Surface mountable light emitting diode assemblies packaged for high temperature operation

• US 7,528,421 B2
• Filed: 07/12/2005
• Issued: 05/05/2009
• Est. Priority Date: 05/05/2003
• Status: Expired due to Term

• Current Assignee: Lighting Science Group Corporation (Pegasus Capital Advisors, L.P.)
• Original Assignee: Lamina Lighting, Inc.
• Inventors: Mazzochette, Joseph
• Primary Examiner(s): Ngo, Ngan
• Assistant Examiner(s): LIU, BENJAMIN T
• Application Number:
  US11/179,863
• Publication Number:
  US 20060006405A1
• Time in Patent Office: 1,393 Days
• Field of Search: 257/81, 257/88, 257/98, 257/99, 257/100, 257/676, 257/707, 257/708, 257/E33.057, 257/E33.058, 257/E33.059, 257/E33.075, 257/82
• US Class Current: 257/99
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 2924/01012 Magnesium [Mg]
• CPC Class Codes: H01L 2924/0102 Calcium [Ca]
• CPC Class Codes: H01L 2924/01025 Manganese [Mn]
• CPC Class Codes: H01L 2924/01046 Palladium [Pd]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/19041 being a capacitor
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/641 characterized by the materials
• CPC Class Codes: H01L 33/642 characterized by the shape
• CPC Class Codes: H01L 33/647 the elements conducting electric current to or from the semiconductor body

Abstract

Light emitting diode (LED) assemblies packaged for high temperature operation and surface mounting. In particular, the LED assemblies according to the present invention are constructed to include a thermally conducting base and an optically efficient cavity that provides protection for the LED assembly and maximizes light extraction. The LED assemblies are particularly adapted for easy and efficient surface mounting or bolt down assembly mounting in high temperature environments.

Claims

1. A LED assembly adapted for surface mounting and high temperature operation, the LED assembly comprising:

a thermally conducting base, wherein at least a portion of the thermally conducting base is substantially planar;

one or more electrically insulating layers overlying at least a portion of the planar portion of the thermally conducting base and defining a surface cavity, wherein the electrically insulating layers include one or more terminals;

one or more LED die disposed at least partially within the surface cavity, wherein the one or more LED die are in thermal contact with the planar portion of the thermally conducting base, and electrically connected to the one or more terminals of the one or more insulating layers,

wherein a bottom surface of the LED assembly includes a thermally conductive region in solderable thermal contact with the thermally conducting base, for spreading heat transmitted to the base from the one or more LED die; and

further comprising an LED assembly mount selected from the group consisting of an electrically insulated fastener and a solderable bonding pad.

2. The LED assembly of claim 1, wherein the thermally conductive region is an integral part of the thermally conducting base.

3. The LED assembly of claim 1, wherein the bottom surface of the LED assembly further comprises one or more electrically conductive regions adapted for electrical connection with the one or more terminals, and adapted for electrical insulation from the thermally conductive region.

4. The LED assembly of claim 1 further comprising one or more metal leads extending beyond a periphery of the LED assembly for providing an electrical path to the one or more LED die.

5. The LED assembly of claim 4, wherein the one or more metal leads are vertically sandwiched between a pair of insulating layers overlying the thermally conducting base, the leads overhanging the edge of the LED assembly.

6. The LED assembly of claim 1, wherein the thermally conducting base includes a metal base.

7. The LED assembly of claim 6, wherein the metal base includes one or more holes.

8. The LED assembly of claim 1, wherein the one or more electrically insulating layers include one or more layers of ceramic.

9. The LED assembly of claim 1, wherein the thermally conducting base and the one or more electrically insulating layers comprise a ceramic-coated metal structure made according to a LTCC-M fabrication process.

10. The LED assembly of claim 1, wherein the one or more LED die are at least partially encapsulated within the cavity.

11. A device comprising:

a heat sink;

an apertured board overlying the heat sink;

one or more LED assemblies mounted on the apertured board and thermally coupled to the heat sink by a heat spreader, wherein each of the one or more LED assemblies includes;

a thermally conducting base, wherein at least a portion of the thermally conducting base is substantially planar,

one or more electrically insulating layers overlying at least a portion of the planar portion of the thermally conducting base and defining a surface cavity, wherein the electrically insulating layers include one or more terminals, and

one or more LED die disposed at least partially within the surface cavity, wherein the one or more LED die are in thermal contact with the planar portion of the thermally conducting base and electrically connected to the one or more terminals of the one or more insulating layers,

wherein a bottom surface of the LED assembly includes a thermally conductive region in thermal contact with the thermally conducting base, for spreading heat transmitted to the base from the one or more LED die; and

further comprising an LED assembly mount selected from the group consisting of an electrically insulated fastener and a solderable bonding pad.

12. The device according to claim 11, wherein the heat spreader extends through the apertured board from the bottom of the LED assembly to the heat sink.

13. The device according to claim 11, wherein the one or more LED assemblies each include one or more metal leads extending beyond a periphery of the LED assembly for providing an electrical path to the one or more LED die.

14. The device according to claim 13, wherein the one or more metal leads are attached to the apertured board.

15. The device of claim 11, wherein the one or more LED die are at least partially encapsulated within the cavity.

16. The device according to claim 11, wherein the thermally conducting base and the one or more electrically insulating layers comprise a ceramic-coated metal structure made according to a LTCC-M fabrication process.

17. A device comprising:

an apertured board;

one or more LED assemblies mounted underlying the apertured board, wherein each of the one or more LED assemblies includes;

a thermally conducting base, wherein at least a portion of the thermally conducting base is substantially planar,

one or more electrically insulating layers overlying at least a portion of the planar portion of the thermally conducting base and defining a surface cavity, wherein the electrically insulating layers include one or more terminals, and

one or more LED die disposed at least partially within the surface cavity, wherein the one or more LED die are in thermal contact with the planar portion of the thermally conducting base and electrically connected to the one or more terminals of the one or more insulating layers,

wherein a bottom surface of the LED assembly includes a thermally conductive region in thermal contact with the thermally conducting base, for spreading heat transmitted to the base from the one or more LED die;

a heat sink thermally coupled to the bottom surface of each of the one or more LED assemblies; and

further comprising an LED assembly mount selected from the group consisting of an electrically insulated fastener and a solderable bonding pad.

18. The device of claim 17, wherein each of the one or more LED die are aligned with an aperture in the apertured board.

19. The device of claim 17, wherein the one or more LED die are at least partially encapsulated within the cavity.

20. The device according to claim 17, wherein the thermally conducting base and the one or more electrically insulating layers comprise a ceramic-coated metal structure made according to a LTCC-M fabrication process.

21. A device comprising:

an apertured board;

a heat sink;

one or more LED assemblies mounted between the apertured board and the heat sink, wherein each of the one or more LED assemblies includes;

a metal base including one or more holes, wherein at least a portion of the metal base is substantially planar,

one or more ceramic layers overlying at least a portion of the planar portion of the metal base and defining a surface cavity, wherein the ceramic layers include one or more terminals, and

one or more LED die disposed at least partially within the surface cavity, wherein the one or more LED die are in thermal contact with the planar portion of the metal base and electrically connected to the one or more terminals of the one or more ceramic layers,

wherein a bottom surface of the LED assembly includes a thermally conductive region in thermal contact with the metal base, for spreading heat transmitted to the base from the one or more LED die; and

further comprising an LED assembly mount selected from the group consisting of an electrically insulated fastener and a solderable bonding pad.

22. The device of claim 21, wherein the one or more LED assemblies are mounted between the apertured board and the heat sink by fasteners extending through the holes in the metal base, such that the one or more LED die are aligned with respective apertures in the apertured board.

23. The device of claim 21, wherein the one or more LED die are at least partially encapsulated within the cavity.

24. The device according to claim 21, wherein the thermally conducting base and the one or more electrically insulating layers comprise a ceramic-coated metal structure made according to a LTCC-M fabrication process.