Micro-reflectors on a substrate for high-density LED array

• US 20050218468A1
• Filed: 03/18/2005
• Published: 10/06/2005
• Est. Priority Date: 03/18/2004
• Status: Active Grant

• Current Assignee: Phoseon Technology, Inc.
• Original Assignee: Phoseon Technology, Inc.
• Inventors: Anderson, Duwayne R., Owen, Mark D., McNeil, Thomas R., Schreiner, Alexander F.
• Granted Patent: US 7,638,808 B2
• Time in Patent Office: Days
• US Class Current: 257/433
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/64 Heat extraction or cooling elements

Abstract

The present invention provides an optical array module that includes a plurality of semiconductor devices mounted on a thermal substrate formed with a plurality of openings that function as micro-reflectors, wherein each micro-reflector includes a layer of reflective material to reflect light. Such material preferably is conductive so as to provide electrical connection for its associated semiconductor device.

Claims

1. An optical array module, the module being used for applications requiring relatively high optical power density applied to a working surface of a target, for the purpose of illuminating or performing a material transformation in or of the target, the module comprising:

a plurality of micro-reflectors,

a plurality of semiconductor devices, wherein a selected number of such plurality of semiconductor devices are associated with one such micro-reflector, wherein the light from such selected number of semiconductor devices is substantially reflected by the one such micro-reflector so as to enhance the optical power density from such selected number of semiconductor devices, whereby the optical power density applied to the working surface is increased.

2. The optical array module of claim 1, wherein the micro-reflectors are arranged in an array having a center-to-center spacing of about 3 mm or less.

3. The optical array module of claim 1, wherein the micro-reflectors are about 700 square microns.

4. The optical array module of claim 1, wherein each micro-reflector is formed in a truncated pyramidal shape.

5. The optical array module of claim 4, further comprising a substrate, the substrate having a plurality of openings in its surface, the openings having a substantially square at the surface, and having sidewalls cut into the substrate that slope to a base, so as to create a truncated pyramidal shape and wherein each micro-reflector is formed in respective such opening.

6. The optical array module of claim 1, wherein each micro-reflector is formed having a parabolic shape.

7. The optical array module of claim 1, further including an array of micro-lenses, and one or more micro-reflectors is associated with a respective micro-lens, so as to collect and collimate light from one or more such semiconductor devices.

8. The optical array module of claim 1, wherein the micro-reflector includes a layer of reflective material, such reflective material reflecting selected wavelength(s) of light from the semiconductor device.

9. The optical array module of claim 8, wherein the reflective material includes silver or aluminum, whereby selected wavelength(s) in the UV spectra may be reflected.

10. The optical array module of claim 8, wherein the reflective material includes gold, whereby selected wavelength(s) in the visible spectra may be reflected.

11. The optical array module of claim 1, further comprising a substrate and a material layered on such substrate, the material having a plurality of openings in its surface, wherein each micro-reflector is formed in respective such opening.

12. The optical array module of claim 11, wherein the openings enter the substrate.

13. The optical array module of claim 1, wherein the micro-reflector includes a layer of conductive material, the conductive material providing electrical connection for its associated semiconductor devices.

14. The optical array module of claim 13, wherein the micro-reflector includes a layer of reflective material, such reflective material and the conductive material being the same layer.

15. A method of manufacturing an optical array module, comprising:

providing a substrate,

forming a plurality of openings in the substrate,

providing a layer of reflective material in each opening, and

mounting a semiconductor device within each opening so that the layer of reflective material in each opening reflects light from its associated semiconductor device.

16. The method of claim 15, wherein the openings in the substrate are formed by a crystallographic etching process.

17. The method of claim 16, wherein the openings have sidewalls having a characteristic slope.

18. The method of claim 17, wherein the sidewalls slope at an angle of about 54.7 degrees.

19. The method of claim 15, wherein the openings in the substrate are formed by a machining process.

20. The method of claim 19, wherein the openings have a parabolic shape.

21. The method of claim 15, wherein the openings are formed in an array having a center-to-center spacing of about 800 microns (0.032 in.).

22. The method of claim 15, wherein the substrate is formed from one of silicon, SiC, diamond, AlN, Al203, or BeO.

23. The method of claim 15, wherein each semiconductor device has a height and each opening has a depth, the height of each semiconductor device being substantially equal to the depth of each opening.

24. The method of claim 16, wherein each micro-reflector is formed in a truncated pyramidal shape.

25. A system, the system providing for illumination and performance of material transformation in or of a target, the target having a working surface to which the system is required to apply a relatively high optical power density, the system comprising an optical array module, the module having:

a plurality of micro-reflectors,

a plurality of semiconductor devices, wherein a selected number of such plurality of semiconductor devices are associated with one such micro-reflector, wherein the light from such selected number of semiconductor devices is substantially reflected by the one such micro-reflector so as to enhance the optical power density from such selected number of semiconductor devices, whereby the optical power density applied to the working surface is increased.