Vapor chambers, capillary sheets for vapor chambers, and electronic devices

Abstract

The vapor chamber (1) of the present invention comprises a first sheet (10), a second sheet (20), and a capillary structure sheet (30). The capillary structure sheet (30) has: a first body surface (31a); a second body surface (31b); a vapor flow path (50) extending from the first body surface (31a) to the second body surface (31b) for passing through vapor (2a) of the actuating fluid; and a liquid flow path (60) disposed on the second body surface (31b), communicating with the vapor flow path (50) and for passing through liquid actuating fluid (2b). The liquid flow path section (60) has a plurality of main liquid flow path channels (61a to 61f) through which a liquid actuating fluid (2b) passes. Among the plurality of main liquid flow path channels (61a to 61f), the width (w3a, w3f) of the main liquid flow path channel (61a, 61f) closest to the vapor flow path section (50) is wider than the width (w3b to w3e) of the other main liquid flow path channels (61b to 61e).

Description

Technical Field

[0001] This invention relates to a vapor chamber, a capillary sheet for the vapor chamber, and an electronic device. Prior Technology

[0002] Central processing units (CPUs), light-emitting diodes (LEDs), and power semiconductors used in mobile terminals such as mobile phones and tablets are devices that generate heat. These heat-generating devices are cooled by heat dissipation components such as heat pipes. In recent years, the need for thinner heat dissipation components has also increased in the pursuit of thinner mobile terminals. Therefore, the development of vapor chambers, which can achieve thinner designs compared to heat pipes, is underway. An actuating fluid is sealed inside the vapor chamber. The actuating fluid absorbs and diffuses the heat from the device, thereby cooling the device. For example, Patent Document 1 discloses a sheet-type heat pipe made by stacking two or more metal foil sheets.

[0003] More specifically, the actuating fluid in the vapor chamber receives heat from the device and evaporates into vapor (actuating vapor) near the device (evaporation section). This actuating vapor diffuses away from the evaporation section within the vapor flow path and is cooled, condensing into a liquid state. A liquid flow path, forming a capillary structure, is provided within the vapor chamber. The condensed, liquid actuating fluid (actuating liquid) enters the liquid flow path from the vapor flow path and flows towards the evaporation section. Furthermore, the actuating liquid receives heat again in the evaporation section and evaporates. In this way, the actuating fluid repeatedly undergoes phase change, i.e., evaporation and condensation, while simultaneously flowing back within the vapor chamber, thereby improving heat transfer efficiency within the device. [Previous Technical Documents] [Patent Literature]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2016-017702

[0005] The purpose of this embodiment is to provide a vapor chamber with excellent cooling capacity, a capillary sheet for the vapor chamber, and an electronic device equipped with the above. Summary of the Invention

[0006] The vapor chamber of this embodiment is sealed with an actuating fluid and includes: a first sheet; a second sheet; and a capillary structure sheet disposed between the first sheet and the second sheet; the capillary structure sheet has: a first body surface; a second body surface located on the opposite side of the first body surface; a vapor flow path extending from the first body surface to the second body surface for through which vapor of the actuating fluid passes; and a liquid flow path disposed on the second body surface, communicating with the vapor flow path and for through which liquid of the actuating fluid passes; the liquid flow path has a plurality of main liquid flow channels arranged in parallel to each other for through which liquid of the actuating fluid passes, and among the plurality of main liquid flow channels, the width of the main liquid flow channel closest to the vapor flow path is wider than the width of the other main liquid flow channels.

[0007] In the vapor chamber of this embodiment, the width of the main liquid flow channel closest to the vapor flow channel can be more than 1.1 times and less than 1.6 times the width of the other main liquid flow channels.

[0008] In the vapor chamber of this embodiment, the depth of the main liquid flow channel closest to the vapor flow path can also be deeper than the depth of the other main liquid flow channels.

[0009] In the vapor chamber of this embodiment, the center-to-center distances in the width direction of the plurality of liquid flow path main channels can also be equal to each other.

[0010] In the vapor chamber of this embodiment, rows of protrusions may be provided between adjacent main channels of the liquid flow path, each row of protrusions having a plurality of protrusions, and the spacing between the protrusions in the length direction of the main channel of the liquid flow path is equal between the protrusions.

[0011] In the vapor chamber of this embodiment, the width of the plurality of liquid flow path main channels can also gradually narrow from the liquid flow path main channel closest to the vapor flow path section toward the liquid flow path main channel located inside the width direction of the liquid flow path section.

[0012] The capillary sheet of this embodiment is a capillary sheet for a vapor chamber and has: a first body surface; a second body surface located on the opposite side of the first body surface; a vapor flow path extending from the first body surface to the second body surface for passing through vapor of the actuating fluid; and a liquid flow path disposed on the second body surface, communicating with the vapor flow path and for passing through liquid of the actuating fluid; the liquid flow path has a plurality of main liquid flow channels arranged in parallel to each other for passing through liquid of the actuating fluid, and among the plurality of main liquid flow channels, the width of the main liquid flow channel closest to the vapor flow path is wider than the width of the other main liquid flow channels.

[0013] In the capillary structure sheet of this embodiment, the width of the main liquid flow channel closest to the vapor flow channel can be more than 1.1 times and less than 1.6 times the width of the other main liquid flow channels.

[0014] In the capillary structure sheet of this embodiment, the depth of the main liquid flow channel closest to the vapor flow channel can also be deeper than the depth of the other main liquid flow channels.

[0015] In the capillary structure sheet of this embodiment, the center-to-center distances in the width direction of the plurality of liquid flow path main channels can also be equal to each other.

[0016] In the capillary structure sheet of this embodiment, rows of protrusions may be provided between adjacent main channels of the liquid flow path, each row of protrusions having a plurality of protrusions, and the spacing between the protrusions in the length direction of the main channel of the liquid flow path is equal between the protrusions.

[0017] In the capillary structure sheet of this embodiment, the width of the plurality of liquid flow path main channels can also gradually narrow from the liquid flow path main channel closest to the vapor flow path to the liquid flow path main channel located inside the width direction of the liquid flow path.

[0018] The electronic device of this embodiment includes: a housing; a device housed within the housing; and a vapor chamber of this embodiment that is in thermal contact with the device.

[0019] According to an embodiment of the present invention, a vapor chamber with excellent cooling capacity can be provided.

[0020] The vapor chamber of this embodiment is sealed with an actuating fluid and includes: a first sheet; a second sheet; and a capillary structure sheet disposed between the first sheet and the second sheet; the capillary structure sheet has: a first body surface; a second body surface located on the opposite side of the first body surface; a vapor flow path extending from the first body surface to the second body surface for the passage of vapor of the actuating fluid; and a liquid flow path disposed on the second body surface, communicating with the vapor flow path and for the passage of liquid actuating fluid; the liquid flow path has a plurality of main liquid flow channels arranged in parallel to each other for the passage of liquid actuating fluid, and a row of protrusions is provided between adjacent main liquid flow channels, each row of protrusions having a plurality of protrusions, and the width of the protrusions in the row of protrusions closest to the vapor flow path is narrower than the width of the protrusions in the other rows of protrusions.

[0021] In the steam chamber of this embodiment, the width of the protrusion closest to the steam flow path can be more than 0.3 times and less than 0.95 times the width of the protrusions of the other protrusion rows.

[0022] In the steam chamber of this embodiment, the spacing between the protrusions of the protrusion row closest to the steam flow path and the protrusions of the protrusion row adjacent to the protrusion row can also be narrower than the spacing between the protrusions of the other protrusion rows.

[0023] In the vapor chamber of this embodiment, the widths of the aforementioned plurality of liquid flow path main channels can also be equal to each other.

[0024] In the vapor chamber of this embodiment, among the plurality of liquid flow path main channels, the width of the liquid flow path main channel closest to the vapor flow path can also be wider than the width of the other liquid flow path main channels.

[0025] In the vapor chamber of this embodiment, the width of the plurality of protrusions can gradually increase from the protrusion closest to the vapor flow path to the protrusion located inside the width direction of the liquid flow path.

[0026] The capillary sheet of this embodiment is a capillary sheet for a vapor chamber and has: a first body surface; a second body surface located on the opposite side of the first body surface; a vapor flow path extending from the first body surface to the second body surface for passing through vapor of the actuating fluid; and a liquid flow path disposed on the second body surface, communicating with the vapor flow path and for passing through liquid of the actuating fluid; the liquid flow path has a plurality of main liquid flow channels arranged in parallel to each other for passing through liquid of the actuating fluid, and a row of protrusions is provided between adjacent main liquid flow channels, each row of protrusions having a plurality of protrusions, and the width of the protrusions in the row of protrusions closest to the vapor flow path is narrower than the width of the protrusions in the other rows of protrusions.

[0027] In the capillary sheet of this embodiment, the width of the protrusion of the protrusion row closest to the above-mentioned vapor flow path can be more than 0.3 times and less than 0.95 times the width of the protrusion of the other protrusion rows.

[0028] In the capillary sheet of this embodiment, the spacing between the protrusions of the protrusion row closest to the vapor flow path and the protrusions of the protrusion row adjacent to the protrusion row can also be narrower than the spacing between the protrusions of the other protrusion rows.

[0029] In the capillary structure sheet of this embodiment, the widths of the plurality of liquid flow path main channels can also be equal to each other.

[0030] In the capillary structure sheet of this embodiment, among the plurality of liquid flow path main channels, the width of the liquid flow path main channel closest to the vapor flow path can also be wider than the width of the other liquid flow path main channels.

[0031] In the capillary sheet of this embodiment, the width of the plurality of protrusions can gradually increase from the protrusion closest to the vapor flow path to the protrusion located inside the width direction of the liquid flow path.

[0032] The electronic device of this embodiment includes: a housing; a device housed within the housing; and a vapor chamber of this embodiment that is in thermal contact with the device.

[0033] According to an embodiment of the present invention, the cooling capacity of the steam chamber can be improved. Simple Explanation of the Diagram

[0034] Figure 1 is a schematic perspective view illustrating the electronic device of the first embodiment. Figure 2 is a top view of the steam chamber in the first embodiment. Figure 3 is a cross-sectional view along line III-III of the vapor chamber in Figure 2. Figure 4 is a top view of the lower sheet in Figure 3. Figure 5 is a bottom view of the upper sheet in Figure 3. Figure 6 is a top view of the capillary sheet shown in Figure 3. Figure 7 is a bottom view of the capillary sheet shown in Figure 3. Figure 8 is a partially enlarged sectional view of Figure 3. Figure 9 is a partially enlarged top view of the liquid flow path shown in Figure 6. Figures 10(a)-(c) illustrate the method for manufacturing the steam chamber according to the first embodiment. Figure 11 is a partially enlarged cross-sectional view of the liquid flow path section of the first variation of the first embodiment. Figure 12 is a partially enlarged top view of the liquid flow path section of the first variation of the first embodiment. Figure 13 is a partially enlarged cross-sectional view of the liquid flow path section in the second variation of the first embodiment. Figure 14 is a partially enlarged top view of the liquid flow path section in the second variation of the first embodiment. Figure 15 is a partially enlarged cross-sectional view of the liquid flow path section in the third variation of the first embodiment. Figure 16 is a partially enlarged top view of the liquid flow path section in the third variation of the first embodiment. Figure 17 is a partially enlarged top view of the liquid flow path section in the fourth variation of the first embodiment. Figure 18 is a partially enlarged cross-sectional view of the steam chamber in the second embodiment. Figure 19 is a partially enlarged top view of the liquid flow path of the capillary sheet according to the second embodiment. Figure 20 is a partially enlarged cross-sectional view of the liquid flow path section in the first variation of the second embodiment. Figure 21 is a partially enlarged top view of the liquid flow path section of the first variation of the second embodiment. Figure 22 is a partially enlarged cross-sectional view of the liquid flow path section in the second variation of the second embodiment. Figure 23 is a partially enlarged top view of the liquid flow path section of the second variation of the second embodiment. Figure 24 is a partially enlarged cross-sectional view of the liquid flow path section in the third variation of the second embodiment. Figure 25 is a partially enlarged top view of the liquid flow path section in the third variation of the second embodiment. Figure 26 is a partially enlarged top view of the liquid flow path section in the fourth variation of the second embodiment. Implementation

[0035] (First Embodiment) The first embodiment will now be described with reference to Figures 1 to 17. Furthermore, in the accompanying drawings, for ease of illustration and understanding, the scale and aspect ratios have been appropriately altered and exaggerated compared to the actual object.

[0036] Furthermore, the specific shapes, geometric conditions, and physical properties used in this specification, such as terms like "parallel," "orthogonal," and "identical," or values ​​of length, angle, and physical properties, are not limited to their strict meanings. These terms or values ​​are interpreted within a range of the degree to which the same function can be expected. Moreover, in the drawings, for clarity, the shapes of multiple parts that can be expected to have the same function are systematically depicted. Furthermore, not limited to a strict meaning, the shapes of these parts may differ within the range to which the function can be expected. Also, in the drawings, for convenience, the boundary lines representing the joint surfaces of components are shown only as straight lines. The boundary lines are not limited to strictly straight lines. The shape of the boundary lines is arbitrary within the range to which the desired joint performance can be expected.

[0037] Using Figures 1 to 10, the vapor chamber, the capillary sheet for the vapor chamber, and the electronic device in this embodiment will be described. The vapor chamber 1 in this embodiment is a device mounted on the electronic device E to cool the heat-generating device D housed within the electronic device E. Examples of device D include heat-generating electronic devices (cooled devices) used in mobile terminals such as mobile terminals or tablet terminals. Examples of heat-generating electronic devices include central processing units (CPUs), light-emitting diodes (LEDs), and power semiconductors.

[0038] Here, we will first describe an electronic device E equipped with the vapor chamber 1 of this embodiment, taking a tablet terminal as an example. As shown in FIG1, the electronic device E (e.g., a tablet terminal) includes a housing H, a device D housed within the housing H, and a vapor chamber 1. In the electronic device E shown in FIG1, a touch panel display TD is provided on the front surface of the housing H. The vapor chamber 1 is housed within the housing H and is arranged in thermal contact with the device D. In this way, the vapor chamber 1 can receive the heat generated in the device D when the electronic device E is used. The heat received by the vapor chamber 1 is released to the outside of the vapor chamber 1 via the actuating fluids 2a and 2b described below. In this way, the device D is effectively cooled. When the electronic device E is a tablet terminal, the device D is equivalent to a central processing unit, etc.

[0039] Next, the vapor chamber 1 of this embodiment will be described. As shown in Figures 2 and 3, the vapor chamber 1 has a sealed space 3 containing the actuating fluids 2a and 2b. The vapor chamber 1 is configured such that the device D of the electronic device E is effectively cooled by repeated phase changes of the actuating fluids 2a and 2b within the sealed space 3. Examples of actuating fluids 2a and 2b include pure water, ethanol, methanol, acetone, and mixtures thereof. Furthermore, the actuating fluids 2a and 2b may also have freeze-expansion properties. That is, the actuating fluids 2a and 2b may be fluids that expand upon freezing. Examples of actuating fluids 2a and 2b with freeze-expansion properties include pure water or an aqueous solution obtained by adding additives such as alcohol to pure water.

[0040] As shown in Figures 2 and 3, the steam chamber 1 includes a lower sheet 10 (first sheet), an upper sheet 20 (second sheet), and a capillary sheet for the steam chamber (hereinafter referred to as capillary sheet 30). The capillary sheet 30 is disposed between the lower sheet 10 and the upper sheet 20. In the steam chamber 1 of this embodiment, the lower sheet 10, the capillary sheet 30, and the upper sheet 20 are laminated in this order.

[0041] The steam cavity 1 is generally formed as a thin, flat plate. The planar shape of the steam cavity 1 is arbitrary, and can also be rectangular as shown in Figure 2. For example, the planar shape of the steam cavity 1 can be a rectangle with one side between 50 mm and 200 mm and another side between 60 mm and 150 mm, or a square with one side between 70 mm and 300 mm. The planar dimensions of the steam cavity 1 are arbitrary. In this embodiment, as an example, we will describe an example where the planar shape of the steam cavity 1 is a rectangle with the X direction set as the length direction. In this case, as shown in Figures 4 to 7, the lower sheet 10, the upper sheet 20, and the capillary sheet 30 can also have the same planar shape as the steam cavity 1. Furthermore, the planar shape of the steam cavity 1 is not limited to a rectangle; it can be any shape such as circular, elliptical, L-shaped, or T-shaped.

[0042] As shown in Figure 2, the vapor chamber 1 has an evaporation region SR for evaporating the working fluids 2a and 2b, and a condensation region CR for condensing the working fluids 2a and 2b.

[0043] The evaporation region SR is the area overlapping with device D in a top view, and is the area for mounting device D. The evaporation region SR can be disposed at any location in the vapor chamber 1. In this embodiment, the evaporation region SR is formed on one side of the vapor chamber 1 in the X direction (the left side in FIG2). Heat from device D is transferred to the evaporation region SR, where it evaporates in the evaporation region SR by means of the hot and liquid actuating fluid (appropriately referred to as actuating fluid 2b). Heat from device D is not only transferred to the area overlapping with device D in a top view, but may also be transferred to the periphery of that area. Therefore, the evaporation region SR includes the area overlapping with device D in a top view and the area surrounding it. Here, "top view" refers to the state viewed from a direction orthogonal to the surface of the vapor chamber 1 that receives heat from device D (the second upper sheet surface 20b of the upper sheet 20 below) and the surface that releases the received heat (the first lower sheet surface 10a of the lower sheet 10 below). That is, looking down is equivalent to observing the state of the steam chamber 1 from above or from below, as shown in Figure 2.

[0044] The condensation region CR is the area that does not overlap with device D when viewed from above, and it is the main area where the actuating vapor 2a releases heat and condenses. The condensation region CR can also refer to the area around the evaporation region SR. In the condensation region CR, the heat from the actuating vapor 2a is released to the lower sheet 10, and the actuating vapor 2a is cooled and condensed in the condensation region CR.

[0045] Furthermore, when the vapor chamber 1 is located inside the mobile terminal, the vertical relationship may be disrupted depending on the posture of the mobile terminal. However, for convenience in this embodiment, the sheet that receives heat from device D is referred to as the upper sheet 20, and the sheet that releases the received heat is referred to as the lower sheet 10. Therefore, the following description will be based on the state where the lower sheet 10 is positioned on the lower side and the upper sheet 20 is positioned on the upper side.

[0046] As shown in Figure 3, the lower sheet 10 has a first lower sheet surface 10a located opposite to the capillary sheet 30, and a second lower sheet surface 10b located opposite to the first lower sheet surface 10a (i.e., the side of the capillary sheet 30). The lower sheet 10 can also be formed as a whole flat, and the lower sheet 10 can also have a fixed thickness as a whole. A housing member Ha, which constitutes part of the housing of a mobile terminal, etc., is installed on the first lower sheet surface 10a. Alternatively, the entire first lower sheet surface 10a can be covered by the housing member Ha. As shown in Figure 4, alignment holes 12 can also be provided at the four corners of the lower sheet 10.

[0047] As shown in Figure 3, the upper sheet 20 has a first upper sheet surface 20a disposed on the side of the capillary sheet 30, and a second upper sheet surface 20b disposed on the opposite side of the first upper sheet surface 20a. The upper sheet 20 can also be formed as a whole flat, and the upper sheet 20 can also have a fixed thickness as a whole. The aforementioned device D is mounted on the second upper sheet surface 20b. As shown in Figure 5, alignment holes 22 can also be provided at the four corners of the upper sheet 20.

[0048] As shown in Figure 3, the capillary sheet 30 includes a vapor flow path 50 and a liquid flow path 60 disposed adjacent to the vapor flow path 50. Furthermore, the capillary sheet 30 has a first body surface 31a and a second body surface 31b located opposite to the first body surface 31a. The first body surface 31a is disposed on the lower sheet 10 side, and the second body surface 31b is disposed on the upper sheet 20 side.

[0049] The second lower sheet surface 10b of the lower sheet 10 and the first body surface 31a of the capillary sheet 30 can also be permanently bonded to each other by diffusion bonding. Similarly, the first upper sheet surface 20a of the upper sheet 20 and the second body surface 31b of the capillary sheet 30 can also be permanently bonded to each other by diffusion bonding. Furthermore, as long as the lower sheet 10, upper sheet 20 and capillary sheet 30 can be permanently bonded, they can also be bonded by other methods such as hard welding, rather than diffusion bonding. Furthermore, the term "permanently bonded" is not limited to a strict meaning. "Permanently bonded" means that when the vapor chamber 1 is in operation, the bond between the lower sheet 10 and the capillary sheet 30 can be maintained to a degree that can maintain the sealing of the sealed space 3, and the bond can be maintained to a degree that can maintain the bond between the upper sheet 20 and the capillary sheet 30.

[0050] As shown in Figures 3, 6, and 7, the capillary sheet 30 of this embodiment has a frame portion 32 formed into a rectangular frame shape in top view, and an island portion 33 disposed within the frame portion 32. The frame portion 32 and the island portion 33 are the portions of the capillary sheet 30 that are not etched in the etching steps described below and are the material residues. In this embodiment, the frame portion 32 is formed into a rectangular frame shape in top view. A vapor flow path portion 50 is defined inside the frame portion 32. That is, actuating vapor 2a flows inside the frame portion 32 and around the island portion 33.

[0051] In this embodiment, the island portion 33 can also extend elongatedly in the X direction (first direction, left-right direction in FIG. 6) as its length direction when viewed from above. The planar shape of the island portion 33 can also be an elongated rectangular shape. Furthermore, each island portion 33 can also be equally spaced and arranged parallel to each other in the Y direction (second direction, up-down direction in FIG. 6). This configuration allows the actuating vapor 2a to flow around each island portion 33 and be transported toward the condensation region CR. In this way, the flow of the actuating vapor 2a is suppressed. The width w1 of the island portion 33 (refer to FIG. 8) can be, for example, 30 μm or more and 3000 μm or less. Here, the width w1 of the island portion 33 refers to the dimension of the island portion 33 in the Y direction, specifically the dimension at the thickest point of the island portion 33 (for example, the location of the protrusion 55 described below).

[0052] The frame portion 32 and each island portion 33 are diffusely bonded to the lower sheet 10 and diffusely bonded to the upper sheet 20. This improves the mechanical strength of the steam chamber 1. The first wall surface 53a and the second wall surface 54a of the steam passage 51 described below constitute the sidewalls of the island portion 33. The first body surface 31a and the second body surface 31b of the capillary sheet 30 can also be formed flat throughout the frame portion 32 and each island portion 33.

[0053] The vapor flow path 50 is a flow path through which the vapor of the actuating fluid (appropriately referred to as actuating vapor 2a) passes. The vapor flow path 50 extends from the first body surface 31a to the second body surface 31b and penetrates the capillary sheet 30.

[0054] As shown in Figures 6 and 7, the steam flow path 50 in this embodiment has a plurality of steam passages 51. Each steam passage 51 is formed inside the frame portion 32 and outside the island portion 33. That is, the steam passages 51 are formed between the frame portion 32 and the island portion 33, and between adjacent island portions 33. The planar shape of each steam passage 51 is an elongated rectangular shape. The steam flow path 50 is divided into a plurality of steam passages 51 by the plurality of island portions 33.

[0055] As shown in Figure 3, the vapor passage 51 is formed extending from the first body surface 31a of the capillary sheet 30 to the second body surface 31b.

[0056] The vapor passage 51 can also be formed by etching the first body surface 31a and the second body surface 31b of the capillary sheet 30 in the following etching steps. In this case, as shown in FIG8, the vapor passage 51 has a first wall surface 53a and a second wall surface 54a that are formed in a curved shape. The first wall surface 53a is located on the side of the first body surface 31a and is curved in a shape that bulges toward the second body surface 31b. The second wall surface 54a is located on the side of the second body surface 31b and is curved in a shape that bulges toward the first body surface 31a. The first wall surface 53a and the second wall surface 54a meet at a protrusion 55 that protrudes toward the inner side of the vapor passage 51. The protrusion 55 can also be formed as an acute angle when viewed in cross-section. At the location of the protrusion 55, the planar area of ​​the vapor passage 51 is minimized. The width w2 of the steam passage 51 (see Figure 8) can be, for example, 100 μm or more, or 400 μm or more. The width w2 of the steam passage 51 can be less than 5000 μm, or less than 1600 μm. Here, the width w2 of the steam passage 51 refers to the width of the narrowest part of the steam passage 51, which in this case refers to the distance measured in the width direction (Y direction) at the location of the protrusion 55. Furthermore, the width w2 of the steam passage 51 corresponds to the gap between adjacent island portions 33 in the width direction (Y direction).

[0057] The position of the protrusion 55 in the thickness direction (Z direction) of the capillary sheet 30 is offset towards the second body surface 31b relative to the midpoint between the first body surface 31a and the second body surface 31b. When the distance between the protrusion 55 and the second body surface 31b is set as t5, the distance t5 can be more than 5%, more than 10%, or more than 20% of the thickness t4 of the capillary sheet 30, or less than 50%, less than 40%, or less than 30% of the thickness t4 of the capillary sheet 30. Furthermore, it is not limited to this; the position of the protrusion 55 in the thickness direction (Z direction) of the capillary sheet 30 can also be the midpoint between the first body surface 31a and the second body surface 31b, or it can be a position offset towards the first body surface 31a relative to the midpoint. As long as the vapor passage 51 extends through the capillary sheet 30 in the thickness direction (Z direction), the position of the protrusion 55 is arbitrary.

[0058] Furthermore, in this embodiment, the cross-sectional shape of the steam passage 51 is defined by the protrusion 55 that protrudes inward, but it is not limited to this. For example, the cross-sectional shape of the steam passage 51 may also be trapezoidal or rectangular, or it may also be barrel-shaped.

[0059] The vapor passage 51, which includes the vapor flow path 50 configured in this way, constitutes a part of the aforementioned sealed space 3. As shown in FIG3, the vapor flow path 50 of this embodiment is mainly defined by the lower sheet 10, the upper sheet 20, and the frame portion 32 and island portion 33 of the aforementioned capillary structure sheet 30. Each vapor passage 51 has a relatively large flow path cross-sectional area to allow the actuating vapor 2a to pass through.

[0060] Here, Figure 3 shows the steam passages 51 enlarged for clarity, and the number or arrangement of these steam passages 51 are different from those in Figures 2, 6 and 7.

[0061] Furthermore, as shown in Figures 6 and 7, a support portion 39 is provided within the vapor flow path 50 to support the island platform 33 on the frame portion 32. The support portion 39 supports adjacent island platform portions 33. The support portion 39 is provided on both sides of the island platform portion 33 in the longitudinal direction (X direction). Preferably, the support portion 39 is formed so as not to obstruct the flow of actuating vapor 2a diffused in the vapor flow path 50. In this case, the support portion 39 is disposed on the first body surface 31a side of the capillary structure sheet 30, and a space communicating with the vapor flow path 50 is formed on the second body surface 31b side. In this way, the thickness of the support portion 39 can be thinner than the thickness of the capillary structure sheet 30, which can prevent the vapor passage 51 from being interrupted in the X and Y directions. However, it is not limited to this, the support portion 39 can also be disposed on the second body surface 31b side. Alternatively, a space communicating with the vapor flow path section 50 can be formed on both the first body surface 31a side and the second body surface 31b side of the support section 39.

[0062] As shown in Figures 6 and 7, alignment holes 35 can also be provided at the four corners of the capillary sheet 30.

[0063] Furthermore, as shown in Figure 2, the vapor chamber 1 may also have an injection section 4 at one end edge in the X direction for injecting the actuating fluid 2b into the sealed space 3. In the configuration shown in Figure 2, the injection section 4 is disposed on the evaporation region SR side. The injection section 4 has an injection flow path 37 formed on the capillary sheet 30. This injection flow path 37 is formed on the second body surface 31b side of the capillary sheet 30 and is concave from the second body surface 31b side. After the vapor chamber 1 is completed, the injection flow path 37 becomes sealed. Furthermore, the injection flow path 37 communicates with the vapor flow path 50, and the actuating fluid 2b is injected into the sealed space 3 through the injection flow path 37. Moreover, depending on the configuration of the liquid flow path 60, the injection flow path 37 may also communicate with the liquid flow path 60.

[0064] Furthermore, in this embodiment, an example is shown where the injection portion 4 is disposed on one side edge of one pair of end edges in the X direction of the vapor chamber 1, but it is not limited to this and can be disposed at any position. Furthermore, the injection portion 4 can also be pre-formed such that it protrudes from one side edge in the X direction of the vapor chamber 1.

[0065] As shown in Figures 3, 6, and 8, a liquid flow path 60 is disposed on the second body surface 31b of the capillary structure sheet 30. The liquid flow path 60 primarily allows the actuating fluid 2b to pass through. This liquid flow path 60 constitutes a part of the aforementioned sealed space 3 and communicates with the vapor flow path 50. The liquid flow path 60 is configured as a capillary structure (capillary structure) for transporting the actuating fluid 2b to the evaporation zone SR. In this embodiment, the liquid flow path 60 is disposed on the second body surface 31b of each island portion 33 of the capillary structure sheet 30. Alternatively, the liquid flow path 60 may be formed covering the entire second body surface 31b of each island portion 33.

[0066] As shown in Figure 9, the liquid flow path section 60 has a plurality of main liquid flow path channels 61a-61f through which the actuating fluid 2b passes and arranged in parallel with each other, and a plurality of liquid flow path connecting channels 65 communicating with the main liquid flow path channels 61a-61f. Furthermore, in the example shown in Figure 9, each island section 33 includes six main liquid flow path channels 61a-61f, but it is not limited to this. The number of main liquid flow path channels included in each island section 33 is arbitrary; for example, it can be more than three and less than twenty.

[0067] As shown in Figure 9, each of the main flow channels 61a-61f extends along the length direction (X direction) of the island portion 33. The plurality of main flow channels 61a-61f are arranged parallel to each other. Furthermore, when the island portion 33 is curved in plan view, each main flow channel 61a-61f may also extend in a curved shape along the curvature direction of the island portion 33. That is, each main flow channel 61a-61f may not necessarily be formed in a straight line, and may not necessarily extend parallel to the X direction.

[0068] The main liquid flow channels 61a-61f have a smaller cross-sectional area than the vapor passage 51 of the vapor flow channel 50, primarily for the flow of the actuating liquid 2b via capillary action. The main liquid flow channels 61a-61f are configured to transport the actuating liquid 2b, which is condensed from the self-actuating vapor 2a, to the evaporation zone SR. The main liquid flow channels 61a-61f are spaced apart from each other in the width direction (Y direction).

[0069] The main liquid flow channels 61a-61f are formed by etching from the second body surface 31b of the capillary sheet 30 in the following etching step. As shown in FIG8, the main liquid flow channels 61a-61f have curved walls 62. These walls 62 define the main liquid flow channels 61a-61f and are curved in a shape that bulges towards the first body surface 31a. Furthermore, in the cross-section shown in FIG8, the radius of curvature of each wall 62 is preferably smaller than the radius of curvature of the second wall surface 54a of the vapor passage 51.

[0070] As shown in Figure 9, the widths of the main liquid flow channels 61a to 61f are not all equal among them. The two main liquid flow channels 61a and 61f (hereinafter also referred to as main liquid flow channels 61a and 61f) closest to the vapor flow section 50 (vapor passage 51) are wider than the other main liquid flow channels 61b to 61e (hereinafter also referred to as main liquid flow channels 61b to 61e). That is, when the widths of the main liquid flow channels 61a to 61f are set to w3a to w3f respectively, the widths w3a and w3f of the main liquid flow channels 61a and 61f are wider than the widths w3b to w3e of the main liquid flow channels 61b to 61e (w3a and w3f > w3b to w3e).

[0071] In Figure 9, the widths w3a and w3f of the main flow channels 61a and 61f located on the outer side of the width direction of each liquid flow channel 60 are equal, and the widths w3b and w3e of the main flow channels 61b to 61e located on the inner side of the width direction of each liquid flow channel 60 are equal. That is, the relationship w3a=w3f>w3b=w3c=w3d=w3e holds. In this case, the cross-sectional shape (depth, width, etc.) of the plurality of main flow channels 61a to 61f can also be symmetrical with respect to the centerline of the width direction (Y direction) of the island 33. However, it is not limited to this, and the widths w3a and w3f of the main flow channels 61a and 61f can also be different. Furthermore, the widths w3b and w3e of the main flow channels 61b to 61e can also be different. However, it is preferable that the narrower of the widths w3a and w3f of the main flow channels 61a and 61f is wider than the widest of the widths w3b and w3e of the main flow channels 61b to 61e.

[0072] The widths w3a and w3f of the main liquid flow channels 61a and 61f are preferably 1.1 to 1.6 times the widths w3b and w3e of the main liquid flow channels 61b and 61e. By making this ratio 1.1 times or more, the capillary force in the central main liquid flow channels 61b and 61e can be increased, making it easier to transport the actuating liquid 2b towards the evaporation zone SR. Furthermore, by making the main liquid flow channels 61a and 61f located on the outer side of each liquid flow section 60 in the width direction wider, a large amount of actuating liquid 2b can be transported towards the evaporation zone SR. Also, when the flow of actuating liquid 2b towards the main liquid flow channels 61b and 61e located on the inner side of each liquid flow section 60 in the width direction stagnates, the condensation of the actuating liquid 2b from the vapor flow section 50 is less likely to be obstructed. On the other hand, by making the aforementioned ratio 1.6 times or less, the reduction in the delivery volume of the actuating fluid 2b in the main flow channels 61b-61e located inside the width direction of each liquid flow section 60 can be suppressed. Furthermore, the reduction in capillary force in the main flow channels 61a and 61f located outside the width direction of each liquid flow section 60 can be suppressed. Moreover, the actuating fluid 2b can easily flow from the main flow channels 61a and 61f located outside the width direction of each liquid flow section 60 to the main flow channels 61b-61e located inside the width direction.

[0073] Furthermore, the widths w3a to w3f of the main flow channels 61a to 61f refer to the lengths in the direction perpendicular to the length direction of the island portion 33, and in this case, the dimensions in the Y direction. Also, the widths w3a to w3f of the main flow channels 61a to 61f refer to the dimensions within the second body surface 31b. Furthermore, the widths w3a and w3f of the main flow channels 61a and 61f located on the outer side of each liquid flow section 60 in the width direction can, for example, be 5.5 μm or more and 320 μm or less. The widths w3b to w3e of the main flow channels 61b to 61e located on the inner side of each liquid flow section 60 in the width direction can, for example, be 2.2 μm or more and 290 μm or less.

[0074] Furthermore, as shown in Figure 8, the depths h1a and h1b of the main flow channels 61a to 61f may not all be equal among them. Specifically, the depth h1a of the main flow channels 61a and 61f located on the outer side of the width direction of each liquid flow section 60 may be deeper than the depth h1b of the main flow channels 61b to 61e located on the inner side of the width direction (h1a > h1b). In this case, the depths h1a of the main flow channels 61a and 61f are equal to each other, and the depths h1b of the main flow channels 61b to 61e are equal to each other. However, this is not a limitation; the depths h1a of the main flow channels 61a and 61f may also be different from each other. Furthermore, the depths h1b of the main flow channels 61b to 61e may also be different from each other. The depth h1a of the main flow channels 61a and 61f can be set to, for example, 3.5 μm or more and 240 μm or less. The depth h1b of the main flow channels 61b to 61e can be set to, for example, 3 μm or more and 200 μm or less.

[0075] Furthermore, the depths h1a and h1b of the main flow channels 61a to 61f are distances measured from the second body surface 31b in a direction perpendicular to the second body surface 31b, and in this case, they are dimensions in the Z direction. Also, depths h1a and h1b refer to the depth of the deepest part of the main flow channels 61a to 61f.

[0076] As shown in Figure 9, each liquid flow path connecting groove 65 extends in a direction different from the X direction. In this embodiment, each liquid flow path connecting groove 65 is formed to extend along the Y direction and is formed perpendicular to the main liquid flow path grooves 61a-61f. Several liquid flow path connecting grooves 65 are arranged such that adjacent main liquid flow path grooves 61a-61f are connected to each other. Other liquid flow path connecting grooves 65 are arranged such that the vapor flow path section 50 (vapor passage 51) is connected to the main liquid flow path grooves 61a and 61f closest to the vapor flow path section 50. That is, the liquid flow path connecting groove 65 extends from the end side of the island section 33 in the Y direction to the main liquid flow path grooves 61a and 61f adjacent to that end. In this way, the vapor passage 51 of the vapor flow path section 50 is connected to the main liquid flow path grooves 61a-61f.

[0077] The liquid flow path connecting groove 65 has a smaller flow path cross-sectional area than the vapor passage 51 of the vapor flow path section 50, so as to mainly allow the actuating liquid 2b to flow by capillary action. Each liquid flow path connecting groove 65 can also be arranged at equal intervals along the length direction (X direction) of the island section 33.

[0078] The liquid flow path connecting groove 65, like the main liquid flow path grooves 61a-61f, is formed by etching and has a curved wall surface (not shown), similar to the main liquid flow path grooves 61a-61f. As shown in Figure 9, the width w4 (dimension in the X direction) of the liquid flow path connecting groove 65 can be set to 5 μm or more and 300 μm or less. The depth of the liquid flow path connecting groove 65 can be set to 3 μm or more and 240 μm or less.

[0079] The main flow channels 61a-61f include a flow channel intersection 66 communicating with the flow channel connecting channel 65. At the flow channel intersection 66, the main flow channels 61a-61f and the flow channel connecting channel 65 are connected in a T-shape. In this case, at the flow channel intersection 66, one main flow channel 61a-61f communicates with the flow channel connecting channel 65 on one side (e.g., the upper side in FIG. 9). This prevents the flow channel connecting channel 65 on the other side (e.g., the lower side in FIG. 9) from communicating with the main flow channel 61a-61f at the flow channel intersection 66. Therefore, at the flow channel intersection 66, the wall 62 of the main flow channels 61a-61f is not cut open on both sides in the Y direction, allowing one side of the wall 62 to remain intact. Therefore, at the liquid flow path intersection 66, the actuating fluid 2b in the main liquid flow path channel 61a~61f can also be given a capillary effect, thereby suppressing the reduction of the propulsion force of the actuating fluid 2b toward the evaporation region SR at the liquid flow path intersection 66.

[0080] As shown in Figure 9, rows of protrusions 63 are provided between adjacent main liquid flow channels 61a-61f. Each row of protrusions 63 includes a plurality of protrusions 64 (liquid flow channel protrusions) arranged along the X direction. The protrusions 64 are disposed within the liquid flow channel portion 60, protruding from the main liquid flow channels 61a-61f and the liquid flow channel connecting groove 65 and abutting against the upper sheet 20. Each protrusion 64 is formed in a rectangular shape such that the X direction is the length direction when viewed from above. Main liquid flow channels 61a-61f are arranged between adjacent protrusions 64 in the Y direction. Liquid flow channel connecting grooves 65 are arranged between adjacent protrusions 64 in the X direction. The liquid flow channel connecting grooves 65 are formed to extend along the Y direction, so that adjacent main liquid flow channels 61a-61f in the Y direction are connected to each other. In this way, the actuating fluid 2b can move back and forth between the main flow channels 61a~61f of the fluid flow path.

[0081] The protrusion 64 is the portion of material remaining in the capillary sheet 30 that is not etched during the etching steps described below. In this embodiment, as shown in FIG9, the planar shape of the protrusion 64 (the shape at the position of the second body surface 31b of the capillary sheet 30) is rectangular.

[0082] The spacing between the protrusions 64 in the width direction (Y direction) of the main flow channels 61a and 61f is not uniform among the protrusions 64. That is, the spacing P1 of the protrusions 64 located on both sides of the width direction (Y direction) of each main flow channel 61a and 61f can be wider than the spacing P2 of the protrusions 64 located on both sides of the width direction (Y direction) of each main flow channel 61b to 61e (P1>P2). The spacing P1 and P2 of the protrusions 64 refer to the distance between the center of the protrusion 64 in the Y direction and the center of the adjacent protrusion 64 in the X direction, which is the distance measured in the Y direction. The spacing P1 of the protrusions 64 located on both sides of the main flow channels 61a and 61f in the Y direction can be, for example, more than 10 μm and less than 820 μm. The spacing P2 of the protrusions 64 located on both sides of the main flow channel 61b~61e in the Y direction can be, for example, 9 μm or more and 790 μm or less.

[0083] In this embodiment, the protrusions 64 are arranged in a staggered (interlaced) configuration. More specifically, the protrusions 64 of adjacent rows 63 in the Y direction are offset from each other in the X direction. This offset can be half of the arrangement spacing P4 of the protrusions 64 in the length direction (X direction) of the main flow channels 61a~61f of the liquid flow path. The width w5 (dimension in the Y direction) of the protrusions 64 can be, for example, more than 5 μm and less than 500 μm. Furthermore, the width w5 of the protrusions 64 can also be equal among the protrusions 64. Moreover, the width w5 of the protrusions 64 refers to the dimension in the second body surface 31b. The arrangement spacing P4 of the protrusions 64 can also be equal among the protrusions 64. The arrangement spacing P4 of the protrusions 64 refers to the distance between the center of the protrusion 64 in the X direction and the center of the adjacent protrusion 64 in the X direction. Furthermore, the arrangement of the protrusions 64 is not limited to a staggered configuration, but can also be arranged side by side. In this case, the protrusions 64 of adjacent protrusion rows 63 in the Y direction are also aligned in the X direction (see Figure 17).

[0084] The length L1 (dimension in the X direction) of the protrusion 64 can also be equal among the protrusions 64. Furthermore, the length L1 of the protrusion 64 is longer than the width w4 of the liquid flow path connecting groove 65 (L1>w4). Moreover, the length L1 of the protrusion 64 refers to the maximum dimension in the X direction of the second body surface 31b.

[0085] Furthermore, there are no particular restrictions on the materials constituting the lower sheet 10, upper sheet 20, and capillary sheet 30, as long as they have good thermal conductivity. For example, the lower sheet 10, upper sheet 20, and capillary sheet 30 may also contain copper or copper alloys. In this case, the thermal conductivity of each sheet 10, 20, and 30 can be increased, thereby improving the heat dissipation efficiency of the vapor chamber 1. Also, when using pure water as the actuating fluid 2a and 2b, corrosion can be prevented. Moreover, as long as the desired heat dissipation efficiency can be obtained and corrosion can be prevented, the sheets 10, 20, and 30 may also be made of other metal materials such as aluminum or titanium, or other metal alloy materials such as stainless steel.

[0086] Furthermore, the thickness t1 of the vapor chamber 1 shown in Figure 3 can be, for example, 100 μm or more and 2000 μm or less. By setting the thickness t1 of the vapor chamber 1 to 100 μm or more, the vapor flow path 50 is properly ensured, thereby allowing the vapor chamber 1 to function appropriately. On the other hand, by setting the thickness t1 to 2000 μm or less, the thickness t1 of the vapor chamber 1 can be prevented from becoming too thick.

[0087] The thickness t2 of the lower sheet 10 can be, for example, 25 μm or more and 500 μm or less. By setting the thickness t2 of the lower sheet 10 to 25 μm or more, the mechanical strength of the lower sheet 10 can be ensured. On the other hand, by setting the thickness t2 of the lower sheet 10 to 500 μm or less, the thickness t1 of the vapor chamber 1 can be suppressed from becoming thicker. Similarly, the thickness t3 of the upper sheet 20 can also be set in the same way as the thickness t2 of the lower sheet 10. The thickness t3 of the upper sheet 20 can also be different from the thickness t2 of the lower sheet 10.

[0088] The thickness t4 of the capillary sheet 30 can be, for example, 50 μm or more and 1000 μm or less. By setting the thickness t4 of the capillary sheet 30 to 50 μm or more, the vapor flow path 50 is properly secured, thereby allowing it to function properly as the vapor chamber 1. On the other hand, by setting it to 1000 μm or less, the thickness t1 of the vapor chamber 1 can be prevented from becoming too thick.

[0089] Next, the manufacturing method of the steam chamber 1 of this embodiment, which includes this configuration, will be described using Figures 10(a)-(c). Furthermore, Figures 10(a)-(c) show the same cross-section as the cross-sectional view in Figure 3.

[0090] Here, the manufacturing steps of the capillary sheet 30 will be explained first.

[0091] First, as shown in Figure 10(a), as a preparatory step, a flat metal sheet M containing a first material surface Ma and a second material surface Mb is prepared.

[0092] Following the preparation step, as an etching step, as shown in FIG10(b), the metal material sheet M is etched from the first material surface Ma and the second material surface Mb to form the vapor flow path 50 and the liquid flow path 60.

[0093] More specifically, a patterned resist film (not shown) is formed on the first material surface Ma and the second material surface Mb of the metal sheet M using photolithography. Then, the first material surface Ma and the second material surface Mb of the metal sheet M are etched through openings in the patterned resist film. This etches the first material surface Ma and the second material surface Mb of the metal sheet M into a pattern, forming the vapor flow path 50 and the liquid flow path 60 as shown in FIG10(b). Furthermore, the etching solution can be, for example, a ferric chloride-based etching solution such as an aqueous solution of ferric chloride, or a copper chloride-based etching solution such as an aqueous solution of copper chloride.

[0094] Regarding etching, the first material surface Ma and the second material surface Mb of the metal sheet M can be etched simultaneously. However, it is not limited to this; the etching of the first material surface Ma and the second material surface Mb can also be performed as different steps. Furthermore, the vapor flow path 50 and the liquid flow path 60 can be formed simultaneously by etching, or they can be formed by different steps.

[0095] Furthermore, during the etching step, the first material surface Ma and the second material surface Mb of the metal sheet M are etched, thereby obtaining the specific external contour shape shown in Figures 6 and 7. That is, the end edge of the capillary structure sheet 30 is formed.

[0096] In this way, the capillary sheet 30 of this embodiment can be obtained.

[0097] Following the fabrication step of the capillary sheet 30, as a joining step, as shown in FIG10(c), the lower sheet 10, the upper sheet 20, and the capillary sheet 30 are joined together. Furthermore, the lower sheet 10 and the upper sheet 20 can also be formed from rolled material having the desired thickness.

[0098] More specifically, firstly, the lower sheet 10, the capillary sheet 30, and the upper sheet 20 are sequentially laminated. In this case, the first body surface 31a of the capillary sheet 30 is aligned with the second lower sheet surface 10b of the lower sheet 10, and the first upper sheet surface 20a of the upper sheet 20 is aligned with the second body surface 31b of the capillary sheet 30. At this time, the sheets 10, 20, and 30 are aligned using the alignment holes 12 of the lower sheet 10 (see Figure 4), the alignment holes 35 of the capillary sheet 30 (see Figures 6 and 7), and the alignment holes 22 of the upper sheet 20 (see Figure 5).

[0099] Subsequently, the lower sheet 10, the capillary sheet 30, and the upper sheet 20 are temporarily fixed. For example, the sheets 10, 20, and 30 can be temporarily fixed by point resistance welding, or by laser welding.

[0100] Subsequently, the lower sheet 10, capillary sheet 30, and upper sheet 20 are permanently bonded together by diffusion bonding. Diffusion bonding refers to the following bonding method: First, the lower sheet 10 and capillary sheet 30 are brought into close contact, and the capillary sheet 30 and upper sheet 20 are brought into close contact. Then, in a controlled atmosphere such as a vacuum or inert gas, the lower sheet 10, capillary sheet 30, and upper sheet 20 are pressurized and heated in the lamination direction, and bonded by the diffusion of atoms generated on the bonding surface. Diffusion bonding involves heating the materials of each sheet 10, 20, and 30 to a temperature close to their melting point, but below the melting point, thus preventing the sheets 10, 20, and 30 from melting and deforming. More specifically, the first body surface 31a of the frame portion 32 and each island portion 33 of the capillary sheet 30 diffusely bonds to the second lower sheet surface 10b of the lower sheet 10. Furthermore, the second body surface 31b of the frame portion 32 and each island portion 33 of the capillary sheet 30 diffusely bonds to the first upper sheet surface 20a of the upper sheet 20. In this manner, the sheets 10, 20, and 30 are diffusely bonded, forming a sealed space 3 with a vapor flow path 50 and a liquid flow path 60 between the lower sheet 10 and the upper sheet 20.

[0101] After the joining step, the actuating fluid 2b is injected into the sealed space 3 from the injection section 4.

[0102] Subsequently, the injection flow path 37 is sealed. For example, the injection section 4 can be partially melted to seal the injection flow path 37. In this way, the communication between the sealed space 3 and the outside is cut off, and the actuating fluid 2b is sealed into the sealed space 3, thereby preventing the actuating fluid 2b in the sealed space 3 from leaking to the outside.

[0103] The steam chamber 1 of this embodiment can be obtained in the manner described above.

[0104] Next, the operation method of the vapor chamber 1, i.e. the cooling method of device D, will be explained.

[0105] The vapor chamber 1 obtained in the above manner is disposed within the casing H of an electronic device such as a mobile terminal. Furthermore, a device D, such as a CPU, serving as a cooling device, is mounted on the second upper sheet surface 20b of the upper sheet 20 (or, the vapor chamber 1 is mounted on the device D). The actuating fluid 2b within the sealed space 3 adheres to the walls of the sealed space 3 by means of its surface tension, namely the first wall surface 53a and the second wall surface 54a of the vapor passage 51, the wall surface 62 of the main liquid flow channel 61a~61f of the liquid flow channel 60, and the wall surface of the liquid flow channel connecting channel 65. Additionally, the actuating fluid 2b may also adhere to the portion of the lower sheet surface 10b of the lower sheet 10 that is exposed in the vapor passage 51. Furthermore, the actuating fluid 2b may also adhere to the portion of the upper sheet 20 surface 20a that is exposed in the vapor passage 51, the main liquid flow channel 61a~61f and the liquid flow channel connecting channel 65.

[0106] If device D heats up in this state, the actuating fluid 2b in the evaporation region SR (see Figures 6 and 7) receives heat from device D. The received heat is absorbed as latent heat, causing the actuating fluid 2b to evaporate (vaporize), generating actuating vapor 2a. Most of the generated actuating vapor 2a diffuses within the vapor passages 51 that constitute the sealed space 3 (see the solid arrows in Figure 6). The actuating vapor 2a in each vapor passage 51 leaves the evaporation region SR, and most of the actuating vapor 2a is transported to the relatively cooler condensation region CR (the right side of Figures 6 and 7). In the condensation region CR, the actuating vapor 2a is mainly cooled by dissipating heat to the lower sheet 10. The heat received by the lower sheet 10 from the actuating vapor 2a is transferred to the external atmosphere via the outer casing member Ha (see Figure 3).

[0107] The actuating vapor 2a dissipates heat to the lower sheet 10 in the condensation zone CR, and condenses due to the latent heat absorbed in the evaporation zone SR, generating an actuating liquid 2b. The generated actuating liquid 2b adheres to the first wall surface 53a and the second wall surface 54a of each vapor passage 51, the second lower sheet surface 10b of the lower sheet 10, and the first upper sheet surface 20a of the upper sheet 20. Here, the actuating liquid 2b continues to evaporate in the evaporation zone SR. Therefore, the actuating liquid 2b in the area outside the evaporation zone SR (i.e., the condensation zone CR) of the liquid flow path 60 is transported towards the evaporation zone SR by the capillary action of the main flow channels 61a~61f of each liquid flow path (see the dashed arrow in Figure 6). In this way, the actuating fluid 2b attached to each vapor passage 51, the second lower sheet surface 10b, and the first upper sheet surface 20a moves to the liquid flow path section 60 and enters the main liquid flow path channels 61a-61f through the liquid flow path connecting groove 65. In this manner, the actuating fluid 2b fills each main liquid flow path channel 61a-61f and each liquid flow path connecting groove 65. Therefore, the filled actuating fluid 2b obtains a propulsive force towards the evaporation zone SR through the capillary action of each main liquid flow path channel 61a-61f, thereby smoothly transporting it towards the evaporation zone SR.

[0108] In the liquid flow path section 60, each liquid flow path main channel 61a-61f is connected to the adjacent liquid flow path main channels 61a-61f via a corresponding liquid flow path connecting channel 65. This allows the actuating fluid 2b to flow between the adjacent liquid flow path main channels 61a-61f, preventing it from drying out within these channels. Therefore, a capillary effect is applied to the actuating fluid 2b within each liquid flow path main channel 61a-61f, and the actuating fluid 2b is smoothly transported towards the evaporation zone SR.

[0109] The actuating fluid 2b, having reached the evaporation zone SR, receives heat again from the device D and evaporates. The actuating vapor 2a evaporated from the actuating fluid 2b moves through the liquid flow path connecting groove 65 within the evaporation zone SR to the vapor passage 51 with a larger cross-sectional area, where it diffuses. In this way, the actuating fluids 2a and 2b undergo repeated phase changes, i.e., evaporation and condensation, while simultaneously flowing back within the sealed space 3, transporting and releasing heat from the device D. As a result, the device D is cooled.

[0110] Furthermore, there exists a situation where, during the transport of the actuating fluid 2b from the main liquid flow channels 61a and 61f closest to the vapor flow channel 50 (vapor passage 51) toward the other main liquid flow channels 61b to 61e, the flow of the actuating fluid 2b may stagnate. In this embodiment, the widths w3a and w3f of the main liquid flow channels 61a and 61f are made wider than the widths w3b and w3e of the main liquid flow channels 61b to 61e. Therefore, when the flow of the actuating fluid 2b from the main liquid flow channels 61a and 61f located on the outer side of the width direction of the liquid flow channel 60 toward the main liquid flow channels 61b to 61e located on the inner side of the width direction stagnates, the condensed actuating fluid 2b from the vapor flow channel 50 can be stored in the wider main liquid flow channels 61a and 61f. Therefore, the actuating fluid 2b can be smoothly condensed from the vapor flow path 50 towards the liquid flow path 60. As a result, the pressure difference between the evaporation zone SR and the condensation zone CR can be maintained, thereby suppressing the reduction of the cooling capacity of the vapor chamber 1.

[0111] Furthermore, the widths w3a and w3f of the main flow channels 61a and 61f located on the outer side of each liquid flow path 60 in the width direction are wider than the widths w3b and w3e of the main flow channels 61b and 61e located on the inner side in the width direction. Therefore, the capillary force in the main flow channels 61b and 61e located on the inner side in the width direction can be increased. This allows for easy transport of the actuating fluid 2b towards the evaporation zone SR. On the other hand, by making the widths w3a and w3f of the main flow channels 61a and 61f located on the outer side of each liquid flow path 60 in the width direction wider, a large amount of actuating fluid 2b can be transported towards the evaporation zone SR.

[0112] Thus, according to this embodiment, the widths w3a and w3f of the main liquid flow channels 61a and 61f closest to the vapor flow path 50 (vapor passage 51) are wider than the widths w3b and w3e of the other main liquid flow channels 61b to 61e. Therefore, when the flow of the actuating fluid 2b from the main liquid flow channels 61a and 61f located on the outer side of the width direction of each liquid flow path 60 toward the main liquid flow channels 61b to 61e located on the inner side in the width direction stops, the actuating fluid 2b can be stored in the wider main liquid flow channels 61a and 61f. As a result, the actuating fluid 2b can be smoothly condensed from the vapor flow path 50 toward the liquid flow path 60, thereby improving the cooling capacity of the vapor chamber 1.

[0113] Furthermore, according to this embodiment, the depth h1a of the main liquid flow channels 61a and 61f closest to the vapor flow channel 50 (vapor passage 51) is deeper than the depth h1b of the other main liquid flow channels 61b to 61e. Therefore, when the flow of the actuating fluid 2b from the main liquid flow channels 61a and 61f located on the outer side of the width direction of each liquid flow channel 60 toward the main liquid flow channels 61b to 61e located on the inner side in the width direction stops, the actuating fluid 2b can be stored in the deeper main liquid flow channels 61a and 61f. Thus, the actuating fluid 2b can be smoothly condensed from the vapor flow channel 50 toward the liquid flow channel 60, thereby improving the cooling capacity of the vapor chamber 1.

[0114] Furthermore, according to this embodiment, the spacing P1 of the protrusions 64 on both sides of the main liquid flow channels 61a and 61f closest to the vapor flow channel 50 (vapor passage 51) in the width direction is wider than the spacing P2 of the protrusions 64 on both sides of the other main liquid flow channels 61b to 61e in the width direction. This prevents the width w5 of the protrusions 64 adjacent to the main liquid flow channels 61a and 61f from becoming excessively narrow, thus suppressing a decrease in the bonding strength between the protrusions 64 and the upper sheet 20.

[0115] (Example of variation) Next, various variations of this embodiment will be described with reference to Figures 11 to 17. Figures 11 to 17 are diagrams showing the capillary sheet 30 of the variations. In Figures 11 to 17, the same symbols are used for the parts with the same shape as those shown in Figures 1 to 10, and detailed descriptions are omitted.

[0116] (Example 1 of the variations) In the above embodiment, an example in which the width w5 of the protrusion 64 is equal among the protrusions 64 has been described. However, it is not limited to this, and the width of the protrusion 64 may also be uneven among the protrusions 64.

[0117] For example, as in the first modification shown in FIGS. 11 and 12, the widths w5a to w5c of the convex portions 64 are not equal between the respective convex portions 64. For example, the width w5a of the convex portion 64a located on the inner side in the Y direction (the side of the main liquid flow path grooves 61b and 61e) with respect to the main liquid flow path grooves 61a and 61f of the liquid flow path may be narrower than the width w5b of the convex portion 64b located on the inner side in the width direction of each liquid flow path portion 60 compared to the above-mentioned convex portion 64a (w5a < w5b). In this case, the width w5a of the convex portion 64a may be, for example, 5 μm or more and 380 μm or less, and the width w5b of the convex portion 64b may be, for example, 10 μm or more and 400 μm or less. Furthermore, the width w5c of the convex portion 64c located on the outer side in the Y direction (the side of the vapor flow path portion 50) with respect to the main liquid flow path grooves 61a and 61f may be the same as the width w5a of the convex portion 64a or the width w5b of the convex portion 64b, or may be different from w5a or w5b.

[0118] Also, the center-to-center distances P3 in the width direction (Y direction) of the respective main liquid flow path grooves 61a to 61f may be equal to each other. That is, the distances between the main liquid flow path grooves 61a and 61b, between the main liquid flow path grooves 61b and 61c, between the main liquid flow path grooves 61d and 61e, and between the main liquid flow path grooves 61e and 61f are equal to each other. In this case, the center-to-center distance P3 may be, for example, 5 μm or more and 500 μm or less. The center-to-center distance P3 is the shortest distance between the center positions in the width direction (Y direction) of the adjacent main liquid flow path grooves 61a to 61f, and refers to the distance measured in the Y direction.

[0119] In this modification, the widths w3a and w3f of the main liquid flow path grooves 61a and 61f located on the outer side in the width direction of each liquid flow path portion 60 are wider than the widths w3b to w3e of the main liquid flow path grooves 61b to 61e located on the inner side in the width direction. Thereby, when the flow of the working fluid 2b stagnates from the main liquid flow path grooves 61a and 61f located on the outer side in the width direction of each liquid flow path portion 60 toward the main liquid flow path grooves 61b to 61e located on the inner side in the width direction, the working fluid 2b can also be stored in the wider main liquid flow path grooves 61a and 61f. As a result, the working fluid 2b can be smoothly condensed from the vapor flow path portion 50 toward the liquid flow path portion 60, and thus the cooling ability of the vapor chamber 1 can be improved.

[0120] (Second modification) In the above embodiments, the following example is described: the widths w3a and w3f of the main liquid flow channels 61a and 61f located on the outer side of each liquid flow channel 60 in the width direction are equal, and the widths w3b and w3e of the main liquid flow channels 61b to 61e located on the inner side in the width direction are equal. However, it is not limited to this; the widths of the main liquid flow channels 61a to 61f can also vary from the main liquid flow channels 61a and 61f closest to the vapor flow channel 50 (vapor passage 51) towards the main liquid flow channels 61c and 61d located on the inner side in the width direction of each liquid flow channel 60, gradually narrowing.

[0121] For example, in the second variation shown in Figures 13 and 14, among the plurality of liquid flow path main channels 61a-61f, the widths w3a and w3f of the liquid flow path main channels 61a and 61f closest to the vapor flow path section 50 (vapor passage 51) are the widest. Furthermore, the widths w3c and w3d of the innermost liquid flow path main channels 61c and 61d are the narrowest. The widths w3b and w3e of the other liquid flow path main channels 61b and 61e are the lengths between the widths w3a and w3f of the liquid flow path main channels 61a and 61f and the widths w3c and w3d of the liquid flow path main channels 61c and 61d. That is, the relationship w3a, w3f > w3b, w3e > w3c, w3d holds true.

[0122] In Figures 13 and 14, the widths w3a and w3f of the main flow channels 61a and 61f located on the outer side of each liquid flow channel 60 in the width direction are equal to each other, and the widths w3c and w3d of the main flow channels 61c and 61d located on the inner side of each liquid flow channel 60 in the width direction are equal to each other. Furthermore, the widths w3b and w3e of the main flow channels 61b and 61e located between these equal sides are equal to each other. That is, the relationship w3a=w3f>w3b=w3e>w3c=w3d holds true. However, this is not limited to this; the widths w3a and w3f of the main flow channels 61a and 61f may also be different from each other. Similarly, the widths w3c and w3d of the main flow channels 61c and 61d may also be different from each other. Furthermore, the widths w3b and w3e of the main flow channels 61b and 61e in the liquid flow path can also be different from each other.

[0123] The widths w3a and w3f of the main flow channels 61a and 61f are preferably 1.1 to 1.6 times the widths w3b and w3e of the main flow channels 61b and 61e adjacent to them in the width direction. Furthermore, the widths w3b and w3e of the main flow channels 61b and 61e are preferably 1.1 to 1.6 times the widths w3c and w3d of the main flow channels 61c and 61d adjacent to them in the width direction. The widths w3a and w3f of the main flow channels 61a and 61f can, for example, be 5.5 μm to 320 μm. The widths w3b and w3e of the main flow channels 61b and 61e can, for example, be 3.5 μm to 290 μm. The widths w3c and w3d of the main flow channels 61c and 61d in the liquid flow path can be, for example, above 2.2 μm and below 260 μm.

[0124] In Figure 13, the depths h1a, h1b, and h1c of the main flow channels 61a to 61f are not all equal among them. Specifically, the depth h1a of the main flow channels 61a and 61f located on the outer side of the width direction of each liquid flow section 60 may be deeper than the depth h1b of the main flow channels 61b and 61e adjacent to their inner side in the width direction. Furthermore, the depth h1b of the main flow channels 61b and 61e may also be deeper than the depth h1c of the main flow channels 61c and 61d adjacent to their inner side in the width direction (h1a>h1b>h1c). In this case, the depth h1a of the main flow channels 61a and 61f are equal to each other, and the depth h1b of the main flow channels 61b and 61e are equal to each other. Furthermore, the depth h1c of the main flow channels 61c and 61d is equal to each other. The depth h1a of the main flow channels 61a and 61f can be, for example, set to 3.5 μm or more and 240 μm or less. The depth h1b of the main flow channels 61b and 61e can be, for example, set to 3.3 μm or more and 200 μm or less. The depth h1c of the main flow channels 61c and 61d can be, for example, set to 3 μm or more and 150 μm or less. However, this is not a limitation; the depth h1a of the main flow channels 61a and 61f can also be different from each other, and the depth h1b of the main flow channels 61b and 61e can also be different from each other. Furthermore, the depth h1c of the main flow channels 61c and 61d can also be different from each other.

[0125] Thus, according to the second variation, the width of the main liquid flow channels 61a-61f gradually narrows from the main liquid flow channels 61a and 61f closest to the vapor flow channel 50 toward the main liquid flow channels 61c and 61d located inside the width direction of each liquid flow channel 60. Therefore, when the flow of the actuating fluid 2b from the main liquid flow channels 61a and 61f located outside the width direction of each liquid flow channel 60 toward the main liquid flow channels 61c and 61d located inside the width direction stops, the condensed actuating fluid 2b from the vapor flow channel 50 can be stored in the wider main liquid flow channels 61a and 61f. Therefore, the actuating fluid 2b can be smoothly condensed from the vapor flow channel 50 toward the liquid flow channel 60.

[0126] (Example 3) In the above embodiment, the following example is described: the widths w3a and w3f of the main liquid flow channels 61a and 61f located on the outer side of each liquid flow channel 60 in the width direction are equal, and the widths w3b and w3e of the main liquid flow channels 61b to 61e located on the inner side of each liquid flow channel 60 in the width direction are equal. However, this is not a limitation; the widths of the main liquid flow channels 61a and 61f closest to the vapor flow channel 50 (vapor passage 51) and the widths of the second main liquid flow channels 61b and 61c closest to the vapor flow channel 50 (vapor passage 51) may also be equal.

[0127] For example, in the third variation shown in Figures 15 and 16, among the plurality of liquid flow path main channels 61a-61f, the widths w3a and w3f of the liquid flow path main channels 61a and 61f closest to the vapor flow path section 50 (vapor passage 51) and the widths w3b and w3e of the liquid flow path main channels 61b and 61e closest to the vapor flow path section 50 (vapor passage 51) are the widest. Furthermore, the widths w3c and w3d of the liquid flow path main channels 61c and 61d located at the innermost edge in the width direction are the narrowest. That is, the relationship w3a, w3b, w3e, w3f > w3c, w3d holds true.

[0128] In Figures 15 and 16, the widths w3a, w3b, w3e, and w3f of the main flow channels 61a, 61b, 61e, and 61f are all equal, and the widths w3c and w3d of the main flow channels 61c and 61d are also equal. That is, the relationship w3a=w3b=w3e=w3f>w3c=w3d holds. However, this is not a limitation; the widths w3a, w3b, w3e, and w3f of the main flow channels 61a, 61b, 61e, and 61f can also be different. Furthermore, the widths w3c and w3d of the main flow channels 61c and 61d can also be different. Furthermore, in this variation example, the following scenario is illustrated: among the plurality of liquid flow path main channels, the widths w3a, w3b, w3e, and w3f of two pairs (four) of the liquid flow path main channels 61a, 61b, 61e, and 61f, starting from the side closest to the steam flow path section 50 (steam passage 51), are identical and the widest, but this is not a limitation. Alternatively, among the plurality of liquid flow path main channels, the widths of three pairs (six) or more of the liquid flow path main channels, starting from the side closest to the steam flow path section 50 (steam passage 51), may be identical and the widest. For example, in the case of eight liquid flow path main channels, the widths of three pairs (six) of the liquid flow path main channels, starting from the side closest to the steam flow path section 50 (steam passage 51), may be identical and the widest.

[0129] Thus, according to the third variation, two pairs (four) of wider liquid flow path main channels 61a, 61b, 61e, and 61f are provided, resulting in a particularly large area for storing the actuating fluid 2b. Therefore, when the flow of the actuating fluid 2b from the liquid flow path main channels 61a, 61b, 61e, and 61f located on the outer side of the width direction of each liquid flow path 60 toward the liquid flow path main channels 61c and 61d located on the inner side of the width direction stops, more of the condensed actuating fluid 2b from the vapor flow path 50 can be stored in the wider liquid flow path main channels 61a, 61b, 61e, and 61f.

[0130] (Example 4) In the above embodiment, an example of the protrusions 64 being configured in a staggered shape has been described. However, it is not limited to this; as shown in FIG17, the protrusions 64 can also be configured in a grid pattern. Specifically, when the center point located in the X and Y directions of the protrusions 64 is set as the center point Pc, the center points Pc of a plurality of protrusions 64 are configured in a grid pattern. That is, the center points Pc of a plurality of protrusions 64 are arranged parallel in the X and Y directions, respectively. In this case, when the flow of the actuating fluid 2b from the main liquid flow channels 61a, 61f located on the outer side of the width direction of each liquid flow channel 60 toward the main liquid flow channels 61c, 61d located on the inner side of the width direction stops, more of the condensed actuating fluid 2b from the vapor flow channel 50 can be stored in the wider liquid flow channel connecting channel 65.

[0131] (Second Implementation) Next, the second embodiment will be described with reference to Figures 18 to 26. Figures 18 to 26 are diagrams illustrating the second embodiment. In Figures 18 to 26, the same symbols are used for the parts that have the same shape as those shown in Figures 1 to 17, and detailed descriptions are omitted.

[0132] As shown in Figure 18, the capillary sheet 30 of this embodiment has a first body surface 31a, a second body surface 31b, a vapor flow path 50, and a liquid flow path 60. The liquid flow path 60 is disposed on the second body surface 31b of the capillary sheet 30. The liquid flow path 60 is mainly for the passage of the actuating fluid 2b. This liquid flow path 60 constitutes a part of the aforementioned sealed space 3 and communicates with the vapor flow path 50. The liquid flow path 60 is configured as a capillary structure (capillary structure) for transporting the actuating fluid 2b to the evaporation zone SR. In this embodiment, the liquid flow path 60 is disposed on the second body surface 31b of each island portion 33 of the capillary sheet 30. The liquid flow path 60 may also be formed throughout the entire second body surface 31b of each island portion 33.

[0133] As shown in Figure 19, the liquid flow path section 60 has a plurality of main liquid flow path channels 61 through which the actuating fluid 2b passes and arranged in parallel with each other, and a plurality of liquid flow path connecting channels 65 communicating with the main liquid flow path channels 61. Furthermore, in the example shown in Figure 19, each island section 33 includes six main liquid flow path channels 61, but it is not limited to this. The number of main liquid flow path channels 61 included in each island section 33 is arbitrary; for example, it can be more than three and less than twenty.

[0134] As shown in Figure 19, each liquid flow path main channel 61 is formed to extend along the length direction (X direction) of the island portion 33. A plurality of liquid flow path main channels 61 are arranged parallel to each other. Furthermore, when the island portion 33 is curved in plan view, each liquid flow path main channel 61 may also extend in a curved shape along the curvature direction of the island portion 33. That is, each liquid flow path main channel 61 may not necessarily be formed in a straight line, and may not extend parallel to the X direction.

[0135] The main liquid flow channel 61 has a smaller cross-sectional area than the vapor passage 51 of the vapor flow channel 50, primarily for the flow of the actuating liquid 2b via capillary action. The main liquid flow channel 61 is configured to transport the actuating liquid 2b, which is condensed from the self-actuating vapor 2a, to the evaporation zone SR. Each main liquid flow channel 61 is spaced apart from the others in the width direction (Y direction).

[0136] The main liquid flow channel 61 is formed by etching from the second body surface 31b of the capillary sheet 30 during the etching step of fabricating the capillary sheet 30. As shown in FIG18, the main liquid flow channel 61 has a curved wall surface 62. This wall surface 62 defines the main liquid flow channel 61 and is curved in a shape that bulges towards the first body surface 31a. Furthermore, in the cross-section shown in FIG18, the radius of curvature of each wall surface 62 is preferably smaller than the radius of curvature of the second wall surface 54a of the vapor passage 51.

[0137] In Figure 19, the widths w3 of all the main flow channels 61 are equal. In this case, the cross-sectional shapes (depth, width, etc.) of the plurality of main flow channels 61 can also be symmetrical with respect to the centerline of the width direction (Y direction) of the island portion 33. However, this is not a limitation, and the widths w3 of the main flow channels 61 can also be different. Furthermore, the width w3 of the main flow channels 61 refers to the length in the direction perpendicular to the length direction of the island portion 33, which in this case refers to the dimension in the Y direction. Also, the width w3 of the main flow channels 61 refers to the dimension in the second body surface 31b. Furthermore, the width w3 of the main flow channels 61 can be, for example, 2.2 μm or more and 320 μm or less.

[0138] Furthermore, as shown in Figure 18, the depth h1 of the main flow channel 61 is uniform across all main flow channels 61. However, this is not a limitation; the depth h1 of the main flow channel 61 may also vary among the main flow channels 61. For example, the depth h1 of the main flow channel 61 may be set to between 3 μm and 240 μm. Moreover, the depth h1 of the main flow channel 61 is the distance measured from the second body surface 31b in a direction perpendicular to the second body surface 31b; in this case, it is a dimension in the Z direction. Also, depth h1 refers to the depth of the deepest part of the main flow channel 61.

[0139] As shown in Figure 19, each liquid flow path connecting groove 65 extends in a direction different from the X direction. In this embodiment, each liquid flow path connecting groove 65 is formed to extend in the Y direction and is formed perpendicular to the main liquid flow path groove 61. Several liquid flow path connecting grooves 65 are arranged in such a way that adjacent main liquid flow path grooves 61 are connected to each other. Other liquid flow path connecting grooves 65 are arranged in such a way that the vapor flow path 50 (vapor passage 51) is connected to the main liquid flow path groove 61 closest to the vapor flow path 50. That is, the liquid flow path connecting groove 65 extends from the end side of the island portion 33 in the Y direction to the main liquid flow path groove 61 adjacent to that end. In this way, the vapor passage 51 of the vapor flow path 50 is connected to the main liquid flow path groove 61.

[0140] The liquid flow path connecting groove 65 has a smaller flow path cross-sectional area than the vapor passage 51 of the vapor flow path section 50, so as to mainly allow the actuating liquid 2b to flow by capillary action. Each liquid flow path connecting groove 65 can also be arranged at equal intervals along the length direction (X direction) of the island section 33.

[0141] The liquid flow path connecting groove 65, like the main liquid flow path groove 61, is formed by etching and has a curved wall surface (not shown), similar to the main liquid flow path groove 61. As shown in Figure 19, the width w4 (dimension in the X direction) of the liquid flow path connecting groove 65 can be set to 5 μm or more and 300 μm or less. The depth of the liquid flow path connecting groove 65 can be set to 3 μm or more and 240 μm or less.

[0142] The main flow channel 61 includes a flow channel intersection 66 that communicates with the flow channel connecting channel 65. At the flow channel intersection 66, the main flow channel 61 and the flow channel connecting channel 65 are connected in a T-shape. In this case, at the flow channel intersection 66, one main flow channel 61 communicates with one side (e.g., the upper side in FIG. 19) of the flow channel connecting channel 65. This prevents the other side (e.g., the lower side in FIG. 19) of the flow channel connecting channel 65 from communicating with the main flow channel 61 at the flow channel intersection 66. Therefore, at the flow channel intersection 66, the wall 62 of the main flow channel 61 is not cut open on both sides in the Y direction, allowing one side of the wall 62 to remain intact. Therefore, at the liquid flow path intersection 66, the actuating liquid 2b in the main liquid flow path channel 61 can also be given a capillary effect, thereby suppressing the reduction of the propulsion force of the actuating liquid 2b toward the evaporation region SR at the liquid flow path intersection 66.

[0143] As shown in Figure 19, protrusions 63 are provided between adjacent main flow channels 61 in the liquid flow path section 60. Furthermore, the example shown in Figure 19 illustrates a case where each island section 33 contains 7 rows of protrusions 63, but this is not a limitation. The number of protrusions 63 in each island section 33 is arbitrary; for example, it can be 3 to 20 rows.

[0144] As shown in Figure 19, each row of protrusions 63 is formed to extend along the length direction (X direction) of the island portion 33. A plurality of rows of protrusions 63 are arranged parallel to each other. Furthermore, when the island portion 33 is curved in plan view, each row of protrusions 63 may also extend in a curved shape along the curvature direction of the island portion 33. That is, each row of protrusions 63 may not necessarily be formed in a straight line, and may not extend parallel to the X direction. The rows of protrusions 63 are spaced apart from each other in the width direction (Y direction).

[0145] Each row of protrusions 63 includes a plurality of protrusions 64a to 64g (liquid flow path protrusions) arranged along the X direction. Protrusions 64a to 64g are arranged from the positive side of the Y direction towards the negative side of the Y direction, in the order of protrusion 64a, protrusion 64b, protrusion 64c, protrusion 64d, protrusion 64e, protrusion 64f, and protrusion 64g. Protrusions 64a and 64g are located closest to the vapor flow path 50 (vapor passage 51) and are located on the outermost side of the liquid flow path 60 in the Y direction. Protrusion 64d is located furthest from the vapor flow path 50 (vapor passage 51) and is located on the innermost side of the liquid flow path 60 in the Y direction.

[0146] The convex portions 64a to 64g are provided in the liquid flow path portion 60, protrude from the main liquid flow path groove 61 and the liquid flow path connection groove 65, and abut against the upper sheet 20. Each of the convex portions 64a to 64g is formed in a rectangular shape such that the X direction is the longitudinal direction in plan view. Between the convex portions 64a to 64g adjacent to each other in the Y direction, the main liquid flow path groove 61 is respectively arranged. Between the convex portions 64a to 64g adjacent to each other in the X direction, the liquid flow path connection groove 65 is respectively arranged. The liquid flow path connection groove 65 is formed to extend in the Y direction, so as to connect the main liquid flow path grooves 61 adjacent to each other in the Y direction. Thereby, the working fluid 2b can travel between these main liquid flow path grooves 61.

[0147] The convex portions 64a to 64g are portions where the material of the capillary structure sheet 30 remains without being etched in the etching step of manufacturing the capillary structure sheet 30. In the present embodiment, as shown in FIG. 19, the planar shape of the convex portions 64a to 64g (the shape at the position of the second body surface 31b of the capillary structure sheet 30) is in a rectangular shape.

[0148] As shown in FIG. 19, the widths of the convex portions 64a to 64g are not all equal among the convex portions 64a to 64g. Specifically, the widths of the convex portions 64a, 64g (hereinafter, also referred to as the convex portions 64a, 64g) of the convex portion row 63 closest to the vapor flow path portion 50 (vapor passage 51) are narrower than the widths of the convex portions 64b to 64f (hereinafter, also referred to as the convex portions 64b to 64f) of the other convex portion rows 63. That is, when the widths of the convex portions 64a to 64g are respectively set as w5a to w5g, the widths w5a, w5g of the convex portions 64a, 64g are narrower than the widths w5b to w5f of the convex portions 64b to 64f (w5a, w5g < w5b to w5f). Further, in the present embodiment, the widths of the plurality of convex portions included in the same convex portion row 63 are equal to each other.

[0149] In FIG. 19, the widths w5a, w5g of the convex portions 64a, 64g of the convex portion row 63 located outside the width direction of each liquid flow path portion 60 are equal to each other, and the widths w5b to w5f of the convex portions 64b to 64f of the convex portion row 63 located inside the width direction of each liquid flow path portion 60 are equal to each other. That is, the relationship of w5a = w5g < w5b = w5c = w5d = w5e = w5f holds. However, it is not limited thereto, and the widths w5a, w5g of the convex portions 64a, 64g may be different from each other. Also, the widths w5b to w5f of the convex portions 64b to 64f may be different from each other. However, preferably, the wider one of the widths w5a, w5g of the convex portions 64a, 64g is narrower than the narrowest one of the widths w5b to w5f of the convex portions 64b to 64f.

[0150] The widths w5a and w5g of the convex portions 64a and 64g are preferably 0.3 times or more and 0.95 times or less of the widths w5b to w5f of the convex portions 64b to 64f. By the magnification being 0.3 times or more, the shapes of the convex portions 64a and 64g can be stably produced. On the other hand, by the magnification being 0.95 times or less, the evaporation and condensation of the working fluid 2b can be smoothly performed between the steam passage 51 and the main flow channel 61 of the liquid flow path. Also, the working fluid 2b can be easily made to flow from the main flow channel 61 of the liquid flow path located on the outer side in the width direction of each liquid flow path portion 60 to the main flow channel 61 of the liquid flow path located on the inner side in the width direction.

[0151] Furthermore, the widths w5a to w5g of the convex portions 64a to 64g refer to the lengths in the direction perpendicular to the length direction of the island portion 33, and in this case, refer to the dimensions in the Y direction. Also, the widths w5a to w5g of the convex portions 64a to 64g refer to the dimensions in the second body surface 31b. Furthermore, the widths w5a and w5g of the convex portions 64a and 64g located on the outer side in the width direction of each liquid flow path portion 60 can be, for example, 1.5 μm or more and 475 μm or less. The widths w5b to w5f of the convex portions 64b to 64f located on the inner side in the width direction of each liquid flow path portion 60 can be, for example, 5 μm or more and 500 μm or less.

[0152] The arrangement pitches of the convex portions 64a to 64g in the width direction (Y direction) of the convex portions 64a to 64g are not equal among the convex portions 64a to 64g. That is, the arrangement pitch P1 between the convex portion 64a (64g) closest to the steam flow path portion 50 (steam passage 51) and the convex portion 64b (64f) adjacent to the convex portion 64a in the Y direction is narrower than the arrangement pitch P2 between the other convex portions 64b to 64f (P1 < P2). Here, the arrangement pitch of the convex portions 64a to 64g is the interval between the centers in the Y direction of the convex portions 64a to 64g and the centers in the Y direction of the adjacent convex portions 64a to 64g, and refers to the distance measured in the Y direction. The arrangement pitch P1 between the convex portion 64a (64g) and the convex portion 64b (64f) can be, for example, 30 μm or more and 800 μm or less. The arrangement pitch P2 between the other convex portions 64b to 64f can be, for example, 35 μm or more and 1000 μm or less. Furthermore, and not limited to this, the arrangement pitches in the width direction of the convex portions 64a to 64g can also be all equal among the convex portions 64a to 64g.

[0153] In this embodiment, the protrusions 64a-64g are arranged in a staggered (interlaced) configuration. More specifically, the protrusions 64a-64g of adjacent rows 63 in the Y direction are offset from each other in the X direction. This offset can be half the spacing between the protrusions 64a-64g in the X direction. Furthermore, the arrangement of the protrusions 64a-64g is not limited to a staggered configuration; they can also be arranged side by side. In this case, the protrusions 64a-64g of adjacent rows 63 in the Y direction are also aligned in the X direction (see Figure 26).

[0154] The length L1 (dimension in the X direction) of the protrusions 64a to 64g can also be equal among the protrusions 64a to 64g. Furthermore, the length L1 of the protrusions 64a to 64g is longer than the width w4 of the liquid flow path connecting groove 65 (L1>w4). Moreover, the length L1 of the protrusions 64a to 64g refers to the maximum dimension in the X direction of the second body surface 31b.

[0155] The steam chamber 1 and capillary sheet 30 in this embodiment can be manufactured in the same manner as in the first embodiment (see Figure 10).

[0156] Next, the function of this embodiment, which includes this configuration, will be described.

[0157] In the evaporation zone SR, the actuating vapor 2a generated by the actuating liquid 2b moves from the liquid flow path 60 toward the vapor passage 51. At this time, the actuating vapor 2a flows out of the main liquid flow path channel 61 through the liquid flow path connecting channel 65 adjacent to the protrusions 64a and 64g on the outer side of each liquid flow path 60 in the width direction, and then into the vapor passage 51. On the other hand, in the condensation zone CR, the actuating liquid 2b generated by the actuating vapor 2a moves from the vapor passage 51 toward the liquid flow path 60. At this time, the actuating liquid 2b enters the main liquid flow path channel 61 through the liquid flow path connecting channel 65 adjacent to the protrusions 64a and 64g on the outer side of each liquid flow path 60 in the width direction.

[0158] In this embodiment, among the plurality of protrusions 64a-64g, the widths w5a and w5g of the protrusions 64a and 64g closest to the steam passage 51 are narrower than the widths w5b and w5f of the protrusions 64b-64f of the other protrusion rows 63. Therefore, the length (distance in the Y direction) of the liquid flow path connecting groove 65 adjacent to the protrusions 64a and 64g is shorter, and the flow resistance of the liquid flow path connecting groove 65 is lower. This suppresses the flow resistance on the outer side of the liquid flow path portion 60 in the width direction (Y direction), allowing the actuating vapor 2a or actuating liquid 2b to flow smoothly between the steam passage 51 and the liquid flow path portion 60. As a result, the condensation of the actuating vapor 2a or the evaporation of the actuating liquid 2b between the steam passage 51 and the liquid flow path portion 60 can proceed smoothly, thereby improving the cooling capacity of the steam chamber 1.

[0159] Furthermore, according to this embodiment, the spacing P1 between the protrusions 64a and 64g of the protrusion row 63 closest to the vapor flow path 50 (vapor passage 51) and the protrusions 64b and 64f of the protrusion row 63 adjacent to the protrusions 64a and 64g of the protrusion row 63 is narrower than the spacing P2 between the protrusions 64b to 64f of the other protrusion rows 63. This allows for easy generation of capillary force on the actuating fluid 2b within the main flow channel 61 of the liquid flow path near the vapor flow path 50 (vapor passage 51).

[0160] Furthermore, according to this embodiment, the width w3 of the plurality of liquid flow path main channel 61 is equal to that of each other. This ensures that the capillary force generated on the actuating fluid 2b is equal in the width direction of the liquid flow path 60.

[0161] (Example of variation) Next, various variations of this embodiment will be described with reference to Figures 20 to 26. Figures 20 to 26 are diagrams showing the capillary sheet 30 of the variations. In Figures 20 to 26, the same symbols are used for the parts with the same shape as those shown in Figures 1 to 19, and detailed descriptions are omitted.

[0162] (Example 1 of the variations) In the above embodiment, an example was described in which the width w3 of the plurality of liquid flow path main channel 61 is equal to that of each liquid flow path main channel 61. However, it is not limited to this, and the width of the liquid flow path main channel 61 may also be unequal to that of each liquid flow path main channel 61.

[0163] For example, as shown in Figures 20 and 21, in the first variation, the width w3a of the main liquid flow channel 61a closest to the vapor flow path 50 (vapor passage 51) is wider than the width w3b of the other main liquid flow channels 61b. In this case, the width w3a of the two main liquid flow channels 61a closest to the vapor flow path 50 (vapor passage 51) is equal, and the width w3b of the other four main liquid flow channels 61b is equal. Preferably, the width w3a of the main liquid flow channel 61a is more than 1.1 times and less than 1.6 times the width w3b of the main liquid flow channel 61b. By having a ratio of more than 1.1 times, the capillary force in the central main liquid flow channel 61b can be increased, making it easier to transport the actuating liquid 2b toward the evaporation zone SR. By using a ratio of 1.6 times or less, the reduction in the flow rate of the actuating fluid 2b in the main flow channel 61b of the liquid flow path located inside the width direction of each liquid flow path section 60 can be suppressed.

[0164] Furthermore, as shown in Figure 20, the depth h1a of the main liquid flow channel 61a closest to the vapor flow channel 50 (vapor passage 51) can also be deeper than the depth h1b of the main liquid flow channel 61b of other liquid flow channels.

[0165] In this variation, among the plurality of protrusions 64a-64g, the widths w5a and w5g of the protrusions 64a and 64g closest to the steam passage 51 are narrower than the widths w5b and w5f of the protrusions 64b-64f in the other protrusion rows 63. Therefore, the length (distance in the Y direction) of the liquid flow path connecting groove 65 adjacent to the protrusions 64a and 64g is shortened, and the flow resistance of the liquid flow path connecting groove 65 is reduced. This suppresses the flow resistance on the outer side of the liquid flow path 60 in the width direction (Y direction), allowing the actuating vapor 2a or actuating liquid 2b to flow smoothly between the steam passage 51 and the liquid flow path 60. As a result, the condensation of the actuating vapor 2a or the evaporation of the actuating liquid 2b between the steam passage 51 and the liquid flow path 60 can proceed smoothly, thereby improving the cooling capacity of the steam chamber 1.

[0166] Thus, according to the first modification example, the width w3a of the main liquid flow channels 61a located on the outer side in the width direction of each liquid flow path portion 60 is wider than the width w3b of the other main liquid flow channels 61b. Thereby, even when the flow of the working liquid 2b from the main liquid flow channels 61a located on the outer side in the width direction of each liquid flow path portion 60 toward the main liquid flow channels 61b located on the inner side in the width direction stagnates, the condensed working liquid 2b from the vapor flow path portion 50 can be stored in the main liquid flow channels 61a with a wider width. Therefore, the working liquid 2b can smoothly condense from the vapor flow path portion 50 toward the liquid flow path portion 60. As a result, the pressure difference between the vicinity of the evaporation region SR and the condensation region CR can be maintained, and thus the reduction in the cooling capacity of the vapor chamber 1 can be suppressed.

[0167] (Second Modification Example) In the above-described embodiment, the following example has been described, that is, the widths w5a and w5g of the convex portions 64a and 64g of the convex portion rows 63 located on the outer side in the width direction of each liquid flow path portion 60 are equal to each other, and the widths w5b to w5f of the convex portions 64b to 64f of the convex portion rows 63 located on the inner side in the width direction of each liquid flow path portion 60 are equal to each other. However, it is not limited thereto, and the widths of the convex portions 64a to 64g may also change in such a manner that they gradually become wider from the convex portions 64a and 64g closest to the vapor flow path portion 50 (vapor passage 51) toward the convex portion 64d located on the inner side in the width direction.

[0168] For example, in the second modification example shown in FIGS. 22 and 23, among the plurality of convex portions 64a to 64g, the widths w5a and w5g of the convex portions 64a and 64g of the convex portion row 63 closest to the vapor flow path portion 50 (vapor passage 51) are the narrowest. Also, the width w5d of the convex portion 64d of the convex portion row 63 located on the innermost side in the width direction is the widest. The widths w5b and w5f of the convex portions 64b and 64f are wider than the widths w5a and w5g of the convex portions 64a and 64g, and the widths w5c and w5e of the convex portions 64c and 64e are wider than the widths w5b and w5f of the convex portions 64b and 64f. That is, the relationship of w5a, w5g < w5b, w5f < w5c, w5e < w5d holds.

[0169] In FIGS. 22 and 23, the widths w5a and w5g of the convex portions 64a and 64g located on the outer sides in the width direction of each liquid flow path portion 60 are equal to each other, and the widths w5b and w5f of the convex portions 64b and 64f are equal to each other. Also, the widths w5c and w5e of the convex portions 64c and 64e are equal to each other. That is, the relationship w5a = w5g < w5b = w5f < w5c = w5e < w5d holds. However, this is not limited thereto, and the widths w5a and w5g of the convex portions 64a and 64g may be different from each other. Also, the widths w5b and w5f of the convex portions 64b and 64f may be different from each other. Also, the widths w5c and w5e of the convex portions 64c and 64e may be different from each other.

[0170] The widths w5b to w5f of the respective convex portions 64b to 64f are preferably 1.1 times or more and 1.5 times or less the widths w5a to w5c and w5e to w5g of the convex portions 64a to 64c and 64e to 64g that are adjacent to each other on the outer sides in the width direction of the liquid flow path portion 60. That is, the widths w5b and w5f of the convex portions 64b and 64f are preferably 1.1 times or more and 1.5 times or less the widths w5a and w5g of the convex portions 64a and 64g. Also, the widths w5c and w5e of the convex portions 64c and 64e are preferably 1.1 times or more and 1.5 times or less the widths w5b and w5f of the convex portions 64b and 64f. Also, the width w5d of the convex portion 64d is preferably 1.1 times or more and 1.5 times or less the widths w5c and w5e of the convex portions 64c and 64e.

[0171] Specifically, the widths w5a and w5g of the convex portions 64a and 64g may be, for example, 1.5 μm or more and 430 μm or less. The widths w5b and w5f of the convex portions 64b and 64f may be, for example, 1.5 μm or more and 450 μm or less. The widths w5c and w5e of the convex portions 64c and 64e may be, for example, 1.5 μm or more and 475 μm or less. The width w5d of the convex portion 64d may be, for example, 5 μm or more and 500 μm or less.

[0172] In FIGS. 22 and 23, the widths w3 of the main liquid flow path grooves 61 are all equal to each other. However, this is not limited thereto, and the widths of the main liquid flow path grooves 61 may be unequal between the respective main liquid flow path grooves 61.

[0173] Thus, according to the second variation, the width of the protrusions 64a to 64g gradually widens from the protrusions 64a and 64g closest to the steam flow path 50 (steam passage 51) towards the protrusion 64d located at the innermost part of the protrusion row 63 in the width direction. This suppresses the flow resistance of the liquid flow path connecting groove 65 on the outer side of the width direction (Y direction) of the liquid flow path 60 compared to the flow resistance of the liquid flow path connecting groove 65 located on the inner side in the width direction. Therefore, the actuating vapor 2a or actuating liquid 2b can flow smoothly between the steam passage 51 and the liquid flow path 60. As a result, the condensation of the actuating vapor 2a or the evaporation of the actuating liquid 2b between the steam passage 51 and the liquid flow path 60 can proceed smoothly, thereby improving the cooling capacity of the steam chamber 1.

[0174] Furthermore, when the actuating fluid 2b is water, the water will freeze and expand when the temperature of the steam chamber 1 reaches below freezing. Since the pressure of water expansion is relatively high, there is a concern that the outer shell H might bulge when subjected to pressure bulging in the thickness direction of the steam chamber 1. Simultaneously, there is a concern that the protrusions 64a-64g might peel off, stretch, or tear from the island portion 33. According to this variation, the width of the plurality of protrusions 64a-64g gradually widens from the protrusions 64a and 64g closest to the steam flow path portion 50 towards the protrusion 64d located inside the width direction of the liquid flow path portion 60. This allows the pressure of water expansion within the inner liquid flow path portion 60 (e.g., around the periphery of protrusion 64d) to be released relatively easily towards the steam passage 51, thereby suppressing deformation of the protrusions 64a-64g during freezing expansion.

[0175] (Example 3) In the above embodiment, the following example is described: the widths w5a and w5g of the protrusions 64a and 64g of the protrusion row 63 located on the outer side of the width direction of each liquid flow path 60 are equal, and the widths w5b and w5f of the protrusions 64b to 64f of the protrusion row 63 located on the inner side of the width direction are equal. However, it is not limited to this; the widths of the protrusions 64a and 64g of the protrusion row 63 closest to the vapor flow path 50 (vapor passage 51) may also be equal to the widths of the protrusions 64b and 64f of the second protrusion row 63 closest to the vapor flow path 50 (vapor passage 51).

[0176] For example, in the third modification shown in FIGS. 24 and 25, among the plurality of convex portions 64a to 64g, the widths w5a and w5g of the convex portions 64a and 64g of the row 63 of the convex portions closest to the vapor flow path portion 50 (vapor passage 51) are narrower than the widths w5b and w5f of the convex portions 64b and 64f of the row 63 of the convex portions second closest to the vapor flow path portion 50 (vapor passage 51). Also, the widths w5c to w5e of the convex portions 64c to 64e located on the inner side in the width direction become wider. That is, the relationship w5a, w5b, w5f, w5g > w5c to w5e holds.

[0177] In FIGS. 24 and 25, the widths w5a, w5b, w5f, and w5g of the convex portions 64a, 64b, 64f, and 64g are equal to each other, and the widths w5c to w5e of the convex portions 64c to 64e are equal to each other. That is, the relationship w5a = w5b = w5f = w5g < w5c = w5d = w5e holds. However, it is not limited to this, and the widths w5a, w5b, w5f, and w5g of the convex portions 64a, 64b, 64f, and 64g may also be different from each other. Also, the widths w5c to w5e of the convex portions 64c to 64e may also be different from each other.

[0178] Thus, according to the third modification, two pairs (four) of the convex portions 64a, 64b, 64f, and 64g having a narrower width are provided. Thereby, in particular, the flow path resistance on the outer side in the width direction (Y direction) of the liquid flow path portion 60 can be suppressed, and thus the working vapor 2a or the working liquid 2b can flow out or flow in smoothly between the vapor passage 51 and the liquid flow path portion 60. As a result, the condensation of the working vapor 2a or the evaporation of the working liquid 2b between the vapor passage 51 and the liquid flow path portion 60 can be carried out smoothly, and thus the cooling ability of the vapor chamber 1 can be improved.

[0179] (Fourth Modification) In the above-described embodiment, an example in which the convex portions 64a to 64g are arranged in a staggered manner has been described. However, it is not limited to this, and as shown in FIG. 26, the convex portions 64a to 64g may be arranged in a lattice point pattern. Specifically, when the points at the centers of the convex portions 64a to 64g in the X direction and the Y direction are set as the center points Pc, the center points Pc of the plurality of convex portions 64a to 64g are arranged in a lattice point pattern. That is, the center points Pc of the plurality of convex portions 64a to 64g are arranged in parallel in the X direction and the Y direction. In this case, the flow path resistance of the liquid flow path connection groove 65 on the outer side in the width direction (Y direction) of the liquid flow path portion 60 can be suppressed, and thus the working vapor 2a or the working liquid 2b can flow out or flow in smoothly between the vapor passage 51 and the liquid flow path portion 60.

[0180] This invention is not limited to the above-described embodiments and variations. During implementation, variations and modifications can be made to the constituent elements without departing from its spirit. Furthermore, various inventions can be formed by appropriate combinations of the plurality of constituent elements disclosed in the above-described embodiments and variations. Several constituent elements can also be deleted from all the constituent elements shown in the embodiments and variations.

[0181] 1: Steam chamber 2a: Actuating fluid 2b: Actuating fluid 3: Sealed space 4: Injection section 10: Lower side sheet 10a: 1st lower sheet surface 10b: Second lower side sheet surface 12: Align the hole 20: Upper side sheet 20a: 1st upper sheet surface 20b: Second upper side sheet surface 22: Align the hole 30: Capillary Structure Sheets 31a: First body surface 31b: Second body surface 32: Frame section 33: Island and Taiwan Department 35: Align the hole 37:Injection flow path 39: Support Department 50: Steam Flow Path Section 51: Vapor Passage 53a: 1st wall 54a: 2nd wall 55: Protrusion 60: Liquid flow path part 61: Liquid flow path main groove 61a~61f: Liquid flow path main groove 62: Wall 63:convex row 64:convex part 64a~64g: convex part 65: Liquid flow path connection tank 66: Liquid flow path intersection CR: Condensation area D: Device E: Electronic machinery H: Outer shell Ha: Shell component h1: Depth h1a: depth h1b: depth h1c: depth L1: Length M: Metal sheet material Ma: First material surface Mb: Second material surface P1: Spacing P2: Spacing P3: Intercenter distance P4: Spacing Pc: Center point SR: Evaporation zone TD: Touch panel display t1: Thickness t2: thickness t3: thickness t4: Thickness t5: Distance w1: width w2: width w3: width w3a~w3f: width w4: width w5: width w5a~w5g: Width X: Direction Y: direction Z: Direction

Claims

1. A vapor chamber containing an actuating fluid, comprising: a first sheet; a second sheet; and a capillary sheet disposed between the first sheet and the second sheet; the capillary sheet having: a first body surface; a second body surface located opposite to the first body surface; a vapor flow path extending from the first body surface to the second body surface for through which vapor of the actuating fluid passes; and a liquid flow path disposed on the second body surface, communicating with the vapor flow path and for through which liquid of the actuating fluid passes; the liquid flow path having a plurality of main liquid flow channels arranged in parallel to each other for through which liquid of the actuating fluid passes, wherein the width of the main liquid flow channel closest to the vapor flow path is wider than the width of the other main liquid flow channels.

2. In the vapor chamber of claim 1, the width of the main liquid flow channel closest to the vapor flow channel is more than 1.1 times and less than 1.6 times the width of the main liquid flow channel of the other liquid flow channels.

3. In the vapor chamber of claim 1, the depth of the main liquid flow channel closest to the vapor flow path is greater than the depth of the other main liquid flow channels.

4. The vapor chamber of any of claims 1 to 3, wherein the center-to-center distances in the width direction of the plurality of liquid flow paths and main channels are equal.

5. The vapor chamber of any one of claims 1 to 3, wherein rows of protrusions are provided between adjacent main channels of the liquid flow path, each row of protrusions having a plurality of protrusions, and the spacing between the protrusions in the length direction of the main channel of the liquid flow path is equal between the protrusions.

6. The vapor chamber of claim 1, wherein the width of the plurality of liquid flow path main channels gradually narrows from the liquid flow path main channel closest to the vapor flow path portion toward the liquid flow path main channel located inside the width direction of the liquid flow path portion.

7. A capillary sheet for use in a vapor chamber, comprising: a first body surface; a second body surface located on the opposite side of the first body surface; a vapor flow path extending from the first body surface to the second body surface for passage of vapor of an actuating fluid; and a liquid flow path disposed on the second body surface, communicating with the vapor flow path and for passage of the liquid actuating fluid; wherein the liquid flow path has a plurality of main liquid flow channels arranged in parallel to each other for passage of the liquid actuating fluid, and wherein the width of the main liquid flow channel closest to the vapor flow path is wider than the width of the other main liquid flow channels.

8. The capillary sheet of claim 7, wherein the width of the main liquid flow channel closest to the vapor flow channel is more than 1.1 times and less than 1.6 times the width of the other main liquid flow channels.

9. The capillary sheet of claim 7, wherein the depth of the main liquid flow channel closest to the vapor flow channel is deeper than the depth of the other main liquid flow channels.

10. The capillary sheet of any one of claims 7 to 9, wherein the center-to-center distances in the width direction of the plurality of liquid flow channels are equal.

11. The capillary sheet of any one of claims 7 to 9, wherein rows of protrusions are provided between adjacent main channels of the liquid flow path, each row of protrusions having a plurality of protrusions, and the spacing between the protrusions in the length direction of the main channel of the liquid flow path is equal between the protrusions.

12. The capillary sheet of claim 7, wherein the width of the plurality of liquid flow path main channels gradually narrows from the liquid flow path main channel closest to the vapor flow path portion toward the liquid flow path main channel located inside the width direction of the liquid flow path portion.

13. An electronic machine comprising: a housing; a device housed within the housing; and a vapor chamber as claimed in any one of claims 1 to 6, which is in thermal contact with the device.

14. A vapor chamber containing an actuating fluid, comprising: a first sheet; a second sheet; and a capillary sheet disposed between the first sheet and the second sheet; the capillary sheet having: a first body surface; a second body surface located opposite to the first body surface; a vapor flow path extending from the first body surface to the second body surface for through which vapor of the actuating fluid passes; and a liquid flow path disposed on the second body surface, communicating with the vapor flow path and for through which liquid of the actuating fluid passes; the liquid flow path having a plurality of main liquid flow channels arranged in parallel to each other for through which liquid of the actuating fluid passes, and a row of protrusions being provided between adjacent main liquid flow channels, each row of protrusions having a plurality of protrusions, and the width of the protrusions in the row of protrusions closest to the vapor flow path being narrower than the width of the protrusions in the other rows of protrusions.

15. The steam chamber of claim 14, wherein the spacing between the protrusions of the protrusion row closest to the steam flow path and the protrusions of the protrusion row adjacent to the protrusion row is narrower than the spacing between the protrusions of the other protrusion rows.

16. In the vapor chamber of claim 14 or 15, the width of the liquid flow path mainstream channel closest to the vapor flow path is wider than the width of the other liquid flow path mainstream channels.

17. The vapor chamber of claim 14, wherein the width of the plurality of protrusions gradually increases from the protrusion closest to the vapor flow path toward the protrusion located inside the width direction of the liquid flow path.

18. A capillary sheet for use in a vapor chamber, comprising: a first body surface; a second body surface located on the opposite side of the first body surface; a vapor flow path extending from the first body surface to the second body surface for passage of vapor of an actuating fluid; and a liquid flow path disposed on the second body surface, communicating with the vapor flow path and for passage of the liquid actuating fluid; the liquid flow path having a plurality of main liquid flow channels arranged in parallel to each other for passage of the liquid actuating fluid, and a row of protrusions being provided between adjacent main liquid flow channels, each row of protrusions having a plurality of protrusions, wherein the width of the protrusions in the row of protrusions closest to the vapor flow path is narrower than the width of the protrusions in the other rows of protrusions.

19. The capillary sheet of claim 18, wherein the spacing between the protrusions of the protrusion row closest to the vapor flow path and the protrusions of the protrusion row adjacent to the protrusion row is narrower than the spacing between the protrusions of the other protrusion rows.

20. The capillary sheet as claimed in claim 18 or 19, wherein among the plurality of liquid flow path main channels, the width of the liquid flow path main channel closest to the vapor flow path is wider than the width of the other liquid flow path main channels.

21. The capillary sheet of claim 18, wherein the width of the plurality of protrusions gradually increases from the protrusion closest to the protrusion row of the vapor flow path toward the protrusion row of the protrusion located inside the width direction of the liquid flow path.

22. An electronic machine comprising: a housing; a device housed within the housing; and a vapor chamber as claimed in any one of claims 14 to 17, which is in thermal contact with the device.

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