JP7552744B2 - Vapor chamber, sheet for vapor chamber, and method for manufacturing vapor chamber - Google Patents

Description

The present disclosure relates to a vapor chamber having a sealed space in which a working fluid is sealed, a sheet for a vapor chamber, and a method for manufacturing a vapor chamber.

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, there has been a demand for thinner heat dissipation members in order to make mobile terminals thinner, and vapor chambers that can be made thinner than heat pipes have been developed. Vapor chambers have a structure in which two sheets are joined together, and a sealed space filled with a working fluid is formed between the two sheets. This 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 in the part close to the device (evaporation part) and evaporates from liquid to gas, and the gas then moves to a position away from the evaporation part where it is cooled and condenses to liquid. A liquid flow path is provided in the vapor chamber as a capillary structure (wick), and the liquid working fluid passes through this liquid flow path and is transported toward the evaporation part, 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 heat transport efficiency.

JP 2015-121355 A

The present disclosure aims to provide a vapor chamber, a sheet for a vapor chamber, and a method for manufacturing a vapor chamber that can improve heat transport efficiency.

This application discloses a vapor chamber having a sealed space in which a working fluid is sealed, the sealed space being provided with a plurality of vapor flow paths through which the working fluid in a gaseous state flows, and a wick material provided between the plurality of adjacent vapor flow paths through which the working fluid in a liquid state flows, at least one of a recess and a protrusion is provided on at least a portion of the outer surface of the vapor chamber at a position overlapping the vapor flow path in a plan view, and the recess and protrusion have a curved shape in a cross section perpendicular to the direction in which the vapor flow path extends.

The present application also discloses a vapor chamber having a sealed space filled with a working fluid, the sealed space being provided with a plurality of vapor flow paths through which the working fluid in a gaseous state flows, and a liquid flow path or wick material provided between adjacent vapor flow paths through which the working fluid in a liquid state flows, and a recess is provided on at least a portion of the outer surface of the vapor chamber at a position overlapping the vapor flow path in a plan view, and the recess is provided across the entire width of the vapor flow path in a cross section perpendicular to the direction in which the vapor flow path extends.

The present application also discloses a vapor chamber having a sealed space in which a working fluid is sealed, the sealed space being provided with a plurality of vapor flow paths through which the working fluid in a gaseous state flows, and a liquid flow path or wick material provided between adjacent vapor flow paths through which the working fluid in a liquid state flows, and a recess is provided on at least a portion of the outer surface of the vapor chamber at a position overlapping the vapor flow path in a plan view, and the recess is not provided at a position overlapping the liquid flow path or wick material in a plan view.

According to the present disclosure, it is possible to improve the heat transport efficiency.

FIG. 1 is a perspective view showing a schematic diagram of an electronic device equipped with a vapor chamber. FIG. 2 is a top view of a vapor chamber according to an embodiment of the present disclosure. FIG. 3 is a cross-sectional view of the vapor chamber taken along line AA of FIG. FIG. 4 is a plan view of the lower sheet of FIG. FIG. 5 is a bottom view of the upper sheet of FIG. FIG. 6 is an enlarged cross-sectional view showing the steam flow passage recess shown in FIG. FIG. 7 is an enlarged top view of part B showing the liquid flow path portion in FIG. FIG. 8 is an enlarged cross-sectional view showing the liquid flow path portion of FIG. FIG. 9 is a cross-sectional view showing an example in which the upper sheet is also provided with main grooves. FIG. 10 is a diagram for explaining a first preparation step of the lower material sheet in the manufacturing method of the vapor chamber in FIG. FIG. 11 is a diagram for explaining a step of forming a lower flow passage groove in a lower material sheet in the manufacturing method of the vapor chamber in FIG. FIG. 12 is a diagram for explaining a second preparation step of the upper material sheet in the manufacturing method of the vapor chamber in FIG. FIG. 13 is a diagram for explaining a step of forming upper flow passage grooves in an upper material sheet in the manufacturing method of the vapor chamber in FIG. FIG. 14 is a diagram for explaining a temporary fixing step in the manufacturing method of the vapor chamber in FIG. FIG. 15 is a diagram for explaining a bonding step in the manufacturing method of the vapor chamber of FIG. FIG. 16 is a diagram showing the steam flow passage recess after bonding in the bonding step of FIG. FIG. 17 is a diagram for explaining the step of injecting the working liquid in the method for manufacturing the vapor chamber of FIG. FIG. 18 is a partially enlarged cross-sectional view showing a state in which the lower sheet is pressed in the vapor chamber in the modified example. FIG. 19 is a partially enlarged cross-sectional view showing a state in which an upper sheet is pressed in a vapor chamber in a modified example. FIG. 20 is an enlarged cross-sectional view showing a vapor chamber in a modified example. FIG. 21 is an enlarged cross-sectional view showing a modification of the vapor chamber shown in FIG. FIG. 22 is an enlarged cross-sectional view showing a modification of the vapor chamber shown in FIG. FIG. 23 is an enlarged cross-sectional view showing a vapor chamber made of three sheets. FIG. 24 is an enlarged cross-sectional view of another example of a three-sheet vapor chamber. FIG. 25 is an enlarged cross-sectional view showing a vapor chamber made of four sheets. FIG. 26 is an enlarged cross-sectional view showing an example of a vapor chamber having a protrusion.

Hereinafter, the present disclosure will be described with reference to the drawings. In the drawings attached to this specification, the scale and aspect ratios may be appropriately changed and exaggerated from those of the actual objects for the convenience of illustration and understanding.
In addition, in a vapor chamber, the working fluid moves within the sealed space while undergoing a phase change, so in this specification, the working fluid that has evaporated into a gas state may be referred to as "vapor" and the working fluid that has liquefied into a liquid state may be referred to as "working liquid."

First, the electronic device E equipped with the vapor chamber 1 according to this embodiment will be described using a tablet terminal as an example. As shown in FIG. 1, the electronic device E (tablet terminal) includes a housing H, a device D housed 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 housed 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 in use. The heat received by the vapor chamber 1 is released to the outside of the vapor chamber 1 via the working fluid described later. In this way, the device D is cooled. When the electronic device E is a tablet terminal, the device D corresponds to a central processing unit or the like.

The vapor chamber, vapor chamber sheet, and vapor chamber manufacturing method according to the embodiment of the present disclosure will be described with reference to Figures 2 to 21. The vapor chamber 1 in this embodiment has a sealed space 3 filled with a working fluid 2 (see Figure 6), and is a device for cooling a heat-generating device D (cooled device) such as a central processing unit (CPU), light-emitting diode (LED), or power semiconductor used in mobile devices such as mobile terminals and tablet terminals by repeatedly changing phases of the working fluid in the sealed space 3. The vapor chamber 1 is generally formed in a thin, flat plate shape.

2 and 3, the vapor chamber 1 of this embodiment includes a lower sheet 10 (first sheet, vapor chamber sheet) and an upper sheet 20 (second sheet, vapor chamber sheet) provided on the lower sheet 10. The lower sheet 10 has an upper surface 10a (first sheet surface) and a lower surface 10b (first opposite surface) opposite the upper surface 10a. A device D, which is an object to be cooled, is attached to the lower surface 10b (particularly the lower surface of the evaporator 11 described later). The upper sheet 20 has a lower surface 20a (second sheet surface) and an upper surface 20b (second opposite surface) provided opposite the lower surface 20a. The lower surface 20a is superimposed on the upper surface 10a of the lower sheet 10, and the lower sheet 10 and the upper sheet 20 are joined by diffusion bonding described later.

A sealed space 3 containing a working fluid is formed between the lower sheet 10 and the upper sheet 20. Examples of working fluids include pure water, ethanol, methanol, acetone, and mixtures thereof.

2 and 3, the lower sheet 10 and the upper sheet 20 are each formed to have a rectangular shape in plan view, but are not limited thereto. In addition to being rectangular as in this embodiment, the lower sheet 10 and the upper sheet 20 may be formed to have a circular, elliptical, triangular, or other polygonal shape in plan view, a shape having a bent portion, such as an L-shape, a T-shape, or a crank shape, or a shape that is a combination of these.
Here, a planar view refers to a state in which the vapor chamber 1 is viewed from the normal direction of the surface that receives heat from the device D (the lower surface 10b of the lower sheet 10) and the surface that releases the received heat (the upper surface 20b of the upper sheet 20), and corresponds to, for example, the state in which the vapor chamber 1 is viewed from above (see Figure 2) or from below.

Note that, although the first sheet is described as the lower sheet and the second sheet as the upper sheet, this does not necessarily limit the hierarchical relationship, but is described for convenience. Here, the sheet that receives heat from device D is the first sheet, and the sheet placed on the opposite side is the second sheet. The descriptions "upper" and "lower" given to other parts are simply to conform to this description.

As shown in Figures 3 and 4, the lower sheet 10 has an evaporation section 11 where the working fluid 2 evaporates to generate steam, and a lower steam flow path recess 12 (first steam flow path recess) that is provided on the upper surface 10a and has a rectangular shape in a plan view. Of these, the lower steam flow path recess 12 constitutes a part of the above-mentioned sealed space 3, and is configured mainly to allow the steam generated in the evaporation section 11 to pass through.

In this embodiment, the lower steam passage recess 12 has a plurality of lower passage grooves (i.e., a plurality of first lower passage grooves 12G1, a plurality of second lower passage grooves 12G2, and a plurality of third lower passage grooves 12G3). Each of the first lower passage grooves 12G1 and the second lower passage grooves 12G2 extends in a first direction X to allow a working fluid containing a large amount of steam to pass therethrough, and is arranged at different positions with intervals in a second direction Y perpendicular to the first direction X.
On the other hand, the third lower passage groove 12G3 extends in the second direction Y and is connected to both end portions of the first lower passage groove 12G1 and the second lower passage groove 12G2. In this embodiment, each of the lower passage grooves 12G1, 12G2, and 12G3 has a curved portion in cross section. A bottom surface 12a, which will be described later, corresponds to a portion of the wall surface of the lower steam passage recess 12 on the side of the lower surface 10b of the lower sheet 10.

The evaporation section 11 is disposed in this lower steam flow path recess 12, and the first lower flow path groove 12G1 overlaps the evaporation section 11 in a plan view. The steam in the lower steam flow path recess 12 diffuses in a direction away from the evaporation section 11, and most of the steam is transported toward the peripheral portion, which has a relatively low temperature.

The evaporation section 11 is a section where the working liquid 2 in the sealed space 3 evaporates upon receiving heat from the device D attached to the lower surface 10b of the lower sheet 10. For this reason, the term evaporation section 11 is used not only to refer to the section that overlaps the device D in a plan view of the vapor chamber, but also to a section where the working liquid 2 can evaporate even if it does not overlap the device D. The evaporation section 11 can be provided anywhere on the lower sheet 10, but FIGS. 2 and 4 show an example where it is provided in the center of the lower sheet 10. In this case, it is possible to prevent the attitude of the mobile terminal on which the vapor chamber 1 is installed from affecting the stabilization of the operation of the vapor chamber 1.

In this embodiment, as shown in Figures 3, 4, and 6, a plurality of lower flow path walls 13 (first flow path walls) are provided in the lower steam flow path recess 12, protruding upward (perpendicular to the upper surface 10a) from the bottom surface 12a of the lower steam flow path recess 12. The lower flow path walls 13 include upper surfaces 13a (protruding end surfaces) that contact the lower surfaces 22a of the upper flow path walls 22 described below.

In this embodiment, the lower flow passage wall 13 is elongated along the direction (X direction) in which the first lower flow passage groove 12G1 and the second lower flow passage groove 12G2 of the vapor chamber 1 extend. The lower flow passage walls 13 are arranged parallel to each other at equal intervals. The lower flow passage wall 13 divides the lower steam flow passage recess 12 into the first lower flow passage groove 12G1 and the second lower flow passage groove 12G2 described above. That is, the first lower flow passage groove 12G1 is formed between the adjacent lower flow passage walls 13. Similarly, the second lower flow passage groove 12G2 is formed between a lower peripheral wall 14 described later and the lower flow passage wall 13 adjacent thereto in the second direction Y.
In this manner, the steam flows around each lower flow passage wall portion 13, and is transported away from the evaporation portion 11, thereby preventing the flow of the steam from being impeded. For example, in the first lower flow passage groove 12G1, the steam is transported toward the third lower flow passage groove 12G3.

In addition, the lower flow passage wall portion 13 is arranged so as to overlap the corresponding upper flow passage wall portion 22 (described later) of the upper sheet 20 in a plan view, thereby improving the mechanical strength of the vapor chamber 1.
The width w0 of the lower flow path wall 13 shown in FIG. 6 and FIG. 7 is preferably 3000 μm or less on the upper surface 10a, may be 1500 μm or less, or may be 1000 μm or less. On the other hand, the width w0 is preferably 100 μm or more on the upper surface 10a, may be 200 μm or more, or may be 400 μm or more. The range of the width w0 may be determined by a combination of any one of the multiple upper limit candidate values and one of the multiple lower limit candidate values. The range of the width w0 may be determined by a combination of any two of the multiple upper limit candidate values, or a combination of any two of the multiple lower limit candidate values. Here, the width w0 means the dimension of the lower flow path wall 13 in a direction (Y direction) perpendicular to the longitudinal direction (X direction) of the lower flow path wall 13, and corresponds to, for example, the vertical dimension in FIG. 4 and FIG. 7, or the horizontal dimension in FIG. 6.
The width w1 of the first lower flow channel groove 12G1 (the distance between the adjacent lower flow channel walls 13) is preferably 2000 μm or less on the upper surface 10a, and may be 1500 μm or less, or may be 1000 μm or less. On the other hand, the width w1 is preferably 100 μm or more on the upper surface 10a, and may be 200 μm or more, or may be 400 μm or more. The range of the width w1 may be determined by a combination of any one of the multiple upper limit candidate values and one of the multiple lower limit candidate values. The range of the width w1 may be determined by a combination of any two of the multiple upper limit candidate values, or a combination of any two of the multiple lower limit candidate values.
The width of the second lower passage groove 12G2 and the width of the third lower passage groove 12G3 may be equal to the width of the first lower passage groove 12G1.

The height h0 of the lower flow passage wall 13 shown in FIG. 6 (in other words, the depth of the lower steam flow passage recess 12) is preferably 300 μm or less, and may be 200 μm or less, or 100 μm or less. On the other hand, the height h0 is preferably 10 μm or more, and may be 25 μm or more, or 50 μm or more. The range of the height h0 may be determined by a combination of any one of the multiple upper limit candidate values and one of the multiple lower limit candidate values. The range of the height h0 may be determined by a combination of any two of the multiple upper limit candidate values, or a combination of any two of the multiple lower limit candidate values.

As shown in Figures 3 and 4, a lower peripheral wall 14 is provided on the peripheral portion of the lower sheet 10. The lower peripheral wall 14 is formed to surround the sealed space 3, particularly the lower steam flow path recess 12, and defines the sealed space 3. In addition, lower alignment holes 15 are provided at the four corners of the lower peripheral wall 14 in a plan view to position the lower sheet 10 and the upper sheet 20.

As shown in FIG. 6, the lower surface 10b of the lower sheet 10 has a lower sheet recess 50 (first sheet recess) recessed toward the lower steam flow path recess 12. The lower sheet recess 50 is disposed at a position on the lower surface 10b that overlaps with the lower steam flow path recess 12 in a plan view. FIG. 6 shows an example in which the cross-sectional shape of the lower sheet recess 50 has a curved portion, but this is not limited thereto and the shape may be a rectangle, a V-shape, or a combination of these.

In this embodiment, as described above, a plurality of lower flow passage walls 13 are provided in the lower steam flow passage recess 12, and the first lower flow passage groove 12G1, the second lower flow passage groove 12G2, and the third lower flow passage groove 12G3 defined by the lower flow passage walls 13 are formed. As a result, the lower sheet recess 50 is disposed between a pair of adjacent lower flow passage walls 13 (at a position overlapping the first lower flow passage groove 12G1). The lower sheet recess 50 overlapping the first lower flow passage groove 12G1 extends continuously in an elongated manner along the first direction X so as to follow the first lower flow passage groove 12G1 in a plan view. The lower sheet recess 50 may also be formed between the lower peripheral wall 14 and the lower flow passage wall 13 adjacent thereto (at a position overlapping the second lower flow passage groove 12G2). The lower sheet recess 50 overlapping the second lower flow groove 12G2 extends continuously in an elongated shape along the first direction X so as to follow the second lower flow groove 12G2. Furthermore, a lower sheet recess 50 may also be formed at a position overlapping the third lower flow groove 12G3 in a plan view, and the lower sheet recess 50 extends continuously in an elongated shape along the second direction Y so as to follow the third lower flow groove 12G3.

As shown in FIG. 6, a lower bottom surface convex portion 51 (first bottom surface convex portion) that protrudes inward of the lower steam flow path concave portion 12 is provided at a position on the bottom surface 12a that defines the lower steam flow path concave portion 12 that overlaps with the lower sheet concave portion 50 in a plan view. In FIG. 6, an example is shown in which the cross-sectional shape of the lower bottom surface convex portion 51 is curved in the same shape as the lower sheet concave portion 50, but this is not limited to this, and the shape may be a rectangle, a V-shape, or a combination of these.

In a plan view, the lower bottom surface convex portion 51 is disposed between a pair of adjacent lower flow path walls 13 (at a position overlapping the first lower flow path groove 12G1) in the same manner as the lower sheet recessed portion 50. The lower bottom surface convex portion 51 overlapping the first lower flow path groove 12G1 extends continuously in an elongated manner along the first direction X so as to follow the first lower flow path groove 12G1. The lower bottom surface convex portion 51 may also be formed between the lower peripheral wall 14 and the adjacent lower flow path wall 13 (at a position overlapping the second lower flow path groove 12G2). The lower bottom surface convex portion 51 overlapping the second lower flow path groove 12G2 extends continuously in an elongated manner along the first direction X so as to follow the second lower flow path groove 12G2. Furthermore, a lower bottom surface protrusion 51 may be formed at a position overlapping with the third lower flow channel 12G3 in a plan view, and the lower bottom surface protrusion 51 extends continuously in an elongated manner along the second direction Y so as to follow the third lower flow channel 12G3. That is, in this embodiment, the lower bottom surface protrusion 51 is formed in conjunction with the formation of the lower sheet recess 50 as described below, and is therefore formed in the same position as the lower sheet recess 50 in a plan view and with a similar cross-sectional shape. Note that, by having each lower bottom surface protrusion 51 extend continuously in an elongated manner as described above, the flow of steam in each of the lower flow channel 12G1 to 12G3 is prevented from being impeded.

As shown in FIG. 6, the thickness t3 of the portion between the lower surface 10b of the lower sheet 10, where the lower recess 50 is formed, and the first lower flow channel 12G1 is smaller than the thickness t4 of the portion between the lower surface 10b and the main flow channel 31, which will be described later. In other words, t3 is thinner than t4.

In this embodiment, the upper sheet 20 has substantially the same structure as the lower sheet 10, except that the upper sheet 20 does not have a liquid flow path section 30, which will be described later. The structure of the upper sheet 20 will be described in more detail below.

As shown in Figures 3 and 5, the upper sheet 20 has an upper steam flow path recess 21 (second steam flow path recess) provided on the lower surface 20a. This upper steam flow path recess 21 constitutes a part of the sealed space 3, and is configured mainly to allow the steam generated in the evaporation section 11 to pass through and cool the steam. The upper steam flow path recess 21 is formed so as to overlap with the lower steam flow path recess 12 in a plan view. The depth of the upper steam flow path recess 21 may be the same as the depth h0 of the lower steam flow path recess 12.

In this embodiment, the upper steam flow passage recess 21 has a plurality of upper flow passage grooves (i.e., a plurality of first upper flow passage grooves 21G1, a plurality of second upper flow passage grooves 21G2, and a plurality of third upper flow passage grooves 21G3). Each of the first upper flow passage grooves 21G1 and the second upper flow passage grooves 21G2 extends in the first direction X to allow steam to pass through, and is arranged at different positions with intervals in the second direction Y perpendicular to the first direction X. The third upper flow passage groove 21G3 extends in the second direction Y and communicates with both ends of the first upper flow passage groove 21G1 and the second upper flow passage groove 21G2. In this embodiment, each of the upper flow passage grooves 21G1, 21G2, and 21G3 is formed to have a curved portion in the cross section. The bottom surface 21a described later corresponds to the portion of the wall surface of the upper steam flow passage recess 21 on the side of the upper surface 20b of the upper sheet 20.

The steam in the upper steam flow passage recess 21 diffuses away from the evaporation section 11, and most of it is transported toward the peripheral area, which has a relatively low temperature.

As shown in FIG. 3, a housing member H that constitutes part of the housing of a mobile terminal or the like is disposed on the upper surface 20b of the upper sheet 20. As a result, the steam in the upper steam flow passage recess 21 is cooled by the outside via the upper sheet 20 and the housing member H.

In this embodiment, as shown in Figs. 2, 5 and 6, a plurality of upper flow path walls 22 (second flow path walls) are provided in the upper steam flow path recess 21 of the upper sheet 20, protruding downward (perpendicular to the lower surface 20a) from the bottom surface 21a of the upper steam flow path recess 21. The upper flow path walls 22 include a lower surface 22a (protruding end surface) that contacts the upper surface 13a of the lower flow path wall 13 described above. Here, the bottom surface 21a of the upper steam flow path recess 21 can be called a ceiling surface in the vertical arrangement relationship between the lower sheet 10 and the upper sheet 20 as shown in Fig. 3, etc., but since it corresponds to the innermost surface of the upper steam flow path recess 21, it is referred to as the bottom surface 21a in this specification.

In this embodiment, the upper flow passage wall 22 is shown as being elongated and extending along the first upper flow passage groove 21G1 and the second upper flow passage groove 21G2 (in the left-right direction in FIG. 5). The upper flow passage walls 22 are arranged parallel to each other at equal intervals. The upper steam flow passage recess 21 is divided into the first upper flow passage groove 21G1 and the second upper flow passage groove 21G2 by the upper flow passage wall 22. That is, the first upper flow passage groove 21G1 is formed between a pair of adjacent upper flow passage walls 22. Similarly, the second upper flow passage groove 21G2 is formed between the upper peripheral wall 23 described later and the upper flow passage wall 22 adjacent thereto. In this way, the steam flows around each upper flow passage wall 22 and is transported toward the peripheral portion of the upper steam flow passage recess 21, suppressing the flow of steam from being impeded. For example, in the first upper flow channel 21G1, steam is transported toward the third upper flow channel 21G3.

The upper flow passage wall 22 is arranged so as to overlap the corresponding lower flow passage wall 13 of the lower sheet 10 in a plan view, improving the mechanical strength of the vapor chamber 1. Note that, although an example is shown in Figs. 2, 3, and 6 in which the width and height of the upper flow passage wall 22 are the same as the width w0 and height h0 of the lower flow passage wall 13 described above, they do not have to be the same. In addition, the width of the first upper flow passage groove 21G1 may be equal to the width of the first lower flow passage groove 12G1, or may be larger or smaller than the width of the second upper flow passage groove 21G2, or may be equal to the width of the second lower flow passage groove 12G2, or may be larger or smaller than the width of the third upper flow passage groove 21G3.

As shown in Figures 3 and 5, an upper peripheral wall 23 is provided on the peripheral portion of the upper sheet 20. The upper peripheral wall 23 is formed to surround the sealed space 3, particularly the upper steam flow path recess 21, and defines the sealed space 3. In addition, upper alignment holes 24 for positioning the lower sheet 10 and the upper sheet 20 are provided at the four corners of the upper peripheral wall 23 in a plan view. That is, each upper alignment hole 24 is arranged to overlap with each lower alignment hole 15 described above when temporarily fastening as described below, and is configured to enable positioning of the lower sheet 10 and the upper sheet 20.

As shown in FIG. 6, an upper sheet recess 60 (second sheet recess) recessed toward the upper steam flow path recess 21 is provided on the upper surface 20b of the upper sheet 20. This upper sheet recess 60 is disposed at a position on the upper surface 20b that overlaps with the upper steam flow path recess 21 in a plan view. FIG. 6 shows an example in which the cross-sectional shape of the upper sheet recess 60 has a curved portion, but this is not limited thereto and the upper sheet recess 60 may be rectangular, V-shaped, or a combination of these.

In this embodiment, as described above, a plurality of upper flow passage walls 22 are provided in the upper steam flow passage recess 21, and the first upper flow passage groove 21G1, the second upper flow passage groove 21G2, and the third upper flow passage groove 21G3 defined by the upper flow passage walls 22 are formed. As a result, the upper sheet recess 60 is disposed between a pair of adjacent upper flow passage walls 22 (at a position overlapping the first upper flow passage groove 21G1). The upper sheet recess 60 overlapping the first upper flow passage groove 21G1 extends continuously in an elongated manner along the first direction X so as to follow the first upper flow passage groove 21G1 in a plan view. The upper sheet recess 60 may also be formed between the upper peripheral wall 23 and the adjacent upper flow passage wall 22 (at a position overlapping the second upper flow passage groove 21G2). The upper sheet recess 60 that overlaps with the second upper flow channel 21G2 extends continuously in an elongated shape along the first direction X so as to follow the second upper flow channel 21G2. Furthermore, an upper sheet recess 60 may also be formed at a position that overlaps with the third upper flow channel 21G3 in a plan view, and the upper sheet recess 60 extends continuously in an elongated shape along the second direction Y so as to follow the third upper flow channel 21G3.

As shown in FIG. 6, an upper bottom surface convex portion 61 (second bottom surface convex portion) that protrudes inward of the upper steam flow path concave portion 21 is provided at a position on the bottom surface 21a that defines the upper steam flow path concave portion 21 that overlaps with the upper sheet concave portion 60 in a plan view. In FIG. 6, an example is shown in which the cross-sectional shape of the upper bottom surface convex portion 61 has a curved portion in a shape similar to that of the upper sheet concave portion 60, but this is not limited to this, and the shape may be a rectangle, a V-shape, or a combination of these.

In a plan view, the upper bottom surface convex portion 61 is disposed between a pair of adjacent upper flow path walls 22 (at a position overlapping the first upper flow path groove 21G1) in the same manner as the upper sheet recess 60. The upper bottom surface convex portion 61 overlapping the first upper flow path groove 21G1 extends continuously in an elongated manner along the first direction X so as to follow the first upper flow path groove 21G1. The upper bottom surface convex portion 61 may also be formed between the upper peripheral wall 23 and the adjacent upper flow path wall portion 22 (at a position overlapping the second upper flow path groove 21G2). The upper bottom surface convex portion 61 overlapping the second upper flow path groove 21G2 extends continuously in an elongated manner along the first direction X so as to follow the second upper flow path groove 21G2. Furthermore, an upper bottom surface protrusion 61 may be formed at a position overlapping with the third upper flow passage groove 21G3 in a plan view, and the upper bottom surface protrusion 61 extends continuously in an elongated manner along the second direction Y so as to follow the third upper flow passage groove 21G3. That is, in this embodiment, the upper bottom surface protrusion 61 is formed in conjunction with the formation of the upper sheet recess 60 as described below, and is therefore formed in the same position as the planar position of the upper sheet recess 60 and with the same cross-sectional shape. Note that, by each upper bottom surface protrusion 61 extending continuously in an elongated manner as described above, the flow of steam in each of the upper flow passage grooves 21G1 to 21G3 is prevented from being impeded.

In FIG. 6, the thickness t5 of the portion between the upper surface 20b of the upper sheet 20 and the upper steam flow path recess 21 is equal to the above-mentioned thickness t3 of the lower sheet 10. However, this thickness t5 may be different from the thickness t3.

Such a lower sheet 10 and an upper sheet 20 are permanently bonded to each other, preferably by diffusion bonding. More specifically, as shown in FIG. 3, the upper surface 14a of the lower peripheral wall 14 of the lower sheet 10 and the lower surface 23a of the upper peripheral wall 23 of the upper sheet 20 are in contact with each other, and the lower peripheral wall 14 and the upper peripheral wall 23 are bonded to each other. As a result, a sealed space 3 that seals the working fluid is formed between the lower sheet 10 and the upper sheet 20. In addition, the upper surface 13a of the lower flow path wall 13 of the lower sheet 10 and the lower surface 22a of the upper flow path wall 22 of the upper sheet 20 are in contact with each other, and each lower flow path wall 13 and the corresponding upper flow path wall 22 are bonded to each other. This improves the mechanical strength of the vapor chamber 1. When the lower flow path wall 13 and the upper flow path wall 22 according to this embodiment are arranged at equal intervals, the mechanical strength at each position of the vapor chamber 1 can be made close to uniform. The lower sheet 10 and the upper sheet 20 may be joined by other methods such as brazing, instead of diffusion bonding, as long as they can be permanently joined. Here, "permanently joined" is not limited to a strict meaning, but means that they are joined to the extent that the bond between the upper surface 10a of the lower sheet 10 and the lower surface 20a of the upper sheet 20 can be maintained to the extent that the sealability of the sealed space 3 can be maintained when the vapor chamber 1 is in operation.

2, the vapor chamber 1 further includes an injection section 4 at one end of a pair of longitudinal ends for injecting the working fluid into the sealed space 3. As shown in FIGS. 4 and 5, the injection section 4 has a lower injection protrusion 16 protruding from the end face of the lower sheet 10 and an upper injection protrusion 25 protruding from the end face of the upper sheet 20. A lower injection flow path recess 17 is formed on the upper surface of the lower injection protrusion 16, and an upper injection flow path recess 26 is formed on the lower surface of the upper injection protrusion 25. The lower injection flow path recess 17 is connected to the lower steam flow path recess 12 (more specifically, one of the third lower flow path grooves 12G3), and the upper injection flow path recess 26 is connected to the upper steam flow path recess 21 (more specifically, one of the third upper flow path grooves 21G3). The lower injection flow channel recess 17 and the upper injection flow channel recess 26 form an injection flow channel for the working fluid when the lower sheet 10 and the upper sheet 20 are joined. The working fluid is injected into the sealed space 3 through the injection flow channel. In this embodiment, the injection part 4 is provided at one end of a pair of ends in the longitudinal direction of the vapor chamber 1, but this is not limited to this example and may be located at any other end, or multiple injection parts may be provided. When multiple injection parts are provided, they may be located at each of a pair of ends in the longitudinal direction of the vapor chamber 1, or at one end of the other pair of ends.

As shown in Figs. 4, 7 and 8, a lower liquid flow path section 30 through which the working fluid 2 passes is provided on the upper surface 13a of each lower flow path wall section 13. The lower liquid flow path section 30 constitutes a part of the above-mentioned sealed space 3, and is connected to the above-mentioned lower steam flow path recess 12 and upper steam flow path recess 21.

The lower liquid flow path section 30 has a plurality of mainstream grooves 31. Each mainstream groove 31 extends in a first direction X along the extension direction of the lower flow path wall section 13 so that the working fluid 2 passes through it, and is arranged at different positions and intervals in a second direction Y perpendicular to the first direction X. The mainstream grooves 31 are mainly configured to transport the working fluid 2 condensed from the steam generated in the evaporation section 11 toward the evaporation section 11.

In this embodiment, the main flow groove 31 is shown as an example extending in an elongated manner along the longitudinal direction (first direction X) of the lower flow path wall 13, and extends from one end to the other end in the longitudinal direction of the lower flow path wall 13. Each main flow groove 31 communicates with the third lower flow path groove 12G3 of the lower steam flow path recess 12. In this manner, the working fluid 2 condensed at the periphery of the lower steam flow path recess 12 and the periphery of the upper steam flow path recess 21 is transported toward the evaporation section 11 by capillary action. A plurality of main flow path grooves 31 are formed on the upper surface 13a of one lower flow path wall 13, and the main flow path grooves 31 are arranged parallel to each other at equal intervals. In this embodiment, an example is shown in which the cross section of the main flow path groove 31 is generally curved, but the cross section of the main flow path groove 31 may have any shape as long as it can produce capillary action. Therefore, the cross-sectional shape of the groove may have an inside corner, an outside corner, or a combination of these.
In this embodiment, the main flow grooves 31 are arranged parallel to each other at equal intervals, but this is not limited to this, and the intervals may vary and the grooves do not have to be parallel as long as the capillary action can be achieved. Furthermore, the number of main flow grooves 31 in each lower flow passage wall portion 13 may vary, and there may be a portion of the lower flow passage wall portion 13 where there is no main flow groove 31.

Although not shown, a plurality of communication grooves (not shown) extending in a direction crossing the mainstream grooves 31 (e.g., the second direction Y) may be provided, and these communication grooves may connect the mainstream grooves 31 to each other and also connect the mainstream grooves 31 to the lower steam flow path recess 12.
Alternatively, in the evaporation section 11, the lower surface 22a of the upper flow passage wall section 22 may be separated from the upper surface 13a of the lower flow passage wall section 13 to provide a gap. In this case, the space between the upper surface 13a and the lower surface 22a communicates with the lower steam flow passage recess 12 and the upper steam flow passage recess 21, so that each mainstream groove 31 can communicate with each steam flow passage recess 12, 21.

On the upper surface 10a of the lower sheet 10, the width w2 of the mainstream groove 31 shown in Fig. 8 is smaller than the width w0 of the lower flow path wall portion 13 shown in Fig. 7. As a result, the mainstream groove 31 is filled with the working fluid 2 condensed from vapor, and the filled liquid working fluid 2 is transported toward the evaporation portion 11 by capillary action. On the other hand, each of the lower flow path grooves 12G1, 12G2, 12G3 and each of the upper flow path grooves 21G1, 21G2, 21G3 has a flow path cross-sectional area larger than the flow path cross-sectional area of the mainstream groove 31, and mainly the vapor generated in the evaporation portion 11 passes through them.
More specifically, when the flow passage formed by each of the lower flow passage grooves 12G1, 12G2, 12G3 and each of the upper flow passage grooves 21G1, 21G2, 21G3 and through which mainly the steam passes is defined as the first flow passage, and the flow passage formed by the main flow passage groove 31 and through which mainly the working fluid passes is defined as the second flow passage, the flow passage cross-sectional area of the second flow passage is smaller than the flow passage cross-sectional area of the first flow passage. More specifically, when the average flow passage cross-sectional area of two adjacent first flow passages is Ag and the average flow passage cross-sectional area of the multiple second flow passages arranged between the two adjacent first flow passages is Al, the second flow passages and the first flow passages are in a relationship in which Al is 0.5 times or less than Ag, and preferably 0.25 times or less. It is sufficient that this relationship is satisfied in at least a part of the entire vapor chamber, and it is more preferable that this relationship is satisfied in the entire vapor chamber.

The width w2 of the main groove 31 means the dimension of the main groove 31 in a direction perpendicular to the longitudinal direction of the main groove 31, and corresponds to, for example, the dimension in the up-down direction in FIG. 7 or the dimension in the left-right direction in FIG.
The width w2 is preferably 1000 μm or less, may be 500 μm or less, or may be 200 μm or less. On the other hand, the width w2 is preferably 30 μm or more, may be 45 μm or more, or may be 60 μm or more. The range of the width w2 may be determined by a combination of any one of the multiple upper limit candidate values and one of the multiple lower limit candidate values. The range of the width w2 may be determined by a combination of any two of the multiple upper limit candidate values, or a combination of any two of the multiple lower limit candidate values.
The depth h1 of the main groove 31 is preferably smaller than the depth h0 of the lower steam flow passage recess 12, depending on the width w2. The depth h1 is preferably 200 μm or less, and may be 150 μm or less, or may be 100 μm or less. On the other hand, the depth h1 is preferably 5 μm or more, and may be 10 μm or more, or may be 20 μm or more. The range of the depth h1 may be determined by a combination of any one of the multiple upper limit candidate values and one of the multiple lower limit candidate values. The range of the depth h1 may be determined by a combination of any two of the multiple upper limit candidate values, or a combination of any two of the multiple lower limit candidate values. The same applies to the depth of the communication groove described above.

Such a mainstream groove 31 is formed on the upper surface 13a of the lower flow passage wall 13 of the lower sheet 10. On the other hand, in this embodiment, no mainstream groove is formed on the lower surface 22a of the upper flow passage wall 22 of the upper sheet 20. In other words, the lower surface 22a is formed flat and is exposed to the mainstream groove 31. In this way, in the cross section of the mainstream groove 31, the entire mainstream groove 31 is covered by the flat lower surface 22a of the upper flow passage wall 22.

However, the present invention is not limited to this, and a main flow path 32 may also be provided in the upper sheet 20 as shown in Fig. 9. In this case, it can be considered similar to the main flow path 31 of the lower sheet 10 described above. Therefore, in the example shown in Fig. 9, the main flow path 31 and the main flow path 32 overlap each other to form a second flow path.
Alternatively, the main flow grooves 32 of the upper sheet 20 and the main flow grooves 31 of the lower sheet 10 may not overlap with each other and may form separate second flow paths.

The material used for the lower sheet 10 and the upper sheet 20 is not particularly limited as long as it has good thermal conductivity, but for example, it is preferable that the lower sheet 10 and the upper sheet 20 are formed of copper or a copper alloy. This can increase the thermal conductivity of the lower sheet 10 and the upper sheet 20. Therefore, the heat transport efficiency of the vapor chamber 1 can be increased. Alternatively, other metal materials such as aluminum or other metal alloy materials such as stainless steel can be used for the lower sheet 10 and the upper sheet 20 as long as the desired heat dissipation efficiency can be obtained.
However, the material does not necessarily have to be a metal material or a metal alloy material, and may be, for example, ceramics such as AlN, Si ₃ N ₄ , or Al ₂ O ₃ , or resins such as polyimide or epoxy.
Furthermore, the lower sheet 10 and the upper sheet 20 may be made of different materials, two or more types of materials may be laminated within one sheet, or different materials may be used depending on the location.

6, the thickness T0 of the vapor chamber 1 is preferably 1.0 mm or less, may be 0.75 mm or less, or may be 0.5 mm or less. On the other hand, the thickness T0 is preferably 0.1 mm or more, may be 0.15 mm or more, or may be 0.2 mm or more. The range of the thickness T0 may be determined by a combination of any one of the multiple upper limit candidate values and one of the multiple lower limit candidate values. The range of the thickness T0 may be determined by a combination of any two of the multiple upper limit candidate values, or a combination of any two of the multiple lower limit candidate values.
In this embodiment, the thickness T1 of the lower sheet 10 and the thickness T2 of the upper sheet 20 are shown to be equal, but this is not limited to this, and the thickness T1 of the lower sheet 10 and the thickness T2 of the upper sheet 20 do not have to be equal.

Next, the function of the vapor chamber 1 having such a configuration will be explained. First, the manufacturing method of the vapor chamber 1 will be explained using Figures 10 to 17, but the explanation of the half-etching process of the upper sheet 20 will be simplified. Note that Figures 10 to 17 show a cross section similar to the cross section of Figure 6.

First, as shown in FIG. 10, in the first preparation step, a flat lower material sheet M1 is prepared, which has an upper surface M1a (first sheet side) and a lower surface M1b (first opposite side) provided on the opposite side of the upper surface M1a.

After the first preparation process, as shown in FIG. 11, the lower material sheet M1 is half-etched in the lower flow path groove forming process to form the lower steam flow path recess 12 and the lower liquid flow path section 30 that form part of the sealed space 3.

In this case, first, a resist film (not shown) is formed on the upper surface M1a of the lower material sheet M1. For the resist film, an electrochemically deposited resist material that can be attached by an electric field can be preferably used, but other materials such as liquid resist materials may also be used as long as a resist film can be formed on the lower material sheet M1.

The resist film is then patterned using photolithography techniques to form resist openings (not shown).

Next, the upper surface M1a of the lower material sheet M1 is half-etched. As a result, the portion of the upper surface M1a corresponding to the resist opening of the resist film is half-etched, and the lower steam flow path recess 12 having the first lower flow path groove 12G1, the second lower flow path groove 12G2, and the third lower flow path groove 12G3, the lower flow path wall portion 13, and the lower peripheral wall 14 (see FIG. 3) are formed. At this time, the lower liquid flow path portion 30 having the main flow path 31 is formed on the upper surface 13a of the lower flow path wall portion 13. In addition, the lower material sheet M1 is etched from the upper surface M1a and the lower surface M1b so as to have an outer contour shape as shown in FIG. 4, and a predetermined outer contour shape is obtained. Note that half etching means etching for forming a recess that does not penetrate the material. For this reason, the depth of the recess formed by half etching is not limited to being half the thickness of the lower sheet 10. The etching solution may be, for example, an iron chloride-based etching solution such as an aqueous solution of ferric chloride, or a copper chloride-based etching solution such as an aqueous solution of copper chloride.

The resist film is then removed. In this way, by forming the lower vapor flow path recess 12 and the lower liquid flow path section 30, etc., in a single half-etching process, the number of half-etching processes can be reduced, and the manufacturing cost of the vapor chamber 1 can be reduced. However, this is not limited to this, and the lower vapor flow path recess 12 may be formed as a first half-etching process, and the lower liquid flow path section 30 may be formed as a second half-etching process thereafter. In this case, the depth h0 of the lower vapor flow path recess 12 and the depth h1 of the lower liquid flow path section 30 (i.e., the main groove 31 and the connecting groove) can be easily made different.

In this manner, the lower sheet 10 of this embodiment is produced.

Meanwhile, the upper sheet 20 is produced in the same manner as the lower sheet 10.

First, as shown in FIG. 12, in the second preparation step, a flat upper material sheet M2 is prepared, which has a lower surface M2a (second sheet side surface) and an upper surface M2b (second opposite side surface) provided on the opposite side of the lower surface M2a.

After the second preparation step, as shown in FIG. 13, the upper material sheet M2 is half-etched as an upper flow passage groove forming step to form an upper steam flow passage recess 21 that constitutes a part of the sealed space 3. In this case, the lower surface M2a of the upper material sheet M2 is half-etched in the same manner as in the lower flow passage groove forming step to form an upper steam flow passage recess 21 having a first upper flow passage groove 21G1, a second upper flow passage groove 21G2, and a third upper flow passage groove 21G3, an upper flow passage wall portion 22, and an upper peripheral wall 23 (see FIG. 3) on the lower surface M2a. In addition, the upper material sheet M2 is etched from the lower surface M2a and the upper surface M2b so as to have an outer contour shape as shown in FIG. 5, and a predetermined outer contour shape is obtained.

In this manner, the upper sheet 20 of this embodiment is produced.

After the lower flow channel forming process and the upper flow channel forming process, as shown in FIG. 14, the lower sheet 10 having the lower steam flow channel recess 12 and the upper sheet 20 having the upper steam flow channel recess 21 are temporarily fixed as a temporary fixing process. In this case, the lower sheet 10 and the upper sheet 20 are first positioned using the lower alignment hole 15 (see FIG. 2 and FIG. 4) of the lower sheet 10 and the upper alignment hole 24 (see FIG. 2 and FIG. 5) of the upper sheet 20. Then, the lower sheet 10 and the upper sheet 20 are fixed. The fixing method is not particularly limited, but for example, the lower sheet 10 and the upper sheet 20 may be fixed by resistance welding to the lower sheet 10 and the upper sheet 20. In this case, as shown in FIG. 14, it is preferable to perform resistance welding on the lower peripheral wall 14 and the upper peripheral wall 23 in a spot manner using an electrode rod 40. Laser welding may be performed instead of resistance welding. Alternatively, ultrasonic waves may be applied to ultrasonically bond and fix the lower sheet 10 and the upper sheet 20 together. Furthermore, an adhesive may be used, but it is preferable to use an adhesive that does not contain organic components or that contains only a small amount of organic components. In this way, the lower sheet 10 and the upper sheet 20 are fixed in a positioned state.

After the temporary fixing process, as shown in FIG. 15, the lower sheet 10 and the upper sheet 20 are permanently bonded by diffusion bonding in the bonding process. Diffusion bonding is a method in which the lower sheet 10 and the upper sheet 20 to be bonded are brought into close contact with each other, and in a controlled atmosphere such as a vacuum or an inert gas, the sheets 10 and 20 are pressurized in the direction of bonding and heated to bond them together, utilizing the diffusion of atoms that occurs at the bonding surface. In diffusion bonding, the materials of the lower sheet 10 and the upper sheet 20 are heated to a temperature close to the melting point, but since it is lower than the melting point, it is possible to avoid melting of the sheets 10 and 20. More specifically, the upper surface 14a of the lower peripheral wall 14 of the lower sheet 10 and the lower surface 23a of the upper peripheral wall 23 of the upper sheet 20 are diffusion bonded as bonding surfaces. As a result, a sealed space 3 is formed between the lower sheet 10 and the upper sheet 20 by the lower peripheral wall 14 and the upper peripheral wall 23. In addition, the upper surface 13a of the lower flow path wall 13 of the lower sheet 10 and the lower surface 22a of the upper flow path wall 22 of the upper sheet 20 are diffusion bonded to each other as a bonding surface, improving the mechanical strength of the vapor chamber 1. The lower liquid flow path portion 30 formed on the upper surface 13a of the lower flow path wall 13 remains as a second flow path, which is a flow path for the working fluid 2.

In the joining process, heat is applied to the lower sheet 10 and the upper sheet 20 until they reach a predetermined temperature, and a predetermined pressure is applied. For example, if the lower sheet 10 and the upper sheet 20 are made of copper, the thickness T1 of the lower sheet 10 is 0.2 mm, the thickness T2 of the upper sheet 20 is 0.2 mm, and the width w1 of each of the lower flow grooves 12G1, 12G2, 12G3 and each of the upper flow grooves 21G1, 21G2, 21G3 is 1000 μm and the depth h0 is 150 μm, the lower sheet 10 and the upper sheet 20 may be heated to 810° C. and a pressure of 2 MPa may be applied.

As a result, the lower steam flow path bottom 10c thermally expands as shown in Fig. 16. A flat spacer (not shown) is abutted against the lower surface 10b of the lower sheet 10 to apply pressure evenly to the lower sheet 10, so the lower steam flow path bottom 10c bends toward the upper surface 10a. As a result, a lower sheet recess 50 is formed on the lower surface 10b of the lower sheet 10, and a lower bottom surface protrusion 51 is formed on the bottom surface 12a of the lower steam flow path recess 12. In addition, as the thermally expanded portion bends, the thickness t3 (see Fig. 16) of the lower steam flow path bottom 10c after thermal expansion becomes smaller than the thickness t3' (see Fig. 15) of the lower steam flow path bottom 10c before thermal expansion. The lower sheet recess 50 and the lower bottom surface protrusion 51 are formed at positions that overlap the first lower flow channel 12G1, the second lower flow channel 12G2, and the third lower flow channel 12G3 in a plan view.

Similarly, the upper steam flow path bottom 20c thermally expands. Since a flat spacer (not shown) is abutted against the upper surface 20b of the upper sheet 20 to uniformly press the upper sheet 20, the upper steam flow path bottom 20c bends toward the lower surface 20a. As a result, an upper sheet recess 60 is formed on the upper surface 20b of the upper sheet 20, and an upper bottom surface protrusion 61 is formed on the bottom surface 21a of the upper steam flow path recess 21. In addition, due to the bending of the thermally expanded portion, the thickness t5 (see FIG. 16) of the upper steam flow path bottom 20c after thermal expansion becomes smaller than the thickness t5' (see FIG. 15) of the upper steam flow path bottom 20c before thermal expansion. The upper sheet recess 60 and the upper bottom surface protrusion 61 are formed at positions overlapping the first upper flow path groove 21G1, the second upper flow path groove 21G2, and the third upper flow path groove 21G3 in a plan view.

After the joining process, as shown in FIG. 17, in the injection process, the working fluid 2 is injected into the sealed space 3 from the injection section 4 (see FIG. 2). At this time, the sealed space 3 is first evacuated to reduce the pressure, and then the working fluid 2 is injected into the sealed space 3. During injection, the working fluid 2 passes through the injection flow path formed by the lower injection flow path recess 17 and the upper injection flow path recess 26.

After the working fluid 2 is injected, the above-mentioned injection flow path is sealed. For example, the injection part 4 may be irradiated with a laser to partially melt the injection part 4 and seal the injection flow path. This blocks communication between the sealed space 3 and the outside, and the working fluid 2 is sealed in the sealed space 3. In this way, the working fluid 2 in the sealed space 3 is prevented from leaking to the outside. For sealing, the injection part 4 may be crimped or brazed.

In this manner, the vapor chamber 1 of this embodiment is obtained.

Next, we will explain how the vapor chamber 1 operates, i.e., how the device D is cooled.

The vapor chamber 1 obtained as described above is installed in the 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 sheet 10. At this time, the vapor chamber may be attached to the device D via a thermal interface material, such as grease or a tape containing a thermally conductive filler, placed on the lower surface 10b of the vapor chamber 1, or an adhesive sheet.
Since the amount of working fluid injected into the sealed space 3 is small, the working fluid 2 in the sealed space 3 adheres to the wall surfaces of the sealed space 3, i.e., the wall surface (including the bottom surface 12a) of the lower steam flow path recess 12 and the wall surface (including the bottom surface 21a) of the upper steam flow path recess 21, due to its surface tension.

In this state, when the device D generates heat, the working fluid 2 present in the evaporation section 11 of the lower steam flow passage recess 12 receives heat from the device D. At this time, part of the heat from the device D is transferred to the working fluid 2 through the lower sheet recess 50 of the lower sheet 10 and the lower bottom surface protrusion 51 of the lower steam flow passage recess 12. The received heat is absorbed as latent heat, and the working fluid 2 evaporates (vaporizes), generating steam. Most of the generated steam diffuses away from the device D through the first flow passage (the flow passage formed by the first lower flow passage groove 12G1 and the first upper flow passage groove 21G1, and the flow passage formed by the second lower flow passage groove 12G2 and the second upper flow passage groove 21G2) constituting the sealed space 3 (see the solid line arrows in FIG. 4 and the solid line arrows in FIG. 5). As a result, the steam leaves the evaporation section 11, and most of the steam is transported toward the peripheral portion, which has a relatively low temperature. The steam diffused to the peripheral portion is cooled by dissipating heat at the peripheral portion. The heat received by the lower sheet 10 and the upper sheet 20 from the steam at the periphery is transferred to the outside via the housing member H (see FIG. 3). At this time, part of the heat from the steam is transferred to the outside via the upper bottom surface protrusion 61 of the upper steam flow path recess 21 and the upper sheet recess 60 of the upper sheet 20, and is also transferred to the outside via the lower sheet recess 50 of the lower sheet 10 and the lower bottom surface protrusion 51 of the lower steam flow path recess 12.

By dissipating heat to the periphery, the steam loses the latent heat absorbed in the evaporation section 11 and condenses to become the working fluid 2. Most of the working fluid 2 adheres to the wall surface of the lower steam flow recess 12 or the wall surface of the upper steam flow recess 21, and reaches the lower liquid flow section 30. Here, since the working fluid 2 continues to evaporate in the evaporation section 11, the working fluid 2 in the part of the lower liquid flow section 30 other than the evaporation section 11 is transported by capillary action toward the evaporation section 11 (see the dashed arrow in FIG. 4). As a result, the working fluid 2 adhering to the wall surface of the lower steam flow recess 12 and the wall surface of the upper steam flow recess 21 moves toward the lower liquid flow section 30 and enters the lower liquid flow section 30. That is, it passes through a connecting groove (not shown) and enters the second flow path consisting of the mainstream groove 31, and the working fluid 2 is filled in each mainstream groove 31 and each connecting groove. As a result, the filled working fluid 2 obtains a driving force toward the evaporation section 11 due to the capillary action of each main groove 31, and is smoothly transported toward the evaporation section 11 through the second flow path.

The working liquid 2 that reaches the evaporation section 11 receives heat from the device D again and evaporates. In this way, the working liquid 2 circulates through the vapor chamber 1 while repeatedly changing phases, i.e., evaporating and condensing, and transfers and releases the heat of the device D. As a result, the device D is cooled.

According to the vapor chamber 1 of this embodiment, a lower sheet recess 50 recessed toward the lower steam flow path recess 12 is provided at a position on the lower surface 10b of the lower sheet 10 that overlaps with the lower steam flow path recess 12 in a plan view. This increases the surface area of the lower surface 10b that acts as a heat-receiving surface that receives heat from the device D. This reduces the thermal resistance between the device D and the lower surface 10b, allowing heat to be efficiently transferred from the device D to the working fluid 2. As a result, the heat transport efficiency can be improved. Furthermore, the lower sheet recess 50 increases the adhesion area of the thermal interface material and the adhesive sheet, thereby improving adhesion to the device D.
The positions of the device D and the housing H relative to the vapor chamber 1 are not limited to this embodiment, and the positions of the device D and the housing H may be interchanged, or the housing H may be provided between the device D and the vapor chamber 1.

In addition, according to the vapor chamber 1 of this embodiment, a lower bottom surface convex portion 51 that protrudes inward of the lower steam flow path concave portion 12 is provided at a position of the bottom surface 12a of the lower steam flow path concave portion 12 that overlaps with the lower sheet concave portion 50 in a plan view. This allows the surface area of the bottom surface 12a of the lower steam flow path concave portion 12 to be increased. Therefore, the thermal resistance between the lower sheet 10 and the working fluid 2 can be reduced, and heat can be transferred more efficiently from the device D to the working fluid 2. That is, when the device D is started, the working fluid 2 that has adhered to the wall surface of the lower steam flow path concave portion 12 can be quickly evaporated. Therefore, the diffusion of the steam generated in the lower liquid flow path portion 30 can be prevented from being hindered by the working fluid 2 that has adhered to the wall surface of the lower steam flow path concave portion 12, and the steam can be diffused smoothly. As a result, the heat transport efficiency can be further improved. Furthermore, because the lower sheet recess 50 and the lower bottom surface protrusion 51 are formed by thermal expansion during diffusion bonding, the thickness t3 (see FIG. 16) of the lower steam flow path bottom 10c can be reduced. This also reduces the thermal resistance between the device D and the working fluid 2.

In addition, according to this embodiment, an upper sheet recess 60 that is recessed toward the upper steam flow path recess 21 is provided at a position on the upper surface 20b of the upper sheet 20 that overlaps with the upper steam flow path recess 21 in a plan view. This increases the surface area of the upper surface 20b that acts as a heat dissipation surface that releases heat to the outside. This reduces the thermal resistance between the upper surface 20b and the outside, allowing heat to be efficiently transferred from the vapor of the working fluid 2 to the outside. As a result, the heat transport efficiency can be improved.

In addition, according to this embodiment, the upper bottom surface convex portion 61 protruding inward of the upper steam flow path concave portion 21 is provided at a position of the bottom surface 21a of the upper steam flow path concave portion 21 that overlaps with the upper sheet concave portion 60 in a plan view. This increases the surface area of the bottom surface 21a of the upper steam flow path concave portion 21. Therefore, the thermal resistance between the upper sheet 20 and the working fluid 2 can be reduced, and heat can be transferred more efficiently from the device D by the working fluid 2. That is, when the device D is started, the liquid working fluid 2 that has adhered to the wall surface of the upper steam flow path concave portion 21 can be quickly evaporated. Therefore, the diffusion of the vapor of the working fluid 2 evaporated in the lower liquid flow path portion 30 can be prevented from being hindered by the working fluid 2 that has adhered to the wall surface of the upper steam flow path concave portion 21, and the vapor can be diffused smoothly. As a result, the heat transport efficiency can be further improved. Furthermore, since the upper sheet concave portion 60 and the upper bottom surface convex portion 61 are formed by thermal expansion during diffusion bonding, the thickness t5 (see FIG. 16) can be reduced. In this respect, the thermal resistance between the working fluid 2 and the outside can also be reduced.

In addition, according to this embodiment, as described above, a lower sheet recess 50 is provided on the lower surface 10b of the lower sheet 10. As a result, the surface area of the lower surface 10b is increased even in the peripheral portion (part away from the device D) of the lower steam flow path recess 12 that releases heat to the outside, so that the thermal resistance between the lower surface 10b and the outside can be reduced. This allows heat to move efficiently from the steam to the outside, improving the heat transport efficiency.

In addition, according to this embodiment, as described above, a lower bottom surface protrusion 51 is provided on the bottom surface 12a of the lower steam flow path recess 12. As a result, the surface area of the bottom surface 12a of the lower steam flow path recess 12 is increased even in the peripheral portion of the lower steam flow path recess 12 that releases heat to the outside, so that the thermal resistance between the lower sheet 10 and the working fluid 2 can be reduced. This allows heat to be transferred more efficiently from the steam to the outside, and further improves the heat transport efficiency.

In addition, according to this embodiment, the lower sheet recess 50 is disposed between a pair of adjacent lower flow path walls 13. This allows the lower sheet recess 50 to be easily formed by adjusting the temperature of the lower sheet 10 and the upper sheet 20 heated during diffusion bonding and/or the pressure applied to each sheet 10, 20. This prevents the manufacturing process of the vapor chamber 1 from becoming complicated, and prevents increases in manufacturing costs.

In addition, according to this embodiment, the upper sheet recess 60 is disposed between a pair of adjacent upper flow path walls 22. This allows the upper sheet recess 60 to be easily formed by adjusting the temperature of the lower sheet 10 and the upper sheet 20 heated during diffusion bonding and/or the pressure applied to each sheet 10, 20. This prevents the manufacturing process of the vapor chamber 1 from becoming complicated, and prevents increases in manufacturing costs.

In addition, according to this embodiment, the lower sheet recess 50 and the upper sheet recess 60 can be formed during the joining process. This prevents the manufacturing process of the vapor chamber 1 from becoming complicated, and prevents an increase in manufacturing costs.

In addition, in this embodiment, the vapor chamber 1 is thinned at this portion by the lower sheet recess 50 on the lower surface 10b of the lower sheet 10 and the upper sheet recess 60 on the upper surface 20b of the upper sheet 20. Therefore, even in a situation where the internal pressure of the vapor chamber 1 increases due to operation and causes swelling, and in a situation where the working fluid expands due to freezing of the working fluid when the vapor chamber 1 is not in operation and causes swelling, the vapor chamber 1 does not swell until the lower sheet recess 50 and the upper sheet recess 60 become flush with other portions of the lower surface 10b and the upper surface 20b and swell further. Therefore, the occurrence of problems due to swelling of the vapor chamber 1 can be mitigated. And, in the case where the lower sheet recess 50 and the lower bottom surface protrusion 51 are provided at a position where they overlap in a plan view as in this embodiment, the lower sheet recess 50 has a curved shape, so that a higher effect can be obtained.

In addition, when the thickness t3 of the lower steam flow path bottom 10c provided between the lower surface 10b of the lower sheet 10 and the lower steam flow path recess 12 is made smaller than the thickness t4 of the lower liquid flow path bottom 10d provided between the lower surface 10b and the lower liquid flow path section 30 (see FIG. 6), the lower steam flow path recess 12 can be brought closer to the lower surface 10b that receives the heat of the device D than the lower liquid flow path section 30. This allows the heat from the device D to reach the lower steam flow path recess 12 earlier than the lower liquid flow path section 30, and it is possible to promote the evaporation of the working fluid 2 in the lower steam flow path recess 12. That is, when the device D is started, the working fluid 2 attached to the wall surface of the steam flow path recess 12 can be quickly evaporated. Therefore, it is possible to suppress the diffusion of the steam generated in the lower liquid flow path section 30 from being hindered by the working fluid 2 attached to the wall surface of the lower steam flow path recess 12, and the steam can be diffused smoothly. On the other hand, the lower liquid flow path section 30 can be located farther from the lower surface 10b than the lower vapor flow path recess 12, which can prevent the working liquid from evaporating. This can prevent air bubbles from being generated by vapor of the working liquid 2 in the lower liquid flow path section 30, which can prevent flow path blockages that would impede the flow of the working liquid 2.

In the vapor chamber 1 of the present embodiment described above, an example has been described in which the lower sheet recess 50 is provided on the lower surface 10b of the lower sheet 10, and the upper sheet recess 60 is provided on the upper surface 20b of the upper sheet 20. However, this is not limited to the above, and one of the lower sheet recess 50 and the upper sheet recess 60 does not have to be provided. Even in this case, the heat transport efficiency can be improved. When the lower sheet recess 50 is not provided, the upper sheet 20 becomes the first sheet, and the upper sheet recess 60 becomes the first sheet recess.

In addition, in the vapor chamber 1 of the present embodiment described above, an example has been described in which the lower bottom surface protrusion 51 provided on the bottom surface 12a of the lower steam flow path recess 12 extends continuously in an elongated manner. However, this is not limited to this. For example, the lower bottom surface protrusion 51 may be formed intermittently in the corresponding direction of the first direction X and the second direction Y. In this case, the surface area of the bottom surface 12a of the lower steam flow path recess 12 can be increased, and the thermal resistance between the lower sheet 10 and the working fluid 2 can be further reduced. In other words, when the device D is started up, the working fluid 2 attached to the wall surface of the lower steam flow path recess 12 can be quickly evaporated.

In addition, in the vapor chamber 1 of the present embodiment described above, an example has been described in which the upper bottom surface protrusion 61 provided on the bottom surface 21a of the upper steam flow path recess 21 extends continuously in an elongated manner. However, this is not limited to this, and the upper bottom surface protrusion 61 may be formed intermittently in the corresponding direction of the first direction X and the second direction Y. In this case, the surface area of the bottom surface 21a of the upper steam flow path recess 21 can be increased, and the thermal resistance between the upper sheet 20 and the working fluid 2 can be further reduced. In other words, when the device D is started up, the working fluid 2 attached to the wall surface of the upper steam flow path recess 21 can be quickly evaporated.

In the vapor chamber 1 of the present embodiment described above, an example has been described in which the upper flow passage wall 22 of the upper sheet 20 extends in an elongated manner along the longitudinal direction of the vapor chamber 1. However, this is not limited to this, and the shape of the upper flow passage wall 22 is arbitrary. For example, the upper flow passage wall 22 may be formed as a cylindrical boss. Even in this case, the upper sheet recess 60 can be formed between a pair of adjacent upper flow passage walls 22. In this case, it is preferable that the upper flow passage wall 22 is arranged so as to overlap the lower flow passage wall 13 in a plan view, and the lower surface 22a of the upper flow passage wall 22 is brought into contact with the upper surface 13a of the lower flow passage wall 13.

Furthermore, in the vapor chamber 1 of the present embodiment described above, an example has been described in which the lower sheet recess 50, the lower bottom surface protrusion 51, the upper sheet recess 60, and the upper bottom surface protrusion 61 are formed during the joining process. However, this is not limited to this. For example, the lower sheet recess 50 and the lower bottom surface protrusion 51 may be formed during the lower flow path groove forming process shown in FIG. 11. In this case, as shown in FIG. 18, the lower sheet recess 50 and the lower bottom surface protrusion 51 may be formed by pressing together with the lower steam flow path recess 12 and the lower liquid flow path section 30.

More specifically, after preparing the lower material sheet M1 in the first preparation step shown in FIG. 10, the lower material sheet M1 is pressed in the lower flow channel forming step. In this case, the upper surface 10a of the lower sheet 10 is pressed via a first lower die 70, and the lower surface 10b is pressed via a second lower die 71.

The first lower die 70 includes a die protrusion 70a having a shape corresponding to each of the lower flow grooves 12G1, 12G2, and 12G3 of the lower steam flow recess 12, and a die protrusion 70b having a shape corresponding to the lower liquid flow path section 30. By pressing the flat lower material sheet M1 using the first lower die 70, as shown in FIG. 18, the lower steam flow path recess 12 including the lower bottom surface protrusion 51 and the lower liquid flow path section 30 can be formed. In addition, the second lower die 71 includes a die protrusion 71a having a shape corresponding to the lower sheet recess 50. This allows the lower sheet recess 50 to be formed on the lower surface M1b of the lower material sheet M1.

Similarly, the upper sheet recess 60 and the upper bottom surface protrusion 61 may also be formed during the upper flow passage groove forming process that forms the upper steam flow passage recess 21. In this case, as shown in FIG. 19, the upper sheet recess 60 and the upper bottom surface protrusion 61 may be formed by pressing together with the upper steam flow passage recess 21.

More specifically, after preparing the upper material sheet M2 in the second preparation step shown in FIG. 12, the upper material sheet M2 is pressed in the upper flow channel forming step. In this case, the lower surface 20a of the upper sheet 20 is pressed via the first upper die 80, and the upper surface 20b is pressed via the second upper die 81.

The first upper die 80 includes a die protrusion 80a having a shape corresponding to each of the upper flow channel grooves 21G1, 21G2, and 21G3 of the upper steam flow channel recess 21. By pressing the flat upper material sheet M2 using the first upper die 80, the upper steam flow channel recess 21 including the upper bottom surface protrusion 61 can be formed as shown in FIG. 19. In addition, the second upper die 81 includes a die protrusion 81a having a shape corresponding to the upper sheet recess 60. This allows the upper sheet recess 60 to be formed on the upper surface M2b of the upper material sheet M2.

When the lower sheet recess 50 is formed by pressing as the lower flow channel forming process and the upper sheet recess 60 is formed by pressing as the upper flow channel forming process, the temperature of the lower sheet 10 and the upper sheet 20 and the pressure applied to each sheet 10, 20 can be any as long as the sheets 10, 20 can be permanently joined, facilitating diffusion bonding.

In addition, since the lower sheet recess 50 and the lower bottom surface protrusion 51 are formed by the press process, the thickness t3 (see FIG. 16) after the press process can be made smaller than the thickness t3' (see FIG. 15) before the press process. This allows the thermal resistance between the device D and the working fluid 2 to be reduced. Similarly, since the upper sheet recess 60 and the upper bottom surface protrusion 61 are formed, the thickness t5 (see FIG. 16) after the press process can be made smaller than the thickness t5' (see FIG. 15) before the press process. This allows the thermal resistance between the device D and the working fluid 2 to be reduced.

The above describes the manufacture of a vapor chamber by etching and the manufacture of a vapor chamber by press processing, but the manufacturing method is not limited to these, and the vapor chamber can also be manufactured by cutting processing, laser processing, and processing with a 3D printer.
For example, when manufacturing a vapor chamber using a 3D printer, it is not necessary to create the vapor chamber by joining multiple sheets, and it is possible to create a vapor chamber with no joints.

In the vapor chamber 1 of this embodiment described above, an example has been described in which the upper steam flow passage recess 21 is provided on the lower surface 20a of the upper sheet 20. However, the upper steam flow passage recess 21 does not have to be provided. In this case, the lower surface 20a of the upper sheet 20 is formed flat overall, covering and exposing the first lower flow passage groove 12G1, the second lower flow passage groove 12G2, and the third lower flow passage groove 12G3 of the lower steam flow passage recess 12. This improves the mechanical strength of the vapor chamber 1.

Furthermore, in the vapor chamber 1 of this embodiment described above, an example has been described in which the lower steam flow path recess 12 is provided on the upper surface 10a of the lower sheet 10. However, this is not limited thereto, and as shown in Figures 20 to 22, the lower steam flow path recess 12 does not have to be provided.

20, the upper surface 10a of the lower sheet 10 other than the area where the main flow grooves 31 and the communication grooves of the lower liquid flow path section 30 are formed is formed flat, and covers and exposes the first upper flow path groove 21G1, the second upper flow path groove 21G2, and the third upper flow path groove 21G3 of the upper steam flow path recess 21. This makes it possible to improve the mechanical strength of the vapor chamber 1.
In the modified example shown in FIG. 20, the portions of the upper surface 10a and the lower surface 10b of the lower sheet 10 that overlap the upper steam flow path recess 21 in a plan view are formed flat.

In the modified example shown in FIG. 21, a lower sheet recess 50 is formed in a portion of the lower surface 10b of the lower sheet 10 that overlaps with the upper steam flow path recess 21. In addition, an upper surface protrusion 90 that protrudes into the upper steam flow path recess 21 is provided in a position of the upper surface 10a of the lower sheet 10 that overlaps with the lower sheet recess 50 in a plan view. This upper surface protrusion 90 can have a shape similar to the lower bottom surface protrusion 51 shown in FIG. 6 and can be formed in a similar manner. In these modified examples, an example is shown in which the thickness T2 of the upper sheet 20 is larger than the thickness T1 of the lower sheet 10. However, this is not limited to this, and as long as a gap through which steam can flow is formed between the upper bottom surface protrusion 61 and the upper surface 10a, the thickness T2 of the upper sheet 20 does not have to be larger than the thickness T1 of the lower sheet 10.

In the modified example shown in Figures 20 and 21, a lower liquid flow path section 30 is provided on the lower sheet 10 as the second flow path through which the working fluid 2 passes, and a first upper flow path groove 21G1 is provided on the upper sheet 20 as the first flow path through which steam passes. This allows the second flow path, which is the liquid flow path section, and the first flow path, which is the steam flow path section, to be formed on different sheets. This makes it easy to make the depth of the liquid flow path section and the depth of the steam flow path section different.

22, both the upper surface 10a and the lower surface 10b of the lower sheet 10 are flat. Meanwhile, the main flow passage wall portion 22 on the lower surface 20a side of the upper sheet 20 has a main flow passage groove 32 and a communication groove which serve as the second flow passage.
A part of the upper surface 10a of the lower sheet 10 covers the first upper flow passage groove 21G1, the second upper flow passage groove 21G2, and the third upper flow passage groove 21G3, which are the first flow passages, and is exposed. This makes it possible to improve the mechanical strength of the vapor chamber 1.

In addition, in the modified example shown in Figures 20 to 22, the precision of the positioning of the lower sheet 10 and the upper sheet 20 can be relaxed. That is, when the lower sheet 10 is provided with a lower steam flow path recess 12, it is preferable to position the lower sheet 10 and the upper sheet 20 with high precision so that the wall surface of the lower steam flow path recess 12 and the wall surface of the upper steam flow path recess 21 are aligned. In contrast, in the modified example shown in Figures 20 to 22, the lower sheet 10 is not provided with a lower steam flow path recess 12, so that the precision of the positioning of the lower sheet 10 and the upper sheet 20 can be relaxed.

So far, an example of the vapor chamber 1 has been described that is made up of two sheets, the first sheet being the lower sheet 10 and the second sheet being the upper sheet 20. However, this is not limited to this, and the vapor chamber may be made up of three or more sheets as shown in Figures 23 to 25. Figures 23 and 24 are examples of a vapor chamber made up of three sheets, and Figure 25 is an example of a vapor chamber made up of four sheets.

The vapor chamber shown in FIG. 23 is composed of a laminate of a lower sheet 10 (first sheet), an upper sheet 20 (second sheet), and an intermediate sheet 100 (third sheet).
The intermediate sheet 100 is disposed so as to be sandwiched between the lower sheet 10 and the upper sheet 20, with the upper surface 10a of the lower sheet 10 contacting the lower surface 100b of the intermediate sheet 100 and the lower surface 20a of the upper sheet 20 contacting the upper surface 100a of the intermediate sheet 100 and being joined to each other in the manner described above.

Here, the lower sheet 10 has a lower sheet recess 50 and a lower bottom surface protrusion 51, and the other portions of both the upper surface 10a and the lower surface 10b are flat.
Similarly, the upper sheet 20 has an upper sheet recess 60 and an upper bottom surface protrusion 61, and the other portions of both the upper surface 20a and the lower surface 10b are flat.

The intermediate sheet 100 is provided with a flow channel 101 , a flow channel wall 102 , and a main flow channel 32 .
The flow channel 101 is a channel that penetrates the intermediate sheet 100 in the thickness direction, and is a channel that constitutes the first flow channel by overlapping the first lower flow channel 12G1 and the first upper flow channel 21G1 described above, and is arranged in a shape and position corresponding thereto. The intermediate sheet 100 is provided with a groove that constitutes the first flow channel by overlapping the second lower flow channel 12G2 and the second upper flow channel 21G2 described above, and a groove that corresponds to the flow channel formed by overlapping the third lower flow channel 12G3 and the third upper flow channel 21G3.
The flow path wall 102 is a wall portion that is disposed in a shape and position corresponding to a wall portion obtained by overlapping the lower flow path wall portion 13 and the lower flow path wall portion 22 .
The main flow passage 32 is a groove having a shape and arrangement that configures a second flow passage similar to the main flow passage 32 described above, and is provided on the lower surface 100 b of the intermediate sheet 100 .

The lower sheet recess 50, the lower bottom surface protrusion 51, the upper sheet recess 60, and the upper bottom surface protrusion 61 are positioned so as to overlap the flow channel 101 when viewed from above the vapor chamber.

The vapor chamber shown in FIG. 24 is also a laminate of a lower sheet 10 (first sheet), an upper sheet 20 (second sheet), and an intermediate sheet 100 (third sheet).
In the vapor chamber shown in Fig. 24, the cross-sectional area of the main flow groove 32 is made larger than that of the vapor chamber shown in Fig. 23, and a wick material 103 is disposed therein. The wick material 103 is a material having a fine structure that generates a capillary force, and examples of the wick material include sintered particles, stranded wire, nonwoven fabric, and mesh material. Note that the main flow groove 32 in this embodiment is formed larger than the main flow groove 32 in the above embodiment, but the relationship between the first flow path and the second flow path can be considered as described above.
According to this, since the capillary force can be generated by the wick material 103, it is not necessary to fabricate the main groove 32 finely, and therefore the management of the shape precision can be relaxed.

The vapor chamber shown in FIG. 25 is composed of a laminate of a lower sheet 10 (first sheet), an upper sheet 20 (second sheet), and two intermediate sheets 100 (third sheet) and 110 (fourth sheet).
The intermediate sheets 100, 110 are disposed so as to be sandwiched between the lower sheet 10 and the upper sheet 20, with the upper surface 10a of the lower sheet 10 contacting the lower surface 100b of the intermediate sheet 100, the upper surface 100a of the intermediate sheet 100 contacting the lower surface 110b of the intermediate sheet 110, and the lower surface 20a of the upper sheet 20 contacting the upper surface 110a of the intermediate sheet 110, and being bonded to each other. The manner of bonding is as described above.

Here, the lower sheet 10 has a lower sheet recess 50 and a lower bottom surface protrusion 51, and the other portions of both the upper surface 10a and the lower surface 10b are flat.
Similarly, the upper sheet 20 has an upper sheet recess 60 and an upper bottom surface protrusion 61, and the other portions of both the upper surface 20a and the lower surface 10b are flat.

The intermediate sheet 100 is provided with a first lower flow passage groove 12G1, a lower flow passage wall portion 13, and a main flow passage groove 31.
The first lower flow groove 12G1 in this embodiment is a groove that penetrates the intermediate sheet 100 in the thickness direction, but can otherwise be disposed in the same shape and position as the first lower flow groove 12G1 described above. Similarly, the intermediate sheet 100 also has flow grooves corresponding to the second lower flow groove 12G2 and the third lower flow groove 12G3 described above.
The lower flow path wall portion 13 can be arranged in the same shape and position as the lower flow path wall portion 13 described above.
The main flow groove 31 in this embodiment is a groove that penetrates the intermediate sheet 100 in the thickness direction, and has the same shape and arrangement as the main flow groove 32 described above, and is provided in the lower flow passage wall portion 13 of the intermediate sheet 100.

The intermediate sheet 110 is provided with a first upper flow passage groove 21G1 and an upper flow passage wall portion 22.
The second upper flow groove 21G1 in this embodiment is a groove that penetrates the intermediate sheet 110 in the thickness direction, but can otherwise be disposed in the same shape and position as the above-mentioned second upper flow groove 21G1. Similarly, the intermediate sheet 110 also has flow grooves corresponding to the above-mentioned second upper flow groove 21G2 and third upper flow grooves corresponding to 21G3.
The upper flow path wall portion 22 may be arranged in the same shape and position as the upper flow path wall portion 22 described above.

The first lower flow passage groove 12G1 and the first upper flow passage groove 21G1 are arranged to overlap each other in a plan view of the vapor chamber to form a first flow passage. On the other hand, the lower flow passage wall portion 13 and the upper flow passage wall portion 22 are arranged to overlap each other in a plan view of the vapor chamber to form a second flow passage by the main flow passage groove 31.
Furthermore, the lower sheet recess 50, the lower bottom surface protrusion 51, the upper sheet recess 60, and the upper bottom surface protrusion 61 are positioned so as to overlap the first lower flow groove 12G1 and the first upper flow groove 21G1 when viewed in a plan view of the vapor chamber.

Figure 26 shows a cross-sectional view illustrating a vapor chamber in which, instead of the lower sheet concave portion 50, lower bottom surface convex portion 51, upper sheet concave portion 60, and upper bottom surface convex portion 61 provided in the vapor chamber described up to this point, the concave-convex relationship is reversed, with a lower sheet convex portion 50', a lower bottom surface concave portion 51', an upper sheet convex portion 60', and an upper bottom surface concave portion 61'.
In this vapor chamber, a lower sheet convex portion 50' is arranged on the lower surface 10b of the lower sheet 10, and an upper sheet convex portion 60' is arranged on the upper surface 20b of the upper sheet 20, at positions overlapping with the first lower flow passage groove 12G1 and the first upper flow passage groove 21G1 in a plan view of the vapor chamber. Meanwhile, a lower bottom surface concave portion 51' is arranged on the upper surface 10a side of the lower sheet 10, and an upper bottom surface concave portion 61' is arranged on the lower surface 20a of the upper sheet 20.
These lower sheet convex portion 50', lower bottom surface concave portion 51', upper sheet convex portion 60', and upper bottom surface concave portion 61' can be considered to be similar to the lower sheet concave portion 50, lower bottom surface convex portion 51, upper sheet concave portion 60, and upper bottom surface convex portion 61 provided in the above-mentioned form, except that their concave-convex relationships are opposite.

In addition to the above-mentioned effects, a vapor chamber of this type can reduce the flow resistance of the first flow path (vapor flow path) and reduce the possibility of the vapor flow path becoming clogged with condensate.

The above-mentioned embodiments and modifications of the present disclosure are not limited to the above-mentioned embodiments and modifications, and may be embodied without departing from the spirit of the present disclosure. In addition, various embodiments can be realized by appropriately combining the multiple components disclosed in the above-mentioned embodiments and modifications. Some components may be deleted from all the components shown in each embodiment and modification.

1 Vapor chamber 2 Working fluid 3 Sealed space 4 Injection section 10 Lower sheet 11 Evaporation section 12 Lower steam flow path recess 12a Bottom surface 13 Lower flow path wall 13a Upper surface 20 Upper sheet 21 Upper steam flow path recess 21a Bottom surface 22 Upper flow path wall 22a Lower surface 50 Lower sheet recess 51 Lower bottom surface protrusion 60 Upper sheet recess 61 Upper bottom surface protrusion 70 First lower mold 70a, 70b Mold protrusion 71 Second lower mold 71a Mold protrusion 80 First upper mold 80a Mold protrusion 81 Second upper mold 81a Mold protrusion 90 Upper surface protrusion M1 Lower material sheet M1a Upper surface M1b Lower surface M2 Upper material sheet M2a Lower surface M2b Upper surface

Claims (9)

A vapor chamber having a sealed space in which a working fluid is sealed,
The sealed space includes:
a plurality of steam flow paths through which the working fluid in a gaseous state flows;
a liquid flow path or a wick material provided in a flow path wall that defines the plurality of adjacent vapor flow paths, through which the working fluid in a liquid state flows;
is provided,
The liquid flow path or the wick material is provided only in a portion of the flow path wall in a thickness direction of the vapor chamber,
At least one of a recess and a protrusion is provided on at least a portion of an outer surface of the vapor chamber at a position overlapping the vapor flow path in a plan view,
The recess and the protrusion have a curved shape in a cross section perpendicular to a direction in which the steam flow path extends.
Vapor chamber. A vapor chamber having a sealed space in which a working fluid is sealed,
The sealed space includes:
a plurality of steam flow paths through which the working fluid in a gaseous state flows;
a liquid flow path or a wick material provided in a flow path wall that defines the plurality of adjacent vapor flow paths, through which the working fluid in a liquid state flows;
is provided,
The liquid flow path or the wick material is provided only in a portion of the flow path wall in a thickness direction of the vapor chamber,
At least a portion of an outer surface of the vapor chamber at a position overlapping the vapor flow path in a plan view is provided with a recess,
The recess is provided across the entire width of the steam flow path in a cross section perpendicular to a direction in which the steam flow path extends.
Vapor chamber. A vapor chamber having a sealed space in which a working fluid is sealed,
The sealed space includes:
a plurality of steam flow paths through which the working fluid in a gaseous state flows;
a liquid flow path or a wick material provided in a flow path wall that defines the plurality of adjacent vapor flow paths, through which the working fluid in a liquid state flows;
is provided,
The liquid flow path or the wick material is provided only in a portion of the flow path wall in a thickness direction of the vapor chamber,
At least a portion of an outer surface of the vapor chamber at a position overlapping the vapor flow path in a plan view is provided with a recess,
The recess is not provided at a position overlapping the liquid flow path or the wick material in a plan view.
Vapor chamber. A vapor chamber made of three or more layers of sheets and having a sealed space in which a working fluid is sealed,
The sealed space includes:
a plurality of steam flow paths through which the working fluid in a gaseous state flows;
A liquid flow path or a wick material provided between adjacent ones of the plurality of vapor flow paths, through which the working fluid in a liquid state flows;
is provided,
At least one of a recess and a protrusion is provided on at least a portion of an outer surface of the vapor chamber at a position overlapping the vapor flow path in a plan view,
the recess and the protrusion have a curved shape in a cross section perpendicular to a direction in which the steam flow path extends,
the sheet having the outer surface has a thickness at a position where the recess and the protrusion are present in a cross section perpendicular to a direction in which the steam flow path extends that is smaller than a thickness at a position where the recess and the protrusion are not present;
Vapor chamber. A vapor chamber made of three or more layers of sheets and having a sealed space in which a working fluid is sealed,
The sealed space includes:
a plurality of steam flow paths through which the working fluid in a gaseous state flows;
A liquid flow path or a wick material provided between adjacent ones of the plurality of vapor flow paths, through which the working fluid in a liquid state flows;
is provided,
At least a portion of an outer surface of the vapor chamber at a position overlapping the vapor flow path in a plan view is provided with a recess,
the recess is provided across the entire width of the steam flow path in a cross section perpendicular to a direction in which the steam flow path extends,
In the sheet having the outer surface, in a cross section perpendicular to a direction in which the steam flow path extends, a thickness at a position where the recess is present is smaller than a thickness at a position where the recess is not present.
Vapor chamber. A vapor chamber made of three or more layers of sheets and having a sealed space in which a working fluid is sealed,
The sealed space includes:
a plurality of steam flow paths through which the working fluid in a gaseous state flows;
A liquid flow path or a wick material provided between adjacent ones of the plurality of vapor flow paths, through which the working fluid in a liquid state flows;
is provided,
At least a portion of an outer surface of the vapor chamber at a position overlapping the vapor flow path in a plan view is provided with a recess,
The recess is not provided at a position overlapping the liquid flow path or the wick material in a plan view,
In the sheet having the outer surface, in a cross section perpendicular to a direction in which the steam flow path extends, a thickness at a position where the recess is present is smaller than a thickness at a position where the recess is not present.
Vapor chamber. a first sheet, a second sheet, and a third sheet disposed between the first sheet and the second sheet;
The wick material is provided only on the first sheet side of the third sheet.
The vapor chamber according to any one of claims 1 to 6. a first sheet, a second sheet, and a third sheet and a fourth sheet disposed between the first sheet and the second sheet;
The liquid flow path is provided in the fourth sheet.
The vapor chamber according to any one of claims 1 to 6. An electronic device comprising the vapor chamber according to any one of claims 1 to 8.

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