Multi-chip light emitting diode modules

• US 8,791,471 B2
• Filed: 11/07/2008
• Issued: 07/29/2014
• Est. Priority Date: 11/07/2008
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Hong Kong Limited (Wolfspeed, Inc.)
• Inventors: Leung, Jacob Chi Wing
• Primary Examiner(s): Tran, Long K
• Assistant Examiner(s): KLEIN, JORDAN M
• Application Number:
  US12/291,293
• Publication Number:
  US 20100117099A1
• Time in Patent Office: 2,090 Days
• Field of Search: 257 88- 93, 257/E33.06, 257/E23.011, 257/E21.023, 257/99
• US Class Current: 257/88
• 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 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• 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 33/483 Containers
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H05K 1/056 the metal substrate being covered by an organic insulating layer
• CPC Class Codes: H05K 2201/0112 Absorbing light, e.g. dielectric layer with carbon filler for laser processing
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]

Abstract

A multi-chip lighting module is disclosed for maximizing luminous flux output and thermal management. In one embodiment, a multi-chip module device comprises a substantially thermally dissipative substrate with a dark insulating layer deposited on a surface of the substrate. A plurality of light emitting devices is also provided. An electrically conductive layer is applied to a surface of the substrate, with the conductive layer comprising a plurality of chip carrier parts each having a surface for carrying at least one of the light emitting devices. Each light emitting device has a first and a second electrical terminal. A reflective layer is also provided that at least partially covers the conductive layer.

Claims

1. A multi-chip module device, comprising:

a substantially thermally dissipative substrate;

a plurality of light emitting devices;

an electrically conductive layer applied to a surface of said substrate, wherein said conductive layer comprises a plurality of chip carrier parts each having a surface for carrying at least one of said light emitting devices;

a reflective coating at least partially between and at least partially surrounding two or more of said light emitting devices and at least partially covering said conductive layer; and

an isolating layer disposed between said reflective coating and said conductive layer, said isolating layer at least partially surrounding two or more of said light emitting devices.

2. The device of claim 1, wherein said substrate comprises a dark insulating layer deposited on a surface of said substrate.

3. The device of claim 2, wherein the substrate further comprises a base layer which comprises Al, and the insulating layer of said substrate is black.

4. The device of claim 2, wherein said substrate further comprises a circuit layer on said substrate, with said circuit layer between said insulating layer and said electrically conductive layer.

5. The device of claim 4, wherein said electrically conductive layer and said circuit layer are in thermal contact to allow for low thermal resistance and heat dissipation.

6. The device of claim 1, wherein said plurality of light emitting devices comprise LEDs.

7. The device of claim 1, wherein each of said light emitting devices is electrically connected to an anode and a cathode.

8. The device of claim 7, wherein said electrically conductive layer further comprises a plurality of connection parts.

9. The device of claim 8, wherein said light emitting devices are electrically and thermally coupled to said chip carrier parts and/or said connection parts via a solder pad or flip-chip mounting.

10. The device of claim 8, wherein said anodes and cathodes are electrically connected to said chip carrier parts and/or said connection parts via wire bonds.

11. The device of claim 7, wherein said anodes are directly electrically and thermally coupled to said chip carrier parts.

12. The device of claim 7, wherein said cathodes are electrically connected to said chip carrier parts via a wire bond.

13. The device of claim 1, wherein said reflective coating covers portions of said electrically conductive layer not occupied by light emitting devices and wire bonds.

14. The device of claim 1, wherein said isolating layer at least partially covers said substrate and said electrically conductive layer, wherein said isolating layer comprises holes to allow for connectivity between said light emitting devices and said electrically conductive layer.

15. The device of claim 1, wherein an electrically insulating and thermally conductive protective layer is at least partially deposited on said electrically conductive layer and said reflective layer, wherein a cavity is formed in said protective layer.

16. The device of claim 1, wherein a lens or collimator is provided above said light emitting devices.

17. The device of claim 1, wherein said light emitting devices emit red, green, blue, white, and/or any combination thereof.

18. The device of claim 1, wherein said electrically conductive layer is made of an electrically conductive metal or metal alloy such as copper, copper alloy, sheet metal, and/or a sheet metal alloy.

19. A single lead frame structure for a multi-chip module, the lead frame comprising:

a plurality of electrically conductive light emitting device chip carrier parts, with each of said carrier parts having a surface carrying at least one light emitting device, each light emitting device having a first electrical terminal and a second electrical terminal, the first terminal of each of said light emitting devices being electrically coupled to said chip carrying surface of said chip carrier part;

a plurality of electrically conductive connection parts separate from said chip carrier parts, each of said connection parts having at least one connection pad;

the second terminal of each of said light emitting devices being electrically coupled to at least one of said connection pads of a corresponding one of said chip carrier parts or one of said connection parts;

a reflective coating at least partially between and at least partially surrounding two or more of said light emitting devices and at least partially covering said carrier parts; and

an isolating layer disposed between said reflective layer and said carrier parts, said isolating layer at least partially between and at least partially surrounding two or more of said light emitting devices.

20. A method for producing a multi-chip lighting module device, said method comprising:

providing a thermally dissipative substrate;

depositing an insulating layer on substantially all of the top surface of said substrate;

applying an electrically conductive layer at least partially covering a surface of said insulating layer, said conductive layer carrying a plurality of light emitting devices;

electrically coupling said light emitting devices with portions of said electrically conductive layer;

depositing an isolating layer at least partially covering said conductive layer, said isolating layer at least partially surrounding two or more of said light emitting devices and

depositing a reflective coating at least partially over said isolating layer, said reflective coating at least partially between and at least partially surrounding two or more of said light emitting devices and at least partially covering said conductive layer.

21. A multi-chip module device, comprising:

a substantially thermally dissipative substrate;

a plurality of light emitting devices;

an electrically conductive layer applied to a surface of said substrate, wherein said conductive layer comprises a plurality of chip carrier parts each having a surface for carrying at least one of said light emitting devices;

a reflective coating at least partially between and at least partially surrounding two or more of said light emitting devices and at least partially covering said conductive layer; and

a protective coating at least partially between and at least partially surrounding two or more of said light emitting devices and at least partially covering said conductive layer.

22. The device of claim 21, wherein said protective coating is also reflective.

23. The device of claim 21, wherein said protective coating is comprised of TiO₂.

24. The device of claim 21, further comprising:

an isolating layer disposed between said reflective coating and said conductive layer, said isolating layer at least partially surrounding two or more of said light emitting devices.