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