【摘 要】
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For the poor resistance to heat and light damage as well as the warpage limitation,traditional thermoplastic reflecting material for LED leadframe reflector,such as Polyphthalamide (PPA) and Poly1,4-c
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For the poor resistance to heat and light damage as well as the warpage limitation,traditional thermoplastic reflecting material for LED leadframe reflector,such as Polyphthalamide (PPA) and Poly1,4-cyclohexylene dimethylene terephthalate (PCT) cannot meet the higher and higher performance requirement raised by LED market.While epoxy molding compound,due to its merits of good resistance to heat and light damage as well as good reliability and warpage compared to the thermal plastic materials,has becoming the mainstream of LED leadframe reflector.Here,factors influencing the reflectance of white epoxy molding compound including epoxy resin,reflecting packing type and the content of the reflecting packing have been investigated.When the filler content is 83%,reflective packing content is 25%,the initial reflectance of the epoxy molding compound all above 90% after molding.Epoxy resin B disclosed higher reflectance at 450nm after aged at 150℃ for 1000h with the value of 70% while resin A of 50%.However resin B displayed higher water absorption than resin A.At the same time,Reflecting packing R1 only modified by alumina together with R4 which was modified by alumina and organics showed the lowest reflection after aging test,and then is R2 modified by silica and alumina,while R3 modified by silica,alumina and organics disclosed the highest value.At last,with the increasing of the content of reflective packing,the spiral flow of the epoxy molding compound shortened significantly,and the reflectance of the epoxy molding compound increased from 31% to 68% at 450nm after aged 150℃ for 1000h when the reflective packing increased from 10% to 25%.
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