Abstract:
A heat-dissipation method comprises providing a heat-transfer module and a heat-dissipation module, wherein the heat-transfer module is disposed in a portable electronic device, and the heat-dissipation module is disposed in a battery charger. The heat-dissipation module then contacts the heat-transfer module to remove heat from the electronic device via conduction. Finally, the heat-dissipation module dissipates heat via conduction or convection.

Description:
BACKGROUND  
       [0001]     The invention relates to a portable electronic device and a heat-dissipation method thereof, and more particularly to a heat-dissipation method dissipating heat via a battery charger.  
         [0002]     When a portable electronic device (for example, a personal digital assistant or a cell phone) is charged, heat produced by chips is transferred to the battery, light emitting elements or other electronic elements therein via circuit board, and raises the temperature thereof. This can damage electronic elements and shorten product lifespan. Battery charging generates a high temperature that may cause a battery (for example, lithium battery) to explode. Specifically, an inner temperature of the portable electronic device is raised when the device engages in wireless network communication or other operation with high energy consumption in charging.  
       SUMMARY  
       [0003]     An embodiment of a heat-dissipation method comprises providing a heat-transfer module and a heat-dissipation module, wherein the heat-transfer module is disposed in a portable electronic device, and the heat-dissipation module is disposed in a battery charger. The heat-dissipation module then contacts the heat-transfer module to remove heat from the electronic device via conduction. Finally, the heat-dissipation module dissipates heat via conduction or convection.  
         [0004]     The invention lowers an inner temperature of the portable electronic device, extends the lifespan thereof, and prevents an explosion of the battery. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0005]     The invention will be more fully understood from the following detailed description and the accompanying drawings, given by the way of illustration only and thus not intended to limit the invention.  
         [0006]      FIG. 1  shows a portable electronic device placed in a battery charger;  
         [0007]      FIG. 2   a  shows inner structures of a portable electronic device and a battery charger of a first embodiment of the invention;  
         [0008]      FIG. 2   b  shows an inner structure of the portable electronic device of the first embodiment of the invention;  
         [0009]      FIG. 2   c  shows an inner structure of the battery charger of the first embodiment of the invention;  
         [0010]      FIG. 3  shows heat dissipated by the first embodiment of the invention;  
         [0011]      FIG. 4   a  is a sectional view of the portable electronic device and the battery charger along direction A-A of  FIG. 2   a;    
         [0012]      FIG. 4   b  shows a heat-transfer module and nearby structure of the first embodiment of the invention;  
         [0013]      FIG. 4   c  shows the heat-transfer module abutting a heat-transfer element of the first embodiment of the invention;  
         [0014]      FIG. 4   d  shows a modified example of the first embodiment of the invention;  
         [0015]      FIG. 5   a  shows an inner structure of a portable electronic device of the second embodiment of the invention;  
         [0016]      FIG. 5   b  shows a heat-transfer module and nearby structure of the second embodiment of the invention;  
         [0017]      FIG. 5   c  shows the portable electronic device of the second embodiment placed in a battery charger;  
         [0018]      FIG. 5   d  shows the heat-transfer module abutting a heat-transfer element of the second embodiment of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0019]     With reference to  FIG. 1 , a heat-dissipation module in the battery charger  200  dissipates heat from the portable electronic device  100 , reduces the temperature therein, extends lifespan thereof, and prevents explosion of the battery when a portable electronic device (personal digital assistant)  100  is placed in a battery charger  200 .  
       First Embodiment  
       [0020]      FIG. 2   a  shows inner structures of a portable electronic device  100  and a battery charger  200  of a first embodiment of the invention. In the following, the portable electronic device  100  and the battery charger  200  are described respectively. As shown in  FIG. 2   b , the portable electronic device  100  comprises a housing  110 , a first circuit board  120  and a heat-transfer module  130 . The housing  110  comprises a first opening  111  and a third opening  113 . The first circuit board  120  and the heat-transfer module  130  are disposed in the housing  110 . The heat-transfer module  130  is disposed on an isolation region (a region with no circuit formed thereon) on the first circuit board  120  corresponding to the first opening  111 . The first circuit board  120  comprises an universal serial bus (USB) port  121  corresponding to the third opening  113 .  
         [0021]     As shown in  FIG. 2   c , the battery charger  200  comprises a heat-dissipation module  210 , a chamber  220 , a second circuit board  232 , an universal serial bus (USB) plug  231 , a commutator  310  and a data line  320 . The heat-dissipation module  210  and the second circuit board  232  are disposed in the chamber  220 . The second circuit board  232  and the USB plug  231  compose a charger module. The commutator  310  and the data line  320  are coupled to the second circuit board  232 . The commutator  310  supplies charging power. The data line  320  transmits data signals. The USB plug  231  is coupled to the second circuit board  232 . The charging power and the data signals are transferred to the portable electronic device  100  via the USB plug  231 . The heat-dissipation module  210  comprises a heat-transfer element  211 , a heat-dissipation element  212  and a heat pipe  213 . The heat pipe  213  comprises a vaporizing end and a condensing end. The heat-transfer element  211  contacts the vaporizing end, and the heat-dissipation end  212  contacts the condensing end. The heat-transfer element  211  is L-shaped and comprises copper. The heat-dissipation element  212  comprises copper.  
         [0022]     In a modified example, the commutator  310  can also be eliminated from the battery charger  200 , and the battery charger  200  receives electric power and data signals through the data line  320 .  
         [0023]     With reference to  FIG. 3 , the USB plug  231  is connected to the USB port for supplying electric power when the portable electronic device  100  is disposed on the battery charger  200 . As shown by the arrow in  FIG. 3 , heat of the first circuit board  120  passes the heat-transfer module  130 , the heat-transfer element  211  and the heat pipe  213 , and is transferred to the heat-dissipation element  212 . The inner temperature of the portable electronic device  100  is thus reduced.  
         [0024]      FIG. 4   a  is a sectional view of the portable electronic device  100  and the battery charger  200  along the direction A-A of  FIG. 2   a , wherein the heat-transfer element  211  is inserted into the housing  110  through the first opening. The heat-transfer module  130  abuts the heat-transfer element  211  by the weight of the portable electronic device  100 , and transfers heat via conduction.  
         [0025]      FIG. 4   b  shows the heat-transfer module  130  and nearby structures. The heat-transfer module  130  comprises a metal sheet  133  and a housing  134 . The metal sheet  133  is partially disposed in the housing  134 . The metal sheet  133  is made of copper, and comprises a first portion  131  and a second portion  132 . The second portion  132  is a U-shaped elastic structure. In a first position, the second portion  132  does not contact the heat-transfer element. The first portion  131  contacts the first circuit  120 , transferring heat therefrom.  
         [0026]     As shown in  FIG. 4   c , when the portable electronic device is placed on the battery charger, the heat-transfer element  211  is inserted into the housing  110  through the first opening  111  in a first direction y (an insertion direction of the first opening  111 ). The second portion  132  is moved to a second position in the first direction y by the weight of the portable electronic device when the second portion  132  abuts the heat-transfer element  211 . The second portion  132  sufficiently contacts the heat-transfer element  211 , and heat of the first circuit board  120  passes the first portion  131  and the second portion  132  to the heat-transfer element  211  via conduction.  
         [0027]     As show in  FIG. 4   a , a second opening  241  is formed at the bottom of the chamber  220 . The heat-dissipation element  212  is disposed in the second opening  241 . The heat-dissipation element  212  thus contacts a supporting surface (for example, table surface) for dissipating heat via conduction. As shown in  FIG. 4   d , a protrusion structure  242  can be further disposed on the bottom of the battery charger  200 . Thus, the heat-dissipation  212  contacts external air, and dissipates heat via convection. The heat-dissipation element  212  increases the weight of the battery charger  200  and improves stability thereof.  
       Second Embodiment  
       [0028]      FIG. 5   a  shows a second embodiment of the invention, which differs from the first embodiment in the heat-transfer module  130 ′.  FIG. 5   b  shows the heat-transfer module  130  and nearby structures. In the second embodiment, the first circuit board  120  nears a back side of the portable electronic device. The heat-transfer module  130 ′ comprises a metal sheet  133 ′ and a housing  134 ′. The metal sheet  133 ′ is partially disposed in the housing  134 ′. The metal sheet is of copper, and comprises a first portion  131 ′ and a second portion  132 ′. The second portion  132 ′ is an elastic structure. When the second portion  132 ′ is in a first position, it does not contact the heat-transfer element. The first position  131 ′ contacts the first circuit board  120 ′ and transmits heat therefrom.  
         [0029]     With reference to  FIG. 5   c , when the portable electronic device  100  is placed in the battery charger  200 , the second portion  132 ′ abuts the heat-transfer element  211  via elastic force. With reference to  FIG. 5   d , the heat-transfer element  211  is inserted into the housing  110  through the first opening  111  in a first direction y (an insertion direction of the first opening  111 ), and the second portion  132 ′ is moved to a second position in a second direction x. The second direction x is perpendicular to the first direction y. Heat is transferred from the first circuit board  120 , passing the first portion  131 ′ and the second portion  132 ′ to the heat-transfer element  211  via conduction.  
         [0030]     The invention lowers an inner temperature of the portable electronic device, extends lifespan thereof, and prevents explosion of the battery.  
         [0031]     While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation to encompass all such modifications and similar arrangements.