Abstract:
A computer cooling apparatus is provided. The computer cooling apparatus includes a case, a fan, a CPU (central processing unit), and a heat radiating device. The case has an air outlet formed in one side. The fan is formed at another side of the case to suction external air. The CPU is installed in the case. The heat radiating device radiates heat generated from the CPU. The fan and the air outlet are formed in mutually opposite positions, and direct a flow of the external air suctioned by the fan in one direction.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a computer cooling apparatus, and more particularly, to a personal computer cooling apparatus capable of simultaneously cooling a central processing unit (CPU) and an inside of a computer case using one fan, and improving air flow inside a computer case to increase cooling performance of other chip sets installed inside the computer case as well as the CPU. 
         [0003]    2. Description of the Related Art 
         [0004]    Generally, electronic equipment is usually air-cooled. This method generally uses heatsinks that are formed on a common metal plate to increase a radiating area. Today, heat pipe is widely used as a cooling device. The heat pipe radiates heat generated from a heat source to the outside. 
         [0005]    A related art CPU generates heat of about 115 W. However, a CPU generating heat of nearly 135 W will soon be manufactured. Therefore, cooling performance of CPUs is becoming more and more important. 
         [0006]    Because calorific values of various chip sets as well as the CPU are increasing, it is important to cool the entire inside of the computer case as well as the CPU. 
         [0007]      FIG. 1  is a schematic perspective view illustrating a computer cooling apparatus according to the related art. 
         [0008]    Referring to  FIG. 1 , a computer cooling apparatus according to the related art includes a case (not shown) including various components of a computer, a system fan (not shown) formed at one side of the case, a mainboard  1  connected to the case, a CPU  2  mounted on the mainboard  1 , and a heat radiating device  3  for radiating heat generated from the CPU  2 . 
         [0009]    The heat radiating device  3  includes a plate  4  contacting an upper surface of the CPU  2  to receive the heat, a heat pipe  5  connected to the plate  4  to receive the heat, a heatsink  6  connected to the heat pipe  5  to receive the heat, and a fan  7  disposed above the heatsink  6  to radiate the heat of the heatsink  6 . 
         [0010]    Thus, the heat generated from the CPU  2  is transferred to the heatsink  6  through the plate  4  and the heat pipe  5 . The heat transferred to the heatsink  6  is radiated inside the computer case by the fan  7 . The heat radiated inside the computer case by the fan is radiated outside the computer by the system fan (not shown). 
         [0011]    However, in the computer cooling apparatus according to the related art as described above, an auxiliary fan  7  for cooling the CPU  2  is used in addition to the system fan. Therefore, a vortex is generated inside the computer case due to heated air emitted by fan  7  mixing with air blown by the system fan. As a result, the heated air is not smoothly expelled from the computer case, thereby decreasing the cooling performance of not only the CPU  2 , but the interior of the computer case as well. 
         [0012]    Also, only the heated air inside the computer case is expelled, but other chip sets beside the CPU is not directly cooled. 
         [0013]    In the heat radiating device  3  of the CPU according to the related art, the auxiliary fan  7  is vertically formed, increasing the size of the computer body. 
         [0014]    The auxiliary fan  7  that is used for cooling the CPU  2  increases production cost. 
       SUMMARY OF THE INVENTION 
       [0015]    Accordingly, the present invention is directed to an air conditioner that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
         [0016]    An object of the present invention is to provide a computer cooling apparatus for simultaneously cooling a CPU and an inside of a computer case using one fan to improve cooling performance and reduce production cost. 
         [0017]    Another object of the present invention is to provide a computer cooling apparatus in which air inside computer case flows in one direction to smoothly expel the air from inside. 
         [0018]    A further object of the present invention is to provide a computer cooling apparatus for simultaneously cooling other chip sets inside a computer case as well as a CPU improve cooling efficiency in a process of expelling heated air from inside the computer case to the outside. 
         [0019]    A further object of the present invention is to provide a computer cooling apparatus with improved configurations of a heat pipe and a heatsink formed above a CPU to smoothly transfer air to all the heatsinks using one fan. 
         [0020]    A still further object of the present invention to provide a computer cooling apparatus increasing a condensation region of a heat pipe to improve cooling performance of a CPU. 
         [0021]    An even further object of the present invention is to provide a computer cooling apparatus that does not use a separate system fan for the CPU to lower the height of the cooling apparatus and slim the body of the computer case. 
         [0022]    Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
         [0023]    To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a computer cooling apparatus including: a case with an air outlet formed in one side; a fan formed at another side of the case for suctioning external air; a CPU (central processing unit) installed in the case; and a heat radiating device for radiating heat generated from the CPU, wherein the fan and the air outlet are formed in mutually opposite positions, for directing a flow of the external air suctioned by the fan in one direction. 
         [0024]    In another aspect of the present invention, there is provided a computer cooling apparatus including: a case; a CPU (central processing unit) installed in the case; a heat radiating device including a plurality of heat pipes of which at least a portion contacts the CPU, and a heatsink through which at least a portion of the heat pipes passes, for receiving heat transferred from the heat pipes; and a fan formed at one side of the case for suctioning external air. 
         [0025]    In a further aspect of the present invention, there is provided a computer cooling apparatus including: a case; a CPU (central processing unit) installed in the case; a plurality of heat pipes, of which at least a portion directly or indirectly contacts the CPU; a plurality of heatsinks, of which at least a portion contacts the heat pipes to receive heat transferred from the heat pipes, and having at least a portion that is cut away or recessed for admitting air from a sides of the heatsinks; and a fan formed at one side of the case, for allowing external air to flow between the heatsinks. 
         [0026]    In a computer cooling apparatus according to the present invention, the inside of a computer case and the CPU are simultaneously cooled using one fan to improve cooling performance. 
         [0027]    Also, production cost is reduced using only one fan. 
         [0028]    Air inside the computer case flows in one direction using the one fan to smoothly expel the internal heated air to the outside. 
         [0029]    Configurations of a heat pipe and a heatsink formed above the CPU are improved to smoothly transfer air to entire heatsinks using one fan, and a condensation region of the heat pipe is increased to improve cooling performance of the CPU. 
         [0030]    An auxiliary fan separately used for a CPU is not used so that the height of the cooling apparatus is lowered the body of the computer case is slimmed. 
         [0031]    It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
           [0033]      FIG. 1  is a schematic perspective view illustrating a computer cooling apparatus according to the related art; 
           [0034]      FIG. 2  is a schematic perspective view illustrating a computer cooling apparatus according to the present invention; 
           [0035]      FIG. 3  is a plan view illustrating a flow of air suctioned by a fan in a computer body according to the present invention; 
           [0036]      FIG. 4  is a perspective view of a heat-radiating device of a CPU according to a preferred embodiment the present invention; 
           [0037]      FIG. 5  is a left side view of a heat-radiating device according to the present invention; 
           [0038]      FIG. 6  is a right side view of a heat-radiating device according to the present invention; 
           [0039]      FIG. 7  is a front view of a heat-radiating device according to the present invention; 
           [0040]      FIG. 8  is a perspective view illustrating an air flow through a heat-radiating device according to the present invention; 
           [0041]      FIG. 9  is a plan view of a heat-radiating device according to the present invention; 
           [0042]      FIG. 10  is a bottom view of the heat-radiating device according to the present invention; 
           [0043]      FIG. 11  is a schematic perspective view illustrating air flowing around a heatsink according to a first embodiment of the present invention; 
           [0044]      FIG. 12  is a left side view of a heatsink according to a second embodiment of the present invention; 
           [0045]      FIG. 13  is a left side view of a heatsink according to a third embodiment of the present invention; and 
           [0046]      FIG. 14  is a left side view of a heatsink according to a fourth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0047]    Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. 
         [0048]      FIG. 2  is a schematic perspective view illustrating a computer cooling apparatus according to the present invention. 
         [0049]    Referring to  FIG. 2 , the computer cooling apparatus according to the present invention includes a case  100  connected to each of computer components, a mainboard  110  placed in the case  100 , a heat-radiating device  200  for radiating heat generated from a CPU  120 , and fan  130  formed on one side of the case  100 . 
         [0050]    In addition, the heat-radiating device  200  includes a plate  210  mounted on the CPU  120 , a plurality of heat pipes  230  connected to an upper side of the plate  210 , and a plurality of heatsinks  250  connected to the heat pipes  230 . In such a combination as described above, the heat generated form the CPU  120  is transferred to the plate  210  and then to the heat pipes  230 . The heat transferred to the heat pipes  230  is transferred to the heatsinks  250 . The heat transferred to the heatsinks  250  is radiated to the outside air by means of the fan  130 . 
         [0051]    Air outside the case  100  flows into the case  100  by the fan  130 . The suctioned air passes through the heat-radiating device  200 . That is, the air outside the case  100  flows into the case  100  to cool other heat-generating components including the CPU  120 . 
         [0052]    The heatsinks  250  are disposed parallel to a flow direction of the air generated by the fan  130  so as to not interrupt the flow of the air suctioned by the fan  130 . The heatsinks  250  are arranged with a predetermined distance therebetween. The external air flows through spaces between each of the heatsinks  250 . 
         [0053]    The external air suctioned by the fan  130  flows between the plurality of heatsinks  250  to cool the heatsinks  250  and the heat pipes  230 . The air flowing between the heatsinks  250  flows in a forward direction to cool the other heat-generating components such as a chip set and then is radiated to the outside. 
         [0054]      FIG. 3  is a plan view illustrating a flow of air suctioned by a fan in a computer body according to the present invention. 
         [0055]    Referring to  FIG. 3 , arrows indicate air flow. Air suctioned from the outside using the fan flows through spaces between a plurality of heatsinks  250  to cool heat pipes  230  and heatsinks  250  which are formed at an upper portion of the heat-radiating device  200 . The air passing between the plurality of heatsinks  250  flows in a forward direction to cool the entire inside of the computer case  100 . 
         [0056]    That is, the air cooling the heat pipes  230  and the heatsinks  250  flows in the one direction to cool other chip sets coupled to a computer system board. The air heated by flowing along the inside of the computer case  100  flows in the forward direction to be smoothly discharged to the outside without remaining inside the computer. Preferably, an air vent is formed at an end of the air flow path to rapidly exhaust the air heated by heat-exchange into the outside. 
         [0057]      FIG. 4  is a perspective view of a heat-radiating device of a CPU according to a preferred embodiment the present invention. 
         [0058]    Arrows illustrated in  FIG. 4  indicate a flow direction of air suctioned from an outside to an inside of a computer using a fan  130 . 
         [0059]    Referring to  FIG. 4 , the heat-radiating device  120  of the CPU according to the present invention includes a plate  210  mounted on the CPU  120  to receive heat generated from the CPU  120 , a plate fixing unit  220  for fixing the plate  210 , a plurality of heat pipes  230  connected to the plate  210  to receive heat transferred from the plate  210 , a plurality of heatsinks  250  connected to the heat pipes  230  to receive heat transferred from the heat pipes  230 , and a heat pipe fixing unit  270  for fixing the heat pipes  230 . 
         [0060]    In detail, it is preferable that the plate  210  is made of a metal material with high thermal conductivity so that the heat generated from the CPU  120  is rapidly transferred, and at the same time, the heat received from the CPU  120  is rapidly transferred to the heat pipes  250 . 
         [0061]    The heat pipes  230  are closed cylindrical pipes in which liquid refrigerant is charged. The closed cylindrical pipes are curved in a “⊃”-shape. The refrigerant injected inside the heat pipes  230  gathers in a lower horizontal portion of the heat pipes  230  because of gravity. Lower portions of the heat pipes  230  are connected to the plate  210  and upper portions of the heat pipes  230  are connected to the heatsinks  250 . 
         [0062]    Thus, the lower portions of the heat pipes  230  are received from the plate  210  and the upper portions of the heat pipes  230  are received from the heatsinks  250 . That is, the heat pipes  230  transfer the heat generated from the CPU  120  to the heatsinks  250 . 
         [0063]    Although five heat pipes  231 ,  232 ,  233 ,  234 , and  235  are installed in the embodiments, the present invention is not limited thereto. Therefore, an appropriate number of heat pipes may be installed according to the amount of heat generated form the CPU  120 . 
         [0064]    The heatsinks  250  are made of metal plates with a predetermined thickness and thermal conductivity. Preferably, the heatsinks  250  are disposed paralled to a flow direction of air generated by the fan  130  so as to not interrupt a flow of air suctioned by the fan  130 . 
         [0065]    Hereinafter, the cooling of the CPU  120  will be described in detail. 
         [0066]    The heat generated from the CPU  120  is transferred to the plate  210  and the heat received into the plate is transferred to the lower portions of the heat pipes  230 . The refrigerant stored in the lower portions of the heat pipes  230  by the gravity is evaporated by absorbing the heat transferred from the plate  210 . The evaporated refrigerant rises to the upper portions of the heat pipes  230 . The refrigerant moving to the upper portions of the heat pipes  230  is heat exchanged with the air suctioned by the fan  130  to condense the vapor into liquid refrigerant. That is, the refrigerant and the air are heat exchanged by thermal conduction through surfaces of the heat pipes  230 . The liquified refrigerant again descends into the lower portions of the heat pipes  230  through gravity. Therefore, an evaporation process and a liquefaction process of the refrigerant injected into the heat pipes  230  are repeatedly performed to perform heat exchange. This heat exchange method has a higher heat transfer rate than that of only a metal material. 
         [0067]    The heatsinks  250  are made of metal plates with a wide surface. Therefore, the heat transferred from the upper portions of the heat pipes  230  is rapidly radiated into the external air suctioned by the fan  130 . 
         [0068]    The air suctioned by the fan  130  flows between the heatsinks  250 . Thus, the air is directly heat exchanged with the heat pipes  230 , and at the same time, indirectly heat exchanged by the heatsinks  250 . Therefore, cooling performance of the CPU  120  is improved. 
         [0069]      FIG. 5  is a left side view of a heat-radiating device according to the present invention,  FIG. 6  is a right side view of the heat-radiating device,  FIG. 7  is a front view of the heat-radiating device, and  FIG. 8  is a perspective view illustrating air flow through the heat-radiating device. 
         [0070]    Arrows illustrated in  FIG. 5 ,  FIG. 6 , and  FIG. 7  indicate a flow direction of air suctioned from an outside to an inside of a computer using a fan  130 . 
         [0071]    Hereinafter, configurations of a plate  210 , heat pipes  230 , and heatsinks  250  and heat exchange processes therein will be described in detail with reference to  FIG. 5  through  FIG. 8 . 
         [0072]    Referring to  FIG. 5  through  FIG. 8 , the plate  210  has a block shape with a predetermined thickness. A space is formed between a lower surface  211  and an upper surface  212 . The lower surface  211  of the plate  210  contacts an upper surface of a CPU  120 . Grooves (refer to  FIG. 5 ) are formed on a left side surface of the plate  210 . Lower portions of the heat pipes  230  are fixedly fitted in the grooves. A plurality of holes are defined in the right side surface of the plate  210 . The lower portions of the heat pipes  230  pass through the holes. That is, the grooves and the holes corresponding to the number of the heat pipes  230  are formed on the left and right side surfaces of the plate  210 , respectively. The lower portions of the plurality of the heat pipes  230  contact the lower surface of the plate  211 . 
         [0073]    The lower portions of the heat pipes  230  receive heat from a lower portion of the plate  210  in a state in which the lower portions are fixed by the grooves and the holes defined in the left/right side surfaces of the plate  210 . 
         [0074]    A plurality of through holes are defined in the heatsinks  250  so that the upper portions of the heat pipes  230  having a “⊃”-shape pass through the holes. In the embodiments, five through holes  251 ,  252 ,  253 ,  254 , and  255  are defined in one heatsink  250  so that five heat pipes  230  pass through the holes, respectively. 
         [0075]    That is, upper portions of a first heat pipe  231 , a second heat pipe  232 , a third heat pipe  233 , a fourth heat pipe  234 , and a fifth heat pipe  255  pass through a first through hole  251 , a second through hole  252 , a third through hole  253 , a fourth through hole  254 , and a fifth through hole  255 , respectively. 
         [0076]    The upper portions of the heat pipes  230  are longer than the lower portions thereof. By such a construction of the heat pipes  230 , the lower portions of the heat pipes  230  that concentrically receive the heat from the plate  210  and the upper portions of the heat pipes  230  have a wider air contacting surface. Refrigerant stagnant at the upper portions of the heat pipes  230  is easily evaporated by the heat transferred from the plate  210 . The evaporated refrigerant is rapidly concentrated by thermal conduction in the upper portions of the heat pipes  230  having a relatively wide surface. As a result, the heat transfer rate of the heat pipes  230  is improved, thereby improving the overall cooling performance of the heat-radiating device  200 . 
         [0077]    Meanwhile, the first and fifth through holes  251  and  255  are disposed under the second, third, and fourth through holes  252 ,  253 , and  254 . Spaces of the second, third, and fourth through holes  252 ,  253 , and  254  are wider than that of the through holes defined in the right side surface of the plate  210 . That is, the heat pipes fan out in an upward direction as illustrated in  FIG. 6 . 
         [0078]    Referring to  FIG. 7 , air suctioned from the outside of computer to the front of the heat-radiating device  200  cools the first and second heat pipes  231  and  232  at the same time. The flowing air can easily flow between each of heat pipes because spaces between the first through fifth heat pipes  231 ,  232 ,  233 ,  234 , and  235  are wide. 
         [0079]    A point of the lower portions in the heatsinks  250  is sunken upwardly to a predetermined depth. The height of the front portion of the heatsinks  250  is longer than that of the rear portion. 
         [0080]    In detail, lower sides of portions in which the third heat pipe passes through the heatsinks  250  are depressed upward. A lower side of portions in which the fourth and fifth heat pipes  234  and  235  pass through the heatsinks  250  is short so that the lower side is separated from the plate  210  with a predetermined space. Meanwhile, a lower side of portions in which the first and second heat pipes  231  and  232  pass through the heatsinks  250  is long so that the lower side is connected to the plate  210 . 
         [0081]    In a configuration of the above-described heatsinks  250 , an air flow path having a triangular shape is formed under a central portion of the heatsinks  250  and also an air flow path is formed under the rear portion of the heatsinks  250 . 
         [0082]    Referring to  FIG. 8 , the air suctioned into the heat-radiating device  200  flows in a rear direction of the heat-radiating device  200  and absorbs heat. Air heated by the heat exchange forms an ascending air current and flows toward the upper portions of the third, fourth, and fifth heat pipes  233 ,  234 , and  235 . Thus, the third, fourth, and fifth heat pipes  233 ,  234 , and  235  are also effectively cooled by a flow of the air suctioned by the fan  130 . Therefore, a condensation region of the heat pipes  250  increases to improve a cooling effect. 
         [0083]    Air flow passing between the heatsinks  250  will be described in detail with reference to the accompanying drawings. 
         [0000]    
       
         
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                 Heatsink according to 
               
               
                   
                 Related Art 
                 preferred embodiment of 
               
               
                   
                 Heatsink 
                 present invention 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Thermal resistance 
                 0.304° C./W 
                 0.230° C./W 
               
               
                   
                   
               
             
          
         
       
     
         [0084]    According to Table 1, the cooling effect of the CPU due to the heatsink according to the present invention is readily apparent. 
         [0085]    In the experiment of Table 1, the heatsink according to the related art has an identical rectangular shape in which a length of a front portion is equal to a length of a rear portion. Thus, the lower portion of the heatsink contacts the plate  210 . The experiment is performed at an ambient temperature of 25° C. Also, the experiment is performed under the same conditions except for a different shape of the heatsink. 
         [0086]    The thermal resistance of the Table 1 is a property which interferes with thermal conduction. When the thermal resistance value is low, the temperature rising rate is low. 
         [0087]    As a result of the Table 1, a temperature of the CPU using the heatsink  250  according to the present invention is lower than that of the related art heatsink. For example, if the calorific value of the CPU is 100 W, the temperature of the CPU using the heatsink according to the present invention is 25° C., but the temperature of the CPU using the conventional heatsink is 30.4° C. That is, the temperature of the CPU using the heatsink according to the present invention is low by 6.6° C. compared to the temperature of the CPU using the conventional heatsink. A heatsink effect increases by using the heatsink according to the present invention. As the calorific value of the CPU increases, this temperature difference is much larger. For example, if the calorific value of the CPU is 200 W, the temperature of the CPU using the heatsink  250  according to the present invention is low by 13.2° C. compared to the temperature of the CPU using the conventional heatsink. 
         [0088]    Therefore, the cooling performance of the CPU increases by using the heatsink according to the present invention. Although the heatsink  250  in the heat-radiating device according to the present invention is described as a preferred embodiment, the present invention is not limited thereto. Therefore, different heatsinks except for the heatsink  250  may also be described as an embodiment of the present invention. 
         [0089]      FIG. 9  is a plan view of a heat-radiating device according to the present invention and  FIG. 10  is a bottom view of the heat-radiating device according to the present invention. 
         [0090]    Hereinafter, a plate  210 , a plate fixing unit  220 , and a heat pipe fixing unit  270  will be described in detail with reference to  FIG. 9  and  FIG. 10 . 
         [0091]    Hereinafter, configurations of a plate  210 , heat pipes  230 , and heatsinks  250  and a heat exchange process therein will be described in detail with reference to  FIG. 9  through  FIG. 10 . 
         [0092]    Referring to  FIG. 9  and  FIG. 10 , an entire bottom surface  211  of the plate  210  contacts an upper surface of a CPU  120 . A hole  213  is defined in a central portion of an upper surface  212  of the plate  210 . 
         [0093]    Heat generated from the CPU  120  is transferred to the bottom surface  211  of the plate  210 . A part of the heat transferred to the bottom surface  211  is transferred to upper portions of the heat pipes  230  and the heatsinks  250  through lower portions of the heat pipes  230 . A part of the rest of the heat transferred to the bottom surface  211  is directly transferred to external air through the hole  213 . 
         [0094]    The plate fixing unit  220  includes first through fourth plate fixing units  221 ,  222 ,  223 , and  224 , which are formed with a step height corresponding to the thickness of the plate  210 . 
         [0095]    Each of upper portions of the first through fourth plate fixing units  221 ,  222 ,  223 , and  224  is screwed respectively at four apexes of the upper surface  212  of the plate  210 . Lower portions of the first through fourth plate fixing units  221 ,  222 ,  223 , and  224  are screwed to a bottom surface of a case  100 . Therefore, the plate fixing unit  220  firmly fixes the plate  210  to the case  100 . 
         [0096]    Two protrusions  271  are protrusively formed at both sides of an upper portion of the heat pipe fixing unit  271  and two ribs  272  are protrusively formed at both sides of a lower portion (refer to  FIG. 8 ). 
         [0097]    In detail, a circular groove is formed on the protrusion  271 . An upper portion of a second heat pipe  232  is inserted in the groove. The second heat pipe  232  is fixed by the heat pipe fixing unit  270 . A heatsink in which the second heat pipe  232  passes therethrough is fixed at the second heat pipe  232 . Thus, the remainding first, third, fourth, and fifth heat pipes  231 ,  233 ,  234 , and  235  passing through each of heatsinks  250  are also fixed. 
         [0098]    A hole is defined in the rib  272  and a coupling member such as a screw passes through the hole and holes defined in the lower portion of the first and second plate fixing units  221  and  222  to couple to the bottom surface of the case  100 . Accordingly, the heat pipe fixing unit  220  is fixed to the bottom surface of the case  100  together with the first and second plate fixing units  221  and  222 . Accordingly, fabrication is easy and cost of manufacture is reduced compared to a fabricating method according to the related art in which the heat pipe fixing unit  270  and the plate fixing units  221  and  222  are separately fixed. 
         [0099]    In Table 1 below, effects of a heat-radiating device according to the related art and the heat-radiating device according to the present invention are more clearly compared. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                   
                   
                 CPU 
                 CPU 
               
               
                   
                 Heat pipe 
                 Fan 
                 power 
                 Tcase 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Conventional 
                 6Φ(five units) 
                 92 × 92 × 25 
                 115 W 
                 104.63° C. 
               
               
                 Heat-radiating 
               
               
                 Device 
               
               
                 Heat-radiating 
                 6Φ(five units) 
                 80 × 80 × 20 
                 115 W 
                  66.82° C. 
               
               
                 Device According 
               
               
                 to Present 
               
               
                 Invention 
               
               
                   
               
             
          
         
       
     
         [0100]    In the experiment of Table 2, the heat pipes have an identical size, and an identical number of the heat pipes are used. Also, the calorific value of the CPUs is identical. However, the capacity of a fan that is used in the heat-radiating device according to the related art is much larger than that of the fan that is used in the heat-radiating device according to the present invention. 
         [0101]    As shown in Table 2, although a fan having low capacity in comparison with the fan according to the related art is used, a CPU surface temperature of the heat-radiating device according to the present invention is much lower than that of the related art heat-radiating device. The heat-radiating device according to the present invention is superior to the heat-radiating device according to the related art. 
         [0102]      FIG. 11  is a schematic perspective view illustrating air flowing around a heatsink according to a first embodiment of the present invention. 
         [0103]    Referring to  FIG. 11 , a plurality of through holes  251 ,  252 ,  253 ,  254 , and  255  are defined at predetermined points in a heatsink  250  according to the present invention. A recess  256  depressed in an upper direction is formed at a lower portion of the heatsink  250 . 
         [0104]    In the heatsink, an vertical length of a front portion is longer than that of a rear portion. The recess  256  is formed by a front inclined plane  258 , which is inclined from a front lower portion rearward with a predetermined angle and a rear inclined plane  257 , which is inclined from a rear lower portion frontward with a predetermined angle. 
         [0105]    External air suctioned from a front of the heat-radiating device  200  absorbs heat transferred from the CPU to increase in temperature. As described above, an ascending air current is formed in the rear of the heatsink  250  because the air becomes lighter as the temperature increases. Preferably, the rear inclined plane  257  is inclined to intersect with the ascending air current, thereby increasing a heat exchanging area. 
         [0106]    Pressure in a lower space of the heatsink  250  is less than that of a surrounding space because the external air flows toward the rear of the heatsink  250 , and the heated air ascends. As a result, air having relatively low temperature, which is distributed around the heat-radiating device gathers from a central direction to both sides of the heat-radiating device. The heat generated from the CPU is rapidly radiated to improve cooling efficiency. 
         [0107]    As described in the heatsink according to the present invention, the length of a rear lower portion of the heatsink is shorter than that of the front lower portion of the heatsink so as to not interrupt a flow of air suctioned from both sides. 
         [0108]      FIG. 12  is a left side view of a heatsink according to a second embodiment of the present invention. 
         [0109]    Referring to  FIG. 12 , the heatsink  350  according to the second embodiment of the present invention is bent a plurality of times. 
         [0110]    A plurality of through holes  351 ,  352 ,  353 ,  354 , and  355  for passing a heat pipe through as in the first embodiment are defined in the heatsink  350 . The heatsink  350  includes a major portion  356  of a predetermined length extending in a front to rear direction and a minor portion  357  extending in a front to rear direction under the major portion  356 . The minor portion  357  is shorter than the major portion  356 . A recess  358  is formed between the major portion  356  and the minor portion  357 . 
         [0111]    External air suctioned from the front of the heatsink  350  moves to the rear of the heatsink  350  and absorbs heat. Therefore, the heated air ascends. Also, the heated air is suctioned from both sides of the heatsink  350  through a recess  358 . That is, the recess  358  is a path that can smoothly suction air from both sides of the heatsink  350 . 
         [0112]    A front-to-rear length (c) of the major portion  356  is longer than a front-to-rear length (d) of the minor portion  357 , thereby increasing a contact area between the air ascending by evaporation and the heatsink  350 . 
         [0113]    A vertical length (a) of the major portion  356  is longer than a vertical length (b) of the minor portion  357 , thereby increasing the contact area between the air and the heatsink  350 . 
         [0114]      FIG. 13  is a left side view of a heatsink according to a third embodiment of the present invention. 
         [0115]    Referring to  FIG. 13 , the heatsink  450  according to the third embodiment of the present invention has an “L”-shape. 
         [0116]    A plurality of through holes  451 ,  452 ,  453 ,  454 , and  455  for passing a heat pipe through are defined in the heatsink  450 . A part of a lower portion of the heatsink  450  is sectioned to easily suction air from both sides of the heatsink  450 . 
         [0117]    An area of the sectioned region becomes larger to minimize flow resistance of air suctioned from both sides of the heatsink  450 . 
         [0118]      FIG. 14  is a left side view of a heatsink according to a fourth embodiment of the present invention. 
         [0119]    Referring to  FIG. 14 , the heatsink  550  according to the fourth embodiment of the present invention has a “U”-shape bent toward the right. 
         [0120]    The heatsink  550  includes an upper section  556  and a lower section  557 . The upper section  556  extends in a front-to-rear direction by a predetermined length. The lower section  557  is separated from the upper section  556  to a lower portion and extends in the front-to-rear direction. A plurality of through holes  551 ,  552 ,  554 , and  555  for passing a heat pipe through are defined in the heatsink  550 , as in the first through third embodiments. A length of the lower section  557  is equal to a length of the upper section  556 . Also, a width of the upper section  556  is larger than that of the lower section  557 , thereby increasing a heat exchange area between the suctioned air and the heatsink  550 . The lower section  557  and the upper section  556  extend by an equal length, thereby increasing heat transfer from a plate  220 . 
         [0121]    A recess  558  is formed between the upper section  556  and the lower section  557  to smoothly suction external air from both sides of the heatsink  550 . The reason that air is suctioned from both sides of the heatsink  550  is omitted because it is described above. 
         [0122]    The invention may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.