Technology | OLEDs | Mar 17, 2015

Fraunhofer FEP Presented Transparent Color Tunable OLED

The color tunable OLED modules have a diameter of 55 mm with an active light area of 42 mm The project LOIGB (LED and OLED integration into glass and plastic composites for the use in lighting systems for railway and further applications) has been successfully completed. The results were presented at LOPEC 2015 (March 4th – 5th, 2015, Munich, hall B0, booth 230). Read more »

Technology | Light Generation | White Paper | Technology | Electronics | Feb 17, 2015

The Future of More Efficient LEDs and Lasers Probably Starts in 2D

Researchers at The Ohio State University have developed a technique for making one-atom-thick sheets of germanium for eventual use in advanced electronics. Already in 2010, MIT's Material Research Group demonstrated the first germanium laser (Photo: Dominick Reuter/MIT) The future of electronics could lie in a material from its past, as researchers from The Ohio State University work to turn germanium - the material of 1940s transistors - into a potential replacement for silicon. Read more »

Technology | Light Generation | White Paper | Feb 16, 2015

Osram Improves Efficiency of Blue LED Chips by Reducing Forward Voltage

Osram experts have significantly reduced the value of the forward voltage, compared with the data sheet for the previous Osram Oslon Square Osram Opto Semiconductors has achieved one of the best values in the world in terms of forward voltage for blue high-current chips. This has led to an increase in efficiency of up to eight percent. Optimized InGaN chips (Indium-Gallium-Nitride) featuring UX:3 chip technology are the basis for blue or white LEDs – and are already used in production. Osram experts also see considerable potential for reducing the value by a further 20 to 30 millivolts (mV) by the summer of 2015 – offering a ... Read more »

Technology | Light Generation | White Paper | Feb 05, 2015

Universities Develop Novel LEDs by Band-Structure Engineering in van der Waals Heterostructures

Schematic of the SQW heterostructure for graphene based, band-structure engineered LEDs Semi-transparent, flexible electronics are no longer just science-fiction thanks to graphene’s unique properties, University of Manchester researchers have found. Published in the scientific journal Nature Materials, University of Manchester and University of Sheffield researchers show that new 2D ‘designer materials’ can be produced to create flexible, see-through and more efficient electronic devices including semi-transparent LEDs. Read more »

Technology | OLEDs | White Paper | Jan 15, 2015

Holst Centre and Flex-o-Fab Take the First Step Towards "Lighting by the Mile"

Manufacturing flexible OLEDs using a R2R-process is crucial for reducing costs for coming down to an affordable price Researchers from the EU-funded Flex-o-Fab project have successfully fabricated working OLED devices on a flexible barrier layer produced in a roll-to-roll (R2R) process. Produced on a PET plastic film, this breakthrough is a significant first step towards taking flexible OLEDs ‘from lab to fab’ and hence to commercial production. It draws on technical developments achieved within both Flex-o-Fab and Holst Centre’s joint research program into high-performance flexible barriers for organic ... Read more »

Technology | Light Perception | White Paper | Jan 15, 2015

Ending the Invisible Threat - Confronting the LED Flickering Issue

Figure 5: The flicker comparison of lighting products (Sources: Michael Poplawski and Naomi Miller, ”SSL Flicker Fundamentals and Why We Care” - U.S Department of Energy, 2014) One of the topics in 2014 International LIGHTFAIR DOE training was “SSL Flicker Fundamentals and Why We Care“ (Michael Poplawski and Naomi Miller 2014),this reignited the industry’s discussion on light modulation. This topic was already raised by ASSIST earlier, where research on human’s level of tolerance to high-frequency flickers have been done and published in several lighting magazines by Rebekah Mullaney, hoping to encourage LED manufacturers and distributors to put more emphasis on ... Read more »

White Paper | Technology | Binning | Jan 09, 2015

LpS 2014 Scientific Award Winner Article: New Binning Strategy for White LEDs

Figure 1: Semantic contours for chromaticity differences from the chromaticity center in the CIE x,y chromaticity diagram for a warm white chromaticity center, the Planckian radiator at 2500 K; x=0.4770; y=0.4137 (light green dot). Going off the center in any direction, contours indicate “good-very good” (green contour), “good” (yellow contour), “moderate-good” (orange contour), “low” (red contour) and “bad” (lilac contour) perceived color agreement with the center. Contours of constant chromaticity differences (Δu’v’=0.001 - Δu’v’=0.007 i.e. approximations of MacAdam ellipses) measured from the chromaticity center are also shown After having recognized the deficiencies of the ANSI binning strategy, which is based on the visually false magnification of MacAdam’s ellipses, Dr. Peter Bodrogi and Prof. Tran Quoc Khanh from the Technical University Darmstadt propose a new binning strategy based on a so-called semantic interpretation to describe and easily communicate the magnitude of acceptable chromaticity differences. Read more »

Technology | Light Generation | White Paper | Jan 09, 2015

Compute Simulation Sheds Light On Why Blue LEDs Are So Tricky To Make

New research from academics from the University of Bath Department of Chemistry has uncovered the mystery of why blue light-emitting diodes (LEDs) are so difficult to make: (1) Calculated spin density resulting from (a) a Mg0Ga-associated hole localized on a neighboring N in the basal plane, (b) a Mg0Ga-associated hole localized on a neighboring axial N, and (c) a N vacancy. Light gray (green) [darker gray (blue)] spheres represent Ga (N) atoms. The darkest gray sphere represents a Mg atom in (a) and (b) (purple) and a vacancy in (c) (orange). Spin densities are indicated by (red) isosurfaces of density (au) 0.05, 0.025, and 0.01 for (a) and (b) and 0.01, 0.005, 0.0025 for (c). (2) Formation energy of VN (black line) and MgGa [light gray (red) line] as a function of Fermi energy above the VBM. Anion-rich conditions are assumed. The position of the conduction band minimum (CBM) is indicated by the broken line. For each value of Fermi energy, only the most stable defect charge state is shown, with a change in slope indicating a change in charge state Researchers in our Department of Chemistry have collaborated with groups at University College London (UCL) and Daresbury to uncover the mystery of why blue light-emitting diodes (LEDs) are so difficult to make, by revealing the complex properties of their main component – gallium nitride – using sophisticated computer simulations. Read more »

Products | UV-LEDs

Recipients of the Nobel Prize in Physics Support the Development of Deep-UV LEDs

The first presentation of the new deep-UV LEDs that were supported by Profs. Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura, has been at electronica 2014 in Munich Profs. Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura received the Nobel Prize in physics in mid-December 2014 for their breakthrough that enabled the development of blue LEDs. In particular, Professor Amano and his team at Nagoya University have worked intensively over the past few years on further development of these semiconductor-based lamps. They provided consulting services to the Japanese firm of Nikkiso Co. Ltd. in the design of the first deep-ultraviolet light-emitting diodes ... Read more »

Technology | Light Generation | White Paper | Nov 21, 2014

Thermoresponsive PDLC Coating for Smart CCT-Tunable LED Applications

Thermoresponsive scattering coating for smart CCT-changing white LEDs: a) basic working mechanism; b) demonstrator using coated (bottom) and uncoated (top) warm white LEDs operating at a low current (~20 mA/LED - top picture) and at a high current (~80 mA/LED - the bottom); c) associated CCT vs. current diagram When the 2014 Nobel Prize in physics was awarded this October to three Japanese-born scientists for the invention of blue light emitting diodes (LEDs), the prize committee declared LED lamps would light the 21st century. Now researchers from the Netherlands propose a novel way to ensure the lights of the future not only are energy efficient but also emit a cozy warmth. Cornelissen and his colleagues from the Eindhoven University of Technology, Netherlands describe their new LEDs in a paper ... Read more »

Technology | Light Generation | Nov 06, 2014

Osram Reports Record Figures for Green InGaN-Based and Conversion LEDs

LEDs show a significant efficacy drop in the green spectral range – an effect known as the “green gap” phenomenon The “Hi-Q-LED” project funded by Germany’s Federal Ministry of Education and Research (BMBF) has made pioneering advances with green LEDs, greatly diminishing what is known as the “green gap” phenomenon – the significant drop in efficacy in the green spectral range. The result is a green-emitting LED based on indium gallium nitride (InGaN) semiconductors which achieves a record efficacy of 147 lumens per watt (lm/W) at a wavelength of 530 nanometers (nm) and a spectral width of 35 nm. In ... Read more »

Technology | OLEDs | Nov 03, 2014

Light in New Shape - BMBF-Funded Joint Project R2D2

The reserach progresses of the last five years have proven the technical feasibility of transparent light sources with very low energy consumption, which furthermore can be applied to flexible and pliable substrates The research progresses of the last five years have proven the technical feasibility of the vision of a transparent and flexible light sources with very low energy consumption in the form of first demonstrators. Now the BMBF-funded joint project R2D2 will start in November 2014 aiming at the investigation of production-related processes and technologies for the manufacturing of flexible OLED. Read more »

Technology | Light Generation | Oct 07, 2014

And the Nobel Price 2014 Goes To ... The Inventors of the Blue LED

The blue LEDs, invented by the winners, are the basis for today's white LEDs like - following the latest trend - these chip-LEDs The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics for 2014 to Isamu Akasaki from the Meijo University, Nagoya, Japan and Nagoya University, Japan, to Hiroshi Amano from the Nagoya University, Japan and to Shuji Nakamura from the University of California, Santa Barbara, CA, USA for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources. Read more »

Technology | Light Generation | Sep 25, 2014

Nanotechnology May Lead to Better, Cheaper LEDs

(a) Princeton researchers have used their expertise in nanotechnology to develop an economical new system that markedly increases the brightness, efficiency and clarity of LEDs, which are widely used in smartphones and other electronics. The illustration demonstrates how a conventional LED's structure traps most of the light generated inside the device; the new system, called PlaCSH, guides the light out of the LED. (lllustration courtesy of Stephen Chou et al.) (b) PlaCSH has a layer of light-emitting material about 100 nanometers thick that is placed inside a cavity with one surface made of a thin metal film (shown at left.) The key part of the device is a metal mesh (center) with incredibly small dimensions: it is 15 nanometers thick; and each wire is about 20 nanometers in width and 200 nanometers apart from center to center. An image of the experimental LED is shown at right. (Images courtesy of Stephen Chou et al.) Princeton University researchers have developed a new method to increase the brightness, efficiency and clarity of LEDs, which are widely used on smartphones and portable electronics as well as becoming increasingly common in lighting. Using a new nanoscale structure, the researchers, led by electrical engineering professor Stephen Chou, increased the brightness and efficiency of LEDs made of organic materials (flexible carbon-based sheets) by 57 percent. The researchers also report their ... Read more »

Technology | Light Perception | Sep 18, 2014

LpR 44 Article: Discomfort Glare Perception of Non-Uniform Light Sources in an Office Setting

Test setup of the different regions and luminance patterns under test LED based luminaires with different luminance patterns and recently with increasingly non-uniform luminance patterns are becoming mainstream. This trend makes discomfort due to glare an important topic. Based on an office setting and the comparison of results from three different regions, L. M. Geerdinck, J. R. Van Gheluwe and M.C.J.M. Vissenberg from Philips Research have reviewed the currently used formulae to predict discomfort glare to ascertain if they are still valid. Read more »

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