LED device for wide beam generation

• US 7,674,018 B2
• Filed: 02/26/2007
• Issued: 03/09/2010
• Est. Priority Date: 02/27/2006
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Illumination Management Solutions Incorporated (Eaton Corporation PLC.)
• Inventors: Holder, Ronald G., Rhoads, Greg
• Primary Examiner(s): Lee; Jong-Suk (James)
• Assistant Examiner(s): Crowe; David R
• Application Number:
  US11/711,218
• Publication Number:
  US 20070201225A1
• Time in Patent Office: 1,107 Days
• Field of Search: 362/800, 362/326, 362/335, 362/336, 362/337, 362/338, 362/339, 362/340, 362/235, 362/236, 362/237, 362/240, 362/244, 362/246, 362/249, 362/311, 362/612, 362/227, 362/317, 362/97.3, 257/98, 257/100, 359/718, 359/720, 359/741, 313/500, 313/512, 313/110, 313/112
• US Class Current: 362/311.06
• 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: F21K 9/69 Details of refractors forming part of the light source
• CPC Class Codes: F21S 8/085 of high-built type, e.g. street light
• CPC Class Codes: F21S 8/086 with lighting device attached sideways of the standard, e.g. for roads and highways
• CPC Class Codes: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: F21V 19/02 with provision for adjustment, e.g. for focusing
• CPC Class Codes: F21V 23/005 the substrate is supporting also the light source
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 31/005 Sealing arrangements therefor
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21W 2131/103 of streets or roads
• CPC Class Codes: F21Y 2105/16 square or rectangular, e.g. for light panels
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: G02B 19/0071 adapted to illuminate a complete hemisphere or a plane extending 360 degrees around the source
• CPC Class Codes: G02B 27/0012 Optical design, e.g. procedures, algorithms, optimisation routines
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

An apparatus and method is characterized by providing an optical transfer function between a predetermined illuminated surface pattern, such as a street light pattern, and a predetermined energy distribution pattern of a light source, such as that from an LED. A lens is formed having a shape defined by the optical transfer function. The optical transfer function is derived by generating an energy distribution pattern using the predetermined energy distribution pattern of the light source. Then the projection of the energy distribution pattern onto the illuminated surface is generated. The projection is then compared to the predetermined illuminated surface pattern to determine if it acceptably matches. The process continues reiteratively until an acceptable match is achieved. Alternatively, the lens shape is numerically or analytically determined by a functional relationship between the shape and the predetermined illuminated surface pattern and predetermined energy distribution pattern of a light source as inputs.

Claims

1. An apparatus for illuminating a selected surface with an illumination pattern comprising:

a light source with a radiation pattern having a centerline; and

lens means optically coupled to the light source for primarily refracting light into an azimuthally asymmetric beam having more than one director of principal candela of the illumination pattern off the centerline to produce an azimuthally asymmetric illumination pattern on the selected surface so that the maximum candela is off the centerline and so that substantially all of the light from the light source is collected and substantially all of the collected light is primarily refracted into the beam.

2. The apparatus of claim 1 where the lens means comprises directors of the principal candela of light emitted from the light source which is directed off the centerline by 15°

or more.

3. The apparatus of claim 1 where the lens means directs light onto the illumined surface to provide a 50 percent of maximum foot-candle measurement at an angle greater than 15 degrees from the centerline of the illumination pattern.

4. The apparatus of claim 1 where the lens means comprises a lens base, the surface shape of the lens means proximate to the lens base and between the lens base and the refracting lobe being at least partially undercut.

5. The apparatus of claim 1 where the light source comprises an LED and where the lens means provides the predetermined illuminated surface pattern from a predetermined energy distribution pattern of the LED, the lens means having an undercut surface for generating a portion of the predetermined illumination surface pattern using a corresponding portion of the predetermined energy distribution pattern of the LED so that substantially all of the light from the LED is directed into the predetermined illumination surface pattern.

6. The apparatus of claim 1 where the light source has a near field and where the lens means has a lobed surface which comprises a first surface portion for collecting the light rays directly emitted by the light source and incident on the first surface portion to direct the light rays along a predetermined azimuthal direction and where a second surface portion of the lens means collects light from the light source in the near field of the light source to direct the light toward the predetermined azimuthal direction.

7. The apparatus of claim 1 where the light source has a near field;

and where the lens means is positioned in and utilizes a surface portion of the lens means in the near field of the light source to direct light into an asymmetric spread beam incident on the selected surface.

8. The apparatus of claim 1 where the light source has a near field and where the lens means has a centerline plane and directs light from the light source into the beam across the centerline plane by a surface portion of the lens means located in the near field of the light source.

9. The apparatus of claim 1 where the light source has a centerline plane and a near field;

and where the lens means directs light from the light source into a first portion of the beam across the centerline plane of the light source to shift light from one side of the light source to an opposing side of the light source, and directs light from the near field of the light source into a second portion of the beam directed into a direction different from the first portion of the beam.

10. The apparatus of claim 1 where the light source has a centerline plane and a near field;

and where the lens means includes a first surface portion which directs light from the light source into the azimuthally asymmetric spread beam, a second surface portion of the lens means which directs light from the light source into a portion of the azimuthally asymmetric spread beam across the centerline plane of the light source to shift light from one side of the light source to an opposing side of the light source, a third portion of the lens means being located in the near field of the light source, which third surface portion is effective to direct light from the light source into the azimuthally asymmetric spread beam.

11. The apparatus of claim 1 further comprising a luminaire for providing a selected illuminated pattern on a traveled surface where the light source includes a near field and where the lens means has a surface shape for transforming the radiation pattern of the light source to produce a full-cutoff beam in compliance with IES standards.

12. The apparatus of claim 1 further comprising a carrier in or on which the lens means is disposed, where the lens means is provided with an indexing flange and where the lens means is azimuthally oriented with respect to the carrier by the indexing flange.

13. The apparatus of claim 1 where the light source comprises an LED.

14. The apparatus of claim 1 further comprising an index matching material disposed between the light source and the lens means.

15. The apparatus of claim 1 where the light source comprises an LED and where the lens means comprises an LED package providing both protective passivation for the LED and optical processing of light from the LED.

16. The apparatus of claim 15 further comprising a plurality of LED packages combined into or onto a light bar.

17. The apparatus of claim 16 further comprising a plurality of light bars combined into or onto an array of light bars.

18. The apparatus of claim 17 further comprising a plurality of arrays combined with a fixture as a luminaire.

19. The apparatus of claim 1 further comprising a plurality of light sources and corresponding plurality of lens means combined into at least one array for providing the predetermined illumination pattern on the surface, each light source and lens means having a substantially identical energy distribution pattern which produces the predetermined illuminated surface pattern with the predetermined beam spread to collectively produce a linearly additive illumination pattern with the predetermined beam spread matching the beam spread of the predetermined illuminated surface pattern of each lens means and light source combination.

20. The apparatus of claim 1 further comprising a plurality of light sources and corresponding plurality of lens means combined into at least one array for providing the predetermined illumination pattern on the surface, each light source and lens means having one of a plurality of unique energy distribution patterns which collectively produce the predetermined beam spread.

21. The apparatus of claim 1 further comprising a plurality of light sources and corresponding plurality of lens means combined into at least one array for providing the predetermined illumination pattern on the surface, each light source and lens means having a substantially identical energy distribution pattern which is oriented in a selected one of a plurality of orientations in the array to collectively produce the illumination pattern with the predetermined beam spread.

22. The apparatus of claim 1 further comprising a plurality of light sources and lens means combined into or onto a light bar.

23. The apparatus of claim 22 further comprising a plurality of light bars as modular units positioned in a common plane and angularly oriented in parallel to each other for scaling the intensity of the illumination pattern on the target surface without substantial modification of the illumination pattern by modular scaling of the light bars into a larger or smaller collection.

24. The apparatus of claim 22 where the light bar comprises a planar carrier.

25. The apparatus of claim 1 further comprising a plurality of light sources and corresponding plurality of lens means combined into or onto a light bar for providing the predetermined illumination pattern on the surface, where the light bar comprises a carrier and where each lens means has an indexing flange mountable onto the carrier in a selected one of a plurality of orientations.

26. The apparatus of claim 1 further comprising a plurality of light sources and corresponding plurality of lens means combined into or onto a light bar for providing the predetermined illumination pattern on the surface, where the light bar comprises a carrier, and further comprising a plurality of circuit drivers disposed on or into the carrier corresponding to the plurality of light sources.

27. The apparatus of claim 26 where the plurality of circuit drivers are electrically integrated into or onto the carrier for coupling with the plurality of light sources without the use of a separate printed circuit board.

28. The apparatus of claim 26 further comprising discrete wiring and where the plurality of circuit drivers are directly electrically coupled to the light sources by the discrete wiring.

29. The apparatus of claim 24 where the plurality of light sources and lens means are weather sealed to the carrier by a potting compound, a cover plate, a molded component, a co-molded cover, means for providing a seal or combination thereof.

30. The apparatus of claim 24 where the carrier comprises a heat sink for the plurality of light sources.

31. The apparatus of claim 24 further comprising a heat sink for the plurality of light sources and where the carrier is thermally coupled to the heat sink.

32. The apparatus of claim 26 further comprising a discrete power cable electrically coupled to the plurality of circuit drivers.

33. The apparatus of claim 26 further comprising a power connector coupled to the carrier and electrically coupled to the plurality of circuit drivers.

34. The apparatus of claim 24 further comprising a hold down fitting coupled to the carrier for coupling the light bar into or onto a fixture.

35. The apparatus of claim 24 further comprising an alignment fitting coupled to the carrier for aligning the light bar to a fixture.

36. The apparatus of claim 22 where the plurality of light sources and lens means combined into or onto the light bar are disposed into or onto a carrier and where each lens means has a flange for weather sealing the corresponding light sources into or onto the carrier.

37. The apparatus of claim 1 further comprising a light fixture and where the light source and the lens means are combined with the light fixture.

38. The apparatus of claim 37 further comprising a plurality of light sources and lens means combined into or onto a light bar in the fixture.

39. The apparatus of claim 37 further comprising a plurality of light sources and lens means combined into or onto a plurality of light bars in the fixture.

40. The apparatus of claim 37 employed in a light fixture used for street lighting, roadway lighting, parking lot lighting, pathway lighting, architectural lighting or parking structure lighting where each of the lens means has a surface shape for transforming the radiation pattern of the light source to produce a full-cutoff beam in compliance with IES or other applicable standards.

41. The apparatus of claim 37 where each of the lens means has a surface shape arranged and configured to reduce or totally eliminate light in angular directions toward the horizon or above.

42. The apparatus of claim 37 where each of the lens means is an integral LED package lens.

43. The apparatus of claim 1 wherein the azimuthally asymmetric beam is bisymmetric across a plane including the centerline.

44. The apparatus of claim 1 wherein the lens means has a free form shape to allow designer freedom to shape the beam with any degree of azimuthal asymmetry.

45. The apparatus of claim 1 wherein the centerline is the optical axis of the light source.

46. The apparatus of claim 1 wherein the more than one director of principal candela of the illumination pattern off the centerline includes a maximum director of principal candela.

47. The apparatus of claim 1 wherein the more than one director of principal candela of the illumination pattern off the centerline include directors of principal candela associated with multiple lobes of the illumination pattern.

48. The apparatus of claim 1 wherein the lens means being optically coupled to the light source so that substantially all of the light from the light source is collected and substantially all of the collected light is primarily refracted into the beam comprises a coupling between the lens means and the light source where almost all the energy of the light source is directed into the beam without losses much in excess of those incurred by the light source without the lens deployed.

49. The apparatus of claim 1 wherein the centerline lies in a centerline plane, and wherein the lens means further comprises a complex prism for directing light across the centerline plane of the lens means.

50. An apparatus for illuminating a selected surface with an illumination pattern comprising:

a light source with a radiation pattern having a centerline; and

a lens optically coupled to the light source, wherein the lens primarily refracts light into an azimuthally asymmetric beam having more than one director of principal candela of the illumination pattern off the centerline to produce an azimuthally asymmetric illumination pattern on the selected surface so that the maximum candela is off the centerline and so that substantially all of the light from the light source is collected and substantially all of the collected light is primarily refracted into the beam.

51. An apparatus for illuminating a selected surface with a predetermined illumination pattern on the selected surface comprising:

a light source with a radiation pattern having a centerline; and

an azimuthally asymmetric lens optically coupled to the light source;

having a smooth outer surface with more than one azimuthally asymmetric refracting lobe extending from the outer surface of the lens; and

having a concave outer surface shape on the centerline.

52. The apparatus of claim 51 where the more than one azimuthally asymmetric lobe are each oriented 15°

or more off the centerline.

53. The apparatus of claim 51 where the lens is shaped to direct light onto the illumined surface to provide a 50 percent of maximum foot-candle measurement at an angle greater than 15 degrees from the centerline of the illumination pattern.

54. The apparatus of claim 51 where the lens comprises a lens base, the surface shape of the lens proximate to the lens base and between the lens base and the refracting lobe being at least partially undercut.

55. The apparatus of claim 51 where the source comprises an LED and where the lens provides the predetermined illuminated surface pattern from a predetermined energy distribution pattern of the LED, the lens having an undercut surface for generating a portion of the predetermined illumination surface pattern using a corresponding portion of the predetermined energy distribution pattern of the LED so that substantially all of the light from the LED is directed into the predetermined illumination surface pattern.

56. The apparatus of claim 51 where the light source has a near field and where the lobe of the lens comprises a first surface portion for collecting the light rays directly emitted by the light source and incident on the first surface portion to direct the light rays along a predetermined azimuthal direction and where a second surface portion of the lens collects light from the light source in the near field of the light source to direct the light toward the predetermined azimuthal direction.

57. The apparatus of claim 51 where the light source has a near field;

and where the lens is positioned in and utilizes a surface portion of the lens in the near field of the light source to direct light into an asymmetric spread beam incident on the selected surface.

58. The apparatus .of claim 51 where the light source has a near field and where the lens has a centerline plane and has a surface shaped to direct light from the light source into the beam across the centerline plane by a surface portion of the lens located in the near field of the light source.

59. The apparatus of claim 51 where the light source has a centerline plane and a near field;

and where the lens has a shape to direct light from the light source into a first portion of the beam across the centerline plane of the light source to shift light from one side of the light source to an opposing side of the light source, and directs light from the near field of the light source into a second portion of the beam directed into a direction different from the first portion of the beam.

60. The apparatus of claim 51 where the light source has a centerline plane and a near field;

and where the lens includes a first surface portion which directs light from the light source into the azimuthally asymmetric spread beam, a second surface portion of the lens which directs light from the light source into a portion of the azimuthally asymmetric spread beam across the centerline plane of the light source to shift light from one side of the light source to an opposing side of the light source, a third portion of the lens being located in the near field of the light source, which third surface portion is effective to direct light from the light source into the azimuthally asymmetric spread beam.

61. The apparatus of claim 51 further comprising a luminaire for providing a selected illuminated pattern on a traveled surface where the light source includes a near field and where the lens has a surface shape for transforming the radiation pattern of the light source to produce a full-cutoff beam in compliance with IES standards.

62. The apparatus of claim 51 further comprising a carrier in or on which the lens is disposed, where the lens is provided with an indexing flange and where the lens is azimuthally oriented with respect to the carrier by the indexing flange.

63. The apparatus of claim 51 where the light source comprises an LED.

64. The apparatus of claim 51 further comprising an index matching material disposed between the light source and the lens.

65. The apparatus of claim 51 where the light source is an LED and where the lens comprises an LED package providing both protective passivation for the LED and optical processing of light from the LED.

66. The apparatus of claim 65 further comprising a light bar and a plurality of LED packages combined into or onto the light bar.

67. The apparatus of claim 66 further comprising a plurality of light bars combined into an array of light bars.

68. The apparatus of claim 67 further comprising a plurality of arrays combined with a fixture as a luminaire.

69. The apparatus of claim 51 further comprising a plurality of light sources and corresponding plurality of lens combined into at least one array for providing the predetermined illumination pattern on the surface, each light source and lens combined to produce a substantially identical energy distribution pattern from which the predetermined illuminated surface pattern with the predetermined beam spread is produced to collectively provide a linearly additive illumination pattern with the predetermined beam spread matching the beam spread of the predetermined illuminated surface pattern of each tens and light source combination.

70. The apparatus of claim 51 further comprising a plurality of light sources and corresponding plurality of lenses combined into at least one array for providing the predetermined illumination pattern on the surface, each light source and lens producing in combination one of a plurality of unique energy distribution patterns which collectively produce the predetermined beam spread.

71. The apparatus of claim 51 further comprising a plurality of light sources and corresponding plurality of lenses combined into at least one array for providing the predetermined illumination pattern on the surface, each light source and lens producing in combination a substantially identical energy distribution pattern which is oriented in a selected one of a plurality of orientations in the array to collectively provide the illumination pattern with the predetermined beam spread.

72. The apparatus of claim 51 further comprising a plurality of light sources and lenses combined into or onto a light bar.

73. The apparatus of claim 72 further comprising a plurality of light bars as modular units positioned in a common plane and angularly oriented in parallel to each other for scaling the intensity of the illumination pattern on the target surface without substantial modification of the illumination pattern by modular scaling of the light bars into a larger or smaller collection.

74. The apparatus of claim 72 where the light bar comprises a planar carrier.

75. The apparatus of claim 72 where the plurality of light sources and lenses combined into or onto the light bar are disposed into or onto a carrier and where each lens has an indexing flange mountable onto the carrier in a selected one of a plurality of orientations.

76. The apparatus of claim 72 where the plurality of light sources and lenses combined into or onto the light bar are disposed into or onto a carrier and further comprising a plurality of circuit drivers disposed into or onto the carrier corresponding to the plurality of light sources.

77. The apparatus of claim 76 where the plurality of circuit drivers are electrically integrated into or onto the carrier for coupling with the plurality of light sources without the use of a separate printed circuit board.

78. The apparatus of claim 76 further comprising discrete wiring and where the plurality of circuit drivers are directly electrically coupled to the light sources by the discrete wiring.

79. The apparatus of claim 74 where the plurality of light sources and lenses are weather sealed to the carrier by a potting compound, a cover plate, a molded component, a co-molded cover, means for providing a seal or combination thereof.

80. The apparatus of claim 74 where the carrier comprises a heat sink for the plurality of light sources.

81. The apparatus of claim 74 further comprising a heat sink for the plurality of light sources and where the carrier is thermally coupled to the heat sink.

82. The apparatus of claim 76 further comprising a discrete power cable electrically coupled to the plurality of circuit drivers.

83. The apparatus of claim 76 further comprising a power connector coupled to the carrier and electrically coupled to the plurality of circuit drivers.

84. The apparatus of claim 74 further comprising a hold down fitting coupled to the carrier for coupling the light bar into or onto a fixture.

85. The apparatus of claim 74 further comprising an alignment fitting coupled to the carrier for aligning the light bar to a fixture.

86. The apparatus of claim 72 where the plurality of light sources and lenses combined into or onto the light bar are disposed into or onto a carrier and where each lens has a flange for weather sealing the corresponding light sources into or onto the carrier.

87. The apparatus of claim 51 further comprising a light fixture and where the light source and the lens are combined with the light fixture.

88. The apparatus of claim 87 further comprising a plurality of light sources and lenses combined into or onto a light bar in the fixture.

89. The apparatus of claim 72 further comprising a plurality of light sources and lenses combined into or onto a plurality of light bars in the fixture.

90. The apparatus of claim 89 employed in a light fixture used for street lighting, roadway lighting, parking lot lighting, pathway lighting, architectural lighting or parking structure lighting where each of the lens has a surface shape for transforming the radiation pattern of the light source to produce a full-cutoff beam in compliance with IES or other applicable standards.

91. The apparatus of claim 89 where each of the lens has a surface shape shaped to reduce or totally eliminate of light in angular directions toward the horizon or above.

92. The apparatus of claim 89 where each of the lens is an integral LED package lens.

93. The apparatus of claim 51 wherein the more than one azimuthal asymmetric refracting lobes are different in shape from each other.

94. The apparatus of claim 51 wherein the more than one azimuthal asymmetric refracting lobes are substantially similar in shape to each other.

95. The apparatus of claim 51 wherein the centerline is the optical axis of the light source.

96. The apparatus of claim 51 wherein the more than one azimuthal asymmetric refracting lobes produce a beam that is bisymmetric across a plane including the centerline.

97. The apparatus of claim 51 wherein the more than one azimuthal asymmetric refracting lobes have free form shapes to allow designer freedom to shape the beam with any degree of azimuthal asymmetry.

98. The apparatus of claim 51 wherein the asymmetric refracting lobe extending from the outer surface of the lens is contiguous with the outer surface of the lens.