Gas cooled LED lamp
In one embodiment, a lamp comprises an optically transmissive enclosure. An LED array is disposed in the optically transmissive enclosure operable to emit light when energized through an electrical connection. A gas is contained in the enclosure to provide thermal coupling to the LED array. The gas may include oxygen.
1. A lamp comprising:
an optically transmissive enclosure connected to a base to define an interior space;
an LED array disposed in the optically transmissive enclosure operable to emit light when energized through an electrical connection;
a gas contained in the enclosure to provide thermal coupling to the LED array; and
a heat sink structure thermally coupled to the LED array for transmitting heat from the LED array to the enclosure primarily through the gas, wherein the heat sink structure is positioned entirely inside of the enclosure and is spaced from the base such that the heat sink structure is supported in the interior space at a distance from the enclosure of less than 8 mm.
2. The lamp of claim 1 where the LED array is disposed at one end of an LED assembly and the heat sink structure extends at least substantially to one side of the LED array.
3. The lamp of claim 1 wherein the heat sink structure comprises fins.
4. The lamp of claim 2 wherein the LED array is disposed toward a top of the LED assembly and the heat sink structure extends toward a bottom of the LED assembly.
5. The lamp of claim 1 wherein the LED array is disposed on an LED assembly and the LED assembly is supported on a glass stem where the heat sink structure at least partially surrounds the glass stem.
6. The lamp of claim 1 wherein the LED array is positioned such that it is disposed substantially in the center of the enclosure and the heat sink structure is offset to one side of the enclosure.
7. The lamp of claim 1 wherein the heat sink structure contacts the enclosure.
8. The lamp of claim 1 wherein the gas comprises helium.
9. The lamp of claim 1 wherein the gas comprises hydrogen.
10. A lamp comprising:
an optically transmissive enclosure;
an LED array disposed in the optically transmissive enclosure to be operable to emit light when energized through an electrical connection;
a gas contained in the enclosure to provide thermal coupling to the LED array; and
a heat sink structure thermally coupled to the LED array for transmitting heat from the LED array to the gas, where the heat sink structure comprises an outside surface that supports the LED array and faces the enclosure and an inside surface that faces away from the enclosure where the inside surface and the outside surface are surrounded by the gas.
11. A lamp comprising:
an optically transmissive enclosure;
an LED array disposed in the optically transmissive enclosure to be operable to emit light when energized through an electrical connection, the LED array being thermally coupled to the enclosure; and
an electrically insulating base comprising an upper part that is connected to the enclosure and a separate lower part that is a separate component from the upper part and that is joined to the upper part and an electrical connector connected to the lower part that forms part of the electrical connection to the LED assembly.
12. The lamp of claim 11 wherein the electrical connector comprises an Edison screw.
13. The lamp of claim 11 wherein the base has a relatively narrow proximal end that is secured to the enclosure where a diameter of the base gradually increases from the proximal end to a point along the base.
14. The lamp of claim 13 wherein a portion of the base with a larger diameter defines an internal space for receiving a power supply.
15. The lamp of claim 11 wherein the base has a relatively narrow proximal end that is secured to the enclosure where a diameter of the base gradually increases from the proximal end to a point along the base and the diameter of the base gradually narrows from the point to the electrical connector.
16. The lamp of claim 11 wherein an external surface of the base is formed by a smooth curved shape.
17. The lamp of claim 16 wherein the external surface of the base transitions from a relatively smaller concave portion to a relatively larger convex portion from the proximal end to the electrical connector.
18. The lamp of claim 1 wherein the heat sink structure is spaced from the enclosure.
19. A lamp comprising: an optically transmissive sealed enclosure; an LED array disposed in the optically transmissive enclosure operable to emit light when energized through an electrical connection, the LED array forming part of an LED assembly comprising a light transmissive submount; a gas contained in the enclosure to provide thermal coupling to the LED array where the gas comprises oxygen, the gas surrounding the LED array such that heat is transmitted from the LED assembly primarily through the gas, and a gas movement device.
20. The lamp of claim 19 where the oxygen is provided in the enclosure in an amount that is sufficient to prevent degradation of the LED array.
21. The lamp of claim 19 where the gas comprises less than approximately 40% by volume of oxygen.
22. The lamp of claim 21 where the gas comprises a second thermally conductive gas.
23. The lamp of claim 22 where the second thermally conductive gas has a higher thermal conductivity than oxygen.
24. The lamp of claim 22 where the second thermally conductive gas comprises helium, the helium comprising at least 40% by volume of the gas.
25. The lamp of claim 19 where the gas has a thermal conductivity of about at least 87.5 mW/m-K.
26. The lamp of claim 19 where the lamp emits light equivalent to a 60 watt equivalent bulb and the gas comprises approximately 100% by volume of oxygen.
27. The lamp of claim 19 wherein the gas movement device comprises at least one of an electric fan, a rotary fan, a piezoelectric fan, corona or ion wind generator, and diaphragm pump.
28. The lamp of claim 19 where the lamp emits light equivalent to a 40 watt equivalent bulb and the gas comprises approximately 1-5% by volume of oxygen.
29. The lamp of claim 19 where the gas comprises at least approximately 4% by volume of oxygen.
30. The lamp of claim 19 where the gas comprises less than approximately 50% by volume of oxygen.
31. The lamp of claim 19 where the gas comprises less than approximately 5% by volume of oxygen.
32. The lamp of claim 19 where the gas comprises approximately 40-60% by volume of oxygen.
33. The lamp of claim 19 wherein the LED assembly is supported on a glass stem where the glass stem is fused to the enclosure.
34. The lamp of claim 19 wherein the LED assembly is supported on a glass stem where the glass stem is fused to the enclosure and wherein the electrical connection comprises a thermally resistive electrical path configured to prevent overtemperature of the LED array during fusing of the glass stem to the enclosure.