Abstract:
A heat dissipation apparatus used in a computer comprises a heat sink and a star-shaped spring with multiple directional arms, wherein each directional arm extends in a corresponding direction, and the tangent direction of the corresponding contact boundary formed by securing the direction arm to the heat sink is perpendicular to the corresponding direction. The force imposed from the spring on the heat sink is uniform as a result of the perpendicular mechanism.

Description:
RELATED APPLICATIONS 
   The present application is based on, and claims priority from, Taiwan Application Serial Number 95202468, filed Feb. 13, 2006, the disclosure of which is hereby incorporated by reference herein in its entirety. 
   BACKGROUND 
   1. Field of Invention 
   The present invention relates to a heat dissipation apparatus. More particularly, the present invention relates to a heat dissipation capable of averaging the imposed force on the heat sink. 
   2. Description of Related Art 
   To meet the demands of modern life, and progress in technology, electronic devices are increasingly able to provide more functions and services. For example, portable notebooks are a popular and successful product and not only because of the reasons stated above, but also because they are light and small in size. 
   Most notebooks have a heat dissipation apparatus to lower the high temperatures generated by working electronic elements. If the temperatures are not lowered adequately, once the temperature is higher than the critical temperature, the electronic components would get damaged. 
   A heat dissipation apparatus usually comprises of a heat sink and a spring. Heat dissipation efficiency (heat conduction) depends on the compactness of the contact area between the heat sink and the electronic component. If the compactness of the contact area between the heat sink and the electronic component is high (it is good for heat conduction), the heat dissipation efficiency is high; and if the compactness of the contact area between the heat sink and the electronic component is low, the heat dissipation efficiency is low. 
   Heat sinks usually have deformed shapes instead of rectangular shapes in order to meet the space limitations and element placement in an electronic device such as a notebook. The ability of a spring to apply a uniform force to a heat sink with a deformed shape is lower than the ability of the spring to apply a uniform force to a heat sink with a regular shape. Therefore, if a spring is used to apply a force to a heat sink with a deformed shape, the compactness of the contact plane between the heat sink and the electronic component is low and is therefore not effective for lowering the temperature (the higher the compactness the better heat efficiency). 
     FIG. 1  shows a schematic diagram for one kind of conventional heat dissipation apparatus  100 . The heat dissipation apparatus  100  used to expel hot air generated by an electronic component (not shown) includes a heat sink  21  and a spring  10 . The spring  10  that is used to secure the heat sink  21  to an electronic component (not shown) usually has an angular shape. The angular shaped spring  10  secures the heat sink  21  to the electronic component (not shown) and prevents the heat sink  21  from breaking away from the electronic component (not shown) and effectively prevents a reduction in the heat dissipation efficiency of the heat sink  21 . 
   SUMMARY 
   It is therefore an aspect of the present invention to provide a heat dissipation apparatus to enhance the heat dissipation efficiency. 
   The heat dissipation apparatus comprises a heat sink and an angular shaped spring with multiple directional arms, wherein each of the directional arms extends in a corresponding direction to secure the heat sink, and the tangent directions of the contact boundary between the heat sink and the multi directional arms on the spring are perpendicular to the directions of the arm extensions. If the above tangents are indeed perpendicular to the direction of the spring arms, the force imposed from the spring on the heat sink would be uniform throughout the heat sink and the compactness of the contact area between the heat sink and the electronic component would be higher and the heat dissipation efficiency would increase hence lowering the risk of a system crash or damage due to overheating. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims and accompanying drawings where: 
       FIG. 1  is a schematic diagram of a conventional heat dissipation apparatus; 
       FIG. 2  is a schematic diagram of a heat dissipation apparatus in accordance with a preferred embodiment of the present invention; 
       FIG. 3  is a schematic diagram of a heat dissipation apparatus in accordance with another preferred embodiment of the present invention; 
       FIG. 4  is a force simulation diagram of a conventional heat dissipation apparatus; and 
       FIG. 5  is a force simulation diagram of a heat dissipation apparatus in accordance with a preferred embodiment of the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 2  is a schematic diagram of a heat dissipation apparatus in accordance with a preferred embodiment of the present invention. In  FIG. 2 , star-shaped spring  10  has three directional arms  11 ,  12  and  13  that respectively extend in three corresponding directions  111 ,  121  and  131  and are directly secured on the heat sink  21  to form three pieces of contact boundaries. Tangent directions  122  and  132  of the contact boundary between the heat sink  21  and the directional arms  12  and  13  of the star-shaped spring  10  are perpendicular to the corresponding directions  121  and  131 , respectively. In the embodiment, the tangent direction  112  is originally perpendicular to the corresponding direction  111 . The difference between  FIG. 1  and  FIG. 2  is that all the tangent directions  112 ,  122  and  132  in  FIG. 2  are perpendicular to the corresponding directions  111 ,  121  and  131  respectively, whereas apart from the tangent direction for directional arm  11 , the remaining tangent directions in  FIG. 1  are not perpendicular to the directional arms  12  and  13 . The advantage is that, with the perpendicular mechanism ( FIG. 2 ), the ability of the star-shaped spring  10  to exert a uniform force on the heat sink is higher than if the tangents to the directional arms are not perpendicular ( FIG. 1 ). 
     FIG. 3  is a schematic diagram of a heat dissipation apparatus in accordance with another preferred embodiment of the present invention. The distinction between the two embodiments ( FIG. 2  and  FIG. 3 ) is the perpendicular mechanism between the tangent directions  112 ,  122  and  132  and the corresponding directions  111 ,  121  and  131 . In  FIG. 2 , the corners on the lower right and lower left sides of the heat sink are “cut” to form the tangent directions  122  and  132  which are perpendicular to the corresponding directions  121  and  131  respectively. In  FIG. 3  the corners on the lower right and lower left side of the heat sink are “extended” to form the tangent directions  122  and  132  which are also perpendicular to corresponding directions  121  and  131  respectively. 
   Another advantage in this embodiment ( FIG. 3 ) is that extending the corners of the heat sink  21  is equivalent to shortening the directional arms  12  and  13 , in other words this could increase the magnitude of force imposed by star-shaped spring  10  on the heat sink  21  without any additional placement space. Thus the contact area would be more compact and better heat dissipation efficiency could be achieved. 
   The spirit of the invention is that the corresponding directions of the multi directional arms have to be perpendicular to the tangent directions of the contact boundary between the heat sink and the multi directional arms on the spring. Therefore, the shape of the star-shaped spring  10  does not matter (and is not limited to a tri-star spring with three directional arms  11 ,  12  and  13 ) as long as the heat sink  21  could be fixed firmly. 
     FIG. 4  is a force simulation diagram of a conventional heat dissipation apparatus ( FIG. 1 ). The central area  31  represents the zone of an electronic component  360  (a central processing unit (CPU), a chipset or a graphic processing unit (GPU) for example) on which the force from a heat sink  21  is imposed. The arrow symbols  310 ,  320 ,  330  and  340  represent the magnitude of the imposed force: the longer the arrow the larger the magnitude. From  FIG. 4 , it could be understood that due to space limitations and element placement, the contact boundary between the heat sink  21  and the multi directional arms  11 ,  12  and  13  on the spring could not be designed so the previously mentioned perpendicular mechanism mentioned above and the force imposed would not be uniform on the heat sink  21 , in other words the length of those arrow symbols  310 ,  320   330  and  340  at the four corners of the central area  31  are not the same. 
     FIG. 5  is a force simulation diagram of a heat dissipation apparatus in accordance with a preferred embodiment of the present invention ( FIG. 2 ). The central area  31  represents the zone of an electronic component  360  (a CPU, chipset or GPU for example) on which the force from a heat sink  21  is imposed. The arrow symbols  310 ,  320 ,  330  and  340  represent the magnitude of the imposed force: the longer the length of the arrow the larger of the magnitude. From  FIG. 5 , the lengths of each arrow symbol  310 ,  320 ,  330  and  340  are almost the same because the corresponding directions (refer to  FIG. 3 ) of the directional arms  11 ,  12  and  13  are perpendicular to the tangent direction (refer to  FIG. 3 ) of the contact boundary between the heat sink  21  and the directional arms  11 ,  12  and  13  on the spring. 
   It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.