Solid state white light emitter and display using same

• US 8,502,247 B2
• Filed: 06/01/2008
• Issued: 08/06/2013
• Est. Priority Date: 03/26/1996
• Status: Expired due to Fees

• Current Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Tischler, Michael A., Baretz, Bruce H.
• Primary Examiner(s): Such, Matthew W
• Assistant Examiner(s): Kalam, Abul
• Application Number:
  US12/131,118
• Publication Number:
  US 20080224597A1
• Time in Patent Office: 1,892 Days
• Field of Search: 257/98
• US Class Current: 257/98
• CPC Class Codes: G09F 13/04 Signs, boards or panels, illuminated from behind the insignia
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48139 with an intermediate bond, e.g. continuous wire daisy chain
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• 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 2924/00014 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 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: Y02E 10/52 PV systems with concentrators

Abstract

A light emitting assembly comprising a solid state device coupleable with a power supply constructed and arranged to power the solid state device to emit from the solid state device a first, relatively shorter wavelength radiation, and a down-converting luminophoric medium arranged in receiving relationship to said first, relatively shorter wavelength radiation, and which in exposure to said first, relatively shorter wavelength radiation, is excited to responsively emit second, relatively longer wavelength radiation. In a specific embodiment, monochromatic blue or UV light output from a light-emitting diode is down-converted to white light by packaging the diode with fluorescent organic and/or inorganic fluorescers and phosphors in a polymeric matrix.

Claims

1. A light emitting device, comprising:

multiple LEDs each configured to emit blue light; and

a same luminophoric medium configured to interact with emitted blue light from the multiple LEDs to produce down-converted light,

wherein the emitted blue light from the multiple LEDs and said down-converted light produce a white light output.

2. A light emitting device according to claim 1, comprising:

each of said multiple LEDs comprising an LED including an emitting face configured to emit blue light; and

wherein the luminophoric medium is in contact with each said LED.

3. The light emitting device of claim 2, wherein the luminophoric medium is in contact with the emitting face of each said LED.

4. The light emitting device of claim 2, wherein the luminophoric medium is in contact with an edge of the emitting face of each said LED.

5. The light emitting device of claim 2, wherein the LEDs are electrically coupled with one another.

6. The light emitting device of claim 2, wherein each said LED includes a rear face, and side surface between said emitting face and said rear face, and said luminophoric medium is in contact with said side surface of each said LED.

7. The light emitting device of claim 1, wherein the luminophoric medium comprises an inorganic luminophor.

8. The light emitting device of claim 7, wherein the inorganic luminophor is dispersed on or in a housing member.

9. The light emitting device of claim 7, wherein the inorganic luminophor is dispersed in a film on an interior surface of a housing member.

10. The light emitting device of claim 7, wherein the inorganic luminophor is dispersed in a light transmissive polymer or glass.

11. The light emitting device of claim 7, wherein the inorganic luminophor is dispersed as an exterior film on a light transmissive polymer or glass.

12. The light emitting device of claim 7, wherein the inorganic luminophor is dispersed as an interior film on a light transmissive polymer or glass.

13. The light emitting device of claim 8, wherein said housing member comprises glass.

14. The light emitting device of claim 8, wherein said housing member comprises a light transmissive polymer.

15. The light emitting device of claim 8, wherein said housing member is arranged to provide light output from substantially the entire area of the housing member.

16. The light emitting device of claim 7, wherein the inorganic luminophor is dispersed in a polymer.

17. The light emitting device of claim 11, wherein said device comprises a housing member formed of said polymer.

18. The light emitting device of claim 17, wherein said housing member is arranged to provide light output from the entire area of the housing.

19. The light emitting device of claim 7, wherein said device comprises a housing member, and the inorganic luminophor is in a coating on a surface of the housing member.

20. The light emitting device of claim 19, wherein said coating is on an interior surface of the housing member.

21. The light emitting device of claim 19, wherein said coating is on an exterior surface of the housing member.

22. The light emitting device of claim 7, wherein said device comprises an enclosure, and the enclosure is filled with luminophoric medium.

23. The light emitting device of claim 7, wherein said device comprises a wall, and said luminophoric medium is on or in said wall.

24. The light emitting device of claim 7, wherein said luminophoric medium is in spaced relationship to the LEDs.

25. The light emitting device of claim 7, wherein said device comprises an enclosure, and said luminophoric medium is in an interior volume of said enclosure.

26. The light emitting device of claim 7, wherein said luminophoric medium is in contact with a sidewall of each of said LEDs.

27. The light emitting device of claim 7, wherein light output of said device includes red and yellow radiation emission.

28. The light emitting device of claim 7, wherein light output of said device includes red, green and blue radiation emission.

29. The light emitting device of claim 7, wherein light output of said device includes red, green, blue and yellow radiation emission.

30. The light emitting device of claim 7, wherein each individual component of said luminophoric medium has a concentration of from 10⁻

3 to 10 mole percent of said medium.

31. The light emitting device of claim 7, wherein each of said LEDs comprises material selected from the group consisting of gallium nitride and its alloys.

32. The light emitting device of claim 31, wherein each of said LEDs comprises gallium nitride.

33. The light emitting device of claim 31, wherein each of said LEDs comprises gallium nitride alloy.

34. The light emitting device of claim 31, wherein each of said LEDs comprises gallium nitride alloy selected from the group consisting of aluminum gallium nitride, aluminum gallium indium nitride, and indium gallium nitride.

68. The light emitting device of any one of claims 35, 40, 53, 54, 58, 1, and 59, wherein the luminophoric medium comprises fluorescer.

35. A light emitting device, comprising:

a housing;

an array of LEDs in said housing, each of said LEDs including an emitting face configured to emit blue light; and

a luminophoric medium in the housing and in contact with a light-transmissive wall member of the housing, interactive with emitted blue light from the LEDs to produce down-converted light, wherein the emitted blue light from the LEDs and down-converted light produce a white light output.

36. The light emitting device of claim 35, further comprising a polymeric material within said housing, wherein the luminophoric medium comprises phosphor material in said polymeric material.

37. The light emitting device of claim 36, wherein the polymeric material overlies the LEDs.

38. The light emitting device of claim 36, wherein the polymeric material containing the phosphor material is contiguously arranged about the LEDs in said housing.

39. The light emitting device of claim 36, wherein said polymeric material comprises an epoxy.

40. A light emitting device, comprising:

an array of LEDs, wherein each LED is configured to emit blue light; and

a same luminophoric medium configured to interact with emitted blue light from the LEDs in said array to produce down-converted light,

wherein the emitted blue light from the LEDs in said array and said down-converted light produce a white light output.

41. The light emitting device of claim 40, wherein the luminophoric medium is contiguous to the array of LEDs.

42. The light emitting device of claim 40, wherein the luminophoric medium is in spaced relationship to the array of LEDs.

43. The light emitting device of claim 40, wherein the luminophoric medium comprises phosphor contiguous to the array of LEDs.

44. The light emitting device of claim 40, wherein the luminophoric medium comprises phosphor in spaced relationship to the array of LEDs.

45. The light emitting device of claim 40, wherein the luminophoric medium comprises a mixture of phosphor components.

46. The light emitting device of claim 45, wherein the mixture of phosphor components comprises red and yellow phosphors.

47. The light emitting device of claim 40, wherein the luminophoric medium comprises a homogeneous composition.

48. The light emitting device of claim 40, wherein the LEDs comprise gallium nitride alloy LEDs.

49. The light emitting device of claim 48, wherein said gallium nitride alloy LEDs comprise gallium nitride alloy selected from the group consisting of:

aluminum gallium indium nitride;

aluminum gallium nitride;

indium gallium nitride; and

gallium nitride.

50. The light emitting device of claim 40, wherein the LEDs comprise gallium nitride LEDs.

51. The light emitting device of claim 40, wherein the luminophoric medium comprises polymer.

52. The light emitting device of claim 40, wherein the array of LEDs is electrically connected to an illumination output controller.

53. A light emitting device, comprising:

an array of LEDs, wherein each LED is adapted for emitting blue light;

a luminophoric medium comprising at least one of red, yellow and green emissive centers,

wherein the luminophoric medium is interactive with blue light from the LEDs to produce down-converted light, and the blue light and down-converted light produce a white light output, and wherein the array of LEDs is in a housing.

54. A light emitting device, comprising:

an array of LEDs, wherein each of said LEDs is configured to emit blue light; and

a same luminophoric medium configured to interact with emitted blue light from the LEDs in said array to produce down-converted light, said luminophoric medium comprising multiple materials,

wherein the emitted blue light from the LEDs in said array and said down-converted light produce a white light output, and wherein the array of LEDs is in a housing.

55. A light emitting device, comprising:

an array of LEDs, wherein each LED is configured to emit blue light;

a luminophoric medium interactive with emitted blue light from the LED to produce down-converted light,

wherein the luminophoric medium includes at least one phosphor doped with cerium or europium, and

wherein the emitted blue light from the LED and down-converted light produce a white light output, and wherein the array of LEDs is in a housing.

56. A white light emitting LED device including an array of LEDs, each LED of said array of LEDs emitting blue light and a luminophoric medium including phosphors, interactive with emitted blue light from the LED to produce down-converted light, wherein the luminophoric medium includes at least one of red and yellow emissive centers, wherein the emitted blue light from the LEDs and the down-converted light produce a white light output, and wherein the array of LEDs is in a housing.

57. The light emitting device of claim 56, wherein the luminophoric medium comprises red and yellow emissive centers.

58. A light emitting device comprising:

an array of LEDs, each said LED configured to emit blue light;

a luminophoric medium interactive with emitted blue light from the LEDs, said luminophoric medium being in contact with the LEDs, and including a red emissive center, interactive with emitted blue light from the LEDs to produce down-converted light, wherein the emitted blue light from the LEDs and down-converted light produce a white light output, and wherein the array of LEDs is in a housing.

59. A light emitting device, comprising:

a multiplicity of LEDs, wherein each LED is configured to emit blue light; and

a luminophoric medium configured to interact with emitted blue light from at least some of the LEDs in said multiplicity of LEDs, to produce down-converted light,

wherein the luminophoric medium is contiguous to the multiplicity of LEDs, and wherein said emitted blue light and down-converted light produce a white light output.

60. The light emitting device of claim 59, wherein the luminophoric medium comprises a mixture of phosphor components.

61. The light emitting device of claim 60, wherein the mixture of phosphor components comprises red and yellow phosphors.

62. The light emitting device of claim 59, wherein the luminophoric medium comprises a homogeneous composition.

63. The light emitting device of claim 59, wherein the multiplicity of LEDs comprise LEDs in a regular pattern.

64. The light emitting device of claim 59, wherein the LEDs comprise gallium nitride alloy LEDs.

65. The light emitting device of claim 64, wherein said gallium nitride alloy LEDs comprise gallium nitride alloy selected from the group consisting of:

aluminum gallium indium nitride;

aluminum gallium nitride;

indium gallium nitride; and

gallium nitride.

66. The light emitting device of claim 59, wherein the LEDs comprise gallium nitride LEDs.

67. The light emitting device of claim 59, wherein the luminophoric medium comprises polymer.