Lighting trends in the spotlight From MULTIBEAM LED to HUD Technology

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At the eleventh International Symposium on Automotive Lighting (ISAL 2015), presenters offered the world a glimpse of lighting technologies that may soon appear in production cars. At the congress held in Darmstadt Audi guest speakers discussed recent trends and developments in automotive lighting technology as well as unveiling a state-of- the-art Audi E-tron Quattro concept car with the latest Matrix OLED technology.

Commonly accepted as leaders in automotive lighting technology, Audi has set several milestones: From LED daytime running lights on the W12 (2004) and the first all-LED headlights in the (2008) to the networking of headlights with navigation data in the Audi A8 (2010) and dynamic-display turn signal lights on the Audi R8 (2012) and finally the Matrix LED headlights on the Audi A8 (2013) and the high-beam laser spot in the Audi R8 LMX (2014).

The 2015 IAA Audi E-tron Quattro concept car showcases the latest generation Matrix OLED lights. In this latest development, each OLED (Organic light emitting diode) unit has two electrodes, at least one of which is transparent.

By using numerous layers of micro organic-semiconductor materials the emitted light sets new standards for homogeneity, whilst allowing infinitely variable dimming. The system casts no shadows and does not require any reflectors, light guides or similar optical components. The new flexible substrate materials lend themselves to three-dimensional modelling which will also give stylists a new level of design freedom.

According to Stephan Berlitz, Head of Development for Lighting Innovations at Audi, Matrix LED and Matrix Laser technologies have significant benefits in emerging technologies: In one such development Audi plans to integrate camera systems into Car-to-X technologies to accurately control the light with the intention of enhancing the driver’s field of vision.

Dubbed as “construction zone lighting”, Audi engineers are working on using this controlled lighting to project the vehicle’s width onto the roadway as precisely defined strips of light. These markers will guide drivers as they travel through normally unlit narrow bottleneck areas.

In another development Osram Opto Semiconductors have produced the Oslon Black Flat S; a 2000 lumen LED prototype that uses surface mount technology (SMT).

Utilising five high-current UX 3 generation chips a high luminous flux is produced from a single light emitting diode (LED). With a footprint of 3.75 mm x 7.9 mm. a single LED is capable of powering low-beam and high-beam systems.

The prototype LED operates with a current draw of 2 A at a voltage of 15.5 V. with an optical output of 6.5 W. Operating at a temperature of only 69°C at an ambient temperature of 25°C, the excellent thermal connection with the package allows for passive cooling, which significantly reduces system costs.

These attributes make the Oslon Black Flat S a viable alternative to HID (High Intensity Discharge) lamps and is scheduled to be added to the Osram automotive portfolio at the end of 2016.

LED technology offers several significant advantages over current lighting systems: The light from the very bright LED is closer to daylight and therefore perfectly attuned to the human eye. Studies have shown that the closer the colour of artificial light is to daylight, the less the strain on the eyes. With a colour temperature of 5500 kelvin, LED light is closer to daylight (6500 K) than that produced by xenon (4200 K).

Multibeam LED headlamps offer unsurpassed lighting

The powerful, high lumen/watt output single-chip LED diodes of the latest Multibeam LED headlamps significantly improve efficiency over current xenon technology; and with an average useful life of about 10,000 hours will also last five times longer. According to Development Engineer Florian Herold, Mercedes-Benz have been fitting dynamic all-LED high-performance headlamps with adaptive light function to the CLS-Class since 2010.

Taking this a step further Mercedes-Benz is now fitting new Multibeam LED headlamps to the latest generation CLS-Class. In the latest system high-resolution precision LED modules, each with 24 individually controlled high-performance LEDs, automatically illuminate the road with an exceptionally bright light. Because this light is precision-controlled there is also no danger of dazzling other road users.

To achieve this, a camera positioned behind the windscreen supplies information to four control units which adjust the light pattern 100 times per second. This anticipatory camera- based active light function delivers significantly improved lighting on bends and facilitates a new navigation-based light function for roundabouts.

Prof Dr Thomas Weber, Member of the Daimler Board of Management responsible for Group Research explains that the improvement in performance of the latest system is due to the new dazzle-free main beam: Using the camera positioned behind the front windscreen it detects oncoming traffic or vehicles in front, and mechanically masks them out in the light cone of the main beam so that the drivers are not dazzled. Because of this the high-beam headlamps, which increase the range by about 20%, can be used at all times without irritating or endangering other road users.

In addition to the powerful high-resolution, precision main-beam module, each multibeam LED contains a separate module equipped with four LEDs for the low-beam. This module can be swiveled by as much as twelve degrees to provide an anticipatory camera- based active light function as the driver enters a bend, even before the driver has turned the wheel, thus providing optimum illumination of the bend: And depending on the conditions, it will return to the straight-ahead position before the bend ends. This anticipatory control allows an additional range of between 30 and 60 m depending on the conditions.

Although external LED lighting solutions are grabbing the headlines, internal lighting will probably be what many marketing managers and consumers will love.

German lighting specialist, HELLA, has developed an interior light concept for Chevrolet's 2016 Camaro which was unveiled for the first time in Europe at the Frankfurt International Motor Show.

Modern interior lighting sets the mood

In the 2016 Camaro ambient interior lighting plays a major role in the overall driving experience and is controlled from the first navigation level of the infotainment system. From here, the driver can choose from 24 different colors, link the color of the interior lighting to the driving mode or even activate a 'show mode'.

For the first time ever, colours can be transformed dynamically: Starting from the center screen, the color change moves to the drinks holder and doors, creating a novel experience for the driver.

The driver can also link the interior lighting to the driving mode; for example a gentle blue interior when in 'cruise mode' or a strong orange in 'track mode': 'Show mode"' is a light show which can be activated with the vehicle in park, and illuminates the interior in various color families in a predefined sequence.

To achieve this level of dynamic flexibility calibration of the LED modules during the

production process becomes more complex. Not only do the LED colors have to be selected, but they also have to be sorted by intensity and brightness. The correction matrix produced for each individual LED chip also contains information about the material's color change.

Whilst mood setting lighting could be a very visible application of LED technology, Heads- Up Displays (HUDs) are infinitely more complex.

LEDs enable HUD technology

When it comes to automotive HMIs, head-up displays are, despite isolated criticism, regarded as a technology of the future. LED manufacturer Osram recently revealed the Oslon Compact CL, a high-power LED with a colour coordinate matched to the relevant white point requirements of TFT displays.

The quality of a HUD depends largely on the light source: TFT displays typically use white LEDs as the light source as these offer impressive performance, with full-colour display and excellent contrast.

The Oslon Compact CL chip has a number of properties that make it ideal for use in head-up displays:

 Its extremely compact package measures only 1.9 mm x 1.5 mm x 0.75 mm so the LED can be arranged very close to the TFT display (< 100 µm). This results not only in high efficiency and excellent optical characteristics, but also requires a minimal mounting depth.  The colour coordinate in the colour triangle is cx 0.28/cy 0.25, producing a slightly bluish white light. The TFT display filters out the blue component, leaving a pure white light from which the entire color spectrum can be generated. As a ceramic component, the Oslon Compact CL has a small thermal resistance of only 8K/W, and the resultant heat is quickly dispersed so that the color coordinate remains constant even at high temperatures.  The typical luminous flux of a single LED is 260 lm at an operating current of 1 A, and 350 lm at 1.5 A. With these high light outputs the Oslon Compact CL is also fit for the next generation of head-up displays which will provide even more information (augmented reality) in the driver’s field of vision.

With Car to X and 48V electrification looming on the horizon, the world can expect some amazing developments in the near future, but it would be hard to imagine a world of light without some form of LED.

Author: Peter Els

Dear Lighting Expert, The 16th International Conference on Intelligent Automotive Lighting will once again provide you with the latest industry developments.

Early confirmed speakers include:

 Patrick Graas, Innovation & International Development Director, Valeo Lighting Systems  Dr.-Ing. Christian May, Head of Division Flexible Organic Electronics, Fraunhofer Institute

 Paul-Henri Matha, Lighting Expert, Renault S.A.S.

 Shammika Wickramasinghe, Technical Specialist

Exterior Lighting, Jaguar Land Rover

You will meet experts from along the value chain for maximum knowledge transfer, professional exchange and networking opportunities. For more information and the schedule of events, please download the agenda. If you have any questions, please email at [email protected] or call +49 (0) 30 20 913 - 274 We look forward to meeting you in January 2016!