Vapor chamber, wick sheet for vapor chamber, and electronic device

Abstract

A wick sheet (30) for a vapor chamber (1) comprises: a first body surface (31a); a second body surface (31b) located on the reverse side from the first body surface (31a); a frame portion (32), and a plurality of land portions (33) provided within the frame portion (32) and spaced from each other. A vapor passage (51) through which the vapor (2a) of working fluid passes is formed between the plurality of land portions (33), and a liquid flow path (60) is formed on the second body surface (31b) side of at least one of the land portions (33), the liquid flow path (60) communicating with the vapor passage (51) and allowing liquid working fluid (2b) to pass therethrough. A bridge (41) for connecting a land portion (33) and the frame portion (32) or connecting the land portions (33) to each other is provided. The bridge (41) is thinned from the first body surface (31a) side and / or the second body surface (31b) side.　

Description

Vapor chamber, wick sheet for vapor chamber, and electronic device

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

[0002] Central processing units (CPUs), light-emitting diodes (LEDs), power semiconductors, and the like used in mobile devices such as handheld devices and tablet computers are devices that generate heat. These devices are cooled by heat dissipation components such as heat pipes. In recent years, thinner heat dissipation components have been required to reduce the thickness of mobile devices. For this reason, vapor chambers, which can be made thinner than heat pipes, have been developed. A working fluid is sealed within the vapor chamber. This working fluid absorbs and dissipates the heat from the device, thereby cooling it. For example, Patent Document 1 discloses a sheet-type heat pipe made of two or more stacked metal foil sheets.

[0003] More specifically, the working fluid in the vapor chamber receives heat from the device in the portion (evaporator) close to the device and evaporates into vapor (working vapor). The working vapor diffuses in the vapor channel portion away from the evaporator, cools, and condenses into liquid. A liquid channel portion with a capillary structure (wick) is provided in the vapor chamber. The condensed working fluid (working liquid) enters the liquid channel portion from the vapor channel portion and flows through the liquid channel portion toward the evaporator. The working liquid then receives heat again in the evaporator and evaporates. In this way, the working fluid circulates within the vapor chamber while repeatedly changing phases, i.e., evaporating and condensing, thereby transferring heat from the device and improving heat dissipation efficiency.

[0004] JP 2016-017702 A Patent No. 6587164 A

[0005] The present embodiment provides a vapor chamber, a wick sheet for a vapor chamber, and an electronic device that can suppress deformation of the wick sheet.

[0006] The present embodiment also provides a vapor chamber, a wick sheet for a vapor chamber, and an electronic device that can promote the reflux of the working fluid within the vapor chamber.

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

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

[0009] In the wick sheet according to this embodiment, the plurality of land portions may include first land portions that extend linearly in a planar view, and second land portions that are curved or bent linearly in a planar view.

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

[0011] In the wick sheet according to this embodiment, the bridge has a top surface located on the second main body surface side, a bottom surface located on the first main body surface side, and a side surface located between the top surface and the bottom surface and facing in a direction opposite to the flow direction of the vapor of the working fluid in the vapor 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 liquid flow path portion has a plurality of liquid flow path main grooves through which the liquid working fluid passes, and a plurality of liquid flow path connecting grooves that communicate with the liquid flow path main grooves, and the bridge may be in contact with the liquid flow path connecting groove that is located outermost in the width direction of the land portion.

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

[0014] In the wick sheet according to this embodiment, a plurality of the communicating recesses may be formed on the top surface of the bridge, and a first communicating flow path may be formed on the top surface, connecting adjacent communicating recesses.

[0015] In the wick sheet according to this embodiment, a second communication flow path that connects 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 may include a first land portion and a second land portion, and the bridge may connect one end of the first land portion to a position midway through the second land portion, so that the liquid flow path main groove of the first land portion and the communicating recess of the bridge extend continuously.

[0017] In the wick sheet according to this embodiment, the bridge has a top surface located on the second main body surface side and a bottom surface located on the first main body surface side, and the width of the bridge may gradually increase from the top surface to 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 and second sheets. The wick sheet comprises a first main body surface, a second main body surface located opposite the first main body surface, a frame portion, and a plurality of land portions spaced apart within the frame portion. Between the plurality of land portions, a vapor passage extending from the first main body surface to the second main body surface is formed, through which vapor of the working fluid passes. A liquid flow path portion communicating with the vapor passage and through which the liquid working fluid passes is formed on the second main body surface side of at least one of the land portions. A bridge is provided to connect the land portion and the frame portion, or to connect the land portions together. 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 includes a housing, a device accommodated in the housing, and the vapor chamber according to this embodiment in thermal contact with the device.

[0021] According to the embodiments of the present 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 to the first main body surface, a frame body portion, a plurality of land portions provided within the frame body portion and spaced apart from one another, and a support portion that supports longitudinal ends of the plurality of land portions on the frame body portion, wherein a vapor passage that penetrates the first main body surface and the second main body surface and through which vapor of the working fluid passes is formed between the plurality of lands, and a liquid flow path portion that communicates with the vapor passage and through which the liquid working fluid passes is formed on the second main body surface side of at least one of the land portions, and the liquid flow path portion has a plurality of liquid flow path mainstream grooves that pass through the liquid working fluid and are arranged parallel to each other, and a convex portion row is provided between adjacent liquid flow path mainstream grooves, and each convex portion row has a plurality of convex portions, and of the plurality of convex portions, the convex portions 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 to the first main body surface, a frame body portion, a plurality of land portions provided within the frame body portion and spaced apart from one another, and a support portion that supports longitudinal ends of the plurality of land portions on the frame body portion, wherein a vapor passage extending from the first main body surface to the second main body surface and through which vapor of the working fluid passes is formed between the plurality of lands, and a liquid flow path portion that communicates with the vapor passage and through which the liquid working fluid passes is formed on the second main body surface side of at least one of the land portions, and the liquid flow path portion has a plurality of liquid flow path mainstream grooves through which the liquid working fluid passes and that are arranged parallel to one another, and a convex portion row is provided between adjacent liquid flow path mainstream grooves, and each convex portion row has a plurality of convex portions, and of the plurality of convex portions, the convex portions located at the longitudinal ends of the land portions are arranged spaced apart from the support portion.

[0024] In the wick sheet according to this 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, and the support portion inner wall surface may be located longitudinally more inward of the steam passage on the first main body surface side than on the second main body surface side in cross section.

[0025] In the wick sheet according to this 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 connecting surface formed so as to be continuous with the inner wall surface of the frame body portion, and the support portion connecting surface may be located longitudinally more inward of the steam passage on the first main body surface side than on the second main body surface side in cross section.

[0026] In the wick sheet according to this 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, and an intersection line can be drawn between the support portion inner wall surface and the support portion back surface, and at the widthwise end of the steam passage, the intersection line may be curved inward in the longitudinal direction of the steam passage as it moves from the inside in the widthwise direction of the steam passage to the outside, in a plan view.

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

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

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

[0030] In the wick sheet according to this 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, and an intersection line can be drawn between the support portion inner wall surface and the support portion back surface, and when the intersection point between the side surface located at one widthwise end of the land portion and the intersection line is defined as a first endpoint, and the intersection point between the side surface located at the other widthwise end of the land portion and the other intersection line is defined as a second endpoint, on the first endpoint side, the convex portion located at the longitudinal end of the land portion may be located longitudinally outer of the steam passage than the first endpoint, and on the second endpoint side, the convex portion located at the longitudinal end of the land portion may be located longitudinally inner of the steam passage than the second endpoint.

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

[0032] The vapor chamber according to this embodiment is a vapor chamber in which a working fluid is sealed, and includes a first sheet, a second sheet, and a wick sheet interposed between the first sheet and the second sheet. The wick sheet has a first main body surface, a second main body surface located on the opposite side to the first main body surface, a frame portion, a plurality of land portions provided in the frame portion and spaced apart from one another, and a support portion that supports longitudinal ends of the plurality of land portions on the frame portion. a liquid flow path section, which is connected to the vapor passage and through which the liquid working fluid passes, is formed on the second body surface side of at least one of the land sections, the liquid flow path section having a plurality of liquid flow path mainstream grooves, through which the liquid working fluid passes and which are arranged parallel to each other; rows of convex sections are provided between adjacent liquid flow path mainstream grooves, each row of convex sections having a plurality of convex sections; and among the plurality of convex sections, the convex sections located at the longitudinal end of the land section extend toward the support section.

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

[0034] The electronic device according to this embodiment includes a housing, a device accommodated in the housing, and the vapor chamber according to this embodiment in thermal contact with the device.

[0035] According to an embodiment of the present disclosure, the reflux of the working fluid within the vapor chamber can be promoted.

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

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

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

[0039] 1 to 10 , a vapor chamber, a wick sheet for a vapor chamber, and an electronic device according to the present embodiment will be described. The vapor chamber 1 according to the present embodiment is a device mounted on an electronic device E to cool a device D, which serves as a heat-generating body housed in the electronic device E. Examples of the device D include electronic devices (cooled devices) that generate heat and are used in mobile devices such as portable 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, an electronic device E equipped with a vapor chamber 1 according to this embodiment will be described, taking a tablet terminal as an example. As shown in FIG. 1 , the electronic device E (e.g., a tablet terminal) includes a housing H, a device D housed within the housing H, and a vapor chamber 1. In the electronic device E shown in FIG. 1 , a touch panel display TD is provided on the front surface of the housing H. The vapor chamber 1 is housed within the housing H and positioned so as to be in thermal contact with the device D. This allows the vapor chamber 1 to receive heat generated by the device D when the electronic device E is in use. The heat received by the vapor chamber 1 is dissipated to the outside of the vapor chamber 1 via working fluids 2a and 2b, which will be described later. In this manner, the device D is effectively cooled. When the electronic device E is a tablet terminal, the device D corresponds to a central processing unit or the like.

[0041] Next, a vapor chamber 1 according to this embodiment will be described. As shown in FIGS. 2 and 3 , the vapor chamber 1 has a sealed space 3 in which working fluids 2a and 2b are sealed. The vapor chamber 1 is configured to effectively cool the device D of the electronic device E described above by repeatedly changing the phases of the working fluids 2a and 2b in the sealed space 3. Examples of the working fluids 2a and 2b include pure water, ethanol, methanol, acetone, etc., and mixtures thereof. The working fluids 2a and 2b may have freeze-expansion properties. In other words, the working fluids 2a and 2b may be fluids that expand when frozen. Examples of the freeze-expansion working fluids 2a and 2b include pure water, or an aqueous solution of pure water to which an additive such as alcohol has been added.

[0042] 2 and 3, the vapor chamber 1 includes 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 a wick sheet 30). The wick sheet 30 is interposed between the lower sheet 10 and the upper sheet 20. In the vapor chamber 1 according to this embodiment, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are 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, and may be a rectangle as shown in FIG. 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. 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 a rectangle with the X direction (described later) as the longitudinal direction will be described. In this case, as shown in FIGS. 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 may be any shape, such as a circle, an ellipse, an L-shape, a T-shape, or a U-shape.

[0044] As shown in FIG. 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 an area that overlaps with the device D in a planar view and is an area where the device D is attached. The evaporation region SR can be located 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 FIG. 2 ). Heat from the device D is transferred to the evaporation region SR, and this heat causes the liquid working fluid (appropriately referred to as working fluid 2b) to evaporate in the evaporation region SR. The heat from the device D can be transferred not only to the area that overlaps with the device D in a planar view, but also to the surrounding area of ​​that area. Therefore, the evaporation region SR includes the area that overlaps with the device D and the surrounding area in a planar view. Here, the planar view refers to the state when the vapor chamber 1 is viewed from a direction perpendicular to the surface that receives heat from the 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). That is, the plan view corresponds to a state in which the vapor chamber 1 is viewed from above or below, as shown in FIG. 2, for example.

[0046] The condensation region CR is a region that does not overlap with the device D in a plan view, and is a region where the working vapor 2a mainly releases heat and condenses. The condensation region CR can also be said to be a region 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 condensed in the condensation region CR.

[0047] When the vapor chamber 1 is installed inside a mobile terminal, the up-down relationship may be lost depending on the orientation of the mobile terminal. However, in this embodiment, for convenience, the sheet that receives heat from the device D will be referred to as the upper sheet 20, and the sheet that releases the received heat will be referred to as the lower sheet 10. For this reason, the following description will be given assuming that the lower sheet 10 is positioned on the bottom and the upper sheet 20 is positioned on the top.

[0048] As shown in FIG. 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., the wick sheet 30 side). The lower sheet 10 may be formed flat overall, or may have a constant thickness overall. A housing member Ha that forms part of the housing of a mobile terminal or the like is attached to this first lower sheet surface 10a. The first lower sheet surface 10a may be entirely covered by the housing member Ha. As shown in FIG. 4 , alignment holes 12 may be provided at the four corners of the lower sheet 10.

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

[0050] 3, the wick sheet 30 includes a vapor flow path portion 50 and a liquid flow path portion 60 disposed adjacent to the vapor flow path portion 50. The wick sheet 30 also includes a first main body surface 31a and a second main body surface 31b located on the opposite side of the first main body surface 31a. The first main body surface 31a is disposed on the side of the lower sheet 10, and the second main body surface 31b is disposed 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 bonded 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 bonded to each other by diffusion bonding. Note that the lower sheet 10, the upper sheet 20, and the wick sheet 30 may be bonded by other methods, such as brazing, as long as they are permanently bonded, rather than by diffusion bonding. Note that the term "permanently bonded" is not limited to a strict meaning. "Permanently bonded" means that the lower sheet 10 and the wick sheet 30 are bonded to a degree that allows the lower sheet 10 and the wick sheet 30 to maintain their bond and the upper sheet 20 and the wick sheet 30 to maintain their bond to a degree that allows the sealed space 3 to be kept sealed during operation of the vapor chamber 1.

[0052] As shown in FIGS. 3 , 6 , and 7 , the wick sheet 30 according to this embodiment includes a frame portion 32 formed in a rectangular frame shape in a plan view and a land portion 33 provided within the frame portion 32. The frame portion 32 and the land portion 33 are portions of the wick sheet 30 that are not etched away in the etching process described below, and the material of the wick sheet 30 remains. In this embodiment, the frame portion 32 is formed in a rectangular frame shape in a plan view. However, the frame portion 32 may have any 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 around the land portion 33 inside the frame portion 32.

[0053] In this embodiment, the land portion 33 may extend in an elongated shape with the X direction (first direction, left-right direction in FIG. 6 ) as the longitudinal direction in a plan view. The planar shape of the land portion 33 is an elongated rectangular shape, but is not limited thereto. The land portion 33 may have any shape, such as an arc, a curved shape such as an S-shape, or a bent linear shape such as a V-shape or an L-shape. Furthermore, the lands 33 may be arranged parallel to each other and spaced at equal intervals in the Y direction (second direction, up-down direction in FIG. 6 ). The working steam 2a flows around each land portion 33 and is transported toward the condensation region CR. This prevents the flow of the working steam 2a from being obstructed. The width w1 (see FIG. 8 ) of the land portion 33 may be, for example, 30 μm or more and 3000 μm or less. Here, the width w1 of the land portion 33 refers to the dimension of the land portion 33 in the Y direction, and refers to the dimension at the widest position of the land portion 33 (e.g., the position where the protrusion 55 described below is present).

[0054] The frame body 32 and each land portion 33 are diffusion bonded to the lower sheet 10 and also to the upper sheet 20, thereby improving the mechanical strength of the vapor chamber 1. A first wall surface 53a and a second wall surface 54a of the vapor passage 51, which will be described later, form 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 across the frame body 32 and each land portion 33.

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

[0056] 6 and 7 , the steam flow path section 50 in this embodiment has a plurality of steam passages 51. The steam passages 51 are formed inside the frame body section 32 and outside the land sections 33, i.e., between the frame body section 32 and the land sections 33, and between adjacent land sections 33. The planar shape of each steam passage 51 is an elongated rectangular shape, but is not limited to this and may be any shape, such as an arc, a curved shape such as an S-shape, or a bent linear shape such as a V-shape or an L-shape. The steam flow path section 50 is partitioned into a plurality of steam passages 51 by the plurality of lands 33.

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

[0058] The steam passage 51 may be formed by etching the first and second body surfaces 31a and 31b of the wick sheet 30, respectively, in an etching process described below. In this case, as shown in FIG. 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 body surface 31a side and is curved in a shape concave toward the inside of the land portion 33 in the width direction (Y direction). The second wall surface 54a is located on the second body surface 31b side and is curved in a shape concave toward the inside of the land portion 33 in the width direction (Y direction). The first wall surface 53a and the second wall surface 54a meet at a protrusion 55 formed to protrude inward of the steam passage 51. The protrusion 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 protrusion 55 is present. The width w2 of the steam passage 51 (see FIG. 8 ) may be, for example, 100 μm or more and 5000 μm or less. Here, the width w2 of the steam passage 51 refers to the width at the narrowest portion of the steam passage 51, and in this case refers to the distance measured in the width direction (Y direction) at the position where the protrusion 55 is present. The width w2 of the steam passage 51 corresponds to the gap between adjacent land portions 33 in the width direction (Y direction).

[0059] The position of the protrusion 55 in the thickness direction (Z direction) of the wick sheet 30 is shifted toward the second body surface 31b from the center position between the first body surface 31a and the second body surface 31b. When the distance between the protrusion 55 and the second body surface 31b is t5 (see FIG. 8), the distance t5 may be 5% or more, 10% or more, or 20% or more of the thickness t4 (see FIG. 8) of the wick sheet 30 (described later). The distance t5 may 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 protrusion 55 in the thickness direction (Z direction) of the wick sheet 30 may be the center position between the first body surface 31a and the second body surface 31b, or may be shifted toward the first body surface 31a from the center position. The position of the protrusion 55 is arbitrary as long as the steam passage 51 penetrates the wick sheet 30 in the thickness direction (Z direction).

[0060] In addition, in this embodiment, the cross-sectional shape of the steam passage 51 is defined by the protrusion 55 formed to protrude inward, but this 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 passages 51 configured in this manner constitutes a part of the above-described sealed space 3. As shown in Fig. 3, the steam flow path section 50 according to this embodiment is defined mainly by the lower sheet 10, the upper sheet 20, and the frame portion 32 and land portion 33 of the above-described wick sheet 30. 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 flow path section 50. Some of the bridges 41 connect the land portions 33 to the frame portion 32, while other bridges 41 connect adjacent land portions 33 to each other. Specifically, the bridges 41 connect the land portion 33 to the land portion 33 or the frame portion 32 adjacent to the land portion 33 in the width direction (Y direction). Each bridge 41 is provided to cross the steam path 51 in the width direction (Y direction). In this case, one bridge 41 is provided for each steam path 51. By providing bridges 41 for all steam paths 51 in this manner, deformation of each land portion 33 can be effectively suppressed.

[0063] The position of the bridge 41 in the vapor flow path section 50 is not critical, but it is preferable to position the bridge 41 in a relatively wide portion of the vapor flow path section 50. This prevents the cross-sectional area of ​​the vapor flow path section 50 from becoming narrower at the location where the bridge 41 is located, thereby preventing the resistance of the vapor flow path section 50 from increasing. For example, if the width of a single vapor passage 51 varies along the longitudinal direction of the vapor passage 51, the bridge 41 may be provided in a relatively wide portion of the vapor passage 51. In this case, it is possible to prevent a decrease in the movement speed of the working vapor 2a across the bridge 41. Alternatively, if the widths of multiple vapor passages 51 are different from one another, the bridge 41 may be positioned in a relatively wide vapor passage 51 among the multiple vapor passages 51. In this case, it is possible to prevent the vapor chamber 1 from having a limited flow rate (low-temperature portion).

[0064] Each bridge 41 has a rectangular shape in a 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 provided at any position in the longitudinal direction (X direction) of the land portion 33. In this case, the bridge 41 is located at the middle position in the longitudinal direction of the land portion 33, between the evaporation region SR and the condensation region CR. The multiple bridges 41 are arranged in a straight line in a plan view. Specifically, the line connecting the centers of the bridges 41 is located on a straight line parallel to the width direction (Y direction) of the land portion 33. This allows the multiple lands 33 to be restrained at the same location in the longitudinal direction (X direction), thereby more effectively suppressing 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. This prevents the bridge 41 from obstructing the flow of working steam 2a in the steam passage 51.

[0066] Furthermore, the bridge 41 is thinned by half-etching from the first body surface 31a side. Therefore, when the protrusion 55 is located closer to the second body surface 31b than the first body surface 31a (see FIG. 8), the thickness of the bridge 41 can be reduced in a single etching process. This prevents the bridge 41 from increasing the vapor resistance of the vapor passage 51 or increasing the weight of the wick sheet 30. Furthermore, because the bridge 41 and the liquid flow path 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 has entered this gap can escape from the liquid flow path 60. Therefore, even if the working fluid 2b freezes in a temperature environment below the freezing point of the working fluid 2b, the frozen working fluid 2b can prevent the gap between the bridge 41 and the upper sheet 20 from widening.

[0067] As shown in FIG. 8 , the bridge 41 has a top surface 41b located on the second body surface 31b side and a bottom surface 41a located on the first body surface 31a side. The top surface 41b is flat and located on the same plane as the second body surface 31b. The entire 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 formed by etching from the first body surface 31a side and may be curved toward the second body surface 31b side. The bridge 41 may also be formed at the same time as the steam passage 51 is formed by etching. In this case, the bottom surface 41a is curved and extends continuously from the first wall surface 53a of the steam passage 51. The thickness t6 of the bridge 41 (at its thinnest point) may be 5% or more, 10% or more, or 20% or more of the thickness t4 of the wick sheet 30 (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] 9 , the bridge 41 has a side surface 41c between the top surface 41b and the 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 be a flat surface perpendicular to the longitudinal direction (X direction) of the steam passage 51.

[0069] In this way, by connecting the land portions 33 to other land portions 33 or the frame portion 32 with the bridges 41, the length of the elongated space (part of the vapor 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 blind in one direction (X direction). As a result, the wick sheet 30 is less likely to deform during handling, improving the handleability of the wick sheet 30 during the manufacture of the vapor chamber 1. Furthermore, the flatness of the completed wick sheet 30 can be improved, improving the quality of the vapor chamber 1.

[0070] Alternatively, the bridge 41 may be thinned by half-etching from the second body surface 31b side ( FIG. 10( a) ). In this case, the bridge 41 is not present on the second body surface 31b side, allowing the working vapor 2a or working liquid 2b to smoothly flow between the vapor passage 51 and the liquid flow path portion 60. Furthermore, the working liquid 2b that accumulates on the top surface 41b of the bridge 41 can be easily collected. 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 ( FIG. 10( b) ). In this case, the bridge 41 is positioned approximately in the center between the first body surface 31a and the second body surface 31b in the thickness direction. This prevents the bridge 41 from easily breaking from only one of the first body surface 31a and the second body surface 31b.

[0071] As shown in FIGS. 6 and 7 , support portions 39 are provided within the steam flow path portion 50 to support the longitudinal (X-direction) ends of the land portions 33 on the frame portion 32. The support portions 39 support adjacent land portions 33. The support portions 39 are provided on one side (the positive X-direction side) of the land portions 33 in the longitudinal direction (X-direction). The support portions 39 may also be provided on both sides of the land portions 33 in the longitudinal direction (X-direction). The support portions 39 are preferably formed so as not to impede the flow of the working steam 2a diffusing through the steam flow path portion 50. In this case, the support portions 39 are disposed on the first main body surface 31a side of the wick sheet 30, and a space communicating with the steam flow path portion 50 is formed on the second main body surface 31b side. The support portions 39 are indicated in gray in FIG. 6 . The support portions 39 are thinned from the second main body surface 31b side by half-etching. 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 allows the support portion 39 to be thinner than the wick sheet 30, preventing the steam passage 51 from being divided in the X direction and the Y direction. However, this is not limiting, and the support portion 39 may be disposed on the second main body surface 31b side. Furthermore, spaces that communicate 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] As shown in FIG. 2 , the vapor chamber 1 may further include an injection section 4 at the edge of one side in the X direction (the negative side in the X direction) for injecting the working fluid 2b into the sealed space 3. In the embodiment shown in FIG. 2 , the injection section 4 is disposed on the evaporation region SR side. The injection section 4 has an injection flow path 37 formed in the wick sheet 30. The injection flow path 37 is formed on the second main body surface 31b side of the wick sheet 30 and is recessed from the second main body surface 31b side. After the vapor chamber 1 is completed, the injection flow path 37 is sealed. The injection flow path 37 is also connected to the vapor flow path section 50, and the working fluid 2b is injected into the sealed space 3 through the injection flow path 37. Depending on the arrangement of the liquid flow path section 60, the injection flow path 37 may be connected to the liquid flow path section 60.

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

[0074] As shown in FIGS. 3 , 6 , and 8 , the liquid flow path portion 60 is provided on the second main body surface 31 b of the wick sheet 30. The working fluid 2 b mainly flows through the liquid flow path portion 60. This liquid flow path portion 60 constitutes a part of the sealed space 3 and is connected to the vapor flow path portion 50. The liquid flow path portion 60 is configured as a capillary structure (wick) for transporting the working fluid 2 b to the evaporation region SR. In this embodiment, the liquid flow path portion 60 is provided on the second main body surface 31 b of each land portion 33 of the wick sheet 30. The liquid flow path portion 60 may be formed over the entire second main body surface 31 b of each land portion 33. Furthermore, the liquid flow path portion 60 may not be formed on some of the multiple lands 33.

[0075] 9, the liquid flow path section 60 has a plurality of liquid flow path mainstream grooves 61 through which the working fluid 2b passes and which are arranged parallel to one another, and a plurality of liquid flow path communication grooves 65 which communicate with the liquid flow path mainstream grooves 61. In the example shown in FIG. 9, each land portion 33 includes six liquid flow path mainstream grooves 61, but this is not limited to this. The number of liquid flow path mainstream grooves 61 included in each land portion 33 is arbitrary and may be, for example, 3 to 20.

[0076] 9, each liquid flow path main groove 61 is formed to extend along the longitudinal direction (X direction) of the land portion 33. The multiple liquid flow path main grooves 61 are arranged parallel to one another. If the land portion 33 is curved in plan view, each liquid flow path main groove 61 may extend in a curved shape along the curved direction of the land portion 33. In other words, each liquid flow path main groove 61 does not necessarily have to be formed linearly, and does not necessarily have to extend parallel to the X direction.

[0077] The liquid flow path mainstream grooves 61 have a flow path cross-sectional area smaller than that of the vapor passages 51 of the vapor flow path section 50 so that the working fluid 2b flows mainly by capillary action. The liquid flow path mainstream grooves 61 are configured to transport the working fluid 2b condensed from the working vapor 2a to the evaporation region SR. The liquid flow path mainstream grooves 61 are arranged at intervals from one another in the width direction (Y direction).

[0078] The liquid flow path mainstream grooves 61 are formed by etching from the second main body surface 31b of the wick sheet 30 in an etching process described below. As shown in Fig. 8, the liquid flow path mainstream grooves 61 have curved wall surfaces 62. These wall surfaces 62 define the liquid flow path mainstream grooves 61 and are 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 Fig. 8, the radius of curvature of each wall surface 62 is preferably smaller than the radius of curvature of the second wall surface 54a of the steam passage 51.

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

[0080] 8, the depth h1 of the liquid flow path mainstream groove 61 may be, for example, 3 μm or more and 300 μm or less. The depth h1 of the liquid flow path mainstream groove 61 is the distance measured from the second main body surface 31b in a direction perpendicular to the second main body surface 31b, which in this case is the dimension in the Z direction. The depth h1 also refers to the depth of the liquid flow path mainstream groove 61 at its deepest point.

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

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

[0083] Like the liquid flow path main grooves 61, the liquid flow path communication grooves 65 are also formed by etching, and have wall surfaces (not shown) formed in a curved shape similar to the liquid flow path main grooves 61. As shown in Fig. 9, the width w4 (dimension in the X direction) of the liquid flow path communication grooves 65 may be 5 µm or more and 300 µm or less. The depth of the liquid flow path communication grooves 65 may be 3 µm or more and 300 µm or less.

[0084] As shown in Fig. 9, convex rows 63 are provided between adjacent liquid flow path main grooves 61 of the liquid flow path section 60. Note that, in the example shown in Fig. 9, each land section 33 includes seven convex rows 63, but this is not limited to this. The number of convex rows 63 included in each land section 33 is arbitrary and may be, for example, 3 to 20 rows.

[0085] As shown in Fig. 9, each of the convex rows 63 is formed to extend along the longitudinal direction (X direction) of the land portion 33. The multiple convex rows 63 are arranged parallel to one another. Note that, if the land portion 33 is curved in a plan view, each of the convex rows 63 may extend in a curved shape along the curvature direction of the land portion 33. In other words, each of the convex rows 63 does not necessarily have to be formed linearly, and does not necessarily have to extend parallel to the X direction. The convex rows 63 are arranged at intervals from one another in the width direction (Y direction).

[0086] Each projection row 63 includes a plurality of projections 64 (liquid flow path protrusions) arranged in the X direction. The projections 64 are provided within the liquid flow path section 60 and project from the liquid flow path mainstream grooves 61 and the liquid flow path communication grooves 65 to abut against the upper sheet 20. Each projection 64 is formed in a rectangular shape with the X direction as its longitudinal direction in a plan view. A liquid flow path mainstream groove 61 is disposed between each projection 64 adjacent to each other in the Y direction. A liquid flow path communication groove 65 is disposed between each projection 64 adjacent to each other in the X direction. The liquid flow path communication groove 65 is formed to extend in the Y direction and connects the liquid flow path mainstream grooves 61 adjacent to each other in the Y direction. This allows the working fluid 2b to move back and forth between these liquid flow path mainstream grooves 61.

[0087] The protrusions 64 are portions that are not etched away in the etching process described below, and the material of the wick sheet 30 remains. In this embodiment, as shown in Fig. 9, the planar shape of the protrusions 64 (the shape at the position of the second main body 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 convex portions 64 are arranged in a staggered (alternate) pattern. More specifically, the convex portions 64 of the convex portion rows 63 adjacent to each other in the Y direction are arranged with a shift from each other in the X direction. This shift may be half the arrangement pitch of the convex portions 64 in the X direction. The arrangement of the convex portions 64 is not limited to a staggered pattern, and they may be arranged in parallel. In this case, the convex portions 64 of the convex portion rows 63 adjacent to each other in the Y direction are also aligned in the X direction. The bridge 41 may be integrated with some of the convex portions 64 located at the ends in the width direction (Y direction).

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

[0090] 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. However, 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, thereby improving the heat dissipation efficiency of the vapor chamber 1. Furthermore, when pure water is used as the working fluid 2a, 2b, corrosion can be prevented. However, 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 as long as the desired heat dissipation efficiency can be achieved and corrosion can be prevented.

[0091] 3 may have a thickness t1 of 100 μm or more and 2000 μm or less. By setting the thickness t1 to 100 μm or more, the vapor flow path portion 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, the thickness t1 of the vapor chamber 1 can be prevented 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, the thickness t1 of the vapor chamber 1 can be prevented from becoming too thick. Similarly, the thickness t3 of the upper sheet 20 may be set to be the same 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 making the thickness t4 50 μm or more, the vapor flow path portion 50 can be properly secured, allowing the vapor chamber 1 to function properly. On the other hand, by making the thickness t4 1000 μm or less, the thickness t1 of the vapor chamber 1 can be prevented from becoming too thick.

[0094] Next, a method for manufacturing the vapor chamber 1 according to this embodiment having the above-described configuration will be described with reference to Figures 11(a) to 11(c). Figures 11(a) to 11(c) show cross sections that are substantially the same as the cross section shown in Figure 3.

[0095] First, the manufacturing process of the wick sheet 30 will be described.

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

[0097] After the preparation step, in the etching step, the metal material sheet M is etched from the first material surface Ma and the second material surface Mb, as shown in FIG. 11(b), to form the vapor flow path portion 50 and the liquid flow path portion 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 pattern, forming the vapor flow path portion 50 and the liquid flow path portion 60 as shown in FIG. 11( b). At this time, the metal material sheet M is half-etched from the first material surface Ma side, thereby forming a bridge 41. The etching solution may be, for example, an iron chloride-based etching solution such as a ferric chloride aqueous solution, or a copper chloride-based etching solution such as a copper chloride aqueous solution.

[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 thereto, and the etching of the first material surface Ma and the second material surface Mb may be performed in separate processes. Furthermore, the vapor flow path portion 50 and the liquid flow path portion 60 may be formed by etching simultaneously or in separate processes. Furthermore, in the etching process, the first material surface Ma and the second material surface Mb of the metal material sheet M are etched to obtain a predetermined outer contour shape as shown in FIGS. 6 and 7 . That is, the edge of the wick sheet 30 is formed.

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

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

[0102] More specifically, first, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are laminated in this order. In this case, the first main body surface 31a of the wick sheet 30 is placed 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 placed on the second main body surface 31b of the wick sheet 30. At this time, the sheets 10, 20, and 30 are aligned using the alignment holes 12 (see FIG. 4) of the lower sheet 10, the alignment holes 35 (see FIGS. 6 and 7) of the wick sheet 30, and the alignment hole 22 (see FIG. 5) of the upper sheet 20.

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

[0104] Next, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are permanently bonded together by diffusion bonding. Diffusion bonding is a bonding method described below. First, the lower sheet 10 and the wick sheet 30 are brought into close contact with each other, and then the wick sheet 30 and the upper sheet 20 are brought into close contact with each other. Next, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are pressurized and heated in the stacking direction in a controlled atmosphere, such as a vacuum or an inert gas atmosphere, to bond them together by utilizing atomic diffusion that occurs at the bonding surfaces. In diffusion bonding, the materials of the sheets 10, 20, and 30 are heated to a temperature close to, but lower than, their melting points, thereby preventing the sheets 10, 20, and 30 from melting and deforming. More specifically, the frame portion 32 of the wick sheet 30 and the first main body surface 31 a of each land portion 33 are diffusion bonded to the second lower sheet surface 10 b of the lower sheet 10. Additionally, the frame portion 32 of the wick sheet 30 and the second main body surface 31b of each land portion 33 are diffusion bonded to the first upper sheet surface 20a of the upper sheet 20. In this manner, the sheets 10, 20, 30 are diffusion bonded to form a sealed space 3 having a vapor flow path portion 50 and a liquid flow path portion 60 between the lower sheet 10 and the upper sheet 20.

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

[0106] Thereafter, the above-described injection flow path 37 is sealed. For example, the injection portion 4 may be partially melted to seal the injection flow path 37. This blocks communication between the sealed space 3 and the outside, seals the working fluid 2b in the sealed space 3, and prevents the working fluid 2b in the sealed space 3 from leaking to the outside.

[0107] In this manner, the vapor chamber 1 according to this embodiment is obtained.

[0108] Next, the operation method of the vapor chamber 1, that is, the cooling method of the device D, will be described.

[0109] The vapor chamber 1 obtained as described above is installed in the housing H of an electronic device E such as a mobile terminal. A device D, such as a CPU, which is a 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). Due to its surface tension, the working fluid 2b in the sealed space 3 adheres to the wall surfaces of the sealed space 3, i.e., the first wall surface 53a and the second wall surface 54a of the vapor passage 51, the wall surface 62 of the liquid flow path mainstream groove 61 of the liquid flow path section 60, and the wall surface of the liquid flow path connecting groove 65. The working fluid 2b can also adhere to the portion of the second lower sheet surface 10b of the lower sheet 10 exposed to the vapor passage 51. Furthermore, the working fluid 2b can also adhere to the portion of the first upper sheet surface 20a of the upper sheet 20 exposed to the vapor passage 51, the liquid flow path mainstream groove 61, and the liquid flow path connecting groove 65.

[0110] In this state, when the device D generates heat, the working fluid 2b present in the evaporation region SR (see FIGS. 6 and 7 ) receives heat from the device D. The received heat is absorbed as latent heat, and the working fluid 2b evaporates (vaporizes), generating working vapor 2a. Most of the generated working vapor 2a diffuses within the vapor passages 51 that form the sealed space 3 (see the solid arrows in FIG. 6 ). The working vapor 2a in each vapor passage 51 leaves the evaporation region SR, and most of the working vapor 2a is transported to the condensation region CR (the right-hand portion in FIGS. 6 and 7 ), which has a relatively low temperature. In the condensation region CR, the working vapor 2a is cooled by radiating heat primarily to the lower sheet 10. The heat received by the lower sheet 10 from the working vapor 2a is transferred to the outside air via the housing member Ha (see FIG. 3 ).

[0111] The working vapor 2a radiates heat to the lower sheet 10 in the condensation region CR, thereby losing the absorbed latent heat and condensing in the evaporation region SR, generating working fluid 2b. The generated working fluid 2b adheres to the first wall surface 53a and the second wall surface 54a of each vapor passage 51, the second lower sheet surface 10b of the lower sheet 10, and the first upper sheet surface 20a of the upper sheet 20. Here, the working fluid 2b continues to evaporate in the evaporation region SR. Therefore, the working fluid 2b in the region of the liquid flow path section 60 other than the evaporation region SR (i.e., the condensation region CR) is transported toward the evaporation region SR by capillary action of each liquid flow path mainstream groove 61 (see dashed arrows in FIG. 6 ). As a result, the working fluid 2b adhering to each vapor passage 51, the second lower sheet surface 10b, and the first upper sheet surface 20a moves to the liquid flow path section 60, passes through the liquid flow path connecting groove 65, and enters the liquid flow path mainstream groove 61. In this way, the working fluid 2b is filled into each liquid flow path mainstream groove 61 and each liquid flow path connecting groove 65. Therefore, the filled working fluid 2b obtains a driving force toward the evaporation region SR due to the capillary action of each liquid flow path mainstream groove 61, and is smoothly transported toward the evaporation region SR.

[0112] In the liquid flow path section 60, each liquid flow path mainstream groove 61 communicates with the adjacent other liquid flow path mainstream groove 61 via the corresponding liquid flow path connection groove 65. This allows the working fluid 2b to flow back and forth between the adjacent liquid flow path mainstream grooves 61, thereby preventing dryout in the liquid flow path mainstream grooves 61. As a result, capillary action is imparted to the working fluid 2b in each liquid flow path mainstream groove 61, and the working fluid 2b is smoothly transported toward the evaporation region SR.

[0113] The working fluid 2b that reaches the evaporation region SR receives heat from the device D again and evaporates. The working vapor 2a that has evaporated from the working fluid 2b passes through the liquid flow path communication groove 65 in the evaporation region SR, moves to the vapor paths 51 with large flow path cross-sectional areas, and diffuses within each vapor path 51. In this way, the working fluids 2a and 2b circulate within the sealed space 3 while repeatedly changing phases, i.e., evaporating and condensing, and transport and release heat from the device D. As a result, the device D is cooled.

[0114] According to this embodiment, the wick sheet 30 has bridges 41 connecting the land portions 33 and the frame portion 32, and bridges 41 connecting the land portions 33 to each other. This shortens the length (length in the X direction) of the elongated space (part of the vapor passage 51) penetrating the wick sheet 30 in one direction (X direction). As a result, the land portions 33 of the wick sheet 30 are prevented from moving apart like a blind, thereby preventing deformation of the wick sheet 30 during handling. By preventing deformation of the wick sheet 30, partial narrowing or blockage of the vapor passage portion 50 and the liquid passage portion 60 can be prevented, thereby improving the cooling capacity of the vapor chamber 1. Furthermore, because the bridges 41 are thin-walled, they do not completely block the vapor passage 51, preventing the flow of the working vapor 2a within the vapor passage 51 from being obstructed.

[0115] (Modifications) Next, various modifications of the first embodiment will be described with reference to Figs. 12 to 27. Figs. 12 to 27 are views showing the wick sheet 30 or the bridge 41 according to the modifications, respectively. In Figs. 12 to 27, the same parts as those shown in Figs. 1 to 11 are designated by the same reference numerals, and detailed description thereof will be omitted. Also, in Figs. 12 to 18, for convenience, illustration of some elements such as the injection flow path 37 and the support portion 39 is omitted.

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

[0117] 12A, for example, a bridge 41 may be provided at the center position in the longitudinal direction of the land portion 33. In this case, when the length of the land portion 33 along the longitudinal direction 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] 12(b), a plurality of bridges 41 (two per steam passage 51 in this case) may be provided along the longitudinal direction of the land portion 33, with the bridges 41 being provided at positions that equally divide the length along the longitudinal direction of the land portion 33. In this case, in each steam 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 each disposed at equal intervals of da / 3.

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

[0120] According to this modification, the bridges 41 are evenly arranged along the longitudinal direction of the land portion 33, thereby reducing the length of the elongated space (part of the steam passage 51) that penetrates along the longitudinal direction of the land portion 33, and more effectively suppressing deformation of the land portion 33. Furthermore, since the number of bridges 41 can be reduced, it is possible to suppress an increase in the steam resistance of the steam passage 51 due to the bridges 41 and an increase in the weight of the wick sheet 30.

[0121] (Second Modification) 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 arranged with a shift in the longitudinal direction (X direction) of the land portion 33.

[0122] For example, as shown in FIG. 13( a), multiple land portions 33 may be arranged in a straight line in a plan view, and the line connecting the centers of multiple bridges 41 may be located 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] 13B, the bridges 41 may be arranged in a staggered pattern in plan view. That is, each bridge 41 is offset from another bridge 41 adjacent to the land 33 in the width direction (Y direction) with respect to the land 33 in the longitudinal direction (X direction).

[0124] According to this modification, even if there is slight steam resistance in the steam passage 51 near the bridge 41 and the working steam 2a accumulates at this position, heat can be transferred to the adjacent steam passage 51 via the liquid flow path 60 adjacent to the bridge 41 (see the arrows in Figures 13(a) and 13(b)). This makes it possible to suppress a decrease in the heat transport performance of the steam passage 51.

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

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

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

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

[0129] 14(a) to 14(c), no bridge 41 is provided at the middle position in the longitudinal direction of each land portion 33. Furthermore, the support portion 39 does not need to be provided inside the steam flow path portion 50. According to this modification, deformation of the land portion 33 can be suppressed while suppressing an increase in steam resistance of the steam path 51 due to the bridge 41.

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

[0131] As shown in FIG. 15( a ), the side edges 41 d of each bridge 41 may extend substantially linearly in a plan view.

[0132] 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 curved shape in a plan view, but are not limited to this and may be recessed in a rectangular shape. This allows the working steam 2a to flow more easily along the width direction (Y direction) of each land portion 33.

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

[0134] 15(d), the width (length in the Y direction) of each bridge 41 may be wider on the frame body 32 side than on the land portion 33 side. 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 linear. This makes it possible to more effectively suppress deformation of the land portion 33.

[0135] 15( e), the connection portions 32 p of the frame portion 32 that connect to the bridges 41 may extend toward the bridges 41. This makes it possible to more effectively suppress deformation of the land portions 33.

[0136] 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 linearly in plan view along the longitudinal direction (X direction) of the land portion 33. By changing the shapes of the pair of side edges 41d in this way, it is possible to achieve both 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 in which force is applied to the land portion 33.

[0137] 16(a) to 16(c), the land portions 33 may be bent linearly. In this case, the planar shape of the wick sheet 30 is L-shaped, and each land portion 33 extends linearly in the L-shape in plan view.

[0138] 16A, each bridge 41 may be disposed at a 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 portion that is prone to deformation.

[0139] 16(b), each bridge 41 may be disposed near a bent portion of the land portion 33. Specifically, the distance dc between the center of a bridge 41 and the bent portion of the land portion 33 closest to the bridge 41 may be set to be equal to or greater than 0 and equal to or less than 30 times the width w2 of the steam passage 51. This makes it possible to suppress deformation of the bent portion of the land portion 33 and to suppress an increase in steam resistance near the bent portion of the land portion 33.

[0140] 16(c), each bridge 41 may be located away from the evaporation region SR. Specifically, when viewed along the length of the land portion 33, each bridge 41 may be located closer to the condensation region CR than the evaporation region SR. In this case, each bridge 41 is provided in an area where the vapor pressure (speed of the working vapor 2a) is low, thereby suppressing an increase in the vapor resistance of the vapor passage 51 due to the bridge 41. Furthermore, 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 long. In this case, deformation of the land portion 33 can be suppressed.

[0141] 16(a) to 16(c), the angle at which the land portion 33 is bent in plan view is not limited to 90° and may be any angle from an acute angle to an obtuse angle. Also, the land portion 33 may be curved in a curved shape in plan view.

[0142] 17(a)-17(c), the land portions 33 may have curved portions R that are curved in a curved shape in a planar view. Furthermore, the vapor passages 51 located between the land portions 33 are also curved in a curved shape in a planar view, similar to the land portions 33. By having the curved portions R in the land portions 33, the vapor resistance of the working vapor 2a flowing through the vapor passages 51 can be reduced, and heat can be easily transferred within the surface of the vapor chamber 1.

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

[0144] 17(b), each bridge 41 may be disposed at the boundary between the curved portion R and the straight portion of the land portion 33. This allows the working steam 2a to easily flow through the steam passage 51 at the curved portion R, and also makes it possible to suppress deformation of the land portion 33 at the curved portion R.

[0145] 17C, each bridge 41 may be disposed approximately at the center of the curved portion R of the land portion 33. This makes it possible to suppress deformation of the land portion 33 at the curved portion R.

[0146] 18(a) to 18(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 and bent in a plan view. In this case, the planar shape of the wick sheet 30 is rectangular, but it may be any shape, such as a circle, an ellipse, an L-shape, or a T-shape.

[0147] 18A, each bridge 41 may be disposed 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 equal to or greater than 0 and equal to or less than 30 times the width w2 of the steam passage 51. This makes it possible to suppress deformation of the bent portion of the second land portion 33d and to suppress an increase in steam resistance near the bent portion of the second land portion 33d.

[0148] 18B, each bridge 41 may connect one end of the first land 33c to a midpoint of one of the second lands 33d, thereby suppressing deformation of the first land 33c.

[0149] 18(c), each bridge 41 may connect the first land portion 33c to another land portion 33c, 33d adjacent to the first land portion 33c in the width direction or to the frame portion 32. This makes it possible to suppress deformation of the first land portion 33c.

[0150] 18(a) to 18(c), the planar shape of the second land portion 33d may be any shape, such as a curved shape such as an arc, a bent linear shape such as an L-shape, etc. For example, the second land portion 33d may have a curved portion R that is curved in a curved shape in plan view, similar to the example shown in FIGS.

[0151] 19(a)-(c), the bridge 41 is thinned by half-etching from the second body surface 31b side. In this case, the bridge 41 has a top surface 41b located on the second body surface 31b side, a bottom surface 41a located on the first 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. Note that FIG. 19(a) is a plan view of the bridge 41, and FIGS. 19(b) and 19(c) are cross-sectional views taken along line XIX-XIX in FIG. 19(a).

[0152] As shown in FIG. 19( a), the bridge 41 may have a parallelogram shape in a 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 portion 33 may be 20° or more and 70° or less. This reduces steam resistance near the bridge 41 and allows the working steam 2a to flow smoothly near the bridge 41. Note that the entire side surface 41c of the bridge 41 does not necessarily have to be arranged to form an angle θ with the side surface of the land portion 33. For example, a portion of the side surface 41c of the bridge 41 may be arranged to form an angle θ with the side surface of the land portion 33 of 20° or more and 70° or less. In this case, steam resistance near the bridge 41 can also be reduced and allows the working steam 2a to flow smoothly near the bridge 41. Furthermore, the bridge 41 may have a trapezoidal shape in a plan view. In this case, one of the two side surfaces 41c of the bridge 41 may be disposed so as to form an angle θ of 20° or more and 70° or less with respect to the side surface of the land portion 33. In this case as well, steam resistance in the vicinity of the bridge 41 can be reduced, and the working steam 2a can flow smoothly in the vicinity of the bridge 41.

[0153] As shown in FIG. 19B, 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] 19(c), each side surface 41c of the bridge 41 may be inclined with respect to the first body surface 31a and the second body surface 31b. In this case, steam resistance near the bridge 41 is reduced, allowing the working vapor 2a to flow smoothly near the bridge 41. Such inclined side surfaces 41c can be easily fabricated simultaneously with the liquid flow path portion 60 in the etching process. Furthermore, even if the working vapor 2a collides with the bridge 41 and liquefies, the angle between the lower sheet 10 and the side surfaces 41c is obtuse, making it easy to discharge the working liquid 2b along the bridge 41.

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

[0156] 20(a)-(c), the bridge 41 is thinned by half-etching from the second body surface 31b side. In this case, the bridge 41 has a top surface 41b located on the second body surface 31b side, a bottom surface 41a located on the first 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. Note that FIG. 20(a) is a plan view of the bridge 41, and FIGS. 20(b) and 20(c) are cross-sectional views taken along line XX-XX in FIG. 20(a).

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

[0158] 20(b) and 20(c), each side surface 41c of the bridge 41 may be inclined in a curved shape with respect to the first body surface 31a and the second 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 to 10 times the width w2 of the steam passage 51. By making the length L2 of the bridge 41 0.5 times or more the width w2 of the steam passage 51, it is possible to prevent the working steam 2a from stagnating near each side surface 41c of the bridge 41 and to allow the working steam 2a to flow smoothly near the bridge 41. By making the length L2 of the bridge 41 10 times or less the width w2 of the steam passage 51, it is possible to shorten the narrow portion of the steam passage 51 and reduce the pressure loss of the working steam 2a within the steam passage 51.

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

[0160] 21(a) and 21(b), a portion of each side surface 41c of the bridge 41 may be convex (FIG. 21(a)) or concave (FIG. 21(b)) in a plan view. In this case, the flow of the working steam 2a near the bridge 41 can be facilitated. In FIGS. 21(a) and 21(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 thereto. 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. Furthermore, the side surfaces 41c on both the inlet side (negative side in the X direction) and outlet side (positive side in the X direction) of the working steam 2a may also be convex or concave.

[0161] 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 contacts at least one liquid flow path connecting groove 65 located on the outermost side of the land portion 33 in the width direction (Y direction).

[0162] According to this modification, even if the bridges 41 and the upper sheet 20 are not completely bonded by diffusion bonding and a small gap occurs between the bridges 41 and the upper sheet 20, the working fluid 2b that has entered this gap can be allowed to escape through the liquid flow path communication groove 65. As a result, even if the working fluid 2b freezes in a temperature environment below the freezing point of the working fluid 2b, the gap between the bridges 41 and the upper sheet 20 can be prevented from widening due to the frozen working fluid 2b.

[0163] 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 contacts at least one liquid flow path communication groove 65 located at the outermost side in the width direction (Y direction) of the land portion 33. Furthermore, a communication recess 46 that communicates with the liquid flow path communication groove 65 is formed in the top surface 41b of the bridge 41. The communication recess 46 extends across the entire width direction (Y direction) of the steam passage 51.

[0164] According to this modification, the hydraulic fluid 2b that has entered between the bridge 41 and the upper sheet 20 can be released into the liquid flow path communication groove 65 via the communication recess 46. This makes it possible to prevent the gap between the bridge 41 and the upper sheet 20 from widening due to the frozen hydraulic fluid 2b, even if the hydraulic fluid 2b freezes in a temperature environment lower than the freezing point of the hydraulic fluid 2b.

[0165] 24 to 26 , the bridge 41 (shown by the two-dot chain line) is thinned by half-etching from the first main body surface 31a side. In this case, the bridge 41 contacts at least one liquid flow path communication groove 65 located on the outermost side in the width direction of the land portion 33. Furthermore, a plurality of communication recesses 46 that communicate with the liquid flow path communication grooves 65 are formed in 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 one another.

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

[0167] According to this modification, the hydraulic fluid 2b that has entered between the bridge 41 and the upper sheet 20 can be released into the liquid flow path communication groove 65 via the multiple communication recesses 46. This makes it possible to prevent the frozen hydraulic fluid 2b from widening the gap between the bridge 41 and the upper sheet 20, even if the hydraulic fluid 2b freezes in a temperature environment lower than the freezing point of the hydraulic fluid 2b.

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

[0169] As shown in FIG. 24( b), first communication channels 47 may be formed on the top surface 41b of the bridge 41, connecting adjacent communication recesses 46. The first communication channels 47 are arranged between adjacent bridge protrusions 45 in the width direction (Y direction) of the steam passage 51. The bridge protrusions 45 located outermost in the width direction (X direction) of the bridge 41 extend across 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 FIG. 24( b), each first communication channel 47 extends in the X direction and is formed perpendicular to the longitudinal direction of the communication recesses 46. This allows the working fluid 2b that has entered between the bridge 41 and the upper sheet 20 to escape to the liquid channel communication groove 65 via the first communication channels 47 and the communication recesses 46.

[0170] As shown in FIG. 25( a), a second communication flow path 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 flow path 48 is disposed between the bridge protrusions 45 located outermost in the width direction (X direction) of the bridge 41. In FIG. 25( a), the second communication flow path 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. Furthermore, the working fluid 2b condensed in the steam passage 51 can enter from the second communication flow path 48 and be transported to the evaporation region SR via the liquid flow path portion 60.

[0171] As shown in FIG. 25( b), when the bridge 41 connects one end of the first land 33 c and a position midway along the second land 33 d (for example, as shown in FIG. 18( b) described above), multiple communication recesses 46 may be formed on the top surface 41 b of the bridge 41. In this case, the communication recesses 46 communicate with the liquid flow path connecting groove 65 of the second land 33 d. The liquid flow path mainstream groove 61 of the first land 33 c and the communication recesses 46 of the bridge 41 extend continuously. Specifically, the liquid flow path mainstream groove 61 of the first land 33 c and the communication recesses 46 of the bridge 41 are aligned in a plan view. This allows the hydraulic fluid 2 b that has entered between the bridge 41 and the upper sheet 20 to smoothly escape from the communication recesses 46 toward the liquid flow path mainstream groove 61 of the first land 33 c. Furthermore, the working fluid 2b condensed in the vapor passage 51 can be smoothly transported from the communicating recess 46 of the bridge 41 toward the liquid flow path mainstream groove 61 of the first land portion 33c.

[0172] 26 , when the bridge 41 connects one end of the first land 33c to a midpoint of the second land 33d, the first land 33c and the bridge 41 may each have a curved shape in a plan view. In this case, a plurality of communicating recesses 46 are formed on the top surface 41b of the bridge 41. The liquid flow path mainstream groove 61 of the first land 33c and the communicating recesses 46 of the bridge 41 extend continuously. Specifically, the liquid flow path mainstream groove 61 of the first land 33c and the communicating recesses 46 of the bridge 41 are connected by a continuous curve in a plan view. Here, being connected by a continuous curve means that the radius of curvature of the center line of the liquid flow path mainstream groove 61 and the radius of curvature of the center line of the communicating recesses 46 coincide at the connection between the bridge 41 and the first land 33c. This allows the working fluid 2b that has entered between the bridge 41 and the upper sheet 20 to smoothly escape from the communicating recess 46 toward the liquid flow path mainstream groove 61 of the first land portion 33c. In addition, the working fluid 2b that has condensed in the vapor passage 51 can be smoothly transported from the communicating recess 46 of the bridge 41 toward the liquid flow path mainstream groove 61 of the first land portion 33c.

[0173] 27(a) and 27(b) are cross-sectional views of a bridge 41 according to an eleventh modification taken along the width direction (X direction) of the bridge 41. In FIGS. 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 increases from the top surface 41b to 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 to the bottom surface 41a. The side surface 41c of the bridge 41 is connected to the liquid flow path 60 of the land portion 33 connected to the bridge 41.

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

[0175] As shown in FIG. 27A, the top surface 41b of the bridge 41 may be flat, and the communicating recess 46 may not be formed on the top surface 41b of the bridge 41.

[0176] 27(b), a plurality of communication recesses 46 (see the tenth modification) may be formed on the top surface 41b of the bridge 41. In this case, when the working vapor 2a collides with the side surface 41c of the bridge 41 and is liquefied, the working liquid 2b easily flows along the curved side surface 41c into the communication recesses 46 of the bridge 41.

[0177] Second Embodiment Next, a second embodiment will be described with reference to Figures 28 to 38. Figures 28 to 38 are diagrams illustrating the second embodiment. In Figures 28 to 38, the same parts as those in the embodiment shown in Figures 1 to 27 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0178] 28, the vapor chamber 1 according to this embodiment includes 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 a wick sheet 30). The wick sheet 30 is interposed between the lower sheet 10 and the upper sheet 20.

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

[0180] As shown in Figure 32, the liquid flow path section 60 has a plurality of liquid flow path communication grooves 65 that communicate with the liquid flow path main grooves 61. As shown in Figure 31, the liquid flow path main grooves 61 have curved wall surfaces 62. The convex portions 64 are provided in the liquid flow path section 60, and protrude from the liquid flow path main grooves 61 and the liquid flow path communication grooves 65 to abut against the upper sheet 20.

[0181] Figure 33 is an enlarged top view (enlarged view of part XXXIII in Figure 29) showing the frame body part 32 and support part 39 located on the condensation region CR side, and Figure 34 is an enlarged cross-sectional view (cross-sectional view taken along line XXXIV-XXXIV in Figure 33) showing the frame body part 32 and support part 39. Here, in Figure 33, for clarity of the drawing, the liquid flow path mainstream grooves 61 and the convex portion rows 63 are shown enlarged, and the numbers of these liquid flow path mainstream grooves 61 and convex portion rows 63, etc. are different from those in Figures 31 and 32 for convenience.

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

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

[0184] As shown in FIG. 33 , among the multiple protrusions 64 formed on the land portion 33, the protrusions 64 located at the longitudinal end (X direction) 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 disposed on the support portion 39. As described above, multiple (four in FIG. 33 ) protrusion rows 63 are formed on each land portion 33. In this case, all of the multiple protrusion rows 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% or more and 80% or less of the width w6 of the support portion 39. The width w6 of the support portion 39 may be 50 μm or more and 2000 μm or less.

[0185] 34 , on the support portion 39, the convex portion 64 protrudes from the support portion surface 39a toward the second main body surface 31b. In this case, the bottom surface of the liquid flow path mainstream groove 61 formed in the land portion 33 is located on the same plane as the support portion surface 39a. However, this is not limiting, and the bottom surface of the liquid flow path mainstream groove 61 may be offset in the thickness direction (Z direction) of the land portion 33 with respect to the support portion surface 39a.

[0186] In this specification, "the protrusion 64 extends toward the support portion 39" means that the protrusion 64 located at the longitudinal end of the land portion 33 is located further outward in the longitudinal direction of the land portion 33 than a portion of the support portion 39 adjacent to the land portion 33 that is located most inward in the longitudinal direction of the steam passage 51. The "support portion 39 adjacent to the land portion 33" refers to a region of the support portion 39 that is located between the land portion 33 and the land portion 33 adjacent to the land portion 33. In Figure 33 , the protrusion 64 located most toward the frame portion 32 of the land portion 33 (positive side in the X direction) is located closer to the frame portion 32 (positive side in the X direction) than the intersection line 39e, which is the most inner portion of the adjacent support portion 39. The length L3 described above refers to the distance between the convex portion 64 located at the longitudinal end of the land portion 33 and the portion of the support portion 39 located closest to the steam passage 51 in the longitudinal direction (intersection line 39 e), measured in the longitudinal direction of the land portion 33.

[0187] In this embodiment, the protrusions 64 located at the longitudinal ends (positive ends in the X direction) of the land portions 33 on the condensation region CR side (positive side in the X direction) extend toward the support portions 39. This allows the working fluid 2b condensed on the support portions 39 to be returned to the liquid flow path portions 60 and recovered by the capillary force of the liquid flow path portions 60 (see reference numeral 2b in FIG. 33 ). This allows the working fluid 2b to flow smoothly during use of the vapor chamber 1, improving the thermal 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 portions 39 may freeze, preventing damage to the vapor chamber 1. However, this is not limited to this. The protrusions 64 located at the longitudinal ends of the land portions 33 on the evaporation region SR side (negative side in the X direction) may also extend toward the support portions 39.

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

[0189] Next, the operation of this embodiment having the above-described configuration will be described.

[0190] During use of the vapor chamber 1 according to this embodiment, some of the working fluids 2a, 2b reach the support portion 39. The working fluids 2a, 2b that reach the support portion 39 condense to become working liquid 2b, which may accumulate on the support portion 39. In contrast, according to this embodiment, of the multiple convex portions 64 formed on the land portion 33, the convex portions 64 located at the longitudinal ends of the land portion 33 extend toward the support portion 39. As a result, the working fluid 2b that has accumulated on the support portion 39 is recovered into each liquid flow path mainstream groove 61 via the convex portions 64 located at the longitudinal ends of the land portion 33. This promotes the reflux of the working fluids 2a, 2b within the sealed space 3, prevents the flow of the working fluids 2a, 2b from being obstructed, and improves the temperature uniformity of the vapor chamber 1.

[0191] Furthermore, it is conceivable that during use, the electronic device E equipped with the vapor chamber 1 will be placed in an environment with a temperature lower than the freezing point of the working fluid 2b. In response to this, the present embodiment prevents the working fluid 2b from accumulating on the support portion 39. 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 prevented. 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 impediment of heat conduction from the device D is prevented, and performance degradation of the vapor chamber 1 is suppressed.

[0192] Furthermore, according to this embodiment, the support portion inner wall surface 39b of the support portion 39 is inclined so that the first body surface 31a side is located closer to the inside in the longitudinal direction (the negative side in the X direction) of the vapor passage 51 than the second body surface 31b side in the cross section. This allows the working fluids 2a, 2b to flow smoothly from above the support portion 39 toward the inside of the vapor passage 51, and promotes the reflux of the working fluids 2a, 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 so that the first main body surface 31a side is located closer to the inside in the longitudinal direction of the steam passage 51 (the negative side in the X direction) than the second main body surface 31b side in the cross section. This makes it difficult for the working fluid 2b to accumulate in the corners between the frame portion 32 and the support portion 39, and allows the working fluid 2b to be smoothly recovered toward the liquid passage portion 60.

[0194] (Modifications) 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 portions of the wick sheet 30 according to the modifications. In Figures 35 to 38, the same parts as those shown in Figures 28 to 34 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0195] 35 , at the longitudinal ends (negative ends in the X direction) of the steam passage 51, the intersection lines 39e of the support portions 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 width direction end of the steam passage 51, the intersection lines 39e of the support portions 39 are curved inward in the longitudinal direction of the steam passage 51 (negative side in the X direction) as they move from the inside to the outside in the width direction (Y direction) of the steam passage 51 in plan view. The intersection lines 39e of the support portions 39 may be arc-shaped or elliptical-shaped in plan view, or may be a line segment with curves connected to both sides thereof in plan view.

[0196] According to this modification, the working fluid 2b present on the support portion surface 39a and the support portion inner wall surface 39b of the support portion 39 can be made to flow into the liquid flow path portion 60 from the side surface (first wall surface 53a and second wall surface 54a) of the land portion 33 (see reference symbol 2b in FIG. 35 ). As a result, the working fluid 2b accumulated on the support portion 39 is efficiently recovered into the liquid flow path portion 60 via the side surface of the land portion 33. This further promotes the reflux of the working fluids 2a, 2b within the sealed space 3.

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

[0198] 36(a), for example, 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). This allows capillary force to act on the long protrusion 64A, preventing the working fluid 2b from adhering to the periphery of the protrusion 64A and allowing the working fluid 2b to be efficiently returned to the liquid flow path portion 60. This prevents the vapor chamber 1 from expanding in the area of ​​the support portion 39 during a thermal cycle test in which heating and cooling are repeated.

[0199] 36( a), the length L4 of the protrusions 64A located at the longitudinal ends of some of the protrusion rows 63 is longer than the length L1 of the other protrusions 64. On the other hand, the length of the protrusions 64 located at the longitudinal ends of some of the other protrusion rows 63 is the same as the length L1 of the other protrusions 64. However, this is not limiting, and the length L4 of the protrusions 64A located at the longitudinal ends of all of the protrusion rows 63 may be longer than the length L1 of the other protrusions 64.

[0200] 36(b), the lengths L5 and L6 of the protrusions 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 protrusions 64 (L5<L1, L6<L1). This allows the liquid flow path communication groove 65 to be located near the support portion 39, so that the hydraulic fluid 2b remaining on the support portion 39 can be efficiently taken into the liquid flow path portion 60. Note that the length L6 of the protrusion 64C adjacent in the longitudinal direction (X direction) to the protrusions 64B and 64C located at the longitudinal ends of the land portion 33 may also be shorter than the length L1 of the other protrusions 64.

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

[0202] 37(a) to 37(d), among the multiple (four in this case) protrusion rows 63, protrusions 64E (64) located at the longitudinal ends of some of the protrusion rows 63 may extend toward the support portion 39. Protrusions 64F (64) located at the longitudinal ends of the other protrusion rows 63 may not extend toward the support portion 39.

[0203] 37( a), a row of protrusions 63 including a protrusion 64E extending toward the support portion 39 and a row of protrusions 63 including a protrusion 64F that does not extend toward the support portion 39 may be alternately provided in the width direction (Y direction) of the land portion 33. Note that "the protrusion 64F does not extend toward the support portion 39" means that the protrusion 64F overlaps with a portion of the adjacent support portion 39 that is located most inward in the longitudinal direction of the steam passage 51, or is located more inward in the longitudinal direction of the land portion 33 than that portion.

[0204] 37(b), the convex portion 64E of the convex portion row 63 located on the inner side of the land portion 33 in the width direction (Y direction) may extend toward the support portion 39. The convex portions 64F of the convex portion row 63 located on both ends of the land portion 33 in the width direction may not extend toward the support portion 39.

[0205] 37(c), the convex portions 64E of the convex portion rows 63 located at both ends of the land portion 33 in the width direction (Y direction) may extend toward the support portion 39. The convex portion 64F of the convex portion rows 63 located on the inner side of the land portion 33 in the width direction may not extend toward the support portion 39.

[0206] 37(d), the convex portion 64E of the convex portion row 63 located at one end of the land portion 33 in the width direction (Y direction) may extend toward the support portion 39. The convex portion 64F of the convex portion row 63 located at the other end of the land portion 33 in the width direction and the convex portion 64F of the convex portion row 63 located on the inner side of the land portion 33 in the width direction may not extend toward the support portion 39.

[0207] According to this modification, the width of the inlet through which the working fluid 2b flows into the liquid flow path main groove 61 can be increased (see, for example, the double-headed arrow in FIG. 37(a) ). This allows the working fluid 2b remaining on the support portion 39 to be efficiently taken into the liquid flow path portion 60.

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

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

[0210] According to this modification, the working fluid 2b remaining on the support portion 39 at one widthwise end (first end point 39g) of the land portion 33 can be efficiently taken into the liquid flow path portion 60. Meanwhile, at the other widthwise end (second end point 39h) of the land portion 33, the volume of the vapor passage 51 is wider, so the pressure of the working vapor 2a can be reduced in this region. In particular, when the support portion 39 is located near the evaporation region SR, a sudden increase in pressure in the space around the support portion 39 due to the working vapor 2a generated in the evaporation region SR can be suppressed.

[0211] In this embodiment, unlike the first embodiment, a bridge 41 is not provided within the steam flow path section 50, but this is not limited to this, and a bridge 41 may be provided within 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 are diagrams showing the third embodiment. The third embodiment shown in Figures 39 to 44 differs from the second embodiment mainly in that the convex portions 64 located at the longitudinal ends of the lands 33 are arranged spaced apart from the support portions 39. In Figures 39 to 44, the same parts as those shown in Figures 1 to 38 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0213] As shown in Figures 39 and 40, the wick sheet 30 according to this embodiment includes 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. A steam passage 51 through which the working steam 2a passes is formed between the plurality of land portions 33. A liquid flow path portion 60, communicating with the steam passage 51 and through which the working fluid 2b passes, is formed on the second main body surface 31b side of at least one land portion 33. The liquid flow path portion 60 has a plurality of liquid flow path mainstream grooves 61 through which the working fluid 2b passes and which are arranged parallel to each other. A convex portion row 63 is provided between adjacent liquid flow path mainstream grooves 61. Each convex portion row 63 has a plurality of convex portions 64. The convex portions 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 part XL in Figure 39) showing the frame body part 32 and support part 39 located on the evaporation region SR side, and Figure 41 is an enlarged cross-sectional view (cross-sectional view taken along line XLI-XLI in Figure 40) showing the frame body part 32 and support part 39. Here, in Figure 40, for clarity of the drawing, the liquid flow path mainstream grooves 61 and the convex portion rows 63 are shown enlarged, and the number of these liquid flow path mainstream grooves 61 and convex portion rows 63 may differ from other figures for convenience. Also, in Figure 40, the injection flow path 37 and the like are not shown.

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

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

[0217] As shown in FIG. 40 , among the multiple protrusions 64 formed on the land portion 33, the protrusions 64 located at the longitudinal (X-direction) ends of the land portion 33 are spaced apart from the support portion 39 on the longitudinal inward side of the land portion 33 (the positive side in the X-direction). That is, the protrusions 64 located at the longitudinal ends of the land portion 33 are not located on the support portion 39 but are spaced apart from the support portion 39. As described above, multiple protrusion rows 63 (four rows in FIG. 40 ) are formed on each land portion 33. In this case, all of the multiple protrusion rows 63 formed on the land portion 33 are spaced apart from the support portion 39 by the same length L7. This length L7 of space 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] 41 , the convex portion 64 protrudes from the liquid flow path mainstream groove 61 toward the second main body surface 31b at a position away from the support portion 39. In this case, the bottom surface of the liquid flow path mainstream groove 61 formed in the land portion 33 is located on the same plane as the support portion surface 39a. However, this is not limiting, and the bottom surface of the liquid flow path mainstream groove 61 may be offset in the thickness direction (Z direction) of the land portion 33 with respect to the support portion surface 39a.

[0219] In this specification, "the protrusion 64 is disposed away from the support portion 39" means that the protrusion 64 located at the longitudinal end of the land portion 33 is located more inward in the longitudinal direction of the land portion 33 than a portion of the support portion 39 adjacent to the land portion 33 that is located most inward in the longitudinal direction of the steam passage 51. The "support portion 39 adjacent to the land portion 33" refers to a region of the support portion 39 that is located between the land portion 33 and the land portion 33 adjacent to the land portion 33. In Figure 40, the protrusion 64 located most toward the frame portion 32 of the land portion 33 (negative side in the X direction) is located more inward in the longitudinal direction of the land portion 33 than the intersection line 39e, which is the most inner portion of the adjacent support portion 39. The length L7 mentioned above refers to the distance between the convex portion 64 located at the longitudinal end of the land portion 33 and the portion of the support portion 39 located closest to the steam passage 51 in the longitudinal direction (intersection line 39 e), measured along the longitudinal direction of the land portion 33.

[0220] As described above, in this embodiment, the convex portion 64 located at the longitudinal end (negative end in the X direction) of the land portion 33 on the evaporation region SR side (negative side in the X direction) is spaced apart from the support portion 39. In other words, the steam passage 51 located between adjacent lands 33 extends to the support portion 39 side. This expands the volume of the steam passage 51 near the longitudinal end of the land portion 33 (reference symbol AR in FIG. 40 ), thereby reducing 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, a sudden increase in pressure in the space around the support portion 39 due to the working steam 2a generated in the evaporation region SR can be suppressed. Furthermore, extending the steam passage 51 to the support portion 39 side promotes evaporation of the working steam 2a from the distal end of the land portion 33. This promotes the circulation of the working fluids 2a and 2b within the sealed space 3, and the flow of the working fluids 2a and 2b is not obstructed, thereby improving the temperature uniformity of the vapor chamber 1.

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

[0222] Next, the operation of this embodiment having the above-described configuration will be described.

[0223] During use of the vapor chamber 1 according to this embodiment, the working fluid 2b on the land portion 33 near the evaporation region SR evaporates due to heat from the device D. As the working fluid 2b evaporates, it transforms into working vapor 2a, rapidly expanding in volume. In contrast, according to this embodiment, the convex portions 64 located at the longitudinal ends of the land portion 33 are spaced apart from the support portions 39. This allows the working vapor 2a generated on the land portion 33 to quickly flow into the vapor passage 51 adjacent to the land portion 33 in the width direction (Y direction) without being obstructed by the convex portions 64 (see reference numeral 2a in FIG. 40 ). Furthermore, between adjacent lands 33, there exists a wide region AR of the vapor passage 51. As a result, the working vapor 2a generated on the land portion 33 quickly escapes into the region AR of the vapor passage 51, preventing a sudden increase in pressure within the space above the land portion 33.

[0224] Furthermore, by suppressing the pressure increase in the space above the land portion 33, deformation of the upper sheet 20 due to the force generated when the working fluid 2b evaporates on the land portion 33 is suppressed. This suppresses 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 suppresses the formation of a gap between the second upper sheet surface 20b and the device D. As a result, it is possible to suppress the obstruction of heat conduction from the device D, and suppress a decrease in performance of the vapor chamber 1.

[0225] Furthermore, according to this embodiment, the support portion inner wall surface 39b of the support portion 39 is curved so that the first body surface 31a side is located closer to the inside in the longitudinal direction (the positive side in the X direction) of the vapor passage 51 than the second body surface 31b side in the cross section. This allows the working fluids 2a, 2b to flow smoothly from above the support portion 39 toward the inside of the vapor passage 51, and promotes the reflux of the working fluids 2a, 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 so that the first main body surface 31a side is positioned closer to the inside in the longitudinal direction (the positive side in the X direction) of the vapor passage 51 than the second main body surface 31b side in the cross section. This allows the working fluids 2a, 2b to flow smoothly from the frame portion 32 side through the support portion 39 toward the inside of the vapor passage 51, and promotes the reflux of the working fluids 2a, 2b within the vapor chamber 1.

[0227] (Modifications) 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 portions of the wick sheet 30 according to modifications. In Figures 42 to 44, the same parts as those shown in Figures 40 and 41 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0228] 42 , at the longitudinal ends (negative ends in the X direction) of the steam passage 51, the intersection lines 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 width direction end of the steam passage 51, the intersection lines 39e of the support parts 39 are curved inward in the longitudinal direction of the steam passage 51 (positive side in the X direction) as they move from the inside to the outside in the width direction (Y direction) of the steam passage 51 in plan view. The intersection lines 39e of the support parts 39 may be arc-shaped or elliptical-shaped in plan view, or may have a shape formed by connecting a line segment with curves on both sides in plan view.

[0229] According to this modification, the working steam 2a can be smoothly flowed between the top of the support portion 39 and the steam passage 51 via the curved portions located at both ends in the width direction of the support portion inner wall surface 39b of the support portion 39 (see reference symbol 2a in FIG. 42 ). 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 inner wall surface 39b. As a result, the action of the working fluids 2a, 2b circulating within the sealed space 3 can be further promoted.

[0230] (Second Modification) As shown in FIGS. 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 FIG. 43( a), the longitudinal ends (negative end in the X direction) of the steam passages 51 may extend to the inner wall surface 32a of the frame body 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 (negative end in the X direction) of a land portion 33 and connects the corresponding land portion 33 and frame body 32 to each other. The steam passages 51 are formed between adjacent connecting portions 39j.

[0232] This further increases the volume of the vapor passage 51 near the longitudinal end of the land portion 33 (symbol AR in FIG. 43( a)), thereby reducing 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 prevent a sudden increase in pressure in the space around the support portion 39 due to the working steam 2a generated in the evaporation region SR. Furthermore, extending the vapor passage 51 to the support portion 39 side promotes evaporation of the working steam 2a from the end side of the land portion 33.

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

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

[0235] 44(a), for example, 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). This allows capillary force to act on the long protrusion 64A, preventing the working fluid 2b from adhering to the periphery of the protrusion 64A and allowing the working fluid 2b to be efficiently returned to the liquid flow path portion 60. This prevents the vapor chamber 1 from expanding in the area of ​​the support portion 39 during a thermal cycle test in which heating and cooling are repeated.

[0236] 44( a), the length L4 of the protrusions 64A located at the longitudinal ends of some of the protrusion rows 63 is longer than the length L1 of the other protrusions 64. On the other hand, the length of the protrusions 64 located at the longitudinal ends of some of the other protrusion rows 63 is the same as the length L1 of the other protrusions 64. However, this is not limiting, and the length L4 of the protrusions 64A located at the longitudinal ends of all of the protrusion rows 63 may be longer than the length L1 of the other protrusions 64.

[0237] 44(b), the lengths L5 and 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). This increases the areas of the liquid flow path main grooves 61 and the liquid flow path connecting grooves 65 of the liquid flow path portion 60 near the support portion 39, thereby facilitating evaporation of the working fluid 2b on the land portion 33.

[0238] 44(b), the lengths L5 and L6 of the protrusions 64B and 64C located at the longitudinal ends of all of the protrusion rows 63 are shorter than the length L1 of the other protrusions 64. However, this is not limiting, and the length L1 of the protrusions 64 located at the longitudinal ends of some of the protrusion rows 63 may be the same as the length L1 of the other protrusions 64.

[0239] In this embodiment, unlike the first embodiment, a bridge 41 is not provided within the steam flow path section 50, but this is not limited to this, and a bridge 41 may be provided within the steam flow path section 50.

[0240] The present disclosure is not limited to the above-described embodiments and modifications, and the components can be modified and embodied in practice without departing from the spirit of the present disclosure. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiments and modifications. Some components may be omitted from all the components shown in the embodiments and modifications.

Claims

1. A wick sheet for a vapor chamber, comprising: A first body surface; and a second body surface located opposite the first body surface; A frame portion, A plurality of land portions are provided in the frame portion and spaced apart from each other, A steam passage is formed between the plurality of land portions, the steam passage extending from the first body surface to the second body surface and through which the steam of the working fluid passes, a liquid flow path portion through which the liquid working fluid passes, the liquid flow path portion communicating with the vapor path, is formed on the second main body surface side of at least one of the land portions; A bridge is provided to connect the land portion and the frame portion or to connect the land portions to each other, The bridge is thinned from at least one of the first body surface side and the second body surface side, the liquid flow path portion has a plurality of liquid flow path mainstream grooves through which the liquid working fluid passes, and a plurality of liquid flow path communication grooves communicating with the liquid flow path mainstream grooves, the bridge contacts the liquid flow path communication groove located at the outermost position in a width direction of the land portion, The bridge has a top surface located on the second main body surface side, and a communication recess communicating with the liquid flow path communication groove is formed in the top surface. A wick sheet.

2. The wick sheet according to claim 1 , wherein a plurality of the communicating recesses are formed on the top surface of the bridge, and a first communicating flow passage is formed on the top surface, connecting adjacent ones of the communicating recesses.

3. The wick sheet according to claim 1 or 2, wherein a second communication flow passage that connects the communication recess and the steam passage is formed at an outermost position in the width direction of the bridge.

4. 4. A wick sheet as described in any one of claims 1 to 3, wherein 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 a midpoint of the second land portion, and the liquid flow path main groove of the first land portion and the communicating recess of the bridge extend continuously.

5. The wick sheet according to any one of claims 1 to 4, wherein the bridge has a top surface located on the second body surface side and a bottom surface located on the first body surface side, and the width of the bridge gradually increases from the top surface to the bottom surface.

6. A vapor chamber containing a working fluid, A first sheet; A second sheet; A vapor chamber comprising: a wick sheet according to claim 1 interposed between the first sheet and the second sheet.

7. Housing and a device contained within the housing; and An electronic device comprising: the vapor chamber of claim 6 in thermal contact with the device.