Abstract:
A combination heat-transfer plate member for use with a heat sink to dissipate heat from a CPU is disclosed having a flat graphite base member and two metal sheet members respectively bonded to the top and bottom sides of the flat graphite base member.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a heat-transfer plate member for use with a heat sink to dissipate heat from a CPU and more particularly, to a combination heat-transfer plat member, which is comprised of a flat graphite base member and two metal sheet members respectively bonded to the top and bottom sides of the flat graphite base member. 
         [0003]    2. Description of the Related Art 
         [0004]    Referring to  FIGS. 1 and 2 , a heat-transfer plate member  3  is shown sandwiched between a CPU  1  and a heat sink  2  for transferring heat from the CPU  1  to the heat sink  2  for dissipation into the outside open air during the operation of the CPU  1 . The heat-transfer plate member  3  is a solid copper plate. This design of heat-transfer plate member  3  has the following drawbacks: 
         [0005]    1. Because the heat-transfer plate member  3  is made of a solid copper plate, the material cost of the heat-transfer plate member  3  is high. 
         [0006]    2. Because the coefficient of heat transfer of copper (402 W/MK) is lower than the coefficient of heat transfer (503 W/MK) of graphite, the heat transferring effect of this design of heat-transfer plate member  3  is not the best. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a combination heat-transfer plate member, which is inexpensive to manufacture and, provides a satisfactory heat transfer effect. To achieve this and other objects of the present invention, the combination heat-transfer plate member comprises a flat graphite base member, and two metal sheet members respectively bonded to the top and bottom sides of the flat graphite base member with a bonding glue. Preferably, the metal sheet members include one copper sheet member and one aluminum sheet member. The bonding glue can be obtained from silicone rubber adhesive or acrylic rubber adhesive. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an exploded view showing an application example of a heat-transfer plate member according to the prior art. 
           [0009]      FIG. 2  is a sectional assembly view of  FIG. 1 . 
           [0010]      FIG. 3  is an exploded view of a combination heat-transfer plate member in accordance with a first embodiment of the present invention. 
           [0011]      FIG. 4  is an elevational view of the combination heat-transfer plate member in accordance with the first embodiment of the present invention. 
           [0012]      FIG. 5  is a sectional view in an enlarged scale of the combination heat-transfer plate member in accordance with the first embodiment of the present invention. 
           [0013]      FIG. 6  is a sectional view of a combination heat-transfer plate member in accordance with a second embodiment of the present invention. 
           [0014]      FIG. 7  is a sectional view of a combination heat-transfer plate member in accordance with a third embodiment of the present invention. 
           [0015]      FIG. 8  is a sectional view of a combination heat-transfer plate member in accordance with a fourth embodiment of the present invention. 
           [0016]      FIG. 9  is a sectional view of a combination heat-transfer plate member in accordance with a fifth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0017]    Referring to  FIGS. 3˜5 , a combination heat-transfer plate member sunscreen assembly in accordance with a first embodiment of the present invention is shown comprising a flat graphite base member  10 , a first metal sheet member  11  covered on one side of the flat graphite base member  10 , a second metal sheet member  12  covered on the other side of the flat graphite base member  10  opposite to the first metal sheet member  11 , and a bonding glue  13  applied to one side of the first metal sheet member  11  and one side of the second metal sheet member  12  and the two opposite sides of the flat graphite base member  10  to fixedly secure the first metal sheet member  11  and the second metal sheet member  12  to the two opposite sides of the flat graphite base member  10 . 
         [0018]    According to this embodiment, the first metal sheet member  11  is an aluminum sheet member thickness below 0.1 mm, and the second metal sheet member  12  is a copper sheet members of thickness below 0.1 mm. The bonding glue  13  can be silicone rubber adhesive or acrylic rubber adhesive. 
         [0019]      FIG. 6  shows a combination heat-transfer plate member in accordance with a second embodiment of the present invention. This embodiment is substantially similar to the aforesaid first embodiment with the exception that a heat-transfer powder  14  is added to the bonding glue  13  to enhance the heat transferring power of the combination heat-transfer plate member. The heat-transfer powder  14  can be graphite powder, carbon powder, copper powder, silver powder, nickel powder, or titanium powder. 
         [0020]      FIG. 7  shows a combination heat-transfer plate member in accordance with a third embodiment of the present invention. According to this embodiment, the heat-transfer metal plate member comprises a flat graphite base member  10 , a metal sheet member  12  covered on one side of the flat graphite base member  10 , and a bonding glue  13  applied to one side of the flat graphite base member  10  and one side of the metal sheet member  12  to fixedly secure the metal sheet member  12  to the flat graphite base member  10 . 
         [0021]      FIG. 8  shows a combination heat-transfer plate member in accordance with a fourth embodiment of the present invention. This embodiment is substantially similar to the aforesaid first embodiment with the exception that the combination heat-transfer plate member of this fourth embodiment has a corrugated profile. 
         [0022]      FIG. 9  shows a combination heat-transfer plate member in accordance with a fourth embodiment of the present invention. This embodiment is substantially similar to the aforesaid first embodiment with the exception that the heat-transfer plat member of this fifth embodiment has a substantially U-shaped profile. 
         [0023]    As indicated above, a combination heat-transfer plate member in accordance with the present invention has the following benefits: 
         [0024]    1. Because the coefficient of heat transfer of copper (503 W/MK) of graphite is higher than the coefficient of heat transfer (402 W/MK) of copper, a combination heat-transfer plate member made according to the present invention is superior to a conventional solid heat-transfer plate member made out of copper or aluminum. 
         [0025]    2. During application of the combination heat-transfer plate member, the copper sheet member  12  and the aluminum sheet member are respectively kept in contact with the CPU and the heat sink so that the flat graphite base member  10  effectively absorbs heat energy from the CPU through the copper sheet member  12  and efficiently transfer absorbed heat energy to the heat sink through the aluminum sheet member  11 . 
         [0026]    3. Because the copper sheet member  12  has a thickness below 0.1 mm and because the material cost of aluminum and graphite is low, the manufacturing cost of the combination heat-transfer plate member is low. 
         [0027]    4. Because the aluminum sheet member  11  and the copper sheet member  12  are respectively bonded to the two opposite sides of the flat graphite base member  10 , the flat graphite base member  10  is well protected. Therefore, the combination heat-transfer plate member of the present invention has a mechanical strength similar to a heat-transfer plate member of pure copper. 
         [0028]    5. Because the flat graphite base member  10  is sandwiched between the aluminum sheet member  11  and the copper sheet member  12 , the combination heat-transfer plate member of the present invention can be stamped into any of a variety of curved shapes. 
         [0029]    Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention.