Illumination assembly using circuitized strips

• US 20060098438A1
• Filed: 11/05/2004
• Published: 05/11/2006
• Est. Priority Date: 11/05/2004
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Meis, Michael A., Ouderkirk, Andrew J., Epstein, Kenneth A., Schultz, John C., Tran, Hung T., Aeschliman, Denny G.
• Granted Patent: US 7,303,315 B2
• Time in Patent Office: Days
• US Class Current: 362/294
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• 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 2924/01079 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 2924/12041 LED
• CPC Class Codes: H01L 2924/15153 the die mounting substrate comprising a recess for hosting the device
• CPC Class Codes: H01L 2924/1517 Multilayer substrate
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• 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 1/0203 Cooling of mounted components H05K1/0272 takes precedence
• CPC Class Codes: H05K 1/182 associated with components mounted in the printed circuit board, e.g. insert mounted components [IMC]
• CPC Class Codes: H05K 2201/066 Heatsink mounted on the surface of the PCB heatsink inserted in the PCB H05K2201/10416
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H05K 3/0097 Processing two or more printed circuits simultaneously, e.g. made from a common substrate, or temporarily stacked circuit boards H05K3/0052 takes precedence
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

An illumination assembly includes a heat dissipating member having a plurality of circuitized strips disposed thereon a spaced relationship. Each circuitized strip includes an electrically insulative substrate having at least one circuit trace on a first side of the substrate and an electrically and thermally conductive layer on a second side of the substrate, such that the at least one circuit trace is electrically insulated from the second side of the substrate. The circuitized strips have a plurality of vias extending from the first side to the second side of the substrate. A plurality of LEDs are disposed in the plurality of vias, such that each LEDs is disposed on the electrically and thermally conductive layer on the second side of the substrate and electrically connected to the at least one circuit trace on the first side of the substrate.

Claims

1. An illumination assembly, comprising:

a heat dissipating member;

a plurality of circuitized strips disposed on the heat dissipating member in a spaced relationship, each such strip including an electrically insulative substrate having at least one circuit trace on a first side of the substrate and an electrically and thermally conductive layer on a second side of the substrate, the at least one circuit trace being electrically insulated from the second side of the substrate, the circuitized strips also having a plurality of vias extending from the first side to the second side of the substrate; and

a plurality of LEDs disposed in the plurality of vias, each of the LEDs disposed on the electrically and thermally conductive layer on the second side of the substrate and electrically connected to the at least one circuit trace on the first side of the substrate.

2. The assembly of claim 1, wherein the LEDs are electrically connected to the electrically and thermally conductive layer on the second side of the substrate.

3. The assembly of claim 2, wherein the heat dissipating member is electrically conductive, and wherein the electrically and thermally conductive layer on the second side of the substrate is electrically connected to the heat dissipating member.

4. The assembly of claim 1, wherein the plurality of vias of each substrate strip are arranged in a single line.

5. The assembly of claim 1, further comprising an optical film disposed between at least two adjacent circuitized strips.

6. The assembly of claim 1, wherein the circuitized strips are flexible.

7. The assembly of claim 1, wherein the electrically insulative substrate comprises a material selected from the group comprising polyimide, polyester, polyethyleneterephthalate (PET), optically reflective insulative polymers, multilayer optical film (MOF), polycarbonate, polysulfone, FR4 epoxy composite, and combinations thereof.

8. The assembly of claim 7, wherein the electrically insulative substrate consists essentially of multilayer optical film (MOF).

9. The assembly of claim 6, wherein the thermally and electrically conductive layer on the second side of the substrate comprises a material selected from the group comprising copper, nickel, gold, aluminum, tin, lead, and combinations thereof.

10. The assembly of claim 1, wherein a single LED is disposed in each of the plurality of vias.

11. The assembly of claim 1, wherein at least one of the plurality of vias does not have any LED disposed therein.

12. The assembly of claim 1, wherein each LED is electrically coupled to the at least one circuit trace by a wirebond.

13. The assembly of claim 1, wherein each LED is disposed within the respective via in electrical contact with the electrically conductive layer on the second side of the substrate.

14. An illumination assembly, comprising:

a flexible circuit comprising an electrically insulative substrate having at least one circuit trace on a first side thereof, and a plurality of vias extending through the substrate from the first side to a second side of the substrate;

an LED disposed in at least one of the plurality of vias; and

an electrically conductive heat dissipating member disposed proximate the second side of the flexible circuit;

wherein the LED is electrically connected to both the heat dissipating member and the at least one circuit trace.

15. The assembly of claim 14, wherein the LED is one of a plurality of LEDs disposed in the vias, wherein each of the plurality of LEDs is electrically connected to both the heat dissipating member and the at least one circuit trace.

16. The assembly of claim 14, wherein the flexible circuit is one of a plurality of flexible circuits positioned on the heat dissipating member in a spaced relationship, each flexible circuit comprising an electrically insulative substrate having at least one circuit trace on a first side thereof, and a plurality of vias extending through the substrate from the first side to a second side of the substrate, wherein each flexible circuit includes an LED in at least one of the vias, and wherein the LEDs are electrically connected to the heat dissipating member.

17. A method for producing an illumination assembly, comprising:

providing an electrically insulative substrate;

providing a plurality of circuit traces on the electrically insulative substrate;

providing a plurality of rows of vias in the electrically insulative substrate, each row of vias having at least one associated circuit trace;

separating the substrate into a plurality of strips, each strip including one of the plurality of rows of vias and associated circuit trace;

populating at least one via of each strip with an LED, the LED electrically connected to the associated circuit trace; and

disposing at least two of the plurality of strips on a heat sink to form an array of LEDs, wherein the LEDs of each strip are electrically connected to the heat sink.

18. The method of claim 17, wherein the rows of vias are spaced from each other by a first distance prior to separating the substrate into a plurality of strips, and by a second distance after mounting to a printed circuit board.

19. The method of claim 18, wherein the first distance is smaller than the second distance.

20. The method of claim 17, wherein the electrically insulative substrate comprises a material selected from the group comprising polyimide, polyester, polyethyleneterephthalate (PET), optically reflective insulative polymers, multilayer optical film (MOF), polycarbonate, polysulfone, FR4 epoxy composite, and combinations thereof.

21. The method of claim 20, wherein the electrically insulative substrate consists essentially of multilayer optical film (MOF).