LED package with structure and materials for high heat dissipation

• US 20060091415A1
• Filed: 10/26/2005
• Published: 05/04/2006
• Est. Priority Date: 10/29/2004
• Status: Active Grant

• Current Assignee: LED Engin, Inc. (Ams-Osram AG)
• Original Assignee: Ledengin, Inc. (Ams-Osram AG)
• Inventors: Yan, Xiantao
• Granted Patent: US 7,772,609 B2
• Time in Patent Office: Days
• US Class Current: 257/99
• 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 33/60 Reflective elements
• CPC Class Codes: H01L 33/641 characterized by the materials

Abstract

LED packages are provided that include a material that is both thermally conductive and has a coefficient of thermal expansion that is matched to that of an LED. The material can be a ceramic such as aluminum nitride. The package has a body that includes a bottom surface and a cavity disposed into the body. The cavity has a floor for bonding to the LED so that the LED sits within the cavity. The thermally conductive material is disposed between the floor of the cavity and the bottom surface of the package. The body can be fabricated from a number of layers where the thermally conductive material is in a layer disposed between the floor and the bottom surface. The other layers of the body can also be fabricated from the thermally conductive material. A light emitting device is made by attaching the LED to the LED package.

Claims

1. A package for an LED comprising:

a body including

a cavity having a floor for bonding to an LED;

a bottom surface; and

a thermally conducting ceramic material disposed between the floor and the bottom surface and having a thermal conductivity greater than 14 W/m°

K.

2. The package of claim 1 wherein the thermally conducting ceramic material includes aluminum nitride.

3. The package of claim 1 wherein the thermally conducting ceramic material includes alumina.

4. The package of claim 1 wherein the thermally conducting ceramic material has a thermal conductivity greater than 150 W/m°

K.

5. The package of claim 1 wherein the thermally conducting ceramic material has a coefficient of thermal expansion less than 15 ppm/°

C.

6. The package of claim 1 wherein the thermally conducting ceramic material has a thickness in a range of about 0.2 mm to 0.4 mm.

7. The package of claim 1 wherein the body includes a thermal conduction layer between the floor of the cavity and the bottom surface, the thermally conducting ceramic material being disposed within the thermal conduction layer.

8. The package of claim 7 wherein the body includes two additional layers each formed of a thermally conductive material, the cavity being disposed through the two additional layers.

9. The package of claim 8 wherein each of the three layers includes aluminum nitride.

10. The package of claim 1 further comprising an electrically nonconductive central bonding pad disposed on the floor of the cavity.

11. The package of claim 1 wherein a sidewall of the cavity is optically reflective.

12. A package for an LED comprising:

a body including

a cavity having a floor for bonding to an LED;

a bottom surface; and

a thermally conductive material disposed between the floor and the bottom surface and having a thermal conductivity greater than 14 W/m°

K and a coefficient of thermal expansion less than 15 ppm/°

C.

13. The package of claim 12 wherein the thermally conductive material includes a ceramic material.

14. The package of claim 12 wherein the thermally conductive material includes aluminum nitride.

15. The package of claim 12 wherein the thermally conductive material has a thermal conductivity greater than 150 W/m°

K.

16. A light emitting device comprising:

a body including

a cavity having a floor for bonding to an LED,

a bottom surface, and

a thermally conducting ceramic material disposed between the floor and the bottom surface and having a thermal conductivity greater than 14 W/m°

K;

an LED bonded to the floor of the cavity; and

a luminescent material disposed over the LED.

17. The light emitting device of claim 16 wherein the thermally conducting ceramic material includes aluminum nitride.

18. The light emitting device of claim 16 wherein the thermally conducting ceramic material includes alumina.

19. The light emitting device of claim 16 wherein the thermally conducting ceramic material has a thermal conductivity greater than 150 W/m°

K.

20. The light emitting device of claim 16 wherein the thermally conducting ceramic material has a coefficient of thermal expansion less than 15 ppm/°

C.

21. The light emitting device of claim 16 further comprising a thermal insulating material disposed over the LED.