Abstract:
An information processing device including a keyboard for inputting characters or the like, a display for displaying the characters or the like input from the keyboard, a printed wiring board on which electronic components for performing process and display control of the characters or the like input from the keyboard are mounted, and a housing for supporting the keyboard, the display, and the printed wiring board. The information processing device further includes a laterally horizontal shaft supported to a rear portion of the housing, a hollow tilt stand pivotably mounted on the shaft to take a retracted position where the tilt stand is horizontally retracted at a bottom portion of the housing and a raised position where the tilt stand is substantially vertically raised to support the housing in its tilted condition, and a fan provided in the tilt stand. The tilt stand has opposed side walls formed with first ventilation holes. The bottom portion of the housing is formed with second ventilation holes. Heat generated from the electronic components is expelled through the first and second ventilation holes to the outside of the device by the fan.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an information processing device, and more particularly to a cooling structure for cooling electronic components in an information processing device such as a notebook personal computer.  
           [0003]    2. Description of the Related Art  
           [0004]    With the recent widespread use of a notebook personal computer especially for improvement in work efficiency, diverse functions have been required for the computer to result in high-density mounting of high-integration electronic components having high heating values on a printed wiring board built in the computer. Furthermore, the requirement for high-speed operation of a CPU causes an increase in power consumption to result in an increase in heating value. Accordingly, it is necessary to efficiently cool such electronic components.  
           [0005]    [0005]FIG. 1 is a perspective view of a notebook personal computer as an information processing device in the prior art. The notebook personal computer shown in FIG. 1 includes a housing  2 , a keyboard  6 , and a display  8  both mounted on the housing  2 . Although not shown, a printed wiring board is mounted in the housing  2 , and electronic components including a CPU are mounted on the printed wiring board. A fan  12  for cooling the electronic components is mounted at a rear end portion of the housing  2 . Further, a tilt stand  14  for adjusting a view angle of the display  8  is provided. A plurality of vent holes  4  are formed through a front wall of the housing  2  to introduce air into the housing  2 , and a ventilation hole  10  is formed at the rear end of the housing  2  to expel the inside hot air. By driving the fan  12 , heat generated from the electronic components, especially from the CPU is forcibly expelled to the outside of the housing  2 .  
           [0006]    However, a sufficient space cannot be defined between the fan  12  and the electronic components in the conventional information processing device because of its reduced size and weight. As a result, an efficient ventilation space for expelling the heat from the electronic components cannot be defined, thus hindering ideal heat dissipation.  
         SUMMARY OF THE INVENTION  
         [0007]    It is therefore an object of the present invention to provide an information processing device which can efficiently expel the heat with an increased ventilation space.  
           [0008]    In accordance with an aspect of the present invention, there is provided an information processing device having electronic components and a housing, the information processing device comprising a hollow tilt stand pivotably mounted on a first shaft to take a retracted position where the tilt stand is horizontally retracted at a bottom portion of the housing and a raised position where the tilt stand is substantially vertically raised to support the housing in its tilted condition; and a fan provided in the tilt stand for expelling heat from the electronic components.  
           [0009]    Preferably, the information processing device further comprises a first terminal connected to a driving section of the fan; a second shaft supported to the rear portion of the housing; a power supply for supplying a supply voltage to the electronic components and the driving portion of said fan; and a switch pivotably mounted on the second shaft and having a second terminal connected to the power supply, the switch being rotatable between a first position where the second terminal is separate from the first terminal in the retracted position of the tilt stand and a second position where the second terminal is kept in contact with the first terminal by pressure of the tilt stand in the raised position thereof.  
           [0010]    Preferably, the information processing device further comprises a projection formed on the tilt stand; clock switching means having a first terminal for inputting a first clock signal, a second terminal for inputting a second clock signal, a third terminal for inputting a control signal, for outputting to the electronic components one of the first clock signal input to the first terminal and the second clock signal input to the second terminal according to the control signal input to the third terminal; a second shaft supported to the rear portion of the housing; a power supply for supplying a supply voltage to the electronic components, the fan, and the clock switching means; and a switch pivotably mounted on the second shaft and having a fourth terminal connected to the power supply, the switch being rotatable between a first position where the switch is separate from the projection of the tilt stand in the retracted position thereof to make separation of the third terminal and the fourth terminal and a second position where the switch is in pressure contact with the projection of the tilt stand in the raised position thereof to make contact of the third terminal and the fourth terminal.  
           [0011]    More preferably, the information processing device further comprises an extensible partition member elongated over the width of the tilt stand in the lateral direction of the housing, the extensible partition member having a front end fixed to the bottom portion of the housing and a rear end fixed to the tilt stand; wherein when the tilt stand is in the retracted position, the extensible partition member is folded to fill a gap defined between the bottom portion of the housing and the tilt stand, whereas when the tilt stand is in the raised position, the extensible partition member is extended to define an optimum ventilation space in cooperation with the bottom portion of the housing and the tilt stand.  
           [0012]    Other objects and features of the invention will be more fully understood from the following detailed description and appended claims when taken with the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a perspective view of an information processing device in the prior art;  
         [0014]    [0014]FIG. 2 is a perspective view of an information processing device according to a preferred embodiment of the present invention;  
         [0015]    [0015]FIG. 3 is a cross section taken along the line  3 - 3  in FIG. 2;  
         [0016]    [0016]FIG. 4 is a cross section taken along the line  4 - 4  in FIG. 3;  
         [0017]    [0017]FIGS. 5A and 5B are block diagrams for illustrating the operation of the information processing device shown in FIG. 2; and  
         [0018]    [0018]FIG. 6 is a vertical sectional view of an essential part of the information processing device shown in FIG. 2, for illustrating the operation thereof. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    A preferred embodiment of the present invention will now be described with reference to the drawings.  
         [0020]    [0020]FIG. 2 is a perspective view of an information processing device according to a preferred embodiment of the present invention. FIG. 3 is a cross section taken along the line  3 - 3  in FIG. 2. FIG. 4 is a cross section taken along the line  4 - 4  in FIG. 3. As shown in FIGS.  2  to  4 , the information processing device includes a housing  20 , a display  22  pivotably supported through a horizontal shaft  25  to the housing  20  at its rear upper portion, a keyboard  24  horizontally supported to the housing  20 , a printed wiring board  30  accommodated in the housing  20 , a tilt stand  26  pivotably supported through a horizontal shaft  28  to the housing  20  at its rear lower portion, and an extensible partition member  35  connected between the housing  20  and the tilt stand  26 . A plurality of vent holes  23  are formed through a front wall of the housing  20 . A plurality of electronic components  32  including a CPU, a power supply  60 , and a clock switching element  62  are mounted on the printed wiring board  30  accommodated in the housing  20 . The CPU having a higher heating value in the electronic components  32  is mounted on the lower surface of the printed wiring board  30  at its rear portion above the tilt stand  26  in its horizontal or retracted position as shown in FIG. 3.  
         [0021]    The housing  20  has a right-angled bottom portion  20   a  opposed to the tilt stand  26  in its retracted position. This bottom portion  20   a  of the housing  20  is formed with a plurality of ventilation holes  31  such as slits. The slits may be formed by cutting a sheet metal or plastic. The tilt stand  26  is a laterally elongated, hollow boxlike member having opposed side walls formed with a plurality of ventilation holes  27  such as slits. The tilt stand  26  is rotatable about  90  degrees about the horizontal shaft  28  supported to the housing  20 . A stopper  38  projects inward from a rear wall of the housing  20 , so as to maintain a substantially vertical or raised position of the tilt stand  26 . A projection  36  is formed at a rear end of the tilt stand  26  in its retracted position so as to project toward the rear wall of the housing  20 . A fan  34  is provided in the tilt stand  26 .  
         [0022]    The fan  34  is constructed as a single fan unit consisting of a driving section and a rotating blade section integrated together, and this single fan unit is located at a substantially central position in the tilt stand  26 . Alternatively, a plurality of fans may be provided in the tilt stand  26 , or the driving section and the rotating blade section may be separated. The extensible partition member  35  is a laterally elongated, bellowslike member normally folded in the longitudinal direction of the housing  20  and connected between the housing  20  and the tilt stand  26  to fill a gap defined therebetween. That is, the extensible partition member  35  has a front end fixed to a vertical wall of the right-angled bottom portion  20   a  of the housing  20  and a rear end fixed to a front end of the tilt stand  26  in its retracted position. In the retracted position of the tilt stand  26 , the partition member  35  is folded in the gap between the vertical wall of the bottom portion  20   a  of the housing  20  and the front end of the tilt stand  26 .  
         [0023]    In the raised position of the tilt stand  26  as shown in FIG. 6, there is defined an optimum ventilation space S by the tilt stand  26 , the partition member  35 , and the housing  20  by the extension of the partition member  35 . The partition member  35  is formed of any extensible material such as plastics. If the partition member  35  is not provided, a larger ventilation space is defined by the tilt stand  26 , the housing  20 , and a desk on which the device is placed in the raised position of the tilt stand  26 , so that heat from the electronic components  32  may be diffused to an extra area of the ventilation space, and accordingly there is a possibility that the heat cannot be enough expelled by the fan  34 . By determining an optimum mounting position of the partition member  35  in consideration of the capacity of the fan  34 , etc., the optimum ventilation space S can be defined. A switch  40  is pivotably mounted on a horizontal shaft  44  supported to the housing  20 . In the retracted position of the tilt stand  26 , the switch  40  is separate from the projection  36  of the tilt stand  26 . In the raised position of the tilt stand  26 , the switch  40  is in contact with the projection  36 . In raising the tilt stand  26 , the projection  36  comes into contact with the switch  40  and rotates the switch  40  about the shaft  44  clockwise as viewed in FIG. 3.  
         [0024]    A spring  42  is wound around the shaft  44  and supported to a lower projection  46  and an upper projection  48  of the switch  40 . The switch  40  has a terminal  50  formed of conductor at an upper position. In the retracted position of the tilt stand  26 , the terminal  50  of the switch  40  is separate from a terminal  58  supported to the housing  20 . In the raised position of the tilt stand  26 , the terminal  50  of the switch  40  is in contact with the terminal  58  of the housing  20 . A wire  52  is connected at its one end to the terminal  50  and connected at the other end to the power supply  60 . On the other hand, a wire  54  is connected at its one end to the terminal  58  and connected at the other end to a clock switching element  62 , and a wire  56  is connected at its one end to the terminal  58  and connected at the other end to the driving section (not shown) of the fan  34 . The power supply  60  functions to supply a supply voltage from a battery (not shown) accommodated in the housing  20  or from an adapter (not shown) for converting a commercial AC voltage into a DC voltage, to the electronic components  32 , the clock switching element  62 , and the driving section of the fan  34 . The clock switching element  62  receives a high-speed clock signal CLK 1  having a frequency of 100 MHz, for example, and a low-speed clock signal CLK 2  having a frequency of 50 MHz, for example from a clock generating circuit (not shown), and further receives a control signal for a supply voltage or a ground potential from the switch  40 . When the potential of the control signal is equal to the supply voltage, the clock switching element  62  supplies the high-speed clock signal CLK 1  to the electronic components  32 , whereas when the potential of the control signal is equal to the ground potential, the clock switching element  62  supplies the low-speed clock signal CLK 2  to the electronic components  32 .  
         [0025]    [0025]FIGS. 5A, 5B, and  6  illustrate the operation of the information processing device shown in FIG. 2. The operation of the information processing device shown in FIG. 2 will now be described with reference to these figures.  
         [0026]    (a) Operation in the raised position of the tilt stand  26 :  
         [0027]    In the case of using the device in the raised position of the tilt stand  26 , the adapter is used in general. In this case, a commercial AC voltage is converted into a DC voltage by the adapter, and the DC voltage is supplied as a supply voltage from the power supply  60  to the electronic components  32 , the clock switching element  62 , and the fan  34 . The tilt stand  26  is rotated about the shaft  28  counterclockwise as viewed in FIG. 3 by a user until the tilt stand  26  abuts against the stopper  38  as shown in FIG. 6. Accordingly, the tilt stand  26  is supported in a substantially vertical position by the stopper  38  and placed on a desk  70  or the like. At the same time, the folded partition member  35  is extended by the rotation of the tilt stand  26  as shown in FIG. 6, thereby defining the optimum ventilation space S among the partition member  35 , the tilt stand  26 , and the right-angled bottom portion  20   a  of the housing  20 .  
         [0028]    Further, the projection  36  of the tilt stand  26  rotates counterclockwise and comes into contact with the lower projection  46  of the switch  40  to press the switch  40  and rotate it about the shaft  44  clockwise as viewed in FIG. 6 against the biasing force of the spring  42 . As a result, the terminal  50  of the switch  40  comes into contact with the terminal  58  as shown in FIGS. 5A and 6, thereby supplying the supply voltage from the power supply  60  to the terminal  58 . Because the terminal  58  is connected through the wire  54  to a terminal for inputting the control signal for the clock switching element  62  and also connected through the wire  56  to the driving section of the fan  34 , the potential of the control signal for the clock switching element  62  becomes equal to the supply voltage from the power supply  60 , and the clock switching element  62  supplies the high-speed clock signal CLK 1  to the electronic components  32 . Accordingly, the CPU is operated by the high-speed clock signal CLK 1 . Further, the supply voltage is supplied to the driving section of the fan  34  to operate the fan  34 . On the other hand, the heat generated from the electronic components  32  including the CPU operated by the high-speed clock signal CLK 1  is relieved through the ventilation holes  31  of the bottom portion  20 a of the housing  20  into the ventilation space S. The heat in the ventilation space S is next expelled through the ventilation holes  27  of the tilt stand  26  to the outside of the device by the operation of the fan  34 , thereby cooling the electronic components  32 . The ventilation space S is optimally formed, and the CPU having a higher heating value in the electronic components  32  is located near the ventilation holes  31 . Accordingly, the heat generated from the electronic components  32  can be efficiently relieved to the ventilation space S.  
         [0029]    (b) Operation in the retracted position of the tilt stand  26 :  
         [0030]    In the case of using the device in the retracted position of the tilt stand  26 , the battery is often used as a power source without using the adapter, and the device is used on the user&#39;s lap, for example. In retracting the tilt stand  26  from the raised position shown in FIG. 6, the tilt stand  26  is rotated clockwise as viewed in FIG. 6 by the biasing force of the spring  42 . As a result, the projection  36  of the tilt stand  26  is separated from the switch  40 , and the terminal  50  of the switch  40  is also separated from the terminal  58  as shown in FIGS. 3 and 5B. Accordingly, the potentials at the wire  54  and the terminal  58  become equal to a ground potential, so that the potential of the control signal for the clock switching element  62  becomes equal to a ground potential, and the clock switching element  62  supplies the low-speed clock signal CLK 2  to the electronic components  32 .  
         [0031]    As a result, the CPU is operated at a low speed, thereby suppressing current consumption and heat generation. Accordingly, although the device is used on the user&#39;s lap, possible low-temperature burn to the user due to the heat expelled from the device can be suppressed. Further, because the potential at the wire  56  also becomes equal to a ground potential, the fan  34  is not driven, thereby eliminating power consumption of the battery due to the operation of the fan  34 .  
         [0032]    As described above, the fan  34  is provided in the tilt stand  26  having the ventilation holes  27 . In the raised position of the tilt stand  26 , the CPU is operated at a high speed, and the fan  34  is driven to forcibly expel the heat from the CPU through the sufficient ventilation space S to the outside of the device, thereby efficiently cooling the CPU. On the other hand, in the retracted position of the tilt stand  26 , the CPU is operated at a low speed to suppress heat generation from the CPU, thereby suppressing the occurrence of low-temperature burn in the case of using the device on the user&#39;s lap.  
         [0033]    According to the present invention, a sufficient ventilation space can be defined in the raised position of the tilt stand  26 , and the heat generated from the electronic components can be efficiently expelled through the ventilation space by the fan built in the tilt stand.