Mounting arrangement for light emitting diodes

• US 6,712,486 B1
• Filed: 10/19/2000
• Issued: 03/30/2004
• Est. Priority Date: 10/19/1999
• Status: Expired due to Term

• Current Assignee: Permlight Products Inc
• Original Assignee: Permlight Products Inc
• Inventors: Honegger, Gregory W., Popovich, John
• Primary Examiner(s): Tso, Laura K
• Application Number:
  US09/693,548
• Time in Patent Office: 1,258 Days
• Field of Search: 366/800, 366/131, 366/249, 366/252, 366/816, 361/760, 361/719, 361/715, 361/720, 361/721, 257/718, 257/719, 257/726, 257/721
• US Class Current: 362/241
• CPC Class Codes: A47C 7/725 for illumination, e.g. lamps
• 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 9/60 Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
• CPC Class Codes: F21K 9/90 Methods of manufacture
• CPC Class Codes: F21V 19/001 the light sources being semiconductors devices, e.g. LEDs
• CPC Class Codes: F21V 29/507 of means for protecting lighting devices from damage, e.g. housings
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 29/74 with fins or blades
• CPC Class Codes: F21V 29/89 Metals
• CPC Class Codes: F21V 7/0025 Combination of two or more reflectors for a single light source array of reflectors for a cluster of light sources F21V7/0083
• CPC Class Codes: F21V 7/005 with an elongated shape to cooperate with linear light sources
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G09F 13/22 electroluminescent electroluminescent light sources per se H05B33/00
• CPC Class Codes: G09F 9/33 being semiconductor devices, e.g. diodes
• CPC Class Codes: H05K 1/0203 Cooling of mounted components H05K1/0272 takes precedence
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H05K 2201/10446 Mounted on an edge soldering edge mounted components H05K3/3405; edge terminals H05K2201/1034
• CPC Class Codes: H05K 2201/10598 Means for fastening a component, a casing or a heat sink whereby a pressure is exerted on the component towards the PCB
• CPC Class Codes: H05K 3/0061 onto a metallic substrate, e.g. a heat sink heat sinks for electric apparatus H05K7/20
• CPC Class Codes: H05K 3/32 : electrically connecting electric components or wires to printed circuits
• CPC Class Codes: Y10S 362/80 : Light emitting diode
• CPC Class Codes: Y10T 29/49133 : with component orienting
• CPC Class Codes: Y10T 29/49826 : Assembling or joining

Abstract

A modular light emitting diode (LED) mounting configuration is provided including a light source module having a plurality of pre-packaged LEDs arranged in a serial array. The module includes a heat conductive body portion adapted to conduct heat generated by the LEDs to an adjacent heat sink. As a result, the LEDs are able to be operated with a higher current than normally allowed. Thus, brightness and performance of the LEDs is increased without decreasing the life expectancy of the LEDs. The LED modules can be used in a variety of illumination applications employing one or more modules.

Claims

1. A light emitting diode (LED) module for mounting on a heat conducting surface that is substantially larger than the module, the module comprising:

a plurality of LEDs, each LED having at least one lead; and

a circuit board, the circuit board comprising;

a thin dielectric sheet;

a plurality of electrically-conductive contacts on a first side of the dielectric sheet, each of said plurality of contacts being configured to mount a lead of an LED such that said plurality of LEDs is electrically connected; and

a heat conductive body on a second side of said sheet, said body having a first portion in thermal communication with the plurality of contacts through said dielectric sheet, said first portion of said body having a surface area substantially larger than a contact area between the contacts and the dielectric sheet, said body having a second portion adapted to provide thermal contact with the heat conducting surface, the second portion having a surface generally complementary to the heat conducting surface, whereby heat is transferred from the module to the heat conducting surface.

2. The LED module of claim 1, wherein the contacts are substantially flat and coplanar relative to each other.

3. The LED module of claim 2, wherein the plate is substantially flat and parallel to the contacts.

4. The LED module of claim 1, wherein each of the contacts has a portion disposed generally adjacent an edge of the circuit board.

5. The LED module of claim 4, wherein the plurality of LEDs are disposed adjacent one edge of the circuit board.

6. The LED module of claim 5, wherein the LEDs additionally comprise lenses for directing light from the LED in a desired direction, and the LEDs are arranged so that light from the LEDs is directed generally parallel to the circuit board.

7. The LED module of claim 1, wherein the number of contacts is greater than the number of LEDs.

8. The LED module of claim 7, wherein the number of contacts is one greater than the number of LEDs.

9. The LED module of claim 1, wherein the surface area of the first side of the body is greater than a combined surface area of one side of all of the contacts.

10. The LED module of claim 1, wherein each of the contacts has a bonding area wherein at least one of the leads of an associated LED is attached to the contact.

11. The LED module of claim 10, wherein an overall surface of each contact is substantially larger than the bonding area of the contact.

12. The LED module of claim 1, wherein the heat conducting surface behaves as a heat sink.

13. The LED module of claim 1, wherein the dielectric layer comprises an epoxy.

14. The LED module of claim 1, wherein the body is bendable.

15. The LED module of claim 1, wherein the body has a thermal conductivity greater than about 100 W/mK.

16. The LED module of claim 15, wherein the body comprises a metal.

17. The LED module of claim 16, wherein the body comprises aluminum.

18. The LED module of claim 15, wherein the body is electrically non-conductive.

19. The LED module of claim 1, additionally comprising an electrically non-conductive flexible film disposed adjacent the contacts on a side of the contacts opposite the body.

20. The LED module of claim 19, wherein the film comprises reflective film, and the reflective film extends outwardly from the module beyond the LEDs.

21. The LED module of claim 20, wherein the film is attached to the module with at least one rivet.

22. The LED module of claim 20 in combination with a second strip of reflective film that is attached to the heat conducting surface adjacent an edge of the circuit board, and the plurality of LEDs is disposed adjacent the edge of the circuit board so that the LEDs are positioned between the first reflective film and the second reflective film.

23. The LED module of claim 1, wherein the module comprises five pre-packaged, pre-focused LED lamps and six contacts, and the LED lamps are disposed adjacent an edge of the circuit board.

24. The LED module of claim 23, wherein the module is about 0.05 inches thick, 1 inch long, and 0.5 inches wide.

44. The LED module of claim 1, wherein the LEDs are configured to direct light in a direction generally coplanar with the circuit board.

45. The LED module of claim 44, wherein the LEDs are arranged along a side edge of the circuit board.

46. The LED module of claim 45, comprising LED packages that generally abut the side edge of the circuit board.

25. A self-contained illumination apparatus comprising an LED module in combination with a heat conductive base plate having a mount tab, the LED module being mounted onto the mount tab, the module comprising:

a plurality of LEDs, each LED having at least one lead; and

a circuit board, the circuit board comprising;

a thin dielectric sheet;

a plurality of electrically-conductive contacts on a first side of the dielectric sheet, each of said plurality of contacts being configured to mount a lead of an LED such that said plurality of LEDs is electrically connected; and

a heat conductive body on a second side of said sheet, said body having a first portion in thermal communication with the plurality of contacts through said dielectric sheet, said first portion of said body having a surface area substantially larger than a contact area between the contacts and the dielectric sheet, said body having a second portion adapted to provide thermal contact with the heat conducting surface, whereby heat is transferred from the module to the heat conducting surface.

26. The self-contained illumination apparatus of claim 25, wherein the LED module is mounted onto the mount tab with at least one rivet.

27. The self-contained illumination apparatus of claim 25, wherein the base plate behaves as a heat sink.

28. The self-contained illumination apparatus of claim 25 additionally comprising a housing substantially surrounding the LED module, the housing having a cavity, and the LED module positioned to direct light out of the cavity.

29. The self-contained illumination apparatus of claim 25, wherein the apparatus is mounted on a substantially vertical mount surface.

30. The self-contained illumination apparatus of claim 29, wherein the mount surface comprises an end surface of a row of seats.

31. A channel illumination device comprising a plurality of the LED modules in combination with at least one channel defined by a plurality of wall surfaces and a back surface, wherein the LED modules are mounted on at least one of the surfaces of the channel illumination device, and wherein each LED module comprises:

a plurality of LEDs, each LED having at least one lead; and

a circuit board, the circuit board comprising;

a thin dielectric sheet;

a plurality of electrically-conductive contacts on a first side of the dielectric sheet, each of said plurality of contacts being configured to mount a lead of an LED such that said plurality of LEDs is electrically connected; and

a heat conductive body on a second side of said sheet, said body having a first portion in thermal communication with the plurality of contacts through said dielectric sheet, said first portion of said body having a surface area substantially larger than a contact area between the contacts and the dielectric sheet, said body having a second portion adapted to provide thermal contact with the heat conducting surface, whereby heat is transferred from the module to the heat conducting surface.

32. The channel illumination device of claim 31, wherein the plurality of LED modules are electrically connected in parallel relative to each other.

33. The channel illumination device of claim 32, wherein the LED modules are spaced at least about ½

inch from a top surface of the walls.

34. The channel illumination device of claim 32, wherein the wall and back surfaces are coated with a diffusely-reflective coating.

35. The channel illumination device of claim 32, wherein the modules are arranged to direct substantially all of the light emitted by the LEDs toward the wall and back surfaces.

36. The channel illumination device of claim 35, wherein the wall and back surfaces are coated with a diffusely-reflective coating.

37. The channel illumination device of claim 31, wherein the at least one channel surface comprises a heat conducting surface.

38. A low profile modular lighting apparatus for conducting heat away from a light source of the apparatus and to a mounting surface, the apparatus comprising:

a plurality of light emitting diodes (LEDs); and

a circuit board comprising a thermally conductive main body and a plurality of electrically conductive contacts, each of the LEDs electrically communicating with at least one of the contacts in a manner so that the LEDs are configured in a series array;

wherein the plurality of contacts are arranged adjacent a first side of the main body and are in thermal communication with the first side of the main body, the main body electrically insulating the plurality of contacts relative to one another; and

wherein the circuit board is generally planar and a second side of the main body opposite the first side is generally flat to facilitate heat transfer from the main body to the mounting surface and so that the apparatus has a low profile upon the mounting surface.

39. The modular lighting apparatus of claim 38, wherein the main body is electrically nonconductive.

40. The modular lighting apparatus of claim 38, wherein the main body is electrically insulated from the contacts.

41. The modular lighting apparatus of claim 40, wherein the main body is metallic.

42. The modular lighting apparatus of claim 38, wherein the main body has a thermal conductivity greater than about 100 W/mK.

43. The modular lighting apparatus of claim 42, wherein the contacts have a thermal conductivity greater than about 100 W/mK.

47. The apparatus of claim 38, wherein each of the LEDs electrically communicates with corresponding contacts at an attachment area defined on each contact, and an overall surface of the contact is substantially larger than the attachment area.

48. A lighting apparatus, comprising:

a light emitting diode (LED) module mounted on a heat conductive base plate;

the LED module comprising;

a plurality of LED packages, each package comprising an LED and at least one lead; and

a circuit board, comprising a thin dielectric sheet, and a plurality of electrically-conductive contacts on a first side of the dielectric sheet, each of the plurality of contacts being configured to mount a lead of an LED package such that the plurality of LEDs is series connected;

the heat conductive base plate being configured to be mounted on a generally vertical surface and comprising a mount tab;

a housing disposed on the base plate and having a generally downwardly directed opening;

wherein the LED module is attached to the mount tab so that the dielectric sheet is disposed between the mount tab and the plurality of contacts, and the mount tab is in thermal communication with the plurality of contacts through the dielectric sheet, whereby heat is transferred from the LED module to the heat conductive base plate, and the base plate is sized and adapted to behave as a heat sink for the heat transferred thereto from the LED module; and

wherein the LED module is arranged so that the LEDs direct light through the generally downwardly directed opening through the housing.

49. The lighting apparatus of claim 48, wherein the LEDs are arranged to direct light generally in a direction coplanar to the mount tab.

50. The lighting apparatus of claim 49, wherein the LED packages generally abut a side edge of the mount tab.

51. The lighting apparatus of claim 50, wherein the mount tab is angled about 20-45°

relative to a body of the base plate.

52. The lighting apparatus of claim 51, wherein the mount tab is angled about 33°

relative to the body of the base plate.

53. The lighting apparatus of claim 48, wherein the LED module comprises a thermally-conductive base member attached to a second side of the dielectric sheet, and the base member is directly attached to the mount tab.

54. An illuminated signage system, comprising:

at least one channel defined by a plurality of wall surfaces and a back surface;

a translucent material extending over the channel; and

a plurality of light emitting diode (LED) modules disposed within the channel and arranged on at least one of the channel surfaces;

the LED modules being electrically connected to one another in parallel, each of the LED modules comprising;

a plurality of LEDs, each LED having at least one lead; and

a circuit board, comprising a thin dielectric portion, and a plurality of electrically-conductive contacts on a side of the dielectric portion, each of the plurality of contacts being configured to mount a lead of an LED such that the plurality of LEDs are electrically connected;

wherein the LED modules that are attached to the at least one channel surface are mounted so that the dielectric portion is disposed between the channel surface and the plurality of contacts, and the channel surface is in thermal communication with the plurality of contacts through the dielectric portion so that heat is transferred from the LED module to the channel surface.

55. The signage system of claim 54, wherein each of the LED modules additionally comprise a thermally conductive base member connected to a second side of the dielectric portion, the base member comprising a generally flat mounting surface configured to be connected to the channel surface.

56. The signage system of claim 54, wherein each of the plurality of LED modules additionally comprises a reflective layer disposed atop the module so that the module is configured to direct light from the LED in a direction generally coplanar to the contacts.

57. The signage system of claim 56, wherein the LED modules are arranged so that light from the LEDs is directed toward the wall surfaces and bottom surface.

58. The signage system of claim 57, wherein the wall surface and bottom surface are coated with a diffusely-reflective coating.

59. An illuminated signage system, comprising:

at least one channel defined by a plurality of walls, a back surface, and a front, at least a first one of the walls being thermally conductive, the front comprising a translucent material;

at least one lighting module comprising a plurality of light emitting diodes (LEDs) arranged in series on a thermally conductive base;

wherein the at least one module is mounted on the thermally conductive first wall and arranged so that the LEDs do not directly illuminate the translucent front of the channel, and so that heat from the LEDs flows from the module to the thermally conductive first wall.

60. The signage system of claim 59, wherein the at least one module comprises a plurality of LED packages and a circuit board, each package comprising an LED and at least one lead, the circuit board comprising a thin dielectric sheet and a plurality of electrically-conductive contacts disposed on a first side of the dielectric sheet, each of the contacts being configured to mount a lead of an LED package such that the plurality of LEDs is series connected.

61. The signage system of claim 60, wherein the circuit board is generally planar and comprises a generally flat mounting surface so that the module has a low profile when mounted on the first wall.

62. The signage system of claim 60, comprising a plurality of modules arranged along the thermally conductive first wall so that the LEDs do not directly illuminate the translucent front.

63. The signage system of claim 62, wherein the plurality of modules are arranged electrically in parallel relative to one another.