HEAT DISSIPATION ELEMENT WITH HEAT RESISTANT MECHANISM

Abstract

A heat dissipation element with a heat resistant mechanism is provided. The heat dissipation element is a heat pipe, a loop-type heat pipe or a vapor chamber. A heat resistant layer is properly formed on an inner side or an outer side of the heat dissipation element. Consequently, while the heat is transferred, the tactile temperature of the handheld electronic device is not influenced.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application No. 62/424,012 filed Nov. 18, 2016, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a heat dissipation element, and more particularly to a heat dissipation element with a heat resistant mechanism.

BACKGROUND OF THE INVENTION

Generally, a handheld electronic device such as a mobile phone, a tablet computer or a small-sized NB is equipped with a two-phase heat dissipation element for removing the heat from a chip, a memory or another electronic component of the handheld electronic device. Consequently, the handheld electronic device can be maintained in the normal working state. For example, the two-phase heat dissipation element includes a heat pipe, a loop-type heat pipe or a vapor chamber.

The operating principles of different two-phase heat dissipation elements are similar. For example, the two-phase heat dissipation element absorbs or releases heat during the liquid/gas phase change or the gas/liquid phase change of a working medium. FIG. 1A is a schematic perspective view illustrating an inner heat pipe and a heat generation element in a conventional handheld electronic device. FIG. 1B is a schematic cross-sectional view illustrating the inner structure of the conventional handheld electronic device of FIG. 1A and taken along the line 1B-1B. As shown in FIGS. 1A and 1B, a heat dissipation element installed in a handheld electronic device 1 is a heat pipe 2. The heat pipe 2 comprises a closed pipe body 21 and a capillary structure 22. The capillary structure 22 is disposed within the pipe body 21 and filled with a working medium (not shown). The pipe body 21 is at least divided into an evaporation section (or a heat absorbing section) 21A and a condensation section (or a heat removing section) 21B. When the evaporation section 21A of the heat pipe 2 is in contact with a heat generation element 11 (e.g., a chip or a memory), the working medium absorbs the heat from the heat generation element 11. Consequently, the working medium is changed from a liquid state to a vapor state. Moreover, in response to a pressure difference, the working medium in the vapor state is moved toward the condensation section 21B. Then, the working medium releases the heat in the condensation section 21B. Consequently, the working medium is condensed from the vapor state to the liquid state. Due to the capillary action of the capillary structure 22, the working liquid in the liquid state is returned from the condensation section 21B to the evaporation section 21A. Consequently, a next liquid/gas change process is performed.

However, since the pipe body of the heat dissipation element is usually made of a metallic material, the heat dissipation element still has some drawbacks. For example, while the heat is absorbed by the evaporation section 21A and transferred to the condensation section 21B, the heat is still exhausted to the surroundings through conduction. Under this circumstance, the ambient temperature near the heat dissipation element of the handheld electronic device 1 is largely increased. Moreover, if the heat is transferred to the casing of the handheld electronic device 1, the tactile temperature of holding the handheld electronic device 1 by the user is affected.

For solving the above drawbacks, some approaches have been disclosed in the industries. For example, a heat insulation layer is directly attached on an inner frame of the handheld electronic device. Alternatively, a heat insulation layer is directly attached on an inner portion of the handheld electronic device near the casing. Since the available space inside the handheld electronic device is insufficient, it is difficult to attach the heat insulation layer. Therefore, there is a need of providing an effective approach to solve the drawbacks of the conventional technologies.

The present invention provides a novel design to solve the drawbacks of the conventional technologies. In accordance with the design of the present invention, the heat dissipation element is improved and equipped with an effective heat resistant mechanism to reduce or avoid heat release during the transfer process. Consequently, the ambient temperature near the heat dissipation element is decreased, and the tactile temperature of holding the handheld electronic device by the user is not affected. Moreover, the heat resistant mechanism of the present invention is directly formed on the heat dissipation element. In comparison with the conventional technology requiring the subsequent processing operation of the back-end system vendor, the wishes of the brand manufacturer to purchase the heat dissipation element of the present invention will be increased.

SUMMARY OF THE INVENTION

An object of the present invention is to avoid the problem of largely increasing or centralizing the ambient temperature of the heat dissipation element in the handheld electronic device, so that the normal operation of the nearby electronic component is not adversely affected. Moreover, the heat dissipation element does not increase the tactile temperature of the casing of the handheld electronic device. The heat resistant mechanism is the heat dissipation element itself, is formed on the inner side of the heat dissipation element itself, or is formed on the outer side of the heat dissipation element itself. Consequently, the heat dissipation element is applied to the handheld electronic device. The technology of the present invention can reduce the ambient temperature of the handheld electronic device or the tactile temperature of the casing of the handheld electronic device.

In accordance with an aspect of the present invention, there is provided a heat pipe. The heat pipe includes a pipe body, a capillary structure and a heat resistant layer. The pipe body includes an evaporation section, a heat resistant section and a condensation section. The heat resistant section is arranged between the evaporation section and the condensation section. The capillary structure is disposed within the pipe body. The heat resistant layer is disposed within the pipe body and located at the heat resistant section.

In an embodiment, the capillary structure is arranged between the pipe body and the heat resistant layer.

In an embodiment, the capillary structure is a fiber bundle.

In an embodiment, the capillary structure is a fiber bundle. The heat resistant layer is located beside the fiber bundle. Moreover, the heat resistant layer and the fiber bundle are not overlapped with each other.

In accordance with an aspect of the present invention, there is provided a heat pipe. The heat pipe is in contact with a heat generation element. The heat pipe includes a pipe body, a capillary structure and a heat resistant layer. The pipe body includes an evaporation section and a condensation section. The capillary structure is disposed within the pipe body. The heat resistant layer is disposed within the pipe body. The pipe body has a far side away from the heat generation element. The heat resistant layer is located at the far side of the pipe body.

In an embodiment, the heat resistant layer is formed on an inner side of the capillary structure.

In an embodiment, the heat resistant layer is located at the evaporation section or the condensation section of the pipe body.

In accordance with an aspect of the present invention, there is provided a loop-type heat pipe. The loop-type heat pipe is in contact with a heat generation element. The loop-type heat pipe includes a top plate and a bottom plate. The bottom plate is in contact with the heat generation element. The top plate and the bottom plate are stacked on each other to define an evaporation section, a vapor channel, a condensation section and a liquid channel. A thermal conductivity of the bottom plate is higher than a thermal conductivity of the top plate.

In accordance with an aspect of the present invention, there is provided a loop-type heat pipe. The loop-type heat pipe is in contact with a heat generation element. The loop-type heat pipe includes a top plate, a bottom plate, a vapor channel and a liquid channel. The bottom plate is in contact with the heat generation element. The top plate and the bottom plate are stacked on each other to define an evaporation section and a condensation section. A thermal conductivity of the bottom plate is higher than a thermal conductivity of the top plate. The vapor channel is connected with the evaporation section and the condensation section. The liquid channel is connected with the condensation section and the evaporation section.

In accordance with an aspect of the present invention, there is provided a vapor chamber. The vapor chamber is in contact with a heat generation element. The vapor chamber includes a top thin plate and a bottom thin plate. The bottom thin plate is in contact with the heat generation element. A thermal conductivity of the bottom thin plate is higher than a thermal conductivity of the top thin plate.

In accordance with an aspect of the present invention, there is provided a vapor chamber. The vapor chamber is in contact with a heat generation element. The vapor chamber includes a top thin plate, a bottom thin plate and a heat resistant layer. The bottom thin plate is in contact with the heat generation element. The heat resistant layer is formed on an inner side of the top thin plate.

The above objects and advantages 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. 1A is a schematic perspective view illustrating an inner heat pipe and a heat generation element in a conventional handheld electronic device;

FIG. 1B is a schematic cross-sectional view illustrating the inner structure of the conventional handheld electronic device of FIG. 1A and taken along the line 1B-1B;

FIG. 2A is a schematic perspective view illustrating a heat dissipation element (e.g., a heat pipe) according to a first embodiment of the present invention and a handheld electronic device with the heat dissipation element;

FIG. 2B is a schematic cross-sectional view illustrating the inner structure of the handheld electronic device of FIG. 2A and taken along the line 2B-2B;

FIGS. 3A-3E schematically illustrate some variant examples of the heat dissipation element (e.g., a heat pipe) of the first embodiment installed in the handheld electronic device;

FIG. 4A is a schematic perspective view illustrating a heat dissipation element (e.g., a heat pipe) according to a second embodiment of the present invention and a handheld electronic device using the heat dissipation element;

FIG. 4B is a schematic cross-sectional view illustrating the inner structure of the handheld electronic device of FIG. 4A and taken along the line 4B-4B;

FIGS. 4C and 4D schematically illustrate some variant examples of the heat dissipation element (e.g., a heat pipe) of the second embodiment installed in the handheld electronic device;

FIG. 5A is a schematic perspective view illustrating a heat dissipation element (e.g., a loop-type heat pipe) according to a third embodiment of the present invention and a handheld electronic device using the heat dissipation element;

FIG. 5B is a schematic cross-sectional view illustrating the inner structure of the handheld electronic device of FIG. 5A and taken along the line 5B-5B;

FIG. 6A is a schematic perspective view illustrating a heat dissipation element (e.g., a loop-type heat pipe) according to a fourth embodiment of the present invention and a handheld electronic device using the heat dissipation element;

FIG. 6B is a schematic cross-sectional view illustrating the inner structure of the handheld electronic device of FIG. 6A and taken along the line 6B-6B;

FIG. 7A is a schematic perspective view illustrating a heat dissipation element (e.g., a loop-type heat pipe) according to a fifth embodiment of the present invention and a handheld electronic device using the heat dissipation element;

FIG. 7B is a schematic cross-sectional view illustrating the inner structure of the handheld electronic device of FIG. 7A and taken along the line 7B-7B;

FIG. 7C schematically illustrates a variant example of the heat dissipation element (e.g., a loop-type heat pipe) of the fifth embodiment installed in the handheld electronic device;

FIG. 8A is a schematic perspective view illustrating a heat dissipation element (e.g., a vapor chamber) according to a sixth embodiment of the present invention and a handheld electronic device using the heat dissipation element;

FIG. 8B is a schematic cross-sectional view illustrating the inner structure of the handheld electronic device of FIG. 8A and taken along the line 8B-8B; and

FIGS. 8C and 8D schematically illustrate some variant examples of the heat dissipation element (e.g., a vapor chamber) of the sixth embodiment installed in the handheld electronic device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Please refer to FIGS. 2A and 2B. FIG. 2A is a schematic perspective view illustrating a heat dissipation element (e.g., a heat pipe) according to a first embodiment of the present invention and a handheld electronic device with the heat dissipation element. FIG. 2B is a schematic cross-sectional view illustrating the inner structure of the handheld electronic device of FIG. 2A and taken along the line 2B-2B. In this embodiment, the heat dissipation element is a heat pipe 2. The inner portion of the handheld electronic device 1 comprises an accommodation space. The accommodation space is defined by a backside wall 1A, a lateral wall 1B and a front wall 1C. The heat pipe 2 comprises a closed pipe body 21 and a capillary structure 22. The capillary structure 22 is disposed within the pipe body 21 and filled with a working medium (not shown). The pipe body 21 is at least divided into an evaporation section (or a heat absorbing section) 21A, a heat resistant section 21C and a condensation section (or a heat removing section) 21B. When the evaporation section 21A of the heat pipe 2 is in contact with a heat generation element 11 (e.g., a chip or a memory), the working medium absorbs the heat from the heat generation element 11. Consequently, the working medium is changed from a liquid state to a vapor state. Moreover, in response to a pressure difference, the working medium in the vapor state is moved toward the condensation section 21B through the heat resistant section 21C. The condensation section 21B itself can remove the heat. Optionally, the condensation section 21B is in cooperation with another heat dissipation mechanism (e.g., a heat sink 3 as shown in the drawing) to remove the heat. Consequently, the working medium in the condensation section 21B is condensed from the vapor state to the liquid state. Due to the capillary action of the capillary structure 22, the working liquid in the liquid state is returned from the condensation section 21B to the evaporation section 21A. Consequently, a next liquid/gas change process is performed.

In accordance with a feature of this embodiment, the heat pipe 2 is further equipped with a heat resistant layer 23. The heat resistant layer 23 is located at the heat resistant section 21C between the evaporation section 21A and the condensation section 21B and arranged around the pipe body 21. Consequently, while the working medium in the heat pipe 2 is transferred from the evaporation section 21A to the condensation section 21B, the heat can be transferred to the pipe body 21. Moreover, since the heat resistant layer 23 is arranged around the pipe body 21, the heat cannot be transferred along the radial direction. That is, the heat is guided to be transferred toward the condensation section 21B along the axial direction. Due to the heat resistant layer 23, the ambient temperature of an electronic component 12 near the heat resistant section 21C of the heat pipe 2 is not increased by the heat pipe 2, and the electronic component 12 is maintained in the normal working state. In this embodiment as shown in FIG. 2B, the heat pipe 2 is installed in the handheld electronic device 1 and arranged near the backside wall 1A of the casing. Consequently, the tactile temperature near the backside wall 1A of the casing is not locally or intensively increased by the heat dissipation element.

In the first embodiment, the heat resistant layer 23 is formed on the outer side of the pipe body 21 of the heat pipe 2. Alternatively, the heat resistant layer 23 is formed on the inner side of the pipe body 21. FIGS. 3A-3E schematically illustrate some variant examples of the heat dissipation element of the first embodiment installed in the handheld electronic device. As mentioned above, the capillary structure 22 is disposed within the pipe body 21 of the heat pipe 2. Consequently, the forming sequences, the relative positions and the structures of the heat resistant layer 23 and the capillary structure 22 are diversified and not restricted. Please refer to FIG. 3A. After the capillary structure 22 is formed on the inner side of the pipe body 21 of the heat pipe 2, the heat resistant layer 23 is formed on the inner side of the capillary structure 22. That is, the heat pipe 2 is a three-layered structure that comprises the pipe body 21, the capillary structure 22 and the heat resistant layer 23 from outside to inside. Please refer to FIG. 3B. After the heat resistant layer 23 is formed on the inner side of the pipe body 21 of the heat pipe 2, the capillary structure 22 is formed on the inner side of the heat resistant layer 23. That is, the heat pipe 2 is a three-layered structure that comprises the pipe body 21, the heat resistant layer 23 and the capillary structure 22 from outside to inside. There are many types of capillary structures. For example, the capillary structure includes a sintered capillary structure, a recessed capillary structure, a mesh-type capillary structure or a fiber-type capillary structure. In case that the inner portion of the pipe body along the radial direction is not completely occupied by the capillary structure, the three-layered structure cannot be obviously defined by the pipe body, the capillary structure and the heat resistant layer. For example, as shown in FIG. 3C, a fiber bundle 22A is used as the capillary structure of the heat pipe 2, the heat resistant layer 23 is located beside the fiber bundle 22A, which is disposed within the pipe body 21 of the heat pipe 2. Moreover, the heat resistant layer 23 and the fiber bundle 22A are not overlapped with each other. Please refer to FIG. 3D. After the heat resistant layer 23 is formed on the inner side of the pipe body 21 of the heat pipe 2, the fiber bundle 22A is placed in the inner side of the heat resistant layer 23.

In an embodiment, the heat resistant layer and the capillary structure are two individual components structurally. Alternatively, the heat resistant layer and the capillary structure are combined as a single component, or the heat resistant layer and the capillary structure are formed as a structure with the functions of the two components. For example, a capillary structure with a low thermal conductivity to provide the function of the heat resistant layer or a heat resistant layer with a capillary structure is feasible. Please refer to FIG. 3E. After the heat resistant layer 23 is formed on the inner side of the pipe body 21 of the heat pipe 2, the heat resistant layer 23 is machined to create a recessed structure 22B on the surface of the heat resistant layer 23. Under this circumstance, the heat resistant layer not only has the heat resistant efficacy but also provides the structure and function of the capillary structure.

In the first embodiment, the heat resistant layer is located at the heat resistance section. It is noted that the position of the heat resistant layer is not restricted to the heat resistance section. The heat resistant layer may be located at the evaporation section of the heat pipe or located at the condensation section of the heat pipe as long as the normal heat absorbing efficacy of the evaporation section and the normal heat radiating efficacy of the condensation section are not adversely affected.

Please refer to FIGS. 4A and 4B. FIG. 4A is a schematic perspective view illustrating a heat dissipation element (e.g., a heat pipe) according to a second embodiment of the present invention and a handheld electronic device using the heat dissipation element. FIG. 4B is a schematic cross-sectional view illustrating the inner structure of the handheld electronic device of FIG. 4A and taken along the line 4B-4B. In this embodiment, the heat dissipation element is a heat pipe 2. The arrangement of the heat pipe 2 in the handheld electronic device 1 and the relationships between the heat pipe 2 and the adjacent electronic components 11, 12 are similar to those of the first embodiment, and are not redundantly described herein. In the heat pipe 2 of this embodiment, the heat resistant layer 23 is located at the evaporation section 21A or the condensation section 21B of the heat pipe 2.

In case that the heat is absorbed by a surface of the heat pipe in the evaporation section, a portion of the heat is radiated to the surroundings from another surface of the heat pipe and the tactile temperature of the casing of the handheld electronic device is increased or centralized. For solving this drawback, the heat pipe of the second embodiment is further improved. In this embodiment, the heat resistant layer is located at the evaporation section of the heat pipe. However, the heat resistant layer is formed on a specified site where the pipe body of the heat pipe is not in direct thermal contact with the heat generation element. Consequently, the normal heat absorbing efficacy of the heat pipe can be maintained. Please refer to FIGS. 4A and 4B. In this embodiment, the heat resistant layer 23 is formed on an outer side of the pipe body 21 of the heat pipe 2 corresponding to the evaporation section 21A. The heat pipe 2 has a far side away from the heat generation element 11, and the heat resistant layer 23 is located at the far side of the heat pipe 2. As shown in FIG. 4A, the heat pipe 2 is covered by the heat resistant layer 23 along a horizontal direction. For example, the far side of the heat pipe 2 is partially covered by the heat resistant layer 23, and the both ends of the heat pipe 2 are exposed. Alternatively, the far side of the pipe body 21 of the heat pipe 2 is completely covered by the heat resistant layer 23. That is, the both ends of the heat pipe 2 are also covered. As shown in FIG. 4B, the pipe body 21 is covered by the heat resistant layer 23 along a vertical direction. The far side of the heat pipe 2 is covered by the heat resistant layer 23 from the top surface of the heat pipe 2, but the heat resistant layer 23 is not extended to the bottom surface of the heat pipe 2. Consequently, the thermal contact between the heat pipe 2 and the heat generation element 11 is not affected. The above design has the following advantages. After the heat is absorbed by the heat pipe 2 in the evaporation section 21A, the possibility of directly transferring the heat to the casing of the handheld electronic device 1 (e.g., the backside wall 1A of the handheld electronic device 1) is reduced or minimized. Consequently, the tactile temperature of the casing of the handheld electronic device 1 corresponding to the evaporation section 21A of the heat pipe 2 is not largely increased or centralized.

In the second embodiment, the heat resistant layer 23 is formed on the outer side of the pipe body 21 of the heat pipe 2 corresponding to the evaporation section 21A. Alternatively, the heat resistant layer 23 is formed on an inner side of the pipe body 21 of the heat pipe 2 corresponding to the evaporation section 21A, and the heat resistant layer 23 is located at the far side of the heat pipe 2 away from the heat generation element 11. FIGS. 4C and 4D schematically illustrate some variant examples of the heat dissipation element (e.g., a heat pipe) of the second embodiment installed in the handheld electronic device. Please refer to FIG. 4C. After the capillary structure 22 is formed on the inner side of the pipe body 21 of the heat pipe 2, the heat resistant layer 23 is formed on the inner side of the capillary structure 22. Please refer to FIG. 4D. After the heat resistant layer 23 is formed on the inner side of the pipe body 21 of the heat pipe 2, the capillary structure 22 is formed on the inner side of the heat resistant layer 23 and the inner side of the pipe body 21. In the above two designs, the heat resistant layer 23 is located at the far side of the heat pipe 2 away from the heat generation element 11. Consequently, the normal heat absorbing efficacy of the heat pipe 2 can be maintained. The capillary structure 22 used in this embodiment is similar to that of the first embodiment. That is, the fiber bundle or the recessed capillary structure is suitably used as the capillary structure 22 of the second embodiment while the teachings about the heat resistant concept of the first embodiment are retained.

As mentioned above, the heat resistant layer 23 is located at the evaporation section 21A of the heat pipe 2. In another design, the heat resistant layer 23 is located at the condensation section 21B of the heat pipe 2. The region covered by the heat resistant layer 23 or the way of forming the heat resistant layer 23 on the inner side or the outer side of the heat pipe 2 is similar to that of forming the heat resistant layer 23 on the evaporation section 21A of the heat pipe 2. That is, the heat pipe 2 in the condensation section is partially or completely covered by the heat resistant layer 23 along the horizontal direction. Similarly, the region covered by the heat resistant layer 23 along the vertical position is a specified site where the heat pipe is not in direct thermal contact with the heat sink 3 in the condensation section 21B. Consequently, the normal heat radiating efficacy of the heat pipe 2 can be maintained. In case that the evaporation section 21A, the heat resistant section 21C and the condensation section 21B of the heat pipe 2 near the casing of the handheld electronic device 1 are all covered by the heat resistant layer 23, the possibility of transferring the heat to the casing of the handheld electronic device 1 is largely reduced. Consequently, the tactile temperature of the casing of the handheld electronic device 1 is controlled to be in a more suitable range.

The concepts of the present invention can be also applied to other heat dissipation element such as a loop-type heat pipe or a vapor chamber. Please refer to FIGS. 5A and 5B. FIG. 5A is a schematic perspective view illustrating a heat dissipation element (e.g., a loop-type heat pipe) according to a third embodiment of the present invention and a handheld electronic device using the heat dissipation element. FIG. 5B is a schematic cross-sectional view illustrating the inner structure of the handheld electronic device of FIG. 5A and taken along the line 5B-5B.

In this embodiment, the heat dissipation element is a loop-type heat pipe 4. The operating principles of the loop-type heat pipe are similar to those of the heat pipe. In comparison with the appearance of the heat pipe, the working medium in the loop-type heat pipe is continuously circulated within a closed loop along a single direction. In this embodiment, the loop-type heat pipe 4 comprises an evaporation section 4A, a vapor channel 4B, a condensation section 4C and a liquid channel 4D. In the heat resistant mechanism of the loop-type heat pipe 4, the heat resistant layer 41 is formed on an outer side or an inner side of the vapor channel 4B. As shown in FIGS. 5A and 5B, the heat resistant layer 41 is arranged around the vapor channel 4B. Consequently, while the heat is transferred to the condensation section 41C, the heat is not released to the surroundings to influence the electronic component 12 of the handheld electronic device 1 near the vapor channel 4B, or the heat is not externally released to the casing of the handheld electronic device 1 to influence the tactile temperature. Like the first embodiment and the second embodiment, the heat resistant layer is formed on the inner side of the vapor channel 4B of the loop-type heat pipe 4 of the third embodiment.

As mentioned above in the third embodiment, the heat resistant layer is formed on the outer side or the inner side of the vapor channel of the loop-type heat pipe. In another design, the heat resistant layer is arranged around the evaporation section, the condensation section or even the liquid channel of the loop-type heat pipe as long as the normal heat absorbing efficacy of the evaporation section and the normal heat radiating efficacy of the condensation section are not adversely affected.

Please refer to FIGS. 6A and 6B. FIG. 6A is a schematic perspective view illustrating a heat dissipation element (e.g., a loop-type heat pipe) according to a fourth embodiment of the present invention and a handheld electronic device using the heat dissipation element. FIG. 6B is a schematic cross-sectional view illustrating the inner structure of the handheld electronic device of FIG. 6A and taken along the line 6B-6B. In case that the heat is absorbed by a surface of the loop-type heat pipe in the evaporation section, a portion of the heat is radiated to the surroundings from another surface of the loop-type heat pipe and the tactile temperature of the casing of the handheld electronic device is increased or centralized. For solving this drawback, the loop-type heat pipe of the fourth embodiment is further improved. In this embodiment, the heat resistant layer is located at the evaporation section of the loop-type heat pipe. However, the heat resistant layer is formed on a specified site where the pipe body of the loop-type heat pipe is not in direct thermal contact with the heat generation element. Consequently, the normal heat absorbing efficacy of the loop-type heat pipe can be maintained. Please refer to FIGS. 6A and 6B. In this embodiment, the heat resistant layer 41 is formed on an outer side of the loop-type heat pipe 4 corresponding to the evaporation section 4A. The loop-type heat pipe 4 has a far side away from the heat generation element 11, and the heat resistant layer 41 is located at the far side of the loop-type heat pipe 4. As shown in FIG. 6A, the loop-type heat pipe 4 is covered by the heat resistant layer 41 along a horizontal direction. For example, the far side of the loop-type heat pipe 4 is partially or completely covered by the heat resistant layer 41 as long as the normal heat absorbing efficacy of the evaporation section is not adversely affected. The above design has the following advantages. After the heat is absorbed by the loop-type heat pipe 4 in the evaporation section 4A, the possibility of directly transferring the heat to the casing of the handheld electronic device 1 (e.g., the backside wall 1A of the handheld electronic device 1) is reduced or minimized. Consequently, the tactile temperature of the casing of the handheld electronic device 1 corresponding to the evaporation section 4A of the loop-type heat pipe 4 is not largely increased or centralized.

As mentioned above, the heat resistant layer 41 is located at the evaporation section 4A of the loop-type heat pipe 4. In another design, the heat resistant layer 41 is located at the condensation section 4C of the loop-type heat pipe 4. The loop-type heat pipe 4 in the condensation section 4C is partially or completely covered by the heat resistant layer along the horizontal direction. Similarly, the region covered by the heat resistant layer is a specified site where the condensation section is not in direct thermal contact with other heat dissipation element (e.g., the heat sink 3). Consequently, the normal heat radiating efficacy of the loop-type heat pipe 4 can be maintained. In case that the evaporation section 4A, the vapor channel 4B, the condensation section 4C and the liquid channel 4D of the loop-type heat pipe 4 near the casing of the handheld electronic device 1 are all covered by the heat resistant layer 41, the possibility of transferring the heat to the casing of the handheld electronic device 1 is largely reduced. Consequently, the tactile temperature of the casing of the handheld electronic device 1 is controlled to be in a more suitable range.

In the third embodiment and the fourth embodiment, an additional heat resistant mechanism is installed on the loop-type heat pipe. The present invention further provides a loop-type heat pipe with a heat resistant mechanism. Please refer to FIGS. 7A and 7B. FIG. 7A is a schematic perspective view illustrating a heat dissipation element (e.g., a loop-type heat pipe) according to a fifth embodiment of the present invention and a handheld electronic device using the heat dissipation element. FIG. 7B is a schematic cross-sectional view illustrating the inner structure of the handheld electronic device of FIG. 7A and taken along the line 7B-7B. In case that the heat is absorbed by a surface of the loop-type heat pipe in the evaporation section, a portion of the heat is radiated to the surroundings from another surface of the loop-type heat pipe and the tactile temperature of the casing of the handheld electronic device is increased or centralized. For solving this drawback, the loop-type heat pipe of the fifth embodiment is further improved. In this embodiment, the loop-type heat pipe 4 comprises a top plate 42 and a bottom plate 43. The thermal conductivity of the bottom plate 43 is higher than the thermal conductivity of the top plate 42, or the top plate 42 is made of a material with a lower thermal conductivity. In this embodiment, the bottom plate 43 is in direct contact with the heat generation element 11. After the heat of the heat generation element 11 is absorbed by the bottom plate in the evaporation section 4A, the heat is not easily transferred to the casing of the handheld electronic device 1 (e.g., the backside wall 1A of the handheld electronic device 1) through the top plate 42 because the thermal conductivity of the top plate 42 is lower. Consequently, the tactile temperature of the casing of the handheld electronic device 1 near the evaporation section is controlled to be in a more suitable range. Moreover, the top plate 42 with the lower thermal conductivity is also located at the vapor channel 4B and the condensation section 4C of the loop-type heat pipe 4. Since the heat is not easily transferred to the casing of the handheld electronic device 1 (e.g., the backside wall 1A of the handheld electronic device 1) through the top plate 42, the tactile temperature of the casing of the handheld electronic device 1 near the vapor channel 4B and the condensation section 4C is controlled to be in a more suitable range. Moreover, the condensation section 4C of the loop-type heat pipe 4 is still able to dissipate heat normally. For example, the heat is transferred along the horizontal direction or the heat is further dissipated by another heat dissipation mechanism (e.g., the underlying heat sink 3).

As shown in FIGS. 7A and 7B, the top plate 42 and the bottom plate 43 are stacked on each other to define the evaporation section, the vapor channel, the condensation section and the liquid channel of the loop-type heat pipe. FIG. 7C schematically illustrates a variant example of the heat dissipation element (e.g., a loop-type heat pipe) of the fifth embodiment installed in the handheld electronic device. As shown in FIG. 7C, the evaporation section 4A of the loop-type heat pipe 4 is a combination of a top plate 4A1 and a bottom plate 4A2, or the condensation section 4C of the loop-type heat pipe 4 is a combination of a top plate 4C1 and a bottom plate 4C2. The vapor channel 4B between the evaporation section 4A and the condensation section 4C and the liquid channel 4D between the condensation section 4C and the evaporation section 4A are not divided into two layers. That is, the vapor channel 4B and the liquid channel 4D are tubes that are made of the same material. Since the bottom plate 4A2 in the evaporation section 4A is in contact with the heat generation element 11, the thermal conductivity of the bottom plate 4A2 is higher than the thermal conductivity of the top plate 4A1, or the thermal conductivity of the bottom plate 4A2 is higher than the thermal conductivity of the vapor channel 4B. In this embodiment, the bottom plate 4A2 is in direct contact with the heat generation element 11. After the heat of the heat generation element 11 is absorbed by the bottom plate 4A2 in the evaporation section 4A, the heat is not easily transferred to the casing of the handheld electronic device 1 (e.g., the backside wall 1A of the handheld electronic device 1) through the top plate 4A1 or the vapor channel 4B because the thermal conductivity of the top plate 4A1 is lower or the thermal conductivity of the vapor channel 4B is lower. As mentioned above, the condensation section 4C of the loop-type heat pipe 4 is a combination of the top plate 4C1 and the bottom plate 4C2. Similarly, the thermal conductivity of the bottom plate 4C2 is higher than the thermal conductivity of the top plate 4C1, or the thermal conductivity of the bottom plate 4CA2 is higher than the thermal conductivity of the liquid channel 4D. Since the heat is not easily transferred to the casing of the handheld electronic device 1 (e.g., the backside wall 1A of the handheld electronic device 1) through the top plate 4C1 or the liquid channel 4D, the heat resistant efficacy is enhanced.

In addition to the heat pipe and the loop-type heat pipe, the heat resistant mechanism is applied to a vapor chamber and installed in the handheld electronic device. FIG. 8A is a schematic perspective view illustrating a heat dissipation element (e.g., a vapor chamber) according to a sixth embodiment of the present invention and a handheld electronic device using the heat dissipation element. FIG. 8B is a schematic cross-sectional view illustrating the inner structure of the handheld electronic device of FIG. 8A and taken along the line 8B-8B. FIGS. 8C and 8D schematically illustrate some variant examples of the heat dissipation element (e.g., a vapor chamber) of the sixth embodiment installed in the handheld electronic device.

The operating principles of the vapor chamber 5 are similar to those of the heat pipe. The heat pipe is used for transferring heat linearly along a one-dimensional direction. Whereas, the vapor chamber 5 is used for transferring heat along a two-dimensional direction. In this embodiment, the vapor chamber 5 comprises a top thin plate 51 and a bottom thin plate 52. The bottom thin plate 52 is in contact with the heat generation element 11. The heat resistant mechanism for the vapor chamber 5 of the present invention has various types. In the example of FIG. 8B, the vapor chamber 5 is a combination of the top thin plate 51 and the bottom thin plate 52. The thermal conductivity of the bottom thin plate 52 is higher than the thermal conductivity of the top thin plate 51, or the top thin plate 51 is made of a material with a lower thermal conductivity. Consequently, while the heat is transferred and released, the heat is not centralized to the top thin plate 51 of the vapor chamber 5 or the center of the top thin plate 51. That is, the heat can be transferred along the horizontal direction more uniformly. Due to the heat resistant mechanism of the present invention, the ambient temperature outside the top thin plate 51 or the tactile temperature of the casing of the handheld electronic device near the top thin plate 51 (e.g., the backside wall 1A of the handheld electronic device 1) is improved or controlled. As mentioned above, the thermal conductivity of the top thin plate and the thermal conductivity of the bottom thin plate are different. Moreover, the above heat resistant mechanisms of the heat pipe and the loop-type heat pipe may be applied to the vapor chamber. As shown in FIG. 8C, the vapor chamber 5 is a combination of the top thin plate 51 and the bottom thin plate 52. Moreover, a heat resistant layer 53 is formed on an outer side of the top thin plate 51 and arranged near the casing of the handheld electronic device 1. As shown in FIG. 8D, the heat resistant layer 53 is disposed within the vapor chamber 5 and formed on an inner side of the top thin plate 51. Consequently, while the heat is transferred and released, the heat is not transferred to the casing of the handheld electronic device 1. Consequently, the tactile temperature is controlled to be in a more suitable range

In accordance with the present invention, the heat resistant layer is made of a material with low thermal conductivity. For example, the heat resistant layer is made of aluminum, glass fiber, ceramic, rubber, asbestos, rock wool, aerogel, stainless steel, ceramic paint, aerogel paint, insulation resin paint or silicate paint. The way of forming the heat resistant layer is not restricted. For example, the heat resistant layer is produced by a coating process, a sputtering process, a deposition process, a sintering process, an etching process, an anodizing process, an electroplating process, an electroless plating process or an attaching process. Alternatively, the heat resistant layer is firstly formed as a hollow tube, and then the hollow tube is sheathed around the heat pipe.

The heat dissipation element and the heat generation component within the handheld electronic component are in thermal contact with each other. The structure of the thermal contact includes a direction contact mechanism or an indirect contact mechanism. In some embodiments, a thermal grease, a heat dissipation plate or a heat conduction block is arranged between the heat dissipation element and the heat generation element.

In the above embodiments and associated drawings, the relative positions between the casing of the handheld electronic device and the heat dissipation element and the installation of the heat dissipation element in the handheld electronic device are not restricted. It is noted that the heat resistant mechanism of the present invention may be applied to an electronic product and modified according to practical requirements. For example, in case that the installation position of the heat dissipation element is at the edge frame near the two lateral walls 1B, the tactile temperature of the two lateral walls of the handheld electronic device is not very high. Similarly, the technology of the present invention can be employed to reduce the tactile temperature of the top edge frame, the bottom edge frame or the front wall 1C (e.g., the display screen) of the handheld electronic device.

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 embodiments. 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 modifications and similar structures.

Claims

1. A heat pipe, comprising:

a pipe body comprising an evaporation section, a heat resistant section and a condensation section, wherein the heat resistant section is arranged between the evaporation section and the condensation section;

a capillary structure disposed within the pipe body; and

a heat resistant layer disposed within the pipe body and located at the heat resistant section.

2. The heat pipe according to claim 1, wherein the capillary structure is arranged between the pipe body and the heat resistant layer.

3. The heat pipe according to claim 1, wherein the capillary structure is a fiber bundle.

4. The heat pipe according to claim 1, wherein the capillary structure is a fiber bundle, wherein the heat resistant layer is located beside the fiber bundle, and the heat resistant layer and the fiber bundle are not overlapped with each other.

5. A heat pipe in contact with a heat generation element, the heat pipe comprising:

a pipe body comprising an evaporation section and a condensation section;

a capillary structure disposed within the pipe body; and

a heat resistant layer disposed within the pipe body, wherein the pipe body has a far side away from the heat generation element, and the heat resistant layer is located at the far side of the pipe body.

6. The heat pipe according to claim 5, wherein the heat resistant layer is formed on an inner side of the capillary structure.

7. The heat pipe according to claim 5, wherein the heat resistant layer is located at the evaporation section or the condensation section of the pipe body.

8. A loop-type heat pipe in contact with a heat generation element, the loop-type heat pipe comprising:

a top plate; and

a bottom plate in contact with the heat generation element, wherein the top plate and the bottom plate are stacked on each other to define an evaporation section, a vapor channel, a condensation section and a liquid channel, wherein a thermal conductivity of the bottom plate is higher than a thermal conductivity of the top plate.

9. A loop-type heat pipe in contact with a heat generation element, the loop-type heat pipe comprising:

a top plate;

a bottom plate in contact with the heat generation element, wherein the top plate and the bottom plate are stacked on each other to define an evaporation section and a condensation section, wherein a thermal conductivity of the bottom plate is higher than a thermal conductivity of the top plate;

a vapor channel connected with the evaporation section and the condensation section; and

a liquid channel connected with the condensation section and the evaporation section.

10. A vapor chamber in contact with a heat generation element, the vapor chamber comprising:

a top thin plate; and

a bottom thin plate in contact with the heat generation element, wherein a thermal conductivity of the bottom thin plate is higher than a thermal conductivity of the top thin plate.

11. A vapor chamber in contact with a heat generation element, the vapor chamber comprising:

a top thin plate; and

a bottom thin plate in contact with the heat generation element; and

a heat resistant layer formed on an inner side of the top thin plate.