Heat Diffusion Device

Abstract

A vapor chamber 1 that is one embodiment of this thermal diffusion device comprises: a housing 10 that has a first inner wall surface 11a and a second inner wall surface 12a facing one other in the thickness direction Z; a working medium 20 that is enclosed in an internal space of the housing 10; and a sheet-like wick 30 that is disposed in said internal space of the housing 10. The wick 30 has a bend section 35 provided as a result of the wick 30 protruding from the first inner wall surface 11a toward the second inner wall surface 12a. A liquid flow passage 40 for the working medium 20 is formed in a space surrounded by the first inner wall surface 11a and the bend section 35 of the wick 30.

Description

[Technical field]

[0001] The present invention relates to a heat spreading device. [Background technology]

[0002] In recent years, the amount of heat generated has increased due to the high integration and high performance of elements. In addition, as products become smaller, the heat density increases, making heat dissipation measures important. This situation is particularly noticeable in the field of mobile terminals such as smartphones and tablets. Graphite sheets are often used as heat countermeasures, but since their heat transport capacity is insufficient, the use of various heat countermeasures is being considered. In particular, the use of vapor chambers, which are planar heat pipes, is being considered as a heat diffusion device that can diffuse heat very effectively.

[0003] The vapor chamber has a structure in which a working medium (also called working fluid) and a wick that transports the working medium by capillary force are enclosed inside a housing. The working medium absorbs heat from a heat generating element such as an electronic component in an evaporation section that absorbs heat from the heat generating element and evaporates in the vapor chamber, then moves inside the vapor chamber, is cooled, and returns to a liquid phase. The working medium that has returned to a liquid phase moves again to the evaporation section on the heat generating element side by the capillary force of the wick, and cools the heat generating element. By repeating this process, the vapor chamber operates autonomously without an external power source, and can diffuse heat two-dimensionally at high speed by utilizing the latent heat of evaporation and latent heat of condensation of the working medium.

[0004] In order to accommodate the trend toward thinner mobile devices such as smartphones and tablets, vapor chambers must also be made thinner, but it is difficult to ensure the mechanical strength and heat transport efficiency of such thin vapor chambers.

[0005] Therefore, as described in Patent Document 1, it has been proposed to provide a support part inside the housing in order to maintain the internal space of the housing that constitutes the vapor chamber.

[0006] Patent Document 1 discloses a vapor chamber comprising a container having a cavity formed by one plate-shaped body to which a heating element is thermally connected and another plate-shaped body opposite the one plate-shaped body, a working fluid sealed in the cavity, and a wick structure separate from the container and contained in the cavity, wherein the container has a support part protruding from the inner surface of the other plate-shaped body toward the one plate-shaped body by providing a recess in the outer surface of the other plate-shaped body, and the angle formed between the support part at the base part of the support part rising from the inner surface of the other plate-shaped body and the inner surface of the other plate is an obtuse angle. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-76355 Summary of the Invention [Problem to be solved by the invention]

[0008] In the vapor chamber described in Patent Document 1, the sum of the height of the support part and the thickness of the wick structure corresponds to the thickness of the internal space, so the vapor chamber can be made thinner by adjusting the height of the support part and the thickness of the wick structure. However, there is room for improvement in terms of increasing the heat dissipation efficiency of the vapor chamber.

[0009] The above problem is not limited to vapor chambers, but is a problem common to heat diffusion devices that are capable of diffusing heat using a similar structure to a vapor chamber.

[0010] The present invention has been made to solve the above problems, and has an object to provide a heat spreading device with high heat dissipation efficiency. It is also an object of the present invention to provide an electronic device equipped with the heat spreading device. [Means for solving the problem]

[0011] The heat diffusion device of the present invention includes a housing having a first inner wall surface and a second inner wall surface opposed to each other in a thickness direction, a working medium sealed in an internal space of the housing, and a sheet-like wick disposed in the internal space of the housing. The wick has a curved portion protruding from the first inner wall surface toward the second inner wall surface. A liquid flow path for the working medium is formed in a space surrounded by the curved portion of the wick and the first inner wall surface.

[0012] An electronic device of the present invention includes the heat spreading device of the present invention. Effect of the Invention

[0013] According to the present invention, it is possible to provide a heat spreading device having high heat dissipation efficiency, and further, it is possible to provide an electronic device including the heat spreading device. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing a schematic example of a heat spreading device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view showing an example of the internal structure of the heat spreading device according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is an example of a cross-sectional view of the heat spreading device shown in FIG. 2 taken along line AA. [Figure 4] FIG. 4 is another example of a cross-sectional view of the heat spreading device shown in FIG. 2 taken along line AA. [Diagram 5] FIG. 5 is a plan view showing a schematic example of an internal structure of a heat spreading device according to the second embodiment of the present invention. [Figure 6] FIG. 6 is an example of a cross-sectional view of the heat spreading device shown in FIG. 5 taken along line AA. [Figure 7] FIG. 7 is a plan view showing a schematic example of an internal structure of a heat spreading device according to a third embodiment of the present invention. [Figure 8] FIG. 8 is an example of a cross-sectional view of the heat spreading device shown in FIG. 7 taken along line AA. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The heat spreading device of the present invention will now be described. However, the present invention is not limited to the following embodiments, and can be modified and applied as appropriate within the scope of the present invention. Note that the present invention also includes a combination of two or more of the individual preferred configurations of the present invention described below.

[0016] In the heat diffusion device of the present invention, a sheet-like wick is disposed in the internal space of the housing, so the size of the gas-liquid exchange surface is not limited as compared to the case where a linear wick is disposed.

[0017] The sheet-like wick has a curved portion that protrudes from the first inner wall surface of the housing toward the second inner wall surface, and a liquid flow path for the working medium is formed in the space surrounded by the curved portion of the wick and the first inner wall surface. Therefore, not only can the capillary force be exerted by the wick located around the liquid flow path, but the liquid resistance passing through the liquid flow path is reduced, allowing the working medium to move smoothly through the liquid flow path. As a result, the transmittance can be made higher than that of the wick alone.

[0018] As described above, in the heat spreading device of the present invention, the maximum heat transport amount is increased, and therefore the heat dissipation efficiency can be improved.

[0019] The following embodiments are merely examples, and it goes without saying that partial replacement or combination of the configurations shown in the different embodiments is possible. From the second embodiment onwards, the description of the matters common to the first embodiment will be omitted, and only the differences will be described. In particular, the same effects and advantages due to the same configuration will not be mentioned in each embodiment.

[0020] In the following description, unless there is a need to distinguish between the various embodiments, they will simply be referred to as the "heat spreading device of the present invention."

[0021] In the following, a vapor chamber will be described as an example of an embodiment of the heat spreading device of the present invention, but the heat spreading device of the present invention can also be applied to heat spreading devices such as heat pipes.

[0022] The drawings shown below are schematic, and the dimensions and aspect ratios may differ from the actual products.

[0023] In this specification, terms indicating the relationship between elements (e.g., "vertical," "parallel," "orthogonal," etc.) and terms indicating the shapes of elements are not intended to be used in a strict sense, but are intended to include a range of substantial equivalence, for example, a difference of a few percent.

[0024] [First embodiment] In the heat spreading device according to the first embodiment of the present invention, the curved portions of the wick are arranged in two or more rows so as to be parallel to each other, and these curved portions are arranged so as to converge at the evaporation portion.

[0025] Fig. 1 is a perspective view showing an example of a heat spreading device according to a first embodiment of the present invention. Fig. 2 is a plan view showing an example of an internal structure of the heat spreading device according to the first embodiment of the present invention. Fig. 3 is a cross-sectional view taken along line AA of the heat spreading device shown in Fig. 2.

[0026] The vapor chamber (heat diffusion device) 1 shown in Fig. 1 includes a hollow housing 10 that is sealed in an airtight state. The housing 10 has a first inner wall surface 11a and a second inner wall surface 12a that face each other in a thickness direction Z, as shown in Fig. 3. The vapor chamber 1 further includes a working medium 20 sealed in the internal space of the housing 10, and a wick 30 disposed in the internal space of the housing 10.

[0027] As shown in FIG. 2, the housing 10 is provided with an evaporation portion EP that evaporates the enclosed working medium 20 (see FIG. 3). As shown in FIG. 1, a heat source HS, which is a heat generating element, is disposed on the outer wall surface of the housing 10. Examples of the heat source HS include electronic components of an electronic device, such as a central processing unit (CPU). Of the internal space of the housing 10, a portion that is adjacent to the heat source HS and that is heated by the heat source HS corresponds to the evaporation portion EP.

[0028] The vapor chamber 1 is preferably planar as a whole. That is, the housing 10 is preferably planar as a whole. Here, "planar" includes plate-like and sheet-like shapes, and means a shape in which the dimension in the width direction X (hereinafter referred to as width) and the dimension in the length direction Y (hereinafter referred to as length) are considerably larger than the dimension in the thickness direction Z (hereinafter referred to as thickness or height), for example, a shape in which the width and length are 10 times or more, preferably 100 times or more, of the thickness.

[0029] The size of the vapor chamber 1, i.e., the size of the housing 10, is not particularly limited. The width and length of the vapor chamber 1 can be appropriately set depending on the application. The width and length of the vapor chamber 1 are, for example, 5 mm or more and 500 mm or less, 20 mm or more and 300 mm or less, or 50 mm or more and 200 mm or less. The width and length of the vapor chamber 1 may be the same or different.

[0030] Housing 10 is preferably constructed from opposing first and second sheets 11 and 12 whose outer edges are joined together.

[0031] When the housing 10 is composed of the first sheet 11 and the second sheet 12, the material constituting the first sheet 11 and the second sheet 12 is not particularly limited as long as it has properties suitable for use as a vapor chamber, such as thermal conductivity, strength, flexibility, and the like. The material constituting the first sheet 11 and the second sheet 12 is preferably a metal, such as copper, nickel, aluminum, magnesium, titanium, iron, or an alloy containing these as a main component, and is particularly preferably copper. The materials constituting the first sheet 11 and the second sheet 12 may be the same or different, but are preferably the same.

[0032] When the housing 10 is composed of the first sheet 11 and the second sheet 12, the first sheet 11 and the second sheet 12 are joined to each other at their outer edges. The method of such joining is not particularly limited, but for example, laser welding, resistance welding, diffusion bonding, brazing, TIG welding (tungsten-inert gas welding), ultrasonic bonding, or resin sealing can be used, and preferably laser welding, resistance welding, or brazing can be used.

[0033] The thickness of the first sheet 11 and the second sheet 12 is not particularly limited, but is preferably 10 μm or more and 200 μm or less, more preferably 30 μm or more and 100 μm or less, and further preferably 40 μm or more and 60 μm or less. The thickness of the first sheet 11 and the second sheet 12 may be the same or different. Furthermore, the thickness of each of the first sheet 11 and the second sheet 12 may be the same throughout, or may be thin in some parts.

[0034] There are no particular limitations on the shapes of the first sheet 11 and the second sheet 12. For example, the first sheet 11 and the second sheet 12 may each have a shape in which the outer edge portion is thicker than the portion other than the outer edge portion.

[0035] The thickness of the entire vapor chamber 1 is not particularly limited, but is preferably 50 μm or more and 500 μm or less.

[0036] The planar shape of the housing 10 as viewed from the thickness direction Z is not particularly limited, and examples thereof include polygons such as triangles or rectangles, circles, ellipses, and shapes that are combinations of these. The planar shape of the housing 10 may be an L-shape, a C-shape, a stepped shape, or the like. The housing 10 may have a through hole. The planar shape of the housing 10 may be a shape that corresponds to the use of the vapor chamber, the shape of the location where the vapor chamber is incorporated, and other parts that exist in the vicinity.

[0037] The working medium 20 is not particularly limited as long as it can undergo a gas-liquid phase change in the environment inside the housing 10, and for example, water, alcohols, alternative fluorocarbons, etc. can be used. For example, the working medium 20 is an aqueous compound, and is preferably water.

[0038] 2 and 3, the wick 30 is generally sheet-like. Here, "sheet-like" refers to a shape in which the width and length are significantly larger than the thickness, for example, the width and length are 10 times or more, preferably 100 times or more, the thickness.

[0039] The wick 30 has a capillary structure that can move the working medium 20 by capillary force. The capillary structure of the wick 30 may be a known structure used in conventional vapor chambers. Examples of the capillary structure include a microstructure having irregularities such as pores, grooves, and protrusions, such as a porous structure, a fibrous structure, a groove structure, and a mesh structure.

[0040] The material of the wick 30 is not particularly limited, and may be, for example, a metal porous membrane, mesh, nonwoven fabric, sintered body, or porous body formed by etching or metal processing. The mesh that is the material of the wick 30 may be, for example, a metal mesh, a resin mesh, or a surface-coated version of these meshes, and is preferably made of a copper mesh, a stainless steel (SUS) mesh, or a polyester mesh. The sintered body that is the material of the wick 30 may be, for example, a metal porous sintered body, a ceramic porous sintered body, or the like, and is preferably made of a copper or nickel porous sintered body. The porous body that is the material of the wick 30 may be, for example, a metal porous body, a ceramic porous body, a resin porous body, or the like.

[0041] The thickness of the wick 30 is not particularly limited, but is, for example, 2 μm to 200 μm, preferably 5 μm to 100 μm, and more preferably 10 μm to 40 μm. The thickness of the wick 30 may vary in parts, but is preferably constant.

[0042] The size and shape of the wick 30 are not particularly limited, but for example, it is preferable that the wick 30 is arranged continuously in the internal space of the housing 10. In the example shown in Figures 2 and 3, the wick 30 is arranged throughout the entire internal space of the housing 10, but the wick 30 may not be arranged in a part of the internal space of the housing 10. For example, in Figures 2 and 3, the wick 30 is in contact with the outer periphery of the internal space of the housing 10, but the wick 30 may not be in contact with the outer periphery of the internal space of the housing 10.

[0043] As shown in Fig. 3, the wick 30 is disposed along the first inner wall surface 11a of the housing 10. The wick 30 has a curved portion 35 that protrudes from the first inner wall surface 11a toward the second inner wall surface 12a. A liquid flow path 40 for the working medium 20 is formed in a space surrounded by the curved portion 35 of the wick 30 and the first inner wall surface 11a. Meanwhile, a vapor flow path 50 for the working medium 20 is formed in a gap other than the liquid flow path 40 in the housing 10.

[0044] As shown in FIGS. 2 and 3, the curved portion 35 of the wick 30 extends in the longitudinal direction of the housing 10 (lengthwise direction Y in FIGS. 2 and 3) when viewed in a plan view from the thickness direction Z.

[0045] In the example shown in Figs. 2 and 3, two or more rows of curved portions 35 are arranged parallel to each other, but a single row of curved portions 35 may be arranged.

[0046] When two or more rows of curved portions 35 are arranged, these curved portions 35 may be arranged so as to converge to the evaporation section EP, as shown in Fig. 2. That is, at least one row of curved portions 35 may have at least one bent portion in a plan view from the thickness direction Z so as to converge to the evaporation section EP. By concentrating the curved portions 35 at the evaporation section EP, it is possible to circulate the working medium 20 over a short distance.

[0047] In a cross-sectional view perpendicular to the extension direction of the curved portion 35, the width of the curved portion 35 is not particularly limited, but is, for example, 10 μm or more and 1000 μm or less. The width of the curved portion 35 corresponds to the width of the liquid flow path 40. The width of the curved portion 35 may or may not be constant in the thickness direction Z. Note that, when the width of the curved portion 35 varies in the thickness direction Z, the width of the widest part is defined as the width of the curved portion 35.

[0048] In a cross-sectional view perpendicular to the stretching direction of the curved portion 35, the height of the curved portion 35 is not particularly limited, but is, for example, 10 μm or more and 100 μm or less. The height of the curved portion 35 corresponds to the height of the liquid flow path 40. The height of the curved portion 35 may or may not be constant in the width direction X and the length direction Y. When the height of the curved portion 35 differs in the width direction X and the length direction Y, the height of the highest part is defined as the height of the curved portion 35.

[0049] As shown in Figures 2 and 3, it is preferable that a support 60 is disposed in the internal space of the housing 10 in contact with the second inner wall surface 12a. The support 60 is disposed in the vapor flow path 50. The vapor flow path 50 is divided between the support 60. By disposing the support 60 in the internal space of the housing 10, it is possible to support the housing 10. It is also possible to support the wick 30 by pressing the wick 30 with the support 60.

[0050] When the support 60 is disposed in the internal space of the housing 10, it is preferable that the curved portion 35 of the wick 30 is disposed in an area that is not sandwiched between the support 60 and the first inner wall surface 11a, as shown in Figures 2 and 3. In other words, it is preferable that the curved portion 35 of the wick 30 is not disposed between the support 60 and the first inner wall surface 11a in the thickness direction Z. By disposing the curved portion 35 that forms the liquid flow path 40 between the support 60, it is possible to increase the maximum heat transport amount without increasing the thickness of the vapor chamber 1 as a whole.

[0051] When two or more rows of curved portions 35 are arranged in an area not sandwiched between the support pillars 60 and the first inner wall surface 11a, the numbers of curved portions 35 arranged between the support pillars 60 may be the same or different.

[0052] The support 60 may be in contact with the wick 30 or may be fixed to the wick 30. When the support 60 is fixed to the wick 30, the vapor chamber 1 can be easily assembled. For example, when the wick 30 and the support 60 are made of metal, the wick 30 may be bonded to the support 60. The bonding method is not particularly limited, but for example, diffusion bonding or the like can be used. The wick 30 may also be bonded to the support 60 via a silica film or the like.

[0053] The support columns 60 may be disposed throughout the entire steam flow path 50, or the support columns 60 may not be disposed in some parts of the steam flow path 50.

[0054] The material for forming the support 60 is not particularly limited, but examples thereof include resin, metal, ceramics, or a mixture or laminate thereof. The support 60 may be integral with the housing 10, or may be formed, for example, by etching the inner wall surface of the housing 10.

[0055] The shape of the support 60 is not particularly limited as long as it can support the housing 10 and the wick 30, but examples of the cross-sectional shape perpendicular to the height direction of the support 60 include polygons such as rectangles, circles, and ellipses.

[0056] The height of the support pillars 60 may be the same or different in one vapor chamber.

[0057] 3, the width of the support 60 is not particularly limited as long as it provides a strength capable of suppressing deformation of the casing 10, but the circle-equivalent diameter of the cross section perpendicular to the height direction of the end of the support 60 is, for example, 100 μm to 2000 μm, and preferably 300 μm to 1000 μm. By increasing the circle-equivalent diameter of the support 60, deformation of the casing 10 can be further suppressed. On the other hand, by decreasing the circle-equivalent diameter of the support 60, a larger space can be secured for the movement of the vapor of the working medium 20.

[0058] The arrangement of the pillars 60 is not particularly limited, but is preferably arranged evenly in a predetermined region, more preferably evenly throughout, for example, so that the distance between the pillars 60 is constant. By arranging the pillars 60 evenly, it is possible to ensure uniform strength throughout the vapor chamber 1.

[0059] The curved portion 35 of the wick 30 that forms the liquid flow path 40 has a shape obtained by bending the wick 30. The curved portion 35 of the wick 30 can be formed, for example, by subjecting the wick 30 to a shaping process. The cross-sectional shape of the curved portion 35 perpendicular to the stretching direction is not particularly limited, and for example, in the vapor chamber 1 shown in FIG. 3, the cross-sectional shape of the curved portion 35 perpendicular to the stretching direction is a quadrangle such as a rectangle. When two or more rows of curved portions 35 are arranged, the cross-sectional shapes of the curved portions 35 may be the same or different.

[0060] FIG. 4 is another example of a cross-sectional view of the heat spreading device shown in FIG. 2 taken along line AA.

[0061] In the vapor chamber (thermal diffusion device) 1A shown in FIG. 4, the cross-sectional shape of the curved portion 35 perpendicular to the stretching direction is semicircular.

[0062] 4, the cross-sectional shape of the curved portion 35 perpendicular to the stretching direction may be semicircular or semi-elliptical, or may be polygonal such as triangular. The corners of the polygon may be rounded. If the cross-sectional shape of the curved portion 35 is rounded, the liquid resistance passing through the liquid flow path 40 can be reduced.

[0063] [Second embodiment] In a heat spreading device according to a second embodiment of the present invention, the curved portion of the wick extends in only one direction.

[0064] In the second embodiment of the present invention, the tool and process for forming the curved portion of the wick are simpler than those in the first embodiment of the present invention, and therefore the yield of the heat spreading device can be increased.

[0065] Fig. 5 is a plan view showing an example of the internal structure of the heat spreading device according to the second embodiment of the present invention, Fig. 6 is an example of a cross-sectional view taken along line AA of the heat spreading device shown in Fig. 5.

[0066] In the vapor chamber (thermal diffusion device) 2 shown in Figures 5 and 6, the curved portion 35 of the wick 30 is not arranged to converge to the evaporation portion EP, but extends in only one direction. Therefore, the curved portion 35 does not have a bent portion when viewed from above in the thickness direction Z. Specifically, the curved portion 35 extends only in the longitudinal direction of the housing 10 (length direction Y in Figures 5 and 6) when viewed from above in the thickness direction Z.

[0067] In the example shown in Figs. 5 and 6, two or more rows of curved portions 35 are arranged parallel to each other, but a single row of curved portions 35 may be arranged.

[0068] [Third embodiment] In the heat spreading device according to the third embodiment of the present invention, the curved portion of the wick is disposed along the outer periphery of the internal space of the housing.

[0069] In the third embodiment of the present invention, the curved portion of the wick is not disposed throughout the entire internal space of the housing. Therefore, a wide steam flow path is secured. Therefore, the heat conduction in the center of the internal space of the housing is excellent, and the heat uniformity performance is improved.

[0070] Fig. 7 is a plan view showing an example of the internal structure of a heat spreading device according to a third embodiment of the present invention, Fig. 8 is an example of a cross-sectional view taken along line AA of the heat spreading device shown in Fig. 7.

[0071] In the vapor chamber (heat diffusion device) 3 shown in Figures 7 and 8, the curved portions 35 of the wick 30 are arranged along the outer periphery of the internal space of the housing 10. In the example shown in Figures 7 and 8, two or more rows of curved portions 35 are not arranged in the center of the internal space of the housing 10, but are arranged together along the outer periphery of the internal space of the housing 10.

[0072] 7 and 8, two or more rows of curved portions 35 are arranged parallel to each other, but one row of curved portions 35 may be arranged. In either case, the curved portions 35 are not arranged in the center of the internal space of the housing 10, but are arranged only on the outer periphery of the internal space of the housing 10.

[0073] [Other embodiments] The heat spreading device of the present invention is not limited to the above-described embodiment, and various applications and modifications can be made within the scope of the present invention with respect to the configuration, manufacturing conditions, etc. of the heat spreading device.

[0074] In the heat diffusion device of the present invention, the housing may have one evaporation section or multiple evaporation sections. That is, one heat source may be disposed on the outer wall surface of the housing, or multiple heat sources may be disposed on the outer wall surface of the housing. The number of evaporation sections and heat sources is not particularly limited.

[0075] In the heat spreading device of the present invention, when the housing is composed of a first sheet and a second sheet, the first sheet and the second sheet may overlap so that their ends coincide with each other, or they may overlap so that their ends are misaligned.

[0076] In the heat diffusion device of the present invention, when the housing is composed of a first sheet and a second sheet, the material constituting the first sheet may be different from the material constituting the second sheet. For example, by using a high-strength material for the first sheet, the stress applied to the housing can be dispersed. In addition, by using different materials for both sheets, one sheet can obtain one function and the other sheet can obtain another function. The above functions are not particularly limited, but examples thereof include a heat conduction function and an electromagnetic wave shielding function.

[0077] The heat diffusion device of the present invention can be mounted on an electronic device for the purpose of heat dissipation. Therefore, an electronic device equipped with the heat diffusion device of the present invention is also one of the present inventions. Examples of the electronic device of the present invention include a smartphone, a tablet terminal, a notebook computer, a game device, a wearable device, and the like. As described above, the heat diffusion device of the present invention operates autonomously without requiring an external power source, and can diffuse heat two-dimensionally at high speed by utilizing the latent heat of evaporation and the latent heat of condensation of the working medium. Therefore, the electronic device equipped with the heat diffusion device of the present invention can effectively realize heat dissipation in a limited space inside the electronic device. [Industrial Applicability]

[0078] The heat spreading device of the present invention can be used for a wide range of applications in the field of mobile information terminals, etc. For example, it can be used to lower the temperature of a heat source such as a CPU and extend the operating time of electronic devices, and can be used in smartphones, tablet terminals, notebook computers, etc. [Explanation of symbols]

[0079] 1, 1A, 2, 3 Vapor chamber (thermal diffusion device) 10. Chassis 11 Sheet 1 11a 1st inner wall surface 12 2nd Sheet 12a Second inner wall 20 Working medium 30 Wick 35 music section 40 Liquid flow path 50 Steam flow path 60 pillars EP Evaporation Section HS heat source X Width direction Y Length direction Z thickness direction

Claims

1. a housing having a first inner wall surface and a second inner wall surface opposed to each other in a thickness direction; A working medium sealed in an internal space of the housing; A sheet-shaped wick disposed in the internal space of the housing; a support pillar disposed in the internal space of the housing and in contact with the second inner wall surface, The wick has a curved portion protruding from the first inner wall surface toward the second inner wall surface, A liquid flow path for the working medium is formed in a space surrounded by the curved portion of the wick and the first inner wall surface, The curved portion of the wick is disposed in an area not sandwiched between the support and the first inner wall surface, The wick is a heat spreading device having an area sandwiched between the support and the first inner wall surface.

2. The heat spreading device of claim 1 , wherein the bent portion of the wick extends longitudinally of the housing.

3. The heat spreading device of claim 2 , wherein the bends in the wick extend in only one direction.

4. The heat spreading device according to claim 2 or 3, wherein the curved portions of the wick are arranged in two or more rows parallel to each other.

5. The heat spreading device of claim 2 or 3, wherein the curved portion of the wick is disposed along an outer periphery of the interior space of the housing.

6. A heat diffusion device described in any one of claims 1 to 3, wherein the wick is arranged so as not to contact the second inner wall surface.

7. An electronic device comprising the heat spreading device according to any one of claims 1 to 3.

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