White Papers
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](https://www.led-professional.com/technology/light-generation/compute-simulation-sheds-light-on-why-blue-leds-are-so-tricky-to-make/University%20of%20Bath%20Department%20of%20Chemistry%20has%20uncovered%20the%20mystery%20of%20why%20blue%20light-emitting%20diodes%20-LEDs-%20are%20so%20difficult%20to%20make.jpg/@@images/dd63b2df-d470-4f03-8bb0-9457a16f63d6.jpeg "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.
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Zhaga Consortium Starts Work on New Specification for COB LED Arrays
In response to feedback from a broad range of stakeholders, the Zhaga Consortium, which develops specifications for
interchangeable LED light sources, is now working on a new Book that will include Chip-on-Board (COB) LED arrays. The new Zhaga Book will specify a family of six rectangular or square LED modules with different dimensions.
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Thermoresponsive PDLC Coating for Smart CCT-Tunable LED Applications
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 published in The Optical Society's (OSA) open-access journal Optics Express.
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WHITE PAPER: "Optimization of LED Lens Components using TracePro® Illumination Design and Analysis Software"
TracePro® is award-winning opto-mechanical design software for layout, optimization, & analysis of illumination systems. This white paper illustrates how TracePro’s 2D & 3D optimization utilities are designed to help CAD designers without optical engineering expertise design a variety of LED optical components – including practical examples. The capabilities of TracePro lead the designer through a process to maximize the technical merits of the device/system in the shortest amount of time.
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WHITE PAPER: Intelligent Over Temperature Protection for LED Lighting Applications
LED lighting is becoming increasingly popular. It offers numerous advantages over conventional lighting, but there are still some issues. One is thermal management. Bernd Pflaum and Hakan Yilmazer from Infineon Technologies explain how LED driver ICs with smart over temperature protection help to increase lifetime and optimize system costs of LED lighting systems.
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Osram Opto Demonstrates "3D nano LEDs" for White Light and Sees Series Maturity in Coming Years
By making use of nanotechnology, Osram hopes to produce significantly more LED chips with its existing production plant. Osram researchers have for the first time succeeded in manufacturing a so-called "3D nano LED" for white light. The productivity boost is possible due to the special surface characteristics of the LED chip – in contrast to today's standard models, this is not smooth but consists of many adjacent, microscopically small columns with a three-dimensional structure, thus increasing its light-generating area. The new technology is expected to achieve series maturity in coming years, and Osram would then be one of the first companies to use this technology.
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Yole Releases New Nanowire LED IP Study - Startups Compete with Asian LED Giants in the IP Landscape
Asian giants Samsung, Panasonic and LG are the top three patent assignees for Nanowire LED technology. Facing them are several startups including glo, Aledia and Ecospark, which between them have raised more than $150M - thus confirming their serious interest in this field. However, these newcomers face strong technological challenges.
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GaN-on-Silicon Substrate Patent Investigation - Knowmade & Yole See More Players on the Playground
GaN-on-Si technology appeared naturally as an alternative to GaN-on-Sapphire—the main stream technology for LED applications. Today, despite potential cost benefits, the mass adoption of GaN-on-Si technology for LED applications remains unclear. Most major LED makers have a patenting activity related to GaN-on-Si technology, but so far, few have made it the core of their strategy and technology roadmap. Contrary to the LED industry, we expect GaN-on-Si to be widely adopted by Power Electronics and RF applications because of its lower cost and CMOS compatibility.
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EEPCA & LightingEurope Announce ENEC+ - The First European Mark That Certifies the Initial Performance of LEDs and Other Luminaires
EEPCA, the European Electrical Products Certification Association, in cooperation with LightingEurope, today announced the launch of ENEC+, the first pan-European mark capable of certifying the initial performance of traditional and LED luminaires. The new performance rating provides the market with certification as to the compliance of LED light fixtures and other luminaires, proving compliance with European safety standards and ensuring the reliability of their stated performance characteristics at the beginning of their life cycle.
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Zhaga Starts Work on New Books
The Zhaga Consortium, a global lighting-industry organization that is enabling interchangeable LED light engines, has started the development of three new interface specifications, known as Books. The new Books are designated numbers 9, 10 and 11.
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Yole Développement's GaN-on-Si Report Forecasts Future of power Electronics and LEDs
Yole Développement releases this week the GaN-on-Si Substrate Technology and Market for LED and Power Electronics report. Under this report, Yole Développement reviews the GaN-on-Si technology growth, challenges and solutions. Dr Hong Lin and Dr Eric Virey, Yole Développement’s analysts give an overview of GaN-on-Si epiwafer playground. This report also provides an in-depth analysis of the GaN-on-Si technology for LED and power electronic applications, including technology and cost aspect. Yole Développement’s analysts, both develop possible business models for the adoption of GaN-on-Si technology. GaN-on-Si substrate technology and market for LED and Power Electronics report also includes market volume and revenue forecast to 2020.
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Zhaga Aims to Enable Independent Interchangeability of LED Modules and Drivers
The Zhaga Consortium, which develops specifications for interchangeable LED light engines, has decided that it will also aim to enable LED modules and drivers that are independently interchangeable. This is in addition to Zhaga’s stated aim to enable interchangeability of LED light engines.
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Quantum Materials Secures Los Alamos Thick-Shell Quantum Dot Technology to Increase Brightness
Quantum Materials Corporation and Los Alamos National Laboratory's today announce Quantum Materials optioning Thick-Shell 'Giant' Quantum Dot patented technology with the potential of 10 to 100-fold improvement in solid-state brightness over conventional nanocrystal quantum dots (QD). High brightness leads to efficient use of materials and increased performance in electronic displays and solid state (LED) lighting.
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New Research Initiative: LASSIE-FP7 To Develop LED-Based Modules for Professional and Architectural Lighting
CSEM announces the launch of LASSIE-FP7, a research project funded by the European Commission to develop a unique integrated solid-state module that will constitute a breakthrough in professional and architectural lighting. Read more »
CPI Manufactures Flexible OLED Lighting Demonstrators
The Centre for Process Innovation (CPI) has produced a range of flexible Organic Light Emitting Diode (OLED) demonstrators. Manufactured on CPI’s OLED/OPV Prototyping Line, the devices have been built on a range of substrates with thickness ranging from 50µm to 125µm. The device structure consists of an Indium Tin Oxide anode, evaporated hole injection layer, co-evaporated emissive layer and a conventional cathode. The device chemistry can be modified to produce a variety of colours and is encapsulated using a pressure sensitive adhesive and a commercially available barrier material.
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WHITE PAPER: "LED Reflector and Lens Simulation using TracePro® Illumination Design and Analysis Software"
TracePro® is award-winning opto-mechanical design software for layout, optimization, & analysis of illumination systems. This white paper illustrates how TracePro allows users to begin a project with an initial or basic design for LED lighting systems, use software simulation prior to building hardware, and easily create complex reflector shapes. TracePro’s reflector and lens simulation utilities are specifically designed to help CAD designers without traditional optical engineering expertise design LED optical components quickly.
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Cree Sets New Efficiency Benchmark with First 200 lpw LED Luminaire Prototype
Cree, Inc. raises the performance bar again with the demonstration of the first 200 lumen-per-watt (LPW) LED concept luminaire, which is more than twice the efficiency of the best linear fluorescent luminaires. The latest Department of Energy (DoE) projections* had estimated that this level of luminaire efficiency would not occur until after 2020, but Cree’s latest innovation has made this possible six years sooner than projected. The prototype leverages Cree’s vertical integration with innovations in LED chips, optics, materials technology and novel system design to deliver unprecedented performance. Read more »
The Right Choice of Current-Limiting Resistors for Constant Voltage LED Drivers
While LEDs are mostly driven by current sources, there are also several applications where constant voltage drivers are used. In that case current limiting resistors are mandatory. But that raises the question which resistor is the right one to guarantee reliable and accurate control while not compromising efficiency. Phil Ebbert, VP of Engineering at Riedon Inc. explains what to take care of and how to determine the correct parameters.
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LED Lighting Masters the Art of In-Flight Calm on Airbus A380s and Boeing 787s
Aboard a state-of-the-art aircraft might be the last place you would think of yourself enjoying a warm “candlelit” dinner, followed by a good night’s sleep under a starry night sky. The truth is, the latest aircraft cabins seek to provide just that – a revolutionary in-flight experience through the use of mood lighting. Mood lighting uses the full spectrum of colors and the ability to change these colors continuously with LEDs to mimic or enhance a sunrise morning or a bright, fresh afternoon or a cool evening that winds down the day. These lighting effects even seek to reduce your likelihood of jetlag. LED lighting programs can be specifically designed to gradually shift your waking and sleeping biorhythms to match that of your destination city.
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The Connected Lighting Alliance Extends Scope to Indoor Professional Lighting
Following its endorsement of ZigBee Light Link as the preferred common open standard for residential connected lighting applications, The Connected Lighting Alliance announced today the launch of a new initiative focused on the indoor professional lighting market. The Alliance will analyze market requirements for indoor professional lighting applications and identify standard development organizations to engage with. As an open association, the Alliance invites interested companies to join the industry initiative and share their expertise in this field. The contribution of multiple companies in the lighting industry will greatly benefit the global adoption of wireless lighting solutions.
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The Connected Lighting Alliance Extends Scope to Indoor Professional Lighting
Following its endorsement of ZigBee Light Link as the preferred common open standard for residential connected lighting applications, The Connected Lighting Alliance announced today the launch of a new initiative focused on the indoor professional lighting market. The Alliance will analyze market requirements for indoor professional lighting applications and identify standard development organizations to engage with. As an open association, the Alliance invites interested companies to join the industry initiative and share their expertise in this field. The contribution of multiple companies in the lighting industry will greatly benefit the global adoption of wireless lighting solutions.
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Zhaga Publishes Book 7 and Book 8 Interface Specifications for LED Light Engines
Two more interface specifications for LED light engines have been published by the Zhaga Consortium. Zhaga is an international organization that is enabling the interchangeability of LED light sources made by different manufacturers. The interface specifications, designated Book 7 and Book 8, can now be downloaded from the Zhaga website .
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Zhaga Publishes Book 7 and Book 8 Interface Specifications for LED Light Engines
Two more interface specifications for LED light engines have been published by the Zhaga Consortium. Zhaga is an international organization that is enabling the interchangeability of LED light sources made by different manufacturers. The interface specifications, designated Book 7 and Book 8, can now be downloaded from the Zhaga website .
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UC Santa Barbara: Optimizing Phosphors Using Simple Guidelines Improves Efficiency of Solid-State Lighting
By determining simple guidelines, researchers at UC Santa Barbara's Solid State Lighting & Energy Center (SSLEC) have made it possible to optimize phosphors –– a key component in white LED lighting –– allowing for brighter, more efficient lights.
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DOE Publishes Report on Color Stability of LED Lighting Products
The U.S. Department of Energy (DOE) has published a new report, Color Maintenance of LEDs in Laboratory and Field Applications. Although concern for parametric failure of LED lighting products has largely been focused on lumen maintenance, color shift is a cause of early failure for some products, especially in applications where visual appearance is critical.
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Los Alamos National Laboratory Announces Dramatic Improvements in QD Technology
Dramatic advances in the field of quantum dot light emitting diodes (QD-LEDs) could come from recent work by the Nanotechnology and Advanced Spectroscopy team at Los Alamos National Laboratory.
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Latest LRC Program Aims to Fine Tune Light for Greenhouse Crops & Medicinal Plants
Light and plants expert Tessa Pocock, Ph.D., recently joined the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute as a senior research scientist, leading the development of a new plant physiology lighting program. Her research focuses on plant photosynthesis, and plant development and regulation by light for traditional greenhouse crops and the emerging field of medicinal plants. Read more »
Two-Switch Flyback Solution for LED Street Lighting
LEDs provide high efficiency and long life compared to conventional lighting sources. Therefore, they are becoming first priority of lamp types to reduce energy consumption for internal or external lighting. This is also the case in street lightings where better efficiency and longer life are essential for less cost. A switching power supply designed to power up LED lamp should also have high efficiency and robustness to assure maintenance free lifetime as long as LED lamp. Resonant converters are one of the most popular power supply topologies here since their performance delivers increased power efficiency. LLC resonant converter has drawn attention thanks to its features such as high power conversion efficiency and low voltage stress on secondary rectifier. However, complicated design and high manufacturing cost of LLC resonant converters have been obstacles to fast time-to-market and cost reduction. Another problem of LLC resonant converter is large circulating current that is required to maintain zero voltage switching (ZVS). It causes relatively high power consumption at light load. LLC resonant converter also has potential failure issue when MOSFET with poor body diode performance is used. Two-switch flyback converter is proposed as an alternative solution to overcome the limitations of the LLC resonant converter. With additional switch on the high side, leakage inductance energy is clamped and recycled back to input to improve efficiency. The dissipative snubber circuit is no longer needed. A 120W rated switching power supply is designed utilizing two-switch flyback topology. The details of design specification and test results are presented.
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Why Pin Fin LED Coolers Perform Better Under Tilted Position?
For the experiment we compare the ModuLED 9980 with the LPF11180-ZHE. The ModuLED 9980 is a passive LED cooler from extruded aluminium with a diameter. of 99mm and a height of 80 millimeter, thermal resistance under vertical position 1.02°C/W. The LPF11180-ZHE is a passive LED cooler with pin fin structure with a diameter of 111mm and a height of 80mm, thermal resistance under vertical position 1.07°C/W.
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New Comprehensive Investigation on LED Phosphors and Down-Converters Patents
Yole Développement announces its new market & technology patent investigation, LED Phosphors and Down-Converters. Hundreds of companies are involved in LED phosphor IP. Most of the major LED players are present in the list of the top patent assignees. But independent phosphor manufacturers are also emerging as major forces in the IP landscape.
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