Abstract:
A portable electronic device, which including a casing, a circuit board, a fan and a heat dissipating device, is disclosed. The circuit board is disposed in the casing and includes at least one electronic component thereon. The fan is disposed in the casing. The heat dissipating device is disposed in the casing and near the side of an air outlet of the fan. Gaps formed between the outer surfaces of the heat dissipating device and the inner surfaces of the casing as air flow channels. The portable electronic device isolates heat conducted to the casing of the portable electronic device via the gaps.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The non-provisional patent application claims priority to U.S. provisional patent application with Ser. No. 61/430,123 filed on Jan. 5, 2011. This and all other extrinsic materials discussed herein are incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The invention relates to a heat dissipating device and, more particularly, to a heat dissipating device of a portable electronic device. 
     2. Related Art 
     Nowadays, computers are important in our life. Currently, a portable electronic device is characterized in light, thin and small, therefore it is widely used. However, the portable electronic device may have problems in heat dissipating. 
     Taking a notebook computer as an example,  FIG. 1  is a top view showing a conventional notebook computer land its heat dissipating fan  12  and the het dissipating fins  13  thereof. The conventional notebook computer  1  dissipates heat of the heat dissipating fins  13  by the heat dissipating fan  12 , disposed in a casing  11  of the conventional notebook computer  1 , and the heat dissipating fan  12  blows hot air out of the casing  11 . In consideration of the small size and the performance, the space for disposing the heat dissipating fan  12  becomes smaller. As a result, the heat dissipating fan  12  only can be disposed at a palm rest area  14 . 
     The heat dissipating fan  12  blows cool air into the heat dissipating fins  13 , the cool air brings heat from the heat dissipating fins  13  and blows out of the casing  11  (shown in arrows). However, the heat dissipating fan  12  blows the hot air from the heat dissipating fins  13  out of the casing  11 , resulting in temperature increasing around the casing. 
     SUMMARY OF THE INVENTION 
     A portable electronic device includes a casing, a circuit board, a fan and a heat dissipating device. The circuit board is disposed in the casing and includes at least one electronic component thereon. The fan is disposed in the casing. The heat dissipating device is disposed in the casing and at a side of an air outlet of the fan. Furthermore, a gap formed between the heat dissipating device and the casing for air flowing. 
     In an embodiment, the heat dissipating device includes an upper surface and a lower surface and the gap formed between the upper surface and the casing and between the lower surface and the casing, respectively. 
     In an embodiment, thickness of the fan is larger than that of the heat dissipating device. 
     In an embodiment, the casing includes at least one opening. 
     In an embodiment, the opening is disposed corresponding to the air outlet of the heat dissipating device. 
     In an embodiment, a space is formed between the opening and the air outlet of the heat dissipating device. 
     In an embodiment, the portable electronic device further includes a keyboard module disposed in the casing, and the fan and the heat dissipating device are disposed adjacent to one side of the keyboard module. 
     In an embodiment, the casing includes a plurality of air inlets formed at the side of the keyboard module opposite to the side of the fan and the heat dissipating device. 
     In an embodiment, a plurality of through holes are formed at the circuit board corresponding to the air inlets. 
     In an embodiment, the shape of the air inlets is the same as the shape of the through holes at the circuit board. 
     In an embodiment, the heat dissipating device includes a plurality of heat dissipating fins and at least one heat pipe. 
     In an embodiment, the electronic component includes one of a central processing unit (CPU), a chipset, a graphic processing unit (GPU), a video graphics array (VGA) and a memory. 
     In an embodiment, the fan further includes an upper cover and a lower cover, the height between the upper cover and the lower cover is larger than the height of the heat dissipating device, the heat dissipating device is disposed between the upper cover and the lower cover, and gaps are formed between the heat dissipating device and the upper cover and between the heat dissipating device and the lower cover, respectively. 
     In an embodiment, the fan further includes an upper cover, a lower cover, an upper block board connected to the upper cover and a lower block board connected to the lower cover, the height between the upper block board and the lower block board is larger than the height of the heat dissipating device, the heat dissipating device is disposed between the upper block board and the lower block board, and a gap formed between the heat dissipating device and the upper block board and formed between the heat dissipating device and the lower block board, respectively. 
     As stated above, in the portable electronic device as disclosed herein, air flow channels are formed via the gaps exist between the outer surface of the heat dissipating device and the inner surface of the casing, between the upper cover and the lower cover of the fan, or between the upper block board and the lower block board of the fan. Thus, the cool air from the fan flows through the air flow channel to isolate the heat of the heat dissipating device from contacting with the casing, so as to prevent heat of the heat dissipating device from conducting to the casing, and the user would not feel uncomfortable when he or she puts the hands at the casing. Furthermore, the cool air from the fan flows through the heat dissipating device, and takes the heat of the heat dissipating device away through the opening of the casing, so as to avoid temperature increasing on the casing or around the casing. 
     These and other features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view showing a conventional portable electronic device with its heat dissipating fan and heat dissipating fins; 
         FIG. 2A  and  FIG. 2B  are respectively a top view and a front view showing the fan and the heat dissipating device of the portable electronic device in an embodiment; 
         FIG. 3  is a front view showing the portable electronic device with its fan and the heat dissipating device in an embodiment; 
         FIG. 4A  is a front view showing the portable electronic device with its fan and the heat dissipating device in an embodiment; 
         FIG. 4B  is a front view showing the portable electronic device with its fan and the heat dissipating device in an embodiment; 
         FIG. 5  is a front view showing the portable electronic device in an embodiment; 
         FIG. 6A  is a sectional diagram showing the portable electronic device in an embodiment; and 
         FIG. 6B  and  FIG. 6C  are side views showing the portable electronic device in an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A portable electronic device is illustrated with relating figures, and the same symbols denote the same components. 
       FIG. 2A  and  FIG. 2B  are top views and front views respectively showing a fan  22  and a heat dissipating device  23  of a portable electronic device  2  in an embodiment. Taking a notebook computer  2  as an example, it includes a casing  21 , a circuit board (not shown), a fan  22  and a heat dissipating device  23 . The circuit board is disposed in the casing  21 , and the electronic components such as a central processing unit (CPU), a chipset, a graphic processing unit (GPU), a video graphics array (VGA) and a memory is selectively disposed on the circuit board as requirement, which is not limited herein. The fan  22  and the heat dissipating device  23  are disposed in the casing  21 , and the heat dissipating device  23  is disposed at a side of an air outlet  221  of the fan  22 . Gaps G 1  and G 2  exist between the outer surface  231 ,  232  of the heat dissipating device  23  and the inner surface  211 ,  212  of the casing  21 , respectively. 
     In  FIG. 2B , the gap G 1  exists between the upper surface  231  of the heat dissipating device  23  and the inner surface  211  of the casing  21 , and the gap G 2  exists between the lower surface  232  of the heat dissipating device  23  and the inner surface  212  of the casing  21 . That is, the gap G 1  forms an upper air flow channel, as indicated by an arrow A 1 , and the gap G 2  forms a lower air flow channel, as indicated by an arrow A 2 . The term “air flow channel” means a channel which air flows through. That is, the fan  22  blows cool air through the air flow channel to isolate the heat of the heat dissipating device  23  from contacting with the casing  21 , and thus the user would not feel uncomfortable when he or she puts the hands at the palm rest area  24  due to the temperature increasing of the casing  21 . 
       FIG. 3  is a front view showing a fan  21  and a heat dissipating device  33  of a notebook computer  3  in an embodiment. Specifically, as showed in  FIG. 2B , the two gaps G 1  and G 2  formed between the outer surface  231 ,  232  of the heat dissipating device  23  and the inner surface  211 ,  212  of the casing  21 , respectively, is not limited herein. As shown in  FIG. 3 , a gap G 3  also may be formed between the upper surface  331  of the heat dissipating device  33  and the inner surface  211  of the casing  21 , which is the upper air flow channel, so as to prevent the heat of the heat dissipating device  33  from conducting to the inner surface  211  of the casing  21  and avoid the temperature increasing of the casing  21 . 
     The heat dissipating device may include a plurality of heat dissipating fins and at least one heat pipe. Moreover, the thickness of the fan  22  may be larger than that of the heat dissipating device, that is, the height of the air outlet  221  of the fan  22  is larger than the height of the heat dissipating device. Thus, the cool air from the fan  22  can flow through the heat dissipating device, the upper air flow channel and the lower air flow channel. 
       FIG. 4A  is a front view showing a fan  42  and a heat dissipating device  23  of a notebook computer  4  in an embodiment. In this embodiment, the fan  42  includes an upper cover  421  and a lower cover  422 , and the height between the upper cover  421  and the lower cover  422  is larger than that of the heat dissipating device  23 . The upper cover  421  and the lower cover  422  cover the upper surface  231  and the lower surface  232  of the heat dissipating device  23 , respectively. That is, the heat dissipating device  23  is disposed between the upper cover  421  and the lower cover  422 . Gaps G 4  and G 5  are formed between the upper surface  231  and the lower surface  232  of the heat dissipating device  23 , and between the upper cover  421  and the lower cover  422 , respectively, to form the upper air flow channel and the lower air flow channel as shown as the arrows A 1  and A 2 . 
       FIG. 4B  is a front view showing a fan  44  and a heat dissipating device  23  of a notebook computer  4  in an embodiment. In this embodiment, the fan includes an upper cover  441 , a lower cover  442 , an upper block board  443  connected to the upper cover  441  and a lower block board  444  connected to the lower cover  442 , and the height between the upper block board  443  and the lower block board  444  is larger than that of the heat dissipating device  23 . The upper block board  443  and the lower block board  444  cover the upper surface  231  and the lower surface  232  of the heat dissipating device  23 , respectively. That is, the heat dissipating device  23  is disposed between the upper block board  443  and the lower block board  444 . Gap G 4  is formed between the upper surface  231  of the heat dissipating device  23  and the upper block board  443  as the upper air flow channel, and G 5  is formed between the outer surface  232  of the heat dissipating device  23  and the lower block board  444  as the lower air flow channel, showed as the arrows A 1  and A 2 . 
       FIG. 5  is a front view showing a portable electronic device in an embodiment. The casing  51  of the notebook computer  5  includes at least one opening  511  corresponding to the air outlet  233  of the heat dissipating device  23 , and thus the hot air from the heat dissipating device  23  may be blown out through the air outlet  233  of the heat dissipating device  23  and the opening  511 . The opening  511  may be a hole or a slot, which is not limited herein. The shape of the hole or the slot can be adjusted according to requirements, which is not limited herein. 
     Moreover, a space S forms between the opening  511  and the air outlet  233  of the heat dissipating device  23 . In the space, cool air from the upper surface  231  (the upper air flow channel) and the lower surface  232  (the lower air flow channel) of the heat dissipating device  23  blows through the heat dissipating device  23 , and takes the heat of the heat dissipating device  23  away through the opening  511  of the casing  51  to decrease the temperature of the dissipated hot air. 
       FIG. 6A ,  FIG. 6B  and  FIG. 6C  are sectional diagrams showing a portable electronic device in an embodiment. Taking the notebook computer  6  as an example, it further includes a keyboard module  65  disposed in the casing  61 , and the fan  22  and the heat dissipating device (not shown) are disposed adjacent to a side of the keyboard module  65 . Furthermore, the casing  61  may include a plurality of air inlets  66  formed at a side of the keyboard module  65  opposite to the fan  22  and the heat dissipating device  23 . 
     As shown in  FIG. 6B , a plurality of through holes  671  are formed at the circuit board  67  corresponding to the air inlets  66 , and thus external air can flow through the air inlets  66 , the through holes  671  of the circuit board  67  and at least one electronic component  672  at the circuit board  67  to dissipate heat of the electronic component  672 . Moreover, the air inlets  66  may not correspond to the through hole  671 , as shown in  FIG. 6C . 
     In an embodiment, the shape and the size of the air inlets  66  and the through holes  671  of the circuit board  67  may be the same or not, respectively. 
     Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, the disclosure is not for limiting the scope. Persons having ordinary skill in the art may make various modifications and changes without departing from the scope. Therefore, the scope of the appended claims should not be limited to the description of the preferred embodiments described above.