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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 »

Scientific Study Demonstrates Positive Effects of Daylight LED on Visual Comfort, Melatonin, Mood, Waking Performance, and Sleep

There has been an increase in research activity on the relationship between light and human bio-function, including a recent scientific study focusing on the effects of light spectrum on sleep quality, visual comfort, well-being and daytime alertness conducted by Prof. Christian Cajochen and his team at the University of Basel in Switzerland, entitled: "Effect of Daylight LED on Visual Comfort, Melatonin, Mood, Waking Performance, and Sleep." Read more »

Technologies | LEDs | Monolythic RGB LEDs | Color-Tuning | May 02, 2019

Controlling Current, Duty Cycle and Pulses Allows Color Tuning in Monolithic GaN LEDs

A new technique - the result of an international collaboration of scientists from Lehigh University, West Chester University, Osaka University and the University of Amsterdam - could pave the way for monolithic integration for simple color tuning of a light bulb, according to Volkmar Dierolf, Distinguished Professor and Chair of Lehigh's Department of Physics who worked on the project. Read more »

Technologies | Thermal Management | Material Science | Polymers | Apr 30, 2019

MIT Researchers Developed New Heat Conducting Polymer Films

Polymers are usually the go-to material for thermal insulation. Think of a silicone oven mitt, or a Styrofoam coffee cup, both manufactured from polymer materials that are excellent at trapping heat. Now MIT engineers have flipped the picture of the standard polymer insulator, by fabricating thin polymer films that conduct heat — an ability normally associated with metals. In experiments, they found the films, which are thinner than plastic wrap, conduct heat better than many metals, including steel and ceramic. Read more »

Technologies | Light Conversion | Phosphors | White LEDs | Apr 24, 2019

Energy-Saving New Red LED Phosphor Developed at University of Innsbruck

The human eye is particularly sensitive to green, but less sensitive to blue and red. Chemists led by Hubert Huppertz have now developed a new red phosphor whose light is well perceived by the eye. This increases the light yield of white LEDs by around one sixth, which can significantly improve the energy efficiency of lighting systems. Read more »

TU Vienna - New Method to Generate Light from Exotic Particle States

A new type of light-emitting diode has been developed at TU Wien. Light is produced from the radiative decay of exciton complexes in layers of just a few atoms thickness. Read more »

GlacialLight Announces New Natural Sunlight of GL-FL35-NL Architectural Floodlighting Series

GlacialLight, the LED lighting division of GlacialTech Inc., announces the natural sunlight GL-FL35-NL Architectural Floodlighting series. The new lighting fixtures use the SEOUL SunLike CoB to light up objects in their natural colors. The CRI is 97, as well as the CQS (Color Quality Scale) is up to 98. The color fidelity index (TM-30-15 Rf) and color gamut score (TM-30-15 Rg) are close to natural light. 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 »

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 »

3D Bio-Optical Models Reveals How the Human Body Uses the Entire Solar Spectrum

History teaches that global changes to the public's environment mandate a higher level of scrutiny to ensure that we first do no harm. In "Melatonin and the Optics of the Human Body" published in the journal Melatonin Research, Zimmerman and Reiter combine optical ray tracing from lighting and ESR data from the medical industry to model for the first time the 3D free radical distributions generate by lighting sources in the human body. Read more »

An Old Story Re-Edited? - Firefly-Inspired Surfaces Improve LED Efficiency

A new type of light-emitting diode lightbulb could one day light homes and reduce power bills, according to Penn State researchers who suggest that LEDs made with firefly-mimicking structures could improve efficiency. 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 »

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 »

The Possible Future of Lighting - Paint-On Semiconductors from Ornate Quantum Physics

LED lights and monitors, and quality solar panels were born of a revolution in semiconductors that efficiently convert energy to light or vice versa. Now, next-generation semiconducting materials are on the horizon, and in a new study, researchers have uncovered eccentric physics behind their potential to transform lighting technology and photovoltaics yet again. Read more »

Resources | Research | Environment | Street Lighting | Jan 22, 2019

Pollinators: Switch Street Lights off at Midnight to Help Moths and Nocturnal Wildlife

Conservation is often a conflict between the demands of development and a desire to do what is best for the environment. It’s rare that we get the chance to report a decision which was taken for the good of people that has also panned out well for nature’s ecosystems. However, that is just what our new research paper found. 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 »

Colloidal Quantum Dots Make LEDs Shine Bright in the Infrared

ICFO researchers report on the development of a colloidal quantum-dot light emitting diode with unprecedented quantum and power conversion efficiencies in the infrared range. The ideal optoelectronic semiconductor material should be a strong light emitter i.e. should emit light very efficiently upon optical excitation as well as be an efficient charge conductor to allow for electrical injection in devices. These two conditions when met can lead to highly efficient light emitting diodes as well as to solar cells with the possibility to approach the Shockley-Queisser limit. Until now the materials that have come close to meeting these conditions have been based on epitaxially-grown costly III-V semiconductors that cannot be monolithically integrated to CMOS electronics. Read more »

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 »

Researchers Push Perovskite LEDs' Efficiency To Rivaling Best OLEDs

Compared to OLEDs, which are widely used in high-end consumer electronics, the perovskite-based LEDs, developed by researchers at the University of Cambridge, can be made at much lower costs, and can be tuned to emit light across the visible and near-infrared spectra with high colour purity. Now, researchers have set a new efficiency record for LEDs based on perovskite semiconductors, rivalling that of the best Organic LEDs (OLEDs). Read more »

Researchers from the University of Surrey Find that Blue Light Can Reduce Blood Pressure

Exposure to blue light decreases blood pressure, reducing the risk of developing cardiovascular disease, a new study from the University of Surrey and Heinrich Heine University Duesseldorf in collaboration with Philips reports. Read more »

New Algorithm Can More Quickly Predict Phosphor Materials for LEDs

Jakoah Brgoch, assistant professor of chemistry at the University of Houston, and members of his lab published a paper on Oct. 22 in Nature Communications describing how machine learning speeds discovery of new materials. By scanning a huge number of compounds for their key attributes they were looking for a new light conversion material that could be used in white LEDs. Read more »

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 »

Research Reports | Smart Lighting + IoT | Resources | LpR Article | Oct 19, 2018

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 »

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 »

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 »

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