Patent Publication Number: US-2011073159-A1

Title: Heat Dissipating Device and Module Using Same

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a heat dissipating device and a module using the same. 
     2. Description of the Prior Art 
     It is a global trend of using light-emitting diodes (LEDs) in replacement of traditional light sources in illumination apparatuses. The extensive use of LEDs as a light source in illumination apparatuses, however, has not prevailed to date due to lack of methods and apparatuses that are capable of effectively reducing the working temperature of LEDs to thereby suppress the decay in light emission therefrom and enhance the brightness thereof. 
     In view of the above, the inventors have devised a heat dissipating device, as well as a module using the same, to fulfill the need in this respect. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the invention is to provide a heat dissipating device and a module using the same. 
     In order to achieve this object, a heat dissipating device adapted for use in combination with a module having a mounting board according to a technical feature of the invention is provided, which comprises a metallic heat-dissipating member including a body having a upper surface and a lower surface and a plurality of spaced-apart heat dissipating fins extending upwardly from the upper surface of the body. The body is formed at its central portion with a through hole that communicates the upper surface with the lower surface. The through hole is adapted for receiving a protrusion block that protrudes from a back surface of the mounting board of the module opposite to amounting surface on which electrical devices are mounted. The device further comprises a pump unit including an accommodating case disposed in a pump mounting region located on the upper surface of the body of the heat-dissipating member and filled with a coolant fluid, a set of pump blades disposed inside of the accommodating case and arranged at a lower end of a rotary shaft extending downwardly from a top wall of the accommodating case, and a passive magnet disposed at an upper end of the rotary shaft. The device further comprises a fluid conduit filled with the same coolant fluid as that filled within the accommodating case of the pump unit. The fluid conduit is in fluid communication with the accommodating case, so that the coolant fluid is allowed to circulate between the fluid conduit and the accommodating case. The device further comprises a fan unit disposed on the heat dissipating fins of the metallic heat dissipating member and including a driving shaft having a lower end extending downwardly close to the passive magnet, and an active magnet mounted at the lower end of the driving shaft. When the fan unit is activated, the active magnet is rotated with the driving shaft, so that the passive magnet is rotated with the active magnet by which the pump blades are driven to rotate, whereby the coolant fluid filled in the fluid conduit is circulated at high speed. 
     According to another technical feature of the invention, a heat dissipating device is provided. The heat dissipating device is adapted for use in combination with a module provided with amounting board, which comprises: a first metallic heat dissipating member including a body having a upper surface and a lower surface and a plurality of spaced-apart heat dissipating fins extending upwardly from the upper surface of the body, wherein the body is formed at the upper surface thereof with a pump unit installation recess; a pump unit including an accommodating case disposed in the pump unit installation recess of the body of the first metallic heat dissipating member and filled with a coolant fluid, a set of pump blades disposed inside of the accommodating case and arranged at a lower end of a rotary shaft extending downwardly from a top wall of the accommodating case, and a passive magnet disposed at an upper end of the rotary shaft; a fan unit disposed on the heat dissipating fins of the first metallic heat dissipating member and including a driving shaft having a lower end extending downwardly close to the passive magnet, and an active magnet mounted at the lower end of the driving shaft, wherein when the fan unit is activated, the active magnet is rotated with the driving shaft, so that the passive magnet is rotated with the active magnet; a second metallic heat dissipating member disposed aside the first metallic heat dissipating member, including a body mounted on a surface of the mounting board of the module, the body being provided with a plurality of upwardly extending heat dissipating fins and having a lower surface formed with an accommodating recess at a position corresponding to the module; and a fluid conduit filled with the same coolant fluid as that filled within the accommodating case of the pump unit, wherein the fluid conduit is in fluid communication with the accommodating case, and wherein the fluid conduit has an interconnection portion configured to extend through the body of the second metallic heat dissipating member, so that the coolant fluid is allowed to circulate between the fluid conduit and the accommodating case. 
     According to still another technical feature of the invention, a heat dissipating device is provided. The heat dissipating device is adapted for use in combination with a module provided with a mounting board, which comprises a metallic heat dissipating member disposed on a backside of the mounting board of the module, including a generally disc-shaped body, a plurality of heat dissipating fins, each having an upper end and a lower end, and a circular collecting pipe, wherein the body has a lower surface in contact with the backside of the mounting board of the module and is formed inside with a collecting annulus extending along the periphery thereof and has an upper surface formed with a pump unit installation recess, and wherein the heat dissipating fins extend upwardly from the upper surface of the body and radially arranged along the periphery of the body in a manner spaced apart from one another, each being formed with at least one channel that extends from the upper end to the lower end thereof and coupled in fluid communication with the collecting annulus, and wherein the circular collecting pipe is disposed at the upper ends of the heat dissipating fins and coupled in fluid communication with the channels of the heat dissipating fins; a fan unit including a driving shaft, a set of fan blades and an active magnet, wherein the driving shaft has a lower end extending close to the body, and wherein the fan blades are mounted at an upper end of the driving shaft in such a manner that when the driving shaft is driven to rotate, the fan blades are rotated with the driving shaft, and wherein the active magnet is mounted at a lower end of the driving shaft in such a manner that the active magnet is rotatable with the driving shaft; a pump unit including an accommodating case, a set of pump blades and a passive magnet, wherein the accommodating case  20  is disposed in the pump unit installation recess  104  of the body, so that the accommodating case has a top wall positioned close to the active magnet, and wherein the pump blades are arranged at a lower end of amounting shaft extending downwardly from the top wall of the accommodating case, and wherein the passive magnet is disposed at an upper end of the mounting shaft at a position close to the top wall of the accommodating case and further connected to the pump blades, such that the passive magnet is rotatable with the pump blades; an outlet conduit having an input end provided inside of the body and in fluid communication with a fluid output port of the accommodating case, and an output end extending upwardly and provided in fluid communication with the collecting pipe; and an inlet conduit disposed within the body, having an output end in fluid communication with a fluid input port of the accommodating case and an input end in fluid communication with the collecting annulus. 
     According to still another technical feature of the invention, a heat dissipating device is provided. The heat dissipating device is adapted for use in combination with a module provided with a transparent mounting board and a plurality of light-emitting diodes mounted on a mounting surface of the mounting board, which comprises: a thermally conductive unit including a mounting substrate, and a plurality of conductors disposed on the mounting substrate, wherein the mounting substrate has a first mounting surface and a second mounting surface which is opposite to the first mounting surface and overlaid with predetermined circuit traces, and wherein each of the conductors includes a first terminal electrically connected to the corresponding circuit traces provided on the second mounting surface of the mounting substrate and a second terminal electrically connected to one of the light-emitting diodes located in the module, so that when the respective conductors are provided with electric power, the second terminals have a lower temperature as compared to the first terminals, thereby reducing the working temperature of the light-emitting diodes; and a fan unit mounted on the first mounting surface of the mounting substrate. 
     According to still another technical feature of the invention, a light-emitting diode module is provided. The light-emitting diode module comprises: a transparent mounting board; a plurality of light-emitting diodes mounted on a mounting surface of the mounting board; a plurality of lenses mounted on a back surface of the mounting board opposite to the mounting surface at positions corresponding to the light-emitting diodes; a thermally conductive unit including a mounting substrate, and a plurality of conductors disposed on the mounting substrate, wherein the mounting substrate has a first mounting surface and a second mounting surface which is opposite to the first mounting surface and overlaid with predetermined circuit traces, and wherein each of the conductors includes a first terminal electrically connected to the corresponding circuit traces provided on the second mounting surface of the mounting substrate and a second terminal electrically connected to one of the light-emitting diodes located in the module, so that when the respective conductors are provided with electric power, the second terminals have a lower temperature as compared to the first terminals, thereby reducing the working temperature of the light-emitting diodes; and a fan unit mounted on the first mounting surface of the mounting substrate. 
     According to a yet still another technical feature of the invention, a solar cell module is provided. The solar cell module comprises a transparent mounting board; a transparent conductive layer mounted on amounting surface of the mounting board; a plurality of solar cells mounted on the mounting surface of the mounting board by means of the transparent conductive layer; a plurality of lenses mounted on a back surface of the mounting board opposite to the mounting surface at positions corresponding to the solar cells; a thermally conductive unit including a mounting substrate, and a plurality of conductors disposed on the mounting substrate, wherein the mounting substrate has a first mounting surface and a second mounting surface which is opposite to the first mounting surface and overlaid with predetermined circuit traces, and wherein each of the conductors includes a first terminal electrically connected to the corresponding circuit traces provided on the second mounting surface of the mounting substrate and a second terminal electrically connected to one of the solar cells located in the module, so that when the respective conductors are provided with electric power, the second terminals have a lower temperature as compared to the first terminals, thereby reducing the working temperature of the solar cells; and a fan unit mounted on the first mounting surface of the mounting substrate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and effects of the invention will become apparent with reference to the following description of the preferred embodiments taken in conjunction with the accompanying drawings, in which: 
         FIGS. 1 to 3  are schematic diagrams illustrating the heat dissipating device according to the first preferred embodiment of the invention; 
         FIGS. 4 to 5  are schematic diagrams of alternative examples of the LED modules using the heat dissipating device according to the invention, showing that some of the electrical elements used therein are modified; 
         FIGS. 6 to 8  are schematic diagrams of the heat dissipating device according to the second preferred embodiment of the invention; 
         FIG. 9  is a schematic circuit block diagram for the safety protection device used in the heat dissipating device of the invention; 
         FIGS. 10 and 11  are schematic diagrams of the heat dissipating device according to the third preferred embodiment of the invention; 
         FIGS. 12 to 14  are schematic diagrams of assistant heat dissipating members suitable for use in the heat dissipating device of the invention; 
         FIGS. 15 to 19  are schematic diagrams of the heat dissipating device according to the fourth preferred embodiment of the invention; 
         FIG. 20  is a schematic cross-sectional view of the heat dissipating device according to the fifth preferred embodiment of the invention; 
         FIG. 21  is a schematic cross-sectional view of the heat dissipating device according to the sixth preferred embodiment of the invention; 
         FIG. 22  is a schematic cross-sectional view of an alternative example of the heat dissipating device according to the first preferred embodiment of the invention; 
         FIGS. 23A and 23B  are schematic diagrams of an alternative example of the heat dissipating device according to the sixth preferred embodiment of the invention; 
         FIG. 24  is a schematic cross-sectional view of an alternative example of the heat dissipating device according to the sixth preferred embodiment of the invention; 
         FIGS. 25A and 25B  are schematic diagrams of another alternative example of the heat dissipating device according to the sixth preferred embodiment of the invention; 
         FIG. 26  is a schematic exploded view of another alternative example of the heat dissipating device according to the sixth preferred embodiment of the invention; 
         FIG. 27  is a schematic cross-sectional diagram, showing that the heat dissipating device according to the invention is used in combination with a memory module; and 
         FIG. 28  is a schematic cross-sectional view of an alternative example of the heat dissipating device according to the first preferred embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1 to 3  are schematic diagrams illustrating the heat dissipating device according to the first preferred embodiment of the invention. In  FIG. 3 , the fan blades  32  of the fan unit  3  are removed from the mounting frame  30  for clarity. 
     Referring to  FIGS. 1-3 , the heat dissipating device according to the first preferred embodiment of the invention generally comprises a metallic heat-dissipating member  1 , a pump unit  2 , a fluid conduit  4  and a fan unit  3 . 
     The metallic heat-dissipating member  1  includes a generally rectangular-shaped body  10  and a plurality of spaced-apart heat dissipating fins  11  extending upwardly from an upper surface  102  of the body  10 . The body  10  is formed at its central portion with a through hole  12  that communicates the upper surface  102  with a lower surface  101  of the body  10 . In this embodiment, the through hole  12  is adapted for receiving a protrusion block  91  that protrudes from a back surface of a mounting board  90  of a light-emitting diode module  9 , the back surface being opposite to the mounting surface on which light-emitting diodes  92  are mounted. In other words, the heat dissipating device disclosed herein is arranged to reducing the working temperature of the LED module  9 . 
     In this embodiment, the heat-dissipating member  1  is made of aluminum. However, the heat-dissipating member  1  can alternatively be made of any material suitable for the heat-dissipating purpose. In addition, the upper surface  102  of the body  10  includes a central region on which a pump is mounted and, hence, there is no heating dissipating fin  11  installed in the pump mounting region, as shown in  FIGS. 1 and 2 . 
     The pump unit  2  includes an accommodating case  20 , a set of pump blades  21  and a passive magnet  22 . 
     The accommodating case  20  is disposed in the pump mounting region of the upper surface  102  of the body  10  of the heat-dissipating member  1  in such a manner that the interior space of the accommodating case  20  is accessible through the through hole  12  of the body  10 . The accommodating case  20  is further provided with a fluid input port  200  and a fluid output port  201 . The interior space of the accommodating case  20  is filled with a coolant fluid  29 . In this embodiment, the accommodating case  20  is preferably made from metal material. However, the accommodating case  20  can alternatively be made of any other suitable material. 
     The pump blades  21  are disposed inside of the accommodating case  20  and arranged at a lower end of a rotary shaft  23  extending downwardly from a top wall of the accommodating case  20 . In this embodiment, the pump blades  21  are preferably made from metal material. However, the pump blades  21  can alternatively be made of any other suitable material, such as a plastic material. 
     The passive magnet  22  is installed at an upper end of the rotary shaft  23  at a position close to the top wall of the accommodating case  20 . 
     The fluid conduit  4  is filled with the same coolant fluid  29  as that filled within the accommodating case  20  of the pump unit  2 . The fluid conduit  4  is equipped with a fluid outlet  40  in fluid communication with the fluid input port  200  of the accommodating case  20 , a fluid inlet  41  in fluid communication with the fluid output port  201  of the accommodating case  20 , and an interconnection portion  42  coupled in fluid communication with both of the fluid outlet  40  and the fluid inlet  41  and extending in a meandering manner through the heating dissipating fins  11  (see  FIG. 2 ). By virtue of this arrangement, when the pump blades  21  of the pump unit  2  are rotated, the coolant fluid  29  is propelled to circulate within the fluid conduit  4  and the accommodating case  20 . 
     The fan unit  3  includes a mounting frame  30 , a driving shaft  31  arranged perpendicular to the body  10 , a set of fan blades  32 , and an active magnet  33 . 
     The mounting frame  30  is disposed on the heat dissipating fins  11  of the metallic heat dissipating member  1  by any suitable process known in the art. 
     The driving shaft  31  is rotatably installed in the mounting frame  30  and driven by a motor (not shown). The driving shaft  31  is registered with the mounting shaft  23  of the pump unit  2  and the lower end thereof extends downwardly close to the top wall of the accommodating case  20  of the pump unit  2 . 
     The fan blades  32  are mounted at an upper end of the driving shaft  31  in such a manner that when the driving shaft  31  is driven to rotate, the fan blades  32  are rotated with the driving shaft  31 . It should be noted that the fan blades  32  are adapted for being rotated at a rotation speed of thousands revolutions per minute according to this embodiment. 
     The active magnet  33  is mounted at the lower end of the driving shaft  31 , so that it is rotatable with the driving shaft  31 . Owing to the magnetic force, the rotation of the active magnet  33  causes the passive magnet  22  of the pump unit  2  to rotate, thereby in turn causing the pump blades  21  to rotate. 
     By virtue of the arrangement described above, the fluid conduit  4  is brought in contact with the body  10  and heat dissipating fins  11  of the heat dissipating member  1 . As such, when the fan blades  32  of the fan unit  3  are rotated at a high speed of thousands rpm, the active magnet  33  and the passive magnet  22  are both rotated at high speed with the fan blades  32 , such that the pump blades  21  are rotated at high speed to effect a high-speed circulation of the coolant fluid  29  within the fluid conduit  4 . The temperature of the LED module  9  is reduced by the heat exchange of the coolant fluid  29  inside the fluid conduit  4  with the body  10  and heat dissipating fins  11 . 
     Since the fan blades  32  are rotated at high speed, the pump blades are similarly rotated at high speed, such that the fluid flows rapidly within the fluid conduit  4  to achieve heat exchange with high efficiency. Moreover, since the interconnection portion  42  of the fluid conduit  4  is configured to extend in a meandering manner through the body  10  and the heating dissipating fins  11  of the heat dissipating member  1 , the contact area between the fluid conduit  4  and the body  10  and heating dissipating fins  11  of the heat dissipating member  1  is increased, whereby the heat dissipating efficiency is enhanced. In addition, the high-speed agitation of the coolant fluid  29  within the accommodating case  20  by the pump blades  21  further generates a cooling effect on the coolant fluid  29 . 
     On the other hand, the upward or downward air flow generated by the fan blades  32  causes air convection which will enhance the cooling effect further. 
     The coolant fluid  29  filled within the fluid conduit  4  may optionally be water, water supplemented with a coolant solution, water supplemented with a liquid having a low combustion point and the like. For example, the coolant fluid  29  can contain 50% alcohol and 50% water. Particularly preferred is a coolant fluid  29  supplemented with a liquid having a low combustion point, in view of its natural tendency of being gasified. That is, the coolant fluid  29  of this type, when gasified, exhibits an elevated flow speed and, therefore, an enhanced heat change efficiency. Meanwhile, since the coolant fluid  29  is a mixture having a significant water content, it does not present any risk to safety. Alternatively, the coolant fluid  29  is a gas. 
     Further, given the inventive design, in which the driving shaft  31  of the fan unit  3  is registered with the mounting shaft  23  of the pump unit  2  and the active magnet  32  is prevented from having direct contact with the passive magnet  22 , the fluid conduit  4  and the accommodating case  20  of the pump unit  2  can be tailored to have a vacuum interior space, so as to prevent the coolant fluid  29  filled within the fluid conduit  4  and the accommodating case  20  of the pump unit  2  from leakage. 
     In  FIG. 1 , the respective LED packages  92  are wire bonded to the LED module  9 . However, the LED packages  92  can alternatively be flip-chip bonded to the module as shown in  FIG. 4 , or the LED packages  92  are commercially available emitters as shown in  FIG. 5 . 
       FIGS. 6 to 8  are schematic diagrams of the heat dissipating device according to the second preferred embodiment of the invention.  FIG. 6  is a schematic side view of the heat dissipating device according to the second preferred embodiment of the invention.  FIG. 7  is a schematic top view of the device, in which the fan unit is omitted for brevity.  FIG. 8  is another schematic top view of the device, in which the fan unit and heat dissipating fins are omitted for brevity. 
     Referring to the embodiment shown in  FIGS. 6-8 , the accommodating case  20  of the pump unit  2  is disposed within the through hole  12 . The pump unit  2  according to this embodiment has the same configuration as that described in the first preferred embodiment and, thus, is not repeated herein. Further, the interconnection portion  42  of the fluid conduit  4  does not only pass through the heat dissipating fins  11 , but also through the body  10 . 
       FIG. 9  is a schematic circuit block diagram for the safety protection device used in the heat dissipating device of the invention. 
     As shown in  FIG. 9 , the safety protection device generally includes a PTR temperature variable resistor  35  coupled in series between a fan motor  34  and a fan power source  36  of the fan unit  3 , a vacuum circuit breaker  37  electrically connected to the fan power source, a control circuit  39  electrically connected to the circuit breaker  3   7 , and a sensor  3   8  electrically connected to the control circuit  39  and adapted for detecting the rotation speed of the fan motor  34 . 
     The variable resistor  35  is one whose electrical resistance varies in inverse proportion to temperature. The variable resistor  35  is disposed on the body  10  of the heat dissipating member  1 , so that the electrical resistance thereof is varied in inverse proportion to the temperature of the body  10  of the heat dissipating member  1 . In other words, the electrical resistance value of the variable resistor  35  is reduced as the temperature of the body  10  of the heat dissipating member  1  goes up, thereby rendering the fan motor  34  to drive the fan blades  32  to rotate at higher speed. On the other hand, when the temperature of the body  10  of the heat dissipating member  1  goes down, the electrical resistance value of the variable resistor  35  is increased, so that the fan motor  34  drives the fan blades  32  to rotate at lower speed. 
     The circuit breaker  37  is operable to interrupt power supply from the fan power source  36 . 
     The sensor  38  is employed to generate a detection signal indicative of the rotation speed of the fan motor  34  upon detecting the rotation speed of the fan motor  34 . The control circuit  39  receives the detection signal and compares the same with a reference signal representing a normal rotation speed of the motor. When the detection signal is found to be greater than the reference signal, it indicates that the motor  34  is rotated at a higher speed than the normal rotation and water leakage occurs. In this case, the control circuit  39  will output an activating signal to the circuit breaker  37 , so that the circuit breaker  37  is activated to interrupt power supply from the fan power source  36  to secure safety. 
       FIGS. 10 and 11  are schematic diagrams of the heat dissipating device according to the third preferred embodiment of the invention. 
     As shown in  FIGS. 10 and 11 , the heat dissipating device according to the third preferred embodiment of the invention generally includes a first metallic heat dissipating member  1 , a pump unit  2 , a fan unit  3 , a fluid conduit  4  and a second metallic heat dissipating member  7 . 
     The second metallic heat dissipating member  7  comprises a body  70  mounted on a surface of the LED module  9 . The body  70  is provided with a number of upwardly extending heat dissipating fins  71  and has a lower surface  701  formed with an accommodating recess  703  at a position corresponding to the LED module  9 . 
     An assistant heat dissipating pad  5 , which may by way of example be made of copper, is disposed within the accommodating recess  703  of the body  70  in such a manner that the assistant heat dissipating pad  5  contacts the backside of the mounting board  90  of the LED module  9 , thereby enhancing the heat exchange between the heat dissipating member  7  and the LED module  9 . A reservoir  43  is formed at the interconnection portion  42  of the fluid conduit  4  in a manner corresponding to the assistant heat dissipating pad  5 , so as to allow heat exchange of the coolant fluid  29  filled in the reservoir  43  with the assistant heat dissipating pad  5 , thereby reducing the working temperature of the LED module  9  further. 
     The first metallic heat dissipating member  1  includes a body  10  disposed on the second metallic heat dissipating member  7  and a number of upwardly extending heat dissipating fins  11 . The body  10  is formed at its upper surface  102  with a pump unit installation recess  104  for receiving the accommodating case  20  of the pump unit  2 . The rest parts of the pump unit  2  according to this embodiment have the same configurations as those shown in  FIGS. 1 and 6  and, thus, are not repeated herein. 
     The fan unit  3  described in this embodiment has the same configuration as those shown in  FIGS. 1 and 6  and, thus, is not repeated herein. 
       FIGS. 12 to 14  are schematic diagrams of assistant heat dissipating members suitable for use in the heat dissipating device of the invention. 
     As shown in  FIGS. 12 to 14 , the respective assistant heat dissipating members  13  are attached to surfaces of the heat dissipating fins  11  of the metallic heat dissipating member  1 . 
     The assistant heat dissipating members  13  may by way of example be configured in the form of the so-called heat pipes, each includes a bottom layer  130 , an intermediate layer  131 , a first copper foil  132  and a second copper foil  133 , and a top layer  134 . 
     The bottom layer  130  is a flexible film made of a polyimide (PI) and a butadiene-styrene copolymer (BS). The bottom layer  130  has a first surface  1300  intimately attached to a surface of a corresponding heat dissipating fin  11  and a second surface  1301  opposite to the first surface  1300 . The first copper foil  132  is placed on the second surface  1301  by, for example, printing, with both ends  1320  extending beyond the edges of the bottom layer  130 . It should be noted that the first copper foil  132  can be substituted with any suitable metal foil. 
     The intermediate layer  131  is formed on the first copper foil  132 . According to this embodiment, the intermediate layer  131  is made of photoresist material. The intermediate layer  131  is formed with a number of slots  1310  which extend from one end to the other end of the intermediate layer  131  and extend all the way through the thickness of the intermediate layer  131 . The intermediate layer  131  is subjected to a sintering process, so that the respective slots  1310  are formed at walls thereof with a plurality of apertures  1311 . 
     The second copper foil  133  is disposed on the intermediate layer  131  by the same way as described for the first copper foil  132 . Likewise, both ends  1330  of the second copper foil  133  extend beyond the edges of the intermediate layer  131 . 
     The top layer  134  is made of the same material as described above for the bottom layer  130  and disposed on the second copper foil  133 . 
     Both ends  1320 , 1330  of the first and second copper foils  132 , 133  of the respective assistant heat dissipating members  13  are in contact with corresponding heat dissipating fins  11  and the body  10 . 
     By virtue of the arrangement described above, the first and second copper foils  132 , 133  are allowed to perform heat exchange with the body  10  and the heat dissipating fins  11 , thereby enhancing the heat dissipation effect. It should be noted that the apertures  1310  of the intermediate layer  131  may be filled with a fluid having a low combustion point, so that the fluid is rapidly gasified when the first and second copper foils  132 , 133  perform heat exchange with the body  10  and the heat dissipating fins  11 . The gasified low combustion point fluid will later return back to the liquid form in the apertures  1310  due to capillary condensation. 
       FIGS. 15 to 19  are schematic diagrams of the heat dissipating device according to the fourth preferred embodiment of the invention. 
     According to the embodiment shown in  FIGS. 15 to 19 , the heat dissipating device disclosed herein generally comprises a metallic heat dissipating member  1 ′, a fan unit  3 , a pump unit  2 , a L-shaped outlet conduit  106 , an inlet conduit  107 , and a plurality of assistant heat dissipating members  13 . 
     The metallic heat dissipating member  1 ′ is disposed on the backside of the mounting board  90  of the LED module  9  and includes a generally disc-shaped body  10 ′, a plurality of heat dissipating fins  11 ′, and a circular collecting pipe  14 . 
     The body  10 ′ has a lower surface  101 ′ in contact with the backside of the mounting board  90  of the LED module  9 . Meanwhile, as shown in  FIG. 19 , the body  10 ′ is formed inside with a collecting annulus  105  extending along the periphery thereof. A pump unit installation recess  104  is formed on the upper surface  102 ′ of the body  10 . 
     The plurality of heat dissipating fins  11 ′ extend upwardly from the upper surface  102 ′ of the body  10 ′ and radially arranged along the periphery of the body  10 ′ in a manner spaced apart from one another. Each of the heat dissipating fins  11 ′ is formed with at least one channel  110  that extends from the upper end to the lower end thereof and is coupled in fluid communication with the collecting annulus  105 . 
     The circular collecting pipe  14  is disposed at the upper ends of the heat dissipating fins  11 ′ and coupled in fluid communication with the channels  110  of the heat dissipating fins  11 ′. 
     The fan unit  3  includes a mounting frame  30 , a driving shaft  31  arranged perpendicular to the body  10 ′, a set of fan blades  32 , and an active magnet  33 . 
     The mounting frame  30  is surrounded by and connected to the heat dissipating fins  11 ′, so that it is held at a height close to that of the circular collecting pipe  14 . 
     The driving shaft  31  is rotatably installed in the mounting frame  30  as described in the embodiments above. The driving shaft  31  has a lower end extending downwardly close to the body  10 ′. 
     The fan blades  32  are mounted at an upper end of the driving shaft  31  in such a manner that when the driving shaft  31  is driven to rotate, the fan blades  32  are rotated with the driving shaft  31 . 
     The active magnet  33  is mounted at the lower end of the driving shaft  31 , so that it is rotatable with the driving shaft  31 . 
     The pump unit  2  includes an accommodating case  20 , a set of pump blades  21  and a passive magnet  22 . 
     The accommodating case  20  is disposed in the pump unit installation recess  104  of the body  10 ′, so that the top wall of the accommodating case  20  is positioned close to the active magnet  33 . The accommodating case  20  is provided with a fluid input port  200  and a fluid output port  201 . In this embodiment, the accommodating case  20  is preferably made from metal material. 
     The pump blades  21  are rotatably arranged at the lower end of the mounting shaft  23  extending downwardly from the top wall of the accommodating case  20 . In this embodiment, the pump blades  21  are preferably made from metal material. 
     The passive magnet  22  is rotatably disposed at the upper end of the mounting shaft  23  at a position close to the top wall of the accommodating case  20 . The passive magnet  22  is further connected to the pump blades  21 , such that it is rotatable with the pump blades  21 . 
     The outlet conduit  106  has an input end  1060  provided inside of the body  10 ′ and in fluid communication with the fluid output port  201  of the accommodating case  20 , and an output end  1061  extending upwardly and provided in fluid communication with the collecting pipe  14 . 
     The inlet conduit  107  is disposed within the body  10 ′ and has an output end  1070  in fluid communication with the fluid input port  200  of the accommodating case  20  and an input end  1071  in fluid communication with the collecting annulus  105 . 
     The assistant heat dissipating members  13  have the same configuration as that shown in  FIGS. 12 to 14 . The respective assistant heat dissipating members  13  are attached to the lower surface  101 ′ of the body  10 ′ and extend to outer surfaces of corresponding heat dissipating fins  11 ′, so as to perform heat exchange with the coolant fluid  29  filled within the corresponding heat dissipating fins  11 ′, thereby further enhancing the heat dissipation effect. 
     In the arrangement described above, when the pump blades  21  are rotated in response to the rotation of the fan blades  32 , the coolant fluid  29  is further delivered from the accommodating case  20  to the collecting pipe  14  through the outlet conduit  106 , and further delivered to the collecting annulus  105  via the channels  110 , and finally returns back to the accommodating case  20  via the inlet conduit  107 . 
       FIG. 20  is a schematic cross-sectional view of the heat dissipating device according to the fifth preferred embodiment of the invention. 
     According to the embodiment shown in  FIG. 20 , the heat dissipating device disclosed herein comprises a fan unit  3  and a thermally conductive unit  6 . 
     The thermally conductive unit  6  includes a mounting substrate  60 , and a plurality of conductors  61  disposed on the mounting substrate  60  and made of semiconductor material. 
     According to this embodiment, the mounting substrate  60  is a ceramic substrate having a first mounting surface and a second mounting surface which is opposite to the first mounting surface and overlaid with predetermined circuit traces  600 . The fan unit  3  is mounted on the first mounting surface of the mounting substrate  60 . 
     Each of the conductors  61  includes a first electrode  610  electrically connected to the corresponding circuit traces provided on the second mounting surface of the mounting substrate  60  and a second electrode  611  electrically connected to an LED  92  located in the LED module  9 . In this embodiment, the first electrodes  610  of the respective conductors  61  are P-type electrodes, whereas the second electrodes  611  are N-type electrodes. Therefore, when the respective conductors  61  are provided with electric power via the circuit traces  600 , they facilitate the heat transfer from the ends remote from the mounting substrate  60  towards the opposite ends thereof which are close to the mounting substrate  60 . 
     The LED module  9  has a transparent mounting board  90  and a plurality of LEDs  92  operatively mounted on the mounting surface of the mounting board  90 . Each of the LEDs has a first electrode  920  connected to the second electrode  611  of the corresponding conductor  61  of the conductive unit  6 , and a second electrode  921  electrically connected to the corresponding circuit traces  98  provided on the mounting board  90 , so as to allow the conductors  61  to reduce the working temperature of the LEDs  92 . 
     It should be noted that the LED module  9  disclosed herein further comprises a plurality of lenses  93  mounted on a back surface of the mounting board  90  opposite to the mounting surface at positions corresponding to the LEDs  92 , and a reflective plate  94  which surrounds the lenses  93 . The respective lenses  93  have a single arc-shaped outer surface as shown in  FIG. 20 , but may alternatively be configured to have a number of flat outer surfaces. 
       FIG. 21  is a schematic cross-sectional view of an alternative example of the heat dissipating device according to the fifth preferred embodiment of the invention, which differs from the fifth preferred embodiment in that the heat dissipating device is used in combination with a solar cell module. The solar cell module comprises a mounting board  90 ′, a plurality of solar cells  95  operatively mounted on a mounting surface of the mounting board  90 ′ by means of a transparent conductive layer  96 , and a plurality of lenses  93  mounted on a back surface of the mounting board  90 ′ opposite to the mounting surface at positions corresponding to the solar cells  95 . 
     It should be noted that the alternative example may be additionally include a light converging cover  900  for converging the emitted light, which is provided on the mounting board  90 ′ in a manner covering the lenses  93 . 
       FIG. 22  is a schematic cross-sectional view of an alternative example of the heat dissipating device according to the first preferred embodiment of the invention. 
     The alternative example shown in  FIG. 22  differs from the first preferred embodiment in that the mounting board  90  of the LED module  9  disclosed herein is a transparent mounting board, and that the LEDs  92  are operatively mounted on a surface of a protrusion block  91  extending from the backside of the mounting board  90 , and that the coolant fluid  29  flowing within the accommodating case  20  and the fluid conduit  4  does not exhibit any electrical conductivity. 
       FIGS. 23A and 23B  are a schematic cross-sectional view and a schematic exploded view of the heat dissipating device according to the sixth preferred embodiment of the invention, respectively. 
     As shown in  FIGS. 23A and 23B , the heat dissipating device according to this embodiment comprises a thermally conductive unit  6 . The thermally conductive unit  6  includes an elongated mounting substrate  60  with thermal conductivity. The thermally conductive mounting substrate  60  has a mounting surface on which predetermined circuit traces  62  are provided adjacent to an end of the substrate  60  ( FIG. 23B  illustrates only part of the circuit traces  62 ). 
     The LEDs  92  of the LED module  9  are arranged in an array and operatively mounted on the mounting surface of the mounting substrate  60 , so that the electrodes of the LEDs  92  (not shown) are electrically connected to the corresponding circuit traces  62 . In addition, the mounting surface of the mounting substrate  60  on which the LEDs  92  are mounted is coated with a phosphor powder layer  97  in a manner covering the LEDs  92 . 
       FIG. 24  is a schematic cross-sectional view of an alternative example of the heat dissipating device according to the sixth preferred embodiment of the invention. 
     The alternative example shown in  FIG. 24  differs from the embodiment shown in  FIGS. 23A and 23B  in that the LEDs  92  are wire bonded to the mounting surface of the mounting substrate  60  through wires  98 . 
       FIGS. 25A and 25B  are a schematic cross-sectional view and a schematic exploded view of another alternative example of the heat dissipating device according to the sixth preferred embodiment of the invention, respectively. 
     The alternative example shown in  FIGS. 25A and 25B  differs from the embodiment shown in  FIGS. 23A and 23B  in that the LEDs  92  are those commercially available under the trade name Emitter Star and, hence, the phosphor powder layer shown in  FIGS. 23A and 23B  is omitted. 
       FIG. 26  is a schematic exploded view of another alternative example of the heat dissipating device according to the sixth preferred embodiment of the invention. 
     As shown in  FIG. 26 , a coolant fluid pack  63  is provided at an end of the thermally conductive mounting substrate  60  opposite to the end where the circuit traces  62  are overlaid, so that the pack  63  houses a part of the opposite end. The coolant fluid pack  63  is filled with the coolant fluid  29 , so as to enhance the ability of the thermally conductive mounting substrate  60  to reduce the working temperature of LEDs  92 . 
       FIG. 27  is a schematic cross-sectional diagram, showing that the heat dissipating device according to the invention is used in combination with a memory module. 
     As shown in  FIG. 27 , the memory module  9  includes amounting board  90  and a plurality of memory devices  92  operatively mounted on the mounting board  90 . The memory module  9  is disposed beneath the body  10 , so that non-electrode mounting surfaces of the memory devices  92  are in contact with the lower surface of the body  10 , thereby dissipating the heat generated due to operation of the memory module  9  through the body  10 . 
       FIG. 28  is a schematic cross-sectional view of an alternative example of the heat dissipating device according to the first preferred embodiment of the invention. 
     The alternative example shown in  FIG. 28  differs from the first preferred embodiment in that the module  9  is semiconductor integrated circuit module. The mounting board  90  of the module  9  has a lower surface on which electrically conductive linkers  93  are mounted and a number of semiconductor integrated circuits are operatively mounted on a surface of a protrusion block  91  extending from the mounting board  90 . 
     In conclusion, the heat dissipating devices and the modules using the same as disclosed herein can surely achieve the intended objects and effects of the invention by virtue of the structural arrangements described above. 
     While the invention has been described with reference to the preferred embodiments above, it should be recognized that the preferred embodiments are given for the purpose of illustration only and are not intended to limit the scope of the present invention and that various modifications and changes, which will be apparent to those skilled in the relevant art, may be made without departing from the spirit of the invention and the scope thereof as defined in the appended claims.