1. Field of the Invention
The present invention relates to a heat dissipation module and a portable device; more particularly, the present invention relates to a heat dissipation module and a portable device having the capability of lowering the temperature of a heating element.
2. Description of the Related Art
Generally, an electronic device comprises various kinds of circuit boards, and each circuit board has various kinds of heating elements (such as a chip). When the heating element is working, it generates a huge amount of heat, thereby increasing its temperature. If the heat cannot be effectively and immediately dissipated, the operation of the electronic device may be affected. More seriously, the heating element might be damaged due to overheating. In order to ensure that the heating element can work properly, it is common practice to install a heat dissipation module on the heating element, so as to conduct the heat generated by the heating element to the heat dissipation module and thereby achieve the object of lowering the temperature of the heating element.
There are two major types of heat dissipation modules—an active heat dissipation module and a passive heat dissipation module. An active heat dissipation module, such as a cooling fan or a water-cooling device, needs additional driving energy to perform a heat dissipation action. A passive heat dissipation module, such as a cooling fin, does not need additional driving energy. Although an active heat dissipation module has a better heat dissipation effect than that of a passive heat dissipation module, an active heat dissipation module has a higher cost and needs a larger space for installation. Therefore, an active heat dissipation module is more suitable for installation in a large-scale electronic device (such as the motherboard of a desktop computer). As a result, the scope of applications of an active heat dissipation module is much smaller than that of a passive heat dissipation module.
With regard to a modern passive heat dissipation module, in order to enhance its heat dissipation effect, a layer of thermal grease is applied on a surface of the passive heat dissipation module that is in contact with the heating element so as to increase the heat conductivity; in addition, the volume of the passive heat dissipation module is enlarged to absorb more heat, or the passive heat dissipation module is designed with fin-like protrusions so as to increase the surface area for heat dissipation.
However, because a passive heat dissipation module is usually made of metal, the following drawbacks are inherent in practical production applications: (1) Because the specific heat of metal is low, the passive heat dissipation module and the heating element reach thermal equilibrium in a short amount of time, which makes the temperature of the heating element rise or fall very quickly; such rapid changes in temperature result in a thermal impact on the heating element and may easily damage the heating element. (2) Because some of the circuit boards of an electronic device need to be vertically installed, the weight of a passive heat dissipation module made of metal, due to the higher specific gravity, might cause the circuit boards to bend and thereby affect the reliability of the electronic device.
In the known prior art, such as Taiwan Patent No. I308047 (Heat dissipation device), a heat dissipation device is disclosed for being used to dissipate heat of an electronic element. The heat dissipation device comprises a heat absorbing portion, a heat dissipating portion jointed with the heat absorbing portion, and a heat storage body jointed with the heat absorbing portion. The heat storage body is a container made of a heat conductive material, and is filled with a phase change material. The phase change material is solid at a normal temperature, and changes from solid to liquid upon being heated. The heat absorbing portion is a base which is directly contacted to a heating electronic element. The heat dissipating portion is a heat sink set disposed on the heat absorbing portion. However, although the known prior art discloses that the heat storage body can be filled with the phase change material, it still has the following drawbacks: (1) The jointed surface area between the heat storage body and the heat absorbing portion is limited; as a result, the heat dissipation efficiency of the heat storage body is lowered; and (2) the phase change temperature of the phase change material is fixed and thus cannot change with the temperature of the heating electronic element.
Therefore, there is a need to provide a heat dissipation module and portable device having the heat dissipation module to mitigate and/or obviate the aforementioned problems.
It is an object of the invention to provide a heat dissipation module and a portable device having the same for lowering the temperature of a heating element.
To achieve the abovementioned object, the heat dissipation module of the invention comprises a heat dissipation module body, a container, and a liquid element. The heat dissipation module body is made of a heat conductive material; the container is installed in the heat dissipation module body; and the liquid element is disposed in the container. Therefore, when the heat dissipation module is in contact with the heating element, heat generated by the heating element can be absorbed by the heat dissipation module body and the liquid element, so as to achieve an effect of lowering the temperature of the heating element. In one embodiment of the invention, the liquid element is water.
To achieve the abovementioned object, the portable device of the invention comprises at least one heating element and at least one heat dissipation module. The at least one heat dissipation module is connected to the at least one heating element. The at least one heat dissipation module comprises a heat dissipation module body, a container, and a liquid element. The heat dissipation module body is made of a heat conductive material; the container is installed in the heat dissipation module body; and the liquid element is disposed in the container. Therefore, when the heat dissipation module is in contact with the heating element, heat generated by the heating element can be absorbed by the heat dissipation module body and the liquid element, so as to achieve an effect of lowering the temperature of the heating element. In one embodiment of the invention, the liquid element is water.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
These and other objects and advantages of the invention will become apparent from the following description of the accompanying drawings, which disclose several embodiments of the invention. It is to be understood that the drawings are to be used for purposes of illustration only, and not as a definition of the invention.
In the drawings, wherein similar reference numerals denote similar elements throughout the several views:
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In one embodiment of the invention, the heat dissipation module body 10 is made of a heat conductive material, and the heat conductive material is selected from, but is not limited to, the following material groups: aluminum, aluminum alloy, copper, copper alloy, silver, and silver alloy.
In order to solve the problem that the heat dissipation module 1 and the heating element 51 reach thermal equilibrium in a short amount of time due to a low specific heat of the metal, as mentioned in known prior arts, in one embodiment of the invention, the liquid element is water, such that it takes longer for the heat dissipation module 1 and the heating element 51 to reach thermal equilibrium because water has the characteristics of a higher specific heat and higher heat of vaporization, and therefore the influence of thermal impact on the heating element 51 can be reduced. Further, because the specific gravity of water (1 g/cm3) is lower than that of most metal materials (for example, the specific gravity of copper is 8.9 g/cm3), a larger volume of the container 20 will allow more water to be contained, and the weight of the heat dissipation module 1 can further be reduced, so as to avoid the drawback that the circuit board 52 is bent due to the weight of the heat dissipation module 1, as mentioned in known prior arts. Please note that the liquid element 30 is not limited to water; the liquid element 30 can be any liquid that has a high specific heat and high heat of vaporization.
The vaporization temperature of water at 1 standard atmospheric pressure (atm) is 100□, but most of the time, the thermal equilibrium temperature of the heating element 51 and the heat dissipation module 1 remains below 100□. In order to make the vaporization temperature of water match the thermal equilibrium temperature of the heating element 51 and the heat dissipation module 1, the invention provides a mechanism capable of changing the vaporization temperature of the liquid element 30 of the heat dissipation module 1.
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According to the above description, the heat dissipation module 1 of the invention has the following advantages: (1) extending the time of reaching thermal equilibrium so as to prolong the usage life of the portable device; and (2) reducing the weight of the heat dissipation module.
Although the invention has been explained in relation to its preferred embodiments, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.
Number | Date | Country | Kind |
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098145568 | Dec 2009 | TW | national |