Trends
Trends
Technologies | LpR Article
A New Approach to the Design of Driverless AC LED Light Engines
Driverless AC LED light engines have now become a commonplace item of commerce in the lighting industry. Nearly all of them use high voltage integrated circuit switching chips to intelligently change the number of LEDs in a string during a power line cycle so that the voltage of the LED string matches the instantaneous power line voltage. However, customers are demanding higher efficiency, lower cost, and especially a reduction in the flicker content of the emitted light. Peter W. Shackle, president of the consulting company, Photalume, describes some new circuits for AC LED light engines [1] that provide a non-dimming solution with reduced cost, increased efficiency and better light quality as perceived by the human eye.
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Research | LpR Article
LED Office Lighting for Improved Well-Being and Performance
The influence of artificial light in industry has been a topic of conversation for a while now but opportunities provided by LED lighting have made this subject even more important. Katrin Möller, Junior Researcher at the Competence Center Light, her research partners, Vincent Grote from the Human Research Institut, and Birthe Tralau from Zumtobel Lighting, investigated the effects of LED and fluorescent lamp lighting on human well-being and performance in an office environment, in a comparative laboratory study.
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Research | LpR Article
Direct Current (DC) Supply Grids for LED Lighting
Since many alternative energy sources as well as electronics and controls technologies are based on DC current, DC grids have been investigated more intensely in the last decade. DC grids with a centralized AC/DC conversion have proven to be advantageous in server farms. While LED lighting is also a DC current related technology, an obvious choice would be to use DC grids for them. Prof. Eberhard Waffenschmidt from the Cologne University of Applied Science in conjunction with Philips Research presents the results of an office building DC lamp system installation with photovoltaic (PV) support.
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Research | LpR Article
A Self-Compensation Approach for Maintaining the Chromaticity Coordinates of Phosphor Converted LEDs Upon Temperature Variations
Solid-state light sources for general illumination applications are currently becoming more and more popular. Maintaining chromaticity coordinates over temperature is a challenge. Wolfgang Nemitz, Franz P. Wenzl, Susanne Schweitzer, Christian Sommer, Paul Hartmann from the Institute for Surface Technologies and Photonics at Joanneum Research, and Paul Fulmek and Johann Nicolics from the Institute of Sensor & Actuator Systems of the Vienna University of Technology investigated this issue and propose a promising new solution.
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Resources | Reports | Technologies | Controls
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Jul 22, 2015
NLPIP Releases Report on Wired and Wireless Lighting Controls
The National Lighting Product Information Program (NLPIP) at Rensselaer Polytechnic Institute’s Lighting Research Center (LRC) recently released its latest publication, Lighting Answers: Comparison of Wired and Wireless Lighting Controls for Single Rooms.
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White Paper | Technology
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Jul 21, 2015
Litecool Demonstrates that Narrow Beam LED Packages Are a Real Possibility
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.
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Technologies | Thermal Management
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Jun 24, 2015
Litecool Turns LED Packaging on Its Side
Litecool has produced LED packages in a vertical orientation rather than horizontal. This means that the dielectric layers only have a minor impact on the thermal performance of the LED package and allow the heat to escape more effectively through the metallic parts of the package. This has significant benefits for flip-chip packaging where dielectric layers are usually very close to the diode.
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Resources | Roadmap | DoE | Technologies | SSL
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Jun 15, 2015
DoE: Solid-State Lighting R&D Plan
The solid-state lighting (SSL) revolution signals a profound shift in how we will use and consider lighting and represents a huge opportunity to generate significant energy savings. The energy being used for lighting represents a significant portion of global energy use. Rising electricity prices, mounting concerns about climate change, and desire for energy independence are causing the global lighting market to shift toward more energy-efficient light sources.
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White Paper | Technology
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May 27, 2015
BluGlass Demonstrates Improved Performance Results for Green RPCVD Manufactured p-GaN LEDs
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.
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Technologies | Electronics
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May 27, 2015
Power Conversion Efficiency - Key for Stand-Alone Solar Powered Lighting in Nordic Regions
Stand-alone solar powered lighting solutions are made possible even in the Nordic region through a new, ground-breaking Danish project. An ideal collaboration between scientists from 4 different fields and private companies has succeeded in creating a system and a methodology that makes the impossible possible: Outdoor solar lighting which is not just a decoration.
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Technologies | Optics | Material Science
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May 12, 2015
ORNL Superhydrophobic Glass Coating Offers Clear Benefits - Maybe Also for Lighting Optics
A moth’s eye and lotus leaf were the inspirations for an antireflective water-repelling, or superhydrophobic, glass coating that holds significant potential for solar panels, lenses, detectors, windows, weapons systems and many other products. The discovery by researchers at the Department of Energy’s Oak Ridge National Laboratory, detailed in a paper published in the Journal of Materials Chemistry C, is based on a mechanically robust nanostructured layer of porous glass film. The coating can be customized to be superhydrophobic, fog-resistant and antireflective.
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Technology
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May 04, 2015
Configuration Via the Mains: Simple, Reliable and Professional
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.
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White Paper | Technology
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Mar 30, 2015
TRIAC Dimmable, Isolated LED Driver with High Power Factor Needs No Opto-Isolators
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.
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White Paper | Technology
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Feb 17, 2015
The Future of More Efficient LEDs and Lasers Probably Starts in 2D
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.
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White Paper | Technology
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Feb 16, 2015
Osram Improves Efficiency of Blue LED Chips by Reducing Forward Voltage
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.
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White Paper | Technology
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Feb 05, 2015
Universities Develop Novel LEDs by Band-Structure Engineering in van der Waals Heterostructures
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.
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White Paper | Technology
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Jan 15, 2015
Ending the Invisible Threat - Confronting the LED Flickering Issue
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.
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White Paper | Technology
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Jan 09, 2015
Compute Simulation Sheds Light On Why Blue LEDs Are So Tricky To Make
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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White Paper | Technology
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Jan 09, 2015
LpS 2014 Scientific Award Winner Article: New Binning Strategy for White LEDs
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.
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Resources | Reports | Market | Technologies | OLEDs
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Dec 11, 2014
Research and Markets Announces OLED Lighting Opportunities 2015-2025 Forecast
OLED lighting is an emerging solid-state lighting technology. It potentially provides a route into the large and growing global lighting market. The lighting market is however complex as it is a highly fragmented space thanks to the existence of a broad technology mix and a diversity of customer needs.
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White Paper | Technology
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Nov 21, 2014
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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Technology
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Nov 06, 2014
Osram Reports Record Figures for Green InGaN-Based and Conversion LEDs
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 addition, another green LED developed by combining a blue chip with a phosphor converter has achieved a record-breaking efficacy exceeding 200 lm/W.
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Technology
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Oct 07, 2014
And the Nobel Price 2014 Goes To ... The Inventors of the Blue LED
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.
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Technology
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Sep 25, 2014
Nanotechnology May Lead to Better, Cheaper LEDs
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 method should yield similar improvements in LEDs made in inorganic (silicon-based) materials used most commonly today.
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Technology
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Sep 18, 2014
LpR 44 Article: Discomfort Glare Perception of Non-Uniform Light Sources in an Office Setting
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.
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White Paper | Technology
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Aug 28, 2014
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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Technologies | Optics | Material Science
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Jul 04, 2014
Novel Nanoparticle Production Method Could Lead to Better LED Lights, Lenses and Solar Cells
Sandia National Laboratories has come up with an inexpensive way to synthesize titanium-dioxide nanoparticles and is seeking partners who can demonstrate the process at industrial scale for everything from solar cells to LEDs. Titanium-dioxide (TiO2) nanoparticles show great promise as fillers to tune the refractive index of anti-reflective coatings on signs and optical encapsulants for LEDs, solar cells and other optical devices.
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Technology
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Jul 03, 2014
Significant Technical Progress - BluGlass Demonstrates Best Ever RPCVD (p-GaN) Light Output
Australian Cleantech innovator, BluGlass Limited, has announced today that it has been successful in demonstrating the best ever p-GaN light output using its propriety technology, Remote Plasma Chemical Vapour Deposition (RPCVD) on an MOCVD partial LED structure. This result is greater than a 10 fold improvement in LED efficiency over the first p-GaN demonstration data published by the company in December 2012, when the same measuring methodology is applied. This has been achieved by making significant improvements in addressing the ‘interface challenge’, a key technical hurdle that has been limiting the p-GaN performance demonstration in the past.
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Technologies | Measurement
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Jun 18, 2014
How Much Can the Color of Nominal CCT Vary?
The threshold at which a color difference becomes perceptible is defined by a MacAdam ellipse. A MacAdam ellipse is drawn over the color space in such a way that the color at its center point deviates by a certain amount from colors at any point along its edge. The scale of a MacAdam ellipse is determined by the standard deviation of color matching (SDCM). A color difference of 1 SDCM “step” is not visible; 2 to 4 steps is barely visible; and 5 or more steps is readily noticeable.
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Technology
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Apr 14, 2014
Developing Phosphor-Free White Light from Nanopyramid LEDs
Researchers in China have used nitride semiconductor nanopyramid structures to create light-emitting diodes (LEDs) with spectra that are similar to those provided by ‘white light’ LEDs with yellow phosphors [Kui Wu et al, J. Appl. Phys., vol115, p123101, 2014]. The researchers are at the Chinese Academy of Sciences’s institutes of Semiconductors and Mechanics, and Tsinghua University. A similar CAS/Tsinghua team previously reported such devices, using a polystyrene nanosphere mask to make holes for selective-area growth of nanopyramids.
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