Articles & Interviews

LpR Article | Jun 20, 2016

Advanced Optical Plastics Materials for LED Lighting Applications by Styron LLC

Across a range of lighting solutions, Light Emitting Diodes have emerged as the clear choice for industry and consumers alike. Government regulations and consumer preference for more environmentally-conscious, energy-efficient products have caused manufacturers to develop solutions for the marketplace that offer new levels of energy efficiency, durability and long life. While the technology has evolved, so have the materials that go into the finished product. Claude Van Nuffel, Eric Wu, Peter Jackson and Marta Sans Peña from Styron LLC discuss versatility and one-of-a-kind properties of plastic – especially polycarbonate and polycarbonate blends – and why they have become the “materials of choice”. Read more »

LpR Article | Jun 20, 2016

Advanced Passive Thermal Management Solutions for High Power LEDs by Advanced Cooling Technologies (ACT)

There are two main solutions to improve passive thermal management in LED devices. One is to increase the surface area of a heat sink. This requires additional size, weight and material and offers only marginal improvement. The second solution is to increase the thermal conductivity between the heat source and the sink. The latter is supported by well-established technologies like heat pipes and vapor chambers. Richard Bonner, Manager for Custom Products, and Peter Ritt, Vice President at Advanced Cooling Technologies (ACT) give insight into the latest developments and explain how they work, how they are designed and applied correctly, and discuss their opportunities, advantages and limitations. Read more »

Resources | LpR Article | Special Applications | Artificial Intelligence | Dec 16, 2019

AI & Lighting

LpR 73 Article, page 62: Recently, Artificial Intelligence has emerged as an evolutionary force in almost every industry, demonstrating its potential to radically change existing processes. In common literature, AI is interchangeably used with Machine Learning for which various tools have already become commonplace. Henri Juslén, D.Sc (tech.), Chief Future Illuminator, Omar Nasir, M.Sc (tech.), Data Scientist, and Javad Nouri, M.Sc, Data Scientist at Helvar Oy Ab discuss AI on the context of the lighting industry where the scope of applications of AI is similarly quite broad, impacting the various stages involved in the lighting life-cycle such as design, installation, commissioning and configuration. Read more »

LpR Article | Research | Jun 07, 2016

Al2O3 Coated Europium- Activated Aluminum Silicon Nitride for COB LED Technology by the Graz University of Technology and Tridonic Jennersdorf

Eu2+ activated nitride phosphors have drawn much interest for solid state lighting because of their interesting photoluminescence. While they show excellent optical properties, they are hygroscopic and have the potential of being degraded by atmospheric moisture and high temperatures. A coating layer on the surface is an effective method to improve stability against moisture and oxidation. For use in chip on board technology, Nika Mahne, master student at the Institute of Inorganic Chemistry, A. Reichmann, B. Bitschnau, R. Fischer, from the Graz University of Technology, and F. Schrank from Tridonic Jennersdorf propose an approach where a CaAlSiN3:Eu2+ [1, 2, 3] phosphor was coated with Al2O3, obtained via a Brønsted precipitation reaction based on a solution-coating process from a mixture of aluminum halide with a base after annealing at a temperature of 400°C. Read more »

LpR Article | Jul 01, 2016

An Economical Omnidirectional A19 LED Light Bulb by the Industrial Technology Research Institute

Since 2009, when the Japanese government was vigorously promoting LED bulbs in end-market applications, they have become mainstream commodities in the LED lighting market. Chen-Peng Hsu, project manager of Electronics and Optoelectronics Research Laboratories at Industrial Technology Research Institute (ITRI), introduces the R&D 100 award-winning invention of an omnidirectional A19 LED light bulb that is light weight and economical. Read more »

Resources | LpR Article | Research | Light Generation | Oct 31, 2017

Hybrid Quantum Dot Light Emitting Electrochemical Cells

Several new light generation technologies that are overshadowed by LEDs and OLEDs are investigated. Most of these technologies are in a very early stage of research. One such technology, the LEC technology, was presented at LpS 2017. Light emitting electrochemical cells can be compared to OLEDs, but they are based on a much simpler inorganic architecture. The innovation in the presented approach lies in the combination with quantum dots, resulting in a hybrid solution. This novel attempt with all its consequences and future prospects was the reason that the LpS Scientific Award jury voted to bestow the award on Dr. Ekaterina Nannen, Group Leader of the Research Group „Solid State Lighting“ at the Nano-Energie-Technik- Zentrum (NETZ) of the University Duisburg-Essen and her research team, Julia Frohleiks and Svenja Wepfer. Read more »

Implications for Human-Centric Lighting Design in Tropical Nursing Homes: A Pilot Study

Light synchronizes our physiological and psychological rhythms to the 24-hour rhythm of the ambient changes. For the elderly, adequate environments to compensate for increasing frailty and sensory loss are crucial. Dr. Szu-Cheng Chien, Assistant Professor at the Singapore Institute of Technology reports from a pilot study that aimed to explore HCL design strategies in nursing homes in Singapore. Pre-/post implementation user surveys and quantitative evaluations were conducted. Read more »

LpR Article | Technologies | Jun 08, 2016

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 »

Research Reports | Smart Lighting + IoT | Resources | LpR Article | Oct 12, 2018

Integrating Lighting in the Internet of Things

LpR 67 Article, page 80: Following the rapid penetration of LEDs, lighting now becomes integrated into the Internet of Things. Over the past three years a consortium of leading European companies worked on the OpenAIS project, partly funded by the EU within the Horizon 2020 program. Now showing the results, the consortium is working on a full size demonstrator. Ben Pronk, System Architect at Philips Lighting Research, and Frank van Tuijl, Project Manager at Philips Lighting show how OpenAIS creates an open ecosystem to enable a wider community to deliver the smartness of light and they explain how it is possible to adapt the system to cater to the diversity of people and demands. Read more »

Interactive Lighting Control is Opening New Doors for LED Applications

LpR 69 Article, page 98: Advancements in lighting control technology are allowing for sophisticated interactivity in LED mapping. These new technologies are bridging the gap between lighting control and AI, with the ability to analyze and map data input (such as audio) in real-time. Installations driven by interactive LED control technologies have their place in a variety of application spaces. Manjinder Benning, Founder and CTO of Limbic Media, explains how this new technology works, what its applications are, and what the future of interactive lighting control looks like – not only for end-users, but also for lighting designers and technicians. Read more »

Interior Automotive Lighting Control Redefined

In modern car’s interior lighting, tough requirements and rising complexity are a huge challenge. A new industry consortium was formed to meet this technological challenge and to provide a comprehensive ecosystem for the new digital LED lighting paradigm. The founding members of the Open ISELED Alliance are Inova Semiconductors (ISELED "Digital LED" concept and LED controller), Dominant Opto Technologies (LED manufacturing and packaging), NXP (system microcontroller), TE Connectivity (system integration and connection technology) and Pforzheim University (theoretical framework). The alliance recently added LucieLabs (software, firmware), a French IoT Software startup to its line-up. The goal of all these organizations is to work in close cooperation to present a complete system solution - a true ecosystem. Roland Neumann, CTO of Inova Semiconductors introduces the challenges and the worked out innovative solution that uses a single system controller to individually address up to 4,096 LEDs. Read more »

Issue 63 | Challenges in UV Measurement

Over the past decade UV LEDs have emerged as a highly attractive alternative to conventional UV emission sources. They are cost effective and energy efficient devices in a small housing. These advantages allow new fields of applications and access to a larger group of users - even in the consumer market, e.g. water purification. Dr. Tobias Roesener, Product Manager at Instrument Systems, explains what makes accurate measurement of UV LEDs so complicated and what the crucial requirements on the measurement equipment are. In addition, he discusses calibration and stray light issues. Read more »

LpR Article | Jul 01, 2016

Labeling and Certification Testing Issues by UL

Arno Grabher-Meyer from LED professional summarizes several issues regarding certification and certification processes which were discussed with David Edwards, an expert in testing and compliance engineering for consumer products at UL. Read more »

Laser Technology for Lighting Applications: A Review and Analysis of a Promising Technology

LpR 68 Article, page 44: LEDs are currently the dominating light source: efficient and cost effective. But LEDs also have some drawbacks. Another interesting technology developed slowly in the shadow of LEDs and has become an interesting solution for some specific applications: GaN based blue solid state laser devices. Although this technology offers some very interesting advantages, it also has challenges. Nicola Trivellin, Matteo Buffolo, Carlo De Santi, Gaudenzio Meneghesso, Enrico Zanoni and Matteo Meneghini from the University of Padova and its spin-off LightCube have been working toward the development of experimental systems and demonstrators and disclose their findings of the comparison between LED and LD systems. Read more »

Lead Halide Perovskite Nanocrystals - A New Promise for Light Emitting Devices

Perovskites structured materials have attracted scientific and technological interest in the last four years. Recent studies have shown that these materials could deliver high photoluminescence efficiency at any desired wavelength in the visible spectrum. Mirko Prato and Francesco Di Stasio, Technologist and Marie Curie Fellow of the Institute of Photonic Sciences at the Istituto Italiano di Tecnologia focus on the application in single color LEDs (red, green and blue) and white emitting color-converting layers. They discuss what limits their application in everyday technology like toxicity and limited functional stability. Read more »

LpR Article | Technologies | Jun 28, 2016

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 »

LED Driver for High Power Machine Vision Flash

Automation is nothing new and its demands are rapidly increasing, either in production or inspection. More sensors are used and many are based on direct or reflected light detection. Some work in the visible range and others work in the non-visible spectrum of light. LED lighting has become the standard in most applications as the solid-state light source offers numerous advantages over other lighting technologies. However, the LED lighting system is only as good as the peripheral components and LED drivers are one key element in many applications. Keith Szolusha, LED driver applications manager and Kyle Lawrence, associate applications engineer, identified the challenges for machine vision flash applications and propose a solution example with Analog Devices' LT3932 high speed LED driver. Read more »

LED Driver Miniaturization - Opening New Opportunities for Solid State Lighting

While LEDs have significantly improved over the past decade, driver technologies have not kept pace and are, in some respects, the limiting factors for new applications. Size is a particular issue. Dramatically increasing the switching frequency helps to reduce size but often causes other issues or is costly. Mickey Madsen, CEO of Nordic Power Converters, explains how his company has overcome the hurdles and made it feasible by designing very high frequency LED drivers. Read more »

LpR Article | Aug 11, 2016

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 | Jun 20, 2016

LED Light Spectrum Enhancement with Transparent Pigmented Glazes

While LED bulbs have the distinct economic advantages of using less energy, producing less heat and lasting years longer than traditional incandescent bulbs, when objects are viewed under LED light, they frequently appear to be of different colors than when viewed in sunlight or with incandescent lights. Jan-Marie A Spanard from Light Spectrum Glazes proposes and explains an approach to optimize the spectral distribution of LED light to overcome this weakness. Read more »

LED Lighting Requires New Approaches in Optics

LpR 67 Article, page 88: Even though LED technology has been established LEDs still need new approaches in electronics, thermal management or optics to make complete use of their advantages. Marek Škereň, Chief Technology Officer of IQ Structures, explains how new optical devices, with the trade name Nanoptiqs, based on principles of diffraction are applied to achieve improved performance of white light illumination systems. This unique solution is based on full control over the modulation of material and geometric properties of the optical elements at a nano-level. A combination of complex transmission diffractive elements, with specially designed systems of micro-reflectors (produced using an innovative mass-production technique) is also presented as a promising flexible building unit for the construction of new generation luminaires. Read more »

Resources | LpR Article | Technologies | DC-Grids | Sep 17, 2019

LED Lighting Systems in Smart Buildings with DC Microgrids

LpR 72 Article, page 60: While electric motors for ventilation and air-conditioning systems were already DC-based in the past, powerful IT systems, LED lighting systems, photovoltaic systems with batteries and charging systems for electro mobility are now increasingly being used in modern building environments. They all need direct current (DC). Therefore, an obvious step is to equip modern buildings with DC grids. Carsten Moellers from Abalight discusses a number of unresolved questions and presents possible solutions in this article. Read more »

LpR Article | Jul 04, 2016

LED Market and Development Trends from the Point of View of a Full-Range Trader in Lighting by Everlight

In an interview with LED professional, Ms. Beate Jungwirth, Director of Marketing & Communications and PR at Everlight and Dr. Christopher Keusch, Senior Sales Manager at Everlight, talk about the market and development trends in the area of LEDs. The experts also discuss Everlight’s focus at the LED professional Symposium +Expo 2012 which takes place in Bregenz, Austria from September 25th to 27th. Read more »

LpR Article | Jul 04, 2016

LED Market and Development Trends from the Point of View of a Full-Range Trader in Lighting by Everlight

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. Read more »

LED-Retrofit Based on AlGaN/GaN-on-Si Field- Effect Transistor Drivers

Efficient driver technologies for LED systems are still a relevant topic. Several new approaches are proposed and new technologies are under development. Andreas Zibold, PhD student at the Fraunhofer Institute for Applied Solid State Physics IAF, and his co-authors, M. Kunzer, R. Reiner, B. Weiß, P. Waltereit, R. Quay, J. Wagner, and O. Ambacher demonstrate the suitability of AlGaN/GaNon- Si field effect transistors (FETs) for their use in LED drivers. The transistors are tested in an isolated buck converter and an efficiency of 86% is measured for the full converter circuit. The driver circuit is combined with an LED module based on a laser-structured Aluminum Nitride (AlN) ceramic board onto which 21 high power white-emitting LED chips are mounted. This combination resulted in an LEDRetrofit lamp with a total light output of 2676 lm at an efficacy level of 119 lm/W. The results compare favorably to state-of-the-art commercial solutions. Read more »

Trends | LpR Article

LEDs are Revolutionizing Light – The Past and Future of Lighting

Light is a basic part of life as such and modern living relies on artificial light. Lighting is a constantly developing, even accelerating technology, with LEDs representing the current zenith. On the occasion of the beginning of the IYL 2015, Stephan Wegstein representing VESTEL, a leading contract manufacturer in Turkey, has been asked to explain the challenges this poses and how suitable strategies and technologies can assist in staying on top of developments. Read more »

LpR Article | Sep 06, 2016

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 »

Lifetime- and Economic Efficiency Simulation of LED Luminaires in Dymola/Modelica

Article from LpR 66 | page 40: The lifetime of an LED system is usually specified by the LM-80 report using the TM-21 method. Unfortunately, this value is solely valid for one specific application. Sebastian Hämmerle and Thomas Schmitt from the University of Applied Sciences in Vorarlberg developed a new open-source Modelica library for dynamic simulation of LEDs: The DynaLed library. The aim of the work was to evaluate the lifetime and the corresponding economic efficiency of LEDs in dynamic operation by means of the LM-80 report and according to the TM-21 calculation method. Furthermore, it should be possible to use the library for component dimensioning, e.g. the heatsink. The primary task was to develop simulation models which can be parametrized with manufacturer information, e.g. the datasheet, but still provide sufficient accuracy. As an application example an LED louvre luminaire (Article Code: 29001077) from LEDON Lamp GmbH was simulated utilizing the developed library. At the end, results from the lifetime- and the economic efﬁciency simulation were discussed. Read more »

Resources | LpR Article | Special Topics | LiFi | Dec 16, 2019

LiFi as a Paradigm-Shifting 5G Technology

LpR 73 Articles, page 54: There are many misconceptions about LiFi, a wireless communication technology that uses the infrared and visible light spectrum for high speed data communication. Prof. Harald Haas, Professor of Mobile Communications at the Institute for Digital Communications from the University of Edinburgh, will explain what Light-Fidelity (LiFi) is and argue why it is a 5th Generation (5G) technology. Peak transmission speeds of 8 Gbps from a single light source have been demonstrated, and complete cellular networks based on LiFi have been created. Besides discussing numerous misconceptions, the potential impact this technology can have across a number of existing and emerging industries will be explained as well as new applications that LiFi can unlock in the future. Read more »