TREA

Heat sink and method for manufacturing the same

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Information

  • Patent Application
  • 20050150633
  • Publication Number
    20050150633
  • Date Filed
    January 09, 2004
    20 years ago
  • Date Published
    July 14, 2005
    19 years ago
Information
Abstract
A heat sink and a method for manufacturing a heat sink are described. A plate-like base is manufactured with a plurality of parallel grooves and a plurality of fins by an impact extrusion process. A high temperature heat treatment is performed to soften the plate-like base. The fins are positioned in corresponding grooves and an equal force is applied to both ends of the plate-like base so that the grooves are deformed and the fins are fixedly positioned. The method is simpler and significantly cheaper than that for conventional heat sinks.
Description
BACKGROUND OF THE INVENTION

1. Field of the Invention


The present invention relates to a heat sink and a method for manufacturing the same, and in particular to a heat sink and a method for manufacturing a heat sink that is easily manufactured, cheap and highly efficient in heat dissipation.


2. Description of Related Art


Referring to FIGS. 1 and 2, a conventional heat sink 1 is disclosed. The conventional heat sink 1 has a plate-like base 11 and a plurality of fins 12. The plate-like base 11 and plurality of fins 12 are manufactured by an impact extrusion process and can be made of copper. Then, thermal transfer adhesive is applied to the bottom of the fins 12 which are equidistantly separated and positioned on top surface of the plate-like base 11.


In addition, the plate-like base 11 and plurality of fins 12 can also be made of copper and aluminum, respectively. Compared with the heat sink made of copper in the prior art, the heat sink described above has less overall weight. However, when a plurality of fins 12 is connected to the plate-like base 11, each fin 12 must individually soldered to the top surface of the plate-like base 11 by solder 13.


No matter what the plate-like base 11 and a plurality of fins 12 are made of, it is time-consuming and expensive to connect the plate-like base 11 and a plurality of fins 12 by soldering.


Due to the desire for lightweight mobile electronic device, when the heat sink has less weight, it is not prone breaking during shipping. Although the conventional heat sink 1 is made of lightweight aluminum instead of the heavier copper, the weight of the conventional heat sink 1 cannot be decreased. However, the fins 12 are soldered to most of the area of the plate-like base 11 so that the weight of the conventional heat sink 1 fails to be significantly decreased.


Furthermore, the plate-like base 11 of the conventional heat sink 1 abuts against a heat-generating component 21. A fan (not shown) subsequently attached to the conventional heat sink 1 provides a cooling airflow. Because the fins 12 are equidistantly separated and positioned on the top surface of the plate-like base 11, the cooling airflow contacts the plate-like base 11 of the conventional heat sink 1. Then, part of the cooling airflow flows between fins 12 and another part of the cooling airflow flows in the opposite direction. Turbulent airflow thus occurs near the contact area of the fins 12 and the plate-like base 11 and generates a higher back pressure so that the fan provides less airflow and efficiency of heat dissipation is adversely impacted.


Thus, there is need to develop a heat sink and a method for manufacturing a heat sink.


SUMMARY OF THE DISCLOSURE

It is an object of the present invention to provide a heat sink and a method for manufacturing a heat sink that is easily manufactured, cheap and highly efficient in heat dissipation.


It is another object of the present invention to provide a method for manufacturing a heat sink made of different materials and that is lighter and highly efficient in heat dissipation.


It is another object of the present invention to provide a heat sink made of different materials and that is lighter and highly efficient in heat dissipation.


It is an object of the present invention to provide a heat sink and a method for manufacturing a heat sink. The method of the present invention includes manufacturing a plate-like base with a plurality of parallel grooves and a plurality of fins by an impact extrusion process, performing a high temperature heat treatment to soften the plate-like base, and positioning the fins to corresponding grooves and applying an equal force to both ends of the plate-like base so that the grooves are deformed and the fins are fixedly positioned.




BRIEF DESCRIPTION OF DRAWINGS

The present invention can be fully understood from the following detailed description and preferred embodiment with reference to the accompanying drawings, in which:



FIG. 1 is a perspective view of a conventional heat sink;



FIG. 2 is an enlarged partial view of the conventional heat sink indicated by arrow A of FIG. 1;



FIG. 3 is an exploded view of a heat sink in accordance with the present invention;



FIG. 4 is a perspective view of a heat sink in accordance with the present invention;



FIG. 5 is an enlarged partial view of the heat sink indicated by arrow A of FIG. 4;



FIG. 6 is a block diagram illustrating a heat sink according to one embodiment of the present invention; and



FIG. 8 is a block diagram illustrating a heat sink according to another embodiment of the present invention.




DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description is of the best presently contemplated modes of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating general principles of embodiments of the invention. The scope of the invention is best defined by the appended claims.



FIGS. 3-5 illustrate a heat sink 3 in accordance with one embodiment of the present invention. The heat sink 3 has a plate-like base 31 and a plurality of fins 32 positioned on the plate-like base 31. The plate-like base 31 has a central segment 311 and two flange segments 312. The two flange segments 312 correspond to and extend from both ends of the central segment 311 in the direction of arrow Y. The central segment 311 and the two flange segments 312 have their corresponding top surfaces and bottom surfaces. The top surfaces of the central segment 311 and the two flange segments 312 are in the same plane, and the bottom surfaces of the central segment 311 and the two flange segments 312 are also in the same plane. In addition, a length of the central segment 311 in the direction of arrow X is greater than that of the two flange segments 312. A plurality of parallel grooves 313 is located in the central segment 311 and the two flange segments 312. Further, each of the parallel grooves 313 is U-shaped and is adapted to receive the fins 32.


Referring to FIGS. 3 and 4, the length of the fins 32 is greater than that of the plate-like base 31 in the direction of arrow X. Thus, middle portions 321 of the fins 32 are only in contact with the plate-like base 31. However, two end portions 322 of the fins 32 are not in contact with the plate-like base 31, and there are thermal transfer channels 323 between two neighboring fins 31.


Thus, the central segment 311 of the plate-like base 31 abuts against a heat-generating component 42 of a circuit board 41. The two flange segments 312 of the plate-like base 31 are not in contact with two end portions 322 of the fins 32 so that the circuit board 41 is not in contact with the fins 32. When the heat-generating component 42 is in use, the central segment 311 of the plate-like base 31 conducts heat generated by the heat-generating component 42 and carries heat into the fins 32 of the two flange segments 312 and the plate-like base 31. Heat is thus vented away from the fins 32. To increase efficiency of heat dissipation, a fan (not shown) can be installed on the heat sink 3 and cooling airflow flows in the directions indicated by arrows in FIG. 4. After the cooling air is blowing at the fins 32, the cooling air is blown along the thermal transfer channels 323 between the fins 32 and is directed toward the two end portions 322 of the fins 32. Further, a part of cooling airflow flows through the bottom of the thermal transfer channels 323. Thus, a larger back pressure does not result to lessen the cooling airflow of the fan. The heat sink 3 of one embodiment of the present invention has an improved efficiency of heat dissipation.


Referring to FIGS. 3 and 6, a method of manufacturing the heat sink 3 is described as follows. In step 51, the plate-like base 31 is formed on the heat sink 3 by an impact extrusion process, and a plurality of parallel grooves 311 are formed by a stamping process. The plate-like base 31 and the fins 32 can be respectively made of copper and aluminum. In step 52, the plate-like base 31 is placed in a high temperature furnace and the temperature within the furnace is kept between 1000-1100° C. so that the plate-like base 31 is fully softened to relieve residual stress. In step 53, the fins 32 are respectively positioned into the parallel grooves 311 of the plate-like base 31 by a jig (not shown), and the plate-like base 31 is subjected to compressive forces as shown in FIG. 5 so that the parallel grooves 311 are deformed to grasp the fins 32. The plate-like base 31 and the fins 32 of the heat sink 3 are made of aluminum or copper.


Referring to FIG. 7, in Step 54, the plate-like base 31 is manufactured by powder metallurgy and the fins 32 are manufactured by an impact extrusion process. Because density of components made by powder metallurgy is less than that of aluminum or copper, the processing of softening the plate-like base 31 is shortened. Then, in step 55, the fins 32 can be positioned in the parallel grooves 311 of the plate-like base 31 and the plate-like base 31 is subjected to a compressive force.


Thus, advantages of the present invention are described in the following:


1. The manufacturing process is straightforward and has a low cost. The plate-like base 31 is formed on the heat sink 3 by an impact extrusion process, and a plurality of parallel grooves 311 is formed by a stamping process. The plate-like base 31 is placed in a high temperature furnace. The fins 32 are respectively positioned in the parallel grooves 311 of the plate-like base 31, and the plate-like base 31 is subjected to compressive forces. The parallel grooves 311 are deformed to grasp the fins 32. Thus, compared with the conventional method, the present invention provides a simplified method and is significantly cheaper.


2. The heat sink according to present invention has improved efficiency of heat dissipation. Since the parallel grooves 311 of the plate-like base 31 of the present invention abut against the heat-generating component 42, the two flange segments 312 of the plate-like base 31 are not in contact with two end portions 322 of the fins 32. Thus, there is a gap between the circuit board 41 and the fins 32. When the heat-generating component 42 is in use, the central segment 311 of the plate-like base 31 conducts heat generated by the heat-generating component 42 and carries heat into the fins 32 of the two flange segments 312 and the plate-like base 31. Heat is vented away from the fins 32 with the help of cooling air (a fan can be installed on the heat sink 3 to increase efficiency of heat dissipation). After the cooling air is blown onto the fins 32, the cooling air is blown along the thermal transfer channels 323 between the fins 32 and is directed toward the two end portions 322 of the fins 32. Further, a part of cooling airflow is flows through the bottom of the thermal transfer channels 323. Thus, a larger back pressure does not result to lessen the cooling airflow of the fan. The heat sink 3 of one embodiment of the present invention has a better efficiency of heat dissipation.


3. The heat sink is lightweight.


According to the present invention, the plate-like base 31 and the fins 32 of the heat sink 3 are respectively made of copper and aluminum. The present invention is able to meet the requirement of a light-weight of mobile electronic device. When the heat sink is lightweight, it is not prone to damage during transportation.


4. The material of which the plate-like base 31 and the fins 32 are made can be replaced if necessary.


5. There is no limitation of separation and height of the fins 32.


While the invention has been described with reference to the preferred embodiments, the description is not intended to be construed in a limiting sense. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as may fall within the scope of the invention defined by the following claims and their equivalents.

Claims
  • 1. A heat sink, comprising: a plate-like base, having a plurality of parallel grooves; and a plurality of fins, respectively positioned in the parallel grooves.
  • 2. The heat sink as claimed in claim 1, wherein the plate-like base and the fins are made of aluminum.
  • 3. The heat sink as claimed in claim 1, wherein the plate-like base and the fins are made of copper.
  • 4. The heat sink as claimed in claim 1, wherein the plate-like base has a central segment and two flange segments, and the two flange segments correspond to and extend from both ends of the central segment.
  • 5. The heat sink as claimed in claim 1, wherein the parallel grooves are U-shaped.
  • 6. The method of manufacturing a heat sink, the method comprising the steps of: manufacturing a plate-like base with a plurality of parallel grooves and a plurality of fins by an impact extrusion process; positioning the fins to corresponding grooves and applying an equal force to both ends of the plate-like base so that the grooves are deformed and the fins are fixedly positioned.
  • 7. The method as claimed in claim 6, wherein the plate-like base and the fins are made of aluminum.
  • 8. The method as claimed in claim 6, wherein the plate-like base and the fins are respectively made of copper and aluminum.
  • 9. The method as claimed in claim 6, wherein the plate-like base and the fins are manufactured by powder metallurgy.
  • 10. The method as claimed in claim 6, wherein the plate-like base is subjected to a high temperature heat treatment to soften the plate-like base.