JP2023052200A - Vapor chamber and mobile terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vapor chamber that can enhance capillary action while reducing flow passage resistance of working liquid.

SOLUTION: A vapor chamber 1 according to the present invention comprises a first metal sheet 10, and a second metal sheet 20 provided on the first metal sheet 10, and forming a sealed space 3 between itself and the first metal sheet 10. A first contact surface 13a of the first metal sheet 10 is provided with a first liquid flow passage concave part 30 for conveying working liquid 2 condensed from vapor to an evaporation part 11. The first liquid flow passage concave part 30 comprises a first concave part opening part 31, and a first large width part 32 provided closer to a bottom side of the first liquid flow passage concave part 30 than the first concave part opening part 31. In a cross section of the first liquid flow passage concave part 30, the width of the first large width part 32 is larger than the width of the first concave part opening part 31.

SELECTED DRAWING: Figure 6

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to a vapor chamber having a sealed space in which hydraulic fluid is sealed and a metal sheet for the vapor chamber.

Devices that generate heat, such as central processing units (CPUs) used in mobile terminals such as mobile terminals and tablet terminals, are cooled by heat-dissipating members such as heat pipes (see, for example, Patent Documents 1 to 4). . In recent years, in order to reduce the thickness of mobile terminals and the like, there has been a demand for thinner heat dissipating members, and the development of vapor chambers that can be made thinner than heat pipes is underway. A working fluid is sealed in the vapor chamber, and the working fluid absorbs the heat of the device and releases it to the outside, thereby cooling the device.

More specifically, the working fluid in the vapor chamber receives heat from the device at the portion (evaporation section) close to the device and evaporates into vapor, and then the vapor moves to a position away from the vaporization section. It cools down and condenses into a liquid. Inside the vapor chamber, a recessed liquid flow path is provided as a capillary structure (wick), and the liquid working fluid passes through the recessed liquid flow path, is transported to the evaporator, and is again transported to the evaporator. Evaporate under heat. In this way, the working fluid circulates in the vapor chamber while repeating phase changes, that is, evaporation and condensation, thereby transferring heat in the device and increasing heat transport efficiency.

JP-A-11-31768 Japanese Unexamined Patent Application Publication No. 2007-212028 JP 2015-59693 A JP 2016-17702 A

In order to increase the heat transport efficiency of the vapor chamber, it is desirable to efficiently transport the working fluid in the vapor chamber to the evaporator. In this case, the recessed liquid flow path is required to have a low flow path resistance of the hydraulic fluid passing through the recessed liquid flow path and a high capillary action.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vapor chamber and a metal sheet for a vapor chamber that can increase the capillary action while reducing the flow path resistance of the hydraulic fluid. .

The present invention
A vapor chamber having a sealed space in which a hydraulic fluid is enclosed,
a first metal sheet;
a second metal sheet provided on the first metal sheet and forming the sealed space with the first metal sheet;
The first metal sheet is provided on the surface on the side of the second metal sheet, constitutes a part of the sealed space, and includes a first vapor flow path concave portion through which the vapor of the working fluid passes, and the first vapor flow. a first channel wall portion including a first contact surface that protrudes from the bottom surface of the channel recess and contacts the second metal sheet;
The first contact surface is provided with a first liquid flow path recess that constitutes a part of the sealed space and through which the liquid working liquid passes,
The first liquid flow path recess has a first recess opening and a first large portion provided closer to the bottom side of the first liquid flow path recess than the first recess opening,
In the cross section of the first liquid flow path recess, the width of the first large portion is greater than the width of the opening of the first recess,
vapor chamber,
I will provide a.

In addition, in the vapor chamber described above,
The cross section of the first liquid flow path recess is formed in an arc shape,
You may do so.

Also, in the vapor chamber described above,
The second metal sheet is provided on the side of the first metal sheet and constitutes a part of the sealed space. a second channel wall portion including a second contact surface protruding from the bottom surface of the channel recess and contacting the first metal sheet;
The second contact surface is provided with a second liquid flow path recess that constitutes a part of the sealed space and through which the liquid working liquid passes,
The second liquid flow path recess has a second recess opening and a second large portion provided closer to the bottom side of the second liquid flow path recess than the second recess opening,
In the cross section of the second liquid flow path recess, the width of the second large portion is larger than the width of the opening of the second recess,
You may do so.

Also, in the vapor chamber described above,
The first liquid flow path recess and the second liquid flow path recess are opposed to each other,
You may do so.

Also, in the vapor chamber described above,
A part of the second contact surface is exposed in the first liquid flow path recess,
You may do so.

Also, in the vapor chamber described above,
A part of the first contact surface is exposed to the second liquid flow path recess,
You may do so.

In addition, the present invention
A vapor chamber metal sheet for a vapor chamber having a sealed space in which a hydraulic fluid is enclosed,
a vapor flow channel recess forming part of the sealed space, through which the vapor of the working fluid passes;
a channel wall portion including a protruding end face that protrudes from the bottom surface of the steam channel recess,
A liquid flow path concave portion through which the liquid working fluid passes is provided on the projecting end surface,
The liquid flow path recess has a recess opening and a large portion provided closer to the bottom side of the liquid flow path recess than the recess opening,
In the cross section of the liquid flow path recess, the width of the large portion is larger than the width of the recess opening.
metal sheet for vapor chamber,
I will provide a.

Furthermore, the present invention provides
A vapor chamber having a sealed space in which a hydraulic fluid is enclosed,
a first metal sheet;
a second metal sheet provided on the first metal sheet and forming the sealed space with the first metal sheet;
The first metal sheet is provided on the surface on the side of the second metal sheet, constitutes a part of the sealed space, and includes a first vapor flow path concave portion through which the vapor of the working fluid passes, and the first vapor flow. a first channel wall portion including a first contact surface that protrudes from the bottom surface of the channel recess and contacts the second metal sheet;
The second metal sheet is provided on the side of the first metal sheet and constitutes a part of the sealed space. a second channel wall portion including a second contact surface protruding from the bottom surface of the channel recess and contacting the first metal sheet;
The first contact surface is provided with a first liquid flow path recess that constitutes a part of the sealed space and through which the liquid working liquid passes,
The second contact surface is provided with a second liquid flow path recess that constitutes a part of the sealed space and through which the liquid working liquid passes,
the first liquid flow path recess and the second liquid flow path recess are opposed to each other,
A part of the second contact surface is exposed to the first liquid flow path recess, or a part of the first contact surface is exposed to the second liquid flow path recess,
vapor chamber,
I will provide a.

In addition, in the vapor chamber described above,
A part of the second contact surface is exposed in the first liquid flow path recess, and a part of the first contact surface is exposed in the second liquid flow path recess,
You may do so.

ADVANTAGE OF THE INVENTION According to this invention, a capillary action can be improved, reducing the flow-path resistance of a hydraulic fluid.

FIG. 1 is a top view showing a vapor chamber according to a first embodiment of the invention. FIG. 2 is a cross-sectional view taken along the line AA showing the vapor chamber of FIG. 1. FIG. 3 is a top view of the lower metal sheet of FIG. 1; FIG. 4 is a bottom view of the upper metal sheet of FIG. 1; FIG. FIG. 5 is an enlarged top view of the B portion showing the liquid flow path concave portion of FIG. 6 is an enlarged cross-sectional view of the portion C showing the liquid flow path concave portion of FIG. 2. FIG. FIG. 7 is a diagram for explaining a step of preparing a metal material sheet in the vapor chamber manufacturing method of FIG. FIG. 8 is a diagram for explaining the half-etching step of the metal material sheet in the vapor chamber manufacturing method of FIG. FIG. 9 is a diagram for explaining the step of forming a resist film on the upper surface of the metal material sheet in the half-etching step of FIG. FIG. 10 is a diagram for explaining the patterning process of the resist film of FIG. 9 in the half-etching process of FIG. FIG. 11 is a diagram for explaining the half-etching process of the metal material sheet in the half-etching process of FIG. 12A and 12B are diagrams for explaining the step of removing the resist film in the half-etching step of FIG. 13A and 13B are diagrams for explaining a temporary fixing step in the manufacturing method of the vapor chamber of FIG. 1. FIG. FIG. 14 is a diagram for explaining a permanent bonding step in the vapor chamber manufacturing method of FIG. 15A and 15B are diagrams for explaining a working fluid filling step in the method of manufacturing the vapor chamber of FIG. 1. FIG. FIG. 16 is a diagram showing a modification (modification 1) of FIG. FIG. 17 is a diagram showing another modification (modification 2) of FIG. FIG. 18 is an enlarged cross-sectional view showing the liquid flow path recess in the vapor chamber according to the second embodiment of the present invention. 19 is a diagram showing a modification (modification 3) of FIG. 18. FIG. FIG. 20 is a diagram showing another modification (modification 4) of FIG. 21 is a diagram showing another modification (modification 5) of FIG. 18. FIG. FIG. 22 is a diagram showing another modification (modification 6) of FIG. 23 is a diagram showing another modification (modification 7) of FIG. 18. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings attached to this specification, for the sake of ease of illustration and understanding, the scale, length-to-width ratio, etc. are appropriately changed and exaggerated from those of the real thing.

(First embodiment)
A vapor chamber and a vapor chamber metal sheet according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 17. FIG. The vapor chamber 1 according to the present embodiment has a sealed space 3 in which a working fluid 2 is enclosed. It is a device for cooling a device D (device to be cooled) that generates heat such as a central processing unit (CPU) used in, for example. The vapor chamber 1 is generally formed in the shape of a thin flat plate.

As shown in FIGS. 1 and 2, the vapor chamber 1 includes a lower metal sheet 10 (first metal sheet) having an upper surface 10a and an upper metal sheet 20 (second metal sheet) provided on the lower metal sheet 10. seat) and Both the lower metal sheet 10 and the upper metal sheet 20 correspond to vapor chamber metal sheets. The upper metal sheet 20 has a lower surface 20a (the surface on the side of the lower metal sheet 10) that overlaps the upper surface 10a of the lower metal sheet 10 (the surface on the side of the upper metal sheet 20). A device D, which is an object to be cooled, is attached to the lower surface 10b of the lower metal sheet 10 (in particular, the lower surface of the evaporator 11, which will be described later).

Between the lower metal sheet 10 and the upper metal sheet 20, a sealed space 3 is formed in which the hydraulic fluid 2 is enclosed. Examples of the working liquid 2 include pure water, ethanol, methanol, acetone, and the like.

The lower metal sheet 10 and the upper metal sheet 20 are bonded by diffusion bonding, which will be described later. 1 and 2 show an example in which both the lower metal sheet 10 and the upper metal sheet 20 are formed in a rectangular shape in a plan view, but they are not limited to this. Here, the plane view is a direction perpendicular to the surface of the vapor chamber 1 that receives heat from the device D (the lower surface 10b of the lower metal sheet 10) and the surface that releases the received heat (the upper surface 20b of the upper metal sheet 20). 1, which corresponds to, for example, the vapor chamber 1 viewed from above (see FIG. 1) or from below.

When the vapor chamber 1 is installed in a mobile terminal, the vertical relationship between the lower metal sheet 10 and the upper metal sheet 20 may be disrupted depending on the orientation of the mobile terminal. However, in the present embodiment, the metal sheet that receives heat from the device D is called the lower metal sheet 10, the metal sheet that releases the received heat is called the upper metal sheet 20, and the lower metal sheet 10 is the lower side. , and the upper metal sheet 20 is arranged on the upper side.

As shown in FIG. 3, the lower metal sheet 10 includes an evaporator 11 in which the working fluid 2 evaporates to generate steam, and a lower steam channel provided on the upper surface 10a and formed in a rectangular shape in plan view. and a concave portion 12 (first steam flow channel concave portion). Of these, the lower steam flow passage concave portion 12 constitutes a part of the sealed space 3 described above, and is mainly configured so that the steam generated in the evaporating portion 11 passes therethrough.

The evaporating section 11 is arranged in the lower steam channel recess 12, and the steam in the lower steam channel recess 12 diffuses away from the evaporating section 11, and most of the steam is relatively It is transported to the cooler periphery. The evaporating portion 11 is a portion where the working fluid 2 in the sealed space 3 evaporates by receiving heat from the device D attached to the lower surface 10b of the lower metal sheet 10 . Therefore, the term evaporating portion 11 is not limited to the portion overlapping the device D, but is used as a concept including the portion where the working fluid 2 can evaporate even if it does not overlap the device D. Here, the evaporator 11 can be provided at any location on the lower metal sheet 10, but FIGS. 1 and 3 show an example in which it is provided at the central portion of the lower metal sheet 10. . In this case, it is possible to prevent 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 .

In the present embodiment, as shown in FIGS. 2 and 3, in the lower steam channel recessed portion 12 of the lower metal sheet 10, from the bottom surface 12a (described later) of the lower steam channel recessed portion 12 to the upper side (bottom surface 12a). A plurality of lower flow path wall portions 13 (first flow path wall portions) projecting in a direction perpendicular to the vertical direction) are provided. In the present embodiment, an example in which the lower flow path wall portion 13 extends in an elongated shape along the longitudinal direction of the vapor chamber 1 (horizontal direction in FIG. 3) is shown, and the upper flow path described later. It includes an upper surface 13 a (first contact surface, projecting end surface) that contacts the lower surface 22 a of the wall portion 22 . In addition, the respective lower flow path wall portions 13 are arranged in parallel with each other at regular intervals. In this manner, the vapor of the working fluid 2 flows around each lower flow path wall portion 13 and is transported to the peripheral edge portion of the lower vapor flow path concave portion 12. Prevents obstruction of flow. In addition, the lower channel wall portion 13 is arranged so as to overlap a corresponding upper channel wall portion 22 (described later) of the upper metal sheet 20 in a plan view, thereby improving the mechanical strength of the vapor chamber 1 . ing. The width w0 of the lower channel wall portion 13 is, for example, 100 μm to 1500 μm, and the interval d between the adjacent lower channel wall portions 13 is preferably 100 μm to 2000 μm. Here, the width w0 means the dimension of the lower channel wall portion 13 in the direction orthogonal to the longitudinal direction of the lower channel wall portion 13, for example, the vertical dimension in FIGS. Equivalent to. Also, the height of the lower flow path wall portion 13 (in other words, the depth of the lower steam flow path concave portion 12) h0 (see FIG. 2) is preferably 100 μm to 300 μm.

As shown in FIGS. 2 and 3, a lower peripheral wall 14 is provided at the peripheral edge of the lower metal sheet 10 . The lower peripheral wall 14 is formed so as to surround the sealed space 3 , particularly the lower steam channel recess 12 , and defines the sealed space 3 . Lower alignment holes 15 for positioning the lower metal sheet 10 and the upper metal sheet 20 are provided at the four corners of the lower peripheral wall 14 in plan view.

In the present embodiment, the upper metal sheet 20 has substantially the same structure as the lower metal sheet 10, except that the lower liquid flow path concave portion 30, which will be described later, is not provided. The configuration of the upper metal sheet 20 will be described in more detail below.

As shown in FIGS. 2 and 4, the upper metal sheet 20 has an upper steam channel recess 21 (second steam channel recess) provided on the lower surface 20a. The upper steam flow passage concave portion 21 constitutes a part of the sealed space 3 and is mainly configured so that the steam generated in the evaporating portion 11 passes through and cools the steam. More specifically, the steam in the upper steam passage concave portion 21 diffuses away from the evaporating portion 11, and most of the steam is transported to the peripheral portion where the temperature is relatively low. Further, as shown in FIG. 2, on the upper surface 20b of the upper metal sheet 20 is arranged a housing member H that constitutes a part of the housing of a mobile terminal or the like. As a result, the steam in the upper steam passage recess 21 is cooled by the outside air through the upper metal sheet 20 and the housing member H.

In the present embodiment, as shown in FIGS. 1 and 4, the ceiling surface 21a of the upper steam channel recess 21 (the upper metal sheet 20 is turned upside down) is provided in the upper steam channel recess 21 of the upper metal sheet 20. A plurality of upper flow path wall portions 22 (second flow path wall portions) protruding downward (in a direction perpendicular to the ceiling surface 21a) are provided. . In the present embodiment, an example in which the upper flow path wall portion 22 extends in an elongated shape along the longitudinal direction of the vapor chamber 1 (horizontal direction in FIG. 4) is shown, and the upper flow path wall portion 22 extends in an elongated shape along the above-described lower flow path wall. It includes a lower surface 22a (second contact surface, projecting end surface) that contacts the upper surface 13a of the portion 13 . Moreover, each upper flow-path wall part 22 is spaced apart by equal intervals, and is mutually arrange|positioned in parallel. In this manner, the vapor of the working fluid 2 flows around each upper flow path wall portion 22 and is transported to the peripheral edge portion of the upper vapor flow path concave portion 21. Avoid being hindered. In addition, the upper channel wall portion 22 is arranged so as to overlap the corresponding lower channel wall portion 13 of the lower metal sheet 10 in a plan view, thereby improving the mechanical strength of the vapor chamber 1. . The width and height of the upper channel wall portion 22 are preferably the same as the width w0 and height h0 of the lower channel wall portion 13 described above.

As shown in FIGS. 2 and 4, the upper metal sheet 20 has an upper peripheral wall 23 at its peripheral edge. The upper peripheral wall 23 is formed so as to surround the sealed space 3 , particularly the upper steam channel recess 21 , and defines the sealed space 3 . Further, upper alignment holes 24 for positioning the lower metal sheet 10 and the upper metal sheet 20 are provided at the four corners of the upper peripheral wall 23 in plan view. That is, each upper alignment hole 24 is arranged so as to overlap with each lower alignment hole 15 described above at the time of temporary fixing, which will be described later, so that the lower metal sheet 10 and the upper metal sheet 20 can be positioned. .

Such lower metal sheet 10 and upper metal sheet 20 are permanently bonded together, preferably by diffusion bonding. More specifically, as shown in FIG. 2, the upper surface 14a of the lower peripheral wall 14 of the lower metal sheet 10 and the lower surface 23a of the upper peripheral wall 23 of the upper metal sheet 20 are in contact with each other. 14 and the upper peripheral wall 23 are joined together. As a result, a sealed space 3 in which the hydraulic fluid 2 is sealed is formed between the lower metal sheet 10 and the upper metal sheet 20 . Further, the upper surface 13a of the lower flow channel wall portion 13 of the lower metal sheet 10 and the lower surface 22a of the upper flow channel wall portion 22 of the upper metal sheet 20 abut against each lower flow channel wall portion 13. The upper channel wall portion 22 is joined to each other. This improves the mechanical strength of the vapor chamber 1 . In particular, since the lower channel wall portion 13 and the upper channel wall portion 22 according to the present embodiment are arranged at regular intervals, the mechanical strength at each position of the vapor chamber 1 can be made uniform. Note that the lower metal sheet 10 and the upper metal sheet 20 may be joined by other methods such as brazing instead of diffusion joining as long as they can be joined permanently.

In addition, as shown in FIG. 1, the vapor chamber 1 further includes an injection part 4 for injecting the working fluid 2 into the sealed space 3 at one of the pair of longitudinal ends. The injection part 4 has a lower injection projection 16 projecting from the end surface of the lower metal sheet 10 and an upper injection projection 25 projecting from the end surface of the upper metal sheet 20 . A lower injection channel recess 17 is formed on the upper surface of the lower injection projection 16 , and an upper injection channel recess 26 is formed on the lower surface of the upper injection projection 25 . The lower injection channel recess 17 communicates with the lower steam channel recess 12 , and the upper injection channel recess 26 communicates with the upper steam channel recess 21 . The lower injection channel recess 17 and the upper injection channel recess 26 form injection channels for the working liquid 2 when the lower metal sheet 10 and the upper metal sheet 20 are joined. The working fluid 2 is injected into the sealed space 3 through the injection channel. In addition, in the present embodiment, an example in which the injection part 4 is provided at one end of a pair of ends in the longitudinal direction of the vapor chamber 1 is shown, but it is not limited to this. do not have.

Next, the lower liquid flow path recesses 30 of the lower metal sheet 10 will be described in more detail with reference to FIGS. 3, 5 and 6. FIG.

As shown in FIGS. 3 and 5, the upper surface 13a of each lower flow path wall portion 13 is provided with a lower liquid flow path recess 30 (first liquid flow path recess) through which the liquid working fluid 2 passes. . More specifically, the lower liquid flow channel recess 30 is formed on the upper surface 13 a of the lower flow channel wall 13 . The lower liquid flow channel recess 30 constitutes a part of the above-described sealed space 3 and communicates with the above-described lower steam flow channel recess 12 and upper steam flow channel recess 21 . The lower liquid flow path recess 30 is mainly configured to transport the working fluid 2 condensed from the vapor generated in the evaporator 11 to the evaporator 11 . In the present embodiment, an example in which the lower liquid flow channel recessed portion 30 extends in an elongated shape along the longitudinal direction of the lower flow channel wall portion 13 (horizontal direction in FIG. 3) is shown. It extends from one end to the other end in the longitudinal direction of the side channel wall portion 13 . In this manner, the liquid working fluid 2 condensed at the peripheral edge of the lower steam channel recess 12 and the peripheral edge of the upper steam channel recess 21 is transported to the evaporator 11 by capillary action. A plurality of lower liquid flow channel recesses 30 are formed on the upper surface 13a of one lower flow channel wall portion 13, and the respective lower liquid flow channel recesses 30 are spaced apart at equal intervals and parallel to each other. are placed.

Although not shown, each lower liquid flow path recess 30 communicates with the lower steam flow path recess 12 in the evaporator 11 as well. For example, a liquid flow path recess extending in a direction crossing the lower liquid flow path recesses 30 (the vertical direction in FIGS. 3 and 5) is provided, and the liquid flow path recesses are aligned with the respective lower liquid flow path recesses 30 and below. You may make it connect with the side steam-flow-path recessed part 12. FIG. Alternatively, in the evaporating section 11, the lower surface 22a of the upper flow passage wall portion 22 is separated from the upper surface 13a of the lower flow passage wall portion 13, and the space between the upper surface 13a and the lower surface 22a is defined as the lower vapor flow. The passage recess 12 and the upper steam passage recess 21 may be communicated with each other.

As shown in FIG. 6, the lower liquid flow channel recess 30 is formed on the upper surface 13a of the lower flow channel wall 13 and opens upward. That is, the lower liquid flow path recess 30 includes a lower recess opening 31 (first recess opening) and a lower recess located on the bottom side of the lower liquid flow path recess 30 relative to the lower recess opening 31. and a large portion 32 (first large portion). The lower recessed portion opening 31 is an opening at a position corresponding to the upper surface 13 a of the lower flow path wall portion 13 in the lower liquid flow path recessed portion 30 . The lower large portion 32 is arranged closer to the bottom in FIG. 6 than the lower recess opening 31 .

The lower liquid flow path recess 30 is formed (inverted tapered) so as to expand from the lower recess opening 31 toward the bottom side of the lower liquid flow path recess 30 . More specifically, the width gradually increases from the lower concave portion opening 31 toward the bottom side, and the width of the lower liquid flow channel concave portion 30 is maximum at the lower large portion 32 . The width gradually decreases from the lower large portion 32 toward the bottom side. Thus, in the present embodiment, the width w2 of the lower wide portion 32 is larger than the width w1 of the lower recess opening 31 in the cross section of the lower liquid flow path recess 30 . In addition, the cross section means a cross section perpendicular to the longitudinal direction of the lower liquid flow path concave portion 30 .

As shown in FIG. 6, the cross section of the lower liquid flow path concave portion 30 is preferably formed in an arc shape. Here, the cross section of the lower liquid flow path concave portion 30 is formed in a C shape. It can also be said that the cross-sectional shape of such a lower liquid flow path concave portion 30 is an octopus pot shape.

Widths w1 and w2 of the lower liquid flow channel recess 30 are smaller than the width w0 of the lower flow channel wall 13 . As a result, the lower liquid flow path concave portion 30 is filled with the liquid working fluid 2 condensed from the vapor of the working fluid 2, and the filled liquid working fluid 2 is transported to the evaporating portion 11 by capillary action. be. On the other hand, since the lower steam channel recess 12 and the upper steam channel recess 21 have channel cross-sectional areas larger than the channel cross-sectional area of the lower liquid channel recess 30, Vapors of the working fluid 2 produced pass through.

The widths w1 and w2 of the lower liquid flow path recess 30 mean the dimensions of the lower liquid flow path recess 30 in the direction perpendicular to the longitudinal direction of the lower liquid flow path recess 30. It corresponds to the dimension in the direction, or the dimension in the horizontal direction in FIG. Width w1 is preferably between 10 μm and 100 μm, and width w2 is preferably between 20 μm and 150 μm. The width w1 and the width w2 can be adjusted by controlling the spray pressure of the etchant when forming the lower liquid flow path concave portion 30 by half-etching, as will be described later. Further, the depth h1 of the lower liquid flow path concave portion 30 is preferably 20 μm to 150 μm, depending on the width w1 and width w2.

Such a lower liquid flow channel concave portion 30 is formed on the upper surface 13 a of the lower flow channel wall portion 13 of the lower metal sheet 10 . On the other hand, in the present embodiment, the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20 is not formed with an upper liquid flow path concave portion 35 (see FIG. 16), which will be described later. That is, the lower surface 22 a is flat and exposed to the lower liquid flow path concave portion 30 . In this way, in the cross section of the lower liquid flow path recess 30 , the entire lower liquid flow path recess 30 is covered with the flat lower surface 22 a of the upper flow path wall 22 .

By the way, the materials used for the lower metal sheet 10 and the upper metal sheet 20 are not particularly limited as long as they have good thermal conductivity. Alternatively, it is preferably made of a copper alloy. Thereby, the thermal conductivity of the lower metal sheet 10 and the upper metal sheet 20 can be increased. Therefore, the heat transport efficiency of the vapor chamber 1 can be enhanced. Also, the thickness of the vapor chamber 1 is 0.1 mm to 1.0 mm. Although the thickness T1 of the lower metal sheet 10 and the thickness T2 of the upper metal sheet 20 are shown to be equal, the thickness T1 of the lower metal sheet 10 and the thickness T2 of the upper metal sheet 20 are not limited to this. The thicknesses T2 need not be equal.

Next, the operation of this embodiment having such a configuration will be described. Here, first, the manufacturing method of the vapor chamber 1 will be described with reference to FIGS. 7 to 15, but the description of the half etching process for the upper metal sheet 20 will be simplified. 7, 8, and 13 to 15 show cross sections similar to the cross section of FIG. 2, and FIGS. 9 to 12 show cross sections similar to the cross section of FIG.

First, as shown in FIG. 7, a flat metal material sheet M is prepared.

Subsequently, as shown in FIG. 8, the metal material sheet M is half-etched to form the lower steam channel recess 12 and the lower liquid channel recess 30 that form part of the sealed space 3 .

In this case, first, a resist film 40 is formed on the upper surface Ma of the metal material sheet M, as shown in FIG. For the resist film 40, an electrodeposition resist material that can be adhered by an electric field can be preferably used. may

Subsequently, as shown in FIG. 10, the resist film 40 is patterned. That is, the resist film 40 is formed in a pattern corresponding to the lower vapor flow channel recesses 12 and the plurality of lower liquid flow channel recesses 30 by photolithography, and resist openings corresponding to the lower vapor flow channel recesses 12 are formed. 42a and resist openings 42b corresponding to the lower liquid flow path recesses 30 are formed.

Subsequently, as shown in FIG. 11, the upper surface Ma of the metal material sheet M is half-etched as a half-etching step. As a result, portions of the upper surface Ma corresponding to the resist openings 42a and 42b of the resist film 40 are half-etched, and the lower steam channel recess 12, the lower channel wall 13, and the lower peripheral wall 14 are formed. It is formed. At this time, the lower liquid flow path concave portion 30 is formed on the upper surface 13 a of the lower flow path wall portion 13 . 1 and 3 are also formed at the same time, and the metal material sheet M is etched from the upper surface Ma and the lower surface so as to have the contour shape as shown in FIG. A predetermined contour shape is obtained. Note that half-etching means etching for forming recesses that do not penetrate the material. Therefore, the depth of the recess formed by half-etching is not limited to half the thickness of the lower metal sheet 10 . As the etchant, for example, an iron chloride-based etchant such as an aqueous ferric chloride solution or a copper chloride-based etchant such as an aqueous copper chloride solution can be used.

The half-etching here is preferably spray etching in which an etchant is sprayed onto the upper surface Ma of the metal material sheet M. As shown in FIG. In the case of spray etching, the upper surface Ma of the metal material sheet M is spray-etched, for example, at a pressure of 1 kg/cm ² or more, thereby forming the lower liquid flow path concave portion 30 shown in FIG. 6 with a width w1 larger than the width w2. can be formed. The cross-sectional shape of the lower steam channel recess 12 formed together with the lower liquid channel recess 30 is also formed in the same octopus pot shape (arc shape or C shape) as the lower liquid channel recess 30. may That is, the lower steam flow channel concave portion 12 may be formed so as to bulge from the opening toward the bottom (inversely tapered). In this case, the channel cross-sectional area of the lower vapor channel concave portion 12 can be increased to reduce the channel resistance of the vapor of the working fluid 2 .

Here, the etching of the lower liquid flow path concave portion 30 is affected by the opening area of the lower concave portion opening portion 31 and the thickness of the resist film 40, but in general, the etching of copper by the ferric chloride aqueous solution is performed. Since the etching is diffusion rate controlled, the portion to which the fresh ferric chloride aqueous solution is supplied before the reaction tends to be easily etched. On the other hand, the ferric chloride aqueous solution consumed in the etching reaction deteriorates in etching ability. Therefore, in the case of high-pressure spray etching using an aqueous ferric chloride solution, unreacted fresh ferric chloride aqueous solution flows from the lower recessed portion opening 31 of the lower liquid flow channel recessed portion 30 to the lower liquid. Since the liquid is supplied toward the bottom of the channel recess 30, the bottom of the lower liquid channel recess 30 and the inner wall near the bottom are easily etched. On the other hand, in the vicinity of the lower recessed portion opening 31 of the lower liquid flow channel recessed portion 30, the ferric chloride aqueous solution with deteriorated etching ability tends to remain. The inner wall near the opening 31 of the recess is difficult to etch. In this manner, the lower liquid flow path concave portion 30 according to the present embodiment can be obtained by performing spray etching with increased pressure.

After that, as shown in FIG. 12, the resist film 40 is removed. Thus, as shown in FIG. 8, the lower metal sheet 10 in which the lower steam channel recess 12, the lower channel wall 13, the lower peripheral edge wall 14 and the lower liquid channel recess 30 are formed. is obtained. In this way, by forming the lower vapor channel recess 12, the lower channel wall 13, the lower peripheral wall 14, and the lower liquid channel recess 30 in one half-etching process, the half-etching process can be The number of times can be reduced, and the manufacturing cost of the vapor chamber 1 can be reduced. However, it is not limited to this, and as a first half-etching process, the lower vapor channel recess 12, the lower channel wall 13 and the lower peripheral wall 14 are formed, and then the second half-etching process is performed. As an etching process, the lower liquid flow path concave portion 30 may be formed in the upper surface 13 a of the lower flow path wall portion 13 . In this case, the depth h0 of the lower vapor channel recess 12 and the depth h1 of the lower liquid channel recess 30 can be easily made different.

On the other hand, in the same manner as the lower metal sheet 10, the upper metal sheet 20 is half-etched from the lower surface 20a to form the upper steam channel concave portion 21, the upper channel wall portion 22 and the upper peripheral edge wall . Thus, the upper metal sheet 20 described above is obtained.

Next, as shown in FIG. 13, the lower metal sheet 10 having the lower steam channel recess 12 and the upper metal sheet 20 having the upper steam channel recess 21 are temporarily fixed. In this case, first, using the lower alignment hole 15 (see FIGS. 1 and 3) of the lower metal sheet 10 and the upper alignment hole 24 (see FIGS. 1 and 4) of the upper metal sheet 20, A metal sheet 10 and an upper metal sheet 20 are positioned. Subsequently, the lower metal sheet 10 and the upper metal sheet 20 are fixed. The fixing method is not particularly limited, but for example, the lower metal sheet 10 and the upper metal sheet 20 are fixed by performing resistance welding on the lower metal sheet 10 and the upper metal sheet 20. may In this case, as shown in FIG. 13, it is preferable to perform spot resistance welding using electrode rods 43 . Laser welding may be performed instead of resistance welding. Alternatively, the lower metal sheet 10 and the upper metal sheet 20 may be ultrasonically bonded and fixed by irradiating ultrasonic waves. Furthermore, although an adhesive may be used, it is preferable to use an adhesive that does not have an organic component or has a small amount of an organic component. Thus, the lower metal sheet 10 and the upper metal sheet 20 are fixed in a positioned state.

After temporary fixing, the lower metal sheet 10 and the upper metal sheet 20 are permanently joined by diffusion bonding, as shown in FIG. In diffusion bonding, the lower metal sheet 10 and the upper metal sheet 20 to be bonded are brought into close contact, and pressure is applied in a controlled atmosphere such as vacuum or inert gas in a direction to bring the metal sheets 10 and 20 into close contact. It is a method of bonding by heating together and utilizing diffusion of atoms occurring on the bonding surface. Diffusion bonding heats the materials of the lower metal sheet 10 and the upper metal sheet 20 to a temperature close to the melting point, but below the melting point, thereby avoiding melting and deformation of each metal sheet 10,20. More specifically, the upper surface 14a of the lower peripheral wall 14 of the lower metal sheet 10 and the lower surface 23a of the upper peripheral wall 23 of the upper metal sheet 20 are diffusion-bonded as bonding surfaces. Thereby, the sealed space 3 is formed between the lower metal sheet 10 and the upper metal sheet 20 by the lower peripheral wall 14 and the upper peripheral wall 23 . In addition, the lower injection channel recess 17 (see FIGS. 1 and 3) and the upper injection channel recess 26 (see FIGS. 1 and 4) form an injection channel for the hydraulic fluid 2 communicating with the sealed space 3. be done. Further, the upper surface 13a of the lower flow path wall portion 13 of the lower metal sheet 10 and the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20 are diffusion-bonded as bonding surfaces to form the vapor chamber 1. Improves mechanical strength. The lower liquid flow channel recess 30 formed in the upper surface 13 a of the lower flow channel wall 13 remains as a flow channel for the liquid working fluid 2 .

After permanent bonding, as shown in FIG. 15, the working fluid 2 is injected into the sealed space 3 from the injection part 4 (see FIG. 1). At this time, first, the sealed space 3 is evacuated to reduce the pressure, and then the working fluid 2 is injected into the sealed space 3 . During injection, the working liquid 2 passes through the injection channel formed by the lower injection channel recess 17 and the upper injection channel recess 26 .

After the injection of the working liquid 2, the injection channel mentioned above is sealed. For example, it is preferable to irradiate the injection part 4 with a laser to partially melt the injection part 4 to seal the injection channel. As a result, communication between the sealed space 3 and the outside air is cut off, and the working fluid 2 is enclosed in the sealed space 3 . Thus, the hydraulic fluid 2 in the sealed space 3 is prevented from leaking to the outside.

As described above, the vapor chamber 1 according to the present embodiment is obtained.

Next, a method of operating the vapor chamber 1, that is, a method of cooling the device D will be described.

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 object to be cooled, is attached to the lower surface 10b 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 is pushed by the surface tension of the wall surface of the sealed space 3, that is, the lower steam flow channel recess 12. It adheres to the wall surface and the wall surface of the upper steam channel recess 21 .

When the device D heats up in this state, the working fluid 2 existing in the evaporating portion 11 of the lower steam flow channel concave portion 12 receives heat from the device D. As shown in FIG. The received heat is absorbed as latent heat, and the working fluid 2 evaporates (vaporizes) to generate vapor of the working fluid 2 . Most of the generated steam diffuses into the lower steam channel recess 12 and the upper steam channel recess 21 that form the sealed space 3 (see solid line arrows in FIGS. 3 and 4). The steam in the upper steam channel recess 21 and the lower steam channel recess 12 leaves the evaporating section 11, and most of the steam is transported to the peripheral portion where the temperature is relatively low. The vapor diffused to the peripheral portion is cooled by radiating heat at the peripheral portion. The heat received by the lower metal sheet 10 and the upper metal sheet 20 from the steam at the periphery is transferred to the outside air through the housing member H (see FIG. 2).

The steam loses the latent heat absorbed in the evaporator 11 by radiating heat to the peripheral portion and condenses. Most of the liquefied working fluid 2 adheres to the wall surface of the lower steam channel recess 12 or the wall surface of the upper steam channel recess 21 and reaches the lower liquid channel recess 30 . Here, since the working fluid 2 continues to evaporate in the evaporating portion 11, the working fluid 2 in the portion other than the evaporating portion 11 of the lower liquid flow passage concave portion 30 is transported toward the evaporating portion 11 by capillary action. (see dashed arrow in FIG. 3). As a result, the liquid working fluid 2 adhering to the wall surface of the lower steam flow channel recess 12 and the wall surface of the upper steam flow channel recess 21 is removed from the lower liquid flow channel recess 30 by the lower steam flow channel recess 12 or the upper steam flow channel recess 21 . It moves toward both ends in the longitudinal direction of the lower liquid flow channel recess 30 opened toward the flow channel recess 21 and enters the lower liquid flow channel recess 30 from the both ends. As a result, the liquid working fluid 2 is filled in the lower liquid flow path recess 30 , and the filled working fluid 2 exerts a driving force toward the evaporator 11 due to the capillary action of the lower liquid flow path recess 30 . and is smoothly transported toward the evaporating section 11 .

In the present embodiment, the width w2 of the lower large portion 32 of the lower liquid flow path recess 30 is larger than the width w1 of the lower recess opening 31 . That is, as shown in FIG. 6, since the lower liquid flow path recess 30 is formed to swell from the lower recess opening 31 toward the bottom side, the cross section of the lower liquid flow path recess 30 , the length of the outline of the lower liquid flow path recess 30 can be lengthened. For example, the lower liquid flow channel recess 30 according to the present embodiment can have a longer outline than the forward tapered liquid flow channel recess 50 as shown in FIG. In this case, the area of the wall surface of the lower liquid flow path recessed portion 30 can be increased, and the area of contact between the wall surface of the lower liquid flow path recessed portion 30 and the liquid working fluid 2 can be increased. Therefore, it is possible to increase the capillary action that the liquid working fluid 2 passing through the lower liquid flow path concave portion 30 receives, so that the working fluid 2 can be smoothly transported toward the evaporating portion 11 .

Further, as described above, since the lower liquid flow path recess 30 is formed so as to bulge from the lower recess opening 31 toward the bottom side, the cross-sectional shape of the lower liquid flow path recess 30 is It can be approximated to a perfect circular shape. For example, the lower liquid flow channel recess 30 according to the present embodiment can have a cross-sectional shape closer to a perfect circle than the forward tapered liquid flow channel recess 50 as shown in FIG. In this case, the flow path resistance that the liquid working fluid 2 passing through the lower liquid flow path concave portion 30 receives can be reduced, and the working fluid 2 can be smoothly transported toward the evaporating portion 11 .

The working fluid 2 that has reached the evaporator 11 receives heat from the device D again and evaporates. In this way, the working fluid 2 circulates in the vapor chamber 1 while repeating phase changes, that is, evaporation and condensation, thereby transferring heat from the device D and releasing it. As a result, the device D is cooled.

As described above, according to the present embodiment, the upper surface 13a of the lower flow path wall portion 13 of the lower metal sheet 10 is provided with the lower liquid flow path concave portion 30 through which the hydraulic fluid 2 passes. In the cross section of the passage recess 30 , the width w2 of the lower wide portion 32 of the lower liquid passage recess 30 is larger than the width w1 of the lower recess opening 31 . As a result, in the cross section of the lower liquid flow path recess 30, the length of the contour line of the lower liquid flow path recess 30 can be increased, and the capillary action can be increased. In addition, the cross-sectional shape of the lower liquid flow channel concave portion 30 can be made closer to a perfect circle, and the flow channel resistance can be reduced. Therefore, in the lower liquid flow path concave portion 30, the flow path resistance of the liquid working fluid 2 can be reduced and the capillary action can be enhanced. As a result, the liquid working fluid 2 can be smoothly transported toward the evaporating portion 11, promoting the heat transfer of the device D and improving the heat transport efficiency.

Further, according to the present embodiment, the cross section of the lower liquid flow path concave portion 30 is formed in an arc shape. As a result, the cross-sectional shape of the lower liquid flow path concave portion 30 can be made closer to a perfect circle, and the flow path resistance can be further reduced.

In the above-described first embodiment, an example in which the upper metal sheet 20 has the upper steam flow channel concave portion 21 has been described, but the upper metal sheet 20 is not limited to this. , may be formed in a flat plate shape as a whole and may not have the upper steam flow passage concave portion 21 . In this case, the mechanical strength of the vapor chamber 1 can be improved.

Various modifications can be made to the vapor chamber 1 according to the first embodiment described above.

(Modification 1)
In the present embodiment described above, an example in which the liquid flow path concave portion is not provided on the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20 has been described. However, it is not limited to this. For example, as shown in FIG. 16, the lower surface 22a of each upper flow path wall portion 22 may be provided with an upper liquid flow path recess 35 (second liquid flow path recess) through which the liquid working fluid 2 passes. FIG. 16 shows an example in which the upper liquid flow path recess 35 has the same shape as the lower liquid flow path recess 30 . That is, the upper liquid flow channel recess 35 communicates with the upper steam flow channel recess 21 and has a width smaller than the width of the upper flow channel wall 22 . The upper liquid flow path recess 35 includes an upper recess opening 36 (second recess opening) and an upper wide area located closer to the bottom side of the upper liquid flow path recess 35 (upper side in FIG. 16) than the upper recess opening 36. and a portion 37 (second large portion). In the cross section of the upper liquid flow path concave portion 35, the width w4 of the upper wide portion 37 is larger than the width w3 of the upper concave portion opening portion .

In particular, in Modification 1 shown in FIG. 16, the lower liquid flow path recess 30 and the upper liquid flow path recess 35 face each other. That is, the two liquid flow path recesses 30 and 35 facing each other communicate with each other to form one flow path. In this case, since the cross-sectional area of the flow path increases, the flow path resistance of the liquid working fluid 2 toward the evaporator 11 can be reduced. In addition, when the lower liquid flow path recess 30 and the upper liquid flow path recess 35 face each other, the cross-sectional shape of the flow path defined by these two liquid flow path recesses 30 and 35 is changed to a perfect circular shape. It can be brought closer and the flow path resistance can be further reduced. In addition, in order to make the cross-sectional shape of the flow path closer to a perfect circle, in the modification shown in FIG. 36 have the same width, and the lower liquid flow path recess 30 and the upper liquid flow path recess 35 are arranged so that both recess openings 31 and 36 overlap.

Note that the lower liquid flow path recess 30 and the upper liquid flow path recess 35 may be displaced in the horizontal direction in FIG. 16 and may not communicate with each other. Even in this case, the liquid working fluid 2 can pass through the upper liquid flow passage concave portion 35, so that the total flow passage cross-sectional area of the liquid working fluid 2 directed to the evaporation portion 11 is increased in the vapor chamber 1 as a whole. It is possible to reduce the flow path resistance of the liquid working fluid 2 toward the evaporator 11 .

(Modification 2)
Further, as shown in FIG. 17, on the lower surface 22a of the upper flow channel wall portion 22, an upper liquid flow channel having a cross-sectional shape different from that of the lower liquid flow channel concave portion 30 or the upper liquid flow channel concave portion 35 shown in FIG. A passage recess 55 may be provided. For example, as shown in FIG. 17, the upper liquid flow path recess 55 has an upper recess opening 56, but does not have portions corresponding to the large portions 32 and 37 shown in FIGS. First, in the cross section of the upper liquid flow channel recess 55, the width of the upper liquid flow channel recess 55 gradually decreases from the upper recess opening 56 toward the bottom side (upper side in FIG. 17) of the upper liquid flow channel recess 55. It may be. In this case, the width of the upper liquid flow path recess 55 is maximized at the upper recess opening 56, and the cross section of the upper liquid flow path recess 55 is formed in a forward tapered shape. In this case, the channel cross-sectional shape defined by the two liquid channel recesses 30 and 55 can be made closer to a perfect circle, and the channel resistance can be further reduced. In particular, in Modification 2 shown in FIG. 17, the cross section of the upper liquid flow path concave portion 55 is formed in a flat arc shape. In this case as well, the channel cross-sectional shape defined by the two liquid channel recesses 30 and 53 facing each other can be made closer to a perfect circle, and the channel resistance can be further reduced.

(Second embodiment)
Next, a vapor chamber and a vapor chamber metal sheet according to a second embodiment of the present invention will be described with reference to FIGS. 18 to 23. FIG.

In the second embodiment shown in FIGS. 18 to 23, the recessed liquid flow paths provided on the upper surface of the lower metal sheet and the recessed liquid flow paths provided on the lower surface of the upper metal sheet face each other. The main difference is that a part of the lower surface is exposed to the liquid flow path recess provided in the lower surface, or a part of the upper surface is exposed to the liquid flow path recess provided on the lower surface. , is substantially the same as the first embodiment shown in FIGS. 18 to 23, the same parts as those in the first embodiment shown in FIGS. 1 to 17 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the present embodiment, as shown in FIG. 18, the upper surface 13a of the lower flow path wall portion 13 of the lower metal sheet 10 has a lower liquid flow path concave portion 50 (first liquid channel recesses) are provided. On the other hand, the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20 is also provided with an upper liquid flow path recess 55 (second liquid flow path recess) through which the liquid working fluid 2 passes. Each of the liquid flow channel recesses 50 and 55 constitutes a part of the sealed space 3, but is different from the lower liquid flow channel recess 30 shown in FIG. 6 and the upper liquid flow channel recess 35 shown in FIG. They have different cross-sectional shapes.

18, the lower liquid flow path recess 50 has a lower recess opening 51 (first recess opening), which corresponds to the lower large portion 32 shown in FIG. does not have parts. In the cross section of the lower liquid flow path recess 50, the width of the lower liquid flow path recess 50 increases from the lower recess opening 51 toward the bottom side of the lower liquid flow path recess 50 (lower side in FIG. 18). gradually getting smaller. In this case, the width of the lower liquid flow channel recess 50 is maximized at the lower recess opening 51, and the cross section of the lower liquid flow channel recess 50 is formed in a forward tapered shape and in an arc shape. there is Here, an example is shown in which the cross section of the lower liquid flow path concave portion 50 is formed in a semicircular shape.

FIG. 18 shows an example in which the upper liquid flow path recess 55 has the same shape as the lower liquid flow path recess 50 . That is, the upper liquid flow path recess 55 has an upper recess opening 56 (second recess opening), but does not have a portion corresponding to the upper large portion 37 shown in FIG. In the cross section of the upper liquid flow channel recess 55, the width of the upper liquid flow channel recess 55 gradually decreases from the upper recess opening 56 toward the bottom side (upper side in FIG. 18) of the upper liquid flow channel recess 55. there is In this case, the width of the upper liquid flow path recess 55 is maximized at the upper recess opening 56, and the cross section of the upper liquid flow path recess 55 is tapered forward and arcuate. Here, an example is shown in which the cross section of the upper liquid flow path concave portion 55 is formed in a semicircular shape. The lower recess opening 51 of the lower liquid flow path recess 50 and the recess opening 52 of the upper liquid flow path recess 55 have the same width.

The lower liquid flow path recess 50 provided on the upper surface 13a of the lower flow path wall 13 and the upper liquid flow path recess 55 provided on the lower surface 22a of the upper flow path wall 22 face each other. That is, the two liquid flow path recesses 50 and 55 facing each other communicate with each other to form one flow path. In this case, since the cross-sectional area of the flow path increases, the flow path resistance of the liquid working fluid 2 toward the evaporator 11 can be reduced.

Further, in the present embodiment, part of the lower surface 22 a of the upper flow path wall portion 22 is exposed to the lower liquid flow path concave portion 50 . A portion of the upper surface 13 a of the lower flow path wall portion 13 is exposed to the upper liquid flow path concave portion 55 . In other words, the lower liquid flow path recess 50 and the upper liquid flow path recess 55 are shifted in the horizontal direction in FIG. In this case, the length of the contour line of one channel formed by the two liquid channel recesses 50 and 55 can be increased in the cross section. As a result, the capillary action that the liquid working fluid 2 passing through the liquid flow path recesses 50 and 55 receives can be increased.

As described above, according to the present embodiment, the lower liquid flow channel recessed portion 50 provided in the upper surface 13a of the lower flow channel wall portion 13 of the lower metal sheet 10 and the upper flow channel wall portion of the upper metal sheet 20 are arranged. 22 are opposed to each other, and a part of the lower surface 22a is exposed to the lower liquid flow path recess 50 . As a result, in cross section, the length of the contour line of one channel formed by the two liquid channel recesses 50 and 55 can be lengthened, and the capillary action can be increased. Moreover, the cross-sectional area of the channel can be increased, and the channel resistance can be reduced. Therefore, in the liquid flow path recesses 50 and 55, the flow path resistance of the liquid working fluid 2 can be reduced and the capillary action can be enhanced.

Further, according to the present embodiment, a portion of the upper surface 13 a of the lower flow path wall 13 of the lower metal sheet 10 is exposed to the upper liquid flow path recess 55 . As a result, in the cross section, the length of the contour line of one channel formed by the two liquid channel recesses 50 and 55 can be further increased, and the capillary action can be further increased. .

It should be noted that the vapor chamber 1 according to the second embodiment described above can be modified in various ways.

(Modification 3)
Further, in the present embodiment described above, an example has been described in which the two liquid flow path recesses 50 and 55 facing each other are formed in a forward tapered shape. However, the present invention is not limited to this, and at least one of the two liquid flow path recesses 50 and 55 facing each other may be formed in a reverse tapered shape. For example, as shown in FIG. 19, the cross-sectional shape of the lower liquid flow channel recess 50 is replaced with the cross-sectional shape of the reverse tapered lower liquid flow channel recess 30 shown in FIG. may be replaced with the cross-sectional shape of the reverse tapered upper liquid flow channel concave portion 35 shown in FIG. In FIG. 19, reference numeral 30 designates the first liquid flow channel recess provided on the upper surface 13a of the lower flow channel wall 13, and the second liquid flow channel recess provided on the lower surface 22a of the upper flow channel wall 22. is denoted by reference numeral 35. In modification 3 shown in FIG. 19, in the cross section, the length of the contour line of one channel formed by the two liquid channel recesses 30 and 35 can be further increased, and the capillary action can be further enhanced. can be increased.

(Modification 4)
In Modification 3 described above, the upper liquid flow path recess 35 may be formed in a forward tapered, flat arc shape as the upper liquid flow path recess 55 as shown in FIG. In this case also, in the cross section, the length of the contour line of one channel formed by the two liquid channel recesses 30 and 55 can be lengthened, and the capillary action can be increased.

(Modification 5)
In the present embodiment described above, the upper flow path wall portion 22 of the upper metal sheet 20 is positioned in the lower liquid flow path concave portion 50 provided in the upper surface 13 a of the lower flow path wall portion 13 of the lower metal sheet 10 . An example in which a portion of the lower surface 22a is exposed and a portion of the upper surface 13a is exposed to the upper liquid flow path concave portion 55 provided in the lower surface 22a has been described. However, the present invention is not limited to this. Although not shown, the upper surface 13a may not be exposed to the upper liquid flow path recess 55. Alternatively, as shown in FIG. The lower surface 22a does not have to be exposed. In Modified Example 5 shown in FIG. 21 , the width of the lower recess opening 51 of the lower liquid flow path recess 50 is smaller than the width of the upper recess opening 56 of the upper liquid flow path recess 55 . The radius of the lower liquid flow channel concave portion 50 formed in a semicircular cross section is smaller than the radius of the upper liquid flow channel concave portion 55 formed in a semicircular shape. The lower liquid flow path recess 50 and the upper liquid flow path recess 55 are arranged concentrically (so that their centers overlap in plan view). As a result, portions of the upper surface 13 a on both sides of the lower liquid flow path recess 50 are exposed to the upper liquid flow path recess 55 . Also in this case, in the cross section, the length of the contour line of one flow path formed by the two liquid flow path recesses 50 and 55 can be lengthened, and the capillary action can be increased.

(Modification 6)
Further, in the fifth modification described above, an example has been described in which the two liquid flow path recesses 50 and 55 facing each other are formed in a forward tapered shape. However, the present invention is not limited to this, and at least one of the two liquid flow path recesses 50 and 55 facing each other may be formed in a reverse tapered shape. For example, as shown in FIG. 22, the cross-sectional shape of the lower liquid flow channel recess 50 is replaced with the cross-sectional shape of the reverse tapered lower liquid flow channel recess 30 shown in FIG. may be replaced with the cross-sectional shape of the reverse tapered upper liquid flow channel concave portion 35 shown in FIG. In FIG. 22, reference numeral 30 designates the first liquid flow path recess provided on the upper surface 13a of the lower flow path wall 13, and the second liquid flow path recess provided on the lower surface 22a of the upper flow path wall 22. is denoted by reference numeral 35. In Modified Example 6 shown in FIG. 22 , the width of the lower recess opening 31 of the lower liquid flow path recess 30 is smaller than the width of the upper recess opening 36 of the upper liquid flow path recess 35 . As a result, portions of the upper surface 13 a on both sides of the lower liquid flow path recess 30 are exposed to the upper liquid flow path recess 35 . Therefore, in the cross section, the length of the contour line of one channel formed by the two liquid channel recesses 30 and 35 can be increased, and the capillary action can be increased.

(Modification 7)
In Modification 5 described above, the upper liquid flow path recess 35 may be formed in a forward tapered and flat circular arc shape as the upper liquid flow path recess 55 as shown in FIG. 23 . In this case also, in the cross section, the length of the contour line of one channel formed by the two liquid channel recesses 30 and 55 can be lengthened, and the capillary action can be increased.

The present invention is not limited to the above-described embodiments and modifications as they are, and can be embodied by modifying constituent elements without departing from the gist of the invention at the implementation stage. Also, various inventions can be formed by appropriate combinations of the plurality of constituent elements disclosed in the above embodiments and modifications. Some components may be deleted from all the components shown in the embodiment and modifications. Further, in each of the above-described embodiments and modifications, the configuration of the lower metal sheet 10 and the configuration of the upper metal sheet 20 may be interchanged.

1 vapor chamber 2 working fluid 3 sealed space 10 lower metal sheet 11 evaporator 12 lower steam channel recess 12a bottom surface 13 lower channel wall 13a upper surface 20 upper metal sheet 21 upper steam channel recess 21a ceiling surface 22 upper side Channel wall portion 22a Lower surface 30 Lower liquid channel recess 31 Lower recess opening 32 Lower large portion 35 Upper liquid channel recess 36 Upper recess opening 37 Upper large portion 50 Lower liquid channel recess 55 Upper liquid flow road recess

Claims (6)

A vapor chamber containing a hydraulic fluid,
a first metal sheet;
a second metal sheet provided on the first metal sheet;
Between the first metal sheet and the second metal sheet, a vapor channel through which the vapor of the working fluid passes and a liquid channel through which the liquid working fluid passes are provided,
The liquid flow path is provided in a first liquid flow path concave portion provided on the surface of the first metal sheet on the side of the second metal sheet and on the surface of the second metal sheet on the side of the first metal sheet. formed by facing and communicating with the second liquid flow path recessed part,
the cross-sectional shape of the first liquid flow path recess and the cross-sectional shape of the second liquid flow path recess are different from each other,
The first liquid flow path recess has a first recess opening, and the cross-sectional shape of the first liquid flow path recess extends from the first recess opening toward the bottom side of the first liquid flow path recess. It is arc-shaped with widening width,
The second liquid flow path recess has a second recess opening, and the cross-sectional shape of the second liquid flow path recess extends from the second recess opening toward the bottom side of the second liquid flow path recess. A vapor chamber that is arc-shaped with a narrowing width. 2. The vapor chamber according to claim 1, wherein the cross-sectional area of said first liquid flow path recess is greater than the cross-sectional area of said second liquid flow path recess. 3. The vapor chamber according to claim 2, wherein the cross-sectional shape of said second liquid flow path concave portion is a flat circular arc shape. 4. The vapor chamber according to any one of claims 1 to 3, wherein the first liquid flow path recess and the second liquid flow path recess are offset from each other in the width direction. 5. The vapor chamber according to any one of claims 1 to 4, wherein the widthwise length of the first recessed opening and the widthwise length of the second recessed opening are different from each other. A mobile terminal comprising a vapor chamber according to any one of claims 1-5.

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