Main sheet for vapor chamber, vapor chamber and electronic equipment

Abstract

The present invention aims to provide a main body sheet for a vapor chamber, a vapor chamber, and electronic equipment that can improve cooling efficiency. [Solution] The main body sheet 30 for the vapor chamber according to the present invention comprises a first main body surface 30a, a second main body surface 30b provided on the opposite side of the first main body surface 30a, and a through space extending from the first main body surface 30a to the second main body surface 30b. The through space extends in a first direction in plan view. When viewed in a cross section perpendicular to the first direction, the through space has a first opening 55 located on the first main body surface and a second opening 56 located on the second main body surface. The second opening 56 extends from a region overlapping the first opening 55 in plan view to a position overlapping the first groove 61 in plan view.

Description

Technical Field

[0001] The present invention relates to a main body sheet for a vapor chamber, a vapor chamber, and an electronic device.

Background Art

[0002] In electronic devices such as mobile terminals including mobile terminals such as mobile phones or tablet terminals, electronic devices that generate heat are used. Examples of such electronic devices include a central processing unit (CPU), a light-emitting diode (LED), and a power semiconductor. Such electronic devices are cooled by a heat dissipation device such as a heat pipe (see, for example, Patent Documents 1 and 2). In recent years, due to the thinning of electronic devices, the thinning of heat dissipation devices has also been required. As a heat dissipation device, the development of a vapor chamber that can be made thinner than a heat pipe has been promoted. A vapor chamber efficiently cools an electronic device by an enclosed working fluid absorbing the heat of the electronic device and diffusing inside.

[0003] More specifically, the working fluid (working fluid) in the vapor chamber receives heat from the electronic device in a portion (evaporation portion) close to the electronic device. The working fluid that has received heat evaporates and becomes working vapor. The working vapor diffuses in the vapor flow path portion formed in the vapor chamber in a direction away from the evaporation portion. The diffused working vapor is cooled and condensed to become a working fluid. In the vapor chamber, a liquid flow path portion as a capillary structure (wick) is provided. The working fluid flows through the liquid flow path portion and is transported toward the evaporation portion. The working fluid transported to the evaporation portion receives heat again at the evaporation portion and evaporates. In this way, the working fluid refluxes in the vapor chamber while repeating phase changes, that is, evaporation and condensation, and diffuses the heat of the electronic device. As a result, the heat dissipation efficiency of the vapor chamber is enhanced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] The present invention aims to provide a main body sheet for a vapor chamber, a vapor chamber, and electronic equipment that can improve cooling efficiency. [Means for solving the problem]

[0006] As a first solution, the present invention provides A main body sheet for a vapor chamber in which a working fluid is sealed, The first main surface and A second main body surface is provided on the opposite side from the first main body surface, A through space extending from the first main body surface to the second main body surface, A plurality of first grooves provided on the first main body surface and communicating with the through space, comprising a plurality of first grooves extending in a first direction, The aforementioned through space extends in a first direction in a plan view, When viewed in a cross section perpendicular to the first direction, the through space has a first opening located on the first body surface and a second opening located on the second body surface, the second opening extending from a region overlapping the first opening in a plan view to a position overlapping the first groove in a plan view, the body sheet for the vapor chamber, To provide.

[0007] Furthermore, in the main body sheet for the vapor chamber according to the first solution described above, When viewed in a cross section perpendicular to the first direction, the through space has a first spatial recess provided on the first main body surface that defines the first opening, and a second spatial recess provided on the second main body surface that defines the second opening and communicates with the first spatial recess, The first spatial recess includes a pair of first wall surfaces that are curved in a concave shape, The second spatial recess includes a pair of second wall surfaces that are curved in a concave shape. The first and second wall surfaces, which correspond to each other, are connected by wall projections that protrude toward the inside of the through space. When viewed in a cross-section perpendicular to the first direction, the second spatial recess includes a flat surface formed to connect the corresponding second wall surface and the wall surface projection. You may do so.

[0008] Furthermore, in the main body sheet for the vapor chamber according to the first solution described above, When viewed in a cross section perpendicular to the first direction, the through space has a first spatial recess provided on the first main body surface that defines the first opening, and a second spatial recess provided on the second main body surface that defines the second opening and communicates with the first spatial recess, The first spatial recess includes a pair of first wall surfaces that are curved in a concave shape, The second spatial recess includes a pair of second wall surfaces that are curved in a concave shape. The first and second wall surfaces, which correspond to each other, are connected by wall projections that protrude toward the inside of the through space. When viewed in a cross section perpendicular to the first direction, the second spatial recess includes a convex surface connecting the corresponding second wall surface and the wall surface projection, The convex surface includes a spatial convex portion that extends in the first direction and protrudes toward the second main body surface. You may do so.

[0009] Furthermore, in the main body sheet for the vapor chamber according to the first solution described above, The convex surface includes a plurality of spatially spaced convex portions, You may do so.

[0010] Furthermore, in the main body sheet for the vapor chamber according to the first solution described above, When viewed in a cross-section perpendicular to the first direction, the through-space has a first space recess that defines the first opening and is provided on the first main body surface, and a second space recess that defines the second opening and is provided on the second main body surface. The second space recess communicates with the first space recess. The first space recess includes a pair of first wall surfaces that are convexly curved. The second space recess includes a pair of second wall surfaces that are concavely curved. It may be like this.

[0011] Also, in the main body sheet for a vapor chamber according to the first solution means described above, When viewed in a cross-section perpendicular to the first direction, the second opening extends from a region that overlaps the first opening in a plan view to positions on both sides of the first opening up to positions that overlap the first groove in a plan view. It may be like this.

[0012] Also, in the main body sheet for a vapor chamber according to the first solution means described above, A frame portion that is formed in a frame shape in a plan view and extends from the first main body surface to the second main body surface, and defines the through-space. A land portion provided inside the frame portion, which extends in the first direction and from the first main body surface to the second main body surface. The first opening and the second opening are located between the frame portion and the land portion. The first groove is located on the first main body surface of the land portion. When viewed in a cross-section perpendicular to the first direction, the second opening extends from a region that overlaps the first opening in a plan view to a position that overlaps the first groove located in the land portion in a plan view, and also extends toward the outside of the frame portion from the first opening. It may be like this.

[0013] Also, as a second solution means, the present invention provides A main body sheet for a vapor chamber in which a working fluid is enclosed. a first main body surface, a second main body surface provided on the side opposite to the first main body surface, and a through space extending from the first main body surface to the second main body surface, wherein the through space extends in a first direction in a plan view, when viewed in a cross section perpendicular to the first direction, the through space has a first space recess provided on the first main body surface and a second space recess provided on the second main body surface and communicating with the first space recess, the first space recess includes a pair of first wall surfaces, the second space recess includes a pair of second wall surfaces, one of the first wall surfaces of the first space recess and the corresponding second wall surface of the second space recess are connected by a first wall surface protrusion, the first wall surface protrusion protrudes toward the inside of the through space, the first wall surface protrusion is displaced with respect to an intermediate position between the first main body surface and the second main body surface in the normal direction of the first main body surface, the first wall surface located on the side opposite to the first wall surface protrusion of the first space recess and the corresponding second wall surface of the second space recess are continuously formed in a concave shape from the first wall surface to the second wall surface, a main body sheet for a vapor chamber, is provided.

[0014] In addition, in the main body sheet for a vapor chamber according to the second solution means described above, the through space has a first opening defined by the first space recess located on the first main body surface and a second opening defined by the second space recess located on the second main body surface, when viewed in a cross section perpendicular to the first direction, the center of the first opening is displaced with respect to the center of the second opening, may be such.

[0015] Further, as a third solution means, the present invention provides a main body sheet for a vapor chamber in which a working fluid is enclosed, The first main surface and A second main body surface is provided on the opposite side from the first main body surface, It comprises a through space extending from the first main body surface to the second main body surface, The aforementioned through space extends in a first direction in a plan view, When viewed in a cross section perpendicular to the first direction, the through space has a first spatial recess provided on the first main body surface and a second spatial recess provided on the second main body surface that communicates with the first spatial recess. The first spatial recess includes a pair of first wall surfaces, The second spatial recess includes a pair of second wall surfaces, One of the first wall surfaces of the first spatial recess and the corresponding second wall surface of the second spatial recess are connected by a protruding first wall surface. The first wall projection protrudes toward the inside of the through space, The first wall projection is positioned offset from the intermediate position between the first and second main body surfaces in the direction normal to the first main body surface. The through space has a first opening located on the first main body surface and defined by the first spatial recess, and a second opening located on the second main body surface and defined by the second spatial recess. When viewed in a cross section perpendicular to the first direction, the center of the first opening is offset from the center of the second opening, the main sheet for the vapor chamber To provide.

[0016] Furthermore, in the main body sheet for the vapor chamber according to the third solution described above, A frame-shaped section formed in a plan view, The frame portion is further provided with a land portion that extends in the first direction and defines the through space between itself and the frame portion, When the width of the land portion is w1, the displacement between the center of the first opening and the center of the second opening is 0.05 mm to (0.8 × w1) mm. You may do so.

[0017] Furthermore, in the main body sheet for the vapor chamber according to the third solution described above, The first main body surface is further provided with a plurality of first grooves that communicate with the through space, The first wall projection is positioned closer to the first main body surface than the intermediate position. You may do so.

[0018] Furthermore, in the main body sheet for the vapor chamber according to the third solution described above, The first wall surface located on the opposite side of the first wall surface projection of the first spatial recess and the corresponding second wall surface of the second spatial recess are connected by the second wall surface projection. The second wall projection protrudes toward the inside of the through space, The second wall projection is positioned offset in the normal direction from the intermediate position between the first main body surface and the second main body surface. You may do so.

[0019] Furthermore, in the main body sheet for the vapor chamber according to the third solution described above, The second wall projection is positioned closer to the first main body surface than the intermediate position. You may do so.

[0020] Furthermore, the present invention provides a fourth solution, A main body sheet for a vapor chamber in which a working fluid is sealed, The first main surface and A second main body surface is provided on the opposite side from the first main body surface, It comprises a through space extending from the first main body surface to the second main body surface, The aforementioned through space extends in a first direction in a plan view, When viewed in a cross section perpendicular to the first direction, the through space comprises a first spatial recess provided on the first main body surface, a second spatial recess provided on the second main body surface that communicates with the first spatial recess, and a third spatial recess provided on the second main body surface, located on both sides of the second spatial recess and communicating with the second spatial recess. The second spatial recess includes a pair of second wall surfaces, The third spatial recess includes a third wall surface, Each of the second wall surfaces of the second spatial recess and the corresponding third wall surface of the third spatial recess are connected by a third wall surface projection. The third wall projection protrudes toward the second main body surface, the main body sheet for the vapor chamber, To provide.

[0021] Furthermore, in the main body sheet for the vapor chamber according to the fourth solution described above, The first spatial recess includes a pair of first wall surfaces, One of the first wall surfaces of the first spatial recess and the corresponding second wall surface of the second spatial recess are connected by a protruding first wall surface. The first wall projection protrudes toward the inside of the through space, The first wall projection is positioned offset from the intermediate position between the first and second main body surfaces in the direction normal to the first main body surface. You may do so.

[0022] Furthermore, in the main body sheet for the vapor chamber according to the fourth solution described above, The first main body surface is further provided with a plurality of first grooves that communicate with the through space, The first wall projection is positioned closer to the first main body surface than the intermediate position. You may do so.

[0023] Furthermore, in the main body sheet for the vapor chamber according to the fourth solution described above, The first wall surface located on the opposite side of the first wall surface projection of the first spatial recess and the corresponding second wall surface of the second spatial recess are connected by the second wall surface projection. The second wall projection protrudes toward the inside of the through space, The second wall projection is positioned offset in the normal direction from the intermediate position between the first main body surface and the second main body surface. You may do so.

[0024] Furthermore, in the main body sheet for the vapor chamber according to the fourth solution described above, The second wall projection is positioned closer to the first main body surface than the intermediate position. You may do so.

[0025] Furthermore, in the main body sheet for the vapor chamber according to the fourth solution described above, The first wall surface located on the opposite side of the first wall surface projection of the first spatial recess and the corresponding second wall surface of the second spatial recess are formed in a continuous concave shape from the first wall surface to the second wall surface. You may do so.

[0026] Furthermore, in the main body sheet for the vapor chamber according to the fourth solution described above, The through space has a first opening located on the first main body surface and defined by the first spatial recess, and a second opening located on the second main body surface and defined by the second spatial recess. When viewed in a cross-section perpendicular to the first direction, the center of the first opening is offset from the center of the second opening. You may do so.

[0027] Furthermore, in the main body sheet for the vapor chamber according to the fourth solution described above, A frame-shaped section formed in a plan view, The frame portion is further provided with a land portion that extends in the first direction and defines the through space between itself and the frame portion, When the width of the land portion is w1, the displacement between the center of the first opening and the center of the second opening is 0.05 mm to (0.8 × w1) mm. You may do so.

[0028] Furthermore, the present invention provides a fifth solution, This is a main sheet for a vapor chamber, The first main surface and A second main body surface located on the opposite side from the first main body surface, A through space that penetrates the first main body surface and the second main body surface, The second main body surface is provided with a plurality of first grooves that communicate with the through space, The through space has a curved first wall surface located on the side of the first main body surface and a curved second wall surface located on the side of the second main body surface. The first wall surface and the second wall surface meet at a projection formed to protrude inward into the through space, The projection is located closer to the second body surface than an intermediate position between the first body surface and the second body surface. The first wall surface has a first wall surface end on the side of the first main body surface, The first wall end is located inward of the through-space than the projection in a plan view, and is the main sheet for the vapor chamber. To provide.

[0029] Furthermore, in the main body sheet for the vapor chamber according to the fifth solution described above, The second wall surface has a second wall surface end on the side of the second main body surface, When Lp is the distance between the second wall end and the projection in the width direction of the through space, and Ls is the distance between the second wall end and the first wall end, the distance Ls is 1.05 times or more and 2 times or less of the distance Lp. You may do so.

[0030] Furthermore, in the main body sheet for the vapor chamber according to the fifth solution described above, The multiple first grooves are arranged in parallel to each other, A row of protrusions is provided between the adjacent first grooves, Each of the aforementioned rows of protrusions has multiple protrusions, The second wall surface has a second wall surface end on the side of the second main body surface, When the distance between the second wall end and the first wall end is Ls, the distance Ls is between 1.1 and 10 times the width of the protrusion. You may do so.

[0031] Furthermore, the present invention provides a sixth solution, The first sheet and, The second seat and, A vapor chamber comprising a main sheet for a vapor chamber, each of the first to sixth solutions, interposed between the first and second sheets, To provide.

[0032] Furthermore, the present invention provides a seventh solution, A vapor chamber in which a working fluid is sealed, The first sheet and, The second seat and, It comprises a main sheet for a vapor chamber interposed between the first sheet and the second sheet, The aforementioned main sheet is The first main surface and A second main body surface located on the opposite side from the first main body surface, A through space that penetrates the first main body surface and the second main body surface, The second main body surface is provided with a plurality of first grooves that communicate with the through space, The through space has a curved first wall surface located on the side of the first main body surface and a curved second wall surface located on the side of the second main body surface. The first wall surface and the second wall surface meet at a projection formed to protrude inward into the through space, The projection is located closer to the second body surface than an intermediate position between the first body surface and the second body surface. The first wall surface has a first wall surface end on the side of the first main body surface, The first wall end is located inward of the projection in the through space in a plan view, and is a vapor chamber. To provide.

[0033] Furthermore, in the vapor chamber according to the seventh solution described above, The second wall surface has a second wall surface end on the side of the second main body surface, When Lp is the distance between the second wall end and the projection in the width direction of the through space, and Ls is the distance between the second wall end and the first wall end, the distance Ls is 1.05 times or more and 2 times or less of the distance Lp. You may do so.

[0034] Furthermore, in the vapor chamber according to the seventh solution described above, The multiple first grooves are arranged in parallel to each other, A row of protrusions is provided between the adjacent first grooves, Each of the aforementioned rows of protrusions has multiple protrusions, The second wall surface has a second wall surface end on the side of the second main body surface, When the distance between the second wall end and the first wall end is Ls, the distance Ls is between 1.1 and 10 times the width of the protrusion. You may do so.

[0035] Furthermore, the present invention provides an eighth solution, Housing and The electronic device housed within the aforementioned housing, An electronic device comprising a vapor chamber provided by a sixth or seventh solution that is thermally in contact with the aforementioned electronic device, To provide. [Effects of the Invention]

[0036] According to the present invention, cooling efficiency can be improved. [Brief explanation of the drawing]

[0037] [Figure 1] Figure 1 is a schematic perspective view illustrating an electronic device according to a first embodiment of the present invention. [Figure 2] Figure 2 is a top view showing a vapor chamber according to a first embodiment of the present invention. [Figure 3] Figure 3 is a cross-sectional view along line AA showing the vapor chamber in Figure 2. [Figure 4] Figure 4 is a top view of the lower sheet shown in Figure 3. [Figure 5] Figure 5 is a bottom view of the upper sheet shown in Figure 3. [Figure 6] Figure 6 is a top view of the wick sheet shown in Figure 3. [Figure 7] Figure 7 is a bottom view of the wick sheet shown in Figure 3. [Figure 8A] Figure 8A is a partially enlarged cross-sectional view of Figure 3 showing the second steam passage. [Figure 8B] Figure 8B is a partially enlarged cross-sectional view showing an example of an upper opening. [Figure 8C] Figure 8C is a partially enlarged cross-sectional view showing an example of an upper opening. [Figure 8D] Figure 8D is a partially enlarged cross-sectional view showing an example of an upper opening. [Figure 8E] Figure 8E is a partially enlarged cross-sectional view showing an example of an upper opening. [Figure 8F] Figure 8F is a schematic diagram illustrating a flat surface. [Figure 9] Figure 9 is a partially enlarged top view of the liquid flow channel shown in Figure 7. [Figure 10] Figure 10 is a partially enlarged cross-sectional view of Figure 3 showing the first steam passage. [Figure 11] Figure 11 is a partially enlarged cross-sectional view showing a modified example of the vapor chamber shown in Figure 8A. [Figure 12] Figure 12 is a partially enlarged cross-sectional view showing a modified example of the vapor chamber shown in Figure 8A. [Figure 13] Figure 13 is a partially enlarged cross-sectional view showing a modified example of the vapor chamber shown in Figure 8A. [Figure 14] Figure 14 is a partially enlarged cross-sectional view showing a modified example of the vapor chamber shown in Figure 8A. [Figure 15A] Figure 15A is a modified example of the wick sheet shown in Figure 6, and is a partially enlarged top view of Figure 6. [Figure 15B] Figure 15B is a partially enlarged cross-sectional view showing the second steam passage in the second region shown in Figure 15A. [Figure 16] Figure 16 is a cross-sectional view showing a vapor chamber according to a second embodiment of the present invention, and is a cross-sectional view corresponding to the cross-section along line AA in Figure 2. [Figure 17] Figure 17 is a partially enlarged cross-sectional view of Figure 16. [Figure 18] Figure 18 is a diagram illustrating the preparation step of the wick sheet in the method for manufacturing a vapor chamber according to the second embodiment. [Figure 19] Figure 19 is a diagram illustrating the resist formation process in the method for manufacturing a vapor chamber according to the second embodiment. [Figure 20] Figure 20 is a diagram illustrating the resist patterning process in the method for manufacturing a vapor chamber according to the second embodiment. [Figure 21] Figure 21 is a diagram illustrating the etching process in the method for manufacturing a vapor chamber according to the second embodiment. [Figure 22] Figure 22 is a diagram illustrating the resist removal step in the method for manufacturing a vapor chamber according to the second embodiment. [Figure 23] Figure 23 is a diagram illustrating the joining process of the manufacturing method for a vapor chamber according to the second embodiment. [Figure 24] Figure 24 is a partially enlarged cross-sectional view showing a modified example of the vapor chamber shown in Figure 17. [Figure 25]Figure 25 is a partially enlarged cross-sectional view showing another modification of the vapor chamber shown in Figure 17. [Figure 26] Figure 26 is a partially enlarged cross-sectional view showing a vapor chamber in a third embodiment of the present invention. [Figure 27] Figure 27 is a diagram illustrating the first resist formation step in the manufacturing method of a vapor chamber according to the third embodiment. [Figure 28] Figure 28 is a diagram illustrating the first patterning step of the first resist in the method for manufacturing a vapor chamber according to the third embodiment. [Figure 29] Figure 29 is a diagram illustrating the first etching step in the manufacturing method of a vapor chamber according to the third embodiment. [Figure 30] Figure 30 is a diagram illustrating the first resist removal step in the method for manufacturing a vapor chamber according to the third embodiment. [Figure 31] Figure 31 is a diagram illustrating the second resist formation step in the method for manufacturing a vapor chamber according to the third embodiment. [Figure 32] Figure 32 is a diagram illustrating the second patterning step of the second resist in the method for manufacturing a vapor chamber according to the third embodiment. [Figure 33] Figure 33 is a diagram illustrating the second etching step in the manufacturing method of a vapor chamber according to the third embodiment. [Figure 34] Figure 34 is a diagram illustrating the second resist removal step in the manufacturing method of a vapor chamber according to the third embodiment. [Figure 35] Figure 35 is a partially enlarged cross-sectional view showing a modified example of the vapor chamber shown in Figure 26. [Figure 36] Figure 36 is a top view showing a vapor chamber according to a fourth embodiment of the present invention. [Figure 37] Figure 37 is a cross-sectional view along line BB showing the vapor chamber in Figure 36. [Figure 38]Figure 38 is a top view of the lower sheet shown in Figure 37. [Figure 39] Figure 39 is a bottom view of the upper sheet shown in Figure 37. [Figure 40] Figure 40 is a top view of the wick sheet shown in Figure 37. [Figure 41] Figure 41 is a bottom view of the wick sheet shown in Figure 37. [Figure 42] Figure 42 is a partially enlarged cross-sectional view of Figure 37. [Figure 43] Figure 43 is a partially enlarged top view of the liquid flow channel shown in Figure 40. [Figure 44] Figure 44 illustrates a method for manufacturing a vapor chamber according to a fourth embodiment. [Figure 45] Figure 45 illustrates a method for manufacturing a vapor chamber according to the fourth embodiment. [Figure 46] Figure 46 illustrates a method for manufacturing a vapor chamber according to the fourth embodiment. [Figure 47] Figure 47 is a partially enlarged cross-sectional view showing the flow of the working fluid in the steam passage section according to the fourth embodiment. [Modes for carrying out the invention]

[0038] Embodiments of the present invention will be described below with reference to the drawings. Note that, for the sake of illustration and ease of understanding, the scale and aspect ratios of the drawings accompanying this specification have been appropriately altered and exaggerated from those of the actual objects.

[0039] The geometric conditions, physical properties, terms specifying the degree of the geometric conditions or physical properties, and numerical values ​​indicating the geometric conditions or physical properties used herein may be interpreted without being bound by strict meaning. Furthermore, these geometric conditions, physical properties, terms, and numerical values ​​may be interpreted to include a range within which similar functions can be expected. Examples of terms specifying geometric conditions include "length," "angle," "shape," and "arrangement." Examples of terms specifying geometric conditions include "parallel," "orthogonal," and "identical." In addition, for clarity in the drawings, the shapes of multiple parts that can be expected to perform similar functions are regularly depicted. However, the shapes of these parts may differ from each other within the range within which the function can be expected, without being bound by strict meaning. In the drawings, boundary lines indicating joint surfaces between members are shown as simple straight lines for convenience, but they are not required to be strictly straight lines, and the shape of the boundary lines is arbitrary within the range within which the desired joint performance can be expected.

[0040] (First Embodiment) Figures 1 to 15B will be used to describe the main sheet for the vapor chamber, the vapor chamber, and the electronic equipment in the first embodiment of the present invention. In this embodiment, the vapor chamber 1 is housed in the housing H of the electronic equipment E together with an electronic device D that generates heat, and is a device for cooling the electronic device D. Examples of electronic equipment E include mobile terminals such as handheld terminals and tablet terminals. Examples of electronic device D include a central processing unit (CPU), light-emitting diodes (LEDs), and power semiconductors. The electronic device D may also be referred to as the device to be cooled.

[0041] Here, we will first describe the electronic device E equipped with the vapor chamber 1 according to this embodiment, using a tablet terminal as an example. As shown in Figure 1, the electronic device E comprises a housing H, an electronic device D housed within the housing H, and the vapor chamber 1. In the electronic device E shown in Figure 1, a touch panel display TD is provided on the front of the housing H. The vapor chamber 1 is housed within the housing H and positioned to be in thermal contact with the electronic device D. The vapor chamber 1 receives heat generated by the electronic device D when the electronic device E is in use. The heat received by the vapor chamber 1 is released to the outside of the vapor chamber 1 via working fluids 2a and 2b, which will be described later. In this way, the electronic device D is effectively cooled. When the electronic device E is a tablet terminal, the electronic device D may be a central processing unit or the like.

[0042] Next, the vapor chamber 1 according to this embodiment will be described. As shown in Figures 2 and 3, the vapor chamber 1 has a sealed space 3 containing working fluids 2a and 2b. The electronic device D of the electronic device E described above is effectively cooled by the repeated phase changes of the working fluids 2a and 2b in the sealed space 3. Examples of working fluids 2a and 2b include pure water, ethanol, methanol, acetone, and mixtures thereof. The working fluids 2a and 2b may also have freeze-expanding properties. That is, the working fluids 2a and 2b may be fluids that expand when frozen. Examples of working fluids 2a and 2b that have freeze-expanding properties include pure water and aqueous solutions of pure water with additives such as alcohol.

[0043] As shown in Figures 2 and 3, the vapor chamber 1 comprises a lower sheet 10, an upper sheet 20, a wick sheet 30 for the vapor chamber, a vapor flow path section 50, and a liquid flow path section 60. The wick sheet 30 is interposed between the lower sheet 10 and the upper sheet 20. The wick sheet 30 for the vapor chamber will hereinafter be simply referred to as the wick sheet 30. In this embodiment, the vapor chamber 1 has the lower sheet 10, the wick sheet 30, and the upper sheet 20 stacked in this order.

[0044] The vapor chamber 1 is generally formed in the shape of a thin, flat plate. The planar shape of the vapor chamber 1 is arbitrary, but it may be rectangular as shown in Figure 2. The planar shape of the vapor chamber 1 may be, for example, a rectangle with one side of 1 cm and the other side of 3 cm, or a square with one side of 15 cm. The planar dimensions of the vapor chamber 1 are arbitrary. In this embodiment, as an example, an example in which the planar shape of the vapor chamber 1 is rectangular with the X direction as the longitudinal direction, as will be described later, will be explained. In this case, as shown in Figures 4 to 7, the lower sheet 10, the upper sheet 20, and the wick sheet 30 may have the same planar shape as the vapor chamber 1. Furthermore, the planar shape of the vapor chamber 1 is not limited to a rectangular shape, but may be any shape such as a circle, an ellipse, an L-shape, or a T-shape.

[0045] As shown in Figure 2, the vapor chamber 1 has an evaporation region SR where the working fluids 2a and 2b evaporate, and a condensation region CR where the working fluids 2a and 2b condense. Working vapor 2a is a working fluid in a gaseous state, and working liquid 2b is a working fluid in a liquid state.

[0046] The evaporation region SR is the region that overlaps with the electronic device D in a plan view, and is the region where the electronic device D is mounted. The evaporation region SR may 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 Figure 2). Heat from the electronic device D is transferred to the evaporation region SR, and this heat causes the working fluid 2b to evaporate in the evaporation region SR. The heat from the electronic device D can be transferred not only to the region that overlaps with the electronic device D in a plan view, but also to the surrounding area of ​​that region. Therefore, the evaporation region SR includes the region that overlaps with the electronic device D and the surrounding area in a plan view. Here, a plan view may refer to a view of the vapor chamber 1 from a direction perpendicular to the surface that receives heat from the electronic device D and the surface that releases the received heat. The surface that receives heat corresponds to the first lower sheet surface 10a of the lower sheet 10, which will be described later. The surface that releases heat corresponds to the second upper sheet surface 20b of the upper sheet 20, which will be described later. For example, as shown in Figure 2, a view of the vapor chamber 1 from above or from below corresponds to a plan view.

[0047] The condensation region CR is a region that does not overlap with the electronic device D in a plan view, and is primarily a region where the working fluid, working vapor 2a, releases heat and condenses. The condensation region CR may also be the region surrounding the evaporation region SR. In the condensation region CR, heat from the working vapor 2a is released to the upper sheet 20, and the working vapor 2a is cooled and condenses in the condensation region CR.

[0048] Furthermore, when the vapor chamber 1 is installed inside a mobile terminal, the top-bottom relationship may be disrupted depending on the orientation of the mobile terminal. However, for convenience, in this embodiment, the sheet that receives heat from the electronic device D is referred to as the lower sheet 10, and the sheet that releases the received heat is referred to as the upper sheet 20. Therefore, the following explanation will be given with the lower sheet 10 positioned at the bottom and the upper sheet 20 positioned at the top.

[0049] As shown in Figure 3, the lower sheet 10 is an example of a first sheet. 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. The second lower sheet surface 10b is located on the side of the wick sheet 30. In this embodiment, the second lower sheet surface 10b is in contact with the first main body surface 30a of the wick sheet 30, which will be described later. As shown in Figure 4, alignment holes 12 may be provided at the four corners of the lower sheet 10. The above-mentioned electronic device D may be attached to the first lower sheet surface 10a.

[0050] As shown in Figure 3, the upper sheet 20 is an example of a second sheet. The upper sheet 20 has a first upper sheet surface 20a provided on the side of the wick sheet 30, and a second upper sheet surface 20b provided on the opposite side from the first upper sheet surface 20a. In this embodiment, the first upper sheet surface 20a is in contact with the second main body surface 30b of the wick sheet 30, which will be described later. As shown in Figure 5, alignment holes 22 may be provided at the four corners of the upper sheet 20. A housing member Ha, which constitutes a part of the housing H described above, may be attached to the second upper sheet surface 20b. The entire second upper sheet surface 20b may be covered with the housing member Ha.

[0051] As shown in Figure 3, the wick sheet 30 is an example of a main sheet. The wick sheet 30 has a first main surface 30a and a second main surface 30b provided on the opposite side from the first main surface 30a. The first main surface 30a is located on the side of the lower sheet 10, and the lower sheet 10 is provided on the first main surface 30a. The second main surface 30b is located on the side of the upper sheet 20, and the upper sheet 20 is provided on the second main surface 30b.

[0052] The second lower sheet surface 10b of the lower sheet 10 and the first main body surface 30a of the wick sheet 30 may be permanently joined to each other by diffusion bonding. Similarly, the first upper sheet surface 20a of the upper sheet 20 and the second main body surface 30b of the wick sheet 30 may be permanently joined to each other by diffusion bonding. The lower sheet 10, upper sheet 20, and wick sheet 30 may be joined by other methods such as brazing, as long as they can be permanently joined, rather than by diffusion bonding. The term "permanently joined" is not bound by a strict meaning and may be used to mean that the joint between the lower sheet 10 and the wick sheet 30 can be maintained to the extent that the airtightness of the sealed space 3 can be maintained during the operation of the vapor chamber 1. The term "permanently joined" may also be used to mean that the joint between the upper sheet 20 and the wick sheet 30 can be maintained to the extent that it can be joined.

[0053] As shown in Figures 3, 6, and 7, the wick sheet 30 according to this embodiment has a frame portion 32 formed in the shape of a rectangular frame in plan view, and a plurality of land portions 33 provided within the frame portion 32. The frame portion 32 and each land portion 33 extend from the first main body surface 30a to the second main body surface 30b. The frame portion 32 and the land portions 33 are parts where the material of the wick sheet 30 remains without being etched in the etching process described later. In this embodiment, the frame portion 32 is formed in the shape of a rectangular frame in plan view. A steam flow path portion 50 is defined inside the frame portion 32. The steam flow path portion 50 is arranged inside the frame portion 32, around each land portion 33. Working steam 2a flows around each land portion 33. The steam flow path portion 50 is defined between the frame portion 32 and the land portions 33, and also between pairs of adjacent land portions 33.

[0054] In this embodiment, the land portion 33 may extend in an elongated shape with the X direction as the longitudinal direction in a plan view. The planar shape of the land portion 33 may be an elongated rectangular shape. Each land portion 33 may be spaced equally apart in the Y direction and arranged parallel to each other. The working steam 2a flows around each land portion 33 and is transported toward the condensation region CR. This suppresses obstruction of the flow of the working steam 2a. In this embodiment, the X direction is an example of a first direction and corresponds to the left-right direction in Figure 6. The Y direction is an example of a second direction and corresponds to the up-down direction in Figure 6. The X direction is the longitudinal direction of the land portion 33, and the Y direction is the direction perpendicular to the X direction in a plan view. The direction perpendicular to the X direction and the Y direction, respectively, is the Z direction.

[0055] The width w1 of the land portion 33 (see Figure 8A) may be, for example, 100 μm to 3000 μm. Here, the width w1 of the land portion 33 is the dimension of the land portion 33 in the Y direction. To describe in more detail using the wall projections 57 and 58 described later, the width w1 of the land portion 33 means the distance in the Y direction between the tip of the first wall projection 57 that defines the land portion 33 and the tip of the second wall projection 58.

[0056] The frame portion 32 and each land portion 33 are diffusion-bonded to the lower sheet 10 and also to the upper sheet 20. This improves the mechanical strength of the vapor chamber 1. The lower wall surfaces 53a and 53b of the lower steam flow recess 53 and the upper wall surfaces 54a and 54b of the upper steam flow recess 54, which will be described later, constitute the side walls of the land portion 33. The first main body surface 30a and the second main body surface 30b of the wick sheet 30 may be formed flat over the frame portion 32 and each land portion 33.

[0057] The steam passage section 50 is an example of a through-space. The steam passage section 50 may be provided on the first main body surface 30a of the wick sheet 30. The steam passage section 50 may be a passage through which working steam 2a mainly passes. Working fluid 2b may also pass through the steam passage section 50. In this embodiment, the steam passage section 50 extends from the first main body surface 30a to the second main body surface 30b and penetrates the wick sheet 30. The steam passage section 50 may be covered by the lower sheet 10 on the first main body surface 30a, and may be covered by the upper sheet 20 on the second main body surface 30b.

[0058] As shown in Figures 6 and 7, the steam flow section 50 in this embodiment has a first steam passage 51 and a plurality of second steam passages 52. The first steam passage 51 includes a portion extending in the X direction and a portion extending in the Y direction in a plan view, and is formed between the frame portion 32 and the land portion 33. This first steam passage 51 is formed continuously inside the frame portion 32 and outside the land portion 33. The planar shape of the first steam passage 51 is rectangular. The second steam passages 52 extend in the X direction in a plan view and are formed between adjacent land portions 33. The planar shape of the second steam passages 52 is elongated rectangular. The steam flow section 50 is divided into the first steam passage 51 and the plurality of second steam passages 52 by the plurality of land portions 33.

[0059] As shown in Figure 8A, the first steam passage 51 and the second steam passage 52 extend from the first main body surface 30a to the second main body surface 30b of the wick sheet 30. The first steam passage 51 and the second steam passage 52 each have a lower steam passage recess 53, an upper steam passage recess 54, a lower opening 55, and an upper opening 56. The lower steam passage recess 53 is an example of a first space recess and is provided on the first main body surface 30a. The upper steam passage recess 54 is an example of a second space recess and is provided on the second main body surface 30b. By connecting the lower steam passage recess 53 and the upper steam passage recess 54, the first steam passage 51 and the second steam passage 52 of the steam passage section 50 are formed to extend from the first main body surface 30a to the second main body surface 30b. The lower opening 55 is an example of a first opening and is located on the first main body surface 30a. The lower opening 55 is defined on the first main body surface 30a by a lower steam flow channel recess 53. The upper opening 56 is an example of a second opening and is located on the second main body surface 30b. The upper opening 56 is defined on the second main body surface 30b by an upper steam flow channel recess 54.

[0060] The lower steam passage recess 53 is formed in a concave shape on the first main body surface 30a of the wick sheet 30 by etching from the first main body surface 30a in the etching process described later. As a result, the lower steam passage recess 53 has a pair of curved lower wall surfaces 53a and 53b, as shown in Figure 8A. The lower wall surfaces 53a and 53b are examples of first wall surfaces. The lower wall surface 53a is the left wall surface in Figure 8A, and the lower wall surface 53b is the right wall surface in Figure 8A. The lower wall surfaces 53a and 53b are formed to extend from the lower opening 55 toward the second main body surface 30b. The lower wall surfaces 53a and 53b may be curved in a concave shape. Each lower wall surface 53a, 53b defines a lower steam passage recess 53 and, in the cross-section shown in Figure 8A, may curve so as it approaches the second main body surface 30b, it approaches the opposing lower wall surfaces 53a, 53b. Such a lower steam passage recess 53 constitutes a part of the first steam passage 51 and a part of the second steam passage 52. The lower steam passage recess 53 may also constitute the lower half of the first steam passage 51 and the lower half of the second steam passage 52.

[0061] The width w2 of the lower opening 55 may be, for example, 100 μm to 3000 μm. The width w2 of the lower opening 55 represents the width dimension of the lower steam passage recess 53 on the first main body surface 30a. The width w2 corresponds to the dimension in the Y direction in the portion of the first steam passage 51 that extends in the X direction, and also corresponds to the dimension in the Y direction in the second steam passage 52. In this embodiment, the dimension in the Y direction between the lower wall surface 53a and the lower wall surface 53b of the lower steam passage recess 53 gradually increases from the second main body surface 30b toward the first main body surface 30a, and is maximum at the first main body surface 30a. Therefore, the width w2 is the maximum value of the dimension in the Y direction between the lower wall surface 53a and the lower wall surface 53b. However, the dimension in the Y direction between the lower wall surface 53a and the lower wall surface 53b does not have to be maximum at the first main body surface 30a. For example, the position where the Y-direction dimension between the lower wall surface 53a and the lower wall surface 53b is maximum may be located closer to the second main body surface 30b than to the first main body surface 30a. The width w2 also corresponds to the X-direction dimension of the portion of the first steam passage 51 that extends in the Y-direction.

[0062] The upper steam channel recess 54 is formed in a concave shape on the second main body surface 30b of the wick sheet 30 by etching from the second main body surface 30b in the etching process described later. As a result, the upper steam channel recess 54 has a pair of curved upper wall surfaces 54a and 54b, as shown in Figure 8A. The upper wall surfaces 54a and 54b are examples of second wall surfaces. Upper wall surface 54a is the left wall surface in Figure 8A, and upper wall surface 54b is the right wall surface in Figure 8A. Upper wall surfaces 54a and 54b are formed to extend from the upper opening 56 toward the first main body surface 30a. The upper wall surfaces 54a and 54b may be curved in a concave shape. Each upper wall surface 54a, 54b defines an upper steam flow recess 54 and may be curved in the cross-section shown in Figure 8A so as it approaches the first main body surface 30a, it approaches the opposing upper wall surfaces 54a, 54b. Such an upper steam flow recess 54 constitutes a part of the first steam passage 51 and a part of the second steam passage 52. The upper steam flow recess 54 may also constitute the upper half of the first steam passage 51 and the upper half of the second steam passage 52.

[0063] The width w3 of the upper opening 56 may be larger than the width w2 of the lower opening 55 described above. The width w3 may be, for example, 160 μm to 5800 μm. The width w3 of the upper opening 56 represents the width dimension of the upper steam passage recess 54 on the second main body surface 30b. The width w3 corresponds to the Y-direction dimension of the portion of the first steam passage 51 that extends in the X-direction and the Y-direction dimension of the second steam passage 52. In this embodiment, the Y-direction dimension between the upper wall surface 54a and the upper wall surface 54b gradually increases from the first main body surface 30a to the second main body surface 30b, and is maximum at the second main body surface 30b. Therefore, the width w3 is the maximum value of the Y-direction dimension between the upper wall surface 54a and the upper wall surface 54b. However, the Y-direction dimension between the upper wall surface 54a and the upper wall surface 54b does not have to be maximum at the second main body surface 30b. For example, the position where the Y-direction dimension between the upper wall surface 54a and the upper wall surface 54b is maximum may be located closer to the first main body surface 30a than to the second main body surface 30b. The width w3 also corresponds to the X-direction dimension of the portion of the first steam passage 51 that extends in the Y-direction.

[0064] As shown in Figure 8A, in a plan view, the center 55a of the lower opening 55 may coincide with the center 56a of the upper opening 56. Alternatively, the center 55a of the lower opening 55 may be offset from the center 56a of the upper opening 56.

[0065] The lower opening 55 may be defined by a pair of lower opening side edges 55b extending in the X direction. The lower opening side edges 55b are an example of a first opening side edge. The center 55a of the lower opening 55 described above may be the midpoint of the pair of lower opening side edges 55b when viewed in a cross section perpendicular to the X direction. In Figure 8A, the lower opening side edges 55b are shown as the intersections of the first main body surface 30a and the lower wall surfaces 53a and 53b, and the midpoint of these intersections may be the center 55a of the lower opening 55.

[0066] The upper opening 56 may be defined by a pair of upper opening side edges 56b extending in the X direction. The upper opening side edges 56b are an example of a second opening side edge. The center 56a of the upper opening 56 described above may be the midpoint of the pair of upper opening side edges 56b when viewed in a cross section perpendicular to the X direction. In Figure 8A, the upper opening side edges 56b are shown as the intersections of the second main body surface 30b and the upper wall surfaces 54a, 54b, and the midpoint of these intersections may be the center 56a of the upper opening 56.

[0067] As described above, the width w3 of the upper opening 56 may be larger than the width w2 of the lower opening 55. The upper opening 56 may extend from the region 56c that overlaps with the lower opening 55 in a plan view to the position that overlaps with the main channel groove 61, which will be described later, in a plan view. This makes it possible to increase the cross-sectional area of ​​the flow path recess 54 compared to the lower steam flow path recess 53. Here, as shown in Figure 8A, let P1 be the intersection point where a straight line extending in the Z direction through the second wall projection 58 intersects with the second lower sheet surface 10b. The region demarcated by the intersection point P1, the lower opening side edge 55b, the lower wall surface 53b, and the second wall projection 58 is defined as the lower steam flow path portion region. Let P2 be the intersection point where a straight line extending in the Z direction through the second wall projection 58 intersects with the first upper sheet surface 20a. The region demarcated by the intersection P2, the upper opening edge 56b, the upper wall surface 54b, and the second wall projection 58 is defined as the upper steam flow path portion. Since the upper steam flow path portion has a larger flow path cross-sectional area than the lower steam flow path portion, the capillary action in the upper steam flow path portion is smaller than that in the lower steam flow path portion. Therefore, the flow resistance of the working steam 2a in the upper steam flow path portion can be reduced, and the working steam 2a can be easily diffused to improve heat dissipation efficiency. The same applies to the region defined by the lower wall surface 53a and the upper wall surface 54a. On the other hand, a land portion 33 joined to the upper sheet 20 is formed between adjacent upper openings 56 in the Y direction. This ensures the mechanical strength of the vapor chamber 1. In this way, the vapor chamber 1 according to this embodiment improves heat dissipation efficiency while effectively utilizing the limited space and ensuring mechanical strength.

[0068] A portion of the upper opening 56 may overlap, in a plan view, with a portion of the main channel groove 61 adjacent to the steam passages 51 and 52. A portion of the upper opening 56 may overlap with multiple main channel grooves 61, in a plan view. The number of main channel grooves 61 that the upper opening 56 overlaps with is arbitrary.

[0069] An example of the positional relationship between the upper opening 56 and the main channel 61 will be explained with reference to Figures 8B to 8E. Here, the main channel 61 adjacent to the second steam passage 52 formed by one upper opening 56 will be referred to as main channel 61P, and the other main channel 61 adjacent to main channel 61P will be referred to as main channel 61Q. Main channel 61Q is located further from the center 55a of the lower opening 55 than main channel 61P. In other words, main channel 61Q is located further from the center 56a of the upper opening 56 than main channel 61P. In this embodiment, in a plan view, the center 55a of the lower opening 55 coincides with the center 56a of the upper opening 56. Below, the positional relationship between the upper opening 56 and the main channel 61 will be explained using the center 55a of the lower opening 55.

[0070] The main channels 61P and 61Q include a first main channel side edge 61a and a second main channel side edge 61b extending in the X direction. In Figures 8B to 8E, the first main channel side edge 61a and the second main channel side edge 61b are shown as intersections between the first main body surface 30a and the wall surface 62, which will be described later. The first main channel side edge 61a is located closer to the center 55a of the lower opening 55 than the second main channel side edge 61b, and the second main channel side edge 61b is located further from the center 55a of the lower opening 55 than the first main channel side edge 61a.

[0071] For example, as shown in Figure 8B, the upper opening 56 may extend to a position overlapping a portion of the main channel groove 61P in the Y direction. In this case, the upper opening side edge 56b may be located closer to the center 55a of the lower opening 55 than the second main channel groove side edge 61b of the main channel groove 61P in a plan view.

[0072] Alternatively, as shown in Figure 8C, the upper opening 56 may extend in the Y direction to a position that overlaps with the entire main channel groove 61P adjacent to the second steam passage 52. In this case, the upper opening side edge 56b may be located in a position that overlaps with the second main channel groove side edge 61b of the main channel groove 61P in a plan view, or it may be located further from the center 55a of the lower opening 55 than the second main channel groove side edge 61b of the main channel groove 61P. Alternatively, the upper opening side edge 56b may be located in a position that overlaps with the first main channel groove side edge 61a of the main channel groove 61Q in a plan view.

[0073] Alternatively, as shown in Figure 8D, the upper opening 56 may extend in the Y direction to a position that overlaps with a portion of the main channel groove 61Q. In this case, the upper opening side edge 56b may be located further from the center 55a of the lower opening 55 than the first main channel groove side edge 61a of the main channel groove 61Q, and closer to the center 55a of the lower opening 55 than the second main channel groove side edge 61b of the main channel groove 61Q.

[0074] Alternatively, as shown in Figure 8E, the upper opening 56 may extend in the Y direction to a position that overlaps with the entire main channel groove 61Q. In this case, the upper opening side edge 56b may be located in a position that overlaps with the second main channel groove side edge 61b of the main channel groove 61Q in a plan view, or it may be located further from the center 55a of the lower opening 55 than the second main channel groove side edge 61b of the main channel groove 61Q.

[0075] The above describes an example of the positional relationship between the upper opening 56 and the main channel 61 adjacent to the second steam passage 52 formed by the upper opening 56. The same applies to the positional relationship between the upper opening 56 and the main channel 61 adjacent to the first steam passage 51 formed by the upper opening 56.

[0076] As shown in Figure 10, when viewed in a cross-section perpendicular to the X direction, the upper opening 56 in the first steam passage 51 may extend from the region 56c that overlaps with the lower opening 55 in a plan view toward the outside of the frame portion 32 beyond the lower opening 55. The lower opening 55 and the upper opening 56 in the first steam passage 51 are located between the frame portion 32 and the land portion 33 adjacent to the frame portion 32. Here, the upper opening 56 in the portion of the first steam passage 51 extending in the X direction will be described. Similarly, in the portion of the first steam passage 51 extending in the Y direction, the width of the upper opening 56 may be greater than the width of the lower opening 55.

[0077] Let's explain in more detail. Assume that the pair of lower opening edges 55b described above are composed of a first lower opening edge 55ba and a second lower opening edge 55bb. The first lower opening edge 55ba defines the boundary between the frame portion 32 and the lower opening 55, and the second lower opening edge 55bb defines the boundary between the land portion 33 and the lower opening 55. Assume that the pair of upper opening edges 56b described above are composed of a first upper opening edge 56ba and a second upper opening edge 56bb. The first upper opening edge 56ba defines the boundary between the frame portion 32 and the upper opening 56, and the second upper opening edge 56bb defines the boundary between the land portion 33 and the upper opening 56.

[0078] The first upper opening edge 56ba is located outside the frame portion 32, compared to the first lower opening edge 55ba. In the example shown in Figure 10, the first upper opening edge 56ba is located to the left of the first lower opening edge 55ba.

[0079] When viewed in a cross-section perpendicular to the X direction, the upper opening 56 in the first steam passage 51 may extend from a region 56c that overlaps with the lower opening 55 in a plan view to a position that overlaps with the main channel groove 61 located in the land portion 33 in a plan view. The second upper opening side edge 56bb is located in a position that overlaps with the liquid flow channel portion 60 located in the land portion 33. In the example shown in Figure 10, the second upper opening side edge 56bb is located to the right of the second lower opening side edge 55bb.

[0080] As shown in Figure 8A, when viewed in a cross section perpendicular to the X direction, the upper opening 56 in the second steam passage 52 may extend from a region 56c that overlaps with the lower opening 55 in a plan view to a position that overlaps with the main channel groove 61 located in the land section 33 in a plan view. The upper opening 56 in the second steam passage 52 may extend from a region 56c that overlaps with the lower opening 55 in a plan view to a position that overlaps with the main channel groove 61 in a plan view on both sides of the lower opening 55.

[0081] Let's explain in more detail. Here, we assume that the second steam passage 52 is located between the adjacent first land section 33P and the second land section 33Q. The lower opening 55 and the upper opening 56 are located between the first land section 33P and the second land section 33Q.

[0082] When viewed in a cross-section perpendicular to the X direction, the upper opening 56 in the second steam passage 52 may extend from a position that coincides in a plan view with the main channel groove 61 located in the first land section 33P to a position that coincides in a plan view with the main channel groove 61 located in the second land section 33Q. Each upper opening side edge 56b is located in a position that coincides with the liquid flow channel section 60 of the corresponding land sections 33P and 33Q. In the example shown in Figure 8A, the upper opening side edge 56b located on the left is to the left of the lower opening side edge 55b located on the left. The upper opening side edge 56b located on the right is to the right of the lower opening side edge 55b located on the right.

[0083] As shown in Figure 8A, the distance w12 is indicated by the distance from each wall projection 57, 58 to the corresponding upper opening edge 56b. w12 may be, for example, 30 μm to 1400 μm. Distance w12 represents the planar distance between the first wall projection 57 and the left upper opening edge 56b, as well as the planar distance between the second wall projection 58 and the right upper opening edge 56b, when viewed in a cross section perpendicular to the X direction. Distance w12 corresponds to the dimension in the Y direction.

[0084] As shown in Figure 8A, the width of the land portion 33 on the second main body surface 30b is indicated by w13. w13 may be, for example, 30 μm to 2900 μm. The width w13 represents the distance from the upper opening side edge 56b defining one upper opening 56 to the upper opening side edge 56b defining the other upper opening 56, when viewed in a cross section perpendicular to the X direction. The width w13 corresponds to the dimension in the Y direction.

[0085] As shown in Figure 8A, the lower wall surfaces 53a and 53b of the lower steam flow recess 53 and the corresponding upper wall surfaces 54a and 54b of the upper steam flow recess 54 are connected by wall protrusions 57 and 58. More specifically, the lower wall surface 53a of the lower steam flow recess 53 and the corresponding upper wall surface 54a of the upper steam flow recess 54 are connected by a first wall protrusion 57. The lower wall surface 53b of the lower steam flow recess 53 and the corresponding upper wall surface 54b of the upper steam flow recess 54 are connected by a second wall protrusion 58. The first wall protrusion 57 is the left wall protrusion in Figure 8A, and the second wall protrusion 58 is the right wall protrusion in Figure 8A.

[0086] As shown in Figure 8A, the first wall projection 57 may project inward toward the steam passages 51 and 52. The second wall projection 58 may project inward toward the steam passages 51 and 52. In this embodiment, the pair of wall projections 57 and 58 project toward each other in directions along the first main body surface 30a and the second main body surface 30b.

[0087] In this embodiment, the first wall projection 57 is positioned at an intermediate position MP between the first main body surface 30a and the second main body surface 30b in the Z direction. However, the embodiment is not limited to this, and the first wall projection 57 may be positioned offset from the intermediate position MP. In the example shown in Figure 8A, the first wall projection 57 is positioned at the same position as the second wall projection 58 in the Z direction. However, the embodiment is not limited to this, and the first wall projection 57 may be positioned offset from the second wall projection 58 in the Z direction.

[0088] Similarly, in this embodiment, the second wall projection 58 is positioned at an intermediate position MP between the first main body surface 30a and the second main body surface 30b in the Z direction. However, this is not the only way in which the second wall projection 58 can be positioned offset from the intermediate position MP. In the example shown in Figure 8A, the second wall projection 58 is positioned at the same position as the first wall projection 57 in the Z direction. However, this is not the only way in which the second wall projection 58 can be positioned offset from the first wall projection 57 in the Z direction.

[0089] A penetrating portion 34 is defined by a pair of wall projections 57 and 58, and within the penetrating portion 34, the lower steam flow recess 53 and the upper steam flow recess 54 are in communication with each other. In this embodiment, the planar shape of the penetrating portion 34 in the first steam passage 51 is a rectangular frame shape, similar to that of the first steam passage 51. The planar shape of the penetrating portion 34 in the second steam passage 52 is an elongated rectangular shape, similar to that of the second steam passage 52. The width w4 of such a penetrating portion 34 (see Figure 8A) may be, for example, 200 μm to 500 μm. Here, the width w4 of the penetrating portion 34 corresponds to the gap between adjacent land portions 33 in the Y direction. More specifically, the width w4 means the distance in the Y direction between the tip of the first wall projection 57 and the tip of the second wall projection 58 that define the penetrating portion 34.

[0090] When viewed in a cross-section perpendicular to the X direction, the upper steam flow recess 54 may include two flat surfaces 59a and 59b. Each flat surface 59a and 59b connects to the corresponding upper wall surfaces 54a and 54b and wall projections 57 and 58. Flat surface 59a is the left surface in Figure 8A, and flat surface 59b is the right surface in Figure 8A. More specifically, the upper wall surface 54a is connected to the first wall projection 57 via one flat surface 59a, and flat surface 59a is formed between the upper wall surface 54a and the first wall projection 57. The upper wall surface 54b is connected to the second wall projection 58 via the other flat surface 59b, and flat surface 59b is formed between the upper wall surface 54b and the second wall projection 58. The flat surfaces 59a and 59b may be aligned with the second main surface 30b when viewed in a cross-section perpendicular to the X direction. In this case, the flat surfaces 59a and 59b may be parallel to the second main surface 30b or parallel to the first main surface 30a. However, the flat surfaces 59a and 59b may be inclined with respect to the second main surface 30b. Both of the two flat surfaces 59a and 59b may be aligned with the second main surface 30b or both may be inclined with respect to the second main surface 30b. Alternatively, one of the two flat surfaces 59a and 59b may be aligned with the second main surface 30b while the other is inclined with respect to the second main surface 30b.

[0091] The flat surfaces 59a and 59b may be formed in a flat shape. For example, the flat surfaces 59a and 59b may be formed such that, when viewed in a cross section perpendicular to the X direction, they are included within a range of less than 3 μm in a direction perpendicular to the flat surfaces 59a and 59b. For example, when viewed in a cross section perpendicular to the X direction, they may be included within a range of less than 3 μm in a direction perpendicular to the reference line connecting the wall projections 57 and 58 and the endpoints of the upper wall surfaces 54a and 54b.

[0092] Refer to Figure 8F for a more detailed explanation of the flat surfaces 59a and 59b. For clarity, we will describe flat surface 59b as a representative example. Since flat surface 59a is similar to flat surface 59b, a detailed explanation of it will be omitted.

[0093] As shown in Figure 8F, a reference line corresponding to the flat surface 59b is indicated by a line denoted by reference numeral 59c. The reference line 59c may be a straight line connecting the second wall projection 58 and the endpoint 54c of the upper wall surface 54b. The endpoint 54c may be the point on the upper wall surface 54b closest to the second wall projection 58. The flat surface 59b may be formed within the range 59f between the first boundary line 59d and the second boundary line 59e. The first boundary line 59d is a line shifted from the reference line 59c in the direction toward the first main surface 30a and may be parallel to the reference line 59c. The second boundary line 59e is a line shifted from the reference line 59c in the direction toward the second main surface 30b and may be parallel to the reference line 59c. The flat surface 59b may be formed within the range 59f between the first boundary line 59d and the second boundary line 59e as defined in this way.

[0094] As shown in Figure 8F, the reference line 59c may be along the second main surface 30b. In this case, the first boundary line 59d and the second boundary line 59e may also be along the second main surface 30b. However, the reference line 59c may be inclined with respect to the second main surface 30b. In this case, the first boundary line 59d and the second boundary line 59e may also be inclined with respect to the second main surface 30b.

[0095] As shown in Figure 8F, the distance between the first boundary line 59d and the reference line 59c and the distance between the second boundary line 59e and the reference line 59c may be equal. In this case, for example, the distance between the first boundary line 59d and the reference line 59c may be less than 1.5 μm. For example, the distance between the second boundary line 59e and the reference line 59c may be less than 1.5 μm. However, the distance between the first boundary line 59d and the reference line 59c and the distance between the second boundary line 59e and the reference line 59c are not limited to being equal. If the distance between the first boundary line 50d and the second boundary line 59e is less than 3.0 μm, the distance between the first boundary line 59d and the reference line 59c and the distance between the second boundary line 59e and the reference line 59c may be different. The first boundary line 59d may overlap with the reference line 59c, or the second boundary line 59e may overlap with the reference line 59c.

[0096] As shown in Figure 8A, the depth of the upper steam flow channel recess 54 is indicated by h2. h2 may be, for example, 20 μm to 250 μm. Depth h2 represents the distance from the second main body surface 30b to the flat surfaces 59a, 59b when viewed in a cross section perpendicular to the X direction. Depth h2 corresponds to the dimension in the Z direction.

[0097] The width w3 of the upper opening 56 may be larger than the width w2 of the lower opening 55 over the entire area of ​​the land portion 33 in the X direction. This allows the flow path cross-sectional area of ​​the steam passages 51 and 52 to be increased over the entire area of ​​the land portion 33 in the X direction.

[0098] The steam flow path section 50, including the first steam passage 51 and the second steam passage 52 configured in this way, constitutes a part of the sealed space 3 described above. As shown in Figure 3, the steam flow path section 50 according to this embodiment is mainly defined by the lower sheet 10, the upper sheet 20, and the frame portion 32 and land portion 33 of the wick sheet 30 described above. Each steam passage 51, 52 has a relatively large flow path cross-sectional area to allow the working steam 2a to pass through.

[0099] Here, Figure 3 shows an enlarged view of the first steam passage 51 and the second steam passage 52, etc., for clarity, and the number and arrangement of these steam passages 51, 52, etc. differ from those in Figures 2, 6, and 7.

[0100] Incidentally, although not shown in the figures, multiple support parts may be provided within the steam flow path section 50 to support the land section 33 on the frame section 32. Also, support parts may be provided to support adjacent land sections 33 to each other. These support parts may be provided on both sides of the land section 33 in the X direction, or on both sides of the land section 33 in the Y direction. The support parts may be formed so as not to obstruct the flow of working steam 2a diffusing through the steam flow path section 50. For example, they may be arranged on one side of the first main body surface 30a and the second main body surface 30b of the wick sheet 30, with a space forming a steam flow path on the other side. This makes the thickness of the support parts thinner than the thickness of the wick sheet 30, preventing the first steam passage 51 and the second steam passage 52 from being divided in the X and Y directions.

[0101] As shown in Figures 6 and 7, alignment holes 35 may be provided at the four corners of the wick sheet 30, similar to the lower sheet 10 and the upper sheet 20.

[0102] As shown in Figure 2, the vapor chamber 1 may further include an injection section 4 at one end edge in the X direction for injecting the working fluid 2b into the sealed space 3. In the configuration shown in Figure 2, the injection section 4 is located on the side of the evaporation region SR and protrudes to the outside of the vapor chamber 1 from the end edge on the evaporation region SR side. Note that the injection section 4 does not have to protrude to the outside of the vapor chamber 1, as shown in Figure 36 and other figures described later.

[0103] More specifically, the injection section 4 may have a lower injection projection 11 (see Figure 4), an upper injection projection 21 (see Figure 5), and a wick sheet injection projection 36 (see Figures 6 and 7). The lower injection projection 11 constitutes the lower sheet 10. The upper injection projection 21 constitutes the upper sheet 20. The wick sheet injection projection 36 constitutes the wick sheet 30. An injection channel 37 is formed in the wick sheet injection projection 36. This injection channel 37 may extend from the first main body surface 30a to the second main body surface 30b of the wick sheet 30, or it may penetrate the wick sheet injection projection 36 of the wick sheet 30 in the Z direction. The injection channel 37 is also in communication with the vapor channel section 50, and the working fluid 2b is injected into the sealed space 3 by passing through the injection channel 37. Depending on the arrangement of the liquid flow channel section 60, the injection channel 37 may be connected to the liquid flow channel section 60. The upper and lower surfaces of the wick sheet injection projection section 36 may be formed in a generally flat shape, and the upper surface of the lower injection projection section 11 and the lower surface of the upper injection projection section 21 may also be formed in a generally flat shape. The planar shapes of each injection projection section 11, 21, and 36 may be the same.

[0104] In this embodiment, the injection section 4 is shown as being located on one of a pair of edges in the X direction of the vapor chamber 1, but it is not limited to this and can be located at any position. Furthermore, the injection channel 37 provided in the wick sheet injection projection 36 does not need to penetrate the wick sheet injection projection 36, as long as it can inject the working fluid 2b. In this case, the injection channel 37 communicating with the vapor channel section 50 can be formed in a recess formed in one of the first main body surface 30a and the second main body surface 30b of the wick sheet 30.

[0105] As shown in Figures 3, 8A, and 10, the liquid flow path section 60 may be provided between the lower sheet 10 and the wick sheet 30. In this embodiment, the liquid flow path section 60 is provided on the first main body surface 30a of the wick sheet 30. The liquid flow path section 60 may be a flow path mainly through which the working fluid 2b passes. The working vapor 2a described above may also pass through the liquid flow path section 60. The liquid flow path section 60 constitutes a part of the sealed space 3 described above and is in communication with the vapor flow path section 50. The liquid flow path section 60 is configured as a capillary structure (wick) for transporting the working fluid 2b to the evaporation region SR. In this embodiment, the liquid flow path section 60 is provided on the first main body surface 30a of each land portion 33 of the wick sheet 30. The liquid flow path section 60 may be formed over the entire first main body surface 30a of each land portion 33. Although not shown in Figure 3, etc., the liquid flow path section 60 may be provided on the second main body surface 30b of each land portion 33.

[0106] As shown in Figure 9, the fluid flow channel section 60 is an example of a groove assembly containing multiple grooves. More specifically, the fluid flow channel section 60 has multiple main channel grooves 61 through which the working fluid 2b passes, and multiple connecting grooves 65 that communicate with the main channel grooves 61. The main channel grooves 61 of the fluid flow channel section 60 are an example of a first groove. The connecting grooves 65 of the fluid flow channel section 60 are an example of a second groove. The main channel grooves 61 and the connecting grooves 65 are grooves through which the working fluid 2b passes. The connecting grooves 65 communicate with the main channel grooves 61.

[0107] Each main channel groove 61 is formed to extend in the X direction, as shown in Figure 9. The main channel groove 61 has a smaller flow path cross-sectional area than the first steam passage 51 or the second steam passage 52 of the steam flow path section 50, primarily so that the working fluid 2b flows by capillary action. In this way, the main channel groove 61 is configured to transport the working fluid 2b condensed from the working steam 2a to the evaporation region SR. Each main channel groove 61 may be arranged at equal intervals along the Y direction perpendicular to the X direction.

[0108] The main groove 61 is formed by etching from the first main surface 30a of the wick sheet 30 in an etching process described later. As a result, the main groove 61 has a curved wall surface 62, as shown in Figure 8A. This wall surface 62 defines the main groove 61 and is curved in a shape that bulges out toward the second main surface 30b.

[0109] As shown in Figures 8A and 9, the width w5 (dimension in the Y direction) of the main groove 61 may be, for example, 5 μm to 400 μm. Note that the width w5 of the main groove 61 refers to the dimension on the first main body surface 30a. Also, as shown in Figure 8A, the depth h1 (dimension in the Z direction) of the main groove 61 may be, for example, 5 μm to 100 μm.

[0110] As shown in Figure 9, each connecting groove 65 extends in a direction different from the X direction. In this embodiment, each connecting groove 65 is formed to extend in the Y direction and is formed perpendicular to the main channel groove 61. Some connecting grooves 65 are arranged to connect adjacent main channel grooves 61 to each other. Other connecting grooves 65 are arranged to connect the steam flow path section 50 (first steam passage 51 or second steam passage 52) to the main channel groove 61. That is, these connecting grooves 65 extend from the side edge 33a of the land section 33 in the Y direction to the main channel groove 61 adjacent to that side edge 33a. In this way, the first steam passage 51 or second steam passage 52 of the steam flow path section 50 and the main channel groove 61 are connected.

[0111] The connecting grooves 65 have a smaller flow path cross-sectional area than the first steam passage 51 or the second steam passage 52 of the steam flow path section 50, primarily so that the working fluid 2b flows by capillary action. Each connecting groove 65 may be arranged at equal intervals along the X direction.

[0112] The connecting groove 65, like the main channel groove 61, is formed by etching and has a curved wall surface (not shown) similar to that of the main channel groove 61. As shown in Figure 9, the width w6 (dimension in the X direction) of the connecting groove 65 may be equal to the width w5 of the main channel groove 61, but may be greater or less than w5. The depth of the connecting groove 65 may be equal to the depth h1 of the main channel groove 61, but may be deeper or shallower than h1.

[0113] As shown in Figure 9, the fluid flow channel section 60 has rows of protrusions 63 provided on the first main surface 30a of the wick sheet 30. The rows of protrusions 63 are provided between adjacent main channel grooves 61. Each row of protrusions 63 includes a plurality of protrusions 64 (an example of fluid flow channel protrusions) arranged in the X direction. The protrusions 64 are provided within the fluid flow channel section 60 and are in contact with the upper sheet 20. Each protrusion 64 is formed in a rectangular shape with the X direction as its longitudinal direction in a plan view. Main channel grooves 61 are interposed between adjacent protrusions 64 in the Y direction, and connecting grooves 65 are interposed between adjacent protrusions 64 in the X direction. The connecting grooves 65 are formed to extend in the Y direction and connect adjacent main channel grooves 61 in the Y direction. This allows the working fluid 2b to flow between these main channel grooves 61.

[0114] The protrusions 64 are the parts of the wick sheet 30 that remain unetched in the etching process described later. In this embodiment, as shown in Figure 9, the planar shape of the protrusions 64 is the shape at the position of the first main surface 30a of the wick sheet 30, and it is rectangular.

[0115] In this embodiment, the protrusions 64 are arranged in a staggered pattern. More specifically, the protrusions 64 of adjacent rows 63 in the Y direction are offset from each other in the X direction. This offset may be half the arrangement pitch of the protrusions 64 in the X direction. The width w7 (dimension in the Y direction) of the protrusions 64 may be, for example, 5 μm to 500 μm. Note that the width w7 of the protrusions 64 refers to the dimension on the first main body surface 30a. Note that the arrangement of the protrusions 64 is not limited to a staggered pattern, and they may be arranged in parallel. In this case, the protrusions 64 of adjacent rows 63 in the Y direction are aligned in the Y direction as well.

[0116] The main channel groove 61 includes an intersection 66 that communicates with a connecting channel groove 65. At the intersection 66, the main channel groove 61 and the connecting channel groove 65 communicate in a T-shape. This prevents the connecting channel groove 65 on the other side (for example, the lower side in Figure 9) from communicating with the main channel groove 61 at the intersection 66 where one main channel groove 61 communicates with the connecting channel groove 65 on one side (for example, the upper side in Figure 9).

[0117] In other words, when connecting grooves 65 located on both sides of a main channel groove 61 in the Y direction (both upper and lower sides in Figure 9) are positioned at the same location in the X direction, the main channel groove 61 and the connecting grooves 65 intersect in a cross shape. In this case, the wall surface 62 of the main channel groove 61 (see Figure 8A) is cut out on both sides (upper and lower sides in Figure 9) by the connecting grooves 65 at the same location in the X direction. At this cut-out location, a continuous space is formed in a cross shape, which can reduce the capillary action of the main channel groove 61.

[0118] In contrast, according to this embodiment, the connecting grooves 65 located on both sides of a single main channel groove 61 in the Y direction (both upper and lower sides in Figure 9) are positioned at different locations in the X direction. This makes it possible to make the position where the wall surface 62 of the main channel groove 61 is cut out by the connecting groove 65 on one side in the Y direction differ from the position where it is cut out by the connecting groove 65 on the other side in the Y direction. In this case, since the main channel groove 61 communicates with the connecting groove 65 on one side in the Y direction, the wall surface 62 of the main channel groove 61 can remain on the other side in the Y direction. Therefore, at the position where the wall surface 62 of the main channel groove 61 is cut out by the connecting groove 65, a continuous space is formed in a T shape, which can suppress a decrease in the capillary action of the main channel groove 61. As a result, it is possible to suppress a decrease in the propulsive force of the working fluid 2b toward the evaporation region SR at the intersection 66.

[0119] Incidentally, the materials constituting the lower sheet 10, upper sheet 20, and wick sheet 30 are not particularly limited, as long as they have sufficient thermal conductivity to ensure the heat dissipation efficiency of the vapor chamber 1. For example, the materials for each of the sheets 10, 20, and 30 include copper or copper alloys that have good thermal conductivity and corrosion resistance when pure water is used as the working fluid. Examples of copper include pure copper and oxygen-free copper (C1020). Examples of copper alloys include copper alloys containing tin, copper alloys containing titanium (C1990, etc.), and Corson-type copper alloys (C7025, etc.) which contain nickel, silicon, and magnesium. An example of a copper alloy containing tin is phosphor bronze (C5210, etc.).

[0120] The thickness t1 of the vapor chamber 1 shown in Figure 3 may be, for example, 100 μm to 500 μm. By making the thickness t1 of the vapor chamber 1 100 μm or more, the vapor flow path 50 can be properly secured, allowing the vapor chamber 1 to function properly. On the other hand, by making the thickness t1 500 μm or less, it is possible to suppress the thickness t1 of the vapor chamber 1 from becoming too thick.

[0121] The thickness of the wick sheet 30 may be greater than the thickness of the lower sheet 10. Similarly, the thickness of the wick sheet 30 may be greater than the thickness of the upper sheet 20. In this embodiment, an example is shown where the thickness of the lower sheet 10 and the upper sheet 20 are equal, but this is not the only example, and the thicknesses of the lower sheet 10 and the upper sheet 20 may be different.

[0122] The thickness t2 of the lower sheet 10 may be, for example, 6 μm to 100 μm. By setting the thickness t2 of the lower sheet 10 to 6 μm or more, the mechanical strength and long-term reliability of the lower sheet 10 can be ensured. On the other hand, by setting the thickness t2 of the lower sheet 10 to 100 μm or less, it is possible to suppress an increase in the thickness t1 of the vapor chamber 1. Similarly, the thickness t3 of the upper sheet 20 may be set in the same way as the thickness t2 of the lower sheet 10.

[0123] The thickness t4 of the wick sheet 30 may be, for example, 50 μm to 300 μm. By making the thickness t4 of the wick sheet 30 50 μm or more, the vapor flow path 50 can be properly secured, allowing the vapor chamber 1 to operate properly. On the other hand, by making it 300 μm or less, it is possible to suppress an increase in the thickness t1 of the vapor chamber 1. Note that the thickness t4 of the wick sheet 30 may also be the distance between the first main body surface 30a and the second main body surface 30b.

[0124] The vapor chamber 1 according to this embodiment, having the configuration described above, can be manufactured by referring to the manufacturing method described later with reference to Figures 18 to 23. The flat surfaces 59a and 59b of the upper vapor flow channel recess 54 can be easily formed by adjusting etching conditions such as the shape of the resist, the way the etching solution is flowed, or the etching time.

[0125] Next, we will explain how the vapor chamber 1 operates, that is, how the electronic device D is cooled.

[0126] The vapor chamber 1 obtained as described above is installed in a housing H of a mobile terminal or the like, with the housing member Ha attached to the second upper seat surface 20b of the upper sheet 20. Alternatively, the vapor chamber 1 is attached to the housing member Ha. In addition, an electronic device D, such as a CPU, which is the device to be cooled, is attached to the first lower seat surface 10a of the lower sheet 10. Alternatively, the vapor chamber 1 is attached to the electronic device D. The working fluid 2b in the sealed space 3 adheres to the walls of the sealed space 3 due to its surface tension. More specifically, the working fluid 2b adheres to the lower wall surfaces 53a, 53b of the lower vapor flow recess 53, the upper wall surfaces 54a, 54b of the upper vapor flow recess 54, the flat surfaces 59a, 59b, the wall surface 62 of the main channel groove 61, and the wall surface of the connecting groove 65. The working fluid 2b may also adhere to the portion of the second lower seat surface 10b of the lower sheet 10 that is exposed to the lower vapor flow recess 53. The working fluid 2b may also adhere to the portion of the first upper sheet surface 20a of the upper sheet 20 that is exposed to the upper vapor flow channel recess 54, the main channel groove 61, and the connecting groove 65.

[0127] When the electronic device D generates heat in this state, the working fluid 2b present in the evaporation region SR (see Figures 6 and 7) receives heat from the electronic device D. The received heat is absorbed as latent heat, causing the working fluid 2b to evaporate (vaporize) and generate working steam 2a. Much of the generated working steam 2a diffuses within the first steam passage 51 and the second steam passage 52 that constitute the sealed space 3 (see the solid arrows in Figure 7). More specifically, in the portion of the first steam passage 51 extending in the X direction and in the second steam passage 52 of the steam flow path section 50, the working steam 2a diffuses mainly in the X direction. On the other hand, in the portion of the first steam passage 51 extending in the Y direction, the working steam 2a diffuses mainly in the Y direction. In this embodiment, the upper opening 56 is larger than the lower opening 55, which increases the flow path cross-sectional area of ​​the steam passages 51 and 52. As a result, the flow path resistance of the working steam 2a is reduced, and the working steam 2a can diffuse smoothly.

[0128] Then, the working steam 2a in each steam passage 51, 52 leaves the evaporation region SR, and most of the working steam 2a is transported to the relatively lower temperature condensation region CR (the right-hand portion in Figures 6 and 7). In the condensation region CR, the working steam 2a is cooled mainly by radiating heat to the upper sheet 20. The heat absorbed by the upper sheet 20 from the working steam 2a is transferred to the outside air via the housing member Ha (see Figure 3).

[0129] The working vapor 2a condenses in the evaporation region SR by releasing heat to the upper sheet 20 in the condensation region CR, losing the latent heat absorbed in the evaporation region SR, and generating working fluid 2b. The generated working fluid 2b adheres to the walls 53a, 53b, 54a, 54b, the flat surfaces 59a, 59b of each vapor flow channel recess 53, 54, the second lower sheet surface 10b of the lower sheet 10, and the first upper sheet surface 20a of the upper sheet 20. Here, the working fluid 2b continues to evaporate in the evaporation region SR. Therefore, the working fluid 2b in the region of the liquid flow channel 60 other than the evaporation region SR (i.e., the condensation region CR) is transported toward the evaporation region SR by the capillary action of each main channel groove 61 (see dashed arrows in Figure 7). As a result, the working fluid 2b adhering to each wall surface 53a, 53b, 54a, 54b, flat surfaces 59a, 59b, second lower sheet surface 10b, and first upper sheet surface 20a moves to the fluid flow channel section 60, passes through the connecting groove 65, and enters the main channel groove 61. In this way, each main channel groove 61 and each connecting groove 65 are filled with working fluid 2b. Therefore, the filled working fluid 2b gains a propulsive force toward the evaporation region SR due to the capillary action of each main channel groove 61 and is smoothly transported toward the evaporation region SR.

[0130] In the fluid flow channel section 60, each main channel groove 61 is connected to an adjacent main channel groove 61 via a corresponding connecting groove 65. This allows the working fluid 2b to flow between adjacent main channel grooves 61, suppressing the occurrence of dryout in the main channel grooves 61. As a result, capillary action is imparted to the working fluid 2b in each main channel groove 61, and the working fluid 2b is smoothly transported toward the evaporation region SR.

[0131] On the other hand, the working fluid 2b adhering to the wall surfaces 53a, 53b, 54a, 54b and the flat surfaces 59a, 59b of each steam channel recess 53, 54 can also be transported to the evaporation region SR by the capillary action of the steam channel recesses 53, 54. The steam channel recesses 53, 54 primarily function as channels for working steam 2a, but the working fluid 2b adhering to the wall surfaces 53a, 53b, 54a, 54b and the flat surfaces 59a, 59b can also be subjected to capillary action.

[0132] The working fluid 2b, having reached the evaporation region SR, receives heat again from the electronic device D and evaporates. The working vapor 2a evaporated from the working fluid 2b moves through the connecting groove 65 in the evaporation region SR to the lower vapor flow channel recess 53 and the upper vapor flow channel recess 54, which have larger flow channel cross-sectional areas, and diffuses within each vapor flow channel recess 53 and 54. In this way, the working fluids 2a and 2b recirculate within the sealed space 3 while repeatedly undergoing phase changes, i.e., evaporation and condensation, diffusing and releasing the heat from the electronic device D. As a result, the electronic device D is cooled.

[0133] As described above, according to this embodiment, when viewed in a cross-section perpendicular to the X direction, the upper opening 56 located on the second main body surface 30b extends from a region 56c that overlaps with the lower opening 55 located on the first main body surface 30a in a plan view to a position that overlaps with the main channel groove 61 in a plan view. This increases the flow path cross-sectional area of ​​the steam passages 51 and 52. As a result, the flow path resistance of the working steam 2a can be reduced, and the working steam 2a can be easily diffused. Consequently, the heat dissipation efficiency of the vapor chamber 1 can be improved, and the cooling efficiency of the electronic device D can be improved.

[0134] Furthermore, according to this embodiment, when viewed in a cross-section perpendicular to the X direction, the upper steam flow path recess 54 includes flat surfaces 59a and 59b that connect the corresponding upper wall surfaces 54a and wall projections 57 and 58. The flat surfaces 59a and 59b are formed in a flat shape. This further reduces the flow resistance of the working steam 2a and allows the working steam 2a to diffuse more easily.

[0135] Furthermore, according to this embodiment, when viewed in a cross-section perpendicular to the X direction, the upper opening 56 extends from a region 56c that overlaps with the lower opening 55 in a plan view to a position that overlaps with the main channel groove 61 in a plan view on both sides of the lower opening 55. This allows for a further increase in the flow path cross-sectional area of ​​the steam passages 51 and 52. As a result, the flow path resistance of the working steam 2a can be reduced, and the working steam 2a can be easily diffused. Consequently, the heat dissipation efficiency of the vapor chamber 1 can be improved, and the cooling efficiency of the electronic device D can be improved.

[0136] In the embodiment described above, the upper opening 56 was described as extending from a region 56c that overlaps with the lower opening 55 in a plan view, to a position that overlaps with the main channel 61 in a plan view, on both sides of the lower opening 55. However, it is not limited to this. For example, as shown in Figure 11, the upper opening 56 may extend from a region 56c that overlaps with the lower opening 55 in a plan view, to a position that overlaps with the main channel 61 in a plan view, on one side of the lower opening 55. The upper opening 56 does not have to extend to a position that overlaps with the main channel 61 in a plan view, on the other side of the lower opening 55. Even in this case, the flow path cross-sectional area of ​​the steam passages 51 and 52 can be increased. In the example shown in Figure 11, the upper opening 56 extends to the left of the lower opening 55. When viewed in a cross-section perpendicular to the X direction, the upper steam flow path recess 54 includes one flat surface 59a. The flat surface 59a is located on the side from which the upper opening 56 extends. The flat surface 59a connects one upper wall surface 54a to the first wall projection 57. The other upper wall surface 54b and the second wall projection 58 are connected without the intervening flat surface 59b (see Figure 8A). The upper opening side edge 56b, located on the opposite side of the flat surface 59a, may be positioned to overlap with the corresponding lower opening side edge 55b in a plan view. In the example shown in Figure 11, the center 55a of the lower opening 55 and the center 56a of the upper opening 56 may be offset from each other.

[0137] Furthermore, in the above-described embodiment, an example was described in which the upper steam flow recess 54 includes flat surfaces 59a and 59b when viewed in a cross section perpendicular to the X direction. However, it is not limited to this. For example, as shown in Figure 12, the upper steam flow recess 54 may include convex surfaces 75a and 75b. The convex surfaces 75a and 75b connect the corresponding upper wall surfaces 54a and 54b to the wall projections 57 and 58. The convex surface 75a is the left surface in Figure 12, and the convex surface 75b is the right surface in Figure 12. More specifically, the upper wall surface 54a is connected to the first wall projection 57 via one convex surface 75a, and the upper wall surface 54b is connected to the second wall projection 58 via the other convex surface 75b. The convex surfaces 75a and 75b each include a spatial convex portion 76. The spatial protrusion 76 extends in the X direction and protrudes toward the second main body surface 30b. This allows the working steam 2a to flow along the spatial protrusion 76. As a result, the flow resistance of the working steam 2a can be reduced, and the working steam 2a can be diffused more easily. The protruding surfaces 75a and 75b may each contain a plurality of spatial protrusions 76 spaced apart from each other. A concave curved surface 77 may be formed between two adjacent spatial protrusions 76. A concave curved surface 77 may also be formed between the wall protrusions 57 and 58 and adjacent spatial protrusions 76. In the example shown in Figure 12, the protruding surfaces 75a and 75b contain two spatial protrusions 76. In this case, the working steam 2a can be rectified even more.

[0138] As shown in Figure 12, the depth of the upper steam channel recess 54 is indicated by h3. h3 may be, for example, 20 μm to 250 μm. Depth h3 represents the maximum distance from the second main body surface 30b to the convex surfaces 75a, 75b when viewed in a cross section perpendicular to the X direction. Depth h3 corresponds to the dimension in the Z direction.

[0139] As shown in Figure 12, the depth from the second main body surface 30b to the spatial protrusion 76 is indicated by h4. h4 may be, for example, 17 μm to 245 μm. The depth h4 represents the distance from the second main body surface 30b to the tip of the spatial protrusion 76 when viewed in a cross section perpendicular to the X direction. The depth h4 corresponds to the dimension in the Z direction.

[0140] As shown in Figure 12, the spacing of the spatial protrusions 76 is indicated by w14. w14 may be, for example, 30 μm to 300 μm. The spacing w14 represents the pitch distance between adjacent spatial protrusions 76 when viewed in a cross section perpendicular to the X direction. The spacing w14 corresponds to the dimension in the Y direction.

[0141] Furthermore, in the embodiment described above, an example was described in which the upper steam flow recess 54 includes flat surfaces 59a and 59b when viewed in a cross section perpendicular to the X direction. However, it is not limited to this. For example, as shown in Figure 13, the upper steam flow recess 54 does not have to include flat surfaces 59a and 59b. More specifically, the upper wall surfaces 54a and 54b and the wall projections 57 and 58 are connected without the intervening flat surfaces 59a and 59b. Even in this case, it is sufficient that the upper opening 56 located on the second main body surface 30b extends from the region 56c that overlaps with the lower opening 55 located on the first main body surface 30a in a plan view to the position that overlaps with the main channel groove 61 in a plan view. This increases the flow cross-sectional area of ​​the steam passages 51 and 52 and reduces the flow resistance of the working steam 2a.

[0142] Furthermore, in the embodiment described above, an example was described in which the lower wall surfaces 53a and 53b of the lower steam flow path recess 53 are curved in a concave shape. However, it is not limited to this. As shown in Figure 14, the lower wall surfaces 53a and 53b may be curved in a convex shape. Each lower wall surface 53a and 53b may be connected to the upper wall surfaces 54a and 54b without the interposition of wall protrusions 57 and 58. Each lower wall surface 53a and 53b may be connected to the upper wall surfaces 54a and 54b without the interposition of flat surfaces 59a and 59b. In this way, by curving the lower wall surfaces 53a and 53b in a convex shape, the formation of wall protrusions 57 and 58 can be avoided. Therefore, the flow path cross-sectional area of ​​the steam passages 51 and 52 can be increased, and the flow path resistance of the working steam 2a can be reduced. The lower wall surfaces 53a and 53b and the upper wall surfaces 54a and 54b may be connected via flat surfaces 59a and 59b.

[0143] Furthermore, in the embodiment described above, an example was described in which the width w3 of the upper opening 56 is larger than the width w2 of the lower opening 55 over the entire area of ​​the land portion 33 in the X direction. However, it is not limited to this. For example, as shown in Figure 15A, the area in which the width w3 of the upper opening 56 is larger than the width w2 of the lower opening 55 may be only a part of the area of ​​the land portion 33 in the X direction.

[0144] In the example shown in Figure 15A, the upper opening 56 includes a first region 56d and a second region 56e. The first region 56d is the region where the upper opening 56 extends from the region 56c that overlaps the lower opening 55 in a plan view to the position where it overlaps the main channel groove 61 in a plan view. The second region 56e is the region where the upper opening 56 does not extend from the region 56c that overlaps the lower opening 55 in a plan view to the position where it overlaps the main channel groove 61 in a plan view. In the first region 56d, the width w3 is greater than the width w2. In the second region 56e, the width w3 is smaller than the width w3 in the first region 56d, for example, as shown in Figure 15B. In the second region 56e, the width w3 may be equal to the width w2, and the upper opening 56 may overlap the lower opening 55 in a plan view. More specifically, the upper opening edge 56b is positioned to overlap with the corresponding lower opening edge 55b in a plan view, and the upper opening edge 56b is positioned to overlap with the corresponding lower opening edge 55b in a plan view. This increases the contact area between the land portion 33 and the upper sheet 20, thereby improving the mechanical strength of the vapor chamber 1.

[0145] The positions of the first region 56d and the second region 56e in the X direction are arbitrary. For example, the first region 56d may be located in the evaporation region SR and the second region 56e may be located in the condensation region CR. In this case, the flow path cross-sectional area of ​​the steam passages 51 and 52 can be increased in the evaporation region SR, where the pressure of the working steam 2a tends to be high.

[0146] For example, the first region 56d may be located in the condensation region CR, and the second region 56e may be located in the evaporation region SR. In this case, the flow rate of the working vapor 2a can be reduced in the condensation region CR, thereby promoting condensation.

[0147] For example, the first region 56d may be located in the middle of the vapor chamber 1 in the X direction. The first region 56d may also be located in the region of the condensation region CR that is close to the evaporation region SR. In this case, the flow resistance of the working vapor diffused from the evaporation region SR can be reduced, and the working vapor 2a can be diffused to a location far from the evaporation region SR. This improves the heat dissipation efficiency of the vapor chamber 1.

[0148] (Second Embodiment) Next, the main body sheet, vapor chamber, and electronic equipment for a second embodiment of the present invention will be described with reference to Figures 16 to 25.

[0149] In the second embodiment shown in Figures 16 to 25, the main difference is that the first wall projection is offset from the intermediate position between the first and second main body surfaces in the direction normal to the first main body surface. The other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 15. In Figures 16 to 25, the same reference numerals are used for parts that are the same as those in the first embodiment shown in Figures 1 to 15, and detailed descriptions are omitted.

[0150] As shown in Figures 16 and 17, when viewed in a cross-section perpendicular to the X direction, the center 55a of the lower opening 55 is offset from the center 56a of the upper opening 56. More specifically, in the portion of the first steam passage 51 extending in the X direction, the center 55a of the lower opening 55 is offset to one side in the Y direction relative to the center 56a of the upper opening 56. Similarly, in the second steam passage 52, the center 55a of the lower opening 55 is offset to one side in the Y direction relative to the center 56a of the upper opening 56. Thus, in this embodiment, the cross-sectional shapes of the first steam passage 51 and the second steam passage 52 may be asymmetrical in the Y direction.

[0151] Figures 16 and 17 show an example where the center 55a of the lower opening 55 is offset to the right relative to the center 56a of the upper opening 56, but it may also be offset to the left. As shown in Figure 17, the amount of offset s1 between the center 55a of the lower opening 55 and the center 56a of the upper opening 56 may be, for example, 0.05 mm to (0.8 × w1) mm. By setting it to 0.05 mm or more, the effects described later due to the offset between the centers 55a and 56a can be realized. On the other hand, by setting the amount of offset s1 to (0.8 × w1) mm or less, it can be set to 80% or less of the width w1 of the land portion 33. In this case, the mechanical strength of the land portion 33 can be ensured, and deformation of the wick sheet 30 when a load is applied, such as during diffusion bonding, can be suppressed. Note that in Figures 2, 6, and 7, for clarity of the drawings, the state in which the center 55a of the lower opening 55 and the center 56a of the upper opening 56 are not offset is shown.

[0152] The width w1 of the land portion 33 in this embodiment (see Figure 17) may be, for example, 100 μm to 1500 μm. The width w2 of the lower opening 55 in this embodiment may be, for example, 100 μm to 5000 μm. The width w3 of the upper opening 56 in this embodiment may be, similar to the width w2 of the lower opening 55 described above, for example, 100 μm to 5000 μm. However, the width w3 of the upper opening 56 may be different from the width w2 of the lower opening 55.

[0153] When viewed in a cross-section perpendicular to the X direction, each lower opening edge 55b is offset from the corresponding upper opening edge 56b. Each lower opening edge 55b is offset to the right from the corresponding upper opening edge 56b.

[0154] Similarly, in the portion of the first steam passage 51 extending in the Y direction, the center 55a of the lower opening 55 may be offset to one side in the X direction relative to the center 56a of the upper opening 56. In this case, each lower opening side edge 55b may be offset to one side relative to the corresponding upper opening side edge 56b.

[0155] The pair of wall projections 57 and 58 in this embodiment protrude diagonally toward each other. The first wall projection 57 protrudes toward the upper right. The second wall projection 58 protrudes toward the lower left.

[0156] In this embodiment, the first wall projection 57 is positioned offset in the Z direction from the intermediate position MP between the first main body surface 30a and the second main body surface 30b. The Z direction is the thickness direction of the wick sheet 30 and corresponds to the normal direction of the first main body surface 30a. As shown in Figure 17, the first wall projection 57 may be positioned closer to the first main body surface 30a than the intermediate position MP described above. In this case, the first wall projection 57 is positioned closer to the first main body surface 30a than to the second main body surface 30b. The distance s2 from the first main body surface 30a to the first wall projection 57 may be, for example, h1 or greater, and may be less than t4 / 2. h1 is the depth of the main groove 61 as described above. t4 is the thickness of the wick sheet 30 as described above.

[0157] Similarly, in this embodiment, the second wall projection 58 is positioned offset in the Z direction from the intermediate position MP between the first main body surface 30a and the second main body surface 30b. As shown in Figure 17, the second wall projection 58 may be positioned closer to the second main body surface 30b than the aforementioned intermediate position MP. In this case, the second wall projection 58 is positioned closer to the second main body surface 30b than to the first main body surface 30a. The distance s3 from the second main body surface 30b to the second wall projection 58 may be equal to the distance s2 from the first main body surface 30a to the first wall projection 57, or it may be different from the distance s2. The distance s3 may be, for example, h1 or greater, or less than t4 / 2.

[0158] Next, the manufacturing method of the vapor chamber 1 of this embodiment, which has the above configuration, will be explained with reference to Figures 18 to 23.

[0159] First, we will explain the wick sheet manufacturing process for creating the wick sheet 30.

[0160] First, as shown in Figure 18, a flat metal material sheet M is prepared as a material preparation step, including a lower surface Ma (an example of a first material surface) and an upper surface Mb (an example of a second material surface). The metal material sheet M may be formed from a rolled material having a desired thickness.

[0161] After the material preparation step, as shown in Figure 19, in the resist formation step, a lower resist film 70 is formed on the lower surface Ma of the metal material sheet M, and an upper resist film 71 is formed on the upper surface Mb. Before forming each resist film 70 and 71, the lower surface Ma and upper surface Mb of the metal material sheet M may be subjected to acidic degreasing as a pretreatment. Alternatively, each resist film 70 and 71 may be formed by applying a liquid resist to the lower surface Ma and upper surface Mb and drying and curing it. Or, each resist film 70 and 71 may be formed by attaching a dry film resist to the lower surface Ma and upper surface Mb.

[0162] Next, as shown in Figure 20, the lower resist film 70 and the upper resist film 71 are patterned by photolithography as a patterning step. In this case, a first resist opening 72 corresponding to the lower opening 55 is formed in the lower resist film 70, and a second resist opening 73 corresponding to the main channel groove 61 and connecting groove 65 of the liquid flow channel section 60 is formed. A third resist opening 74 corresponding to the upper opening 56 is formed in the upper resist film 71. The center of the first resist opening 72 is offset to one side in the Y direction relative to the center of the corresponding third resist opening 74. The Y-direction dimension w2' of the first resist opening 72 may be equal to or different from the Y-direction dimension w3' of the third resist opening 74. w2' is the dimension corresponding to the width w2 of the lower opening 55, and is the dimension set to form the width w2 of the lower opening 55 by etching. Similarly, w3' is a dimension corresponding to the width w3 of the lower opening 55, and is the dimension set to form the width w3 of the upper opening 56 by etching.

[0163] Next, as shown in Figure 21, the lower surface Ma and upper surface Mb of the metal material sheet M are etched as an etching process. This etches the portion of the lower surface Ma of the metal material sheet M corresponding to the first resist opening 72 and the second resist opening 73. As a result, the lower vapor channel recess 53 of the vapor channel section 50 and the main channel groove 61 and connecting groove 65 of the liquid channel section 60 are formed as shown in Figure 21. In addition, the portion of the upper surface Mb corresponding to the third resist opening 74 is etched to form the upper vapor channel recess 54 of the vapor channel section 50 as shown in Figure 21. For the etching solution, for example, an iron chloride-based etching solution such as an aqueous solution of ferric chloride, or a copper chloride-based etching solution such as an aqueous solution of copper chloride can be used.

[0164] Etching may be performed simultaneously on the lower surface Ma and upper surface Mb of the metal material sheet M. However, it is not limited to this, and the etching of the lower surface Ma and upper surface Mb may be performed as separate processes. Furthermore, the vapor channel section 50 and the liquid channel section 60 may be formed by etching simultaneously or in separate processes.

[0165] Furthermore, in the etching process, the lower surface Ma and upper surface Mb of the metal material sheet M are etched to obtain a predetermined outer contour shape of the wick sheet 30 as shown in Figures 6 and 7.

[0166] After the etching process, as shown in Figure 22, the lower resist film 70 and the upper resist film 71 are removed in a resist removal process.

[0167] In this way, the wick sheet 30 according to this embodiment is obtained.

[0168] Following the manufacturing process of the wick sheet 30, the lower sheet 10, the upper sheet 20, and the wick sheet 30 are joined together in a joining process, as shown in Figure 23. The lower sheet 10 and the upper sheet 20 may be formed from rolled material having a desired thickness.

[0169] More specifically, the lower sheet 10, wick sheet 30, and upper sheet 20 are first stacked in this order. In this case, the first main surface 30a of the wick sheet 30 is superimposed on the second lower sheet surface 10b of the lower sheet 10, and the first upper sheet surface 20a of the upper sheet 20 is superimposed on the second main surface 30b of the wick sheet 30. At this time, the alignment holes 12 of the lower sheet 10, the alignment holes 35 of the wick sheet 30, and the alignment holes 22 of the upper sheet 20 are used to align each sheet 10, 20, and 30.

[0170] Next, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are tack-fastened. For example, these sheets 10, 20, and 30 may be tack-fastened by spot resistance welding, or they may be tack-fastened by laser welding.

[0171] Next, the lower sheet 10, the wick sheet 30, and the upper sheet 20 are permanently joined by diffusion bonding. Diffusion bonding is a method of joining sheets 10, 20, and 30 by bringing the lower sheet 10 and the wick sheet 30 into close contact, and the wick sheet 30 and the upper sheet 20 into close contact. More specifically, each sheet 10, 20, and 30 is pressurized and heated in the stacking direction in a controlled atmosphere such as a vacuum or in an inert gas. This allows the sheets 10, 20, and 30 to be joined by utilizing the diffusion of atoms that occurs at the joining surface. Diffusion bonding heats the material of each sheet 10, 20, and 30 to a temperature close to its melting point, but lower than the melting point, thus avoiding melting and deformation of each sheet 10, 20, and 30. More specifically, the first main body surface 30a of the frame portion 32 and each land portion 33 of the wick sheet 30 is diffusion-bonded to the second lower sheet surface 10b of the lower sheet 10. Furthermore, the second main body surface 30b of the frame portion 32 and each land portion 33 of the wick sheet 30 is diffusion-bonded to the first upper sheet surface 20a of the upper sheet 20. In this way, the sheets 10, 20, and 30 are diffusion-bonded, and a sealed space 3 having a steam flow path portion 50 and a liquid flow path portion 60 is formed between the lower sheet 10 and the upper sheet 20. In the injection section 4 described above, the lower injection projection 11 of the lower sheet 10 and the wick sheet injection projection 36 of the wick sheet 30 are diffusion-bonded. The wick sheet injection projection 36 and the upper injection projection 21 of the upper sheet 20 are diffusion-bonded. As a result, the injection flow path 37 becomes a closed space.

[0172] After the joining process, the working fluid 2b is injected from the injection section 4 into the sealed space 3. During injection, the working fluid 2b is supplied to the sealed space 3 by passing through the injection channel 37.

[0173] Subsequently, the injection channel 37 described above is sealed. For example, the injection section 4 may be partially melted to seal the injection channel 37. This blocks communication between the sealed space 3 and the outside, sealing the working fluid 2b into the sealed space 3 and preventing the working fluid 2b from leaking out of the sealed space 3. After sealing, the injection section 4 may be cut.

[0174] As described above, the vapor chamber 1 according to this embodiment is obtained.

[0175] The operation of the vapor chamber 1 according to this embodiment will be described below.

[0176] The working fluid 2b adhering to the walls 53a, 53b, 54a, and 54b of each vapor channel recess 53 and 54 can also be transported to the evaporation region SR by the capillary action of the vapor channel recesses 53 and 54. Although the vapor channel recesses 53 and 54 primarily function as channels for working steam 2a, the working fluid 2b adhering to the walls 53a, 53b, 54a, and 54b can also be subjected to capillary action. When viewed in a cross-section perpendicular to the X direction, if the length of the walls 53a, 53b, 54a, and 54b is short, the capillary action applied to the working fluid 2b adhering to the walls 53a, 53b, 54a, and 54b can be increased. The length of the wall refers to the length along the wall when viewed in a cross-section perpendicular to the X direction.

[0177] As shown in Figure 17, in this embodiment, the first wall projection 57 is positioned closer to the first body surface 30a than the intermediate position MP between the first body surface 30a and the second body surface 30b in the Z direction. In this case, the length of the lower wall surface 53a connected to the first wall projection 57 is shortened, and the capillary action applied to the working fluid 2b adhering to the lower wall surface 53a is enhanced.

[0178] On the other hand, when viewed in a cross-section perpendicular to the X direction, the length of the upper wall surface 54a connected to the first wall projection 57 increases. In this case, the effect of the upper wall surface 54a in holding the working fluid 2b is enhanced, and the amount of working fluid 2b held by the upper wall surface 54a can increase. The working fluid 2b held by the upper wall surface 54a moves beyond the first wall projection 57 to the lower wall surface 53a and is transported to the evaporation region SR by the capillary action of the lower wall surface 53a. Therefore, the amount of working fluid 2b transported to the evaporation region SR can be increased by the working fluid 2b held by the upper wall surface 54a.

[0179] The lower wall surface 53a is connected to the first main body surface 30a, and the main channel groove 61 and connecting groove 65 of the liquid flow channel section 60 are provided on the first main body surface 30a. In this case, the lower wall surface 53a and the liquid flow channel section 60 are close together, and the working fluid 2b can move between the lower wall surface 53a and the liquid flow channel section 60.

[0180] Similarly, in this embodiment, the second wall projection 58 is positioned closer to the second body surface 30b than to the intermediate position MP between the first body surface 30a and the second body surface 30b in the Z direction. In this case, the length of the upper wall surface 54b connected to the second wall projection 58 is shortened, and the capillary action applied to the working fluid 2b adhering to the upper wall surface 54b is enhanced.

[0181] On the other hand, when viewed in a cross-section perpendicular to the X direction, the length of the lower wall surface 53b connected to the second wall surface projection 58 increases. In this case, the effect of the lower wall surface 53b in holding the working fluid 2b is enhanced, and the amount of working fluid 2b held by the lower wall surface 53b can increase. The working fluid 2b held by the lower wall surface 53b moves beyond the second wall surface projection 58 to the upper wall surface 54b and is transported to the evaporation region SR by the capillary action of the upper wall surface 54b. Therefore, the amount of working fluid 2b transported to the evaporation region SR can be increased by the working fluid 2b held by the lower wall surface 53b.

[0182] The lower wall surface 53b is connected to the first main body surface 30a, and the first main body surface 30a is provided with the main channel groove 61 and the connecting groove 65 of the liquid flow channel section 60. In this case, the lower wall surface 53b and the liquid flow channel section 60 are brought closer together, and the working fluid 2b held by the lower wall surface 53b can move to the liquid flow channel section 60. This also increases the amount of working fluid 2b transported to the evaporation region SR.

[0183] In this way, the working fluid 2b can be transported to the evaporation region SR not only by the liquid flow path section 60 but also by the vapor flow path section 50.

[0184] As described above, according to this embodiment, the lower wall surface 53a of the lower steam flow recess 53 and the upper wall surface 54a of the upper steam flow recess 54 are connected by a first wall projection 57. The first wall projection 57 protrudes toward the inside of the steam flow section 50 and is positioned offset in the Z direction from the intermediate position MP between the first main body surface 30a and the second main body surface 30b. This makes it possible to make the lengths of the lower wall surface 53a and the upper wall surface 54a different when viewed in a cross section perpendicular to the X direction. Therefore, the capillary action applied to the working fluid 2b adhering to the shorter of the two wall surfaces 53a and 54a can be enhanced, and the holding action of the working fluid 2b held by the longer wall surface can be enhanced. For example, when the length of the lower wall surface 53a is short, the working fluid 2b held by the upper wall surface 54a can be transported to the evaporation region SR by the capillary action of the lower wall surface 53a. Therefore, the amount of working fluid 2b transported to the evaporation region SR can be increased. As a result, the heat dissipation efficiency of the vapor chamber 1 can be improved, and the cooling efficiency of the electronic device D can be improved.

[0185] Furthermore, according to this embodiment, the first main body surface 30a is provided with a liquid flow channel section 60 including a plurality of main channel grooves 61 and a plurality of connecting grooves 65, and the first wall projection 57 is positioned closer to the first main body surface 30a than the intermediate position MP between the first main body surface 30a and the second main body surface 30b. This allows the first wall projection 57 to be brought closer to the liquid flow channel section 60. As a result, the capillary action applied to the working fluid 2b adhering to the lower wall surface 53a near the liquid flow channel section 60 can be enhanced, and the working fluid 2b can move between the lower wall surface 53a and the liquid flow channel section 60. In this case, the working fluid 2b can be collected in the area with stronger capillary action between the lower wall surface 53a and the liquid flow channel section 60, and the amount of working fluid 2b transported to the evaporation region SR can be increased.

[0186] Furthermore, according to this embodiment, the lower wall surface 53b of the lower steam flow recess 53 and the upper wall surface 54b of the upper steam flow recess 54 are connected by a second wall projection 58. The second wall projection 58 protrudes toward the inside of the steam flow section 50 and is positioned offset in the Z direction from the intermediate position MP between the first main body surface 30a and the second main body surface 30b. This makes it possible to make the lengths of the lower wall surface 53b and the upper wall surface 54b different when viewed in a cross section perpendicular to the X direction. Therefore, the capillary action applied to the working fluid 2b adhering to the shorter of the two wall surfaces 53b and 54b can be enhanced, and the holding action of the working fluid 2b held by the longer wall surface can be enhanced. For example, if the length of the upper wall surface 54b is short, the working fluid 2b held by the lower wall surface 53b can be transported to the evaporation region SR by the capillary action of the upper wall surface 54b. Therefore, the amount of working fluid 2b transported to the evaporation region SR can be increased. As a result, the heat dissipation efficiency of the vapor chamber 1 can be improved, and the cooling efficiency of the electronic device D can be improved.

[0187] Furthermore, according to this embodiment, the center 55a of the lower opening 55 of the vapor flow path 50 located on the first main surface 30a of the wick sheet 30 is offset from the center 56a of the upper opening 56 located on the second main surface 30b. This allows the first wall projection 57 and the second wall projection 58 to be easily offset from the intermediate position MP between the first main surface 30a and the second main surface 30b. As a result, the amount of working fluid 2b transported to the evaporation region SR can be easily increased. Also, when the center 55a of the lower opening 55 is offset from the center 56a of the upper opening 56, the difference between the width w2 of the lower opening 55 and the width w3 of the upper opening 56 can be reduced. In this case, it is possible to suppress the bias in the holding action of the working fluid 2b by the lower wall surface 53b and the holding action of the working fluid 2b by the upper wall surface 54a. As a result, the performance of the vapor chamber 1 can be suppressed from being affected by the posture of the vapor chamber 1, and the reliability of the vapor chamber 1 can be improved.

[0188] In the embodiment described above, an example was described in which the first wall projection 57 is positioned closer to the first main body surface 30a than the intermediate position MP, and the second wall projection 58 is positioned closer to the second main body surface 30b than the intermediate position MP. However, the embodiment is not limited to this. For example, the first wall projection 57 may be positioned closer to the second main body surface 30b than the intermediate position MP, and the second wall projection 58 may be positioned closer to the first main body surface 30a than the intermediate position MP. In this case, the second wall projection 58 can be brought closer to the fluid flow path 60, and the working fluid 2b can move between the lower wall surface 53b and the fluid flow path 60. Alternatively, the second wall projection 58 may be positioned at the intermediate position MP.

[0189] Alternatively, as shown in Figure 24, the first wall projection 57 may be positioned closer to the first main body surface 30a than the intermediate position MP, and the second wall projection 58 may be positioned closer to the first main body surface 30a than the intermediate position MP.

[0190] For example, in the etching process shown in Figure 21, the first resist opening 72 can be formed to reduce the etching rate of the lower vapor channel recess 53, thereby forming the first wall protrusion 57 and the second wall protrusion 58 shown in Figure 24. In Figure 24, the distance s4 from the first main body surface 30a to the first wall protrusion 57 may be, for example, 20 μm or more. For example, the distance s4 may be less than t4 / 2 and less than or equal to h1. The distance s5 from the first main body surface 30a to the second wall protrusion 58 may be equal to the distance s4 or different from the distance s4. For example, the distance s5 may be less than t4 / 2 and less than or equal to h1.

[0191] In the modified configuration shown in Figure 24, the first wall projection 57 is positioned closer to the first main body surface 30a than the intermediate position MP, and the second wall projection 58 is also positioned closer to the first main body surface 30a than the intermediate position MP. This allows the first wall projection 57 and the second wall projection 58 to be brought closer to the liquid flow channel 60. As a result, the capillary action applied to the working fluid 2b adhering to the lower wall surfaces 53a and 53b near the liquid flow channel 60 can be enhanced. In this case, the working fluid 2b can move back and forth between the lower wall surface 53a and the liquid flow channel 60, and also between the lower wall surface 53b and the liquid flow channel 60. Therefore, the working fluid 2b can be concentrated in areas of the lower wall surface 53a, lower wall surface 53b, and liquid flow channel 60 where the capillary action is strong, thereby increasing the amount of working fluid 2b transported to the evaporation region SR.

[0192] Furthermore, according to the modified example shown in Figure 24, the first wall projection 57 is positioned closer to the first main body surface 30a than the intermediate position MP, and the second wall projection 58 is also positioned closer to the first main body surface 30a than the intermediate position MP. This allows the flow path of the working steam 2a diffusing within the upper steam flow path recess 54 to be made closer to a large circular shape. As a result, the flow resistance of the working steam 2a can be reduced, and the working steam 2a can diffuse easily. This improves the heat dissipation efficiency of the vapor chamber 1 and improves the cooling efficiency of the electronic device D.

[0193] Furthermore, in the embodiment described above, an example was described in which the lower wall surface 53b of the lower steam flow recess 53 and the upper wall surface 54b of the upper steam flow recess 54 are connected by a second wall projection 58. However, the embodiment is not limited to this. For example, as shown in Figure 25, the lower wall surface 53b and the upper wall surface 54b may be formed in a continuous concave shape from the lower wall surface 53b to the upper wall surface 54b. In this case, the lower wall surface 53b and the upper wall surface 54b may be formed to bulge outwards from the steam flow recesses 53 and 54. For example, the lower wall surface 53b and the upper wall surface 54b may be formed to bulge outwards from the steam flow recesses 53 and 54 beyond the straight line connecting the right lower opening edge 55b and the right upper opening edge 56b shown in Figure 25. The lower wall surface 53b and the upper wall surface 54b may be continuously and smoothly curved.

[0194] For example, in the etching process shown in Figure 21, the etching rate of the portion of the lower vapor channel recess 53 on the lower wall surface 53b side may be increased relative to the etching rate of the portion on the lower wall surface 53a side. For example, the first resist opening 72 may be formed so as to decrease the etching rate of the portion of the lower vapor channel recess 53 on the lower wall surface 53a side. This makes it possible to increase the etching rate of the portion of the lower vapor channel recess 53 on the lower wall surface 53b side compared to the etching rate of the portion on the lower wall surface 53a side. Similarly, the third resist opening 74 may be formed so as to decrease the etching rate of the portion of the upper vapor channel recess 54 on the upper wall surface 54a side. This makes it possible to increase the etching rate of the portion of the upper vapor channel recess 54 on the upper wall surface 54b side compared to the etching rate of the portion on the upper wall surface 54a side. In this way, the lower wall surface 53b and the upper wall surface 54b are formed so as not to form the second wall surface protrusion 58. As a result, the lower wall surface 53b and the upper wall surface 54b are formed in a continuous concave shape from the lower wall surface 53b to the upper wall surface 54b.

[0195] As shown in the modified example in Figure 25, the lower wall surface 53b and the upper wall surface 54b are formed in a continuous concave shape from the lower wall surface 53b to the upper wall surface 54b. This makes the flow path of the working steam 2a diffusing within the steam flow path recesses 53 and 54 closer to a large circular shape. As a result, the flow resistance of the working steam 2a can be reduced, and the working steam 2a can diffuse easily. This improves the heat dissipation efficiency of the vapor chamber 1 and improves the cooling efficiency of the electronic device D.

[0196] (Third embodiment) Next, with reference to Figures 26 to 35, the main body sheet for the vapor chamber, the vapor chamber, and the electronic equipment in the third embodiment of the present invention will be described.

[0197] In the third embodiment shown in Figures 26 to 35, the second main body surface is provided with third spatial recesses located on both sides of the second spatial recess. A pair of third wall projections, connecting each of the wall surfaces of the second spatial recess to the corresponding third wall surface of the third spatial recess, protrude toward the second main body surface. These are the main differences. The other configurations are substantially the same as those of the second embodiment shown in Figures 16 to 25. In Figures 26 to 35, the same reference numerals are used for parts identical to those in the second embodiment shown in Figures 16 to 25, and detailed descriptions are omitted.

[0198] In this embodiment, as shown in Figure 26, the vapor chamber 1 of the steam flow channel section 50 has a first steam passage 51 and a second steam passage 52, each having a lower steam flow channel recess 53, a first upper steam flow channel recess 81 and a second upper steam flow channel recess 82, respectively. The lower steam flow channel recess 53 is an example of a first spatial recess and is provided on the first main body surface 30a. The first upper steam flow channel recess 81 is an example of a second spatial recess and is provided on the second main body surface 30b. The second upper steam flow channel recess 82 is an example of a third spatial recess and is provided on the second main body surface 30b. The first upper steam flow channel recess 81 has a pair of first upper wall surfaces 81a and 81b. The first upper wall surfaces 81a and 81b are examples of second wall surfaces. The first upper wall surface 81a is the left wall surface in Figure 26, and the first upper wall surface 81b is the right wall surface in Figure 26. In this embodiment, the first upper steam flow channel recess 81 and the first upper wall surfaces 81a and 81b are substantially the same as the upper steam flow channel recess 54 and the upper wall surfaces 54a and 54b shown in Figure 16, etc. Therefore, a detailed explanation of the first upper steam flow channel recess 81 and the first upper wall surfaces 81a and 81b will be omitted.

[0199] As shown in Figure 26, when viewed in a cross-section perpendicular to the X direction, the second upper steam flow recess 82 is located on both sides of the first upper steam flow recess 81. Each second upper steam flow recess 82 communicates with the first upper steam flow recess 81 and forms a continuous opening in the second main body surface 30b.

[0200] The second upper steam passage recess 82 is formed in a concave shape on the second main body surface 30b of the wick sheet 30 by etching from the second main body surface 30b in the second etching process described later. As a result, the second upper steam passage recess 82 has a curved second upper wall surface 82a, as shown in Figure 26. The second upper wall surface 82a is an example of a third wall surface. This second upper wall surface 82a defines the second upper steam passage recess 82 and constitutes part of the first steam passage 51 and part of the second steam passage 52.

[0201] The upper opening 83 in the present embodiment is located on the second main body surface 30b and is an opening of the first upper vapor flow path recess 81 and the second upper vapor flow path recess 82 on the second main body surface 30b. As shown in FIG. 6, the planar shape of the upper opening 83 in the first vapor passage 51 is in the shape of a rectangular frame. As shown in FIG. 6, the planar shape of the upper opening 83 in the second vapor passage 52 is in the shape of an elongated rectangle. The upper opening 83 is an opening defined by the first upper vapor flow path recess 81 and the second upper vapor flow path recess 82 on the second main body surface 30b.

[0202] The width w8 of the upper opening 83 may be, for example, 200 μm to 6000 μm. Here, the width w8 of the upper opening 83 is the dimension of the upper opening 83 in the Y direction. The width w8 of the upper opening 83 corresponds to the dimension in the Y direction of the portion of the first vapor passage 51 that extends in the X direction and also corresponds to the dimension in the Y direction in the second vapor passage 52. In the present embodiment, the dimension in the Y direction between the second upper wall surfaces 82a of the pair of second upper vapor flow path recesses 82 that define the vapor passages 51 and 52 gradually increases from the first main body surface 30a toward the second main body surface 30b and is maximum on the second main body surface 30b. Therefore, the width w8 is the maximum value of the dimension in the Y direction between the pair of second upper wall surfaces 82a. However, the dimension in the Y direction between the pair of second upper wall surfaces 82a may not be maximum on the second main body surface 30b. For example, the position where the dimension in the Y direction between the pair of second upper wall surfaces 82a is maximum may be closer to the first main body surface 30a than the second main body surface 30b. Note that the width w8 also corresponds to the dimension in the X direction of the portion of the first vapor passage 51 that extends in the Y direction. Also, the width w8 of the upper opening 83 may be larger than the width w2 of the lower opening 55. Also in the present embodiment, the upper opening 83 may extend from the region 56c that overlaps the lower opening 55 in plan view to the position that overlaps the main flow groove 61 in plan view.

[0203] In the present embodiment, the cross-sectional shapes of the first vapor passage 51 and the second vapor passage 52 may be symmetrical in the Y direction. That is, the center 55a of the lower opening 55 may be arranged at the same position in the Y direction with respect to the center 83a of the upper opening 83.

[0204] The upper opening 83 is defined by a pair of upper opening side edges 83b (an example of the second opening side edge) extending in the X direction. The center 83a of the upper opening 83 described above is the midpoint of the pair of upper opening side edges 83b when viewed in a cross-section perpendicular to the X direction. In FIG. 26, the upper opening side edge 83b is shown as the intersection of the second main body surface 30b and the second upper wall surface 82a of the second upper vapor flow path recess 82, and the midpoint of these intersections is the center 83a of the upper opening 83.

[0205] Each upper opening side edge 83b is arranged offset to one side with respect to the corresponding lower opening side edge 55b. In FIG. 26, the upper opening side edge 83b on the right side of the upper opening 83 is arranged offset to the right with respect to the lower opening side edge 55b on the right side of the lower opening 55, and the upper opening side edge 83b on the left side is arranged offset to the left with respect to the lower opening side edge 55b on the left side. In this way, the width w8 of the upper opening 83 is larger than the width w2 of the lower opening 55.

[0206] In the present embodiment, the first upper wall surfaces 81a and 81b of the first upper vapor flow path recess 81 do not extend to the second main body surface 30b. The width w9 of the opening when the first upper wall surfaces 81a and 81b are extended to the second main body surface 30b along the curved shape of the first upper wall surfaces 81a and 81b may be equal to the width w3 of the upper opening 56 shown in FIG. 17. That is, in the first patterning step described later, the third resist opening 94 formed in the first upper resist film 91 formed on the second main body surface 30b may be equal to the first resist opening 92 formed in the first lower resist film 90 formed on the first main body surface 30a.

[0207] As shown in Figure 26, the first upper wall surfaces 81a and 81b of the first upper steam flow recess 81 and the corresponding second upper wall surface 82a of the second upper steam flow recess 82 are connected by a third wall projection 84. As a result, the first upper wall surfaces 81a and 81b do not extend to the second main body surface 30b, and the first upper steam flow recess 81 communicates with the second upper steam flow recess 82 on its side.

[0208] The third wall projection 84 may project toward the second main body surface 30b. The third wall projection 84 may be formed to extend toward the upper sheet 20. The third wall projection 84 is located closer to the first main body surface 30a than to the second main body surface 30b and spaced apart from the first upper sheet surface 20a of the upper sheet 20.

[0209] The lower wall surfaces 53a and 53b of the lower steam flow recess 53 and the corresponding first upper wall surfaces 81a and 81b of the first upper steam flow recess 81 are connected by wall protrusions 57 and 58. More specifically, the lower wall surface 53a of the lower steam flow recess 53 and the corresponding first upper wall surface 81a of the first upper steam flow recess 81 are connected by a first wall protrusion 57. The lower wall surface 53b of the lower steam flow recess 53 and the corresponding first upper wall surface 81b of the first upper steam flow recess 81 are connected by a second wall protrusion 58. The first wall protrusion 57 is the left wall protrusion in Figure 26, and the second wall protrusion 58 is the right wall protrusion in Figure 26.

[0210] As shown in Figure 26, the first wall projection 57 may be positioned at an intermediate position MP between the first main body surface 30a and the second main body surface 30b. The second wall projection 58 may be positioned at an intermediate position MP between the first main body surface 30a and the second main body surface 30b.

[0211] A penetration 34 is defined by a pair of wall projections 57 and 58, and within the penetration 34, the lower steam flow recess 53 and the first upper steam flow recess 81 are in communication with each other. The width w10 of such a penetration 34 (see Figure 26) may be, for example, 400 μm to 1600 μm. Here, the width w10 of the penetration 34 corresponds to the gap between adjacent land portions 33 in the Y direction. More specifically, the width w10 means the distance in the Y direction between the tip of the first wall projection 57 and the tip of the second wall projection 58 that define the penetration 34.

[0212] Furthermore, the width w11 of the land portion 33 in this embodiment (see Figure 26) may be, for example, 100 μm to 1500 μm. Here, the width w11 of the land portion 33 is the maximum dimension of the land portion 33 in the Y direction. More specifically, the width w11 of the land portion 33 means the distance in the Y direction between the tip of the first wall projection 57 that defines the land portion 33 and the tip of the second wall projection 58.

[0213] Next, the manufacturing method of the vapor chamber 1 of this embodiment, which has the above configuration, will be explained with reference to Figures 27 to 34. Here, we will mainly explain the differences from the second embodiment.

[0214] Following the material preparation steps shown in Figure 18, as shown in Figure 27, a first resist formation step is performed in which a first lower resist film 90 is formed on the lower surface Ma of the metal material sheet M, and a first upper resist film 91 is formed on the upper surface Mb. The first resist formation step may be performed in the same manner as the resist formation step shown in Figure 19.

[0215] Next, as shown in Figure 28, in the first patterning step, the first lower resist film 90 and the first upper resist film 91 are patterned by photolithography. In this case, a first resist opening 92 corresponding to the lower opening 55 is formed in the first lower resist film 90, and a second resist opening 93 corresponding to the main channel groove 61 and connecting groove 65 of the liquid flow channel section 60 is formed. In addition, a third resist opening 94 corresponding to the upper opening 83 is formed in the first upper resist film 91. The Y-direction dimension w9' of the third resist opening 94 is the dimension corresponding to the width w9 shown in Figure 26, and is the dimension set in order to form the width w9 by etching. w9' may be equal to or different from the Y-direction dimension w3' of the first resist opening 92.

[0216] Next, as shown in Figure 29, in the first etching step, the lower surface Ma and upper surface Mb of the metal material sheet M are etched in the same manner as the etching step shown in Figure 21. As a result, the lower steam channel recess 53 of the steam channel section 50, and the main channel groove 61 and connecting groove 65 of the liquid channel section 60 are formed on the lower surface Ma of the metal material sheet M, as shown in Figure 29. In addition, the first upper steam channel recess 81 of the steam channel section 50 is formed on the upper surface Mb.

[0217] After the first etching step, as shown in Figure 30, the first resist removal step involves removing the first lower resist film 90 and the first upper resist film 91.

[0218] After the first resist removal step, as shown in Figure 31, in the second resist formation step, a second lower resist film 95 is formed on the lower surface Ma of the metal material sheet M, and a second upper resist film 96 is formed on the upper surface Mb. In addition, wall resist films 97 are formed on the lower wall surfaces 53a, 53b of the lower vapor channel recess 53 and the first upper wall surfaces 81a, 81b of the first upper vapor channel recess 81. The second lower resist film 95, the second upper resist film 96, and the wall resist film 97 may be formed using liquid resist. In this case, the wall resist film 97 can be easily formed on the lower wall surfaces 53a, 53b and the first upper wall surfaces 81a, 81b. Before forming each of the resist films 95 to 97, the lower surface Ma and upper surface Mb of the metal material sheet M, as well as each of the wall surfaces 53a, 53b, 81a, 81b, may be subjected to acidic degreasing treatment as a pretreatment.

[0219] Next, as shown in Figure 32, as a second patterning step, the second upper resist film 96 and the wall resist film 97 are patterned by photolithography. In this case, a fourth resist opening 98 corresponding to the second upper vapor channel recess 82 is formed in the second upper resist film 96 and the wall resist film 97. The fourth resist opening 98 is formed to extend from the second upper resist film 96 to the wall resist film 97. The fourth resist opening 98 may be formed such that the opening edge opposite to the first upper vapor channel recess 81 satisfies a dimension w8' in the Y direction, as shown in Figure 32. w8' is a dimension corresponding to the width w8 of the upper opening 83, and is set to form the width w8 of the upper opening 83 by etching.

[0220] Next, as shown in Figure 33, in the second etching step, the upper surface Mb of the metal material sheet M and the first upper wall surfaces 81a and 81b of the first upper steam channel recess 81 are etched, similar to the etching step shown in Figure 21. As a result, the second upper steam channel recess 82 of the steam channel section 50 is formed on the upper surface Mb of the metal material sheet M and the first upper wall surfaces 81a and 81b.

[0221] After the second etching process, as shown in FIG. 34, as the second resist removal process, the second lower resist film 95 and the second upper resist film 96 are removed.

[0222] In this way, the wick sheet 30 according to the present embodiment is obtained.

[0223] According to the present embodiment as described above, the first upper side wall surfaces 81a and 81b of the first upper steam flow path recess 81 and the second upper side wall surface 82a of the second upper steam flow path recess 82 located on both sides of the first upper steam flow path recess 81 are connected by the third wall surface protruding portion 84. The third wall surface protruding portion 84 protrudes toward the second main body surface 30b. As a result, it is possible to suppress the second upper side sheet surface 20b of the upper sheet 20 from being deformed into a concave shape. That is, a part of the upper sheet 20 that overlaps the upper opening 83 receives the atmospheric pressure on the second upper side sheet surface 20b, and thus may enter the first upper steam flow path recess 81 and the second upper steam flow path recess 82 of the decompressed steam flow path portion 50. In this case, it is possible to suppress the relevant part of the upper sheet 20 from entering deeper than the third wall surface protruding portion 84. Therefore, it is possible to suppress the second upper side sheet surface 20b of the upper sheet 20 from being deformed into a concave shape. In this case, the adhesion between the electronic device D and the lower sheet 10 can be improved, and the thermal resistance between the electronic device D and the vapor chamber 1 can be reduced.

[0224] In the above-described present embodiment, an example in which the first wall surface protruding portion 57 and the second wall surface protruding portion 58 are arranged at an intermediate position MP between the first main body surface 30a and the second main body surface 30b in the Z direction has been described. However, it is not limited to this.

[0225] For example, as shown in FIG. 35, the first wall surface protruding portion 57 may be arranged offset with respect to the intermediate position MP in the Z direction. In FIG. 35, the first wall surface protruding portion 57 is arranged closer to the first main body surface 30a than the intermediate position MP. The distance s2 from the first main body surface 30a to the first wall surface protruding portion 57 may be the same as the distance s2 shown in FIG. 17.

[0226] As shown in Figure 35, the second wall projection 58 may be positioned offset from the intermediate position MP in the Z direction. In Figure 35, the second wall projection 58 is positioned closer to the second main body surface 30b than to the intermediate position MP. The distance s3 from the second main body surface 30b to the second wall projection 58 may be the same as the distance s3 shown in Figure 17.

[0227] In the modified example shown in Figure 35, the first wall projection 57 and the second wall projection 58 are arranged in the same manner as in the example shown in Figure 17. In this case, the cross-sectional shapes of the first steam passage 51 and the second steam passage 52 may be asymmetrical in the Y direction.

[0228] In Figure 35, the center 55a of the lower opening 55 is offset to one side in the Y direction relative to the center 83a of the upper opening 83. Although Figure 35 shows an example where the lower opening 55 is offset to the right relative to the upper opening 83, it may also be offset to the left. The amount of offset between the center 55a of the lower opening 55 and the center 83a of the upper opening 83 may be equal to the amount of offset s1 shown in Figure 17.

[0229] In Figure 35, the right upper opening edge 83b of the upper opening 83 is positioned to the right of the right lower opening edge 55b of the lower opening 55, and the left upper opening edge 83b is positioned to the left of the left lower opening edge 55b. In this way, the width w8 of the upper opening 83 is greater than the width w2 of the lower opening 55. However, if the width w8 of the upper opening 83 is greater than the width w2 of the lower opening 55, the right upper opening edge 83b of the upper opening 83 may be positioned to the left of the right lower opening edge 55b of the lower opening 55. Alternatively, in this case, the right upper opening edge 83b of the upper opening 83 may be positioned at the same location as the right lower opening edge 55b.

[0230] (Fourth embodiment) Next, the main body sheet, vapor chamber, and electronic equipment for the fourth embodiment of the present invention will be described with reference to Figures 36 to 47.

[0231] In the fourth embodiment shown in Figures 36 to 47, the main difference is that the first wall end located on the side of the first main body surface is located inside the steam flow path section in a plan view, relative to the projection. The other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 17. In Figures 36 to 47, the same reference numerals are used for parts identical to those in the first embodiment shown in Figures 1 to 17, and detailed descriptions are omitted.

[0232] The vapor chamber 100 according to this embodiment will now be described. As shown in Figures 36 and 37, the vapor chamber 100 has a sealed space 103 in which working fluids 2a and 2b are sealed. The electronic device D of the electronic device E described above is effectively cooled by the repeated phase changes of the working fluids 2a and 2b in the sealed space 103.

[0233] As shown in Figures 36 and 37, the vapor chamber 100 comprises a lower sheet 110, an upper sheet 120, and a wick sheet 130 for the vapor chamber. The wick sheet 130 for the vapor chamber will hereinafter simply be referred to as the wick sheet 130. In this embodiment, the vapor chamber 100 has the lower sheet 110, the wick sheet 130, and the upper sheet 120 stacked in this order.

[0234] The vapor chamber 100 is generally formed in the shape of a thin flat plate. The planar shape of the vapor chamber 100 is arbitrary, but it may be rectangular as shown in Figure 36. The planar shape of the vapor chamber 100 may be, for example, a rectangle with one side of 50 mm to 200 mm and the other side of 150 mm to 60 mm, or a square with one side of 70 mm to 300 mm. The planar dimensions of the vapor chamber 100 are arbitrary. In this embodiment, as an example, an example in which the planar shape of the vapor chamber 100 is rectangular with the X direction as the longitudinal direction, as described later, will be explained. In this case, as shown in Figures 38 to 41, the lower sheet 110, the upper sheet 120, and the wick sheet 130 may have the same planar shape as the vapor chamber 100. Furthermore, the planar shape of the vapor chamber 100 is not limited to a rectangular shape, but may be any shape such as a circle, an ellipse, an L-shape, or a T-shape.

[0235] As shown in Figure 36, the vapor chamber 100 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.

[0236] The evaporation region SR is the region that overlaps with the electronic device D in a plan view, and is the region where the electronic device D is mounted. The evaporation region SR may be located anywhere in the vapor chamber 100. In this embodiment, the evaporation region SR is formed on one side of the vapor chamber 100 in the X direction (the left side in Figure 36). Heat from the electronic device D is transferred to the evaporation region SR, and this heat causes the working fluid 2b to evaporate in the evaporation region SR. The heat from the electronic device D can be transferred not only to the region that overlaps with the electronic device D in a plan view, but also to the surrounding area of ​​that region. Therefore, the evaporation region SR includes the region that overlaps with the electronic device D and the surrounding area in a plan view. Here, a plan view may refer to a view of the vapor chamber 100 from a direction perpendicular to the surface that receives heat from the electronic device D and the surface that releases the received heat. The surface that receives heat corresponds to the second upper sheet surface 120b of the upper sheet 120, which will be described later. The heat-releasing surface corresponds to the first lower sheet surface 110a of the lower sheet 110, which will be described later. For example, as shown in Figure 36, a view of the vapor chamber 100 from above or from below corresponds to a plan view.

[0237] The condensation region CR is a region that does not overlap with the electronic device D in a plan view, and is primarily a region where the working vapor 2a releases heat and condenses. The condensation region CR may also be the region surrounding the evaporation region SR. In the condensation region CR, heat from the working vapor 2a is released to the lower sheet 110, and the working vapor 2a is cooled and condenses in the condensation region CR.

[0238] Furthermore, when the vapor chamber 100 is installed inside a mobile terminal, the top-bottom relationship may be disrupted depending on the orientation of the mobile terminal. However, for convenience, in this embodiment, the sheet that receives heat from the electronic device D is referred to as the upper sheet 120, and the sheet that releases the received heat is referred to as the lower sheet 110. For this reason, the following explanation will be given with the lower sheet 110 positioned at the bottom and the upper sheet 120 positioned at the top.

[0239] As shown in Figure 37, the lower sheet 110 is an example of a first sheet. The lower sheet 110 has a first lower sheet surface 110a located on the opposite side from the wick sheet 130, and a second lower sheet surface 110b located on the opposite side from the first lower sheet surface 110a. The second lower sheet surface 110b is located on the side of the wick sheet 130. The lower sheet 110 may be formed to be flat overall, and the lower sheet 110 may have a uniform thickness overall. A housing member Ha, which constitutes part of the housing of a mobile terminal or the like, may be attached to this first lower sheet surface 110a. The entire first lower sheet surface 110a may be covered by the housing member Ha. As shown in Figure 38, alignment holes 112 may be provided at the four corners of the lower sheet 110.

[0240] As shown in Figure 37, the upper sheet 120 is an example of a second sheet. The upper sheet 120 has a first upper sheet surface 120a located on the side of the wick sheet 130, and a second upper sheet surface 120b located on the opposite side of the first upper sheet surface 120a. The upper sheet 120 may be formed to be flat overall, and the upper sheet 120 may have a uniform thickness overall. The electronic device D described above may be attached to this second upper sheet surface 120b. As shown in Figure 39, alignment holes 122 may be provided at the four corners of the upper sheet 120.

[0241] As shown in Figure 37, the wick sheet 130 is an example of a main sheet. The wick sheet 130 includes a steam passage section 150 and a liquid passage section 160 arranged adjacent to the steam passage section 150. The wick sheet 130 also has a first main surface 131a and a second main surface 131b located on the opposite side from the first main surface 131a. The first main surface 131a is located on the side of the lower sheet 110, and the second main surface 131b is located on the side of the upper sheet 120.

[0242] The second lower sheet surface 110b of the lower sheet 110 and the first main body surface 131a of the wick sheet 130 may be permanently joined to each other by diffusion bonding. Similarly, the first upper sheet surface 120a of the upper sheet 120 and the second main body surface 131b of the wick sheet 130 may be permanently joined to each other by diffusion bonding. Note that the lower sheet 110, upper sheet 120, and wick sheet 130 may be joined by other methods such as brazing, as long as they can be permanently joined, rather than by diffusion bonding.

[0243] As shown in Figures 37, 40, and 41, the wick sheet 130 according to this embodiment has a frame portion 132 formed in the shape of a rectangular frame in plan view, and land portions 133 provided within the frame portion 132. The frame portion 132 and each land portion 133 extend from the first main body surface 131a to the second main body surface 131b. The frame portion 132 and the land portions 133 are parts of the wick sheet 130 where the material remains without being etched in the etching process described later. In this embodiment, the frame portion 132 is formed in the shape of a rectangular frame in plan view. A steam flow path portion 150 is defined inside the frame portion 132. Operating steam 2a flows inside the frame portion 132, around the land portions 133.

[0244] In this embodiment, the land portion 133 may extend in an elongated shape with the X direction as the longitudinal direction in a plan view. The planar shape of the land portion 133 may be an elongated rectangular shape. Each land portion 133 may be spaced equally apart in the Y direction and arranged parallel to each other. Working steam 2a flows around each land portion 133 and is transported toward the condensation region CR. This prevents obstruction of the flow of working steam 2a. The width w21 of the land portion 133 (see Figure 42) may be, for example, 36 μm or more and 4000 μm or less. Here, the width w21 of the land portion 133 is the dimension of the land portion 133 in the Y direction, and means the dimension at the widest position of the land portion 133 (for example, the position where the first wall end portion 153b, described later, is located).

[0245] The frame portion 132 and each land portion 133 are diffusion-bonded to the lower sheet 110 and also to the upper sheet 120. This improves the mechanical strength of the vapor chamber 100. The first wall surface 153a, the second wall surface 154a, and the projection 155 of the steam passage 151, which will be described later, constitute the side walls of the land portion 133. The first wall surface 153a, the second wall surface 154a, and the projection 155 are formed on both sides of each land portion 133 in the width direction (X direction), respectively. The cross-sectional shape along the width direction (X direction) of each land portion 133 (see Figure 42) may be symmetrical. The width w26 of the land portion 133 at the location where the projection 155 exists may be, for example, 30 μm or more and 3000 μm or less. The first main surface 131a and the second main surface 131b of the wick sheet 130 may be formed flat over the frame portion 132 and each land portion 133. In Figure 37, the side wall of the frame portion 132 has substantially the same shape as the side wall of the land portion 133. However, this is not limited to this, and the side wall of the frame portion 132 does not necessarily have to have substantially the same shape as the side wall of the land portion 133.

[0246] The steam passage section 50 is an example of a through-space. The steam passage section 150 is primarily a passage through which the working steam 2a passes. The steam passage section 150 extends from the first main body surface 131a to the second main body surface 131b and penetrates the wick sheet 130.

[0247] As shown in Figures 40 and 41, the steam flow channel section 150 in this embodiment has a plurality of steam passages 151. Each steam passage 151 is formed inside the frame section 132 and outside the land section 133. That is, the steam passages 151 are formed between the frame section 132 and the land section 133, and between adjacent land sections 133. The planar shape of each steam passage 151 is an elongated rectangular shape. The steam flow channel section 150 is divided into a plurality of steam passages 151 by a plurality of land sections 133.

[0248] As shown in Figure 37, the steam passage 151 is formed to extend from the first main surface 131a to the second main surface 131b of the wick sheet 130. The steam passage 151 may also be formed by etching the first main surface 131a and the second main surface 131b of the wick sheet 130, respectively, in an etching process described later.

[0249] As shown in Figure 42, the steam passage 151 has a first curved wall surface 153a and a second curved wall surface 154a. The first wall surface 153a is located on the side of the first main body surface 131a and is curved in a shape that recesses inward in the width direction of the land portion 133. The second wall surface 154a is located on the side of the second main body surface 131b and is curved in a shape that recesses inward in the width direction of the land portion 133. The first wall surface 153a and the second wall surface 154a meet at a projection 155 that is formed to protrude inward from the steam passage 151. The projection 155 may be formed at an acute or obtuse angle in cross-section. The width w27 (see Figure 42) between a pair of projections 155 adjacent to each other across the steam passage 151 may be, for example, 30 μm or more and 3000 μm or less. Here, the width w27 between the pair of protrusions 155 refers to the distance measured in the width direction (Y direction) of the steam passage 151 at the location where the protrusions 155 exist.

[0250] The first wall surface 153a has a first wall surface end 153b located on the side of the first main body surface 131a. The upper end of the first wall surface 153a is a projection 155, which corresponds to the end of the first wall surface 153a on the side of the second main body surface 131b. The lower end of the first wall surface 153a is the first wall surface end 153b, which corresponds to the end of the first wall surface 153a on the side of the first main body surface 131a. The first wall surface 153a is in contact with the lower sheet 110 at the first wall surface end 153b. The first wall surface end 153b may be formed at an acute angle in cross-sectional view. Also, in Figure 42, the point of the first wall surface 153a that is most recessed inward in the width direction (Y direction) of the land portion 133 in cross-sectional view is indicated by reference numeral 153c.

[0251] The second wall surface 154a has a second wall surface end 154b located on the side of the second main body surface 131b. The upper end of the second wall surface 154a is the second wall surface end 154b, which corresponds to the end of the second wall surface 154a on the side of the second main body surface 131b. The lower end of the second wall surface 154a is a projection 155, which corresponds to the end of the second wall surface 154a on the side of the first main body surface 131a. The second wall surface 154a is in contact with the upper sheet 120 at the second wall surface end 154b. The second wall surface end 154b may also constitute the outer edge of the convex portion 164, which will be described later. The second wall surface end 154b may be formed at an obtuse angle in cross-sectional view.

[0252] In this embodiment, the first wall end 153b is located inside the steam flow path 150, beyond the projection 155, in a plan view. That is, in a plan view, the second wall end 154b, point 153c, projection 155, and first wall end 153b are located in the order of inside to outside in the width direction (Y direction) of the land portion 133. The outside corresponds to the side of the steam flow path 150. The planar area of ​​the steam passage 151 is maximum at the location of the second wall end 154b and minimum at the location of the first wall end 153b. The width w22 of the steam passage 151 (see Figure 42) may be, for example, 100 μm or more and 5000 μm or less. Here, the width w22 of the steam passage 151 is the width of the narrowest part of the steam passage 151, and in this case, it refers to the distance measured in the width direction (Y direction) at the location of the first wall end 153b. Furthermore, the width w22 of the steam passage 151 corresponds to the gap between adjacent land portions 133 in the width direction (Y direction).

[0253] As shown in Figure 42, let Lp be the distance between the second wall end 154b and the projection 155 in the width direction (Y direction) of the steam flow path section 150, and let Ls be the distance between the second wall end 154b and the first wall end 153b. In this case, the distance Ls may be 1.05 times or more and 2 times or less than or equal to 1.05 times or more and 1.8 times or less than or equal to 1.05 times the distance Lp. When the distance Ls is 1.05 times or more the distance Lp, the bonding area between the land section 133 and the lower sheet 110 increases, and the strength of the diffusion bonding near the first wall end 153b can be increased. When the distance Ls is 2 times or less the distance Lp, the width of the steam passage 151 is secured, and the working steam 2a can flow smoothly in the steam passage 151. The above distance Ls may be 6 μm or more and 500 μm or less. The above distance Lp may be 3 μm or more and 400 μm or less.

[0254] Furthermore, the distance Ls between the second wall end 154b and the first wall end 153b may be 1.1 to 10 times the width w25 of the protrusion 164, which will be described later. By setting the distance Ls to 1.1 times or more the width w25, the contact area between the land portion 133 and the lower sheet 110 is increased, and the strength of the connection by diffusion bonding or brazing near the first wall end 153b can be increased. By setting the distance Ls to 10 times or less the width w25, the width of the steam passage 151 is secured, and the operating steam 2a can flow smoothly in the steam passage 151.

[0255] The projection 155 in the thickness direction (Z direction) of the wick sheet 130 is located closer to the second body surface 131b than the intermediate position Pz between the first body surface 131a and the second body surface 131b. When the distance between the projection 155 and the second body surface 131b is t25, the distance t25 may be 5% or more, 10% or more, or 20% or more of the thickness t24 of the wick sheet 130, as described later. The distance t25 may also be 45% or less, 40% or less, or 30% or less of the thickness t24 of the wick sheet 130.

[0256] The steam flow path section 150, including the steam passage 151 configured in this way, constitutes a part of the sealed space 103 described above. As shown in Figure 37, the steam flow path section 150 according to this embodiment is mainly defined by the lower sheet 110, the upper sheet 120, and the frame portion 132 and land portion 133 of the wick sheet 130 described above. Each steam passage 151 has a relatively large flow path cross-sectional area to allow the working steam 2a to pass through.

[0257] Here, Figure 37 shows an enlarged view of the steam passages 151, etc., for clarity, and the number and arrangement of these steam passages 151, etc., differ from those in Figures 36, 40, and 41.

[0258] Incidentally, as shown in Figures 40 and 41, support portions 139 are provided within the steam flow path section 150 to support the land portions 133 on the frame portion 132. The support portions 139 support adjacent land portions 133 to each other. The support portions 139 are provided on both sides of the land portions 133 in the longitudinal direction (X direction). The support portions 139 may be formed so as not to obstruct the flow of working steam 2a diffusing through the steam flow path section 150. In this case, the support portions 139 are located on the side of the first main body surface 131a of the wick sheet 130, and a space communicating with the steam flow path section 150 is formed on the side of the second main body surface 131b. This makes the thickness of the support portions 139 thinner than the thickness of the wick sheet 130, preventing the steam passage 151 from being divided in the X and Y directions. However, the design is not limited to this, and the support portions 139 may also be located on the side of the second main body surface 131b. Furthermore, spaces communicating with the steam flow path 150 may be formed on both the side of the support portion 139 facing the first main body surface 131a and the side of the support portion 131b facing the second main body surface 131b.

[0259] As shown in Figures 40 and 41, alignment holes 135 may be provided at the four corners of the wick sheet 130.

[0260] Furthermore, as shown in Figure 36, the vapor chamber 100 may further include an injection section 104 at one end edge in the X direction for injecting the working fluid 2b into the sealed space 103. In the configuration shown in Figure 36, the injection section 104 is located on the side of the evaporation region SR. The injection section 104 has an injection channel 37 formed in the wick sheet 130. This injection channel 137 is formed on the side of the second main body surface 131b of the wick sheet 130 and is formed in a concave shape from the side of the second main body surface 131b. After the vapor chamber 100 is completed, the injection channel 137 is sealed. The injection channel 137 is also in communication with the vapor channel section 150, and the working fluid 2b is injected into the sealed space 103 by passing through the injection channel 137. Depending on the arrangement of the liquid channel section 160, the injection channel 137 may be made to communicate with the liquid channel section 160.

[0261] In this embodiment, the injection portion 104 is shown as being located on one of a pair of edges of the vapor chamber 100 in the X direction, but it is not limited to this and can be located at any position. The injection portion 104 may also be pre-formed to protrude from one of the edges of the vapor chamber 100 in the X direction.

[0262] As shown in Figures 37, 40, and 41, the liquid channel section 160 is provided on the second main body surface 131b of the wick sheet 130. The liquid channel section 160 is configured primarily for the working fluid 2b to pass through. This liquid channel section 160 constitutes a part of the sealed space 103 described above and is in communication with the vapor channel section 150. The liquid channel section 160 is configured as a capillary structure (wick) for transporting the working fluid 2b to the evaporation region SR. In this embodiment, the liquid channel section 160 is provided on the second main body surface 131b of each land section 133 of the wick sheet 130. The liquid channel section 160 may be formed over the entire second main body surface 131b of each land section 133.

[0263] As shown in Figure 43, the fluid flow channel section 160 is an example of a groove assembly containing multiple grooves. The fluid flow channel section 160 has multiple main channel grooves 161 through which the working fluid 2b passes and which are arranged in parallel with each other, and multiple connecting grooves 165 that communicate with the main channel grooves 161. The main channel grooves 161 of the fluid flow channel section 160 are an example of first grooves. The connecting grooves 165 of the fluid flow channel section 160 are an example of second grooves. In the example shown in Figure 43, each land section 133 contains six main channel grooves 161, but this is not limited to this. The number of main channel grooves 161 included in each land section 133 is arbitrary, and may be, for example, 3 to 20.

[0264] Each main channel groove 161 is formed to extend along the longitudinal direction (X direction) of the land portion 133, as shown in Figure 43. Multiple main channel grooves 161 are arranged parallel to each other. If the land portion 133 is curved in plan view, each main channel groove 161 may extend in a curved shape along the curvature direction of the land portion 133. In other words, each main channel groove 161 does not necessarily have to be formed in a straight line, nor does it have to extend parallel to the X direction.

[0265] The main channel groove 161 has a smaller channel cross-sectional area than the steam passage 151 of the steam channel section 150, primarily so that the working fluid 2b flows by capillary action. The main channel groove 161 is configured to transport the working fluid 2b condensed from the working steam 2a to the evaporation region SR. Each main channel groove 161 is spaced apart from each other in the width direction (Y direction).

[0266] The main channel groove 161 is formed by etching from the second main surface 131b of the wick sheet 130 in an etching process described later. As shown in Figure 42, the main channel groove 161 has a curved wall surface 162. This wall surface 162 defines the main channel groove 161 and is curved in a shape that bulges out toward the first main surface 131a. In the cross-section shown in Figure 42, the radius of curvature of each wall surface 162 may be smaller than the radius of curvature of the second wall surface 154a of the steam passage 151.

[0267] In Figure 43, the width w23 of the main groove 161 may be, for example, 2 μm or more and 500 μm or less. The width w23 of the main groove 161 is the length in the direction perpendicular to the longitudinal direction of the land portion 133, and in this case it is the dimension in the Y direction. The width w23 of the main groove 161 also represents the dimension on the second main body surface 131b.

[0268] Furthermore, as shown in Figure 42, the depth h21 of the main channel groove 161 may be, for example, 3 μm or more and 300 μm or less. Note that the depth h21 of the main channel groove 161 is the distance measured from the second main channel surface 131b in a direction perpendicular to the second main channel surface 131b, and in this case it is a dimension in the Z direction. Also, the depth h21 refers to the depth at the deepest point of the main channel groove 161.

[0269] As shown in Figure 43, each connecting groove 165 extends in a direction different from the X direction. In this embodiment, each connecting groove 165 is formed to extend in the Y direction and is formed perpendicular to the main channel groove 161. Some connecting grooves 165 are arranged to connect adjacent main channel grooves 161 to each other. Other connecting grooves 165 are arranged to connect the steam flow path section 150 (steam passage 151) to the main channel groove 161 closest to the steam flow path section 150. That is, the connecting groove 165 extends from the end of the land section 133 in the Y direction to the main channel groove 161 adjacent to that end. In this way, the steam passage 151 of the steam flow path section 150 and the main channel groove 161 are connected.

[0270] The connecting grooves 165 have a smaller flow path cross-sectional area than the steam passages 151 of the steam flow path section 150, primarily so that the working fluid 2b flows by capillary action. Each connecting groove 165 may be arranged at equal intervals in the longitudinal direction (X direction) of the land section 133.

[0271] The connecting groove 165, like the main channel groove 161, is formed by etching and has a curved wall surface (not shown) similar to that of the main channel groove 161. As shown in Figure 43, the width w24 (dimension in the X direction) of the connecting groove 165 may be 5 μm or more and 300 μm or less. The depth of the connecting groove 165 may be 3 μm or more and 300 μm or less.

[0272] The main channel groove 161 includes an intersection 166 that communicates with a connecting channel groove 165. At the intersection 166, the main channel groove 161 and the connecting channel groove 165 communicate in a T-shape. This prevents the connecting channel groove 165 on the other side (for example, the lower side in Figure 43) from communicating with the main channel groove 161 at the intersection 166 where one main channel groove 161 communicates with the connecting channel groove 165 on one side (for example, the upper side in Figure 43). As a result, at the intersection 166, the wall surface 162 of the main channel groove 161 is not cut out on both sides in the Y direction, and one wall surface 162 can be left intact. Therefore, even at the intersection 166, the working fluid 2b in the main channel groove 161 can be given a capillary action, and the reduction in the propulsive force of the working fluid 2b toward the evaporation region SR at the intersection 166 can be suppressed.

[0273] As shown in Figure 43, rows of liquid protrusions 163 are provided between adjacent main channel grooves 161 in the liquid flow channel section 160. In the example shown in Figure 43, each land section 133 contains seven rows of liquid protrusions 163, but this is not the only example. The number of liquid protrusions 163 included in each land section 133 is arbitrary; for example, it may be between 3 and 20 rows.

[0274] Each row of liquid protrusions 163 is formed to extend along the longitudinal direction (X direction) of the land portion 133, as shown in Figure 43. Multiple rows of liquid protrusions 163 are arranged parallel to each other. If the land portion 133 is curved in plan view, each row of liquid protrusions 163 may extend in a curved shape along the curvature direction of the land portion 133. In other words, each row of liquid protrusions 163 does not necessarily have to be formed in a straight line, nor does it have to extend parallel to the X direction. Each row of liquid protrusions 163 is arranged with space between them in the width direction (Y direction).

[0275] Each row of liquid protrusions 163 includes a plurality of protrusions 164 (liquid flow channel protrusions) arranged in the X direction. The protrusions 164 are provided within the liquid flow channel section 160 and protrude from the main channel groove 161 and connecting groove 165, contacting the upper sheet 120. In plan view, each protrusion 164 is formed in a rectangular shape with the X direction as its longitudinal direction. In the Y direction, a main channel groove 161 is positioned between adjacent protrusions 164. In the X direction, a connecting groove 165 is positioned between adjacent protrusions 164. The connecting groove 165 is formed to extend in the Y direction and connects adjacent main channel grooves 161 in the Y direction. This allows the working fluid 2b to flow between these main channel grooves 161.

[0276] The protrusions 164 are the parts of the wick sheet 130 that are not removed by etching in the etching process described later, and where the material remains. In this embodiment, as shown in Figure 43, the planar shape of the protrusions 164 is rectangular. The planar shape of the protrusions 164 corresponds to the shape of the wick sheet 130 at the position of the second main surface 131b. The width w25 of the protrusions 164 may be, for example, 5 μm or more and 500 μm or less. Note that the width w25 of the protrusions 164 refers to the value at the point where the width of the protrusions 164 is maximum.

[0277] The arrangement pitch of the protrusions 164 in the width direction (Y direction) may be, for example, 7 μm or more and 1000 μm or less. Here, the arrangement pitch of the protrusions 164 refers to the distance between the center of one protrusion 164 in the Y direction and the center of an adjacent protrusion 164 in the Y direction, and is measured in the Y direction.

[0278] In this embodiment, the protrusions 164 are arranged in a staggered (alternating) pattern. More specifically, the protrusions 164 of adjacent rows 163 in the Y direction are offset from each other in the X direction. This offset may be half the arrangement pitch of the protrusions 164 in the X direction. Note that the arrangement of the protrusions 164 is not limited to a staggered pattern, and they may be arranged in parallel. In this case, the protrusions 164 of adjacent rows 163 in the Y direction are aligned in the X direction as well.

[0279] The length L1 of each protrusion 164 may be uniform. Also, the length L1 of each protrusion 164 is longer than the width w24 of the connecting groove 165 (L1 > w24). Note that the length L1 of each protrusion 164 corresponds to the dimension of the protrusion 164 in the X direction and represents the maximum dimension in the X direction on the second main body surface 131b.

[0280] Incidentally, the materials constituting the lower sheet 110, upper sheet 120, and wick sheet 130 are not particularly limited as long as they have good thermal conductivity. The lower sheet 110, upper sheet 120, and wick sheet 130 may contain, for example, copper or a copper alloy. In this case, the thermal conductivity of each sheet 110, 120, and 130 can be increased, and the heat dissipation efficiency of the vapor chamber 100 can be increased. Also, when pure water is used as the working fluid 2a and 2b, corrosion can be prevented. Furthermore, if the desired heat dissipation efficiency can be obtained and corrosion can be prevented, these sheets 110, 120, and 130 can also be made of other metal materials such as aluminum or titanium, or other metal alloy materials such as stainless steel.

[0281] Furthermore, the thickness t21 of the vapor chamber 100 shown in Figure 37 may be, for example, 100 μm or more and 2000 μm or less. By making the thickness t21 of the vapor chamber 100 100 μm or more, the vapor flow path 150 can be properly secured, allowing the vapor chamber 100 to function properly. On the other hand, by making the thickness t21 2000 μm or less, it is possible to suppress the thickness t21 of the vapor chamber 100 from becoming too thick.

[0282] The thickness t22 of the lower sheet 110 may be, for example, 25 μm or more and 500 μm or less. By setting the thickness t22 of the lower sheet 110 to 25 μm or more, the mechanical strength of the lower sheet 110 can be ensured. On the other hand, by setting the thickness t22 of the lower sheet 110 to 500 μm or less, it is possible to suppress an increase in the thickness t21 of the vapor chamber 100. Similarly, the thickness t23 of the upper sheet 120 may be set in the same way as the thickness t22 of the lower sheet 110. The thickness t23 of the upper sheet 120 and the thickness t22 of the lower sheet 110 may be different.

[0283] The thickness t24 of the wick sheet 130 may be, for example, 50 μm or more and 1000 μm or less. By making the thickness t24 of the wick sheet 130 50 μm or more, the vapor flow path 150 can be properly secured, allowing the vapor chamber 100 to function properly. On the other hand, by making it 1000 μm or less, it is possible to suppress the thickness t21 of the vapor chamber 100 from becoming too thick.

[0284] Next, the manufacturing method of the vapor chamber 100 of this embodiment, which has the above configuration, will be explained with reference to Figures 44 to 46. Note that Figures 44 to 46 show the same cross-section as the cross-sectional view in Figure 37.

[0285] First, we will explain the manufacturing process of the wick sheet 130.

[0286] First, as shown in Figure 44, a flat metal material sheet M, including a lower surface Ma and an upper surface Mb, is prepared as a preparation step.

[0287] After the preparation step, as an etching step, as shown in Figure 45, the metal material sheet M is etched from the lower surface Ma and the upper surface Mb to form the vapor channel section 150 and the liquid channel section 160.

[0288] More specifically, a patterned resist film (not shown) is formed on the lower surface Ma and upper surface Mb of the metal material sheet M by photolithography. Subsequently, the lower surface Ma and upper surface Mb of the metal material sheet M are etched through the openings in the patterned resist film. As a result, the lower surface Ma and upper surface Mb of the metal material sheet M are etched in a patterned manner, forming a vapor channel section 150 and a liquid channel section 160 as shown in Figure 45. For the etching solution, for example, an iron chloride-based etching solution such as an aqueous solution of ferric chloride, or a copper chloride-based etching solution such as an aqueous solution of copper chloride can be used.

[0289] Etching may be performed simultaneously on the lower surface Ma and upper surface Mb of the metal material sheet M. However, it is not limited to this, and the etching of the lower surface Ma and upper surface Mb may be carried out as separate processes. Furthermore, the vapor flow channel 150 and the liquid flow channel 160 may be formed by etching simultaneously or in separate processes.

[0290] Furthermore, in the etching process, the lower surface Ma and upper surface Mb of the metal material sheet M are etched to obtain a predetermined outer contour shape as shown in Figures 40 and 41. That is, the edge of the wick sheet 130 is formed.

[0291] In this way, the wick sheet 130 according to this embodiment is obtained.

[0292] Following the manufacturing process of the wick sheet 130, the lower sheet 110, the upper sheet 120, and the wick sheet 130 are joined together in a joining process, as shown in Figure 46. The lower sheet 110 and the upper sheet 120 may be formed from rolled material having a desired thickness.

[0293] More specifically, the lower sheet 110, the wick sheet 130, and the upper sheet 120 are first stacked in this order. In this case, the first main surface 131a of the wick sheet 130 is superimposed on the second lower sheet surface 110b of the lower sheet 110, and the first upper sheet surface 120a of the upper sheet 120 is superimposed on the second main surface 131b of the wick sheet 130. At this time, the alignment holes 112 of the lower sheet 110, the alignment holes 135 of the wick sheet 130, and the alignment holes 122 of the upper sheet 120 are used to align each sheet 110, 120, and 130.

[0294] Next, the lower sheet 110, the wick sheet 130, and the upper sheet 120 are tack-fastened. For example, these sheets 110, 120, and 130 may be tack-fastened by spot resistance welding, or they may be tack-fastened by laser welding.

[0295] Next, the lower sheet 110, the wick sheet 130, and the upper sheet 120 are permanently joined by diffusion bonding. More specifically, the first main body surface 131a of the frame portion 132 and each land portion 133 of the wick sheet 130 is diffusion bonded to the second lower sheet surface 110b of the lower sheet 110. Also, the second main body surface 131b of the frame portion 132 and each land portion 133 of the wick sheet 130 is diffusion bonded to the first upper sheet surface 120a of the upper sheet 120. In this way, the sheets 110, 120, and 130 are diffusion bonded, and a sealed space 103 having a steam flow path portion 150 and a liquid flow path portion 160 is formed between the lower sheet 110 and the upper sheet 120.

[0296] After the joining process, the working fluid 2b is injected from the injection section 104 into the sealed space 103.

[0297] Subsequently, the injection channel 137 described above is sealed. For example, the injection section 104 may be partially melted to seal the injection channel 137. This blocks communication between the sealed space 103 and the outside, sealing the working fluid 2b into the sealed space 103 and preventing the working fluid 2b from leaking out of the sealed space 103.

[0298] As described above, the vapor chamber 100 according to this embodiment is obtained.

[0299] Next, the operation method of the vapor chamber 100, that is, the cooling method of the electronic device D, will be described.

[0300] The vapor chamber 100 obtained as described above is installed in the housing H of an electronic device E such as a mobile terminal, and an electronic device D such as a CPU, which is the device to be cooled, is attached to the second upper seat surface 120b of the upper seat 120. Alternatively, the vapor chamber 100 is attached to the electronic device D. The working fluid 2b in the sealed space 103 adheres to the walls of the sealed space 103 due to its surface tension, namely the first wall surface 153a and the second wall surface 154a of the vapor passage 151, the wall surface 162 of the main channel groove 161 of the liquid flow channel section 160, and the wall surface of the connecting groove 165. The working fluid 2b may also adhere to the portion of the second lower seat surface 110b of the lower seat 110 that is exposed to the vapor passage 151. Furthermore, the working fluid 2b may also adhere to the portion of the first upper seat surface 120a of the upper seat 120 that is exposed to the vapor passage 151, the main channel groove 161, and the connecting groove 165.

[0301] When the electronic device D generates heat in this state, the working fluid 2b present in the evaporation region SR (see Figures 40 and 41) receives heat from the electronic device D. The received heat is absorbed as latent heat, causing the working fluid 2b to evaporate (vaporize) and generate working steam 2a. Much of the generated working steam 2a diffuses within the steam passages 151 that constitute the sealed space 103 (see the solid arrows in Figure 40). The working steam 2a in each steam passage 151 leaves the evaporation region SR, and much of the working steam 2a is transported to the relatively lower temperature condensation region CR (the right-hand portion in Figures 40 and 41). In the condensation region CR, the working steam 2a is cooled mainly by radiating heat to the lower sheet 110. The heat received by the lower sheet 110 from the working steam 2a is transferred to the outside air via the housing member Ha (see Figure 37).

[0302] The working steam 2a condenses in the evaporation region SR by releasing heat to the lower sheet 110 in the condensation region CR, losing the latent heat absorbed in the evaporation region SR, and generating working fluid 2b. The generated working fluid 2b adheres to the first wall surfaces 153a and the second wall surfaces 154a of each steam passage 151, the second lower sheet surface 110b of the lower sheet 110, and the first upper sheet surface 120a of the upper sheet 120. Here, the working fluid 2b continues to evaporate in the evaporation region SR. Therefore, the working fluid 2b in the region of the liquid flow channel 160 other than the evaporation region SR (i.e., the condensation region CR) is transported toward the evaporation region SR by the capillary action of each main channel groove 161 (see dashed arrow in Figure 40). As a result, the working fluid 2b adhering to each steam passage 151, the second lower sheet surface 110b, and the first upper sheet surface 120a moves to the liquid flow channel 160, passes through the connecting groove 165, and enters the main channel groove 161. In this way, the working fluid 2b is filled into each main channel groove 161 and each connecting groove 165. As a result, the filled working fluid 2b gains a propulsive force toward the evaporation region SR due to the capillary action of each main channel groove 161 and is smoothly transported toward the evaporation region SR.

[0303] In the fluid flow channel section 160, each main channel groove 161 is connected to other adjacent main channel grooves 161 via a corresponding connecting groove 165. This allows the working fluid 2b to flow between adjacent main channel grooves 161, suppressing the occurrence of dryout in the main channel grooves 161. As a result, capillary action is imparted to the working fluid 2b in each main channel groove 161, and the working fluid 2b is smoothly transported toward the evaporation region SR.

[0304] The working fluid 2b, having reached the evaporation region SR, receives heat again from the electronic device D and evaporates. The working vapor 2a evaporated from the working fluid 2b moves through the connecting groove 165 in the evaporation region SR to the vapor passages 151, which have a larger flow path cross-sectional area, and diffuses within each vapor passage 151. In this way, the working fluids 2a and 2b recirculate within the sealed space 103 while repeatedly undergoing phase changes, i.e., evaporation and condensation, transporting and releasing heat from the electronic device D. As a result, the electronic device D is cooled.

[0305] Incidentally, in the evaporation region SR, the working steam 2a generated from the working fluid 2b moves from the liquid flow channel section 160 toward the steam passage 151. At this time, the working steam 2a flows out from the main channel groove 161, through the connecting grooves 165 adjacent to the convex portions 164 on the widthwise outer side of each liquid flow channel section 160, and into the steam passage 151.

[0306] Generally, the portion of the steam passage 151 facing the second main body surface 131b has a large pressure gradient of the working steam 2a in the thickness direction (Z direction), while the portion facing the first main body surface 131a has a small pressure gradient of the working steam 2a in the thickness direction (Z direction). In this embodiment, as shown in Figure 47, the projection 155 is located closer to the second main body surface 131b than to the intermediate position Pz between the first main body surface 131a and the second main body surface 131b. Therefore, when the vaporized working steam 2a spreads from the liquid flow path portion 160 into the steam passage 151, the pressure gradient in the vertical direction of the projection 155 becomes large near the projection 155. The pressure difference between the upper and lower portions of the projection 155 can become large. The upper portion of the projection 155 corresponds to the portion facing the second wall surface 154a, and the lower portion of the projection 155 corresponds to the portion facing the first wall surface 153a. Therefore, the air pressure of the working steam 2a in the upper part of the projection 155 can be made sufficiently greater than the air pressure of the working steam 2a in the lower part of the projection 155, allowing the working steam 2a to easily pass over the projection 155. This allows the working steam 2a to easily flow from the upper part of the projection 155 to the lower part. As a result, the projection 155 is less likely to be an obstacle to the passage of the working steam 2a, and the working steam 2a can diffuse smoothly from the projection 155 to the lower part of the projection 155.

[0307] Furthermore, in this embodiment, the first wall end 153b of the first wall surface 153a is located inside the steam flow path 150 in a plan view, relative to the projection 155. For this reason, the first wall surface 153a is formed to face inward towards the steam passage 151. As a result, the working steam 2a that has wrapped around from the upper part to the lower part of the projection 155 is guided along the first wall surface 153a to the inside of the steam passage 151 in the width direction (Y direction). As a result, the diffusion of the working steam 2a inside the steam passage 151 is smooth, and the cooling capacity of the vapor chamber 100 can be increased. The radius of curvature of the first wall surface 153a may gradually increase toward the first wall end 153b. As a result, as the radius of curvature increases, the obstacle to the flow of working steam 2a toward the first main body surface 131a increases. This allows for even smoother diffusion of the working steam 2a inside the steam passage 151.

[0308] Meanwhile, in the condensation region CR, the working fluid 2b generated from the working steam 2a moves from the steam passage 151 toward the liquid flow channel section 160. At this time, the working fluid 2b passes through the connecting grooves 165 adjacent to the convex portions 164 on the widthwise outer side of each liquid flow channel section 160 and enters the main channel groove 161.

[0309] In this embodiment, the first wall end portion 153b of the first wall surface 153a is located inside the steam flow path 150 in a plan view, relative to the projection 155. Therefore, the working fluid 2b that has flowed through the steam passage 151 is guided along the first wall surface 153a to the liquid flow path 160. As a result, the working fluid 2b flows smoothly into the liquid flow path 160. Furthermore, since the working fluid 2b can easily overcome the projection 155, the projection 155 is less likely to obstruct the passage of the working fluid 2b, and the flow of the working fluid 2b from the projection 155 to the liquid flow path 160 can be made smooth.

[0310] Furthermore, in this embodiment, the projection 155 is located closer to the second main body surface 131b than to the intermediate position Pz. As a result, the radius of curvature of the second wall surface 154a can be made smaller than that of the first wall surface 153a. This enhances the capillary action of the second wall surface 154a, allowing the working fluid 2b to flow smoothly into the fluid flow channel 160. In addition, the enhanced capillary action also improves the retention effect of the working fluid 2b by the second wall surface 154a. As a result, the amount of working fluid 2b transported to the evaporation region SR can be increased.

[0311] Furthermore, in this embodiment, the first wall end portion 153b of the first wall surface 153a is located inside the steam flow path portion 150 in a plan view, rather than the projection portion 155, making it easier to check for shape defects at the widthwise end portion of the land portion 133 in a plan view.

[0312] Furthermore, in this embodiment, since the first wall surface 153a is curved toward the liquid flow channel section 160, the volume of the vapor passage 151 is increased, and the cooling capacity of the vapor chamber 100 can be improved.

[0313] The present invention is not limited to the embodiments and modifications described above, and the components can be modified and implemented in practice without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriate combinations of the multiple components disclosed in the embodiments and modifications described above. Some components may be deleted from all the components shown in each embodiment and modification.

Claims

[Claim 1] A main body sheet for a vapor chamber in which a working fluid is sealed, The first main surface and A second main body surface is provided on the opposite side from the first main body surface, A through space extending from the first main body surface to the second main body surface, A plurality of first grooves provided on the first main body surface and communicating with the through space, comprising a plurality of first grooves extending in a first direction, The aforementioned through space extends in a first direction in a plan view, A body sheet for a vapor chamber, wherein, when viewed in a cross section perpendicular to the first direction, the through space has a first opening located on the first body surface and a second opening located on the second body surface, the second opening extending from a region overlapping the first opening in a plan view to a position overlapping the first groove in a plan view.

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