Light emitting diode package with enhanced heat conduction
A light emitting diode (LED) device and packaging with enhance heat conduction. An LED in a wafer level processing (WLP) package is disclosed using vias in the silicon to route the electrical connections to the LED backside and a dedicated hole in the silicon with a direct heat conduction route from the LED to the printed circuit board. Certain layers act to promote mechanical, electrical, thermal, or optical characteristics of the device. The device avoids or ameliorates heat dissipation problems found in conventional LED devices. Some embodiments include a plurality of optically permissive layers, including an optically permissive cover substrate comprising phosphors and/or quantum dots.
1. A light emitting device, comprising:
a substrate having opposing first and second substrate surfaces;
a semiconductor LED including doped and intrinsic regions thereof, said semiconductor LED having opposing first and second LED surfaces, said first LED surface disposed on the first substrate surface;
a thermally conductive layer disposed on the second LED surface of the semiconductor LED;
a carrier wafer disposed on the thermally conductive layer;
at least one optically reflective surface disposed between said carrier wafer and said semiconductor LED; and
a substantially optically transmissive layer disposed proximal to the second substrate surface,
wherein the carrier wafer and the thermally conductive layer define a relief to expose at least a portion of the second LED surface.
2. The light emitting device of claim 1 , said at least one optically reflective surface comprising metal.
3. The light emitting device of claim 1 , said at least one optically reflective surface comprising a dielectric stack.
4. The light emitting device of claim 1 , wherein said semiconductor LED is affixed to said carrier wafer with an adhesive material which has the property of high thermal conductivity.
5. The light emitting device of claim 1 , wherein said semiconductor LED is affixed to said carrier wafer with an adhesive material which has the property of optical diffusion.
6. The light emitting device of claim 1 , wherein said semiconductor LED is affixed to said carrier wafer with an adhesive material which has the property of optical reflection.
7. The light emitting device of claim 1 , wherein said semiconductor LED is affixed to said carrier wafer with an adhesive material which has the property of optical transmissivity.
8. The light emitting device of claim 1 , further comprising at least one spacer attached to said carrier wafer; whereby, said at least one optically reflective surface is affixed thereto.
9. The light emitting device of claim 1 , said thermally conductive layer comprises metal.
10. The light emitting device of claim 1 , said thermally conductive layer comprises an organic material with a physical property of high thermal conductivity.
11. The light emitting device of claim 1 , wherein the relief has a surface area displacement of 250,000 square microns.
12. The light emitting device of claim 1 , wherein the relief has a surface area displacement of at least 700 microns by 700 microns.