US20070102147A1

US20070102147A1 - Heat dissipation apparatus and method for manufacturing the same

Info

Publication number: US20070102147A1
Application number: US11/309,674
Authority: US
Inventors: Chun-Yi Chang
Original assignee: Hon Hai Precision Industry Co Ltd
Current assignee: Hon Hai Precision Industry Co Ltd
Priority date: 2005-11-04
Filing date: 2006-09-08
Publication date: 2007-05-10
Also published as: CN1959967A

Abstract

An exemplary heat dissipation apparatus includes a base member and a number of cooling fins. Each of the cooling fins includes a main part and a foot part embedded in the base member, the foot part includes a first portion extending from the main part in the extension direction of the main part and at least one second portion extending at an angle from the first portion. The heat dissipation apparatus has a high heat dissipation efficiency.

Description

DESCRIPTION

1. Technical Field
The present invention relates generally to heat dissipation apparatuses and, more particularly, to a heat dissipation apparatus having improved heat dissipation efficiency used in an electronic device and a method for manufacturing the heat dissipation apparatus.
2. Discussion of Related Art
With the development of electronic science, operational frequencies of electronic components such as CPUs have become higher and higher, and as a result more energy is consumed and more heat is generated. As a result, it has become necessary to use a powerful heat dissipation device to dissipate the heat generated by the electronic components.
A typical heat dissipation apparatus generally includes a base and a number of cooling fins attached to the base. The base and the cooling fins can be made of a metal having high heat conductivity. Such metal can be, for example, copper, aluminium, etc. Advantageously, the base is made of a highly heat-conductive material such as copper, and the cooling fins are made of aluminium which can be easily processed to form a variety of shapes.
Such devices are usually disposed on a heat source for dissipating heat generated by the heat source through a combination of heat conduction and convection. Firstly, heat generated by the heat source is conducted to the atmosphere at a surface of the device by conduction; secondly, the heat dissipates into atmosphere by convection.
However the highly heat-resistant interfaces between the base and the cooling fins make the heat resistance of the heat dissipation apparatus relatively high, and heat dissipation efficiency of the heat dissipation device is therefore unsatisfactory.
Thus, there is a desire to develop a heat dissipation apparatus that has a low heat resistance between the base and the cooling fins, so as to improve the heat dissipation efficiency.

SUMMARY

In one embodiment, a heat dissipation apparatus includes a base member and a number of cooling fins. Each of the cooling fins includes a main part and a foot part embedded in the base member, the foot part includes a first portion extending from the main part in the extension direction of the main part (i.e., forming a continuation of the main body) and at least one second portion extending at an angle from the first portion.
In one embodiment, a method for manufacturing a heat dissipation apparatus, the method comprising the steps of: providing a base member and a plurality of cooling fins each having a main part and a foot part, the foot part including a first portion extending from the main part in the extension direction of the main part and a second portion extending at an angle from the first portion; defining a number of grooves on the base member in a manner so as conform to a shape of the foot parts of the cooling fins; and pressing the foot parts of the cooling fins into the corresponding grooves at a high temperature and a high pressure.
This and other features and advantages of the present invention as well as the preferred embodiments thereof and a heat dissipation apparatus and techniques for fabricating heat dissipation apparatus in accordance with the invention will become apparent from the following detailed description and the descriptions of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present apparatus and method can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present apparatus and method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views
FIG. 1 is a schematic, cross sectional schematic view of a heat dissipation apparatus in accordance with a first preferred embodiment;
FIG. 2 is a schematic, cross sectional view of the heat dissipation apparatus disposed on a heat source;
FIG. 3 is a schematic, cross sectional view of a heat dissipation apparatus in accordance with a second preferred embodiment;
FIG. 4 is a schematic, cross sectional view of a heat dissipation apparatus in accordance with a third preferred embodiment;
FIG. 5 is a schematic, cross sectional view of a heat dissipation apparatus in accordance with a fourth preferred embodiment;
FIG. 6 is a flow chart of a method for manufacturing a heat dissipation apparatus in accordance with another preferred embodiment; and
FIG. 7 is a schematic, cross sectional view of a base member for manufacturing the heat dissipation apparatus.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to FIG. 1, a heat dissipation apparatus 10 in accordance with the first preferred embodiment includes a base member 12 and a number of cooling fins 14. Each of the cooling fins 14 includes a main part 141 and a foot part 142 embedded in the base member 12 by using a process such as, for example, hot pressing and metallurgical means. such as, for example, placing the cooling fins 14 in liquid metal and then cooling the liquid to form the base member 12 with the cooling fins 14 embedded therein. Each foot part 142 includes a first portion 143 and a second portion 144. The first portion 143 extends straightly from the main part 141 along a longitudinal extension direction of the main part 141. The second portion 144 extends at an angle from the first portion 143. Thus, the first portion 143 and the second portion 144 form an obtuse angle to each other. The base member 12 and the cooling fins 14 are made of a metal or an alloy having high heat conductivity, such as copper, aluminium or copper-aluminium alloy.
Referring to FIG. 2, the heat dissipation apparatus 10 can be used for dissipating heat from a heat source 16. The heat source 16 is an electronic component such as a microprocessor. When the heat dissipation apparatus 10 is disposed on the heat source 16, heat generated in the heat source 16 is conducted to the main part 141 of the heat dissipation apparatus 10 through the foot part 142 and is dispersed into the ambient air. In the preferred embodiment, that the foot part 142 is inserted into the base member 12 using a process such as, for example, hot pressing, improves a contact area between the base member 12 and the foot part 142, and heat resistance between the base member 12 and the foot part 142 is decreased as a result.
Referring to FIG. 3, a heat dissipation apparatus 20 in accordance with a second embodiment is similar to that of the first embodiment except that each foot part 242 is composed of a first portion 243 and a second portion 244 extending perpendicularly to the first portion 243 so as to form “L” shaped cooling fins.
Referring to FIG. 4, a heat dissipation apparatus 30 in accordance with a third embodiment is similar to that of the first embodiment except that each foot part 342 includes a first portion 343 and a second portion 344 perpendicular to the first portion 343. The first portion 343 of each foot part 342 is connected to a center of the second portion 344 so as to form inverted “T” shaped cooling fins.
Referring to FIG. 5, the heat dissipation apparatus 40 in accordance with a fifth embodiment shown is similar to that of the second embodiment except that a base member 42 defines a vapor chamber 422 therein and a number of cooling fins 44 extending from the base member with a portion of each cooling fin being embedded in an upper portion of the base member 42 using a process such as, for example, hot pressing. The vapor chamber 422 contains a fluid 424 for facilitating heat conduction evenly from the base member 42 to the cooling fins 44. The fluid 424 can be a low boiling point fluid such as alcohol, acetone and ammonia, a high boiling point fluid such as water or any combination thereof. In order to decrease the boiling point of the fluid 424, the vapor chamber 422 should preferably be vacuumized to a pressure in the range from 10-3 Pa to 10-2 Pa.
In use, the base member 42 works as a heat pipe, i.e., the fluid 424 in the vapor chamber 422 is vaporized after absorbing heat generated from a heat source (not shown), the vapor flows from one end of the vapor chamber 422 to another end and discharges heat quickly. Thus, the heat is evenly transferred to the upper portion of the base member 42 and is conducted to the cooling fins 44 uniformly.
The heat dissipation apparatus in accordance with the aforementioned embodiments can be made by the following method. Take the heat dissipation apparatus 20 for example, referring to FIG. 6 and FIG. 7, the method includes the steps of:

- Step 1, providing a base member and a number of cooling fins each having a foot part 242 at an extremity thereof, wherein the foot part 242 includes a first portion 243 and a second portion 244 perpendicular to the first portion 242;
- Step 2, defining a number of grooves on the base member in a manner so as conform to a shape of the foot part 242 of the cooling fins; and
- Step 3, pressing the foot parts 242 of the cooling fins into the grooves 222 at a high temperature and a high pressure.

In step 1, each of the cooling fins includes a main part extending from the first portion of the foot part. The base member and the cooling fins are made of a material having high heat conductivity such as copper, aluminium, or copper-aluminium alloy.
In step 2, the grooves are configured for receiving the foot part 242. In order to increase the contact area between the foot parts 242 and the base member, the grooves are shaped so as to tightly accommodate the foot parts 242. Referring now to FIG. 7, each of the grooves 222 includes a first space 224 and a second space 226. The first space 224 is used for receiving the first potion 243. The second space 226 is used for receiving the second portion 244. The grooves 222 can be made by cutting or electrostatic discharging process. A size of the grooves should be less than that of the foot part 242, and preferably the size of the grooves should be approximately 0.2% to 5% less than that of the foot part 242.
In step 3, the temperature can be in a range from 500 to 600 degrees Celsius. Preferably, the pressure should be in the range from 600 to 1200 kilo-Newtons/metre2. This step can be performed by stamping/pressing. That is, the cooling fins 54 can be stamped into the grooves from the side surface of the base member 52 using a stamper. At such a high temperature and under such a high pressure, the atoms on the surface of the cooling fins and the grooves mix across the gap between the cooling fins and the grooves thus form an copper-aluminium alloy layer between the base member and the cooling fins.
The heat dissipation apparatus 20 can also be manufactured by using a metallurgical means, such as, for example, melting a metal material of the base member to a liquid in a mold and then inserting the cooling fins into the liquid, cooling the liquid and the cooling fins thereby obtaining the heat dissipation apparatus 20. Alternatively, a number of grooves are formed on the base member in a manner so as conform to a shape of the foot part 242 of the cooling fins, a mold is disposed on the base member, the mold and the grooves cooperatively define a number of chambers having the shape of the cooling fins, then a liquid of the metal material of the cooling fins is placed in the chambers, when the liquid is cooled the heat dissipation apparatus 20 is obtained.
Finally, it is to be understood that the above-described embodiments are intended to illustrate rather than limit the invention. Variations may be made to the embodiments without departing from the spirit of the invention as claimed. The above-described embodiments illustrate the scope of the invention but do not restrict the scope of the invention.

Claims

1. A heat dissipation apparatus comprising:

a base member and a plurality of cooling fins, each of the cooling fins comprising a main part and a foot part embedded in the base member, the foot part comprising a first portion extending from the main part in the extension direction of the main part and at least one second portion extending at an angle from the first portion.

2. The heat dissipation apparatus as claimed in claim 1, wherein the second section extends so as to be perpendicular to the first portion.

3. The heat dissipation apparatus as claimed in claim 1, wherein the at least one second portion comprises two opposite second portions extending from the first portion.

4. The heat dissipation apparatus as claimed in claim 1, wherein the base member comprises a phase change chamber.

5. The heat dissipation apparatus as claimed in claim 4, wherein the phase change chamber contains a cooling fluid therein.

6. The heat dissipation apparatus as claimed in claim 5, wherein the cooling fluid is selected from the group consisting of: ammonia, alcohol, acetone, water and any combination thereof.

7. The heat dissipation apparatus as claimed in claim 4, wherein a pressure in the phase change chamber is in the range from 10-3 Pa to 10-2 Pa.

8. The heat dissipation apparatus as claimed in claim 1, wherein a material of the base member and the cooling fins is selected from the group consisting of: copper, aluminium and copper-aluminium alloy.

9. The heat dissipation apparatus as claimed in claim 1, wherein a copper-aluminium alloy layer is formed between the cooling fins and the base member.

10. A method for manufacturing a heat dissipation apparatus, the method comprising the steps of:

providing a base member and a plurality of cooling fins each having a main part and a foot part, the foot part comprising a first portion extending from the main part in the extension direction of the main part and a second portion extending at an angle from the first portion;

defining a plurality of grooves on the base member in a manner so as conform to a shape of the foot parts of the cooling fins; and

pressing the foot parts of the cooling fins into the corresponding grooves at a high temperature and a high pressure.

11. The method as claimed in claim 10, wherein the temperature is in the range from 500° C. to 600° C.

12. The method as claimed in claim 10, wherein the pressure is in the range from 600 to 1200 kilo-Newtons/metre2.

13. The method as claimed in claim 10, wherein the pressing step is performed using a stamper.

14. A heat dissipation apparatus comprising:

a base member comprising a phase change member defined therein, the phase change member containing a cooling fluid therein; and

a plurality of cooling fins extending from the base member.

15. The heat dissipation apparatus as claimed in claim 14, wherein the cooling fluid is selected from the group consisting of: ammonia, alcohol, acetone, water and any combination thereof.

16. The heat dissipation apparatus as claimed in claim 14, wherein a pressure in the phase change chamber is in the range from 10-3 Pa to 10-2 Pa.