LED professional Review (LpR) - Articles

LpR Article | Commentary | Feb 21, 2018

Can You Show Me the Next S-Curve, Please?

Can You Show Me the Next S-Curve, Please? The evolution of technologies is often described using the “S-curve” model. In the early stage, in the first phase of its life cycle, technology is mainly driven by fundamental research. Only a few players are active at that time and innovation steps are quite large. In the second phase, early adopters start to develop products and bring them to market. This phase is characterized by huge investments. In the third phase, more and more players enter the technology field, competition becomes important and development speed of the technology decreases. In the last phase, the technology is mature, (nearly) everybody can use it, there are fewer margins and the technology should be replaced by a new one. Many of the SSL technologies have meanwhile reached maturity. Where are the upcoming technologies, what will be the next S-curve? Looking at technology discussions and lectures at LpS 2017 I tried to find answers to these questions. Read more »

LpR Article | Technologies | Jan 15, 2018

LiFi - What It Is, How It Works, What It Provides, How to Apply, and Its Future Prospects

LiFi - What It Is, How It Works, What It Provides, How to Apply, and Its Future Prospects The acronym LiFi (Light Fidelity) was born at the beginning of the 2010s. Its name derives from the very well-known WiFi (Wireless Fidelity). The term VLC (Visible Light Communication) is used in the restricted instances of visible light. Mr. Luc Chassage who works for Oledcomm and the Versailles University is also Scientific Committee President of the Global LiFi Congress that offers 20 lectures dealing with all aspects of LiFi. He is a profound expert in this technology field. Mr. Chassage explains the functionality, pitfalls and hurdles to overcome, the disadvantages and advantages, and best practice to apply LiFi. Read more »

LpR Article | Research | Jan 15, 2018

Thermal Issues Posed by Compact Packaging and IoT for Next Generation SSL

Thermal Issues Posed by Compact Packaging and IoT for Next Generation SSL Besides general lighting, LEDs are penetrating many areas. At the same time, Internet of Things (IoT) has been rapidly evolving. Added electronics are expected to add an additional 70% to overall heat generation. Therefore, solving thermal problems will become more important again; on a par with footprint area and cost. Prof. Mehmet Arik, Director of EVATEG Center for Energy Efficient Electronics and Lighting Technologies at the Ozyegin University, and Umut Zeynep Uras, master student at the Ozyegin University, present some of the current, local, hotspot thermal issues caused by tight packaging. The severity of the problem for future lighting systems with added IoT will also be discussed. Finally, possible technologies to meet those challenges will be shown. Read more »

LpR Article | Research | Jan 01, 2018

Hybrid Quantum Dot Light Emitting Electrochemical Cells

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 »

LpR Article | Research | Jan 01, 2018

Color Reproduction and Measurement of 3D Objects

Color Reproduction and Measurement of 3D Objects CIE Division 8 Image Technology is responsible for the study of the optical, visual and metrological aspects of the communication, processing, and reproduction of images, using all types of analogue and digital imaging devices, storage media, and imaging media. The Division is continually working on recommendations to improve color image reproduction techniques, including, for example, colorappearance models, color-difference evaluation and gamut-mapping algorithms. Current technology is able to transform color images from one digital medium to another, under various viewing conditions, while maintaining the appearance of each color in the image. This process has been applied in the graphic arts industry with great success. According to Kaida Xiao, Chair of CIE's Division 8 TC 8-17, the CIE standard observer and psychophysical data for color-appearance and color-difference modelling were developed using flat, 2D color samples. He explains that to meet the increasing requirements for color image reproduction for 3D objects, new research and recommendations are highly desired. Read more »

LpR Article | Applications | Dec 28, 2017

Interior Automotive Lighting Control Redefined

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 »

LpR Article | Event Post Show Report | Dec 13, 2017

LpS Gets a Younger Sibling to Foster a Holistic System Approach

LpS Gets a Younger Sibling to Foster a Holistic System Approach For the most part our readers are aware of the fact that the LpS has a strong focus on the component level, but after the 6th event, the Luger Research team realized that it was time to find a way to push the more holistic system approach. After much consideration and careful planning, the Trends in Lighting (TiL) Forum and Show was initiated and took place in conjunction with the LpS 2017. Arno Grabher-Meyer, Editor-in-Chief at LED professional took a close look at both exhibitions and the lectures to find out what the audience thought of the extension and broader outlook. Read more »

LpR Article | Quality | Dec 11, 2017

Avoiding Brightness and Color Mismatch with Proper RGB Gamut Calibration

Avoiding Brightness and Color Mismatch with Proper RGB Gamut Calibration For well over a decade, proponents of Solid-State Lighting (SSL) have been offering bullish forecasts concerning the adoption of LEDs for general and specialized lighting applications. Recent years have seen those rosy predictions come true, with LED lighting now almost completely dominating the market for new construction, retrofit, and many replacement lighting applications. For many of these applications accurate color calibration is required. Rood Bouten, CTO at Admesy, explains the reasons and how to perform a proper RGB gamut calibration. Read more »

LpR Article | Commentary | Dec 11, 2017

The Value of High-End Labs for High Quality Lighting

The Value of High-End Labs for High Quality Lighting With the relocation to the Augsburg site in 2015, the Osram laboratory equipment includes a number of integrating spheres of different sizes up to 3 meters in diameter, several goniophotometers A/B/C types, a rotary mirror light distribution meter and a hemispherical goniometer with a measurement radius of 2.65 meters, optical bench measuring systems with up to 35 meter measuring distance, corresponding high-quality photometric receivers and spectral radiometers as well as the necessary components for the electrical operation of lamps - according to customer or standardized specifications. Read more »

LpR Article | Trends | Nov 30, 2017

SoC Technologies in Lighting - Today’s Landscape and Tomorrow's Practices

SoC Technologies in Lighting - Today’s Landscape and Tomorrow's Practices A system-on-chip (SoC) quite suddenly became an important component in the lighting industry, fueling IoT innovation and opening new opportunities, while at the same time bringing disruption and new challenges. With rapid advancements in wireless communication, the impact of connected technologies on the lighting business will only keep increasing. This means deeper integration with SoCs and more attention from silicon vendors as they start competing for market share in this promising segment. But what is the current state of SoC design from the lighting perspective? Are chipmakers keeping up with the growing expectations for wireless lighting control solutions that are mature and truly reliable? When developing its complete Bluetooth software stack for professional lighting, Silvair worked with a number of different SoCs. Therefore, Piotr Winiarczyk, Wireless Solution Architect, and Szymon Rzadkosz might have found the answers to these questions. Read more »

LpR Article | Technologies | Nov 09, 2017

LED Driver Miniaturization - Opening New Opportunities for Solid State Lighting

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 | Research | Nov 02, 2017

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

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 »

LpR Article | Sep 25, 2017

Trends in Horticulture Lighting

Trends in Horticulture Lighting Cree has been a leader in general lighting applications for over 20 years and has customers ranging from restaurant chains to global government agencies. Paul Scheidt began his career in Cree in 2005, working on the development of their lighting applications. During this time, he has seen an increase in the horticulture lighting application. LED professional spoke to Paul Scheidt about horticulture lighting and what he thinks is behind this recent trend. He also shares his views of what he thinks the future holds for both Cree and horticulture lighting applications. Read more »

LpR Article | Quality | Sep 25, 2017

Lighting to Achieve Optimal Appearance

Lighting to Achieve Optimal Appearance Visual appearance of an object or space depends on the characteristics of the lighting applied. The objective definition of light quality often doesn’t tell the whole story. Light intensity, its spectral composition and distribution in space, as well as individual preference, must be considered. Nevertheless, aiming for the absolute optimum is only recommended when private rooms are concerned. As visual appearance is key in driving consumer demand, it is important to tune the light to maximize effectiveness and visual pleasure for most consumers. Markus Reisinger, owner and CEO of the Lighting Research Studio, discusses this complex situation with examples. Read more »

LpR Article | UV | Sep 25, 2017

Issue 63 | Challenges in UV Measurement

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 | Technologies | Sep 25, 2017

Quantum Dot Based White LEDs for General Illumination

Quantum Dot Based White LEDs for General Illumination Colloidal quantum dot based white LEDs can be integrated into commercial products meeting the stringent reliability requirements for general illumination and providing LED efficiency gains of 5% to 15% over commercial phosphor based LEDs at CCT’s ranging from 5000 K to 2700 K. Unlike earlier demonstrations, the QD material is applied in an on-chip configuration resulting in drop-in fit, form, and function compatibility to existing LED based luminaires and lamps. Ken T. Shimizu, Director, Novel Technologies and Devices, Research and Development, M. Böhmer, D. Estrada, S. Gangwal, S. Grabowski, H. Bechtel, E. Kang, K. J. Vampola, D. Chamberlin, O. B. Shchekin, and J. Bhardwaj from Lumileds showcase the advantages of on-chip QD LEDs: A commercial lamp at 3000K color temperature and 90 CRI is substituted with QD based LEDs resulting in a system level efficiency gain up to 17%, attributed to the reduced blue LED droop from the lower drive current and the lower heat sink temperature when compared to the standard phosphor based LED lamp output. Read more »

LpR Article | Research | Sep 25, 2017

Challenges when Designing LED-Based Illumination Systems in Medical Applications and Diagnostics

Challenges when Designing LED-Based Illumination Systems in Medical Applications and Diagnostics LEDs have become indispensable in medical technology and dentistry. But the requirements placed on these lighting products are very high: Minimized size, high, application specific color rendering index, efficient temperature management, usability and excellent disinfection opportunities are all extremely important. Prof. Paola Belloni from the Steinbeis Transfer Center Illumination Optics and Lighting Engineering and Furtwangen University, and Alexander Gärtner from the Faculty of Mechanical and Medical Engineering of the Furtwangen University discuss the requirements for different applications such as endoscopy, surgeries, dental devices, and photodynamic therapy. Further topics are the development of a self-disinfecting operation interface with edge-lit UV-A LEDs, and a new optimization approach, taking into account the reflection and absorption properties of human tissues. Read more »

LpR Article | Research | Sep 25, 2017

Measurement of Angular and Spatial Resolved Spectral Rayfiles

Measurement of Angular and Spatial Resolved Spectral Rayfiles The enhanced complexity of modern lighting systems has increased the importance of realistic light source models during the optical design process of LED-based luminaires. I. Rotscholl, Research Associate, K. Trampert, C. Neumann, I. Leopoldo Sayanca from the Karlsruhe Institute of Technology, U. Krüger and F. Schmidt from the TechnoTeam Bildverarbeitung GmbH, propose a method to enhance the often used LED light source model “rayfile” towards a “spectral rayfile”. A spectral rayfile would be a model that associates each ray with its own spectrum and therefore describes varying spectra as a function of angular direction and spatial starting position. The PMBS (physical motivated basis spectra) method is based on the assumption that each LED spectrum consists of a weighted sum of individual basis spectra, for instance those of individual semiconductors and phosphors. There is no need for any special measurement equipment but a classic nearfield goniophotometer and some off-the-shelf optical filters. This method requires at least one spectral measurement and just a minimum of goniophotometric measurements with different optical filters. Finally, the authors demonstrate the potential of this method by applying the concept on a typical LED and compare the results to the often used Blue/Yellow approach in terms of accuracy and applicability. Read more »

LpR Article | Research | Sep 25, 2017

CIE Calls for Focused Research Efforts to Support Healthful Lighting Recommendations

CIE Calls for Focused Research Efforts to Support Healthful Lighting Recommendations Not so long ago, vision scientists thought that light detection - photoreception - was exclusively performed by rod and cone cells in the retina. Photobiologists, however, conclusively demonstrated otherwise with the identification of the intrinsically photoreceptive retinal ganglion cells (ipRGCs) [1]. Whereas rods and cones detect pattern and color, and send this information to the visual cortex, ipRGCs (of which we are learning there are several subtypes) detect irradiance, and route their information to many brain structures. The most thoroughly studied of these is the suprachiasmatic nucleus of the hypothalamus, location of the central circadian clock, where the light and dark signals trigger the offset and onset of production of the hormone melatonin. As shown in figure 1, however, ipRGCs also project to other structures, about which, as yet, we have little information. Read more »

LpR Article | Sep 14, 2017

Technology Challenges in Professional Tunnel Lighting Applications

Technology Challenges in Professional Tunnel Lighting Applications The guide for tunnel lighting CIE 088:2004 is the most established international standard for the illumination of road tunnels. However, Switzerland’s ASTRA (Bundesamt für Strassen) and the ASFINAG in Austria both provide guidelines that go well beyond these requirements. Maximilian Herzig, Product and Key Account Manager Lighting at SWAREFLEX GmbH shows solutions to satisfy these requirements and explains why the commonly used value of "lumen per watt" is not a perfect method of evaluating system performance and efficiency. Read more »

LpR Article | News-Spot | Sep 13, 2017

Luger Research Creates an Active Network to Secure the Future of Innovation in Lighting: The First Meeting Will Take Place at the LpS 2017

Luger Research Creates an Active Network to Secure the Future of Innovation in Lighting: The First Meeting Will Take Place at the LpS 2017 Luger Research establishes the first scientific lighting partnership network for research experts and leaders in the lighting industry. The scientific partnership has been created to form an active network that will strengthen and build the connections between universities, research laboratories and industry. The scientific partnership’s mission is to enable and secure the continued development of innovation in lighting technology. Read more »

LpR Article | Research | Sep 13, 2017

CIE Research Strategy on Defining New Calibration Sources and Illuminants

CIE Research Strategy on Defining New Calibration Sources and Illuminants In photometry and radiometry, traceability of measurements requires appropriate calibration sources and transfer detectors. A major challenge is the technological revolution of lighting products towards LED lighting and the ban of incandescent lamps. This raises concern about the availability of incandescent photometric standard lamps in the future while the prices of such standard lamps are already increasing. In addition, calibration conditions should ideally be chosen to be as close as possible to the measurement conditions. Furthermore, the number of LED lighting measurements in laboratories and in the field has significantly increased, while the calibration of photometers is still done using incandescentbased standards. Therefore, it is important to investigate the pros and cons of replacement of conventional standard lamps with new solid-state technology. Peter Blattner and Tony Bergen, Division 2 Director and Secretary respectively, explain how CIE has defined the research topic “New Calibration Sources and Illuminants for Photometry, Colorimetry, and Radiometry” to address these concerns. Read more »

LpR Article | Research | Sep 07, 2017

Variability in LED Production and the Impact on Performance

Variability in LED Production and the Impact on Performance LEDs are subject to manufacturing deviations, which have an impact on the end product. Benoit Bataillou and T. Merelle, guest authors from Pi Lighting, review the surprisingly large impact on LED performance and light quality. They used traditional as well as modern indicators like CRI and TM-30 as well as the latest circadian indices to measure. The results are explained by spectral modeling and a variability study. They show the large impact on CRI, even with small deviations inside the same bin. Read more »

LpR Article | Research | Aug 24, 2017

Smart LED System in Package through Wafer Level Integration Approach

Smart LED System in Package through Wafer Level Integration Approach It is believed that LEDs will dominate all lighting applications in the near future. Integration and packaging are the two critical issues that, if resolved, will enable efficient and reliable solutions for lighting requirements. Z. Kolahdouz, H. van Zeijl, and G. Q. Zhang from the Institute of Microsystems and Nanoelectronics (DIMES) at the Delft University of Technology, and M. Kolahdouz from the Thin Film Laboratory and Nano-Electronics at the Department of Electrical and Computer Engineering of the University of Tehran show that wafer level packaging is a promising method to ensure lower cost, higher scale, and superior yield. A new integration approach of a smart unit of LED lighting is introduced: LED System in Package (SiP). Read more »

LpR Article | Research | Aug 10, 2017

Ultrathin Direct-Lit LED Module with Beam Shaping Thin-Film Optics

Ultrathin Direct-Lit LED Module with Beam Shaping Thin-Film Optics Thin, high quality, LED light panels are still a challenge. LED professional’s scientific partner, CSEM, investigated and developed a new approach with its partners, GAIKER-IK4 and BASF-SE. The authors, Oscar Fernández and Rolando Ferrini, from CSEM, Leire Barruetabeña, from GAIKER-IK4, and Sorin Ivanovici from BASF SE, present a solution that uses low-cost and spectrally poor, ultra-cool white LEDs in conjunction with optical color conversion foils, to transform the output to a high-quality light. They also describe a combination with added lime and red LEDs for a color tunable solution. Read more »

LpR Article | Research | Jul 27, 2017

New Glass-Based Phosphors for White Light-Emitting Diodes

New Glass-Based Phosphors for White Light-Emitting Diodes Phosphors were always the key component of high quality white LED light. With the increased effîcacy and the higher power capabilities of blue high power LEDs, the phosphors become even more important for reliability, color consistency and overall light quality. Franziska Steudel, Florian Wagner, A. Charlotte Rimbach, Bernd Ahrens, Peter W. Nolte and Stefan Schweizer, scientists at the Fraunhofer Application Center for Inorganic Phosphors, a Branch Lab of Fraunhofer Institute for Microstructure of Materials and Systems IMWS, investigated different glass and ceramics based phosphors for white LEDs. Read more »

LpR Article | Research | Jul 17, 2017

Roadway Lighting Optics for Environment Adaptive Spatial Light Distribution

Roadway Lighting Optics for Environment Adaptive Spatial Light Distribution Roadway lighting for different environmental conditions is a challenging task. But even more challenging is to find a solution with outstanding task efficiency for both dry and wet tarmac surface conditions. The drawback of these types of solutions is that they are usually made up of two different lighting systems. Since the two systems are not usually used to an equal degree, they age at a different rate. Solving this problem is very complex. Viktor Zsellér, PhD student, and Dr. Krisztián Samu, Senior Lecturer, both from the Budapest University of Technology and Economics, propose an optical system that solves this conundrum. Read more »

LpR Article | Jul 13, 2017

Enabling Total Control in the Next Generation of Outdoor Lighting

Enabling Total Control in the Next Generation of Outdoor Lighting Outdoor lighting is certainly one of the applications with the greatest potential for energy saving. Although many approaches are discussed, they all end up with a smart lighting solution. In order to accommodate this, intelligent software and electronics are required as well as standardized, robust interfaces. Ronald Weber, Global Industry Manager, Building Automation and Benjamin Nelson, Business Development Manager, Intelligent Buildings, both from TE Connectivity, present a Zhaga compliant solution. Read more »

LpR Article | Research | Jun 22, 2017

CIE Fosters Co-Ordination of Global Research and Standardization on Temporal Light Modulation

CIE Fosters Co-Ordination of Global Research and Standardization on Temporal Light Modulation Dr. Jennifer Veitch, recently convened the CIE Stakeholder Workshop for Temporal Light Modulation Standards for Lighting Systems. Below is the exclusive report she provided on the workshop findings and the attitude of the CIE towards this important issue. Read more »

LpR Article | Technology | Thermal Management | Technologies | Jun 15, 2017

Looking for the Best Thermal Solution for CSP Module Designs

Looking for the Best Thermal Solution for CSP Module Designs Chip Scale Package (CSP) LED technology is not new but while it has been used for a while in TV backlighting applications, it is relatively new to lighting applications. In many respect CSPs are a new world for lighting module manufacturers as they are smaller, usually don’t have any ESD protection, have different light distribution, and, last but not least, have a smaller heat dissipation area. The latter asks for re-thinking the traditional thermal design for modules. Dr. Giles Humpston, Applications Engineer at Cambridge Nanotherm, explains in detail why CSP LEDs present a significant thermal challenge for module designers and outlines some fundamentals in calculating the thermal flow required to keep CSP LEDs cool. Read more »

FEATURED

GRE Alpha Introduces ENO-DIM EnOcean Wireless Dimming Module

GRE Alpha Introduces ENO-DIM EnOcean Wireless Dimming Module GRE Alpha announced the release of its cutting-edge ENO-DIM dimming module with integrated EnOcean technology. The spring-loaded terminal simplifies installation and is compatible with any EnOcean-enabled wireless switch. With the ready to install dimming module, it's just plug and play. The ... Read more »

EDITORIAL

LiFi - What It Is, How It Works, What It Provides, How to Apply, and Its Future Prospects

LiFi - What It Is, How It Works, What It Provides, How to Apply, and Its Future Prospects The acronym LiFi (Light Fidelity) was born at the beginning of the 2010s. Its name derives from the very well-known WiFi (Wireless Fidelity). The term VLC (Visible Light Communication) is used in the restricted instances of visible light. Mr. Luc Chassage who works for Oledcomm and the Versailles ... 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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