Abstract:
The apparatus provided with a heatsink ( 21 ) being in contact with an electronic component ( 16 ), a heat radiation plate ( 20 ) for radiating heat, a heat conduction member ( 22 ) for transferring heat in the heat sink to the radiation plate, and connection mechanisms ( 21 - 1  and  21 - 2 ) for connecting the heat sink and the heat conduction member and separating the heat sink and the heat conduction member. This connection mechanism enables to maintain small heat conduction resistance between the heat sink and the electronic component and also between heat sink and heat conduction member. Cooling capability can be prevented from decreasing even when the heat sink and the heat conduction member is of separated construction.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a cooling mechanism, a heat sink and an electronic equipment for cooling an electronic component such as CPU or other heat generating elements and a fabrication method for the electronic equipment, and more particularly a cooling mechanism, a heat sink and an electronic equipment on which most suitable cooling mechanism can be mounted corresponding to the amount of the heat generated by an electronic component or other heat generating elements, and a fabrication method for the electronic equipment. 
     2. Description of the Related Art 
     Downsizing of electronic equipment such as a computer and the like having CPU have been remarkably improved with an increased performance. A heat is generated while an electronic component such as a CPU is in operation. Failure of heat dissipation from the electronic component may cause deteriorated performance of electronic components or in some cases result in a failure of the component itself. Cooling mechanism is required to prevent such condition. As electronic equipment is becoming smaller in size in recent years, a cooling space becomes narrower. Therefore cooling mechanism having high performance is desired. 
     Conventionally a heat sink has been used for a cooling mechanism of an electronic component such as a CPU (for example, as disclosed in Japanese Unexamined Patent Publication No. Hei-8-316384.) A heat sink is closely attached to the surface of an electronic component to dissipate heat therefrom. Either a cooling fin or both cooling fin and cooling fan are often used to improve the cooling capability. 
     However, when the electronic component produces large amount of heat, it is insufficient if heat sink only is used. For this reason, there has been proposed a method of using of an equipment frame which have a plate of large radiation area. The heat transferred in the heat sink is further transferred to a radiation plate (as an auxiliary cooling member) through a conduction member (for example, as disclosed in Japanese Unexamined Patent Publication No. Hei-10-107468). According to the disclosure, there is proposed a heat sink configured by a radiation plate to be pushed onto a CPU with a heat conduction member having resilient property. 
     In recent years, information processing equipment such as a notebook computer, desk-top PC, etc. has a high performance CPU which produces different heat amount (or consumes different power amount) depending on the operation frequency thereof. For example, a CPU having an operation frequency of 366 MHz (e.g. Intel Celeron 366) consumes power of approximately 9 W (watts), while another CPU having an operation frequency of 650 MHz (e.g. Intel P III 650) consumes power of approximately 14 W. 
     Meanwhile, low cost is strictly required for such information processing equipment. If a cooling mechanism corresponding to the highest power consumption among a series of CPUS is applied to a CPU which consumes small power, the equipment cost is undesirably increased. Therefore a cooling mechanism fit for the power consumption of a CPU in use is desirably applied. In addition, it is also desirable that major components of a cooling mechanism can be assembled at a later stage in order to meet a BTO (build-to-order) requirement in manufacturing information processing equipment. 
     In the conventional art, when a heat sink and a heat conduction pipe are separately configured, it is possible to select proper combination of a heat sink and a heat conduction pipe corresponding to the CPU capability. However, there is a problem that it is difficult to make the heat sink in surface contact with the CPU because this contact is comprised of that the heat conduction pipe itself pushes the heat sink toward the CPU. Such configuration results in inefficient thermal absorption against heat from the CPU. 
     Also, there is another problem, because a contact area between the heat sink and the heat conduction pipe is small, the heat in the heat sink is not efficiently transferred to the heat conduction pipe. Therefore cooling capability provided in the cooling mechanism cannot fully be utilized. This also results in difficulty to apply a low cost cooling mechanism for a CPU of low power consumption. To sum up, the problem hitherto is that the cost reduction is difficult when a separate configuration is applied. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a cooling mechanism, a heat sink and an electronic equipment and a fabrication method of the electronic equipment, by which a decrease of the cooling capability is prevented even when a separated cooling mechanism is applied. 
     It is another object of the present invention to provide a cooling mechanism, a heat sink and an electronic equipment and a fabrication method of the electronic equipment, enabling to select a cooling mechanism fit for the power consumption of a electronic component. 
     It is still another object of the present invention to provide a cooling mechanism, a heat sink and electronic equipment and a fabrication method of the electronic equipment, enabling to reduce cost even in cooling mechanism of separate configuration. 
     In order to perform this object, a cooling mechanism of an electronic component and an electronic equipment according to the present invention includes: a heat sink being in contact with heat generating electronic component; a heat radiation plate for radiating heat; a heat conduction member for transferring the heat from the heat sink to the heat radiation plate; and a connection mechanism for connecting the heat sink and the heat conduction member and separating the heat sink and the heat conduction member. 
     According to an aspect of the present invention, a connection mechanism is provided for connecting the heat sink and the heat conduction member to be able to separate mutually. This enables the heat sink to be in surface contact independently to a heat-generating electronic component, to reduce thermal resistance between the heat sink and the electronic component. Also, the connection mechanism can reduce thermal resistance between the heat sink and the heat conduction member, enabling to prevent from deteriorating cooling capability even the heat sink is configured separately with the heat conduction member. 
     Therefore, a cooling mechanism fit for consumed power of an electronic component mounted to electronic equipment can be provided with low cost, even configured with a separated structure. In addition, a cooling mechanism provided with removable configuration by the connection mechanism enables easy exchange of an electronic component for grade-up or a heat sink after the equipment is shipped. 
     Further, the connection mechanism according to the present invention is provided to connect the heat sink and the heat conductive member such that the heat sink rotates around the heat conduction member, thereby enabling to exchange or mount the electronic component without removing the heat sink and the heat conduction member. This enables to exchange or mount the electronic component maintaining thermal transfer resistance between the heat sink and the heat conduction member of a manufacturing stage. 
     Still further, in the electronic equipment and the cooling mechanism according to the present invention, the connection mechanism is provided with support members for supporting the heat conduction member, and a pressing member removably provided against the support members for maintaining the heat conduction member between the support members. The fabrication method of the present invention includes the steps of; setting the heat conduction member of equipment frame to mount the electronic component, and attaching the removable heat conduction member to a support portion of the heat sink. By providing the support portion, thermal conduction resistance between the heat sink and the heat conduction member can be kept small when connection is made therebetween. 
     Also, in the electronic equipment, the heat sink and the cooling mechanism according to the present invention, the support portion is constructed integrally with the heat sink. This enables to reduce thermal conduction resistance between the heat sink and the heat conduction member, as well as the reduced number of component even if the connection mechanism is provided. 
     Further scopes and features of the present invention will become more apparent by the following description of the embodiments with the accompanied drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top plan view of electronic equipment according to an embodiment of the present invention. 
     FIG. 2 is a cross-sectional view of A—A of the equipment shown in FIG.  1 . 
     FIG. 3 is a perspective view of an equipment frame shown in FIG.  2 . 
     FIG. 4 is a diagram illustrating a heat sink mounted on the equipment frame shown in FIG.  2 . 
     FIG. 5 is a configuration diagram of a connection mechanism shown in FIG.  4 . 
     FIG. 6 is a cross-sectional view of the connection mechanism shown in FIG.  4 . 
     FIG. 7 is a connection diagram of the equipment frame and heat conduction pipe shown in FIG.  3 . 
     FIG. 8 is a diagram illustrating the heat sink and CPU mounted on the equipment frame shown in FIG.  2 . 
     FIG. 9 is a cross-sectional view of the mount state shown in FIG.  8 . 
     FIG. 10 is another cross-sectional view of the mount state shown in FIG.  8 . 
     FIG. 11 shows an exchange operation after the shipment. 
     FIG. 12 is a configuration diagram of another embodiment of the connection mechanism. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The preferred embodiments of the present invention are described hereinafter referring to the charts and drawings wherein like numerals or symbols refer to like parts. Explanation on electronic equipment, cooling mechanism and other embodiments is independently described. 
     ELECTRONIC EQUIPMENT 
     In FIG. 1, there is shown a top plan view of electronic equipment according to an embodiment of the present invention. 
     In FIG. 2, an A—A cross-sectional view of the electronic equipment is shown. Here, a notebook type personal computer (notebook PC) is given as an example of the electronic equipment. 
     As shown in FIG. 1, a notebook PC  1  is provided with display portion (LCD)  10 , a resume switch  11 , a keyboard  12  (consisting of a plurality of keys, not shown), a flat-type pointing device  13 , and a covered outer cover panel  14 . In FIG. 1, a flat display (LCD, not shown) which can be open and close is mounted the outer cover panel  14  of computer  1 . 
     As shown in the cross-sectional diagram of FIG. 2, an equipment frame  20  is provided in computer  1 . The equipment frame  20  supports equipment portions as well as improves physical strength of the equipment. The equipment frame  20  also functions as a heat radiation plate, as explained later. 
     In FIG. 2, a printed circuit board  15  is mounted the equipment frame  20 . The printed circuit board  15  is provided with an IC socket to mount a CPU  16 . To dissipate heat generated by CPU  16 , a heat sink  21  is provided in surface contact with CPU  16 . As explained later, heat sink  21  is thermally connected with radiation plate  20  through heat conduction pipe  22 . 
     In such computers, various models having different grade of CPU are provided, such as 366 MHz CPU (e.g. Intel Celeron 366, Intel P II 366) model, 500 MHz CPU (e.g. Intel P III 500) model, 650 MHz CPU (e.g. Intel P III 650) model, etc. Each CPU has different maximum power consumption i.e. approximately 9 W, 11 W and 14 W, respectively. 
     In order to provide heat sink  21  fit for the CPU having the largest power consumption, the heat sink  21  requires a cooling capability of approximately 16 W. In case this heat sink  21  is applied to a CPU having low power consumption (such as 366 MHz CPU), cooling capability becomes excessive. This results in not only higher equipment cost but also larger power consumption for cooling (in the cooling fan). This further makes it difficult to realize a mobile terminal capable of battery operation for long hours. 
     Therefore, it is required to mount a cooling mechanism fit for power consumption of the CPU in the equipment to reduce cost and power consumption for cooling. Namely, the heat sink  21  and the heat conduction pipe  22  are selectably configured to fit for the CPU power consumption, under the condition that an equipment frame is used for radiation plate  20  which is unchangeable. 
     In the above explanation, a notebook PC is taken as an example of the electronic equipment. It may also be applicable for other electronic equipment having a CPU, such as a desk-top computer, a personal digital assistance and so forth. 
     COOLING MECHANISM 
     In FIG. 3, a perspective view of equipment frame (radiation plate)  20  is shown. Further, in FIG. 4 there is illustrated a diagram in which the heat sink  21  is attached to the equipment frame  20  shown in FIG.  3 . FIG. 5 is a configuration diagram of the connection mechanism between the heat sink  21  and the heat conduction pipe  22 . FIG. 6 is a cross-sectional view of the connection mechanism. FIG. 7 is a diagram by which connected state between the heat conduction pipe  22  and the equipment frame  20  is shown. FIG. 8 is an operational diagram thereof. 
     Referring to FIG. 3, there is shown a perspective view from the bottom of the equipment frame  20  in FIG. 2, wherein the heat conduction pipe  22  is provided at an end. As the heat conduction pipe  22 , a shaft material of copper type or heat pipe may selectably be used. As shown in FIG. 7, an end of the heat conduction pipe  22  is secured to the frame  20  by means of a winding portion  20 - 1  of the frame  20 . This enables the heat conduction pipe  22  to be covered by the frame  20 , producing large surface contact area between the frame  20  and the heat conduction pipe  22  with very small heat conduction resistance of, for example, approximately 0.4° C./W. 
     As shown in FIG. 8, the printed circuit board  15  is mounted on the frame  20  shown in FIG. 3, and the CPU  16  is mounted on an IC socket  18  (refer to FIG. 9) provided on this printed circuit board  15 . In FIG. 8, there is shown a card slot mechanism  17  mounted adjacent to the printed circuit board  15 . 
     As shown in FIG. 8, the other end of the heat conduction pipe  22  is extended adjacent to the CPU  16 . As shown in FIG. 3, the heat sink  21  is provided on the CPU  16  and secured to the printed circuit board  15  by a screw  30  at totally four points on the right and left sides. This enables the heat sink  21  to be in surface contact with the CPU  16  thus having a large contact area and small heat conduction resistance against the CPU  16 . For example the heat conduction resistance is approximately 0.5° C./W, which can further be reduced by applying grease etc. onto the contact face. The configuration of the heat sink  21  is explained later. 
     The heat sink  21  is connected with the heat conduction pipe  22  through a connection mechanism. As shown in FIG.  5  and FIG. 6, the heat sink  21  is provided with a support portion  21 - 1  for supporting the heat conduction pipe  22 . This support portion  21 - 1  is constructed integrally with a main body of the heat sink  21 , formed of, for example, copper or aluminum. 
     The support portion  21 - 1  provides a hollow for the housing heat conduction pipe  22 . A pressing member  21 - 2  is provided on the support portion  21 - 1  for sandwiching the heat conduction pipe  22 . The pressing member  21 - 2  is secured to the support portion  21 - 1  with a screw  31 . 
     With this configuration, the support portion  21 - 1  and the pressing member  21 - 2  cover the heat conduction pipe  22 , producing large contact area which reduces thermal conduction resistance between the heat sink  21  and the heat conduction pipe  22  of, for example, approximately 0.4° C./W. In addition, by applying grease etc. onto the contact face, smaller thermal conduction resistance can be obtained. 
     In FIG.  9  and FIG. 10, a diagram of the mounted heat sink is shown. The heat sink  21  shown in FIG. 9 includes a heat receiving plate  21 - 3  in surface contact with CPU  16 , a radiation fin  21 - 6  and a radiation fan  21 - 7 . The radiation fan  21 - 7 , as an example, takes air in from upper area in the figure and exhaust to the horizontal direction so that it is effective to the cool radiation fin  21 - 6 . The heat sink  21  shown in FIG. 10 is provided with the radiation fin  21 - 6  and the heat receiving plate  21 - 3 . 
     As explained above, the heat sink  21  and the heat conduction pipe  22  have a separate structure which enables to configure the heat sink  21  and the heat conduction pipe  22  with an arbitrary combination fit for the power consumption of CPU  16 . For example, when CPU  16  having high power consumption is used, a cooling fin and a cooling fan shown in FIG. 9 is adopted to configure the heat sink  21 . On the other hand, when CPU  16  having low power consumption is used, only cooling fin shown in FIG. 10 is adopted as the heat sink  21 . In addition, it is also possible to provide heat sink having a cooling fan of various cooling capacity. In conclusion, either of the above can be applied as a heat sink. 
     Needless to say, a heat sink having a cooling fan costs higher, and heat sink having greater cooling capability costs even higher. As for a heat conduction pipe, either a copper shaft, a heat pipe or the like are applicable. The heat pipe has higher thermal transmittance and the cost is also higher. Therefore it is possible to provide a suitable heat conduction pipe corresponding to power consumption of CPU  16 . It is also possible to provide a heat sink without a heat conduction pipe. 
     Accordingly, it is possible for electronic equipment to provide with a cooling mechanism having well balanced cost and performance. Also, when BTO (build to order) system is adopted, the number of inventory parts can be reduced because various types of cooling mechanism can be provided by the combinations of the heat sink  21  and the heat conduction pipe  22 . In addition, implementing the cooling mechanism after the fabrication of the equipment is effective in shortening delivery time. 
     Furthermore, because the heat sink and the heat conduction pipe are separatably connected, the heat sink can firmly be contacted with the CPU. This produces a large contact area with a small heat conduction resistance. At the same time, the use of connection mechanism realizes to have a large contact area between the heat sink and the heat conduction area. This also produces small heat conduction resistance for a separated configuration. Accordingly it is possible to minimize loss of cooling capability of the cooling mechanism even in spite of using a separated configuration. Therefore, the cooling mechanism can be realized with a smaller cost. 
     In addition, the heat sink of the present invention is connected to rotate against the heat conduction pipe. Namely, as shown in FIG. 11, by detaching the screw  30  from the heat sink  21  after the shipment of the equipment, the heat sink  21  can be rotated around the heat conduction pipe. Thus CPU  16  is exposed, making it easy to exchange CPU  16 . This facilitates easy replacement of the CPU for upgrading or substitution in the event of fault. 
     At this time, the connection mechanism keeps connection between the heat sink and the heat conduction pipe. Therefore, heat conduction resistance at the time of factory assembling can be maintained. For example, grease applied at the assembly aimed to reduce heat conduction resistance is not lost. Also, because the heat sink is so configured to be separable from the heat conduction pipe, even when using a heat sink with a fan which is apt to become faulty, replacement can be realized merely by detaching screw  31 . 
     Taking examples of the models by use of 366 MHz CPU (e.g. Intel Celeron 366, or Intel P II 366), 500 MHz CPU (e.g. Intel P III 500) and 650 MHz CPU (e.g. Intel P III 650) model, these CPU have different maximum power consumption of 9 W, 11 W and 14 W, respectively. Therefore corresponding to each CPU, a heat sink having fan capabilities of either 12 W, 14 W or 16 W is applied. For a CPU having less power consumption than the aforementioned CPUs, a heat sink having no fan is applied. This brings about an increased battery time usable for the portable equipment because of small power consumption of the heat sink. 
     ANOTHER EMBODIMENT 
     In FIG. 12, a configuration diagram of another embodiment of the present invention is shown. In this figure there is illustrated another example of a connection mechanism between the heat sink  21  and the heat conduction pipe  22 . The heat conduction pipe  22  is inserted to a support portion  21 - 4  provided in the heat sink  21 . A pressing member  21 - 5  formed of a resilient material is inserted to the support portion  21 - 4 . 
     In this example the pressing member  21 - 5  enables to hold the heat conduction pipe  22  resiliently. Therefore, mounting by the screw  31  is not needed, opposed to the example shown in FIG.  5 . This enables easy assembling or detaching. 
     In addition to the embodiments shown above, the following modification is possible in the present invention: 
     (1) As an electronic component, there has been shown a CPU as an example of heat generating portion. It may also be possible to apply this invention to other components, such as an MPU, DSP, IC for power management, IC chip for controlling DC/DC converter, or IC for image processing. (2) In the above explanation, a notebook PC is used as electronic equipment. In the present invention it is also applicable to personal terminal, portable telephone or other electronic equipment. 
     The foregoing description of the embodiments is not intended to limit the invention to the particular details of the examples illustrated. Any suitable modification and equivalents may be resorted to the scope of the invention. 
     The effect of the present invention is summarized below: 
     Because of the provision of connection mechanism for separatably connecting a heatsink with a heat conduction member, the heat sink can be in surface contact with an electronic component independently when the heat sink is separated from the heat conduction member. This enables to reduce heat conduction resistance between the heat sink and the heat conduction member. Also, because of providing the connection mechanism, small heat conduction resistance between the heat sink and the heat conduction member can be maintained. The cooling capability is not reduced even when the heat sink and the heat conduction are separated each other. 
     For the above reason, it is possible to provide with low cost a cooling mechanism which fits power consumption of electronic components in use in spite of the separate configuration. When the BTO (build to order) system is applied, it is possible to provide electronic equipment having a cooling mechanism which fits power consumption of electronic components in use with low cost and in short manufacturing period. In addition, because the cooling mechanism of the invention is configured with removable mechanism, substitution of electronic components either for upgrading or for replacement of the heat sink is easy after the equipment is shipped. 
     Other features and advantages of the invention which fall within the scope of the invention are covered by the appended claims.