Sub-assembly and methods for forming the same

• US 8,231,237 B2
• Filed: 03/05/2009
• Issued: 07/31/2012
• Est. Priority Date: 03/05/2008
• Status: Active Grant

• Current Assignee: Oree Advanced Illumination Solutions Ltd.
• Original Assignee: Oree, Inc.
• Inventors: Zimmermann, Micha, Meir, Noam
• Primary Examiner(s): HAN, JASON
• Application Number:
  US12/398,635
• Publication Number:
  US 20090225565A1
• Time in Patent Office: 1,244 Days
• Field of Search: 362 971- 973, 362/249.02, 362/311.02, 362/612, 362/800, 349/69
• US Class Current: 362/97.3
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G02B 6/0083 Details of electrical connections of light sources to drivers, circuit boards, or the like
• CPC Class Codes: G02B 6/0085 Means for removing heat created by the light source from the package heat extraction or cooling elements for semiconductor light sources in general H01L33/64
• CPC Class Codes: G02B 6/0091 of the light source relative to the light guide G02B6/0021 takes precedence
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A sub-assembly matable to a waveguide having a recess therein includes a structure comprising a discrete light source disposed on a carrier, and a substrate and a heat spreader disposed beneath the structure. The structure has a contour complementary to the recess, such that, when the sub-assembly is joined to the waveguide, the discrete light source is within the waveguide.

Claims

1. A sub-assembly matable to a waveguide having a recess therein, the sub-assembly comprising:

a substrate;

a carrier having a substantially planar top surface raised above a top surface of the substrate, the carrier and the substrate being (i) different materials and (ii) discrete from each other;

a bare-die light-emitting diode disposed on and in direct contact with the substantially planar top surface of the carrier such that, when the sub-assembly is joined to the waveguide, the discrete light source is within the waveguide

an optically transparent encapsulation material entirely filling the recess to encapsulate the bare-die light-emitting diode and contacting at least one of the substrate or the carrier such that light from the bare-die light-emitting diode is efficiently coupled into the waveguide; and

a gap laterally between the carrier and the substrate, wherein a reflective material is disposed in the gap for reflecting light from the bare-die light-emitting diode into the waveguide.

2. The sub-assembly of claim 1, wherein a lateral dimension of a top surface of the carrier is at least three times a lateral dimension of the bare-die light-emitting diode.

3. The sub-assembly of claim 2, wherein the top surface of the carrier has an area at least three times an area of a top surface of the bare-die light-emitting diode.

4. The sub-assembly of claim 1, wherein the substantially planar top surface of the carrier is reflective.

5. The sub-assembly of claim 4, wherein the reflective top surface of the carrier is disposed within the recess.

6. The sub-assembly of claim 1, further comprising a reflector disposed over the substrate.

7. The sub-assembly of claim 6, wherein the reflector is in direct contact with the substrate and the waveguide.

8. The sub-assembly of claim 6, wherein a portion of the reflector is disposed within the recess.

9. The sub-assembly of claim 8, wherein the reflector is in direct contact with the substrate and the optically transparent encapsulation material.

10. The sub-assembly of claim 1, wherein the bare-die light-emitting diode is electrically connected to the carrier.

11. The sub-assembly of claim 10, wherein the bare-die light-emitting diode is electrically connected to the carrier by at least one wire.

12. The sub-assembly of claim 11, wherein at least a portion of at least one said wire is raised above and not in contact with the top surface of the carrier.

13. The sub-assembly of claim 1, wherein the substrate comprises an electrical connector for connection to an external power source.

14. The sub-assembly of claim 1, wherein the bare-die light-emitting diode occupies only a portion of the top surface of the carrier.

15. The sub-assembly of claim 1, further comprising a heat spreader disposed beneath and in contact with at least one of the substrate or the carrier.

16. The sub-assembly of claim 1, wherein the substrate is a printed circuit board.

17. The sub-assembly of claim 1, wherein the carrier comprises a ceramic material.

18. The sub-assembly of claim 1, wherein the carrier is electrically connected to the substrate by at least one wire.

19. The sub-assembly of claim 18, wherein at least a portion of at least one said wire is raised above and not in contact with the top surface of the substrate.

20. The sub-assembly of claim 1, wherein the optically transparent encapsulation material contacts both the substrate and the carrier.

21. The sub-assembly of claim 1, wherein the top surface of the carrier and the top surface of the substrate are substantially parallel.

22. The sub-assembly of claim 1, wherein the carrier is disposed upon and in direct contact with a top surface of a heat spreader comprising a thermally conductive material.

23. The sub-assembly of claim 22, wherein the substrate is disposed upon and in direct contact with the top surface of the heat spreader.

24. A method of forming a sub-assembly matable to a waveguide having a recess therein, the method comprising:

providing a carrier having a substantially planar top surface raised above a top surface of a substrate, the carrier and the substrate being (i) different materials and (ii) discrete from each other;

providing a bare-die light-emitting diode over and in direct contact with the substantially planar top surface of the carrier such that, when the sub-assembly is mated to the waveguide, the discrete light source is within the waveguide

providing an optically transparent encapsulation material entirely filling the recess to encapsulate the bare-die light-emitting diode and contacting at least one of the substrate or the carrier such that light from the bare-die light-emitting diode is efficiently coupled into the waveguide; and

providing a gap laterally between the carrier and the substrate, wherein a reflective material is disposed in the gap for reflecting light from the bare-die light-emitting diode into the waveguide.