Power surface mount light emitting die package

• US 7,244,965 B2
• Filed: 10/22/2003
• Issued: 07/17/2007
• Est. Priority Date: 09/04/2002
• Status: Expired due to Term

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Andrews, Peter S., Loh, Ban P.
• Primary Examiner(s): Lee; Eugene
• Application Number:
  US10/692,351
• Publication Number:
  US 20040079957A1
• Time in Patent Office: 1,364 Days
• Field of Search: 257/95, 257/98, 257/99, 257/100, 257/699, 257/706, 257/707, 257/712, 257/E33.056
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• 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 2924/0102 Calcium [Ca]
• CPC Class Codes: H01L 2924/01025 Manganese [Mn]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/52 Encapsulations
• 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 33/62 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
• CPC Class Codes: H01L 33/641 characterized by the materials
• CPC Class Codes: H01L 33/642 characterized by the shape
• CPC Class Codes: H01L 33/647 the elements conducting electric current to or from the semiconductor body

Abstract

A light emitting die package is disclosed. The die package includes a substrate, a reflector plate, and a lens. The substrate may be made from thermally conductive but electrically insulating material or from a material that is both thermally and electrically conductive. In embodiments wherein the substrate is made from an electrically conductive material, the substrate further includes an electrically insulating, thermally conductive material formed on the electrically conductive material. The substrate has traces for connecting 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 substantially covers the mounting pad. 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 comprising an electrically and thermally conductive material and having a first surface;

a thermally conductive, electrically insulating film covering at least a portion of said first surface;

a first conductive element on said insulating film, said conductive element insulated from said substrate by said insulating film;

a second conductive element on said insulating film, said second conductive element spaced apart from said first conductive element and electrically insulated from said substrate by said insulating film wherein at least one of said first and second conductive elements comprises a mounting pad for mounting a light emitting die thereon;

a reflector plate coupled to said substrate and substantially surrounding the mounting pad, said reflector plate defining a reflection surface; and

a 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 first and second conductive elements.

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 first and second conductive elements comprise metal traces.

5. The light emitting die package recited in claim 1 wherein said substrate comprises a metal.

6. The light emitting die package recited in claim 5, wherein said substrate comprises a metal selected from the group consisting of copper and aluminum.

7. The light emitting die package recited in claim 5, wherein said substrate comprises a copper/aluminum alloy.

8. The light emitting die package recited in claim 1 wherein said insulating film comprises a ceramic polymer film.

9. The light emitting die package recited in claim 1, wherein said substrate comprises a second surface opposite said first surface, and further comprising at least one via hole through said substrate.

10. The light emitting die package recited in claim 9, wherein the surface of said via hole is coated with an insulating film coating.

11. The light emitting die package recited in claim 9 wherein said second surface of said substrate includes a thermally conductive insulating film on at least a portion of said second surface and wherein said package further comprises a third electrical lead on said second surface, said third electrical lead is insulated from said substrate by said thermally conductive insulating film and said third electrical lead is in electrical contact with said conductive trace through said via hole.

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

13. The light emitting die package recited in claim 12 wherein said substrate has a bottom side plated with metals for coupling with said external heat sink.

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

15. 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.

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

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

18. 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.

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

20. The light emitting die package recited in claim 1 wherein said lens comprises frequency shifting compounds.

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

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

23. A light emitting die package comprising:

a metal substrate having a first surface;

an electrically insulating film covering at least a portion of said first surface;

a first conductive trace on said insulating film, said conductive trace insulated from said substrate by said insulating film;

a mounting pad for mounting a light emitting device, said mounting pad electrically connected to said first conductive trace;

a reflector plate coupled to said substrate and substantially surrounding the mounting pad, said reflector plate defining a reflection surface; and

a lens substantially covering the mounting pad.