Illumination device for providing directionally guided light
View Patent ↗In accordance with the invention, an illumination device comprises a highly thermally conductive substrate having a surface, a plurality of light emitting diodes (LEDs) supported by the surface and arranged in an array to provide illumination. At least one reflective barrier at least partially surrounds each LED. The reflective barrier is shaped to reflect away from the LED light emitted by other LEDs in the array. Advantageously the LEDs and reflective barrier are thermally coupled to a heat spreader to dissipate heat generated by the LEDs. The substrate preferably comprises an LTTC-M heat spreader, and the reflective thermal barriers preferably comprise metal ridges or cups.
1. A method for fabricating an illumination device, the method comprising the steps of:
providing a substrate, an LED die and a reflector, the reflector comprising an aperture disposed therethrough;
depositing a bonding material on a portion of the substrate;
placing the reflector onto the bonding material, wherein a portion of the bonding material fills at least a portion of the aperture;
placing an LED die overlying the aperture and in contact with the bonding material; and
bonding the reflector and LED die to the substrate with the bonding material.
2. The method of claim 1 , wherein the bonding material comprises uncured epoxy and the step of bonding the reflector and LED die to the substrate comprises curing the epoxy.
3. The method of claim 2 , wherein the epoxy is electrically conductive.
4. The method of claim 1 , wherein the aperture has a width smaller than the width of the LED die.
5. The method of claim 1 , wherein the bonding material comprises molten solder and the step of bonding the reflector and LED die to the substrate comprises cooling the solder to a solid state.
6. The method of claim 1 , wherein the reflector comprises a reflective cup.
7. The method of claim 1 , wherein a portion of the LED die is bonded directly to the substrate through the aperture.
8. The method of claim 1 , wherein the reflector comprises a thermally conductive material.
9. The method of claim 1 , wherein the substrate comprises a printed wire board (PWB).
10. The method of claim 1 , wherein the substrate comprises an electrically-conducting metallic layer.
11. The method of claim 1 , wherein the LED die comprises a metal heat-spreading film.
12. The method of claim 1 , wherein the reflector comprises a stamped metal sheet.
13. The method of claim 1 , wherein the reflector comprises a wedge-shaped sector cup.
14. The method of claim 13 , wherein the reflector comprises a side surface shaped to direct light provided by the at least one LED die at an inclination angle.
15. The method of claim 13 , wherein the LED die is electrically connected to a conductor by a wire bond passing through an opening in a side surface of the reflector.
16. The method of claim 1 , wherein the aperture is disposed through an angled surface of the reflector, and the LED die is placed on the angled surface.
17. A method for fabricating an illumination device, the method comprising the steps of:
providing a substrate, a plurality of LED die and a stamped metal sheet comprising a plurality of reflectors, wherein each reflector comprises an aperture disposed therethrough;
depositing a bonding material on a portion of the substrate;
placing the stamped metal sheet onto the bonding material, wherein a portion of the bonding material fills at least a portion of one or more apertures;
placing one or more of the plurality of LED die overlying one or more apertures and in contact with the bonding material; and
bonding the stamped metal sheet and plurality of LED die to the substrate with the bonding material.
18. The method of claim 17 , wherein the aperture has a width smaller than the width of the LED die.
19. The method of claim 17 , wherein the bonding material comprises uncured epoxy and the step of bonding the reflector and LED die to the substrate comprises curing the epoxy.
20. The method of claim 17 , wherein the bonding material comprises molten solder and the step of bonding the reflector and LED die to the substrate comprises cooling the solder to a solid state.
21. An illumination device for providing directionally guided light, the device comprising:
a substrate comprising a conductive portion;
a reflective cup bonded to the substrate by an electrically conductive bonding material, wherein the reflective cup comprises a bottom surface including at least one angled portion having a first opening, and a side surface including a second opening; and
an LED die disposed overlying the first opening of the at least one angled portion and electrically coupled to the substrate by the conductive bonding material, wherein a wire bonded to the LED passes through the second opening.
22. The device of claim 21 , wherein the bonding material comprises epoxy.
23. The device of claim 22 , wherein the epoxy is electrically conductive.
24. The device of claim 21 , wherein the bonding material comprises solder.
25. The device of claim 21 , wherein the substrate comprises a thermally conductive material.
26. A method for fabricating an illumination device, the method comprising the steps of:
providing a substrate having a cavity;
metallizing at least a portion of the cavity with a reflective material; and
disposing a molten reflecting metal in the cavity such that the molten reflecting metal forms two or more curved surfaces.
27. The method of claim 26 , further comprising the step of disposing a support structure in the cavity to provide support for the two or more curved surfaces.
28. The method of claim 27 , wherein the support structure comprises solder.
29. The method of claim 27 , wherein the support structure comprise a column.
30. The method of claim 27 , wherein the support structure comprises a solder ball.
31. The method of claim 26 , wherein the cavity is formed on a surface of the substrate.