Apparatus for dissipating thermal energy generated by current flow in semiconductor circuits

• US 8,168,990 B2
• Filed: 03/19/2010
• Issued: 05/01/2012
• Est. Priority Date: 03/19/2009
• Status: Expired due to Fees

• Current Assignee: CID Technologies LLC
• Original Assignee: CID Technologies LLC
• Inventors: Christy, Alexander C.
• Primary Examiner(s): Menz, Laura
• Application Number:
  US12/727,990
• Publication Number:
  US 20100237363A1
• Time in Patent Office: 774 Days
• Field of Search: 257/99, 257/88, 257/100
• US Class Current: 257/88
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21V 17/04 the fastening being onto or by the light source
• CPC Class Codes: F21V 29/54 using thermoelectric means, e.g. Peltier elements
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 29/773 the planes containing the fins or blades having the direction of the light emitting axis
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 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

Abstract

A thermal energy dissipating arrangement includes a semiconductor device and a thermally conductive medium. The semiconductor device includes a semiconductor circuit defining a semiconductor junction and encapsulating material in physical contact with and surrounding the semiconductor circuit. The thermally conductive medium defines an opening sized to receive the semiconductor device such that the thermally conductive medium defining the opening is in physical, thermally conductive contact with an exterior surface of the encapsulating material about the semiconductor device with the thermally conductive medium defining the opening intersecting an angle of less than or equal to a predefined angle relative to a plane defined by the semiconductor junction about a periphery of the semiconductor circuit. The thermally conductive medium absorbs thermal energy generated within the semiconductor device as a result of current flow through the semiconductor junction and rejects the absorbed thermal energy to an ambient environment surrounding the thermally conductive medium.

Claims

1. A thermal energy dissipating arrangement, comprising:

a semiconductor device including a semiconductor circuit having a top portion and a bottom portion, the semiconductor circuit defining a semiconductor junction between two dissimilar semiconductor regions, and encapsulating material in physical contact with and completely surrounding the semiconductor circuit, including the top portion and the bottom portion, the semiconductor junction defining a plane, and

a thermally conductive medium defining an opening therethrough sized to receive the semiconductor device such that the thermally conductive medium defining the opening is in physical, thermally conductive contact with an exterior surface of the encapsulating material about the semiconductor device with the thermally conductive medium defining the opening intersecting an angle of less than or equal to a predefined angle relative to the plane defining the semiconductor junction about a periphery of the semiconductor circuit, the thermally conductive medium absorbing thermal energy generated within the semiconductor device as a result of current flow through the semiconductor junction and rejecting the absorbed thermal energy to an ambient environment surrounding the thermally conductive medium.

2. The thermal energy dissipating arrangement of claim 1 wherein the predefined angle is about 60 degrees.

3. The thermal energy dissipating arrangement of claim 1 wherein the predefined angle is about 45 degrees.

4. The thermal energy dissipating arrangement of claim 1 wherein the predefined angle is about 15 degrees.

5. The thermal energy dissipating arrangement of claim 1 wherein the predefined angle is about zero degrees such that the plane defined by the semiconductor junction substantially bisects the thermal energy dissipating medium defining the opening.

6. The thermal energy dissipating arrangement of claim 1 wherein the thermally conductive medium is formed of a material having a thermal conductivity of at least 50 W/mK.

7. The thermal energy dissipating arrangement of claim 1 wherein the thermally conductive medium is formed of a material having a thermal conductivity of at least 200 W/mK.

8. The thermal energy dissipating arrangement of claim 1 wherein the thermally conductive medium defining the opening intersects the plane defining the semiconductor junction about the periphery of the semiconductor circuit.

9. The thermal energy dissipating arrangement of claim 1 wherein the semiconductor circuit is mounted to a mounting surface such that the plane defined by the semiconductor junction is substantially parallel with the mounting surface.

10. The thermal energy dissipating arrangement of claim 9 wherein the thermal energy dissipating medium is separate from, and is not connected to, the mounting surface.

11. The thermal energy dissipating arrangement of claim 1 wherein the thermal energy dissipating medium comprises one or more of copper (Cu), Aluminum (Al), Gold (Au), Silver (Au), Magnesium (Mg), Tin (Sn), Zinc (Zn), Tungsten (W) and Beryllium (Be).

12. The thermal energy dissipating arrangement of claim 1 wherein the thermal energy dissipating medium comprises one of a sheet, strip and ring of thermally conductive material,

and wherein the opening defined through the thermally conductive medium is defined through the one of the sheet, strip and ring of the thermally conductive material.

13. The thermal energy dissipating arrangement of claim 12 wherein the thermally conductive material comprises one or more of copper (Cu), Aluminum (Al), Gold (Au), Silver (Au), Magnesium (Mg), Tin (Sn), Zinc (Zn), Tungsten (W) and Beryllium (Be).

14. The thermal energy dissipating arrangement of claim 13 wherein the one of the sheet, strip and ring of the thermally conductive material defines a plurality of openings therethrough,

and wherein each of the plurality of openings is sized to receive in physical, thermally conductive contact a different one of a corresponding plurality of the semiconductor devices therein.

15. The thermal energy dissipating arrangement of claim 1 wherein the semiconductor device is a light emitting diode (LED),

and wherein the semiconductor circuit is an LED circuit.

16. The thermal energy dissipating arrangement of claim 1 wherein the thermal energy dissipating medium is electrically isolated from the semiconductor circuit.

17. The thermal energy dissipating arrangement of claim 1 further comprising a thermally conductive medium interposed in an interface defined between the thermal energy dissipating medium and the exterior surface of the encapsulating material, the thermally conductive medium facilitating transfer of the thermal energy from the semiconductor device to the thermal energy dissipating medium.

18. The thermal energy dissipating arrangement of claim 17 wherein the thermally conductive medium comprises at least one of a thermally conductive grease and a thermally conductive bonding medium.

19. A thermal energy dissipating arrangement, comprising:

a light emitting diode (LED) including an LED circuit mounted to a mounting surface and defining a semiconductor junction between two dissimilar semiconductor regions, the semiconductor junction defining a plane that is substantially parallel to the mounting surface, and an encapsulating material in physical contact with and surrounding the LED circuit,

a thermal energy dissipating medium having a length and a thickness that is less than the length, the thermal energy dissipating medium defining an opening through the length such that the thickness of the thermal energy dissipating medium defines a wall about a periphery of the opening, the opening sized to receive therethrough the LED such that the wall is in physical, thermally conductive contact with an exterior surface of the encapsulating material about the LED circuit with the wall intersecting an angle of less than or equal to a predefine angle relative to the plane defining the semiconductor junction about a periphery of the LED circuit, the thermally conductive medium absorbing thermal energy generated within the LED as a result of current flow through the semiconductor junction and rejecting the absorbed thermal energy to an ambient environment surrounding the thermally conductive medium, and

a thermally conductive medium interposed in an interface defined between the thermal energy dissipating medium and the exterior surface of the encapsulating material, the thermally conductive medium facilitating transfer of the thermal energy from the LED to the thermal energy dissipating medium.

20. The thermal energy dissipating arrangement of claim 19 wherein the predefined angle is about 60 degrees.

21. The thermal energy dissipating arrangement of claim 19 wherein the predefined angle is about 45 degrees.

22. The thermal energy dissipating arrangement of claim 19 wherein the predefined angle is about 15 degrees.

23. The thermal energy dissipating arrangement of claim 19 wherein the predefined angle is about zero degrees such that the plane defined by the semiconductor junction substantially bisects the thermal energy dissipating medium defining the opening.

24. The thermal energy dissipating arrangement of claim 19 wherein the thermally conductive medium is formed of a material having a thermal conductivity of at least 50 W/mK.

25. The thermal energy dissipating arrangement of claim 19 wherein the thermally conductive medium is formed of a material having a thermal conductivity of at least 200 W/mK.

26. The thermal energy dissipating arrangement of claim 19 wherein the thermal energy dissipating medium comprises one of a sheet, strip and ring of thermally conductive material,

and wherein the opening defined through the length of the thermally conductive medium is defined through the one of the sheet, strip and ring of the thermally conductive material.

27. The thermal energy dissipating arrangement of claim 26 wherein the thermally conductive material comprises one or more of copper (Cu), Aluminum (Al), Gold (Au), Silver (Au), Magnesium (Mg), Tin (Sn), Zinc (Zn), Tungsten (W) and Beryllium (Be).

28. The thermal energy dissipating arrangement of claim 27 wherein the one of the sheet, strip and ring of the thermally conductive material defines a plurality of openings therethrough,

and wherein each of the plurality of openings is sized to receive in physical, thermally conductive contact a different one of a corresponding plurality of the LEDs therein.

29. The thermal energy dissipating arrangement of claim 19 wherein the thermal energy dissipating medium is separate from, and is not connected to, the mounting surface.

30. The thermal energy dissipating arrangement of claim 19 wherein the thermal energy dissipating medium is electrically isolated from the LED circuit.

31. The thermal energy dissipating arrangement of claim 19 further comprising a high surface emissivity coating applied to one or more surfaces of the thermal energy dissipating medium.

32. The thermal energy dissipating arrangement of claim 19 wherein the thermal energy dissipating medium comprises a washer.

33. The thermal energy dissipating arrangement of claim 32 wherein the washer has a circular outer periphery such that the washer defines an annular ring between the opening and the outer periphery.

34. The thermal energy dissipating arrangement of claim 19 further comprising a thermally conductive medium interposed in an interface defined between the thermal energy dissipating medium and the exterior surface of the encapsulating material, the thermally conductive medium facilitating transfer of the thermal energy from the semiconductor device to the thermal energy dissipating medium.

35. The thermal energy dissipating arrangement of claim 19 wherein the thermally conductive medium comprises at least one of a thermally conductive grease and a thermally conductive bonding medium.

36. A thermal energy dissipating arrangement, comprising:

a light emitting diode (LED) including an LED circuit having a top portion and a bottom portion, the bottom portion mounted to a mounting surface and defining a semiconductor junction between two dissimilar semiconductor regions, the semiconductor junction defining a plane that is substantially parallel to the mounting surface, and an encapsulating material in physical contact with at least the top portion of the LED circuit and surrounding both the top portion and bottom portion of the LED circuit, and

a thermal energy dissipating medium having a length and a thickness that is less than the length, the thermal energy dissipating medium defining an opening through the length such that the thickness of the thermal energy dissipating medium defines a wall about a periphery of the opening, the opening sized to receive therethrough the LED such that the wall is in physical, thermally conductive contact with an exterior surface of the encapsulating material about the LED with the wall intersecting the plane defining the semiconductor junction about a periphery of the LED circuit, the thermally conductive medium absorbing thermal energy generated within the LED as a result of current flow through the semiconductor junction and rejecting the absorbed thermal energy to an ambient environment surrounding the thermally conductive medium.