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

Abstract

This wick sheet (30) for a vapor chamber (1) comprises a first body surface (31a), a second body surface (31b), a frame body part (32), and a plurality of land parts (33). A steam passage (51) is formed which passes through the first body surface (31a) and the second body surface (31b) and through which steam (2a) of a working fluid passes, and a fluid flow passage part (60), which communicates with the steam passage (51) and through which a liquid working fluid (2b) passes, is formed on the second body surface (31b) side of the land part (33). An extension direction end of a steam passage (51B) is in contact with at least one land part (33A), and a first body surface-side flow passage (70) which communicates with the steam passage (51B) is formed on the first body surface (31a) side of the land part (33A) and in a connection region (MR) which is in contact with the extension direction end of the steam passage (51B).

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] Japanese Patent Application Laid-Open No. 2016-017702

[0005] The present embodiment provides a vapor chamber, a wick sheet for a vapor chamber, and an electronic device that can distribute working vapor over a wide area within the vapor chamber. The present embodiment also provides a vapor chamber, a wick sheet for a vapor chamber, and an electronic device that can distribute heat from a heat source uniformly within the surface of the vapor chamber.

[0006] 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 provided within the frame body portion and spaced apart from one another. A steam passage is formed between the frame body portion and the land portion, or between the plurality of land portions, penetrating the first body surface and the second body surface and through which vapor of the working fluid passes. A liquid flow path portion is formed on the second body surface side of at least one of the land portions, communicating with the steam passage and through which the liquid working fluid passes. An extension direction end of the steam passage is in contact with at least one land portion of the plurality of land portions, and a first body surface side flow path communicating with the steam passage is formed in a connection region on the first body surface side of the land portion where the extension direction ends of the steam passage are in contact.

[0007] 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 wick sheet of FIG. 3. FIG. 5 is a bottom view of the wick sheet of FIG. 3. FIG. 6 is a cross-sectional view of the vapor chamber of FIG. 2 taken along line VI-VI. FIG. 7 is a partially enlarged top view illustrating the liquid flow path portion of FIG. 4. FIG. 8 is a partially enlarged bottom view illustrating the first main body surface-side flow path of FIG. 5. FIG. 9 is an enlarged bottom view (enlarged view of portion VIII of FIG. 5) illustrating the periphery of the connection region of the wick sheet. FIGS. 10(a)-(c) are diagrams illustrating a method for manufacturing a vapor chamber according to the first embodiment. FIG. 11 is an enlarged bottom view illustrating the periphery of the connection region of a wick sheet according to a first modified example of the first embodiment. FIG. 12 is an enlarged bottom view illustrating the periphery of the connection region of a wick sheet according to a second modified example of the first embodiment. FIG. 13 is an enlarged bottom view showing the periphery of the connection region of a wick sheet according to a third modified example of the first embodiment. FIG. 14 is an enlarged bottom view showing the periphery of the connection region of a wick sheet according to a fourth modified example of the first embodiment. FIG. 15 is an enlarged bottom view showing the periphery of the connection region of a wick sheet according to a fifth modified example of the first embodiment. FIGS. 16(a) and 16(b) are enlarged bottom views showing the periphery of the connection region of a wick sheet according to a fifth modified example of the first embodiment. FIGS. 17(a) and 17(b) are enlarged bottom views showing the periphery of the connection region of a wick sheet according to a fifth modified example of the first embodiment. FIGS. 18(a) to 18(c) are cross-sectional views (cross-sectional views taken along line XVIII-XVIII in FIGS. 15 to 17) of the connection region of a wick sheet according to a fifth modified example of the first embodiment. FIG. 19 is a schematic perspective view illustrating an electronic device according to a second embodiment. FIG. 20 is a top view showing a vapor chamber according to the second embodiment. FIG. 21 is a cross-sectional view taken along line XXI-XXI of the vapor chamber of FIG. 20. Fig. 22 is a top view of a wick sheet according to a second embodiment. Fig. 23 is a bottom view of a wick sheet according to the second embodiment. Fig. 24 is a partially enlarged top view of the liquid flow path portion shown in Fig. 22. Figs. 25(a) and (b) are schematic top views showing the wick sheet.FIGS. 26(a)-(c) are top views showing the flow of the working fluid within the wick sheet. FIG. 27 is a top view showing a wick sheet according to a first modified example of the second embodiment. FIGS. 28(a) and 28(b) are top views showing a wick sheet according to a second modified example of the second embodiment. FIGS. 29(a) and 29(b) are top views showing a wick sheet according to a third modified example of the second embodiment. FIGS. 30(a)-30(c) are top views showing a wick sheet according to a fourth modified example of the second embodiment. FIGS. 31(a) and 31(b) are top views showing a wick sheet according to a fifth modified example of the second embodiment. FIG. 32 is a top view showing a wick sheet according to a sixth modified example of the second embodiment. FIG. 33 is a top view showing a wick sheet according to a seventh modified example of the second embodiment. FIG. 34 is a top view showing a wick sheet according to an eighth modified example of the second embodiment. FIG. 35 is a top view showing a wick sheet according to a ninth modified example of the second embodiment. 36(a) to 36(c) are cross-sectional views showing a vapor chamber according to a modification of the second embodiment.

[0008] A first aspect of the present disclosure is a wick sheet for a vapor chamber, comprising: a first body surface; a second body surface located opposite the first body surface; a frame body portion; and a plurality of land portions provided within the frame body portion and spaced apart from one another; a vapor passage penetrating the first body surface and the second body surface and through which vapor of a working fluid passes is formed between the frame body portion and the land portions or between the plurality of land portions; a liquid flow path portion communicating with the vapor passage and through which liquid working fluid passes is formed on the second body surface side of at least one of the land portions; an extension direction end of the vapor passage abuts on at least one of the plurality of land portions; and a first body surface side flow path communicating with the vapor passage is formed in a connection region on the first body surface side of the land portion where the extension direction ends of the vapor passage abut.

[0009] In a second aspect of the present disclosure, in the wick sheet of the first aspect described above, another steam passage may be present on the opposite side of the connection region to the side where the end of the steam passage in the extension direction contacts.

[0010] A third aspect of the present disclosure is a wick sheet according to the first or second aspect described above, wherein an evaporation area in which a heat source is arranged is present on the wick sheet, and the first main body surface side flow path may be formed continuously along the land portion to the evaporation area.

[0011] A fourth aspect of the present disclosure is a wick sheet according to any one of the first to third aspects described above, wherein the first main body surface side flow path may also be formed in another land portion extending along the steam passage.

[0012] A fifth aspect of the present disclosure is a wick sheet according to any one of the first to fourth aspects described above, wherein the land portion and the steam passage may intersect at a non-right angle in a plan view in a connection region where the extension direction ends of the steam passage meet.

[0013] A sixth aspect of the present disclosure is the wick sheet according to any one of the first to fifth aspects, wherein the connection region may be located in a curved portion of the land portion.

[0014] A seventh aspect of the present disclosure is the wick sheet of any one of the first to sixth aspects described above, wherein the steam passage has a shape in which the width gradually narrows toward the end in the extension direction.

[0015] An eighth aspect of the present disclosure is a wick sheet according to any one of the first to seventh aspects described above, wherein at least two of the plurality of land portions are joined together, and an end portion in the extension direction of the steam passage is in contact with the land portion at this joined portion.

[0016] A ninth aspect of the present disclosure is a wick sheet according to any one of the first to fourth aspects described above, wherein the steam passage and the land portion may be perpendicular to each other in a plan view at a position where an end portion in an extension direction of the steam passage contacts the land portion.

[0017] A tenth aspect of the present disclosure is a vapor chamber containing a working fluid, the vapor chamber comprising a first sheet, a second sheet, and a wick sheet of any one of the first to ninth aspects described above, interposed between the first sheet and the second sheet.

[0018] An eleventh aspect of the present disclosure is an electronic device comprising a housing, a device housed in the housing, and the vapor chamber of the tenth aspect described above in thermal contact with the device.

[0019] According to the first to eleventh aspects of the present disclosure, the working vapor can be distributed over a wide area within the vapor chamber.

[0020] A twelfth aspect of the present disclosure is a wick sheet for a vapor chamber, comprising a vapor passage through which vapor of a working fluid passes, and a liquid flow path portion communicating with the vapor passage and through which the liquid working fluid passes, wherein a first heat source region in which a first heat source is disposed and a second heat source region in which a second heat source is disposed are disposed on the wick sheet, and the first heat source region and the second heat source region are connected to each other by at least one connecting vapor passage having a length not greater than twice the center-to-center distance between the first heat source region and the second heat source region, or are connected to each other by at least one connecting liquid flow path having a length not greater than twice the center-to-center distance between the first heat source region and the second heat source region.

[0021] A thirteenth aspect of the present disclosure is a wick sheet for a vapor chamber, in the twelfth aspect described above, comprising a vapor passage through which vapor of a working fluid passes, and a liquid flow path portion communicating with the vapor passage and through which the liquid working fluid passes, wherein a first heat source region in which a first heat source is disposed and a second heat source region in which a second heat source is disposed are disposed on the wick sheet, and the first heat source region and the second heat source region are connected to each other by at least one connecting vapor passage and at least one connecting liquid flow path.

[0022] A fourteenth aspect of the present disclosure is a wick sheet according to the twelfth or thirteenth aspect described above, wherein the steam passage may include a single steam passage connected to either the first heat source region or the second heat source region, but not connected to the other.

[0023] A fifteenth aspect of the present disclosure is a wick sheet according to any one of the twelfth to fourteenth aspects described above, wherein the first heat source region and the second heat source region are connected to each other by at least one connecting steam passage, and the steam passage may include a branch steam passage connected midway through the connecting steam passage.

[0024] A sixteenth aspect of the present disclosure is a wick sheet according to any one of the twelfth to fifteenth aspects described above, wherein the liquid flow path portion may include a single liquid flow path that is connected to either the first heat source region or the second heat source region and is not connected to the other.

[0025] A seventeenth aspect of the present disclosure is a wick sheet according to any one of the twelfth to sixteenth aspects described above, wherein the first heat source region and the second heat source region are connected to each other by at least one connecting liquid flow path, and the liquid flow path portion may include a branch liquid flow path connected midway through the connecting liquid flow path.

[0026] An 18th aspect of the present disclosure is a wick sheet according to the 17th aspect described above, wherein the branched liquid flow path is curved at the connection with the connecting liquid flow path, and the connection between the branched liquid flow path and the connecting liquid flow path may have a connection recess in which no liquid flow path exists.

[0027] A 19th aspect of the present disclosure is a wick sheet according to the 17th aspect described above, wherein the branched liquid flow path is curved at the connection with the connecting liquid flow path, and a connecting liquid flow path may be present at the connection between the branched liquid flow path and the connecting liquid flow path.

[0028] A twentieth aspect of the present disclosure is a wick sheet according to any one of the twelfth to nineteenth aspects described above, wherein a third heat source region in which a third heat source is disposed is disposed on the wick sheet, and the third heat source region and the first heat source region or the second heat source region may be connected to each other by at least one of the connecting steam passages or at least one of the connecting liquid flow paths.

[0029] A 21st aspect of the present disclosure is a wick sheet according to any one of the 12th to 20th aspects described above, wherein a third heat source region in which a third heat source is disposed is disposed on the wick sheet, the second heat source region and the third heat source region are connected to each other by at least one of the connecting steam passages or at least one of the connecting liquid flow paths, and the third heat source region and the first heat source region may be connected to each other by at least one of the connecting steam passages or at least one of the connecting liquid flow paths.

[0030] A 22nd aspect of the present disclosure is a wick sheet according to any one of the 12th to 21st aspects described above, wherein the steam passage includes at least two branch steam passages connected midway through the connecting steam passage, and one of the at least two branch steam passages may extend toward the outside in the surface direction of the wick sheet, and the other branch steam passage may extend toward the inside in the surface direction of the wick sheet.

[0031] A 23rd aspect of the present disclosure is a vapor chamber containing a working fluid, the vapor chamber comprising at least one sheet and a wick sheet according to any one of the 12th to 22nd aspects described above laminated on the sheet.

[0032] A 24th aspect of the present disclosure is a vapor chamber in which a working fluid is sealed, comprising a vapor passage through which vapor of the working fluid passes, and a liquid flow path portion communicating with the vapor passage and through which the liquid working fluid passes, wherein a first heat source region in which a first heat source is disposed and a second heat source region in which a second heat source is disposed are disposed, and the first heat source region and the second heat source region are connected to each other by at least one connecting vapor passage having a length not greater than twice the center-to-center distance between the first heat source region and the second heat source region, or are connected to each other by at least one connecting liquid flow path having a length not greater than twice the center-to-center distance between the first heat source region and the second heat source region.

[0033] A 25th aspect of the present disclosure is a vapor chamber in which a working fluid is sealed, comprising a vapor passage through which vapor of the working fluid passes, and a liquid flow path portion communicating with the vapor passage and through which the liquid working fluid passes, wherein a first heat source region in which a first heat source is disposed and a second heat source region in which a second heat source is disposed are disposed, and the first heat source region and the second heat source region are connected to each other by at least one connecting vapor passage and at least one connecting liquid flow path.

[0034] A 26th aspect of the present disclosure comprises a housing, the first heat source and the second heat source contained within the housing, and a vapor chamber according to any one of the 23rd to 25th aspects described above, in thermal contact with the first heat source and the second heat source.

[0035] According to the twelfth to twenty-sixth aspects of the present disclosure, heat from the heat source can be distributed uniformly within the surface of the vapor chamber.

[0036] First Embodiment Hereinafter, a first embodiment will be described with reference to the drawings. 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.

[0037] 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 these parts may differ from each other within the range within which the functions can be expected. In the drawings, boundaries 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 is arbitrary within the range within which the desired joining performance can be expected.

[0038] 1 to 9 , 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 source (heat-generating element) 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), power semiconductors, and the like.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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 will be described in which the planar shape of the vapor chamber 1 is a rectangle with the X direction (described later) as the longitudinal direction. In this case, as shown in FIG. 2 , 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.

[0043] 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.

[0044] The evaporation region SR is an area that overlaps the device D, which is a heat source, 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 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 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.

[0045] The condensation region CR is a region that does not overlap with the device D, which is a heat source, 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.

[0046] 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.

[0047] 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 entire first lower sheet surface 10a may be covered with the housing member Ha.

[0048] 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.

[0049] 3, the wick sheet 30 includes a vapor flow path section 50, a liquid flow path section 60 disposed adjacent to the vapor flow path section 50, and a first main body surface side flow path 70 disposed on the opposite side of the liquid flow path section 60 in the thickness direction of the wick sheet 30. 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.

[0050] 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.

[0051] As shown in FIGS. 3 to 5 , 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.

[0052] In this embodiment, the land portion 33 may be elongated in a planar view. The planar shape of the land portion 33 may be any shape, such as an elongated rectangular shape, an arc, a curved shape such as a U-shape or an S-shape, or a bent linear shape such as a V-shape or an L-shape. In FIGS. 4 and 5 , the multiple lands 33 include those (second land portion 33B, third land portion 33C) extending linearly in the X direction (first direction) in a planar view, and those (first land portion 33A) consisting of a linear portion and a substantially S-shaped curved portion. Furthermore, each land portion 33 may be spaced apart from other lands 33 in the width direction of the land portion 33. 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 of the land portion 33 (see FIG. 3 ) 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 a direction (width direction) perpendicular to the extension direction of the land portion 33, and means the dimension at the thickest position of the land portion 33 (for example, the position where the protrusion portion 55 described later is present).

[0053] 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.

[0054] As shown in Figures 4 and 5, the multiple lands 33 include a first land 33A, a second land 33B, and a third land 33C. Each of the first land 33A, the second land 33B, and the third land 33C has a liquid flow path 60 through which the hydraulic fluid 2b passes. However, any of the first land 33A, the second land 33B, and the third land 33C may not have the liquid flow path 60. The first land 33A, the second land 33B, and the third land 33C may each extend linearly or may have any shape, such as an arc, an S-shaped curve, a V-shaped curve, an L-shaped curve, or the like. In this specification, the first land 33A, the second land 33B, and the third land 33C are collectively referred to simply as the land 33.

[0055] The first land portion 33A extends from the evaporation region SR side, and is connected to the second land portion 33B or the third land portion 33C midway along its extension direction. One end of the first land portion 33A in its extension direction (the negative X-direction side) overlaps with the evaporation region SR. The other end of the first land portion 33A in its extension direction (the positive X-direction side) is preferably located in the condensation region CR, which is spaced outward from the evaporation region SR in the planar direction. For example, it may terminate at a support portion 39 (described later). In this case, one or more second lands 33B and / or one or more third lands 33C are connected to the first land portion 33A. In this embodiment, the first land portion 33A has a substantially S-shaped curved portion midway and extends in the X-direction as a whole in a planar view. Furthermore, in this embodiment, a plurality (two) of first lands 33A are provided, and these first lands 33A are arranged substantially parallel to each other. The other end of the first land portion 33A in the extension direction may be connected to another first land portion 33A.

[0056] The second land portion 33B extends from the evaporation region SR side and is connected to the first land portion 33A. That is, one end side of the second land portion 33B in the extension direction (the negative X-direction side) overlaps with the evaporation region SR, and the other end side of the second land portion 33B in the extension direction (the positive X-direction side) is connected to the first land portion 33A. In this embodiment, the second land portion 33B extends linearly along the X-direction in a plan view. However, the second land portion 33B may have any shape, such as a curved shape such as an arc or an S-shape, or a bent linear shape such as a V-shape or an L-shape. In this embodiment, a plurality of second lands 33B (three in number) are provided, and these second lands 33B are arranged parallel to one another.

[0057] The third land portion 33C is located outside the evaporation region SR and is connected to the first land portion 33A. That is, one end of the third land portion 33C in the extension direction (the negative X-direction side) is connected to the first land portion 33A. The other end of the third land portion 33C in the extension direction (the positive X-direction side) is preferably located in the condensation region CR, which is located away from the evaporation region SR toward the outside in the planar direction, and may terminate at, for example, a support portion 39 (described later). In this embodiment, the third land portion 33C extends linearly along the X-direction in a planar view. However, the third land portion 33C may have any shape, such as a curved line (e.g., an arc, an S-shape, or a V- or L-shape). In this embodiment, a plurality (three) of third lands 33C are provided, and these third lands 33C are arranged parallel to one another.

[0058] 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.

[0059] As shown in Figures 4 and 5, 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 can be any shape, such as an elongated rectangular shape, 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 land sections 33.

[0060] 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. The steam passage 51 may also be referred to as a through space.

[0061] 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. 3 , 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 of the protrusion 55. The width w2 of the steam passage 51 (see FIG. 3 ) 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 a direction (width direction) perpendicular to the extension direction of the steam passage 51 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).

[0062] 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. 3), the distance t5 may be 5% or more, 10% or more, or 20% or more of the thickness t4 (see FIG. 3) 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).

[0063] In addition, in this embodiment, the cross-sectional shape of the steam passage 51 is defined by the protrusion 55 formed to protrude inward of the steam passage 51, 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.

[0064] 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.

[0065] 4 and 5 , the multiple steam passages 51 include a first steam passage 51A, a second steam passage 51B, and a third steam passage 51C. The first steam passage 51A, the second steam passage 51B, and the third steam passage 51C are all flow paths through which the working steam 2a passes, and are formed between the multiple land portions 33 or between the frame portion 32 and the land portion 33. The first steam passage 51A, the second steam passage 51B, and the third steam passage 51C may each extend linearly or may have any shape, such as a curved shape such as an arc or an S-shape, or a bent linear shape such as a V-shape or an L-shape. The basic configurations, such as the cross-sectional shapes, of the first steam passage 51A, the second steam passage 51B, and the third steam passage 51C are the same as the configuration of the steam passage 51 described above. In this specification, the first steam passage 51A, the second steam passage 51B, and the third steam passage 51C are collectively referred to simply as the steam passage 51.

[0066] The first steam passage 51A extends from the evaporation region SR, and its end in the extension direction does not contact the land portion 33. One end of the first steam passage 51A in the extension direction (negative side in the X direction) overlaps with the evaporation region SR. The other end of the first steam passage 51A in the extension direction (positive side in the X direction) is preferably located in the condensation region CR, which is spaced outward in the planar direction from the evaporation region SR. For example, it may terminate at a support portion 39 (described later). In this case, multiple (three) first steam passages 51A are provided, including one arranged along the first land portion 33A and one arranged along the frame portion 32. Of these, the first steam passage 51A arranged along the first land portion 33A is located between two first lands 33A. This first steam passage 51A has a substantially S-shaped curve in the middle and extends in the X direction as a whole in a planar view. Furthermore, the two first steam passages 51A arranged along the frame portion 32 each extend linearly along the X direction in a plan view.

[0067] The second steam passage 51B extends from the evaporation region SR, and its end in the extension direction contacts the first land portion 33A. That is, one end side of the second steam passage 51B in the extension direction (negative side in the X direction) overlaps with the evaporation region SR, and the other end in the extension direction (positive side in the X direction) contacts the first land portion 33A, terminating in this state. The first land portion 33A and the second land portion 33B are respectively arranged on both sides of the second steam passage 51B in the width direction (Y direction). In this embodiment, the second steam passage 51B extends linearly along the X direction in a plan view. In this embodiment, a plurality of second steam passages 51B (three passages) are provided, and these second steam passages 51B are arranged parallel to one another.

[0068] The third steam passage 51C is located outside the evaporation region SR, and its extension end contacts the first land portion 33A. That is, one extension end (negative X-direction side) of the third steam passage 51C is connected to the first land portion 33A. The other extension end (positive X-direction side) of the third steam passage 51C is preferably located in the condensation region CR, which is spaced outward in the planar direction from the evaporation region SR, and may terminate at a support portion 39 (described later), for example. The first land portion 33A or the third land portion 33C is disposed on both sides of the third steam passage 51C in the width direction (Y-direction). In this embodiment, the third steam passage 51C extends linearly along the X-direction in a planar view. Furthermore, in this embodiment, a plurality (three) of third steam passages 51C are provided, and these third steam passages 51C are arranged parallel to each other.

[0069] As shown in FIGS. 4 and 5 , 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 31 a 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 31 b side. The support portions 39 are indicated in gray in FIGS. 4 and 5 . The support portions 39 are thinned from the second main body surface 31 b 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.

[0070] 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.

[0071] 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.

[0072] As shown in FIGS. 3, 4, and 6, the liquid flow path portion 60 is provided on the second main body surface 31b of the wick sheet 30. The working fluid 2b 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 2b to the evaporation region SR. In this embodiment, the liquid flow path portion 60 is provided on the second main body surface 31b 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 31b of each land portion 33. Furthermore, the liquid flow path portion 60 may not be formed on some of the multiple lands 33. The liquid flow path portion 60 may also be referred to as a second main body surface groove.

[0073] As shown in Fig. 7 , the liquid flow path section 60 has a plurality of liquid flow path mainstream grooves 61, through which the working fluid 2b passes, that are arranged parallel to one another, and a plurality of liquid flow path communication grooves 65 that communicate with the liquid flow path mainstream grooves 61. In the example shown in Fig. 7 , 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.

[0074] 7, each liquid flow path main groove 61 is formed to extend along the extension direction (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.

[0075] 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 produced by condensation of 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 (the direction perpendicular to the extension direction of the land section 33, the Y direction).

[0076] 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 Figures 3 and 6, 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 sections shown in Figures 3 and 6, 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.

[0077] In FIG. 7 , 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 refers to the length in a direction perpendicular to the extension direction of the land portion 33 (a direction perpendicular to the longitudinal direction), and in this case, refers to the dimension in the Y direction. The width w3 of the liquid flow path mainstream groove 61 refers to the dimension at the second main body surface 31b. As shown in FIG. 3 , 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 refers to the distance measured from the second main body surface 31b in a direction perpendicular to the second main body surface 31b, and in this case, refers to the dimension in the Z direction. The depth h1 refers to the depth at the deepest point of the liquid flow path mainstream groove 61.

[0078] As shown in FIG. 7 , each liquid flow path communication groove 65 extends in a direction different from the extension direction (X direction) of the land portion 33. In this embodiment, each liquid flow path communication groove 65 is formed to extend in the width direction (Y direction) of the land portion 33 and is formed 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. Other liquid flow path communication grooves 65 are arranged to connect the steam flow path section 50 (steam passage 51) with 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 width direction end side of the land portion 33 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.

[0079] 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 extension direction (longitudinal direction, X direction) of the land section 33.

[0080] 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. 7, the width w4 of the liquid flow path communication grooves 65 (the dimension in the extension direction of the land portions 33) 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.

[0081] As shown in Fig. 7, 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. 7, 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.

[0082] As shown in Fig. 7, each of the convex rows 63 is formed to extend along the extension 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 extension direction of the land portion 33. The convex rows 63 are arranged at intervals from one another in the width direction (Y direction) of the land portion 33.

[0083] Each projection row 63 includes a plurality of projections 64 (liquid flow path protrusions) arranged in the extension direction of the land portion 33. The projections 64 are provided within the liquid flow path portion 60 and project from the liquid flow path mainstream grooves 61 and the liquid flow path connecting grooves 65 to abut against the upper sheet 20. Each projection 64 is formed in a rectangular shape in a plan view such that the extension direction of the land portion 33 is the longitudinal direction. A liquid flow path mainstream groove 61 is disposed between adjacent projections 64 in the width direction of the land portion 33. A liquid flow path connecting groove 65 is disposed between adjacent projections 64 in the extension direction of the land portion 33. The liquid flow path connecting groove 65 is formed to extend in the width direction of the land portion 33 and connects adjacent liquid flow path mainstream grooves 61 in the width direction of the land portion 33. This allows the hydraulic fluid 2b to move back and forth between these liquid flow path mainstream grooves 61.

[0084] The protrusions 64 are portions that are not etched away in the etching step described below, and the material of the wick sheet 30 remains. In this embodiment, as shown in Fig. 7, 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.

[0085] In this embodiment, the convex portions 64 are arranged in a staggered (alternate) pattern. More specifically, the convex portions 64 of convex portion rows 63 adjacent to each other in the width direction of the land portion 33 are arranged so as to be shifted from each other in the extension direction of the land portion 33. This shift amount may be half the arrangement pitch of the convex portions 64 in the extension direction of the land portion 33. Note that the arrangement of the convex portions 64 is not limited to a staggered pattern, and they may also be arranged in parallel. In this case, the convex portions 64 of the convex portion rows 63 adjacent to each other in the width direction of the land portion 33 are also aligned in the extension direction of the land portion 33.

[0086] The length L1 of the protrusions 64 (the dimension in the extension direction of the land portion 33) may be uniform among the protrusions 64. The length L1 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 the protrusions 64 refers to the maximum dimension measured along the extension direction of the land portion 33 on the second main body surface 31b.

[0087] As shown in FIGS. 3 , 5 , and 6 , the first body surface-side flow passage 70 is provided on the first body surface 31 a of the wick sheet 30. The first body surface-side flow passage 70 mainly serves as a liquid storage section for storing the working fluid 2 b, or serves to pass the working steam 2 a by communicating with the steam passage 51. This first body surface-side flow passage 70 constitutes part of the sealed space 3. The first body surface-side flow passage 70 communicates with the steam passage 51 and also communicates with the liquid flow passage section 60 via the steam passage 51. In this embodiment, the first body surface-side flow passage 70 is provided on the first body surface 31 a side of each of the first land portion 33A and the second land portion 33B. The first body surface-side flow passage 70 may not be formed in some of the multiple lands 33. The first body surface-side flow passage 70 may also be referred to as a first body surface-side groove.

[0088] As shown in Fig. 5, the first body surface-side flow passage 70 may be disposed on the evaporation region SR side. The first body surface-side flow passage 70 may be formed continuously or discontinuously from the extension direction end of the land portion 33 on the evaporation region SR side to a predetermined position toward the other extension direction end. The first body surface-side flow passage 70 may be disposed in the evaporation region SR, or a portion of the first body surface-side flow passage 70 may extend outside the evaporation region SR. When at least a portion of the first body surface-side flow passage 70 is disposed in the evaporation region SR, the working fluid 2b stored in the first body surface-side flow passage 70 is more likely to evaporate due to heat from the device D.

[0089] In this embodiment, the first body-surface-side flow passage 70 is also formed in a connection region MR, which is a region of the first land 33A where the extension direction end of the second steam passage 51B or the third steam passage 51C contacts the first land 33A. For example, in FIG. 5 , the connection region MR is circled and exists at a position where the extension direction end of the second steam passage 51B or the third steam passage 51C contacts the first land 33A. At least in this connection region MR, the first body-surface-side flow passage 70 is formed on the first body surface 31a side of the first land 33A. The first body-surface-side flow passage 70 is connected to the second steam passage 51B or the third steam passage 51C that contacts the first land 33A. As a result, working steam 2a from the second steam passage 51B or the third steam passage 51C flows through the first body-surface-side flow passage 70, crosses the first land 33A, and flows into the first steam passage 51A. The connection region MR may be located at a curved portion of the first land portion 33A in a plan view. In this case, the connection region MR can reduce the vapor resistance of the working vapor 2a flowing through the first body surface-side flow path 70, facilitating heat transfer within the vapor chamber 1.

[0090] As shown in FIG. 5 , in the first land portion 33A located on the positive side of the Y direction, the first main surface-side flow passage 70 is formed continuously along the first land portion 33A from the connection region MR to the evaporation region SR. In the first land portion 33A located on the negative side of the Y direction, the first main surface-side flow passage 70 is formed in each of the connection region MR and the evaporation region SR, but is not formed continuously from the connection region MR to the evaporation region SR. In each second land portion 33B, the first main surface-side flow passage 70 is formed continuously along the second land portion 33B from the connection region MR to the evaporation region SR. The third land portion 33C does not have the first main surface-side flow passage 70. However, this is not a limitation, and the first main surface-side flow passage 70 may be formed in the third land portion 33C.

[0091] As shown in Fig. 8 , the first main surface-side flow path 70 has a plurality of first main surface-side main grooves 71 arranged parallel to one another and a plurality of first main surface-side communication grooves 75 communicating with the first main surface-side main grooves 71. The first main surface-side main grooves 71 and the first main surface-side communication grooves 75 are grooves through which the working fluid 2b or working steam 2a passes. Note that, in the example shown in Fig. 8 , each land portion 33 includes five first main surface-side main grooves 71, but this is not limited to this. The number of first main surface-side main grooves 71 included in each land portion 33 is arbitrary and may be, for example, 2 to 20.

[0092] As shown in Fig. 8, each first main surface side main groove 71 is formed to extend along the longitudinal direction (X direction) of the land portion 33. The first main surface side main grooves 71 are arranged parallel to one another. If the land portion 33 is curved in a plan view, each first main surface side main groove 71 may extend in a curved shape along the curved direction of the land portion 33. In other words, each first main surface side main groove 71 does not necessarily have to be formed linearly, and does not necessarily have to extend parallel to the X direction.

[0093] Each first main surface side main groove 71 is formed within a predetermined range along the extension direction of the land portion 33. The first main surface side main groove 71 may have a flow path cross-sectional area through which the working fluid 2b flows by capillary action. The flow path cross-sectional area of ​​the first main surface side main groove 71 may be smaller than that of the steam passage 51. The flow path cross-sectional area of ​​the first main surface side main groove 71 may be larger than that of the liquid flow path main groove 61. The capillary force acting on the working fluid 2b in the first main surface side main groove 71 may be smaller than that acting on the working fluid 2b in the liquid flow path main groove 61. In this way, the first main surface side main groove 71 can draw the working fluid 2b into the first main surface side flow path 70 and ensure a sufficient storage amount of the working fluid 2b. The first main surface side main grooves 71 may be arranged at equal intervals in the width direction (Y direction).

[0094] The first main body surface-side main groove 71 is formed by etching from the first main body surface 31a of the wick sheet 30 in an etching process described below. As a result, the first main body surface-side main groove 71 has a curved wall surface 72, as shown in Figures 3 and 6. This wall surface 72 defines the first main body surface-side main groove 71 and is curved in a shape that bulges toward the second main body surface 31b.

[0095] As shown in FIG. 8 , the width w6 of the first main body surface-side main groove 71 may be larger than the width w3 of the liquid flow path main groove 61 described above. The width w6 may be, for example, 10 μm or more and 750 μm or less. The width w6 of the first main body surface-side main groove 71 refers to the dimension at the first main body surface 31a. The width w6 is the length in a direction perpendicular to the longitudinal direction of the land portion 33, which in this case is the dimension in the Y direction. Also, as shown in FIG. 6 , the depth h2 of the first main body surface-side main groove 71 may be larger than the depth h1 of the liquid flow path main groove 61 described above. The depth h2 may be, for example, 5 μm or more and 500 μm or less. The depth h2 corresponds to the dimension in the Z direction.

[0096] As shown in FIG. 8 , each first main surface side communication groove 75 extends in a direction different from the X direction. In this embodiment, each first main surface side communication groove 75 is formed to extend in the Y direction, perpendicular to the first main surface side main grooves 71. Some first main surface side communication grooves 75 connect adjacent first main surface side main grooves 71. Other first main surface side communication grooves 75 connect the steam flow path section 50 (steam passage 51) and the first main surface side main groove 71. That is, the first main surface side communication groove 75 extends from the end side of the land portion 33 in the Y direction to the first main surface side main groove 71 adjacent to that end. In this way, the steam passage 51 of the steam flow path section 50 and the first main surface side main groove 71 are connected to each other.

[0097] The first body-surface-side communication groove 75 may have a flow path cross-sectional area that allows the working fluid 2b to flow by capillary action. The flow path cross-sectional area of ​​the first body-surface-side communication groove 75 may be smaller than the flow path cross-sectional area of ​​the steam passage 51. The flow path cross-sectional area of ​​the first body-surface-side communication groove 75 may be larger than the flow path cross-sectional area of ​​the liquid flow path communication groove 65 described above. The capillary force acting on the working fluid 2b in the first body-surface-side communication groove 75 may be smaller than the capillary force acting on the working fluid 2b in the liquid flow path communication groove 65. In this way, the first body-surface-side communication groove 75 can draw the working fluid 2b into the first body-surface-side flow path 70 and ensure a storage amount of the working fluid 2b. The first body-surface-side communication grooves 75 may be arranged at equal intervals in the longitudinal direction (X direction) of the land portion 33.

[0098] The first body surface side communication groove 75, like the first body surface side main groove 71, is formed by etching and has a wall surface (not shown) formed in a curved shape similar to that of the first body surface side main groove 71. The width w7 of the first body surface side communication groove 75 may be equal to or different from the width w6 of the first body surface side main groove 71. The width w7 corresponds to the dimension in the X direction. The depth of the first body surface side communication groove 75 may be equal to or different from the depth h2 of the first body surface side main groove 71.

[0099] As shown in FIG. 8 , a convex portion row 73 is provided between adjacent first main surface side grooves 71. Each convex portion row 73 includes a plurality of convex portions 74 arranged along the longitudinal direction (X direction) of the land portion 33. The convex portions 74 are provided in the first main surface side flow passage 70. The convex portions 74 protrude from the first main surface side groove 71 and the first main surface side communication groove 75 and abut against the lower sheet 10. Each convex portion 74 is formed in a rectangular shape with the X direction as the longitudinal direction in a plan view. A first main surface side groove 71 is interposed between adjacent convex portions 74 in the Y direction. A first main surface side communication groove 75 is interposed between adjacent convex portions 74 in the X direction. The first main surface side communication groove 75 extends in the width direction of the land portion 33 and connects adjacent first main surface side grooves 71 in the width direction. This allows the working fluid 2 b or working steam 2 a to travel between these first main body surface side grooves 71 .

[0100] The protrusions 74 are portions that are not etched in the etching process described below, and the material of the wick sheet 30 remains. In this embodiment, the planar shape of the protrusions 74 is rectangular, as shown in Fig. 8. The planar shape of the protrusions 74 corresponds to the planar shape at the position of the first main body surface 31a.

[0101] In this embodiment, the convex portions 74 are arranged in a staggered pattern. More specifically, the convex portions 74 of adjacent convex portion rows 73 are arranged with a mutual offset in the X direction. This offset may be half the arrangement pitch of the convex portions 74 in the X direction. The width w8 of the convex portions 74 may be, for example, 10 μm or more and 100 μm or less. The width w8 of the convex portions 74 refers to the dimension at the first body surface 31a. The width w8 corresponds to the dimension in the width direction of the land portion 33. Note that the convex portions 74 are not limited to being arranged in a staggered pattern, but may also be arranged in parallel. In this case, the convex portions 74 of adjacent convex portion rows 73 in the width direction of the land portion 33 are also aligned in the X direction. Note that the width w6 of the first body surface-side main groove 71 may be greater than the width w3 of the liquid flow path main groove 61. Furthermore, the width w6 of the first body surface-side main groove 71 may be smaller than the width w2 of the steam passage 51.

[0102] The length L2 (dimension in the X direction) of each protrusion 74 may be uniform between the adjacent protrusions 74. The length L2 of each protrusion 74 is longer than the width w7 of the first body surface-side connecting groove 75 (L2>w7). Note that the length L2 of each protrusion 74 refers to the maximum dimension in the X direction on the first body surface 31a.

[0103] The number of first main body surface side grooves 71 provided in the land portion 33 may be less than the number of liquid flow path main grooves 61 provided in the land portion 33 .

[0104] FIG. 9 is an enlarged bottom view (enlarged view of portion VIII in FIG. 5 ) showing the periphery of the connection region MR of the wick sheet 30. As shown in FIG. 9 , the extension direction end (positive end in the X direction) of the second steam passage 51B contacts the first land portion 33A, forming the connection region MR in this region. The second land portion 33B is disposed on both sides of the second steam passage 51B in the width direction (Y direction). The second steam passage 51B and each second land portion 33B are positioned parallel to each other. Furthermore, a first steam passage 51A, which is a steam passage separate from the second steam passage 51B, is located on the side of the connection region MR opposite the side where the extension direction end (positive end in the X direction) of the second steam passage 51B contacts. That is, the first steam passage 51A is located on the opposite side of the second steam passage 51B from the first land portion 33A. The first steam passage 51A and the first land portion 33A are positioned parallel to each other.

[0105] A first main-body-surface-side flow passage 70 communicating with the second vapor passage 51B is formed in at least each connection region MR of the first land portion 33A. In this case, the first main-body-surface-side flow passage 70 is formed not only in the connection region MR but also in the region of the first land portion 33A surrounding the connection region MR. The first main-body-surface-side flow passage 70 is also formed continuously in the second land portion 33B connected to the first land portion 33A around the connection region MR. Furthermore, in the connection region MR, the first land portion 33A and the second vapor passage 51B intersect at a non-right angle in plan view. That is, the angle θ shown in FIG. 9 is an acute or obtuse angle. This facilitates the flow of working vapor 2a from the second vapor passage 51B along the extension direction of the first land portion 33A, allowing the working vapor 2a to be distributed over a wide area of ​​the vapor chamber 1.

[0106] 9 , the first body-face-side flow passage 70 of the first land portion 33A has a plurality of protrusions 74 arranged in a staggered pattern. A first body-face-side main groove 71 and a first body-face-side communication groove 75 are formed between each of the protrusions 74. This allows the second steam passage 51B and the first steam passage 51A to communicate with each other via the first body-face-side flow passage 70 of the first land portion 33A. Therefore, working steam 2a from the second steam passage 51B can flow to the first steam passage 51A side via the first body-face-side flow passage 70 of the first land portion 33A.

[0107] Additionally, a first body-surface-side flow passage 70 is formed in the second land portion 33B around the connection region MR. As a result, the working steam 2a from the second steam passage 51B flows from the first body-surface-side flow passage 70 of the second land portion 33B to the first steam passage 51A side via the first body-surface-side flow passage 70 of the first land portion 33A. This makes it easier for the working steam 2a from the second steam passage 51B to flow to the first steam passage 51A adjacent to the first land portion 33A. Note that the convex portion 74 of the first land portion 33A and the convex portion 74 of the second land portion 33B may be separated from each other, or the convex portion 74 of the first land portion 33A and the convex portion 74 of the second land portion 33B may be integrated with each other.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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 10(a) to 10(c). Figures 10(a) to 10(c) show cross sections that are substantially the same as the cross section shown in Figure 3.

[0113] First, the manufacturing process of the wick sheet 30 will be described.

[0114] First, as shown in FIG. 10( 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.

[0115] After the preparation process, as an etching process, as shown in Figure 10 (b), the metal material sheet M is etched from the first material surface Ma and the second material surface Mb to form the steam flow path section 50, the liquid flow path section 60, and the first main body surface side flow path 70.

[0116] 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, the liquid flow path portion 60, and the first body surface-side flow path 70 as shown in FIG. 10( b). Note that 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.

[0117] 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 section 50, the liquid flow path section 60, and the first main body surface side flow path 70 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. 4 and 5 . That is, the edge of the wick sheet 30 is formed.

[0118] In this manner, the wick sheet 30 according to this embodiment is obtained.

[0119] 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. 10(c) . The lower sheet 10 and the upper sheet 20 may be formed from rolled material having a desired thickness.

[0120] 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 31 a of the wick sheet 30 is superimposed on the second lower sheet surface 10 b of the lower sheet 10, and the first upper sheet surface 20 a of the upper sheet 20 is superimposed on the second main body surface 31 b of the wick sheet 30.

[0121] 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.

[0122] 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 between the lower sheet 10 and the upper sheet 20, the sealed space 3 having a vapor flow path portion 50, a liquid flow path portion 60, and a first main body surface-side flow path 70.

[0123] After the joining process, the hydraulic fluid 2 b is injected into the sealed space 3 from the injection portion 4 .

[0124] 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.

[0125] In this manner, the vapor chamber 1 according to this embodiment is obtained.

[0126] Next, the operation method of the vapor chamber 1, that is, the cooling method of the device D, will be described.

[0127] 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.

[0128] In this state, when the device D generates heat, the working fluid 2b present in the evaporation region SR (see FIGS. 4 and 5 ) 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. 4 ). 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. 4 and 5 ), 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 ).

[0129] In this embodiment, of the multiple steam passages 51, the first steam passage 51A extends from the evaporation region SR to the direct condensation region CR. Therefore, the working steam 2a passing through the first steam passage 51A reaches the direct condensation region CR. On the other hand, the second steam passage 51B extends from the evaporation region SR, and its extension direction end contacts the first land portion 33A. Therefore, the working steam 2a passing through the second steam passage 51B is blocked by the first land portion 33A and is not transported to the direct condensation region CR. In this embodiment, a first body surface-side flow path 70 communicating with the second steam passage 51B is formed in the connection region MR on the first body surface 31a side of the first land portion 33A and where the extension direction end of the second steam passage 51B contacts. As a result, the working steam 2a from the second steam passage 51B passes through the first body-surface-side passage 70, crosses the first land portion 33A, and flows into the first steam passage 51A located on the opposite side of the second steam passage 51B. The working steam 2a then passes through the first steam passage 51A and reaches the condensation region CR. Alternatively, some of the working steam 2a passes through the first body-surface-side passage 70 formed in another first land portion 33A and flows into the third steam passage 51C. The working steam 2a then passes through the third steam passage 51C and reaches the condensation region CR.

[0130] 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 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 the liquid flow path mainstream grooves 61 (see the dashed arrows in FIG. 4 ). As a result, the working fluid 2b adhering to the vapor passages 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 grooves 65, and enters the liquid flow path mainstream grooves 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.

[0131] 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.

[0132] 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.

[0133] Note that a portion of the working fluid 2b condensed in the condensation region CR is transported not only to the liquid flow path section 60 but also to the first body surface-side flow path 70, filling the first body surface-side flow path 70. As described above, a portion of the first body surface-side flow path 70 is disposed in the evaporation region SR. Therefore, the working fluid 2b filling the first body surface-side flow path 70 obtains a driving force due to the capillary action of the first body surface-side flow path 70 and moves toward the evaporation region SR. The working fluid 2b that reaches the evaporation region SR via the first body surface-side flow path 70 receives heat again from the device D, evaporates, and diffuses again within each vapor path 51.

[0134] While the device D stops generating heat, the working fluid 2b in the evaporation region SR does not evaporate but remains filled in the liquid flow path section 60. Therefore, the working fluid 2b in the condensation region CR remains there without being transported toward the evaporation region SR. A portion of the working fluid 2b in the liquid flow path section 60 flows through the vapor passage 51 and moves into the first body surface-side flow path 70. This causes the working fluid 2b to fill and remain in the first body surface-side flow path 70. If the amount of working fluid 2b sealed in the sealed space 3 is greater than the total volume of the space within the liquid flow path section 60, a portion of the working fluid 2b is likely to fill the first body surface-side flow path 70. Therefore, the working fluid 2b can be dispersed and remain not only in the liquid flow path section 60 but also in the first body surface-side flow path 70.

[0135] In this state, even if the electronic device E equipped with the vapor chamber 1 is placed in a temperature environment lower than the freezing point of the working fluids 2a and 2b, causing the working fluid 2b in the liquid flow path portion 60 to freeze and expand, the expansion force of the working fluids 2a and 2b is weakened. This prevents the upper sheet 20 from being deformed by the expansion force. 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 a gap from being formed between the second upper sheet surface 20b and the device D. This prevents the conduction of heat from the device D from being impeded, and prevents a decrease in the performance of the vapor chamber 1. Similarly, even if the working fluid 2b in the first body-side flow path 70 freezes and expands, the expansion force is weakened. This prevents the lower sheet 10 from being deformed by the expansion force. This prevents a decrease in the flatness of the first lower sheet surface 10a of the lower sheet 10.

[0136] According to this embodiment, the extension direction end of the second vapor passage 51B contacts at least the first land portion 33A among the multiple land portions 33. Furthermore, a first body surface-side flow passage 70 communicating with the second vapor passage 51B is formed in the connection region MR on the first body surface 31a side of the first land portion 33A, where the extension direction end of the second vapor passage 51B contacts. This allows the working vapor 2a transported from the evaporation region SR side via the second vapor passage 51B to be sent to the other first vapor passage 51A via the first body surface-side flow passage 70. This allows the working vapor 2a to be transported in a direction away from the evaporation region SR, thereby reducing areas within the vapor chamber 1 where heat is difficult to transfer. Furthermore, since a wide area of ​​the vapor chamber 1 can be used for heat transport, heat from the heat source can be distributed uniformly within the vapor chamber 1. As a result, the action of the working fluids 2a and 2b circulating within the sealed space 3 is promoted, and the temperature uniformity of the vapor chamber 1 can be improved.

[0137] Furthermore, according to this embodiment, the first main body surface-side flow passage 70 is formed continuously along the first land portion 33A to the evaporation region SR. This allows the first main body surface-side flow passage 70 to be used as a liquid flow passage for transporting the working fluid 2b to the evaporation region SR. As a result, the action of the working fluids 2a, 2b circulating within the sealed space 3 can be promoted.

[0138] Furthermore, according to this embodiment, the first body-surface-side flow passage 70 is also formed in the second land portion 33B extending along the second vapor passage 51B. In this case, the working vapor 2a transported from the evaporation region SR side via the second vapor passage 51B can be sent to the first body-surface-side flow passage 70 of the first land portion 33A via the first body-surface-side flow passage 70 of the second land portion 33B. This allows a wide range of the vapor chamber 1 to be used for transporting heat, allowing the heat from the heat source to be distributed uniformly within the surface of the vapor chamber 1.

[0139] (Modifications) Next, various modifications of the first embodiment will be described with reference to Figures 11 to 18. Figures 11 to 18 are enlarged bottom views showing portions of the wick sheet 30 according to the modifications. In Figures 11 to 18, the same parts as those in the embodiment shown in Figures 1 to 10 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0140] 11 , the first body-surface-side flow passages 70 do not have to be formed in each of the second land portions 33B located on both sides of the second steam passage 51B in the width direction. The first body-surface-side flow passages 70 do not have to be formed over the entire area of ​​the second land portion 33B. Alternatively, the first body-surface-side flow passages 70 may be formed on the evaporation region SR side of the second land portion 33B, but not on the connection region MR side of the second land portion 33B. In this case, the working steam 2a from the second steam passage 51B flows intensively along the extension direction of the second steam passage 51B (positive side in the X direction), allowing more working steam 2a to be transported toward the extension direction side of the second steam passage 51B (positive side in the X direction).

[0141] (Second Modification) As shown in Fig. 12 , the first land 33A and the second steam passage 51B may be perpendicular to each other in a plan view at the connection region MR of the first land 33A. That is, the angle θ in Fig. 12 may be 90°. In this case, the working steam 2a from the second steam passage 51B crosses the first land 33A perpendicularly to the extension direction, thereby minimizing the distance the working steam 2a travels through the first land 33A. This minimizes the steam resistance of the working steam 2a crossing the first land 33A.

[0142] (Third Modification) As shown in FIG. 13 , two second lands 33B may join and connect to a fourth land 33D. At this joining point, the extension direction end of the second steam passage 51B contacts the fourth land 33D. Furthermore, a first body surface-side flow path 70 communicating with the second steam passage 51B is formed in a connection region MR on the first body surface 31a side of the fourth land 33D where the extension direction end of the second steam passage 51B contacts. One extension direction end (negative end in the X direction) of the fourth land 33D may be connected to two second lands 33B, and the other extension direction end (positive end in the X direction) may be located in a condensation region CR spaced outward from the evaporation region SR in the planar direction. In this case, the second steam passage 51B has a shape in which its width (distance in the Y direction) gradually narrows toward the connection region MR located at the extension direction end of the second steam passage 51B.

[0143] According to this modification, the working steam 2a from the second steam passage 51B can be branched near the connection region MR and flow toward the steam passages 51 located on both sides of the fourth land portion 33D in the width direction (Y direction). This allows the working steam 2a to spread over a wide area of ​​the vapor chamber 1. Note that three or more second lands 33B may join and connect to the fourth land portion 33D.

[0144] 14 , a portion of the second land portion 33B located on the connection region MR side may be curved or bent and connected to the first land portion 33A. In this case, the end of the second steam passage 51B in the extension direction is in contact with the first land portion 33A. A first body surface-side flow path 70 communicating with the second steam passage 51B is formed in the connection region MR on the first body surface 31 a side of the first land portion 33A and where the end of the second steam passage 51B in the extension direction is in contact. The second steam passage 51B has a shape such that its width (distance in the Y direction) gradually narrows toward the connection region MR located at the end of the second steam passage 51B in the extension direction.

[0145] According to this modification, the working steam 2a from the second steam passage 51B branches off near the connection region MR and flows toward the steam passages 51 located on both sides of the first land portion 33A in the width direction (Y direction). This allows the working steam 2a to spread over a wide area of ​​the vapor chamber 1.

[0146] 15 to 18 are diagrams showing a fifth modified example, in which Fig. 15 to Fig. 17 are enlarged bottom views showing the periphery of the connection region MR of the wick sheet 30 according to this modified example.

[0147] 15 to 17 , a first body surface-side flow passage 70A is formed in a connection region MR on the first body surface 31a side of the first land portion 33A, where the end of the third steam passage 51C in the extension direction abuts. The first body surface-side flow passage 70A communicates with the first steam passage 51A and the third steam passage 51C. The connection region MR is thinned from the first body surface 31a side. In this case, the thickness of at least the portion of the first land portion 33A where the first body surface-side flow passage 70A is formed is thinner than the overall thickness of the wick sheet 30.

[0148] 15 to 17, the portions of the lands 33A, 33C that are thinned from the first body surface 31a side and in which the first body surface-side flow passages 70A are formed are shown in gray, and the portions of the lands 33A, 33C that are not thinned from the first body surface 31a side and in which neither the first body surface-side flow passages 70, 70A are formed are shown in white.

[0149] 15 , a first body-surface-side flow path 70A that communicates with the first steam passage 51A and the third steam passage 51C is formed in a connection region MR where the extension direction ends of the third steam passage 51C are in contact. A portion of the first land portion 33A adjacent to the connection region MR is not thinned from the first body surface 31a side, and none of the first body-surface-side flow paths 70, 70A is formed therein.

[0150] In this case, the working fluid 2b can be stored in the first main body surface-side flow path 70A when the vapor chamber 1 is stopped. Furthermore, when the vapor chamber 1 is operating, the working vapor 2a passes through the first main body surface-side flow path 70A, making it easier to flow into the third vapor passage 51C.

[0151] 16( a), a first main body surface-side flow path 70A communicating with the first steam passage 51A and the third steam passage 51C is formed in a connection region MR where the ends of the third steam passage 51C in the extension direction are joined. The first main body surface-side flow path 70A is also formed in a connection portion of the first land portion 33A with the third land portion 33C, and in a connection portion of the third land portion 33C with the first land portion 33A.

[0152] In this case, when the vapor chamber 1 is stopped, a larger amount of working liquid 2b can be stored in the first main body surface-side flow path 70A. Also, when the vapor chamber 1 is operating, the area through which the working vapor 2a can pass can be widened. Furthermore, the flow direction of the working vapor 2a can be controlled.

[0153] 16(b), a first body surface-side flow passage 70A communicating with the first steam passage 51A and the third steam passage 51C is formed in a connection region MR where the extension direction ends of the third steam passage 51C are adjacent. The first body surface-side flow passage 70A is also formed in a connection portion of the first land portion 33A with the third land portion 33C and in a connection portion of the third land portion 33C with the first land portion 33A. Furthermore, a first body surface-side flow passage 70A that is not thinned from the first body surface 31a side is formed in a position of the third land portion 33C adjacent to the first body surface-side flow passage 70A.

[0154] In this case, it is particularly preferable to locate the first body-surface-side flow passage 70 of the third land portion 33C in a position close to the condensation region CR, which makes it easier for the first body-surface-side flow passage 70 to suck up the working fluid 2b present in the third steam passage 51C and to flow the working fluid 2b into the adjacent first body-surface-side flow passage 70A.

[0155] As shown in FIG. 17A , a first body surface-side flow passage 70A communicating with the first steam passage 51A and the third steam passage 51C is formed in the connection region MR where the extension direction ends of the third steam passage 51C meet. The first body surface-side flow passage 70A is also formed in a portion of the first land 33A farther from the evaporation region SR than the connection region MR. Furthermore, a first body surface-side flow passage 70 that is not thinned from the first body surface 31a side is formed in a portion of the first land 33A closer to the evaporation region SR than the connection region MR. The first body surface-side flow passage 70 of the first land 33A extends continuously to the evaporation region SR. Furthermore, the first body surface-side flow passage 70 is also formed in the third land 33C.

[0156] In this case, the first main body surface-side flow passage 70 of the first land portion 33A can be used as a liquid flow passage that transports the working fluid 2b to the evaporation region SR. Also, the working fluid 2b stored in the first main body surface-side flow passage 70A can be easily transported to the evaporation region SR using the first main body surface-side flow passage 70.

[0157] As shown in FIG. 17B , a first body surface-side flow passage 70A communicating with the first steam passage 51A and the third steam passage 51C is formed in the connection region MR where the extension direction end of the third steam passage 51C meets. A portion of the first land 33A farther from the evaporation region SR than the connection region MR is not thinned from the first body surface 31a, and neither of the first body surface-side flow passages 70, 70A is formed. Furthermore, a portion of the first land 33A closer to the evaporation region SR than the connection region MR is formed with a first body surface-side flow passage 70 that is not thinned from the first body surface 31a. The first body surface-side flow passage 70 of the first land 33A extends continuously to the evaporation region SR. Furthermore, a first body surface-side flow passage 70 is also formed in the third land 33C.

[0158] In this case, the portion of the first land portion 33A adjacent to the connection region MR is not thinned from the first main body surface 31a side, so that deformation of the connection region MR in the thickness direction can be suppressed.

[0159] Although not shown in FIGS. 15 to 17, the first main body surface-side flow passage 70A may be formed in the connection region MR where the end of the second steam passage 51B in the extension direction is in contact.

[0160] 18A to 18C each show a cross section (cross section taken along line XVIII-XVIII in FIGS. 15 to 17) of the connection region MR of the first land portion 33A. The connection region MR of the first land portion 33A shown in FIGS. 15 to 17 may have any of the cross-sectional shapes shown in FIGS. 18A to 18C.

[0161] As shown in FIG. 18( a), the first main surface-side flow passage 70A may have multiple first main surface-side main grooves 71A and multiple convex portion rows 73A. The multiple first main surface-side main grooves 71A are arranged parallel to one another. Each convex portion row 73A is provided between adjacent first main surface-side main grooves 71A. Each convex portion row 73A includes multiple convex portions 74A arranged along the longitudinal direction of the first land portion 33A. The convex portions 74A are located closer to the second main surface 31b than the first main surface 31a and are spaced apart from the lower sheet 10. The convex portions 74A may be arranged in a staggered pattern in a plan view. Alternatively, each convex portion row 73A may include one convex portion 74A, which may extend linearly along the longitudinal direction of the first land portion 33A.

[0162] In this case, the convex portion 74A of the first main body surface-side flow path 70A is spaced apart from the first main body surface 31a, widening the space between the first land portion 33A and the lower sheet 10. This allows a larger amount of working fluid 2b to be stored in the first main body surface-side flow path 70A. Furthermore, when the vapor chamber 1 is operating, the working vapor 2a can be distributed over a wider area of ​​the vapor chamber 1.

[0163] 18(a), the first main body surface-side groove 71A and the convex portion row 73A may each extend in the flow direction of the working vapor 2a (the direction of the arrow in FIG. 18(a)). In this case, the flow of the working vapor 2a transported from the first vapor passage 51A is less likely to be disturbed, and the working vapor 2a can be sent to the third vapor passage 51C more efficiently. This allows the heat from the evaporation region SR to be distributed uniformly within the surface of the vapor chamber 1.

[0164] 18(b), the first main surface-side flow path 70A may have a first main surface-side main groove 71A and a pair of convex portions 74A located at both widthwise ends of the first main surface-side main groove 71A. Each convex portion 74A is located closer to the second main surface 31b than to the first main surface 31a. In other words, the convex portion 74A is spaced apart from the lower sheet 10. In this case, a larger amount of working fluid 2b can be stored in the first main surface-side flow path 70A.

[0165] 18(c), the first main body surface-side flow path 70A may have a flat surface 70s. The flat surface 70s is located closer to the second main body surface 31b than the first main body surface 31a. In other words, the flat surface 70s is spaced apart from the lower sheet 10. In this case, the working steam 2a can be more efficiently sent to the third steam passage 51C.

[0166] Second Embodiment Next, a second embodiment will be described with reference to Figures 19 to 36. Figures 19 to 36 are diagrams illustrating the second embodiment. In Figures 19 to 36, the same parts as those in the first embodiment shown in Figures 1 to 18 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0167] 19 to 26, 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 devices D1 and D2, which are heat sources (heat generating elements) housed in the electronic device E. The devices D1 and D2 may be the same as the device D described above.

[0168] As shown in FIG. 19 , electronic device E (e.g., a tablet terminal) includes a housing H, multiple (two in this case) devices D1 and D2 housed within the housing H, and a vapor chamber 1. The vapor chamber 1 is housed within the housing H and arranged so as to be in thermal contact with the devices D1 and D2. This allows the vapor chamber 1 to receive heat generated by the devices D1 and D2 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 devices D1 and D2 are effectively cooled. When the electronic device E is a tablet terminal, the devices D1 and D2 correspond to a central processing unit or the like. In this embodiment, the device D1 corresponds to a first heat source, and the device D2 corresponds to a second heat source.

[0169] Next, the vapor chamber 1 according to this embodiment will be described. As shown in Figures 20 and 21, 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.

[0170] As shown in Figure 20, on the wick sheet 30, there are arranged a first heat source region SR1 and a second heat source region SR2 (hereinafter also referred to as heat source regions SR1 and SR2), which are regions where the working fluids 2a and 2b evaporate, and a condensation region CR, which is a region where the working fluids 2a and 2b condense.

[0171] The first heat source region SR1 is a region overlapping the device D1, which is the first heat source, in a planar view, and is the region where the device D1 is attached. The second heat source region SR2 is a region overlapping the device D2, which is the second heat source, in a planar view, and is the region where the device D2 is attached. The heat source regions SR1 and SR2 can be located anywhere in the vapor chamber 1. In this embodiment, the heat source regions SR1 and SR2 are formed spaced apart from each other in the X direction. Heat from the devices D1 and D2 is transferred to the heat source regions SR1 and SR2, respectively, and this heat causes the liquid working fluid (referred to as working fluid 2b) to evaporate in the heat source regions SR1 and SR2. Therefore, the heat source regions SR1 and SR2 constitute evaporation regions where the working fluids 2a and 2b evaporate. The heat from the devices D1 and D2 can be transferred not only to the regions overlapping the devices D1 and D2 in a planar view, but also to the surrounding areas of these regions. Here, the plan view refers to the state when the vapor chamber 1 is viewed from a direction perpendicular to the surface that receives heat from the devices D1 and D2 (the second upper sheet surface 20b of the upper sheet 20) and the surface that releases the received heat (the first lower sheet surface 10a of the lower sheet 10). In other words, the plan view corresponds to the state when the vapor chamber 1 is viewed from above or below, as shown in FIG. 20 , for example.

[0172] The condensation region CR is a region that does not overlap with the devices D1 and D2 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 that exists in the plane of the vapor chamber 1, away from the heat source regions SR1 and SR2. 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.

[0173] 21 , 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 31 a and a second main body surface 31 b located on the opposite side of the first main body surface 31 a. The first main body surface 31 a is disposed on the side of the lower sheet 10, and the second main body surface 31 b is disposed on the side of the upper sheet 20.

[0174] In this embodiment, the land portion 33 extends in an elongated shape in a plan view. The planar shape of the land portion 33 can be any shape, such as an elongated rectangular shape, an arc, a curved shape such as a U-shape or an S-shape, or a bent linear shape such as a V-shape or an L-shape. In FIGS. 22 and 23 , the multiple lands 33 include those extending linearly in a plan view, L-shapes, and U-shapes. Each land portion 33 is spaced apart from other lands 33 in the width direction of the land portion 33. 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 of the land portion 33 (see FIG. 21 ) may be, for example, 30 μm or more and 3000 μm or less. Here, the width w1 of the land portion 33 is the dimension of the land portion 33 in a direction (width direction) perpendicular to the extension direction of the land portion 33, and means the dimension at the thickest position of the land portion 33 (for example, the position where the protrusion portion 55 is present).

[0175] As shown in FIGS. 22 and 23 , in this embodiment, the multiple steam passages 51 include a connecting steam passage 51F, an individual steam passage 51G, and a branch steam passage 51H. The connecting steam passage 51F, the individual steam passage 51G, and the branch steam passage 51H are all flow paths through which the working steam 2a passes, and are formed between the multiple land portions 33 or between the frame portion 32 and the land portion 33. The basic configurations, such as the cross-sectional shapes, of the connecting steam passage 51F, the individual steam passage 51G, and the branch steam passage 51H are the same as those of the steam passage 51 described above. The connecting steam passage 51F, the individual steam passage 51G, and the branch steam passage 51H may each extend linearly or may have any shape, such as a curved shape such as an arc or an S-shape, or a bent linear shape such as a V-shape or an L-shape. In this specification, the connecting steam passage 51F, the individual steam passage 51G, and the branch steam passage 51H are collectively referred to simply as the steam passage 51.

[0176] The connecting steam passage 51F is a steam flow path connecting the first heat source region SR1 and the second heat source region SR2. That is, one end of the connecting steam passage 51F in the extension direction overlaps with the first heat source region SR1, and the other end of the connecting steam passage 51F in the extension direction overlaps with the second heat source region SR2. Working steam 2a flows through the connecting steam passage 51F between the first heat source region SR1 side and the second heat source region SR2 side. In particular, when device D1 is operating and device D2 is stopped, working steam 2a flows from the first heat source region SR1 side toward the second heat source region SR2 side through the connecting steam passage 51F. On the other hand, when device D1 is stopped and device D2 is operating, working steam 2a flows from the second heat source region SR2 side toward the first heat source region SR1 side through the connecting steam passage 51F.

[0177] The individual steam passage 51G is a steam flow path connected to either the first heat source region SR1 or the second heat source region SR2, but not the other. That is, one end of the individual steam passage 51G in the extension direction overlaps with either the first heat source region SR1 or the second heat source region SR2, and the other end does not overlap with either the first heat source region SR1 or the second heat source region SR2. The other end of the individual steam passage 51G in the extension direction is preferably located in the condensation region CR, which is located away from the heat source regions SR1 and SR2 in the planar direction. For example, it may terminate at a support portion 39 (described later). In the individual steam passage 51G, the working steam 2a flows from the first heat source region SR1 or the second heat source region SR2 outward in the planar direction. In particular, the working steam 2a flows from the heat source regions SR1 and SR2 corresponding to the driven devices D1 and D2 in the planar direction. In addition, the wick sheet 30 may be provided with an individual steam passage 51G connected to one of the heat source regions SR1 and SR2, and may not be provided with an individual steam passage 51G connected to the other.

[0178] The branch steam passage 51H is a steam passage connected to the connecting steam passage 51F midway in the extension direction and does not overlap either of the heat source regions SR1 and SR2. That is, one end of the branch steam passage 51H is connected to the connecting steam passage 51F, and the other end is located outside the heat source regions SR1 and SR2. The other end of the branch steam passage 51H is preferably located in the condensation region CR, which is located away from the heat source regions SR1 and SR2 in the planar direction. For example, the other end may terminate at a support portion 39 (described later). Alternatively, the other end of the branch steam passage 51H may be connected to another steam passage 51. In the branch steam passage 51H, working steam 2a flows from the connecting steam passage 51F toward the planar direction. In particular, when device D1 is operating and device D2 is stopped, working steam 2a flows from the first heat source region SR1 toward the outside in the planar direction via the connecting steam passage 51F and the branch steam passage 51H. On the other hand, when device D1 is stopped and device D2 is operating, working steam 2a flows from the second heat source region SR2 toward the outside in the planar direction via the connecting steam passage 51F and the branch steam passage 51H. Furthermore, when both devices D1 and D2 are operating, working steam 2a flows from the heat source regions SR1 and SR2 toward the outside in the planar direction via the connecting steam passage 51F and the branch steam passage 51H. Note that the branch steam passage 51H does not necessarily have to be provided within the wick sheet 30. Furthermore, when another heat source region (for example, a third heat source region SR3 described below) is provided, the branch steam passage 51H may overlap with the other heat source region.

[0179] As shown in FIGS. 22 and 23 , support portions 39 are provided within the vapor flow path 50 to support the extension direction ends of the land portions 33 on the frame portion 32. The support portions 39 may support adjacent land portions 33 or a single land portion 33. The support portions 39 are provided along one side of the frame portion 32 (in this case, the side located on the negative Y-direction). The support portions 39 may be provided on some or all of the sides constituting the frame portion 32. The support portions 39 are preferably formed so as not to interfere with the flow of the working steam 2a diffusing through the vapor flow path 50. In this case, the support portions 39 are disposed on the first body surface 31 a side of the wick sheet 30, and a space communicating with the vapor flow path 50 is formed on the second body surface 31 b side. The support portions 39 are indicated in gray in FIGS. 22 and 23 . The support portions 39 are thinned from the second body surface 31 b 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 flow path portion 50 from being divided by the support portion 39. 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 flow path 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.

[0180] As shown in FIG. 22 , in this embodiment, the multiple liquid flow path sections 60 include a connected liquid flow path 60A, an individual liquid flow path 60B, and an independent liquid flow path 60D. The connected liquid flow path 60A, the individual liquid flow path 60B, and the independent liquid flow path 60D are all flow paths through which the working fluid 2b passes, and are formed on each land portion 33. The basic configurations, such as the shapes of the connected liquid flow path 60A, the individual liquid flow path 60B, and the independent liquid flow path 60D, may be the same as the configuration of the liquid flow path section 60 in the first embodiment. The connected liquid flow path 60A, the individual liquid flow path 60B, and the independent liquid flow path 60D each extend linearly along the shape of the corresponding land portion 33. In this specification, the connected liquid flow path 60A, the individual liquid flow path 60B, and the independent liquid flow path 60D are collectively referred to simply as the liquid flow path section 60.

[0181] The connecting liquid flow path 60A is a liquid flow path connecting the first heat source region SR1 and the second heat source region SR2. That is, one end of the connecting liquid flow path 60A in the extension direction overlaps with the first heat source region SR1, and the other end of the connecting liquid flow path 60A in the extension direction overlaps with the second heat source region SR2. The connecting liquid flow path 60A allows the working liquid 2b to flow between the first heat source region SR1 side and the second heat source region SR2 side. In particular, when the device D1 is operating and the device D2 is stopped, the connecting liquid flow path 60A allows the working liquid 2b to flow from the second heat source region SR2 side toward the first heat source region SR1 side. On the other hand, when the device D1 is stopped and the device D2 is operating, the connecting liquid flow path 60A allows the working liquid 2b to flow from the first heat source region SR1 side toward the second heat source region SR2 side.

[0182] The individual liquid flow path 60B is a liquid flow path connected to either the first heat source region SR1 or the second heat source region SR2, but not the other. That is, one end of the individual liquid flow path 60B in the extension direction overlaps with the first heat source region SR1 or the second heat source region SR2, and the other end does not overlap with the first heat source region SR1 or the second heat source region SR2. The other end of the individual liquid flow path 60B in the extension direction is preferably located in the condensation region CR, which is located away from the heat source regions SR1 and SR2 in the planar direction, and may terminate at the support portion 39, for example. In the individual liquid flow path 60B, the working fluid 2b flows from the condensation region CR, which is located outward in the planar direction, toward the first heat source region SR1 or the second heat source region SR2. In particular, the working fluid 2b flows from the condensation region CR toward the heat source regions SR1 and SR2 corresponding to the driven devices D1 and D2. In addition, the wick sheet 30 may be provided with a separate liquid flow path 60B connected to one of the heat source regions SR1 and SR2, and may not be provided with a separate liquid flow path 60B connected to the other.

[0183] The independent liquid flow path 60D is a liquid flow path that is not connected to other liquid flow path sections 60 (such as the connecting liquid flow path 60A or the individual liquid flow path 60B) and does not overlap either of the heat source regions SR1 and SR2. In other words, both ends of the independent liquid flow path 60D in the extension direction are located outside of other liquid flow path sections 60 and outside of the heat source regions SR1 and SR2. One end of the independent liquid flow path 60D in the extension direction is preferably located in the condensation region CR, which is located away from the heat source regions SR1 and SR2 in the planar direction. For example, it may terminate at the support portion 39 described above. In the independent liquid flow path 60D, the working fluid 2b flows from the planar direction outside toward the heat source regions SR1 and SR2. Note that the independent liquid flow path 60D does not necessarily have to be provided within the wick sheet 30.

[0184] Fig. 24 is an enlarged view showing the top surface of each liquid flow path section 60 (connected liquid flow path 60A, individual liquid flow path 60B, or independent liquid flow path 60D). As shown in Fig. 24, the liquid flow path section 60 has a plurality of liquid flow path mainstream grooves 61, through which the working fluid 2b passes, that are arranged parallel to one another, and a plurality of liquid flow path connecting grooves 65 that communicate with the liquid flow path mainstream grooves 61. Note that in the example shown in Fig. 24, 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.

[0185] Next, the positional relationship between the first heat source region SR1, the second heat source region SR2, the connecting steam passage 51F, and the connecting liquid flow path 60A will be described with reference to Figures 25(a) and 25(b). Figures 25(a) and 25(b) are schematic top views showing the wick sheet 30. For convenience, elements other than the first heat source region SR1, the second heat source region SR2, the connecting steam passage 51F, and the connecting liquid flow path 60A are omitted from Figures 25(a) and 25(b).

[0186] As shown in FIG. 25A, a first heat source region SR1 and a second heat source region SR2 are arranged spaced apart from each other on the wick sheet 30. In this case, the center-to-center distance between the first heat source region SR1 and the second heat source region SR2 is indicated by La. The center-to-center distance La is the shortest distance on the wick sheet 30 between the center C1 of the first heat source region SR1 and the center C2 of the second heat source region SR2. In FIG. 25A, the center-to-center distance La is equal to the length of the line segment connecting the centers C1 and C2. The center C1 of the first heat source region SR1 and the center C2 of the second heat source region SR2 may be the centers of gravity of the first heat source region SR1 and the second heat source region SR2, respectively.

[0187] 25(b), it is possible that the line segment connecting the center C1 of the first heat source region SR1 and the center C2 of the second heat source region SR2 deviates from the plane of the wick sheet 30. In this case, the center-to-center distance La refers to the length of the shortest line connecting the centers C1 and C2 that passes through the plane of the wick sheet 30.

[0188] 25( a), the first heat source region SR1 and the second heat source region SR2 are connected to each other by a connecting steam passage 51F and a connecting liquid flow path 60A. In this case, the lengths of the connecting steam passage 51F and the connecting liquid flow path 60A are indicated by Lb and Lc, respectively. The length Lb of the connecting steam passage 51F is the length connecting the centers of the connecting steam passage 51F in the width direction and refers to the length of the region that does not overlap with the heat source regions SR1 and SR2. The length Lc of the connecting liquid flow path 60A is the length connecting the centers of the connecting liquid flow path 60A in the width direction and refers to the length of the region that does not overlap with the heat source regions SR1 and SR2.

[0189] In this case, it is preferable that the length Lb of the connecting steam passage 51F is equal to or less than twice the center-to-center distance La (Lb<2La). By setting the length Lb of the connecting steam passage 51F equal to or less than twice the center-to-center distance La, the middle part of the connecting steam passage 51F is not excessively separated from the heat source regions SR1 and SR2. This makes it possible to prevent the working steam 2a from condensing and turning into the working liquid 2b midway through the connecting steam passage 51F.

[0190] Similarly, the length Lc of the connecting liquid flow path 60A is preferably set to be equal to or less than twice the center-to-center distance La (Lc<2La). By setting the length Lc of the connecting liquid flow path 60A to be equal to or less than twice the center-to-center distance La, the intermediate portion of the connecting liquid flow path 60A is prevented from being excessively separated from the heat source regions SR1 and SR2. This prevents the working steam 2a from condensing into the working liquid 2b in the connecting steam passage 51F adjacent to the connecting liquid flow path 60A, which is located away from the heat source regions SR1 and SR2.

[0191] As shown in FIG. 22, the lengths Lb and Lc of the connecting vapor passage 51F and the connecting liquid passage 60A may be equal to or less than 1 time the center-to-center distance La between the first heat source region SR1 and the second heat source region SR2.

[0192] In the present embodiment, the first heat source region SR1 and the second heat source region SR2 are connected to each other by at least one connecting steam passage 51F and at least one connecting liquid passage 60A. However, this is not limited to this. For example, the first heat source region SR1 and the second heat source region SR2 may be connected to each other by at least one connecting steam passage 51F, but not by the connecting liquid passage 60A. Alternatively, the first heat source region SR1 and the second heat source region SR2 may be connected to each other by at least one connecting liquid passage 60A, but not by the connecting steam passage 51F.

[0193] 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 (see FIG. 10).

[0194] The method of operating the vapor chamber 1 according to this embodiment is substantially the same as that of the first embodiment, except that a plurality of devices D1 and D2 are provided.

[0195] In this embodiment, a plurality of (two) devices D1 and D2 are attached to the vapor chamber 1. In this case, the devices D1 and D2 may both be driven at the same time, or only one of the devices D1 and D2 may be driven.

[0196] 26(a)-(c) respectively show the cases where both devices D1 and D2 are driven (FIG. 26(a)), only device D1 is driven (FIG. 26(b)), and only device D2 is driven (FIG. 26(c)) in the wick sheet 30 shown in FIG. 22. In FIGS. 26(a)-(c), the heat source regions SR1 and SR2 corresponding to the driven devices D1 and D2 are indicated by thick lines, and the heat source regions SR1 and SR2 corresponding to the inactive devices D1 and D2 are indicated by dashed double-dashed lines.

[0197] 26(a), when both devices D1 and D2 are operating, the working vapor 2a generated in the heat source regions SR1 and SR2 is transported from the heat source regions SR1 and SR2 to the condensation region CR via the connecting vapor passage 51F and the branch vapor passage 51H in that order. The working vapor 2a is then converted into working liquid 2b in the condensation region CR, and the working liquid 2b is returned to the heat source regions SR1 and SR2 via the individual liquid flow path 60B.

[0198] Alternatively, a portion of the working steam 2a generated from the heat source regions SR1 and SR2 is transported to the condensation region CR through the individual steam passages 51G extending from the heat source regions SR1 and SR2. Thereafter, the working steam 2a is transformed into working liquid 2b in the condensation region CR, and this working liquid 2b is returned to the heat source regions SR1 and SR2 through the individual liquid passages 60B.

[0199] 26(b), when only device D1 is operating, working vapor 2a generated in first heat source region SR1 passes through connecting vapor passage 51F to second heat source region SR2 and is transported to condensation region CR via single vapor passage 51G extending from second heat source region SR2. Thereafter, working vapor 2a changes into working liquid 2b in condensation region CR, and this working liquid 2b passes through second heat source region SR2 via single liquid passage 60B extending from second heat source region SR2 and is returned to first heat source region SR1 via connecting liquid passage 60A.

[0200] Alternatively, a portion of the working steam 2a generated in the first heat source region SR1 is transported to the condensation region CR through the separate steam passage 51G extending from the first heat source region SR1. Thereafter, the working steam 2a is transformed into working liquid 2b in the condensation region CR, and this working liquid 2b is returned to the first heat source region SR1 through the separate liquid passage 60B extending from the first heat source region SR1.

[0201] 26(c), when only device D2 is operating, working vapor 2a generated in second heat source region SR2 passes through connecting vapor passage 51F to first heat source region SR1 and is transported to condensation region CR via single vapor passage 51G extending from first heat source region SR1. Thereafter, working vapor 2a changes into working liquid 2b in condensation region CR, and this working liquid 2b passes through first heat source region SR1 via single liquid passage 60B extending from first heat source region SR1 and is returned to second heat source region SR2 via connecting liquid passage 60A.

[0202] Alternatively, a portion of the working steam 2a generated in the second heat source region SR2 is transported to the condensation region CR through the separate steam passage 51G extending from the second heat source region SR2. Thereafter, the working steam 2a is transformed into working liquid 2b in the condensation region CR, and this working liquid 2b is returned to the second heat source region SR2 through the separate liquid passage 60B extending from the second heat source region SR2.

[0203] According to this embodiment, the first heat source region SR1 and the second heat source region SR2 are connected to each other by at least one connecting vapor passage 51F. This allows the working vapor 2a generated from the heat source region SR1 (SR2) corresponding to the driven device D1 (D2) to be transported to the condensation region CR via the connecting vapor passage 51F. The first heat source region SR1 and the second heat source region SR2 are also connected to each other by at least one connecting liquid passage 60A. This allows the working fluid 2b generated in the condensation region CR to be returned to the first heat source region SR1 (second heat source region SR2) via the connecting liquid passage 60A. This allows the working vapor 2a to be transported away from the heat source and the condensed working fluid 2b to be returned to the heat source, not only when both devices D1 and D2 are driven, but also when only one device D1 (D2) is driven. As a result, the areas within the surface of the vapor chamber 1 where heat is difficult to transfer are reduced, a wider area of ​​the vapor chamber 1 can be used for heat transport, and heat from the heat source can be distributed evenly within the surface of the vapor chamber 1.

[0204] According to this embodiment, the steam passage 51 includes a separate steam passage 51G that is connected to either the first heat source region SR1 or the second heat source region SR2 but not to the other, so that the working steam 2a generated from the heat source region SR1 (SR2) corresponding to the driven device D1 (D2) can be transported to the condensation region CR via the separate steam passage 51G.

[0205] Furthermore, according to this embodiment, the steam passage 51 includes a branch steam passage 51H connected to the connecting steam passage 51F. As a result, when both devices D1 and D2 are operating, the working steam 2a generated from the heat source regions SR1 and SR2 can be transported to the condensation region CR side via the connecting steam passage 51F and the branch steam passage 51H in this order.

[0206] Furthermore, according to this embodiment, the liquid flow path section 60 includes an individual liquid flow path 60B that is connected to either the first heat source region SR1 or the second heat source region SR2 but not the other. This allows the working fluid 2b condensed in the condensation region CR to be returned to the first heat source region SR1 or the second heat source region SR2 via the individual liquid flow path 60B.

[0207] (Modified Examples of Wick Sheet) Next, various modified examples of the wick sheet according to the second embodiment will be described with reference to Figures 27 to 35. Figures 27 to 35 are enlarged top views showing modified wick sheets 30. In Figures 27 to 35, the same parts as those shown in Figures 19 to 26 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0208] (First Modification of Wick Sheet) As shown in Fig. 27, the first heat source region SR1 and the second heat source region SR2 are connected to each other by a connecting liquid flow path 60A. On the other hand, in Fig. 27, the first heat source region SR1 and the second heat source region SR2 are not connected to each other by a connecting vapor passage 51F.

[0209] Furthermore, a branch liquid flow path 60C is connected to the connecting liquid flow path 60A in the extension direction. The branch liquid flow path 60C is a liquid flow path that is connected to the connecting liquid flow path 60A and does not overlap with either of the heat source regions SR1 or SR2. By providing the branch liquid flow path 60C in this manner, the working fluid 2b condensed in the condensation region CR can be returned to the heat source regions SR1 and SR2 via the branch liquid flow path 60C and the connecting liquid flow path 60A in this order.

[0210] Furthermore, a bridge 41 is formed midway along the extension direction of the connecting liquid flow path 60A. The bridge 41 is thinned from the rear surface (first main body surface 31a) side. The thinned portion of the bridge 41 communicates with the vapor passage 51E that intersects with the connecting liquid flow path 60A. By providing the bridge 41, it is possible to ensure the flow of working fluid 2b through the connecting liquid flow path 60A located on the front surface (second main body surface 31b) side, while preventing the flow of working steam 2a from being obstructed in the vapor passage 51E located on the rear surface side.

[0211] 28(a) and 28(b), the first heat source region SR1 and the second heat source region SR2 are connected to each other by a plurality of connecting steam passages 51F and a plurality of connecting liquid flow paths 60A, and branch steam passages 51H are connected to some of the connecting steam passages 51F. In addition, an independent liquid flow path 60D is arranged adjacent to the branch steam passage 51H. The independent liquid flow path 60D extends parallel to the plurality of individual liquid flow paths 60B extending from the heat source regions SR1 and SR2, respectively. The arrangement of the independent liquid flow path 60D makes it easier to collect the working fluid 2b within the surface of the wick sheet 30.

[0212] 28(a), a plurality of branch steam passages 51H may be connected to some of the connecting steam passages 51F. This allows the working steam 2a to flow efficiently from the heat source regions SR1 and SR2 toward the condensation region CR through the plurality of branch steam passages 51H, particularly when both devices D1 and D2 are operating.

[0213] 28(b), a portion of the individual vapor passage 51G extending from the second heat source region SR2 may have a curved portion R that is curved in a curved shape in a planar view. Furthermore, the individual liquid flow path 60B adjacent to this individual vapor passage 51G is also curved in a curved shape in a planar view, similar to the individual vapor passage 51G. By having the curved portion R in the individual vapor passage 51G, the vapor resistance of the working vapor 2a flowing through the individual vapor passage 51G can be reduced, facilitating heat transfer within the surface of the vapor chamber 1. Note that the individual vapor passage 51G is not limited to the individual vapor passage 51G, and the connecting vapor passage 51F or the branch vapor passage 51H may also be curved in a curved shape in a planar view.

[0214] 29(a) and 29(b), the wick sheet 30 may be T-shaped in plan view. In this case, the wick sheet 30 has a first end 30a, a second end 30b located on the opposite side of the first end 30a, and a third end 30c located laterally relative to the first end 30a and the second end 30b.

[0215] In FIG. 29( a), the first heat source region SR1 is located on the first end 30a side, and the second heat source region SR2 is located on the third end 30c side. The condensation region CR is located on the second end 30b side. The first heat source region SR1 and the second heat source region SR2 are connected to each other by a connecting steam passage 51F that is L-shaped in plan view and a connecting liquid flow path 60A that is L-shaped in plan view. A branch liquid flow path 60C is connected to a portion of the connecting liquid flow path 60A. Furthermore, an individual steam passage 51G that is linear in plan view and an individual liquid flow path 60B that is linear in plan view are connected to the first heat source region SR1. Furthermore, an individual steam passage 51G that is L-shaped in plan view and an individual liquid flow path 60B that is L-shaped in plan view are connected to the second heat source region SR2.

[0216] In FIG. 29( b), the first heat source region SR1 is located on the first end 30a side, and the second heat source region SR2 is located on the second end 30b side. The condensation region CR is located on the third end 30c side. The first heat source region SR1 and the second heat source region SR2 are connected to each other by a connecting vapor passage 51F that is linear in plan view and a connecting liquid flow path 60A that is linear in plan view. A branch liquid flow path 60C is connected to a portion of the connecting liquid flow path 60A. Furthermore, an L-shaped individual vapor passage 51G and an L-shaped individual liquid flow path 60B are connected to the first heat source region SR1. Furthermore, an L-shaped individual vapor passage 51G and an L-shaped individual liquid flow path 60B are connected to the second heat source region SR2.

[0217] According to this modification, when only one of the devices D1 (D2) is driven, the working vapor 2a can be transported to the non-driven device D2 (D1). That is, the area on the non-driven device D2 (D1) side can be used as the condensation region CR. This allows a wide area within the surface of the vapor chamber 1 to be used for heat transport, and the heat from the heat source can be distributed uniformly within the surface of the vapor chamber 1.

[0218] (Fourth Modification of Wick Sheet) As shown in Figures 30(a)-(c), the wick sheet 30 may be approximately H-shaped in plan view. In this case, the wick sheet 30 has a first end 30a, a second end 30b located opposite the first end 30a, and a third end 30c located laterally relative to the first end 30a and the second end 30b. In Figures 30(a)-(c), the first heat source region SR1 is located on the first end 30a side, and the second heat source region SR2 is located on the second end 30b side. The condensation region CR is located on the third end 30c side.

[0219] 30(a)-(c), the first heat source region SR1 and the second heat source region SR2 are connected to each other by a connecting vapor passage 51F that is linear in plan view and a connecting liquid flow path 60A that is linear in plan view. A branch liquid flow path 60C is connected to a portion of the connecting liquid flow path 60A. Furthermore, an individual vapor passage 51G and an individual liquid flow path 60B are each connected to the first heat source region SR1. Furthermore, an individual vapor passage 51G and an individual liquid flow path 60B are each connected to the second heat source region SR2.

[0220] In FIG. 30(a), the individual steam passage 51G, the individual liquid passage 60B and the branch liquid passage 60C extending from the heat source regions SR1 and SR2 toward the third end 30c each have a bent portion that bends at a right angle in a plan view.

[0221] In FIG. 30( b), the individual vapor passage 51G, the individual liquid passage 60B, and the branch liquid passage 60C extending from the heat source regions SR1 and SR2 toward the third end 30c each have a curved portion R that is curved in a curved shape in a plan view. This reduces the vapor resistance of the working vapor 2a flowing through the individual vapor passage 51G and facilitates heat transfer within the surface of the vapor chamber 1. The branch liquid passage 60C and the connecting liquid passage 60A are also curved at their connection points, and a connection recess 68 without a liquid passage is present at this connection point. While the connection recess 68 has a generally triangular shape in a plan view, it may have a planar shape corresponding to the shapes of the surrounding branch liquid passages 60C and connecting liquid passage 60A. This prevents the working liquid 2b from accumulating at the connection points between the branch liquid passage 60C and connecting liquid passage 60A. This prevents the working liquid 2b remaining on the connection points from freezing and damaging the vapor chamber 1 when the vapor chamber 1 is placed in an environment below the freezing point of the working liquid 2b.

[0222] In Figure 30(c), the connection between the branch liquid flow path 60C and the connecting liquid flow path 60A is curved, and a connecting liquid flow path 69 having a liquid flow path is present at this connection. The connecting liquid flow path 69 is generally triangular in plan view, but is not limited to this and may have a planar shape that corresponds to the shapes of the branch liquid flow path 60C and the connecting liquid flow path 60A located around it. This makes it easier for the operating liquid 2b from the branch liquid flow path 60C to flow toward the connecting liquid flow path 60A via the connecting liquid flow path 69. The rest of the configuration is the same as the configuration shown in Figure 30(b).

[0223] 31(a) and 31(b), in addition to the first heat source region SR1 and the second heat source region SR2, a third heat source region SR3 is also arranged on the wick sheet 30. A device D3, which is a third heat source, is arranged in the third heat source region SR3. Note that in FIGS. 31(a) and 31(b), the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 are arranged in this order from the negative side in the X direction, but the positional relationship between the heat source regions SR1, SR2, and SR3 is not limited to this.

[0224] 31(a) and 31(b), the first heat source region SR1 and the second heat source region SR2 are connected to each other by a connecting steam passage 51F and a connecting liquid flow path 60A. A branch steam passage 51H is connected to a portion of the connecting steam passage 51F. In addition, an individual steam passage 51G and an individual liquid flow path 60B are connected to the first heat source region SR1 and the second heat source region SR2, respectively. Note that the first heat source region SR1 and the second heat source region SR2 may be connected to each other by either the connecting steam passage 51F or the connecting liquid flow path 60A.

[0225] The second heat source region SR2 and the third heat source region SR3 are connected to each other by a connecting steam passage 51F and a connecting liquid flow path 60A. A branch steam passage 51H is connected to a portion of the connecting steam passage 51F. The third heat source region SR3 is connected to an individual steam passage 51G and an individual liquid flow path 60B. The second heat source region SR2 and the third heat source region SR3 may be connected to each other by either the connecting steam passage 51F or the connecting liquid flow path 60A.

[0226] An independent liquid flow path 60D is disposed adjacent to the branch steam passage 51H. The independent liquid flow path 60D extends parallel to the individual liquid flow paths 60B extending from the heat source regions SR1, SR2, and SR3. The arrangement of the independent liquid flow path 60D facilitates recovery of the working fluid 2b within the surface of the wick sheet 30.

[0227] 31( a), a portion of the individual vapor passage 51G extending from the third heat source region SR3 has a curved portion R that is curved in a curved shape in a planar view. The individual liquid flow path 60B adjacent to this individual vapor passage 51G is also curved in a curved shape in a planar view, similar to the individual vapor passage 51G. By having the curved portion R in the individual vapor passage 51G, the vapor resistance of the working vapor 2a flowing through the individual vapor passage 51G can be reduced, and heat can be easily transferred within the surface of the vapor chamber 1.

[0228] 31(b), the connecting vapor passage 51F connecting the second heat source region SR2 and the third heat source region SR3 has a curved portion R that is curved in a curved shape in a plan view. The connecting liquid flow path 60A adjacent to this connecting vapor passage 51F is also curved in a curved shape in a plan view, similar to the connecting vapor passage 51F. By having the curved portion R in the connecting vapor passage 51F, the vapor resistance of the working vapor 2a flowing through the connecting vapor passage 51F can be reduced, making it easier to transfer heat within the plane of the vapor chamber 1.

[0229] According to this modification, when one or two of the three devices D1-D3 are operating, the working vapor 2a can be transported to the non-operating device. This allows a wide area within the surface of the vapor chamber 1 to be used for heat transport, and heat from the heat source can be distributed uniformly within the surface of the vapor chamber 1. Four or more heat source regions may be arranged on the wick sheet 30.

[0230] (Sixth Modification of Wick Sheet) As shown in Figure 32, a first heat source region SR1, a second heat source region SR2, and a third heat source region SR3 are arranged on the wick sheet 30. In this case, some of the individual steam passages 51G connected to the first heat source region SR1 have a curved portion Ra that is U-shaped in plan view. At this curved portion Ra, the flow direction of the individual steam passage 51G changes by 180 degrees. The individual liquid flow path 60B adjacent to this individual steam passage 51G is also U-shaped in plan view, similar to the individual steam passage 51G. By having the U-shaped curved portion Ra of the individual steam passage 51G, the working steam 2a can be transported to a position away from the heat source regions SR1, SR2, and SR3.

[0231] A branch steam passage 51H is connected to a portion of the connecting steam passage 51F. An independent liquid flow path 60D is arranged adjacent to the branch steam passage 51H. The independent liquid flow path 60D extends parallel to the multiple individual liquid flow paths 60B extending from the heat source regions SR1, SR2, and SR3, respectively. The arrangement of the independent liquid flow path 60D makes it easier to collect the working fluid 2b within the surface of the wick sheet 30.

[0232] 33, a first heat source region SR1, a second heat source region SR2, and a third heat source region SR3 are arranged on a wick sheet 30. In this case, any two of the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 are connected to each other by a connecting steam passage 51F and a connecting liquid passage 60A, respectively.

[0233] That is, the first heat source region SR1 and the second heat source region SR2 are connected to each other by a connecting steam passage 51F and a connecting liquid flow path 60A. A branch steam passage 51H is connected to the middle of some of the connecting steam passages 51F. The connecting steam passage 51F and the connecting liquid flow path 60A connecting the first heat source region SR1 and the second heat source region SR2 each have a curved portion R that is curved in a curved shape in a plan view.

[0234] The second heat source region SR2 and the third heat source region SR3 are connected to each other by a connecting steam passage 51F and a connecting liquid flow path 60A. A branch steam passage 51H is connected to the middle of some of the connecting steam passages 51F. The connecting steam passage 51F and the connecting liquid flow path 60A connecting the second heat source region SR2 and the third heat source region SR3 each have a curved portion R that is curved in a curved shape in a plan view.

[0235] The third heat source region SR3 and the first heat source region SR1 are connected to each other by a connecting vapor passage 51F and a connecting liquid passage 60A. A branch vapor passage 51H is connected to one of the connecting vapor passages 51F. The connecting liquid passage 60A connecting the third heat source region SR3 and the first heat source region SR1 is connected to another connecting liquid passage 60A connecting the first heat source region SR1 and the second heat source region SR2 at a connection point 67. In this case, the connection point 67 is located within the first heat source region SR1, but may be located outside the first heat source region SR1. The connecting liquid passage 60A connecting the first heat source region SR1 and the second heat source region SR2 is also connected to the connecting liquid passage 60A connecting the third heat source region SR3 and the first heat source region SR1. In addition, the connecting liquid flow path 60A connecting the second heat source region SR2 and the third heat source region SR3 may be connected to the connecting liquid flow path 60A connecting the third heat source region SR3 and the first heat source region SR1.

[0236] An independent vapor passage 51G is connected to each of the heat source regions SR2 and SR3. An independent liquid flow path 60B is connected to each of the heat source regions SR2 and SR3. An independent liquid flow path 60D is arranged adjacent to the branch vapor passage 51H. The independent liquid flow path 60D extends parallel to the independent liquid flow paths 60B extending from each of the heat source regions SR2 and SR3. The arrangement of the independent liquid flow path 60D makes it easier to collect the working fluid 2b within the surface of the wick sheet 30.

[0237] According to this modification, any two of the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 are connected to each other by a connecting vapor passage 51F and a connecting liquid passage 60A. This allows the working vapor 2a to be transported to the inactive device regardless of which of the three devices D1-D3 is in operation. This allows a wide area within the surface of the vapor chamber 1 to be used for heat transport, allowing heat from the heat source to be distributed uniformly within the surface of the vapor chamber 1. Note that any two of the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 need not be connected to each other by at least one connecting vapor passage 51F, but may not be connected to each other by a connecting liquid passage 60A. Furthermore, any two of the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 may be connected to each other by at least one connecting liquid flow path 60A, and may not be connected to each other by a connecting steam passage 51F.

[0238] 34, a first heat source region SR1, a second heat source region SR2, and a third heat source region SR3 are arranged on a wick sheet 30. In this case, any two heat source regions among the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 are connected to each other by a connecting steam passage 51F and a connecting liquid passage 60A, respectively.

[0239] That is, the first heat source region SR1 and the second heat source region SR2 are connected to each other by a connecting steam passage 51F and a connecting liquid flow path 60A. A branch steam passage 51H1 is connected to the middle of one of the connecting steam passages 51F, and a branch steam passage 51H2 is connected to the middle of the other connecting steam passage 51F. The second heat source region SR2 and the third heat source region SR3 are connected to each other by the connecting steam passage 51F and a connecting liquid flow path 60A. The branch steam passage 51H1 is connected to the middle of one of the connecting steam passages 51F, and a branch steam passage 51H2 is connected to the middle of the other connecting steam passage 51F. The third heat source region SR3 and the first heat source region SR1 are connected to each other by the connecting steam passage 51F and a connecting liquid flow path 60A. A branch steam passage 51H1 is connected midway through one of the connecting steam passages 51F, and a branch steam passage 51H2 is connected midway through the other connecting steam passage 51F.

[0240] 34, of the branch steam passages 51H1, 51H2, one branch steam passage 51H1 extends toward the outside in the plane direction of the wick sheet 30, and the other branch steam passage 51H2 extends toward the inside in the plane direction of the wick sheet 30. This allows the working steam 2a from the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 to be transported over a wide area within the plane of the vapor chamber 1, and allows the heat from the heat sources to be distributed uniformly within the plane of the vapor chamber 1. Note that both branch steam passages 51H1, 51H2 may be connected to one connecting steam passage 51F.

[0241] In the first heat source region SR1, the connecting steam passage 51F and the connecting liquid passage 60A connecting the third heat source region SR3 and the first heat source region SR1 are connected to the connecting steam passage 51F and the connecting liquid passage 60A connecting the first heat source region SR1 and the second heat source region SR2, respectively. In the second heat source region SR2, the connecting steam passage 51F and the connecting liquid passage 60A connecting the first heat source region SR1 and the second heat source region SR2 are connected to the connecting steam passage 51F and the connecting liquid passage 60A connecting the second heat source region SR2 and the third heat source region SR3, respectively. Furthermore, within the third heat source region SR3, the connecting steam passage 51F and connecting liquid flow path 60A connecting the second heat source region SR2 and the third heat source region SR3 are respectively connected to the connecting steam passage 51F and connecting liquid flow path 60A connecting the third heat source region SR3 and the first heat source region SR1.

[0242] An independent vapor passage 51G is connected to each of the heat source regions SR1, SR2, and SR3. An independent liquid flow path 60B is connected to each of the heat source regions SR1, SR2, and SR3. An independent liquid flow path 60D is arranged along the independent liquid flow path 60B located on the inner side of the wick sheet 30 in the planar direction. The arrangement of the independent liquid flow path 60D makes it easy to collect the working fluid 2b within the plane of the wick sheet 30.

[0243] The wick sheet 30 may have a planar shape corresponding to the shape of each heat source region SR1, SR2, and SR3. For example, it may have a substantially triangular shape in plan view (equilateral triangle with rounded corners in FIG. 34 ). The centers of the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 may be located at positions corresponding to the vertices of a triangle. The wick sheet 30 is not limited to a triangular shape and may have any shape, such as a rectangular, circular, elliptical, L-shaped, T-shaped, or U-shaped. The connecting vapor passage 51F, the individual vapor passage 51G, the branch vapor passages 51H1 and 51H2, the connecting liquid flow path 60A, the individual liquid flow path 60B, and / or the independent liquid flow path 60D shown in FIG. 34 may be arranged on a wick sheet 30 of any shape.

[0244] According to this modification, any two of the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 are connected to each other by a connecting vapor passage 51F and a connecting liquid passage 60A. This allows the working vapor 2a to be transported to the inactive device regardless of which of the three devices D1-D3 is in operation. This allows a wide area within the vapor chamber 1 to be used for heat transport, allowing the heat from the heat source to be distributed uniformly within the vapor chamber 1.

[0245] 35, a first heat source region SR1, a second heat source region SR2, and a third heat source region SR3 are arranged on a wick sheet 30. In this case, any two of the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 are connected to each other by a connecting steam passage 51F and a connecting liquid passage 60A, respectively.

[0246] That is, the first heat source region SR1 and the second heat source region SR2 are connected to each other by a connecting steam passage 51F and a connecting liquid flow path 60A. A plurality of branch steam passages 51H1 are connected to one of the connecting steam passages 51F, and a plurality of branch steam passages 51H2 are connected to the other connecting steam passage 51F. The second heat source region SR2 and the third heat source region SR3 are connected to each other by the connecting steam passage 51F and a connecting liquid flow path 60A. A plurality of branch steam passages 51H1 are connected to one of the connecting steam passages 51F, and a plurality of branch steam passages 51H2 are connected to the other connecting steam passage 51F. The third heat source region SR3 and the first heat source region SR1 are connected to each other by the connecting steam passage 51F and a connecting liquid flow path 60A. A plurality of branch steam passages 51H1 are connected to one of the connecting steam passages 51F, and a plurality of branch steam passages 51H2 are connected to the other connecting steam passage 51F.

[0247] 35 , of the branch steam passages 51H1, 51H2, one branch steam passage 51H1 extends toward the outside in the planar direction of the wick sheet 30, and the other branch steam passage 51H2 extends toward the inside in the planar direction of the wick sheet 30. This allows the working steam 2a from the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 to be transported over a wide area within the planar direction of the vapor chamber 1, and allows the heat from the heat sources to be distributed uniformly within the planar direction of the vapor chamber 1. Note that both branch steam passages 51H1, 51H2 may be connected to one connecting steam passage 51F.

[0248] An independent vapor passage 51G is connected to each of the heat source regions SR1, SR2, and SR3. An independent liquid flow path 60B is connected to each of the heat source regions SR1, SR2, and SR3. Independent liquid flow paths 60D are arranged adjacent to the branch vapor passages 51H1 and 51H2. The independent liquid flow paths 60D extend parallel to the independent liquid flow paths 60B extending from each of the heat source regions SR1, SR2, and SR3. The arrangement of the independent liquid flow paths 60D makes it easier to collect the working fluid 2b within the surface of the wick sheet 30.

[0249] The wick sheet 30 may have a planar shape corresponding to the shape of each heat source region SR1, SR2, and SR3. For example, it may have a substantially triangular shape in plan view (equilateral triangle with rounded corners in FIG. 35 ). The centers of the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 may be located at the vertices of a triangle. The wick sheet 30 is not limited to a triangular shape and may have any shape, such as a rectangular, circular, elliptical, L-shaped, T-shaped, or U-shaped. The connecting vapor passage 51F, the individual vapor passage 51G, the branch vapor passages 51H1 and 51H2, the connecting liquid flow path 60A, the individual liquid flow path 60B, and / or the independent liquid flow path 60D shown in FIG. 35 may be arranged on a wick sheet 30 of any shape.

[0250] According to this modification, any two of the first heat source region SR1, the second heat source region SR2, and the third heat source region SR3 are connected to each other by a connecting vapor passage 51F and a connecting liquid passage 60A. This allows the working vapor 2a to be transported to the inactive device regardless of which of the three devices D1-D3 is in operation. This allows a wide area within the vapor chamber 1 to be used for heat transport, allowing the heat from the heat source to be distributed uniformly within the vapor chamber 1.

[0251] (Vapor Chamber Modifications) Next, various vapor chamber modifications will be described with reference to Figures 36(a)-(c). Figures 36(a)-(c) are cross-sectional views showing vapor chambers 1 according to respective modifications. In Figures 36(a)-(c), the same parts as those shown in Figures 19 to 35 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0252] As shown in FIG. 36( a), a liquid storage section 70B, which primarily stores the working fluid 2b, may be provided on the first main body surface 31a of the wick sheet 30. This liquid storage section 70B is connected to the vapor flow path section 50 and to the liquid flow path section 60 via the vapor flow path section 50. The liquid storage section 70B may be located in the heat source regions SR1 and SR2 in a plan view. This allows the working fluid 2b to be stored not only in the liquid flow path section 60 but also in the liquid storage section 70B while the devices D1 and D2 are not generating heat. Therefore, even if the working fluid 2b in the liquid flow path section 60 freezes and expands in a temperature environment below the freezing point of the working fluid 2b, the expansion force acting on the upper sheet 20 and the lower sheet 10 can be reduced, preventing deformation of the upper sheet 20 and the lower sheet 10. As a result, deformation of the vapor chamber 1 and a decrease in performance of the vapor chamber 1 can be suppressed.

[0253] 36(b) and 36(c), the vapor chamber 1 may be configured with two layers of sheets. That is, the vapor chamber 1 includes a wick sheet 30 and an upper sheet (sheet) 20 laminated on the wick sheet 30. The vapor passages 51 of the wick sheet 30 are formed in a concave shape on the first main body surface 31a side of the wick sheet 30, and are formed in a groove shape without penetrating the wick sheet 30.

[0254] 36(b) and 36(c), the upper sheet 20 has an upper steam flow path recess 25 provided on the first upper sheet surface 20a. The upper steam flow path recess 25 is formed in a concave shape on the first upper sheet surface 20a side of the upper sheet 20, and is formed in a groove shape without penetrating the upper sheet 20. The upper steam flow path recess 25 is integrated with the steam passages 51 of the wick sheet 30 to form the steam flow path portion 50.

[0255] In Figure 36(c), the upper sheet 20 has an upper liquid flow path recess 26 provided on the first upper sheet surface 20a. The upper liquid flow path recess 26 is formed in a concave shape on the first upper sheet surface 20a side of the upper sheet 20, and is formed in a groove shape without penetrating the upper sheet 20. The upper liquid flow path recess 26, together with the liquid flow path main groove 61 and the liquid flow path communication groove 65 of the wick sheet 30, form the liquid flow path section 60. Note that in Figure 36(b), the upper liquid flow path recess 26 is not provided, and the liquid flow path section 60 exists only in the wick sheet 30.

[0256] Alternatively, although not shown, the vapor chamber 1 may be any member having a vapor passage and a liquid flow path portion, and may be composed of four or more layers of sheet-like members, and does not have to be composed of multiple sheet-like members stacked together.

[0257] 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 penetrating the first main body surface and the second main body surface is formed between the frame portion and the land portion, or between the plurality of land portions, through which the vapor 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 first body surface side flow path communicating with the steam passage is formed in a connection region on the first body surface side of the land portion where the extension direction end of the steam passage contacts in the extension direction of the steam passage.

2. The wick sheet according to claim 1 , wherein another steam passage is present on the opposite side of the connection region to the side where the ends of the steam passages in the extension direction contact each other.

3. The wick sheet according to claim 1 , wherein an evaporation area in which a heat source is arranged is present on the wick sheet, and the first main body surface side flow path is formed continuously along the land portion to the evaporation area.

4. The wick sheet according to claim 1 , wherein the first main body surface side flow passage is also formed in another land portion extending along the vapor passage.

5. The wick sheet according to claim 1 , wherein in a connection region where ends of the steam passages in the extension direction are in contact with each other, the land portion and the steam passage intersect at a non-right angle in a plan view.

6. The wick sheet of claim 1 , wherein the connection region is located at a portion where the land portion curves.

7. The wick sheet according to claim 1 , wherein at least two of the plurality of land portions join together, and an end portion in the extension direction of the vapor passage contacts the land portion at the joining portion.

8. The wick sheet according to claim 1 , wherein the steam passage and the land portion are perpendicular to each other in a plan view at a position where an end portion in an extension direction of the steam passage contacts the land portion.

9. The wick sheet according to claim 1 , wherein the connection region is thinned from the first main body surface side.

10. 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 through space penetrating the first main body surface and the second main body surface is formed between the frame portion and the land portion or between the plurality of land portions; A second body surface groove communicating with the through space is formed on the second body surface side of at least one of the land portions, A wick sheet, wherein an extension direction end of the through space contacts at least one of the plurality of land portions in the extension direction of the through space, and a first body surface side groove communicating with the through space is formed in a connection region on the first body surface side of the land portion where the extension direction end of the through space contacts in the extension direction of the through space.

11. A vapor chamber containing a working fluid, A first sheet; A second sheet; A vapor chamber comprising: a wick sheet according to any one of claims 1 to 10 interposed between the first sheet and the second sheet.

12. Housing and a device contained within the housing; and 12. An electronic device comprising: a vapor chamber according to claim 11 in thermal contact with the device.