Light emission device

• US 20060152140A1
• Filed: 01/10/2005
• Published: 07/13/2006
• Est. Priority Date: 01/10/2005
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Brandes, George R.
• Granted Patent: US 7,564,180 B2
• Time in Patent Office: Days
• US Class Current: 313/503
• CPC Class Codes: C09K 11/586 with alkaline earth metals
• CPC Class Codes: C09K 11/623 with zinc or cadmium
• CPC Class Codes: C09K 11/7421 with alkaline earth metals
• CPC Class Codes: C09K 11/7702 with zinc or cadmium
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21Y 2113/17 forming a single encapsulated light source
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A light emission device, including at least two LED dies having differing spectral output from one another; and phosphor material including one or more phosphors, arranged to receive spectral output from at least one of the LED dies and to responsively emit a phosphor output, as a component of a spectral output of the light emission device. In a specific arrangement, the multiple LED dies and phosphor material are arranged to produce a white light output having a color temperature selected from among (i) color temperature in a range of from 1350° K to 1550° K, (ii) color temperature in a range of from 2400° K to 3550° K and (iii) color temperature in a range of from 4950° K to 6050° K.

Claims

1. A light emission device, comprising:

at least two LED dies having differing spectral output from one another; and

phosphor material including one or more phosphors, arranged to receive spectral output from at least one of the LED dies and to responsively emit a phosphor output as at least part of spectral output of the light emission device.

2. The light emission device of claim 1, wherein the phosphor material is arranged to receive spectral output from at least two LED dies.

3. The light emission device of claim 1, wherein the phosphor material is arranged to receive spectral output from all of the at least two LED dies.

4. The light emission device of claim 1, wherein the phosphor material includes at least two phosphors.

5. The light emission device of claim 1, including two LED dies.

6. The light emission device of claim 5, wherein the phosphor material includes two phosphors.

7. The light emission device of claim 1, including five LED dies.

8. The light emission device of claim 1, wherein the spectral output of the light emission device is a white light spectral output.

9. The light emission device of claim 1, wherein the spectral output of the light emission device is light other than white light.

10. The light emission device of claim 1, wherein the spectral output of the light emission device substantially matches an illumination spectrum of sunlight, candle light, or incandescent filament light.

11. The light emission device of claim 1, wherein the spectral output of the light emission device substantially matches an illumination spectrum of fire.

12. The light emission device of claim 1, wherein the spectral output of the light emission device is white light having a color temperature in one of the following white light color temperature regimes (A), (B) and (C):

(A) white light having a color temperature in a range of from 1350°

K to 1550°

K;

(B) white light having a color temperature in a range of from 2400°

K to 3550°

K;

(C) white light having a color temperature in a range of from 4950°

K to 6050°

K.

13. The light emission device of claim 12, wherein the white light comprises light having a color temperature in white light color regime (A).

14. The light emission device of claim 12, wherein the white light comprises light having a color temperature in white light color regime (B).

15. The light emission device of claim 12, wherein the white light comprises light having a color temperature in white light color regime (C).

16. The light emission device of claim 1, wherein the at least two LED dies and phosphor material are disposed in a unitary package.

17. The light emission device of claim 1, wherein the at least two LED dies are overlaid by the phosphor material.

18. The light emission device of claim 1, wherein the phosphor material is coated on the LED dies.

19. The light emission device of claim 1, wherein the phosphor material is conformally coated on the LED dies.

20. The light emission device of claim 1, wherein the phosphor material is coated on the LED dies, so that spectral output of the LED dies traverses a substantially constant thickness of the phosphor material over the LED dies.

21. The light emission device of claim 1, wherein the phosphor material is dispersed in a glass or polymeric composition.

22. The light emission device of claim 1, wherein the at least two LED dies include a blue LED die and a green LED die.

23. The light emission device of claim 22, wherein the phosphor material comprises a CaGa₂S₄:

Eu²⁺ phosphor and a ZnGa₂S₄;

Mn²⁺ phosphor.

24. The light emission device of claim 1, wherein the at least two LED dies include a red LED die and a blue LED die.

25. The light emission device of claim 24, wherein the phosphor material comprises a SrSCu+,Na phosphor and a CaSO₄:

Bi phosphor.

26. The light emission device of claim 1, wherein the phosphor material comprises a YAG material.

27. The light emission device of claim 1, wherein the at least two LED dies include an ultraviolet LED die and a blue LED die.

28. The light emission device of claim 27, wherein the phosphor material includes a CaMgSi₂O₆:

Eu²⁺,Mn²⁺ phosphor.

29. The light emission device of claim 1, wherein the at least two LED dies and phosphor material include a first LED die or phosphor having an aging profile including a degradation of light emission over its service life, and at least a second LED die or phosphor having an aging profile at least partially compensating said degradation of light emission of said first LED or phosphor.

30. The light emission device of claim 1, wherein the at least two LED dies includes dies differing from one another in die size.

31. The light emission device of claim 1, wherein the at least two LED dies and the phosphor material are in a unitary package, with the phosphor material including at least two phosphors in mixture with one another, wherein the phosphor material is deposited over the at least two LED dies in the unitary package.

32. The light emission device of claim 31, wherein the phosphor material comprises a glass or polymeric composition in which the at least two phosphors are dispersed.

47. The light emission device of claim 1, wherein LED dies and phosphor material are matched in aging character thereof to provide a predetermined character of spectral output over life of the device.

48. The light emission device of claim 47, wherein said predetermined character of spectral output includes a transition in color of spectral output at a predetermined time during said life of the device.

33. A method of generating light, comprising exciting at least two LED dies having differing spectral output from one another, to emit spectral outputs from each of said dies, and impinging the spectral output from at least one of said dies on phosphor material including one or more phosphors, to responsively emit a phosphor output as at least part of spectral output constituting said light.

34. The method of claim 33, wherein said light is a white light.

35. The method of claim 33, wherein said light is other than white light.

36. The method of claim 33, wherein the light substantially matches an illumination spectrum of sunlight, candle light, or incandescent filament light.

37. The method of claim 33, wherein the light substantially matches an illumination spectrum of fire.

38. The method of claim 33, wherein the light is white light having a color temperature in one of the following white light color temperature regimes (A), (B) and (C):

(A) white light having a color temperature in a range of from 1350°

K to 1550°

K;

(B) white light having a color temperature in a range of from 2400°

K to 3550°

K;

(C) white light having a color temperature in a range of from 4950°

K to 6050°

K.

39. The method of claim 38, wherein the white light comprises light having a color temperature in white light color regime (A).

40. The method of claim 38, wherein the white light comprises light having a color temperature in white light color regime (B).

41. The method of claim 38, wherein the white light comprises light having a color temperature in white light color regime (C).

42. The method of claim 33, wherein the at least two LED dies and phosphor material are disposed in a unitary package.

43. The method of claim 42, wherein the phosphor material overlies the at least two LED dies.

44. The method of claim 33, wherein the phosphor material is conformally coated on the LED dies.

45. The method of claim 33, wherein the phosphor material is coated on the LED dies, so that the spectral output of the LED dies traverses a substantially constant thickness of the phosphor material over the LED dies.

46. The method of claim 33, wherein the phosphor material comprises a YAG material.