Method of making optical light engines with elevated LEDs and resulting product

• US 7,633,093 B2
• Filed: 01/31/2006
• Issued: 12/15/2009
• Est. Priority Date: 05/05/2003
• Status: Active Grant

• Current Assignee: Lighting Science Group Corporation (Pegasus Capital Advisors, L.P.)
• Original Assignee: Lighting Science Group Corporation (Pegasus Capital Advisors, L.P.)
• Inventors: Blonder, Greg, Harrah, Shane
• Primary Examiner(s): Fahmy, Wael
• Assistant Examiner(s): ARMAND, MARC ANTHONY
• Application Number:
  US11/343,986
• Publication Number:
  US 20060186423A1
• Time in Patent Office: 1,414 Days
• Field of Search: 257/13, 257 79-103, 257/918, 257/E51.018, 257/E51.022, 257/E33.001, 257/E33.007, 257/E25.032
• US Class Current: 257/81
• 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 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 2924/01087 Francium [Fr]
• 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 33/54 having a particular shape
• 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
• CPC Class Codes: H05K 1/0204 using means for thermal conduction connection in the thickness direction of the substrate H05K1/0207 takes precedence
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: Y10S 257/918 : Light emitting regenerative switching device, e.g. light emitting scr arrays, circuitry

Abstract

An optical light engine is fabricated by providing a thermally conductive base having one or more mounting pedestals for elevating one or more LED die above the base'"'"'s surface. The LED die are mounted on the pedestals, electrically connected, and a mold having a molding surface for molding a dome centered around the LED die is disposed on the base over the pedestal-mounted LED die. The encapsulating material is then injected through an input port disposed in the base to mold the dome around the LED die. The encapsulant material is cured and the mold is removed. In an advantageous embodiment, the light engine comprises a ceramic-coated metal base made by the low temperature co-fired ceramic-on-metal process (LTCC-M).

Claims

1. An optical light engine comprising:

a base including an input port and an output port, each of the input port and the output port extending from one side of the base to the other side of the base;

a pedestal disposed and adapted to support one or more LED die above a surface of the base;

one or more LED die mounted on the pedestal; and

a dome disposed over one or more of the LED die, the dome comprising a solid form of material having a first integrally formed post disposed substantially within the input port from the one side of the base to the other side, and a second integrally formed post disposed substantially within the output port from the one side of the base to the other side, wherein the solid form of material is in intimate contact with the one or more LED die, the input port and the output port, and wherein the solid form of material is an injection molding material.

2. The optical light engine of claim 1, wherein each of the dome is approximately centered about the pedestal.

3. The optical light engine of claim 1, wherein the base includes one or more layers of ceramic coating having a surface cavity formed therein.

4. The optical light engine of claim 1, wherein the dome is hemispheric.

5. The optical light engine of claim 1, wherein the molding material comprises silicone.

6. The optical light engine of claim 1, wherein the molding material comprises epoxy.

7. The optical light engine of claim 1, wherein the pedestal comprises a thermally conductive material.

8. The optical light engine of claim 1, wherein the base comprises a thermally conductive material.

9. The optical light engine of claim 1, wherein the pedestal comprises a heat sink underlying the base.

10. The optical light engine of claim 9, wherein the base comprises a printed wiring board including an aperture disposed and adapted to allow the pedestal to project therethrough.

11. The optical light engine of claim 1, wherein the pedestal is plated with a reflective material.

12. The optical light engine of claim 1, wherein the base comprises a printed wiring board including an aperture and the pedestal is retained in such aperture so as to be fastened within the base.

13. The optical light engine of claim 1, wherein the pedestal includes a surface cavity wherein the one or more LED die are attached.

14. The optical light engine of claim 1, wherein at least a portion of the output port is substantially parallel to the base.

15. The optical light engine of claim 14, wherein the output port comprises a closed end thereby forming a reservoir for the excess molding material.

16. The optical light engine of claim 1, wherein the pedestal is disposed on top of the base and the one or more LED die is disposed on top of the pedestal.

17. The optical light engine of claim 1, wherein each of the input port and the output port extend completely through the base from one side of the base to the other side of the base creating respective through-holes in the base.

18. The optical light engine of claim 3, wherein the pedestal is mounted within the surface cavity.

19. The optical light engine of claim 3, wherein the pedestal extends above a surface of the base at least as high as a top surface of the one or more ceramic layers.

20. The optical light engine of claim 3, wherein the one or more ceramic layers include metallization and each of the one or more LED die is electrically connected by wire bonding to the metallization.

21. The optical light engine of claim 4, wherein the LED die is mounted on the pedestal at an elevation at an approximate center of the hemispheric dome.

22. The optical light engine of claim 9, wherein the printed wiring board comprises a FR4 material.

23. The optical light engine of claim 12, wherein the printed wiring board comprises a FR4 material.

24. The optical light engine of claim 12, wherein the pedestal comprises a Cu/Mo/Cu alloy.

25. An optical light engine array comprising:

a common base including one or more input ports and one or more output ports, each of the one or more input ports and the one or more output ports extending from one side of the common base to the other side of the common base creating respective through-holes in the common base;

at least one pedestal supported by the common base;

an LED die mounted on each of the at least one pedestal such that each respective LED die is positioned above an upper surface of the common base; and

a dome disposed over each respective one of the at least one pedestal, each respective dome comprising a solid form of material having a first integrally formed post disposed substantially within at least one of the input ports from the one side of the base to the other side, and a second integrally formed post disposed substantially within at least one of the output ports from the one side of the base to the other side, wherein the solid form of material is in intimate contact with the respective LED die, the respective input port, and the respective output port, and wherein the solid form of material is an injection molding material;

wherein each respective LED die is elevated by the pedestal to an approximate center of the dome.

26. An optical light engine comprising:

a base including an input port and an output port, each of the input port and the output port extending from one side of the base to the other side of the base;

a pedestal supported by the base;

an LED die mounted on the pedestal; and

a dome disposed over one or more of the LED die, the dome comprising a solid form of material having a first integrally formed post disposed substantially within the input port, and a second integrally formed post disposed substantially within the output port, wherein the solid form of material is in intimate contact with the one or more LED die, the input port and the output port, and wherein the solid form of material is an injection molding material;

wherein the LED die is mounted on the pedestal at an elevation such that the LED die is elevated to approximately the center of the dome.