Omnidirectional reflector
View Patent ↗A system and method for manufacturing an LED is provided. A preferred embodiment includes a substrate with a distributed Bragg reflector formed over the substrate. A photonic crystal layer is formed over the distributed Bragg reflector to collimate the light that impinges upon the distributed Bragg reflector, thereby increasing the efficiency of the distributed Bragg reflector. A first contact layer, an active layer, and a second contact layer are preferably either formed over the photonic crystal layer or alternatively attached to the photonic crystal layer.
1. A light-generating device comprising:
a substrate;
a reflective layer over the substrate;
a photonic crystal collimator layer different from the reflective layer disposed over the reflective layer, the photonic crystal collimator layer comprising a first homogenous material that extends through the photonic crystal collimator layer in a direction perpendicular to the substrate; and
a light-emitting diode over the photonic crystal collimator layer, wherein the light-emitting diode is in direct physical contact with the photonic crystal collimator layer.
2. The light-generating device of claim 1 , further comprising a metal bonding layer between the photonic crystal collimator layer and the light-emitting diode.
3. The light-generating device of claim 1 , wherein the photonic crystal collimator layer is substantially thicker than the reflective layer.
4. The light-generating device of claim 1 , wherein the reflective layer comprises a distributed Bragg reflector.
5. The light-generating device of claim 1 , wherein the photonic crystal collimator layer comprises a lattice of a first material located within a second material, the second material having a different refractive index than the first material.
6. The light-generating device of claim 1 , wherein the photonic crystal collimator layer is homogenous in a first direction and non-homogenous in a second direction and a third direction.
7. The light-generating device of claim 1 , wherein the photonic crystal collimator layer comprises GaN, Si or dielectric materials.
8. A light-generating device comprising:
a substrate;
a reflective layer over the substrate:
a collimator over the reflective layer, the collimator comprising a first material and a second material extending away from the substrate through the first material, wherein the reflective layer and the collimator have different material compositions; and
a light-emitting diode over the collimator, wherein the light-emitting diode is in direct physical contact with the collimator.
9. The light-generating device of claim 8 , further comprising a metal layer between the collimator and the light-emitting diode.
10. The light-generating device of claim 8 , wherein the collimator is substantially thicker than the reflective layer.
11. The light-generating device of claim 8 , wherein the reflective layer comprises a distributed Bragg reflector.
12. The light-generating device of claim 8 , wherein the collimator is substantially homogenous in a first direction substantially perpendicular to a surface of the collimator and non-homogenous in a second direction and as third direction, the second direction and the third direction being substantially parallel to the surface of the collimator.
13. The light-generating device of claim 8 , wherein the collimator comprises GaN, Si or dielectric materials.
14. A light-emitting device comprising:
a first substrate;
a light-emitting diode over the first substrate; and
a reflector located between the light-emitting diode and the first substrate, the reflector comprising:
a reflective layer; and
a photonic crystal layer different from the reflective layer, wherein the photonic crystal layer is a collimator and comprises a plurality of columns formed through a base material, the plurality of columns comprising a column material different from the base material
wherein the reflector is in direct physical contact with the light-emitting diode.
15. The light-emitting device of claim 14 , wherein the photonic crystal layer is located between the reflective layer and the light-emitting diode.
16. The light-emitting device of claim 15 , wherein the photonic crystal layer is at least multiple times thicker than the reflective layer.
17. The light-emitting device of claim 14 , wherein the reflective layer comprises a distributed Bragg reflector.
18. The light-emitting device of claim 14 , wherein the photonic crystal layer comprises GaN, Si or dielectric materials.
19. The light-emitting device of claim 14 , further comprising a layer of metal between the photonic crystal layer and the light-emitting diode.
20. The light-emitting device of claim 14 , wherein the photonic crystal layer is homogenous in a first direction and non-homogenous in a second direction and a third direction.