Vapor chambers, wick sheets for vapor chambers, and electronic equipment

Abstract

To provide a vapor chamber capable of suppressing deformation of the wick sheet. [Solution] The wick sheet (30) for the vapor chamber (1) comprises a first main body surface (31a), a second main body surface (31b) located on the opposite side of the first main body surface (31a), a frame portion (32), and a plurality of land portions (33) spaced apart from each other within the frame portion (32). Steam passages (51) through which the vapor of the working fluid passes are formed between the plurality of land portions (33), and a liquid flow path portion (60) is formed on the second main body surface (31b) side of at least one land portion (33) that communicates with the steam passage (51) and through which the liquid working fluid passes. A bridge (41) is provided to connect the land portions (33) and the frame portion (32), or to connect the land portions (33) to each other, and the bridge (41) is thinned from at least one of the first main body surface (31a) side and the second main body surface (31b) side.

Description

Technical Field

[0001] The present disclosure relates to a vapor chamber, a wick sheet for a vapor chamber, and an electronic device.

Background Art

[0002] Central processing units (CPUs), light-emitting diodes (LEDs), power semiconductors, etc. used in mobile terminals such as mobile phones and tablet terminals are devices that generate heat. Devices that generate heat are cooled by heat dissipation members such as heat pipes. In recent years, due to the thinning of mobile terminals such as mobile phones, the thinning of heat dissipation members has also been demanded. For this reason, the development of vapor chambers that can be made thinner than heat pipes has been promoted. A working fluid is enclosed in the vapor chamber. By absorbing and diffusing the heat of the device, this working fluid cools the device. For example, Patent Document 1 discloses a sheet-type heat pipe in which two or more metal foil sheets are stacked.

[0003] More specifically, the working fluid in the vapor chamber receives heat from the device at a portion (evaporation portion) close to the device and evaporates into vapor (working vapor). The working vapor diffuses and cools in the direction away from the evaporation portion in the vapor flow path portion, and condenses into a liquid state. In the vapor chamber, a liquid flow path portion as a capillary structure (wick) is provided. The working fluid (working liquid) that has condensed into a liquid state enters from the vapor flow path portion into the liquid flow path portion, flows through the liquid flow path portion, and is transported toward the evaporation portion. Then, the working liquid receives heat again at the evaporation portion and evaporates. In this way, the working fluid refluxes in the vapor chamber while repeating phase changes, that is, evaporation and condensation, to transfer the heat of the device and improve the heat dissipation efficiency.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] This embodiment provides a vapor chamber, a wick sheet for the vapor chamber, and electronic equipment that can suppress deformation of the wick sheet.

[0006] Furthermore, this embodiment provides a vapor chamber, a wick sheet for the vapor chamber, and electronic equipment that can promote the recirculation of the working fluid within the vapor chamber. [Disclosure of the Invention]

[0007] The wick sheet according to this embodiment is a wick sheet for a vapor chamber and comprises a first main body surface, a second main body surface located on the opposite side of the first main body surface, a frame portion, and a plurality of land portions provided spaced apart from each other within the frame portion, wherein a steam passage is formed between the plurality of land portions, extending from the first main body surface to the second main body surface, through which the vapor of the working fluid passes, and a liquid flow path portion is formed on the second main body surface side of at least one of the land portions, communicating with the steam passage and through which the liquid working fluid passes, and a bridge is provided that connects the land portions and the frame portion, or connects the land portions to each other, and the bridge is thinned from at least one of the first main body surface side and the second main body surface side.

[0008] In the wick sheet according to this embodiment, the land portion may be curved or bent linear in a plan view.

[0009] In the wick sheet according to this embodiment, the plurality of land portions may include a first land portion that extends in a straight line in a plan view and a second land portion that is curved or bent in a linear shape in a plan view.

[0010] In the wick sheet according to this embodiment, the bridge has a top surface located on the second main body side, a bottom surface located on the first main body side, and a side surface located between the top surface and the bottom surface and facing in a direction opposite to the steam flow direction of the working fluid in the steam passage, and the side surface may be arranged non-parallel to the width direction of the steam passage.

[0011] In the wick sheet according to this embodiment, the bridge has a top surface located on the second main body side, a bottom surface located on the first main body side, and a side surface located between the top surface and the bottom surface and facing in a direction opposite to the steam flow direction of the working fluid in the steam passage, and the side surface may be inclined with respect to the first main body surface and the second main body surface.

[0012] In the wick sheet according to this embodiment, the fluid flow channel section has a plurality of main fluid flow channel grooves through which the liquid working fluid passes, and a plurality of fluid flow channel connecting grooves that communicate with the main fluid flow channel grooves, and the bridge may be in contact with the fluid flow channel connecting groove located on the outermost side in the width direction of the land section.

[0013] In the wick sheet according to this embodiment, the bridge has a top surface located on the second main body side, and a communication recess communicating with the liquid flow channel connecting groove may be formed on the top surface.

[0014] In the wick sheet according to this embodiment, a plurality of communication recesses may be formed on the top surface of the bridge, and a first communication channel may be formed on the top surface that connects adjacent communication recesses to each other.

[0015] In the wick sheet according to this embodiment, a second communication channel connecting the communication recess and the steam passage may be formed at the outermost position in the width direction of the bridge.

[0016] In the wick sheet according to this embodiment, the plurality of land portions include a first land portion and a second land portion, the bridge connects one end of the first land portion to an intermediate position in the second land portion, and the liquid flow channel main groove of the first land portion and the communicating recess of the bridge may extend continuously.

[0017] In the wick sheet according to this embodiment, the bridge has a top surface located on the second main body side and a bottom surface located on the first main body side, and the width of the bridge may gradually increase from the top surface toward the bottom surface.

[0018] In the wick sheet according to this embodiment, the bridge may connect the longitudinal end of the land portion to the frame portion.

[0019] The vapor chamber according to this embodiment is a vapor chamber in which a working fluid is sealed, and comprises a first sheet, a second sheet, and a wick sheet interposed between the first sheet and the second sheet, wherein the wick sheet comprises a first main body surface, a second main body surface located on the opposite side of the first main body surface, a frame portion, and a plurality of land portions provided spaced apart from each other within the frame portion, wherein a vapor passage is formed between the plurality of land portions, extending from the first main body surface to the second main body surface, through which the vapor of the working fluid passes, and a liquid flow path portion is formed on the second main body surface side of at least one of the land portions, communicating with the vapor passage and through which the liquid working fluid passes, and a bridge is provided that connects the land portions and the frame portion, or that connects the land portions to each other, wherein the bridge is thinned from at least one of the first main body surface side and the second main body surface side.

[0020] The electronic device according to this embodiment comprises a housing, a device housed within the housing, and a vapor chamber according to this embodiment that is in thermal contact with the device.

[0021] According to the embodiments of this disclosure, deformation of the wick sheet can be suppressed.

[0022] The wick sheet according to this embodiment is a wick sheet for a vapor chamber and comprises a first main body surface, a second main body surface located on the opposite side of the first main body surface, a frame portion, a plurality of land portions provided spaced apart from each other within the frame portion, and a support portion that supports the longitudinal ends of the plurality of land portions with the frame portion. Between the plurality of land portions, a steam passage is formed that penetrates the first main body surface and the second main body surface and through which the vapor of the working fluid passes. At least one of the land portions on the second main body surface side is formed, which communicates with the steam passage and through which the liquid working fluid passes. The liquid passage portion has a plurality of liquid flow channel grooves arranged parallel to each other and through which the liquid working fluid passes. Rows of protrusions are provided between adjacent liquid flow channel grooves, each row of protrusions has a plurality of protrusions, and among the plurality of protrusions, the protrusions located at the longitudinal ends of the land portions extend toward the support portion.

[0023] The wick sheet according to this embodiment is a wick sheet for a vapor chamber and comprises a first main body surface, a second main body surface located on the opposite side of the first main body surface, a frame portion, a plurality of land portions provided spaced apart from each other within the frame portion, and a support portion that supports the longitudinal ends of the plurality of land portions with the frame portion. Between the plurality of land portions, a steam passage is formed, extending from the first main body surface to the second main body surface, through which the vapor of the working fluid passes. At least one of the land portions on the second main body surface side is formed, communicating with the steam passage and through which the liquid working fluid passes. The liquid passage portion has a plurality of liquid flow channel grooves arranged parallel to each other through which the liquid working fluid passes. Rows of protrusions are provided between adjacent liquid flow channel grooves, each row of protrusions has a plurality of protrusions, and among the plurality of protrusions, the protrusions located at the longitudinal ends of the land portions are spaced apart from the support portion.

[0024] In the wick sheet according to the present embodiment, the support portion has a support portion surface located on the second main body surface side, a support portion back surface located on the first main body surface side, and a support portion inner wall surface extending from the support portion surface to the support portion back surface. The support portion inner wall surface may be such that, in a cross section, the first main body surface side is located more inward in the longitudinal direction of the vapor passage than the second main body surface side.

[0025] In the wick sheet according to the present embodiment, the support portion has a support portion surface located on the second main body surface side, a support portion back surface located on the first main body surface side, and a support portion connection surface formed to be continuous with the inner wall surface of the frame portion of the frame body portion. The support portion connection surface may be such that, in a cross section, the first main body surface side is located more inward in the longitudinal direction of the vapor passage than the second main body surface side.

[0026] In the wick sheet according to the present embodiment, the support portion has a support portion surface located on the second main body surface side, a support portion back surface located on the first main body surface side, and a support portion inner wall surface extending from the support portion surface to the support portion back surface. A intersection line can be drawn between the support portion inner wall surface and the support portion back surface. At the widthwise end of the vapor passage, the intersection line may be curved inward in the longitudinal direction of the vapor passage as it goes from the inner side to the outer side in the width direction of the vapor passage in a plan view.

[0027] In the wick sheet according to the present embodiment, the length of the convex portion located at the longitudinal end of the land portion may be longer than the lengths of the other convex portions.

[0028] In the wick sheet according to the present embodiment, the length of the convex portion located at the longitudinal end of the land portion may be shorter than the lengths of the other convex portions.

[0029] In the wick sheet according to the present embodiment, the liquid flow path portion has a plurality of convex portion rows. Among the plurality of convex portion rows, the convex portions located at the longitudinal ends of some of the convex portion rows may extend to the support portion side, and the convex portions located at the longitudinal ends of the other convex portion rows may not extend to the support portion side.

[0030] In the wick sheet according to this embodiment, the support portion has a support portion surface located on the second main body side, a support portion back surface located on the first main body side, and a support portion inner wall surface extending from the support portion surface to the support portion back surface. An intersection line can be drawn between the support portion inner wall surface and the support portion back surface. When the intersection point of the intersection line between the side surface located at one end of the land portion in the width direction is defined as the first endpoint, and the intersection point of the other intersection line between the side surface located at the other end of the land portion in the width direction is defined as the second endpoint, the convex portion located at the longitudinal end of the land portion on the first endpoint side may be located further outward in the longitudinal direction of the steam passage than the first endpoint, and the convex portion located at the longitudinal end of the land portion on the second endpoint side may be located further inward in the longitudinal direction of the steam passage than the second endpoint.

[0031] In the wick sheet according to this embodiment, the longitudinal end of the steam passage extends to the frame portion, and the support portion may be divided by the steam passage.

[0032] The vapor chamber according to this embodiment is a vapor chamber in which a working fluid is sealed, comprising a first sheet, a second sheet, and a wick sheet interposed between the first sheet and the second sheet, wherein the wick sheet has a first main surface, a second main surface located on the opposite side of the first main surface, a frame portion, a plurality of land portions provided spaced apart from each other within the frame portion, and support portions that support the longitudinal ends of the plurality of land portions with respect to the frame portion, and between the plurality of land portions are the first main surface and the A steam passage is formed through the two main body surfaces, through which the vapor of the working fluid passes. A liquid flow channel is formed on the second main body surface side of at least one of the land portions, communicating with the steam passage and through which the liquid working fluid passes. The liquid flow channel has a plurality of liquid flow channel main grooves arranged parallel to each other, through which the liquid working fluid passes. Rows of protrusions are provided between adjacent liquid flow channel main grooves, each row of protrusions having a plurality of protrusions, and of the plurality of protrusions, the protrusions located at the longitudinal end of the land portion extend toward the support portion.

[0033] The vapor chamber according to this embodiment is a vapor chamber in which a working fluid is sealed, comprising a first sheet, a second sheet, and a wick sheet interposed between the first sheet and the second sheet, wherein the wick sheet has a first main surface, a second main surface located on the opposite side of the first main surface, a frame portion, a plurality of land portions provided within the frame portion at a distance from each other, and support portions that support the longitudinal ends of the plurality of land portions with respect to the frame portion, and between the plurality of land portions, from the first main surface to the second A steam passage is formed extending from the main body surface through which the vapor of the working fluid passes, and a liquid flow channel is formed on the second main body surface side of at least one of the land portions, communicating with the steam passage and through which the liquid working fluid passes. The liquid flow channel has a plurality of liquid flow channel main grooves through which the liquid working fluid passes and which are arranged parallel to each other, and rows of protrusions are provided between adjacent liquid flow channel main grooves, each row of protrusions has a plurality of protrusions, and of the plurality of protrusions, the protrusions located at the longitudinal end of the land portion are spaced apart from the support portion.

[0034] The electronic device according to this embodiment comprises a housing, a device housed within the housing, and a vapor chamber according to this embodiment that is in thermal contact with the device.

[0035] According to the embodiments of this disclosure, the recirculation of the working fluid within the vapor chamber can be promoted. [Brief explanation of the drawing]

[0036] [Figure 1] Figure 1 is a schematic perspective view illustrating an electronic device according to the first embodiment. [Figure 2] Figure 2 is a top view showing a vapor chamber according to the first embodiment. [Figure 3] Figure 3 is a cross-sectional view taken along line III-III, showing the vapor chamber in Figure 2. [Figure 4] Figure 4 is a top view of the lower sheet shown in Figure 3. [Figure 5] Figure 5 is a bottom view of the upper sheet shown in Figure 3. [Figure 6] Figure 6 is a top view of the wick sheet shown in Figure 3. [Figure 7] Figure 7 is a bottom view of the wick sheet shown in Figure 3. [Figure 8] Figure 8 is a partially enlarged cross-sectional view of Figure 3 (a cross-sectional view along line VIII-VIII in Figure 2). [Figure 9] Figure 9 is a partially enlarged top view of the liquid flow channel shown in Figure 6. [Figure 10] Figures 10(a) and 10(b) are cross-sectional views showing modified examples of the bridge. [Figure 11] Figures 11(a)-(c) illustrate a method for manufacturing a vapor chamber according to the first embodiment. [Figure 12] Figures 12(a)-(c) show a wick sheet according to a first modification of the first embodiment. [Figure 13] Figures 13(a) and 13(b) show a wick sheet according to a second modification of the first embodiment. [Figure 14] Figures 14(a)-(c) show a wick sheet according to a third modification of the first embodiment. [Figure 15] Figures 15(a)-(f) show a wick sheet according to a third modification of the first embodiment. [Figure 16] Figures 16(a)-(c) show a wick sheet according to a fourth modification of the first embodiment. [Figure 17] Figures 17(a)-(c) show a wick sheet according to a fourth modification of the first embodiment. [Figure 18] Figures 18(a)-(c) show a wick sheet according to a fifth modification of the first embodiment. [Figure 19] Figures 19(a)-(c) show a bridge according to a sixth modification of the first embodiment. [Figure 20] Figures 20(a)-(c) show a bridge according to a seventh modification of the first embodiment. [Figure 21] Figures 21(a) and 21(b) show a bridge according to a seventh modification of the first embodiment. [Figure 22] Figures 22(a) and 22(b) show a bridge according to the eighth modified example of the first embodiment. [Figure 23] Figures 23(a) and 23(b) show a bridge according to the ninth modification of the first embodiment. [Figure 24] Figures 24(a) and 24(b) show a bridge according to a tenth modified example of the first embodiment. [Figure 25] Figures 25(a) and 25(b) show a bridge according to a tenth modified example of the first embodiment. [Figure 26] Figure 26 shows a bridge according to a tenth modification of the first embodiment. [Figure 27] Figures 27(a) and 27(b) show a bridge according to the 11th modified example of the first embodiment. [Figure 28] Figure 28 is a top view showing a vapor chamber according to the second embodiment. [Figure 29] Figure 29 is a top view of a wick sheet according to the second embodiment. [Figure 30] Figure 30 is a bottom view of the wick sheet according to the second embodiment. [Figure 31] Figure 31 is a partially enlarged cross-sectional view of a wick sheet according to the second embodiment. [Figure 32] Figure 32 is a partially enlarged top view of the liquid flow channel shown in Figure 29. [Figure 33] Figure 33 is an enlarged top view (enlarged view of part XXXIII in Figure 29) showing the frame and support parts of the wick sheet. [Figure 34] Figure 34 is an enlarged cross-sectional view (cross-sectional view along line XXXIV-XXXIV in Figure 33) showing the frame and support parts of the wick sheet. [Figure 35] Figure 35 is an enlarged top view showing the frame and support portion of a wick sheet according to the first modification of the second embodiment. [Figure 36]Figures 36(a) and 36(b) are enlarged top views showing the frame and support portion of a wick sheet according to a second modification of the second embodiment. [Figure 37] Figures 37(a)-(d) are enlarged top views showing the frame and support portion of a wick sheet according to a third modified example of the second embodiment. [Figure 38] Figure 38 is an enlarged top view showing the frame and support portion of a wick sheet according to a fourth modification of the second embodiment. [Figure 39] Figure 39 is a top view of a wick sheet according to the third embodiment. [Figure 40] Figure 40 is an enlarged top view (enlarged view of section XL in Figure 39) showing the frame and support portion of the wick sheet according to the third embodiment. [Figure 41] Figure 41 is an enlarged cross-sectional view (cross-sectional view along the line XLI-XLI in Figure 40) showing the frame and support portion of the wick sheet according to the third embodiment. [Figure 42] Figure 42 is an enlarged top view showing the frame and support portion of a wick sheet according to the first modification of the third embodiment. [Figure 43] Figure 43(a) is an enlarged top view showing the frame and support portion of a wick sheet according to a second modification of the third embodiment, and Figure 43(b) is a cross-sectional view taken along the line XLIII-XLIII in Figure 43(a). [Figure 44] Figures 44(a) and 44(b) are enlarged top views showing the frame and support portion of a wick sheet according to a third modification of the third embodiment. [Modes for carrying out the invention]

[0037] (First Embodiment) The first embodiment will be described below with reference to Figures 1 to 27. Note that, for the sake of illustration and ease of understanding, the scale and aspect ratios of the drawings attached to this specification have been appropriately altered and exaggerated from those of the actual object.

[0038] Furthermore, the terms used in this specification to specify shapes, geometric conditions, physical properties, and their degrees, such as "parallel," "orthogonal," and "identical," as well as values ​​for lengths, angles, and physical properties, are not bound by strict meanings. These terms or numerical values ​​should be interpreted to include a range within which similar functions can be expected. In addition, for clarity, the shapes of multiple parts that can be expected to perform similar functions are regularly depicted in the drawings. However, the shapes of these parts may differ from each other within the range within which the function can be expected, without being bound by strict meanings. Also, in the drawings, boundary lines indicating joint surfaces between members are shown as simple straight lines for convenience. Boundary lines are not required to be strictly straight lines. The shape of the boundary line is arbitrary within the range within which the desired joint performance can be expected.

[0039] The vapor chamber, wick sheet for the vapor chamber, and electronic equipment in this embodiment will be described with reference to Figures 1 to 10. The vapor chamber 1 in this embodiment is a device mounted on the electronic equipment E to cool the device D, which is a heat-generating element housed in the electronic equipment E. Examples of device D include electronic devices (cooling devices) that generate heat, such as those used in mobile terminals and tablet terminals. Examples of electronic devices that generate heat include central processing units (CPUs), light-emitting diodes (LEDs), and power semiconductors.

[0040] Here, we will first describe the electronic device E equipped with the vapor chamber 1 according to this embodiment, using a tablet terminal as an example. As shown in Figure 1, the electronic device E (for example, a tablet terminal) comprises a housing H, a device D housed within the housing H, and the vapor chamber 1. In the electronic device E shown in Figure 1, a touch panel display TD is provided on the front of the housing H. The vapor chamber 1 is housed within the housing H and positioned to be in thermal contact with the device D. This allows the vapor chamber 1 to receive the heat generated by the device D when the electronic device E is in use. The heat received by the vapor chamber 1 is released to the outside of the vapor chamber 1 via the working fluids 2a and 2b, which will be described later. In this way, the device D is effectively cooled. When the electronic device E is a tablet terminal, the device D corresponds to a central processing unit, etc.

[0041] Next, the vapor chamber 1 according to this embodiment will be described. As shown in Figures 2 and 3, the vapor chamber 1 has a sealed space 3 containing working fluids 2a and 2b. The vapor chamber 1 is configured to effectively cool the device D of the electronic device E described above by the repeated phase changes of the working fluids 2a and 2b in the sealed space 3. Examples of working fluids 2a and 2b include pure water, ethanol, methanol, acetone, and mixtures thereof. The working fluids 2a and 2b may also have freeze-expanding properties. That is, the working fluids 2a and 2b may be fluids that expand when frozen. Examples of working fluids 2a and 2b with freeze-expanding properties include pure water, or an aqueous solution of pure water with additives such as alcohol added.

[0042] As shown in Figures 2 and 3, the vapor chamber 1 comprises a lower sheet 10 (first sheet), an upper sheet 20 (second sheet), and a wick sheet for the vapor chamber (hereinafter simply referred to as the wick sheet 30). The wick sheet 30 is interposed between the lower sheet 10 and the upper sheet 20. In this embodiment, the vapor chamber 1 has the lower sheet 10, the wick sheet 30, and the upper sheet 20 stacked in this order.

[0043] The vapor chamber 1 is generally formed in the shape of a thin, flat plate. The planar shape of the vapor chamber 1 is arbitrary, but it may be rectangular as shown in Figure 2. The planar shape of the vapor chamber 1 may be, for example, a rectangle with one side of 50 mm to 200 mm and the other side of 150 mm to 600 mm, or a square with one side of 70 mm to 300 mm, and the planar dimensions of the vapor chamber 1 are arbitrary. In this embodiment, as an example, an example in which the planar shape of the vapor chamber 1 is rectangular with the X direction as the longitudinal direction, as will be described later, will be explained. In this case, as shown in Figures 4 to 7, the lower sheet 10, the upper sheet 20 and the wick sheet 30 may have the same planar shape as the vapor chamber 1. Note that the planar shape of the vapor chamber 1 is not limited to a rectangle, and can be any shape such as a circle, ellipse, L-shape, T-shape, U-shape, etc.

[0044] As shown in Figure 2, the vapor chamber 1 has an evaporation region SR where the working fluids 2a and 2b evaporate, and a condensation region CR where the working fluids 2a and 2b condense.

[0045] The evaporation region SR is the region that overlaps with device D in a plan view and is the region where device D is attached. The evaporation region SR can be placed anywhere 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 Figure 2). Heat from device D is transferred to the evaporation region SR, and this heat causes the liquid working fluid (referred to as working fluid 2b as appropriate) to evaporate in the evaporation region SR. Heat from device D can be transferred not only to the region that overlaps with device D in a plan view, but also to the surrounding area. Therefore, the evaporation region SR includes the region that overlaps with device D and the surrounding area in a plan view. Here, a plan view is the view from a direction perpendicular 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, described later) and the surface that releases the received heat (the first lower sheet surface 10a of the lower sheet 10, described later). In other words, a plan view corresponds to, for example, the vapor chamber 1 as seen from above or below, as shown in Figure 2.

[0046] The condensation region CR is the area that does not overlap with device D in a plan view, and is the area where the working vapor 2a primarily releases heat and condenses. The condensation region CR can also be described as the area surrounding the evaporation region SR. In the condensation region CR, heat from the working vapor 2a is released to the lower sheet 10, and the working vapor 2a is cooled and condenses in the condensation region CR.

[0047] Furthermore, when the vapor chamber 1 is installed inside a mobile terminal, the top-bottom relationship may be disrupted depending on the orientation 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. For this reason, the following explanation will be given with the lower sheet 10 positioned at the bottom and the upper sheet 20 positioned at the top.

[0048] As shown in Figure 3, the lower sheet 10 has a first lower sheet surface 10a located on the opposite side from the wick sheet 30, and a second lower sheet surface 10b located on the opposite side from the first lower sheet surface 10a (i.e., on the side of the wick sheet 30). The lower sheet 10 may be formed to be flat overall, and the lower sheet 10 may have a uniform thickness overall. A housing member Ha, which constitutes part of the housing of a mobile terminal or the like, is attached to this first lower sheet surface 10a. The entire first lower sheet surface 10a may be covered by the housing member Ha. As shown in Figure 4, alignment holes 12 may be provided at the four corners of the lower sheet 10.

[0049] As shown in Figure 3, the upper sheet 20 has a first upper sheet surface 20a located on the side of the wick sheet 30, and a second upper sheet surface 20b located on the opposite side of the first upper sheet surface 20a. The upper sheet 20 may be formed to be flat overall, and the upper sheet 20 may have a uniform thickness overall. The device D described above is attached to this second upper sheet surface 20b. As shown in Figure 5, alignment holes 22 may be provided at the four corners of the upper sheet 20.

[0050] As shown in Figure 3, the wick sheet 30 comprises a steam passage section 50 and a liquid passage section 60 arranged adjacent to the steam passage section 50. The wick sheet 30 also has a first main body surface 31a and a second main body surface 31b located on the opposite side from the first main body surface 31a. The first main body surface 31a is located on the side of the lower sheet 10, and the second main body surface 31b is located on the side of the upper sheet 20.

[0051] The second lower sheet surface 10b of the lower sheet 10 and the first main body surface 31a of the wick sheet 30 may be permanently joined to each other by diffusion bonding. Similarly, the first upper sheet surface 20a of the upper sheet 20 and the second main body surface 31b of the wick sheet 30 may be permanently joined to each other by diffusion bonding. Note that the lower sheet 10, upper sheet 20 and wick sheet 30 may be joined by other methods such as brazing, as long as they can be permanently joined, rather than by diffusion bonding. Note that the term "permanently joined" is not bound by a strict meaning. "Permanently joined" means that the bond between the lower sheet 10 and the wick sheet 30 can be maintained to the extent that the airtightness of the sealed space 3 can be maintained when the vapor chamber 1 is in operation, and the bond between the upper sheet 20 and the wick sheet 30 can be maintained.

[0052] As shown in Figures 3, 6, and 7, the wick sheet 30 according to this embodiment has a frame portion 32 formed in the shape of a rectangular frame in plan view, and a land portion 33 provided within the frame portion 32. The frame portion 32 and the land portion 33 are parts of the wick sheet 30 material that remain without being removed by etching in the etching process described later. In this embodiment, the frame portion 32 is formed in the shape of a rectangular frame in plan view, but it is not limited to this, and can be any frame shape such as a circular frame, an elliptical frame, an L-shaped frame, a T-shaped frame, or a U-shaped frame. A steam flow path portion 50 is defined inside the frame portion 32. That is, the working steam 2a flows inside the frame portion 32, around the land portion 33.

[0053] In this embodiment, the land portion 33 may extend in an elongated shape with the X direction (first direction, left-right direction in Figure 6) as its longitudinal direction when viewed from above. The planar shape of the land portion 33 is an elongated rectangle, but is not limited to this, and can be any shape such as a circular arc, an S-shape or other curved shape, a V-shape or an L-shape or other bent line shape. In addition, each land portion 33 may be spaced equally apart in the Y direction (second direction, up-down direction in Figure 6) and arranged parallel to each other. The working steam 2a is configured to flow around each land portion 33 and be transported toward the condensation region CR. This suppresses obstruction of the flow of the working steam 2a. The width w1 of the land portion 33 (see Figure 8) may be, for example, 30 μm or more and 3000 μm or less. Here, the width w1 of the land portion 33 is the dimension of the land portion 33 in the Y direction, and means the dimension at the widest position of the land portion 33 (for example, the position where the protrusion 55 described later exists).

[0054] The frame portion 32 and each land portion 33 are diffusion-bonded to the lower sheet 10 and also to the upper sheet 20. This improves the mechanical strength of the vapor chamber 1. The first wall surface 53a and the second wall surface 54a of the steam passage 51, which will be described later, constitute the side walls of the land portion 33. The first main body surface 31a and the second main body surface 31b of the wick sheet 30 may be formed flat over the frame portion 32 and each land portion 33.

[0055] The steam passage section 50 is primarily a passage through which the working fluid steam (referred to as working steam 2a as appropriate) passes. The steam passage section 50 extends from the first main body surface 31a to the second main body surface 31b and penetrates the wick sheet 30.

[0056] As shown in Figures 6 and 7, the steam flow channel section 50 in this embodiment has a plurality of steam passages 51. The steam passages 51 are formed inside the frame section 32 and outside the land section 33, that is, between the frame section 32 and the land section 33, and between adjacent land sections 33. The planar shape of each steam passage 51 is an elongated rectangle, but it is not limited to this and can be any shape, such as a circular arc, an S-shape or other curved shape, or a V-shape, L-shape or other bent line shape. The steam flow channel section 50 is divided into a plurality of steam passages 51 by a plurality of land sections 33.

[0057] As shown in Figure 3, the steam passage 51 is formed to extend from the first main surface 31a to the second main surface 31b of the wick sheet 30. The steam passage 51 is also formed to penetrate the wick sheet 30 from the first main surface 31a to the second main surface 31b.

[0058] The steam passage 51 may also be formed by etching from the first main surface 31a and the second main surface 31b of the wick sheet 30, respectively, in an etching process described later. In this case, as shown in Figure 8, the steam passage 51 has a curved first wall surface 53a and a curved second wall surface 54a. The first wall surface 53a is located on the first main surface 31a side and is curved in a shape that is concave inward in the width direction (Y direction) of the land portion 33. The second wall surface 54a is located on the second main surface 31b side and is curved in a shape that is concave inward in the width direction (Y direction) of the land portion 33. The first wall surface 53a and the second wall surface 54a meet at a projection 55 that is formed to protrude inward from the steam passage 51. The projection 55 may be formed at an acute angle in cross-section. The planar area of ​​the steam passage 51 is minimized at the location where the projection 55 exists. The width w2 of the steam passage 51 (see Figure 8) may be, for example, 100 μm or more and 5000 μm or less. Here, the width w2 of the steam passage 51 is the width at the narrowest part of the steam passage 51, and in this case, it refers to the distance measured in the width direction (Y direction) at the position where the projection 55 exists. The width w2 of the steam passage 51 also corresponds to the gap between adjacent land portions 33 in the width direction (Y direction).

[0059] The position of the projection 55 in the thickness direction (Z direction) of the wick sheet 30 is shifted towards the second body surface 31b from the midpoint between the first body surface 31a and the second body surface 31b. When the distance between the projection 55 and the second body surface 31b is t5 (see Figure 8), the distance t5 may be 5% or more, 10% or more, or 20% or more of the thickness t4 of the wick sheet 30 (see Figure 8), which will be described later. The distance t5 may also be 50% or less, 40% or less, or 30% or less of the thickness t4 of the wick sheet 30. However, the position of the projection 55 in the thickness direction (Z direction) of the wick sheet 30 may be at the midpoint between the first body surface 31a and the second body surface 31b, or at a position shifted towards the first body surface 31a from the midpoint. The position of the projection 55 is arbitrary as long as the steam passage 51 penetrates the wick sheet 30 in the thickness direction (Z direction).

[0060] Furthermore, in this embodiment, the cross-sectional shape of the steam passage 51 is defined by a projection 55 that is formed to protrude inward, but it is not limited to this. For example, the cross-sectional shape of the steam passage 51 may be trapezoidal, rectangular, or barrel-shaped.

[0061] The steam flow path section 50, including the steam passage 51 configured in this way, constitutes a part of the sealed space 3 described above. As shown in Figure 3, the steam flow path section 50 according to this embodiment is mainly defined by the lower sheet 10, the upper sheet 20, and the frame portion 32 and land portion 33 of the wick sheet 30 described above. Each steam passage 51 has a relatively large flow path cross-sectional area to allow the working steam 2a to pass through.

[0062] As shown in Figures 2, 6, 7, and 8, a plurality of bridges 41 are provided within the steam passage section 50. Of the plurality of bridges 41, some bridges 41 connect the land section 33 to the frame section 32, while other bridges 41 connect adjacent land sections 33 to each other. Specifically, each bridge 41 connects a land section 33 to a land section 33 or frame section 32 adjacent to that land section 33 in the width direction (Y direction). Each bridge 41 is provided so as to traverse the steam passage 51 in the width direction (Y direction), and in this case, one bridge 41 is provided in every steam passage 51. By providing bridges 41 in every steam passage 51 in this way, deformation of each land section 33 can be effectively suppressed.

[0063] The position of the bridge 41 in the steam flow path 50 is not critical, but it is preferable to place the bridge 41 in a relatively wider portion of the steam flow path 50. This prevents the cross-sectional area of ​​the steam flow path 50 from narrowing at the location where the bridge 41 is placed, thereby suppressing an increase in the resistance of the steam flow path 50. For example, if the width of a single steam passage 51 changes along the longitudinal direction of the steam passage 51, the bridge 41 may be provided in a relatively wider portion of the steam passage 51. In this case, it is possible to suppress a decrease in the movement speed of the working steam 2a at the bridge 41. Alternatively, if the widths of multiple steam passages 51 differ from each other, the bridge 41 may be placed in the steam passage 51 that is relatively wider among the multiple steam passages 51. In this case, it is possible to suppress the occurrence of a portion in the vapor chamber 1 where the flow of working steam 2a is partially difficult (a low-temperature portion).

[0064] Each bridge 41 has a rectangular shape in plan view. The bridge 41 is integrally formed with the land portion 33 and the frame portion 32, and is made of the same material as the land portion 33 and the frame portion 32. The bridge 41 can be placed at any position in the longitudinal direction (X direction) of the land portion 33. In this case, the bridge 41 is located at an intermediate position in the longitudinal direction of the land portion 33, between the evaporation region SR and the condensation region CR. Multiple bridges 41 are arranged in a straight line in plan view. Specifically, the line connecting the centers of each bridge 41 lies on a straight line parallel to the width direction (Y direction) of the land portion 33. This allows multiple land portions 33 to be constrained at the same location in the longitudinal direction (X direction), thereby more effectively suppressing the deformation of the land portion 33.

[0065] The bridge 41 is a region that does not penetrate the wick sheet 30 in the thickness direction, and is thinner than the frame portion 32 and the land portion 33. This allows the thickness of the bridge 41 to be thinner than the height of the steam passage 51 (thickness t4 of the wick sheet 30), preventing the steam passage 51 from being blocked. Therefore, the bridge 41 can be prevented from obstructing the flow of working steam 2a within the steam passage 51.

[0066] Furthermore, the bridge 41 is thinned by half-etching from the first body surface 31a side. Therefore, when the projection 55 is located closer to the second body surface 31b than to the first body surface 31a (see Figure 8), the thickness of the bridge 41 can be made thin in a single etching process. This prevents the bridge 41 from increasing the steam resistance of the steam passage 51 and from increasing the weight of the wick sheet 30. Also, since the bridge 41 and the liquid flow channel 60 are adjacent to each other, even if a small gap occurs between the bridge 41 and the upper sheet 20, the working fluid 2b that enters this gap can be released from the liquid flow channel 60. Therefore, when the working fluid 2b freezes in an environment with a temperature lower than the freezing point of the working fluid 2b, it is possible to prevent the gap between the bridge 41 and the upper sheet 20 from widening due to the frozen working fluid 2b.

[0067] As shown in Figure 8, the bridge 41 has a top surface 41b located on the second main surface 31b side and a bottom surface 41a located on the first main surface 31a side. The top surface 41b is a flat surface and is located on the same plane as the second main surface 31. The entire or a part of the top surface 41b may be diffusion-bonded to the upper sheet 20. The bottom surface 41a is exposed on the steam passage 51 side. The bottom surface 41a is a surface formed by etching from the first main surface 31a side and may consist of a curved surface that curves toward the second main surface 31b side. The bridge 41 may also be formed together with the steam passage 51 when it is formed by etching. In this case, the bottom surface 41a consists of a curved surface that extends continuously from the first wall surface 53a of the steam passage 51. The thickness t6 of the bridge 41 (thickness at the thinnest point) may be 5% or more, 10% or more, or 20% or more of the thickness t4 of the wick sheet 30, which will be described later. The thickness t6 of the bridge 41 may be 50% or less, 40% or less, or 30% or less of the thickness t4 of the wick sheet 30.

[0068] As shown in Figure 9, the bridge 41 has a side surface 41c between its top surface 41b and bottom surface 41a. The side surface 41c faces in a direction opposite to the flow direction of the working steam 2a in the steam passage 51. The side surface 41c may consist of a flat surface perpendicular to the longitudinal direction (X direction) of the steam passage 51.

[0069] In this way, by connecting the land portion 33 with other land portions 33 or frame portion 32 by the bridge 41, the length of the elongated space (part of the steam passage 51) that penetrates the wick sheet 30 in one direction (X direction) is reduced. This prevents the wick sheet 30 from becoming like a curtain in one direction (X direction). As a result, the wick sheet 30 becomes less prone to deformation during handling, improving the handling of the wick sheet 30 during the manufacturing of the vapor chamber 1. Furthermore, the flatness of the wick sheet 30 after completion is improved, leading to an improvement in the quality of the vapor chamber 1.

[0070] Furthermore, the bridge 41 may also be thinned by half-etching from the second body surface 31b side (Figure 10(a)). In this case, since the bridge 41 does not exist on the second body surface 31b side, the working steam 2a or working fluid 2b can be smoothly passed between the steam passage 51 and the liquid passage section 60. In addition, the working fluid 2b accumulated on the top surface 41b of the bridge 41 can be easily recovered. Alternatively, the bridge 41 may be thinned by half-etching from both the first body surface 31a side and the second body surface 31b side (Figure 10(b)). In this case, the bridge 41 is located approximately in the center of the first body surface 31a and the second body surface 31b in the thickness direction. This makes it possible to suppress the bridge 41 from being prone to breaking from only one side of the first body surface 31a or the second body surface 31b.

[0071] As shown in Figures 6 and 7, a support portion 39 is provided within the steam flow channel 50 to support the longitudinal (X-direction) end of the land portion 33 on the frame portion 32. The support portion 39 supports adjacent land portions 33 to each other. The support portion 39 is provided on one side (X-direction positive side) of the land portion 33 in the longitudinal direction (X-direction). The support portion 39 may also be provided on both sides of the land portion 33 in the longitudinal direction (X-direction). It is preferable that the support portion 39 is formed so as not to obstruct the flow of working steam 2a diffusing through the steam flow channel 50. In this case, the support portion 39 is positioned on the first main body surface 31a side of the wick sheet 30, and a space communicating with the steam flow channel 50 is formed on the second main body surface 31b side. In Figure 6, the support portion 39 is shown in gray. The support portion 39 is thinned by half-etching from the second main body surface 31b side. The support portion 39 is a region that does not penetrate the wick sheet 30 in the thickness direction and is thinner than the frame portion 32. This makes the thickness of the support portion 39 thinner than the thickness of the wick sheet 30, preventing the steam passage 51 from being divided in the X and Y directions. However, the design is not limited to this, and the support portion 39 may also be located on the second main body surface 31b side. Furthermore, spaces communicating with the steam passage portion 50 may be formed on both the surface of the support portion 39 on the first main body surface 31a side and the surface on the second main body surface 31b side.

[0072] Furthermore, as shown in Figure 2, the vapor chamber 1 may also be provided with an injection section 4 at one end edge in the X direction (the negative X direction side) for injecting the working fluid 2b into the sealed space 3. In the configuration shown in Figure 2, the injection section 4 is located on the side of the evaporation region SR. The injection section 4 has an injection channel 37 formed in the wick sheet 30. This injection channel 37 is formed on the second main body surface 31b side of the wick sheet 30 and is formed in a concave shape from the second main body surface 31b side. After the vapor chamber 1 is completed, the injection channel 37 is sealed. The injection channel 37 is also in communication with the vapor channel section 50, and the working fluid 2b is injected into the sealed space 3 by passing through the injection channel 37. Depending on the arrangement of the liquid channel section 60, the injection channel 37 may be made to communicate with the liquid channel section 60.

[0073] In this embodiment, the injection section 4 is shown to be located on one of a pair of edges of the vapor chamber 1 in the X direction, but it is not limited to this and can be located at any position.

[0074] As shown in Figures 3, 6, and 8, the liquid channel section 60 is provided on the second main body surface 31b of the wick sheet 30. The liquid channel section 60 is primarily through which the working fluid 2b passes. This liquid channel section 60 constitutes part of the sealed space 3 described above and is in communication with the vapor channel section 50. The liquid channel section 60 is configured as a capillary structure (wick) for transporting the working fluid 2b to the evaporation region SR. In this embodiment, the liquid channel section 60 is provided on the second main body surface 31b of each land section 33 of the wick sheet 30. The liquid channel section 60 may be formed over the entire second main body surface 31b of each land section 33. Also, the liquid channel section 60 may not be formed on some of the land sections 33 among the multiple land sections 33.

[0075] As shown in Figure 9, the fluid flow channel section 60 has a plurality of fluid flow channel main grooves 61 through which the working fluid 2b passes and which are arranged parallel to each other, and a plurality of fluid flow channel connecting grooves 65 that communicate with the fluid flow channel main grooves 61. In the example shown in Figure 9, each land section 33 contains six fluid flow channel main grooves 61, but this is not limited to this. The number of fluid flow channel main grooves 61 included in each land section 33 is arbitrary, and for example, it may be between 3 and 20.

[0076] As shown in Figure 9, each liquid channel main groove 61 is formed to extend along the longitudinal direction (X direction) of the land portion 33. Multiple liquid channel main grooves 61 are arranged parallel to each other. If the land portion 33 is curved in plan view, each liquid channel main groove 61 may extend in a curved shape along the curvature direction of the land portion 33. In other words, each liquid channel main groove 61 does not necessarily have to be formed in a straight line, nor does it have to extend parallel to the X direction.

[0077] The liquid flow channel main channel 61 has a smaller flow channel cross-sectional area than the steam passage 51 of the steam flow channel section 50, primarily so that the working fluid 2b flows by capillary action. The liquid flow channel main channel 61 is configured to transport the working fluid 2b condensed from the working steam 2a to the evaporation region SR. Each liquid flow channel main channel 61 is spaced apart from each other in the width direction (Y direction).

[0078] The liquid flow channel main channel groove 61 is formed by etching from the second main body surface 31b of the wick sheet 30 in an etching process described later. As shown in Figure 8, the liquid flow channel main channel groove 61 has a curved wall surface 62. This wall surface 62 defines the liquid flow channel main channel groove 61 and is curved so as to be concave from the second main body surface 31b side toward the first main body surface 31a side. In the cross-section shown in Figure 8, it is preferable that the radius of curvature of each wall surface 62 is smaller than the radius of curvature of the second wall surface 54a of the steam passage 51.

[0079] In Figure 9, the width w3 of the liquid flow channel main groove 61 may be, for example, 2 μm or more and 500 μm or less. The width w3 of the liquid flow channel main groove 61 is the length in the direction perpendicular to the longitudinal direction of the land portion 33, and in this case it is the dimension in the Y direction. The width w3 of the liquid flow channel main groove 61 also represents the dimension on the second main body surface 31b.

[0080] Furthermore, as shown in Figure 8, the depth h1 of the liquid flow channel main groove 61 may be, for example, 3 μm or more and 300 μm or less. Note that the depth h1 of the liquid flow channel main groove 61 is the distance measured from the second main body surface 31b in a direction perpendicular to the second main body surface 31b, and in this case it is the dimension in the Z direction. Also, depth h1 refers to the depth at the deepest point of the liquid flow channel main groove 61.

[0081] As shown in Figure 9, each liquid flow channel connecting groove 65 extends in a direction different from the X direction. In this embodiment, each liquid flow channel connecting groove 65 is formed to extend in the Y direction and is formed perpendicular to the liquid flow channel main groove 61. Some liquid flow channel connecting grooves 65 are arranged to connect adjacent liquid flow channel main grooves 61 to each other. Other liquid flow channel connecting grooves 65 are arranged to connect the steam flow channel section 50 (steam passage 51) with the liquid flow channel main groove 61 closest to the steam flow channel section 50. That is, the liquid flow channel connecting groove 65 extends from the end side of the land section 33 in the Y direction to the liquid flow channel main groove 61 adjacent to that end. In this way, the steam passage 51 of the steam flow channel section 50 and the liquid flow channel main groove 61 are connected.

[0082] The liquid flow channel connecting grooves 65 have a smaller flow channel cross-sectional area than the steam passages 51 of the steam flow channel section 50, primarily so that the working fluid 2b flows by capillary action. Each liquid flow channel connecting groove 65 may be arranged at equal intervals in the longitudinal direction (X direction) of the land section 33.

[0083] The liquid flow channel connecting groove 65, like the liquid flow channel main groove 61, is formed by etching and has a curved wall surface (not shown) similar to that of the liquid flow channel main groove 61. As shown in Figure 9, the width w4 (dimension in the X direction) of the liquid flow channel connecting groove 65 may be 5 μm or more and 300 μm or less. The depth of the liquid flow channel connecting groove 65 may be 3 μm or more and 300 μm or less.

[0084] As shown in Figure 9, rows of protrusions 63 are provided between adjacent main fluid channel grooves 61 in the fluid channel section 60. In the example shown in Figure 9, each land section 33 contains seven rows of protrusions 63, but this is not the only example. The number of rows of protrusions 63 included in each land section 33 is arbitrary; for example, it may be between 3 and 20 rows.

[0085] Each row of protrusions 63 is formed to extend along the longitudinal direction (X direction) of the land portion 33, as shown in Figure 9. Multiple rows of protrusions 63 are arranged parallel to each other. If the land portion 33 is curved in plan view, each row of protrusions 63 may extend in a curved shape along the curvature direction of the land portion 33. In other words, each row of protrusions 63 does not necessarily have to be formed in a straight line, nor does it have to extend parallel to the X direction. Each row of protrusions 63 is arranged with a gap between them in the width direction (Y direction).

[0086] Each row of protrusions 63 includes a plurality of protrusions 64 (liquid flow channel protrusions) arranged in the X direction. The protrusions 64 are provided within the liquid flow channel section 60 and protrude from the main liquid flow channel groove 61 and the liquid flow channel connecting groove 65, contacting the upper sheet 20. In plan view, each protrusion 64 is formed in a rectangular shape with the X direction as its longitudinal direction. Between adjacent protrusions 64 in the Y direction, a main liquid flow channel groove 61 is provided. Between adjacent protrusions 64 in the X direction, a liquid flow channel connecting groove 65 is provided. The liquid flow channel connecting groove 65 is formed to extend in the Y direction and connects adjacent main liquid flow channel grooves 61 in the Y direction. This allows the working fluid 2b to flow between these main liquid flow channel grooves 61.

[0087] The protrusions 64 are portions of the wick sheet 30 that are not removed by etching during the etching process described later, and where the material remains. In this embodiment, as shown in Figure 9, the planar shape of the protrusions 64 (the shape at the position of the second main surface 31b of the wick sheet 30) is rectangular. The width w5 of the protrusions 64 may be, for example, 5 μm or more and 500 μm or less.

[0088] In this embodiment, the protrusions 64 are arranged in a staggered (alternating) pattern. More specifically, the protrusions 64 of adjacent rows 63 in the Y direction are offset from each other in the X direction. This offset may be half the arrangement pitch of the protrusions 64 in the X direction. Note that the arrangement of the protrusions 64 is not limited to a staggered pattern and may be arranged in parallel. In this case, the protrusions 64 of adjacent rows 63 in the Y direction are aligned in the X direction as well. Note that the bridge 41 may be integrated with some of the protrusions 64 located at the ends in the width direction (Y direction).

[0089] The length L1 (dimension in the X direction) of each protrusion 64 may be uniform between each other. Also, the length L1 of each protrusion 64 is longer than the width w4 of the liquid flow channel connecting groove 65 (L1 > w4). Note that the length L1 of each protrusion 64 refers to the maximum dimension in the X direction on the second main body surface 31b.

[0090] Incidentally, the materials constituting the lower sheet 10, upper sheet 20, and wick sheet 30 are not particularly limited as long as they have good thermal conductivity, but the lower sheet 10, upper sheet 20, and wick sheet 30 may contain, for example, copper or a copper alloy. In this case, the thermal conductivity of each sheet 10, 20, and 30 can be increased, and the heat dissipation efficiency of the vapor chamber 1 can be increased. Also, when pure water is used as the working fluid 2a and 2b, corrosion can be prevented. Furthermore, if the desired heat dissipation efficiency can be obtained and corrosion can be prevented, other metal materials such as aluminum or titanium, or other metal alloy materials such as stainless steel can also be used for these sheets 10, 20, and 30.

[0091] Furthermore, the thickness t1 of the vapor chamber 1 shown in Figure 3 may be, for example, 100 μm or more and 2000 μm or less. By setting the thickness t1 to 100 μm or more, the vapor flow path 50 can be properly secured, allowing the vapor chamber 1 to function properly. On the other hand, by setting the thickness t1 to 2000 μm or less, it is possible to suppress the thickness t1 of the vapor chamber 1 from becoming too thick.

[0092] The thickness t2 of the lower sheet 10 may be, for example, 5 μm or more and 500 μm or less. By setting the thickness t2 to 5 μm or more, the mechanical strength of the lower sheet 10 can be ensured. On the other hand, by setting the thickness t2 to 500 μm or less, it is possible to suppress an increase in the thickness t1 of the vapor chamber 1. Similarly, the thickness t3 of the upper sheet 20 may be set in the same way as the thickness t2 of the lower sheet 10. The thickness t3 of the upper sheet 20 and the thickness t2 of the lower sheet 10 may be different.

[0093] The thickness t4 of the wick sheet 30 may be, for example, 50 μm or more and 1000 μm or less. By setting the thickness t4 to 50 μm or more, the vapor flow path 50 can be properly secured, allowing the vapor chamber 1 to function properly. On the other hand, by setting the thickness t4 to 1000 μm or less, it is possible to suppress an increase in the thickness t1 of the vapor chamber 1.

[0094] Next, the manufacturing method of the vapor chamber 1 according to this embodiment, which has the above configuration, will be explained using Figures 11(a)-(c). Note that Figures 11(a)-(c) show a cross-section that is substantially the same as the cross-sectional view in Figure 3.

[0095] First, we will explain the manufacturing process of the wick sheet 30.

[0096] First, as shown in Figure 11(a), a flat metal material sheet M, including a first material surface Ma and a second material surface Mb, is prepared as a preparation step.

[0097] After the preparation step, as an etching step, as shown in Figure 11(b), the metal material sheet M is etched from the first material surface Ma and the second material surface Mb to form the vapor channel section 50 and the liquid channel section 60.

[0098] 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 material sheet M by photolithography. Subsequently, the first material surface Ma and the second material surface Mb of the metal material sheet M are etched through the openings in the patterned resist film. As a result, the first material surface Ma and the second material surface Mb of the metal material sheet M are etched in a patterned manner, forming a vapor channel section 50 and a liquid channel section 60 as shown in Figure 11(b). At this time, the metal material sheet M is half-etched from the first material surface Ma side, forming a bridge 41. For the etching solution, for example, an iron 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 can be used.

[0099] The first material surface Ma and the second material surface Mb of the metal material sheet M may be etched simultaneously. However, this is not limited to this, and the etching of the first material surface Ma and the second material surface Mb may be carried out as separate processes. Furthermore, the vapor flow channel 50 and the liquid flow channel 60 may be formed by etching simultaneously or in separate processes. In the etching process, by etching the first material surface Ma and the second material surface Mb of the metal material sheet M, a predetermined outer contour shape as shown in Figures 6 and 7 is obtained. That is, the edge of the wick sheet 30 is formed.

[0100] In this way, the wick sheet 30 according to this embodiment is obtained.

[0101] Following the manufacturing process of the wick sheet 30, the lower sheet 10, the upper sheet 20, and the wick sheet 30 are joined together in a joining process, as shown in Figure 11(c). The lower sheet 10 and the upper sheet 20 may be formed from rolled material having a desired thickness.

[0102] More specifically, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are first stacked in this order. In this case, the first main surface 31a of the wick sheet 30 is superimposed on the second lower sheet surface 10b of the lower sheet 10, and the first upper sheet surface 20a of the upper sheet 20 is superimposed on the second main surface 31b of the wick sheet 30. At this time, the alignment holes 12 of the lower sheet 10 (see Figure 4), the alignment holes 35 of the wick sheet 30 (see Figures 6 and 7), and the alignment holes 22 of the upper sheet 20 (see Figure 5) are used to align each sheet 10, 20, and 30.

[0103] Next, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are tack-fastened. For example, these sheets 10, 20, and 30 may be tack-fastened by spot resistance welding, or they may be tack-fastened by laser welding.

[0104] Next, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are permanently joined by diffusion bonding. Diffusion bonding is a bonding method as follows: First, the lower sheet 10 and the wick sheet 30 to be joined are brought into close contact, and the wick sheet 30 and the upper sheet 20 are brought into close contact. Then, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are pressed and heated in the stacking direction in a controlled atmosphere such as a vacuum or in an inert gas, and the bonding is achieved by utilizing the diffusion of atoms that occurs at the bonding surface. Diffusion bonding heats the materials of each sheet 10, 20, and 30 to a temperature close to their melting point, but lower than the melting point, thus avoiding melting and deformation of each sheet 10, 20, and 30. More specifically, the first main body surface 31a of the frame portion 32 and each land portion 33 of the wick sheet 30 is diffusion-bonded to the second lower sheet surface 10b of the lower sheet 10. Furthermore, the second main body surface 31b of the frame portion 32 and each land portion 33 of the wick sheet 30 is diffusion-bonded to the first upper sheet surface 20a of the upper sheet 20. In this way, the sheets 10, 20, and 30 are diffusion-bonded, and a sealed space 3 having a steam flow path portion 50 and a liquid flow path portion 60 is formed between the lower sheet 10 and the upper sheet 20.

[0105] After the joining process, the working fluid 2b is injected from the injection section 4 into the sealed space 3.

[0106] Subsequently, the injection channel 37 described above is sealed. For example, the injection section 4 may be partially melted to seal the injection channel 37. This blocks communication between the sealed space 3 and the outside, sealing the working fluid 2b into the sealed space 3 and preventing the working fluid 2b from leaking out of the sealed space 3.

[0107] As described above, the vapor chamber 1 according to this embodiment is obtained.

[0108] Next, we will explain how the vapor chamber 1 operates, that is, how device D is cooled.

[0109] The vapor chamber 1 obtained as described above is installed inside the housing H of an electronic device E such as a mobile terminal. A device D such as a CPU, which is the device to be cooled, is attached to the second upper sheet surface 20b of the upper sheet 20 (or the vapor chamber 1 is attached to the device D). The working fluid 2b in the sealed space 3 adheres to the walls of the sealed space 3 due to 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 groove 61 of the liquid flow channel section 60, and the wall surface of the liquid flow channel connecting groove 65. The working fluid 2b may also adhere to the portion of the second lower sheet surface 10b of the lower sheet 10 that is exposed to the vapor passage 51. Furthermore, the working fluid 2b may also adhere to the portion of the first upper sheet surface 20a of the upper sheet 20 that is exposed to the vapor passage 51, the main liquid flow channel groove 61, and the liquid flow channel connecting groove 65.

[0110] When device D generates heat in this state, the working fluid 2b present 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 working fluid 2b to evaporate (vaporize) and generate working steam 2a. Much of the generated working steam 2a diffuses within the steam passages 51 that constitute the sealed space 3 (see solid arrows in Figure 6). The working steam 2a in each steam passage 51 leaves the evaporation region SR, and much of the working steam 2a is transported to the relatively lower temperature condensation region CR (the right-hand portion in Figures 6 and 7). In the condensation region CR, the working steam 2a is cooled mainly by radiating heat to the lower sheet 10. The heat received by the lower sheet 10 from the working steam 2a is transferred to the outside air via the housing member Ha (see Figure 3).

[0111] The working steam 2a condenses in the evaporation region SR by releasing heat to the lower sheet 10 in the condensation region CR, losing the latent heat absorbed in the evaporation region SR, and generating working fluid 2b. The generated working fluid 2b adheres to the first wall surfaces 53a and 2 wall surfaces 54a of each steam 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 working fluid 2b continues to evaporate in the evaporation region SR. Therefore, the working fluid 2b in the region of the liquid flow channel 60 other than the evaporation region SR (i.e., the condensation region CR) is transported toward the evaporation region SR by the capillary action of the main liquid flow channel grooves 61 (see dashed arrows in Figure 6). As a result, the working fluid 2b adhering to each steam passage 51, the second lower sheet surface 10b, and the first upper sheet surface 20a moves to the liquid flow channel 60, passes through the liquid flow channel connecting groove 65, and enters the main liquid flow channel groove 61. In this way, the working fluid 2b is filled into each main channel groove 61 and each connecting channel groove 65. As a result, the filled working fluid 2b gains a propulsive force toward the evaporation region SR due to the capillary action of each main channel groove 61 and is smoothly transported toward the evaporation region SR.

[0112] In the liquid flow channel section 60, each liquid flow channel main channel groove 61 is connected to an adjacent liquid flow channel main channel groove 61 via a corresponding liquid flow channel connecting groove 65. As a result, the working fluid 2b flows back and forth between adjacent liquid flow channel main channel grooves 61, suppressing the occurrence of dryout in the liquid flow channel main channel grooves 61. Therefore, capillary action is imparted to the working fluid 2b in each liquid flow channel main channel groove 61, and the working fluid 2b is smoothly transported toward the evaporation region SR.

[0113] The working fluid 2b, having reached the evaporation region SR, receives heat again from the device D and evaporates. The working vapor 2a evaporated from the working fluid 2b moves through the liquid flow channel connecting groove 65 in the evaporation region SR to the vapor passages 51, which have a larger flow channel cross-sectional area, and diffuses within each vapor passage 51. In this way, the working fluids 2a and 2b recirculate within the sealed space 3 while repeatedly undergoing phase changes, i.e., evaporation and condensation, transporting and releasing heat from the device D. As a result, the device D is cooled.

[0114] As described above, according to this embodiment, the wick sheet 30 has a bridge 41 connecting the land portion 33 and the frame portion 32, and another bridge 41 connecting the land portions 33 to each other. This makes it possible to shorten the length (length in the X direction) of the elongated space (part of the steam passage 51) that penetrates the wick sheet 30 in one direction (X direction). As a result, it is possible to suppress the land portions 33 of the wick sheet 30 from moving separately in a curtain-like manner, and to suppress deformation of the wick sheet 30 during handling. By suppressing deformation of the wick sheet 30, it is possible to prevent the steam passage portion 50 and the liquid passage portion 60 from being partially narrowed or blocked, and to increase the cooling capacity of the vapor chamber 1. In addition, since the bridges 41 are thinned, the steam passage 51 is not completely blocked by the bridges 41, and it is possible to suppress obstruction of the flow of working steam 2a within the steam passage 51.

[0115] (modified version) Next, referring to FIGS. 12 to 27, various modifications of the first embodiment will be described. FIGS. 12 to 27 are diagrams showing the wick sheet 30 or the bridge 41 according to the modifications. In FIGS. 12 to 27, the same parts as those shown in FIGS. 1 to 11 are denoted by the same reference numerals, and detailed descriptions thereof are omitted. Also, in FIGS. 12 to 18, for convenience, some elements such as the injection channel 37 and the support portion 39 are not shown.

[0116] (First modification) As shown in FIGS. 12(a)-(c), the bridges 41 may be evenly arranged along the longitudinal direction (X direction) of the land portion 33.

[0117] For example, as shown in FIG. 12(a), the bridge 41 may be provided at the central position in the longitudinal direction of the land portion 33. In this case, when the length along the longitudinal direction of the land portion 33 is da, each bridge 41 is located at a distance of da / 2 from the first longitudinal end portion 33a and the second longitudinal end portion 33b of the land portion 33, respectively.

[0118] Also, as shown in FIG. 12(b), a plurality (in this case, two per one vapor passage 51) of bridges 41 may be provided along the longitudinal direction of the land portion 33, and each bridge 41 may be provided at a position that equally divides the length along the longitudinal direction of the land portion 33. In this case, in each vapor passage 51, the first longitudinal end portion 33a of the land portion 33, the two bridges 41, and the second longitudinal end portion 33b of the land portion 33 are arranged at equal intervals of da / 3, respectively.

[0119] Also, as shown in FIG. 12(c), a plurality (in this case, three per one vapor passage 51) of bridges 41 may be provided along the longitudinal direction of the land portion 33, and the bridges 41 may be provided at equal intervals from each other. In this case, in each vapor passage 51, the three bridges 41 are arranged at intervals of a distance db (<da / 2) from each other.

[0120] According to this modified version, since the bridges 41 are evenly arranged along the longitudinal direction of the land portion 33, the length of the elongated space (part of the steam passage 51) that penetrates along the longitudinal direction of the land portion 33 can be reduced, and the deformation of the land portion 33 can be suppressed more effectively. In addition, since the number of bridges 41 can be reduced, it is possible to suppress the increase in steam resistance of the steam passage 51 and the increase in weight of the wick sheet 30 caused by the bridges 41.

[0121] (Second variation) As shown in Figures 13(a) and 13(b), bridges 41 adjacent to each other in the width direction (Y direction) of the land portion 33 may be offset in the longitudinal direction (X direction) of the land portion 33.

[0122] For example, as shown in Figure 13(a), the multiple land portions 33 may be arranged in a straight line in a plan view, and the line connecting the centers of the multiple bridges 41 may lie on a straight line that is not parallel to either the longitudinal direction (X direction) or the width direction (Y direction) of the land portions 33.

[0123] Furthermore, as shown in Figure 13(b), multiple bridges 41 may be arranged in a staggered (alternating) pattern in a plan view. That is, each bridge 41 and other bridges 41 adjacent to it in the width direction (Y direction) of the land portion 33 are offset from each other with respect to the longitudinal direction (X direction) of the land portion 33.

[0124] According to this modified example, even if there is slight steam resistance in the steam passage 51 near the bridge 41 and the working steam 2a stagnates at this location, heat can still be transferred to the adjacent steam passage 51 via the liquid flow path 60 adjacent to the bridge 41 (see arrows in Figures 13(a) and 13(b)). This suppresses a decrease in the heat transport performance of the steam passage 51.

[0125] (Third variation) As shown in Figures 14(a)-(c), the bridge 41 may connect the longitudinal end of the land portion 33 to the frame portion 32.

[0126] As shown in Figure 14(a), the first longitudinal end 33a of each land portion 33 and the frame portion 32 may be connected by a bridge 41.

[0127] Furthermore, as shown in Figure 14(b), the first longitudinal end 33a of each land portion 33 and the frame portion 32 may be connected by a bridge 41, and the second longitudinal end 33b of each land portion 33 and the frame portion 32 may be connected by another bridge 41.

[0128] Furthermore, as shown in Figure 14(c), each land portion 33 may be connected to the frame portion 32 by a bridge 41 at only one of its first longitudinal end 33a or second longitudinal end 33b. In this case, land portions 33 with a bridge 41 provided only at the first longitudinal end 33a and land portions 33 with a bridge 41 provided only at the second longitudinal end 33b are arranged alternately in the width direction (Y direction) of the land portion 33.

[0129] In Figures 14(a)-(c), bridges 41 are not provided at the midpoint of each land portion 33 in the longitudinal direction. Also, support portions 39 do not need to be provided within the steam passage portion 50. According to this modified example, deformation of the land portions 33 can be suppressed while preventing an increase in steam resistance in the steam passage 51 due to the bridges 41.

[0130] Figures 15(a)-(f) show examples of various shapes of bridges 41 that connect the longitudinal end of the land portion 33 to the frame portion 32. As shown in Figures 15(a)-(f), each bridge 41 has a side edge 41d located in the steam passage 51. Each side edge 41d is formed continuously with respect to the side walls (first wall surface 53a and second wall surface 54a) of the land portion 33.

[0131] As shown in Figure 15(a), the side edges 41d of each bridge 41 may extend in a substantially straight line when viewed from above.

[0132] As shown in Figure 15(b), the side edges 41d of each bridge 41 may be recessed inward in the width direction (Y direction) of each land portion 33. In this case, the side edges 41d of each bridge 41 are curved in a plan view, but are not limited to this, and may be recessed in a rectangular shape. This makes it easier for the working steam 2a to flow along the width direction (Y direction) of each land portion 33.

[0133] As shown in Figure 15(c), the width (length in the Y direction) of each bridge 41 may be narrower on the frame portion 32 side than on the land portion 33 side. In this case, the side edge 41d of each bridge 41 is straight in plan view, but is not limited to this and may be curved. This suppresses deformation of the land portion 33 and makes it easier for the operating steam 2a to flow along the width direction (Y direction) of each land portion 33.

[0134] As shown in Figure 15(d), the width (length in the Y direction) of each bridge 41 may be wider on the frame portion 32 side than on the land portion 33 side. In this case, the side edge 41d of each bridge 41 is curved in a plan view, but it is not limited to this and may be straight. This allows for more effective suppression of deformation of the land portion 33.

[0135] As shown in Figure 15(e), the connection portion 32p of the frame portion 32 to each bridge 41 may extend toward the bridge 41 side. This allows for more effective suppression of deformation of the land portion 33.

[0136] As shown in Figure 15(f), one of the pair of side edges 41d of each bridge 41 may be recessed inward in the width direction (Y direction) of each land portion 33. The other side edge 41d may extend substantially in a straight line in a plan view along the longitudinal direction (X direction) of the land portion 33. By changing the shape of the pair of side edges 41d in this way, it is possible to achieve a balance between the flow direction of the working steam 2a and the strength of the land portion 33, depending on the flow direction of the working steam 2a and the way force is applied to the land portion 33.

[0137] (Fourth variation) As shown in Figures 16(a)-(c), the land portions 33 may be in the shape of a curved line. In this case, the planar shape of the wick sheet 30 is L-shaped, and each land portion 33 extends in the shape of an L-shape when viewed from above.

[0138] As shown in Figure 16(a), each bridge 41 may be positioned at the bent portion of the land portion 33. This makes it possible to suppress deformation of the bent portion of the land portion 33, which is a part that is prone to deformation.

[0139] Furthermore, as shown in Figure 16(b), each bridge 41 may be positioned near the bent portion of the land section 33. Specifically, the distance dc between the center of a bridge 41 and the bent portion of the land section 33 closest to the bridge 41 may be 0 or greater and 30 times or less the width w2 of the steam passage 51. This suppresses deformation of the bent portion of the land section 33 and also suppresses the increase in steam resistance near the bent portion of the land section 33.

[0140] Furthermore, as shown in Figure 16(c), each bridge 41 may be positioned at a distance from the evaporation region SR. Specifically, each bridge 41 may be located closer to the condensation region CR than to the evaporation region SR when viewed along the length of the land portion 33. In this case, since each bridge 41 is provided in a region where the vapor pressure (velocity of the working steam 2a) is low, the increase in the steam resistance of the steam passage 51 due to the bridge 41 can be suppressed. Alternatively, each bridge 41 may be provided on the side where the distance from the bent portion of the land portion 33 to each end of the land portion 33 is longer. In this case, deformation of the land portion 33 can be suppressed.

[0141] In Figures 16(a)-(c), the angle at which the land portion 33 bends in a plan view is not limited to 90°, but may be any angle from acute to obtuse. Furthermore, the land portion 33 may be curved in a plan view.

[0142] For example, as shown in Figures 17(a)-(c), the land portion 33 may have a curved portion R that curves in a curved shape when viewed from above. Also, the steam passage 51 located between each land portion 33 is curved in a curved shape when viewed from above, similar to the land portion 33. By having a curved portion R in the land portion 33, the steam resistance of the working steam 2a flowing through the steam passage 51 is reduced, and heat can be transferred more easily within the plane of the vapor chamber 1.

[0143] As shown in Figure 17(a), each bridge 41 may be provided in a portion of the land portion 33 other than the curved portion R (for example, a straight portion of the land portion 33).

[0144] Furthermore, as shown in Figure 17(b), each bridge 41 may be positioned at the boundary between the curved portion R and the straight portion of the land portion 33. This makes it easier for the operating steam 2a to flow through the steam passage 51 in the curved portion R, and also suppresses deformation of the land portion 33 in the curved portion R.

[0145] Furthermore, as shown in Figure 17(c), each bridge 41 may be positioned approximately in the center of the curved portion R of the land portion 33. This makes it possible to suppress deformation of the land portion 33 in the curved portion R.

[0146] (Fifth variation) As shown in Figures 18(a)-(c), the wick sheet 30 may include a land portion 33 (first land portion 33c) that extends linearly in a plan view and a land portion 33 (second land portion 33d) that extends linearly in a curved shape in a plan view. In this case, the planar shape of the wick sheet 30 is rectangular, but it can be any shape such as circular, elliptical, L-shaped, or T-shaped.

[0147] As shown in Figure 18(a), each bridge 41 may be positioned near a bent portion of the second land portion 33d. Specifically, the distance de between the center of a bridge 41 and the bent portion of the second land portion 33d closest to the bridge 41 may be 0 or more and 30 times or less the width w2 of the steam passage 51. This suppresses deformation of the bent portion of the second land portion 33d and suppresses the increase in steam resistance near the bent portion of the second land portion 33d.

[0148] Furthermore, as shown in Figure 18(b), each bridge 41 may connect one end of the first land portion 33c to an intermediate position on one of the second land portions 33d. This suppresses deformation of the first land portion 33c.

[0149] Furthermore, as shown in Figure 18(c), each bridge 41 may connect the first land portion 33c to other land portions 33c, 33d, or frame portion 32 adjacent to the first land portion 33c in the width direction. This suppresses deformation of the first land portion 33c.

[0150] In Figures 18(a)-(c), the planar shape of the second land portion 33d can be any shape, such as a curved shape like an arc or a bent line shape like an L-shape. For example, the second land portion 33d may have a curved portion R that curves in a curved shape when viewed from above, similar to the example shown in Figures 17(a)-(c).

[0151] (Sixth variation) In Figures 19(a)-(c), the bridge 41 is thinned by half-etching from the second main body surface 31b side. In this case, the bridge 41 has a top surface 41b located on the second main body surface 31b side, a bottom surface 41a located on the first main body surface 31a side, and a side surface 41c located between the top surface 41b and the bottom surface 41a. The top surface 41b is exposed on the steam passage 51 side. Figure 19(a) is a plan view of the bridge 41, and Figures 19(b) and (c) are cross-sectional views taken along the line XIX-XIX in Figure 19(a), respectively.

[0152] As shown in Figure 19(a), the bridge 41 may have a parallelogram shape in plan view. In this case, the side surface 41c of the bridge 41 is arranged non-parallel to the width direction (Y direction) of the steam passage 51. Specifically, the angle θ (the smaller angle) between the side surface 41c of the bridge 41 and the side surface of the land section 33 may be between 20° and 70°. This suppresses steam resistance in the vicinity of the bridge 41 and allows the working steam 2a to flow smoothly in the vicinity of the bridge 41. It is not necessary for the entire area of ​​the side surface 41c of the bridge 41 to form an angle θ with respect to the side surface of the land section 33. For example, a portion of the side surface 41c of the bridge 41 may be arranged to form an angle θ between 20° and 70° with respect to the side surface of the land section 33. In this case as well, steam resistance in the vicinity of the bridge 41 is suppressed and the working steam 2a can flow smoothly in the vicinity of the bridge 41. Furthermore, the bridge 41 may have a trapezoidal shape in plan view. In this case, one of the two sides 41c of the bridge 41 may be positioned to form an angle θ of 20° or more and 70° or less with respect to the side of the land portion 33. In this case as well, steam resistance near the bridge 41 is suppressed, and the working steam 2a can flow smoothly near the bridge 41.

[0153] As shown in Figure 19(b), each side surface 41c of the bridge 41 may be perpendicular to the first main body surface 31a and the second main body surface 31b.

[0154] Furthermore, as shown in Figure 19(c), each side surface 41c of the bridge 41 may be inclined with respect to the first main body surface 31a and the second main body surface 31b. In this case, steam resistance near the bridge 41 is suppressed, and the working steam 2a can flow smoothly near the bridge 41. Such inclined side surfaces 41c can be easily manufactured simultaneously with the liquid flow channel section 60 during the etching process. Also, even if the working steam 2a collides with the bridge 41 and liquefies, the angle between the lower sheet 10 and the side surface 41c becomes obtuse, making it easier to discharge the working fluid 2b along the bridge 41.

[0155] In addition, in Figures 19(a)-(c), the bridge 41 may be thinned by half-etching from the first main body surface 31a side.

[0156] (Seventh variation) In Figures 20(a)-(c), the bridge 41 is thinned by half-etching from the second main body surface 31b side. In this case, the bridge 41 has a top surface 41b located on the second main body surface 31b side, a bottom surface 41a located on the first main body surface 31a side, and a side surface 41c located between the top surface 41b and the bottom surface 41a. The top surface 41b is exposed on the steam passage 51 side. Figure 20(a) is a plan view of the bridge 41, and Figures 20(b) and (c) are cross-sectional views taken along the line XX-XX in Figure 20(a), respectively.

[0157] As shown in Figure 20(a), each side 41c of the bridge 41 is arranged to be perpendicular to the width direction (Y direction) of the steam passage 51.

[0158] Furthermore, as shown in Figures 20(b) and 20(c), each side surface 41c of the bridge 41 may be inclined in a curved manner with respect to the first main body surface 31a and the second main body surface 31b. In this case, the length L2 of the bridge 41 in the longitudinal direction (X direction) of the steam passage 51 may be 0.5 times or more and 10 times or less the width w2 of the steam passage 51. By setting the length L2 of the bridge 41 to 0.5 times or more the width w2 of the steam passage 51, the accumulation of working steam 2a near each side surface 41c of the bridge 41 is suppressed, and the working steam 2a can flow smoothly near the bridge 41. By setting the length L2 of the bridge 41 to 10 times or less the width w2 of the steam passage 51, the portion where the steam passage 51 narrows is shortened, and the pressure loss of the working steam 2a within the steam passage 51 can be reduced.

[0159] In addition, in Figures 20(a)-(c), the bridge 41 may be thinned by half-etching from the first main body surface 31a side.

[0160] Furthermore, as shown in Figures 21(a) and (b), a portion of each side surface 41c of the bridge 41 may be convex (Figure 21(a)) or concave (Figure 21(b)) in a plan view. In this case, it is possible to facilitate the flow of the working steam 2a in the vicinity of the bridge 41. In Figures 21(a) and (b), the side surface 41c on the inlet side (negative side in the X direction) of the working steam 2a is convex or concave, but this is not limited to this, and the side surface 41c on the outlet side (positive side in the X direction) of the working steam 2a may also be convex or concave. Also, both the inlet side (negative side in the X direction) and the outlet side (positive side in the X direction) of the working steam 2a may be convex or concave.

[0161] (Variation 8) In Figures 22(a) and 22(b), the bridge 41 is thinned by half-etching from the first main body surface 31a side. In this case, the bridge 41 is in contact with at least one liquid flow channel connecting groove 65 located on the outermost side in the width direction (Y direction) of the land portion 33.

[0162] According to this modified example, even if the bridge 41 and the upper sheet 20 are not completely joined by diffusion bonding, and a small gap is created between the bridge 41 and the upper sheet 20, the working fluid 2b that enters this gap can be released through the fluid flow channel connecting groove 65. As a result, even if the working fluid 2b freezes in an environment with a temperature lower than the freezing point of the working fluid 2b, it is possible to suppress the widening of the gap between the bridge 41 and the upper sheet 20 due to the frozen working fluid 2b.

[0163] (9th variation) In Figures 23(a) and 23(b), the bridge 41 is thinned by half-etching from the first main body surface 31a side. In this case, the bridge 41 is in contact with at least one liquid flow channel connecting groove 65 located on the outermost side in the width direction (Y direction) of the land portion 33. Furthermore, a communication recess 46 communicating with the liquid flow channel connecting groove 65 is formed on the top surface 41b of the bridge 41. The communication recess 46 extends over the entire width direction (Y direction) of the steam passage 51.

[0164] According to this modified configuration, the working fluid 2b that enters the space between the bridge 41 and the upper sheet 20 can be released into the fluid flow channel connecting groove 65 via the connecting recess 46. This prevents the gap between the bridge 41 and the upper sheet 20 from widening due to the frozen working fluid 2b, even if the working fluid 2b freezes in an environment with a temperature lower than its freezing point.

[0165] (10th variation) In Figures 24 to 26, the bridge 41 (dotted line) is thinned by half-etching from the first main body surface 31a side. In this case, the bridge 41 is in contact with at least one liquid flow channel connecting groove 65 located on the outermost part in the width direction of the land portion 33. Furthermore, a plurality of communication recesses 46 communicating with the liquid flow channel connecting grooves 65 are formed on the top surface 41b of the bridge 41. Each of the plurality of communication recesses 46 extends across the entire width direction of the steam passage 51. The plurality of communication recesses 46 are also arranged parallel to each other.

[0166] Bridge protrusions 45 are arranged around the communication recess 46. The bridge protrusions 45 are provided on the top surface 41b of the bridge 41. The bridge protrusions 45 protrude from the communication recess 46 and abut against the upper sheet 20. Each bridge protrusion 45 is formed in a rectangular shape in a plan view, such that the width direction of the steam passage 51 is the longitudinal direction. Between adjacent bridge protrusions 45 in the longitudinal direction of the steam passage 51, each is located a communication recess 46.

[0167] According to this modified design, the working fluid 2b that enters the space between the bridge 41 and the upper sheet 20 can be released into the fluid flow channel connecting groove 65 via a plurality of communicating recesses 46. This prevents the frozen working fluid 2b from widening the gap between the bridge 41 and the upper sheet 20, even if the working fluid 2b freezes in an environment with a temperature lower than its freezing point.

[0168] As shown in Figure 24(a), the bridge protrusions 45 may extend parallel to each other over the entire width (Y direction) of the steam passage 51. Both ends of each bridge protrusion 45 are connected to the outermost protrusions 64 in the width (Y direction) of the land portion 33.

[0169] As shown in Figure 24(b), a first communication channel 47 may be formed on the top surface 41b of the bridge 41, connecting adjacent communication recesses 46. The first communication channel 47 is positioned between adjacent bridge protrusions 45 in the width direction (Y direction) of the steam passage 51. The outermost bridge protrusions 45 in the width direction (X direction) of the bridge 41 extend over the entire width direction (Y direction) of the steam passage 51. Each first communication channel 47 extends in a direction intersecting the width direction (Y direction) of the steam passage 51. In Figure 24(b), each first communication channel 47 extends in the X direction and is formed perpendicular to the longitudinal direction of the communication recess 46. This allows the working fluid 2b that enters between the bridge 41 and the upper seat 20 to escape to the liquid flow channel connecting groove 65 via the first communication channel 47 and the communication recess 46.

[0170] As shown in Figure 25(a), a second communication channel 48 connecting the communication recess 46 and the steam passage 51 may be formed at the outermost position in the width direction (X direction) of the bridge 41. The second communication channel 48 is positioned between the bridge protrusions 45 located at the outermost positions in the width direction (X direction) of the bridge 41. In Figure 25(a), the second communication channel 48 extends in the X direction and is formed perpendicular to the longitudinal direction of the communication recess 46. This allows the working fluid 2b that has entered between the bridge 41 and the upper sheet 20 to escape from the communication recess 46 to the steam passage 51. In addition, the working fluid 2b that has condensed in the steam passage 51 can enter from the second communication channel 48 and be transported to the evaporation region SR via the liquid channel section 60.

[0171] As shown in Figure 25(b), when the bridge 41 connects one end of the first land portion 33c to an intermediate position in the second land portion 33d (for example, as shown in Figure 18(b) above), a plurality of communication recesses 46 may be formed on the top surface 41b of the bridge 41. In this case, the communication recesses 46 communicate with the liquid flow channel connecting groove 65 of the second land portion 33d. Furthermore, the liquid flow channel main groove 61 of the first land portion 33c and the communication recesses 46 of the bridge 41 extend continuously. Specifically, the liquid flow channel main groove 61 of the first land portion 33c and the communication recesses 46 of the bridge 41 are arranged in a straight line in plan view. This allows the working fluid 2b that has entered between the bridge 41 and the upper seat 20 to be smoothly discharged from the communication recesses 46 towards the liquid flow channel main groove 61 of the first land portion 33c. Furthermore, the working fluid 2b condensed in the steam passage 51 can be smoothly transported from the communication recess 46 of the bridge 41 towards the main fluid channel groove 61 of the first land section 33c.

[0172] As shown in Figure 26, when the bridge 41 connects one end of the first land portion 33c to an intermediate position in the second land portion 33d, the first land portion 33c and the bridge 41 may each have a curved shape in plan view. In this case, multiple communication recesses 46 are formed on the top surface 41b of the bridge 41. Furthermore, the liquid flow channel main groove 61 of the first land portion 33c and the communication recesses 46 of the bridge 41 extend continuously. Specifically, the liquid flow channel main groove 61 of the first land portion 33c and the communication recesses 46 of the bridge 41 are connected by a continuous curve in plan view. Here, being connected by a continuous curve means that at the connection point between the bridge 41 and the first land portion 33c, the radius of curvature of the center line of the liquid flow channel main groove 61 and the radius of curvature of the center line of the communication recesses 46 coincide. This allows the working fluid 2b that has entered between the bridge 41 and the upper sheet 20 to be smoothly released from the communicating recess 46 towards the main fluid channel groove 61 of the first land section 33c. In addition, the working fluid 2b that has condensed in the steam passage 51 can be smoothly transported from the communicating recess 46 of the bridge 41 towards the main fluid channel groove 61 of the first land section 33c.

[0173] (11th variation) Figures 27(a) and 27(b) show the bridge 41 according to the 11th modification, respectively, and are cross-sectional views along the width direction (X direction) of the bridge 41. In Figures 27(a) and 27(b), the bridge 41 is thinned by half-etching from the first main body surface 31a side. In this case, the width of the bridge 41 gradually widens from the top surface 41b toward the bottom surface 41a. The side surface 41c of the bridge 41 is curved and inclined outward in the width direction (X direction) of the bridge 41 from the top surface 41b toward the bottom surface 41a. The side surface 41c of the bridge 41 is in communication with the liquid flow channel 60 of the land portion 33 connected to the bridge 41.

[0174] According to this modified example, when the working steam 2a collides with the side surface 41c of the bridge 41 and liquefies, the working fluid 2b easily flows along the curved side surface 41c into the liquid flow path 60 of the land section 33.

[0175] As shown in Figure 27(a), the top surface 41b of the bridge 41 is flat, and it is not necessary for a communication recess 46 to be formed on the top surface 41b of the bridge 41.

[0176] As shown in Figure 27(b), the top surface 41b of the bridge 41 may have a plurality of communication recesses 46 (see the 10th modified example). In this case, when the working vapor 2a collides with the side surface 41c of the bridge 41 and liquefies, the working fluid 2b can easily flow into the communication recesses 46 of the bridge 41 by traveling along the curved side surface 41c.

[0177] (Second Embodiment) Next, a second embodiment will be described with reference to Figures 28 to 38. Figures 28 to 38 are diagrams showing the second embodiment. In Figures 28 to 38, the same reference numerals are used for parts that are the same as those shown in Figures 1 to 27, and detailed descriptions are omitted.

[0178] As shown in Figure 28, the vapor chamber 1 according to this embodiment comprises a lower sheet 10 (first sheet), an upper sheet 20 (second sheet), and a wick sheet for the vapor chamber (hereinafter simply referred to as wick sheet 30). The wick sheet 30 is interposed between the lower sheet 10 and the upper sheet 20.

[0179] As shown in Figures 29 to 32, the wick sheet 30 according to this embodiment comprises a first main body surface 31a, a second main body surface 31b, a frame portion 32, a plurality of land portions 33, and a support portion 39. Steam passages 51 through which working steam 2a passes are formed between the plurality of land portions 33. A liquid flow path portion 60 is formed on the second main body surface 31b side of at least one land portion 33, communicating with the steam passage 51 and through which working fluid 2b passes. The liquid flow path portion 60 has a plurality of liquid flow main grooves 61 through which working fluid 2b passes and which are arranged parallel to each other. Rows of protrusions 63 are provided between adjacent liquid flow main grooves 61. Each row of protrusions 63 has a plurality of protrusions 64. The protrusions 64 located at the longitudinal end of the land portion 33 extend toward the support portion 39.

[0180] As shown in Figure 32, the liquid flow channel section 60 has a plurality of liquid flow channel connecting grooves 65 that communicate with the main liquid flow channel groove 61. The main liquid flow channel groove 61 has a curved wall surface 62, as shown in Figure 31. The protrusion 64 is provided within the liquid flow channel section 60 and protrudes from the main liquid flow channel groove 61 and the liquid flow channel connecting grooves 65, contacting the upper sheet 20.

[0181] Figure 33 is an enlarged top view (enlarged view of part XXXIII in Figure 29) showing the frame portion 32 and support portion 39 located on the condensation region CR side, and Figure 34 is an enlarged cross-sectional view (cross-sectional view along line XXXIV-XXXIV in Figure 33) showing the frame portion 32 and support portion 39. Here, in order to clarify the drawing, Figure 33 shows an enlarged view of the liquid flow channel main groove 61 and the row of protrusions 63, and for convenience, the number of these liquid flow channel main grooves 61 and row of protrusions 63 etc. differs from that in Figures 31 and 32.

[0182] As shown in Figure 33, the support portion 39 is located on the condensation region CR side and is provided at the longitudinal end (positive X direction) of the land portion 33. As described above, this support portion 39 connects the land portion 33 to the frame portion 32. The frame portion 32 also has an inner wall surface 32a located on the side of the support portion 39.

[0183] As shown in Figure 34, the support portion 39 has a support portion surface 39a, a support portion inner wall surface 39b, a support portion connecting surface 39c, and a support portion back surface 39d. Of these, the support portion surface 39a is the surface located on the second main body surface 31b side and is a flat surface parallel to the second main body surface 31b. The support portion inner wall surface 39b is the surface facing the steam passage 51 side (negative X direction) of the steam flow channel portion 50 and extends from the support portion surface 39a to the support portion back surface 39d. The support portion inner wall surface 39b is a curved surface, and in its cross-section, it is curved such that the side on the first main body surface 31a side is located further inward in the longitudinal direction of the steam passage 51 (negative X direction) than the side on the second main body surface 31b side. The support portion inner wall surface 39b is formed to be continuous with the first wall surface 53a and the second wall surface 54a of the steam passage 51 (see Figure 33). The support section connecting surface 39c is formed to be continuous with the inner wall surface 32a of the frame section 32. The support section connecting surface 39c is a curved surface, and in its cross-section, the side facing the first main body surface 31a is curved so that it is located further inward in the longitudinal direction (negative X direction) of the steam passage 51 than the side facing the second main body surface 31b. The back surface 39d of the support section is a surface facing the first main body surface 31a and is a flat surface located on the same plane as the first main body surface 31a. Furthermore, an intersection line 39e can be drawn between the inner wall surface 39b of the support section and the back surface 39d of the support section. Note that the inner wall surface 39b of the support section and the support section connecting surface 39c do not necessarily have to be curved surfaces; they may also be flat surfaces. It is preferable that the inner wall surface 39b of the support section and the support section connecting surface 39c are inclined surfaces. Also, it is preferable that the angle between the back surface 39d of the support section and the inner wall surface 39b of the support section in the intersection line 39e is acute.

[0184] As shown in Figure 33, of the multiple protrusions 64 formed on the land portion 33, the protrusions 64 located at the longitudinal (X-direction) end of the land portion 33 extend toward the support portion 39. That is, the protrusions 64 located at the longitudinal end of the land portion 33 are positioned on the support portion 39. As described above, each land portion 33 has multiple (four rows in Figure 33) rows of protrusions 63 formed on it. In this case, all of the rows of protrusions 63 formed on the land portion 33 extend toward the support portion 39 by the same length L3. This extending length L3 may be 10% to 80% of the width w6 of the support portion 39. The width w6 of the support portion 39 may be 50 μm to 2000 μm.

[0185] As shown in Figure 34, on the support portion 39, the protrusion 64 projects from the support portion surface 39a toward the second main body surface 31b. In this case, the bottom surface of the liquid flow channel main groove 61 formed in the land portion 33 is located on the same plane as the support portion surface 39a. However, the bottom surface of the liquid flow channel main groove 61 may be offset from the support portion surface 39a in the thickness direction (Z direction) of the land portion 33.

[0186] In this specification, "the protrusion 64 extends toward the support portion 39" means that the protrusion 64 located at the outermost longitudinal end of the land portion 33 is located further outward in the longitudinal direction of the land portion 33 than the portion of the support portion 39 adjacent to the land portion 33 that is located furthest inward in the longitudinal direction of the steam passage 51. "Support portion 39 adjacent to the land portion 33" refers to the region of the support portion 39 located between the land portion 33 and the land portion 33 adjacent to the land portion 33. In Figure 33, the protrusion 64 located furthest toward the frame portion 32 (positive X direction) of the land portion 33 is located further toward the frame portion 32 (positive X direction) than the intersection line 39e, which is the innermost portion of the adjacent support portion 39. Furthermore, the length L3 mentioned above refers to the distance between the protrusion 64 located at the outermost end of the land portion 33 in the longitudinal direction and the part of the support portion 39 that is located furthest inward in the longitudinal direction of the steam passage 51 (intersection line 39e), measured in the longitudinal direction of the land portion 33.

[0187] In this embodiment, the protrusion 64 located at the longitudinal end (X-direction positive end) of the land portion 33 on the condensation region CR side (X-direction positive side) extends toward the support portion 39. As a result, the working fluid 2b that has condensed on the support portion 39 is returned to the liquid flow path portion 60 and recovered by the capillary force of the liquid flow path portion 60 (see reference numeral 2b in Figure 33). This makes it possible to smooth the flow of the working fluid 2b when the vapor chamber 1 is in use and improves the uniformity of the vapor chamber 1. Furthermore, when the vapor chamber 1 is placed in an environment below the freezing point of the working fluid 2b, the working fluid 2b remaining on the support portion 39 will freeze, preventing damage to the vapor chamber 1. However, this is not limited to this configuration; the protrusion 64 located at the longitudinal end of the land portion 33 on the evaporation region SR side (X-direction negative side) may also extend toward the support portion 39.

[0188] The vapor chamber 1 and wick sheet 30 according to this embodiment can be manufactured in substantially the same manner as in the first embodiment, except that a bridge 41 is not formed (see Figure 11).

[0189] Next, we will describe the operation of this embodiment, which has the above configuration.

[0190] While using the vapor chamber 1 according to this embodiment, some of the working fluids 2a and 2b reach the support portion 39. It is conceivable that the working fluids 2a and 2b that reach the support portion 39 condense and accumulate on the support portion 39 as working fluid 2b. In contrast, according to this embodiment, of the multiple protrusions 64 formed on the land portion 33, the protrusions 64 located at the longitudinal end of the land portion 33 extend toward the support portion 39. As a result, the working fluid 2b accumulated on the support portion 39 is collected into the main flow channels 61 via the protrusions 64 located at the longitudinal end of the land portion 33. Therefore, the recirculation of the working fluids 2a and 2b within the sealed space 3 is promoted, the flow of the working fluids 2a and 2b is not obstructed, and the uniformity of the vapor chamber 1 can be improved.

[0191] Furthermore, it is conceivable that the electronic device E equipped with the vapor chamber 1 may be placed in a temperature environment lower than the freezing point of the working fluid 2b during use. In contrast, according to this embodiment, the accumulation of working fluid 2b on the support portion 39 is suppressed. Therefore, even if the working fluid 2b freezes, deformation of the upper sheet 20 due to the force caused by the expansion of the working fluid 2b remaining on the support portion 39 is suppressed. As a result, a decrease in the flatness of the second upper sheet surface 20b of the upper sheet 20 to which the device D is attached can be suppressed, and the formation of a gap between the second upper sheet surface 20b and the device D can be suppressed. As a result, the inhibition of heat conduction from the device D can be suppressed, and the performance degradation of the vapor chamber 1 can be suppressed.

[0192] Furthermore, according to this embodiment, the inner wall surface 39b of the support portion 39 is inclined such that, in its cross-section, the side facing the first main body surface 31a is located more towards the inside of the steam passage 51 in the longitudinal direction (negative side in the X direction) than the side facing the second main body surface 31b. This allows the working fluids 2a and 2b to flow smoothly from the support portion 39 into the steam passage 51, thereby promoting the recirculation of the working fluids 2a and 2b within the vapor chamber 1.

[0193] Furthermore, according to this embodiment, the support portion connecting surface 39c of the support portion 39 is inclined such that, in its cross-section, the first body surface 31a side is located more inward in the longitudinal direction (negative X direction) of the steam passage 51 than the second body surface 31b side. As a result, the working fluid 2b is less likely to accumulate at the corner between the frame portion 32 and the support portion 39, and the working fluid 2b can be smoothly recovered toward the fluid flow path portion 60.

[0194] (modified version) Next, various modifications of this embodiment will be described with reference to Figures 35 to 38. Figures 35 to 38 are enlarged top views showing parts of the wick sheet 30 according to each modification. In Figures 35 to 38, the same reference numerals are used for parts that are the same as those shown in Figures 28 to 34, and detailed descriptions are omitted.

[0195] (First variation) As shown in Figure 35, at the longitudinal end of the steam passage 51 (the end on the negative side in the X direction), the intersection line 39e of the support parts 39 located at both ends in the width direction (Y direction) of the steam passage 51 may be curved in plan view. That is, at each end in the width direction of the steam passage 51, the intersection line 39e of the support parts 39 curves toward the longitudinal side (negative side in the X direction) of the steam passage 51 in plan view as it moves from the inside to the outside in the width direction (Y direction) of the steam passage 51. The intersection line 39e of the support parts 39 may be arc-shaped or elliptical arc-shaped in plan view, or it may be a shape in plan view where a line segment has curves connected to both sides of it.

[0196] According to this modified example, the working fluid 2b present on the support surface 39a and the inner wall surface 39b of the support portion 39 can also be allowed to flow into the fluid flow channel 60 from the side surface (first wall surface 53a and second wall surface 54a) of the land portion 33 (see reference numeral 2b in Figure 35). As a result, the working fluid 2b accumulated on the support portion 39 is efficiently collected into the fluid flow channel 60 via the side surface of the land portion 33. Therefore, the action of the working fluids 2a and 2b circulating within the sealed space 3 can be further promoted.

[0197] (Second variation) As shown in Figures 36(a) and 36(b), the length L4 (dimension in the X direction) of the protrusion 64 located at the longitudinal (X direction) end of the land portion 33 may differ from the length L1 (dimension in the X direction) of the other protrusions 64.

[0198] For example, as shown in Figure 36(a), the length L4 of the protrusion 64A (64) located at the longitudinal end of the land portion 33 may be longer than the length L1 of the other protrusions 64 (L4 > L1). As a result, capillary force acts on the longer protrusion 64A, which suppresses the adhesion of the working fluid 2b around the protrusion 64A and allows the working fluid 2b to be efficiently returned to the fluid flow channel 60. Therefore, in a thermal cycle test in which heating and cooling are repeated, expansion of the vapor chamber 1 in the region of the support portion 39 can be suppressed.

[0199] In FIG. 36(a), the length L4 of the convex portion 64A located at the longitudinal end of a part of the convex portion rows 63 is longer than the length L1 of the other convex portions 64. On the other hand, the length of the convex portions 64 located at the longitudinal ends of some other convex portion rows 63 is the same as the length L1 of the other convex portions 64. However, this is not limited thereto, and the length L4 of the convex portions 64A located at the longitudinal ends of all the convex portion rows 63 may be longer than the length L1 of the other convex portions 64.

[0200] Also, as shown in FIG. 36(b), the lengths L5 and L6 of the convex portions 64B(64) and 64C(64) located at the longitudinal ends of the land portion 33 may be shorter than the length L1 of the other convex portions 64 (L5 < L1, L6 < L1). Thereby, since the fluid flow path connection groove 65 is arranged in the vicinity of the support portion 39, the working fluid 2b remaining on the support portion 39 can be efficiently taken into the fluid flow path portion 60. Note that the length L6 of the convex portion 64C adjacent to the convex portions 64B and 64C located at the longitudinal ends of the land portion 33 in the longitudinal direction (X direction) may also be shorter than the length L1 of the other convex portions 64.

[0201] In FIG. 36(b), the lengths L5 and L6 of the convex portions 64B and 64C located at the longitudinal ends of all the convex portion rows 63 are shorter than the length L1 of the other convex portions 64. However, this is not limited thereto, and the length L1 of the convex portions 64 located at the longitudinal ends of some of the convex portion rows 63 may be the same as the length L1 of the other convex portions 64.

[0202] (Third Modified Example) As shown in FIGS. 37(a)-(d), among the plurality (in this case, four rows) of convex portion rows 63, the convex portions 64E(64) located at the longitudinal ends of some of the convex portion rows 63 may extend toward the support portion 39 side. The convex portions 64F(64) located at the longitudinal ends of the other convex portion rows 63 do not have to extend toward the support portion 39 side.

[0203] For example, as shown in Figure 37(a), rows of protrusions 63 including protrusions 64E extending toward the support portion 39 and rows of protrusions 63 including protrusions 64F not extending toward the support portion 39 may be alternately provided in the width direction (Y direction) of the land portion 33. Note that "protrusions 64F not extending toward the support portion 39" means that the protrusions 64F overlap with the portion of the adjacent support portion 39 that is located furthest inward in the longitudinal direction of the steam passage 51, or that the land portion 33 is located further inward in the longitudinal direction than that portion.

[0204] Furthermore, as shown in Figure 37(b), the protrusions 64E of the row of protrusions 63 located on the inside of the land portion 33 in the width direction (Y direction) may extend toward the support portion 39. The protrusions 64F of the row of protrusions 63 located at both ends of the land portion 33 in the width direction do not have to extend toward the support portion 39.

[0205] Furthermore, as shown in Figure 37(c), the protrusions 64E of the rows of protrusions 63 located at both ends of the land portion 33 in the width direction (Y direction) may extend toward the support portion 39. The protrusions 64F of the rows of protrusions 63 located on the inside of the land portion 33 in the width direction do not need to extend toward the support portion 39.

[0206] Furthermore, as shown in Figure 37(d), the protrusions 64E of the row of protrusions 63 located at one end of the land portion 33 in the width direction (Y direction) may extend toward the support portion 39. The protrusions 64F of the row of protrusions 63 located at the other end of the land portion 33 in the width direction and the protrusions 64F of the row of protrusions 63 located on the inside of the land portion 33 in the width direction do not have to extend toward the support portion 39.

[0207] According to this modified configuration, the width of the inlet through which the working fluid 2b flows into the main channel groove 61 can be widened (see, for example, the double arrow in Figure 37(a)). This allows the working fluid 2b remaining on the support portion 39 to be efficiently taken into the fluid channel portion 60.

[0208] (Fourth variation) As shown in Figure 38, the intersection line 39e of the support portion 39 may be curved or bent in plan view. In this case, the intersection point between the side surface (first wall surface 53a and second wall surface 54a) located at one end of the land portion 33 in the width direction (Y direction) and the intersection line 39e is defined as the first endpoint 39g. The intersection point between the side surface located at the other end of the land portion 33 in the width direction (Y direction) and the other intersection line 39e is defined as the second endpoint 39h. In this case, the straight line connecting the first endpoint 39g and the second endpoint 39h is non-parallel to the width direction (Y direction) of the land portion 33 in plan view.

[0209] Furthermore, in Figure 38, the protrusions 64 of the row of protrusions 63 located at one end of the land portion 33 in the width direction (the end on the side of the first endpoint 39g) extend toward the support portion 39. That is, at the end on the side of the first endpoint 39g, the protrusions 64 located at the longitudinal end of the land portion 33 are located further outward in the longitudinal direction of the steam passage 51 (positive side in the X direction) than the first endpoint 39g. On the other hand, the protrusions 64 of the row of protrusions 63 located at the other end of the land portion 33 in the width direction (the end on the side of the second endpoint 39h) do not extend toward the support portion 39. That is, at the end on the side of the second endpoint 39h, the protrusions 64 located at the longitudinal end of the land portion 33 are located further inward in the longitudinal direction of the steam passage 51 (negative side in the X direction) than the second endpoint 39h.

[0210] According to this modified configuration, the working fluid 2b remaining on the support portion 39 can be efficiently drawn into the liquid flow path portion 60 at one end (first endpoint 39g) in the width direction of the land portion 33. On the other hand, at the other end (second endpoint 39h) in the width direction of the land portion 33, the volume of the steam passage 51 is increased, so the pressure of the working steam 2a can be reduced in this region. In particular, when the support portion 39 is located near the evaporation region SR, it is possible to suppress a rapid increase in the pressure in the space around the support portion 39 due to the working steam 2a generated in the evaporation region SR.

[0211] In this embodiment, unlike the first embodiment, a bridge 41 is not provided in the steam flow path section 50. However, the embodiment is not limited to this, and a bridge 41 may be provided in the steam flow path section 50.

[0212] (Third embodiment) Next, a third embodiment will be described with reference to Figures 39 to 44. Figures 39 to 44 show the third embodiment. The third embodiment shown in Figures 39 to 44 differs from the second embodiment mainly in that the protrusion 64 located at the longitudinal end of the land portion 33 is spaced apart from the support portion 39. In Figures 39 to 44, the same reference numerals are used for parts that are the same as those shown in Figures 1 to 38, and detailed descriptions are omitted.

[0213] As shown in Figures 39 and 40, the wick sheet 30 according to this embodiment comprises a first main body surface 31a, a second main body surface 31b, a frame portion 32, a plurality of land portions 33, and a support portion 39. Steam passages 51 through which working steam 2a passes are formed between the plurality of land portions 33. A liquid flow path portion 60 is formed on the second main body surface 31b side of at least one land portion 33, communicating with the steam passage 51 and through which working fluid 2b passes. The liquid flow path portion 60 has a plurality of liquid flow main grooves 61 through which working fluid 2b passes and which are arranged parallel to each other. Rows of protrusions 63 are provided between adjacent liquid flow main grooves 61. Each row of protrusions 63 has a plurality of protrusions 64. The protrusions 64 located at the longitudinal ends of the land portions 33 are spaced apart from the support portion 39.

[0214] Figure 40 is an enlarged top view (enlarged view of section XL in Figure 39) showing the frame portion 32 and support portion 39 located on the evaporation region SR side, and Figure 41 is an enlarged cross-sectional view (cross-sectional view along line XLI-XLI in Figure 40) showing the frame portion 32 and support portion 39. Here, in order to clarify the drawing, Figure 40 shows the liquid flow channel main groove 61 and the row of protrusions 63 in an enlarged view, and the number of these liquid flow channel main grooves 61 and row of protrusions 63 may differ from other figures for convenience. Also, in Figure 40, the injection channel 37 and other elements are omitted from the display.

[0215] As shown in Figure 40, the support portion 39 is located on the evaporation region SR side and is provided at the longitudinal end (X-direction minus side) of the land portion 33. As described above, this support portion 39 connects the land portion 33 to the frame portion 32. The frame portion 32 also has an inner wall surface 32a located on the side of the support portion 39.

[0216] As shown in Figure 41, the support portion 39 has a support portion surface 39a, a support portion inner wall surface 39b, a support portion connecting surface 39c, and a support portion back surface 39d. Of these, the support portion surface 39a is the surface located on the side of the second main body surface 31b and is a flat surface parallel to the second main body surface 31b. The support portion inner wall surface 39b is the surface facing the steam passage 51 side (positive X direction side) of the steam flow channel portion 50 and extends from the support portion surface 39a to the support portion back surface 39d. The support portion inner wall surface 39b is a curved surface, and in its cross-section, it is curved such that the side on the first main body surface 31a is located further inward in the longitudinal direction of the steam passage 51 (positive X direction side) than the side on the second main body surface 31b. The support portion inner wall surface 39b is formed to be continuous with the first wall surface 53a and the second wall surface 54a of the steam passage 51 (see Figure 40). The support section connecting surface 39c is formed to be continuous with the inner wall surface 32a of the frame section 32. The support section connecting surface 39c is a curved surface, and in its cross-section, the side facing the first main body surface 31a is curved so that it is located further inward in the longitudinal direction (positive X direction) of the steam passage 51 than the side facing the second main body surface 31b. The back surface 39d of the support section is a surface facing the first main body surface 31a and is a flat surface located on the same plane as the first main body surface 31a. Furthermore, an intersection line 39e is provided between the inner wall surface 39b of the support section and the back surface 39d of the support section. Note that the inner wall surface 39b of the support section and the support section connecting surface 39c do not necessarily have to be curved surfaces; they may also be flat surfaces. It is preferable that the inner wall surface 39b of the support section and the support section connecting surface 39c are inclined surfaces. It is also preferable that the angle between the back surface 39d of the support section and the inner wall surface 39b of the support section at the intersection line 39e is acute.

[0217] As shown in Figure 40, of the multiple protrusions 64 formed on the land portion 33, the protrusions 64 located at the longitudinal (X-direction) end of the land portion 33 are spaced apart from the support portion 39 toward the longitudinal side (X-direction positive side) of the land portion 33. In other words, the protrusions 64 located at the longitudinal end of the land portion 33 are not placed on the support portion 39, but are spaced apart from the support portion 39. As described above, each land portion 33 has multiple rows of protrusions 63 (four rows in Figure 40). In this case, all of the multiple rows of protrusions 63 formed on the land portion 33 are spaced apart from the support portion 39 by the same length L7. This length L7 spaced apart from the support portion 39 may be 50% to 200% of the width w6 of the support portion 39. The width w6 of the support portion 39 may be 50 μm to 200 μm.

[0218] As shown in Figure 41, at a position away from the support portion 39, the protrusion 64 extends from the liquid flow channel main groove 61 toward the second main body surface 31b. In this case, the bottom surface of the liquid flow channel main groove 61 formed in the land portion 33 is located on the same plane as the support portion surface 39a. However, the bottom surface of the liquid flow channel main groove 61 may be offset from the support portion surface 39a in the thickness direction (Z direction) of the land portion 33.

[0219] In this specification, "the convex portion 64 is positioned spaced apart from the support portion 39" means that the convex portion 64 located at the outermost longitudinal end of the land portion 33 is located further inward in the land portion 33 than the portion of the support portion 39 adjacent to the land portion 33 that is located furthest inward in the steam passage 51. "Support portion 39 adjacent to the land portion 33" refers to the region of the support portion 39 located between the land portion 33 and the land portion 33 adjacent to it. In Figure 40, the convex portion 64 located furthest towards the frame portion 32 (negative X direction) of the land portion 33 is located further inward in the land portion 33 (positive X direction) than the intersection line 39e, which is the innermost portion of the adjacent support portion 39. Furthermore, the length L7 mentioned above refers to the distance between the protrusion 64 located at the outermost end of the land portion 33 in the longitudinal direction and the part of the support portion 39 that is located furthest inward in the longitudinal direction of the steam passage 51 (intersection line 39e), measured along the longitudinal direction of the land portion 33.

[0220] In this embodiment, the convex portion 64 located at the longitudinal end (X-direction negative end) of the land portion 33 on the evaporation region SR side (X-direction negative side) is positioned spaced apart from the support portion 39. In other words, the steam passage 51 located between adjacent land portions 33 extends into the support portion 39 side. As a result, the volume of the steam passage 51 is expanded near the longitudinal end of the land portion 33 (indicated by AR in Figure 40), and the pressure of the working steam 2a in this region AR can be reduced. In particular, when the support portion 39 is located near the evaporation region SR, it is possible to suppress a rapid increase in pressure in the space surrounding the support portion 39 due to the working steam 2a generated in the evaporation region SR. Furthermore, by extending the steam passage 51 into the support portion 39 side, evaporation of the working steam 2a from the end of the land portion 33 can be promoted. Therefore, the recirculation of the working fluids 2a and 2b within the sealed space 3 is promoted, the flow of the working fluids 2a and 2b is not obstructed, and the uniformity of the vapor chamber 1 can be improved.

[0221] The vapor chamber 1 and wick sheet 30 according to this embodiment can be manufactured in substantially the same manner as in the first embodiment, except that a bridge 41 is not formed (see Figure 11).

[0222] Next, we will describe the operation of this embodiment, which has the above configuration.

[0223] While using the vapor chamber 1 according to this embodiment, the working fluid 2b on the land portion 33 evaporates in the vicinity of the evaporation region SR due to heat from the device D. As the working fluid 2b evaporates, it changes into working vapor 2a, and its volume expands rapidly. In contrast, according to this embodiment, the protrusion 64 located at the longitudinal end of the land portion 33 is spaced apart from the support portion 39. As a result, the working vapor 2a generated on the land portion 33 is not obstructed by the protrusion 64 and is quickly flowed into the adjacent steam passage 51 in the width direction (Y direction) of the land portion 33 (see reference numeral 2a in Figure 40). In addition, a wide space region AR of the steam passage 51 exists between adjacent land portions 33. As a result, the working vapor 2a generated on the land portion 33 is quickly released into region AR of the steam passage 51, and a rapid increase in pressure within the space on the land portion 33 can be suppressed.

[0224] Furthermore, by suppressing the pressure rise in the space above the land portion 33, deformation of the upper sheet 20 due to the force when the working fluid 2b evaporates on the land portion 33 is suppressed. This prevents a decrease in the flatness of the second upper sheet surface 20b of the upper sheet 20 to which the device D is attached, and prevents the formation of a gap between the second upper sheet surface 20b and the device D. As a result, the inhibition of heat conduction from the device D is suppressed, and the performance degradation of the vapor chamber 1 is suppressed.

[0225] Furthermore, according to this embodiment, the inner wall surface 39b of the support portion 39 is curved such that, in its cross-section, the side facing the first main body surface 31a is located more towards the inside of the steam passage 51 in the longitudinal direction (positive X direction) than the side facing the second main body surface 31b. This allows the working fluids 2a and 2b to flow smoothly from the support portion 39 into the steam passage 51, thereby promoting the recirculation of the working fluids 2a and 2b within the vapor chamber 1.

[0226] Furthermore, according to this embodiment, the support portion connecting surface 39c of the support portion 39 is curved such that, in its cross-section, the side facing the first main body surface 31a is located more towards the inside of the steam passage 51 in the longitudinal direction (positive X direction) than the side facing the second main body surface 31b. This allows the working fluids 2a and 2b to flow smoothly from the frame portion 32 through the support portion 39 into the steam passage 51, thereby promoting the recirculation of the working fluids 2a and 2b within the vapor chamber 1.

[0227] (modified version) Next, various modifications of this embodiment will be described with reference to Figures 42 to 44. Figures 42 to 44 are enlarged top views showing a part of the wick sheet 30 according to each modification. In Figures 42 to 44, the same reference numerals are used for parts that are the same as those shown in Figures 40 and 41, and detailed descriptions are omitted.

[0228] (First variation) As shown in Figure 42, at the longitudinal end of the steam passage 51 (the negative X-direction end), the intersection line 39e of the support parts 39 located at both ends in the width direction (Y-direction) of the steam passage 51 may be curved in plan view. That is, at each end in the width direction of the steam passage 51, the intersection line 39e of the support parts 39 curves toward the longitudinal side (positive X-direction) of the steam passage 51 in plan view as it moves from the inside to the outside in the width direction (Y-direction) of the steam passage 51. The intersection line 39e of the support parts 39 may be arc-shaped or elliptical arc-shaped in plan view, or it may be a shape in plan view where a line segment has curves connected to both sides of it.

[0229] According to this modified example, the working steam 2a can flow smoothly between the support portion 39 and the steam passage 51 via the curved portions located at both ends in the width direction of the inner wall surface 39b of the support portion 39 (see reference numeral 2a in Figure 42). As a result, the working steam 2a accumulated on the support portion 39 can be efficiently transferred into the steam passage 51 via the inner wall surface 39b of the support portion. This further promotes the recirculation of the working fluids 2a and 2b within the sealed space 3.

[0230] (Second variation) As shown in Figures 43(a) and 43(b), the longitudinal (X-direction) end of the steam passage 51 may reach the frame portion 32.

[0231] For example, as shown in Figure 43(a), the longitudinal end (X-direction negative end) of the steam passage 51 extends to the inner wall surface 32a of the frame portion 32, and the support portion 39 may be divided by each steam passage 51. In this case, the support portion 39 includes a plurality of connecting portions 39j. Each connecting portion 39j is located at the longitudinal end (X-direction negative end) of the land portion 33 and connects the corresponding land portion 33 and the frame portion 32 to each other. The steam passage 51 is formed between adjacent connecting portions 39j.

[0232] This allows the volume of the steam passage 51 to be further increased near the longitudinal end of the land portion 33 (indicated as AR in Figure 43(a)), thereby lowering the pressure of the working steam 2a in this region AR. In particular, when the support portion 39 is located near the evaporation region SR, it is possible to suppress a rapid increase in pressure in the space surrounding the support portion 39 due to the working steam 2a generated in the evaporation region SR. Furthermore, by extending the steam passage 51 towards the support portion 39, evaporation of the working steam 2a from the end of the land portion 33 can be promoted.

[0233] As shown in Figure 43(b), in the widthwise (Y-direction) cross-section of the land portion 33, the connecting portion 39j has a support portion side surface 39k facing the steam passage 51 side (Y-direction side). The support portion side surface 39k extends from the support portion surface 39a to the support portion back surface 39d. The support portion side surface 39k is a curved surface, and in its cross-section, it is curved such that the first main body surface 31a side is located inward in the widthwise (Y-direction) of the steam passage 51 than the second main body surface 31b side. This allows the working steam 2a to flow smoothly between the support portion 39 (connecting portion 39j) and the steam passage 51 via the curved support portion side surface 39k (see reference numeral 2a in Figure 43(b)). This allows the working steam 2a accumulated on the support portion 39 to be efficiently transferred into the steam passage 51 via the support portion side surface 39k. As a result, the recirculation of the working fluids 2a and 2b within the sealed space 3 can be further promoted. In this modified example, the cross-sectional shape of the connecting portion 39j in the width direction (Y direction) of the land portion 33 may differ from the cross-sectional shape of the land portion 33.

[0234] (Third variation) As shown in Figures 44(a) and 44(b), the length L4 (dimension in the X direction) of the protrusion 64 located at the longitudinal (X direction) end of the land portion 33 may differ from the length L1 (dimension in the X direction) of the other protrusions 64.

[0235] For example, as shown in Figure 44(a), the length L4 of the protrusion 64A (64) located at the longitudinal end of the land portion 33 may be longer than the length L1 of the other protrusions 64 (L4 > L1). As a result, capillary force acts on the longer protrusion 64A, which suppresses the adhesion of the working fluid 2b around the protrusion 64A and allows the working fluid 2b to be efficiently returned to the fluid flow channel 60. Therefore, in a thermal cycle test in which heating and cooling are repeated, expansion of the vapor chamber 1 in the region of the support portion 39 can be suppressed.

[0236] In FIG. 44(a), the length L4 of the convex portion 64A located at the longitudinal end of a part of the convex portion rows 63 is longer than the length L1 of the other convex portions 64. On the other hand, the length of the convex portions 64 located at the longitudinal end of some other convex portion rows 63 is the same as the length L1 of the other convex portions 64. However, not limited to this, the length L4 of the convex portion 64A located at the longitudinal end of all the convex portion rows 63 may be longer than the length L1 of the other convex portions 64.

[0237] Also, as shown in FIG. 44(b), the lengths L5, L6 of the convex portions 64B(64), 64C(64) located at the longitudinal ends of the land portion 33 may be shorter than the length L1 of the other convex portions 64 (L5 < L1, L6 < L1). Thereby, in the vicinity of the support portion 39, since the areas of the main flow groove 61 and the communication groove 65 of the liquid flow path of the liquid flow path portion 60 are widened, the evaporation of the working fluid 2b on the land portion 33 can be promoted.

[0238] In FIG. 44(b), the lengths L5, L6 of the convex portions 64B, 64C located at the longitudinal ends of all the convex portion rows 63 are shorter than the length L1 of the other convex portions 64. However, not limited to this, the length L1 of the convex portions 64 located at the longitudinal end of some of the convex portion rows 63 may be the same as the length L1 of the other convex portions 64.

[0239] Note that, in the present embodiment, different from the first embodiment, the bridge 41 is not provided in the vapor flow path portion 50, but not limited to this, the bridge 41 may be provided in the vapor flow path portion 50.

[0240] The present disclosure is not limited to the above-described embodiments and each modification as they are, and at the implementation stage, the components can be modified and embodied without departing from the gist thereof. Also, various inventions can be formed by appropriately combining a plurality of components disclosed in the above-described embodiments and each modification. Some components may be deleted from all the components shown in each embodiment and each modification.

Claims

1. A vapor chamber in which a working fluid is sealed, The first sheet and, The first sheet comprises a wick sheet laminated on top of the first sheet, The aforementioned wick sheet is The first main surface and A second body surface located on the opposite side from the first body surface, Frame body and Within the frame portion, there are a plurality of land portions provided at intervals from each other, The frame has support parts that support the longitudinal ends of the plurality of land parts, Between the plurality of land portions, a steam passage is formed that penetrates the first body surface and the second body surface, through which the steam of the working fluid passes. At least one of the land portions is formed on the second main body surface side, through which the liquid working fluid passes in communication with the steam passage, The liquid flow channel section has a plurality of liquid flow channel main grooves through which the liquid working fluid passes and which are arranged parallel to each other. Rows of protrusions are provided between adjacent main channels of the liquid flow path, and each row of protrusions has multiple protrusions. Of the plurality of protrusions, the protrusion located at the longitudinal end of the land portion extends toward the support portion, forming a vapor chamber.

2. A vapor chamber in which a working fluid is sealed, The first sheet and, The first sheet comprises a wick sheet laminated on top of the first sheet, The aforementioned wick sheet is The first main surface and A second body surface located on the opposite side from the first body surface, Frame body and Within the frame portion, there are a plurality of land portions provided at intervals from each other, The frame has support parts that support the longitudinal ends of the plurality of land parts, Between the plurality of land portions, a steam passage is formed, extending from the first main body surface to the second main body surface, through which the steam of the working fluid passes. At least one of the land portions is formed on the second main body surface side, through which the liquid working fluid passes in communication with the steam passage, The liquid flow channel section has a plurality of liquid flow channel main grooves through which the liquid working fluid passes and which are arranged parallel to each other. Rows of protrusions are provided between adjacent main channels of the liquid flow path, and each row of protrusions has multiple protrusions. A vapor chamber in which, among the plurality of protrusions, the protrusions located at the longitudinal end of the land portion are spaced apart from the support portion.

3. The support portion has a support portion surface located on the second main body side, a support portion back surface located on the first main body side, and an inner wall surface of the support portion extending from the support portion surface to the support portion back surface. The vapor chamber according to claim 1 or 2, wherein the inner wall surface of the support portion is located more inward in the longitudinal direction of the steam passage on the side of the first main body than on the side of the second main body in cross-section.

4. The support portion has a support portion surface located on the second main body side, a support portion back surface located on the first main body side, and a support portion connecting surface formed to be continuous with the inner wall surface of the frame portion. The vapor chamber according to any one of claims 1 to 3, wherein the support connecting surface is located more inward in the longitudinal direction of the steam passage than the second main body surface in cross-section, on the first main body surface side.

5. The support portion has a support portion surface located on the second main body side, a support portion back surface located on the first main body side, and an inner wall surface of the support portion extending from the support portion surface to the support portion back surface. A line can be drawn between the inner wall surface of the support part and the back surface of the support part. The vapor chamber according to any one of claims 1 to 4, wherein, at the widthwise end of the steam passage, the intersection line, in a plan view, curves toward the longitudinal side of the steam passage as it moves from the inside to the outside in the widthwise direction of the steam passage.

6. The vapor chamber according to any one of claims 1 to 5, wherein the length of the protrusion located at the longitudinal end of the land portion is longer than the length of the other protrusions.

7. The vapor chamber according to any one of claims 1 to 5, wherein the length of the protrusion located at the longitudinal end of the land portion is shorter than the length of the other protrusions.

8. The vapor chamber according to claim 1, wherein the liquid flow channel has a plurality of rows of protrusions, and the protrusions located at the longitudinal ends of some of the rows of protrusions extend toward the support portion, while the protrusions located at the longitudinal ends of other rows of protrusions do not extend toward the support portion.

9. The support portion has a support portion surface located on the second main body side, a support portion back surface located on the first main body side, and an inner wall surface of the support portion extending from the support portion surface to the support portion back surface. A line can be drawn between the inner wall surface of the support part and the back surface of the support part. When the intersection point between the side surface located at one end of the land portion in the width direction and the intersection line is defined as the first endpoint, and the intersection point between the side surface located at the other end of the land portion in the width direction and the other intersection line is defined as the second endpoint, On the first endpoint side, the protrusion located at the longitudinal end of the land portion is located further outward in the longitudinal direction of the steam passage than the first endpoint. The vapor chamber according to claim 1, wherein, on the second endpoint side, the protrusion located at the longitudinal end of the land portion is located longitudinally inward of the steam passage than the second endpoint.

10. The vapor chamber according to claim 2, wherein the longitudinal end of the steam passage extends to the frame portion, and the support portion is divided by the steam passage.

11. Housing and The device housed within the aforementioned housing, An electronic device comprising a vapor chamber according to any one of claims 1 to 10, which is in thermal contact with the device.

12. A wick sheet for a vapor chamber, The first main surface and A second body surface located on the opposite side from the first body surface, Frame body and Within the frame portion, there are a plurality of land portions provided at intervals from each other, The system includes support parts that support the longitudinal ends of the plurality of land portions on the frame, Between the plurality of land portions, a steam passage is formed that penetrates the first body surface and the second body surface, through which the steam of the working fluid passes. At least one of the land portions is formed on the second main body surface side, through which the liquid working fluid passes in communication with the steam passage, The liquid flow channel section has a plurality of liquid flow channel main grooves through which the liquid working fluid passes and which are arranged parallel to each other. Rows of protrusions are provided between adjacent main channels of the liquid flow path, and each row of protrusions has multiple protrusions. Of the multiple protrusions, the protrusions located at the longitudinal end of the land portion extend toward the support portion, in the wick sheet.

13. A wick sheet for a vapor chamber, The first main surface and A second body surface located on the opposite side from the first body surface, Frame body and Within the frame portion, there are a plurality of land portions provided at intervals from each other, The system includes support parts that support the longitudinal ends of the plurality of land portions on the frame, Between the plurality of land portions, a steam passage is formed, extending from the first main body surface to the second main body surface, through which the steam of the working fluid passes. At least one of the land portions is formed on the second main body surface side, through which the liquid working fluid passes in communication with the steam passage, The liquid flow channel section has a plurality of liquid flow channel main grooves through which the liquid working fluid passes and which are arranged parallel to each other. Rows of protrusions are provided between adjacent main channels of the liquid flow path, and each row of protrusions has multiple protrusions. A wick sheet in which, among the plurality of protrusions, the protrusions located at the longitudinal end of the land portion are spaced apart from the support portion.

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