Power surface mount light emitting die package

• US 8,167,463 B2
• Filed: 02/08/2011
• Issued: 05/01/2012
• Est. Priority Date: 09/04/2002
• Status: Expired due to Term

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Loh, Ban P.
• Primary Examiner(s): Alavi, Ali
• Application Number:
  US13/023,268
• Publication Number:
  US 20110186896A1
• Time in Patent Office: 448 Days
• Field of Search: 362/294, 362/800, 362/326, 362/311.01, 362/311.02, 257/98, 257/100, 257/712, 257/722
• US Class Current: 362/311.02
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/641 characterized by the materials
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A light emitting die package includes a substrate, a reflector plate, and a lens. The substrate has traces for connecting an external electrical power source to a light emitting diode (LED) at a mounting pad. The reflector plate is coupled to the substrate and substantially surrounds the mounting pad, and includes a reflective surface to direct light from the LED in a desired direction. The lens is free to move relative to the reflector plate and is capable of being raised or lowered by the encapsulant that wets and adheres to it and is placed at an optimal distance from the LED chip(s). Heat generated by the LED during operation is drawn away from the LED by both the substrate (acting as a bottom heat sink) and the reflector plate (acting as a top heat sink).

Claims

1. A light emitting die package, comprising:

a substrate comprising a top surface, a bottom surface and a plurality of sides;

a thermal pad disposed in a middle portion of the bottom surface of the substrate; and

a plurality of traces disposed on opposing sides of and isolated from the thermal pad on the bottom surface of the substrate.

2. The package of claim 1, wherein the plurality of traces are also disposed on the top surface of the substrate and extend to a side of the plurality of sides and around the side to the opposing sides of the thermal pad of the bottom surface.

3. The package of claim 2, further comprising a light emitting diode (LED) mounted on the top surface of the substrate and connected to the plurality of traces.

4. The package of claim 2, wherein the portion of the plurality of traces extending around the side of the substrate comprises solder pads.

5. The package of claim 4, wherein the portion of the plurality of traces extending around the side of the substrate has spaces formed therein.

6. The package of claim 5, wherein the spaces comprise quarter-cylindrical spaces.

7. The package of claim 5, wherein the spaces comprise semi-cylindrical spaces.

8. The package of claim 1, wherein the thermal pad comprises a metal.

9. The package of claim 1, further comprising a reflector coupled to the substrate and substantially surrounding the LED, the reflector plate defining a reflection surface.

10. The package of claim 9, wherein the reflector is composed of a material having high thermal conductivity.

11. The package of claim 9, wherein the reflector plate and substrate serve as heat sinks for dissipating heat generated by the LED.

12. The package of claim 9, further comprising an encapsulant covering the LED is disposed within the reflector.

13. The package of claim 12, wherein the encapsulant is composed of an optically clear polymer material.

14. The package of claim 12, further comprising a lens covering the LED.

15. The package of claim 14, wherein the lens sits on and adheres to the encapsulant, the lens free to move as the encapsulant expands and contracts.

16. The package of claim 14, wherein the lens is formed by the encapsulant.

17. The package of claim 12, wherein the encapsulant comprises silicon.

18. The package of claim 1, wherein a lens sits on and adheres to the encapsulant and the lens is free to move relative to the substrate.

19. The package of claim 1, wherein the substrate is electrically insulating.

20. The package of claim 19, wherein the electrically insulating substrate has a high thermal conductivity.

21. The package of claim 19, wherein the electrically insulating substrate comprises aluminum nitride.

22. The package of claim 1, wherein an encapsulant covering the LED.

23. The package of claim 22, wherein the encapsulant is composed of an optically clear polymer material.

24. The package of claim 22, further comprising a lens covering the LED.

25. The package of claim 24, wherein the lens sits on and adheres to the encapsulant, the lens free to move as the encapsulant expands and contracts.

26. The package of claim 24, wherein a lens sits on and adheres to the encapsulant and the lens is free to move relative to the substrate.

27. The package of claim 24, wherein the lens is formed by the encapsulant.

28. The package of claim 22, wherein the encapsulant comprises silicon.

29. The package of claim 1, wherein the plurality of traces disposed on opposing sides of and isolated from the thermal pad are disposed on opposing ends of the bottom surface of the substrate.