Articles & Interviews

LpR Article | Technologies | Jul 01, 2016

How Silicones are Evolving to Meet the Growing Needs of the LED Lighting Industry by Dow Corning

There are different materials for optics in lighting applications. The lighting application engineers François de Buyl, Martijn Beukema and Kevin van Tiggelen from Dow Corning are convinced that silicone’s unique qualities help to expand options in the design and molding of LED packaging components, as well as components for lamp and luminaire applications. Read more »

LpR Article | Sep 05, 2016

How to Design with LEDs: Concurrent Engineering Yields Fully Optimized Lighting Systems

LEDs are often viewed as a replacement for other light sources. The right starting point for designing an appropriate replacement is crucial to the result. Brian S. Jasenak, Optical and Process Engineer at Kopp Glass, describes a concurrent engineering approach that optimizes the optics and other system components, and may help to reduce the number of LEDs needed as well as the overall cost of the LED lighting fixture. 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 »

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 »

LpR Article | Jul 04, 2016

Human-Centric Lighting: Sensor Technology for Full- Spectrum Lighting Solutions by ams

While not necessarily common knowledge, research is rapidly validating the common-sense understanding that human beings are “tuned” to the natural lighting cycles of the sun, and can be equally “de-tuned”, to the detriment of both health and productivity, by artificial light sources that operate contrary to these natural flows. Sajol Ghoshal, Director of Sensor Driven Lighting at the Opto Sensor and Lighting BU at ams, discusses the available approaches for full-spectrum solutions, and potential humancentric benefits, of fully integrated intelligent ambient/color light sensor and driver technology. Read more »

LpR Article | Research | May 17, 2016

Human-Focused Outdoor Illumination: Trade-Off Between Pleasing Color and Circadian Action, by the Vilnius University

A smart RGBA solid-state light engine with tunable correlated color temperature (CCT) and high-fidelity color rendition was applied for the validation of the Kruithof hypothesis in several outdoor environments. Subjects were asked to find the most “pleasing” illumination conditions by performing a CCT adjustment. Maintaining constant illuminance, the mean selected CCT was found to increase from about 3000±200 K at 5 lx to about 3500±250 K at 50 lx almost independently of the content of the viewed scene. Dr. Pranciškus Vitta, Head of Lighting and Electronics System Lab at the Vilnius University shows that this increase is statistically significant and provides qualitative validation of the Kruithof hypothesis in outdoor environments, but with the intervals of CCT for “pleasing” illumination, it is substantially broader and shifted to higher values. Read more »

Resources | LpR Article | Event-Reports | Trends | May 30, 2016

Light + Building Post Show Report: The Six Most Noteworthy Observations by LED professional

In the weeks and months before the show it was obvious that the major topics were going to be IoT and connectivity. There are many reasons for this. One is that LED lighting has become established but the big deals for smart lighting and human centric lighting are missing. IoT seems to be the way to improve communication and enable both smart lighting and HCL. Arno Grabher-Meyer from LED professional gives a summary of his impressions of the fair in regards to these topics, and beyond. Read more »

LpR Article | Research | Jan 26, 2017

Lifetime Calculation of White HP-LEDs from 16,000 Hours Aging Data

Accurate models are a relevant tool for correctly calculating the so-called useful lifetime predictions of LED lighting products. Until recently, only the efficiency decay and related reduced lumen output was taken into account. Max Wagner, Research Assistant, TU Darmstadt, and his co-authors, Alexander Herzog, Hristo Ganev, and Prof. Tran Quoc Khanh asked themselves if there are other lifetime limiting factors that can be modelled and predicted. Their findings showed that color shift might be more critical and in the following, propose a method to simulate and predict this behavior. Read more »

Event Post Show Report | LpR Article | Nov 28, 2016

LpS Event: A Perfect Platform for New Ideas and Innovations

Like in any “Light + Building year”, there is always the question of which, if any, other shows one should attend in Europe. The visitors to the LpS 2016 knew right from the start that they had made the right decision with Bregenz. As always, the show attracted attendees, exhibitors and visitors from all over the world. Arno Grabher-Meyer, Editor-in-Chief at LED professional summarizes the highlights and shows how the newly introduced program points were received. Read more »

Leading Article | LpR Article

2015 Year of (LED) Light

The advent of artificial lighting has revolutionized society. 2015, in particular, will go a long way in establishing solid-state light-based technologies as a vital area of innovation for the 21st century. Dr. Amrita Prasad from LED professional gives an overview of the technical evolution of (LED) lighting and how this may have triggered UNESCO’s decision to make 2015 the Year of Light. Read more »

LpR Article | May 11, 2016

230 VAC Driven LED Modules with Strongly Reduced Flicker, by euroLighting

One of the continuing trends in LED lighting is toward AC driven LED modules. Big progress has been made regarding dimmability and reduction of flicker. However, there are still differences in the various concepts that lead to very different results. Wolfgang Endrich, founder and managing director of euroLighting presents a recently improved new concept to significantly reduce flicker. Read more »

LpR Article

3-Pad LED Flip Chip COB

Wafer level packaging and flip chip design are the most recent trends in LED manufacturing and packaging. These LED types are perfectly suited for producing COB modules. This combination already promises better thermal performance than standard SMD package based products. However, there is still room for improvements. Pao Chen, Director of Research and Development at Flip Chip Opto shows how a 3-pad flip chip LED further reduces thermal resistance, allows higher power and can help to reduce costs. Read more »

LpR Article | Technologies | May 19, 2016

3-Pad LED Flip Chip COB by Flip Chip Opto

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 »

LpR Article | Research | Jun 08, 2016

A Graphene-Based, Spectrally Tunable, Flexible Field-Effect Light-Emitting Device by the Tsinghua University and the Tsinghua National Laboratory for Information Science and Technology

The continuous tuning of the emission spectrum of a single light-emitting diode (LED) by an external electrical bias is of great technological significance as a crucial property in high-quality displays and may be used in high quality lighting applications, yet this capability has not been demonstrated in existing LEDs. Graphene, a tunable optical platform, is a promising medium to achieve this goal. Xiaomu Wang, He Tian, Mohammad Ali Mohammad, Cheng Li, Can Wu, Yi Yang, and Tian-Ling Ren from the Institute of Microelectronics at the Tsinghua University in Beijing and the Tsinghua National Laboratory for Information Science and Technology (TNList) demonstrate a bright spectrally tunable electroluminescence from blue (~450 nm) to red (~750 nm) at the graphene oxide/reduced-graphene oxide interface. Read more »

A Lighting Designers Relativity of Light Performance

The LED will always be the superstar of light sources. Their precise and clear lighting possibilities have been targeted by lighting planners and architects for the past ten years. The coming years will see the performance of the LED getting progressively closer to the spectrum of daylight and that will, in turn, generate biologically effective LEDs that are even higher in contrast and promise a new kind of feel-good light. Read more »

A Near Infrared Enhanced LED Lighting Approach

With the evolution of LED lighting, one topic has come more and more in the focus of the lighting industry: Human Centric Lighting (HCL). While HCL is not clearly defined, a common understanding is that this is light and lighting that supports health and the well-being of humans. Some new proposals are going beyond the approach of providing just visible light in adequate quality, but also to providing invisible radiation, UV and/or NIR that support health and well-being. Some research and the evolution of humans show clear evidence for positive effects of this kind of illumination. Scott Zimmerman, CEO at Silas, presents a new approach that adds NIR radiation to LED illumination. He explains the background of this idea, how it also improves the quality of visible light and discusses the health benefits. 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 »

Technologies | LpR Article

A New Approach to the Design of Driverless AC LED Light Engines

Driverless AC LED light engines have now become a commonplace item of commerce in the lighting industry. Nearly all of them use high voltage integrated circuit switching chips to intelligently change the number of LEDs in a string during a power line cycle so that the voltage of the LED string matches the instantaneous power line voltage. However, customers are demanding higher efficiency, lower cost, and especially a reduction in the flicker content of the emitted light. Peter W. Shackle, president of the consulting company, Photalume, describes some new circuits for AC LED light engines [1] that provide a non-dimming solution with reduced cost, increased efficiency and better light quality as perceived by the human eye. 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 »

A New Technology Is Changing the Tunable White Solutions

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

Research | LpR Article

A Self-Compensation Approach for Maintaining the Chromaticity Coordinates of Phosphor Converted LEDs Upon Temperature Variations

Solid-state light sources for general illumination applications are currently becoming more and more popular. Maintaining chromaticity coordinates over temperature is a challenge. Wolfgang Nemitz, Franz P. Wenzl, Susanne Schweitzer, Christian Sommer, Paul Hartmann from the Institute for Surface Technologies and Photonics at Joanneum Research, and Paul Fulmek and Johann Nicolics from the Institute of Sensor & Actuator Systems of the Vienna University of Technology investigated this issue and propose a promising new solution. Read more »

A Standardized Open Platform Is Key to the Future of Smart Lighting System Design

The LED industry’s pace of evolution is more prevalent now than it has ever been. The shift from traditional standalone LED bulb lighting to fully connected digital LED systems is upon us and is transforming the industry for the better. For years, LED manufacturers have focused on driving cost down rather than focusing on improving quality, but with the advent of connected lighting, smart lighting and human-centric lighting, the focus has shifted back onto quality. Dr. Kyeongik Min, Principal Engineer in the LED business team at Samsung Electronics, explores how the LED industry can accelerate the transition from standalone lighting to fully connected lighting through a deeper understanding of current market trends. 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 »

Resources | LpR Article | Environment | Oct 31, 2017

A World of LED Lights - The Cost of Waiting

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

Abrasion in Transparent Lens Materials for Exterior Aircraft Lighting

Research, Engineering, and Quality Assurance at Kopp Glass, reports how Taber abrasion and high-velocity particulate testing was performed on three different jet aircraft lens materials, including: heat strengthened borosilicate glass (Kopp 9000), hard-coated polycarbonate, and aviation grade acrylic (Makrolon AR and Plexiglas II UVA). Read more »

LpR Article | Jul 04, 2016

Additive Manufacture of Optics Goes Digital by LUXeXceL B.V.

With a new technology for additive manufacturing, optics fabrication has gone digital, making more product innovation and variety affordable by eliminating the expense of molds and tooling, enabling just-in-time manufacturing and bringing a new freedom for optics and lighting designers. Marco de Visser, Business Development Manager at LUXeXceL B.V. gives an update on this technology and its new opportunities. 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 »

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 »

LpR Article | Apr 21, 2016

Advanced Bluetooth 4.0+ Based Smart Lighting Technology

Smart lighting and lighting controls are not restricted by hardware or traditional lighting control protocols anymore. Today, system modifications and firmware updates can all be done over-the-air. Wireless technologies enable lighting controls in places where it was not an option before. Besides Bluetooth, Zigbee and WiFi there are proprietary technologies in use. Saara Guastella M.Sc. in Lighting Engineering and Lighting Controls, is Product Marketing Manager at Casambi. In the following article she introduces Casambi’s technology based on Bluetooth Low Energy, and describes, explains and compares it with other established communication technologies for smart lighting. Read more »