Solid state lighting units and methods of forming solid state lighting units

• US 7,959,325 B2
• Filed: 11/17/2006
• Issued: 06/14/2011
• Est. Priority Date: 11/18/2005
• Status: Active Grant

• Current Assignee: IDEAL Industries Lighting, LLC (Ideal Industries Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Sims, Paul E., You, Chenhua, Roberts, John K.
• Primary Examiner(s): Alavi; Ali
• Application Number:
  US11/601,500
• Publication Number:
  US 20070115671A1
• Time in Patent Office: 1,670 Days
• Field of Search: 362/249.02, 362/249.06, 362/240, 362/367, 362/245, 362/246
• US Class Current: 362/249.02
• 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: 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: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133613 characterized by the sequence of light sources
• CPC Class Codes: G09F 9/35 being liquid crystals G09F9/302 takes precedence; liquid crystal materials C09K19/00; liquid crystal panels comprising a number of electrodes in a single cell per se G02F1/13
• CPC Class Codes: H01L 2224/45014 Ribbon connectors, e.g. rectangular cross-section
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 2224/85205 Ultrasonic bonding
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2924/206 Length ranges
• CPC Class Codes: H05B 45/00 Circuit arrangements for operating light-emitting diodes [LED]
• CPC Class Codes: H05B 45/40 Details of LED load circuits
• CPC Class Codes: H05K 1/142 Arrangements of planar printed circuit boards in the same plane, e.g. auxiliary printed circuit insert mounted in a main printed circuit
• CPC Class Codes: H05K 1/181 associated with surface mounted components
• CPC Class Codes: H05K 3/0058 Laminating printed circuit boards onto other substrates, e.g. metallic substrates H05K1/0281 takes precedence
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A solid state lighting unit includes a plurality of solid state lighting tiles including a planar surface and a plurality of solid state light sources on the planar surface. The lighting unit includes a plurality of bar support members. Respective ones of the bar support members include at least two of the plurality of tiles affixed thereon to form respective bar assemblies, and respective ones of the solid state light sources on the solid state lighting tiles of a bar assembly are electrically connected in series so as to be simultaneously energized upon application of a voltage thereto. Methods of forming a solid state lighting unit are also disclosed.

Claims

1. A solid state lighting unit, comprising:

a plurality of solid state lighting tiles, each of the solid state lighting tiles comprising a planar surface and a plurality of solid state light sources on the planar surface; and

a plurality of bar support members, wherein respective ones of the bar support members include at least two of the plurality of tiles affixed thereon to form respective bar assemblies;

wherein respective ones of the solid state light sources on the solid state lighting tiles of a bar assembly are electrically connected in series so as to be simultaneously energized upon application of a voltage thereto.

2. The solid state lighting unit of claim 1, further comprising:

a panel support member, wherein the plurality of bar assemblies are affixed to the panel support member on a side of the bar support members of the bar assemblies opposite the solid state lighting tiles.

3. The solid state lighting unit of claim 2, wherein the panel support member comprises a cover bottom affixed to the plurality of bar assemblies opposite the plurality of solid state lighting tiles.

4. The solid state lighting unit of claim 3, further comprising a thermal spreader on the cover bottom.

5. The solid state lighting unit of claim 4, wherein the thermal spreader comprises a sheet of thermally conductive material having an area and configured to conduct heat generated by the solid state lighting devices to the cover bottom and to reduce thermal nonuniformities in the solid state lighting unit by spreading the conducted heat over the area of the thermal spreader.

6. The solid state lighting unit of claim 4, wherein the thermal spreader is between the cover bottom and the plurality of bar assemblies.

7. The solid state lighting unit of claim 4, wherein the cover bottom is between the thermal spreader and the plurality of bar assemblies.

8. The solid state lighting unit of claim 4, wherein the thermal spreader comprises a first thermal spreader between the cover bottom and the plurality of bar assemblies, the solid state lighting unit further comprising a second thermal spreader, wherein the cover bottom is between the first thermal spreader and the second thermal spreader.

9. The solid state lighting unit of claim 1, wherein each of the plurality of bar assemblies comprises a thermally conductive elongate member, and wherein the plurality of bar assemblies are arranged side by side in the solid state lighting unit.

10. The solid state lighting unit of claim 1, wherein each of the plurality of bar assemblies further comprises a loopback connector at an end of the bar assembly.

11. The solid state lighting unit of claim 1, further comprising a plurality of spacers between adjacent ones of the solid state lighting tiles on a respective bar assembly.

12. The solid state lighting unit of claim 11, wherein each of the plurality of spacers comprises a nonconductive elastomeric material.

13. The solid state lighting unit of claim 12, wherein each of the plurality of spacers comprises a protrusion configured to mate with a corresponding recess in at least one of the adjacent solid state lighting tiles.

14. The solid state lighting unit of claim 11, wherein respective ones of the tiles comprise electrical pads on the planar surface thereof, the solid state lighting unit further comprising:

a wire loop extending between electrical pads on adjacent tiles to electrically interconnect the electrical pads of adjacent tiles across a spacer between the tiles.

15. The solid state lighting unit of claim 14, wherein the height of the wire loop from the planar surface is between about 0.02 and about 0.12 inches.

16. The solid state lighting unit of claim 11, further comprising an insulating material on the wire loop.

17. The solid state lighting unit of claim 11, wherein the electrical pads are in electrical communication with one or more of LED chips through circuit traces on the tile such that when sufficient voltage is applied across the electrical pads, current flows through the light sources and the light sources emit useful light.

18. The solid state lighting unit of claim 1, further comprising a reflector panel on the plurality of lighting tiles.

19. The solid state lighting unit of claim 18, wherein the reflector panel comprises a diffuse light reflector.

20. The solid state lighting unit of claim 18, wherein the reflector panel comprises a plurality of circular apertures therein that are aligned with respective ones of the plurality of solid state lighting elements, and wherein the solid state lighting elements are at least partially disposed within the respective apertures.

21. The solid state lighting unit of claim 20, wherein the apertures circular apertures having sidewalls that form an angle with the planar surface of the tiles.

22. The solid state lighting unit of claim 18, further comprising a plurality of pins comprising a body and a head, wherein reflector panel is attached to the tiles using the pins, wherein the pins extend through a hole in the reflector panel and into a corresponding hole in a tile.

23. The solid state lighting unit of claim 22, wherein the pins comprise a diffuse light reflective material.

24. The solid state lighting unit of claim 22, wherein the pins extend into the tiles but not into the bar support members.

25. The solid state lighting unit of claim 2, further comprising a fastener extending between at least one of the bar support members and the panel support member, wherein the fastener has a head on a side of the bar support member opposite the panel support member, and wherein the head is at least partially disposed within an aperture in a tile and has a height less than a height of the tile.

26. The solid state lighting unit of claim 25, wherein the head is spaced apart from the tile such that it is not in contact with the tile.

27. The solid state lighting unit of claim 25, further comprising a reflector panel on the plurality of lighting tiles.

28. The solid state lighting unit of claim 27, further comprising a plurality of pins comprising a body and a head, wherein reflector panel is attached to the tiles using the pins, wherein the pins extend through a hole in the reflector panel and into a corresponding hole in a tile.

29. The solid state lighting unit of claim 28, wherein the pins extend into the tiles but not into the bar support members.

30. A solid state lighting unit, comprising:

a panel support member;

a plurality of solid state lighting tiles, each of the solid state lighting tiles comprising a planar surface and a plurality of solid state light sources on the planar surface; and

a plurality of bar support members, wherein respective ones of the bar support members include at least two of the plurality of tiles affixed thereon to form respective bar assemblies;

wherein the bar assemblies are mounted on the panel support member such that the bar support members are between the panel support member and the tiles.

31. The solid state lighting unit of claim 30, further comprising a thermal spreader between the panel support member and the plurality of bar assemblies, wherein the thermal spreader comprises a sheet of thermally conductive material having an area and configured to conduct heat generated by the solid state lighting devices to the panel support member and to reduce thermal nonuniformities in the solid state lighting unit by spreading the conducted heat over the area of the thermal spreader.

32. The solid state lighting unit of claim 31, further comprising a reflector panel on the plurality of lighting tiles.

33. The solid state lighting unit of claim 32, further comprising a plurality of pins comprising a body and a head, wherein reflector panel is attached to the tiles using the pins, wherein the pins extend through a hole in the reflector panel and into a corresponding hole in a tile.

34. The solid state lighting unit of claim 33, wherein the pins extend into the tiles but not into the bar support members.

35. The solid state lighting unit of claim 32, further comprising a fastener extending between at least one of the bar support members and the panel support member, wherein the fastener has a head on a side of the bar support member opposite the panel support member, and wherein the head is at least partially disposed within an aperture in a tile and has a height less than a height of the tile.

36. The solid state lighting unit of claim 35, wherein the head is spaced apart from the tile such that it is not in contact with the tile.

37. A solid state lighting unit comprising:

at least one bar support member;

first and second solid state lighting tiles on the bar support member;

a nonconductive elastomeric spacer between the first and second solid state lighting tiles.

39. The solid state lighting unit of claim 37, wherein the spacer comprises a protrusion configured to mate with a corresponding recess in at least one of the first or second solid state lighting tiles.

40. The solid state lighting unit of claim 37, further comprising:

electrical pads on surfaces of the first and second tiles opposite the bar support member; and

a wire loop extending between the electrical pads to electrically interconnect the electrical pads across the spacer.

41. The solid state lighting unit of claim 40, wherein the height of the wire loop from the planar surface is between about 0.02 and about 0.12 inches.

42. The solid state lighting unit of claim 40, further comprising:

a plurality of parallel wire loops extending between the electrical pads to provide a redundant electrical interconnection between the electrical pads.

43. The solid state lighting unit of claim 37, further comprising:

first and second adjacent electrical contacts on a surface of the first lighting tile opposite the bar support member;

third and fourth adjacent electrical contacts on a surface of the second lighting tile opposite the bar support member;

a first wire loop extending between the first electrical pad of the first lighting tile and the third electrical pad of the second lighting tile to electrically interconnect the first and third electrical pads across the spacer;

a second wire loop extending between the second electrical pad of the first lighting tile and the fourth electrical pad of the second lighting tile to electrically interconnect the second and fourth electrical pads across the spacer;

wherein the first and second wire loops are spaced apart by a distance d that is at least about equal to a height h of the first and second wire loops from the surfaces of the first and second lighting tiles.

44. The solid state lighting unit of claim 43, wherein the height h of the first and second wire loops is less than about half of the distance d between the first and second wire loops.

38. A solid state lighting tile, comprising:

a substrate having a planar surface, a first end, a second end opposite the first end, and a longitudinal center axis extending between the first end and the second end;

a plurality of first strings of series-connected LEDs on the surface of the substrate, the first strings having respective anode contacts at the first end of the tile and cathode contacts at the second end of the tile; and

a plurality of second strings of series-connected LEDs, the second strings having respective anode contacts at the second end of the tile and cathode contacts at the first end of the tile, wherein;

each of the plurality of first strings and the plurality of second strings includes at least a first color string of LEDs configured to emit light having a first wavelength when energized, and a second color string of LEDs configured to emit light having a second wavelength when energized;

the first plurality of strings and the second plurality of strings run generally parallel to the longitudinal center axis; and

the anode and cathode contacts of the first color string of the first plurality of strings and the anode and cathode contacts of the first color string of the second plurality of strings are disposed nearer to the longitudinal center axis of the tile than the anode and cathode contacts of the second color string of the first plurality of strings and the anode and cathode contacts of second color string of the second plurality of strings.

45. A solid state lighting tile, comprising:

a substrate having a planar surface;

a plurality of first strings of series-connected LEDs on the substrate, the first strings having respective anode contacts at a first end of the tile and cathode contacts at a second end of the tile opposite the first end; and

a plurality of second strings of series-connected LEDs, the second strings having respective anode contacts at the second end of the tile and cathode contacts at the first end of the tile;

wherein each of the plurality of first strings and the plurality of second strings includes at least a first color string of LEDs configured to emit light having a first wavelength when energized and a second color string of LEDs configured to emit light having a second wavelength when energized; and

wherein the cathode contact of the first color string of the first plurality of strings and the anode contact of the first color string of the second plurality of strings are offset in a direction parallel to the longitudinal center axis of the tile from the cathode contact of the second color string of the first plurality of strings and the anode contact of the second color string of the second plurality of strings.

46. The solid state lighting tile of claim 45, wherein the cathode contact of the first color string of the first plurality of strings and the anode contact of the first color string of the second plurality of strings are farther from the second end of the tile than the cathode contact of the second color string of the first plurality of strings and the anode contact of the second color string of the second plurality of strings.

47. A method of forming a solid state lighting bar assembly including a bar support member comprising a plurality of registration holes and a plurality of solid state lighting tiles comprising at least one registration hole each, the method comprising:

placing the bar support member on a jig including at least one alignment pin aligned with one of the registration holes in the bar support member so that the alignment pin extends through the registration hole; and

placing one of the plurality of tiles on the bar support member such that the alignment pin extends through the registration hole in the tile; and

affixing the tile to the bar support member.

48. The method of claim 47, wherein affixing the tile to the bar support member comprises dispensing an adhesive on the bar support member before placing the tile on the bar support member.

49. The method of claim 47, wherein the tile comprises a first tile including a contact pad adjacent an end thereof and wherein the jig includes a second alignment pin, the method further comprising:

placing a second tile including a contact pad adjacent an end thereof on the jig such that the second alignment pin extends through the registration hole in the second tile and such that the end of the second tile is adjacent the end of the first tile; and

electrically connecting the contact pad of the first tile and the contact pad of the second tile.

50. The method of claim 49, wherein electrically connecting the contact pad of the first tile and the contact pad of the second tile comprises forming a loop connection between the contact pad of the first tile and the contact pad of the second tile.

51. The method of claim 50, further comprising:

forming an insulating material on the loop connection.

52. The method of claim 50, wherein the height of the loop connection is between about 0.02 and about 0.12 inches.

53. The method of claim 50, wherein forming a loop connection between the contact pad of the first tile and the contact pad of the second tile comprises forming a plurality of parallel loop connections between the contact pad of the first tile and the contact pad of the second tile.

54. The method of claim 50, wherein the first tile comprises first and second contact pads and wherein the second tile comprises first and second contact pads, the method further comprising:

forming a first loop connection between the first contact pad of the first tile and the first contact pad of the second tile and forming a second loop connection between the second contact pad of the first tile and the second contact pad of the second tile, wherein the first and second loop connections are spaced apart by a distance d that is at least about equal to a height h of the first and second loop connections.

55. The method of claim 54, wherein the height h of the first and second loop connections is less than about half of the distance d between the first and second loop connections.

56. The method of claim 49, wherein electrically connecting the contact pad of the first tile and the contact pad of the second tile comprises providing a wire ribbon connection between the first tile and the second tile.

57. The method of claim 49, further comprising:

providing an insulating spacer between the first tile and the second tile.

58. The method of claim 57, wherein providing an insulating spacer between the first tile and the second tile comprises dispensing a liquid sealant in a seam between the first tile and the second tile and curing the dispensed liquid sealant.

59. The method of claim 57, wherein providing an insulating spacer between the first tile and the second tile comprises pressing a pre-formed insulating member in a seam between the first tile and the second tile.

60. The method of claim 59, wherein the preformed insulating member comprises a protrusion configured to mate with a corresponding recess in an edge of the first or second tile.