Recently in R&D Research of LEDs Category

A Whiter LED Light Technique

White LEDs show promise as a brighter, longer-lasting and more energy-efficient light source than conventional lighting, such as incandescent and fluorescent lights, which they may replace in the future. But scientists have had difficulty producing white LEDs that are suitable for practical use. Existing technologies produce tinted shades of white light, require complex components, and become unstable over time.


Researchers have developed a new, simpler white LED that shows promise as a more efficient and stable source of pure white light for improved illumination of homes and offices. (Credit: The American Chemical Society)

White-light-emitting single molecules are promising materials for use in a new generation of displays and light sources because they offer the possibility of simple fabrication with perfect color reproducibility and stability. To realize white-light emission at the molecular scale, thereby eliminating the detrimental concentration- or environment-dependent energy transfer problem in conventional fluorescent or phosphorescent systems, energy transfer between a larger band-gap donor and a smaller band-gap acceptor must be fundamentally blocked.

Orange + Blue = White

A new, simpler white LED that is the first to achieve stable white light emissions using a single molecule. Their specially engineered molecule combines two light-emitting materials, one orange and one blue, which together produce white light over the entire visible range. In laboratory studies, the scientists showed that light production from an LED using the new molecule was highly efficient and had excellent color stability and reproducibility, features that make it a practical white light source.

Reference:
  1. Park et al. A White-Light-Emitting Molecule: Frustrated Energy Transfer between Constituent Emitting Centers. Journal of the American Chemical Society, 2009; 090610145759060 DOI: 10.1021/ja902533f
Adapted from materials provided by American Chemical Society.



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Heatron design and development services for LED lights

Heatron is actively manufacturing custom heating components utilizing many different technologies.

Heatron offers a wide range of design and development services, technology competencies including optics, thermal management, power sources and drivers, cost effective production and assembly capabilities and in-depth industry and technology expertise.

Thermal Management Technology

Using a thermal management technology, featuring their proprietary ELPOR® coating, Heatron can provide custom designed assemblies, utilizing an automated SMT line and hot bar solder capabilities.

This would include placement of LEDs and other electronic components.

The ELPOR® system offers the unique capability of printing and laser trimming resistors as part of the LED Light Engine. Custom shapes in steel, aluminum, and ceramic substrates are available.

Heatron's new LED Design Center offers industry-leading design facilities to accommodate the most complex of projects.

From concept drawings to finished assemblies, Heatron allows the lighting designers to sit in the driver's seat and Accelerate the High Power LED Revolution.

Heatron, Inc.
3000 Wilson Avenue
Leavenworth, KS 66048
Tel: 913.946.1377

http://www.heatron.com



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Illumination Optics provides custom engineered optical solutions to manufacturers of illumination devices as well as OEM's of equipment with integrated illumination devices.

Markets served:
  - Vehicle lighting to DOT, SAE and ECE specifications
  - Street and pathway lighting
  - Aircraft lighting
  - Medical devices
  - Architectural luminaires

Light sources we work with include:
  - Incandescent
  - Fluorescent and CCFL
  - HID
  - LED

Optical techniques employed include:
  - Reflector optics
  - Refractive optics
  - TIR optics

Illumination Optics provides engineered solutions that integrate optical, thermal and electronic components in a practical package.


Illumination Optics
10437 Innovation Drive, Suite 303
Wauwatosa, WI 53226
(414) 526-9169
http://www.illuminationoptics.com/



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Relume has grown into a full-service, single source for innovative LED light engine solutions for corporate signage, automotive, airlines, safety devices and the U.S. military.

Advanced Research and Development facilities and state-of-the-art manufacturing are under the same roof to  assure maximum quality, consistency and performance of all Relume light engine solutions from concept to completion.

Relume claims to be the only company that offers the unique advantages of their patented "Silver Strips" and custom "Silver Circuit Boards" which enable LEDs to burn brighter, last longer and cost less.   Relume sets new industry standards for performance, ruggedness and economy.

Relume Technologies
Corporate World Headquarters
925 N. Lapeer Road Suite B
Oxford, MI. 48371
Phone: (248) 969-3800
www.relume.com
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LED Assemblies From Marktech Optoelectronics

Marktech Optoelectronics specializes in solving challenging LED design, assembly and manufacturing problems for customers. Marktech strives to  integrate these processes into customers' systems to provide dependable, efficient service.

Marktech, a CREE Solution Provider, offers a comprehensive range of Engineering and Manufacturing services that simplify LED product development and provide meaningful time and cost savings to OEM customers. Our vertically-integrated services provide customers with a total design, manufacturing, and logistics solution that move a product from its initial design through volume production, test, and distribution. These integrated services allow us to design, build, and ship a complete product efficiently, effectively and at a greater cost savings to our customers.

LED Assemblies Advantages

  • Low Cost, High Quality LED Manufacturing Services,
  • Extensive LED Circuit Design, and Engineering Capabilities,
  • Cost-effective LED Component Solutions,
  • No Communication Barriers - You Deal Direct with a US Based Company

Marktech's Logistics management team implements and controls the efficient and effective flow of all information between the end customer and the manufacturing plant. Prototype to Production - We make sure your products remain consistent and of the highest quality with in-house Quality Control and Inspection.

Marktech Optoelectronics
3 Northway Lane North
Latham, New York 12110
Toll Free: 800.984.5337
Phone: 518.956.2980
http://www.ledassemblies.com/


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One-stop-shop for Engineering and Production of LED lighting modules and electronics

LED Specialists is a CREE Solutions Providers that provides LED product design, integration and support services for the lighting industry. Our broad expertise in LED light sources, optics, drive electronics and thermal management allow us to deliver solutions optimized for the application and environment. In addition to engineering services, we offer complete lighting products and core components. 

Partnerships include Cree, Luxeon, Arrow Aces and NuSolutions Network.

Services include:

Product Development - Concept -> Prototype -> Detailed Design -> Manufacturing
LED Driver Electronics - Customized to achieve efficiency, cost and performance requirements.
Optical Design - To maximize lighting effectiveness.
Mechanical Design - Housings and thermal management.
Integration - Into your luminaire or system
Prototypes - Rapid turn-around and application assessment.
Test and Evaluation
Qualification and Certification
Project/Program Management
Manufacturing

LED Specialists, Inc
7A Main Street
Kings Park, New York 11754
(888) 680-1200
http://www.ledspecialists.com/



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Gallium nitride (GaN) HEMT transistors by Cree are designed for use in WiMAX applications covering the 4.9 to 5.8GHz frequency band.

The new transistors, CGH55015F and CGH55030F, are the first released GaN HEMT WiMAX products specified to operate at up to 5.8 GHz, a performance level that further demonstrates Cree’s leadership in GaN technology.

Significant potential benefits offered by the new 15-watt and 30-watt devices include:

* A four-fold increase in efficiency compared with similar power level GaAs MESFET devices
* Elevated frequency operation compared with commercially available silicon LDMOS
* Operational capability in the license-exempt 5.8 GHz ISM (industrial, scientific and medical) band as well as 5.3-GHz and 5.47-GHz U-NII (Unlicensed National Information Infrastructure) bands
* Superior linearity of better than 2.5% EVM at average power under a WiMAX signal at 25% drain efficiency covering an instantaneous bandwidth of 5.5 to 5.8 GHz.

Both transistors are available with “reference design” amplifier platforms.

As business and residential customers continue to demand increased capacity and functionality for wireless networks, these transistors can enable efficient power amplifiers in small base-station formats (access points) for last-mile service utilizing WiMAX-based architectures. Such outdoor units can allow Internet service providers to maximize their ROI on spectrum due to the ability to offer tiered services (enabled by improved quality of service and wider channel bandwidths) to hundreds of broadband users from a single access point.

“The CGH55015F and CGH55030F are two great examples of new GaN transistors Cree developed to support the higher operational frequency and stringent efficiency and linearity requirements needed to enable next-generation WiMAX base stations and access points,” said Jim Milligan, Cree’s director of RF and microwave products. “These 5-GHz transistors complement the CGH35060 product that we are also releasing now to round out our 3.5-GHz GaN HEMT WiMAX product line. This 60-watt product is a direct result of customer feedback and offers customers greater flexibility for 3.5-GHz WiMAX applications, particularly in Europe where remote radio heads (RRHs) are increasingly being used.”

Additional information about the Cree products may be obtained by calling Cree at 919-287-7505 or by visiting www.cree.com.


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Shorten the development cycle for monolithic microwave integrated circuits (MMIC)

Cree has developed a leading-edge process design kit (PDK) for GaN HEMT process technology. The Cree PDK, developed for use with Advanced Design System (ADS) from Agilent Technologies, Inc., can enable radio-frequency (RF) and microwave designers to shorten the development cycle for monolithic microwave integrated circuits (MMIC) used in high-power, high-performance electronic systems, resulting in a highly productive design flow.

The Cree GaN kit includes microstrip lines, discontinuities, scalable capacitors, inductors and resistors, pads, vias, airbridges and active devices (HEMTs) at multiple biases.

Cree’s GaN foundry is the world’s first state-of-the-art, wide-bandgap MMIC facility, and our GaN-on-silicon carbide devices have significantly higher power density, thermal conductivity and operating voltage than traditional GaAs or Silicon MMIC technologies. RF designers can take advantage of this PDK to create MMICs for high-power commercial wireless, wideband military, electronic-warfare and radar applications.

Electronic design automation (EDA) technology

“We are pleased to offer access to our GaN MMIC foundry capability through the Advanced Design System. This kit allows our customers to take advantage of an industry-leading electronic design automation (EDA) technology that provides seamless schematic through layout interoperability with design rule checking (DRC). This integrated design flow can help accelerate our customers’ time-to-market by offering an accurate and productive work environment,” said Jim Milligan, director of RF and microwave products at Cree.

MMIC design solution

“GaN is becoming more and more important in the industry. With Cree’s GaN process, our mutual customers have access to a powerful MMIC design solution in an integrated flow for leading-edge, high-power applications,” said Anitha Swaminathan, foundry program manager with Agilent’s EEsof EDA division.
For additional information about the Cree PDK, please call (919) 287-7816 or visit www.cree.com.

About Agilent
Agilent EEsof EDA is an industry-leading provider of RF-mixed signal circuit and system-design software. Agilent ADS offers powerful simulation, schematic and seamless integration with layout and DRC capability for complete front-to-back MMIC design in an integrated flow. For more information about Agilent's EDA solutions, visit www.agilent.com/find/eesof.

About Cree
Cree is leading the LED lighting revolution and setting the stage to obsolete the incandescent light bulb through the use of energy-efficient, environmentally friendly LED lighting. Cree is a market-leading innovator of lighting-class LEDs, LED lighting retrofit solutions, and semiconductor solutions for backlighting, wireless and power applications.

Cree’s product families include recessed LED down lights, blue and green LED chips, high-brightness LEDs, lighting-class power LEDs, power-switching devices and radio-frequency/wireless devices. Cree solutions are driving improvements in applications such as general illumination, backlighting, electronic signs and signals, variable-speed motors, and wireless communications.

For additional product and company information, please refer to www.cree.com.


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JUNE 12, 2008 — Cree, Inc. (Nasdaq: CREE)  introduced the world’s first commercially available GaN monolithic microwave integrated circuit (MMIC) amplifiers.

These two “catalog” MMICs integrate Cree’s proven GaN RF transistor technology with a variety of other circuit elements to form fully integrated amplifier circuits. This allows for a dramatic reduction in size and increase in performance over hybrid amplifiers.

Many RF integrated circuits can now be identically replicated on a single silicon carbide (SiC) substrate in a production process similar to that used for commercial microprocessors.

The new broadband power amplifier MMICs, the CMPA0060005 and CMPA2560025, are now available for sample release in packaged and die formats.

The CMPA0060005 is a wideband 5-watt distributed amplifier operating from DC to 6 GHz. The CMPA2560025 is a higher-power, 25-watt reactively matched amplifier operating from 2.5 to 6 GHz. Both MMICs are suitable for a variety of applications where high power over broad bandwidths is required. As an example, a pair of CMPA2560025s driven by a CMPA0060005 can provide over 40 dB gain with an output power up to 50 watts in the 2.5 to 6-GHz band.

Standard Full-Wafer (SFW) MMIC Foundry Service

Cree also announces the expansion of its standard full-wafer (SFW) MMIC Foundry service to include shared multi-project (SMP) “pizza mask” foundry runs on a quarterly basis. This SMP service is available for both SiC MESFET and GaN HEMT MMIC processes.

“The introduction of the industry’s first off-the-shelf ‘catalog’ GaN MMICs continues to set Cree apart as the industry’s leader in wide bandgap MMIC technology,” said Jim Milligan, Cree director of RF and microwave products. “These products can provide our customers with the performance improvement and size-reduction benefits of microwave circuit integration in convenient ‘drop-in’ 50-ohm amplifiers. Further, our new SMP foundry service will be ideal for lower-cost prototyping of SiC or GaN MMICs by allowing customers to purchase a portion of a shared multi-project wafer.”

“This MMIC milestone is the culmination of many years of internal investment and external support from the U.S. Department of Defense, the Title III Office, and the Defense Advanced Research Projects Agency (DARPA). These efforts are beginning to pay off for both the military and commercial markets,” said John Palmour, Ph.D., executive vice president for advanced devices at Cree.

Features of the GaN RF MMICs include:

CMPA0060005 GaN MMIC
* Wideband distributed amplifier covering DC – 6 GHz
* Up to 5 watts of CW RF output power
* High wideband DC to RF efficiency (typically 25%)
* 28 to 48-volt operating voltage range

CMPA2560025 GaN MMIC
* Broadband reactively matched amplifier covering 2.5 – 6 GHz
* Up to 25 watts CW RF output power
* Outstanding broadband DC to RF efficiency (typically 30-45%)
* 28-volt operating voltage


Cree’s product families include recessed LED down lights, blue and green LED chips, high-brightness LEDs, lighting-class power LEDs, power-switching devices and radio-frequency/wireless devices. Cree solutions are driving improvements in applications such as general illumination, backlighting, electronic signs and signals, variable-speed motors, and wireless communications.

For additional product and company information, please refer to www.cree.com.
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Understanding Power LED Lifetime Analysis

How intuitive graphical data sets help lighting designers accurately predict power LED reliability in different operating environments.


When designing LED-based lighting systems, engineers need to understand LED lumen maintenance and mortality in similar terms to those used when designing with conventional light sources. However, comparable data has been nearly impossible to find. In addition, designers need extra information to predict the lifetime of LEDs under a variety of operating conditions. A number of techniques to predict LED lifetimes have been proposed, but these have not been sufficient to generate the clear and unambiguous data that lighting engineers can use easily. This white paper provides lighting designers with an understanding of a new tool introduced by Philips Lumileds Lighting Company that simplifies the process allowing full flexibility in design options. This one tool provides designers with information that they need to make decisions about product lifetimes, driver constraints, number of LEDs required, and thermal management.

1. Aging and failure modes of lighting sources
2. Established lighting industry definitions of useful life
3. Established LED industry definitions: Lumen maintenance
4. Understanding LED operation and lifetimes
5. Completing the expression for lumen maintenance
6. Designing with B/L data for optimal lighting performance
7. Predicting LED lifetimes

Conclusion
The lighting industry needs LED manufacturers to provide data that is compatible with current design practice. However, this only answers a part of the challenge. LED vendors should also be in a position to provide more detailed information about product lifetimes under various operating conditions. This data allows lighting designers to deliver the best combination of purchase price, lighting performance, and cost of ownership for the life of the product.

From a user’s perspective, this data is most usefully expressed as a combination of B- and Llifetime as junction temperature and forward current are varied. This allows the system designer to make intelligent choices about the number of LEDs required, how they are driven, and the operating temperature.

Every power LED customer should therefore expect their supplier to provide this data as a matter of course, in any combination of B, L, Tj and If values, with clear definitions of failures (e.g. lumen maintenance below specified condition, electrical failures).


Download the PDF report "Understanding Power LED Lifetime Analysis"

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