Encapsulant for opto-electronic devices and method for making it
First Claim
1. An encapsulant for an opto-electronic device or optical component, the encapsulant characterized by a coefficient of thermal expansion and an optical transmittance, the encapsulant comprising:
- 1) a filler consisting essentially of glass particles having diameters in the range of 1 μ
m to 500 μ
m, the glass particles formed from a glass essentially free of titania and characterized by a glass refractive index having a value in the range of 1.48 to 1.60 and a variance of less than about 0.001, wherein the filler is characterized by a filler refractive index; and
2) an epoxy, characterized by an epoxy refractive index;
wherein the coefficient of thermal expansion of the encapsulant has an average value of less 50 ppm/°
C., with a variation of less than ±
30%, and wherein the filler refractive index and the epoxy refractive index have values sufficiently similar such that the optical transmittance of the encapsulant is at least 65% when measured at a wavelength in the range of 300 nm to 800 nm at an encapsulant thickness of about 1 mm.
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Accused Products
Abstract
An encapsulant for use with opto-electronic devices and optical components incorporates a filler made from a glass that has been processed into particle form and heated to a predetermined temperature for a predetermined time, along with an epoxy having an index of refraction matched to that of the glass and heated to a predetermined temperature for a predetermined time, to prevent settling of the filler particles after mixing the filler particles with the epoxy, and thereby obtaining uniform dispersion of the particles within the epoxy. The encapsulant provides for high light transmittance, and its coefficient of thermal expansion can be varied by varying the amount of filler without substantially altering the optical properties of the encapsulant. The coefficient of thermal expansion variation within the encapsulant preferably is less than 30%, due to uniform dispersion of the filler particles within the epoxy.
31 Citations
42 Claims
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1. An encapsulant for an opto-electronic device or optical component, the encapsulant characterized by a coefficient of thermal expansion and an optical transmittance, the encapsulant comprising:
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1) a filler consisting essentially of glass particles having diameters in the range of 1 μ
m to 500 μ
m, the glass particles formed from a glass essentially free of titania and characterized by a glass refractive index having a value in the range of 1.48 to 1.60 and a variance of less than about 0.001, wherein the filler is characterized by a filler refractive index; and
2) an epoxy, characterized by an epoxy refractive index;
wherein the coefficient of thermal expansion of the encapsulant has an average value of less 50 ppm/°
C., with a variation of less than ±
30%, andwherein the filler refractive index and the epoxy refractive index have values sufficiently similar such that the optical transmittance of the encapsulant is at least 65% when measured at a wavelength in the range of 300 nm to 800 nm at an encapsulant thickness of about 1 mm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. An encapsulant for an opto-electronic device or optical component, the encapsulant characterized by a coefficient of thermal expansion and an optical transmittance, the encapsulant comprising:
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1) between 15 volume percent and 40 volume percent of a filler, the filler consisting essentially of glass particles formed from an alkali-free borosilicate glass that has been silylated with aminopropyltriethoxysilane, the particles having diameters in the range of 1 μ
m to 250 μ
m of which particles less than 10 percent by volume have diameters less than 10 μ
m, wherein the glass is characterized by a glass refractive index having a value of about 1.526 and a variance of less than about 0.001, and wherein the filler has been heated in an oxygen containing atmosphere at a temperature in the range of 450°
C. to 550°
C. for a duration in the range of 30 hours to 40 hours; and
2) between 60 volume percent and 85 volume percent of an epoxy, # thien the epoxy is prepared from a composition comprising diglycidyl ether of bisphenol-A resin, cyclo aliphatic epoxy resin, a hardener, and an accelerator, wherein the ratio by weight of diglycidyl ether of bisphenol-A resin to combined weight of diglycidyl ether of bisphenol-A resin and cyclo-aliphatic epoxy resin has a value in the range of 0.30 to 0.50, the ratio by weight of hardener to combined weight of diglycidyl ether of bisphenol-A resin and cyclo-aliphatic epoxy resin has a value in the range of 0.50 to 0.70, and the ratio by weight of accelerator to combined weight of diglycidyl ether of bisphenol-A resin and cyclo-aliphatic epoxy resin has a value in the range of 0.005 and 0.03, and wherein the coefficient of thermal expansion of the encapsulant is an average value of less the about 40 ppm/ C and a variation of less than about ±
10%, and the optical transmittance of the encapsulant is at least 80% when measured at a 1 wavelength of 650 nm at an encapsulant thickness of 1 mm.
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Specification