Power surface mount light emitting die package

• US 7,775,685 B2
• Filed: 02/08/2007
• Issued: 08/17/2010
• Est. Priority Date: 05/27/2003
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Loh, Ban P.
• Primary Examiner(s): Alavi; Ali
• Application Number:
  US11/703,721
• Publication Number:
  US 20070138497A1
• Time in Patent Office: 1,286 Days
• Field of Search: 362/294, 362/84, 362/800, 257 98-100
• 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 semiconductor die package, comprising:

a substrate comprising conductive traces on a top surface thereof,

a light emitting diode (LED) mounted to the top surface of the substrate via a mounting pad, the mounting pad electrically connected to the conductive traces on the substrate top surface,

a reflector coupled to the substrate and substantially surrounding the mounting pad and LED, the reflector defining a reflection surface and the reflector comprising a ledge formed therein, and

a lens substantially covering the mounting pad and LED and being supported by the ledge of the reflector.

2. The semiconductor die package of claim 1, wherein the LED is encapsulated within an encapsulant.

3. The semiconductor die package of claim 2, wherein the encapsulant comprises an elastic material.

4. The semiconductor die package of claim 1, wherein the substrate comprises an electrically insulating material having high thermal conductivity.

5. The semiconductor die package of claim 1, wherein at least one trace extends from a top surface of the substrate to a side of the substrate.

6. The semiconductor die package of claim 1, further comprising an external heat sink coupled to the substrate.

7. The semiconductor die package of claim 6, wherein the substrate comprises a bottom side with a thermal contact pad for coupling with the external heat sink.

8. The semiconductor die package of claim 1, wherein the lens is composed of a high transparent plastic material.

9. The semiconductor die package of claim 1, wherein the reflector and substrate serve as corresponding top and bottom heat sinks for removing heat away from the LED during package operation.

10. The semiconductor die package of claim 1, wherein the substrate comprises flanges along at least one side thereof for mechanically engaging the reflector.

11. The semiconductor die package of claim 1, wherein the reflector is composed of a material having high thermal conductivity.

12. The semiconductor die package of claim 1, wherein the reflector comprises legs mechanically engaging the substrate for increased thermal contact area.

13. The semiconductor die package of claim 1, wherein the lens is composed of a material selected from a group consisting of glass, quartz, and a high temperature plastic material.

14. The semiconductor die package of claim 1, wherein the lens comprises luminescence converting phosphors.

15. The semiconductor die package of claim 1, wherein the lens comprises an optical diffusant.

16. The semiconductor die package of claim 1, wherein the lens comprises a phosphor.

17. The semiconductor die package of claim 1, wherein the lens comprises a material selected from a group consisting of glass and quartz.

18. The semiconductor die package of claim 1, wherein the reflector surrounds the mounting pad while leaving other portions of the top surface of the substrate and portions of the conductive traces exposed with the reflector partially defining an optical cavity.

19. A semiconductor die package, comprising:

a substrate comprising conductive traces on a top surface thereof,

a light emitting diode (LED) mounted to the top surface of the substrate via a mounting pad, the mounting pad electrically connected to the conductive traces on the substrate top surface,

a reflector coupled to the substrate and substantially surrounding the mounting pad and LED, the reflector defining a reflection surface and the LED being encapsulated within an encapsulant, and

a lens substantially covering the mounting pad and LED, wherein the lens is placed over and adheres to the encapsulant so that the lens floats on the encapsulant.

20. The semiconductor die package of claim 19, wherein the reflector surrounds the mounting pad while leaving other portions of the top surface of the substrate and portions of the conductive traces exposed with the reflector partially defining an optical cavity.