TRANSPARENT HEAT SPREADER FOR LEDS

• US 20100140655A1
• Filed: 02/26/2009
• Published: 06/10/2010
• Est. Priority Date: 02/26/2009
• Status: Active Grant

• Current Assignee: Bridgelux Incorporated
• Original Assignee: Bridgelux Incorporated
• Inventors: Shi, Wei
• Granted Patent: US 7,851,819 B2
• Time in Patent Office: Days
• US Class Current: 257/99
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/642 characterized by the shape
• CPC Class Codes: H01L 33/644 in intimate contact or integrated with parts of the device other than the semiconductor body

Abstract

A heat spreader for an LED can include a thermally conductive and optically transparent member. The bottom side of the heat spreader can be configured to attach to a light emitting side of the LED. The top and/or bottom surface of the heat spreader can have a phosphor layer formed thereon. The heat spreader can be configured to conduct heat from the LED to a package. The heat spreader can be configured to conduct heat from the phosphors to the package. By facilitating the removal of heat from the LED and phosphors, more current can be used to drive the LED. The use of more current facilitates the construction of a brighter LED, which can be used in applications such as flashlights, displays, and general illumination. By facilitating the removal of heat from the phosphors, desired colors can be better provided.

Claims

1. A heat spreader for an LED, the heat spreader comprising a thermally conductive and optically transparent member though which light from the LED passes and which is configured to facilitate heat flow away from the LED.

2. The heat spreader as recited in claim 1, wherein the thermally conductive and optically transparent member has a thermal conductivity higher than approximately 5 W/mK.

3. The heat spreader as recited in claim 1, wherein the thermally conductive and optically transparent member has a thermal conductivity of approximately 35 W/mK.

4. The heat spreader as recited in claim 1, wherein the thermally conductive and optically transparent member comprises sapphire.

5. The heat spreader as recited in claim 1, wherein the thermally conductive and optically transparent member is configured so as to define at least one lens.

6. The heat spreader as recited in claim 1, wherein the thermally conductive and optically transparent member is configured so as to define a global lens for a plurality of LED dice.

7. The heat spreader as recited in claim 1, wherein the thermally conductive and optically transparent member is configured so as to define a plurality of individual lenses.

8. The heat spreader as recited in claim 1, wherein the bottom side of the thermally conductive and optically transparent member is configured to attach to a light emitting side of the LED die.

9. The heat spreader as recited in claim 1, wherein a top side of the thermally conductive and optically transparent member has a phosphor layer formed thereon.

10. The heat spreader as recited in claim 1, wherein the thermally conductive and optically transparent member is configured to conduct heat from the LED to a package substrate.

11. The heat spreader as recited in claim 1, wherein the then ally conductive and optically transparent member is configured to conduct heat from phosphors to a package substrate.

12. The heat spreader as recited in claim 1, wherein the substrate is configured to enhance a temperature uniformity of phosphors.

13. An LED assembly comprising:

at least one LED die;

a package to which the LED die/dice are attached; and

a heat spreader comprising a thermally conductive and optically transparent member though which light from the LED die/dice passes and which is configured to facilitate heat flow away from the LED die/dice.

14. The LED assembly as recited in claim 13, wherein the LED die/dice are attached to the bottom side of the heat spreader.

15. The LED assembly as recited in claim 13, wherein the heat spreader is configured to conduct heat from the LED die/dice to the package.

16. The LED assembly as recited in claim 13, further comprising a phosphor layer formed upon the heat spreader.

17. The LED assembly as recited in claim 13, further comprising a phosphor layer formed upon the heat spreader and wherein the heat spreader is configured to conduct heat from the phosphors to a package so as to enhance a temperature uniformity of phosphors.

18-26. -26. (canceled)