Encapsulating material improves reliability of high brightness LEDs
Low gas permeability is one of the important characteristics sought in LED encapsulating material along with high photo-thermal stability in withstanding high temperatures and excellent retention of its initial optical transparency throughout the lifetime of the device. With an encapsulating material that has high gas permeability, it is known that gases such as oxygen can easily permeate and cause oxidation and sulfuration to occur, and that can lead to the possibility of degradation in light intensity.
The newly developed silicone encapsulating material from Shin-Etsu Chemical greatly reduces the level of gas permeability to 1/10 while maintaining heat resistance at the same level as that of the methyl-group. In addition, when compared with the phenyl group, this new product has the same level of gas permeability and much higher resistance to high temperatures. LED packaging materials that apply this product will achieve dramatically improved reliability of LED lighting because of its effectiveness in preventing the degradation of light intensity caused by the corrosion of the peripheral materials.
Because this new product has a refractive index of 1.38, which is lower than that of the methyl-group material, and is superior in transparency, it is a particularly attractive encapsulating material for flat-package HBLEDs. There are two types of products in this new series that are formulated based on different hardness properties: “KER-7080 A/B” has a hardness level of (Durometer A) 80, and “KER-7030 A/B” has a hardness level of (Durometer A) 30.
In addition to the new encapsulating material, Shin-Etsu Chemical has a group of other diverse silicone encapsulating materials for HBLED applications. Representative products in the “SCR Series” are increasingly being adopted for backlighting applications in mobile phones and notebook PCs, and products in the “ASP Series,” which have superior characteristics with regard to long-term reliability and possess greatly reduced gas permeability, also are being increasingly adopted, mainly for applications in backlighting for LCDs.
The company is currently beginning sample shipments, mainly for applications in LED lighting.
For more information, visit www.shinetsu.co.jp
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