Abstract:
A radiation structure is employed in electronic apparatus such as a laptop computer having a body containing a heat generating element (e.g. CPU) and a display, rotatably connected to the body. The radiation structure transfers heat from the CPU to the outside of the apparatus and includes a first heatpipe; a hinge member connected to the host heatpipe for receiving heat therefrom; a second heatpipe for transferring heat from the hinge member to a radiation member placed in the display, one end of the second heatpipe being arranged substantially coaxially with the center of rotation of the display; and a sleeve member arranged in the hinge member coaxially with respect to the center of rotation of the display, the sleeve member being inserted from the outside into the inside of the display together with a portion of the second heatpipe which projects from the hinge member.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to electronic equipment such as a notebook-type personal computer or word processor which is configured to have a display part rotationally supported by a body and relates to a radiation structure for radiating heat from a heating element such as a CPU placed in the body to the outside of the equipment as well as to electronic equipment or a computer apparatus which has such a radiation structure. 
     2. Description of the Related Art 
     Recently, as electronic equipment such as a notebook-type personal computer (hereinafter referred to as “notebook computer”) becomes more advanced and faster, various electronic elements represented by a central processing unit (CPU), which may produce heat, tend to produce more and more heat. In particular, since more power consumption of an electronic element for faster operations facilitates a rise in temperature of the electronic element, some protection may be required against such a temperature rise. 
     Insufficient protection against radiation from such electronic equipment may cause the electronic element to have an increased error rate due to such a temperature rise or to be made unstable because of increased actuations of a protective circuit and thus, the service life of the equipment may be reduced due to a thermally degraded electronic element. In order to avoid these problems, various types of electronic equipment employ some radiation structure as a heat protection. 
     FIG. 5 shows a heatpipe hinge radiation mechanism as an example for a conventional radiation structure used for a notebook computer. The notebook computer includes a body  10  and a display part  12  and the display part  12  is rotationally connected to the body  10  through a hinge (not shown) to allow the display part  12  to function as a cover for the body  10  as well. It should be noted that a CPU (not shown) and other components are contained in the body  10 . It should also be noted that the display part  12  has a liquid crystal display part (LCD)  13  and some other components built therein. 
     The conventional heatpipe hinge radiation mechanism  14  shown in FIG. 5 transfers heat produced in the body  10  to the display part  12  to suppress any temperature rise within the body  10  and on its outer surface of the body  10 . The heatpipe hinge radiation mechanism  14  includes a heat sink  16  provided within the body  10 . The heat sink  16  takes the form of thick plate and is supported above a CPU (not shown) mounted on a printed circuit board. The heat sink  16  is in contact with the CPU directly or indirectly through a cushioning material with a high thermal conductivity such as silicone rubber to absorb any heat from the CPU or other electronic components. 
     One end of the heatpipe  18  is connected to the end of the heat sink  16 . The heatpipe hinge radiation mechanism  14  includes a heatpipe hinge  20  for connecting the body  10  and the display part  12 . The heatpipe hinge  20  connects the body  10  to the display part  12  rotationally with respect thereto. However, the body  10  is also connected to the display part  12  by a hinge (not shown) rotationally with respect thereto and any load of the body  10  and the display part  12  is supported by the hinge mechanism to prevent it from directly acting on the heatpipe hinge  20 . 
     The heatpipe hinge  20  includes a fixed plate  22  fixed to a chassis (not shown) within the body  10  and the other end of the heatpipe  18  is connected to the fixed plate  22 . The fixed plate  22  includes a rotationally annular bearing  24  integrally provided along the upper longitudinal edge and one end of another heatpipe  26  is rotationally inserted into the bearing  24 . Therefore, the fixed plate  22  is connected to the heatpipe  26  rotationally with respect thereto around the axis S of the bearing  24 . 
     A portion of the heatpipe  26  which projects from the bearing  24  passes through a cylindrical sleeve  27  and then it is inserted into the display part  12 . It should be noted that the fixed plate  22  and the sleeve  27  are made of a metal material with a high thermal conductivity, respectively. This allows the heatpipe  22  to receive any heat directly from the fixed plate  22  and indirectly from the fixed plate  22  through the sleeve  27 . 
     On the contrary, a thin-plate radiation plate  28  is arranged on the back of the LCD  13  in the display part  12 . The radiation plate  28  is also made of a metal material with a high thermal conductivity and the other end of the heatpipe  26  is connected thereto. 
     In the heatpipe hinge radiation mechanism  14  as configured above, any heat produced by the CPU and other components during the operation of the notebook computer is absorbed by the heat sink  16  and the heat stored in the heat sink  16  is transformed to the radiation plate  28  through the heatpipe  18 , the heatpipe hinge  20 , and the heatpipe  26 . This allows the heat produced in the body  10  to be efficiently transferred to the radiation plate  28  of the display part  12  for heat emission from the radiation plate  28  to the outside of the apparatus and thus, any excessive rise in temperature can be avoided both within the body  10  and on the outer surface of the body  10 . 
     Although the heatpipe hinge radiation mechanism  14  as described above consists of a plurality of parts such as heat sink  16 , the heatpipes  18  and  26 , and the heatpipe hinge  20 , it is supplied in the form of a single finished part to the process for assembling notebook computers. During that process, the heatpipe hinge radiation mechanism  14  is first built into a housing  15  which constitutes the outer shell of the display part  12  together with the LCD  13  and other components so as to be integral with the display part  12 . The fixed plate  22  of the heatpipe hinge radiation mechanism  14  integral with the display part  12  is fixed to the chassis (not shown) in the body  10  and thus, the display part  12  is rotationally connected to the body  10 . 
     Therefore, the heatpipe  18  and the heat sink  16  are exposed to the outside until the heatpipe hinge radiation mechanism  14  is built into the body  10  together with the display part  12 . The heat sink  16  is connected to the display part  12  through the heatpipe  18  only. Thus, when any load other than the moment rotating around the axis S acts between the heat sink  16  and the display part  12 , that load will act as a bending or torsional load on the heatpipes  18  and  26 . 
     The heatpipes  18  and  26  are formed of, for example, metal or any other heat conductor such as copper, aluminum, and stainless steel and have a thinner wall to increase heat transfer (endothermic and radiative) speeds near the opposite ends. This will prove that a slight load may easily cause bending, buckling, fracture, or any other breakage, resulting in decreased heat transport capacities or incapacity for heat transport. The display part  12  is handled very carefully during the notebook computer assembly process in order to avoid such breakage of the heatpipe hinge radiation mechanism  14 , but the heatpipes  18  and  26  may be damaged by getting the heat sink  16  snagged on something or imposing an inappropriate load on the heatpipes  18  and  26  during the transportation of the display part  12  or its assembly into the body  10 . In addition, when the display part  12  is removed from the body  10  for repair of the notebook computer, the heatpipes  18  and  26  of the display part  12  removed from the body  10  may be easily damaged. 
     The display part  12  is usually held on a tray or pallet or in a storage container corresponding to its shape until it is incorporated with the body  10 . However, the storage container may be complicated if it is intended to prevent an inappropriate load from being imposed on the heatpipes  18  and  26 , resulting in a large space required to hold the display part  12  together with the storage container and difficulty in efficiently transporting the display part  12  together with the storage container. 
     SUMMARY OF THE INVENTION 
     An embodiment of the present invention is a radiation structure applicable to electronic equipment such as a notebook-type personal computer, word processor, or PDA (Personal Data Assistant) with a body and a display part, which comprises a first heatpipe for transferring heat from a heating element contained in the body; a hinge member connected to the first heatpipe for receiving heat from the first heatpipe; a second heatpipe for transferring heat from the hinge member to a radiation member placed in the display part, one end of the second heatpipe arranged substantially coaxially with respect to the center of rotation of the display part being connected to the hinge member rotationally with respect thereto; and a sleeve member arranged in the hinge member coaxially with respect to the center of rotation of the display part, the sleeve member being inserted from the outside into the inside of the display part together with a portion of the second heatpipe which projects from the hinge member. 
     According to the radiation structure as configured above, when the hinge member is built into the display part together with the second heatpipe, the second heatpipe will not be exposed to the outside between the hinge member and the display part. Therefore, the second heatpipe can be protected from any breakage which may be caused by something hitting against the second heatpipe before the display part is incorporated with the body together with the first heatpipe and the hinge member. 
     In the radiation structure as configured above, since the sleeve member can be supported by the display part rotationally around the center of rotation of the display part, any external load acting on the hinge member and the display part will not affect directly the second heatpipe because the load is supported by the sleeve member. Therefore, it the sleeve member has a sufficiently high rigidity, the second heatpipe can be prevented from being broken even when any external load is imposed on the hinge member and the display part. 
     In the radiation structure as configured above, since the hinge member can be divided into a first hinge to which the first heatpipe is connected and a second hinge to which the second heatpipe is connected rotationally with respect thereto and which has the sleeve member provided therewith and is connected to the first hinge, no external load will affect directly the first heatpipe if the second heatpipe is built into the display part and the first hinge is built into the body so that the first heatpipe is supported by the body and the first hinge before the display is incorporated with the body. Therefore, the first heatpipe can be prevented from being broken under any external load when the display part is incorporated with the body. 
     The radiation structure as configured above can also transfer heat from the heat element in the body to the display part through heat conduction even if a first heat conductor and a second heat conductor both of which are made of a material with a sufficiently high heat conductivity are substituted for the first heatpipe and the second heatpipe, respectively. In this case, the first and second heat conductors can be made of various materials including, for example, metal materials such as copper and aluminum and nonmetallic materials which have a sufficiently high heat conductivity. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view for showing the configuration of a heatpipe hinge radiation mechanism according to an embodiment of the present invention; 
     FIG. 2 is a perspective view for showing that the heatpipe hinge radiation mechanism according to an embodiment of the present invention is built into a notebook computer; 
     FIG. 3 is a perspective view for showing that a pair of hinges in the heatpipe hinge according to an embodiment of the present invention are disassembled; 
     FIG. 4 is a cross section for showing a connection between the display part an the heatpipe hinge according to an embodiment of the present invention; and 
     FIG. 5 is a perspective view for showing another heatpipe hinge radiation mechanism according to the prior art, which is currently finding wide application in notebook computers. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Now, a heatpipe hinge radiation mechanism according to an embodiment of the present invention will be described below with reference to the drawings. 
     FIGS. 1 and 2 show a heatpipe hinge radiation mechanism according to an embodiment of the present invention. The heatpipe hinge radiation mechanism  40  is applicable to a notebook computer  46  having a body  42  and a display part  44  as shown in FIG.  2  and transfers heat produced in the body  42  to the display part  44  to suppress any temperature rise within the body  42  and on the outer surface of the body  42 . 
     In the notebook computer  46 , the display part  44  is connected to the body  42  by a pair of hinges  48  as shown in FIG. 2, which allows the body  42  and the display part  44  to rotate around the axis S with respect to each other. The hinges  48  function as a friction mechanism to keep the display part  44  at a predetermined angle with respect to the body  42  under no external force. 
     As shown in FIG. 2, the body  42  contains various electronic components such as a CPU  50  which may produce a relatively large amount of heat. The display part  44  is assembled so that a portion of a liquid crystal display part (LCD)  52  which may produce a relatively small amount of heat is exposed to the outside. Thus, only a small portion of the total amount of heat produced during the operation of the notebook computer  46  may be produced within the display part  44  and the remaining large portion of it may be produced by the electronic components in the body  42 . 
     The heatpipe hinge radiation mechanism  40  includes a plate-like heat sink  54  provided within the body  42  and made of aluminum. The heat sink  54  is fixed to a metal chassis  56  in the body  42  and is supported by the chassis  56  above a circuit board (not shown) on which a CPU  50  is to be mounted. The underside of the heat sink  54  is in contact with the top surface of the CPU  50  directly or indirectly through a cushioning material (not shown) with a high thermal conductivity such as silicone rubber. This allows the heat produced from the CPU  50  to be transferred to the heat sink  54  through the cushioning material by means of its heat conduction and then to be stored in the heat sink  54 . It should be noted that the heat transfer from the CPU  50  to the heat sink  54  does not need to be accomplished through heat conduction only and that it may be accomplished through thermal emissivity or convection by means of airspace as a medium or through any combination of heat conduction, thermal emissivity, and convection. 
     On the side edge of the heat sink  54 , a U-shaped groove is formed along the direction of the depth of the notebook computer  46  (as shown by the arrow D in FIG. 2) and one end of a heatpipe  58  in the direction of the length is inserted into the groove and then fixed to it through press fit or caulking. It should be noted that the heatpipe  58  is a pipe made of a metal material having a good heat conductivity (for example, copper, nickel, and stainless steel) and its inside is decompressed to provide a closed space in which pure water is enclosed as operating fluid. With this configuration, the operating fluid is heated at a heating end (one end) of the heatpipe  58  for vaporization and the vapor is cooled at the opposite cooling end (the other end) to return to its fluid state with radiation. Then the operating fluid is returned to the heating end for vaporization again and such a circulation is repeated for heat transport. It should be noted that the operating fluids to be enclosed in the heatpipe  58  vary with the operating temperature and that a low-cost and efficient water is a suitable operating fluid when used for a relatively lower temperature zone (300° C. or lower) as in this embodiment. 
     The heatpipe hinge radiation mechanism  40  includes a heatpipe hinge  60  to connect the body  42  and the display part  44 . The heatpipe hinge  60  is a two-part structure which consists of hinges  62  and  64  arranged on the body  42  and the display part  44 , respectively, as shown in FIG.  3 . It should be noted that the hinges  62  and  64  are formed of a metal material having high heat conductivity such as aluminum or a nonmetallic material having high heat conductivity. 
     As shown in FIG. 3, the hinge  62  is a substantially rectangular plate having the length in the direction of the width of the notebook computer  46  (as shown by the arrow W) and its underside is fixed to the chassis  56 . The hinge  62  has a cylindrical insertion hole  66  formed along the lower edge in parallel relation with respect to the axis S and the other end of the heatpipe  58  is inserted into the insertion hole  66  and fixed to it through caulking or press fit. It should be noted that any space between the internal surface of the insertion hole  66  and the external surface of the heatpipe  58  may be filled with grease of a high heat conductivity to reduce heat transfer resistance between them. In addition, the hinge  62  has three through-holes  68  running through in the direction of its thickness in the upper portion. 
     A tubular pipe holder  70  is integrally formed on the edge of the chassis  56  near the display part  44  and a portion of the heatpipe  58  between the heat sink  54  and the hinge  62  runs through the pipe holder  70 . This configuration allows the heatpipe  58  to be supported by the heat sink  54 , the chassis  56 , and the hinge  62 , resulting in no external load imposed on the heatpipe  58  through the heat sink  54 , the chassis  56 , and the hinge  62 . 
     On the contrary, the hinge  64  of a shape corresponding to the hinge  62  is arranged on the display part  44  as shown in FIG.  3 . The hinge  64  is a substantially rectangular plate which has the upper portion thicker than the lower portion. The hinge  64  has three threaded holes  72  corresponding to the three through-holes  68  in the lower portion and it has a cylindrical insertion hole  74  formed along the direction of the width in the upper portion. 
     A cylindrical sleeve member  76  is integrally formed on the inner side edge of the hinge  64  as shown in FIG.  1 . The sleeve member  76  has a cylindrical cavity  78  formed coaxially therewith in communication with the insertion hole  74  and the inside diameter of the cavity  78  is equal to that of the insertion hole  74 . In addition, the sleeve member  76  is made of the same material as for the hinge  64  and has a sufficiently higher strength than a plastic housing  82 . 
     One end of a heatpipe  79  is rotationally inserted into the insertion hole  74  of the hinge  64  and the cavity  78  of the sleeve member  76  as shown in FIG.  4 . The heatpipe  79  has a similar structure to that for the heatpipe  58  arranged on the body  42 . In addition, the heatpipe  79  has a substantially straight shape and it is supported to be coaxial with the axis S of the hinge  48 . It should be noted that any space between the internal surfaces of the insertion hole  74  and the cavity  78  and the external surface of the heatpipe  79  may be filled with grease of a high heat conductivity to reduce heat transfer resistance and rotational resistance between them. 
     The other end of the heatpipe  79  is connected to a radiation plate  80  as shown in FIG.  2 . The radiation plate  80  is made of a metal material having high heat conductivity such as aluminum, stainless steel, and copper or a nonmetallic material having high heat conductivity and it is fixed to the backside of the LCD  52  in the display part  44 . A pair of tubular connections  81  are integrally formed on the lower edge of the radiation plate  80  and a portion of the heatpipe  79  near its other end is inserted into the pair of connections  81  and fixed to them through caulking. 
     The housing  82  which constitutes the outer shell of the display part  44  includes a hinge receiver  84  upwardly recessed in the lower portion as shown in FIG.  4  and the upper portion of the hinge  48  and the hinge  64  of the heatpipe hinge  60  are stored in the hinge receiver  84 . The inner wall of the hinge receiver  84  of the housing  82  has a support hole  86  formed coaxially with the axis S and a pair of annular bearings  88  and  90  are integrally formed on the inside of the inner wall to be coaxial with the support hole  86 . The sleeve member  76  of the hinge  64  is rotationally inserted into the support hole  86  and the bearings  88  and  90  and the tip of the sleeve member  76  projects from the bearing  90  into the housing  82 . This configuration allows the hinge  64  to be connected to the display part  44  rotationally around the axis S with respect to the display part  44 . In addition, since a portion of the heatpipe  79  which projects from the hinge  64  is inserted into the housing  82  through the sleeve member  76 , a portion between the hinge  64  and the display part  44  is covered with the sleeve member  76  so that it is not exposed to the outside. 
     During the process for assembling the heatpipe hinge radiation mechanism  40 , the hinge  62  of the heatpipe hinge  60 , the heatpipe  79 , and the radiation plate  80  are assembled together with the display part  44  to form a display part unit  92  as shown in FIG.  3  and then the display part unit  92  is incorporated with the body  42 . The incorporation of the display part unit  92  with the body  42  is accomplished by first fastening the pair of hinges  48  to the chassis  56  in the body  42  with screws (not shown), putting screws  94  into the three insertion holes  68  of the hinge  62 , and thrusting the tips of the screws  94  into the three threaded holes  72  of the hinge  64 , respectively, for fastening the hinge  62  to the hinge  64 . This step allows the display part  44  to be connected to the body  42  rotationally around the axis S. It should be noted that any load which may act on the body  42  and the display part  44  is substantially supported by the pair of hinges  48  and no load from the body  42  and the display part  44  will act directly on the heatpipe hinge  60 . 
     It should be further noted that the heatpipe hinge  60  supports the end portion of the heatpipe  58  and the end portion of the heatpipe  79  inserted into the pair of insertion holes  66  and  74 , respectively, so that both heatpipes  58  and  79  are substantially parallel to each other and sufficiently closer to each other. This configuration allows a sufficiently large amount of heat to be transferred by the heatpipe hinge  60  in a unit time. More specifically, the distance between the two heatpipes  58  and  79  can set such that the amount of heat transferred by the heatpipe hinge  60  in a unit time approximates to the amount of heat transported by the heatpipe  58  in a unit time. It should also be noted that, if required, any space between the contacting surfaces of the hinges  62  and  64  may be filled with grease of a high heat conductivity to minimize the heat transfer resistance from the hinge  62  to the hinge  64 . 
     In the heatpipe hinge radiation mechanism  40  as configured above, any heat produced by the CPU  50  and other electronic components in the body  42  during the operation of the notebook computer  46  is absorbed by the heat sink  54 . The heat stored in the heat sink  54  is transferred to the heatpipe hinge  60  through the heatpipe  58  and then transferred to the heatpipe  79  through heat conduction in the heatpipe hinge  60 . That heat is further transferred to the radiation plate  80  through the heatpipe  79 . Then, the heat from the heatpipe  79  spreads in the radiation plate  80  from the lower portion near the connection  81  to the upper portion and is emitted into the display part  44  through thermal emissivity. This allows the heat produced by the CPU  50  and other components in the body  42  to be efficiently transferred through the heatpipe hinge radiation mechanism  40  into the display part  44  which is lower than the inside of the body  42  in temperature and thus, any excessive rise in temperature can be avoided both within the body  42  and on the outer surface of the body  42 . 
     In the heatpipe hinge radiation mechanism  40  according to this embodiment as described above, when the hinge  64 , the heatpipe  79 , and the radiation plate  80  have been assembled together with the display part  44 , no external load imposed on the hinge  64  and the display part  44  will act directly on the heatpipe  79  because the load is supported by the sleeve member  76 . In addition, since a portion of the heatpipe  79  which projects from the hinge  64  is covered with the sleeve member  76 , no external load imposed on the hinge  64  and the display part  44  will cause the heatpipe  79  to be broken and a portion of the heatpipe  79  between the heatpipe hinge  60  and display part  44  will not be exposed to the outside. Therefore, the heatpipe  79  can be protected from any breakage which may be caused by an inappropriate load imposed on the heatpipe  79  or something hitting against the heatpipe  79  before the display part unit  92  is incorporated with the body  42 . It should be noted that a plastic bush with a good sliding capability may be used to cover the outer surface of the sleeve member  76  if abnormal sound is produced through friction between the sleeve member  76  and a portion of the housing  82  during the rotational movement of the display part  44 . 
     Moreover, in the heatpipe hinge radiation mechanism  40 , only the hinge  64 , the heatpipe  79 , and the radiation plate  80  may be preassembled into the display part  44  and the remaining hinge  62 , the heatpipe  58 , and the heat sink  54  may be preassembled into the body  42 . Therefore, no load of the display part  44  will act on the heatpipe  58  during the storage or transportation. In addition, since the heatpipe  58  can be supported by the hinge  62 , the chassis  56 , and the heat sink  54 , the heatpipe  58  can be protected from any breakage which may be caused by a load imposed on the display part  44  and the body  42 . 
     From the foregoing, the radiation structure for electronic equipment according to the present invention can protect the heatpipe from any breakage which may be caused during its storage, transportation, or assembly before it has been built into the electronic equipment and also allow any heat produced in the body to be efficiently transferred to the display part.