Articles & Interviews

Resources | LpR Article | Feb 20, 2021

Reader's Question About "Short-Pulse Testing"

In reference to the article "Short-Pulse Testing Eliminates Self-Heating Errors to Produce True L-I Graphs" in issue LpR#83, a reader has asked why one measures with these short pulses, since this differs very much to the conditions in real application. Read the author's answer below. Read more »

Resources | LpR Article | Technologies | LED Drivers | Jan 13, 2021

How to Increase the Efficiency of Two-Stage Drivers

In this article, Dr. Weirich from Infineon Technologies, describes a simple method for increasing the efficiency of drivers that can operate with LED engines with a wide range of current and power levels, at virtually no effort. In addition, the method allows for using smaller inductors in the buck stage, leading to lower cost and potentially, smaller size. Read more »

Research Reports | Sustainability | Dec 15, 2020

Repro-light Consortium Concludes

Aldrans, Tyrol, November 2020 - The European research project Repro-light concludes after a three year journey which began in 2017. The consortium set out with the aim of supporting the European lighting industry in moving towards a more sustainable and competitive future. The project harnessed innovative technologies and materials to develop intelligent modular luminaires with matching smart production processes. The main components of these luminaires are interchangeable and configurable for the respective application (e.g. different LED modules and optics), and their software can be updated accordingly. The LED luminaire can change from a disposable object, into a customisable and sustainable product, with a high function value. Read more »

Resources | Full Spectrum LEDs | Jürgen Honold | Opinions | Nov 30, 2020

Tech-Talks BREGENZ with Jürgen HONOLD, Dipl.Des.(FH)

At LpS 2019, Jürgen Honold, Dipl.Des.(FH), and his co-presenter Dr. Martijn Dekker, held a very interesting and remarkable lecture about photobio-modulation (PBM). LED professional wanted to learn more and asked Jürgen Honold for an interview. As Technical Fellow, he is responsible for Seaboroughs' advanced lighting research and development and exactly the right person to talk with when it comes to HCL and related technologies and applications. Dr. Martijn Dekker, CEO of Seaborough accompanied him and gave an introduction with additional insights into Seaborough and the company's structure and strategy Read more »

Discomfort Caused by Glare from Luminaires with a Non-Uniform Source Luminance

Glare and the resulting discomfort are a persistent issue in lighting that became even bigger with the introduction with LEDs as a light source. While the UGR method is well established, it is sometimes heavily discussed if it is appropriate for SSL. The limitations of the UGR method need to be understood. Peter Thorns BSc(Hons), CEng, FCIBSE, FSLL, explains these limitations and consequently describes the research and how to apply correction measures. Read more »

Adopting an LED More Suited to Circadian Entrainment

Since the introduction of LED lights, a lot has been said about risks of blue light for ocular health on the one hand, and the opportunity of circadian entrainment, on the other hand. While a controversial discussion on the first topic is ongoing, the second topic is well accepted. To solve both issues, Bill Chan, President of LiteController Inc. proposes the application of 465-470nm pumped phosphor converted white LEDs with a content of 86% - 92% blue-turquoise light and 8% - 14% blue-violet light. In the article he concentrates on the second topic and proves the benefit of regulating the circadian entrainment more efficiently, maintaining a high typical efficacy of 150 lm/W and good color rendering of CRI 80+ ideally supporting the WELL Building Standard. Read more »

Kenneth Martin from Zumtobel about Comfortable Lighting

Kenneth Martin has been specifying, qualifying an developing components and characterization setups for LED light sources within the Zumtobel Group since 2006. With his expertise on spectral measurements and applications, he supports integrative lighting solutions topics. He gathered valuable knowledge in physics and optical system engineering while studying at the University of Applied Sciences RV-Weingarten, during the internships at a quality assurance department of a reflector aluminum manufacturer and the optical development department of Zumtobel. He combines his enthusiasm for lighting and sustainable construction engineering with a DIY philosophy. Read more »

Offline Lighting Voice Controller — An Alternative to Voice Assistants

The historical evolution of light control by users started with a mechanical switch followed by potentiometer and dimming, touch panels and touch screens, gesture and movement detection control, and ending with voice. Voice control are mostly online speaker independent like Alexa, Google Home and Siri. But there are privacy and security concerns. Filip Michalski, Electronic Engineer, and Cezary Skotak, CEO, from Cezos describe a speaker independent offline voice controls system, explain the technology and discuss the pros and cons. Read more »

Paradigm Changes in Lighting Are Challenging Lighting Companies

Fabien Bubendorff has a Master in Electronic Engineering and has 10 years' experience in the lighting industry. He has spent more than 13 years living in China. He worked as a Product Manager for a Retail Lighting Company, for the Last 5 years he was responsible for Wever&Ducré as the Head of R&D in China and for the last years Head of R&D at XAL in Austria. Now he has founded an independent consultancy to support European Lighting Companies to deal with these future challenges. He specialized in finding the optimal balance between function and cost to increase product profitability. Read more »

TechTalks BREGENZ - Dr. Christoph Wächter, Senior Scientist at Fraunhofer IOF, Germany

Research topics have become more important with LEDs and LED lighting micro optics and freeform optics. A new approach based on an IP for a fly's eye condenser from 1928, filed by Zeiss Ikon AG that extends possibilities and allows for new applications was presented ‚at LpS 2019. The jury was so impressed with the paper that it won the Scientific Award 2019. Dr. Guenther Sejkora and Arno Grabher-Meyer from LED professional talked to Dr. Christoph Wächer, co-author and presenter of the paper about his approach, his career and work. Dr. Christoph Wächter is a senior scientist at Fraunhofer IOF. Read more »

A New LED Controller Technology to Expedite the Next Level of Smart Lighting

Lighting installations that use artificial lighting and often deemed more comfortable and energy efficient are generally referred to as "Smart Lighting". While no clear definition exists "Smart Lighting" has become a common catch phrase. Kurt Marquardt, Senior Director LED Lighting Systems and Product Marketing, Infineon Technologies has a more accurate definition. For him, the term "smart lighting" describes the capability of the lighting system to adapt automatically to the needs of the users and the room. He presents an alternative way to implement smart lighting systems, using the new XDPL8221 digital LED-driver IC [1]. Read more »

LpR Article | Research | Health + Environment | Environment | Jul 30, 2020

The Adverse Ecological Impacts of Light Pollution: LEDs' Role in Mitigation

With the negative effects of artificial light at night on ecosystems increasingly well-understood, attention is now turning to the ways in which these impacts can be mitigated through uptake of novel technology and lighting strategies. Dr. Callum J. Macgregor, post-doctoral research associate at the Department of Biology of the University of York, and Dr. Darren M. Evans from the School of Natural and Environmental Sciences of the Newcastle University, discuss the current evidence for costs and opportunities associated with uptake of LED lighting and highlight important directions for future investigation. Read more »

Temperature Profiling of Secondary LED Optics by Infrared Thermography

Over the last few years, the power density of white LEDs has increased dramatically. Whilst there are large efforts to optimize the thermal management and thus the temperature stability of the LEDs, less attention is paid to the temperature of the secondary optic. Peter W. Nolte, Franziska Steudel, Bernd Ahrens, Nils J. Ziegeler, Frank Drees, Horst Rudolph, and Stefan Schweizer from the Fraunhofer Application Center for Inorganic Phosphors, the South Westphalia University of Applied Sciences, and the Innovations-and Technologycenter GmbH, TRILUX Group respectively, have approached this issue. They investigated the temperature profiles of polymethyl methacrylate (PMMA) and polycarbonate (PC) secondary optics and they discuss the results. Read more »

On Life Cycle Assessment to Quantify the Environmental Impact of Lighting Products

The lighting industry has made great efforts to increase energy efficiency around the world with a strong participation from governmental organizations, multilateral organizations and agencies. However, energy consumption is not the only aspect that needs to be considered for transforming the lighting industry. Víctor Ferreira, Deidre Wolff, and Cristina Corchero from Catalonia Institute for Energy Research (IREC) will explore relevant environmental metrics to help inform the reader about circular economy and Industry 4.0 strategies to achieve a sustainable lighting product. Read more »

Resources | Tech-Talks Bregenz | Health + Environment | Quality | May 04, 2020

Tech-Talks BREGENZ - Prof. Ruairí O'Brien, Founder of Ruairí O'Brien Lighting Design

Ruairí O'Brien, associate professor and head of the Architecture and Visual design department at the German University in Cairo and CEO of Ruairí O'Brien. Architektur. Licht Raumkunst, surprised and delighted the audience with his lecture at LpS 2016 when he talked about allowing darkness. He expressed the same sentiments in a caption for a figure in the proceedings booklet: "The future in Dresden is not lighting excess - the future is Re-Darkness with intelligent SSL concepts." This year, Ruairí held two lectures at TiL in which he emphasized how important a thorough application of light is in respect to culture, ethics, and environment. In addition to his work, these interesting statements made it made a Tech-Talk Bregenz with him a top priority. Read more »

Resources | Commentary | Smart Lighting + IoT | Health + Wellbeing | May 04, 2020

Personal Lighting Profiles Might Be the Key to Creating a Natural "Work Light Balance"

Commentary from LpR 76: Henrik Clausen has been involved in lighting for over 30 years in both commercial and academic positions. In 1996, he became the Managing Director of Fagerhult Lighting in Denmark, and held that position until 2004, when he founded the Fagerhult Lighting Academy. In 2015 he also became Head of Research for Fagerhult. He holds a position as professor in Lighting Design at AAU in Copenhagen. He guest lectures at various Universities around the world. He speaks worldwide, primarily addressing the human and emotional aspects of light and lighting design. Read more »

Resources | Tech-Talks Bregenz | Wilfried Kramb | Opinions | May 04, 2020

Tech-Talks BREGENZ - Wilfried Kramb, Interior & Lighting Designer, a∙g Licht

TTB from LpR 75: The value of lighting design and light planning has always been underestimated, despite it becoming more important with the rise of Solid-State-Lighting. This is a fact that the public doesn't realize, even though the industry does. Digitalization, compared with the special properties of LED lighting and the aim of the lighting industry to establish their IoT hubs, is a new challenge. This is even more apparent when trying to integrate light sources directly in building structures. Responsibilities and tasks are no longer clearly separated between the different disciplines of architect, lighting designer, IT planner and electro planner. Guenther Sejkora and Arno Grabher-Meyer talked with Wilfried Kramb, owner and CEO of a·g Licht, about these tendencies and topic. Read more »

Resources | Commentary | Health + Environment | Quality | May 04, 2020

Providing Better Light Should Still be the Focus of the SSL Industry

Commentary from LpR 75: As President of Bardsley Consulting, Norman advises industry, government and academia on solid-state lighting, flat panel displays and energy efficiency, with special emphasis on diffuse lighting and organic electronics. He is a member of the Technical Advisory Team for the Solid-State Lighting Program of the US Department of Energy. Dr. Bardsley also acts as Chief Analyst for the International Solid-State Lighting Alliance (ISA) and is a member of the UNEP Expert Task Force on LED Lighting and Controls. Read more »

Resources | Commentary | UV | Disinfection | Feb 05, 2020

Selecting the UV LED Wavelength for Purification Applications

Patrick Durand is the Worldwide Technical Director at Future Lighting Solutions (FLS) with over 15 years of experience in the solid state lighting industry. Patrick leads the FLS Technical Marketing teams and FLS laboratory teams located in multiple regions around the world with the objective of providing world-class support to lighting OEMs in developing luminaires with the latest SSL technology from the light source to the complete system incorporating the LED driver, optic, thermal management and intelligent control solutions. 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 »

Transparent Material Considerations for UV Optics in Horticultural Lighting Applications

Advancements in UV LED technology have begun changing the horticultural lighting landscape. Research is still ongoing to discover the extent of benefits and best practices of using UV light in horticulture. Using optics in tandem with UV LED light systems can help reach performance goals and optimize growing. Although there are several UV- transmitting materials available, not all are equivalent or able to meet the requirements for UV applications. Justine Galbraith, glass engineer, and Sharayah Follett, market development manager at Kopp Glass, Inc. discuss the performance considerations of various UV-transmitting materials and how application challenges are addressed by integrating optical elements. Read more »

Hermetic Polymer-Free White LEDs for Harsh Environments

AlGaInN-based white LED can easily achieve lifetimes of up to 100,000 h depending on junction temperature and current density. However, state of the art silicone encapsulated LEDs with powder-based phosphors reveal a strong dependence of field lifetimes on environmental conditions such as humidity, corrosive gas and air pollutant exposure. Dr. Michael Kunzer, Group Leader LED Modules at Fraunhofer Institute for Applied Solid State Physics and his colleagues, Ralf Schmidt, Andreas Zibold, Vasileios Georgiou-Sarlikiotis, Michael Arnold and Isabel Kinski propose luminescent ceramics as an interesting alternative to polymer-dispersed phosphors. This provides entirely new opportunities for the manufacturing of white LEDs. The authors explain the properties and advantage of this hermetic, light converting cap material and how to completely avoid polymers. Read more »

A New Approach for Fast and Accurate Measurement of Light Emitting Diodes Junction Temperatures

LpR 73 Article, page 48: Junction temperature of LEDs is one crucial parameter to being thoroughly observed. In this paper, Ahmet Mete Muslu, Onuralp Isil and Prof. Mehmet Arik from the Energy Efficient Electronics and Lighting Technologies Center (EVATEG), Department of Mechanical Engineering at the College of Engineering Ozyegin Universitywill at first describe the importance of Tj for LED systems including RGB and white LEDs. Then they will present techniques from literature and recently in-house developed novel methods and a new Junction Temperature Measurement Device (EVAtherm). Results in selected general lighting and automotive lighting applications will be demonstrated. Read more »

Environment | Commentary | Resources | Health + Environment | Dec 16, 2019

Care, Caution & Awareness Are Needed When Using LED Lights

Kyra Xavia is a researcher, educator and investigative journalist based in New Zealand. Her roles as general secretary of the Light and Lighting Research Consortium (LLRC), delegate for the International Dark Sky Association (IDA), New Zealand Ambassador for Women in Lighting 2019, and co-leader of the Dunedin Dark Skies Group, involve educating decision-makers and the public about the importance of responsible lighting, nocturnal placemaking and the value of darkness. Recognised in New Zealand and abroad for her advocacy in these matters, Kyra has co-authored research papers and published articles specific to this subject. Kyra has recently been awarded with The Dark Sky Defender Award. Read more »

Resources | Tech-Talks Bregenz | Laser Technology | Dec 16, 2019

Tech-Talks BREGENZ - Julian Carey, Marketing Manager at SLD Laser

In 2016, Nobel Laureate, Professor Shuji Nakamura held a key note speech at LpS. As the founder of Soraa and SLD Laser, he named laser lighting as the next, innovative step and disruption in lighting. He emphasized the need to focus on light quality and the tailoring of LED lighting to the natural needs of humas, providing light that mimics sunlight as closely as possible. It was therefore self-evident that LED professional would invite Julian Carey, the Product and Technical Marketing Manager at SLD Laser, for a Tech-Talk when he was at the LpS 2018 in Bregenz. We asked him for an update on the status of laser lighting, business strategies and future prospects and how laser lighting has developed since Professor Nakamura's statements in 2016. 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 »

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 »

Resources | Commentary | Quality | Nov 15, 2019

Commentary: Providing Better Light Should Still be the Focus of the SSL Industry

J. Norman Bardsley, PhD - As President of Bardsley Consulting, Norman advises industry, government and academia on solid-state lighting, flat panel displays and energy efficiency, with special emphasis on diffuse lighting and organic electronics. Read more »

Tech-Talks BREGENZ - Dr. Scott Wade, Technical & Certification Manager, DiiA

Dr. Scott Wade has been the Technical & Certification Manager for DALI/DiiA since 2013 and has been an industry expert member of the IEC62386 standardization team for about 14 years. He was invited to hold a lecture at the LpS 2018 about the founding of DiiA for the purpose of taking over the DALI trademark from ZVEI and discussed measures that were taken to further develop the standard and its certification process and make the DALI concept future proof with DALI-2. Read more »

Resources | LpR Article | Research | Thermal Management | Sep 17, 2019

Thermal and Optical Challenges for SSL in Automotive Applications

LpR 72 Article, page 50: Solid State Lighting changed the lighting environment in automotive lighting almost more than in the field of general lighting. While efficiency of the devices increased and every few weeks new improvements are reported, thermal management remains crucial and a critical part of the system. Umut Zeynep Uras, Ahmet Mete Muslu and Mehmet Arik, from the Energy Efficient Electronics and Lighting Technologies Center (EVATEG), Department of Mechanical Engineering, College of Engineering at Ozyegin University, and Fatih Goren from the FARBA Corporation, explain the dependencies between photometric, electrical and thermal parameters of an automotive lighting application. Read more »