Troffer-Style Fixture

• US 20120051041A1
• Filed: 08/31/2010
• Published: 03/01/2012
• Est. Priority Date: 08/31/2010
• Status: Active Grant

• Current Assignee: IDEAL Industries Lighting, LLC (Ideal Industries Incorporated), Ideal Industries, LLC (Ideal Industries Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Pickard, Paul, Negley, Gerald, Trott, Gary David, Edmond, Mark, Lu, Dong, Nguyen, Nick
• Granted Patent: US 10,883,702 B2
• Time in Patent Office: Days
• US Class Current: 362/231
• CPC Class Codes: F21S 8/026 intended to be recessed in a ceiling or like overhead structure, e.g. suspended ceiling
• CPC Class Codes: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: F21V 29/745 the fins or blades being planar and inclined with respect to the joining surface from which the fins or blades extend
• CPC Class Codes: F21V 29/75 with fins or blades having different shapes, thicknesses or spacing
• CPC Class Codes: F21V 7/0008 providing for indirect lighting
• CPC Class Codes: F21V 7/24 characterised by the material
• CPC Class Codes: F21V 7/30 the coatings comprising photoluminescent substances
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

An indirect troffer. Embodiments of the present invention provide a troffer-style fixture that is particularly well-suited for use with solid state light sources, such as LEDs. The troffer comprises a light engine unit that is surrounded on its perimeter by a reflective pan. A back reflector defines a reflective interior surface of the light engine. To facilitate thermal dissipation, a heat sink is disposed proximate to the back reflector. A portion of the heat sink is exposed to the ambient room environment while another portion functions as a mount surface for the light sources that faces the back reflector. One or more light sources disposed along the heat sink mount surface emit light into an interior cavity where it can be mixed and/or shaped prior to emission. In some embodiments, one or more lens plates extend from the heat sink out to the back reflector.

Claims

1. A light engine unit, comprising:

a body comprising a back reflector on a surface of said body; and

a heat sink mounted proximate to said back reflector, said heat sink comprising a mount surface that faces toward said back reflector, said mount surface capable of having at least one light emitter mounted thereto, the region between said heat sink and said body defining an interior cavity.

8. The light engine unit of claim 1, said back reflector comprising a diffuse white reflector.

9. The light engine unit of claim 1, said back reflector comprising a microcellular polyethylene terephthalate (MCPET) material.

10. The light engine unit of claim 1, said back reflector comprising a specular reflective material.

11. The light engine unit of claim 1, wherein said back reflector is partially specular reflective and partially diffuse reflective.

12. The light engine unit of claim 1, wherein said back reflector is greater than 97% reflective.

13. The light engine unit of claim 1, wherein said back reflector is greater than 95% reflective.

14. The light engine unit of claim 1, wherein said back reflector is greater than 93% reflective.

15. The light engine unit of claim 1, wherein a portion of said heat sink opposite said mount surface is exposed to the ambient outside of said cavity.

16. The light engine unit of claim 1, said mount surface comprising a flat area facing said back reflector.

17. The light engine unit of claim 1, said mount surface comprising two flat areas each facing at an angle toward different portions of said back reflector.

18. The light engine unit of claim 1, further comprising at least one light strip disposed on said mount surface such that said at least one light strip faces said back reflector.

19. The light engine unit of claim 1, further comprising multiple light strips disposed on said mount surface such that said light strips face different portions of said back reflector.

20. The light engine unit of claim 1, further comprising lens plates arranged on each side of said heat sink and extending from said heat sink to said back reflector such that said back reflector, said heat sink, and said lens plates define said interior cavity.

21. The light engine unit of claim 20, said lens plates comprising a diffusive film inlay.

22. The light engine unit of claim 20, said lens plates comprising a diffusive film integral to said lens plates.

23. The light engine unit of claim 20, said lens plates having a diffractive pattern.

24. The light engine unit of claim 20, said lens plates having a random or regular geometric pattern.

25. The light engine unit of claim 20, said lens plates comprising a diffusive volumetric material.

26. The light engine unit of claim 20, said lens plates comprising beam-shaping features.

27. The light engine unit of claim 20, said lens plates comprising microlens structures.

28. The light engine unit of claim 1, further comprising a plurality of light emitting diodes (LEDs) on said mount surface.

29. The light engine unit of claim 28, wherein said LEDs are evenly spaced from one another along at least a portion of said mount surface in the longitudinal direction.

30. The light engine unit of claim 1, further comprising at least one cluster of LEDs on said mount surface.

31. The light engine unit of claim 30, said cluster comprising a combination of LEDs that emit white light during operation.

32. The light engine unit of claim 30, each of said clusters comprising two blue-shifted-yellow LEDs and one red LED that combine to emit white light during operation.

33. The light engine unit of claim 30, each of said clusters comprising three blue-shifted-yellow LEDs and one red LED that combine to emit white light during operation.

34. The light engine unit of claim 30, each of said clusters comprising two blue-shifted-yellow LEDs and two red LEDs that combine to emit white light during operation.

35. The light engine unit of claim 30, wherein a longitudinal distance between consecutive clusters is uniform.

36. The light engine unit of claim 30, wherein a longitudinal distance between consecutive LEDs within each of said clusters is uniform.

37. The light engine unit of claim 36, wherein said longitudinal distance between consecutive LEDs is not more than approximately 8 mm.

38. The light engine unit of claim 1, further comprising transmissive end caps disposed at both ends of said body.

39. A lighting troffer, comprising:

a pan structure comprising an inner reflective surface;

a body mounted inside said pan structure such that said inner reflective surface surrounds said body;

a back reflector on a surface of said body;

an elongated heat sink mounted proximate to said back reflector and running longitudinally along a central region of said body;

a plurality of light emitting diodes (LEDs) disposed on a mount surface of said heat sink that faces toward said back reflector; and

lens plates arranged on each side of said heat sink and extending from said heat sink to said back reflector such that said back reflector, said heat sink, and said lens plates define an interior cavity.

40. The lighting troffer of claim 39, wherein said back reflector comprises reflective side regions on either side of said central region such that said back reflector is symmetrical about a longitudinal axis.

41. The lighting troffer of claim 40, wherein said reflective side regions are parabolic.

42. The lighting troffer of claim 40, wherein said reflective side regions are flat.

43. The lighting troffer of claim 40, wherein said reflective side regions are corrugated.

44. The lighting troffer of claim 39, said central region comprising a flat center.

45. The lighting troffer of claim 39, said central region having a shape defined by a vertex.

46. The lighting troffer of claim 39, said back reflector comprising a diffuse white reflector.

47. The lighting troffer of claim 39, said back reflector comprising a microcellular polyethylene terephthalate (MCPET) material.

48. The lighting troffer of claim 39, said back reflector comprising a specular reflective material.

49. The lighting troffer of claim 39, wherein said back reflector is partially specular reflective and partially diffuse reflective.

50. The lighting troffer of claim 39, wherein said back reflector is greater than 97% reflective.

51. The lighting troffer of claim 39, wherein a portion of said heat sink opposite said mount surface is exposed to the ambient outside of said cavity.

52. The lighting troffer of claim 39, said mount surface comprising a flat area facing said back reflector.

53. The lighting troffer of claim 39, said mount surface comprising two flat areas each facing at an angle toward different portions of said back reflector.

54. The lighting troffer of claim 39, wherein said LEDs are on at least one light strip disposed on said mount surface such that said at least one light strip faces said back reflector.

55. The lighting troffer of claim 39, wherein said LEDs are on multiple light strips disposed on said mount surface such that said light strips face different portions of said back reflector.

56. The lighting troffer of claim 39, said lens plates comprising a diffusive film inlay.

57. The lighting troffer of claim 39, said lens plates comprising a diffusive film integral to said lens plates.

58. The lighting troffer of claim 39, said lens plates having a diffractive pattern.

59. The lighting troffer of claim 39, said lens plates having a random or regular geometric pattern.

60. The lighting troffer of claim 39, said lens plates comprising a diffusive volumetric material.

61. The lighting troffer of claim 39, said lens plates comprising beam-shaping features.

62. The lighting troffer of claim 39, said lens plates comprising microlens structures.

63. The lighting troffer of claim 39, said plurality of LEDs comprising at least one cluster of blue-shifted-yellow LEDs and at least one cluster red LEDs.

64. The lighting troffer of claim 39, further comprising translucent end caps disposed at both ends of said body and orthogonal to said body.

65. The lighting troffer of claim 39, said plurality of LEDs emitting a combination of wavelengths that appears as white light.

66. The lighting troffer of claim 39, further comprising transmissive end caps over the longitudinal ends of said interior cavity.

2. The light engine unit of claim 1, wherein said back reflector comprises:

a reflective center region that runs longitudinally down the center of said body; and

reflective side regions on either side of said center region such that said back reflector is symmetrical about a longitudinal axis.

3. The light engine unit of claim 2, wherein said reflective side regions are parabolic.

4. The light engine unit of claim 2, wherein said reflective side regions are flat.

5. The light engine unit of claim 2, wherein said reflective side regions are corrugated.

6. The light engine unit of claim 2, said center region comprising a flat center.

7. The light engine unit of claim 2, said center region having a shape defined by a vertex.

67. The lighting troffer of claim 39, wherein said pan structure further comprises contoured end sections where the pan structure abuts the longitudinal ends of said light engine.

68. The lighting unit of claim 66, further comprising a first lens plate that extends from the edge of said heat sink to said first side region of said back reflector.

69. The lighting unit of claim 66, wherein said light emitters are angled to face said first side region of said back reflector.

70. The lighting unit of claim 66, wherein said light emitters combine to emit white light during operation.

71. The lighting unit of claim 66, said back reflector comprising a diffuse white reflector.

72. The lighting unit of claim 66, wherein said back reflector is asymmetrical about a longitudinal axis running through said heat sink.

66-1. A lighting unit, comprising:

a back reflector, said back reflector comprising;

a spine region that runs longitudinally down said back reflector; and

a first side region on a side of said spine region;

a heat sink mounted proximate to said back reflector, said heat sink comprising a mount surface that faces toward said back reflector, the region between said heat sink and said body defining an interior cavity; and

a plurality of light emitters disposed on said mount surface and aimed to emit light toward said back reflector.

67-2. The lighting unit of claim 66, said back reflector further comprising a second side region on the side of said spine region opposite said first side region, wherein said first and second side regions define an asymmetrical longitudinal cross-section.

73. A light fixture, comprising:

a body comprising a back reflector on a surface of said body; and

an elongated mount structure proximate to said back reflector and running along a length of said back reflector, said mount structure comprising an elongated mount surface that faces toward said back reflector, said mount surface capable of having at least one light emitter mounted thereto, the region between said mount structure and said body defining an interior cavity.

74. A light unit, comprising:

an elongated light source comprising a major axis, a minor axis, a first face configured to emit light, an opposing second face, and a plurality of light emitting diodes (LEDs) mounted on said first face;

a back reflector comprising subregions symmetrically shaped about the major axis of said elongated light source, said first face of said elongated light source facing said back reflector; and

a lens plate extending from said elongated light source.

75. The light unit of claim 74, wherein said LEDs comprise blue LEDs.

76. The light unit of claim 74, wherein said back reflector comprises:

a reflective center region that runs along said major axis of said elongated light source; and

reflective side regions on either side of said center region such that said back reflector is symmetrical about said center region.

77. The light unit of claim 74, wherein said back reflector comprises a major axis and a minor axis aligned with said major axis and minor axis of said elongated light source.

78. A light fixture, comprising:

at least one light source; and

a recessed lay-in fixture structure having a room-side area profile of at least approximately 4 ft², said at least one light source housed within said fixture structure;

wherein during operation of said at least one light source said fixture structure outputs light at no less than 88% total optical efficiency with a maximum surface luminance of not greater than 32 lm/in² and a luminance gradient of not more than 5;

1.

79. The light fixture of claim 78, wherein said luminance gradient is not more than 3:

1.

80. The light fixture of claim 78, wherein said maximum surface luminance is not greater than 24 lm/in².

81. The light fixture of claim 80, wherein said luminance gradient is not more than 3:

1.