Direct cooling of LEDs

• US 7,235,878 B2
• Filed: 03/18/2005
• Issued: 06/26/2007
• Est. Priority Date: 03/18/2004
• Status: Active Grant

• Current Assignee: Phoseon Technology, Inc.
• Original Assignee: Phoseon Technology, Inc.
• Inventors: Anderson, Duwayne R., Owen, Mark D., Vlach, Francois
• Primary Examiner(s): Parekh; Nitin
• Application Number:
  US11/083,525
• Publication Number:
  US 20050253252A1
• Time in Patent Office: 830 Days
• Field of Search: 257/714, 257/81, 257/88, 257/433, 257/443, 257/680, 257/99
• US Class Current: 257/714
• CPC Class Codes: F21V 29/59 with forced flow of the coolant
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 23/473 by flowing liquids H01L23/4332, H01L23/4338 take precedence
• 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 33/648 the elements comprising fluids, e.g. heat-pipes

Abstract

A thermal management system is provided for semiconductor devices such as an LED array, wherein coolant directly cools the LED array. Preferably, the coolant may be selected, among other bases, based on its index of refraction relative to the index associated with the semiconductor device.

Claims

1. A thermal management system for cooling a semiconductor device, comprising:

a housing enclosing a semiconductor device with at least one channel formed in the housing adjacent to the semiconductor device, and

a coolant supply for directing a liquid coolant through the housing to flow through the at least one channel to directly cool a light emissive surface of the semiconductor device;

wherein the semiconductor device is a plurality of LEDs mounted on a substrate and in which the LEDs are located in the at least one channel so that the coolant flows to directly cool the LEDs; and

the LEDs are mounted to transmit light through a window in the housing,

the at least one channel being formed so as to be disposed between the window and the LEDs.

2. The thermal management system of claim 1, wherein the housing includes a further heat collection mechanism.

3. The thermal management system of claim 2, wherein the further heat collection mechanism includes at least one heat pipe connected to the substrate.

4. The thermal management system of claim 3, wherein the at least one heat pipe is bonded to the substrate and to a heat spreader.

5. The thermal management system of claim 2, wherein the further heat collection mechanism is cooled by the coolant.

6. The thermal management system of claim 1, wherein the housing includes a coolant supply flow chamber that receives the coolant from an inlet, the coolant supply chamber being in communication with the at least one channel so that coolant flows through the channel to directly cool the semiconductor device, and a discharge chamber in communication with the at least one channel through which the coolant flows out of the housing through an outlet.

7. The thermal management system of claim 1, wherein the housing forms plural flow channels through which coolant flows to directly cool multiple surfaces of the semiconductor device.

8. The thermal management system of claim 7, wherein plural flow channels are constructed and arranged to both directly cool the LEDs and indirectly cool the LEDs through the substrate.

9. The thermal management system of claim 1, wherein the coolant is a polar liquid.

10. The thermal management system of claim 1, wherein the coolant is an inert liquid.

11. The thermal management system of claim 10, wherein the inert liquid is one of a mineral, vegetable, or synthetic oil.

12. The thermal management system of claim 1, wherein the semiconductor device has a light-emitting face, and wherein a first optical coupling is provided for an interface formed by the face and the coolant.

13. The thermal management system of claim 12, further comprising optics, the optics disposed to form an interface between the coolant and the optics, wherein a second optical coupling is provided for the interface between the coolant and the optics.

14. The thermal management system of claim 13, wherein the first and second optical couplings are stepped with respect to indices of refraction.

15. A thermal management system for cooling an LED array, the LED array being configured for applications requiring relatively high optical power density applied at a working surface of a target for the purpose of illuminating and performing a material transformation in or of the target, the system comprising:

a selected liquid coolant,

a housing enclosing the LED array,

a coolant supply for directing the coolant through at least one or more channels in the housing to directly cool light emissive surface of LEDs in the LED array, the LED array being disposed in the one or more channels the LED array;

whereby the direct cooling enables the LED array to have an enhanced optical power density wherein the LEDs are mounted to transmit light through a window in the housing, the at least one channel being formed so as to be disposed between the window and the LEDs.

16. The thermal management system of claim 15, wherein the coolant is selected based on one or more factors, such factors including one or more of index of refraction;

thermal capacity;

thermal conductivity;

transparency to selected wavelength(s) of light;

performance under operating conditions expected for the system;

stability and performance; and

reactivity.

17. The thermal management system of claim 15, wherein the coolant and LED array form one or more interfaces and optical coupling is provided for at least one of such interfaces.