Patent Publication Number: US-2011056670-A1

Title: Heat sink

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a heat sink, and in particular to a heat sink for dissipating the heat generated by various electronic products. 
     2. Description of Prior Art 
     With the advancement of modern computer information, the working speed of electronic products such as CPU, IC element, power chip, power supply or the like increases so fast that they will generate a large amount of heat in high-speed operation. If the heat is not dissipated timely, the normal operation of the electronic products will be affected, which may reduce the operating performance, cause the hardware to suffer damage, and shorten their lifetime. In order to solve the problem that the electronic elements may be overheated, a common solution is to mount aluminum-extruded heat-dissipating fins on a heat-generating source. The heat-dissipating fins conduct the heat to the outside, and a fan is used to generate compulsory convection of air to increase the heat conduction. Thus, the heat-dissipating effect can be achieved, and the normal working temperature of the electronic device can be maintained. 
     The heat-dissipating fins are commonly made by extruding aluminum materials. However, due to the limitation in the technology of molds and the pressing process, the thus-made fins are arranged densely in one direction with identical intervals. Thus, the airflow is divided by each fin and can be flown between the respective fins. The wide-and-thick fins enlarge the surface area blocking airflow, as a result of which the air having absorbed heat may not be exhausted rapidly. Thus, a great amount of hot air is still accumulated in the lower portion of the fins, so that the hot air cannot be heat-exchanged with the cooler air on the upper portion of the fins. Therefore, the heat-conducting speed is so slow as to affect the heat-dissipating effect. 
     Therefore, in order to overcome the above problems, the present Inventor proposes a reasonable and novel structure based on his delicate researches and expert experiments. 
     SUMMARY OF THE INVENTION 
     The present invention is to provide a heat sink, in which airflow can flow freely among the respective heat-dissipating fins. The small pitch region formed in the respective heat-dissipating fins is used to dissipate a great amount of heat, while the large pitch region formed in the respective heat-dissipating fins is used to exhaust the air rapidly. 
     The present invention is to provide a heat sink, which includes a frame; a vapor chamber fixed to the frame; and a heat-dissipating plate adhered to one surface of the vapor chamber. The heat-dissipating plate has a first heat-dissipating fins region and a second heat-dissipating fins region. The first heat-dissipating fins region and the second heat-dissipating fins region are constituted of a plurality of first heat-dissipating fins and a plurality of second heat-dissipating fins that are arranged at intervals. The pitch of the first heat-dissipating fins in the first heat-dissipating fins region is smaller than that of the second heat-dissipating fins in the second heat-dissipating fins region. 
     The present invention has advantageous effects as follows. The first heat-dissipating fins region has a plurality of first heat-dissipating fins that are distributed densely, while the second heat-dissipating fins region has a plurality of second heat-dissipating fins that are distributed sparsely. The outside of the first heat-dissipating fins region is connected to a fan. The first heat-dissipating fins region is used as an intake end, while the second heat-dissipating fins region is used as an exhaust end. The first heat-dissipating fins region having a small pitch of the respective first heat-dissipating fins forms a large contact area for air, so that the air can absorb the heat enough to conduct a large amount of heat to the outside. The second heat-dissipating fins region having a large pitch of the respective second heat-dissipating fins forms large air passages for exhausting hot air rapidly. By this arrangement, the heat-dissipating plate has a plurality of heat-dissipating fins with different densities, whereby the heat-dissipating efficiency can be increased. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of the present invention; 
         FIG. 2  is an assembled perspective view of the present invention; 
         FIG. 3  is a top view of the present invention; 
         FIG. 4  is a schematic view showing that the fan enhances the airflow according to the present invention; and 
         FIG. 5  is a schematic view showing an integrally-formed heat-dissipating plate according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The characteristics and technical contents of the present invention will be explained in more detail with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit the present invention. 
     Please refer to  FIGS. 1 to 3 . The present invention provides a heat sink, which includes a frame  10 , a vapor chamber  20  and a heat-dissipating plate  30 . 
     The frame  10  comprises a rim  11  and an elongate plate  12  extending from the outer edge of the rim  11 . The rim  11  is provided with a hollow portion  111  and a first through-hole  112 . The bottom edge of the rim  11  extends inward to form a plurality of supporting plates  113 . The elongate plate  12  is provided with a second through-hole  121 . 
     The vapor chamber  20  comprises an upper surface  21  and a lower surface  22  formed on the other side of the upper surface  21 . The vapor chamber  20  is embedded into the hollow portion  111  with its lower surface  22  being adhered to each supporting plate  113 . The inner walls of the vapor chamber  20  form a sealed thin casing in which a capillary structure is distributed. The interior of the vapor chamber  20  forms a vacuum accommodating space in which a working fluid is filled. When the lower surface  22  is brought into contact with a heat-generating element to raise its temperature, the working fluid in the accommodating space absorbs sufficient heat to induce a phase change from liquid state to vapor state. The high-temperature vapor flows to the low-temperature upper portion of the casing to release heat. Then, the heat is conducted to the heat-dissipating piece. Thereafter, the vapor is subjected to a phase change to liquid state and then flows to the lower portion of the casing. By the continuous circulation of the working fluid, the waste heat generated by the heat-generating element can be taken away. 
     The heat-dissipating plate  30  is made of metals having good heat conductivity such as aluminum or copper. The heat-dissipating plate  30  comprises a first heat-dissipating fins region  31  and a second heat-dissipating fins region  32  adjacent to the first heat-dissipating fins region  31 . The first heat-dissipating fins region  31  and the second heat-dissipating fins region  32  are formed separately. By a press-forming process, the first heat-dissipating fins region  31  is formed with a plurality of first heat-dissipating fins  314  that protrude upwards and are arranged at intervals. By a press-forming process, the second heat-dissipating fins region  32  is formed with a plurality of second heat-dissipating fins  321  that protrude upwards and are arranged at intervals. The first heat-dissipating fins region  31  and the second heat-dissipating fins region  32  are located on the same one heat-dissipating passage. 
     The pitch and height of the respective first heat-dissipating fins  314  of the first heat-dissipating fins region  31  are smaller than those of the second heat-dissipating fins  321  of the second heat-dissipating fins region  32 . Furthermore, the heights of the respective first heat-dissipating fins  312  and the heights of the respective second heat-dissipating fins  321  decrease gradually from the front side of the heat-dissipating plate  30  towards its rear side. The gradual decrease in height can cooperate with the elements other than the heat-dissipating device in terms of space. 
     The first heat-dissipating fins region  31  comprises  1  main body  311  and a rear fin  312  extending from an outer edge of the main body  311 . The main body  311  is provided with an opening  313  for cooperating with the elements other than the heat-dissipating device in terms of space. The heat-dissipating plate  30  further comprises a third heat-dissipating fins region  33 . The second heat-dissipating fins region  32  and the main body  311  are adhered to the upper surface of the vapor chamber  20  and the rim  11 . The third heat-dissipating fins region  33  and the rear fin  312  are adhered to the elongate plate  12 . The second through-hole  121  is located between the third heat-dissipating fins region  33  and the rear fin  312 . 
     Two screws  40  penetrate the first through-hole  112  and the second through-hole  121  respectively. In this way, the heat-dissipating device can be fixed to a base for the element other than the heat-dissipating device to form a firm assembly. 
     Please refer to  FIG. 4 . Both the frame  10  and the vapor chamber  20  are heat conductors having good heat conductivity. The rim  10  and the vapor chamber  20  of the heat-dissipating device are adhered to a heat-generating source  60 , thereby conducting the heat to the heat-dissipating plate  30 . The outside of the first heat-dissipating fins region  31  away from the second heat-dissipating fins region  32  is provided with a fan  50  to blow the airflow from the first heat-dissipating fins region  31  to the second heat-dissipating fins region  32 . The first heat-dissipating fins region  31  is used an intake end, while the second heat-dissipating fins region  32  is used to an exhaust end. The first heat-dissipating fins region  31  having a smaller pitch of the respective first heat-dissipating fins  314  forms a large contact area for air, so that the air can absorb the heat sufficiently to thereby conduct a great amount of heat of the heat source to the outside. The second heat-dissipating fins region  32  having a larger pitch of the respective second heat-dissipating fins  321  forms large air passages, so that the air can be exhausted rapidly to achieve a good exhausting efficiency. 
     Please refer to  FIG. 5 . The first heat-dissipating fins region  31  and the second heat-dissipating fins region  32  of the heat-dissipating plate  30  can be formed integrally, and then both of them are pressed to form the first heat-dissipating fins  314  and the second heat-dissipating fins  321  with different heights and pitches. 
     Although the present invention has been described with reference to the foregoing preferred embodiment, it will be understood that the invention is not limited to the details thereof. Various equivalent variations and modifications can still occur to those skilled in this art in view of the teachings of the present invention. Thus, all such variations and equivalent modifications are also embraced within the scope of the invention as defined in the appended claims.