Articles & Interviews

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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 »

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 »

Resources | LpR Article | Quality | Perception | Sep 12, 2017

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 »

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 »

Resources | LpR Article | Commentary | Test Equipment | Oct 31, 2017

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 »

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 »

Resources | LpR Article | Tech-Talks Bregenz | Quantum Dots | Oct 31, 2017

Tech-Talks BREGENZ - Ken T. Shimizu, Research & Development Director, Lumileds

QDs have been a hot topic in lighting for a while already, but up until now they haven’t been adopted on a large scale in lighting. The adoption began in display devices because some of the technical issues were of less concern in this application. With continuing development, QDs are now also becoming interesting for general lighting applications. Ken Shimizu, Director of Novel Technologies and Devices, Research and Development at Lumileds, attended the LpS in Bregenz and made a presentation about the company’s QD technology. In this interview he gives some background information about the QD program and future steps. 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 »

Resources | LpR Article | Research | Thermal Management | Oct 31, 2017

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 »

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 »

Resources | LpR Article | Technologies | LiFi | Oct 31, 2017

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 »

A New Technology Is Changing the Tunable White Solutions

Tunable white LEDs are one key element of human centric lighting. Until today, different solutions are currently available but none of them is easy to apply or cost effective enough to speed up the diffusion of human centric lights in building projects. A new approach for tunable white solutions is able to provide flexible lighting for multiple occasions without sacrificing output or going over project budget. Phil Lee, Senior Lighting Engineer from Meteor Lighting will compare this new technology, called ColorFlip™, to conventional tunable white solutions, and talk about current tunable white issues. Read more »

Resources | LpR Article | Quality | Optics | Oct 31, 2017

Glare Reduction Made Easy

A pleasant lighting atmosphere due to low glare at the workstation is not only pleasant and performance-enhancing, but also legally required according to EU standard EN 12464-1. But what does “glaring” mean here? Dr. Claudius Noack, Technical Director at NORKA Leuchten, explains if luminaires with the same luminous flux are glaring to the same degree and if the same luminaires are glaring to the same degree at different workstations. He answers the questions of what a manufacturer does and if manufacturers are lying to themselves and therefore to their customers when providing information on the glare rating. Read more »

Resources | LpR Article | Environment | Oct 31, 2017

A World of LED Lights - The Cost of Waiting

Today, LEDs dominate the lighting domain. They are efficient and manufacturers understand how to implement them for different lighting applications. While energy efficiency is rather well understood, the impact of the adoption speed is rarely discussed is. Benoit Bataillou, guest author from Pi Lighting, will have a look at the environmental cost of LED production versus the significant energy savings that a full transition to LEDs would bring. In a fictive scenario, he assumes that a transition takes place in a heartbeat today and compares that with the usually supposed scenario of a full transition to LED lights in 2025. Read more »

Measurement Seminar – from SSL to Displays

For the third consecutive year, Instrument Systems invited engineers from all industries that deal with light measurement of SSL products and different kinds of displays to their seminar. LED professional’s Editor in Chief, Arno Grabher-Meyer, was also pleased to receive (and accept) an invitation. In this article he shows what attendees can expect, who might find this event of interest, who would benefit the most and who should definitely not miss the next opportunity to attend. Read more »

Resources | LpR Article | Commentary | Trends | Jan 15, 2018

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 »

Resources | Tech-Talks Bregenz | Research | Light Generation | Jan 15, 2018

Tech-Talks BREGENZ - Julia Frohleiks, Researcher, University of Duisburg-Essen

In his commentary on technical progress and innovation, Dr. Sejkora said: “In the early stage, in the first phase of its life cycle, technology is mainly driven by fundamental research.” He went on to say that we can never predict how a technology will develop. Researchers from the University of Duisburg-Essen, working in the Nano Energy Technical Center (NETZ), worked on this type of fundamental technology and their submission received the LpS 2017 Scientific Award. Ms. Julia Frohleiks, a Ph.D. student, was a major contributor to this research in the group led by Dr. Ekaterina Nannen and accepted the award in Dr. Nannen’s name. In the following interview she gives some background information and discloses future research possibilities. Read more »

Optimization of Freeform Optics Using T-Splines in LED Illumination Design

Freeform optics is the game changer in the illumination industry in terms of its ability to redirect the light into the target area. Non-Uniform Rational B-splines, commonly known as NURBS are widely used to represent freeform curves and surfaces. There are certain optical systems where local modification of the surface is necessary during the design or optimization phase. In such cases, NURBS cannot offer such transformations. But a new mathematical representation called T-splines make this feasible. Though its potentiality is well described, this has not been implemented in any optimization routine so far. Annie Shalom Isaac, Jiayi Long and Cornelius Neumann from the Karlsruhe Institute of Technology demonstrate the advantage of the local refinement ability of T-splines by implementing it in the optimization routine and the results are evaluated. Results show that T-splines provide more uniform and homogenous light distribution as compared to NURBS at a faster convergence rate. This makes optical design or optimization using T-splines an intuitive approach for future freeform design tasks. Read more »

Repro-Light - Looking for a Sustainable and Modular Luminaire Architecture

The Repro-light project aims to re-conceptualize the European lighting industry towards more sustainability and competitiveness in terms of production and time to market. This will be achieved through the implementation of modular luminaire architecture and a smart production scheme, demonstrated by the development of a reconfigurable customized LED luminaire designed to improve the customers’ health. Read more »

Resources | LpR Article | Technologies | Applications | Jan 15, 2018

Multi-Pixel LED Technology Opens New Horizons for Smart Lighting Applications

The evolution of Multi-Pixel LED technology has initiated a giant leap in the development of intelligent lighting systems which are most visible in the automotive industry. Now the first hybrid LED provides smart headlights with more than 1000 individually controllable pixels. Ralph Bertram, who is working on advanced LED device concepts, and Norbert Harendt, who is developing optics solutions for general lighting at Osram Opto Semiconductors, show that automotive lighting is just one of the potential areas in which intelligent selective pixel control can be applied. Options for the use in general lighting, such as information display for outdoor, indoor, retail or industrial applications, are very versatile. Read more »

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