Thermal Energy Dissipating Arrangement for a Light Emitting Diode

• US 20100252853A1
• Filed: 03/19/2010
• Published: 10/07/2010
• Est. Priority Date: 03/19/2009
• Status: Abandoned Application

• Current Assignee: CID Technologies LLC
• Original Assignee: CID Technologies LLC
• Inventors: Christy, Alexander C.
• Application Number:
  US12/728,011
• Publication Number:
  US 20100252853A1
• Time in Patent Office: Days
• US Class Current: 257/99
• 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 and LED mounting arrangement includes an LED and a thermally conductive sheet. The thermally conductive sheet has a top surface, a bottom surface and thickness therebetween defining an opening therethrough sized to receive therein the LED such that the thickness of the thermally energy dissipating medium defining the opening is in physical, thermally conductive contact with an exterior surface of the at least one side portion of the encapsulating material of the LED. The thickness defining the opening absorbs thermal energy generated within the LED as a result of current flow through the LED circuit, and the thermal energy dissipating medium rejects the absorbed thermal energy to an ambient environment surrounding the thermal energy dissipating medium through a surface area of the thermal energy dissipating medium defined by the combination of the top surface, the bottom surface and an outer periphery thereof.

Claims

1. A thermal energy dissipating arrangement for a light emitting diode (LED), comprising:

an LED including an LED circuit having a top surface from which radiation is emitted in response to current flow through the LED circuit and an opposite bottom surface, and encapsulating material surrounding the LED circuit, the encapsulating material defining a top portion opposite the top surface of the LED circuit, a bottom portion opposite the bottom surface of the LED circuit and at least one side portion extending between the bottom portion and the top portion, and

a thermal energy dissipating medium having a top surface, a bottom surface and thickness therebetween defining an opening therethrough sized to receive therein the LED such that the thickness of the thermal energy dissipating medium defining the opening is in physical, thermally conductive contact with an exterior surface of the at least one side portion of the encapsulating material of the LED, the top and bottom surfaces of the thermal energy dissipating medium each defining a length that is greater than the thickness and that extends radially away from the opening to an outer periphery,

wherein the thickness of the thermally conductive medium defining the opening and in contact with the exterior surface of the at least one side portion of the encapsulating material of the LED absorbs thermal energy generated within the LED as a result of current flow through the LED circuit,

and wherein the thermal energy dissipating medium rejects the absorbed thermal energy to an ambient environment surrounding the thermal energy dissipating medium through a surface area of the thermal energy dissipating medium defined by the combination of the top surface, the bottom surface and the outer periphery.

2. The thermal energy dissipating arrangement of claim 1 wherein the thickness of the thermal energy dissipating medium is substantially uniform between the opening and the outer periphery thereof.

3. The thermal energy dissipating arrangement of claim 1 wherein the length of the top and bottom surfaces of the thermal energy dissipating medium is substantially constant about the outer periphery thereof.

4. The thermal energy dissipating arrangement of claim 1 wherein the length of the top and bottom surfaces of the thermal energy dissipating medium varies about the outer periphery thereof.

5. The thermal energy dissipating arrangement of claim 1 wherein the thermal energy dissipating medium comprises at least one of copper (Cu) and aluminum (Al).

6. 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).

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

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

9. The thermal energy dissipating arrangement of claim 1 wherein the LED further comprises a mounting surface to which the bottom surface of the LED circuit is mounted,

and wherein the thermal energy dissipating medium is separate from, and is not connected to, the mounting surface.

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

11. The thermal energy dissipating arrangement of claim 1 further comprising a high surface emissivity coating applied to one or more of the top surface of the thermal energy dissipating medium, the bottom surface of the thermal energy dissipating medium and the outer periphery of the thermal energy dissipating medium.

12. The thermal energy dissipating arrangement of claim 1 wherein an interface is defined between the opening defined through the thickness of the thermal energy dissipating medium and the at least one side of the encapsulating material of the LED,

and further comprising a thermally conductive medium interposed in the interface, the thermally conductive medium facilitating transfer of the thermal energy from the LED to the thermal energy dissipating medium.

13. The thermal energy dissipating arrangement of claim 12 wherein the thermally conductive medium comprises at least one of a thermally conductive grease and a thermally conductive bonding medium.

14. The thermal energy dissipating arrangement of claim 1 wherein the LED circuit defines a semiconductor junction between the top and bottom surfaces thereof across which the current flows through the LED circuit, the semiconductor junction defining a plane that is substantially parallel with the top and bottom surfaces of the LED circuit.

15. The thermal energy dissipating arrangement of claim 14 wherein the thickness of the thermal energy dissipating medium is substantially aligned with the plane defined by the semiconductor junction of the LED circuit.

16. The thermal energy dissipating arrangement of claim 14 wherein the thickness of the thermal energy dissipating medium defining the opening intersects an angle of less than or equal to a predefined angle relative to the plane defined by the semiconductor junction of the LED circuit.

17. The thermal energy dissipating arrangement of claim 16 wherein the predefined angle is about 60 degrees.

18. The thermal energy dissipating arrangement of claim 16 wherein the predefined angle is about 45 degrees.

19. The thermal energy dissipating arrangement of claim 16 wherein the predefined angle is about 15 degrees.

20. The thermal energy dissipating arrangement of claim 16 wherein the predefined angle is about zero degrees such that the plane defined by the semiconductor junction of the LED circuit substantially bisects the thickness of the thermal energy dissipating medium.