Power surface mount light emitting die package

• US 20070138497A1
• Filed: 02/08/2007
• Published: 06/21/2007
• Est. Priority Date: 05/27/2003
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Loh, Ban
• Granted Patent: US 7,775,685 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• 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 having 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 plate mechanically coupled to the substrate and substantially surrounding the mounting pad and LED, the reflector plate defining a reflection surface, and

a lens substantially covering the mounting pad and LED.

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 lens is placed over and adheres to the encapsulant so that the lens floats on the encapsulant.

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

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

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 5, wherein the substrate has a bottom side with a thermal contact pad for coupling with the external heat sink.

8. The semiconductor die package of claim 1, further comprising mounting pads proximal to the mounting pad, the mounting pads adapted to allow the LED to be mounted on the substrate.

9. 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.

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

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

12. The semiconductor die package of claim 1, wherein the reflector plate includes 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 includes luminescence converting phosphors.

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

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

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

20. A semiconductor die package, comprising:

a substrate,

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

a reflector plate coupled to the substrate and substantially surrounding the mounting pad and LED, the reflector plate having an opening there through,

a lens placed in the opening to substantially cover the mounting pad, LED and opening, and

an encapsulant covering the LED within at least part of the opening, wherein the lens adheres to the encapsulant so that the lens floats on the encapsulant within the opening.

21. The semiconductor die package of claim 20, wherein the reflector plate further defines a reflection surface.

22. The semiconductor die package of claim 20, wherein the reflector plate and substrate serve as corresponding top and bottom heat sinks for removing heat away from the LED during package operation.

23. A semiconductor die package, comprising:

a substrate having a top surface;

an insulating film covering at least a portion of the top surface of the substrate;

a pair of conductive traces on the insulating film and insulated from the top surface of the substrate by the insulating film, one of the traces of the pair including a trace portion that serves as a mounting pad for mounting a light emitting die (LED) thereon;

a reflector plate coupled to the substrate and substantially surrounding the LED and mounting pad, the reflector plate including an opening and a ledge within the opening, and

a lens coupled on the ledge of the reflector plate within the opening.

24. The semiconductor die package of claim 23, wherein the reflector plate further defines a reflection surface.

25. The semiconductor die package of claim 23, wherein

the lens substantially covers the mounting pad and LED,

the package further comprising an encapsulant covering the LED within at least part of the opening, the lens adhering to the encapsulant so that the lens floats on the encapsulant within the opening.

26. The semiconductor die package of claim 23, wherein the reflector plate and substrate serve as corresponding top and bottom heat sinks for removing heat away from the LED during package operation.