Articles & Interviews

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 »

Resources | LpR Article | Research | Micro-Optics | Aug 13, 2019

Semi-Empirical Characterization of Freeform Microlens Arrays

LpR 72 Article - page 42: Microlens arrays (MLA) have been used for imaging and non-imaging applications for a long time as cost-effective solutions. Non-symmetrical beam shapes require more advanced non-symmetrical freeform microlens arrays (FMLA). The required FMLA molding tools convey a high cost and an iteration process is required for the final design. Oscar Fernández, Tamara Aderneuer, Rolando Ferrini from the Centre Suisse d'Electronique et de Microtechnique, CSEM, and Julien Duchene from ANSYS proposed a method to overcome these limitations based on 3D surface sampling, computer generation of a ray-traceable model and ray-tracing performance simulation and demonstrate feasibility for several commercially available freeform asymmetric thin-film diffusers. Read more »

Applications | Smart Lighting + IoT | Resources | LpR Article | Aug 13, 2019

Technologies for Shared Office Space

LpR 72 Article, page 66: Shared office spaces are gaining popularity as a flexible, resource-efficient and creativity-inspiring way to work. The dynamic nature of such office spaces requires building automation and lighting control solutions that can quickly be deployed and easily be adapted to new office layouts. Matthias Kassner, Vice President Product Marketing at EnOcean GmbH, takes a look at different connectivity architectures (wired, wireless, hybrid) and protocols (Bluetooth, ZigBee, EnOcean, PoE) to assess their usability and show how minimizing the need for maintenance is a key for increasing profitability of service-based offerings. Read more »

Resources | Commentary | Aug 13, 2019

What the Heck Is Future Proof?

Commentary from LpR 72: The first time the question about future proofing LED systems came up seriously, was at LightFair 2018 when Siegfried Luger interviewed Patrick Durand. Since then, it has been the buzzword throughout the industry. Discussions concerning future proofing are often limited to wireless communications, IoT and some type of AI. But isn't there more? Read more »

Circadian-Friendly Light Emitters: From CCT-Tuning to Blue-Free Technology

Common levels of blue radiation are sufficient to disrupt the circadian cycle, calling for blue-depleted emitters in the evening. Most current solutions employ low-CCT and suffer from poor light quality. Aurelien David, chief scientist at Soraa explains the melanopic lumen and its possible sources of inaccuracy related to the uncertainty in assessing the circadian action spectrum. In addition, he also discusses the concept of a blue-free emitter with minimal melanopic lumen at very low CCT and how such a spectrum providing a good light quality can be optimized. Read more »

Flex LED Based Smart Light System for Healing of Chronic Wounds

LpR 71 Article - page 48: Chronic wounds are notoriously challenging to treat, because they do not follow the typical healing process or time-frame. The resulting burden is significant, affecting over 40 million patients. Blue light is known for its anti-microbial and anti-inflammatory effects in the initial stages of the healing process. David Kallweit, researcher at CSEM, reports about the joint development of a chronic wound treatment device with their MEDILIGHT partners, URGO RID, University of Heidelberg, SignalGenerix, Microsemi, Technical University of Berlin, and Amires. He furthermore shows how it works and discusses future prospects. Read more »

Medical | Tech-Talks Bregenz | Resources | Health + Environment | Jul 29, 2019

Tech-Talks BREGENZ - Dr. Octavio Perez, Adjunctant Researcher, Mt. Sinai Hospital

Dr. Perez received the LED professional Scientific Award 2018 for his paper on "Light and ED Clinical Wellness and Performance Improvement", which was published in LpR 70. The evaluation jury had the following to say about why they selected his paper: "The paper is based on the clear definition of the research question, hypothesis and objective of the research. The methodology of the screening study is described in detail and both subjective and objective parameters have been measured. Although Emergency Department lighting is a very special application, the paper provides interesting results." This interview provides background information on Octavio Perez, his work in general, his opinion on human centric lighting risks, opportunities and applications and how he became involved in this interesting research topic. Dr. Perez also provides additional details about the presented paper. Read more »

Technologies | Smart Lighting + IoT | Resources | LpR Article | Jul 29, 2019

Voice Controlled Lighting that Protects Privacy and Data

LpR 71 Article - page 54: Intelligent lighting systems undoubtedly offer high comfort and energy efficiency. But especially conventional voice control systems like Amazon Alexa, Apple Siri or OK Google, with connected lamps and lighting fixtures are also becoming targets for uninvited guests. The benefits and technology of a new approach offering local voice control and artificial intelligence will be explained by Genia Shipova, Director Global Communications at Snips. Read more »

Resources | Commentary | May 16, 2019

Well-Being, Light and Exhibition Lighting

Commentary from LpR 71: Well-being is the state of feeling healthy and happy, a good or satisfactory condition of existence, including the emotional and psychological sphere. In 1810, Goethe published a theory based on a human-based approach, combining visual appearance with harmony, culture, sensations and psychology. His color wheel was entitled "allegorical, symbolic, mystic use of color" and was composed of six hues, i.e. red (the beautiful), orange (the noble), yellow (the good), green (the useful), blue (the common) and violet (the unnecessary). The position on the wheel was harmonically relevant and in particular the colors in opposite position generated a strong psychological contrast and were called "opposite colors". Primary colors were yellow, blue and red, and the opposites were green, violet and orange, respectively. Goethe's wheel and the particular matching of opposites soon became popular and was used by the Impressionism movement, especially by Vincent van Gogh and Claude Monet. In this artistic movement, the special impact given by the combination of opposite colors were deliberately aimed to create special psychological effects and sensations. Read more »

Healthy Light - LED Technology for Health and Care Applications

The right light, at any time during the day or night, is absolutely essential for health and well-being especially in health and care applications. Peter Haumer, Head of Technical Sales at Lumitech/Kiteo reveals why, besides full spectrum and high color rendering, mimicking real daylight conditions with extended daylight curves, a direct and an indirect component (CCT 1.800–16.000 K), are essential. The article discusses the benefits that can be derived from special colors for medical staff, patients and residents. 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 »

Melanopic Green - The Other Side of Blue

LpR 71 Article - page 74: For years now, there has been a controversial discussion about the amount of blue light in LEDs. Medical studies have shown that, depending on the amount, blue light at night disrupts the circadian rhythm. As a result, warm white (<3000 K) light sources are often touted as a solution for street lighting as well. Ian Ashdown, P. Eng. (Ret.), FIES Senior Scientist at SunTracker Technologies discusses whether or not it is sufficient to only look at the CDT or if other wavelengths and aspects should be considered. Numerous medical studies have shown that exposure to blue light at night suppresses the production of melatonin by the pineal gland in our brains and so disrupts our circadian rhythms. As a result, we may have difficulty sleeping. It is therefore only common sense that we should specify warm white (3000 K) light sources wherever possible, especially for street lighting. - True or false? Read more »

User Evaluation of the OpenAIS Pilot Installation

The OpenAIS project (2015-2018) has developed an open IoT lighting solution to enable a wider community to deliver the smartness of light, allowing easy adaptability to cater for the diversity of people and demands. The project is a cooperation between seven leading companies in the European industry and two academic partners: Signify, Zumtobel, Tridonic, Johnson Controls, Dynniq Belgium, NXP, ARM, Eindhoven University of Technology. Thomas van de Werff, Harm van Essen and Berry Eggen from the Eindhoven University of Technology describe the evaluation results of the pilot installation in a real office building in Eindhoven (The Netherlands), a former Philips factory. Read more »

Resources | LpR Article | Horticulture | Applications | Mar 28, 2019

Enriching Horticultural Lighting for Faster Growth and Better Crops

Horticulture lighting is no new lighting application, but it gained momentum with the introduction and evolution of LED lighting, and it is meanwhile one of the fastest growing markets in lighting. Dr. Richard Blakey, Application Engineer at Würth Elektronik eiSos, explains how LED-based horticultural lighting can deliver even bigger advantages for commercial growers by introducing additional wavelengths that increase photosynthetic response - like Würth Elektronik's new members of the WL-SMDC SMD Mono-Color Ceramic LED Waterclear family that is used as a reference in the article. Read more »

48 VDC Integrated Drivers Offer New Options

LpR 70 Article, page 102: In the telecommunication and IT businesses, especially, 48 VDC grids have become quite popular. This growing global trend to facilitate direct current (DC) power supply in building "microgrids" presents new opportunities for solid state lighting designers. TE's Lighting Industry Manager, Ron Weber, and Global Product Manager, Scott Hamilton, describe how LED lighting fixture designers can now design luminaires around a 48 VDC constant voltage input, available to take advantage of the benefits of a low voltage DC distribution grid in a building. Read more »

Standardized Programming of Lighting Components Using NFC Technology

LpR 70 Article, page 88: NFC programming of LED drivers is rapidly gaining popularity as a fast, feature-rich, flexible and easy method to set the operating characteristics of LED drivers inside luminaires. Arnulf Rupp, Chair of MD-SIG, describes how the MD-SIG specification for NFC programming of lighting components makes it easy for luminaire manufacturers to use NFC programming in a production line where multiple brand drivers are used one after the other. Read more »

Bluetooth Mesh Protocol as Applied to Lighting

Little more than one year ago, Bluetooth SIG released the Bluetooth Mesh standardization. Meanwhile, it has become widely adopted and is also one of the favorite systems for lighting controls. Russ Sharer, Vice President of Global Marketing and Business Development for Fulham, starts with an explanation of the Bluetooth Mesh protocol as applied to lighting control and defining its key elements. In a second portion of the article, he answers questions that lighting control evaluators could be asking their vendor. Read more »

Resources | LpR Article | Research | Environment | Mar 26, 2019

When Nights Are No Longer Dark: Effects of Artificial Light at Night on Agroecosystems

In recent decades, artificial lighting has become an integral part of the modern world. While the use of artificial light at night (ALAN) greatly benefits people, it often has unintended, negative consequences for wildlife and ecosystems. In particular, the increasing use of LED lighting raises ecological concerns due to its high content of blue light, to which many organisms are sensitive. Dr. Maja Grubisic, Researcher at the Leibniz-Institute and Guest Lecturer at Free University Berlin discusses how ALAN can directly and indirectly influence agroecosystems, with potential consequences for food production and biodiversity. Given the current lack of integrative studies on this important topic, the better understanding of effects of ALAN in agroecosystems is urgently needed. Read more »

Resources | LpR Article | Research | Environment | Mar 26, 2019

Hazard or Hope? LEDs and Wildlife

LpR 70 Article, page 52: The introduction and widespread uptake of LEDs as outdoor lighting has caused no small amount of concern amongst conservation biologists. The prevailing impression that LEDs are always blue-white is well founded as adoption of LEDs for streetlights were invariably high color temperatures and with the deterioration of phosphors the blue wavelengths penetrated even more. But LEDs do have characteristics that differentiate them from other light sources and may allow for the reduction of environmental effects of lighting on species and habitats: direction, duration, intensity, and spectrum. Travis Longcore, Assistant Professor at the University of Southern California's School of Architecture, sheds light on all these aspects. Read more »

Lighting and Emergency Dept. Clinician Wellness and Performance Improvement

LpR 70 Article, page 38: Short wavelength ("blue") light is known for its strong impact on humans covering "visual" function, wellness and performance of humans. Lighting has been recognized to have an effect on clinician wellness and performance as well as the occurence of medical errors. In a pilot study, Octavio L. Perez, Ph.D, WELL Accredited Professional and Adjunct Researcher at the Department of Population Health Science and Policy, and his team of scientists and physicians, Christopher Strother, Richard Vincent, Barbara Rabin and Harold S. Kaplan, from the Mount Sinai Hospital, New York, systematically investigated if and how a radically new lighting concept could improve wellness and performance in an emergency department. Read more »

Health + Environment | Outdoor Applications | Resources | Tech-Talks Bregenz | Mar 25, 2019

Tech-Talks BREGENZ - Dr. Maja Grubisic, Researcher, Free University Berlin & Leibniz-Institute

Awareness of the ecological impact of technologies is becoming more important since climate change due to industrialization cannot be denied. LED lighting is one of the technologies that is deemed as a contributor in helping to reduce the impact caused by wasted energy. Unfortunately, light pollution, due to inefficient energy usage, is not the only problem. Besides the more recognized pollution from pesticides and chemical pollutants, light pollution also disturbs ecology and wildlife. Dr. Grubisic, Researcher at the Free University Berlin & Leibniz-Institute, has been working on this problem for more than five years now. She has written an article, also in this issue, concerning this. At the LED professional Symposium she was also good enough to grant this interview, providing some background information, explaining why light pollution is such an issue in biology and why this topic should be of concern to all of us. Read more »

Resources | Commentary | Mar 25, 2019

An Industry at a Crossroads

Commentary from LpR 70: We often hear grumbles about the lighting industry suffering under low margins and high costs. Primarily, this is true for most traditional luminaire manufacturers but not as much for innovative controls and driver manufacturers, and even less so for innovative newcomers who understand the semiconductor business that has taken over a share of the luminaire manufacturers' revenue. Read more »

Resources | LpR Article | Technologies | Thermal Management | Feb 01, 2019

Materials, Manufacturing and Technologies for Designing Passive Cooling Devices

Until recently, incandescent bulbs and fluorescent lights were the dominant light sources. Today it’s the energy efficient, durable and, in the meantime, cost effective, LED. But to achieve these attributes appropriate cooling is still necessary and due to progress over the last few years the need for active cooling solutions is limited to a few high power applications as long as the material and technology is carefully chosen. John Broadbent, Managing Director at Columbia-Staver Ltd., describes the different technologies and materials and gives practical advice on how to find the right solution for an application. Read more »

Resources | LpR Article | Engineering | Optics | Jan 31, 2019

Additive Optics Design and Fabrication for Smart Lighting Systems and Tailored Project Solutions

Since its initial invention back in 2009, printed optics has come a long way in the lighting industry. Additive optics fabrication is a future proof methodology of rapid prototyping custom LED optics by means of digital manufacturing technologies. Marco de Visser, Luximprint’s Director of Marketing & Sales, breaks down the technology and explains how its features add value to the design and manufacture of smart lighting applications. From one of Luximprint’s preferred optical design partners Physionary, Ramon van der Hilst, Founder and Business Development Manager, and Suresh Christopher, inventor of the state-of-the-art “target-to-source” optics design software, explain the benefits of an optimized design process. Read more »

Qualified Bluetooth Mesh – Making Lighting Controls Future-Proof

LpR 69 Article, page 88: At Lightfair USA, Siegfried Luger met with Patrick Durand, Worldwide Technical Director at Future Lighting Solutions. One of Mr. Durand’s striking statements was: “Basically, what we need is to future-proof lighting control.” This was the first time that this important aspect was so clearly addressed by a representative of the industry. This led us to asking Mr. Durand to provide LED professional with a technical article to clarify the current situation, explain the technical background that led him to making that statement and to give an idea of which requirements a controls solution must fulfill to be truly future-proof. 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 »

Rethinking the Photometric Data File Format

With increasing computing power, engineering disciplines cannot be imagined without simulations anymore. In lighting, photometric data and electronic processing of this data has become one of the most important tools for luminaire design and lighting design. This data is today provided in IES LM-63 format, a format that meanwhile has come to its limits. P. Eng. (Ret) Ian Ashdown, Senior Scientist at SunTracker Technologies Ltd., explains why the time for a change to a new standard has come and discusses the newly proposed standard and its properties in detail: ANSI/IES TM-33 respectively UNI 1603054. Read more »

Optical Designs to Improve LED Lighting Efficiency of Medical Endoscopes

Lighting efficiency for endoscopic instruments has been deemed very poor, at only about 20%. While laboratory tests demonstrate that fiber optics bending is not problematic, optical simulations clearly show that lighting efficiency is strongly limited by the Étendue. Because of strong geometrical constraints in the light coupling area of an endoscope system, only a radical new optical design can provide significant improvement. Alexander Gaertner and Paola Belloni from the Faculty of Mechanical and Medical Engineering and the Steinbeis Transferzentrum Lichttechnik und Beleuchtungsoptik at the University Furtwangen discuss these issues and propose possible approaches. Read more »

Resources | LpR Article | Research | Micro-Optics | Jan 15, 2019

Smart Design of Freeform Micro-Optical Elements for Thin Direct-Lit Luminaires

LpR 69 Article, page 64: Direct-lit LED luminaires consist of LED arrays. In order to achieve homogenous light distribution a diffuser sheet is placed at a certain height above the LED array. Usually the distance between the LEDs and the diffuser has to be greater than the distance between the LEDs on the array. To overcome this limitation, additional optical elements like freeform lenses are necessary. Christian Sommer, scientist at the Institute of Surface Technologies and Photonics of the Joanneum Research Forschungsges.m.b.H and his colleagues, Claude Leiner, Ladislav Kuna, Paul Hartmann and Franz P. Wenzl propose a smart design concept for an extremely flat, direct-lit lighting system, making use of mask-less laser direct write lithography. Read more »

Evaluating Performance of LED-Based Luminaires

LpR 69 Article, page 48: The wide spread of performance data supplied by manufacturers make it difficult for the professional user to reach an “apple-to-apple” comparison, especially if the data is not based on standardized metrics. This is however critical for the preparation of lighting projects or tender specifications. Experts from LightingEurope have therefore developed a guidance document which recommends a fixed set of performance data for LED based luminaires, with particular emphasis to the useful life and the data which is necessary for lighting application design. Read more »