LED lamp incorporating remote phosphor with heat dissipation features

• US 9,500,325 B2
• Filed: 02/16/2011
• Issued: 11/22/2016
• 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: Tong, Tao, Letoquin, Ronan, Keller, Bernd, Tarsa, Eric
• Primary Examiner(s): CARTER, WILLIAM JOSEPH
• Application Number:
  US13/029,025
• Publication Number:
  US 20110215701A1
• Time in Patent Office: 2,106 Days
• Field of Search: 362/293, 362/294
• US Class Current: 1/1
• 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 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 29/502 characterised by the adaptation for cooling of specific components
• CPC Class Codes: F21V 29/506 of globes, bowls or cover glasses
• CPC Class Codes: F21V 29/75 with fins or blades having different shapes, thicknesses or spacing
• CPC Class Codes: F21V 29/76 with essentially identical parallel planar fins or blades, e.g. with comb-like cross-section
• CPC Class Codes: F21V 29/767 the planes containing the fins or blades having directions perpendicular to the light emitting axis
• CPC Class Codes: F21V 29/85 characterised by the material liquid coolants F21V29/56
• CPC Class Codes: F21V 9/30 Elements containing photoluminescent material distinct from or spaced from the light source shades F21V1/17; globes, bowls or cover glasses F21V3/08, F21V3/12; refractors F21V5/10; reflectors F21V7/26, F21V7/30; elements with provision for controlling the spectral properties or intensity F21V9/40
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• 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 2924/00014 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 33/644 in intimate contact or integrated with parts of the device other than the semiconductor body

Abstract

An LED lamp or bulb is disclosed that comprises a light source, a heat sink structure and a remote planar phosphor carrier having at least one conversion material. The phosphor carrier can be remote to the light sources and mounted to the heat sink so that heat from the phosphor carrier spreads into the heat sink. The phosphor carrier can comprise a thermally conductive transparent material and a phosphor layer, with an LED based light source mounted to the heat sink such that light from the light source passes through the phosphor carrier. At least some of the LED light is converted by the phosphor carrier, with some lamp embodiments emitting a white light combination of LED and phosphor light. The phosphor arranged according to the present invention can operate at lower temperature to thereby operate at greater phosphor conversion efficiency and with reduced heat related damage to the phosphor.

Claims

1. A lamp, comprising:

a light source;

a planar phosphor carrier remote to said light source and comprising a thermally conductive material at least partially transparent to light from said light source, and a conversion material that absorbs light from said light source and emits different wavelengths of light; and

a heat sink structure which forms walls of an optical cavity and comprising fins which extend from said walls of said optical cavity in a direction parallel to said planar phosphor carrier, said phosphor carrier thermally coupled to said heat sink structure, said light source mounted within said optical cavity;

wherein said phosphor carrier comprises a carrier layer and a phosphor layer, said carrier layer comprising a first surface adjacent said phosphor layer and a second surface opposite said phosphor layer;

wherein a portion of said first surface is uncovered by said phosphor layer, said uncovered portion of said first surface contacting said heat sink such that said first surface of said carrier layer and said phosphor layer are adjacent to said heat sink and said second surface of said carrier layer is opposite said heat sink.

2. The lamp of claim 1, wherein said phosphor carrier comprises scattering particles.

3. The lamp of claim 1, wherein said phosphor carrier comprises a separate layer containing scattering particles.

4. The lamp of claim 1, wherein said phosphor carrier comprises a surface that is roughened.

5. The lamp of claim 1, wherein heat from said phosphor carrier conducts into said heat sink structure through said thermal coupling.

6. The lamp of claim 1, wherein said light source comprises an LED based light source.

7. The lamp of claim 1, wherein said light source comprises a blue emitting LED and said phosphor carrier comprises a phosphor that absorbs blue light and re-emits a different wavelength of light, said lamp emitting a perceived white light combination of blue LED light and conversion material light.

8. The lamp of claim 1, said phosphor carrier mounted over an opening in said optical cavity, with light from said light source passing through said phosphor carrier.

9. The lamp of claim 8, wherein said optical cavity comprises reflective surfaces.

10. A light emitting diode (LED) based lamp, comprising:

an LED light source;

a planar phosphor remote to said light source such that light emitted from said light source passes through said phosphor and is converted by said phosphor;

a heat sink which forms the walls of an optical cavity, said light source mounted within said cavity;

wherein said planar phosphor comprises a phosphor carrier and said phosphor carrier comprises a phosphor layer and a carrier layer and, said carrier layer comprising a first surface adjacent said phosphor layer and a second surface opposite said phosphor layer, wherein a portion of said first surface is uncovered by said phosphor layer; and

a thermally conductive path to conduct phosphor conversion heat away from said planar phosphor and to dissipate said heat, wherein a portion of said first surface is uncovered by said phosphor layer, said uncovered portion of said first surface contacting said thermally conductive path, wherein said first surface of said carrier layer and said phosphor layer are adjacent to said thermally conductive path and said second surface of said carrier layer is opposite said thermally conductive path.

11. The lamp of claim 10, said thermally conductive path at least partially comprising said heat sink.

12. The lamp of claim 10, wherein said phosphor carrier comprises a thermally conductive transparent material.

13. The lamp of claim 10, further comprising scattering particles.

14. The lamp of claim 10, wherein said light source comprises a blue emitting LED and said phosphor layer absorbs blue light and re-emits a different wavelength of light, said lamp emitting a perceived white light combination of blue LED light and phosphor light.

15. The lamp of claim 10, said planar phosphor over an opening in said cavity, with light from said light source passing through said planar phosphor.

16. The lamp of claim 15, wherein said optical cavity comprises reflective surfaces.

17. A lamp, comprising:

a heat sink structure comprising fins, said heat sink structure forming an optical cavity;

a light emitting diode (LED) based light source in said cavity;

a conversion material comprising a planar phosphor layer and a carrier layer, said carrier layer comprising a first surface adjacent to said phosphor layer and a second surface opposite said phosphor layer, said conversion material remote to said light source and which absorbs light from said light source and re-emits light in different wavelengths, such that said fins extend from said optical cavity in a direction parallel to said planar phosphor layer, wherein a portion of said first surface is uncovered by said phosphor layer, said uncovered portion of said first surface contacting said heat sink such that said first surface of said carrier layer and said phosphor layer is adjacent to said heat sink and said second surface of said carrier layer is opposite said heat sink; and

a first thermally conductive path to conduct conversion generated heat away from said conversion material to said heat sink;

wherein said planar phosphor layer is between said light source and said carrier layer.

18. The lamp of claim 17, said conversion material on an optical cavity opening, with light from said light source passing through said conversion material.

19. The lamp of claim 18, further comprising a platform within said optical cavity, said light source mounted on said cavity with heat dissipating from said light source through said platform.

20. The lamp of claim 18, wherein said optical cavity comprises reflective surfaces.

21. The lamp of claim 17, wherein heat from said first light source is conducted away from said light source through a second thermally conductive path.

22. The lamp of claim 21, wherein said first and second thermally conductive paths are coupled.

23. The lamp of claim 21, wherein said first and second thermally conductive paths are de-coupled.