Technology | Products, Materials & Tools | Dec 09, 2016

LRC Releases Free, Open Access Circadian Stimulus Calculator

LRC Releases Free, Open Access Circadian Stimulus Calculator The Lighting Research Center (LRC) at Rensselaer Polytechnic Institute has recently released a free, open-access circadian stimulus (CS) calculator to help lighting professionals select light sources and light levels that will increase the potential for circadian-effective light exposure in architectural spaces, utilizing the CS metric. Developed by LRC researchers, the CS metric is a new way to quantify light’s impact on acute melatonin suppression, a marker of circadian system activation. Read more »

Technology | May 20, 2016

LED Lighting: All Eyes on Flicker by Tridonic

LED Lighting: All Eyes on Flicker by Tridonic Flicker was a familiar problem with early fluorescent lamps. However, increasingly powerful electronic control gear has largely offset these interferences over time, banishing them from current perception. Since LEDs (light-emitting diodes) have become established in all areas of lighting, including general lighting, flicker has reemerged. LED Drivers play a key role in producing light that is as flicker-free as possible. Read more »

Technology | Sep 08, 2015

Background Information on the Luxeon C LED Family from Lumileds

All four Luxeon C LEDs shown are based on very different technologies, but they have a common identical focal length and low-dome design to prevent cross-talk In an exclusive interview, Rahul Bammi, Vice President of Marketing & Product Management at Lumileds, and David Cosenza, Product Manager for the Luxeon Color LED Family, disclosed some background information on why this new product family was designed and why the very specific, new, and unique properties were implemented. Read more »

Technology | Aug 21, 2015

Researchers Propose New Technology without Rare Earth Metals for LED Lighting

An LED coated with a yellow “phosphor” is shown turned off (left) and then turned on (right). This “green” LED is inexpensive and provides warm white light (Credit: Zhichao Hu, Ph.D.) At the 250th meeting of the American Chemical Society a novel approach to generate white light without using rare earth metals was presented. The reaserachers claim that this approach will lead to cheaper warm white LEDs than the currently used technologies. A press conference on this topic was held on Wednesday, Aug. 19, at 9 a.m. Eastern time in the Boston Convention & Exhibition Center. Read more »

Technology | Aug 20, 2015

Researchers from Oregon State University Develop Quantum Dot Technology that may Help Light the Future

The orange color in the letters “OSU” is produced from “quantum dots” viewed under a microscope, as they absorb blue light and emit the light as orange – an illustration of some of the potential of new technology being developed at Oregon State University. (Image courtesy of Oregon State University) Advances at Oregon State University in manufacturing technology for quantum dots may soon lead to a new generation of LED lighting that produces a more user-friendly white light, while using less toxic materials and low-cost manufacturing processes that take advantage of simple microwave heating. Read more »

White Paper | Technology | Jul 21, 2015

Litecool Demonstrates that Narrow Beam LED Packages Are a Real Possibility

Litecool have shown promising results for new LED package design that gives focused light beams with no secondary optics or reflectors Litecool has been working on various LED package designs to give luminaire manufacturers an LED package that doesn’t need any further lensing or reflectors to give the desired beam patterns for lighting applications. Read more »

White Paper | Technology | May 27, 2015

BluGlass Demonstrates Improved Performance Results for Green RPCVD Manufactured p-GaN LEDs

Green light emission from RPCVD p-GaN layers grown on MOCVD MQWs BluGlass has succeeded in its initial experimentation of applying low temperature RPCVD p-GaN to Green LED applications with highly promising results. These results show that the green LEDs produced using RPCVD p-GaN are demonstrating greater efficiency than the BluGlass grown MOCVD benchmark LEDs using the exact same MOCVD grown multi-quantum wells (MQWs), the critical light emitting region of an LED device. Read more »

Technology | May 04, 2015

Configuration Via the Mains: Simple, Reliable and Professional

Figure 1: The ready2mains programmer makes the configuration of the ready2mains drivers an easy task As the heart of any LED luminaire, the LED driver not only has to meet strict requirements in terms of quality and reliability but also be flexible enough to adapt to different conditions. ready2mains – a new technology from Tridonic – helps enormously. The article explains what is needed and how it works. Read more »

White Paper | Technology | Mar 30, 2015

TRIAC Dimmable, Isolated LED Driver with High Power Factor Needs No Opto-Isolators

TRIAC Dimmable 20W Offline LED Driver Using the LT3799 As environmental concerns over traditional lighting in-crease and the price of LEDs decreases, high power LEDs are fast becoming a popular lighting solution for offline applications. In order to meet the requirements of offline lighting - such as high power factor, high efficiency, isolation and TRIAC dimmer compatibility - prior LED drivers used many external discrete components, resulting in cumbersome solutions. By Wei Gu Applications Engineering Section Leader at Linear Technology demonstrates how new solutions reduce complexity while improving performance. Read more »

White Paper | Technology | 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 »

White Paper | Technology | 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 further boost in efficiency. Read more »

White Paper | Technology | 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 »

White Paper | Technology | 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 finding a permanent solution that is more suitable for people’s well-being. - Andy Fei and Nina Chen from ALT-LED summarize these flicker research results and explain how to avoid flicker issues. Read more »

White Paper | Technology | 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 »

White Paper | Technology | 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 »

FEATURED

Smart High-Power LED Driver from Lifud

Smart High-Power LED Driver from Lifud As a pioneer in the LED industry who dared to break away from conventions and apply non-isolated design to the LED driver for UFO high bay driver, Lifud has done a good job referring to the sales records and customer feedback of the LF-FHBxxxYx series. Read more »

FEATURED

Cree Launches Industry’s Highest Efficacy 90 CRI COB LEDs

Cree Launches Industry’s Highest Efficacy 90 CRI COB LEDs Cree, Inc. announces the XLamp® eTone™ LEDs, a breakthrough set of chip-on-board (COB) LEDs that delivers beautiful 90 color rendering index (CRI) light quality at the same efficacy as today’s standard 80 CRI LEDs. Delivering up to 155 lumens per watt (LPW) at 3000 K CCT, 85°C, Cree’s new eTone COB ... Read more »

EDITORIAL

High Conductive Foils Enabling Large Area Lighting

High Conductive Foils Enabling Large Area Lighting Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP as one of the leading partners for research and development for surface technologies and organic electronics and Sefar AG, a leading manufacturer of precision fabrics from monofilaments, developed a roll-to-roll ... Read more »

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