LED professional Review (LpR) - Articles

LpR Article | Jul 05, 2016

Energy Efficiency and Thermal Simulations of a Retrofit LED Light Bulb by the University of Turku

Energy Efficiency and Thermal Simulations of a Retrofit LED Light Bulb by the University of Turku Mika Maaspuro and Aulis Tuominen from the University of Turku investigated the energy efficiency of a LED driver mounted inside a retrofit light. The heat generation of the LEDs and the driver of the light bulb have been simulated and measured. A thermal model for the light bulb has been created and simulated using a Finite-Element-Method (FEM) software. Parameters of the model have been adjusted to match the temperature measurements which have been done with IR-camera and thermocouples. Read more »

LpR Article | Jul 05, 2016

Energy Efficiency and Thermal Simulations of a Retrofit LED Light Bulb by the University of Turku

Energy Efficiency and Thermal Simulations of a Retrofit LED Light Bulb by the University of Turku Mika Maaspuro and Aulis Tuominen from the University of Turku investigated the energy efficiency of a LED driver mounted inside a retrofit light. The heat generation of the LEDs and the driver of the light bulb have been simulated and measured. A thermal model for the light bulb has been created and simulated using a Finite-Element-Method (FEM) software. Parameters of the model have been adjusted to match the temperature measurements which have been done with IR-camera and thermocouples. Read more »

LpR Article | Jul 05, 2016

Sensors and Feedback Control of Multi-Color LED Systems by MAZeT GmbH

Sensors and Feedback Control of Multi-Color LED Systems by MAZeT GmbH To obtain stable and consistent lighting conditions within the black body range with LED systems, especially RGBx systems is a challenging task. Feedback controlled systems are expensive, but the best solution. Here, the question of which type of sensor accomodates the given application best, arises. Thomas Nimz, Fredrik Hailer and Kevin Jensen from MAZeT GmbH discuss different options based on their scientific studies on LED systems with four or more different LEDs considering secondary conditions like color rendering index. Read more »

LpR Article | Jul 05, 2016

Mesopic Photometry - An Accurate System of Road Lighting Evaluation by Surya Roshni Ltd.

Mesopic Photometry - An Accurate System of Road Lighting Evaluation by Surya Roshni Ltd. For a long time, photopic vision was the basis for all light measurement tasks, but today this approach is challenged. According to several research results, it seems that mesopic vision should be used as a basis to evaluate street lighting applications or other low level lighting applications. Prija Jain from the Executive Design and Development (Photometry & Optics) department of Surya Roshni Ltd. in India gives us an overview on the recent status of the discussion, explains it and shows the resulting consequences. Read more »

LpR Article | Jul 05, 2016

Practical Results of a Gas Station Refurbishment with LED Luminaires by the Electromagnetica SA Semiconductor Lighting Centre

Practical Results of a Gas Station Refurbishment with LED Luminaires by the Electromagnetica SA Semiconductor Lighting Centre Perfect lighting at a gas station is very important for competitiveness. But a conventional lighting system is also a costly and energy demanding installation with high maintenance costs. Stelian Matei from the Electromagnetica SA Semiconductor Lighting Centre shows how a well-planned upgrade of conventional lighting to LED lighting lowers energy consumption and maintenance and, therefore, costs. Read more »

LpR Article | Jul 05, 2016

Practical Results of a Gas Station Refurbishment with LED Luminaires by the Electromagnetica SA Semiconductor Lighting Centre

Practical Results of a Gas Station Refurbishment with LED Luminaires by the Electromagnetica SA Semiconductor Lighting Centre Perfect lighting at a gas station is very important for competitiveness. But a conventional lighting system is also a costly and energy demanding installation with high maintenance costs. Stelian Matei from the Electromagnetica SA Semiconductor Lighting Centre shows how a well-planned upgrade of conventional lighting to LED lighting lowers energy consumption and maintenance and, therefore, costs. Read more »

LpR Article | Research | Jul 04, 2016

Flexible OLEDs for Lighting Applications by the Holst Centre

Flexible OLEDs for Lighting Applications by the Holst Centre While OLEDs already have successfully found their way into display applications, the breakthrough in lighting applications is still pending. The reasons are diverse, but cost is one major point. Another reason is the current edge of inorganic LEDs giving reasonable design opportunities in many standard applications. However, there are applications where OLEDs could score, especially the flexible OLEDs. But even these OLEDs need to become cheaper to be applied widely. The Holst Centre and partners aim to develop generic technologies for large area flexible OLEDs which can be processed with roll-to-roll (R2R) technology. Process Engineer Tansim Baig gives an example and an overview of the current status of the development. Read more »

LpR Article | Jul 04, 2016

Lighting & Building Automation Technologies

Lighting & Building Automation Technologies The transition from traditional lighting technology to LED is old news. People in the lighting business no longer talk about the “LED Revolution”. Today’s revolution, perhaps spurred on by LED technology, is in building automation and lighting controls. Lighting experts know that while LED products have the potential to achieve terawatts of power savings worldwide over the next decade, even larger power savings might be achieved through effective lighting control and building automation systems. Greg Galluccio, Director at Leviton Manufacturing discusses lighting load-shedding strategies, such as daylight harvesting, occupancy sensing, task management and demand response as well as the trends towards the interaction of lighting control with other building functions. Read more »

LpR Article | Jul 04, 2016

Advanced Passive Thermal Management Solutions for High Power LEDs by Advanced Cooling Technologies (ACT)

Advanced Passive Thermal Management Solutions for High Power LEDs by Advanced Cooling Technologies (ACT) There are two main solutions to improve passive thermal management in LED devices. One is to increase the surface area of a heat sink. This requires additional size, weight and material and offers only marginal improvement. The second solution is to increase the thermal conductivity between the heat source and the sink. The latter is supported by well-established technologies like heat pipes and vapor chambers. Richard Bonner, Manager for Custom Products, and Peter Ritt, Vice President at Advanced Cooling Technologies (ACT) give insight into the latest developments and explain how they work, how they are designed and applied correctly, and discuss their opportunities, advantages and limitations. Read more »

LpR Article | Jul 02, 2016

Using Integrating Spheres Correctly to Measure LEDs

Using Integrating Spheres Correctly to Measure LEDs LEDs have opened up new dimensions of design freedom, allowing architects and designers to give free rein to their creativity. Light-emitting diodes permit manifold design solutions as a light source in illumination products. However, a suitable measuring method for comparing key technical data is required in order to get the best out of the diversity of illumination products available. Mikolaj Przybyla from GL OPTIC, a Just Normlicht GmbH division, explains crucial product requirements and what to take care about when calibrating a measurement system. Read more »

LpR Article | Jul 02, 2016

Reliable Thermal Management of High-Power LEDs by Haeusermann

Reliable Thermal Management of High-Power LEDs by Haeusermann Stefan Hörth believes that FR4 PCBs can easily replace IMS PCBs and even open new fields of LED applications. Haeusermann’s HSMtec Product Manager demonstrates that common FR4 laminates, including special copper filling, will sufficiently withstand the heat of HB LEDs. Read more »

LpR Article | Jul 02, 2016

EMI Problems in TRIAC Dimmable LED Drivers by RECOM Lighting

EMI Problems in TRIAC Dimmable LED Drivers by RECOM Lighting TRIAC dimming adds a dimension to Power Factor (PF) and Total Harmonic Distortion (THD) that is rarely defined by LED driver manufacturers. Bianca Aichinger, Product Marketing Manager at RECOM Lighting, examines the relationship between PF, THD and harmonics and explains why this relationship can change as soon as the LEDs are dimmed, thus causing increased EMI and undesirable visible effects such as LED flashing and flicker. The European standards for EMC and Harmonics are only specified for full load and in the non-dimmed condition. In practice, there are often dimmer/driver/LED load conditions which may meet the regulations when undimmed, but fail significantly if dimming is used. Read more »

LpR Article | Jul 02, 2016

An Economical Omnidirectional A19 LED Light Bulb by the Industrial Technology Research Institute

An Economical Omnidirectional A19 LED Light Bulb by the Industrial Technology Research Institute Since 2009, when the Japanese government was vigorously promoting LED bulbs in end-market applications, they have become mainstream commodities in the LED lighting market. Chen-Peng Hsu, project manager of Electronics and Optoelectronics Research Laboratories at Industrial Technology Research Institute (ITRI), introduces the R&D 100 award-winning invention of an omnidirectional A19 LED light bulb that is light weight and economical. Read more »

LpR Article | Jul 01, 2016

The Influence of LED Emission Characteristics on the Efficiency of Lighting Systems by Osram Opto Semiconductor

The Influence of LED Emission Characteristics on the Efficiency of Lighting Systems by Osram Opto Semiconductor In general lighting, efficiency is the main focus. Under specific operation conditions, the main issue appears to be luminous flux. Dr. Roland Schulz, application engineer in the Solid State Lighting division at Osram Opto Semiconductor, takes a deeper look at the influence of LED radiation characteristics. Read more »

LpR Article | Jul 01, 2016

The Influence of LED Emission Characteristics on the Efficiency of Lighting Systems by Osram Opto Semiconductor

The Influence of LED Emission Characteristics on the Efficiency of Lighting Systems by Osram Opto Semiconductor In general lighting, efficiency is the main focus. Under specific operation conditions, the main issue appears to be luminous flux. Dr. Roland Schulz, application engineer in the Solid State Lighting division at Osram Opto Semiconductor, takes a deeper look at the influence of LED radiation characteristics. Read more »

LpR Article | Technologies | Jul 01, 2016

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

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 | Jul 01, 2016

Labeling and Certification Testing Issues by UL

Labeling and Certification Testing Issues by UL Arno Grabher-Meyer from LED professional summarizes several issues regarding certification and certification processes which were discussed with David Edwards, an expert in testing and compliance engineering for consumer products at UL. Read more »

LpR Article | Jul 01, 2016

Choosing the Appropriate Heatsink for an Application by Fischer Elektronik

Choosing the Appropriate Heatsink for an Application by Fischer Elektronik Next to vibrations and moisture, temperature-related stress on electronic semiconductor elements is the most common cause of failure for electronic components and devices. Effective thermal management is obligatory to ensure durability, reliability and performance. Jürgen Harpain, Manager of Development at Fischer Elektronik explains how different types of heatsinks provide excellent solutions and which one is the appropriate solution for a given application. Read more »

LpR Article | Jul 01, 2016

Thermal Management for LEDs Beyond Thermal Conductivity Values by Electrolube

Thermal Management for LEDs Beyond Thermal Conductivity Values by Electrolube Specifically designed and formulated chemical products are widely used in the electronics industry for a vast array of applications. Jade Bridges, European Technical Support Specialist at Electrolube explains why such products have become an essential factor in ensuring the performance and quality of electronic devices, whether it is during PCB manufacture or for the protection of components or complete devices. Read more »

LpR Article | Jul 01, 2016

Boost-Buck LED Driver Topology for Low Input and Output Ripple for Low EMI by Linear Technology

Boost-Buck LED Driver Topology for Low Input and Output Ripple for Low EMI by Linear Technology Many automotive LED driver circuits require constant-current DC/DC converter topologies that can both step-up and step-down the input-to-output voltage. Out of the commonly used step-up and step-down topologies, those that produce low EMI are the most desirable. Keith Szolusha, applications engineering section leader with Linear Technology, proposes a new boost-buck (boost-then-buck-mode) floating output LED driver to satisfy these requirements. Read more »

LpR Article | Jul 01, 2016

Light Guide Technology for Obtaining a Different Bi-Directional Direct/Indirect Light Emission Pattern

Light Guide Technology for Obtaining a Different Bi-Directional Direct/Indirect Light Emission Pattern Market requirements ask for a solution for use in suspended light fixtures that will allow the light to be distributed upward, for indirect illumination, as well as downward, for direct illumination. However, existing light guide technology typically produces fairly indirect light and relatively uncontrolled distribution. Brett Shriver, Vice President at Global Lighting Technologies, explains a new approach with individual light extraction features used within the light guide in order to control light in multiple directions and provide the required semi-Lambertian distribution in the downward direction with low glare while obtaining a bat-wing type distribution in the upward direction. Read more »

LpR Article | Technologies | Jun 30, 2016

High Color-Rendering, Full-Visible-Spectrum LEDs by Soraa

High Color-Rendering, Full-Visible-Spectrum LEDs by Soraa The first wave of conventional white LEDs primarily focused on lumens per Watt. These LEDs were based on phosphor down-conversion using primary blue “pump” emission. Currently LEDs are catching up in regards to light quality using different approaches. Aurelien David, Senior Principal Scientist and Mike Krames, Chief Technology Officer at Soraa explain their technology approach of violet-pumped, full-visible-spectrum LEDs, and the interrelated challenges and advantages. Read more »

LpR Article | Jun 29, 2016

Predictive Simulation to Virtually Test Product Design and Reduce Time to Market by Trinseo

Predictive Simulation to Virtually Test Product Design and Reduce Time to Market by Trinseo With technical progress and new regulations, shorter product cycles are a continuous challenge for OEMs. Modelling is one measure to cut time to market efficiently without compromising product quality. Trinseo Technical Service & Development specialists Kersten Terry and Berend Hoek explain the process of computer-based simulation, specifically applied to injection molded plastic parts. Through case studies, they showcase how Trinseo’s Application Engineering Development resource facilitates more effective LED-lighting development relative to part design, tool design and material selection by modelling “real world“ performance. Read more »

LpR Article | Jun 27, 2016

Thermal Transient Testing of LEDs for More Reliable SSL Products by Mentor Graphics

Thermal Transient Testing of LEDs for More Reliable SSL Products by Mentor Graphics An LED device’s reliability, useful operating lifetime and luminous flux are basically determined by the junction temperature; therefore, so is the lifetime and reliability of the final SSL application. Thermal transient testing is now supported by new industrial laboratory testing standards published by JEDEC. Dr. Andras Poppe, Mechanical Analysis Division, MicReD, at Mentor Graphics will explain the corner stones of this standard and discuss application examples. This includes measurement of the RthJC, test-based thermal modeling of the LED package, hot lumens prediction, and monitoring of degradation of the thermal interfaces during life-time test, to name just a few. Read more »

LpR Article | Technologies | Jun 26, 2016

Safety Issues for LED Drivers with PWM Operation Modes by Product Approvals Ltd.

Safety Issues for LED Drivers with PWM Operation Modes by Product Approvals Ltd. In many cases LED drivers manage their output power with PWM controlled switched mode power supply-topologies. The output voltages are filtered and normally DC voltages with low ripple apply at the output connectors of LED drivers. During dimming these circuits can behave very differently and therefore safety issues may arise. Siegfried Luger, CEO at Luger Research e.U. and John Showell, Product Safety Consultant at Product Approvals Ltd. have a closer look at those operation modes and the requirements on voltage limits. Read more »

LpR Article | Jun 25, 2016

The Role of Special Optics in Human Centric Lighting and Architecture by Suleyman Turgut and Luminit LLC

The Role of Special Optics in Human Centric Lighting and Architecture by Suleyman Turgut and Luminit LLC While Human Centric Lighting is relatively new and a topic of some debate, few can argue over the benefits of creating more natural lighting conditions in offices, retail spaces and other architectural settings. Anthony Ang, Optical Engineer, Suleyman Turgut, Director of Sales, and Mary Ann Giorgio, Marketing Communications Specialist at Luminit LLC show how special or “tertiary” optics, such as diffuser and direction film, can play a crucial role in Human Centric Lighting or lighting that takes into account the emotional and biological needs of humans. Read more »

LpR Article | Technologies | Jun 25, 2016

Optimization of SSL LED Devices by Osram Opto Semiconductors

Optimization of SSL LED Devices by Osram Opto Semiconductors There are different levers to improve LED performance. Ralph Bertram, application engineer for SSL products, and Alexander Wilm, key expert in the SSL application engineering department at Osram Opto Semiconductors, have a look into the device itself and explore the principal limitations of the different contributors to device efficacy. They show how to balance driving current and chip size to define the right LED, and explain the impact on performance and system costs of LED packages for the intended lighting task approaches for lighting strategies. Read more »

LpR Article | Jun 24, 2016

Development of a Workflow for Colored Ray Data by TechnoTeam Bildverarbeitung GmbH

Development of a Workflow for Colored Ray Data by TechnoTeam Bildverarbeitung GmbH The importance of white LEDs has risen continuously over the past years. In many cases, disturbing color fringes appear on white LEDs with a blue chip and a yellow phosphor. To avoid this, different distribution of the blue and the yellow light has to be described for simulation. Therefore, colored ray files are necessary. Nicole Stubenrauch, Development Engineer at TechnoTeam Bildverarbeitung GmbH, explains a workflow and method for creating colored ray files. Read more »

LpR Article | Jun 23, 2016

Advanced Optical Plastics Materials for LED Lighting Applications by Styron LLC

Advanced Optical Plastics Materials for LED Lighting Applications by Styron LLC Across a range of lighting solutions, Light Emitting Diodes have emerged as the clear choice for industry and consumers alike. Government regulations and consumer preference for more environmentally-conscious, energy-efficient products have caused manufacturers to develop solutions for the marketplace that offer new levels of energy efficiency, durability and long life. While the technology has evolved, so have the materials that go into the finished product. Claude Van Nuffel, Eric Wu, Peter Jackson and Marta Sans Peña from Styron LLC discuss versatility and one-of-a-kind properties of plastic – especially polycarbonate and polycarbonate blends – and why they have become the “materials of choice”. Read more »

LpR Article | Trends | Jun 23, 2016

Embedded Lighting - Developing New Lighting Applications for Modern Architectural Projects by Philips Lighting

Embedded Lighting - Developing New Lighting Applications for Modern Architectural Projects by Philips Lighting When the era of LED lighting started, everybody talked about the new age of lighting with new opportunities. While many lighting concepts are still pure replacements of the conventional light sources, with the maturation of this technology, more and more new concepts are realized, and the future perspectives are even more exciting. Brad Koerner, Venture Manager - Philips Luminous Patterns at Philips Lighting, shows examples, explains why such new concepts are desirable, and discusses which technologies support the introduction of new lighting applications. Read more »

FEATURED

Epoxy Features Very Low Coefficient of Thermal Expansion

Epoxy Features Very Low Coefficient of Thermal Expansion Master Bond EP30LTE-2 has been developed for joining dissimilar substrates exposed to thermally or mechanically induced stresses. It can be used for sealing, coating and encapsulating, especially for small to medium sized castings where a very low coefficient of thermal expansion (CTE) is required. Read more »

FEATURED

New BJB LED Connector for Linear LED Modules: Book 21 Compliant

New BJB LED Connector for Linear LED Modules: Book 21 Compliant Lampholders were standard in older, traditional lighting systems. Modern LED fixtures that utilize non-replaceable LEDs create several assembly and field-replacement disadvantages. Zhaga Book 21 addresses these shortcomings by standardizing linear 'socketable' LED modules. In accordance with Book ... Read more »

FEATURED

EzyLED™ Now Stocked at Digi-Key

EzyLED™ Now Stocked at Digi-Key American Bright, a global LED lighting solutions manufacturer, announced a series of EzyLED 3030. American Bright's EzyLED™ is a proprietary LED device with a built-in IC. This patented design drastically reduces the need for additional circuitry and other on-board components making it the ideal ... Read more »

FEATURED

Cree Expands Design Possibilities for Architectural Lighting with the Worldwide Proven CLQ6A LED

Cree Expands Design Possibilities for Architectural Lighting with the Worldwide Proven CLQ6A LED These SMD LEDs are packaged in an industry standard PLCC8 package. These high performance 4 color SMT LEDs are designed to work in a wide range of applications. A wide viewing angle and high brightness make these LEDs suitable for signage applications. Read more »

FEATURED

Measuring the Oxygen Content of Blood with LEDs

Measuring the Oxygen Content of Blood with LEDs Pulse oximetry is a non-invasive method for determining haemoglobin (Hb) saturation through oxygen in the blood and heart frequency. It uses the fact that oxygen-rich and oxygen-poor haemoglobin absorb red and infrared light differently. In order to measure the oxygen content reliably, LEDs with ... Read more »

EDITORIAL

The 2019 LpS & TiL Award Winners: Celebrating the Complete Spectrum of Light

The 2019 LpS & TiL Award Winners: Celebrating the Complete Spectrum of Light It is a great pleasure for the LpS and TiL organization committee to announce the award winners for 2019. For the second time in a row, after the traditional cruise on the lake from Bregenz to Lindau, the gala dinner at the Eilgut Halle has proven to being a great place for the LpS & TiL award ... Read more »

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