Light emitting diodes packaged for high temperature operation
View Patent ↗In accordance with the invention, an LED packaged for high temperature operation comprises a metal base including an underlying thermal connection pad and a pair of electrical connection pads, an overlying ceramic layer, and a LED die mounted overlying the metal base. The LED is thermally coupled through the metal base to the thermal connection pad, and the electrodes are electrically connected to the underlying electrical connection pads. A low thermal resistance insulating layer can electrically insulate other areas of die from the base while permitting heat passage. Heat flow can be enhanced by thermal vias to the thermal connector pad. Ceramic layers formed overlying the base can add circuitry and assist in distributing emitted light. The novel package can operate at temperatures as high as 250° C.
1. A packaged LED for high temperature operation comprising:
a metal base, the metal base including an underlying thermal connection pad and a pair of underlying electrical connection pads;
a layer of ceramic overlying the metal base; and
an LED mounted on the ceramic layer, wherein the LED includes a pair of electrodes electrically connected to respective underlying electrical connection pads, and wherein the LED is thermally coupled to the metal base by one or more thermal vias, and thermally coupled through the metal base to the thermal connection pad.
2. The packaged LED of claim wherein the underlying electrical connection pads and the underlying thermal connection pad are coplanar to permit surface mounting on corresponding pads of a PC board.
3. The packaged LED of claim 1 wherein at least one electrode of the LED is connected to one of the underlying electrical connection pads by an electrical path including a bonding wire from the electrode to a bonding pad on the ceramic layer.
4. The packaged LED of claim 1 wherein at least one electrode of the LED is connected to one of the underlying electrical connection pads by an electrical path including an insulated conducting via through the metal base.
5. The packaged LED of claim 1 wherein at least one electrode of the LED is connected to one of the underlying electrical connection pads by an electrical path including the metal base.
6. An array of LEDs comprising a plurality of LEDs according to claim 1 overlying a common metal base.
7. A packaged LED for high temperature operation comprising:
a metal base, the metal base including an underlying thermal connection pad and a pair of underlying electrical connection pads;
a layer of ceramic overlying the metal base; and
an LED having a pair of electrodes overlying the metal base, wherein the LED is thermally coupled through the metal base to the thermal connection pad and at least one electrode is electrically connected to at least one of the underlying electrical connection pads by an electrical path including an insulated conducting via through the metal base.
8. The packaged LED of claim 7 , wherein the layer of ceramic includes a cavity and the LED is mounted in the cavity.
9. The packaged LED of claim 8 , wherein the cavity has tapered sides to reflect light from the LED.
10. The packaged LED of claim 7 , wherein the metal base includes a concave region to reflect light and the LED is mounted overlying the concave region.
11. The packaged LED of claim 7 , wherein the underlying electrical connection pads and the underlying thermal connection pad are coplanar to permit surface mounting on corresponding pads of a PC board.
12. The packaged LED of claim 7 , wherein the LED is mounted on the ceramic layer overlying the thermal connection pad and the LED is thermally coupled by one or more thermal vias to the metal base overlying the thermal connection pad.
13. The packaged LED of claim 7 , wherein at least one electrode of the LED is connected to one of the underlying electrical connection pads by an electrical path including a bonding wire from the electrode to a bonding pad on the ceramic layer.
14. The packaged LED of claim 7 , wherein at least one electrode of the LED is connected to one of the underlying electrical connection pads by an electrical path including the metal base.
15. An array of LEDs comprising a plurality of LEDs according to claim 7 overlying a common metal base.
16. A packaged LED for high temperature operation comprising:
a metal base, the metal base including an underlying thermal connection pad and a pair of underlying electrical connection pads;
a layer of electrically insulating material overlying the metal base; and
an LED mounted on the layer of electrically insulating material, wherein the LED includes a pair of electrodes electrically connected to respective underlying electrical connection pads, and wherein the LED is thermally coupled to the metal base by one or more thermal vias, and thermally coupled through the metal base to the thermal connection pad.
17. The packaged LED of claim 16 , wherein the underlying electrical connection pads and the underlying thermal connection pad are coplanar to permit surface mounting on corresponding pads of a PC board.
18. The packaged LED of claim 16 , wherein at least one electrode of the LED is connected to one of the underlying electrical connection pads by an electrical path including a bonding wire from the electrode to a banding pad on the layer of electrically insulating material.
19. The packaged LED of claim 16 , wherein at least one electrode of the LED is connected to one of the underlying electrical connection pads by an electrical path including an insulated conducting via through the metal base.
20. The packaged LED of claim 16 , wherein at least one electrode of the LED is connected to one of the underlying electrical connection pads by an electrical path including the metal base.
21. An array of LEDs comprising a plurality of LEDs according to claim 16 overlying a common metal base.
22. A packaged LED for high temperature operation comprising:
a metal base, the metal base including an underlying thermal connection pad and a pair of underlying electrical connection pads;
a layer of electrically insulating material overlying the metal base; and
an LED having a pair of electrodes overlying the metal base, wherein the LED is thermally coupled through the metal base to the thermal connection pad and at least one electrode is electrically connected to at least one of the underlying electrical connection pads by an electrical path including an insulated conducting via through the metal base.
23. The packaged LED of claim 22 , wherein the layer of electrically insulating material includes a cavity and the LED is mounted in the cavity.
24. The packaged LED of claim 23 , wherein the cavity has tapered sides to reflect light from the LED.
25. The packaged LED of claim 22 , wherein the metal base includes a concave region to reflect light and the LED is mounted overlying the concave region.
26. The packaged LED of claim 22 , wherein the underlying electrical connection pads and the underlying thermal connection pad are coplanar to permit surface mounting on corresponding pads of a PC board.
27. The packaged LED of claim 22 , wherein the LED is mounted on the layer of electrically insulating material overlying the thermal connection pad and the LED is thermally coupled by one or more thermal vias to the metal base overlying the thermal connection pad.
28. The packaged LBD of claim 22 , wherein at least one electrode of the LED is connected to one of the underlying electrical connection pads by an electrical path including a bonding wire from the electrode to a bonding pad on the layer of electrically insulating material.
29. The packaged LED of claim 22 , wherein at least one electrode of the LED is connected to one of the underlying electrical connection pads by an electrical path including the metal base.
30. An may of LEDs comprising a plurality of LEDs according to claim 22 overlying a common metal base.