Patent Publication Number: US-10314198-B2

Title: Air-cooling heat dissipation device and system

Description:
FIELD OF THE INVENTION 
     The present invention relates to an air-cooling heat dissipation device and system. More particularly, it relates to an air-cooling heat dissipation device using an air pump to produce an air flow to remove heat and plural devices may be incorporated into a system. 
     BACKGROUND OF THE INVENTION 
     With increasing development of science and technology, the trends of designing electronic devices such as portable computers, tablet computers, industrial computers, portable communication devices or video players are designed toward minimization, easy portability and high performance. Generally, the limited space inside the electronic device is equipped with various high-integration or high-power electronic components for increasing the computing speed and the function of the electronic device, thus generating a great deal of heat during operations. Consequently, the temperature inside the device is increased and high temperature is harmful to the components. Since the electronic device is usually designed as possible as in slim, flat and succinct appearance, it has insufficient inner space for dissipating the waste heat. In case that the heat is not effectively dissipated away, the electronic components of the electronic device are adversely affected by the heat and the high temperature may result in the interference of operation or damaged of the device. 
     Generally, there are two types of the heat-dissipating mechanisms used in the electronic device to solve such problem, which are known as active heat-dissipating mechanism and passive heat-dissipating mechanism. The active heat-dissipating mechanism is usually presented as an axial fan or a blower, disposed within the electronic device, which can generate an air flow through the space inside the electronic device that dissipating the waste heat. However, the axial fan and the blower are noisy during operation. In addition, they are bulky and have short life span and not suitable to be used in the small-sized, portable electronic device. 
     On the other hand, electronic components are generally fixed on a printed circuit board (PCB) by means of surface mount technology (SMT) or selective soldering technology. The electronic components would readily come off from the PCB board due to exposure of high temperature. Moreover, most electronic components would be damaged by high temperature. In other words, high temperature not only impairs the stability of performance of the electronic components, but also shortens the life span of the electronic components. 
       FIG. 1  is a schematic view illustrating a conventional heat-dissipating mechanism as the passive heat-dissipating mechanism. As shown in  FIG. 1 , the conventional heat-dissipating mechanism  1  provides a thermal conduction plate  12  attaching on a surface of an electronic component  11  by thermal adhesive  13 . Therefore, the thermal adhesive  13  and the thermal conduction plate  12  form a thermal conduction path by which the waste heat generated by the electronic component  11  can be conducted away and then dissipated by convection. However, the heat dissipating efficiency of the conventional heat-dissipating mechanism  1  is usually insufficient, and thus the applications of the conventional heat-dissipating mechanism  1  are limited. 
     Therefore, there is a need of providing an air-cooling heat dissipation device and system with improved performance in order to overcome the drawbacks of the conventional technologies. 
     SUMMARY OF THE INVENTION 
     An object of the present invention provides an air-cooling heat dissipation device and system for an electronic device to remove heat generated by electronic components thereof by means of lateral heat convection. The use of the air-cooling heat dissipation device can increase the heat dissipating efficiency and prevent generating unacceptable noise. Consequently, the performance of the electronic components of the electronic device is stabilized and the life spans of the electronic components are extended. Moreover, since it is not necessary to attach a heat sink on the electronic component, the overall thickness of the electronic device is reduced. 
     Another object of the present invention provides an air-cooling heat dissipation device and an air-cooling heat dissipation system with a temperature controlling function. The operations of an air pump are controlled according to the temperature changes of the electronic components of the electronic device. Consequently, the life span of the air pump is extended. 
     In accordance with an aspect of the present invention, an air-cooling heat dissipation device is located near an electronic component for removing heat therefrom. The air-cooling heat dissipation device includes a base and an air pump. The base includes a top surface, a bottom surface, two lateral walls, a guiding chamber, an introduction opening and plural discharge grooves. The lateral walls are connected between the top surface and the bottom surface. The introduction opening is formed in the top surface. The guiding chamber runs through the bottom surface and is in communication with the introduction opening. The pluraldischarge grooves are formed in one of the lateral wall s and in communication with the guiding chamber. The plural discharge grooves are oriented toward the electronic component. The air pump is disposed on the top surface of the base and sealing the edge of the introduction opening. When the air pump is enabled, an ambient air is driven by the air pump and introduced into the guiding chamber through the introduction opening and then discharged through the plural discharge grooves such that a lateral air flow is generated and passes over the electronic component to remove the heat from the electronic component. 
     In accordance with another aspect of the present invention, an air-cooling heat dissipation system is provided. The air-cooling heat dissipation system includes plural air-cooling heat dissipation devices, and the air-cooling heat dissipation devices are located near the electronic component. 
     The above contents of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view illustrating a conventional heat-dissipating mechanism; 
         FIG. 2A  is a schematic perspective view illustrating the structure of an air-cooling heat dissipation device according to a first embodiment of the present invention; 
         FIG. 2B  is a schematic cross-sectional view illustrating the air-cooling heat dissipation device of  FIG. 2A  and taken along the line AA; 
         FIG. 3A  is a schematic perspective view illustrating a base of the air-cooling heat dissipation device as shown in  FIG. 2A ; 
         FIG. 3B  is a schematic perspective view illustrating the base of  FIG. 3A  and taken along another viewpoint; 
         FIG. 4  schematically illustrates the architecture of an air-cooling heat dissipation system according to an embodiment of the present invention; 
         FIG. 5A  is a schematic exploded view illustrating an air pump used in the air-cooling heat dissipation device of the present invention; 
         FIG. 5B  is a schematic exploded view illustrating the air pump of  FIG. 5A  and taken along another viewpoint; 
         FIG. 6  is a schematic cross-sectional view illustrating a piezoelectric actuator of the air pump as shown in  FIGS. 5A and 5B ; 
         FIG. 7  is a schematic cross-sectional view illustrating the air pump as shown in  FIGS. 5A and 5B ; 
         FIGS. 8A to 8E  schematically illustrate the actions of the air pump of  FIGS. 5A and 5B ; and 
         FIG. 9  is a schematic cross-sectional view illustrating an air-cooling heat dissipation device according to a second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed. 
       FIG. 2A  is a schematic perspective view illustrating the structure of an air-cooling heat dissipation device according to a first embodiment of the present invention.  FIG. 2B  is a schematic cross-sectional view illustrating the air-cooling heat dissipation device of  FIG. 2A  and taken along the line AA.  FIG. 3A  is a schematic perspective view illustrating a base of the air-cooling heat dissipation device as shown in  FIG. 2A .  FIG. 3B  is a schematic perspective view illustrating the base of  FIG. 3A  and taken along another viewpoint. 
     Please refer to  FIGS. 2A, 2B, 3A and 3B . The air-cooling heat dissipation device  2  is applied to an electronic device (not shown) to remove the heat generated by an electronic component  3  of the electronic device. An example of the electronic device includes but is not limited to a portable computer, tablet computer, an industrial computer, a portable communication device or video player. The air-cooling heat dissipation device  2  comprises a base  20  and an air pump  22 . The base  20  comprises a top surface  20   a , a bottom surface  20   b , a guiding chamber  200 , an introduction opening  201 , plural discharge grooves  203 , and two lateral walls which are indicated as a first lateral wall  204   a  and a second lateral wall  204   b.    
     The top surface  20   a  and the bottom surface  20   b  are opposite to each other, while the first lateral wall  204   a  and the second lateral wall  204   b  are connected between the top surface  20   a  and the bottom surface  20   b . The guiding chamber  200  is enclosed by the top surface  20   a  and the lateral walls, and runs through the bottom surface  20   b . The introduction opening  201  is formed in the top surface  20   a  and is in communication with the guiding chamber  200 . 
     In some embodiments, the air-cooling heat dissipation device  2  may comprise a receiving part  202 , which is a recess concavely formed in the top surface  20   a  of the base  20  and arranged around the introduction opening  201 . The receiving part  202  is for the air pump  22  to be assembled with that can position the air pump  22  in a lower level. In some other embodiments, the base  20  may not be equipped with the receiving part  202 . As so, the air pump  22  is assembled with the top surface  20   a  of the base  20  and sealing the edge of the introduction opening  201 , and the efficiency of heat dissipation of the device is not affected. 
     The plural discharge grooves  203  are formed in any one of the lateral walls, which is exemplified by the second lateral wall  204   b  hereinafter. The discharge grooves  203  provide access between the guiding chamber  200  and the exterior surroundings. The air pump  22  is assembled with the receiving part  202  of the base  20  and sealing the edge of the introduction opening  201 . When the air pump  22  is enabled, the ambient air is driven by the air pump  22  and introduced into the guiding chamber  200  through the introduction opening  201 , and quickly discharged through the plural discharge grooves  203 . Consequently, a lateral air flow  205  is generated and passes over the electronic component  3  in which heat exchange occurs. 
     In some embodiments, the air-cooling heat dissipation device  2  further comprises a supporting substrate  4 , and the electronic component  3  is disposed on the supporting substrate  4 . Preferably but not exclusively, the supporting substrate  4  is a printed circuit board. A portion of the supporting substrate  4  is connected to the bottom surface  20   b  of the base  20  to close the bottom side of the guiding chamber  200 . That is, the base  20  is fixed on the supporting substrate  4  and located near the electronic component  3 . In the meantime, plural discharge openings  203   a  of the plural discharge grooves  203  are oriented toward the electronic component  3 . 
     In some embodiments, the air pump  22  is a piezoelectric air pump. The air pump  22  is fixed in the receiving part  202  of the base  20 . Moreover, the air pump  22  is assembled with and sealing the edge of the introduction opening  201 . The base  20  is fixed by attaching the bottom surface  20   b  thereof on the supporting substrate  4 . In other words, a combination of the base  20  and the air pump  22  covers and joins to a portion of the supporting substrate  4 , while an electronic component  3  is disposed on another portion of the supporting substrate  4  and is located nearby. Meanwhile, the discharge grooves  203  are oriented toward the electronic component  3 . Since the introduction opening  201  is sealed by the air pump  22  and the bottom side of the guiding chamber  200  is enclosed by the supporting substrate  4 , an enclosed passage is defined by the introduction opening  201 , the guiding chamber  200  and the plural discharge grooves  203  collaboratively. The enclosed passage can guide and collect the introduced air to become a lateral air flow  205  that removing the heat from the electronic component  3 , which enhances the heat dissipating efficiency. It is noted that numerous modifications and alterations may be made while retaining the teachings of the invention. The type of the passage may be varied according to the practical requirement, which means the passage is not limited to the enclosed type. 
     The air pump  22  is operable to drive the external ambient air to be continuously introduced into the guiding chamber  200  through the introduction opening  201  and quickly discharged through the discharge grooves  203 . Consequently, a lateral air flow  205  is generated. In duration of the operation of the air pump, the lateral air flow  205  keeps passing over the electronic component  3  and causes heat convection around the electronic component  3 , which maintains transferring waste heat generated by the electronic component  3  away. Thus, high temperature of or around the electronic component  3  is prevented, and the life span and stability of performance of the electronic component  3  are increased. Moreover, the overall thickness of the air-cooling heat dissipation device is reduced. 
       FIG. 4  schematically illustrates the architecture of an air-cooling heat dissipation system according to an embodiment of the present invention. As shown in  FIG. 4 , the air-cooling heat dissipation system  5  comprises plural air-cooling heat dissipation devices. For succinctness, only two air-cooling heat dissipation devices  2 ′ and  2 ″ are shown. The two air-cooling heat dissipation devices  2 ′ and  2 ″ are used to remove the heat from an electronic component  3 . Components corresponding to those of the air-cooling heat dissipation device  2  of  FIG. 2B  are designated by identical numeral references, and detailed descriptions thereof are omitted. In this embodiment, the two air-cooling heat dissipation devices  2 ′ and  2 ″ of the air-cooling heat dissipation system  5  are disposed on the supporting substrate  4  and respectively located by two opposite sides of the electronic component  3 . Moreover, the discharge grooves  203  of the bases  20  of the two air-cooling heat dissipation devices  2 ′ and  2 ″ are oriented toward the two opposite sides of the electronic component  3  respectively. When the air pumps  22  of the two air-cooling heat dissipation devices  2 ′ and  2 ″ are enabled, the ambient air is introduced into the guiding chambers  200  through the introduction openings  201  and quickly discharged through the discharge grooves  203  of the air-cooling heat dissipation devices  2 ′ and  2 ″. Consequently, two lateral air flows  205  in reverse directions are generated and both pass over the electronic component  3 , thus causing convection around the electronic component  3  that removing heat therefrom. As a result, high temperature of or around the electronic component  3  is prevented, and the life span and stability of performance of the electronic component  3  are increased. It is noted that the number of the air-cooling heat dissipation devices of the air-cooling heat dissipation system may be varied according to the practical requirements. 
       FIG. 5A  is a schematic exploded view illustrating an air pump used in the air-cooling heat dissipation device according to an embodiment of the present invention.  FIG. 5B  is a schematic exploded view illustrating the air pump of  FIG. 5A  and taken along another viewpoint.  FIG. 6  is a schematic cross-sectional view illustrating a piezoelectric actuator of the air pump as shown in  FIGS. 5A and 5B .  FIG. 7  is a schematic cross-sectional view illustrating the air pump as shown in  FIGS. 5A and 5B . Please refer to  FIGS. 5A, 5B, 6 and 7 . According to an embodiment of the present invention, the air pump  22  is a piezoelectric air pump, comprising a gas inlet plate  221 , a resonance plate  222 , a piezoelectric actuator  223 , a first insulation plate  2241 , a conducting plate  225  and a second insulation plate  2242 , which are stacked on each other sequentially. The piezoelectric actuator  223  is aligned with the resonance plate  222 . After the above components are combined together, the cross-sectional view of the resulting structure of the air pump  22  is shown in  FIG. 7 . 
     The gas inlet plate  221  comprises at least one inlet  221   a . Preferably but not exclusively, the gas inlet plate  221  comprises four inlets  221   a . The inlets  221   a  run through the gas inlet plate  221 . In response to the action of the atmospheric pressure, the air is introduced into the air pump  22  through the inlets  221   a . Moreover, at least one convergence channel  221   b  is formed on a first surface of the gas inlet plate  221 , and is in communication with the at least one inlet  221   a  on a second surface of the gas inlet plate  22 . Moreover, a central cavity  221   c  is located at the intersection of the four convergence channels  221   b . The central cavity  221   c  is in communication with the at least one convergence channel  221   b , such that the gas entered by the inlets  221   a  would be introduced into the at least one convergence channel  221   b  and is guided to the central cavity  221   c . Consequently, the air can be transferred by the air pump  22 . In this embodiment, the at least one inlet  221   a , the at least one convergence channel  221   b  and the central cavity  221   c  of the gas inlet plate  221  are integrally formed. The central cavity  221   c  is a convergence chamber for temporarily storing the air. Preferably but not exclusively, the gas inlet plate  221  is made of stainless steel. In some embodiments, the depth of the convergence chamber defined by the central cavity  221   c  is equal to the depth of the at least one convergence channel  221   b . The resonance plate  222  is made of a flexible material, which is preferably but not exclusively copper. The resonance plate  222  further has a central aperture  2220  corresponding to the central cavity  221   c  of the gas inlet plate  221  that providing the gas for flowing through. 
     The piezoelectric actuator  223  comprises a suspension plate  2231 , an outer frame  2232 , at least one bracket  2233  and a piezoelectric plate  2234 . The piezoelectric plate  2234  is attached on a first surface  2231   c  of the suspension plate  2231 . In response to an applied voltage, the piezoelectric plate  2234  would be subjected to a deformation. When the piezoelectric plate  2233  is subjected to the deformation, the suspension plate  2231  is subjected to a curvy vibration. The at least one bracket  2233  is connected between the suspension plate  2231  and the outer frame  2232 , while the two ends of the bracket  2233  are connected with the outer frame  2232  and the suspension plate  2231  respectively that the bracket  2233  can elastically support the suspension plate  2231 . At least one vacant space  2235  is formed between the bracket  2233 , the suspension plate  2231  and the outer frame  2232 . The at least one vacant space  2235  is in communication with the introduction opening  201  for allowing the air to go through. The type of the suspension plate  2231  and the outer frame  2232 , and the type and the number of the at least one bracket  2233  may be varied according to the practical requirements. The outer frame  2232  is arranged around the suspension plate  2231 . Moreover, a conducting pin  2232   c  is protruding outwardly from the outer frame  2232  so as to be electrically connected with an external circuit (not shown). 
     As shown in  FIG. 6 , the suspension plate  2231  has a bulge  2231   a  that makes the suspension plate  2231  a stepped structure. The bulge  2231   a  is formed on a second surface  2231   b  of the suspension plate  2231 . The bulge  2231   b  may be a circular convex structure. A top surface of the bulge  2231   a  of the suspension plate  2231  is coplanar with a second surface  2232   a  of the outer frame  2232 , while the second surface  2231   b  of the suspension plate  2231  is coplanar with a second surface  2233   a  of the bracket  2233 . Moreover, there is a drop of specified amount from the bulge  2231   a  of the suspension plate  2231  (or the second surface  2232   a  of the outer frame  2232 ) to the second surface  2231   b  of the suspension plate  2231  (or the second surface  2233   a  of the bracket  2233 ). A first surface  2231   c  of the suspension plate  2231 , a first surface  2232   b  of the outer frame  2232  and a first surface  2233   b  of the bracket  2233  are coplanar with each other. The piezoelectric plate  2234  is attached on the first surface  2231   c  of the suspension plate  2231 . The suspension plate  2231  may be a square plate structure with two flat surfaces but the type of the suspension plate  2231  may be varied according to the practical requirements. In this embodiment, the suspension plate  2231 , the at least bracket  2233  and the outer frame  2232  are integrally formed and produced by using a metal plate (e.g., a stainless steel plate). In an embodiment, the length of the piezoelectric plate  2234  is smaller than the length of the suspension plate  2231 . In another embodiment, the length of the piezoelectric plate  2234  is equal to the length of the suspension plate  2231 . Similarly, the piezoelectric plate  2234  is a square plate structure corresponding to the suspension plate  2231 . 
     In the air pump  22 , the first insulation plate  2241 , the conducting plate  225  and the second insulation plate  2242  are stacked on each other sequentially and located under the piezoelectric actuator  223 . The profiles of the first insulation plate  2241 , the conducting plate  225  and the second insulation plate  2242  substantially match the profile of the outer frame  2232  of the piezoelectric actuator  223 . The first insulation plate  2241  and the second insulation plate  2242  are made of an insulating material (e.g. a plastic material) for providing insulating efficacy. The conducting plate  225  is made of an electrically conductive material (e.g. a metallic material) for providing electrically conducting efficacy. Moreover, the conducting plate  225  has a conducting pin  225   a  so as to be electrically connected with an external circuit (not shown). 
     In an embodiment, the gas inlet plate  221 , the resonance plate  222 , the piezoelectric actuator  223 , the first insulation plate  2241 , the conducting plate  225  and the second insulation plate  2242  of the air pump  22  are stacked on each other sequentially. Moreover, there is a gap h between the resonance plate  222  and the outer frame  2232  of the piezoelectric actuator  223 , which is formed and maintained by a filler (e.g. a conductive adhesive) inserted therein in this embodiment. The gap h ensures the proper distance between the bulge  2231   a  of the suspension plate  2231  and the resonance plate  222 , so that the contact interference is reduced and the generated noise is largely reduced. In some embodiments, the height of the outer frame  2232  of the piezoelectric actuator  223  is increased, so that the gap is formed between the resonance plate  222  and the piezoelectric actuator  223 . 
     After the gas inlet plate  221 , the resonance plate  222  and the piezoelectric actuator  223  are combined together, a movable part  222   a  and a fixed part  222   b  of the resonance plate  222  are defined. A convergence chamber for converging the air is defined by the movable part  222   a  of the resonance plate  222  and the gas inlet plate  211  collaboratively. Moreover, a first chamber  220  is formed between the resonance plate  222  and the piezoelectric actuator  223  for temporarily storing the air. Through the central aperture  2220  of the resonance plate  222 , the first chamber  220  is in communication with the central cavity  221   c  of the gas inlet plate  221 . The peripheral regions of the first chamber  220  are in communication with the underlying introduction opening  201  through the vacant space  2235  between the brackets  2233  of the piezoelectric actuator  223 . 
       FIGS. 8A to 8E  schematically illustrate the actions of the air pump of  FIGS. 5A and 5B . Please refer to  FIGS. 7 and 8A to 8E . The actions of the air pump will be described as follows. When the air pump  22  is enabled, the piezoelectric actuator  223  is vibrated along a vertical direction in a reciprocating manner by using the bracket  2233  as the fulcrums. The resonance plate  222  except for the part of it fixed on the gas inlet plate  221  is hereinafter referred as a movable part  222   a , while the rest is referred as a fixed part  222   b . Since the resonance plate  222  is light and thin, the movable part  222   a  vibrates along with the piezoelectric actuator  223  because of the resonance of the piezoelectric actuator  223 . In other words, the movable part  222   a  is reciprocated and subjected to a curvy deformation. When the piezoelectric actuator  223  is vibrated downwardly, the movable part  222   a  of the resonance plate  222  is subjected to the curvy deformation because the movable part  222   a  of the resonance plate  222  is pushed by the air and vibrated in response to the piezoelectric actuator  223 . In response to the downward vibration of the piezoelectric actuator  223 , the air is fed into the at least one inlet  221   a  of the gas inlet plate  221 . Then, the air is transferred to the central cavity  221   c  of the gas inlet plate  221  through the at least one convergence channel  221   b . Then, the air is transferred through the central aperture  2220  of the resonance plate  222  corresponding to the central cavity  221   c , and introduced downwardly into the first chamber  220 . As the piezoelectric actuator  223  is enabled, the resonance of the resonance plate  222  occurs. Consequently, the resonance plate  222  is also vibrated along the vertical direction in the reciprocating manner. 
     As shown in  FIG. 8B , during the vibration of the movable part  222   a  of the resonance plate  222 , the movable part  222   a  moves down till bring contacted with the bulge  2231   a  of the suspension plate  2231 . In the meantime, the volume of the first chamber  220  is shrunken and a middle space which was communicating with the convergence chamber is closed. Under this circumstance, the pressure gradient occurs to push the air in the first chamber  121  moving toward peripheral regions of the first chamber  220  and flowing downwardly through the vacant spaces  2235  of the piezoelectric actuator  223 . 
     Please refer to  FIG. 8C , which illustrates consecutive action following the action in  FIG. 8B . The movable part  222   a  of the resonance plate  222  has returned its original position when, the piezoelectric actuator  223  has ascended at a vibration displacement to an upward position. Consequently, the volume of the first chamber  220  is consecutively shrunken that generating the pressure gradient which makes the air in the first chamber  220  continuously pushed toward peripheral regions. Meanwhile, the air continuously fed into the inlets  221   a  of the gas inlet plate  221  and transferred to the central cavity  221   c.    
     Then, as shown in  FIG. 8D , the resonance plate  222  moves upwardly, which is caused by the resonance of the upward motion of the piezoelectric actuator  223 . Consequently, the air is slowly fed into the inlets  221   a  of the gas inlet plate  221 , and transferred to the central cavity  221   c.    
     As shown in  FIG. 8E , the movable part  222   a  of the resonance plate  222  has returned its original position. When the resonance plate  222  is vibrated along the vertical direction in the reciprocating manner, the gap h between the resonance plate  222  and the piezoelectric actuator  223  providing space for vibration of the resonance plate  222 . That is, the thickness of the gap h affects the amplitude of vibration of the resonance plate  12 . Consequently, a pressure gradient is generated in the fluid channels of the air pump  22  to facilitate the air to flow at a high speed. Moreover, since there is an impedance difference between the feeding direction and the exiting direction, the air can be transmitted from the inlet side to the outlet side. Moreover, even if the outlet side has a gas pressure, the air pump  22  still has the capability of pushing the air to the first guiding chamber  200  while achieving the silent efficacy. 
     The steps of  FIGS. 8A to 8E  are repeatedly done. Consequently, the ambient air is transferred by the air pump  22  from the outside to the inside. 
     As mentioned above, the operation of the air pump  22  can guide the air into the guiding chamber  200  of the base  20  and quickly exhaust the air to the surroundings of the air-cooling heat dissipation device through the discharge grooves  203 . Consequently, the lateral air flow  205  is generated and passes over the electronic component  3 , and the lateral air flow  205  and the ambient air flow result in convection to remove heat from the electronic component  3 . The heated air flow is quickly dissipated away from the electronic component  3  through convection, and thus the heat dissipation of the electronic component  3  is achieved, the performance stability and the life span of the electronic component  3  are increased. 
       FIG. 9  is a schematic cross-sectional view illustrating an air-cooling heat dissipation device according to a second embodiment of the present invention. Components corresponding to those of the first embodiment are designated by identical numeral references, and detailed descriptions thereof are omitted. In comparison with the air-cooling heat dissipation device  2  of  FIG. 2B , the air-cooling heat dissipation device  2   a  of this embodiment further provides a temperature controlling function. According to this embodiment, the air-cooling heat dissipation device  2   a  further comprises a control system  21  composed of a control unit  211  and a temperature sensor  212 . The control unit  211  is electrically connected with the air pump  22  to control the operation of the air pump  22 . The temperature sensor  212  may be directly attached on the electronic component  3  so as to detect the temperature thereof. Alternatively, the temperature sensor  212  may be disposed on the supporting substrate  4  and located near the electronic component  3  so as to detect ambient temperature of the electronic component  3 . The temperature sensor  212  is electrically connected with the control unit  211  to which the detected temperature as a detecting signal is transmitted. After receiving the detecting signal, the control unit  211  determines whether the detected temperature is higher than a pre-determined threshold value. If the detected temperature is determined higher than or equal to the threshold value, the control unit  211  enables the air pump  22 ; oppositely, if the detected temperature is determined lower than the threshold value, the control unit  211  disables the air pump  22 . As so, the air pump  22  operates only when high temperature is detected, thus the life span of the air pump  22  can be prolonged. 
     From the above descriptions, the present invention provides an air-cooling heat dissipation device and a system comprising a plurality of the air-cooling heat dissipation devices. The air-cooling heat dissipation device of the present invention has compact size that are suitable to be applied to a wide variety of portable electronic devices to remove heat generated by electronic components thereof through lateral convection as well as keeping the electronic devices in slim profile. Moreover, the heat is dissipated away more efficiently and the noise during operation is reduced in comparison of the conventional techniques. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.