Ultraviolet emitting device with shaped encapsulant
Embodiments of the invention include a light emitting diode (UVLED), the UVLED including a semiconductor structure with an active layer disposed between an n-type region and a p-type region. The active layer emits UV radiation. The UVLED is disposed on a mount. A transparent encapsulant is disposed over the UVLED. The transparent encapsulant has an angled sidewall.
1. A device comprising:
an ultra-violet light emitting diode (UVLED) comprising a semiconductor structure comprising an active layer disposed between an n-type region and a p-type region, wherein the active layer emits UV radiation;
a mount, wherein the UVLED is disposed on a top surface of the mount; and
an encapsulant disposed over the UVLED, the encapsulant having a top surface and substantially flat sidewalls that have a roughened surface, the roughened surface comprising grooves in the sidewalls substantially perpendicular to the top surface of the mount.
2. The device of claim 1 wherein the roughened surface comprises a corrugated surface.
3. The device of claim 1 wherein the roughened surface comprises ripples.
4. The device of claim 1 wherein the sidewalls are sloped.
5. The device of claim 4 wherein the sidewalls slope outward from the top surface of the mount to the top surface of the encapsulant.
6. The device of claim 4 wherein the sidewalls slope inward from the top surface of the encapsulant to the top surface of the mount.
7. The device of claim 1 wherein the top surface of the encapsulant is also a roughened surface.
8. The device of claim 1 wherein the roughened surface comprises the grooves directly formed in the sidewalls of the encapsulant by removing portions of the encapsulant.
9. The device of claim 1 wherein an index of refraction of the encapsulant varies across a thickness of the encapsulant.
10. The device of claim 1 wherein the encapsulant has a square shape.
11. The device of claim 10 further comprising a trench formed in a top surface of the encapsulant, the trench having a square shape that surrounds the UVLED.
12. The device of claim 10 further comprising a trench formed in a top surface of the encapsulant, the trench having a cross shape.
13. The device of claim 1 wherein the encapsulant comprises a transparent material mixed with one of bubbles and beads.
14. The device of claim 1 wherein a plurality of holes are formed in the encapsulant.
15. The device of claim 1 wherein the encapsulant is pre-formed then mounted over the UVLED.
16. The device of claim 1 wherein the encapsulant is deposited as a liquid or semi-solid over the UVLED and shaped.
17. The device of claim 1 wherein the sidewalls are sloped at a constant angle.