Shin-Etsu Chemical Develops New Generation of Low Refractive Index Silicone Encapsulating Material

Shin-Etsu Chemical Co., Ltd. has developed a new silicone encapsulating material product for applications in packaging materials for HBLEDs (High Brightness Light-Emitting Diodes), the "KER-7000 Series," which is a low refractive index (RI)-type that greatly reduces gas permeability. The company is beginning sample shipments, mainly for applications in LED lighting.

Low gas permeability is one of the important characteristics sought in LED encapsulating material along with superb 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 well known that such gases as oxygen can easily permeate and cause oxidation and sulfuration to occur, and that can lead to the possibility of degradation in light intensity.

Up to now, Shin-Etsu Chemical has been developing many silicone encapsulating materials that have various characteristics, such as methyl-group material that is superior in heat resistance and phenyl-group material that is characterized by low gas permeability. The newly developed silicone encapsulating material product succeeds in greatly reducing the level of gas permeability by 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 intensify 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 silicone encapsulating material product series that is being announced in this press release, 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.
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