Light emitting device with reflective sidewall
Embodiments of the invention include a light emitting device including a substrate and a semiconductor structure including a light emitting layer. A first reflective layer surrounds the light emitting device. A wavelength converting element is disposed over the light emitting device. A second reflective layer is disposed adjacent a first sidewall of the wavelength converting element.
1. A device comprising:
a light emitting device comprising a semiconductor light emitting layer, side walls, and a top surface;
a wavelength converting element comprising a bottom surface, a top light emitting surface, and side walls connecting the bottom surface and the top light emitting surface, each side wall of the wavelength converting element substantially aligned with one of the side walls of the light emitting device, the wavelength converting element disposed over the top surface of the light emitting device with the bottom surface of the wavelength converting element facing the top surface of the light emitting device;
a first reflective layer contacting and conforming to side walls of the light emitting device without extending along the side walls of the wavelength converting element as far as the top light emitting surface of the wavelength converting element; and
a second reflective layer disposed to contact and conform to only a first side wall of the wavelength converting element without being adjacent to a second side wall of the wavelength converting element.
2. The device of claim 1 , wherein in operation a majority of light impinging on the second reflective layer from within the wavelength converting element is reflected back into the wavelength converting element.
3. The device of claim 1 , wherein the first reflective layer does not extend along the side walls of the light emitting device as far at the top surface of the light emitting device.
4. The device of claim 1 , wherein the first reflective layer does not extend along the side walls of the light emitting device beyond the top surface of the light emitting device.
5. The device of claim 1 , wherein the wavelength converting element is formed separately from the light emitting device and attached to the light emitting device by an adhesive.
6. The device of claim 1 , wherein the second side wall of the wavelength converting element is positioned oppositely from the first sidewall of the wavelength converting element and not covered by a reflective layer.
7. The device of claim 6 , wherein the second reflective layer is arranged such that in operation a majority of light emitted toward the first sidewall is reflected into the wavelength converting element and a majority of light emitted toward the second sidewall of the wavelength converting element is extracted from the wavelength converting element.
8. The device of claim 1 , wherein the first reflective layer is at least 95% reflective.
9. The device of claim 1 , wherein the first reflective layer comprises reflective particles disposed in a transparent material.
10. The device of claim 1 , wherein the second reflective layer is disposed adjacent only a single sidewall of the wavelength converting element.
11. The device of claim 1 , wherein the second reflective layer is at least 95% reflective.
12. The device of claim 1 , wherein:
the first reflective layer does not extend along the side walls of the light emitting device beyond the top surface of the light emitting device; and
the wavelength converting element comprises a second side wall positioned oppositely from the first sidewall of the wavelength converting element and not covered by a reflective layer.
13. The device of claim 12 , wherein the second reflective layer is disposed adjacent only the first sidewall of the wavelength converting element.
14. The device of claim 12 , wherein the first reflective layer and the second reflective layer each comprises reflective particles disposed in a transparent material.
15. The device of claim 12 , wherein:
the second reflective layer is disposed adjacent only the first sidewall of the wavelength converting element; and
the first reflective layer and the second reflective layer each comprises reflective particles disposed in a transparent material.
16. A method comprising:
attaching a light emitting device to a mount, the light emitting device comprising a semiconductor light emitting layer, side walls, and a top surface;
disposing a wavelength converting element comprising a bottom surface, a top light emitting surface, and side walls connecting the bottom surface and the top light emitting surface over the light emitting device with the bottom surface of the wavelength converting element facing the top surface of the light emitting device such that each side wall of the wavelength converting element is substantially aligned with one of the side walls of the light emitting device;
forming a first reflective layer contacting and conforming to the side walls of the light emitting device without extending along side walls of the wavelength converting element as far as the top light emitting surface of the wavelength converting element; and
forming a second reflective layer disposed to contact and conform to only a first side wall of the wavelength converting element without being adjacent to a second side wall of the wavelength converting element.
17. The method of claim 16 , comprising forming the second reflective layer after forming the first reflective layer.
18. The method of claim 16 , comprising forming the first reflective layer by molding and forming the second reflective layer by jet dispensing.
19. The method of claim 16 , comprising forming the first reflective layer and the second reflective layer by different techniques.
20. The method of claim 16 , wherein the wavelength converting element is pre-formed, comprising gluing the wavelength converting element to the top surface of the light emitting device.