High Performance LED Package

• US 20080173883A1
• Filed: 01/19/2007
• Published: 07/24/2008
• Est. Priority Date: 01/19/2007
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Bergmann, Michael J., Emerson, David T., Hussell, Christopher P.
• Granted Patent: US 7,968,900 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• 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 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A light emitting diode lamp is disclosed that includes a resin package that defines a recess in the shape of a solid polygon or another three-dimensional solid. The recess includes a floor, two side walls along the respective longer sides of the floor, and two end walls along the respective shorter sides of the floor. The two side walls define an angle therebetween greater than 3°, and the two end walls define an angle therebetween greater than 40°. A light emitting diode chip is positioned on the rectangular floor of the package.

Claims

1. A light emitting diode lamp comprising:

a resin package with an aspect ratio greater than 1;

1 that defines a recess in the shape of a three dimensional solid;

said recess comprising a floor with an aspect ratio greater than 1;

1, side walls along the respective longer sides of said floor, and end walls along the respective shorter sides of said floor;

said package defining a first plane bisecting said package along its long axis and a second plane bisecting said package along its narrow axis.

said recess having a geometry selected from the group consisting of (i) said side walls defining an angle therebetween and along said second plane greater than 3°

, (ii) said end walls defining an angle therebetween and along said first plane greater than 40°

, and (iii) combinations thereof, and

a light emitting diode chip on said floor of said package.

2. A light emitting diode according to claim 1 comprising curved end walls.

3. A light emitting diode according to claim 1 comprising curved side walls.

4. A light emitting diode according to claim 1 wherein:

the active portion of said light emitting diode is formed from the Group III nitride material system; and

said package further comprises electrical contacts between said floor and at least one outside surface of said package.

5. A light emitting diode lamp according to claim 1 wherein:

said diode emits in the blue portion of the visible spectrum;

said lamp further comprising;

a resin encapsulant in at least portions of said recess; and

a phosphor in said encapsulant that emits light in the yellow portion of the visible spectrum in response to blue light.

6. A light emitting diode lamp according to claim 5 wherein said phosphor comprises cesium-doped YAG and said package resin comprises polyamide.

7. A light emitting diode lamp according to claim 1 wherein said respective sidewalls and end walls are thick enough to prevent light from said chip from being transmitted through said walls and instead to be reflected from said walls.

8. A display comprising:

a light guide; and

a light emitting diode lamp according to claim 1 with the longer dimension of said diode lamp positioned adjacent said light guide with the display face of said light guide parallel to the predominant direction in which said diode lamp emits light.

9. A display according to claim 8 further comprising liquid crystals positioned to be illuminated by light emitted from said display face of said light guide.

10. A display according to claim 9 further comprising color filters positioned to be illuminated by light from said display face of said light guide.

11. A light emitting diode lamp comprising:

a resin package that defines a recess in the shape of a solid polygon;

said recess comprising a floor, side walls along the respective longer sides of said floor, and end walls along the respective shorter sides of said floor;

said recess having a geometry selected from the group consisting of (i) said side walls defining an angle therebetween greater than 3°

, (ii) said end walls defining an angle therebetween greater than 40°

, and (iii) combinations thereof; and

a light emitting diode chip on said floor of said package.

12. A light emitting diode according to claim 11 wherein:

the active portion of said light emitting diode is formed from the Group III nitride material system; and

said package further comprises electrical contacts between said floor and at least one outside surface of said package.

13. A light emitting diode lamp according to claim 11 wherein:

said diode emits in the blue portion of the visible spectrum;

said lamp further comprising;

a resin encapsulant in at least portions of said recess; and

a phosphor in said encapsulant that emits light in the yellow portion of the visible spectrum in response to blue light.

14. A light emitting diode lamp according to claim 13 wherein said phosphor comprises cesium-doped YAG and said package resin comprises polyamide.

15. A light emitting diode lamp according to claim 11 wherein said respective sidewalls and end walls are thick enough to prevent light from said chip from being transmitted through said walls and instead to be reflected from said walls.

16. A light emitting diode lamp comprising:

a resin package that defines a recess in the shape of a solid polygon;

said recess comprising a rectangular floor, two side walls along the respective longer sides of said rectangular floor, and two end walls along the respective shorter sides of said rectangular floor;

said two side walls defining an angle therebetween greater than 3°

; and

said two end walls defining an angle therebetween greater than 40°

; and

a light emitting diode chip on said rectangular floor of said package.

17. A light emitting diode lamp according to claim 16 wherein said package further comprises electrical contacts between said rectangular floor and at least one outside surface of said package.

18. A light emitting diode lamp according to claim 16 further comprising a resin encapsulant in at least portions of said recess.

19. A light emitting diode lamp according to claim 18 further comprising a phosphor in said encapsulant.

20. A light emitting diode lamp according to claim 19 wherein said diode emits in the blue portion of the visible spectrum and said phosphor emits light in the yellow portion of the visible spectrum in response to blue light.

21. A light emitting diode according to claim 19 wherein said phosphor comprises cesium-doped YAG.

22. A light emitting diode according to claim 16 wherein said package resin comprises polyamide.

23. A light emitting diode according to claim 16 wherein the active portion of said light emitting diode is formed from the Group III nitride material system.

24. A reflective structure for diode lamps comprising:

a package having at least one face that is substantially rectangular;

said package defining a recess in the form of a solid polygon having a floor parallel to said face, two side walls along the respective longer edges of said face, two end walls along the respective shorter edges of said face; and

a surface coplanar with said face;

said recess having a geometry selected from the group consisting of (i) said side walls defining an angle therebetween greater than 3°

, (ii) said end walls defining an angle therebetween greater than 40°

, and (iii) combinations thereof; and

electrical contacts to said floor.

25. A reflective structure according to claim 24 wherein said package comprises a polymer resin.

26. A reflective structure according to claim 24 wherein said polymer resin comprises a polyamide.

27. A reflective structure according to claim 25 wherein said polymer resin includes a white pigment.

28. A reflective structure according to claim 24 wherein said sidewalls define an angle of at least 60°

.

29. A reflective structure according to claim 24 wherein said sidewalls define an angle of at least 70°

.

30. A reflective structure according to claim 24 wherein said sidewalls define an angle of at least 80°

.

31. A reflective structure according to claim 24 wherein said end walls define an angle greater than 10°

.

32. A reflective structure according to claim 24 wherein said end walls define an angle greater than 20°

.

33. A reflective structure according to claim 24 wherein said end walls define an angle of at least 30°

.

34. A method of lighting a display comprising:

directing the light from a light emitting diode in a manner selected from the group consisting of (i) directing the light against two package walls that are separated by at least the dimensions of the diode and which walls form an angle between themselves of at least 3°

;

(ii) directing the light from the light emitting diode against two other package walls that are separated by at least the dimensions of the diode and which walls form an angle between themselves of at least 40°

; and

(iii) concurrently directing the light in combinations thereof; and

while

directing the light from the package walls to a light distributor that provides a light for a display.

35. A lighting method according to claim 34 comprising directing light in the blue portion of the visible spectrum from the light emitting diode.

36. A lighting method according to claim 35 comprising directing the blue light in the presence of a yellow-emitting phosphor.

37. A lighting method according to claim 34 comprising directing the light from the diode through a resin encapsulant lens.

38. A lighting method according to claim 34 comprising directing the light from the package walls to at least one edge of a substantially planar light distributor to thereby illuminate the distributor from the light emitting diode.

39. A method according to claim 38 comprising manipulating a liquid crystal display adjacent the light distributor while directing light from the light emitting diode to the distributor.