Giving LEDs a brighter future
An award-winning new technology offering enhanced thermal conductivity, developed by a Hong Kong company, is lighting up the LED business.
The technology represents a major leap forward for the High Brightness Light Emitting Diode (HBLED) market. HB-LEDS have gained importance in recent years, but their lifetime issue presented a market opening for better heat dissipation materials.
Hong Kong’s Nano and Advanced Materials Institute (NAMI) has addressed this life-span issue through the development of an advanced Die Attach Adhesive (DAA) with enhanced thermal conductivity. The technology, available on the Asia IP Exchange (AsiaIPEX), met with a strongly positive market reception, with NAMI already licensing its DAA to multiple companies and winning the Technological Achievement Award at the 2014 Hong Kong Awards for Industries.
Established in 2006, NAMI was designated by the Innovation and Technology Commission as a research and development center for nanotechnology and advanced materials. Amid the growing LED market, NAMI has focused on developing advanced thermal management materials for more reliable LED and high-power lighting devices.
NAMI Technical Manager Tracy Liu said that in HB-LED packages for solid-state lighting, effective heat dissipation is needed to meet the increasing requirement for efficiency, color and product life.
“In HB-LED packages, DAAs do more than attach the die to the substrate,” she said. “They also provide thermal and/or electrical conductivity between the die and the package, essentially affecting the operating performance of the device. Until now, most commercial DAAs had a thermal conductivity of just 2 to 8W/ mK, which is not enough for HBLED packaging.”
NAMI’s work has led to the creation of a low-cost DAA with high thermal conductivity of 30W/mK, by utilizing novel nano fillers with optimal shape, sizes and surface properties for uniform dispersion within the adhesive.
“DAA has two main parts, the organic resin part and the inorganic filler part,” Liu said. “The organic part provides the adhesion and the inorganic part provides the electrical/thermal conductivity. Currently most conventional DAAs use micrometer inorganic particles as fillers, and among the micronspheres, there will be a lot of gaps, which lower the heat dissipation ability.”
Liu said in NAMI’s Advanced DAA, nano materials were used to fill these micron-size gaps, with the result that thermal conductivity could be increased significantly. “However, when we are dispersing nano materials into the organic resin, the heat conducting materials have to be in nano size to provide uniform and controllable properties within the entire adhesive material,” she pointed out.
“The key challenge is to disperse evenly as much of these heat-conducting nano materials as possible within the adhesive without aggregation at any stage of the process. If this can be achieved, heat dissipation in high brightness LED devices is better with its extended lifetime.”
Liu said it took the company a year to develop the base technology and a further one to two years to apply DAA to actual LED devices in manufacturing. “There were many challenges along the way, e.g., different LED devices require different specific properties like curing time, viscosity and strength,” she said. “We also had to adapt to different dispensing methods. Bridging basic technology and manufacturing was far more difficult than the development of the base technology.”
Asia IP Exchange (AsiaIPEX), the region’s largest free online platform of tradable IPs, assisted NAMI in finding commercialization opportunities for its products.
“Application of NAMI’s DAA in LED is already achieved, with licensing from NAMI to multiple companies,” Liu said. “NAMI is extending its application to other high-power lighting devices, such as plasma lighting and printed circuit boards, especially those involving high-power devices that generate a lot of heat. And we are leveraging AsiaIPEX to spread our technologies to both local and foreign potential partners.”
Liu said the nanotechnology and advanced materials fi eld is growing in Hong Kong, although industrialists hesitate to use these due to a lack of understanding.
“One important part of NAMI’s role is to drive the use of these advanced materials in everyday products by working closely with industrialists in order to acquaint them with nanotechnology,” she said.
“A lack of familiarity with advanced technology and materials and the avoidance of risks are the key obstacles for the public to accept innovative technologies and products,” Liu noted. “Bridging innovative technologies and manufacturing is also a big challenge. In order to bridge this gap, NAMI actively collaborates with local enterprises to develop technologies and materials solutions that can lead to the development of a wide spectrum of products.”
The Nano and Advanced Materials Institute (NAMI) research team sees its eff orts shine bright after tackling the life span issue of LEDs with the advanced Die Attach Adhesive.
NAMI has focused on developing advanced thermal management materials for reliable LED and high-power lighting devices, and is being assisted by AsiaIPEX on commercialization opportunities.