ENHANCED COLOR RENDERING INDEX EMITTER THROUGH PHOSPHOR SEPARATION

• US 20110228514A1
• Filed: 02/16/2011
• Published: 09/22/2011
• Est. Priority Date: 03/03/2010
• Status: Active Grant

• Current Assignee: IDEAL Industries Lighting, LLC (Ideal Industries Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: LeToquin, Ronan, Negley, Gerald, Ibbetson, James, Keller, Bernd, TONG, TAO
• Granted Patent: US 9,275,979 B2
• Time in Patent Office: Days
• US Class Current: 362/84
• CPC Class Codes: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 3/02 characterised by the shape
• CPC Class Codes: F21V 3/12 the coatings comprising photoluminescent substances
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

LED packages, and LED lamps and bulbs, are disclosed that are arranged to minimize the CRI and efficiency losses resulting from the overlap of conversion material emission and excitation spectrum. In different devices having conversion materials with this overlap, the present invention arranges the conversion materials to reduce the likelihood that re-emitted light from a first conversion materials will encounter the second conversion material to minimize the risk of re-absorption. In some embodiments this risk is minimized by different arrangements where there is separation between the two phosphors. In some embodiments this separation results less than 50% of re-emitted light from the one phosphor passing into the phosphor where it risks re-absorption.

Claims

1. A solid state lamp, comprising:

a light emitting diode (LED);

a first conversion material;

a second conversion material spaced from said first conversion material with light from said LED passing through said second conversion material, wherein said second conversion material wavelength converts and re-emits at least some of said LED light.

2. The lamp of claim 1, wherein light from said LED passes through said first conversion material wherein at least some of the light from LED is wavelength converted and re-emitted.

3. The lamp of claim 1, wherein said first conversion material has an excitation spectrum that overlaps with the re-emission spectrum of said second conversion material.

4. The lamp of claim 1, wherein said first and second conversion materials comprise phosphors.

5. The lamp of claim 1, wherein said second conversion material is over said first conversion material.

6. The lamp of claim 1, wherein said second conversion material comprises a dome over said first conversion material.

7. The lamp of claim 1, wherein the emission spectrum of said first conversion material does not overlap the excitation spectrum of said second conversion material.

8. The lamp of claim 1, wherein said first conversion material absorbs light from said LED and re-emits red light.

9. The lamp of claim 1, wherein said second conversion material absorbs light from said LED and re-emits yellow or green light.

10. The lamp of claim 1, further comprising an optical cavity.

11. The lamp of claim 1, wherein less than 50% of the light re-emitted from said second conversion material passes into said first conversion material.

12. The lamp of claim 1, wherein less than 25% of the light re-emitted from said second conversion material passes into said first conversion material.

13. The lamp of claim 1, emitting a white light combination or light from at least two of the sources comprising said LED, said first conversion material and said second conversion material.

14. The lamp of claim 1, wherein said second phosphor is in a globe over said light emitting diode.

15. The lamp of claim 14, further comprising a diffuser over said globe.

16. The lamp of claim 1, wherein said lamp emits light that having an emission pattern that is compliant with Energy Star standards.

17. The lamp of claim 1, sized to fit an A19 size profile.

18. The lamp of claim 1, wherein said second phosphor is planar.

19. The lamp of claim 1, further comprising a planar diffuser.

20. A solid state lamp, comprising:

a plurality of light emitting diodes (LEDs);

a red phosphor on at least one of said LEDs with light from said at least one of said LEDs passing through said red phosphor; and

a yellow or green phosphor separated from and over said LEDs, light from said LEDs passing through said yellow or green phosphor.

21. The lamp of claim 20, wherein said at least one of said plurality of LEDs emits blue light.

22. The lamp of claim 20, wherein at least one of said plurality of LEDs is uncoated by said red phosphor.

23. The lamp of claim 22, wherein said at least one uncoated LED emits blue light.

24. The lamp of claim 20, wherein said red phosphor absorbs some light from its one of said plurality of LEDs, and re-emits at least some red light.

25. The lamp of claim 20, wherein said yellow or green phosphor absorbs light from said LEDs and re-emits yellow or green light, respectively.

26. The lamp of claim 20, wherein said red phosphor has an excitation spectrum that overlaps with the emission spectrum of said yellow or green phosphor.

27. The lamp of claim 20, wherein said red phosphor comprises a conformal coat over its one of said plurality of LEDs.

28. The lamp of claim 20, wherein said yellow or green phosphor is over said red phosphor.

29. The lamp of claim 20, wherein said yellow or green phosphor comprises a dome over said red phosphor.

30. The lamp of claim 20, further comprising an optical cavity.

31. The lamp of claim 20, wherein less than 50% of the light re-emitted from said yellow or green phosphor passes into said red phosphor.

32. The lamp of claim 20, wherein less than 10% of the light re-emitted from said yellow or green phosphor passes into said red phosphor.

33. The lamp of claim 20, emitting a white light combination of light from at least two of said LED, said red phosphor, and said yellow or green phosphor.

34. The lamp of claim 20, emitting light with an emission pattern that is Energy Star compliant.

35. The lamp of claim 20, sized to fit an A19 size profile.

36. A solid state lamp, comprising:

a light emitting diode (LED) having a first phosphor coating absorbing some of the light emitted from said LED and re-emitting a different wavelength of light; and

a second phosphor spaced from said first phosphor with light from said LED passing through said second phosphor, said second phosphor absorbing at least some of said LED light and re-emitting a respective different wavelength of light, wherein the emission spectrum of said light re-emitted from said second phosphor overlaps the excitation spectrum of said first phosphor, and wherein the majority of light from said second phosphor does not encounter said first phosphor.

37. The lamp of claim 36, wherein said second phosphor is over said first phosphor.

38. The lamp of claim 36, wherein said second phosphor comprises a dome over said first phosphor.

39. The lamp of claim 36, wherein the emission spectrum of said first phosphor does not overlap the excitation spectrum of said second phosphor.

40. The lamp of claim 36, wherein the LED emits blue light.

41. The lamp of claim 36, wherein said first phosphor absorbs light from said LED and re-emits red light.

42. The lamp of claim 36, wherein said second phosphor absorbs light from said LED and re-emits yellow or green light.

43. The lamp of claim 36, wherein said first phosphor comprises a red phosphor and said second phosphor comprise a yellow or green phosphor, said red phosphor having an excitation spectrum that at least partially overlaps with the emission spectrum of said yellow or green phosphor.

44. The lamp of claim 36, further comprising an optical cavity.

45. The lamp of claim 36, wherein less than 50% of the light re-emitted from said second phosphor passes into said first phosphor.

46. The lamp of claim 36, wherein less than 10% of the light re-emitted from said second phosphor passes into said first phosphor.

47. The lamp of claim 36, emitting a white light combination or light from at least two of said LED, said first phosphor and said second phosphor.

48. The lamp of claim 36, emitting light with an emission pattern that is Energy Star compliant.

49. The lamp of claim 36, sized to fit an A19 size profile.