LED professional Review (LpR) - Articles
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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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”.
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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.
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Managing Manufacturing and Supply Chain Challenges in LED Luminaire Design by Sanmina
Today’s luminaires are often complicated lighting systems and have a wide range of applications from in-home luminaires and retail to very high power outdoor lighting. This causes several challenges in both design and manufacturing. Some of these problems may have already been solved by design and
manufacturing firms having expertise with LED luminaire design and manufacturing. Gelston Howell, Senior Vice President at Sanmina explains how to manage some of these design, manufacturing and supply chain challenges by using examples.
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Cost Saving Potential with Automation and Well Designed Processes by BJB GmbH
The manufacturing of modern LED luminaires and conventional fixtures has some similarities as well
as some distinct differences that result in added challenges. Automation, in combination with a well-conceived product design and process combined with well-matched components, allows for economical manufacturing without compromising production quality and, consequently, reliable, high performance, and high quality luminaires. Olaf Baumeister, Head of Product Development and BJB-Automation at BJB GmbH, explains and discusses technical challenges, successful concepts and solutions.
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Luminescent Glasses and Glass Ceramics for White Light Emitting Diodes by the Fraunhofer Institute and the South Westphalia University of Applied Science
Luminescent glasses or glass ceramics represent an interesting alternative to LED phosphor due to their high thermal and chemical stability. A series of rare-earth doped glasses are investigated for their potential application as photon converters for solid-state lighting applications. Franziska Steudel, Sebastian Loos, Bernd Ahrens, and Stefan Schweizer from the Fraunhofer Institute and the South Westphalia University of Applied Science respectively, show that the color coordinate of double-doped glass can be varied over a broad spectral range by changing the rare-earth doping ratio accordingly. In addition, double-doping allows for a change in the color coordinate by using different excitation wavelengths.
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Cost and Performance Optimization of Thermal Management Solution for High Power LEDs by Cambridge Nanotherm
The LED industry has a challenge. General lighting requires very bright LEDs that can replace incandescent and halogen lights. Manufacturers need efficacy, cost and manufacturability to be “just right” but most leading solutions, especially in thermal management, are short of the mark. Giles Humpston, applications engineer, Cambridge Nanotherm, discusses ways to combine performance with reasonable costs and good manufacturability.
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Potting Processes as a Part of LED-Based Lighting Module Manufacturing Methods by ViscoTec Pumpen and Dosiertechnik GmbH
Many manufacturing processes need very accurate dosing. One such dosing process concerns the potting of LED-modules. Numerous parameters affect the potting quality. Willi Huber from the Business Unit Adhesives & Chemicals at ViscoTec Pumpen- u. Dosiertechnik GmbH explains casting equipment, critical parameters and appropriate potting methods.
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Power over Ethernet Lighting for Commercial Buildings by Molex
Today, information technology (IT) and lighting are separate worlds. It is necessary to create a bridge between these worlds, not only from a technical standpoint but also from the perspective of understanding what is important to each industry. Giovanni Frezza, Group Product Manager at Molex,
discusses how LEDs and PoE may pave the way with new power standards: LEDs far outperform the lumens output of older lighting technologies. Today, the PoE standard for LED is 30 W. An UPOE standard for 60 W is in the works, and an expansion called BP is in progress for up to 95 W.
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Thin-Film Light Management System for Intelligent Large-Area LED Luminaires by the Centre Suisse d’Electronique et de Microtechnique SA
The recent advances in Solid State Lighting have triggered the development of smart lighting solutions. However, the point-like nature of LEDs imposes the use of inefficient and/or bulky light scattering sheets or costly, short-pitch LED arrays to achieve acceptable spatial luminance uniformity. Ph.D. Oscar Fernandez, Senior R&D Engineer at the Centre Suisse d’Electronique et de Microtechnique SA (CSEM) shows a new approach in the form of an innovative thin form-factor light management (LM) system comprising a highly engineered combination of thin-film diffractive nano-optical and refractive
micro-optical elements.
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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.
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