Vapor chamber and electronic device

Abstract

To provide a wick sheet for a vapor chamber that can be easily manufactured.SOLUTION: A wick sheet for a vapor chamber 1 according to the present invention comprises a first surface, and a second surface provided on the side opposite to the first surface. The first surface is provided with a liquid flow passage part constituting a portion of a sealed space, and through which working liquid in a liquid state is passed. The second surface is provided with a vapor flow passage part communicating with the liquid flow passage part, constituting a portion of the sealed space, and through which vapor of the working liquid is passed.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a wick sheet for a vapor chamber having a sealed space in which a hydraulic fluid is sealed, a vapor chamber, and a method for manufacturing a vapor chamber. [Background technology]

[0002] Devices that generate heat, such as central processing units (CPUs), light-emitting diodes (LEDs), and power semiconductors used in mobile devices such as mobile terminals and tablet terminals, are cooled by heat dissipation members such as heat pipes (see, for example, Patent Document 1). In recent years, in order to make mobile terminals thinner, there has been a demand for thinner heat dissipation members, and vapor chambers that can be made thinner than heat pipes have been developed. A working fluid is sealed inside the vapor chamber, and this working fluid absorbs the heat of the device and releases it to the outside, thereby cooling the device.

[0003] More specifically, the working fluid in the vapor chamber receives heat from the device in a portion (evaporation portion) close to the device and evaporates into vapor, and the vapor then moves to a position away from the evaporation portion, where it is cooled and condenses into liquid. A liquid flow path portion having a capillary structure (wick) is provided in the vapor chamber, and the liquefied working fluid passes through this liquid flow path portion and is transported to the evaporation portion, where it receives heat again and evaporates. In this way, the working fluid circulates through the vapor chamber while repeatedly changing phases, i.e., evaporating and condensing, thereby transferring heat from the device and increasing the heat transport efficiency.

[0004] A known vapor chamber includes a first metal sheet and a second metal sheet joined to the first metal sheet. A vapor flow path through which vapor of the working fluid passes is provided on the surface of the first metal sheet facing the second metal sheet, and a liquid flow path through which liquid working fluid passes is provided on the surface of the second metal sheet facing the first metal sheet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-59693 A Summary of the Invention [Problem to be solved by the invention]

[0006] In this way, when each metal sheet is provided with a vapor flow path portion or a liquid flow path portion, each metal sheet is processed to provide such a flow path portion. This causes a problem that the manufacturing process of the vapor chamber becomes complicated. In addition, when joining two metal sheets, a high degree of alignment is required between the flow path portion provided on one metal sheet and the flow path portion provided on the other metal sheet. This causes a problem that it is difficult to simplify the manufacturing of the vapor chamber.

[0007] The present invention has been made in consideration of these points, and aims to provide a wick sheet for a vapor chamber that can be easily manufactured, a vapor chamber, and a method for manufacturing a vapor chamber. [Means for solving the problem]

[0008] The present invention relates to A wick sheet for a vapor chamber, which is interposed between a first sheet and a second sheet and has a sealed space in which a working liquid is sealed, a first surface that contacts the first sheet; a second surface provided on the opposite side to the first surface and in contact with the second sheet; a liquid flow path portion provided on the first surface, constituting a part of the sealed space, through which the liquid working fluid passes; a wick sheet for a vapor chamber, the wick sheet including a vapor flow path portion provided on the second surface, communicating with the liquid flow path portion to form a part of the sealed space, and through which vapor of the working liquid passes; to provide.

[0009] In the above-mentioned wick sheet for the vapor chamber, The vapor flow path portion is formed in a concave shape on the second surface of the wick sheet, The liquid passage portion further includes a communication portion that communicates with the vapor passage portion. This may be done.

[0010] In addition, in the above-mentioned wick sheet for the vapor chamber, The liquid flow path portion has a plurality of main grooves through which the liquid working fluid passes, The communication portion is in contact with and communicates with a plurality of the main grooves. This may be done.

[0011] In addition, in the above-mentioned wick sheet for the vapor chamber, The communication portion is formed in a concave shape on the first surface of the wick sheet, A wall surface defining the steam flow path portion and a wall surface defining the communication portion are communicated with each other via a through-portion and are curved toward the through-portion. This may be done.

[0012] In addition, in the above-mentioned wick sheet for the vapor chamber, A plurality of flow path protrusions are provided in the steam flow path portion and protrude from a bottom of the steam flow path portion and abut against the second sheet, In a cross section including the centers of a pair of flow path protrusions adjacent to the through-hole on both sides of the through-hole, the width of the through-hole is smaller than a gap between the pair of flow path protrusions and / or a width of the corresponding communication portion. This may be done.

[0013] In addition, in the above-mentioned wick sheet for the vapor chamber, A plurality of flow path protrusions are provided in the steam flow path portion, the flow path protruding from a bottom of the steam flow path portion and contacting the second sheet. This may be done.

[0014] In addition, in the above-mentioned wick sheet for the vapor chamber, The plurality of flow path protrusions are arranged in a staggered manner in a plan view. This may be done.

[0015] In addition, in the above-mentioned wick sheet for the vapor chamber, The communication portion is disposed between the flow path protruding portions adjacent to each other in a plan view. This may be done.

[0016] In addition, in the above-mentioned wick sheet for the vapor chamber, The steam flow path portion extends from the second surface to the first surface. This may be done.

[0017] In addition, in the above-mentioned wick sheet for the vapor chamber, The liquid flow path portion is also provided on the second surface. This may be done.

[0018] In addition, in the above-mentioned wick sheet for the vapor chamber, The liquid flow path portion extends in a first direction and has a plurality of main grooves through which the liquid working fluid passes, and a communication groove that connects adjacent main grooves to each other, The steam flow path portion is in contact with and communicates with the communication groove. This may be done.

[0019] In addition, in the above-mentioned wick sheet for the vapor chamber, The liquid flow path portion extends in a first direction and has a plurality of main grooves through which the liquid working fluid passes, and a communication groove that connects adjacent main grooves to each other, the main groove provided in the first surface and the main groove provided in the second surface overlap each other in a plan view. This may be done.

[0020] In addition, in the above-mentioned wick sheet for the vapor chamber, The liquid flow path portion extends in a first direction and has a plurality of main grooves through which the liquid working fluid passes, and a communication groove that connects adjacent main grooves to each other, the main groove provided in the first surface and the main groove provided in the second surface do not at least partially overlap each other in a plan view; This may be done.

[0021] In addition, in the above-mentioned wick sheet for the vapor chamber, The steam flow path portion is in contact with and communicates with the communication groove. This may be done.

[0022] In addition, in the above-mentioned wick sheet for the vapor chamber, A frame portion defining the steam flow path portion on the inside in a plan view; A land portion provided in the steam flow path portion, This may be done.

[0023] In addition, in the above-mentioned wick sheet for the vapor chamber, the land portion has a first land surface constituting the first surface and a second land surface constituting the second surface, the liquid flow path portion includes a first land liquid flow path portion provided on the first land surface; This may be done.

[0024] In addition, in the above-mentioned wick sheet for the vapor chamber, The liquid flow path portion further includes a second land liquid flow path portion provided on the second land surface. This may be done.

[0025] In addition, in the above-mentioned wick sheet for the vapor chamber, The liquid flow path portion extends in a first direction and has a plurality of main grooves through which the liquid working fluid passes, and a communication groove that connects adjacent main grooves to each other, The steam flow path portion is in contact with and communicates with the communication groove. This may be done.

[0026] In addition, in the above-mentioned wick sheet for the vapor chamber, The liquid flow path portion extends in a first direction and has a plurality of main grooves through which the liquid working fluid passes, and a communication groove that connects adjacent main grooves to each other, the main groove provided in the first land surface and the main groove provided in the second land surface overlap each other in a plan view; This may be done.

[0027] In addition, in the above-mentioned wick sheet for the vapor chamber, The liquid flow path portion extends in a first direction and has a plurality of main grooves through which the liquid working fluid passes, and a communication groove that connects adjacent main grooves to each other, the main groove provided in the first land surface and the main groove provided in the second land surface do not at least partially overlap each other in a plan view; This may be done.

[0028] In addition, in the above-mentioned wick sheet for the vapor chamber, The steam flow path portion is in contact with and communicates with the communication groove. This may be done.

[0029] In addition, in the above-mentioned wick sheet for the vapor chamber, a first support portion that supports the land portion on the frame portion is provided in the steam flow path portion; This may be done.

[0030] In addition, in the above-mentioned wick sheet for the vapor chamber, A plurality of the land portions are provided within the steam flow path portion, A second support portion is provided in the steam flow path portion to support the adjacent land portions. This may be done.

[0031] In addition, in the above-mentioned wick sheet for the vapor chamber, The frame portion has a first frame surface constituting the first surface and a second frame surface constituting the second surface, The liquid flow path portion includes a first frame body fluid flow path portion provided on the first frame body surface. This may be done.

[0032] In addition, in the above-mentioned wick sheet for the vapor chamber, The liquid flow path portion further includes a second frame body fluid flow path portion provided on the second surface. This may be done.

[0033] In addition, in the above-mentioned wick sheet for the vapor chamber, the liquid flow path portion has a plurality of main grooves each extending in a first direction and through which the liquid working fluid passes, a convex portion row including a plurality of convex portions arranged in the first direction via a communication groove is provided between a pair of adjacent main grooves, the main groove includes an intersection portion communicating with the communication groove, and a main groove body portion located at a position different from the intersection portion in the first direction and located between a pair of the protruding portions adjacent to each other. This may be done.

[0034] In addition, in the above-mentioned wick sheet for the vapor chamber, a depth of the intersection portion of the main groove is greater than a depth of a main groove body portion; This may be done.

[0035] In addition, in the above-mentioned wick sheet for the vapor chamber, A depth of the intersection of the main grooves is greater than a depth of the connecting grooves. This may be done.

[0036] In addition, in the above-mentioned wick sheet for the vapor chamber, The communication grooves communicate with a corresponding pair of the main grooves, The width of the connecting groove is greater than the width of the main groove. This may be done.

[0037] In addition, in the above-mentioned wick sheet for the vapor chamber, The depth of the connecting groove is greater than the depth of the main groove. This may be done.

[0038] In addition, in the above-mentioned wick sheet for the vapor chamber, The protrusions are arranged in a staggered pattern. This may be done.

[0039] The present invention also provides a method for producing a semiconductor device comprising the steps of: A vapor chamber having a sealed space in which a hydraulic fluid is sealed, The first sheet, A second sheet; a vapor chamber including the above-mentioned wick sheet interposed between the first sheet and the second sheet; to provide.

[0040] In addition, in the vapor chamber described above, The first sheet has a first peripheral portion provided on the outer side of the wick sheet in a plan view, The second sheet has a second peripheral portion provided on the outer side of the wick sheet in a plan view, A spacer member is interposed between the first peripheral portion and the second peripheral portion, The first peripheral portion and the second peripheral portion may be diffusion bonded via the spacer member.

[0041] In addition, in the vapor chamber described above, The first sheet has a first thermal fusion layer provided on the outer side of the wick sheet in a plan view on the surface of the wick sheet side, The second sheet has a second thermal fusion layer provided on the outer side of the wick sheet in a plan view on the surface of the wick sheet side, The first heat-sealing layer and the second heat-sealing layer are heat-sealed. This may be done.

[0042] In addition, in the vapor chamber described above, The surface of the first sheet on the side of the wick sheet is formed flat. This may be done.

[0043] In addition, in the vapor chamber described above, The first sheet and the wick sheet are diffusion bonded, and the second sheet and the wick sheet are diffusion bonded. This may be done.

[0044] In addition, in the vapor chamber described above, The first sheet has a first main body sheet provided on the wick sheet side and a first reinforcing sheet provided on the opposite side of the first main body sheet to the wick sheet side, The first reinforcing sheet has a higher mechanical strength than the first main body sheet. This may be done.

[0045] In addition, in the vapor chamber described above, The second sheet has a second main body sheet provided on the wick sheet side and a second reinforcing sheet provided on the opposite side of the second main body sheet to the wick sheet side, The second reinforcing sheet has a higher mechanical strength than the second main body sheet. This may be done.

[0046] The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: A method for manufacturing a vapor chamber having a sealed space filled with a working fluid, comprising the steps of: a wick sheet fabrication process for fabricating a wick sheet having a first surface and a second surface provided on the opposite side to the first surface, the wick sheet having a liquid flow path provided on the first surface, constituting a part of the sealed space and through which the liquid working fluid passes, and a vapor flow path provided on the second surface, communicating with the liquid flow path and constituting a part of the sealed space, and through which vapor of the working fluid passes; a joining step of joining the first sheet and the second sheet with the wick sheet interposed between the first sheet and the second sheet, forming the sealed space between the first sheet and the second sheet; and a sealing step of sealing the working fluid in the sealed space. to provide.

[0047] In addition, in the above-mentioned method for manufacturing a vapor chamber, The first sheet has a first peripheral portion provided on the outer side of the wick sheet in a plan view, The second sheet has a second peripheral portion provided on the outer side of the wick sheet in a plan view, In the bonding step, a spacer member is interposed between the first peripheral portion of the first sheet and the second peripheral portion of the second sheet, and the first peripheral portion and the second peripheral portion are diffusion bonded via the spacer member. This may be done.

[0048] In addition, in the above-mentioned method for manufacturing a vapor chamber, The first sheet has a first thermal fusion layer provided on the outer side of the wick sheet in a plan view on the surface of the wick sheet side, The second sheet has a second thermal fusion layer provided on the outer side of the wick sheet in a plan view on the surface of the wick sheet side, In the joining step, the first heat-sealing layer and the second heat-sealing layer are heat-sealed. This may be done.

[0049] In addition, in the above-mentioned method for manufacturing a vapor chamber, In the bonding step, the first sheet and the wick sheet are diffusion bonded, and the second sheet and the wick sheet are diffusion bonded. This may be done.

[0050] In addition, in the above-mentioned method for manufacturing a vapor chamber, The first sheet has a first main body sheet provided on the wick sheet side, and a first reinforcing sheet provided on the opposite side of the first main body sheet to the wick sheet side, The first reinforcing sheet has a higher mechanical strength than the first main body sheet. This may be done.

[0051] In addition, in the above-mentioned method for manufacturing a vapor chamber, The second sheet has a second main body sheet provided on the wick sheet side and a second reinforcing sheet provided on the opposite side of the second main body sheet to the wick sheet side, The second reinforcing sheet has a higher mechanical strength than the second main body sheet. This may be done. Effect of the Invention

[0052] According to the present invention, the manufacturing process is simple. [Brief description of the drawings]

[0053] [Figure 1] FIG. 1 is a schematic perspective view illustrating an electronic device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a top view showing the vapor chamber according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is a cross-sectional view of the vapor chamber shown in FIG. 2 taken along line AA. [Figure 4] FIG. 4 is a top view of the wick sheet of FIG. [Diagram 5]FIG. 5 is a bottom view of the wick sheet of FIG. [Figure 6] FIG. 6 is a partially enlarged bottom view showing the lower liquid flow path portion of FIG. [Figure 7] FIG. 7 is an enlarged cross-sectional view taken along line BB in FIG. 5, showing the main groove together with the lower metal sheet. [Figure 8] FIG. 8 is a view for explaining a wick sheet preparing step in the method for manufacturing a vapor chamber according to the first embodiment of the present invention. [Figure 9] FIG. 9 is a diagram for explaining a resist forming step in the method for manufacturing a vapor chamber according to the first embodiment of the present invention. [Figure 10] FIG. 10 is a diagram for explaining a resist patterning step in the method for manufacturing a vapor chamber according to the first embodiment of the present invention. [Figure 11] FIG. 11 is a view for explaining an etching step in the method for manufacturing a vapor chamber according to the first embodiment of the present invention. [Figure 12] FIG. 12 is a view for explaining a resist removing step in the method for manufacturing a vapor chamber according to the first embodiment of the present invention. [Figure 13] FIG. 13 is a view for explaining an assembly process in the manufacturing method of the vapor chamber according to the first embodiment of the present invention. [Figure 14] FIG. 14 is a view for explaining a temporary fixing step in the manufacturing method of the vapor chamber according to the first embodiment of the present invention. [Figure 15] FIG. 15 is a view for explaining a bonding step in the manufacturing method for the vapor chamber according to the first embodiment of the present invention. [Figure 16] FIG. 16 is a diagram for explaining a vacuum drawing step in the manufacturing method for a vapor chamber according to the first embodiment of the present invention. [Figure 17] FIG. 17 is a view for explaining a step of injecting a working liquid in the manufacturing method of the vapor chamber according to the first embodiment of the present invention. [Figure 18]FIG. 18 is a view for explaining a sealing step in the manufacturing method for the vapor chamber according to the first embodiment of the present invention. [Figure 19] FIG. 19 is a partially enlarged bottom view showing a modified example (first modified example) of the lower liquid flow path section in FIG. [Figure 20] FIG. 20 is an enlarged cross-sectional view taken along line CC in FIG. 19, showing the connecting groove together with the lower metal sheet. [Figure 21] FIG. 21 is an enlarged cross-sectional view taken along line DD in FIG. 19, showing the main groove and the connecting groove together with the lower metal sheet. [Figure 22] FIG. 22 is a partially enlarged bottom view showing a modified example (second modified example) of the liquid flow path portion of FIG. [Figure 23] FIG. 23 is a cross-sectional view showing a vapor chamber according to a second embodiment of the present invention, and corresponds to FIG. [Figure 24] FIG. 24 is a cross-sectional view showing a modified example of the vapor chamber shown in FIG. [Diagram 25] FIG. 25 is a top view showing a vapor chamber according to the third embodiment of the present invention. [Figure 26] FIG. 26 is a cross-sectional view of the vapor chamber shown in FIG. 25 taken along line BB. [Figure 27] FIG. 27 is a top view of the wick sheet of FIG. [Figure 28] FIG. 28 is a bottom view of the wick sheet of FIG. [Figure 29] FIG. 29 is a cross-sectional view taken along line EE in FIG. [Diagram 30] FIG. 30 is a partially enlarged bottom view showing the lower liquid flow path portion of FIG. [Diagram 31] FIG. 31 is a cross-sectional view showing a modified example of the vapor chamber shown in FIG. [Diagram 32] FIG. 32 is a partially enlarged cross-sectional view showing the lower liquid flow path section and the upper liquid flow path section of FIG. [Diagram 33] FIG. 33 is a partially enlarged cross-sectional view showing a modification of the lower liquid flow path section and the upper liquid flow path section shown in FIG. [Diagram 34]FIG. 34 is a cross-sectional view showing a vapor chamber according to the fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to this specification, the scale and the aspect ratio are appropriately changed and exaggerated from those of the actual objects for the convenience of illustration and understanding.

[0055] 1 to 22, a wick sheet for a vapor chamber, a vapor chamber, and a method for manufacturing a vapor chamber according to an embodiment of the present invention will be described. The vapor chamber 1 according to the present embodiment is a device mounted on an electronic device E in order to cool a device D as a heat generating body housed in the electronic device E. Examples of the device D include electronic devices (cooled devices) that generate heat, such as central processing units (CPUs), light-emitting diodes (LEDs), and power semiconductors used in mobile devices such as portable terminals and tablet terminals.

[0056] Here, first, an electronic device E equipped with the vapor chamber 1 according to the present embodiment will be described by taking a tablet terminal as an example. As shown in FIG. 1, the electronic device E (tablet terminal) includes a housing H, a device D accommodated in the housing H, and a vapor chamber 1. In the electronic device E shown in FIG. 1, a touch panel display TD is provided on the front surface of the housing H. The vapor chamber 1 is accommodated in the housing H and arranged so as to be in thermal contact with the device D. This allows the vapor chamber 1 to receive heat generated in the device D when the electronic device E is used. The heat received by the vapor chamber 1 is released to the outside of the vapor chamber 1 via the working liquid 2 described later. In this way, the device D is effectively cooled. When the electronic device E is a tablet terminal, the device D corresponds to a central processing unit or the like.

[0057] Next, the vapor chamber 1 according to this embodiment will be described. The vapor chamber 1 has a sealed space 3 in which a working liquid 2 is sealed, and the working liquid 2 in the sealed space 3 undergoes repeated phase changes to effectively cool the device D of the electronic device E described above. The vapor chamber 1 is generally formed in a thin, flat plate shape. The planar shape of the vapor chamber 1 is arbitrary, and may be a rectangular shape as shown in FIG. 2.

[0058] (First embodiment) As shown in FIG. 2 and FIG. 3, the vapor chamber 1 includes a lower metal sheet 10 (first sheet), an upper metal sheet 20 (second sheet), and a wick sheet 30 (hereinafter, simply referred to as the wick sheet 30) for the vapor chamber 1 interposed between the lower metal sheet 10 and the upper metal sheet 20. In the embodiment shown in FIG. 2, in order to simplify the explanation, an example is shown in which the lower metal sheet 10, the upper metal sheet 20, and the wick sheet 30 are all formed in a rectangular shape in a plan view, but this is not limited to this. Here, the plan view refers to a state in which the vapor chamber 1 is viewed from a direction perpendicular to the surface that receives heat from the device D (the lower surface 10a of the lower metal sheet 10) and the surface that releases the received heat (the upper surface 20b of the upper metal sheet 20), and corresponds to, for example, a state in which the vapor chamber 1 is viewed from above (the state shown in FIG. 2) or a state in which it is viewed from below.

[0059] 3, a sealed space 3 filled with a working fluid 2 is formed between the lower metal sheet 10 and the upper metal sheet 20. More specifically, the sealed space 3 is formed by an upper steam flow path recess 32, a communication recess 35, and a main flow path groove 41 and a communication groove 45 of a lower liquid flow path section 40, which are provided in the wick sheet 30 and will be described later. Examples of the working fluid 2 include pure water, ethanol, methanol, and acetone.

[0060] The lower metal sheet 10 has a lower surface 10a and an upper surface 10b (the surface on the wick sheet 30 side) provided on the opposite side to the lower surface 10a. Of these, the upper surface 10b abuts against a lower surface 30a (described later) of the wick sheet 30. In this embodiment, the lower surface 10a and the upper surface 10b are formed in a flat shape. That is, the lower metal sheet 10 is formed as a flat rectangular sheet as a whole.

[0061] 2 and 3, the lower metal sheet 10 has a heat receiving section 11 that receives heat from the device D. The device D is attached to the lower surface 10a of the lower metal sheet 10 (particularly, the lower surface of the heat receiving section 11). The heat receiving section 11, i.e., the portion where the device D is attached, can be disposed at any position on the lower metal sheet 10, but FIG. 2 shows an example in which it is disposed at the center of the lower metal sheet 10. In this case, it is possible to suppress the attitude of the mobile terminal in which the vapor chamber 1 is installed from affecting the stabilization of the operation of the vapor chamber 1.

[0062] The lower metal sheet 10 further has a lower peripheral edge portion 12 (first peripheral edge portion) provided on the outer side of the wick sheet 30 in a plan view. A spacer member 50 described below abuts against this lower peripheral edge portion 12 and is diffusion bonded to the spacer member 50. The lower peripheral edge portion 12 is formed around the entire periphery of the wick sheet 30 in a plan view, and is formed in a rectangular frame shape.

[0063] As shown in Figs. 2 and 3, the upper metal sheet 20 has a lower surface 20a (the surface on the wick sheet 30 side) and an upper surface 20b provided on the opposite side to the lower surface 20a. Of these, the lower surface 20a abuts against an upper surface 30b (described later) of the wick sheet 30. A housing member Ha constituting a part of a housing of a mobile terminal or the like abuts against the upper surface 20b. As a result, heat received from the device D is cooled by the outside air via the upper metal sheet 20 and the housing member Ha. In this embodiment, the lower surface 20a and the upper surface 20b are formed in a flat shape. That is, the upper metal sheet 20 is formed as a flat rectangular sheet as a whole.

[0064] The upper metal sheet 20 further has an upper peripheral edge portion 21 (second peripheral edge portion) provided on the outer side of the wick sheet 30 in a plan view. A spacer member 50 described below abuts against this upper peripheral edge portion 21 and is diffusion bonded to the spacer member 50. The upper peripheral edge portion 21 is formed around the entire periphery of the wick sheet 30 in a plan view, and is formed in a rectangular frame shape.

[0065] As shown in FIG. 3, the upper metal sheet 20 further has an injection hole 22 for injecting the working liquid 2 into the sealed space 3. The injection hole 22 extends perpendicularly to the upper surface 20b and the lower surface 20a from the upper surface 20b to the lower surface 20a. The injection hole 22 is disposed at a position overlapping an upper steam flow path recess 32 of the wick sheet 30, which will be described later, in a plan view, and communicates with the upper steam flow path recess 32. The position of the injection hole 22 is arbitrary as long as the working liquid 2 can be injected into the sealed space 3. The injection hole 22 may be provided in the lower metal sheet 10 instead of the upper metal sheet 20. The injection hole 22 may be provided so as to extend from the spacer member 50 to the wick sheet 30 so as to inject the working liquid 2 into the sealed space 3.

[0066] A sealing member 23 is provided in injection hole 22, which seals injection hole 22 after hydraulic fluid 2 is injected. This sealing member 23 is preferably formed from the same material as upper metal sheet 20.

[0067] Incidentally, when the vapor chamber 1 is installed inside a mobile terminal, the vertical relationship between the lower metal sheet 10 and the upper metal sheet 20 may be lost depending on the posture of the mobile terminal. However, in this embodiment, for convenience, the metal sheet that receives heat from the device D is referred to as the lower metal sheet 10, and the metal sheet that dissipates the received heat is referred to as the upper metal sheet 20, and the description will be given assuming that the lower metal sheet 10 is disposed on the lower side and the upper metal sheet 20 is disposed on the upper side.

[0068] As shown in Fig. 3, the wick sheet 30 has a lower surface 30a (first surface), an upper surface 30b (second surface) provided on the opposite side to the lower surface 30a, and an outer surface 30c. The lower surface 30a abuts against the upper surface 10b of the lower metal sheet 10, and the upper surface 30b abuts against the lower surface 20a of the upper metal sheet 20. The outer surface 30c is formed so as to extend from the lower surface 30a to the upper surface 30b, and is a surface that a spacer member 50 described later abuts against from the outside. Here, in Fig. 3, in order to clarify the drawing, the upper steam flow path recess 32, the upper flow path protrusion 34, and the lower liquid flow path section 40 described later are shown enlarged, and the number and arrangement of the main grooves 41 of the upper steam flow path recess 32, the upper flow path protrusion 34, and the lower liquid flow path section 40 are different from those in Figs. 2, 4, and 5.

[0069] As shown in FIG. 4, the wick sheet 30 further has an evaporation section 31 where the working liquid 2 evaporates to generate steam, and an upper steam flow path recess 32 (steam flow path section) provided on the upper surface 30b. The steam flow path section in this embodiment is constituted by this upper steam flow path recess 32. Among them, the evaporation section 31 is a section to which heat received from the device D by the heat receiving section 11 (see FIG. 2 and FIG. 3) of the lower metal sheet 10 is transferred, and the working liquid 2 is evaporated by this heat. That is, the heat from the heat receiving section 11 can be transferred not only to the area overlapping with the wick sheet 30 in a plan view, but also to the periphery of the area. Therefore, the evaporation section 31 can correspond to a region including the part overlapping with the heat receiving section 11 and the surrounding area in a plan view.

[0070] The upper steam flow passage recess 32 constitutes a part of the sealed space 3, and is mainly configured so that the steam of the working fluid 2 generated in the evaporator 31 passes through it. The upper steam flow passage recess 32 is formed in a concave shape on the upper surface 30b of the wick sheet 30 by etching the upper surface 30b in an etching process described later. As a result, the upper steam flow passage recess 32 has a wall surface 33 formed in a curved shape as shown in FIG. 3. The wall surface 33 defines the upper steam flow passage recess 32 and is curved in a shape that bulges toward the lower surface 30a. As shown in FIG. 4, the upper steam flow passage recess 32 is formed so as to be concave from the upper surface 30b toward the lower surface 30a over the entire upper surface 30b of the wick sheet 30, and the wall surface 33 is formed to have a plurality of curved concave portions. The side wall of the upper steam flow passage recess 32 is formed by a spacer member 50 described later.

[0071] In plan view, the heat receiving portion 11 of the lower metal sheet 10 is disposed in the center of the upper steam flow passage recess 32. As a result, the steam in the upper steam flow passage recess 32 diffuses in a direction away from the center overlapping with the heat receiving portion 11, and most of the steam is transported to the peripheral portion of the wick sheet 30, which has a relatively low temperature.

[0072] 3 and 4, a plurality of upper flow passage protrusions 34 (flow passage protrusions) are provided in the upper steam flow passage recess 32, protruding upward from the bottom of the wall surface 33 of the upper steam flow passage recess 32. The upper flow passage protrusions 34 are portions that are not etched in the etching step described below, and the material of the wick sheet 30 remains.

[0073] 3, the upper flow path protrusion 34 has an upper surface 34a (protruding end surface) located on the same plane as the upper surface 30b of the wick sheet 30. This upper surface 34a abuts against the lower surface 20a of the upper metal sheet 20. This improves the mechanical strength of the vapor chamber 1 when the sealed space 3 is decompressed. The wall surface 33 of the upper steam flow path recess 32 described above forms the side wall of the upper flow path protrusion 34.

[0074] In this embodiment, the upper flow passage protrusions 34 are arranged in a staggered manner in a plan view. This allows the vapor of the working fluid 2 to flow around the upper flow passage protrusions 34, thereby preventing the flow of the vapor from being obstructed. The planar shape of the upper surface 34a of the upper flow passage protrusions 34 is circular, which also prevents the flow of the vapor of the working fluid 2 from being obstructed. The planar shape of the upper flow passage protrusions 34 is not limited to a circular shape as long as the vapor of the working fluid 2 can be smoothly diffused.

[0075] 3 and 5, a lower liquid flow path section 40 (liquid flow path section) through which the liquid working fluid 2 passes is provided on the lower surface 30a of the wick sheet 30. This lower liquid flow path section 40 constitutes a part of the sealed space 3 described above, and is in communication with the upper steam flow path recess 32.

[0076] The lower liquid flow passage section 40 has a plurality of mainstream grooves 41. As shown in FIG. 5 and FIG. 6, each mainstream groove 41 is formed to extend in a first direction X (the longitudinal direction of the vapor chamber 1, the left-right direction in FIG. 5), and is configured to mainly pass the liquid working fluid 2. As a result, the mainstream groove 41 is configured to transport the liquid working fluid 2 condensed from the vapor of the working fluid 2 to the evaporation section 31. The mainstream grooves 41 are disposed at equal intervals in a second direction Y perpendicular to the first direction X. In the second direction Y, the width w1 of the mainstream groove 41 is smaller than the gap G (the gap on the upper surface 30b, see FIG. 3) between the adjacent upper flow passage protrusions 34. For example, the gap G is 500 μm to 1500 μm, and the width w1 of the mainstream groove 41 is 5 μm to 500 μm. The depth h1 (vertical direction in FIG. 7) of the main groove 41 is shallower than the depth of the communicating recess 35 (described later), and is, for example, about 50 μm. The same is true for the connecting groove 45 (described later). The width w1 of the main groove 41 refers to the dimension at the lower surface 30a.

[0077] The main groove 41 is formed by etching from the lower surface 30a of the wick sheet 30 in an etching process described below. As a result, the main groove 41 has a wall surface 42 formed in a curved shape, as shown in Fig. 7. This wall surface 42 defines the main groove 41 and is curved in a shape that bulges toward the upper surface 30b.

[0078] As shown in FIG. 6, a convex row 43 is provided between adjacent main grooves 41. Each convex row 43 includes a plurality of convex portions 44 arranged in a first direction X. Each convex portion 44 is formed in a rectangular shape such that the first direction X is the longitudinal direction in a plan view. A communication groove 45 is interposed between adjacent convex portions 44. The communication groove 45 is formed to extend in the second direction Y and connects adjacent main grooves 41 to each other. This allows the working fluid 2 to move between these main grooves 41.

[0079] The protrusions 44 are not etched in the etching process described below, and the material of the wick sheet 30 remains. In this embodiment, as shown in FIG. 6, the planar shape of the protrusions 44 (the shape at the position of the lower surface 30a of the wick sheet 30) is rectangular. The positions of the protrusions 44 of each protrusion row 43 in the first direction X are the same. As a result, the communication grooves 45 of adjacent protrusion rows 43 are arranged at the same positions in the first direction X, and the multiple main grooves 41 and the multiple communication grooves 45 are arranged in a lattice pattern. The width w2 of the protrusions 44 is preferably, for example, 5 μm to 500 μm.

[0080] 3 to 5, the upper vapor flow passage recess 32 and the mainstream groove 41 of the lower liquid flow passage section 40 may be communicated with each other by a plurality of communication recesses 35 (communication sections). As a result, the liquid working fluid 2 generated by condensation of the vapor of the working fluid 2 in the upper vapor flow passage recess 32 passes through the communication recesses 35 and flows into the mainstream groove 41 of the lower liquid flow passage section 40.

[0081] The communication recess 35 is formed in a concave shape on the lower surface 30a by etching from the lower surface 30a of the wick sheet 30 in an etching process described later. As a result, the communication recess 35 has a wall surface 36 formed in a curved shape as shown in FIG. 3. The wall surface 36 defines the communication recess 35 and is curved in a shape that bulges toward the upper surface 30b. The wall surface 36 is connected to the wall surface 33 of the upper steam flow path recess 32. That is, the wall surface 36 of the communication recess 35 and the wall surface 33 of the upper steam flow path recess 32 are connected to form a through portion 37, and the wall surface 36 and the wall surface 33 are each curved toward the through portion 37. As a result, the communication recess 35 communicates with the upper steam flow path recess 32. In this embodiment, an example is shown in which the planar shape of the through portion 37 is circular. The diameter of the through portion 37 is, for example, 5 μm to 1000 μm. The position of the through portion 37 in the thickness direction of the wick sheet 30 (the vertical direction in Figure 3) may be midway between the lower surface 30a and the upper surface 30b, or may be shifted downward or upward from the midway position, and is arbitrary as long as the upper steam flow path recess 32 and the communication recess 35 are connected to each other.

[0082] In Fig. 6, some of the plurality of main grooves 41 are divided by the communication recess 35. In the present embodiment, other of the plurality of main grooves 41 are not divided by the communication recess 35 and are continuously formed from one end to the other end of the wick sheet 30 in the first direction X. This improves the transportability of the liquid working fluid 2 to the evaporation section 31. However, this is not limited to the above, and as long as the main grooves 41 are connected to each other by the communication grooves 45, there may be no main groove 41 continuously formed from one end to the other end of the wick sheet 30.

[0083] Each of the communication recesses 35 is in contact with and communicates with the plurality of mainstream grooves 41. This allows the liquid working fluid 2 that has passed through the communication recesses 35 to easily enter the plurality of mainstream grooves 41. More specifically, the communication recesses 35 on the lower surface 30a of the wick sheet 30 are formed so as to cross the plurality of mainstream grooves 41 arranged side by side in the second direction Y. However, this is not limited thereto, and the communication recesses 35 may be in contact with one mainstream groove 41. Furthermore, the communication recesses 35 may be in contact with the communication groove 45 and communicate with the mainstream groove 41 via the communication groove 45.

[0084] As shown in Fig. 4 to Fig. 6, the communication recesses 35 are arranged at intervals in plan view. In this embodiment, the communication recesses 35 are evenly arranged over the entire wick sheet 30, and are arranged between the upper flow path protrusions 34 adjacent to each other in plan view. In this manner, the communication recesses 35 are arranged in a staggered manner in plan view. The planar shape of the communication recesses 35 on the lower surface 30a of the wick sheet 30 is formed in a circular shape, but is not limited thereto. For example, the diameter of the communication recesses 35 (diameter on the lower surface 30a, see Fig. 3) is 100 µm to 3000 µm.

[0085] 3 shows a cross-sectional view of line AA in FIG. 2, and this cross-section shows a cross-section including the centers of a pair of upper flow path protrusions 34 adjacent to the through-hole 37 on both sides of the through-hole 37 in the Y direction. In the cross-section shown in FIG. 3, it is preferable that the width w4 of the through-hole 37 (corresponding to the diameter of the through-hole 37 described above) is smaller than the gap G between the pair of upper flow path protrusions 34 and / or the width w5 of the corresponding communicating recess 35 (corresponding to the diameter of the communicating recess 35 described above). In FIG. 3, the width of the through-hole 37 is smaller than the gap G and is smaller than the width of the communicating recess 35. Here, the gap G means the gap on the upper surface 30b, and the width of the communicating recess 35 means the width on the lower surface 30a.

[0086] As described above, the lower liquid flow path section 40 is formed on the lower surface 30a of the wick sheet 30. On the other hand, the upper surface 10b of the lower metal sheet 10 is formed flat. As a result, each of the main stream grooves 41 of the lower liquid flow path section 40 is covered with the flat upper surface 10b. In this case, as shown in FIG. 7, the wall surface 42 of the main stream groove 41 and the upper surface 10b of the lower metal sheet 10 can form two right-angled or acute-angled corners 38, and the capillary action at these two corners 38 can be enhanced. That is, when the main stream groove 41 is formed by etching, the wall surface 42 of the main stream groove 41 tends to be formed in a curved shape as described above. Therefore, by forming the upper surface 10b of the lower metal sheet 10 flat so as to cover the main stream groove 41, the capillary action at the corners 38 shown in FIG. 7 can be enhanced. Like the main groove 41, the connecting groove 45 is also covered by the upper surface 10b of the lower metal sheet 10, so that the capillary action can be enhanced by similar corners.

[0087] The lower metal sheet 10 and the upper metal sheet 20 are permanently bonded by diffusion bonding via a spacer member 50. That is, the spacer member 50 is interposed between the lower peripheral edge portion 12 of the lower metal sheet 10 and the upper peripheral edge portion 21 of the upper metal sheet 20. The spacer member 50 has a lower surface 50a that abuts against the lower peripheral edge portion 12 of the lower metal sheet 10 and an upper surface 50b that abuts against the upper peripheral edge portion 21 of the upper metal sheet 20. The upper surface 10b at the lower peripheral edge portion 12 of the lower metal sheet 10 and the lower surface 50a of the spacer member 50 are diffusion bonded, and the lower surface 20a at the upper peripheral edge portion 21 of the upper metal sheet 20 and the upper surface 50b of the spacer member 50 are diffusion bonded. The spacer member 50, like the lower peripheral portion 12 and the upper peripheral portion 21, is formed around the entire periphery of the wick sheet 30, and is formed in a rectangular frame shape so as to fit along the metal sheets 10 and 20. In this way, the sealed space 3 formed by the upper steam flow path recess 32 and the lower liquid flow path portion 40 of the wick sheet 30 is sealed by the lower metal sheet 10, the upper metal sheet 20, and the spacer member 50. Note that the lower metal sheet 10 and the spacer member 50, and the upper metal sheet 20 and the spacer member 50 may be joined by other methods such as brazing instead of diffusion bonding, as long as they can be permanently joined. In addition, the planar shape of the spacer member 50 is arbitrary as long as it is formed so as to fit along the metal sheets 10 and 20.

[0088] The spacer member 50 further has an inner surface 50c that abuts against the outer surface 30c of the wick sheet 30. The inner surface 50c is formed to extend from the lower surface 50a to the upper surface 50b. Between the inner surface 50c of the spacer member 50 and the outer surface 30c of the wick sheet 30, no gap is formed through which the vapor of the working liquid 2 or the liquid working liquid 2 can pass.

[0089] The upper surface 10b of the lower metal sheet 10 and the lower surface (corresponding to the lower surface 30a) of the convex portion 44 of the wick sheet 30 are in contact with each other but are not joined. However, no gap through which the vapor of the working liquid 2 or the liquid working liquid 2 can pass is formed between the upper surface 10b of the lower metal sheet 10 and the lower surface of the convex portion 44 of the wick sheet 30. Similarly, the lower surface 20a of the upper metal sheet 20 and the upper surface 34a (corresponding to the upper surface 30b) of the upper flow path protrusion 34 of the wick sheet 30 are in contact with each other but are not joined. However, no gap through which the vapor of the working liquid 2 or the liquid working liquid 2 can pass is formed between the lower surface 20a of the upper metal sheet 20 and the upper surface 34a of the upper flow path protrusion 34 of the wick sheet 30.

[0090] The materials used for the lower metal sheet 10, the upper metal sheet 20, and the wick sheet 30 are preferably materials with good thermal conductivity. For example, the lower metal sheet 10, the upper metal sheet 20, and the wick sheet 30 are preferably made of a metal material such as copper (oxygen-free copper) or a copper alloy. This can increase the thermal conductivity of the lower metal sheet 10, the upper metal sheet 20, and the wick sheet 30. Therefore, the heat transport efficiency of the vapor chamber 1 can be increased. Since the heat transport from the lower metal sheet 10 to the upper metal sheet 20 is mainly realized by the working fluid 2, the wick sheet 30 may be made of a material different from the lower metal sheet 10 and the upper metal sheet 20 and may have a lower thermal conductivity than the metal sheets 10 and 20. In addition, the lower metal sheet 10, the upper metal sheet 20, and the wick sheet 30 may be made of a material other than a metal material as long as the heat transport function can be ensured.

[0091] Any material may be used for the spacer member 50 as long as it can be suitably diffusion-bonded to the lower metal sheet 10 and the upper metal sheet 20. When the same material as that of the lower metal sheet 10 and the upper metal sheet 20 is used for the spacer member 50, the spacer member 50 can also function as a heat transport member, and the heat transport efficiency of the vapor chamber 1 can be improved.

[0092] The thickness of the vapor chamber 1 is, for example, 150 μm to 2700 μm. The thickness T1 of the lower metal sheet 10 and the thickness T2 of the upper metal sheet 20 are, for example, 5 μm to 1000 μm, but are preferably 10 μm or more in terms of handling and the like. The thickness T3 of the wick sheet 30 is, for example, 50 μm to 700 μm, and preferably 100 μm to 700 μm. The thickness of the spacer member 50 is the same as the thickness T3 of the wick sheet 30. FIG. 2 shows a case where the thickness T1 of the lower metal sheet 10 and the thickness T2 of the upper metal sheet 20 are equal, but this is not limited thereto, and the thickness T1 of the lower metal sheet 10 and the thickness T2 of the upper metal sheet 20 may not be equal.

[0093] Next, a method for manufacturing the vapor chamber 1 of the present embodiment having such a configuration will be described with reference to Figures 8 to 18. Note that Figures 8 to 18 show the same cross section as the cross section of Figure 3.

[0094] First, the process of producing the wick sheet 30 will be described.

[0095] First, as shown in FIG. 8, in a preparation step, a flat metal material sheet M is prepared.

[0096] 9, in a resist formation step, a lower resist film 60 is formed on the lower surface Ma of the metal material sheet M, and an upper resist film 61 is formed on the upper surface Mb. Prior to forming the resist films 60, 61, it is preferable that the lower surface Ma and the upper surface Mb of the metal material sheet M are subjected to an acidic degreasing treatment as a pretreatment.

[0097] Next, as shown in FIG. 10, in the patterning step, the lower resist film 60 and the upper resist film 61 are patterned by photolithography. In this case, a first resist opening 62 corresponding to the main stream groove 41 and the communication groove 45 of the lower liquid flow path section 40 is formed in the lower resist film 60, and a second resist opening 63 corresponding to the communication recess 35 is formed. Among them, the first resist opening 62 is preferably formed to be smaller than the width of the main stream groove 41 and the width of the communication groove 45 on the lower surface 30a of the wick sheet 30. For example, when forming the main stream groove 41 having a width w1 of 70 μm to 150 μm, the width w3 of the first resist opening 62 is preferably 20 μm to 100 μm. On the other hand, the second resist opening 63 is preferably formed in the same shape as the planar shape of the communication recess 35 on the lower surface 30a of the wick sheet 30. Also, a third resist opening 64 corresponding to the upper vapor flow path recess 32 is formed in the upper resist film 61. The third resist opening 64 is preferably formed in the same shape as the planar shape of the upper steam flow path recess 32 on the upper surface 30b of the wick sheet 30. In this case, the upper resist film 61 in which the third resist opening 64 is formed is formed in the same shape as the planar shape of the upper surface 34a of the upper flow path protrusion 34.

[0098] 11, in an etching step, the lower surface Ma and the upper surface Mb of the metal material sheet M are etched. As a result, the portions of the lower surface Ma of the metal material sheet M that correspond to the first resist opening 62 and the second resist opening 63 are etched, and the main groove 41 and the communication groove 45 of the lower liquid flow path portion 40, as well as the communicating recess 35, are formed as shown in FIG.

[0099] Here, as described above, the first resist opening 62 is formed smaller than the width of the main groove 41 and the width of the communication groove 45 on the lower surface 30a of the wick sheet 30. This reduces the amount of etching liquid that enters the first resist opening 62, and the etching rate of the portion of the lower surface Ma of the metal material sheet M that corresponds to the first resist opening 62 decreases. Therefore, the depth of the main groove 41 and the communication groove 45 formed by the first resist opening 62 can be made shallow. On the other hand, the second resist opening 63 is formed in a shape equivalent to the planar shape of the communication recess 35 on the lower surface 30a of the wick sheet 30. This ensures the amount of etching liquid that enters the second resist opening 63, and the depth of the communication recess 35 formed by the second resist opening 63 can be made deep.

[0100] In the etching process, the upper surface Mb of the metal material sheet M is also etched at the same time, and the portions of the upper surface Mb corresponding to the third resist openings 64 are etched to form the upper steam flow path recesses 32 as shown in Fig. 11. Here, as described above, the third resist openings 64 are formed in a shape equivalent to the planar shape of the upper steam flow path recesses 32 on the upper surface 30b of the wick sheet 30. This ensures that the amount of etching liquid that enters the third resist openings 64 is sufficient, and the depth of the upper steam flow path recesses 32 formed by the third resist openings 64 can be increased.

[0101] In the etching process, the peripheral portion of the metal material sheet M is etched from the lower surface Ma and the upper surface Mb to obtain a predetermined outer contour shape as shown in Fig. 4 and Fig. 5. That is, the outer surface 30c of the wick sheet 30 is formed. As the etching solution, for example, an iron chloride-based etching solution such as a ferric chloride aqueous solution, or a copper chloride-based etching solution such as a copper chloride aqueous solution can be used.

[0102] After the etching step, as shown in FIG. 12, a resist removal step is performed in which the lower resist film 60 and the upper resist film 61 are removed.

[0103] In this manner, the wick sheet manufacturing process is completed, and the wick sheet 30 according to the present embodiment can be obtained.

[0104] After the wick sheet preparation step, as shown in FIG. 13, an assembly step is performed in which the lower metal sheet 10, the upper metal sheet 20, the wick sheet 30 and the spacer member 50 are assembled.

[0105] In this case, first, a lower metal sheet 10 and an upper metal sheet 20 are prepared as shown in Figures 2 and 3. Of these, it is preferable that an injection hole 22 is formed in advance in the upper metal sheet 20 by etching, cutting, punching or the like.

[0106] Next, the wick sheet 30 and the spacer member 50 are placed on the lower metal sheet 10. At this time, the lower surface 30a of the wick sheet 30 is abutted against the upper surface 10b of the lower metal sheet 10. The spacer member 50 is arranged around the wick sheet 30, and the lower surface 50a of the spacer member 50 is abutted against the upper surface 10b at the lower peripheral portion 12 of the lower metal sheet 10. In addition, the inner surface 50c of the spacer member 50 is abutted against the outer surface 30c of the wick sheet 30. Here, the upper surface 10b of the lower metal sheet 10 does not have a steam flow path through which the vapor of the working liquid 2 passes, or a liquid flow path through which the liquid working liquid 2 passes. For this reason, the alignment of the lower metal sheet 10 and the wick sheet 30 may be performed to the extent that the outer edge of the lower metal sheet 10 and the outer edge of the spacer member 50 can be aligned, and the alignment can be simplified.

[0107] Next, the upper metal sheet 20 is placed on the wick sheet 30 and the spacer member 50. In this case, the lower surface 20a of the upper metal sheet 20 is abutted against the upper surface 30b of the wick sheet 30. Also, the lower surface 20a of the upper peripheral portion 21 of the upper metal sheet 20 is abutted against the upper surface 50b of the spacer member 50. Here, the lower surface 20a of the upper metal sheet 20 does not have a vapor flow path through which the vapor of the working fluid 2 passes, or a liquid flow path through which the liquid working fluid 2 passes. For this reason, the upper metal sheet 20 and the wick sheet 30 need only be aligned to the extent that the outer edge of the upper metal sheet 20 and the outer edge of the spacer member 50 can be aligned, and the alignment can be simplified.

[0108] In this manner, a sheet assembly 65 is obtained in which the wick sheet 30 and the spacer member 50 are interposed between the lower metal sheet 10 and the upper metal sheet 20.

[0109] After the assembly process, as shown in FIG. 14, the lower metal sheet 10, the upper metal sheet 20, and the spacer member 50 of the sheet assembly 65 are temporarily fixed as a temporary fixing process. In this case, the lower metal sheet 10, the upper metal sheet 20, and the spacer member 50 are fixed. The fixing method is not particularly limited, but for example, the lower metal sheet 10 and the upper metal sheet 20 may be fixed to each other by resistance welding via the spacer member 50. In this case, as shown in FIG. 14, it is preferable to perform resistance welding in spots using an electrode rod 66. Laser welding may be performed instead of resistance welding.

[0110] After the temporary fixing process, as shown in Fig. 15, the lower metal sheet 10 and the upper metal sheet 20 are permanently bonded to each other by diffusion bonding via the spacer member 50 as a bonding process. Diffusion bonding is a method in which the lower metal sheet 10 and the spacer member 50, and the upper metal sheet 20 and the spacer member 50 to be bonded are brought into close contact with each other, and the lower metal sheet 10, the upper metal sheet 20, and the spacer member 50 are pressurized and heated in a direction in which they are brought into close contact with each other in a controlled atmosphere such as a vacuum or an inert gas, thereby bonding them by utilizing the diffusion of atoms that occurs on the bonding surface. In diffusion bonding, the materials of the lower metal sheet 10, the upper metal sheet 20, and the spacer member 50 are heated to a temperature close to the melting point, but lower than the melting point, so that it is possible to avoid the metal sheets 10, 20, and the spacer member 50 from melting and deforming.

[0111] Through the joining process, the upper surface 10b of the lower peripheral portion 12 of the lower metal sheet 10 is diffusion-bonded to the lower surface 50a of the spacer member 50. Also, the lower surface 20a of the upper peripheral portion 21 of the upper metal sheet 20 is diffusion-bonded to the upper surface 50b of the spacer member 50. As a result, the lower metal sheet 10, the upper metal sheet 20, and the spacer member 50 form a sealed space 3.

[0112] After the joining step, a filling step is performed in which the hydraulic fluid 2 is filled into the sealed space 3. The filling step includes a vacuuming step, a filling step, and a sealing step.

[0113] 16, in the evacuation step, the sealed space 3 is evacuated to a vacuum, whereby the sealed space 3 is depressurized.

[0114] 17, as an injection step, the hydraulic fluid 2 is injected into the sealed space 3. The hydraulic fluid 2 is injected into the sealed space 3 through an injection hole 22 provided in the upper metal sheet 20.

[0115] After the injection step, as shown in FIG. 18, the injection hole 22 is sealed as a sealing step. In this case, first, the amount of the working fluid 2 injected into the sealed space 3 is adjusted. More specifically, the sheet assembly 65 is heated as a whole, the injected working fluid 2 is vaporized, and a part of the vapor of the working fluid 2 is discharged from the sealed space 3. Next, when the amount of the working fluid 2 remaining in the sealed space 3 is reduced to a predetermined amount, a sealing member 23 is attached to the injection hole 22. Thereafter, the sealing member 23 is joined to the injection hole 22 by, for example, laser welding. In this manner, the injection hole 22 is sealed. As a result, communication between the sealed space 3 and the outside air is blocked, the working fluid 2 is sealed in the sealed space 3, and the working fluid 2 in the sealed space 3 is prevented from leaking to the outside. When the temperature of the sheet assembly 65 drops to room temperature, the pressure in the sealed space 3 drops to a pressure close to a vacuum. This allows the working fluid 2 sealed in the sealed space 3 to evaporate at a temperature lower than 100° C. when it receives heat from the device D, thereby improving the heat transport efficiency.

[0116] In this manner, the production of the vapor chamber 1 is completed, and the vapor chamber 1 according to the present embodiment is obtained.

[0117] Next, a method for operating the vapor chamber 1, that is, a method for cooling the device D, will be described.

[0118] The vapor chamber 1 obtained as described above is installed in a housing of a mobile terminal or the like, and a device D, such as a CPU, which is an apparatus to be cooled, is attached to the lower surface 10a of the lower metal sheet 10. Since the amount of the working fluid 2 injected into the sealed space 3 is small, the liquid working fluid 2 in the sealed space 3 adheres to the wall surfaces of the sealed space 3, i.e., the wall surface 33 of the upper vapor flow path recess 32, the wall surface 36 of the communication recess 35, and the wall surface 42 of the main flow path groove 41 and the wall surface 46 of the communication groove 45 of the lower liquid flow path section 40 (see FIG. 20) due to its surface tension. The working fluid 2 also adheres to the parts of the upper surface 10b of the lower metal sheet 10 exposed to the communication recess 35, the main flow path groove 41, and the communication groove 45, and the parts of the lower surface 20a of the upper metal sheet 20 exposed to the upper vapor flow path recess 32.

[0119] In this state, when the device D generates heat, the working fluid 2 present in the evaporation section 31 (see Figs. 4 and 5) of the upper steam flow recess 32 receives heat from the device D via the heat receiving section 11 (see Figs. 2 and 3) of the lower metal sheet 10. The received heat is absorbed as latent heat, and the working fluid 2 evaporates (vaporizes), generating steam of the working fluid 2. Most of the generated steam diffuses within the upper steam flow recess 32 constituting the sealed space 3 (see the solid arrow in Fig. 4). The steam within the upper steam flow recess 32 leaves the evaporation section 31, and most of the steam is transported to the peripheral portion of the wick sheet 30, which has a relatively low temperature. The diffused steam is cooled by radiating heat mainly to the upper metal sheet 20. The heat received by the upper metal sheet 20 from the steam is transferred to the outside air via the housing member Ha (see Fig. 3).

[0120] The steam radiates heat to the upper metal sheet 20, and loses the latent heat absorbed in the evaporation section 31, and is condensed. The condensed liquid working fluid 2 adheres to the wall surface 33 of the upper vapor flow path recess 32 and the lower surface 20a of the upper metal sheet 20. Here, since the working fluid 2 continues to evaporate in the evaporation section 31, the working fluid 2 in the portion of the lower liquid flow path section 40 other than the evaporation section 31 is transported toward the evaporation section 31 (see the dashed arrow in FIG. 5). As a result, the liquid working fluid 2 adhered to the wall surface 33 of the upper vapor flow path recess 32 and the lower surface 20a of the upper metal sheet 20 moves to the lower liquid flow path section 40 through the wall surface 36 of the communication recess 35. Then, the liquid working fluid 2 enters the main stream grooves 41 of the lower liquid flow path section 40, and the main stream grooves 41 and the communication grooves 45 are filled with the liquid working fluid 2. Therefore, the filled working fluid 2 obtains a propulsive force toward the evaporation section 31 due to the capillary action of each main groove 41 and each communication groove 45 , and is smoothly transported toward the evaporation section 31 .

[0121] In the lower liquid flow path section 40, each mainstream groove 41 communicates with the adjacent other mainstream grooves 41 via the corresponding communication grooves 45. This allows the liquid working fluid 2 to flow between the adjacent mainstream grooves 41, suppressing the occurrence of dryout in the mainstream grooves 41. As a result, a capillary action is imparted to the working fluid 2 in each mainstream groove 41, and the working fluid 2 is smoothly transported toward the evaporation section 31.

[0122] The working liquid 2 that has reached the evaporation section 31 receives heat from the device D again via the heat receiving section 11 of the lower metal sheet 10 and evaporates. The vapor of the evaporated working liquid 2 passes through the communication groove 45 and the communication recess 35 and moves to the upper vapor flow path recess 32, which has a large flow path cross-sectional area, and diffuses within the upper vapor flow path recess 32. In this way, the working liquid 2 circulates within the sealed space 3 while repeatedly changing phases, i.e., evaporating and condensing, to transport and release the heat of the device D. As a result, the device D is cooled.

[0123] Thus, according to this embodiment, the upper surface 30b of the wick sheet 30 interposed between the lower metal sheet 10 and the upper metal sheet 20 is provided with the upper steam flow path recess 32 through which the vapor of the working fluid 2 passes, and the lower surface 30a is provided with the lower liquid flow path section 40 through which the liquid working fluid 2 passes. This makes it possible to eliminate the need for etching the lower metal sheet 10 and the upper metal sheet 20 to form the steam flow path and the liquid flow path. That is, the number of members to be etched can be reduced. This simplifies the manufacturing process of the vapor chamber 1, and the vapor chamber 1 can be easily manufactured. In addition, since the upper steam flow path recess 32 and the lower liquid flow path section 40 are formed in the wick sheet 30, the upper steam flow path recess 32 and the lower liquid flow path section 40 can be accurately positioned during the etching process. This makes it possible to eliminate the need to align the upper steam flow path recess 32 and the lower liquid flow path section 40 in the assembly process. As a result, the vapor chamber 1 can be easily manufactured.

[0124] According to this embodiment, the lower surface 30a of the wick sheet 30 is provided with a lower liquid flow passage section 40 through which the liquid working fluid 2 passes, and the upper surface 30b is provided with an upper vapor flow passage recess 32 through which the vapor of the working fluid 2 passes. This allows the lower liquid flow passage section 40 to be disposed on the lower metal sheet 10 side, and the upper vapor flow passage recess 32 to be disposed on the upper metal sheet 20 side. Therefore, the heat received from the heat receiving section 11 of the lower metal sheet 10 can be effectively used for the evaporation of the working fluid 2, and the vapor of the working fluid 2 can be effectively dissipated to the upper metal sheet 20. As a result, the heat transport efficiency of the vapor chamber 1 can be improved.

[0125] Furthermore, according to this embodiment, a spacer member 50 is interposed between the lower peripheral edge portion 12 of the lower metal sheet 10 and the upper peripheral edge portion 21 of the upper metal sheet 20. This allows the lower metal sheet 10 and the upper metal sheet 20 to be diffusion bonded via the spacer member 50, improving the bonding strength. This allows the lower metal sheet 10 and the upper metal sheet 20 to be diffusion bonded while maintaining a simple flat shape.

[0126] According to this embodiment, the upper surface 10b of the lower metal sheet 10 is formed flat. This allows the main stream grooves 41 of the lower liquid flow path section 40 to be covered by the flat upper surface 10b. This allows two right-angled or acute-angled corners 38 (see FIG. 7) to be formed in the cross section of the main stream groove 41, enhancing the capillary action acting on the working fluid 2 in each main stream groove 41. This allows the working fluid 2 in the main stream groove 41 to be given a propulsive force toward the evaporation section 31, allowing the working fluid 2 to be smoothly transported toward the evaporation section 31. The capillary action can be enhanced in each communication groove 45 in the same manner.

[0127] Moreover, according to this embodiment, the upper steam flow passage recess 32 communicates with the lower liquid flow passage section 40 via the communication recess 35. This allows the liquid working fluid 2 condensed in the upper steam flow passage recess 32 to move smoothly through the communication recess 35 to the lower liquid flow passage section 40. This allows the liquid working fluid 2 to be transported smoothly to the evaporation section 31. Particularly, according to this embodiment, the communication recess 35 contacts and communicates with the multiple main stream grooves 41 of the lower liquid flow passage section 40. This allows the liquid working fluid 2 that has passed through the communication recess 35 to smoothly enter the multiple main stream grooves 41. This allows the liquid working fluid 2 to be transported even more smoothly to the evaporation section 31.

[0128] Furthermore, according to this embodiment, the wall surface 33 defining the upper vapor flow path recess 32 and the wall surface 36 defining the communication recess 35 are curved toward the through portion 37. As a result, the upper vapor flow path recess 32 and the communication recess 35 can be formed by etching from the lower surface 30a of the wick sheet 30 and from the upper surface 30b, and the lower liquid flow path portion 40 and the upper vapor flow path recess 32 can be easily connected to each other.

[0129] According to this embodiment, in the cross section shown in FIG. 3, the width of the through-portion 37 is smaller than the gap G between the pair of upper flow passage protrusions 34 on both sides of the through-portion 37 and / or the width of the corresponding communication recess 35. This makes it possible to ensure the distance between the adjacent through-portions 37, and to increase the strength of the wick sheet 30. Furthermore, the vapor of the working fluid 2 evaporated in the evaporator 31 passes through the through-portion 37 formed to be constricted and reaches the upper vapor flow passage recess 32. At this time, since the flow passage cross-sectional area of ​​the vapor of the working fluid 2 expands when passing through the through-portion 37, the vapor of the working fluid 2 can be diffused vigorously into the upper vapor flow passage recess 32. This improves the heat transport efficiency.

[0130] Furthermore, according to this embodiment, a plurality of upper flow passage protrusions 34 are provided in the upper steam flow passage recess 32, protruding from the bottom of the wall surface 33 of the upper steam flow passage recess 32 and contacting the lower surface 20a of the upper metal sheet 20. This makes it possible to prevent the upper metal sheet 20 from being deformed by the pressure of the outside air when the sealed space 3 is depressurized, and improves the mechanical strength of the vapor chamber 1. In particular, according to this embodiment, the plurality of upper flow passage protrusions are arranged in a staggered pattern in a plan view, which makes it possible to further prevent the upper metal sheet 20 from being deformed when the sealed space 3 is depressurized, and also makes it possible to suppress obstruction of the flow of the vapor of the working fluid 2.

[0131] Furthermore, according to the present embodiment, the communication recess 35 is disposed between the adjacent upper flow path protrusions 34 in a plan view. This makes it possible to effectively prevent the mechanical strength of the vapor chamber 1 from being reduced.

[0132] (First Modification) In the above-described embodiment, an example has been described in which the width and depth of the communication groove 45 are the same as those of the main groove 41. However, this is not limited to this. For example, as shown in Figs. 19 to 21, the width of the communication groove 45 may be larger than the width of the main groove 41. The modified examples shown in Figs. 19 to 21 will be described below.

[0133] As shown in FIG. 19, the main groove 41 includes an intersection portion P where the communication grooves 45 communicate with each other, and a main groove main portion 41a.

[0134] Among these, at the intersection P, a pair of communication grooves 45 located on both sides of the mainstream groove 41 in the second direction Y communicate with the mainstream groove 41. The pair of communication grooves 45 are aligned in the second direction Y and arranged in a straight line. In this way, at the intersection P, the mainstream groove 41 and the communication groove 45 intersect in a cross shape. The intersection P is a region between adjacent mainstream groove main bodies 41a in the first direction X, and is also a region between adjacent communication grooves 45 in the second direction Y. In other words, it is a region where the mainstream groove 41 and the row of communication grooves 45 intersect (i.e., overlap).

[0135] The main groove body portions 41a are disposed at positions different from the intersection portions P in the first direction X, and are portions located between adjacent protrusions 44 in the second direction Y. The intersection portions P and the main groove body portions 41a are disposed alternately.

[0136] The width w1 (dimension in the second direction Y) of the mainstream grooves 41 may be larger than the width w2 (dimension in the second direction Y) of the convex portions 44. In this case, the proportion of the mainstream grooves 41 in the lower surface 30a of the wick sheet 30 can be increased. This increases the flow channel density of the mainstream grooves 41 in the lower surface 30a, thereby improving the transport function of the liquid working fluid 2. For example, the width w1 of the mainstream grooves 41 may be 30 μm to 200 μm, and the width w2 of the convex portions 44 may be 20 μm to 180 μm.

[0137] The width w3 of the communication groove 45 may be larger than the width w1 (more specifically, the width of the main groove body portion 41a) of the mainstream groove 41. The width w3 of the communication groove 45 may be, for example, 40 μm to 300 μm.

[0138] The cross-sectional shape (cross-section in the second direction Y) of the main groove 41 is not particularly limited, and may be, for example, rectangular, curved, semicircular, or V-shaped. The cross-sectional shape (cross-section in the first direction X) of the communication groove 45 is similar. In Figs. 20 and 21, an example is shown in which the main groove 41 and the communication groove 45 are each formed to have a curved cross-section. In this case, the widths of the main groove 41 and the communication groove 45 are the widths of the grooves on the lower surface 30a of the wick sheet 30. Similarly, the width of the protrusions 44 is the width of the protrusions on the lower surface 30a.

[0139] In FIG. 19, each of the convex portions 44 is formed in a rectangular shape so that the first direction X is the longitudinal direction in a plan view when viewed from a broad perspective. The convex portions 44 may be formed in the same shape throughout the lower liquid flow path portion 40. However, a rounded curved portion 47 is provided at the corner of each of the convex portions 44. This allows the corner of each of the convex portions 44 to be smoothly curved, thereby reducing the flow path resistance of the liquid working fluid 2. In addition, an example is shown in which two curved portions 47 are provided at the right end and the left end of the convex portion 44 in FIG. 19, and a straight portion 48 is provided between these two curved portions 47. For this reason, the width w3 of the communication groove 45 is the distance between the straight portions 48 of the convex portions 44 adjacent to each other in the first direction X. Although not shown, the same applies to the case where the curved portions 47 are not formed at the corners of each of the convex portions 44. However, the end shape of the convex portion 44 is not limited to this. For example, the right end and the left end may be entirely curved (e.g., semicircular) without being provided with the straight portion 48. In this case, the width w3 of each communication groove 45 is the minimum distance between adjacent protrusions 44 in the first direction X.

[0140] 20 and 21, in this modification, the depth h3 of the communication groove 45 may be deeper than the depth h1 of the main groove 41 (more specifically, the depth of the main groove body 41a). As described above, when the cross-sectional shape of each main groove 41 and the cross-sectional shape of each communication groove 45 are curved, the depth of the grooves 41, 45 is the depth at the deepest position of the groove. The depth h3 of the communication groove 45 may be, for example, 10 μm to 250 μm.

[0141] In this modification, as shown in Fig. 21, the depth h1' of the intersection P of the main groove 41 may be deeper than the depth h1 of the main groove body 41a. The depth h1' of the intersection P of the main groove 41 may be deeper than the depth h3 of the connecting groove 45. The depth h1' of such an intersection P may be, for example, 20 µm to 300 µm. The depth h1' of the intersection P is the depth at the deepest position of the intersection P.

[0142] As described above, the depth h3 of the communication groove 45 may be deeper than the depth h1 of the main body 41a of the main groove 41, and the depth h1' of the intersection P of the main groove 41 may be deeper than the depth h1 of the main body 41a. As a result, a buffer region Q deeper than the depth h1 of the main body 41a is formed in the region from the intersection P to the intersection P via the communication groove 45. This buffer region Q is capable of storing the liquid working fluid 2. Usually, the main grooves 41 and the communication grooves 45 of the lower liquid flow path portion 40 are filled with the liquid working fluid 2. Therefore, since the depths (h1' and h3) of the buffer region Q are deeper than the depth h1 of the main body 41a of the main groove 41a, it is possible to store a large amount of the working fluid 2 in the buffer region Q. As described above, the main grooves 41 and the communication grooves 45 are filled with the working fluid 2, so that the working fluid 2 can be stored in the buffer region Q regardless of the attitude of the vapor chamber 1. In this modified example, since the connection grooves 45 are aligned in the second direction Y, the buffer region Q is formed so as to extend continuously in the second direction Y.

[0143] In addition, a large number of intersections P are formed in the lower liquid flow path portion 40 of the vapor chamber 1, and if the depth h1' of at least one of the intersections P is deeper than the depth h1 of the main mainstream groove body portion 41a (or the depth h3 of the communication groove 45), the storage performance of the working fluid 2 at the intersection P can be improved. This storage performance improves as the number of intersections P having a depth h1' deeper than the depth h1 of the main mainstream groove body portion 41a increases, so it is preferable that the depth h1' of all intersections P have the same depth. However, it is clear that the storage performance of the working fluid 2 can be improved even if the depth h1' of some intersections P is not deeper than the depth h1 of the main mainstream groove body portion 41a due to manufacturing errors, etc. The same applies to the depth h3 of the communication groove 45.

[0144] Here, a method for checking the width and depth of the mainstream groove 41 and the width and depth of the connecting groove 45 from the completed vapor chamber 1 will be described. Generally, the mainstream groove 41 and the connecting groove 45 are not visible from the outside of the vapor chamber 1. For this reason, one method is to check the width and depth of the mainstream groove 41 and the connecting groove 45 from the cross-sectional shape obtained by cutting the completed vapor chamber 1 at a desired position.

[0145] Specifically, first, the vapor chamber 1 was cut into 10 mm square pieces with a wire saw to prepare samples. Next, the sample was embedded in resin while vacuum degassing so that the resin would enter the upper vapor flow passage recess 32, the communication recess 35, and the lower liquid flow passage section 40 (main flow passage groove 41 and communication groove 45). Next, the sample was trimmed with a diamond knife to obtain a desired cross section. At this time, for example, a diamond knife of a microtome (for example, an ultramicrotome manufactured by Leica Microsystems) was used to perform trimming to a portion 40 μm away from the measurement target position. For example, if the pitch of the communication grooves 45 is 200 μm, a portion 40 μm away from the communication groove 45 to be measured can be specified by cutting 160 μm from the communication groove 45 next to the communication groove 45 to be measured. Next, the trimmed cut surface was cut to prepare a cut surface for observation. At this time, a cross-section sample preparation device (e.g., a cross-section polisher manufactured by JOEL) is used to set the protrusion width to 40 μm, the voltage to 5 kV, and the time to 6 hours, and the cut surface is polished by ion beam processing. After that, the cut surface of the obtained sample is observed. At this time, a scanning electron microscope (e.g., a scanning electron microscope manufactured by Carl Zeiss) is used to set the voltage to 5 kV, the working distance to 3 mm, and the observation magnification to 200 times or 500 times, and the cut surface is observed. In this way, the width and depth of the main groove 41 and the connecting groove 45 can be measured. The observation magnification standard during shooting is Polaroid 545. The above-mentioned method is an example, and the device to be used and the measurement conditions can be arbitrarily determined according to the shape and structure of the sample.

[0146] As described above, the width w3 of the communication groove 45 is larger than the width w1 of the main groove 41. As a result, the buffer region Q is a region that is larger in opening than the main groove body 41a. Therefore, in the etching process shown in FIG. 11, the etching liquid enters the buffer region Q more than the main groove body 41a. As a result, the erosion of the buffer region Q by the etching liquid advances, and the depth of the buffer region Q becomes deeper. And, since the portion of the buffer region Q corresponding to the intersection P is connected to the main groove body 41a, the etching liquid enters the portion more easily than the communication groove 45. As a result, the depth h1' of the intersection P can be deeper than the depth h3 of the communication groove 45. In this way, the buffer region Q as shown in FIG. 19 and FIG. 21 is formed.

[0147] Incidentally, a part of the working fluid 2 flowing toward the evaporation portion 31 is drawn into a buffer region Q defined by the intersection portion P and stored therein.

[0148] When dryout occurs in the mainstream groove main body 41a during operation of the vapor chamber 1, the working fluid 2 stored in the buffer region Q moves toward the area where the dryout occurs. More specifically, when dryout occurs in the mainstream groove main body 41a, the working fluid 2 moves from the buffer region Q that is closest to the area where the dryout occurs to the area where the dryout occurs due to the capillary action of the mainstream groove main body 41a. As a result, the area where the dryout occurs is filled with the working fluid 2, and the dryout is resolved.

[0149] Furthermore, when bubbles are generated in the liquid working fluid 2 due to its vapor in the mainstream groove main body 41a, the bubbles are drawn into and held in the buffer region Q on the downstream side (the side of the evaporation section 31). Because the depth of the buffer region Q is greater than the depth h1 of the mainstream groove main body 41a, the bubbles drawn into the buffer region Q are prevented from moving from the buffer region Q to the mainstream groove main body 41a. For this reason, the buffer region Q can capture the bubbles generated in the mainstream groove main body 41a, and the flow of the working fluid 2 to the evaporation section 31 can be prevented from being obstructed by the bubbles.

[0150] Thus, according to this modification, the width w3 of the communication groove 45 is larger than the width w1 of the main groove 41. This can reduce the flow resistance of the working fluid 2 in each communication groove 45. Therefore, the liquid working fluid 2 condensed from the vapor can smoothly enter each main groove 41. That is, the working fluid 2 can smoothly enter not only the main groove 41 communicating with the communication recess 35, but also the main groove 41 not communicating with the communication recess 35, improving the transport function of the condensed liquid working fluid 2. As a result, the transport function of the liquid working fluid 2 can be improved, and the heat transport efficiency can be improved.

[0151] Moreover, according to this modification, the depth h3 of the communication groove 45 is deeper than the depth h1 of the main groove 41. This allows a buffer region Q for storing the working fluid 2 to be formed in each communication groove 45. Therefore, when dryout occurs in the main groove 41, the working fluid 2 stored in the buffer region Q can be moved to the area where the dryout occurs. This makes it possible to eliminate the dryout and to recover the transport function of the working fluid 2 in each main groove 41. Furthermore, when bubbles are generated in the main groove 41, the bubbles can be drawn into the buffer region Q and captured. In this respect as well, the transport function of the working fluid 2 in each main groove 41 can be recovered.

[0152] Furthermore, according to this modification, the depth h1' of the intersection P of the mainstream groove 41 is deeper than the depth h1 of the mainstream groove body 41a. This allows the buffer region Q to extend to the intersection P. This increases the amount of hydraulic fluid 2 stored in the buffer region Q, making it easier to eliminate dryout.

[0153] Furthermore, according to this modification, the depth h1' of the intersection P of the main grooves 41 is deeper than the depth h3 of the communication grooves 45. This allows the depth of the buffer region Q to be deeper on the side closer to the dryout occurrence area of ​​the buffer region Q. This allows the stored working fluid 2 to be smoothly moved to the dryout occurrence area, making it easier to eliminate dryout.

[0154] In the above-mentioned first modified example, the width w3 of the communication groove 45 is larger than the width w1 of the main groove 41, the depth h3 of the communication groove 45 is deeper than the depth h1 of the main groove 41, the depth h1' of the intersection P of the main groove 41 is deeper than the depth h1 of the main groove body 41a, and the depth h1' of the intersection P of the main groove 41 is deeper than the depth h3 of the communication groove 45. That is, in the first modified example, an example having four magnitude relationships for the width and depth has been described. However, this is not limited to this, and as long as at least one of these four magnitude relationships is satisfied, the above-mentioned action and effect corresponding to the magnitude relationship can be achieved. For this reason, all of the four magnitude relationships do not have to be satisfied, and at least one of the magnitude relationships may be satisfied. In this case, the patterning process and the etching process may be performed multiple times as necessary. For example, when the mainstream groove 41 and the communication groove 45 are formed so that the depth h3 of the communication groove 45 is deeper than the depth h1 of the mainstream groove 41, the steps of forming the mainstream groove 41 and the communication groove 45 may be performed separately. More specifically, the mainstream groove 41 is patterned first, and then the resist is removed by etching. Then, the communication groove 45 may be patterned while masking the mainstream groove 41, and then the resist may be removed by etching. Alternatively, the mainstream groove 41 and the communication groove 45 may be patterned and etched simultaneously, and then the resist may be masked from above the mainstream groove body portion 41a without removing the resist, and the communication groove 45 and the intersection portion P may be additionally etched, and then the resist may be removed.

[0155] (Second Modification) In the above-described embodiment, the positions of the protrusions 44 in each protrusion row 43 in the first direction X are the same, and the main grooves 41 and the communication grooves 45 are arranged in a lattice pattern. However, the present invention is not limited to this, and the protrusions 44 may be arranged in a staggered pattern as shown in FIG.

[0156] 22, the communication grooves 45 of adjacent convex rows 43 are arranged offset from each other in the first direction X. In this case, even if the lower metal sheet 10 is depressed inward (toward the wick sheet 30) along the communication grooves 45 due to the pressure of the outside air, the depression can be prevented from crossing the main grooves 41. This makes it possible to ensure the flow path cross-sectional area of ​​the main grooves 41 and prevent the flow of the working fluid 2 from being obstructed. As a result, the transport function of the liquid working fluid 2 can be improved, and the heat transport efficiency can be improved.

[0157] In the embodiment shown in FIG. 22, the main groove 41 and the communication groove 45 intersect in a T-shape. This makes it possible to prevent the communication groove 45 on the other side (for example, the lower side in FIG. 22) from intersecting with the main groove 41 at an intersection where the main groove 41 intersects with the communication groove 45 on one side (for example, the upper side in FIG. 22). This makes it possible to prevent the wall surface 42 (see FIG. 7) of the main groove 41 from being cut out on both sides (upper and lower sides in FIG. 22) at the intersection, and to leave one side of the wall surface 42. Therefore, the capillary action can be imparted to the working fluid 2 in the main groove 41 even at the intersection, and the driving force of the working fluid 2 toward the evaporation section 31 can be suppressed from decreasing at the intersection. As a result, the transport function of the liquid working fluid 2 can be improved, and the heat transport efficiency can be improved.

[0158] (Variation 3) In the above-described embodiment, an example has been described in which the lower surface 30a and the upper surface 30b of the wick sheet 30 are simultaneously etched in the etching step to simultaneously form the upper steam flow path recess 32, the communicating recess 35, and the mainstream groove 41 and the communicating groove 45 of the lower liquid flow path section 40. However, this is not limited to the above, and the lower surface 30a and the upper surface 30b of the wick sheet 30 may be etched separately. Furthermore, for the lower surface 30a of the wick sheet 30, the mainstream groove 41 and the communicating groove 45 of the lower liquid flow path section 40 may be etched separately from the communicating recess 35. In this case, the depth of the mainstream groove 41 and the depth of the communicating groove 45 can be easily made different from the depth of the communicating recess 35.

[0159] (Variation 4) Further, in the above-described embodiment, the communication recess 35 is formed by etching from the lower surface 30a of the wick sheet 30, and the wall surface 36 is formed in a curved shape. However, the present invention is not limited to this, and the communication recess 35 may be formed in any cross-sectional shape as long as it can communicate the upper steam flow path recess 32 and the main groove 41 of the lower liquid flow path section 40. For example, the wall surface 36 of the communication recess 35 may be formed to extend linearly in a direction perpendicular to the lower surface 30a, although not shown. In this case, after the upper steam flow path recess 32 and the lower liquid flow path section 40 are formed in the etching step shown in FIG. 11, the communication recess 35 can be formed by punching from the lower surface 30a. Furthermore, the wall surface 36 of the communication recess 35 may be formed in a trapezoidal shape tapered from the lower surface 30a to the upper surface 30b, although not shown. In this case, after the upper vapor flow path recess 32 and the lower liquid flow path section 40 are formed in the etching step shown in FIG. 11, the communication recess 35 can be formed by irradiating the lower surface 30a with laser light.

[0160] (Variation 5) Furthermore, in the above-described embodiment, a vapor flow path recess (not shown) through which the vapor of the working liquid 2 passes may be formed on the lower surface 30a of the wick sheet 30. In this case, the vapor of the working liquid 2 can be diffused more smoothly, and the heat transport efficiency can be improved.

[0161] (Second embodiment) Next, a wick sheet for a vapor chamber, a vapor chamber, and a method for manufacturing the vapor chamber in the second embodiment of the present invention will be described with reference to FIGS.

[0162] The second embodiment shown in Figures 23 and 24 is different in that the lower heat-sealing layer of the lower metal sheet and the upper heat-sealing layer of the upper metal sheet are heat-sealed, and other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 22. In Figures 23 and 24, the same parts as those of the first embodiment shown in Figures 1 to 22 are denoted by the same reference numerals and detailed description thereof will be omitted.

[0163] 23, in this embodiment, the lower metal sheet 10 has a lower heat seal layer 70 (first heat seal layer) provided on the upper surface 10b outside the wick sheet 30 in a plan view. That is, the lower heat seal layer 70 is disposed on the upper surface 10b at the lower peripheral portion 12 of the lower metal sheet 10, and is formed around the entire periphery of the wick sheet 30 in a plan view, forming a rectangular frame shape.

[0164] The lower heat-sealing layer 70 can be formed by applying a heat-sealing resin material to the upper surface 10b of the lower metal sheet 10 by die coating, roll coating, or the like. As the heat-sealing resin material, taking into consideration the bonding with the lower metal sheet 10 and the sealing of the sealed space 3, for example, high-pressure low-density polyethylene (LDPE), vinyl acetate copolymer (EVA), non-oriented polypropylene (CPP), or the like is preferably used. In order to seal the sealed space 3 and maintain the lower metal sheet 10 in a flat shape, the heat-sealing resin material is preferably applied with a width of 1 mm and a thickness of about 50 μm.

[0165] The upper metal sheet 20 has an upper heat-sealing layer 71 (second heat-sealing layer) provided on the lower surface 20a outside the wick sheet 30 in plan view. That is, the upper heat-sealing layer 71 is disposed on the lower surface 20a at the upper peripheral portion 21 of the upper metal sheet 20, and is formed around the entire periphery of the wick sheet 30 in plan view, forming a rectangular frame shape. The upper heat-sealing layer 71 can be formed on the lower surface 20a of the upper metal sheet 20 by the same method using the same material as the lower heat-sealing layer 70.

[0166] The lower heat-sealing layer 70 and the upper heat-sealing layer 71 are heat-sealed to each other. That is, the lower heat-sealing layer 70 and the upper heat-sealing layer 71 are heat-sealed all around the periphery of the wick sheet 30. In this manner, the sealed space 3 formed by the upper steam flow path recess 32 and the lower liquid flow path portion 40 of the wick sheet 30 is sealed by the lower metal sheet 10, the upper metal sheet 20, and the spacer member 50. In this embodiment, it is preferable to omit the temporary fixing process as shown in FIG. 14 and to perform heat sealing instead of diffusion bonding in the bonding process as shown in FIG. 15. The heat-sealing method is not particularly limited as long as it can seal the sealed space 3.

[0167] Thus, according to this embodiment, the lower heat-sealing layer 70 of the lower metal sheet 10 and the upper heat-sealing layer 71 of the upper metal sheet 20 are heat-sealed. This allows the lower metal sheet 10 and the upper metal sheet 20 to be bonded by heat sealing, which is a relatively simple method, rather than diffusion bonding. This simplifies the manufacturing process of the vapor chamber 1, and allows the vapor chamber 1 to be manufactured easily. This is also advantageous in that it does not require a relatively large-scale diffusion bonding facility to manufacture the vapor chamber 1. Furthermore, when the lower metal sheet 10 and the upper metal sheet 20 are bonded, the temperature rise of each of the metal sheets 10, 20 and the wick sheet 30 can be suppressed. This prevents the materials of each of the metal sheets 10, 20 and the wick sheet 30 from softening or deforming.

[0168] Furthermore, according to this embodiment, the lower metal sheet 10 and the upper metal sheet 20 are heat sealed by the lower heat sealing layer 70 and the upper heat sealing layer 71, which makes it unnecessary to use the spacer member 50 (see FIG. 3, etc.). This allows the mass of the entire vapor chamber 1 to be reduced, resulting in a reduction in weight.

[0169] (Variation 6) In the above-described embodiment, the lower metal sheet 10 and the upper metal sheet 20 are formed in a flat shape. However, the present invention is not limited to this. For example, as shown in FIG. 24, the lower metal sheet 10 and the upper metal sheet 20 may be formed in a flexible film shape. In this case, the thickness of the lower metal sheet 10 and the upper metal sheet 20 is preferably 50 μm to 200 μm, for example.

[0170] In the embodiment shown in Fig. 24, the thickness of the heat-sealable resin material applied to form the lower heat-sealing layer 70 is thinner than that in the embodiment shown in Fig. 23. For example, it can be about 30 µm. As a result, the lower peripheral portion 12 of the lower metal sheet 10 is deformed toward the upper peripheral portion 21 of the upper metal sheet 20. The upper peripheral portion 21 of the upper metal sheet 20 is also deformed toward the lower peripheral portion 12 of the lower metal sheet 10, and the lower peripheral portion and the upper peripheral portion are heat-sealed via the lower heat-sealing layer and the upper heat-sealing layer.

[0171] 24, the thickness of the lower metal sheet 10 and the thickness of the upper metal sheet 20 can be reduced, so that the thickness of the entire vapor chamber 1 can be reduced. In addition, the weight can be further reduced.

[0172] (Third embodiment) Next, a wick sheet for a vapor chamber, a vapor chamber, and a method for manufacturing the vapor chamber according to a third embodiment of the present invention will be described with reference to FIGS.

[0173] The third embodiment shown in Figures 25 to 33 is different in that the steam flow path portion of the wick sheet extends from the second surface to the first surface, and other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 22. In Figures 25 to 33, the same parts as those of the first embodiment shown in Figures 1 to 22 are denoted by the same reference numerals and detailed description thereof will be omitted.

[0174] In this embodiment, as shown in Figs. 25 to 28, the vapor chamber 1 includes a lower metal sheet 10, an upper metal sheet 20, and a wick sheet 30. The spacer member 50 shown in Fig. 3 and the like is not provided between the lower metal sheet 10 and the upper metal sheet 20. Therefore, the lower surface 30a of the wick sheet 30 is diffusion bonded to the upper surface 10b of the lower metal sheet 10, and the upper surface 30b is diffusion bonded to the lower surface 20a of the upper metal sheet 20. The sealed space 3 is formed by a first steam passage 81 and a second steam passage 82 (a lower steam passage recess 85 and an upper steam passage recess 86 described later) of the steam passage section 80, and a main stream groove 41 and a communication groove 45 of the lower liquid passage section 40.

[0175] The vapor flow path portion 80 of the wick sheet 30 extends from the upper surface 30b to the lower surface 30a of the wick sheet 30, and is formed so as to penetrate the wick sheet 30. This vapor flow path portion 80 is configured so that the vapor of the working fluid 2 can pass through it, and is defined inside a frame portion 83 described later.

[0176] The wick sheet 30 according to the present embodiment has a frame portion 83 formed in a rectangular frame shape in a plan view, and a land portion 84 provided within the frame portion 83. The frame portion 83 and the land portion 84 are not etched in the etching step shown in FIG. 11, and are portions where the material of the wick sheet 30 remains.

[0177] A plurality of land portions 84 are arranged in the steam flow passage portion 80, and divide the steam flow passage portion 80 into a first steam passage 81 and a plurality of second steam passages 82. The steam flow passage portion 80 is formed around the land portion 84 in a plan view. The first steam passage 81 is formed between the land portion 84 and the frame portion 83. The first steam passage 81 is formed inside the frame portion 83 and continuously outside the land portion 84. The planar shape of the first steam passage 81 is a rectangular frame shape. The second steam passage 82 is formed between the adjacent land portions 84. The planar shape of the second steam passage 82 is an elongated rectangular shape. The first steam passage 81 and the second steam passage 82 constitute the steam flow passage portion 80.

[0178] 26, the steam flow path section 80 is composed of a lower steam flow path recess 85 provided in the lower surface 30a and an upper steam flow path recess 86 provided in the upper surface 30b. The lower steam flow path recess 85 and the upper steam flow path recess 86 are in communication with each other, so that the steam flow path section 80 extends from the upper surface 30b to the lower surface 30a.

[0179] The lower steam flow passage recess 85 constitutes a part of the sealed space 3, and is mainly configured so that the steam of the working fluid 2 generated in the evaporator 31 passes through it. The lower steam flow passage recess 85 is formed in a concave shape on the lower surface 30a of the wick sheet 30 by etching the lower surface 30a in an etching step shown in FIG. 11. As a result, the lower steam flow passage recess 85 has a wall surface 87 formed in a curved shape as shown in FIG. 26. The wall surface 87 defines the lower steam flow passage recess 85, and is curved in a shape that bulges toward the upper surface 30b. The wall surface 87 has a plurality of curved concave portions, and each concave portion forms a part (lower half) of the first steam passage 81 or a part (lower half) of the second steam passage 82.

[0180] The upper steam flow passage recess 86 constitutes a part of the sealed space 3, and is mainly configured so that the steam of the working fluid 2 generated in the evaporator 31 passes through it. The upper steam flow passage recess 86 is formed in a concave shape on the upper surface 30b of the wick sheet 30 by etching the upper surface 30b in an etching process shown in FIG. 11. As a result, the upper steam flow passage recess 86 has a wall surface 88 formed in a curved shape as shown in FIG. 26. The wall surface 88 defines the upper steam flow passage recess 86, and is curved in a shape that bulges toward the lower surface 30a. The wall surface 88 has a plurality of curved concave portions, and each concave portion forms a part (upper half) of the first steam passage 81 or a part (upper half) of the second steam passage 82.

[0181] A wall surface 87 of the lower steam passage recess 85 and a wall surface 88 of the upper steam passage recess 86 are connected to each other to form a through-portion 89. The wall surface 87 and the wall surface 88 are curved toward the through-portion 89. As a result, the lower steam passage recess 85 and the upper steam passage recess 86 are connected to each other. In this embodiment, the planar shape of the through-portion 89 in the first steam passage 81 is a rectangular frame shape similar to the first steam passage 81, and the planar shape of the through-portion 89 in the second steam passage 82 is an elongated rectangular shape similar to the second steam passage 82. The through-portion 89 is defined by a ridge line formed by joining the wall surface 87 of the lower steam passage recess 85 and the wall surface 88 of the upper steam passage recess 86 and projecting inward. The planar area of ​​the steam passage portion 80 is minimum at this through-portion 89. The width dimension w6 of such a through-portion 89 is, for example, 400 μm to 1600 μm. The position of the through-hole 89 in the thickness direction of the wick sheet 30 (the vertical direction in FIG. 26) may be an intermediate position between the lower surface 30a and the upper surface 30b, or may be a position shifted downward or upward from the intermediate position, and is arbitrary as long as the lower steam flow path recess 85 and the upper steam flow path recess 86 communicate with each other. In the present embodiment, the cross-sectional shapes of the first steam passage 81 and the second steam passage 82 are formed to include the through-hole 89 defined by a ridge line formed to protrude inward, but are not limited to this. For example, the cross-sectional shapes of the first steam passage 81 and the second steam passage 82 may be trapezoidal or rectangular, or may be barrel-shaped.

[0182] The above-mentioned frame portion 83 has a frame lower surface 83a (first frame surface) constituting the lower surface 30a of the wick sheet 30, and a frame upper surface 83b (second frame surface) constituting the upper surface 30b. That is, the frame lower surface 83a is located on the same plane as the lower surface 30a, and the frame upper surface 83b is located on the same plane as the upper surface 30b. The frame lower surface 83a abuts against the upper surface 10b of the lower metal sheet 10 and is diffusion-bonded thereto. The frame upper surface 83b abuts against the lower surface 20a of the upper metal sheet 20 and is diffusion-bonded thereto.

[0183] The land portion 84 described above has a land lower surface 84a (first land surface) constituting the lower surface 30a of the wick sheet 30, and a land upper surface 84b (second land surface) constituting the upper surface 30b. That is, the land lower surface 84a is located on the same plane as the lower surface 30a, and the land upper surface 84b is located on the same plane as the upper surface 30b. The land lower surface 84a abuts on the upper surface 10b of the lower metal sheet 10 and is diffusion-bonded thereto. The land upper surface 84b abuts on the lower surface 20a of the upper metal sheet 20 and is diffusion-bonded thereto. In this way, the mechanical strength of the vapor chamber 1 is improved when the sealed space 3 is decompressed. The wall surface 87 of the lower steam flow passage recess 85 and the wall surface 88 of the upper steam flow passage recess 86 described above constitute the side walls of the land portion 84.

[0184] In addition, the lower metal sheet 10 and the wick sheet 30 (the frame portion 83 and the land portion 84) may be joined by other methods such as brazing instead of diffusion bonding as long as they can be permanently joined. The same applies to the wick sheet 30 and the upper metal sheet 20.

[0185] In this embodiment, the land portion 84 extends in an elongated shape along the first direction X in a plan view, and the planar shape of the land portion 84 is an elongated rectangular shape. The lands 84 are arranged parallel to each other at equal intervals in the second direction Y. In this manner, the vapor of the working fluid 2 flows around each land portion 84, and the vapor is transported toward the peripheral portion of the wick sheet 30, suppressing the flow of the vapor from being impeded. The width w7 of the land portion 84 is, for example, 100 μm to 1500 μm. Here, the width w7 of the land portion 84 is the dimension of the land portion 84 in the second direction Y, and means the dimension at the position where the through portion 89 exists in the thickness direction of the wick sheet 30.

[0186] As shown in Figs. 27 to 29, a first support portion 91 that supports the land portion 84 on the frame body portion 83 is provided in the steam flow path portion 80. In this embodiment, each land portion 84 is supported on the frame body portion 83 by the first support portion 91 provided on both sides of the land portion 84 in the first direction X. In addition, a plurality of first support portions 91 are also provided on both sides of the land portion 84 in the second direction Y. The land portions 84 arranged on both sides in the second direction Y are supported on the frame body portion 83 by these first support portions 91. Note that Figs. 27 and 28 show an example in which each land portion 84 is supported on the frame body portion 83 by the corresponding first support portion 91 in the first direction X, but this is not limited to this. For example, a plurality of land portions 84 may be supported on the frame body portion 83 by one first support portion 91, that is, several first support portions 91 adjacent to each other shown in Fig. 27 may be formed integrally and continuously. Furthermore, all of the land portions 84 may be supported by the frame portion 83 by one first support portion 91 on both sides in the first direction X. In this case, the portions of the lower frame body fluid flow path portion 97 (portions along the second direction Y, the right and left portions in FIGS. 27 and 28) provided on both sides of the land portions 84 in the first direction X, which will be described later, may not be provided. However, such portions may be provided. In this case, the portions of the lower frame body fluid flow path portion 97 provided on both sides of the land portions 84 in the second direction Y (portions along the first direction X, the upper and lower portions in FIGS. 27 and 28) can be communicated, and the liquid working fluid 2 can be caused to flow between both portions.

[0187] As shown in FIG. 29, the first support portion 91 is provided on the lower surface 30a side of the wick sheet 30, and an upper steam flow path recess 86 is provided on the upper surface 30b side of the first support portion 91.

[0188] The first support portion 91 is formed continuously on the corresponding land portion 84 and frame portion 83. That is, the first support portion 91 is a portion where the material of the wick sheet 30 remains without being etched in the etching step shown in FIG. 11. For example, the first support portion 91 can be formed by performing an etching step so as to form the upper steam flow passage recess 86 while not forming the lower steam flow passage recess 85. In this case, as shown in FIG. 11, the resist material is left in the second resist opening 63 for forming the lower steam flow passage recess 85, and the lower resist film 60 is patterned so as to divide the second resist opening 63. As a result, the portion of the lower surface Ma of the metal material sheet M where the resist material remains in the second resist opening 63 is not etched from the lower surface Ma, and the material of the metal material sheet M remains. On the other hand, by forming the third resist opening 64 in the portion of the upper resist film 61 corresponding to the first support portion 91, the portion of the upper surface Mb of the metal material sheet M corresponding to the first support portion 91 is etched to form the upper steam flow passage recess 86. In this manner, as shown in FIGS. 27 to 29, the first support portion 91 can be formed while the upper steam flow passage recess 86 is being continuously formed.

[0189] In addition, second support parts 92 that support adjacent land parts 84 are provided in the steam flow path part 80. In this embodiment, the land parts 84 are arranged at a distance in the second direction Y as described above, and a plurality of second support parts 92 are provided between adjacent land parts 84. Each second support part 92 is arranged at the same position as the corresponding first support part 91 in the first direction X. However, the arrangement of each second support part 92 is not limited to this. For example, each second support part 92 may be arranged at a position different from the first support part 91 in the first direction X, for example, may be arranged in a staggered manner. In addition, although an example in which each land part 84 is supported by a plurality of second support parts 92 is shown in FIG. 27 and FIG. 28, this is not limiting, and each land part 84 may be supported by one second support part 92.

[0190] As shown in FIG. 29, the second support portion 92 is provided on the lower surface 30a side of the wick sheet 30, and an upper steam flow path recess 86 is provided on the upper surface 30b side of the second support portion 92.

[0191] The second support portion 92 is formed continuously on the corresponding land portion 84. The second support portion 92 is also a portion that is not etched in the etching step shown in Fig. 11 and where the material of the wick sheet 30 remains. The second support portion 92 can be formed in the same manner as the first support portion 91.

[0192] In the embodiment of FIG. 27 to FIG. 29, the first support portion 91 and the second support portion 92 are formed so as to be aligned with the first direction X or the second direction Y. However, the shape of the support portions 91 and 92 does not have to be aligned with the first direction X or the second direction Y, and is arbitrary. The height h2 (the vertical dimension in FIG. 29) of the first support portion 91 and the second support portion 92 is arbitrary, and may be smaller than half the height of the wick sheet 30, for example. In this case, the first support portion 91 and the second support portion 92 can suppress the steam flow of the working fluid 2 from being hindered (the flow path resistance is increased). Here, the height h2 of the first support portion 91 and the second support portion 92 is the minimum height of each support portion 91, 92, and corresponds to the distance between the point of the corresponding upper steam flow path recess 86 closest to the lower surface 30a and the lower surface 30a.

[0193] 25, lower alignment holes 15 are provided at the four corners of the lower metal sheet 10, and upper alignment holes 24 are provided at the four corners of the upper metal sheet 20. Wick sheet alignment holes 93 are provided at the four corners of the wick sheet 30. Corresponding alignment holes 15, 24, 93 are aligned so as to overlap with each other in the temporary fixing process shown in FIG. 14, allowing the lower metal sheet 10, upper metal sheet 20, and wick sheet 30 to be positioned.

[0194] As shown in FIG. 25, the vapor chamber 1 further includes an injection section 4 at one end of a pair of ends in the first direction X for injecting the working liquid 2 into the sealed space 3. The injection section 4 has a lower injection protrusion 16 protruding from an end face of the lower metal sheet 10, an upper injection protrusion 25 protruding from an end face of the upper metal sheet 20, and a wick sheet protrusion 94 protruding from an end face of the wick sheet 30. An injection flow path 95 is formed in the wick sheet protrusion 94. The injection flow path 95 extends from the lower surface 30a to the upper surface 30b of the wick sheet 30, penetrating the wick sheet 30. The injection flow path 95 is also connected to the lower liquid flow path section 40 and the vapor flow path section 80, which will be described later, and the working liquid 2 is injected into the sealed space 3 through the injection flow path 95. The upper surface of the lower injection protrusion 16 and the lower surface of the upper injection protrusion 25 are formed flat. In this embodiment, the injection part 4 is provided at one end of a pair of ends in the first direction X of the vapor chamber 1, but the present invention is not limited to this. The injection flow path 95 does not have to penetrate the wick sheet 30. In this case, the injection flow path 95 communicating with the lower liquid flow path part 40 and the vapor flow path part 80 can be formed by etching only from one of the lower surface 30a and the upper surface 30b of the wick sheet 30. Furthermore, the injection part 4 may be constituted by the injection hole 22 as in the first embodiment.

[0195] As shown in Figs. 26 and 28, a lower liquid flow path section 40 (liquid flow path section) through which the liquid working fluid 2 passes is provided on the lower surface 30a of the wick sheet 30. In this embodiment, the lower liquid flow path section 40 includes a lower land liquid flow path section 96 (first land liquid flow path section) provided on the land lower surface 84a of each land section 84, and a lower frame body fluid flow path section 97 (first frame body fluid flow path section) provided on the frame lower surface 83a of the frame section 83. The lower land liquid flow path section 96 and the lower frame body fluid flow path section 97 form a part of the above-mentioned sealed space 3. The lower land liquid flow path section 96 communicates with the first steam passage 81 and the second steam passage 82 of the steam flow path section 80, and the lower frame body fluid flow path section 97 communicates with the first steam passage 81.

[0196] As shown in FIG. 30, the lower land liquid flow path section 96 has a plurality of main grooves 41 extending in the first direction X and a communication groove 45 that communicates adjacent main grooves 41, similar to the lower liquid flow path section 40 in the first embodiment. A convex portion row 43 is provided between adjacent main grooves 41. Each convex portion row 43 includes a plurality of convex portions 44 arranged in the first direction X. The convex portions 44 may be arranged in a staggered manner, similar to the embodiment shown in FIG. 22. However, the plurality of main grooves 41 and the plurality of communication grooves 45 may be arranged in a lattice shape, similar to the embodiment shown in FIG. 6. When the width w3 of the communication groove 45 is larger than the width w1 of the main groove 41, as shown in FIG. 19, the flow path resistance of the working fluid 2 in each communication groove 45 can be reduced. Therefore, the working fluid 2 in liquid form condensed from the vapor can be smoothly introduced into each main groove 41. In other words, the condensed liquid working fluid 2 can be smoothly introduced not only into the main grooves 41 closer to the steam passages 81, 82, but also into the main grooves 41 farther from the steam passages 81, 82, thereby improving the transport function of the condensed liquid working fluid 2.

[0197] The lower frame body fluid flow path section 97 can be configured in the same manner as the lower land fluid flow path section 96. Therefore, detailed description will be omitted here. In the lower frame body fluid flow path section 97, in the portions on both sides of the land portion 84 in the first direction X, the flow of the liquid working fluid 2 along the second direction Y becomes a flow toward the evaporation section 31, so in these portions, the grooves extending in the second direction Y will be described as main grooves 41 and the grooves extending in the first direction X as communication grooves 45.

[0198] The steam flow passage section 80 communicates with the communication groove 45 of the lower liquid flow passage section 40. More specifically, the lower steam flow passage recess 85 of the first steam passage 81 communicates with the communication groove 45 of the lower land liquid flow passage section 96 and also communicates with the communication groove 45 of the lower frame body liquid flow passage section 97. This allows the liquid working fluid 2 in the lower steam flow passage recess 85 of the first steam passage 81 to easily enter the multiple main grooves 41 of the lower land liquid flow passage section 96 and the lower frame body liquid flow passage section 97. Similarly, the lower steam flow passage recess 85 of the second steam passage 82 communicates with the communication groove 45 of the lower land liquid flow passage section 96, allowing the liquid working fluid 2 in the lower steam flow passage recess 85 of the second steam passage 82 to easily enter the multiple main grooves 41 of the lower land liquid flow passage section 96.

[0199] During operation of the vapor chamber 1 according to this embodiment, most of the vapor of the working liquid 2 generated by receiving heat from the device D diffuses in the lower vapor flow passage recess 85 and the upper vapor flow passage recess 86 of the first vapor passage 81 and the second vapor passage 82 constituting the sealed space 3 (see the solid arrows in Figs. 27 and 28). The vapor in each of the vapor flow passage recesses 85, 86 leaves the evaporation section 31, and most of the vapor is transported to the peripheral portion of the wick sheet 30, which has a relatively low temperature. The vapor diffused in the upper vapor flow passage recess 86 is cooled by dissipating heat mainly to the upper metal sheet 20, and the vapor diffused in the lower vapor flow passage recess 85 is cooled by dissipating heat mainly to the wick sheet 30. The heat received by the upper metal sheet 20 from the vapor is transferred to the outside air via the housing member Ha (see Fig. 3). The heat received by the wick sheet 30 from the vapor is transferred to the outside air via the upper metal sheet 20 and the housing member Ha.

[0200] The steam that has released heat is condensed, and the liquid working fluid 2 adheres to the wall surface 87 of the lower steam flow path recess 85 and the wall surface 88 of the upper steam flow path recess 86, as well as to the upper surface 10b of the lower metal sheet 10 and the lower surface 20a of the upper metal sheet 20. Since the working fluid 2 continues to evaporate in the evaporation section 31, the working fluid 2 in the lower land liquid flow path section 96 and the lower frame body fluid flow path section 97 of the lower liquid flow path section 40 other than the evaporation section 31 is transported toward the evaporation section 31 (see the dashed arrows in FIG. 28). As a result, the liquid working fluid 2 adhered to the wall surface 87 of the lower steam flow path recess 85 and the upper surface 10b of the lower metal sheet 10 moves to the lower land liquid flow path section 96 or the lower frame body fluid flow path section 97. The liquid working fluid 2 adhering to the wall surface 88 of the upper steam flow path recess 86 and the lower surface 20a of the upper metal sheet 20 moves through the wall surface 87 of the lower steam flow path recess 85 to the communication groove 45 of the lower land liquid flow path section 96 or the communication groove 45 of the lower frame body fluid flow path section 97. Here, the lower steam flow path recess 85 and the communication groove 45 are provided on the lower surface 30a of the wick sheet 30 and are in contact with the upper surface 10b of the lower metal sheet 10. This allows the working fluid 2 adhering to the upper surface 10b to be smoothly drawn into the communication groove 45 by the capillary force of the communication groove 45. This makes it possible to prevent the liquid working fluid 2 from accumulating in the lower steam flow path recess 85. In the lower land liquid flow path section 96 and the lower frame body fluid flow path section 97, the liquid working fluid 2 that has entered the communication groove 45 enters the main stream groove 41, and the main stream groove 41 and each communication groove 45 are filled with the liquid working fluid 2. Therefore, the filled working fluid 2 obtains a propulsive force toward the evaporation section 31 due to the capillary action of each main groove 41 and each communication groove 45 , and is smoothly transported toward the evaporation section 31 .

[0201] The working fluid 2 that has reached the evaporation section 31 receives heat from the device D again via the heat receiving section 11 of the lower metal sheet 10 and evaporates. The vapor of the working fluid 2 that has evaporated in the lower land liquid flow path section 96 and the lower frame liquid flow path section 97 passes through the communication groove 45 and moves to the lower vapor flow path recess 85, which has a large flow path cross-sectional area, and diffuses, and a part of the vapor moves to the upper vapor flow path recess 86 and diffuses. In this way, the working fluid 2 circulates within the sealed space 3 while repeatedly changing phases, i.e., evaporating and condensing, and transports and releases heat from the device D. As a result, the device D is cooled.

[0202] Thus, according to this embodiment, the vapor flow path section 80 through which the vapor of the working liquid 2 passes extends from the upper surface 30b to the lower surface 30a of the wick sheet 30. This allows the liquid working liquid 2 condensed in the vapor flow path section 80 to move smoothly to the lower liquid flow path section 40 provided on the lower surface 30a. This allows the liquid working liquid 2 to be smoothly transported to the evaporation section 31. In addition, the flow path area of ​​the vapor flow path section 80 can be increased. This allows the vapor of the working liquid 2 evaporated in the evaporation section 31 to be smoothly diffused to the peripheral portion of the wick sheet 30.

[0203] Furthermore, according to this embodiment, the lower steam flow path recess 85 of the steam flow path section 80 contacts and communicates with the communication grooves 45 of the lower land liquid flow path section 96 and the lower frame body liquid flow path section 97. This allows the liquid working fluid 2 in the lower steam flow path recess 85 to smoothly flow into the multiple main flow grooves 41. This allows the liquid working fluid 2 to be transported by the evaporation section 31 even more smoothly.

[0204] Furthermore, according to this embodiment, a land portion 84 is provided in the vapor flow path portion 80 defined inside the frame portion 83 of the wick sheet 30. This makes it possible to prevent the lower metal sheet 10 and the upper metal sheet 20 from being deformed by the pressure of the outside air when the sealed space 3 is depressurized, thereby improving the mechanical strength of the vapor chamber 1.

[0205] Furthermore, according to this embodiment, a lower land liquid flow path section 96 of the lower liquid flow path section 40 is provided on the land underside 84a of the land section 84 of the wick sheet 30, and the steam flow path section 80 is formed around this lower land liquid flow path section 96. This allows the liquid working fluid 2 condensed in the first steam passage 81 and the second steam passage 82 of the steam flow path section 80 to be smoothly moved to the lower land liquid flow path section 96, and allows the vapor of the working fluid 2 evaporated in the lower land liquid flow path section 96 to be smoothly diffused into the first steam passage 81 and the second steam passage 82 of the steam flow path section 80.

[0206] Further, according to this embodiment, the first support portion 91 that supports the land portion 84 on the frame portion 83 is provided in the vapor flow path portion 80. This allows the land portion 84 to be supported on the frame portion 83, and the land portion 84 and the frame portion 83 to be integrated. This prevents the handleability of the wick sheet 30 from decreasing during manufacturing, and allows the vapor chamber 1 to be easily manufactured. In particular, according to this embodiment, the first support portion 91 is provided on the lower surface 30a side of the wick sheet 30. This allows the upper steam flow path recess 86 to be formed on the upper surface 30b side of the first support portion 91, and prevents the first steam passage 81 from being divided. This allows the decrease in the diffusibility of the vapor of the working fluid 2 to be suppressed.

[0207] Further, according to this embodiment, the second support portion 92 that supports the adjacent land portions 84 is provided in the vapor flow passage portion 80. This allows the adjacent land portions 84 to be supported by each other, and the multiple land portions 84 can be integrated, and these land portions 84 and the frame portion 83 can be integrated. Therefore, it is possible to prevent the handleability of the wick sheet 30 from decreasing during manufacturing, and the vapor chamber 1 can be easily manufactured. In particular, according to this embodiment, the second support portion 92 is provided on the side of the lower surface 10a of the wick sheet 30. This allows the upper steam flow passage recess 86 to be formed on the side of the upper surface 30b of the second support portion 92, and the second steam passage 82 can be prevented from being divided. Therefore, it is possible to suppress a decrease in the diffusibility of the vapor of the working fluid 2.

[0208] Furthermore, according to this embodiment, a lower frame body fluid flow path section 97 of the lower liquid flow path section 40 is provided on the frame lower surface 83a of the frame section 83 of the wick sheet 30. This allows the liquid working fluid 2 condensed in the first steam passage 81 of the steam flow path section 80 to be smoothly moved to the lower frame body fluid flow path section 97, and allows the vapor of the working fluid 2 evaporated in the lower frame body fluid flow path section 97 to be smoothly diffused into the first steam passage 81 of the steam flow path section 80.

[0209] Furthermore, according to this embodiment, the lower metal sheet 10 and the wick sheet 30 are diffusion bonded together. This allows the lower metal sheet 10 and the wick sheet 30 to be diffusion bonded together over a wide range, thereby improving the bonding strength. Also, the upper metal sheet 20 and the wick sheet 30 are diffusion bonded together. This allows the upper metal sheet 20 and the wick sheet 30 to be diffusion bonded together over a wide range, thereby improving the bonding strength.

[0210] (Variation 7) In the above-described embodiment, an example in which the lower liquid flow path section 40 is provided on the lower surface 30a of the wick sheet 30 has been described. However, this is not limited thereto, and for example, as shown in Figs. 31 to 33, the liquid flow path section may be provided not only on the lower surface 30a of the wick sheet 30 but also on the upper surface 30b. Fig. 31 shows an example in which the lower liquid flow path section 40 is provided on the lower surface 30a of the wick sheet 30, and the upper liquid flow path section 98 is provided on the upper surface 30b. In the example shown in Fig. 31, the upper liquid flow path section 98 includes an upper land liquid flow path section 99 (second land liquid flow path section) provided on the land upper surface 84b of each land section 84, and an upper frame body fluid flow path section 100 (second frame body fluid flow path section) provided on the frame upper surface 83b of the frame section 83. The upper land liquid flow path section 99 and the upper frame body fluid flow path section 100 constitute a part of the sealed space 3 described above. The upper land liquid flow path section 99 communicates with the upper steam flow path recesses 86 of the first steam passage 81 and the second steam passage 82 of the steam flow path section 80, and the upper frame body fluid flow path section 100 communicates with the upper steam flow path recess 86 of the first steam passage 81. The upper land liquid flow path section 99 can be configured in the same manner as the lower land liquid flow path section 96, and the upper frame body fluid flow path section 100 can be configured in the same manner as the lower frame body fluid flow path section 97.

[0211] 31, an upper liquid flow path portion 98 is provided on the upper surface 30b of the wick sheet 30. This makes it possible to increase the number of flow paths for transporting the liquid working fluid 2 to the evaporation portion 31, thereby improving the transport efficiency of the liquid working fluid 2 to the evaporation portion 31. As a result, the heat transport efficiency of the vapor chamber 1 can be improved.

[0212] According to the embodiment shown in FIG. 31, an upper land liquid flow path section 99 is provided on the land upper surface 84b of the land section 84 of the wick sheet 30. This allows the liquid working fluid 2 condensed in the first steam passage 81 and the second steam passage 82 of the steam flow path section 80 to move smoothly to the upper land liquid flow path section 99, and allows the vapor of the working fluid 2 evaporated in the upper land liquid flow path section 99 to be smoothly diffused into the first steam passage 81 and the second steam passage 82 of the vapor flow path section 80. Also, an upper frame body fluid flow path section 100 is provided on the frame upper surface 83b of the frame section 83 of the wick sheet 30. This allows the liquid working fluid 2 condensed in the first steam passage 81 of the vapor flow path section 80 to move smoothly to the upper frame body fluid flow path section 100, and allows the vapor of the working fluid 2 evaporated in the upper frame body fluid flow path section 100 to be smoothly diffused into the first steam passage 81 of the vapor flow path section 80.

[0213] 32, the main grooves 41 provided on the lower surface 30a of the wick sheet 30 and the main grooves 41 provided on the upper surface 30b may overlap each other in a plan view. In this case, the structure of the wick sheet 30 can be unified between the lower surface 30a and the upper surface 30b.

[0214] On the other hand, as shown in FIG. 33, the main groove 41 provided on the lower surface 30a of the wick sheet 30 and the main groove 41 provided on the upper surface 30b may not overlap at least partially in a plan view. That is, the main groove 41 on the lower surface 30a may be shifted from the main groove 41 on the upper surface 30b. In the example shown in FIG. 33, the main groove 41 provided on the upper surface 30b is disposed between a pair of adjacent main grooves 41 provided on the lower surface 30a in a plan view. In this case, the main groove 41 on the lower surface 30a and the main groove 41 on the upper surface 30b can be prevented from communicating with each other. In addition, the communication groove 45 on the lower surface 30a and the communication groove 45 on the upper surface 30b can be prevented from overlapping in a plan view, and these communication grooves 45 can be prevented from communicating with each other. This is effective, for example, when the depth of the communication groove 45 is deeper than the depth of the main groove 41.

[0215] (Variation 8) In the above-described embodiment, an example has been described in which the spacer member 50 is not provided between the lower metal sheet 10 and the upper metal sheet 20. However, the present invention is not limited to this, and the spacer member 50 may be provided in the same manner as in the first embodiment. In this case, the lower peripheral portion 12 of the lower metal sheet 10 may be diffusion bonded to the spacer member 50, and the upper peripheral portion 21 of the upper metal sheet 20 may be diffusion bonded to the spacer member 50. The lower metal sheet 10 and the wick sheet 30 may not be bonded to each other, and the upper metal sheet 20 and the wick sheet 30 may not be bonded to each other.

[0216] (Variation 9) In the above-described embodiment, an example has been described in which the lower metal sheet 10 and the wick sheet 30 are diffusion bonded, and the upper metal sheet 20 and the wick sheet 30 are diffusion bonded. However, the present invention is not limited to this, and similarly to the second embodiment, a lower heat-sealing layer 70 may be provided on the lower metal sheet 10, an upper heat-sealing layer 71 may be provided on the upper metal sheet 20, and the lower heat-sealing layer 70 and the upper heat-sealing layer 71 may be heat-sealed.

[0217] (Variation 10) In the above-described embodiment, the lower metal sheet 10 and the upper metal sheet 20 are formed in a flat shape. However, the present invention is not limited to this, and the lower metal sheet 10 and the upper metal sheet 20 may be formed in a flexible film shape, for example, as in the embodiment shown in FIG.

[0218] (Fourth embodiment) Next, a wick sheet for a vapor chamber, a vapor chamber, and a method for manufacturing the vapor chamber in the fourth embodiment of the present invention will be described with reference to FIG.

[0219] The fourth embodiment shown in Fig. 34 is different from the third embodiment shown in Fig. 25 to Fig. 33 in that the lower metal sheet has a lower main body sheet and a lower reinforcing sheet, and the upper metal sheet has an upper main body sheet and an upper reinforcing sheet, and the other configurations are substantially the same as those of the third embodiment shown in Fig. 25 to Fig. 33. In Fig. 34, the same parts as those of the third embodiment shown in Fig. 25 to Fig. 33 are denoted by the same reference numerals and detailed description thereof will be omitted.

[0220] In this embodiment, as shown in Fig. 34, the lower metal sheet 10 of the vapor chamber 1 may have a lower main body sheet 111 (first main body sheet) provided on the wick sheet 30 side, and a lower reinforcing sheet 112 (first reinforcing sheet) provided on the opposite side of the wick sheet 30 side (lower side in Fig. 34) with respect to the lower main body sheet 111. The lower reinforcing sheet 112 has a higher mechanical strength (e.g., tensile strength) than the lower main body sheet 111. The lower main body sheet 111 is diffusion bonded to the wick sheet 30.

[0221] The lower body sheet 111 may be made of the same material as the wick sheet 30. When the lower body sheet 111 and the wick sheet 30 are made of copper, the lower reinforcing sheet 112 may be made of, for example, stainless steel or nickel. Such a lower metal sheet 10 may be made of a so-called clad material in which different types of metal sheets are combined. One of the lower body sheet 111 and the lower reinforcing sheet 112 may be made of metal foil, and the other sheet may be made by plating the metal foil. The lower body sheet 111 and the lower reinforcing sheet 112 may be bonded together with an adhesive or the like, or may be joined by any other method. The thickness of the lower body sheet 111 may be smaller or larger than the thickness of the lower reinforcing sheet 112, and the thickness of the lower body sheet 111 and the thickness of the lower reinforcing sheet 112 may be equal.

[0222] Like the lower metal sheet 10, the upper metal sheet 20 may have an upper main body sheet 121 (second main body sheet) provided on the wick sheet 30 side, and an upper reinforcing sheet 122 (second reinforcing sheet) provided on the opposite side of the upper main body sheet 121 to the wick sheet 30 side (upper side in FIG. 34). The upper reinforcing sheet 122 has higher mechanical strength (e.g., tensile strength, 0.2% proof stress, upper yield point, etc.) than the upper main body sheet 121. The lower main body sheet 111 is diffusion bonded to the wick sheet 30.

[0223] Thus, according to this embodiment, the lower metal sheet 10 has the lower main body sheet 111 provided on the side of the wick sheet 30 and the lower reinforcing sheet 112 provided on the opposite side of the wick sheet 30 with respect to the lower main body sheet 111, and the lower reinforcing sheet 112 has a higher mechanical strength than the lower main body sheet 111. This makes it possible to reinforce the lower metal sheet 10. For example, when the sealed space 3 is depressurized, it is possible to prevent the lower metal sheet 10 from being deformed so as to be recessed by the pressure of the outside air, and the mechanical strength of the vapor chamber 1 can be improved. In addition, when pure water is used as the working liquid 2, the working liquid 2 may expand due to freezing, but even in this case, it is possible to prevent the lower metal sheet 10 from being deformed.

[0224] Furthermore, according to this embodiment, the mechanical strength of the lower metal sheet 10 can be improved, so the thickness of the lower metal sheet 10 can be reduced. This reduction in thickness can be allocated to the thickness of the wick sheet 30, so that the wick sheet 30 can be made thicker. In this case, the flow path area of ​​the vapor flow path section can be increased, and the vapor of the working fluid 2 evaporated in the evaporation section 31 can be smoothly diffused to the peripheral edge of the wick sheet 30.

[0225] Further, according to this embodiment, the upper metal sheet 20 has an upper main body sheet 121 provided on the side of the wick sheet 30 and an upper reinforcing sheet 122 provided on the opposite side of the wick sheet 30 with respect to the upper main body sheet 121, and the upper reinforcing sheet 122 has a higher mechanical strength than the upper main body sheet 121. This makes it possible to reinforce the upper metal sheet 20. For example, when the sealed space 3 is depressurized, it is possible to prevent the upper metal sheet 20 from being deformed so as to be recessed by the pressure of the outside air, and the mechanical strength of the vapor chamber 1 can be improved. Furthermore, when pure water is used as the working liquid 2, the working liquid 2 may expand due to freezing, but even in this case, it is possible to prevent the upper metal sheet 20 from being deformed.

[0226] The present invention is not limited to the above-mentioned embodiments and modifications, and can be embodied by modifying the components without departing from the gist of the invention in the implementation stage. Various inventions can be formed by appropriate combinations of the components disclosed in the above-mentioned embodiments and modifications (including combinations of the modifications). Some components may be deleted from all the components shown in the embodiments and modifications. In the above-mentioned embodiments and modifications, the configuration of the lower metal sheet 10 and the configuration of the upper metal sheet 20 may be interchanged. [Explanation of symbols]

[0227] 1 Vapor chamber 2. Hydraulic Fluid 3 Sealed space 10 Lower metal sheet 10b Top side 12 Lower periphery 20 Upper metal sheet 20a Bottom side 21 Upper periphery 30 Wick Sheet 30a Bottom side 30b Top surface 32 Upper steam passage recess 33 Wall 34 Upper channel protrusion 35 Connecting recess 36 Wall 40 Lower liquid flow path section 41 Mainstream groove 50 Spacer member 70 Lower heat seal layer 71 Upper heat-sealed layer 80 Steam flow passage 83 Frame body part 83a Bottom surface of frame body 83b Frame top surface 84 Land Department 84a Land bottom 84b Land top surface 91 1st support part 92 Second support part 93 Wick sheet alignment hole 94 Wick sheet protrusion 95 Injection Channel 96 Lower land liquid flow path 97 Lower frame body fluid flow path section 98 Upper liquid flow path 99 Upper land liquid flow passage 100 Upper frame body fluid flow path part 111 Lower body sheet 112 Lower reinforcement sheet 121 Upper body sheet 122 Upper reinforcement sheet

Claims

[Claim 1] A wick sheet for a vapor chamber, the wick sheet being interposed between a first sheet and a second sheet and having a sealed space in which a working fluid is sealed, a first surface that contacts the first sheet; a second surface provided on the opposite side to the first surface and in contact with the second sheet; a liquid flow path portion provided on the first surface, constituting a part of the sealed space, through which the liquid working fluid passes; A wick sheet for a vapor chamber comprising: a vapor flow path portion provided on the second surface, communicating with the liquid flow path portion to form part of the sealed space, and through which vapor of the working liquid passes.

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