LED professional Review (LpR) - Articles

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

Semi-Empirical Characterization of Freeform Microlens Arrays

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 »

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

Technologies for Shared Office Space

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 | LpR Article | Light Generation | Human Centric Lighting | Health & Environment | Aug 01, 2019

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

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 »

Resources | LpR Article | Research | SciPiL | Medical | Jul 29, 2019

Flex LED Based Smart Light System for Healing of Chronic Wounds

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 »

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

Voice Controlled Lighting that Protects Privacy and Data

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 | LpR Article | Health & Environment | Health | Human Centric Lighting | May 27, 2019

Healthy Light - LED Technology for Health and Care Applications

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 »

Resources | LpR Article | Research | Health | Medical | Human Centric Lighting | May 20, 2019

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

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 »

Resources | LpR Article | Health & Environment | Wellbeing | Human Centric Lighting | May 07, 2019

Melanopic Green - The Other Side of Blue

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 »

Resources | LpR Article | Horticulture | Applications | Apr 17, 2019

Enriching Horticultural Lighting for Faster Growth and Better Crops

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 »

Resources | LpR Article | Special Topics | DC-Grids | Applications | Apr 15, 2019

48 VDC Integrated Drivers Offer New Options

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 »

Resources | LpR Article | Technologies | Driver Modules | NFC | Apr 12, 2019

Standardized Programming of Lighting Components Using NFC Technology

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 »

Resources | LpR Article | Technologies | Controls | Wireless | Bluetooth | Apr 10, 2019

Bluetooth Mesh Protocol as Applied to Lighting

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 | Apr 08, 2019

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

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 | Apr 03, 2019

Hazard or Hope? LEDs and Wildlife

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 »

Resources | LpR Article | Research | Health | Medical | Human Centric Lighting | Apr 01, 2019

Lighting and Emergency Dept. Clinician Wellness and Performance Improvement

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 »

Resources | LpR Article | Research Reports | OpenAIS | Smart Lighting & IoT | Mar 29, 2019

User Evaluation of the OpenAIS Pilot Installation

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 | Technologies | Thermal Management | Feb 18, 2019

Materials, Manufacturing and Technologies for Designing Passive Cooling Devices

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 | Feb 11, 2019

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

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 »

Resources | LpR Article | Technologies | Smart Lighting & IoT | Bluetooth | Jan 31, 2019

Qualified Bluetooth Mesh – Making Lighting Controls Future-Proof

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 »

Resources | LpR Article | Applications | Artificial Intelligence | Controls | Jan 31, 2019

Interactive Lighting Control is Opening New Doors for LED Applications

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 »

Resources | LpR Article | Engineering | Lighting Simulation | Standardization | Jan 15, 2019

Rethinking the Photometric Data File Format

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 »

Resources | LpR Article | Research | SciPiL | Optics | Jan 15, 2019

Optical Designs to Improve LED Lighting Efficiency of Medical Endoscopes

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

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 »

Resources | LpR Article | Organization News | LightingEurope | Applications | Dec 17, 2018

Evaluating Performance of LED-Based Luminaires

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 »

Resources | LpR Article | Standardization & Regulation | Zhaga | Connected Lighting | Smart Lighting & IoT | Dec 14, 2018

Zhaga Enables Mechanical IoT-Upgradability for Outdoor LED Lighting Fixtures

Zhaga Enables Mechanical IoT-Upgradability for Outdoor LED Lighting Fixtures LpR 69 Article, page 42: The Zhaga Consortium is a global association of lighting companies that is standardizing LED luminaire components interfaces. The latest specification from Book 18 defines a standardized interface between outdoor LED luminaires and modules for sensing and communication. Dee Denteneer, Zhaga Secretary General, explains how the New Book 18 helps bring the Internet of Things to the outdoor lighting market via smart, upgradeable, future-proof fixtures. Read more »

Resources | LpR Article | Research News | CIE | Applications | Dec 12, 2018

How to Use the Technologies for Adaptive Lighting

How to Use the Technologies for Adaptive Lighting The technologies to provide adaptive lighting are already in the marketplace and are accepted by some jurisdictions. Nonetheless, we have an inadequate understanding of how best to use these technologies, meaning that installations might not serve users well, and in the worst case, might lead to harm. Lighting researchers can generate the knowledge needed to support the best application of adaptive lighting technologies. The International Commission on Illumination (CIE) understands the importance and urgency to deal with problems of adaptive, dynamic and intelligent lighting in all application fields. Hence, this topic is a highlight of CIE’s research strategy. Read more »

Resources | LpR Article | Technologies | Horticulture | UV | Dec 01, 2018

UV LED Technology for Emerging Applications in Agriculture

UV LED Technology for Emerging Applications in Agriculture The Ultraviolet (UV) LED market has expanded five-fold in the past decade and is projected to grow to over $1 billion by 2025. A key trend expected to influence the market is the ability to expand into new applications, including agriculture. UV light, at proper frequency and dose, can increase the production of active substances in medicinal and traditional plants and it can also help maintain a healthy growing environment. But to fully take advantage of UV LEDs, some major re-design considerations are required. Terrance Berland, CEO of the Violet Defense Group, the parent company of Violet Gro, will explain which considerations these are; for instance, why it is crucial to incorporate the appropriate lens material. Read more »

Resources | LpR Article | Research Reports | Smart Lighting & IoT | Nov 26, 2018

Challenges of the Integration of Lighting Systems and Components in IoT

Challenges of the Integration of Lighting Systems and Components in IoT LpR 68 Article, page 50: Following the rapid penetration of LEDs, lighting is now becoming integrated into the Internet of Things. Over the past three years a consortium of leading European companies worked on the OpenAIS project, which was partly funded by the EU within the Horizon 2020 program, and now showing the results working at a full size demonstrator. In this follow up article to the introduction article of LpR 67, Ben Pronk, System Architect at Signify, and Stefan Verbrugh, Project Manager at Signify and Work Package leader in OpenAIS give deeper insight into the project. They explain the lighting specific challenges, describe the generic challenges for IP controlled lighting and present the approach to these challenges. They conclude by summarizing the findings from the pilot. Read more »

Resources | LpR Article | Research | Light Generation | Laser Technology | Nov 19, 2018

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

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 »

Resources | LpR Article | Research | Manufacturing | LED Modules | Nov 05, 2018

A Study on Aerosol Jet Printing in LED Module Manufacturing

A Study on Aerosol Jet Printing in LED Module Manufacturing LpR 68 Article, page 38: LED module manufacturing technologies have certainly improved over the last few years but the requirements have also increased. More components are packed on today’s modules causing additional thermal stress, and, at the same time, the demand for lower cost challenges module manufacturers. So the (re-) search for new materials and new manufacturing processes and manufacturing technologies is still on. Paul Hartmann, Director of the Institute of Surface Technologies and Photonics at the Joanneum Research Forschungsgesellschaft m.b.H., and his team, Andreas Rudorfer, Martin Tscherner, Christian Palfinger, Frank Reil, Franz P. Wenzl with Ioannis E. Seferis, Eugeniusz Zych from the Faculty of Chemistry of the University of Wroclaw investigated the opportunities of aerosol jet printing and proved the applicability for alternative ways of phosphor deposition and integration and to replace wire bonding of dies. Read more »

FEATURED

Nationstar Overall Layout in UV LED Market

Nationstar Overall Layout in UV LED Market In August 2018, Nationstar set up the Non-visual Light Source Business Division, focusing on IR LED, UV LED, animal and plant lighting. Nationstar has been fully laid out on UVA/UVB/UVC. Since 2016, Nationstar has launched near-ultraviolet LED, deep-ultraviolet LED and modules, with wide wavelength ... 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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