HEAT DISSIPATION DEVICE FOR LED CHIPS

• US 20090095959A1
• Filed: 12/27/2007
• Published: 04/16/2009
• Est. Priority Date: 10/10/2007
• Status: Active Grant

• Current Assignee: Foxconn Technology Co., Ltd., Fuzhun Precision Industry Company Limited (Foxconn Technology Co., Ltd.)
• Original Assignee: Foxconn Technology Co., Ltd., Fuzhun Precision Industry Company Limited (Foxconn Technology Co., Ltd.)
• Inventors: ZHOU, ZHI-YONG, DING, QIAO-LI, LAI, CHENG-TIEN
• Granted Patent: US 7,982,225 B2
• Time in Patent Office: Days
• US Class Current: 257/79
• 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 29/51 using condensation or evaporation of a fluid, e.g. heat pipes
• CPC Class Codes: F21V 29/75 with fins or blades having different shapes, thicknesses or spacing
• CPC Class Codes: F21V 29/763 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: F28D 15/0233 the conduits having a particular shape, e.g. non-circular cross-section, annular F28D15/0241, F28D15/0266 take precedence
• CPC Class Codes: F28F 3/02 Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations F28F3/08 takes precedence
• CPC Class Codes: H01L 23/427 Cooling by change of state, e.g. use of heat pipes by liquefied gas H01L23/445
• 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

Abstract

A heat dissipation device for removing heat from LED chips includes a heat sink and a plurality of substrates. The heat sink comprises a base plate. A plurality of fins extends upwardly from the base plate. The substrates each have a unidirectional heat transfer and are attached to a bottom face of the heat sink. Each of the substrates defines a first wall on which The LED chips are mounted and a second wall coupled to the heat sink. The substrates only transfer heat from the first wall to the second wall and restrict the heat transfer in a reverse direction. When the LED chips generate heat, the heat is transferred to the fins of the heat sink via the unidirectional substrates to lower temperature of the LED chips.

Claims

1. A heat dissipation device adapted for removing heat from LED chips, comprising:

a heat sink comprising a base plate which defines a first surface and a second surface opposite to the first surface, and a plurality of fins formed on the second surface of the base plate; and

a plurality of substrates of unidirectional heat transfer being attached to the first surface of the heat sink, each of the substrates defining a first wall on which the LED chips are mounted and a second wall coupled to the heat sink, the substrates only transferring heat from the first wall to the second wall and restricting heat transfer in a reversed direction;

wherein when the LED chips generate heat, the heat is transferred to the fins via the unidirectional substrates to lower temperature of the LED chips.

2. The heat dissipation device as claimed in claim 1, wherein each of the substrates is a plate-shaped vapor chamber and provided with a capillary wick therein.

3. The heat dissipation device as claimed in claim 2, wherein the capillary wick in the each of the substrates is a plurality of fine grooves defined in a lengthwise direction of the casing, a fine-mesh wick, or a layer of sintered metal/ceramic powders only formed on an inner side of the first wall and away from the second wall.

4. The heat dissipation device as claimed in claim 3, wherein the each of the substrates is half filled with working liquid which is just enough to submerge the capillary wick adjacent to the first wall when the first wall faces downwardly toward the ground.

5. The heat dissipation device as claimed in claim 1, wherein the fins extend from the second surface of the base plate and can be constructed in various configurations to maximize heat-exchanged area of the heat sink.

6. A heat dissipation device adapted for removing heat from LED chips, comprising:

a finned heat sink comprising a base plate;

a plurality of substrates each comprising a casing which is half filled with working liquid and has a first wall on which the LED chips are mounted and a second wall in contact with the base plate of the heat sink;

wherein each of the substrates is provided with a capillary wick which consists of a plurality of fine grooves defined in a lengthwise direction of the casing, a fine-mesh wick, or a layer of sintered metal/ceramic powders only formed on an inner side of the first wall and away from the second wall, and the working liquid which is just enough to submerge the capillary wick adjacent to the first wall when the first wall faces downwardly toward the ground.

7. The heat dissipation device as claimed in claim 6, wherein the substrates each are a plate-shaped vapor chamber, and the second surfaces of the substrates are coupled to the base plate of the heat sink by means of one of soldering and adhering.

8. The heat dissipation device as claimed in claim 6, wherein the base plate defines a first surface coupled with the second surface of the substrates and a second surface opposite the first surface.

9. The heat dissipation device as claimed in claim 8, wherein a plurality of fins extend from the second surface of the base plate and can be constructed in various configurations to maximize heat-exchanged area of the heat sink.

10. An LED assembly comprising:

a heat sink having a plurality of fins;

a plurality of plate-shaped vapor chambers attached to the heat sink; and

a plurality of LED chips thermally connected to the vapor chambers;

wherein the vapor chambers allow heat generated by the LED chips to be transferred to the heat sink to be dissipated to air via the vapor chambers, while the vapor chamber inhibit heat in the heat sink to be transferred to the LED chips via the vapor chambers.