferences and use as well as the regional differences that make individual solutions necessary. For him, individualization could also mean that one has his own unique profile always with oneself, maybe stored on a mobile device. This profile could then be applied to lighting systems all over the world; not just at home but also in the office, in a hotel, and so on. Horst Rudolph pointed security and commissioning level He talked about “Added Value due out the return of the In the talk “Internet Protocol (IP) between the IEEE MAC layer and to IoT: From Light to a Smart Button. industry to focusing based Lighting – Sense or the application layer. To do this job, The Suisse Post AG currently on light quality after Nonsense?” Volker Barth addressed it does not require any new manages 1.8 million square meters a decade of mainly targeting energy IoT in general and especially in hardware. Another advantage is that of illuminated spaces with a efficiency IPv6 based networks which he for existing building management significant energy consumption that recognized as being key elements systems the option of connecting create enormous costs. Using the for the future of lighting and many with a gateway is still a possibility. example of the Haerkingen site, other applications. Volker Barth, Thread gives you the freedom to he showed how IoT and LED lighting from Tridonic, who started his choose different solutions. could improve a business and career as an electrician before he reduce costs. He demonstrated continued with his advanced Beat Haenni is the leader of the several IoT implementations. Volker Barth explained how modern lighting education to become an industrial department for environmental Replacing an already comparatively fits in the future IoT engineer, knows what he is talking management at the Suisse Post AG. efficient lighting solution led to a ecosystem about as he also knows about the issues of planning electrical installations. For him, the network is the basis of the whole system and with its simplicity or complexity the chances to succeed rise or fall. He explained several application examples and finally proposed “Thread” to be used as a universal network protocol in future applications. While having some similarities to BT, Thread combines the best of different worlds. One of the biggest advantages of Thread based nodes is that they can be implemented in any IP network as an end-to end solution without the use of gateways, making a properly designed system less vulnerable. Within the local network, every node is part of a mesh network, connected with a standard router to the internet. Thread manages the

several interesting questions. The most important insights from the discussion were:

• HCL, IoT and other new technologies are badly needed for Europe’s lighting industry. Otherwise the companies are just in a price war with products from the Far East that they cannot win • User and user acceptance of these new technologies has to have focus and, to obtain this acceptance, information and education is inevitable • The lighting companies cannot completely carry out the education of the public. They may educate electro planners, but the end user education and information has to be accomplished by others, maybe new players Andreas Steiner explained the surprisingly high reduction in energy precisely when needed and not in a • Other success factors are, complexity of advanced usage. While the estimations regular cycle whether it’s needed or at first, the adherence of the HCL systems with predicted 50-60%, the measured not. This dramatically reduces the users’ privacy, simplicity of use, a graph that had a reduction on site is proven to man-hours of the service team. and clear perceptibility of an striking resemblance to a subway map exceed 80%. But another value Overhead costs could be reduced added value for the user was generated with the application with IoT. Recently the company also of IoT that the company did not think started a study on the efficient about at first. New ideas are employment and productivity The Closing -Seeing continuously coming up. Simple IoT improvements of the staff pertaining Beyond the Own Nose Gerry Hofstetter, push buttons for different devices to the implementation of new The closing session started with an orator with an were installed all over the site. technologies including IoT and HCL. Osram Lighting Services Ltd. CEO, incredible history, With these buttons the users can Andreas Steiner’s topic “Advanced delivered an unforgettable closing activate a service request for the Before the common closing session, HCL – Digital Concepts in Practice”. speech device. A service will be provided a podium discussion addressed He emphasized that lighting cannot easily be divided into separate areas and much less be reduced on illumination. He identified four connected areas: Lighting, sensing, visualization, and therapy. His company is working on solutions in all of these fields. He explained the importance of illumination and the chances for the lighting industry in one example: As it becomes more and more necessary to offer incentives for getting young talents for a company, feel-good factors, like a pleasant atmosphere, are getting more important, and lighting is a relevant part of that. He also gave practical examples where HCL and IoT were combined to providing additional value and he pointed out that there are many ideas and use cases that cannot be predicted from the lighting industry but that are addressed by potential

users: For example, a lounge chair great efforts at the most remote primarily on planners and lighting including HCL that is controlled by areas of the world to perform designers. It didn’t really address the vital data of the user. The idea spectacular projections and to engineers that design LED modules, was generated by the German document them with impressive luminaires or drivers. Nevertheless, police due to the space restrictions videos and photos. His story and it could also be a good idea for the in their offices. Mr. Steiner also career and the presented video was latter to attend such events from demonstrated how the nursing effort very impressive and left nobody time to time because it brings in dementia patients can be reduced untouched. This showed that he got technicians closer to the application using the new technologies. it right: Light touches, and light is and can lead to fruitful discussions what makes the picture that tells between the two worlds. The final highlight was Gerry more than a thousand words! Hofstetter’s talk “Light - Communicates, Inspires and Touches” with a video about his Final Thoughts artistic projecting ventures. While the final video really did steal Gerry Hofstetter is known as the the show, it also demonstrated the man who projected the Swiss Cross power of light. Keeping this in mind on the Matterhorn. But this is just is important, and the same message one of dozens of projects around was also part of the program in one the world. He and his team take way or another. The event focused

Iceberg in the Arctic. Illuminated by Light Artist Gerry Hofstetter (Image: ©Gerry Hofstetter)

With the evolution of LED lighting, one topic has come more and more in the focus of the lighting industry: Human Centric Lighting (HCL). While HCL is not clearly defined, a common understanding is that this is light and lighting that supports health and the well-being of humans. Some new proposals are going beyond the approach of providing just visible light in adequate quality, but also to providing invisible radiation, UV and/or NIR that support health and well-being. Some research and the evolution of humans show clear evidence for positive effects of this kind of illumination. Scott Zimmerman, CEO at Silas, presents a new approach that adds NIR radiation to LED illumination. He explains the background of this idea, how it also improves the quality of visible light and discusses the health benefits.

For millions of years the sun has In a very short evolutionary groups have migrated from their provided approximately 90% of time frame (200 years) we have evolutionary regions. This raises its energy in Near Infrared (NIR) moved from a predominately several key issues associated and Visible (VIS) wavelengths agrarian society where we with what is the optimum HCL with the remaining percentage spent 90% of our time in the baseline or even if there is just being roughly divided between sun to the present where we one HCL baseline for everyone. ultraviolet (UV) and mid/long spend 90% of our time under infrared (IR). artificial lighting (EPA estimate). As shown in Figure 1, In that same time frame, ethnic the lighting community is in the process of radically Figure 1: The lighting community narrowing the spectral is in the process of range of our artificial lighting radically narrowing environment compared to what the spectral range of our cells have evolved under. our artificial lighting environment compared This change has been driven to what our cells have by cost, technology, and energy evolved under (Credits: savings but appears to not be Nick Spiker, www. supported by any health or nikespiker.com) wellness benefits.

What HCL Baseline VIS About the Definition of Light Should We Use? Our visual system is limited to a While light is strictly defined as The spectral reduction from the range between about a little below those wavelengths to which our full spectrum of sunlight started 400 nm up to around 700 nm. eyes respond, in the author’s 150 years ago with filament sources This visible radiation is commonly opinion this definition is in part which provided copious amounts called light, and the lighting industry responsible for us missing the of NIR/IR but very little UV/blue is mostly focusing on it. This is importance of UV/NIR/IR to our cells content needed for melatonin characterized by the trend to offer and HCL. For the purpose of this stimulation. Fortunately, light sources that only provide this paper light will be used to refer to through most of this timeframe “just visible spectrum” (JV lights). UV/VIS/NIR/IR radiation. we were a substantially agrarian This radiation range, especially the society with significant time in the highly energetic blue range, is also sun. Over the last 40 years we have relevant for our photopic circadian Proposed HCL Baseline begun to shift to “Just Visible” (JV) cues. The blue range also affects Three basic tenets are proposed lighting via fluorescent but with still our physiology and it may cause for the HCL baseline: significant NIR/IR from incandescent some damage in tissues. • Minimum NIR/VIS ratio of light sources in our homes. In the greater than 1 last 10 years we have begun a • Zero flicker process that eliminates virtually NIR • Lighting should adapt to skin all NIR/IR sources from our The majority of the energy from the pigmentation levels artificial lighting environment. sun our bodies absorb is in the NIR. This unfortunately coincides with In this spectral region, melanin levels In general, the common sense energy saving NIR reflecting are dropping logarithmically allowing argument is that nature is window treatments and skin for penetration depths in excess of opportunistic and that over millions cancer concerns reducing our 1 inch into our body even through of years our cells have evolved to time outdoors. As shown by the our skulls. Independent from their take advantage of the 60% of the UV/VIS/NIR/IR pictures our bodies color, most organic materials spectral energy our eyes don’t see. absorb and react very differently (leaves, fabrics, and colorants) are This argument is further justified by to each spectral region. almost equally transparent to NIR, daylighting studies [1] indicating that respectively absorbing or scattering sunlight is always superior both NIR, as shown in Figure 2. short term and long term to our UV existing artificial lights. Even further, UV spectral regions provide energy the medical community is publishing for Vitamin D production. On the IR over 400 peer reviewed papers per other hand, highly energetic UV About 8% of the energy from year on NIR treatments [2, 3, 4]. radiation UV can harm our tissues, the sun falls in the IR spectral Ironically, at the same time, the destroy our genetic information, and region. This region is dominated lighting community is eliminating a cause cancer. Melanin is the by water absorption as melanin major source of NIR/IR from our dominate absorber providing absorption approaches zero. lives, the medical community is protection against UV ionizing In the IR we are all created equal discovering that NIR can be used to radiation and its associated skin (dark skin and white hair). treat everything from dementia to cancer. - Fair skinned individuals While controversial and beyond wrinkles. Sports teams are even with low melanin levels are 10 times the scope of this article, there is using NIR treatments to increase more likely to develop skin cancer even evidence that both athletic performance [5] with than dark skinned individuals. NIR and IR are fundamental to concern that its use should be energy storage in the body. banned from competitive sports [6].

Figure 2: The pictures demonstrate the differences in absorption and reflection of visible (VIS) radiation (left) and near infrared (NIR) radiation (right). - For comparison reasons both images are held in gray scales

Figure 3: The UV, VIS, NIR About flicker pictures show the Flicker is harmful and may even differences in eye be a factor in rising dementia rates. absorption. The sclera While probably the most (white of the eye) strongly reflects VIS controversial tenet, flicker does light but is 4 times not occur in nature and only more transmissive exists to simplify drive electronics. to NIR Credits: Nick Recent work at MIT indicates Spiker, www.nikespiker. com) - For comparison that pulsed light impacts plaque reasons the images are formation as it relates to dementia unified to gray scales [11]. It is also generally accepted that a significant percentage of the ASD population is sensitive to flicker [12].

Light and skin pigmentation Prior to recent migrations, skin pigmentation evolved solely based on latitude and foliage conditions. As shown in Figure 4, this evolutionary adaptation leads to Figure 4: Lambda Research huge differences in how NIR light is TracePro model of the absorbed in the human body. It is differences how NIR doubtful that a single optimum HCL light is absorbed in baseline exists for all ethnic groups the human body. NIR uniquely penetrates and, in fact, it could be argued that over an inch into our certain ethnic groups are being body (even our skull) disadvantaged by our JV lighting reducing inflammation, approach. Given that we are latitude enhancing cognitive skills, and stimulating mobile, it would appear that an muscle strength optimum HCL baseline needs to adapt to the skin pigmentation of the individual.

Coincidence or Critical Issue? African Americans have the highest dementia death rate (80/100,000) in In some ways the lighting and ATP production in our mitochondria the world nearly twice that of their medical communities seem to be [7]. There also exists new water white American counterparts [13]. headed in opposite directions. research [8] which indicates NIR/IR This is contrasted with black may be fundamental to energy populations at the equator having The three basic tenets are derived storage at a cellular level. some of the lowest dementia death from three observations. Interestingly, there exists between rates (1/100,000) [14]. 90% of 700 and 1000 nm a biological lighting in the Soviet bloc until window [9] in which absorption is recently was incandescent “Ilyvich” The NIR/VIS ratio at a minimum. This allows NIR to bulbs unlike the US and Europe. All natural light sources have NIR/ penetrate over an inch into our Dementia death rates in Russia are VIS ratios greater than 1: bodies even through our skull. (2/100,000) while Finland dementia The majority of our cells only “see” death rates are (53/100,000) [14]. • The NIR/VIS ratio for the sun NIR wavelengths. NIR is, for Myopia rates are skyrocketing ranges from 1 (midday) to 5 example, strongly absorbed by especially in Asian countries which (sunrise/sunset our blood but very weakly absorbed predominately use JV LED lighting • Moonlight is around 2 and by the other surrounding tissue [15]. Horticulture lighting is adding • Fire ranges from 5 to 10 making the blood vessel visible in NIR to enhance growth rates [16]. the NIR not apparent in the VIS. Non VIS circadian cues are 1000s of medical articles indicate Also sclera transmission and being proposed [17]. Macular that NIR functions to protect and absorption varies depending on degeneration is being treated repair our cells via stimulation of the spectral range (Figure 3). with NIR [18].

Figure 5: While the exact root causes for NIR enhanced LED above are unknown, it is reasonable lighting source that to think that lighting plays some role. mimics both the But why is it so hard to establish a intensity and spectral shifts of the sun HCL baseline?

The Need for a HCL Baseline Studies Unlike plants, it is difficult to accurately assess the impact of light on humans as we move around and live a wide range of lifestyles. Given that natural sunlight delivers up to 60 MJ/day of UV/VIS/NIR/IR onto a typical human body and that an incandescent lamp can locally deliver even higher NIR exposure levels when we sit down to read a book, simple variations in lifestyle can significantly impact light exposure studies. In general, there is a lack of long term research which takes into account the total The two proposals: office have LED or fluorescent light exposure of the participants on lighting, do the windows have a daily, weekly, and monthly basis. • Daily, weekly, monthly UV/VIS/NIR NIR reflecting coatings, what are Added to this lack of controlled exposures levels tracking you wearing (e.g NIR transmitting studies, the medical community is • Adopt NIR enhanced LED lighting clothing), etc. can be used to further motivated to develop treatments that mimics the complete refine the accuracy of the monitoring. which can be done within the time circadian spectrum without the With the introduction of NIR cameras constraints of an office visit, need for complex drivers. in cellphones it is now possible to while the lighting community is directly measure UV/VIS/NIR levels motivated to limit the spectral range and input the data into the app. as much as possible to save energy. Light exposure tracking In general, the purpose of the app Neither of those two motivations are An app can accumulate daily, is to expand the spectral range we helpful in determining what the weekly, and monthly exposure “see”, so we can make appropriate optimum HCL baseline should be. data based on the location, time of lifestyle changes. day, and weather conditions. While an estimate, there exists a Proposed Solution - Measure wealth of information that can be NIR enhanced LED lighting and Simplify Lighting accessed from a mobile device. Figure 5 depicts a NIR enhanced The proposed solution consists This combined with some individual LED lighting source that mimics of two parts. responses regarding; does your both the intensity and spectral shifts

Figure 6: U/I diagrams for an LED, an Incandescent and a combined light source

of the sun (Complete Spectrum The author is keenly aware of the filament sources are 90% efficient Circadian™) simply by adjusting heresy associated with bringing at generating NIR most of the the input voltage. The system can filament sources back into lighting. energy consumed is used by the be scaled to any lumen level and While the use of current limiting LEDs (only 40% to 50% efficient) the ratio of NIR/VIS can be adjusted resistors with LEDs are common at peak drive levels depending on for individual preference or skin place, the idea that a couple of what NIR/VIS ratio is selected. Using pigmentation levels. grain of rice filament sources this approach, 80 to 100 lm/W could be used with an LED to source efficiencies are possible with The system is based three eliminate complex drive electronics NIR/VIS greater than 1. The reduced components; a novel CNT Yarn and provide beneficial NIR/IR raw material costs, health benefits, LED package and 2 wire terminal light is somehow taken as a higher reliability, and cost savings filament sources. The filament step backwards. associated with simpler drive sources are non-linear resistors electronics offset any energy penalty used to eliminate the need for While the IP covers a host of incurred by adding NIR back into complex constant current drivers means of creating NIR enhanced our lives. as shown in Figure 6. LED lighting including NIR phosphors, NIR LEDs/LD/VCSELs, As stated earlier the filament Low temperature filament sources and quantum dot converters, sources are 90% efficient and have are the longest living man-made this filament configuration is the longer life expectancy than the light source known (Century bulb) most efficient, cheapest, greenest, LEDs. At these low drive levels the and are 90% efficient at generating longest life expectancy, broadband, only significant thermal load on the NIR/IR light. From room temperature and the simplest HCL solution. LEDs from the filament sources is to operating temperature a filament The life expectancy of small filament via radiation coupling which source increases its resistance sources exceeds 300,000 hours represent only a fraction of the light tenfold. A patent pending series/ when they are not required to emitted by the filament and can be parallel design is used to create the generate significant blue/green light. easily minimized via placement or spectral and intensity IV response They do however provide significant shrouding. Unlike incandescent which mimics the sun simply by orange and red even at these low and halogen sources of the past, adjusting the voltage from zero to drive levels to the benefit of color the function of the filament sources peak voltage (0-15 V in the example quality while they generate copious in these design are only required from figure 5). This eliminates the amounts of NIR. By combining two to match the VIS optical watts need for constant current drivers competitive technologies both outputted by the LEDs. At 90% and flicker associated with PWM technologies benefit. efficiency a small T1 filament bulb dimming methods. The technique run at 80% drive level can output can be used for both DC and AC The majority of the resistance more NIR optical watts than the inputs and scaled to any lumen change in filament sources occurs VIS optical watts generated by a output level. However based on the at lower drive levels. By matching 300 lumen JV LED bulb. previous flicker discussion it is the filament resistance curves with proposed that this solution should the LED IV curves it is possible to To improve the LED reliability, be used as a catalyst to push DC eliminate the need for constant a novel interconnect method was lighting solutions. current drivers. Given that the developed. Using CNT Yarns a

Figure 7: Structure of the proposed LED+Filament light source

TECHNOLOGIES HYBRID LED FOR HCL 68

dual sided CSP emitter can be possible, contains no red listed data appears to support this formed. Unlike conventional solder materials, and is compatible with position. For the last 150 years based connections, the gold/CNT cradle to cradle. we have been removing spectral contacts are glued together using a content from our lighting. high temperature rigid silicone rated NIR Enhanced LED Lighting offers Recent government action, to 600°C. CNT Yarns are inherently a practical, common sense solution lifestyle changes, skin cancer “sticky” due to the large surface that complements all daylighting concerns, and the blind pursuit of area created by millions of fibers efforts. We have a very limited energy savings will eliminate over making up the yarns. In this design knowledge of how light interacts 70% of the solar spectrum from the CNT Yarn serves as both the with our cells, but the deeper we our lives over the next decade. electrical and thermal conductors. look the more we find that light plays There appears however to be no Two Seoul Semiconductor CSP a significant role in our health. data which supports reducing the die are bonded back to back as Lighting should follow the medical spectral range yet numerous shown in Figure 7. community’s lead and adopt a indications to the contrary. “first do no harm” philosophy. The medical community appears By using CNT Yarn instead of metal As the data from the app becomes to be headed in the opposite wire and solder, failures associated available we may be able to limit direction of the lighting community with electromigration are eliminated the spectrum for some individuals. showing the NIR/IR light benefits and a wide range of mounting Until that time the daylighting the body and can even be used to configurations can be used. studies and medical research would treat ailments using energy Typically filament sources and seem to indicate that we should exposure levels similar to those CNT Yarn LED packages are mandate that all artificial lighting we possible in lighting systems. simply crimped or tied together. are spending significant time under There exist practical, energy Additional cooling surface area have a minimum NIR/VIS ratio of efficient, and lower cost solutions can be attached as needed. greater than 1. that don’t require us to compromise. The lumen output can be scaled At this point, standards and either by using additional groups or government programs represent by using high wattage components. Conclusion the most significant hurdle to HCL. In both cases, peak drive levels on For millions of years our cells have It is proposed that the NIR the filaments are maintained at low received a specific spectral and enhanced LED Lighting is consistent levels such that the product lifetime temporal exposure. It is naïve to with daylighting efforts in the is defined by the LEDs not the think that nature has not developed architectural community and should filaments. This design approach mechanisms that take advantage of be mandated for areas in which uses the minimum raw materials this exposure and recent medical there is long term exposure.

References: [1] http://www.wseas.us/e-library/conferences/2013/Malaysia/MACMESE/MACMESE-20.pdf [2] http://valtsus.blogspot.fi/2017/05/the-therapeutic-effects-of-red-and-near.html [3] https://www.sciencedirect.com/science/article/pii/S1011134415300713 [4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4768515/ [5] https://link.springer.com/article/10.1007/s10103-016-2139-9?no-access=true [6] https://www.readbyqxmd.com/read/27874264/photobiomodulation-in-human-muscle-tissue-an-advantage-in-sports-performance [7] http://photobiology.info/Hamblin.html [8] https://www.bing.com/videos/search?q=pollack+4th+phase+of+water+ted&view=detail&mid=DDB895A8CAC1B45D90C3DDB895A8CAC 1B45D90C3&FORM=VIRE [9] https://www.quora.com/Can-near-infrared-NIR-light-penetrate-the-human-body [10] http://www.montana.edu/jshaw/documents/NIR%20Photography%20-%20Mangold%20et%20al%20-%20EJP2013.pdf [11] https://science.mit.edu/news/unique-visual-stimulation-may-be-new-treatment-alzheimer%E2%80%99s [12] http://krex.k-state.edu/dspace/handle/2097/6915 [13] https://www.alz.org/national/documents/report_africanamericanssilentepidemic.pdf [14] http://www.worldlifeexpectancy.com/cause-of-death/alzheimers-dementia/by-country/ [15] https://www.npr.org/sections/goatsandsoda/2015/02/05/383765377/why-is-nearsightedness-skyrocketing-among-chinese-youth [16] https://www.scribd.com/doc/178722716/nir-and-plants-2013 [17] https://www.photonicsonline.com/doc/ultrafast-pulses-modulate-circadian-rhythm-and-blues-0001 [18] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4768515/

ENGINEERING ELECTRICAL OVER STRESS 70 Electrical Over Stress - How to Prevent an LED Failing Earlier than Expected

While LEDS are, in general, very robust, failures still happen due to electrical over stress. Mauro Ceresa, EMEA Field Application Engineer Manager at Cree, will cover all aspects related to electrical over stress, or when an LED fails due to being subjected to a voltage beyond its specification limits. He will explain why the failure occurs and how to prevent this from happening. The article will explain the fundamental aspects of a good PCB layout design and how this is linked to the longevity of an LED.

Solid state light technology has materials. Unfortunately, and expensive to solve. become an important player not all threats to LEDs are The time lapse between the in the lighting industry thanks evident enough so as to enable EOS occurring and the failure to the many performance users to take the necessary to detect the fault can be advantages that LEDs offer. steps to fix the issue before a quite long and have serious The performance enhancements massive field failure occurs. repercussions as more of this rising star technology - luminaires may be produced and its efficiency advantages in The most critical threat comes installed, thereby increasing the particular – have led to many from the same source that cost of warranty replacement. new applications and the powers the LEDs, and is known widespread adoption of LED. as “Electrical Over Stress” (EOS). An EOS occurs every Solid state light usage time the LED driving current or proliferation exposes LEDs to a voltage exceeds the component range of new and harsh working maximum rated values. conditions, and demonstrates There are many different types that their theoretical “great of EOS - some are generated longevity” could easily be during the LED assembling compromised by various or testing process, while others environmental factors. Chemical are produced by the power incompatibility is one of the supply or come from the first issues customers face, environment induced by the but luckily, in most cases, this electromagnetic field. problem tends to become apparent quite rapidly when An EOS is the most dangerous caused by a fixture design fault. threat for solid state light technology because it uses the The speed at which these same path used to light up the faults become evident means LED. In addition, the damage it that the industry is becoming causes is often not immediate. increasingly conscious that the In many cases, the LED may expected lifetime of LEDs could only cease to work days or be seriously compromised if even months after installation. they are exposed to volatile These two characteristics of substances incompatible with an EOS mean it can be solid state light constructing incredibly difficult to prevent,

Figure 1: Why an Electrical Over an electrical over stress should be Low and mid energy Stress Happens considered a device at risk of failure. stress generate a There are many different reasons long term short circuit and ways in which an EOS could failure due to micro damages happen, but there is only one result: Different Types of Electrical LED failure. EOS damages the LED Over Stress and How to chip structure which causes it to fail Prevent Failures faster than its expected lifetime. There are many possible sources of EOS that could be generated by An EOS is caused by external fixture design issues, human error sources like the working and even by the limitations of environment, a test procedure or regulations in place before the Figure 2: human interaction, as well as an solid-state light technology broke High energy creates internal interaction like bad or wrong into the lighting industry. an immediate failure in power supply, PCB design layout, open circuit or faulty components that generate The following will cover all the a voltage or current across the LEDs potential circumstances that can exceeding the maximum voltage cause an EOS, and provide rated in the datasheet. guidance and recommendations to prevent field problems. In some When the voltage or current cases, the solutions are strongly exceeds the component maximum influenced by customer design, rated values, this is called “stress”. which is why it is essential for LED To better understand why an EOS manufacturers to work closely with Figure 3: happens – in both an open or short customers to ensure their fixture LED with invisible micro circuit - and the time it will take for designs are EOS-proof. damages the LED to fail, it’s important to consider the energy content of the stress. Every time a stress is applied Electrostatic discharge to a solid-state light product, The first possible source of EOS is it creates a voltage and a current generated by operators handling which flow through the entire circuit the LED or printed circuit boards. impedance (fixture plus environment). This type of EOS is generated by This means a certain power stress the Electro Static Discharge (ESD). is applied to the LEDs. An ESD is a low-energy event with a electronic devices, and can be very short duration – it only lasts a used to solve this possible EOS If the power stress signal is few microseconds. An ESD is issue if needed. integrated, over time the energy typically generated in non ESD stress will be measured in Joule. protected working environments. Low energy stress generates For instance, the operator body Power supply insignificant damage - or sometimes could have a very different electrical Another possible source of electrical none at all - while mid-energy stress potential from the LED board, over stress comes from the power damages the LED, but failure will and when they come into contact supply used in the luminaire. There are only occur a long time afterwards. with LEDs, an ESD can occur. several possible conditions that could On the other hand, high energy damage the LEDs even in the absence stress immediately causes the LED Typically however, ESDs are not of any misoperation by the user. to break either by blowing up the a problem for LEDs because the Every time a new constant current wire bonds, or melting the die majority of LEDs are equipped with power supply is selected, it is attached to the solder pads. an ESD suppressor which protects mandatory to check output tolerances, the LED chip. Nevertheless, current ripple, transient spikes It’s important to note that even some very small new LEDs which during the switch on and off phase without a failure after a stress, are designed to maximize light and finally, the hot plug current. this does not mean the LED is not density, are not equipped with ESD Tolerances, ripple and spikes could damaged. Low and mid energy suppressors, which is why an be silent LED killers that are stresses could lead to micro external ESD suppressor must be compromising the component damages (Figure 1) that are not used. These additional components integrity without any obvious sign. instantly visible (Figure 3), but these have to be positioned very closely Figure 4 shows a commercial can end in catastrophic failure after to the LED to protect it properly. constant current 1050 mA power a number of working hours. That is These ESD suppressors have been supply, representing many possible why every LED that is exposed to used for decades to protect other sources of EOS.

Figure 4: Ripple of a commercial As discussed previously, if using a a connector, a polarized connector constant current 2 A or higher rated current LED is the best solution. 1050 mA power supply, type, nothing will happen. However, representing many with a 1.2 A maximum current One last test - which is always good possible sources of EOS device, the LED lifetime will be to run - it is a “destructive test” on seriously compromised by the few LED boards to measure the hot constant current power supply. plug current. This test consists of It is also essential to consider the switching on the power supply tolerance of the average current (without connecting any LEDs) and output, which can worsen the then hot plug to the LED board. situation, by increasing all these By doing this, the hot plug current First and foremost, every time a values by the tolerance percentage. peak can be measured (Figure 5) solid-state light fixture is switched that represents the possible on, this power supply generates To prevent EOS failure in the electrical over stress in case of a spike of 2 A per few milliseconds. scenarios described above, it’s bad or wrong electrical contact If the LED type used here is rated important to use power supplies during the luminaire assembly or 2 A or more, there shouldn’t be a with a limited transient peak during test. The peak as seen on Figure 5 problem. However, if the devices the switch on and off phase. is proportional to the difference used have a maximum rated current These power supplies must not between the power supply of 1.2 A, on a constant current exceed the maximum rated current maximum voltage output without 1.05A power supply, one could be of the LED. Moreover, the typical load, and the total forward voltage running a big risk. current combined with the ripple of the LED string. This means and the positive tolerance must not that the higher the gap, the higher If the fixture will be switched on exceed the maximum LED rated the probability of LED damage and off once or twice a day, current. If all these conditions are induced by a misoperation or bad the LED will most probably last as respected, the power supply will electrical contact. long as expected. However, in cases not lead to any EOS. where a presence or movement To prevent EOS failures induced by sensor turns our fixture on and off, Another possible source of failure the hot plug current, it is important the many spikes per hour will stress is the reverse polarity connection of to follow assembly procedures that our LED, thereby compromising the power supply, or negative exclude potential hot plug scenarios its lifetime. pulses. If an operator swaps the and choose appropriate power polarity during the test or production supply and connectors. Another critical aspect of this power phase, the LED will be seriously supply is the ripple. Here, there is damaged by this EOS. To prevent During the assembly process, approximately ±40% of ripple. this from happening, it is good the power supply must not be Beyond a few potential unpleasant practice to use power supply with plugged into the electricity before effects, like flickering and flux short circuit protection and equip the LED board is firmly connected. reduction, this ripple could force the LED board with a diode in Moreover, the LED board must not the LED to work out of specification parallel to the LED string in reverse be disconnected from the power and under stress for continuous, polarity. If the power supply is supply before the power supply has repetitive cycles. connected to the LED board with been turned off. Using a power supply with a built-in current limiter Figure 5: The “hot plug current would also make the assembly peak” test represents operation safer, while also preventing the possible overstress any potential human error. and the probability of LED damage induced by a misoperation can Finally, connector quality is crucial. be estimated Poor quality connectors with a loose electrical contact, act as a hot plug - even if the board is electrically connected to the power supply. Generally, if the LED produces flashes or blink light, a current pulse is likely to be behind it, which could be a sign of an EOS and will require further looking into. By following these simple rules, any possible EOS during the assembly operations can be avoided.

ENGINEERING ELECTRICAL OVER STRESS 74

Figure 6: Badly designed LED to stress due to the change of Transient Voltage setting. The second risk lies in that Suppressor that never the power supply is constantly protects the LED as it running, and the output stage is does not cross the LED curves energized and if the current limiter circuit is positioned before the output capacitors, the current limiter will begin working once the LEDs are already damaged. Despite this being perceived as a very safe LED test mode, it is not.

Field hot-plug and long cables But solid-state light fixtures are not designed to just be kept in warehouses, and many EOS risks exist beyond the production phase. This is why technicians aim to Tests human error is very high. In some anticipate potential EOS triggers Other potential production operation cases, constant current power once a fixture is installed. issues that can generate electrical supply is used, while in others, For outdoor applications, this means over stress include in-circuit and laboratory power supply with considering different weather laboratory tests. These tests present current limiters is the preferred conditions and electromagnetic a high potential for EOS – and hot customer choice - both of which fields, as well as on/off cycles and plug EOS in particular. are very dangerous. In the case of other induced magnetic fields for constant current power supply, indoor applications. In-circuit tests tend to be automated if the sequence is not done every processes and can be useful when time perfectly the LED will be Today, the majority of LED fixtures done properly. In order to avoid the damaged, whereas in the second are equipped with an on-board risk of EOS, it is essential that the case, there are a number of variants driver which protects against machine software carrying out the that could damage the LEDs. hot-plugging during the installation test is programmed to follow this phase. In the early LED adoption step-by-step process: First and When using constant current power era, the three LED MR16 lamps foremost, connect the probes; supply, it is recommended to put were destroyed during the apply the energy to the test circuit; two push buttons on the cord that installation phase by hot-plugging. remove the energy from the circuit connect the power supply to the Having the driver on board or and finally, remove the probes plug. By doing this any operator - together in the fixture housing also contact. By following this process, even an untrained operator – will be prevents EOS caused by the long the driving circuit will successfully forced to connect first the LED cables that connect the LED boards test the LED without causing board to the power supply and then to the power supply, and act like any damage. push down the two buttons. antennae. They connect all the electromagnetic fields produced by In order to ensure that a software Even if the power supply is plugged radio systems, lift motors, etc. bug does not damage the LED, the in, the primary stage is not best option is to use a constant electrified by the two push buttons In some cases, customers position voltage source with a resistor in that are opening the circuit. It would a Transient Voltage Suppressor series to limit the test current. be possible to run this test with just (TVS) on the LED board to prevent This type of test cannot be one button, but installing a second this type of EOS and hot plugs, conducted when measuring the LED saves the operator from pushing but this is not effective for two flux, CCT and Vf, as the forward the button while simultaneously reasons. Firstly, these EOS are high voltage variation from LED to LED connecting the board with the other, frequency signals that bypass could influence these parameters. and just ensures a safer process. these suppressors, and secondly, In all the other cases however, it is a the electrical characteristics of the very safe way to in-circuit test LEDs. When using laboratory power supply LED and the TVS do not match. with a current limiter, there are two Laboratory tests are more critical, main risks – the first being simply Figure 6 shows a series of 12 LED as boards are usually tested that someone might involuntary “typical” and “maximum” forward manually and the potential for move one of the knobs, causing the voltage. The TVS should be selected

ENGINEERING ELECTRICAL OVER STRESS 76

Figure 7: If any of the creepage situations causing EOS, it’s distances or the PCB important to understand industry breakdown voltage is regulation and protection classes. not sufficient, the risk for damage by an EOS is very high The International Electrotechnical Commission (IEC) and the IEC61140:2016 define the rules of protection for people against electric shock. Depending of the country and the type of product, there are different insulation level requirements for the devices sold in each market.

The most commonly-used insulation classifications are Class I and Class II. Class I fixtures must have their with a minimum breakdown voltage screw head diameter and not the housing connected to the electrical greater than the maximum LED PCB hole. When wires are fused earth with a dedicated cable. forward voltage at the maximum on the PCB instead of using the Class II fixtures on the other hand, driving condition. This is essential connector, it’s very important that are designed to provide the required because the TVS parallel to the LED the cable wire insulation covers the level of safety without any electrical string must not absorb any power in soldering pad and does not reduce earth connection. standard working conditions. the creepage distance. In Figure 6, the green TVS curve Protection Classes Symbols never crosses the LED curves, PCB used for LED boards is which means that the TVS will never typically aluminum-based. Class I Class II protect the LED. Instead, the LED The aluminum and copper are absorbs the entire EOD. separated by a dielectric material that provides the electrical insulation We will explore in detail how to between both metals. This dielectric design a circuit to protect against should be thin enough to guarantee common mode or differential mode a good thermal transfer from the EOS, but first the best PCB design LED to the fixture housing, but thick will be discussed. enough to provide sufficient These two different classifications electrical insulation. Normally the make the solid-state light fixture PCB aluminum is in direct contact behave in a completely different way PCB design with the fixture heat sink, so the when exposed to environmental To avoid any potential dangerous unique insulation is guaranteed by stresses. In general, if the electrical conductive path between the fixture the PCB dielectric. For this reason, earth connection is done in an housing or heat sink and the LED it is crucial that the PCB vendor effective and reliable way, the Class pads, it is very important that the guarantee the minimum value of the I luminaries suffer less from EOS Printed Circuit Board (PCB) be PCB breakdown voltage for all the failure but in reality, both luminaire designed to keep an appropriate PCB supplied. types need to be designed creepage distance from the copper efficiently to prevent EOS damage. pads and the edges of other metal If any of the creepage distances parts connected to the housing. or the PCB breakdown voltage is Another crucial regulation to not sufficient to withstand the consider is the IEC60598-1:2014 In Figure 7, any copper path close to environment surges, there is a that defines the general the edge must be kept over the risk that electrical arches and requirements and tests for insulation distance. The minimum discharges will occur and the LED luminaries, including the solid-state suggested distance is 3 mm, even will be stressed and damaged by light fixtures. This 2014 edition though the recommended distance an EOS (Figure 7). replaced the 2008 version, is generally anything from 5-7 mm and provides a relevant change for when feasible. Class II products. Common and differential Another critical consideration of mode surge Paragraph 10; Section 4 of PCB design are the copper traces Most LED users will probably be IEC60598-1:2014 on “Construction”, close to the screws. The distance familiar with the scenarios outlined addresses the double insulation must be calculated considering the above. Before exploring further Class II luminaires. Sub-paragraph

Figure 8: 4 (IV.10.4) of the chapter specifies A simple model of two the protective impedance device, LEDs in series with an stating that accessible conductive ESD protector parts separated by double insulation may act as a conductive bridge using resistors or Y2 capacitors. They need to consist of at least two separate components of the same rated value. Figure 9: Simplified model of an These components must comply LED and TVS with a with appropriate IEC regulation. capacitor With Class II luminaires, it is possible to add specific components connecting LED boards to the fixture body. This makes it possible to analyze what the LED circuit looks like during fast transient stress. Figure 8 shows two LEDs in series with a simple model that shows the LED and the ESD protector built-in in their package.

This model does not consider all the parasitic components or the influence of the LED thermal pad. The thermal pad is a vital pad that Figure 10: allows the LED to efficiently transfer Leaving LED and TVS the heat from the source (junction) floating is a relatively to the air via many metal parts. unsafe option

For a very good thermal transfer, the thermal pad should be connected to a very large copper area on PCB. This spreads the heat horizontally and then efficiently transfers it vertically to the aluminum layer of the PCB, thanks to the large transfer area. Two metals separated by an insulator create a capacitor, which means that PCBs are capacitors that should be considered in this particular analysis. Because of the parasitic by the blue arrows (Figure 10), This parasitic capacitance could capacitance between each thermal exceed the LED package insulation. be big or small depending on the pad to the ground, it’s important to PCB design and the material used. understand how to connect them. With regards to the LED package It cannot be ignored and it is There are two options: Leave them material, ceramic provides much important to understand how separate or connect them. better insulation than plastic, to manage it in order to avoid and depending on the distances EOS problems. There is also is the option to leave between pads, it’s possible to have them electrically floating or to a package insulation voltage ranging LED and TVS could be modeled in connect them to an electrical from a few tens to hundreds of volts. very complex way, and for people voltage potential. Leaving them In any case, common mode signals who enjoy spending hours in floating is a relatively unsafe option, could reach easily thousands of simulations, this is a great way to as any common mode stress is volts, thereby generating an have fun. For the purpose of this applied directly between the thermal electrical over stress to the LEDs. paper, just a simplified model with pad and the LED electrical pads - the capacitor connected electronically anode and cathode. This creates a Connecting the LED thermal pad to in parallel to the other components fatal EOS as soon as the voltage a voltage reference protects the LED is used, as illustrated in Figure 9. drop between the points marked from EOS generated by common

Figure 11: Luminaire stress When the thermal pads are connected caused by a differential to the cathode, the positive stress mode (red arrow shows totally passes through the first LED, the direction of the damaging it more than in the stress signal on a positive surge, while previous case with the anode the blue arrow is on a connection. However, in the event of negative surge) negative stress, the last LED of the series is less stressed.

Thanks to this first analysis, the LED thermal pad should be connected all together and then connected on anode for positive stress, and on cathode for negative stress. It is not possible to know which type of Figure 12: Dividing the LED string stress (positive or negative) a in two groups with a luminaire is facing; therefore the best mirror configuration is configuration is a symmetrical one the best configuration which divides the LED string in two as one does not know which type of stress groups with a mirror configuration (positive or negative) (Figure 12). The thermal pad of the will occur LED on the positive side must be connected to the anode, and the one on the negative side, must be connected to the cathode.

To improve the protection of this strong solution even further, two additional capacitors CP and CN on mode voltage stress. The signal the thermal pad. It is evident that by positive and negative LED groups follows the path towards the earth, connecting the thermal pad, the are added. The thermal pad areas via the thermal pad parasitic parasitic capacitance is n times and CP and CN must be designed capacitance, and the voltage across bigger (where n is the number of and selected properly, but this is the LED package is limited. Now the LEDs), and the impedance is n possible only when working on a need to connect the thermal pad to times smaller – absorbing a big part physical customer circuit. One must some electrical potential is clear, of the stress. not forget that IEC 60598-1:2014 but there is still the option to keep allows to use proper components to them separate or connect them all. This means that it is better to connect the luminaire body to the connect all thermal pads than positive or negative terminals of the Figure 11 shows the circuit of the leaving them separate. In case of a power supply output. This will luminaire stressed by a differential negative stress signal, the entire further reduce the potential EOS mode. The red arrow shows the signal will pass through the CLED, impacts on the LEDs. direction of the stress signal on a polarizing the LED in the reverse positive surge, while the blue arrow way. The impedance of CLED is is on a negative surge. For the quite high – and therefore the Conclusions purpose of this discussion, reverse voltage drop will be quite A number of conditions can generate the thermal pad’s connection to the high too. The ESD TVS contributes EOS, which is why they are still the anode as well as its connection to to clamping the signal, but because main cause of LED failure before the the cathode will be covered. the stress is more in the mid-range end of an LED expected lifetime. energy, the LED is EOS damaged by The reasons for EOS are complex, In the case of a positive surge and this reverse polarization. and the operations and variable the thermal pad is connected to conditions that can lead to an EOS the anode, the stress will be split When the signal occurs after the are multiple. between the standard path through first LED, it finds the thermal pad the LED string and the parasitic parasitic capacitance to reach the The above explores all the possible capacitance between the thermal electrical earth. Other LEDs on the harmful conditions and summarizes pad and the earth. The split ratio is string become stressed, but less the measures to be taken during the determined by the impedance ratio and less so, as each C thermal pad luminaire production process and at of the LED path towards the earth on the series absorbs part of the circuit level, to make each solid-state and the first parasitic capacitance of stress signal. luminaire safer and long-lasting.

ENGINEERING CONSTANT LIGHT OUTPUT OPERATION 80 Method and Circuit to Maintain Constant Light Output for LED Luminaires

It is difficult to accurately predict the lifetime or the light output degradation of LED luminaires. A Constant Light Output (CLO) operation is implemented in some of the latest drivers. However, there are many factors that require a different algorithm in terms of time rate and forward current values that are usually not taken into account. Prof.Dr.Eng. Stelian Matei, from the Photometry and Electromagnetic Compatibility Laboratory at Electromagnetica SA, proposes and explains a new method is maintaining the luminous fux over the lifetime of the LED luminaire, considering the luminaire global light degradation.

Accurate lifetime prediction or Basically IEC 62722 tolerate Balanced Light Output (BLO) estimation of the light output replacing LED luminaire lumen To include all combined effects in a degradation for LED luminaires maintenance with LED emitting CLO operation should require a is difficult. The reason is the surface as long such data is different procedure otherwise may diversity of LED technologies available. Most of the LED not be any longer of a preset and the particular contribution lighting system manufacturers stepping type. Such a dynamic of the system components such are declaring luminaire lifetime Balanced Light Output (BLO) as lens, driver, heatsink, etc., based on this acceptance method is maintaining the luminous to this process. The life of an despite the complexity of this flux over the lifetime of the LED LED luminaire is the combined matter. The latest generation luminaire, considering the real effect of gradual light output of LED drivers is managing luminaire global light degradation degradation caused by material this problem by employing instead of LED projected life. degradation and abrupt light a Constant Light Output The process starts by establishing a output degradation mostly (CLO) operation. This CLO reference, respectively an equivalent caused by LED components feature increases the forward value number allocated to the initial failure. There are a set of current at specific time rate, luminous flux, may also be called a standards defining how LED disregarding overall luminaire preset flux, together with an luminaires can be tested to performance. Ultimately based equivalent value number of the light determine their performance on a prediction supposedly transmission through the diffuser or over time such as: applying to any LED technology the optical system (transparency or and luminaire configuration. transmittance) as measured by a Standards for LED Unfortunately regardless of sensor. Therefore the reference is lifetime testing: the CLO type procedure the a numerical value that is in a • LM-84-14 and TM-28-14 method does not compensate mathematical relation to the • IEC 62772 luminaire real light output degradation metrological value of these performance of the luminaire even for same characteristics. Ultimately these type of LEDs, otherwise even reference values of transmittance According to IEC 62722-2-1, the the constant light output may and luminous flux are used through LED luminaires using modules not be achieved. In reality there a mathematical process to in conformity to IEC 62717 are many factors that require a determine the overall level of light definition, may be declared the different algorithm in terms of degradation of the apparatus. lumen maintenance value for time rate and forward current The photometric performance, the module as the maintenance values as to maintain a genuine respectively, the maintenance of the value of the luminaire. constant light output. luminous flux over the operating

Figure 1: Flux depreciation due to the thermal balance

Figure 2: Normalized lumen output over time

time, is analyzed in relation to the decreasing toward balance and contribution, instead of a single LED reference values in real time. Finally, may be observed if the input power test data as a proxy. the results control the LED’s supply variation of the LED luminaire is current, through the dimming feature recorded. Practically, a well- of the power supply in order to designed luminaire, has a very low Estimating Light degradation balance the difference in respect to variation (perhaps 2-3% is Hence, the CLO method uses the the overall initial light output acceptable), as a right balance data based LM80 report provided performance. between total LED power and the by LED manufacturers, then, long heatsink size/shape. term luminous flux maintenance for LEDs is basically estimated by a Light degradation process Long term light output degradation mathematical process as explained Decreasing the light output of a beyond thermal balance is caused in TM 21, instead of the real one. luminaire during operation is mainly by LED’s, the optical material and According to the TM-21-11, values caused by depreciation of the light electronics aging. Measurements of during a minimum of 6,000 source, the diminution of light the luminaire’s long term light operating hours are processed by transmission through the degradation are carried under strict approximation exponential transparent screen (otherwise controlled conditions (basically in a regression and then statistically diffuser), the reduction of the power laboratory) in respect to procedures estimating the light degradation six of the power supply and the ambient as specified in standards. For lamps times beyond this period temperature conditions. Short term and luminaires data collection light depreciation is mainly caused procedure is specified in LM 84-14 Approximation by exponential by LED’s reaching the thermal and projection for the luminous flux regression is expressed by EQ1: balance (Figure 1). Since the forward method stated in TM 28-14. Both -α∙t voltage varies with temperature, the these normatives consider the Φt = B ∙ e (EQ1) output power delivered to LEDs is luminaire‘s components

Figure 3: Lumen output over time with curve-fit through the average values

Figure 4: TM-21 time projection derived from 6000 hours testing

Table 1: Example of test results Where: To project the luminous flux Test Condition – 85°C Case Temp t operating time (in hours) maintenance beyond test period Φ(t) averaged normalized luminous (6000 hours), TM-21 state the Sample size 10 flux at time t following equation: Number of 0 B projected initial constant by the failures least squares curve-fit of B ln ___ DUT drive LM-80 data 0.7 current used in 150 ______the test (mA) α decay rate constant derived by L70 = (EQ2) α the least squares curve-fit of Test duration 6000 LM-80 data (hours) Table 1 shows an example of Test duration When the test period is concluded, such a result. Otherwise, used for 1,200 - 6,000 the data are normalized for each the results estimate an 80.23% projection (hour to hour) device to a value of 1 (100%) at depreciation level for luminous 0 hours and then averaged within flux after 36,000 hours operating Tested case the same data set (Figure 2). time (Figure 4). temperature 85 (⁰C)

In order to acquire the decay rate for It is unlikely that the real behavior α 6.49255E-06 the test period, an exponential last during operating hours of the B 1.013505744 square curve-fit through the average luminaire, in real conditions is Reported values is performed (Figure 3), known to be predicted beyond a >33000 L70(6k) (hours) in accordance with EQ1. certain range. Obviously light

ENGINEERING CONSTANT LIGHT OUTPUT OPERATION 84

Figure 5: Example of CLO control type

Figure 6: Example of stepping CLO control type

output depreciation of the Constant Light Output (CLO) useful life. One of the algorithms luminaires is mainly caused by As explained previously, lumen may be expressed by EQ3. the thermal stress of the LED maintenance beyond the test period emitters, but may also be caused is based on a statistical calculation, One algorithm for compensating by aging or messing up the otherwise called projection method. light output degradation: transparent screen or the optical There are not too many methods ___ t - τ system. These two combined to compensate the light output It = IN (1 - e ) (EQ3) depreciation processes are degradation caused by a combination difficult to predict, otherwise the of elements. The CLO method Where:

result is reducing the level of simply periodically increases the It forward current at time t

illumination and affect function current through LEDs in order to IN nominal forward current of which was employed (Ex.: the compensate a presumed luminaire’s t operation time safety and security of users in light output degradation. This system τ time constant applications such as street lighting). compensates a predicted depreciation The implementation of a solution of luminous flux through a fixed Without remote management this to offset these processes algorithm irrespective to LED means simply increasing the initial is therefore justified; especially technology or environmental power upon installation in order to for street lighting. conditions to ensure a predefined make up for luminous depreciation. lighting level during the luminaire's By precisely controlling luminous

Figure 7: flux, by means of forward current BLO system assembly through LEDs can control the energy necessary to reach the required level (Figure 5).

Another way is to compensate at a fixed rate, for example 1% for every 7500 operation hours (Figure 6). Obviously both methods do not consider LED type/technology, optics degradation power supply as a complete system and Figure 8: environmental conditions. Sensor assembly side view Regardless of the procedure type, the CLO method does not compensate real light output degradation of the luminaire even for the same type of LEDs. Considering that other system elements behave similarly as power supply, lenses, etc., the luminous flux for the LED type degrades differently, mainly as a result of

Tj difference.

Figure 9: Dynamic Balanced Reflective wall (left) Light Output (BLO) and the sensor Balanced Light Output method is assembly (right) maintaining the luminous flux, therefore the level of illumination, over the lifetime of the LED luminaire, considering the luminaire’s global light degradation instead of LEDs projected. Obviously, an increase in luminous flux is the result of forward current increase through LEDs and a sensor assembly that ultimately respectively the height of the LED consequently, precaution needs controls the power supply driver emitters, space availability and the to be taken in regards to thermal via a microprocessor. The sensor type and size of the optics. management. In this regard the assembly consists of an IR-infrared heatsink should be designed to emitter-receiver pair, which together The VIS sensor, which is indirectly accept the maximum LED output detects the transmission through facing the LED emitters will perform power when it reaches maximum the screen/diffuser. Measurement of the function of measuring the balance light output in order to the light output generated by the equivalent value of the total avoid the LED’s junction from LED emitters inside of the luminaire luminous flux. The sensor’s position overheating. For example a 100 W is performed by a visible VIS sensor. should allow only the detection of LED luminaire should have a light generated by the LED emitters, thermal capability of a 120 W The sensors assembly is mounted which is accomplished by using a luminaire equivalent to a L80 lumen on the surface of the radiator at reflective wall as in figure 9. maintenance at the end of life. some distance from the screen / diffuser (Figure 8). Between the Thus, a ratio between the total Such a BLO system could be transmitter and the receiver is a lumen output of the luminaire and employed inside of a LED luminaire, technological distance and the the electrical signal generated by consisting in principle of a body / VIS sensor is indirectly facing the the VIS sensor can be established assembly as the luminaire’s heatsink LEDs (Figure 9). for system calibration. The value of having a transparent screen or light this signal is equivalent to the diffuser and a LED light source Suitable arrangement for sensor luminous flux value or the reference (Figure 7). The light generated by assembly depend on the mechanical value for assessing the level of the LED emitters is monitored by characteristics of the luminaire, light degradation.

Figure 10: Sensors assembly top Transmission of light through the view transparent screen (transmittance) is determined by the IR sensors pair. The IR beam generated by the emitter is projected onto the diffuser at the angle α (Figure 12). The intersection with the viewing angle β of the IR sensor on the surface of the screen takes place over the distance D. The intersection surface of the projections of the two cones, respectively, of the sensor, on the surface of the screen is Figure 11: Actual sensors represented by the intersection of assembly two circles corresponding to α and β (Figure 13). When the distance between the transmitter and receiver tends to 0, then L ~ h therefore the projection of the generated beam is practically covered by the viewing angle.

Figure 14 shows the trajectory of the IR beam through the transparent diffuser material. The light transmitted by the IR transmitter is reflected in the A direction by the inner surface of the diffuser, but travels in the C direction towards the exterior, throughout the material to the air.

Figure 12: Transmittance When the diffuser’s material measurement deteriorates, the component in C direction increases (Figure 14) and is redirected inside the diffuser’s material, heading the IR receiver. The damage process is caused by the aging of the transparent material, dirt, deformation, or breakage. The degree of damage may be calibrated by a reflection reference material as applied on the surface of the screen. Such a reference material, also known as the "gray card", should allow for Figure 13: Projected areas on developing a relationship between diffuser for larger L the degree of damage and the distance between signal produced by the sensor. sensors When the diffuser is new, in the very beginning, the level of the signal is recorded and used in the calculation process as a reference value.

The photometric performance, respectively, the maintenance of the luminous flux over the operating time, is analyzed in relation to the recorded reference values.

ENGINEERING CONSTANT LIGHT OUTPUT OPERATION 88

Figure 14: Projected areas on the Maintaining the luminous flux is diffuser for smaller achieved by increasing or L distance between decreasing the forward current sensors through LED emitters, referring to

the reference values of ΦRef and TRef. For a LED current driver this action is equivalent to a dimming function, time related to the light degradation.

Figure 15 illustrates the flow diagram of the BLO computing process. Figure 15: Flow diagram of the When the luminaire is switched ON, BLO process a pulse activates a timer in order to generate pulses every 60 min. Each pulse increment increases the hour counter by 1 in order to record the operating hours. When the hour counter has a value of 1 (n = 1), otherwise the very first operating

hour, the initial flux ΦRef and

transmittance values TRef are recorded from VIS, respectively, IR sensors. Recording these values

(ΦEch, TEch) after the first hour, it can be considered that the luminaire reached the thermal equilibrium and thus the stabilization of the parameters (variables) have been achieved. Moreover, the counter (4) triggers every hour reading variables

routine (7), in this order: ΦEch flux reading in (8), followed by reading transmittance TEch in (11). Signal value from the VIS sensor is recorded after each hour in (9). The very first value or the reference

ΦRef is stored in (10), only if the block output (6) indicates as a first operating time. Equivalent flux reading is accomplished in (8), every hour. Once the data is released in (9) triggered the block (11) for transmittance measurement whose value is recorded in (13). The mathematical processing, equivalent to the degradation calculation in relation to the reference values (EQ4 and EQ5) The variation of the luminous flux The variation of the transmittance are completed in (12). from the initial or reference value is from the initial value is expressed expressed by the equation: by the equation: Therefore the results from the flow diagram are: ΔΦ = Φ - Φ (EQ4) ΔT = T - T (EQ5) v Ref Ech v Ref Ech ΔΦ ______V LF = (EQ6) Where: Where: ΦRef

ΔΦ represents the luminous flux ΔT represents the transmittance v v ΔT variation variation between ______V LT = (EQ7) T ΦEch the measured flux value TEch the measured value Ref

ΦRef the reference flux value TRef reference value

| LF | ≥ 0.2

| LT | ≥ 0.2

When | LF | and | LT | are greater than 0.2, then an alarm signal is generated as the maximum dimming threshold of 20% is exceeded. Both ratios, relative to the reference values are summed up in (14).

Result of (14):

RDg = LF + LT (EQ8)

This represents the equivalent numerical value for the overall light output degradation, otherwise essential in the Balance Light Output process. Furthermore, conversion to a PWM dimming signal, as required to control the power supply / driver, is completed in (15) and recorded in block (16), so that it can be saved as it changes with the operating time.

It is advisable that power control not exceed 20% over of the nominal value so that the luminous flux increasing action does not affect the thermal management of the luminaire unless a thermal reserve was provided.

Conclusion Unfortunately, regardless of the CLO type procedure, the method does not compensate real light output degradation of the luminaire even for the same type of LEDs. The decrease of the lumen output is predicted with a certain tolerance with information LED luminaire manufacturers gathered from past products launched and marketed.

The Balance Light Output (BLO) option offers guarantied constant light levels through luminaire lifetime. Hence, the driver’s dimming feature, combined with the BLO platform, enables the environment to have a constant light output. The driver controls the power provided to the LEDs ensuring an equal lighting intensity throughout the lumen depreciation period.

Therefore, BLO features take account of: • Global depreciation curve of the luminaire, based on the real time measurement. • Provides luminaire real lumen maintenance not predicted by photometry during lifetime of the product. • Avoids site over lighting situation that would be happening with standard LED lights for half of product’s useful life. • Autonomous, no input needed from the customer. • Customized program.

The BLO option now provides the possibility of adapting an LED power supply to the lumen depreciation curve for the product’s entire life cycle.

Imprint Next LpR LED professional Review (LpR), ISSN 1993-890X SMART MANUFACTURING & TESTING Publishing Company Issue 67 - May/June 2018 Luger Research e.U. TECH-TALKS BREGENZ Institute for Innovation & Technology Moosmahdstrasse 30 Ken Munro - Partner and Founder of Pen Test Partners A 6850 Dornbirn, Austria / Europe phone +43 5572 39 44 89 Ken Munro works for Pen Test Partners, fax +43 5572 20 60 70 a company that specializes in the security of the Internet of Things. He is a so-called info(at)lugerresearch.com ethical hacker. At LpS 2017 he demonstrated www.lugerresearch.com shocking security leaks. In the interview he talked about what else can go wrong and Publisher how engineers can avoid mistakes in Siegfried Luger +43 699 11 33 55 70 product design and applications. To sum s.luger(at)led-professional.com things up he also explained why the end Editor-in-Chief user should be better informed about how Arno Grabher-Meyer +43 699 11 33 55 18 to correctly operate a system in order to be a.g-m(at)led-professional.com as safe as possible. Int. Account Manager RESEARCH Theresa Koenig +43 699 11 33 55 20 theresa.koenig(at)led-professional.com LED professional Review (LpR) - “Best Papers” at LpS 2017: Annual Subscriptions Automatic Panel Level Transient MarCom Manager LpR Digital Magazine Thermal Tester Bronwen Rolls +44 797 401 2962 • 6 issues The thermal resistance junction in case bronwen.rolls(at)led-professional.com • pdf download is an important parameter for the • high resolution pictures and graphs reliability of LEDs because degradation Your Sales Contacts • printable of the LED is temperature driven. Int. Sales Manager • commercial use Transient thermal analysis (TTA) is still work Brigitte Lindner +43 699 11 33 55 19 • access to all previous issues and time consuming and not automated. brigitte.lindner(at)led-professional.com • Euro 78.80 The authors present and discuss an automatic panel level TTA tester. China, Hong-Kong LpR Printed Magazine They explain the challenges and the Iris Yuen +86 1380 27 01 367 • 6 issues solution and demonstrate the applicability irisyuen88(at)gmail.com • Euro 158.40 of using LED test board-panels.. Germany http://www.led-professional.com/ Armin Wezel +49 30 526 891 92 subscription MANUFACTURING armin(at)eurokom-media.de Manufacturing Revolution Entering India the LED Lighting Industry Priyanka Rai +91 124 478 7331 priyanka.rai(at)binarysemantics.com Western business investments in local manufacturing facilities have been declining Japan since the 1980s due to partnering with Eiji Yoshikawa +81 3 6751 0090 contract manufacturers in Asia. But with scala(at)s3.dion.ne.jp increasing and hidden costs in Asia South Korea companies are now seeking to bring Jung Won Suh +82 2 78 58 222 manufacturing back home. A recent sinsegi-2(at)sinsegimedia.info Cover-page innovation, micro-factories could be the solution. The authors present the micro- Taiwan Artwork: Thomas Klobassa, factory as a new, flexible manufacturing Leon Chen +886 2 256 81 786-10 ©LED professional 2017 concept, and analyze the benefits of local, leon(at)jkmedia.com.tw Main Image: Arno Grabher-Meyer, automated production of LED lighting UK, Ireland, Benelux, Scandinavia products, as an alternative to contract LED professional Zena Coupé +44 1923 85 25 37 manufacturing in Asia. zena(at)expomedia.biz US East TECHNOLOGIES Karen C Smith-Kernc +1 717 397 7100 Integrating Lighting in the KarenKCS(at)aol.com Internet of Things US West & Canada Following the rapid penetration of LEDs Alan A. Kernc +1 717 397 7100 lighting now becomes integrated into the AlanKCS(at)aol.com Internet of Things. Over the past three years a consortium of leading European companies worked on the OpenAIS Copyrights - Luger Research e.U. project, partly funded by the EU within the The editors make every reasonable effort to verify the information Horizon 2020 program, now showing the published, but Luger Research e.U. assumes no responsibility for the results working at a full size demonstrator. validity of any manufacturers, non profit organizations or individuals claims The authors show how OpenAIS creates or statements. an open ecosystem to enable a wider Luger Research e.U. does not assume and hereby disclaims any liability to any person for any loss or damage caused by errors or omissions in the community to deliver the smartness of material contained herein, regardless of whether such errors result from light and they explain how it is possible to Presentation of Samsung’s LED CoB negligence, accident or any other cause whatsoever. You may not copy, adapt the system to cater to the diversity reproduce, republish, download, post, broadcast, transmit, make available and module portfolio at their booth at of people and demands. to the public, or otherwise use LED professional Review (LpR) content Light + Building 2016 subject to change without prior written consent from Luger Research e.U. - Institute for Innovation & Technology, Austria.