Patent ID: 7311972

Claim:
An encapsulant for an optoelectronic device or optical component, the encapsulant characterized by a coefficient of thermal expansion and an optical transmittance, the encapsulant comprising: a filler consisting essentially of glass particles having diameters smaller than 250 μm, wherein the glass particles: are characterized by a glass refractive index having a value in the range of 1.48 to 1.60; consist essentially borosilicate; and comprise 10% to 50%, by volume, of the total volume of the encapsulant; and an epoxy resin composition at a cured stage, characterized by a refractive index of the epoxy resin composition at a cured stage; wherein the coefficient of thermal expansion of the encapsulant has an average value of less than 50 ppm/° C., with a variation of less than ±30%; wherein the glass refractive index and the refractive index of the epoxy resin composition at a cured stage have values sufficiently similar such that the optical transmittance of the encapsulant is at least 20% when measured at a wavelength in the range of 400 nm to 900 nm at an encapsulant thickness of about 1 mm; and wherein the encapsulant has been prepared by mixing an epoxy resin composition with the filler, wherein the viscosity of the epoxy resin composition prior to the mixing has a value in the range of 300 cP to 40,000 cP and wherein the epoxy resin composition comprises at least one hardener, at least one accelerator, and a ternary epoxy mixture consisting of a bisphenol-A epoxy resin, a cyclo-aliphatic epoxy resin, and triglycidyl isocyanurate resin.