DOCSLIB.ORG

Light-Emitting Diodes: Progress in Solid- State Lighting

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Light-Emitting Diodes: Progress in Solid- State Lighting www.mrs.org/publications/bulletin nologies. The MOCVD method can be used for the relatively cheap fabrication of so- phisticated layer structures with desirable bandgaps and optimized composition and Light-Emitting Diodes: doping profiles. These layered structures are the key element of electroluminescent chips. High rates of light-generation are achieved by confining the injected electrons Progress in Solid- and holes in double heterostructures and single or multiple quantum wells. Other layers are employed for contacts and cur- State Lighting rent spreading in the light-emitting layers. Another crucial issue for high-brightness LEDs is improving their light-extraction Artu¯ras Zˇukauskas, Michael S. Shur, efficiency. Providing for the efficient escape of photons from high-refractive-index and Remis Gaska materials used for light-generation is an important goal of LED chip design. The photons may escape only at incident angles smaller than the critical angle of the total Introduction internal reflection. This critical angle is ␪ ෇ Ϫ1 Until the beginning of the 19th century, problems of low light output and limited given by Snell’s law, c sin (ne/ns), flame produced by combustion was the color range that previously precluded where ne and ns are the refractive indices only source of artificial light. Since then, LED applications in lighting. The bright- of the encapsulating epoxy resin and the physical phenomena other than pyrolumi- ness, efficiency, and color choices of LEDs semiconductor, respectively. The solution nescence have been used to produce light.1 have achieved a level that is leading to widely used at present is to clad the light- Limelight (incandescence of calcium oxide dramatic changes in lighting technology. emitting layer with thick, transparent heated by the flame from an oxyhydrogen In this article, we review the present window layers.5,6 blowpipe), gas mantles (candoluminescence status of solid-state lighting, including dis- Figure 1 demonstrates the difference of gas-flame-heated rare-earth oxides), and cussions of the concept of high-brightness between a conventional LED and a high- the electrical Jablochkoff candle (an early LEDs, materials systems and chip design brightness LED. In a conventional LED type of carbon-arc lamp) were among the for monochrome LEDs, white LED lamps, (Figure 1a), light generated at a certain important milestones that led to modern and, finally, the emerging applications of point in the active layer may only escape lighting technology. In the 21st century, solid-state lighting. upward through a cone with an apex of ␪ most of the residential lighting worldwide A more detailed discussion of many is- 2 c. Almost all of the light emitted in other is provided by tungsten incandescent sues related to solid-state lighting may be directions is totally reflected and absorbed lamps. Compact fluorescent lamps are also found in our upcoming book.4 in the substrate and/or in the active layer. actively promoted because of their higher Ideally, the best performance would be performance—a broader spectrum for High-Brightness LEDs achieved in a spherical LED. In practical higher-quality white light and elimination The development of high-brightness planar high-brightness LEDs, thick window of 100–120-Hz flickering, for example. LEDs relied on the introduction of new layers allow the light to escape through six Most work environments employ fluores- semiconductors with efficiencies of visible cones (see Figure 1b). The thick window cent tubes for general lighting, and street emission much higher than those of early layers allow the light generated at the cen- lighting is dominated by sodium lamps.2 LED materials, such as GaAsP (red), GaP ter of the chip to escape through the lateral Lighting consumes ϳ2000 TWh of energy (yellow-green), and SiC (blue). Semicon- conical paths. Most commercial high- annually, about 21% of the global con- ductors used for high-brightness LEDs brightness LEDs exhibit light-extraction sumption of electricity.3 However, during must exhibit direct transitions with high efficiencies somewhat below 30%. In order the past 20 years, none of the conventional rates of radiative recombination, have to improve the light-extraction efficiency lighting technologies has exhibited a sig- wide bandgaps to emit at visible (or, in further, the LED design can employ non- nificant improvement in efficiency. The certain cases, UV) wavelengths, and pos- rectangular geometries,7 textured surfaces,8 drive to save lighting energy and reduce sess a low density of nonradiative re- and encapsulants with a higher refractive Ϸ its negative environmental impact (i.e., combination centers and high durability. index (at present, epoxy resins with ne 1.6 carbon emissions and the disposal of mer- Novel Group III–V direct-gap ternary and are used). cury contained in discharge lamps) stimu- quaternary compounds and alloys have Advanced solutions for the light- lates the search for new, efficient sources met these requirements. Practical high- extraction problem rely on photon-mode of light. brightness LEDs rely on three semiconduc- engineering. In order to inhibit the gen- This search focused attention on light- tor materials systems: AlGaAs, AlGaInP, eration of light in unfavorable directions, emitting diodes (LEDs), which, prior to and AlInGaN. microcavities,9 photonic crystals (i.e., struc- the last decade of the 20th century, were High-quality compound semiconductors tures with a periodic pattern of the refractive used only as indicator lamps and numerical became available as a result of advances index),10 and emitters with surface-plasmon displays in electronic devices. Today, ma- in epitaxy and especially heteroepitaxy enhancement11 have been introduced. ture methods for fabricating compound- technology. Vapor-phase epitaxy (VPE), semiconductor materials, progress in LED liquid-phase epitaxy (LPE), and metal- AlGaAs Red LEDs design, and the emergence of blue organic chemical vapor deposition The first high-brightness LEDs were de- AlInGaN-based LEDs have resolved the (MOCVD) have all become mature tech- signed for the red spectral region using 764 MRS BULLETIN/OCTOBER 2001 Downloaded from https://www.cambridge.org/core. University of Athens, on 01 Oct 2021 at 17:29:37, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/mrs2001.203 Light-Emitting Diodes: Progress in Solid-State Lighting grown by hydride VPE (HVPE) following MOCVD growth of an AlGaInP double heterostructure on the absorbing GaAs substrate. Then the absorbing GaAs sub- strate is removed from the grown hybrid AlGaInP/GaP structure using conven- tional selective chemical etching, and, fi- nally, a GaP wafer is fused to the revealed AlGaInP layer.16 The highest performances of AlGaInP/ GaP LEDs are achieved using chips that deviate from a conventional rectangular Figure 2. Typical chip structure for shape. A truncated inverted pyramid (TIP) a high-brightness AlGaAs double- shape, which is achieved by dicing a chip heterostructure LED chip using a with a beveled blade to yield side-wall transparent substrate (after Њ 7 Reference 12). angles of 35 with respect to the vertical, greatly improves light-extraction (Figure 3). Such a shape totally redirects internally the reflected photons at small incidence 10 lm/W, which is still three times higher angles that fit the escape cones. As of this than that of a red-filtered incandescent writing, the AlGaInP TIP LED holds the lamp. performance record for an electrolumines- Shifting the emission spectra toward cent visible-light source. In the orange shorter red wavelengths requires an active region (610 nm), it exhibits the highest layer with a wider bandgap and, hence, reported luminous efficiency, exceeding with a higher Al molar fraction. However, 100 lm/W (close to that of sodium lamps) increasing the Al content makes the direct- with a peak luminous flux of 60 lm. In gap and indirect-gap transitions closer, the red region (650 nm), external quantum which results in reduced performance. efficiencies of as high as 55% have been This makes it difficult to match the red achieved. Figure 1. (a) Schematic illustration color with the spectral sensitivity of the of the design of a conventional human eye. Another disadvantage of Blue, Green, and Amber light-emitting diode (LED) chip grown AlGaAs is its low corrosion resistance, on an absorbing substrate. Light InGaN LEDs escapes upward through a single cone which limits LED lifetime, especially under The InxGa1ϪxN alloy exhibits a direct conditions of increased temperature and with an apex of 2␪c. (b) High-brightness bandgap that varies from 1.89 eV to 3.4 eV, LED chip design with thick, transparent humidity. depending on the In molar fraction. This window layers. Light escapes through covers the spectral range from red to near- six cones. Red, Orange, and Yellow UV. At present, the AlInGaN system offers AlGaInP LEDs the most efficient LEDs in the blue to 17 The (AlxGa1Ϫx)0.5In0.5P alloy, which is green region. AlGaN/GaN/AlInGaN/ lattice-matched to GaAs and exhibits a InGaN-based blue LEDs are indispensable AlGaAs/GaAs materials.12 The main ad- direct bandgap in the range of 1.9–2.26 eV for the fabrication of white LEDs (see the vantage of the AlGaAs/GaAs system is (depending on the Al molar fraction), is next section). its very small lattice mismatch (GaAs and the most favorable material for red to yel- For many years, the development of AlAs differ in lattice constant by Ͻ0.2% at low high-brightness LEDs.13 The MOCVD Group III-nitride materials was hindered 25ЊC). This ensures the growth of high- growth of AlGaInP is a mature epitaxial by the lack of a suitable substrate. How- quality AlGaAs films on GaAs substrates. technique. Unfortunately, LPE and VPE ever, the pioneering work of Pankove, LPE can produce the thick, transparent methods, which are suitable for growing Akasaki, Nakamura, and many others led layers (having a sufficiently high Al con- thick window layers, are incompatible the way to the development of a mature tent) required for light-extraction through with the growth of AlGaInP alloys.
Load more

Recommended publications
  • The Electric-Lamp Industry
    Massachusetts Institute of Technology Studies of Innovation • GiSma,..=("EaEssormat THE MACMILLAN COMPANY THE ELECTRIC-LAMP INDUSTRY: NEW YORK a BOSTON a CHICAGO DALLAS • ATLANTA • SAN FRANCISCO MACMILLAN AND CO., LIMITED Technological Change and Economic LONDON a BOMBAY a CALCUTTA MADRAS a MELBOURNE Development from 1800 to 1947 THE MACMILLAN COMPANY OF CANADA, LIMITED TORONTO By ARTHUR A. BRIGHT, Jr. THE MACMILLAN COMPANY • NEW YORK 1949 FOREWORD THIS study of the economic development of the electric- lamp industry is the second volume in a series of studies on the economics of innovation, undertaken at the Massachusetts Insti- tute of Technology. The creative role played by science and technology in modern economic life is apparent to everyone. But we know relatively little about the human factors which condition the introduction of technological change into our environment. Are there barriers to innovation inherent in the increasing concentration of power in a few large concerns? Does the patent system, designed as an incentive to invention, act more often as a brake on new develop- ments? What has been the role of key personalities in creating change? Are there lessons to be drawn from the past on how the innovating process can be more effective, not only from the standpoint of achieving a higher standard of material being but from the point of view of smoother human relations? Certainly, material progress at any price is not a satisfactory goal. On the other hand, freedom for creative action in initiating and carrying out new developments is a basic human drive for many individu- als. I believe, personally, that a great society should strive toward a goal which will give to individuals and groups the maximum opportunities for creative expression; yet this means to me that the State must act to prevent the compulsive pressure of some particular group from overriding others to the destruction of human values.
    [Show full text]
  • A GLOSSARY of THEATRE TERMS © Peter D
    A GLOSSARY OF THEATRE TERMS © Peter D. Lathan 1996-1999 http://www.schoolshows.demon.co.uk/resources/technical/gloss1.htm Above the title In advertisements, when the performer's name appears before the title of the show or play. Reserved for the big stars! Amplifier Sound term. A piece of equipment which ampilifies or increases the sound captured by a microphone or replayed from record, CD or tape. Each loudspeaker needs a separate amplifier. Apron In a traditional theatre, the part of the stage which projects in front of the curtain. In many theatres this can be extended, sometimes by building out over the pit (qv). Assistant Director Assists the Director (qv) by taking notes on all moves and other decisions and keeping them together in one copy of the script (the Prompt Copy (qv)). In some companies this is done by the Stage Manager (qv), because there is no assistant. Assistant Stage Manager (ASM) Another name for stage crew (usually, in the professional theatre, also an understudy for one of the minor roles who is, in turn, also understudying a major role). The lowest rung on the professional theatre ladder. Auditorium The part of the theatre in which the audience sits. Also known as the House. Backing Flat A flat (qv) which stands behind a window or door in the set (qv). Banjo Not the musical instrument! A rail along which a curtain runs. Bar An aluminium pipe suspended over the stage on which lanterns are hung. Also the place where you will find actors after the show - the stage crew will still be working! Barn Door An arrangement of four metal leaves placed in front of the lenses of certain kinds of spotlight to control the shape of the light beam.
    [Show full text]
  • Fading Lights, Transitions in Theatre Lighting in a Historical Context
    Fading Lights Transitions in theatre lighting in a historical context by Chris Van Goethem (english revision by Gitta Van Goethem) Fading Lights is a cooperative project between the Expertise Center for Technical Theatre and the Stockholm Academy of Dramatic Arts. The project researches the history of lighting with a focus on the transitions between subsequent technologies. In the context of the im- minent transition to more LED sources, it seems useful to us to look at earlier transitions and maybe learn something from them. In other words, we would like to fnd out how the tech- nician, the designer, and the audience have adapted to the transition from candlelight to gas lights, to electrical lighting. The frst types of theatre were performed in daylight or with the lighting equipment that was at hand for domestic use. Those would have been torches, cressets, tapers, etc. In smaller spaces, dipped candles from animal fat were used among other things. Those were cheap, but gave off a conside- rable amount of smoke and stench. Apart from that, lamps based on a wick dipped in vegetable oil were used. Candles from bees wax were expensive en were therefore only used in extraordinary circumstances, when high-ranking people were present. The most important function of these sources of light was making the actors visible. Although we must also point out that some light sources 3 different types of cressets were manipulated by the actors so they could stress certain things. Some light sour- ces were also used purely symbolic to, for ex- ample, show that it was night, even though the play was during the day.
    [Show full text]
  • Gas Lighting Resources for Teachers
    Gas nationalgridgas.com/resources-teachers Gas Lighting Resources for teachers © National Gas Museum Using the resource National Grid owns, manages and operates the national gas transmission network in Great Britain, making gas available when and where it’s needed all over the country. This resource is part of our series for schools, highlighting and celebrating how gas has lit our homes and streets and kept us warm for over 200 years. This resource primarily supports History at Key Stages 1 and 2 and the development of children’s enquiry, creative and critical thinking skills. It includes: • Information for teachers • Fascinating Did you know..? facts • A series of historical images to help children explore the theme, with additional information and questions to help them look closer. It can be combined with other resources in the series to explore wider topics such as: • Energy • Homes • Victorians • Jobs and work • The industrial revolution • Technology And used to support cross-curricular work in English, Technology, Science and Art & Design. Project the images onto a whiteboard to look at them really closely, print them out, cut them up or add them to presentations, Word documents and other digital applications. Our Classroom activities resource provides hints, tips and ideas for looking more closely and using the images for curriculum-linked learning. Resources in the series • Gas lighting • Heating and cooking with gas Gas• Gas gadgets • Gas – how was it made? •How The changing role ofwas women It • Transport and vehicles • Classroom activities •made? Your local gas heritage A brief history of gas lighting – information for teachers Before the 1800s, most homes, workplaces and streets were lit by candles, oil lamps or rushlights (rush plants dried and dipped in grease or fat).
    [Show full text]
  • Enhanced Optical Efficiency and Color Purity for Organic Light
    www.nature.com/scientificreports OPEN Enhanced optical efciency and color purity for organic light-emitting diodes by fnely optimizing parameters of nanoscale low-refractive index grid Jae Geun Kim1,3, Yooji Hwang1,3, Ha Hwang1, Jun Hee Choi1, Young Wook Park 2* & Byeong-Kwon Ju1* To extract the confned waveguided light in organic light-emitting diodes (OLEDs), inserting a low refractive index (RI) periodic structure between the anode and organic layer has been widely investigated as a promising technology. However, the periodic-structure-based light extraction applied inside devices has been shown to severely distort spectrum and afect EL characteristics. In this study, a simple light extraction technology using periodic low-RI nanodot array (NDA) as internal light extraction layer has been demonstrated. The NDA was fabricated simply via laser interference lithography (LIL). The structural parameters of periodic pattern, distance, and height were easily controlled by the LIL process. From computational analysis using fnite-diference time-domain (FDTD) method, the NDA with 300 nm pitch and 0.3 coverage ratio per unit cell with 60 nm height showed the highest enhancement with spectral-distortion-minimized characteristics. Through both computational and experimental systematic analysis on the structural parameters of low-RI NDA-embedded OLEDs, highly efcient OLEDs have been fabricated. Finally, as representative indicators, hexagonal and rectangular positioned NDA-embedded OLEDs showed highly improved external quantum efciencies of 2.44 (+29.55%) and 2.77 (+57.38%), respectively. Furthermore, the disadvantage originating from the nanoscale surface roughness on the transparent conductive oxide was minimized. Screen, or display, has been acting as a connector between human being and electronic device for many decades.
    [Show full text]
  • The Autumn Issue
    the autumn issue trends transforming our homes guides to everything weatherboard-based looks get some lime in your life! the house that rocks enviro-friendly renovation tricks big showers & small sinks time-sensitive lighting wrangling the wow factor 08 16 26 38 08 wishlist 26 in profil 56 trend report: the future of design Autumn’s here and the season of indoor Architect Joshua Mulders is renowned for From lights that adjust their brightness depending on the time of socialising is upon us. Discover nine ways achieving great results while working within to delight your dinner party guests. strict environmental and heritage constraints. day to bathrooms that have been reimagined as social hubs, the times they are a’changing. Drawing on insights from those working 14 despatches 36 steal that idea at the coalface, we explore the trends that are set to transform the Whether it’s to install a kitchen cabinet, Emerald may no longer be the Colour of the way you design, decorate and inhabit your home in the near future . make a small space seem larger or minimise Year but we’re still keen on green. See what a renovation stress, we’ve got the guide for you. lick of luscious lime can do to a bay window. 16 get the look on the cover Balmain House by Joshua Mulders Architects. managing editor Amanda Falconer. editor Nigel Bowen. art director Elinor 38 design spotlight McDonald. contributors Andrea Sophocleous, Rachel Sullivan, Peta Newbold. videographer & editor Victor Rodriguez. letters to With some sophisticated weatherboard and a Eco-conscious, spectacular and affordable – [email protected].
    [Show full text]
  • Ariel Davis : Utah Innovator
    Brigham Young University BYU ScholarsArchive Faculty Publications 2003 Illuminating Theatre / Ariel Davis : Utah Innovator J. Michael Hunter Brigham Young University - Provo, [email protected] Follow this and additional works at: https://scholarsarchive.byu.edu/facpub Part of the Mormon Studies Commons, and the Theatre and Performance Studies Commons BYU ScholarsArchive Citation Hunter, J. Michael, "Illuminating Theatre / Ariel Davis : Utah Innovator" (2003). Faculty Publications. 1406. https://scholarsarchive.byu.edu/facpub/1406 This Other is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Faculty Publications by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. -- ~ -... --- Notes horses and could seat 40 children. field of elocution. 11 H er fa mily was so li vid While in U tah, Julia met James G. over her religious conve rsion that her mother I Jane Edwards, "Maud Adams' Cooper, Secretary of the Territory of Utah, said she would rather Maud May had had a Magic," Salt Lake Tribune, whom she married at the end of her Salt child out of wedlock and that she hoped her Jan. 5, 1997, j - 1. Lake stage experi ence in 1866. The Coopers tongue would be paralyzed if she publicly By]. M ich ae l H un t er 2 Edwards, j - 3. then left U tah fo r the East, but within a year defended the church.12 3 "Death of Maude Adams, Julia died during childbirth. Peti te in size ( 5'4") but strong in will End of Brilliant Stage Era," t was late one afternoon in the Daughters of Utah Pioneers and body, Maud May didn't simply come to archive, 1953.
    [Show full text]
  • Mexicoindians Armtod^End Their^Diines Evangelist To
    . .,v ,, ,^ • ■ •• - ' "•,' ,-■ ■ r ' - -' ISBT PRESS RUN AVERAGE DAILE CIRCULATION OF TUB EVENING HERALD for tbo month of Jnnoi 1926> 4,837 (EIGHTEEN PAGES) MANCHESTER, CONN., FRIDAY, JULY 30, 1926. VOL. XLIV., NO. 256. CUuMifled Advertising on Page 0 <5> * POPE BANS PROTESTANTS In the Midst of Florida Hurricane AT GENERAL AUDIENCES EVANGELIST TO London, . July 30.— Mayfair '■ + - ♦ : MEXICOINDIANS Rome, July 30.— Regulations women are nothing if not meti- forbidding the admission of culqus. Protestants to general audiences FACE INQUIRY Bare legs have again come ARMTOD^END with the Pope were put in effect Into fashion. Colored powders today by Vatican officials, as the to match the gown are used on result of the incident yesterday the bare legs and a thin line is when a British Protestant re­ ASTO^MRY painted down the back of the THEIR^DIINES fused to kneel during an audi­ leg to simulte the seam of the ence, as the Pope passed. stocking. Fifty Protestants were today Decides to Appoint Special denied audiences with the Pope, Aimee McPherson Is Sub­ Crisis in Conflict of Chnrch despite the fact that many of Deputy Attorney-General; them had been sponsored by the poenaed to Confront Wit­ TIG WOMAN’ WILL and State Due at Ifid- American College. Bergen Fights Release of nesses from Carmel Who ‘STICK TO TRUTH’ night When Clergy ESTATES MELT IN Prisoner on BaO. t Abandon Edifices. May Identify Her. Jane Gibson Declares She Is Trenton, N, J., July 80.— Got* BANKRUPTS’ COURT Los Angeles, July 30.— Aimee Hurricane gales were lashing the photographer as w cll as the palm trees when this picture of Miami's ernor Moore today decided that a Mexico City, July 30.
    [Show full text]
  • A Brief Outline of the History of Stage Lighting
    A Brief History of Stage Lighting Página 1 de 13 A Brief Outline of the History of Stage Lighting Reference: Bel Geddes, Norman. Miracle in the Evening . Garden City, NY: Double Day and Co., Inc. 1960 Bergman, Gosta Mauri. Lighting in the Theatre . Stockholm: Almqvist & Wiksell International. 1977 Fuchs, Theodore. Stage Lighting. New York: B. Blum. 1963 (1929) Hartman, Louis. Theatre Lighting: A Manual of the Stage Switchboard . New York: DBS Publications. 1970 (1930) Owen, Bobbi. Lighting Designers on Broadway: 1915-1990 . New York: Greenwood Press. 1991. Owens, Bobbi. Scene Designers on Broadway . New York: Greenwood Press. 1991. Pendleton, Ralph. The Theatre of Robert Edmond Jones . Middletown, CT. Wesleyan University Press. 1958 On the Internet: Kliegl Bros.Collector's Society Lighting Equipment - Lighting Designers - Lighting Educators - Time Line: 1880... Lighting Equipment General Illumination: Candle - Oil Lamp - Gas - Electric Specific Illumination: Lime Light - Arc Light - Electric Spotlight General Illumination General illumination provides a diffuse, shadow less, wash of light over the entire stage space. Candle Italy - 1580-1618: Candles are introduced in both the academic ( Teatro Olimpico ) and court ( Teatro Farnese ) theatres. England - 1600s: Used in the private (indoor) theatres and Ingo Jones' (1573-1652) Court Masques . 1660s: Reintroduced during the English Restoration. Mounting Positions: Chandeliers over both the stage and the house, Front edge of the stage (footlights), and "Ladders" between each pair of side wings. Oil Lamp 1780s: Swiss chemist Aime Argand develops the modern oil lamp which soon replaces the candle as the primary light source. Mounting Positions: The same as with candles-- Chandeliers , Foot lights , and Ladders in the wings.
    [Show full text]
  • Historical Perspective on the Physics of Artificial
    C. R. Physique 19 (2018) 89–112 Contents lists available at ScienceDirect Comptes Rendus Physique www.sciencedirect.com LEDs: the new revolution in lighting / Les LED : la nouvelle révolution de l’éclairage Historical perspective on the physics of artificial lighting Perspective historique sur la physique de l’éclairage Claude Weisbuch a,b a Materials Department, University of California at Santa Barbara, USA b Laboratoire de physique de la matière condensée, CNRS, École polytechnique, Palaiseau, France a r t i c l e i n f o a b s t r a c t Article history: We describe the evolution of lighting technologies used throughout the ages, and how Available online 21 March 2018 the need for improvements was such that any new technology giving better and cheaper lighting was immediately implemented. Thus, every revolution in energy sources – gas, Keywords: petrol electricity – was first put to large-scale use in lighting. We describe in some detail Lighting several “ancient” techniques of scientific interest, along with their physical limitations. Light-emitting diodes Electroluminescence – the phenomenon by which LEDs directly convert electricity into Gas mantle Lamps light – was long thought to only be of use for indicators or flat panel displays supposed to Light sources replace the bulky cathode-ray tubes. The more recent uses of LEDs were mainly for street traffic lights, car indicators, small phone displays, followed by backlighting of TV screens. Mots-clés : LED lamps for general lighting only emerged recently as the dominant application of LEDs Éclairage thanks to dramatic decrease in cost, and continuous improvements of color quality and Diodes électroluminescentes energy conversion efficiency.
    [Show full text]
  • Glossary of Combustion
    Glossary of Combustion Maximilian Lackner Download free books at Maximilian Lackner Glossary of Combustion 2 Download free eBooks at bookboon.com Glossary of Combustion 2nd edition © 2014 Maximilian Lackner & bookboon.com ISBN 978-87-403-0637-8 3 Download free eBooks at bookboon.com Glossary of Combustion Contents Contents Preface 5 1 Glossary of Combustion 6 2 Books 263 3 Papers 273 4 Standards, Patents and Weblinks 280 5 Further books by the author 288 4 Click on the ad to read more Download free eBooks at bookboon.com Glossary of Combustion Preface Preface Dear Reader, In this glossary, more than 2,500 terms from combustion and related fields are described. Many of them come with a reference so that the interested reader can go deeper. The terms are translated into the Hungarian, German, and Slovak language, as Central and Eastern Europe is a growing community very much engaged in combustion activities. Relevant expressions were selected, ranging from laboratory applications to large-scale boilers, from experimental research such as spectroscopy to computer simulations, and from fundamentals to novel developments such as CO2 sequestration and polygeneration. Thereby, students, scientists, technicians and engineers will benefit from this book, which can serve as a handy aid both for academic researchers and practitioners in the field. This book is the 2nd edition. The first edition was written by the author together with Harald Holzapfel, Tomás Suchý, Pál Szentannai and Franz Winter in 2009. The publisher was ProcessEng Engineering GmbH (ISBN: 978-3902655011). Their contribution is acknowledged. Recommended textbook on combustion: Maximilian Lackner, Árpád B.
    [Show full text]
  • Solid State Lighting
    Solid State Lighting Michael Shur Rensselaer Polytechnic Institute ECSE, Physics and Broadband Center http://nina.ecse.rpi.edu/shur From a Torch to Blue and White LEDs and to Solid State Lamps Blue LED on Si, Courtesy of SET, Inc. http://nina.ecse.rpi.edu/shur/ 1 Research Areas • Plasma wave electronics –THz resonant emission and detection • Wide band gap materials and devices – MOSHFET, UV LEDs, SAW, polarization, transport • Sensitive skin – Flexible substrates, nano gauges, electrotextiles, TFTs, OTFTs • Novel device CAD – AIM-Spice, opto/thermo/micro CAD •Lab-on-the-WEB – http://nina.ecse.rpi.edu/shur/remote • Broadband center http://nina.ecse.rpi.edu/shur • Solid state lighting http://nina.ecse.rpi.edu/shur/ 2 Talk Outline • History of General and Electric Lighting • Advantages of Solid State Lighting • Introduction to Photometry and Colorimetry • Optimization of Solid State Lamps • Emerging applications • Vision http://nina.ecse.rpi.edu/shur/ 3 Lighting – prerequisite of human civilization • 500,000 years ago- first torch • 70,000 years ago – first lamp (wick) • 1,000 BC – the first candle • 1772 - gas lighting Yablochkov candle (1876) • 1784 Agrand lamp - Agrand lamp the first lamp relied on research (Lavoisier) • 1826 -Limelight - solid- state lighting device • 1876 – Yablochkov candle • 1879 – Edison bulb Limelight Edison bulb (1879) http://nina.ecse.rpi.edu/shur/ 4 History of Electric Lighting • 1876 Pavel Yablochkov. First electric lighting device • 1879 Thomas Alva Edison. Incandescent lamp • 1897 Nernst. Filament made of cerium oxide-based solid electrolyte. • 1900 Peter Cooper Hewitt. Mercury vapor lamp. 1903. A. Just and F. Hanaman. Tungsten filament • 1904 Moor. Discharge lamps with air • 1907 H.
    [Show full text]