Photon extraction from nitride ultraviolet light-emitting devices
First Claim
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1. An illumination device comprising:
- a ultraviolet (UV) light-emitting semiconductor die;
a rigid lens for extracting light from the light-emitting semiconductor die; and
a layer of encapsulant attaching the rigid lens to the light-emitting semiconductor die,wherein (i) thickness of the encapsulant is insufficient to prevent propagation of thermal expansion mismatch-induced strain between the rigid lens and the light-emitting semiconductor die, and (ii) the rigid lens has (a) a substantially hemispherical portion and (b) a substantially cylindrical portion disposed between the substantially hemispherical portion and the layer of encapsulant, the substantially cylindrical portion having a straight vertical sidewall.
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Abstract
In various embodiments, a rigid lens is attached to a light-emitting semiconductor die via a layer of encapsulant having a thickness insufficient to prevent propagation of thermal expansion mismatch-induced strain between the rigid lens and the semiconductor die.
254 Citations
24 Claims
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1. An illumination device comprising:
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a ultraviolet (UV) light-emitting semiconductor die; a rigid lens for extracting light from the light-emitting semiconductor die; and a layer of encapsulant attaching the rigid lens to the light-emitting semiconductor die, wherein (i) thickness of the encapsulant is insufficient to prevent propagation of thermal expansion mismatch-induced strain between the rigid lens and the light-emitting semiconductor die, and (ii) the rigid lens has (a) a substantially hemispherical portion and (b) a substantially cylindrical portion disposed between the substantially hemispherical portion and the layer of encapsulant, the substantially cylindrical portion having a straight vertical sidewall. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An illumination device comprising:
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a ultraviolet (UV) light-emitting semiconductor die; a rigid lens for extracting light from the light-emitting semiconductor die; and a layer of encapsulant attaching the rigid lens to the light-emitting semiconductor die, wherein (i) a thickness of the encapsulant is less than approximately 10 μ
m, and (ii) the rigid lens has (a) a substantially hemispherical portion and (b) a substantially cylindrical portion disposed between the substantially hemispherical portion and the layer of encapsulant, the substantially cylindrical portion having a straight vertical sidewall. - View Dependent Claims (20, 21, 22, 23)
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24. A method of operating an illumination device, the method comprising:
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providing an illumination device comprising; a ultraviolet (UV) light-emitting semiconductor die, a rigid lens for extracting light from the light-emitting semiconductor die, and a layer of encapsulant attaching the rigid lens to the light-emitting semiconductor die, wherein (i) a thickness of the encapsulant is less than approximately 10 μ
m, and (ii) the rigid lens has (a) a substantially hemispherical portion and (b) a substantially cylindrical portion disposed between the substantially hemispherical portion and the layer of encapsulant, the substantially cylindrical portion having a straight vertical sidewall; andoperating the light-emitting semiconductor die for at least 1000 hours to expose the rigid lens and the layer of encapsulant to UV light, wherein, after operation of the light-emitting semiconductor die, (i) a transmittance of the layer of encapsulant decreases by at least 10%, and (ii) a transmittance of the rigid lens decreases by no more than 1%.
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Specification