Abstract:
A heat conducting apparatus includes a heat pipe and a heat pipe supporting mechanism. The heat pipe conducts heat between a first member and a second member connected by hinge sections. The heat pipe has a first end portion attached to one of the first and second members and a second end portion extending substantially along a center line of the hinge sections. A heat pipe supporting mechanism is disposed on a member different from the one of the first and the second members of the heat pipe. The heat pipe supporting mechanism supports the second end portion so that the second end portion can freely move within a given range. The heat pipe supporting mechanism forms a thermal path between the first and second members together with the heat pipe.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a heat conducting apparatus and an electronic apparatus having such a heat conducting apparatus. 
     Notebook computers are required to have multi-function, high performance, high density and high speed. For the above requirement, it is essential to enhance the performance of a central processing unit (CPU) or the like incorporated therein. However, the enhancement of the performance of a CPU entails an increased generation of heat therefrom, thus requiring more efficiency than ever in the even diffusion and the radiation of heat. It is preferable to employ a heat pipe for achieving such efficiency. 
     A notebook computer includes a main unit containing a CPU, a keyboard and so on and a separate liquid crystal display section which rotates on a hinge section and can be opened up from or closed down to the main unit. The liquid crystal display section is opened at the beginning and closed in the end of the use of the notebook computer. This folding action of the liquid crystal display section is repeated while the notebook computer is in use. Therefore, when the notebook computer is used over a long period of time, the frequent folding action of the liquid crystal display section causes the hinge section to be worn down and have a play therein, with the result that the center of the hinge section sometimes moves, though slightly, during the folding action of the liquid crystal display section. The incorporation of a heat pipe into a notebook computer requires careful consideration of the above described structure of a notebook computer. 
     2. Description of the Related Art 
     Japanese Laid-Open Patent Application Nos. 9-6481 and 9-16289 disclose conventional notebook computers wherein a heat pipe is incorporated to transmit heat generated from a CPU within a main unit to a liquid crystal display section for the purpose of the even diffusion and the radiation of heat. 
     In the aforementioned notebook computers, the heat pipe runs through the center of the hinge section connecting the main unit and the liquid crystal display section. The heat generated from the CPU within the main unit is transmitted through a metal plate to the heat pipe inserted into the hinge section. The heat is further conducted through the heat pipe to a heat radiating plate within the liquid crystal display section to be radiated to the outer air. 
     Japanese Laid-Open Patent Application No. 9-293985 discloses a notebook computer including: a main unit provided with hinge sections on its rear portion; a liquid crystal display section hinged to the main unit; cooling fins attached to a heat radiating portion of a heat pipe; and the heat pipe having its one end portion disposed in the liquid crystal display section. 
     In the notebook computers disclosed in Japanese Laid-Open Patent Application Nos. 9-6481 and 9-16289, force caused by the folding action of the liquid crystal display section and the load of the liquid crystal display are directly exerted on the heat pipe. Therefore, there is a danger that the heat pipe may be broken in the worst case as a result of the forced bend of its portion. 
     Further, the connection of the main unit and the liquid crystal display section becomes complicated because the heat pipe runs through the hinge section. 
     In the notebook computer disclosed in Japanese Laid-Open Patent Application No. 9-293985, the heat is not transmitted efficiently from the heat radiating portion of the heat pipe to the liquid crystal display section. Therefore, the efficiency in the even diffusion and the radiation of heat is not achieved. 
     SUMMARY OF THE INVENTION 
     A general object of the present invention is to provide a heat conducting apparatus and an electronic apparatus having such a heat conducting apparatus in which the above described problems are eliminated. 
     A more specific object of the present invention is to provide a heat conducting apparatus achieving more efficiency in the even diffusion and the radiation of heat without damaging or breaking a heat pipe employed therein, and an electronic apparatus having such a heat conducting apparatus. 
     The above objects of the present invention are achieved by a heat conducting apparatus including: a heat pipe which conducts heat between a first member and a second member connected by hinge sections, the heat pipe having a first end portion attached to one of the first and second members, and a second end portion extending substantially along a center line of the hinge sections; and a heat pipe supporting mechanism which is disposed on a member different from the one of the first and second members of said heat pipe and supports the second end portion so that the second end portion can freely move within a given range, the heat pipe supporting mechanism forming a thermal path between the first and second members together with the heat pipe. Hence, the second end portion of the heat pipe is allowed to move in accordance with the movement of the center of the hinge sections when the first member is rotated to be opened or closed with respect to the second member, causing no bending stress to develop within the heat pipe. Therefore, it is possible to prevent the heat pipe from being damaged or broken. 
     The above objects of the present invention are also achieved by an electronic apparatus having a first housing and a second housing connected by hinge sections, the electronic apparatus comprising: a heat pipe which has a first end portion disposed on one of the first and second housings, and a second end portion extending along a center line of said hinge sections; and a heat pipe supporting mechanism which is disposed on a housing different from the one of the first and second housings of the heat pipe and supports the second end portion so that the second end portion can freely move within a given range, the heat pipe supporting mechanism forming a thermal path between the first and second housings together with the heat pipe. Hence, the second end portion of the heat pipe is allowed to move in accordance with the movement of the center of the hinge sections when the first housing is rotated to be opened or closed with respect to the second housing, causing no bending stress to develop within the heat pipe. Therefore, it is possible to prevent the heat pipe from being damaged or broken and to realize an electronic apparatus having more efficiency in the even diffusion and the radiation of heat. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which: 
     FIG. 1 is an exploded view of a heat conducting apparatus according to a first embodiment of the present invention; 
     FIG. 2 is an enlarged cross section along the II—II line of the heat conducting apparatus of FIG. 1; 
     FIG. 3 is an enlarged, exploded view of the heat conducting apparatus of FIG. 1; 
     FIG. 4 is a perspective view of a notebook computer wherein the heat conducting apparatus of FIG. 1 is employed; 
     FIG. 5 is an enlarged view of the heat conducting apparatus and the hinge sections of the notebook computer of FIG. 4 without a keyboard section; 
     FIG. 6 illustrates the flexibility of a cylindrical portion; 
     FIG. 7 illustrates the flexibility of the cylindrical portion; 
     FIG. 8 illustrates a movement of the cylindrical portion when the center of the hinge sections moves during the folding action of a liquid crystal display section; 
     FIG. 9 illustrates a movement of the cylindrical portion during the folding action of the liquid crystal display section when the center of the cylindrical portion does not correspond to the center of the hinge sections; 
     FIG. 10 illustrates a heat conducting apparatus according to a second embodiment of the present invention; 
     FIG. 11 illustrates a heat conducting apparatus according to a third embodiment of the present invention; 
     FIG. 12 illustrates a heat conducting apparatus according to a fourth embodiment of the present invention; and 
     FIG. 13 illustrates a heat conducting apparatus according to a fifth embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 4 depicts a notebook computer  10  as an electronic apparatus having a heat conducting apparatus  30  according to a first embodiment of the present invention. The notebook computer  10  includes a main unit  11  and a liquid crystal display section  12 . The main unit  11  serves as a first housing of the notebook computer and the liquid crystal display section  12  serves as a second housing thereof. The liquid crystal display section  12  is connected rotatably to the main unit  11  by means of hinge sections  13  and  14  arranged on each rear corner of the main unit  11  so as to freely be opened and closed with respect to the main unit  11 . In FIG. 5, CL 1  indicates the center line of the hinge sections and O 1  indicates the center of the hinge sections  13  and  14 . 
     The main unit  11  is equipped on its upper surface with a keyboard  16  as shown in FIG.  4  and incorporates therein, as shown in FIGS. 1 and 2, a base plate  17 , a printed circuit board  18 , a CPU  19  as a heating body and so on. The base plate  17  is a thin aluminum plate as thick as about 1 mm. The upper surface of a block  20  is thermally bonded to the bottom surface of the base plate  17  and the bottom surface of the block  20  is held in thermal contact with the top of the CPU  19 . The liquid crystal display section  12  is provided on its front face with a liquid crystal display  25 , which has a heat radiating plate  26  on its rear side as shown in FIGS. 1 and 2. 
     Herein will be described a heat conducting apparatus  30 . 
     The heat conducting apparatus  30  includes a heat pipe  31  and a heat pipe supporting mechanism  32  as shown in FIGS. 1,  2  and  5 . 
     As depicted in FIG. 3, the U-shaped heat pipe  31  includes two parallel linear portions  31   a  and  31   b  joined by an arch portion  31   c . For example, the heat pipe  31  has an outside diameter of 3 mm and a thickness as thin as 0.3 mm. The arch portion  31   c  has a long radius R 1  of about 10 mm so that it can absorb a bending stress generated when the heat pipe  31  is bent. A linear portion  31   a  of the heat pipe  31  is fixedly disposed in a cylindrical portion  26   a , which is formed by rounding the edge of the heat radiating plate  26 . Another linear portion  31   b  remains external in a predetermined position with respect to the heat radiating plate  26 . 
     The heat pipe supporting mechanism  32  includes, as shown in FIGS. 2 and 3, a steplike bent portion  33 , which is formed on the edge of the base plate  17 , an upright wall portion  34 , a concave slot portion  35  and a holding member  36 . 
     The steplike bent portion  33 , which is bent to form a steplike figure, includes a vertical plate portion  33   a  and a lateral plate portion  33   b . The upright wall portion  34  stands in a Z 1  direction from the edge of the lateral plate portion  33   b . The concave slot portion  35  has a cross section of a semicircular figure and is formed on the upright wall portion  34  to extend in an X 1 -X 2  direction. As this base plate  17  is a thin aluminum plate, the steplike bent portion  33  is elastically deformed easily by small force in the same direction as widen or narrow an angle α formed between the vertical plate  33   a  and the lateral plate  33   b , an angle β formed between the base plate  17  and the vertical plate  33   a , and an angle θ formed between the lateral plate  33   b  and the upright wall portion  34 . 
     The holding member  36  has a hook portion  36   a  formed on the top end, a concave slot portion  36   b  having a cross section of a semicircular figure, and a plate portion  36   c  divided into smaller plates. The holding member  36  has the hook portion  36   a  hooked over the top of the upright wall portion  34  with the plate portion  36   c  being coupled to the upright wall portion  34  by screws  37 . 
     The aforementioned steplike bent portion  33  and the holding member  36  include a movement accommodating portion of the heat pipe supporting mechanism  32 . 
     The concave slot portion  35  and the concave slot portion  36   b  are disposed so as to face each other, forming a cylindrical portion  38  extending in the X 1 -X 2  direction. The linear portion  31   b  of the heat pipe  31 , with its surface coated with grease  39 , is inserted into this cylindrical portion  38 . This cylindrical portion  38  includes a holding portion of the heat pipe supporting mechanism  32 . 
     The heat pipe supporting mechanism  32  forms a thermal path, through which the heat generated from the CPU  19  is conducted to the heat radiating plate  26  by way of the block  20 , the base plate  17 , the steplike bent portion  33 , the cylindrical portion  38 , a layer of the grease  39  and the heat pipe  31 , thus realizing the efficiency in the even diffusion and the radiation of heat. 
     The heat radiating plate  26  is incorporated into the liquid crystal display section  12  with its rounded bottom edge holding tightly the linear portion  31   b  of the heat pipe  31 . This structure allows the linear portion  31   b  of the heat pipe  31  to appear from the bottom edge of the liquid crystal display section  12  as shown in FIG.  4 . The linear portion  31   b  of the heat pipe  31  is supported by the heat supporting mechanism  32  first by connecting the liquid crystal display section  12  and the main unit  11  by means of the two hinge sections  13  and  14  disposed on each rear corner of the main unit  11 , and then by coupling the holding member  36  to the upright wall portion  34  by the screws  37 . The linear portion  31   b  of the heat pipe  31  fits in with the concave slot portion  35  formed on the upright wall portion  34  with the liquid crystal display section  12  being connected to the main unit  11  by means of the two hinge sections  13  and  14 . The holding member  36  maybe attached so as to cover the linear portion  31   b  of the heat pipe  31 . Supporting the linear portion  31   b  of the heat pipe  31  through the heat pipe supporting mechanism  32  is thus facilitated. 
     The heat pipe supporting mechanism  32  is disposed between the two hinge sections  13  and  14  arranged on each rear corner of the main unit  11  and is covered with a cover  41  having a semi-cylindrical shape. The cover  41  forms a part of the main unit  11 . 
     Herein will be described the flexibility of the cylindrical portion  38  by referring to FIGS. 5,  6  and  7 . 
     CL 2  indicates the center line of the cylindrical portion  38  and O 2  indicates the center of the cylindrical portion  38 . 
     For example, as depicted by dotted lines in FIG. 6, the center of the cylindrical portion  38  is movable in a Y 1 -Y 2  and a Z 1 -Z 2  directions according as the steplike bent portion  33  is deformed in the same direction as widen or narrow the angles α, β, and θ. 
     Further, the cylindrical portion  38 , which includes the upright wall portion  34  and the holding member  36 , can bulge toward a Y 2  direction, for the holding member  36  deforms in the opposite direction from the upright wall  34  as depicted by dotted lines in FIG. 7 since the holding member  36  is fixed to the upright wall portion  34  by the screws  37 , which are not disposed very close to, but are disposed at a distance in a Z 1 -Z 2  direction from the cylindrical portion  38 . 
     Herein will be described a movement of the linear portion  31   b  of the heat pipe  31  when the liquid crystal display section  12  is rotated to be opened or closed with respect to the main unit  11 . 
     (1) In case the center O 1  of the hinge sections  13  and  14  moves in a Y 1 -Y 2  and a Z 1 -Z 2  directions. 
     The liquid crystal display section  12  and the heat pipe  31  move in conformity with the hinge sections  13  and  14 , and the movement of the linear portion  31   b  of the heat pipe  31  is transmitted to the cylindrical portion  38 . Then, as depicted by dotted lines in FIG. 8, the steplike bent portion  33  and the holding member  36  are deformed, allowing the cylindrical portion  38  to move in accordance with the movement of the center of the hinge sections  13  and  14 . 
     Therefore, the linear portion  31   b  of the heat pipe  31  rotates within the cylindrical portion  38  with its center O 3 , together with the cylindrical portion  38 , moving in accordance with the movement of the center O 1  of the hinge sections  13  and  14 . As the surface of the linear portion  31   b  of the heat pipe  31  is coated with the grease  39 , the linear portion  31   b  rotates smoothly within the cylindrical portion  38  without wear. 
     Therefore, as the linear portion  31   b  of the heat pipe  31  is so supported by the heat pipe supporting mechanism  32  as to move without restraints, the heat pipe  31  itself is not subject to a bending pressure, generating no bending stress from within, which prevents the heat pipe  31  from being damaged or broken. 
     (2) In case the center O 3  of the linear portion  31   b  of the heat pipe  31 , or the center O 2  of the cylindrical portion  38 , moves by δ with respect to the center O 1  of the hinge sections  13  and  14 . 
     According to the design of the heat pipe supporting mechanism  32 , the center O 3  of the linear portion  31   b  of the heat pipe  31 , or the center O 2  of the cylindrical portion  38 , should correspond to the center O 1  of the hinge sections  13  and  14 . Practically, however, an error in the assembly of the hinge mechanism  32 , a change in the hinge mechanism  32  with the passage of time since the beginning of its use, and so on sometimes cause the center O 3  of the linear portion  31   b  of the heat pipe  31 , or the center O 2  of the cylindrical portion  38 , to move by δ, as shown in FIG. 9, with respect to the center O 1  of the hinge sections  13  and  14 . 
     When the liquid crystal display is rotated, the center of the linear portion  31   b  of the heat pipe  31  starts to move along an arc  40  having a radius of δ of the center O 1  of the hinge sections  13  and  14 . Then, the steplike bent portion  33  and the holding member  36  are deformed so as to allow the cylindrical portion  38  to move in accordance with the movement of the linear portion  31   b  of the heat pipe  31 , namely, to move along the arc  40 . 
     Therefore, the linear portion  31   b  of the heat pipe  31  rotates within the cylindrical portion  38 , moving, together with the cylindrical portion  38 , along the arc  40 . As the surface of the linear portion  31   b  of the heat pipe  31  is coated with the grease  39 , the linear portion  31   b  rotates smoothly within the cylindrical portion  38  without wear. 
     Therefore, as the linear portion  31   b  of the heat pipe  31  is so supported by the heat pipe supporting mechanism  32  as to move without restraints, the heat pipe  31  itself is not subject to a bending pressure, generating no bending stress from within, which prevents the heat pipe  31  from being damaged or broken. 
     The amount of force required to deform the steplike bent portion  33  and the holding member  36  increases as the amount of deformation increases. Therefore, it sometimes happens that the heat pipe  31  is bent to some degree depending on the extent of the movement of the linear portion  31   b  of the heat pipe  31 . However, the heat pipe  31  is prevented from being broken during the repetitive folding actions of the liquid crystal display section  12  since the arch portion  31   c  has the long radius R 1  of about 10 mm such that a bending stress will not concentrate on a bend point of the heat pipe  31 . 
     Herein will be described other embodiments of the present invention. 
     FIG. 10 depicts a heat conducting apparatus  30 A according to a second embodiment of the present invention. A rubber member  50  of a good thermal conductivity is attached to a base plate  17 A. The linear portion  31   b  of the heat pipe  31  is attached to the rubber member  50 . 
     FIG. 11 depicts a heat conducting apparatus  30 B according to a third embodiment of the present invention. Attached to a base plate  17 B is a flexible member  60  of a good thermal conductivity, which deforms without restorability. The linear portion  31   b  of the heat pipe  31  is attached to the flexible member  60 . 
     FIG. 12 depicts a heat conducting apparatus  30 C according to a fourth embodiment of the present invention. A steplike figure portion  26 C b  is formed on the edge of a heat radiating plate  26 C, and the linear portion  31   a  of the heat pipe  31  is fixedly disposed in a cylindrical portion formed on the edge of the steplike figure portion  26 C b . The elastic deformation of the steplike figure portion  26 C b  allows the linear portion  31   a  of the heat pipe  31  to move to some extent. By means of this structure, the movement of the linear portion  31   b  of the heat pipe  31  during the folding action of the liquid crystal display section  12  is absorbed by the deformation of the steplike bent portion  33  and the steplike figure portion  26 C b . Therefore, the movement of the linear portion  31   b  of the heat pipe  31  can be absorbed to a greater extent, thus preventing the arch portion  31   c  of the heat pipe  31  from being bent even if the linear portion  31   b  of the heat pipe  31  moves considerably during the folding action of the liquid crystal display section  12 . 
     FIG. 13 depicts a heat conducting apparatus  30 D according to a fifth embodiment of the present invention. The printed circuit board  18  is fixed to a chassis  101  by a screw  100 . The screw  100  fits loosely in an aperture  18   a  in the printed circuit board  18 , permitting the printed circuit board  18  to freely move within a small area with respect to the chassis  101 . Therefore, a base plate  17 C, together with the CPU  19 , the block  20 , and the printed circuit board  18 , is allowed to freely move within a small area when external force is exerted on the base plate  17 C. The linear portion  31   b  of the heat pipe  31  is rotatably supported on the edge of the base plate  17 C. 
     During the folding action of the liquid crystal display section  12 , the base plate  17 C moves in accordance with the movement of the linear portion  31   b  of the heat pipe  31 . Therefore, no bending stress is generated within the heat pipe  31 . 
     The present invention is not limited to the specifically disclosed embodiments, and variations and modifications may be made without departing from scope of the present invention. 
     The present application is based on Japanese priority application no. 11-122372 filed on Apr. 28, 1999, the entire contents of which are hereby incorporated by reference.