LED professional Review (LpR) - Articles

LpR Article | Innovation | Dec 15, 2016

On-Chip Beam Forming Optics Paves the Way for New Luminaire Designs

On-Chip Beam Forming Optics Paves the Way for New Luminaire Designs An LED luminaire’s optical system usually consists of primary and secondary optics. This concept always causes a trade-off between light quality, system size, efficiency and light distribution. New concepts to make secondary optics obsolete have already been researched. Paul Drosihn, Head of Modular Products, and Samir Mezouari, Optics & Lighting Design Specialist at Plessey Semiconductors present the first of its kind chip scale beam forming technology, StellarTM. They explain how it works and how it helps to overcome the limitations of traditional optical solutions for LED lighting. Read more »

LpR Article | Technologies | Nov 02, 2016

Optical Lithography Method for Advanced Light Extraction in LEDs

Optical Lithography Method for Advanced Light Extraction in LEDs Objective material selection for various target applications is key for successful product development. Efficient light extraction features are crucial for highly efficient LEDs. Thomas Uhrmann and Harun Solak, et.al* from EV Group and Eulitha AG will demonstrate a novel lithography method, PHABLE™, that enables the printing of sub-μm patterns in a non-contact, proximity process. Read more »

LpR Article | Oct 26, 2016

Handheld Photometry Supports LED Lighting Design

Handheld Photometry Supports LED Lighting Design With SSL new dimensions were introduced to light measurement, especially concerning handheld light measurement tools. Norbert Harkam, General Manager at SalesLink GmbH, a Representative of UPRtek, explains what criteria have to be considered and what the requirements of a handheld photometer are. Read more »

LpR Article | Oct 24, 2016

LEDs Reveal Paintings Hidden in Paintings

LEDs Reveal Paintings Hidden in Paintings Artists are often early adopters of new technologies and new solutions and methods that bring art to a new level. For fine arts artist, light and their material are the two major elements to play with. It’s no wonder that LED lighting has become an important element for them. The artist, Clint Eccher, and Arno Grabher-Meyer from LED professional show how LED lighting is used to transform static paintings into some of the most advanced paintings in the world, in dynamic, “living” pieces that transform their appearance with LED light. Clint Eccher's work, how it is done, and the role of LED technology will be explained. Read more »

Health + Environment | LpR Article | Oct 20, 2016

Botanical Light Pollution - Red is the New Blue

Botanical Light Pollution - Red is the New Blue In the beginning, the industry argued that LED lighting could help reduce light pollution. Meanwhile, various organizations claim the opposite effect is true and often sight light color as an issue. The opinions of different groups are frequently quite the contrary to those of other groups. Ian Ashdown, FIES Chief Scientist at byHeart Consultants & Lighting Analysts, demonstrates and discusses the negative effects of light pollution through LED lights and how different light sources affect vegetation. Read more »

LpR Article | Oct 17, 2016

How to Design with LEDs: Concurrent Engineering Yields Fully Optimized Lighting Systems

How to Design with LEDs: Concurrent Engineering Yields Fully Optimized Lighting Systems LEDs are often viewed as a replacement for other light sources. The right starting point for designing an appropriate replacement is crucial to the result. Brian S. Jasenak, Optical and Process Engineer at Kopp Glass, describes a concurrent engineering approach that optimizes the optics and other system components, and may help to reduce the number of LEDs needed as well as the overall cost of the LED lighting fixture. Read more »

LpR Article | Technologies | Oct 17, 2016

High-Index Nanocrystals - Key to Next Generation Advancements in Lighting

High-Index Nanocrystals - Key to Next Generation Advancements in Lighting Solid-State Lighting is destined to be a next generation lighting option. LEDs have already entered main stream applications and OLED technology has advanced greatly in the past few years in terms of efficacy and performance. Both technologies need to continue to improve performance to achieve high market acceptance. Dr. Gregory Cooper, Chief Technology Officer and Founder of Pixelligent Technologies LLC, illustrates how LED and OLED technology can advance to the next level by incorporating nanomaterials into existing packaging. Read more »

LpR Article | Oct 13, 2016

Easing Lighting System Design with Online Tools

Easing Lighting System Design with Online Tools The technical intricacies of an LED lighting system design can be quite complicated. The interdependencies of design parameters such as light source flux, efficacy, lumen maintenance, drive current, series/parallel light source layout, compatible optics, compatible drivers, thermal dissipation and others make the calculation of system performance a laborious process if performed manually. One simple change in one parameter could potentially force the lighting designer to consult the datasheet for every other component considered in the design in order to calculate the impact on the system as a whole. Patrick Durand, Worldwide Technical Director, Future Lighting Solutions demonstrates the capabilities of modern online tools to solve these problems giving a typical application example based on the Future Lighting System Creator (LSC). Read more »

LpR Article | Technologies | Oct 10, 2016

Technologies for Engineering an LED Light Closest to Sunlight

Technologies for Engineering an LED Light Closest to Sunlight TRI-R is a next-generation LED light source made possible by Toshiba Materials technology and commercialization together with TOL STUDIO. Using natural light that recreates the solar spectrum, TRI-R suppresses glare, prevents the loss of object color, and gives fresher, clearer expression to textures and details. Based on professional research examining the relationship light has with humans and the environment, this is illumination technology that provides the world surrounding us with the true and real value of light. Masahiko Yamakawa, Senior Specialist of Toshiba Materials Co.LTD., presents how this technology was developed and applied in some projects. Read more »

LpR Article | Oct 07, 2016

Lighting Fabrics - A New Approach for Flexible Light Sources

Lighting Fabrics - A New Approach for Flexible Light Sources Different groups from the lighting business have been dreaming of truly flexible light sources for a long time. OLEDs are being promoted as the solution of the future but there are other solutions already on the market. Managing Director R&D at Carpetlight GmbH, Mr. Till Sadlowski, takes a look at the common history of light and fabrics, the evolution of flexible circuity and the latest development in form free scalable light sources. Read more »

LpR Article | Technologies | Oct 07, 2016

MOCVD Platform for Cost-Effective Production of GaN-based HB LEDs

MOCVD Platform for Cost-Effective Production of GaN-based HB LEDs GaN-based blue and ultraviolet light emitting diodes (LEDs) are steadily becoming more widely used in solid-state lighting (SSL) applications [1-3]. Enabling dramatic energy savings when compared to contemporary incandescent bulbs and fluorescent lamps, these high-brightness LEDs (HB-LEDs) have a market potential in the billions of dollars. Yole Development estimates that by 2017, the market for LEDs will be approximately $75 billion [4, 5]. Shiping Guo, the Senior Technology Director of Advanced Micro-Fabrication Equipment Inc. presents a new approach to support this goal with a cost effective MOCVD solution for HB-GaN LED manufacturing. Read more »

LpR Article | Technologies | Sep 30, 2016

OLED Technology in Lighting Applications

OLED Technology in Lighting Applications Prototypes and niche applications with OLEDs for lighting have been demonstrated over the past few years. Now there are indications that OLED technology is ready for mass production or at least will be ready very soon. Franco Musiari, Technology Specialist at ASSODEL analyzed the current status and future perspectives of OLED technology. Read more »

LpR Article | Sep 23, 2016

Natural Design for Heat Sinks

Natural Design for Heat Sinks The luminous flux of LEDs decreases with the rise of the operating temperature. Therefore the dissipation of the heat is, aside from the efficiency of the LED chip itself, an essential part in the development of efficient LED systems. Christian Herbold and Cornelius Neumann from the Light Technology Institute at the Karlsruhe Institute of Technology analyzed natural inspired shapes and show an approach to heat sinks that combine high thermal performance with a high aesthetic value. Read more »

LpR Article | Technologies | Sep 12, 2016

LED and Lens Degradation Through Volatile Organic Compounds

LED and Lens Degradation Through Volatile Organic Compounds In general, LEDs are very resistant light sources. Nevertheless, glues, conformal coatings, o-rings, gaskets, and potting compounds, all materials that are frequently used in the construction of LED based luminaires or lamps and often contain volatile organic compounds (VOCs) may have a negative impact on performance, reliability and lifetime. Edward Steinke, application engineer at Cree, explains the set of problems and how to prevent these issues based on Cree’s products, using their test kit components, as well as components for lamp and luminaire applications. Read more »

LpR Article | Sep 01, 2016

Discomfort Glare Perception of Non-Uniform Light Sources in an Office Setting

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. Read more »

LpR Article | Research | Aug 29, 2016

Quality and Health Aspects of LED Lamps for the European Residential Lighting Market

Quality and Health Aspects of LED Lamps for the European Residential Lighting Market Because of shortfalls in regards to consumer information about high quality, energy efficient, substitute products for incandescent lamps, there has been a significant amount of irritation on the side of the consumer. As part of the Intelligent Energy Europe Program of the European Union, Prof. Dr. Georges Zissis from the Paul Sabatier - University Toulouse and his team investigated 370 LED lamps. All relevant parameters of 95 different lamp types from store shelves in 12 European countries were measured and evaluated regarding quality and health issues. Read more »

LpR Article | Aug 25, 2016

LED Lamps Recycling Technology for a Circular Economy

LED Lamps Recycling Technology for a Circular Economy While having a long propagated lifetime, LED lighting products, especially lamps, have a foreseeable end of life. And since they contain many valuable elements they practically beg to be recycled. However, like other highly integrated electronics products recycling is not a simple task. Andrea Gassmann, Jörg Zimmermann, Roland Gauß, Rudolf Stauber and Oliver Gutfleisch from the Fraunhofer Project Group Materials Recycling and Resource Strategies IWKS and the Technische Universität Darmstadt Institute for Materials Science respectively, present and discuss a method that could open the way to successful recirculation of precious components and materials. Read more »

LpR Article | Technologies | Medical | Aug 22, 2016

High-End White Light Sources Fiber Optics Technology for Medical Applications

High-End White Light Sources Fiber Optics Technology for Medical Applications Often technologies that are too expensive for the mass market at the beginning are already adopted in medical applications. When reaching a certain level of maturity, costs usually become more reasonable and adaptations for the consumer market begins. Holger Laabs, Oliver Mehl and Henning Rehn from Osram GmbH present a light source technology and its prerequisites for fiber optics that could become one of these technologies. Read more »

LpR Article | Aug 19, 2016

Status of Micro- and Nanostructured 3D LED Technologies

Status of Micro- and Nanostructured 3D LED Technologies Conventional LEDs are planar, two-dimensional (2D) devices that emit light from a thin material layer at or near their flat surface. The vast majority of LEDs are made of GaN and InGaN material requiring expensive substrate wafers made of sapphire, silicon carbide or gallium nitride. The 3D WireLED technology uses silicon wafers for wafer diameters of 8 inches or larger. On each wafer, millions of vertical microwires and microrods of GaN are grown, each with a diameter of less than one micron. Mr. Arno Grabher-Meyer and Mr. Siegfried Luger from LED professional, talked with the General Manager of Aledia, Mr. Giorgio Anania about the status of this innovative technology. Read more »

LpR Article | Quality | Aug 17, 2016

TM-30 or the Quest for New Metrics to Measure Light Color Quality

TM-30 or the Quest for New Metrics to Measure Light Color Quality As the lighting industry’s need for an unambiguous measure of lighting color quality becomes more urgent, the TM-30 test method put forward by the Illumination Engineering Society of America (IES) is one approach that could offer a solution. Arno Grabher-Meyer, Editor in Chief at LED professional gives a quick status overview. Read more »

LpR Article | Technologies | Aug 15, 2016

Concepts to Overcome Lifetime Issues of LED Drivers

Concepts to Overcome Lifetime Issues of LED Drivers Lighting technology has changed significantly in recent years after a century of little to modest advancements. LED luminaires offer advancement in lower power consumption and expected life. Maggie Nadjmi, EE Product Manager at SL Power Electronics, explains why this new technology will probably not meet the life and reliability expectations if no attention is paid to the drivers and power supplies used to power LEDs. She discusses the main components affecting lifetime and how to eliminate them or design a product to still achieve the desired lifetime. Read more »

LpR Article | Research | Aug 11, 2016

Flicker Beyond Perception Limits - A Summary of Lesser Known Research Results

Flicker Beyond Perception Limits - A Summary of Lesser Known Research Results Since the introduction of fluorescent lamps, the lighting industry knows about flicker issues. However, many aspects are still unclear. Especially effects beyond the flicker fusion threshold are mostly ignored, and sometimes even denied. Dr. Walter Werner, CEO of Werner Consulting, gives a summary of research results indicating that further research is needed and that for high quality lighting very likely a much higher PWM modulation frequency is required. Read more »

LpR Article | Aug 08, 2016

Form Factor Luminaires and Light Effects

Form Factor Luminaires and Light Effects If luminaires designed for traditional light sources are simply retrofitted with LED light sources like it occurs in the so-called “1st wave of LEDification”, they will always fall short of expectations in many points. Herbert Weiß and Thomas Noll from Osram GmbH, Martin Möck from the University of Erlangen-Nuremberg, Martin Creusen from Philips Lighting, and Friedhelm Holtz from Insta Elektro GmbH explain why these shortcomings were addressed and which solutions were developed in the EnLight project. Read more »

LpR Article | Technologies | Aug 05, 2016

Reliability Oriented Design of LED-Based Light Sources

Reliability Oriented Design of LED-Based Light Sources The transition from traditional light sources to SSL systems requires a different design philosophy to achieve the advantages offered by LED light sources. The key approach is based on the parallel design of thermal, electrical, optical and spectral properties of the light source. Matteo Meneghini, Gaudenzio Meneghesso, Enrico Zanoni and Matteo Dal Lago from the Department of Information Engineering at the University of Padova, and Nicola Trivellin from LightCube SRL explain this approach including the importance of the electrical management of LEDs, comparing modulation techniques to constant current, differentiating between versatility and efficiency. Read more »

LpR Article | Aug 01, 2016

DMI Specification Defines Electrical Interface between LED Drivers and Modules

DMI Specification Defines Electrical Interface between LED Drivers and Modules Enabling LED modules and LED drivers to be fully interchangeable at the component level requires a specification for the electrical interface between the driver and module (DMI). Arnulf Rupp of Osram GmbH, a member of both the Zhaga Consortium and MD-SIG, explains the role of both organizations in developing and implementing a consistent, easy to use, cross-vendor DMI specification. Read more »

LpR Article | Jul 29, 2016

Contactless LED Technology

Contactless LED Technology While Contactless power distribution using electromagnetic induction technology is not new, it is rarely used in an LED illumination system. Alain Guimont, an IES member and Product Specialist at HEICO lighting™, one of the few companies that designs products based on this type of an approach, explains how it works and discusses the advantages of this technology. Read more »

LpR Article | Technologies | Jul 28, 2016

InGaN Nanowires Make Light Mixing Efficient and Smart

InGaN Nanowires Make Light Mixing Efficient and Smart The correlated color temperature (CCT) of high color rendering index (CRI) LED lighting systems can, in principle, be tuned over a wide range. As an alternative approach to conventional phosphor based LEDs, a full-color LED array consisting of red, green and blue (RGB) InGaN based nanowire LEDs monolithically integrated on a micro-scale level has been proposed and fabricated. J. Lee from the Nano Electronics Lab at the Samsung Advanced Institute of Technology, Renjie Wang, Hieu P. T. Nguyen, Ashfiqua T. Connie, Ishiang Shih, and Zetian Mi from the Department of Electrical and Computer Engineering at McGill University in Montreal explain how this technology works and how the three multi-color subpixels on the same chip can be separately biased and can exhibit full-color emission which can be tuned controllably in a wide CCT range. Read more »

LpR Article | Jul 25, 2016

More Efficient Plant Growth with Quantum Dots by Nanoco Lighting

More Efficient Plant Growth with Quantum Dots by Nanoco Lighting Using LEDs for plant growth lights is nothing new, nor is the use of QDs in LED lighting. While it is already proven that LED systems have big advantages over conventional plant lighting technologies, it is not common knowledge that Cd-free QDs are ideal candidates for optimizing the light spectrum for plant growth systems. Dale Needham, Business Development Director-Lighting at Nanoco Lighting, explains the opportunities and advantages based on Nanoco’s proprietary and patentprotected CFQD® cadmium-free quantum dot LED grow lighting systems. Read more »

LpR Article | Jul 25, 2016

Zhaga Evolves: Focus on Component Standardization Drives New Book Development

Zhaga Evolves: Focus on Component Standardization Drives New Book Development With new specifications covering COB LED arrays, LED drivers, and other LED modules and light engines, Zhaga is making rapid progress in standardizing these types of components in response to the needs of the market. Musa Unmehopa, Secretary General of the Zhaga Consortium, and Tim Whitaker, Director of Marketing Communications of the Zhaga Consortium, describe how Zhaga is evolving and changing its focus in a number of areas. Read more »

LpR Article | Research | Jul 21, 2016

A Graphene-Based, Spectrally Tunable, Flexible Field-Effect Light-Emitting Device by the Tsinghua University and the Tsinghua National Laboratory for Information Science and Technology

A Graphene-Based, Spectrally Tunable, Flexible Field-Effect Light-Emitting Device by the Tsinghua University and the Tsinghua National Laboratory for Information Science and Technology The continuous tuning of the emission spectrum of a single light-emitting diode (LED) by an external electrical bias is of great technological significance as a crucial property in high-quality displays and may be used in high quality lighting applications, yet this capability has not been demonstrated in existing LEDs. Graphene, a tunable optical platform, is a promising medium to achieve this goal. Xiaomu Wang, He Tian, Mohammad Ali Mohammad, Cheng Li, Can Wu, Yi Yang, and Tian-Ling Ren from the Institute of Microelectronics at the Tsinghua University in Beijing and the Tsinghua National Laboratory for Information Science and Technology (TNList) demonstrate a bright spectrally tunable electroluminescence from blue (~450 nm) to red (~750 nm) at the graphene oxide/reduced-graphene oxide interface. Read more »

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