Power surface mount light emitting die package

• US 20040041222A1
• Filed: 05/27/2003
• Published: 03/04/2004
• Est. Priority Date: 09/04/2002
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Loh, Ban P.
• Granted Patent: US 7,264,378 B2
• Time in Patent Office: Days
• US Class Current: 257/433
• CPC Class Codes: H01L 2224/48091 Arched
• 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 33/54 having a particular shape
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/642 characterized by the shape
• CPC Class Codes: H05K 1/0203 Cooling of mounted components H05K1/0272 takes precedence
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]

Abstract

A light emitting die package is disclosed. The die package includes a substrate, a reflector plate, and a lens. The substrate is made from thermally conductive but electrically insulating material. 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. 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). The lens can be coated with any optical system of chemical that affects the performance of the device. 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). The reflector plate includes a reflective surface to direct light from the LED in a desired direction.

Claims

1. A light emitting die package comprising:

a substrate having traces for connecting to a light emitting diode assembly at a mounting pad;

a reflector plate coupled to said substrate and substantially surrounding the mounting pad; and

lens substantially covering the mounting pad.

2. The light emitting die package recited in claim 1 further comprising a light emitting diode (LED) mounted on said substrate and connected to the traces of said substrate.

3. The light emitting die package recited in claim 2 wherein the LED is encapsulated within optically clear polymer.

4. The light emitting die package recited in claim 1 wherein said substrate comprises electrically insulating material having high thermal conductivity.

5. The light emitting die package recited in claim 1 wherein said substrate comprises thermally conductive material.

6. The light emitting die package recited in claim 1 further comprising an external heat sink coupled to said substrate.

8. The light emitting die package recited in claim 1 wherein at least one trace extends from the mounting pad to a side of said substrate.

9. The light emitting die package recited in claim 1 wherein said substrate comprises flanges along at least one side for mechanically engaging said reflector plate.

10. The light emitting die package recited in claim 1 wherein said reflector plate substantially surrounds the mounting pad.

11. The light emitting die package recited in claim 1 wherein said reflector plate defines a reflection surface.

12. The light emitting die package recited in claim 1 wherein said reflector plate comprises material having high thermal conductivity.

13. The light emitting die package recited in claim 1 wherein said reflector plate comprises at least one leg mechanically engaging said substrate for increased thermal transfer.

14. The light emitting die package recited in claim 1 wherein said reflector plate is connected to an external heat sink to allow heat from the package to be dissipated.

15. The light emitting die package recited in claim 1 wherein said reflector plate comprises cooling fins for heat dissipation.

16. The light emitting die package recited in claim 1 wherein said lens comprises a recess adapted to receive optical chemicals.

17. The light emitting die package recited in claim 1 wherein said lens comprises luminescence converting phosphors.

18. The light emitting die package recited in claim 1 wherein said lens comprises diffusant.

19. The light emitting die package recited in claim 1 wherein said lens comprises a phosphor.

7. The light emitting die package recited in claim 7 wherein said substrate has a bottom side plated with metals for coupling with said external heat sink.

20. A semiconductor die package comprising:

a bottom heat sink having traces on a top surface thereof;

a semiconductor chip mounted on the top surface of said bottom heat sink, said semiconductor chip electrically connected to the traces of said bottom heat sink; and

a top heat sink mechanically coupled to said bottom heat sink.

21. The semiconductor die package recited in claim 20 further comprising a light emitting diode (LED) mounted on said substrate and connected to the traces of said substrate.

22. The semiconductor die package recited in claim 21 wherein the LED is encapsulated.

23. The semiconductor die package recited in claim 20 wherein said substrate comprises electrically insulating material having high thermal conductivity.

24. The semiconductor die package recited in claim 20 further comprising an external heat sink coupled to said substrate.

25. The semiconductor die package recited in claim 24 wherein said substrate has a bottom side with thermal contact pad for coupling with said external heat sink.

26. The semiconductor die package recited in claim 20 further comprising mounting pads proximal to said mounting pad, said mounting pads adapted to allow a light emitting diode to be mounted on said substrate.

27. The semiconductor die package recited in claim 20 wherein at least one trace extends from top surface of said substrate to a side of said substrate.

28. The semiconductor die package recited in claim 20 wherein said substrate defines flanges along at least one side for mechanically engaging said reflector plate.

29. The semiconductor die package recited in claim 20 wherein said reflector plate substantially surrounds the mounting pad.

30. The semiconductor die package recited in claim 20 wherein said reflector plate defines a reflection surface.

31. The semiconductor die package recited in claim 20 wherein said reflector plate comprises material having high thermal conductivity.

32. The semiconductor die package recited in claim 20 wherein said reflector plate comprises legs mechanically engaging said substrate for increased thermal contact area.

33. The semiconductor die package recited in claim 20 wherein said lens comprising material is selected from a group consisting of glass, quartz, and high temperature plastic.

34. The semiconductor die package recited in claim 20 wherein said lens comprises luminescence converting phosphors.

35. The semiconductor die package recited in claim 20 wherein said lens comprises optical diffusant.

36. The semiconductor die package recited in claim 20 wherein said lens comprises a phosphor.

37. The semiconductor die package recited in claim 20 wherein said lens is placed over and adheres to encapsulant.

38. The semiconductor die package recited in claim 37 wherein said encapsulant comprises elastic material.

39. The semiconductor die package recited in claim 20 wherein said lens comprises material selected from a group consisting of glass and quartz.

40. The semiconductor die package recited in claim 20 wherein said lens comprises high transparent plastic material.