NON-UNIFORM DIFFUSER TO SCATTER LIGHT INTO UNIFORM EMISSION PATTERN

• US 20110216523A1
• Filed: 10/08/2010
• Published: 09/08/2011
• 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, Van De Ven, Antony, Youmans, Mark, Yuan, Zongjie, Guschl, Peter, Lowes, Theodore, TONG, TAO, Negley, Gerald, Keller, Bernd, Tarsa, Eric, Medendorp, Nicholas W. JR.
• Granted Patent: US 9,310,030 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 9/60 Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
• 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: F21K 9/65 specially adapted for changing the characteristics or the distribution of the light, e.g. by adjustment of parts
• CPC Class Codes: F21V 29/505 of reflectors
• CPC Class Codes: F21V 3/12 the coatings comprising photoluminescent substances
• CPC Class Codes: F21V 5/002 using microoptical elements for redirecting or diffusing light
• CPC Class Codes: F21V 5/10 comprising photoluminescent material
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 2924/00014 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 2924/181 Encapsulation

Abstract

A lighting device comprising a light source and a diffuser spaced from the light source. The lighting device further comprises a wavelength conversion material disposed between the light source and the diffuser and spaced from the light source and the diffuser, wherein the diffuser is shaped such that there are different distances between the diffuser and said conversion material at different emission angles. In other embodiments the diffuser includes areas with different diffusing characteristics. Some lamps are arranged to meet A19 and Energy Star lighting standards.

Claims

1. A lamp, comprising:

a solid state light source emitting a substantially forward emission pattern; and

a diffuser arranged to alter said forward emission pattern so that said lamp emits a emission pattern having greater uniformity than said forward emission pattern.

2. The lamp of claim 1, wherein said substantially forward emission pattern comprises a substantially Lambertian emission pattern.

3. The lamp of claim 1, wherein said light source is substantially planar

4. The lamp of claim 1, wherein said substantially uniform emission pattern is substantially omnidirectional.

5. The lamp of claim 1, wherein said diffuser has varying scattering properties over its surface.

6. The lamp of claim 1, wherein said diffuser has varying scattering properties along at least one dimension of the diffuser.

7. The lamp of claim 1, wherein said light source is a solid state light source.

8. The lamp of claim 1, further comprising a wavelength conversion element arranged in the light path between said light source and diffuser.

9. The lamp of claim 8, wherein said conversion element comprises a transparent phosphor carrier.

10. The lamp of claim 8, wherein said wavelength conversion element comprises a phosphor carrier having a transparent, thermally conductive material.

11. The lamp of claim 1, wherein said diffuser comprises a diffuser dome.

12. The lamp of claim 1, wherein said diffuser comprises a substantially rotationally symmetric diffuser dome.

13. The lamp of claim 1, wherein said diffuser comprises a substantially linear diffuser dome.

14. The lamp of claim 1, wherein said diffuser comprises a squat-shaped diffuser dome.

15. The lamp of claim 1, wherein said diffuser comprises a diffusing material, wherein said diffuser has one or more areas covered by a greater amount of diffusing material.

16. The lamp of claim 1, further comprising heat dissipation elements to conduct conversion heat away from said wavelength conversion material.

17. The lamp of claim 8, wherein said conversion element is three-dimensional.

18. The lamp of claim 17, wherein said conversion element is substantially rotationally symmetric.

19. The lamp of claim 17, wherein said conversion element is substantially linear diffuser dome.

20. The lamp claim 8, wherein said conversion element is planar.

21. The lamp of claim 1, wherein said light source comprises a plurality of co-planar light emitting diodes (LEDs).

22. The lamp of claim 8, wherein said conversion element and said diffuser are substantially frusto-spherical such that said phosphor carrier and diffuser provide a double-dome structure.

23. The lamp of claim 1, wherein the light emitted from the diffuser has a spatial uniformity that is within 40% of a mean value within a range of viewing angles.

24. The lamp of claim 1, wherein the light emitted from the diffuser has a spatial uniformity that is within 20% of a mean value within a range of viewing angles.

25. The lamp of claim 6, wherein said varying scattering properties comprises varying scattering surface properties, or varying volume of scattering materials.

26. The lamp of claim 6, wherein said varying scattering properties comprises higher diffuser scattering power in the axis said light source emission of higher light intensity, and lower diffuser scattering power in the axis of said light source emission having a lower light intensity.

27. A lamp, comprising:

a light source; and

an optical element at least partially covering said light source so that at least some light from said light source passes through said optical element, said optical element having scattering properties that vary along at least one dimension of the element to modify the emission distribution of the light emitted by said light source.

28. The lamp of claim 27, wherein said optical element modifies angular distribution of light emitted by said light source.

29. The lamp of claim 27, wherein said light source emits light with a substantially non-uniform emission distribution, said optical element modifying said substantially non-uniform distribution to a substantially uniform distribution.

30. The lamp of claim 27, wherein said light source emits a substantially Lambertian emission pattern, said optical element modifying said substantially Lambertian emission pattern to a substantially uniform emission pattern.

31. The lamp of claim 27 wherein said optical element comprises a diffuser having varying scattering properties.

32. The lamp of claim 31, wherein said diffuser has varying scattering properties along one dimension of the diffuser.

33. The lamp of claim 27, wherein said light source is a solid state light source.

34. The lamp of claim 27, further comprising a wavelength conversion element in the light path between said light source and diffuser.

35. The lamp of claim 34, wherein said conversion element comprises a phosphor carrier.

36. The lamp of claim 34, wherein said conversion element is three-dimensional.

37. The lamp claim 34, wherein said conversion element is planar.

38. The lamp of claim 34, wherein said conversion element is substantially rotationally symmetric.

39. The lamp of claim 30, wherein said conversion element is elongated.

40. The lamp of claim 27, wherein said optical element comprises a diffuser.

41. The lamp of claim 40, wherein said diffuser is substantially rotationally symmetric.

42. The lamp of claim 40, wherein said diffuser has an elongated shape.

43. The lamp of claim 40, wherein said diffuser comprises a squat-shaped dome.

44. The lamp of claim 27, wherein the light emitted from the optical element has a spatial uniformity that is within 40% of a mean value within a range of viewing angles.

45. The lamp of claim 27, wherein the light emitted from the optical element has a spatial uniformity that is within 20% of a mean value within a range of viewing angles.

46. The lamp of claim 27, wherein said varying scattering properties comprises higher diffuser scattering power in the axis said light source emission of higher light intensity, and lower diffuser scattering power in the axis of said light source emission having a lower light intensity.

47. A lighting device comprising:

a light source;

a diffuser spaced from and in the light path of the light source; and

a wavelength conversion element disposed between the light source and the diffuser and spaced from the light source and the diffuser, wherein said diffuser is shaped such that there are different distances between said diffuser and said conversion material at different emission angles.

48. The lighting device of claim 47, wherein said light source is a solid state light source.

49. The lighting device of claim 47, wherein said wavelength conversion element comprises a phosphor carrier having a thermally conductive material.

50. The lighting device of claim 47, wherein said diffuser comprises a diffuser dome.

51. The lighting device of claim 47, wherein said diffuser comprises a squat-shaped diffuser dome.

52. The lighting device of claim 47, wherein said diffuser is substantially rotationally symmetric.

53. The lighting device of claim 47, wherein said diffuser has an elongated shape.

54. The lighting device of claim 47, wherein said diffuser comprises a diffusing material, wherein said diffuser incorporates one or more areas varying diffusing properties.

55. The lighting device of claim 47, wherein said diffuser comprises diffusing properties that vary across one or more areas of the diffuser.

56. The lighting device of claim 47, wherein said diffuser disperses light from said light source and/or said wavelength conversion material.

57. The lighting device of claim 47, further comprising heat dissipation elements to conduct conversion heat away from said wavelength conversion element.

58. The lighting device of claim 47, wherein said wavelength conversion element is three-dimensional.

59. The lighting device of claim 47, wherein said wavelength conversion element is planar.

60. The lighting device of claim 47, wherein said conversion element is substantially rotationally symmetric.

61. The lighting device of claim 47, wherein said conversion element is elongated.

62. The lighting device of claim 47, wherein said light source comprises a plurality of co-planar light emitting diodes (LEDs).

63. The lighting device of claim 47, wherein said light source comprises a plurality of non-co-planar light emitting diodes (LEDs).

64. The lighting device of claim 47, wherein said wavelength conversion material is substantially frusto-spherical.

65. The lighting device of claim 47, wherein said diffuser is substantially frusto-spherical.

66. The lighting device of claim 47, wherein said wavelength conversion element and said diffuser are substantially frusto-spherical such that said wavelength conversion material phosphor and diffuser provide a double-dome structure.

67. The lighting device of claim 47, wherein said wavelength conversion element and said diffuser are substantially frusto-spherical such that said wavelength conversion material and diffuser comprise a double-rotationally symmetric structure.

68. The lighting device of claim 47, wherein said wavelength conversion element and said diffuser are elongated with said conversion element and diffuser comprising a double-linear elongated structure.

69. The lighting device of claim 47, wherein the space between said light source and said wavelength conversion material and the space between said diffuser and said phosphor comprise light mixing chambers.

70. The lighting device of claim 47, wherein said diffuser at least partially conceals the appearance of said wavelength conversion material when said lighting device is not operating.

71. The lighting device of claim 47, wherein said diffuser exhibits a substantially white appearance when said lighting device is not operating.

72. The lighting device of claims 47, providing a steady state lumen output of at least 800 lumens.

73. The lighting device of claim 47, having emission efficiency of greater than 50 lumens per watt.

74. The lighting device of claim 47, wherein said light source comprises 10 or fewer light emitting diodes.

75. The lighting device of claim 47, wherein said light source comprises a light emitting chip area of 10 mm² or less.

76. The lighting device of claim 47, emitting light with a color render index (CRI) greater than 80.

77. The lighting device of claim 47, wherein the light emitted from the diffuser has a spatial uniformity that is within 40% of a mean value within a range of viewing angles.

78. The lighting device of claim 77, wherein said range of viewing angles is 0 to 135°

.

79. The lighting device of claim 47, wherein the light emitted from the diffuser has a spatial uniformity that is within 20% of a mean value within a range of viewing angles.

80. The lighting device of claim 79, wherein said range of viewing angles is 0 to 135°

.

81. The lighting device of claim 47, wherein the light emitted from the diffuser has a color uniformity that is within a standard deviation on a CIE diagram within a range of viewing angles.

82. The lighting device of claim 81, wherein the standard deviation is a 4-step MacAdams ellipse.

83. The lighting device of claim 81, wherein said range of viewing angles is 0 to 135°

.

84. A lighting device comprising:

a light source;

a diffuser spaced from the light source, said diffuser having areas with different diffusing characteristics; and

a wavelength conversion element disposed between the light source and the diffuser and spaced from the light source and the diffuser.

85. The light emitting device of claim 84, wherein said different diffusing characteristics are provided by areas having differing amounts of diffusing material.

86. The light emitting device of claim 84, wherein said different diffusing characteristics comprise are having differing amounts of diffusing characteristics.

87. The light emitting device of claim 84, wherein said diffuser has a band of material with a differing amount of diffusing material.

88. The light emitting device of claim 87, wherein said band of material can be at an angle within the range 45 to 105 degrees relative to the axis of the diffuser.

89. The light emitting diode of claim 84, wherein said diffuser has a differing amount of diffusing material at a viewing angle 0 and 45 degrees viewing angle.

90. The light emitting device of claim 84, wherein said diffuser is shaped such that there are different distances between said diffuser and said conversion element at different emission angles.

91. The lighting device of claim 84, wherein said diffuser comprises a diffuser dome.

92. The lighting device of claim 84, wherein said diffuser is elongated.

93. The lighting device of claim 85, wherein said diffuser is rotationally symmetric.

94. The lighting device of claim 84, wherein said diffuser comprises a squat-shaped diffuser dome.

95. The lighting device of claim 84, wherein the conversion and/or scattering properties of said conversion element vary across its surface.

96. A lamp, comprising:

a solid state light source emitting in an emission pattern; and

a diffuser arranged to alter said light source emission pattern so that said lamp emits a emission pattern having greater uniformity than said light source emission pattern, said diffuser having a width greater than its height.

97. A lamp, comprising:

a solid state light source emitting in an emission pattern; and

a diffuser arranged to alter said light source emission pattern so that said lamp emits a emission pattern having greater uniformity than said light source emission pattern, said diffuser being shaped with a lateral area having a smaller radius of curvature than a top area.

98. A lighting device comprising:

a solid state light source;

a diffuser spaced from and in the light path of the light source; and

a wavelength conversion element disposed between the light source and the diffuser and spaced from the light source and the diffuser, wherein said conversion element has varying scattering properties and said diffuser has varying scattering propertied, wherein said lamp emits a more uniform pattern than would be emitted by said conversion element or said diffuser diffusing said light source light without the other.