Process for making encapsulant for opto-electronic devices
First Claim
1. A method for making an encapsulant for an opto-electronic device or optical component, comprising:
- processing a glass characterized by a glass refractive index having a value in the range of 1.48 to 1.60 with a variance of less than about 0.001 to form filler particles from the glass having diameters between 1 μ
m and 500 μ
m and characterized by a filler refractive index;
heating the filler particles in an oxygen-containing atmosphere;
preparing an epoxy including at least a curing agent and characterized by an epoxy refractive index, wherein the filler refractive index and the epoxy refractive index are sufficiently similar such that the encapsulant has optical transmittance of 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;
heating the epoxy to a predetermined temperature for a predetermined duration sufficient to increase the viscosity of the epoxy to a level such that the epoxy is characterized by a settling velocity equal to or greater than a predetermined value;
mixing the epoxy with the filler particles within a predetermined mixing duration to form the encapsulant;
cooling the encapsulant to a predetermined temperature sufficient to increase the viscosity of the epoxy in the encapsulant within a predetermined cooling duration; and
removing air bubbles from the encapsulant within a predetermined defoaming duration.
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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.
16 Citations
33 Claims
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1. A method for making an encapsulant for an opto-electronic device or optical component, comprising:
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processing a glass characterized by a glass refractive index having a value in the range of 1.48 to 1.60 with a variance of less than about 0.001 to form filler particles from the glass having diameters between 1 μ
m and 500 μ
m and characterized by a filler refractive index;heating the filler particles in an oxygen-containing atmosphere; preparing an epoxy including at least a curing agent and characterized by an epoxy refractive index, wherein the filler refractive index and the epoxy refractive index are sufficiently similar such that the encapsulant has optical transmittance of 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; heating the epoxy to a predetermined temperature for a predetermined duration sufficient to increase the viscosity of the epoxy to a level such that the epoxy is characterized by a settling velocity equal to or greater than a predetermined value; mixing the epoxy with the filler particles within a predetermined mixing duration to form the encapsulant; cooling the encapsulant to a predetermined temperature sufficient to increase the viscosity of the epoxy in the encapsulant within a predetermined cooling duration; and removing air bubbles from the encapsulant within a predetermined defoaming duration. - 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)
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33. A method for making an encapsulant for an opto-electronic device or optical component, comprising:
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processing a borosilicate glass characterized by a refractive index having a value of about 1.526 when measured at a wavelength of about 588 nm and a variance of less than about 0.001, to form borosilicate glass particles having diameters between 1 μ
m and 250 μ
m, such that less than 60 percent by volume of the borosilicate glass particles have diameters less than 10 μ
m;heating the borosilicate glass particles to a temperature between 450°
C. and 550°
C. for a duration between 30 hours and 40 hours in an oxygen-containing atmosphere;reacting the borosilicate glass particles with aminopropyltriethoxysilane; preparing an epoxy by mixing; a) diglycidyl ether of bisphenol-A resin; b) cyclo-aliphatic resin; c) hexahydrophthalic anhydride curing agent; and d) triphenyiphosphite catalyst; heating the epoxy to about 100°
C. for a duration sufficient to increase the viscosity of the epoxy to between 750 cP and 10,000 cP to obtain a settling velocity of the borosilicate glass particles in the epoxy of less than 4 mm/min;mixing the epoxy and the borosilicate glass particles; cooling the encapsulant to a temperature sufficient to further increase the viscosity of the liquid epoxy to a level between 7,000 cP and 12,000 cP; and removing air bubbles from the encapsulant; such that the steps of mixing, cooling, and removing have a combined duration of less than about 30 minutes.
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Specification