JP7586261B2 - Vapor chambers, electronic devices - Google Patents

Description

The present invention relates to a vapor chamber in which a working fluid sealed in an enclosed space moves while transporting heat.

Electronic components such as CPUs (Central Processing Units) are used in electronic devices such as personal computers and mobile terminals such as mobile phones and tablet terminals. The amount of heat generated by such electronic components tends to increase with improvements in information processing capabilities, so technology to cool them is becoming increasingly important.
Heat pipes are a well-known cooling method, in which a working fluid sealed inside the pipe transports and dissipates heat from a heat source to another location by utilizing the phase change of the working fluid, thereby cooling the heat source.

On the other hand, in recent years, these electronic devices have become significantly thinner, and a cooling means that is thinner than conventional heat pipes has become necessary. In response to this, vapor chambers have been proposed. Vapor chambers are also called sheet-type heat pipes, and are devices that apply the concept of heat transport by heat pipes to flat plate-shaped components. That is, in vapor chambers, a working fluid is sealed between opposing flat plates, and the phase change of this working fluid is used to transport and diffuse heat in the heat source to cool the heat source.

Such vapor chambers are placed inside electronic devices, and because many other components are placed inside electronic devices, there are often restrictions on where the vapor chamber can be placed. As a result, it is not always possible to provide a flow path for the working fluid in a straight line, and it is necessary to deal with the restrictions on placement by providing a flow path with a curved section that changes direction, as described in Patent Document 1, for example.

JP 2016-205693 A

However, as described in Patent Document 1, there was a problem in that it was difficult to increase the heat transport capacity in a vapor chamber where the direction of the flow path of the working fluid changes.

In view of the above problems, the present invention aims to provide a vapor chamber that can increase heat transport capacity even when it has a flow path that changes direction. It also provides an electronic device equipped with this vapor chamber.

After extensive research, the inventor discovered that in a vapor chamber having multiple vapor flow paths whose directions change, the flow resistance of the working fluid increases when the direction of the working fluid flow path changes, making it difficult for the vapor to reach the end of the flow path and resulting in insufficient heat transport. In addition, the inventor discovered that because the multiple vapor flow paths have different lengths, differences in flow resistance occur and the working fluid does not move in a balanced manner, so that when the difference in flow resistance becomes large, the heat transport capacity decreases and it may not be possible to achieve the expected performance. Based on these findings, the inventor completed the present invention. The present invention will be described below.

One aspect of the present invention is a vapor chamber in which a working fluid is sealed in an enclosed space, the enclosed space being provided with a condensate flow path, which is a flow path through which the working fluid moves in a condensed liquid state, and multiple steam flow paths, which have a flow path cross-sectional area larger than that of the condensate flow path, and through which the working fluid moves in a vapor and condensed liquid state, the vapor chamber having a straight section in which the multiple condensate flow paths and multiple steam flow paths extend linearly, and a curved section connected to the straight section, in which the extension direction of the multiple condensate flow paths and multiple steam flow paths changes, and the vapor flow path in the curved section is configured so that the flow path cross-sectional area of the vapor flow path in the curved section is larger than that of the vapor flow path in the straight section.

According to the present invention, the heat transport capacity can be increased even when the vapor chamber has a flow path whose direction changes.

FIG. 1( a ) is a perspective view of the vapor chamber 1 , and FIG. 1( b ) is an exploded perspective view of the vapor chamber 1 . FIG. 2 is a perspective view of the first sheet 10. As shown in FIG. FIG. 3 is a plan view of the first sheet 10. FIG. 4 is a cross section of the first sheet 10. 5(a) and 5(b) are other cross-sectional views of the first sheet 10. FIG. FIG. 6 is a partially enlarged plan view of the outer peripheral liquid flow path portion 14. As shown in FIG. FIG. 7 is a partially enlarged plan view of another example of the outer circumferential liquid flow path portion 14. In FIG. FIG. 8( a ) is a cross-sectional view focusing on the inner liquid flow path section 15 , and FIG. 8( b ) is a partially enlarged plan view of the inner liquid flow path section 15 . 9(a) to 9(c) are diagrams for explaining examples of the shape of the curved portion 18c. FIG. 10 is a diagram for explaining an example in which pillars 16a are provided in the steam flow passage groove 16. In FIG. FIG. 11A is a plan view focusing on the curved portion 18c, and FIG. 11B is a diagram showing the curved portion 18c in another example. FIG. 12 is a diagram showing a curved portion 18c in another example. FIG. 13 is a perspective view of the second sheet 20. As shown in FIG. FIG. 14 is a plan view of the second sheet 20. FIG. 15 is a cross section of the second sheet 20. FIG. 16 is another cross-section of the second sheet 20. FIG. 17 is a cross-sectional view of the vapor chamber 1. FIG. 18 is an enlarged view of a portion of FIG. FIG. 19 is another cross-sectional view of the vapor chamber 1. 20(a) to 20(c) are diagrams for explaining examples of the configuration of the condensate flow path. FIG. 21 is a diagram for explaining the condensate flow path 3 and the steam flow path 4. FIG. 22 is a perspective view illustrating an electronic device 40. As shown in FIG. FIG. 23 is a diagram illustrating the operation of the vapor chamber 1. FIG. 24 is a perspective view showing the exterior of the vapor chamber 201. FIG. 25 is an exploded perspective view of the vapor chamber 201. FIG. 26( a ) is a view of the third sheet 230 as viewed from one surface side, and FIG. 26( b ) is a view of the third sheet 230 as viewed from the other surface side. FIG. 27 is a cross section of the third sheet 230. FIG. 28 is another cross-section of the third sheet 230. FIG. 29 is a cross-sectional view of the vapor chamber 201. FIG. 30 is an enlarged view of a portion of FIG. FIG. 31 is another cross-sectional view of the vapor chamber 201.

Each embodiment will be described below with reference to the drawings. However, the present invention is not limited to these embodiments. In the drawings shown below, the size and proportions of components may be altered or exaggerated for ease of understanding. Also, for ease of viewing, illustrations of parts that are not necessary for explanation and repeated reference symbols may be omitted.

Figure 1(a) shows an external perspective view of the vapor chamber 1 according to the first embodiment, and Figure 1(b) shows an exploded perspective view of the vapor chamber 1. For convenience, these figures and the figures shown below also show arrows (x, y, z) that indicate mutually orthogonal directions as necessary. Here, the xy in-plane direction is the direction along the plate surface of the vapor chamber 1, which is flat, and the z direction is the thickness direction.

As can be seen from Figures 1(a) and 1(b), the vapor chamber 1 of this embodiment has a first sheet 10 and a second sheet 20. As will be described later, the first sheet 10 and the second sheet 20 are stacked and joined (diffusion bonding, brazing, etc.) to form a hollow space between the first sheet 10 and the second sheet 20, and the working fluid is sealed in this hollow space to form the sealed space 2 (see, for example, Figure 17).

In this embodiment, the first sheet 10 is a sheet-like member as a whole, and is L-shaped in a plan view. Fig. 2 shows a perspective view of the first sheet 10 as seen from the inner surface 10a side, and Fig. 3 shows a plan view of the first sheet 10 as seen from the inner surface 10a side. Fig. 4 shows a cut surface of the first sheet 10 when cut along IV-IV in Fig. 3.
The first sheet 10 has an inner surface 10a, an outer surface 10b opposite to the inner surface 10a, and a side surface 10c extending between the inner surface 10a and the outer surface 10b to form a thickness, and a pattern for a flow path through which the working fluid moves is formed on the inner surface 10a side. As described below, the inner surface 10a of the first sheet 10 and the inner surface 20a of the second sheet 20 are overlapped so as to face each other to form a hollow portion, into which the working fluid is sealed to form the sealed space 2.

The thickness of the first sheet 10 is not particularly limited, but is preferably 0.01 mm or more and 1.0 mm or less, and more preferably 0.05 mm or more and 0.2 mm or less. This increases the number of situations in which it can be used as a thin vapor chamber.

The first sheet 10 includes a main body 11 and an injection portion 12. The main body 11 is in the form of a sheet that forms a portion through which the working fluid moves, and in this embodiment, is L-shaped having a curved portion in a plan view.
The injection section 12 is a section where the working fluid is injected into the hollow section formed by the first sheet 10 and the second sheet 20, and in this embodiment, is a sheet-like shape that is rectangular in plan view and protrudes from the L-shaped main body 11 in plan view. In this embodiment, both the inner surface 10a side and the outer surface 10b side of the injection section 12 of the first sheet 10 are flat surfaces.

A structure for moving the working fluid is formed on the inner surface 10a side of the main body 11.
Specifically, this structure includes an outer periphery joining portion 13, an outer periphery liquid flow passage portion 14, an inner liquid flow passage portion 15, a steam flow passage groove 16, and a steam flow passage connecting groove 17 on the inner surface 10a side of the main body 11.

The outer peripheral joining portion 13 is a surface formed on the inner surface 10a side of the main body 11 along the outer periphery of the main body 11. This outer peripheral joining portion 13 is overlapped and joined (by diffusion bonding, brazing, etc.) to the outer peripheral joining portion 23 of the second sheet 20, thereby forming a hollow portion between the first sheet 10 and the second sheet 20, and a working fluid is sealed in this hollow portion to form the sealed space 2.
The width of the outer peripheral joint 13 shown by A ₁₀ in Figures 3 and 4 can be set as needed, but is preferably 0.05 mm to 5.0 mm at its narrowest. If the width is less than 0.05 mm, there is a risk that the joint area will be insufficient if the first sheet and the second sheet are misaligned when they are joined. If the width is more than 5.0 mm, there is a risk that the internal volume of the sealed space will be small, making it impossible to ensure sufficient steam flow paths and condensate flow paths.

The peripheral liquid flow path section 14 functions as a liquid flow path section and is a part that constitutes part of the condensed liquid flow path 3 (see, for example, FIG. 18), which is the flow path through which the working fluid passes when it is condensed and liquefied. FIG. 5(a) shows the part indicated by the arrow Va in FIG. 4, and FIG. 5(b) shows the cross-section taken along Vb-Vb in FIG. 3. The cross-sectional shape of the peripheral liquid flow path section 14 is shown in both figures. Also, FIG. 6 shows an enlarged plan view of the peripheral liquid flow path section 14 as seen from the direction indicated by the arrow VI in FIG. 5(a).

As can be seen from these figures, the peripheral liquid flow path section 14 is formed along the inside of the peripheral joint section 13 on the inner surface 10a of the main body 11, and is provided in a ring shape along the outer periphery of the sealed space 2. The peripheral liquid flow path section 14 is also formed with liquid flow path grooves 14a that are multiple grooves extending parallel to the direction in which the peripheral liquid flow path section 14 extends, and the multiple liquid flow path grooves 14a are arranged at intervals in a direction different from the direction in which the liquid flow path grooves 14a extend. Therefore, as can be seen from Figures 5(a) and 5(b), the peripheral liquid flow path section 14 has the liquid flow path grooves 14a that are recesses in the cross section, and the walls 14b that are protrusions between the liquid flow path grooves 14a, which are repeated recesses and projections.
Here, since the liquid flow passage groove 14a is a groove, its cross-sectional shape has a bottom and an opening on the opposite side facing the bottom.

By providing multiple liquid flow grooves 14a in this way, the depth and width of each liquid flow groove 14a can be reduced, and the flow cross-sectional area of the condensate flow path 3 (see FIG. 18, for example) can be reduced, making it possible to utilize a large capillary force. On the other hand, by providing multiple liquid flow grooves 14a, the total internal volume of the condensate flow path 3 as a whole can be ensured to be an appropriate size, allowing the condensate to flow at the required flow rate.

Furthermore, in the outer peripheral liquid flow passage portion 14, as can be seen from FIG. 6, adjacent liquid flow passage grooves 14a are connected by communication openings 14c provided at intervals in the wall 14b. This promotes equalization of the amount of condensed liquid between the multiple liquid flow passage grooves 14a, allowing the condensed liquid to flow efficiently. In addition, the communication openings 14c provided in the wall 14b adjacent to the steam flow passage groove 16 that forms the steam flow passage 4 connect the steam flow passage 4 and the condensed liquid flow passage 3. Therefore, by providing the communication openings 14c, the condensed liquid generated in the steam flow passage 4 can be smoothly moved to the condensed liquid flow passage 3, and the steam generated in the condensed liquid flow passage 3 can also be smoothly moved to the steam flow passage 4, which also makes it possible to promote smooth movement of the working fluid.

In this embodiment, the communication openings 14c are arranged so as to face each other at the same position in the direction in which the liquid flow channel 14a extends, sandwiching the liquid flow channel 14a as shown in Fig. 6. However, this is not limited to this, and the communication openings 14c may be arranged at different positions in the direction in which the liquid flow channel 14a extends, sandwiching the liquid flow channel 14a as shown in Fig. 7, for example. That is, in this case, the communication openings 14c are arranged offset in the direction in which the liquid flow channel 14a extends.
By providing the communication opening 14c in this offset manner, when viewed from the working fluid flowing through the condensate flow path 3, the communication opening 14c does not appear on both sides at the same time, and even if the communication opening 14c appears, the wall 14b always exists on at least one side. Therefore, capillary force can be obtained continuously. From this viewpoint, forming the communication opening 14c in an offset manner can maintain a high capillary force acting on the working fluid, allowing the condensate to flow smoothly.

The peripheral liquid flow path section 14 having the above-mentioned configuration preferably further has the following configuration.
The width of the outer peripheral liquid flow passage portion 14 shown by _B10 in Figures 3, 4, 5(a) and 5(b) can be set appropriately based on the size of the entire vapor chamber, but is preferably 0.03 mm or more and 2 mm or less. If the width is less than 0.03 mm, there is a risk that the amount of liquid flowing on the outside will be insufficient. Also, if the width exceeds 2 mm, there is a risk that there will not be enough space for the inner condensate flow passage and vapor flow passage.

The width of the liquid flow passage groove 14a, indicated by _C1 in FIG. 5(a) and FIG. 6, is preferably 10 μm or more and 300 μm or less.
In addition, the depth of the liquid flow path groove 14a indicated by D in Figures 5(a) and 5(b) is preferably 5 µm or more and 200 µm or less. This allows the capillary force of the liquid flow path required for the condensate to flow to be fully exerted. Here, the depth D of the liquid flow path groove is preferably smaller than the remaining sheet thickness obtained by subtracting the depth D of the groove from the thickness of the first sheet 10. This makes it possible to more reliably prevent the sheet from breaking when the working fluid freezes.
From the viewpoint of exerting a stronger capillary force in the flow channel, the aspect ratio (length-to-length ratio) in the flow channel cross section, which is expressed by the value obtained by dividing _C1 by D, is preferably greater than 1.0 or less than 1.0. Among these, from the viewpoint of ease of manufacture, it is preferable that C1 is greater than D, and the aspect ratio is preferably greater than 1.3.

5(a) and ₆ , the width of the wall 14b is preferably 20 μm or more and 300 μm or less. If the width is less than 20 μm, the wall 14b is easily broken due to repeated freezing and melting of the working fluid, and if the width is more than 300 μm, the width of the communication opening 14c becomes too large, which may hinder smooth communication of the working fluid with the adjacent condensate flow passage 3.

The size of the communication opening 14c along the direction in which the liquid flow passage groove 14a extends, as indicated by _C3 in FIG. 6, is preferably 20 μm or more and 180 μm or less.
Moreover, the pitch between adjacent communication openings 14c in the direction in which the liquid flow passage groove 14a extends, indicated by _C4 in FIG. 6, is preferably 300 μm or more and 2700 μm or less.

In this embodiment, the cross-sectional shape of the liquid flow path groove 14a is semi-elliptical, but is not limited to this and may be a square, rectangle, trapezoid or other quadrangle, a triangle, a semicircle, a semicircle with a bottom, a semi-ellipse with a bottom, etc.

It is also preferable that the liquid flow path groove 14a is formed continuously along the edge of the sealed space. In other words, it is preferable that the liquid flow path groove 14a extends in an annular shape around the entire circumference without being interrupted by other components. This reduces factors that hinder the movement of the condensate, allowing the condensate to move smoothly.

In this embodiment, a peripheral liquid flow path section 14 is provided, but this is not essential and may be omitted depending on the shape of the vapor chamber, the relationship with the device to which the vapor chamber is applied, and the usage environment. In this embodiment, the peripheral part of the sealed space can be configured as a steam flow path to transport heat to the peripheral part of the vapor chamber by steam, which may result in higher thermal uniformity.

Returning to Figures 2 to 4, the inner liquid flow path section 15 will now be described. The inner liquid flow path section 15 also functions as a liquid flow path section, and is a part that constitutes part of the condensed liquid flow path 3 through which the working fluid passes when it is condensed and liquefied. Figure 8(a) shows the part indicated by VIIIa in Figure 4. This figure also shows the cross-sectional shape of the inner liquid flow path section 15. Figure 8(b) shows an enlarged plan view of the inner liquid flow path section 15 as viewed from the direction indicated by arrow VIIIb in Figure 8(a).

As can be seen from these figures, the inner liquid flow path section 15 is formed inside the ring of the annular outer peripheral liquid flow path section 14 (or the outer peripheral joint section 13) on the inner surface 10a of the main body 11. As can be seen from Figures 2 and 3, the inner liquid flow path section 15 in this embodiment is a convex ridge extending with a curved section, and is arranged at intervals in a direction different from the extension direction of multiple (five in this embodiment) inner liquid flow path sections 15 and is disposed between the steam flow path grooves 16.
Each inner liquid flow path section 15 is formed with liquid flow path grooves 15a which are grooves parallel to the direction in which the inner liquid flow path section 15 extends, and a plurality of liquid flow path grooves 15a are arranged at predetermined intervals in a direction different from the direction in which the liquid flow path grooves 15a extend. Therefore, as can be seen from Figures 4 and 8(a), in the cross section of the inner liquid flow path section 15, the liquid flow path grooves 15a which are recesses and the walls 15b which are protrusions between the liquid flow path grooves 15a are formed in a repeated irregular shape.
Here, since the liquid flow passage groove 15a is a groove, its cross-sectional shape has a bottom and an opening on the opposite side facing the bottom.

By providing multiple liquid flow grooves 15a in this way, the depth and width of each liquid flow groove 15a can be reduced, and the flow cross-sectional area of the condensate flow path 3 (see FIG. 18, for example) can be reduced, making it possible to utilize a large capillary force. On the other hand, by providing multiple liquid flow grooves 15a, the total internal volume of the condensate flow path 3 as a whole can be ensured to be an appropriate size, allowing the condensate to flow at the required flow rate.

Furthermore, as can be seen from FIG. 8(b), in the inner liquid flow passage section 15, the adjacent liquid flow passage grooves 15a are connected to each other by the communication openings 15c provided at intervals in the wall 15b in the same manner as in FIG. 6 following the example of the outer peripheral liquid flow passage section 14. This promotes equalization of the amount of condensed liquid between the multiple liquid flow passage grooves 15a, allowing the condensed liquid to flow efficiently. In addition, the communication openings 15c provided in the wall 15b adjacent to the steam flow passage groove 16 that forms the steam flow passage 4 communicate the steam flow passage 4 and the condensed liquid flow passage 3. Therefore, by configuring the communication openings 15c as described later, the condensed liquid generated in the steam flow passage 4 can be smoothly moved to the condensed liquid flow passage 3, and the steam generated in the condensed liquid flow passage can be smoothly moved to the steam flow passage 4, which also promotes the smooth movement of the working fluid.

Also in the inner liquid flow path section 15, following the example of FIG. 7, the communication openings 15c may be arranged at different positions in the extension direction of one liquid flow path groove 15a, sandwiching the groove.
By providing the communication openings 15c in this offset manner, when viewed from the working fluid moving through the condensate flow path 3, the communication openings 15c do not appear on both sides at the same time, and even if the communication openings 15c appear, the wall 15b always exists on at least one side. Therefore, the capillary force can be obtained continuously. From this viewpoint, by forming the communication openings 15c in an offset manner, the capillary force acting on the working fluid can be kept high, and the working fluid can move more smoothly.

The inner liquid flow path section 15 having the above-mentioned configuration preferably further has the following configuration.
The width of the inner liquid flow path section 15 indicated by _E10 in Figures 3, 4 and 8(a) is preferably 100 µm or more and 2000 µm or less. The pitch of the multiple inner liquid flow path sections 15 is preferably 200 µm or more and 4000 µm or less. This sufficiently reduces the flow path resistance of the steam flow path, and allows a good balance between the movement of the working fluid in the steam flow path and the movement of the working fluid due to the action of capillary force in the condensate flow path.

The width of the liquid flow passage groove 15a, indicated by _F1 in Figs. 8(a) and 8(b), is preferably 10 µm or more and 300 µm or less.
In addition, the depth of the groove indicated by G in Fig. 8(a) is preferably 5 µm or more and 200 µm or less. This allows the capillary force of the condensate flow path required for the movement of the condensate to be fully exerted. Here, the groove depth G is preferably smaller than the remaining sheet thickness obtained by subtracting the groove depth G from the thickness of the first sheet 10. This makes it possible to more reliably prevent the sheet from breaking when the working fluid freezes.
From the viewpoint of exerting a stronger capillary force in the flow channel, the aspect ratio (length-to-length ratio) in the flow channel cross section, which is expressed by the value obtained by dividing _F1 by G, is preferably greater than 1.0 or less than 1.0. Among these, from the viewpoint of manufacturing, it is preferable that F1 is greater than G, and the aspect ratio is preferably greater than 1.3.

8(a) and 8(b), the width of the wall 15b is preferably 20 μm or more and 300 μm or less. If the width is less than 20 μm, the wall 15b is easily _broken due to repeated freezing and melting of the working fluid, and if the width is more than 300 μm, the width of the communication opening 15c becomes too large, which may hinder smooth communication between the condensate flow paths 3.

Regarding the communication opening 15c, the size of the communication opening along the direction in which the liquid flow passage groove 15a extends, indicated by _F3 in FIG. 8(b), is preferably 20 μm or more and 180 μm or less.
Furthermore, the pitch between adjacent communication openings 15c in the direction in which liquid flow passage groove 15a extends, indicated by _F4 in FIG. 8B, is preferably 300 μm or more and 2700 μm or less.

In addition, in this embodiment, the cross-sectional shape of the liquid flow path groove 15a is semi-elliptical, but it is not limited to this and may be a square, rectangle, trapezoid or other quadrangle, a triangle, a semicircle, a shape with a semicircle at the bottom, a semi-ellipse at the bottom, etc.

Next, the steam flow groove 16 will be described. The steam flow groove 16 is a portion through which the working fluid in the form of vapor and condensed liquid moves, and constitutes part of the steam flow path 4. Figure 3 shows the shape of the steam flow groove 16 in a plan view, and Figure 4 shows the cross-sectional shape of the steam flow groove 16.

As can be seen from these figures, the steam flow path grooves 16 are formed on the inner surface 10a of the main body 11, on the inside of the ring of the annular outer peripheral liquid flow path section 14. More specifically, the steam flow path grooves 16 in this embodiment are formed between adjacent inner liquid flow path sections 15 and between the outer peripheral liquid flow path section 14 and the inner liquid flow path section 15, and are grooves that extend with curved portions. A plurality of steam flow path grooves 16 (six in this embodiment) are arranged in a direction different from the direction of extension. Therefore, as can be seen from Fig. 4, the first sheet 10 has a shape in which projections and recesses are repeated, with the inner liquid flow path sections 15 as projections and the steam flow path grooves 16 as recesses.
Here, since the steam flow passage groove 16 is a groove, its cross-sectional shape has a bottom and an opening located on the opposite side facing the bottom.

The steam flow passage groove 16 may be configured so that when the steam flow passage 4 is formed in combination with the steam flow passage groove 26 of the second sheet 20, the working fluid moves through the steam flow passage 4. Therefore, it is preferable that the steam flow passage groove 16 further has the following configuration.
The width of the vapor flow passage groove 16 indicated by _H10 in Figs. 3 and 4 is formed to be at least larger than the widths _C1 and _F1 of the liquid flow passage grooves 14a and 15a, and is preferably 100 µm or more and 2000 µm or less.
On the other hand, the depth of the vapor flow passage groove 16 indicated by _I10 in FIG. 4 is formed to be at least greater than the depths D and G of the liquid flow passage grooves 14a and 15a, and is preferably 10 μm or more and 300 μm or less.
This ensures stable movement of the working fluid when the steam flow path is formed, and by making the flow path cross-sectional area of the steam flow path groove larger than that of the liquid flow path groove, steam, which has a larger volume than condensed liquid due to the nature of the working fluid, can be moved smoothly.

Here, the steam flow channel groove 16 is preferably configured so that the steam flow channel 4 has a flat shape in which the width is greater than the height (size in the thickness direction) when combined with the second sheet 20 as described later to form the steam flow channel 4. Therefore, the aspect ratio, which is the value obtained by dividing _H10 by _I10 , is preferably 4.0 or more, and more preferably 8.0 or more.

In this embodiment, the cross-sectional shape of the steam flow channel groove 16 is semi-elliptical, but it is not limited to this and may be a square, rectangle, trapezoid or other quadrangle, triangle, semicircle, circular at the bottom, semi-elliptical at the bottom, etc.

The steam flow passage communication groove 17 is a groove that communicates the multiple steam flow passage grooves 16 and, in combination with the steam flow passage communication groove 27 of the second sheet 20, forms a flow passage that communicates the multiple steam flow passages 4 formed by the steam flow passage grooves 16 at their ends. This allows smooth movement of the working fluid generated in the steam flow passage 4 in the extension direction of the inner liquid flow passage section 15.
This also makes it possible to equalize the working fluid in the steam flow path 4, transport the steam over a wider area, and efficiently utilize the condensate flow path 3 formed by many liquid flow path grooves 14a and 15a.

As can be seen from Figures 2 and 3, the steam flow passage communication groove 17 in this embodiment is formed between both ends in the direction in which the inner liquid flow passage section 15 extends and both ends in the direction in which the steam flow passage groove 16 extends, and the outer circumferential liquid flow passage section 14. Figure 5(b) shows a cross section perpendicular to the communication direction of the steam flow passage communication groove 17. Note that the boundary between the steam flow passage communication groove 17 and the steam flow passage groove 16 is not necessarily formed by a boundary due to its shape, so for ease of understanding, the boundary is shown by a dotted line in Figures 2 and 3.

The steam flow passage communication groove 17 may have any shape as long as it can communicate with the adjacent steam flow passage grooves 16, and may have, for example, the following configuration.
The width of the steam flow passage communication groove 17 indicated by J ₁₀ in FIG. 3 and FIG. 5( b ) is preferably 100 μm or more and 1000 μm or less.
₅ (b) , the depth of the steam flow passage communication groove 17 is preferably 10 μm or more and 300 μm or less, and is preferably the same as the depth I ₁₀ of the steam flow passage groove 16. This makes it easier to manufacture the first sheet 10.

In this embodiment, the cross-sectional shape of the steam flow path communication groove 17 is semi-elliptical, but it is not limited to this and may be a square, rectangle, trapezoid or other quadrangle, a triangle, a semicircle, a semicircle with a bottom, a semi-ellipse with a bottom, etc.

In this embodiment, the first sheet 10 has curved portions 18c which are portions where the extending directions of the liquid flow passage grooves 14a (outer peripheral liquid flow passage section 14), the liquid flow passage grooves 15a (inner liquid flow passage section 15), and the steam flow passage grooves 16 change. That is, the first sheet 10 has linear portions 18a where the liquid flow passage grooves 14a (outer peripheral liquid flow passage section 14), the liquid flow passage grooves 15a (inner liquid flow passage section 15), and the steam flow passage grooves 16 extend linearly in the x direction, linear portions 18b where the liquid flow passage grooves 14a (outer peripheral liquid flow passage section 14), the liquid flow passage grooves 15a (inner liquid flow passage section 15), and the steam flow passage grooves 16 extend linearly in the y direction, and curved portions 18c which connect the liquid flow passage grooves 14a (outer peripheral liquid flow passage section 14), the liquid flow passage grooves 15a (inner liquid flow passage section 15), and the steam flow passage grooves 16 in the linear portions 18a and 18b. Therefore, one end of the curved portion 18c is connected to one straight portion 18a and the other end is connected to the other straight portion 18b, and the liquid flow path groove 14a (outer peripheral liquid flow path portion 14), the liquid flow path groove 15a (inner liquid flow path portion 15), and the steam flow path groove 16 are curved so that the flow changes direction from the x direction to the y direction and from the y direction to the x direction.
Here, the boundary between the straight portion and the curved portion may be the point where the flow direction starts to change in each groove. The same can be considered below. Figure 11(a) shows an enlarged view of the curved portion 18c in Figure 3.

As can be clearly seen from Figures 3 and 11(a), in this embodiment, the width of the steam flow path groove 16 is made larger in the curved portion 18c than in the straight portions 18a and 18b. This allows the flow resistance to be reduced in the curved portion 18c, where the flow resistance increases due to the curvature of the flow path, and reduces the flow resistance throughout the vapor chamber, allowing the working fluid to move more smoothly and increasing the heat transport capacity. In this case, the width may be constant within the range of the curved portion 18c. This allows the flow resistance of the working fluid to be kept low.

There is no particular limitation on the means for making the width of the steam flow passage groove 16 in the curved portion 18c larger than the width of the steam flow passage groove 16 in the straight portion 18a and the straight portion 18b. In this embodiment, this is achieved by making the width of the outer peripheral liquid flow passage section 14 and the inner liquid flow passage section 15 in the portion belonging to the curved portion 18c smaller than the width of the outer peripheral liquid flow passage section 14 and the inner liquid flow passage section 15 in the portion belonging to the straight portion 18a and the straight portion 18b. In this case, the width of the liquid flow passage groove 14a of the outer peripheral liquid flow passage section 14 and the liquid flow passage groove 15a of the inner liquid flow passage section 15 in this portion may be reduced, or the number of the liquid flow passage grooves 14a and the liquid flow passage grooves 15a may be reduced.

In addition, a means may be applied in which the width of the outer peripheral liquid flow path section 14 and the inner liquid flow path section 15 belonging to the curved section 18c are kept the same as the width of the outer peripheral liquid flow path section 14 and the inner liquid flow path section 15 belonging to the straight section 18a and the straight section 18b, and the width of the steam flow path groove 16 in the curved section 18c is made larger than the width of the steam flow path groove 16 in the straight section 18a and the straight section 18b. As a specific example, the explanatory diagrams are shown in Figures 9(a) to 9(c).

9A to 9C are explanatory views focusing on one steam flow groove 16. The other multiple steam flow grooves 16 can be considered in the same manner.
The meanings of the symbols shown in FIGS. 9(a) to 9(c) are as follows.
At the curved portion 18c of the steam flow passage groove 16, the inner wall w _in of the curve has a radius of curvature r _in and is an arc shape with its center O ₁ .
At the curved portion 18c, the steam flow channel groove 16 has an outer wall w _out of the curve with a radius of curvature r _out and has an arc shape with its center O ₁ , O ₂ , or O ₃ depending on the configuration, as will be described later.
The steam flow passage groove 16 has a width α at the straight portion 18a and the straight portion 18b, and the width of the steam flow passage groove 16 is increased to β at the curved portion 18c (α<β).
The curve shown by the dotted line is an imaginary line in the case where the width of the steam flow passage groove 16 is maintained at α even at the curved portion 18c, and the radius of curvature in this case is _rc and the shape is an arc with its center _O1 .
Here, the radius of the curvature can be determined by considering a circle passing through three points in total: two points where the direction of the walls (inner wall, outer wall) in the curved portion starts to change, and one point in the middle of these two points. When the curvature is considered to be a part of a circle or an ellipse, as shown in Fig. 9 and Fig. 11, the circle is regarded as the "inside" of the curved portion, the center side of the ellipse (i.e., the _O1 , _O2 , _O3 side) is regarded as the "inside" of the curved portion, and the opposite side of the circle and the center side of the ellipse is regarded as the "outside" of the curve. The shape of the curve is not limited to a shape like a part of a perfect circle, but may be a shape like a part of an ellipse, or a shape in which some of the steam flow grooves arranged in the curved portion are straight lines. The shapes of the curved portions below can be considered in the same manner.

In the example of FIG. 9(a), the radius of curvature r _out of the outer wall w _out of the steam flow path groove 16 at the curved portion 18c is greater than the radius of curvature r _c (r _out >r _c ), and the center is O ₁ .

In the example of Figure 9 (b), in the curved portion 18c, the radius of curvature r _out of the outer wall w _out of the steam flow path groove 16 is the same as the radius of curvature _rc (r _out = _rc ), but its center is at _O2, which is shifted toward the steam flow path groove 16 side from _O1 .

In the example of Figure 9 (c), in the curved portion 18c, the radius of curvature r _out of the outer wall w _out of the steam flow path groove 16 is smaller than the radius of curvature r _in and the radius of curvature r _c (r _out < r _in < r _c ), and its center is at O ₃ , which is shifted toward the steam flow path groove 16 side from O ₁ .

9(a) and 9(b), the straight portion and the arc portion are connected by one bent portion in the outer wall w _out . However, the present invention is not limited to this, and the bent portion may be a number of small bent portions or a curved portion, so that the direction of the bent portion changes gradually and smoothly.

The width of the steam flow path groove 16 in the curved portion 18c is not particularly limited as long as it is possible to reduce the flow resistance, but it is preferable that the width is 10% to 100% larger than that of the straight portions 18a and 18b. If it is less than 10%, there is a risk that the flow resistance will not be sufficiently reduced. On the other hand, if the width of the steam flow path groove is increased by more than 100% in the curved portion 18c compared to the straight portions 18a and 18b, there is a risk that the flow resistance of the straight portions will increase.

In addition, although the above description focuses on the width of the steam flow groove, instead of or in addition to this, the depth of the steam flow groove 16 in the curved portion 18c may be made deeper than the straight portion 18a and the straight portion 18b. In a configuration in which the depth is changed, the expansion in the planar direction (xy direction) is suppressed, so that it is possible to secure many areas for arranging the condensate flow path and improve the heat transport capacity, or to make the outer periphery joint wider, thereby improving the reliability of the pressure resistance. In this case, the depth may be constant within the range of the curved portion 18c. This makes it possible to keep the flow resistance of the working fluid low.
The difference in depth is not particularly limited as long as it is possible to reduce the flow resistance, but it is preferable that the steam flow channel grooves are 10% or more deeper in the curved portion than in the straight portion. If it is less than 10%, there is a risk that the flow resistance will not be sufficiently reduced.

10, the vapor flow passage groove 16 in the curved portion 18c may have a plurality of pillars 16a arranged to stand up from the bottom at the center in the width direction. These pillars serve as pillars supporting the first sheet 10 and the second sheet 20 of the vapor chamber 1. As a result, the width of the vapor flow passage groove in the curved portion 18c is increased, which suppresses a decrease in strength caused by the increased width of the vapor flow passage. Specifically, this prevents the vapor flow passage from collapsing due to insufficient strength when joining or reducing pressure when combining the first sheet 10 and the second sheet 20 to form the vapor chamber 1, and when incorporating the vapor chamber into an electronic device.
From this viewpoint, as shown in Fig. 10, pillars 16a can be provided for the long steam flow path groove 16. However, this is not limited to the above, and pillars 16a may be provided for any other steam flow path groove 16 as necessary, or pillars 16a may be provided for all the steam flow path grooves 16.

In this embodiment, as shown in FIG. 11(a), the width of the steam flow groove 16 is changed in a step at the connection between the curved and straight sections. In contrast, in the example shown in FIG. 11(b), the width of the steam flow groove 16 is changed gradually at the connection between the curved and straight sections by a tapered inclined surface. This makes it possible to prevent vortexes from occurring when the working fluid passes through the connection, and also makes it possible to keep flow resistance low.

In the above embodiment, the widths of the plurality of steam flow passage grooves 16 are the same in the curved portion 18c. However, the present invention is not limited to this and the widths of the steam flow passage grooves may be changed.
In this case, for example, the groove width of the steam flow path groove having a large radius of curvature may be made larger than the groove width of the steam flow path groove having a small radius of curvature, thereby reducing the flow resistance of the steam flow path having a large radius of curvature, which is a long distance traveled by the steam.
In addition, the groove width of the steam flow path groove having a small radius of curvature may be made larger than the groove width of the steam flow path groove having a large radius of curvature, thereby reducing the flow resistance of the steam flow path at the curved portion due to the small radius.
Furthermore, the groove width of the steam flow passage groove having a large radius and the groove width of the steam flow passage groove having a small radius may be made larger for the steam flow passage disposed in the center.
By using the above-mentioned means, it is possible to further reduce the difference in flow resistance between a plurality of steam flow passage grooves, improve the balance of the movement of the working fluid, and increase the heat transport capacity.

In addition to the above, the first sheet 10 may have the following configuration.
3, in the curved portion 18c of this embodiment, the liquid flow path grooves 14a, 15a, and the steam flow path groove 16 are configured such that, in the direction in which these flow path grooves are arranged, the radius of curvature of the steam flow path on one side of the arrangement direction is larger than the radius of curvature of the steam flow path on the other side of the arrangement direction.

In this embodiment, each of the grooves is curved to draw a concentric arc. However, this is not limited to this, and the center position of the arc may be offset. Furthermore, the curved portion 18c is configured so that the radius of each flow groove increases as the length of each flow groove increases.

When multiple curved flow paths are arranged in a vapor chamber, the flow path length is shorter on the inside and longer on the outside, resulting in a large difference in flow resistance between the inside and outside. This difference in flow resistance causes the working fluid movement in the vapor chamber to become unbalanced, which is one of the reasons why sufficient heat transport capacity cannot be achieved. In contrast, by using a configuration with the above-mentioned radius of curvature, it is possible to reduce the difference in flow resistance between the inside and outside, especially in the vapor flow path groove 16. This improves the balance of the working fluid movement and also increases the heat transport capacity.

However, this is not limited to the above, and the radius of curvature of the multiple steam flow path grooves 16 in the curved portion 18c may be the same, as shown in FIG. 12.

In addition, in the curved portion 18c, the communication openings 14c and 15c (see FIG. 6 and FIG. 8(b)) provided in the walls 14b and 15b separating the liquid flow grooves 14a and 15a from the vapor flow groove 16 can be configured to have a pitch different from that of the other portions (straight portion 18a and straight portion 18b). The pitch of the communication openings in the curved portion may be larger or smaller than the pitch of the curved portions in the straight portion. The form to be adopted can be determined by comprehensively judging the form that can reduce the flow resistance, taking into consideration the effects of the overall shape of the vapor chamber, the position of the heat source, etc. Alternatively, the curved portion 18c does not need to have the communication openings 14c and 15c provided in the walls 14b and 15b separating the liquid flow grooves 14a and 15c from the vapor flow groove 16.
In a configuration in which the pitch of the communication openings in the curved portion is larger than the pitch of the communication openings in the straight portion, the working fluid flowing through the steam flow groove 16 (steam flow path 4) can be prevented from entering the communication openings 14c and 15c at the curved portion 18c. In the curved portion 18c, the working fluid moving through the steam flow groove 16 (steam flow path 4) is forced to flow directly into the communication openings 14c and 15c due to its flow direction, so that the steam tends to enter the condensate flow path 3 and the flow resistance tends to increase due to the unevenness of the communication openings 14c and 15c. In contrast, by increasing the pitch of the communication openings 14c and 15c that contact the steam flow groove 16 at the curved portion 18c or eliminating the communication openings 14c and 15c that contact the steam flow groove 16, it is possible to suppress such an increase in flow resistance, and the difference in flow resistance for each steam flow groove 16 (steam flow path 4) can be further reduced, improving the balance of the movement of the working fluid and increasing the heat transport capacity.
On the other hand, in a configuration in which the pitch of the communication openings in the curved portion is smaller than the pitch of the communication openings in the straight portion, the steam flowing through the steam flow passage groove (steam flow passage) has more opportunities to strongly hit the wall surface in the curved portion, so that condensation tends to occur easily. In this case, by making the pitch of the communication openings in the curved portion smaller than the pitch of the communication openings in the straight portion, the number of communication openings can be increased, and the condensate can be smoothly introduced into the liquid flow passage groove (condensate flow passage), making it possible to prevent the steam flow passage from being blocked by the condensate. This can prevent an increase in flow resistance, further reduce the difference in flow resistance between the steam flow passage grooves (steam flow passages), improve the balance of the movement of the working fluid, and increase the heat transport capacity.

Next, the second sheet 20 will be described. In this embodiment, the second sheet 20 is also a sheet-like member as a whole, and is curved in an L-shape in a plan view. Fig. 13 shows a perspective view of the second sheet 20 seen from the inner surface 20a side, and Fig. 14 shows a plan view of the second sheet 20 seen from the inner surface 20a side. Fig. 15 shows a cut surface of the second sheet 20 when cut along XIII-XIII in Fig. 14. Fig. 16 shows a cut surface of the second sheet 20 when cut along XIV-XIV in Fig. 14.
The second sheet 20 has an inner surface 20a, an outer surface 20b opposite to the inner surface 20a, and a side surface 20c that spans the inner surface 20a and the outer surface 20b to form a thickness, and a pattern through which the working fluid moves is formed on the inner surface 20a side. As described later, the inner surface 20a of the second sheet 20 and the inner surface 10a of the first sheet 10 are overlapped and joined so as to face each other to form a hollow portion, in which the working fluid is sealed to form the sealed space 2.

The thickness of the second sheet 20 is not particularly limited, but is preferably 0.01 mm or more and 1.0 mm or less, and more preferably 0.05 mm or more and 0.2 mm or less. This increases the number of situations in which it can be used as a thin vapor chamber.

The second sheet 20 includes a main body 21 and an injection portion 22. The main body 21 is in the form of a sheet that forms a portion through which the working fluid moves, and in this embodiment, is L-shaped having a curved portion in a plan view.
The injection section 22 is a section where the working fluid is injected into the hollow section formed by the first sheet 10 and the second sheet 20, and in this embodiment, is a sheet-like shape that is rectangular in plan view and protrudes from the L-shaped main body 21 in plan view. In this embodiment, an injection groove 22a is formed on the inner surface 20a side of the injection section 22 of the second sheet 20, and communicates from a side surface 20c of the second sheet 20 to the inside of the main body 21 (the hollow section, the section that is to become the sealed space 2).

A structure for moving the working fluid is formed on the inner surface 20a of the main body 21. Specifically, the inner surface 20a of the main body 21 is provided with an outer periphery joint 23, an outer periphery liquid flow path section 24, an inner liquid flow path section 25, a steam flow path groove 26, and a steam flow path communication groove 27.

The outer peripheral joining portion 23 is a surface formed on the inner surface 20a side of the main body 21 along the outer periphery of the main body 21. This outer peripheral joining portion 23 overlaps and is joined (by diffusion bonding, brazing, etc.) to the outer peripheral joining portion 13 of the first sheet 10, thereby forming a hollow portion between the first sheet 10 and the second sheet 20, and a working fluid is sealed in this hollow portion to form the sealed space 2.
The width of the outer peripheral joint portion 23 indicated by _A20 in Figs. 14, 15 and 16 is preferably the same as the width _A10 of the outer peripheral joint portion 13 of the main body 11 described above.

The outer peripheral liquid flow path section 24 functions as a liquid flow path section and constitutes part of the condensed liquid flow path 3 (see, for example, FIG. 18), which is the flow path through which the working fluid passes when it is condensed and liquefied.

The peripheral liquid flow path portion 24 is formed along the inside of the peripheral joint portion 23 on the inner surface 20a of the main body 21, and is formed so as to form a ring along the outer periphery of the sealed space 2. In this embodiment, the peripheral liquid flow path portion 24 of the second sheet 20 is a flat surface and is flush with the peripheral joint portion 23 before being joined to the first sheet 10, as can be seen from Figures 15 and 16. This closes the openings of at least some of the liquid flow path grooves 14a of the first sheet 10 described above, thereby forming the condensate liquid flow paths 3. A detailed embodiment of the combination of the first sheet 10 and the second sheet 20 will be described later.
In addition, since the outer peripheral bonding portion 23 and the outer peripheral liquid flow path portion 24 are flush with each other in this manner in the second sheet 20, there is no structural boundary line that distinguishes the two. However, for ease of understanding, the boundary between the two is represented by a dotted line in Figures 13 and 14.

The outer circumferential liquid flow path section 24 preferably has the following configuration.
14, 15, and 16 is not particularly limited, and may be the same as or different from the width _B10 of the peripheral liquid flow path portion 14 of the first sheet 10. In this embodiment, the width _B10 and _{the width B20 are} the same.
When the width B ₂₀ is made smaller than the width B ₁₀ , the openings of the liquid flow path grooves 14a are not closed by the peripheral liquid flow path portion 24 in at least a part of the peripheral liquid flow path portion 14, and the condensed liquid can easily enter from these openings and the steam can easily exit from these openings, thereby enabling the working fluid to move more smoothly.

In this embodiment, the peripheral liquid flow path portion 24 of the second sheet 20 is configured to have a flat surface, but this is not limited thereto, and liquid flow path grooves may be provided in the same manner as the peripheral liquid flow path portion 14. In this case, the liquid flow path grooves of the first sheet and the liquid flow path grooves of the second sheet are overlapped to form the condensed liquid flow path 3.

In addition, as explained in the first sheet in this embodiment, the peripheral liquid flow path section 24 does not necessarily have to be provided, and the embodiment may be one in which the peripheral liquid flow path section 24 is not provided.

Next, we will explain the inner liquid flow path section 25. The inner liquid flow path section 25 is also a liquid flow path section and is one part that constitutes the condensate liquid flow path 3.

13 to 16 , the inner liquid flow path section 25 is formed on the inner surface 20a of the main body 21, inside the annular ring of the outer peripheral liquid flow path section 24. The inner liquid flow path section 15 in this embodiment is a convex ridge extending with a curved portion, and is arranged at intervals in a direction different from the direction in which the multiple (five in this embodiment) inner liquid flow path sections 25 extend, and is disposed between the steam flow path grooves 26.
In this embodiment, each inner liquid flow path portion 25 is formed so that its surface on the inner surface 20a side is flat before being joined to the first sheet 10. As a result, the openings of at least some of the liquid flow path grooves 15a of the first sheet 10 described above are closed to form the condensate liquid flow paths 3.
When no grooves for forming the condensate liquid flow paths 3 are formed in the inner liquid flow path section 25 as in this embodiment, the thickness of the second sheet 20 is preferably equal to or greater than the thickness obtained by subtracting the depth G of the liquid flow path grooves 15a (see FIG. 8(a)) from the thickness of the first sheet 10. This makes it possible to prevent breakage (tears) on the second sheet side in the vapor chamber.

In this embodiment, the inner liquid flow path section 25 of the second sheet 20 is configured to have a flat surface, but this is not limited thereto, and liquid flow path grooves may be provided in the same manner as the inner peripheral liquid flow path section 15. In this case, the liquid flow path grooves of the first sheet and the liquid flow path grooves of the second sheet are overlapped to form the condensed liquid flow path 3.

14 and 15 is not particularly limited, and may be the same as or different from the width E10 of the inner liquid flow path portion 15 of the first sheet 10. In this embodiment, the width _E10 and the width _E20 are the same.
The influence of misalignment during joining can be reduced when the width _E20 is different from the width _E10 . When the width _E20 is smaller than the width _E10 , the openings of the liquid flow path grooves 15a are not closed by the inner liquid flow path portion 25 in at least a part of the inner liquid flow path portion 15, and the condensed liquid can easily enter and the generated steam can easily exit from these openings, allowing the working fluid to move more smoothly.

Next, the steam flow groove 26 will be described. The steam flow groove 26 is a portion through which the working fluid in the form of vapor and condensed liquid moves, and constitutes a part of the steam flow path 4. Figure 14 shows the shape of the steam flow groove 26 in a plan view, and Figure 15 shows the cross-sectional shape of the steam flow groove 26.

As can be seen from these figures, the steam flow path groove 26 is formed as a groove having a curved portion formed on the inner surface 20a of the main body 21 inside the ring of the annular outer peripheral liquid flow path section 24. More specifically, the steam flow path groove 26 in this embodiment is a groove formed between adjacent inner liquid flow path sections 25 and between the outer peripheral liquid flow path section 24 and the inner liquid flow path section 25. A plurality of steam flow path grooves 26 (six in this embodiment) are arranged in a direction different from the direction in which the steam flow path grooves 26 extend. Therefore, as can be seen from Figure 14, the second sheet 20 has a shape in which convex ridges are formed with the inner liquid flow path sections 25 as convex portions and concave ridges are formed with the steam flow path grooves 26 as concave portions, and these concave and convex portions are repeated.
Here, since the steam flow passage groove 26 is a groove, its cross-sectional shape has a bottom and an opening located on the opposite side facing the bottom.

The steam flow path groove 26 is preferably disposed at a position where it overlaps with the steam flow path groove 16 of the first sheet 10 in the thickness direction when combined with the first sheet 10. In this way, the steam flow path groove 16 and the steam flow path groove 26 can form the steam flow path 4.
14 and 15, the width of the steam flow passage groove 26 indicated by _H20 is not particularly limited, and may be the same as or different from the width _H10 of the steam flow passage groove 16 of the first sheet 10. In this embodiment, the width _H10 and the width _H20 are the same.
When the width _H20 is different from the width _H10 , the influence of misalignment during joining can be reduced. When the width _H20 is made larger than the width _H10 , the openings of the liquid flow path grooves 15a are not closed by the inner liquid flow path portion 25 in at least a part of the inner liquid flow path portion 15 and are open, allowing condensed liquid to easily enter and steam to easily exit, thereby enabling smoother movement of the working fluid.
On the other hand, the depth of the steam flow passage groove 26 indicated by _I20 in FIG. 15 is preferably 10 μm or more and 300 μm or less.

Here, the steam flow channel groove 26 is preferably configured so that the steam flow channel 4 has a flat shape in which the width is greater than the height (size in the thickness direction) when combined with the first sheet 10 to form the steam flow channel 4, as described later. Therefore, the aspect ratio, which is the value obtained by dividing _H20 by _I20, is preferably 4.0 or more, and more preferably 8.0 or more.

In this embodiment, the cross-sectional shape of the steam flow channel groove 26 is semi-elliptical, but it may also be a square, rectangle, trapezoid or other quadrangle, a triangle, a semicircle, a semicircle with a bottom, a semi-ellipse with a bottom, etc.

The steam flow passage connection groove 27 is a groove that, in combination with the steam flow passage connection groove 17 of the first sheet 10, forms a passage that connects the ends of the multiple steam flow passages 4 formed by the steam flow passage groove 26. This allows the movement of the working fluid that occurs in the steam flow passage 4 in the direction in which the inner liquid flow passage section 25 extends to be well balanced. In addition, the working fluid in the steam flow passage 4 is equalized, the steam is transported over a wider area, and many condensate liquid flow passages 3 can be efficiently utilized, making it possible to move the working fluid more smoothly.

As can be seen from Figures 14 and 16, the steam flow passage communication groove 27 in this embodiment is formed between both ends in the direction in which the inner liquid flow passage section 25 extends and both ends in the direction in which the steam flow passage groove 26 extends, and the outer circumferential liquid flow passage section 24. Also, Figure 16 shows a cross section perpendicular to the communication direction of the steam flow passage communication groove 27.

14 and ₁₆ is not particularly limited, and may be the same as or different from the width _J10 of the steam flow passage communication groove 17 of the first sheet 10. When the width _J20 is made larger than the width _J10 , the openings of the liquid flow passage grooves _14a are arranged to form part of the steam flow passage 4 in at least a part of the outer circumferential liquid flow passage portion 14 of the first sheet 10, which makes it easier for condensed liquid to enter and for generated steam to exit, thereby enabling the working fluid to move more smoothly.

The size of the width J ₂₀ is preferably in the range of 100 μm to 1000 μm, and the depth of the steam flow passage communication groove 27 indicated by K ₂₀ in FIG. 14 is preferably in the range of 10 μm to 300 μm.

In this embodiment, the cross-sectional shape of the steam flow passage communication groove 27 is semi-elliptical, but it is not limited to this and may be a square, rectangle, trapezoid or other quadrangle, triangle, semicircle, a semicircle with a bottom, a semi-ellipse with a bottom, etc.

In addition, in this embodiment, the second sheet 20 has a curved portion 28c, which is a portion where the direction in which the outer peripheral liquid flow path portion 24, the inner liquid flow path portion 25, and the steam flow path groove 26 extend changes. That is, as can be seen from Fig. 14, the second sheet 20 has a straight portion 28a where the outer peripheral liquid flow path portion 24, the inner liquid flow path portion 25, and the steam flow path groove 26 extend linearly in the x direction, a straight portion 28b where the outer peripheral liquid flow path portion 24, the inner liquid flow path portion 25, and the steam flow path groove 26 extend linearly in the y direction, and a curved portion 28c that connects the outer peripheral liquid flow path portion 24, the inner liquid flow path portion 25, and the steam flow path groove 26 at the straight portion 28a and the straight portion 28b. Therefore, one end of the curved portion 28c is connected to one straight portion 28a, and the other end is connected to the other straight portion 28b, and the outer peripheral liquid flow path portion 24, the inner liquid flow path portion 25, and the steam flow path groove 26 are curved so that the flow changes direction from the x direction to the y direction and from the y direction to the x direction.

As can be seen from FIG. 14, in the curved portion 28c of this embodiment, the configuration of the outer peripheral liquid flow path portion 24, the inner liquid flow path portion 25, and the steam flow path groove 26 can be considered to be similar to that of the curved portion 18c of the first sheet 10 described above.

Next, a description will be given of the structure when the first sheet 10 and the second sheet 20 are combined to form the vapor chamber 1. This description will provide a further understanding of the arrangement, size, shape, etc. of each component of the first sheet 10 and the second sheet 20.
Fig. 17 shows a cross section of the vapor chamber 1 cut in the thickness direction along the y direction indicated by XV-XV in Fig. 1(a). This figure is a combination of the diagram of the first sheet 10 shown in Fig. 4 and the diagram of the second sheet 20 shown in Fig. 15, showing the cross section of the vapor chamber 1 at this portion.
FIG. 18 shows an enlarged view of the portion indicated by XVI in FIG.
Fig. 19 shows a cross section of the vapor chamber 1 cut in the thickness direction along the x direction indicated by XVII-XVII in Fig. 1(a). This figure shows the cross section of the vapor chamber 1 at this portion by combining the diagram shown in Fig. 5(b) of the first sheet 10 and the diagram shown in Fig. 16 of the second sheet 20.

As can be seen from Figures 1(a), 1(b), and 17 to 19, the first sheet 10 and the second sheet 20 are arranged so as to be overlapped and joined together to form the vapor chamber 1. At this time, the inner surface 10a of the first sheet 10 and the inner surface 20a of the second sheet 20 are arranged so as to face each other, the main body 11 of the first sheet 10 and the main body 21 of the second sheet overlap, and the injection portion 12 of the first sheet 10 and the injection portion 22 of the second sheet 20 overlap.

The laminate of the first sheet 10 and the second sheet 20 allows the components of the main body 11 and the main body 21 to be arranged as shown in Figures 17 to 19. Specifically, they are as follows.

The vapor chamber 1 of this embodiment is particularly effective when it is thin. From this viewpoint, the thickness of the vapor chamber 1 shown by L ₀ in FIG. 1 and FIG. 17 is 1 mm or less, more preferably 0.4 mm or less, and even more preferably 0.2 mm or less. By making it 0.4 mm or less, in electronic devices in which the vapor chamber 1 is installed, the vapor chamber can often be installed inside the electronic device without processing (e.g., forming a groove, etc.) to form a space in which the vapor chamber is to be installed. And according to this embodiment, even such a thin vapor chamber has high strength and is resistant to deformation while maintaining thermal performance.

Meanwhile, the outer peripheral joint portion 13 of the first sheet 10 and the outer peripheral joint portion 23 of the second sheet 20 are arranged so as to overlap, and the two are joined by a joining method such as diffusion bonding or brazing. This forms an enclosed space 2 between the first sheet 10 and the second sheet 20.

The peripheral liquid flow path section 14 of the first sheet 10 and the peripheral liquid flow path section 24 of the second sheet 20 are arranged so as to overlap with each other. As a result, the liquid flow path grooves 14a of the peripheral liquid flow path section 14 and the peripheral liquid flow path section 24 form a condensed liquid flow path 3 through which the condensed liquid, which is the working fluid that has been condensed and liquefied, flows.
Similarly, the inner liquid flow path section 15 which is a convex rib of the first sheet 10 and the inner liquid flow path section 25 which is a convex rib of the second sheet 20 are arranged so as to overlap each other. As a result, the liquid flow path grooves 15a of the inner liquid flow path section 15 and the inner liquid flow path section 25 form a condensate liquid flow path 3 through which the condensate flows.

Here, it is preferable that the cross-sectional shape of the condensate flow path 3 is flattened in accordance with the thinning of the vapor chamber 1. This can increase the capillary force and facilitate smooth movement of the condensate, thereby making it possible to maintain a high level of heat transport capacity. More specifically, it is preferable that the ratio (aspect ratio) of the width of the condensate flow path 3 divided by the height is greater than 1.0 and equal to or less than 4.0.
In this embodiment, the width of the condensate flow path 3 corresponds to the width _F1 of the liquid flow path groove 15a, but is preferably 10 μm to 300 μm. If the width is less than 10 μm, the flow path resistance increases and the transport capacity may decrease. On the other hand, if the width is more than 300 μm, the capillary force decreases and the transport capacity may decrease.
In addition, the height of the condensate flow path 3 is preferably 5 μm or more and 200 μm or less, which corresponds to the depth G of the liquid flow path groove 15a in this embodiment. This allows the capillary force of the condensate flow path required for movement to be fully exerted. Note that this height is preferably less than the thickness (wall thickness) of the first sheet 10 and the second sheet 20 on one side and the other side in the thickness direction (z direction) across the condensate flow path 3. This further prevents the vapor chamber from breaking (rupturing) due to the condensate flow path 3.

The cross-sectional shape of the condensate flow path 3 is semi-elliptical due to the cross-sectional shapes of the liquid flow path grooves 14a and 15a, but is not limited to this and may be a square, rectangle, trapezoid or other quadrangle, triangle, semicircle, semicircular with a bottom, semi-elliptical with a bottom, or a combination of these. It may also be crescent-shaped.

In this embodiment, the liquid flow path grooves 14a and 15a are provided only in the first sheet 10, so the height of the condensate flow path is based on the depth of the liquid flow path grooves 14a and 15a, but this is not limited to the above, and liquid flow path grooves may also be provided in the second sheet 20. In this case, the liquid flow path grooves of the first sheet and the second sheet overlap to form a condensate flow path, and the height of the condensate flow path corresponds to the sum of the depths of both liquid flow path grooves.

In this way, when liquid flow path grooves are provided in the first sheet and the second sheet and then stacked to form a condensate flow path, the condensate flow path can be configured as shown in Figures 20(a) to 20(c).
The example in FIG. 20(a) is an example in which the liquid flow passage grooves of the first sheet and the second sheet have the same width and are disposed at the same positions.
20(b) is an example in which the width of the liquid flow channel in the second sheet is made larger than that of the liquid flow channel in the first sheet, and the positions of the liquid flow channel are the same. In this example, a protrusion is formed in the condensate flow channel as shown by P, which improves the capillary force and increases the force that moves the condensate (the supply force of the condensate).
20(c) is an example in which the liquid flow channel grooves of the first sheet and the second sheet have the same width but are arranged at offset positions. In this example as well, a protrusion is formed in the condensate flow channel as indicated by P, which improves the capillary force and increases the force that moves the condensate (the supply force of the condensate).

As described above, the condensate flow passage 3 is formed with the communication opening 14c and the communication opening 15c. This allows the multiple condensate flow passages 3 to communicate with each other, equalizing the condensate and allowing the condensate to move efficiently. In addition, the communication openings 14c and 15c, which are adjacent to the steam flow passage 4 and connect the steam flow passage 4 and the condensate flow passage 3, allow the condensate generated in the steam flow passage 4 to move smoothly to the condensate flow passage 3, and the steam generated in the condensate flow passage 3 to move smoothly to the steam flow passage 4, allowing the working fluid to move quickly.

In addition, it is preferable that the condensate flow path 3 formed by the peripheral liquid flow path section 14 and the peripheral liquid flow path section 24 is formed in a continuous ring shape along the edge of the sealed space 2. In other words, it is preferable that the condensate flow path 3 formed by the peripheral liquid flow path section 14 and the peripheral liquid flow path section 24 extends in a ring shape around the entire circumference without being interrupted by other components. This reduces factors that hinder the movement of the condensate, allowing the condensate to move smoothly.

As explained above, in this embodiment, the condensate flow path is formed by providing a condensate flow path groove in the sheet, but instead, a means for generating capillary force may be separately disposed here to form the condensate flow path. For this purpose, for example, a so-called wick, such as a mesh material, nonwoven fabric, stranded wire, or sintered metal powder, may be disposed.

The opening of the steam flow passage groove 16 in the first sheet 10 and the opening of the steam flow passage groove 26 in the second sheet 20 overlap each other so as to face each other to form a flow passage, which becomes the steam flow passage 4.
Here, it is preferable that the cross-sectional shape of the vapor flow path 4 is flattened in accordance with the thinning of the vapor chamber 1. This makes it possible to secure the surface area within the flow path even when the vapor chamber 1 is thinned, and makes it possible to maintain a high level of heat transport capacity. More specifically, in the width W _B and height H _B of the vapor flow path 4 shown in FIG. 18, it is preferable that the ratio (aspect ratio) expressed by the value obtained by dividing W _B by H _B is 2.0 or more. From the viewpoint of ensuring even higher heat transport capacity, it is even more preferable that the ratio is 4.0 or more.

As can be seen from FIG. 17, the opening of the steam flow passage communication groove 17 of the first sheet 10 and the opening of the steam flow passage communication groove 27 of the second sheet 20 overlap to face each other to form a flow passage, and the ends of the multiple steam flow passages 4 formed by the steam flow passage grooves 16 and 26 are connected to each other, providing a flow passage for balanced movement of the working fluid.

As described above, the shapes of the first sheet 10 and the second sheet form the condensate flow path 3 and the vapor flow path 4 in the sealed space 2 of the vapor chamber 1. Fig. 18 shows a diagram focusing on the condensate flow path 3 and the vapor flow path formed in the sealed space 2.
18, 21, etc., the vapor chamber 1 has a shape in which a plurality of condensate flow paths 3 are arranged between two vapor flow paths 4. This results in a configuration in which the condensate flow path 3, through which the condensate should mainly flow, and the steam flow path 4, through which the vapor and condensate move, are separated and alternately arranged, which helps smooth movement of the working fluid.

The steam flow path 4 and the condensate flow path 3 allow the working fluid in the form of steam and condensate to move through the steam flow path 4, efficiently transferring and diffusing heat. On the other hand, the condensate flow path 3, which is provided separately from the steam flow path 4, allows the condensate to move efficiently by capillary force, making it possible to suppress the occurrence of dryout.

In addition, in the vapor chamber 1, the condensate flow path 3 and the vapor flow path 4 extend in different directions, and two straight sections 6 are connected by a curved section 7. By forming such a flow path, even if the vapor chamber is placed in an electronic device and there are restrictions on its placement, and it is not possible to form a flow path that is only linear, the curved section 7 can be provided to efficiently transfer heat generated from the heat source to a remote location.

The curved portion 7 is formed by the curved portion 18c of the first sheet 10 and the curved portion 28c of the second sheet 20. Therefore, one end of the curved portion 7 is connected to one straight portion 6, and the other end is connected to the other straight portion 6, and the condensate flow path 3 and the steam flow path 4 are curved so that the flow changes direction from the x direction to the y direction and from the y direction to the x direction.

In this embodiment, the flow passage cross-sectional area (width in this embodiment) of the vapor flow passage 4 is made larger in the curved portion 7 than in the straight portion 6. This makes it possible to reduce the flow resistance in the curved portion 7 where the flow resistance increases due to the curvature of the vapor flow passage 4, and reduces the flow resistance in the vapor chamber as a whole, which makes the movement of the working fluid smoother and increases the heat transport capacity. In this case, the flow passage cross-sectional area of the vapor flow passage 4 in the curved portion 7 may be constant at least within the range of the curved portion 7. This makes it possible to reduce the flow loss of the working fluid due to the expansion and contraction of the flow passage cross-section.
Here, the "cross-sectional area of a flow channel" refers to the cross-sectional area of the flow channel in a plane perpendicular to the direction in which the flow channel extends.

The means, degree, and concept of increasing the flow passage cross-sectional area (width in this embodiment) of the steam flow passage 4 in the curved portion 7 are the same as those described above for the curved portion 18c of the first sheet 10.

As can be seen from FIG. 21, in the curved portion 7 of this embodiment, the condensate flow path 3 and the steam flow path 4 are configured such that the radius of curvature of the outer steam flow path is larger than the radius of curvature of the inner steam flow path in the direction in which these flow paths are arranged. This configuration may be used.

In this embodiment, each of the grooves is curved to draw a concentric arc. However, this is not limited to this, and the center position of the arc may be offset. Furthermore, in the curved portion 7, the longer the length of each flow groove, the larger the radius of curvature.

When multiple curved flow paths are arranged in a vapor chamber, the flow path length is shorter on the inside and longer on the outside, resulting in a large difference in flow resistance between the inside and outside. This difference in flow resistance causes the working fluid movement in the vapor chamber to become unbalanced, which is one of the reasons why sufficient heat transport capacity cannot be achieved. In contrast, by using a configuration with the above-mentioned radius of curvature, it is possible to alleviate the difference in flow resistance between the inside and outside, especially in the vapor flow path 4. This improves the balance of the working fluid movement and also increases the heat transport capacity.

However, this is not limiting, and the radius of curvature of multiple steam flow paths 4 in the curved portion 7 may be the same, following the example of Figure 12.

In addition, in the curved portion 7, the communication openings 14c and 15c (see Figs. 6 and 8(b)) provided in the walls 14b and 15b separating the condensate flow path 3 and the steam flow path 4 can be configured to have a pitch different from that of the straight portion 6. The pitch of the communication openings in the curved portion may be larger or smaller than the pitch of the curved portions in the straight portion. The form to be adopted can be determined by comprehensively judging the form that can reduce the flow resistance, taking into consideration the effects of the overall shape of the vapor chamber, the position of the heat source, etc. Alternatively, the curved portion 7 does not need to have the communication openings 14c and 15c in the walls 14b and 15b separating the condensate flow path 3 and the steam flow path 4.
In a configuration in which the pitch of the communication openings in the curved portion is larger than the pitch of the communication openings in the straight portion, the working fluid flowing through the steam flow path 4 can be prevented from entering the communication openings 14c and 15c at the curved portion 7. In the curved portion 7, the working fluid moving through the steam flow path 4 is subjected to a force that tends to flow directly into the communication openings 14c and 15c due to its flow direction, so that the steam tends to enter the condensate flow path 3 and the flow resistance tends to increase due to the unevenness of the communication openings 14c and 15c. In response to this, by increasing the pitch of the communication openings 14c and 15c that contact the steam flow path 4 at the curved portion 7 or by eliminating the communication openings 14c and 15c that contact the steam flow path 4, it is possible to suppress such an increase in flow resistance, further reducing the difference in flow resistance for each steam flow path 4, improving the balance of the movement of the working fluid, and increasing the heat transport capacity.
On the other hand, in a configuration in which the pitch of the communication openings in the curved portion is smaller than the pitch of the communication openings in the straight portion, the steam flowing through the steam flow passage groove (steam flow passage) has more opportunities to strongly hit the wall surface in the curved portion, so that condensation tends to occur easily. In this case, by making the pitch of the communication openings in the curved portion smaller than the pitch of the communication openings in the straight portion, the number of communication openings can be increased, and the condensate can be smoothly introduced into the liquid flow passage groove (condensate flow passage), making it possible to prevent the steam flow passage from being blocked by the condensate. This can prevent an increase in flow resistance, further reduce the difference in flow resistance between the steam flow passage grooves (steam flow passages), improve the balance of the movement of the working fluid, and increase the heat transport capacity.

In addition, instead of the above-mentioned pitch size, the length of the wall between adjacent communication openings (size along the flow path) in the curved section may be configured to be larger or smaller than the length of the wall in the straight section. In this case, the length of the walls belonging to the curved section does not need to be constant, and may be different for each wall. In this case, the relationship in size between the wall length of the curved section and the wall length of the straight section is determined by the relationship between the average lengths of the walls belonging to each section.

On the other hand, as shown in Figure 1, the inner surfaces 10a and 20a of the injection parts 12 and 22 overlap each other so that they face each other, and the opening on the opposite side to the bottom of the injection groove 22a of the second sheet 20 is blocked by the inner surface 10a of the injection part 12 of the first sheet 10, and an injection flow path 5 is formed that communicates between the outside and the hollow part between the main body 11 and the main body 21 (the condensate flow path 3 and the steam flow path 4).
However, after the working fluid is injected from the injection passage 5 into the sealed space 2, the injection passage 5 is closed, so that in the final form of the vapor chamber 1, the sealed space 2 is not connected to the outside.

A working fluid is sealed in the sealed space 2 of the vapor chamber 1. The type of working fluid is not particularly limited, but working fluids used in ordinary vapor chambers, such as pure water, ethanol, methanol, and acetone, can be used.

A vapor chamber like the one above can be made, for example, as follows:

A sheet made of the material constituting the first sheet 10 and having the outer circumferential shape of the first sheet 10, and a sheet made of the material constituting the second sheet 20 and having the outer circumferential shape of the second sheet 20 are prepared. The liquid flow path groove 14a, liquid flow path groove 15a, steam flow path groove 16, steam flow path groove 26, steam flow path communication groove 17, and steam flow path communication groove 27 described above are formed in these sheets by half etching. Here, half etching refers to removing material by etching partway through the thickness direction without penetrating the thickness direction, thereby forming grooves and depressions.

Next, the etched sheet having the shape of the first sheet 10 and the etched sheet having the shape of the second sheet 20 are overlapped with the inner surface 10a facing the inner surface 20a, and temporarily fixed. The method of temporary fixing is not particularly limited, but examples include resistance welding, ultrasonic welding, and adhesion with an adhesive.
After the temporary fixing, the sheets are bonded permanently by diffusion bonding. Bonding may be used instead of diffusion bonding. However, in the case of a thin vapor chamber as in this embodiment, the flow path is narrow, so if brazing is used with a brazing material, there is a risk that the brazing material will enter the flow path. In addition, since a strong capillary force acts on the flow path as described above, there is a risk that the brazing material will spread over a wide area of the flow path. From this perspective, bonding by welding such as diffusion bonding or ultrasonic bonding, which does not cause such problems, is preferable.

After bonding, a vacuum is drawn through the formed injection flow path 5 to reduce the pressure inside the hollow portion. After that, the working fluid is injected through the injection flow path 5 into the reduced pressure hollow portion, and the working fluid is placed in the hollow portion. The injection flow path 5 is then closed by melting the injection portions 12 and 22 with a laser or by crimping. This creates an enclosed space 2, inside which the working fluid is stably held, forming the vapor chamber 1.

Next, the action of the vapor chamber 1 when it is activated will be described. Figure 22 shows a schematic diagram of the vapor chamber 1 placed inside a portable terminal 40, which is one form of electronic device. Here, the vapor chamber 1 is represented by a dotted line because it is placed inside the housing 41 of the portable terminal 40. Such a portable terminal 40 is configured with a housing 41 that contains various electronic components, and a display unit 42 that is exposed so that images can be seen to the outside through an opening in the housing 41. And as one of these electronic components, an electronic component 30 to be cooled by the vapor chamber 1 is placed inside the housing 41.

The vapor chamber 1 is installed inside the housing of a portable terminal or the like, and is attached to an electronic component 30, which is the object to be cooled, such as a CPU. The electronic component 30 is attached directly to the outer surface 10b or outer surface 20b of the vapor chamber 1, or via a highly thermally conductive adhesive, sheet, tape, or the like.

Fig. 23 is a diagram for explaining the behavior of the working fluid. For ease of explanation, this diagram is taken from the same perspective as Fig. 21, and focuses on the condensate flow path 3 and the steam flow path 4 formed in the sealed space 2.
When the electronic components 30 generate heat, the heat is transferred by thermal conduction within the first sheet 10, and the condensate present in the sealed space 2 at a position close to the electronic components 30 receives the heat. The condensate absorbs the heat and evaporates, thereby cooling the electronic components 30.

The vaporized working fluid becomes vapor and moves through the vapor flow path 4. The vaporized working fluid may move in a vibrating manner within the vapor flow path 4 as shown by the solid straight arrow in Fig. 23, or may move in a direction away from the electronic component 30, which is a heat source, without vibrating, although this is not shown.
At this time, the steam flow path 4 includes the curved portion of the curved portion 7, but since the curved portion 7 has the above-mentioned configuration, even if the flow path lengths are different, the flow resistance is reduced and well-balanced, and the working fluid moves smoothly through the steam flow path 4. This makes it possible to exhibit high heat transport capacity.
During this movement of the working fluid, the working fluid is cooled as heat is absorbed by the first sheet 10 and the second sheet 20. The first sheet 10 and the second sheet 20, which absorb heat from the steam, transfer the heat to the housing of the portable terminal device in contact with their outer surfaces 10b and 20b, and the heat is finally released into the outside air. Then, the working fluid from which heat has been absorbed while moving through the steam flow path 4 condenses and becomes a liquid.

A portion of the condensate generated in the steam flow path 4 moves to the condensate flow path 3 from the communication openings, etc. In this embodiment, the condensate flow path 3 is provided with communication openings 14c and 15c, so the condensate is distributed to multiple condensate flow paths 3 through these communication openings 14c and 15c.

The condensate that enters the condensate flow path 3 moves toward the heat source, electronic component 30, due to the capillary force of the condensate flow path, as shown by the dotted straight arrow in Figure 23. It is then vaporized again by the heat from the heat source, electronic component 30, and the above process is repeated.

As described above, according to the vapor chamber 1, the movement of the working fluid in the vapor flow path and the high capillary force in the condensate flow path make the movement of the working fluid smooth and excellent, thereby increasing the heat transport capacity.
Furthermore, by forming a flow path with a curved portion 7 in the vapor chamber 1, even when the vapor chamber is placed in an electronic device and there are restrictions on its placement, making it impossible to form a flow path that is only in a straight line, the heat generated from the heat source can be efficiently transferred to a remote location.
Furthermore, as described above, the curved section 7 is configured to reduce the flow resistance in the multiple steam flow paths 4 and, if necessary, to reduce the difference in flow resistance, so that the working fluid can be moved in a balanced manner and the heat transport capacity can be increased.

Figures 24 to 31 are diagrams illustrating the vapor chamber 201 in the second embodiment. Figure 24 is an external perspective view of the vapor chamber 201, and Figure 25 is an exploded perspective view of the vapor chamber 201.

24 and 25, the vapor chamber 201 has a first sheet 210, a second sheet 220, and a third sheet 230. The first sheet 210, the second sheet 220, and the third sheet 230 are stacked and joined (diffusion bonding, brazing, etc.) to form a hollow space surrounded by the first sheet 210, the second sheet 220, and the third sheet 230 between the first sheet 210 and the second sheet 220, and the working fluid is sealed in this hollow space to form the sealed space 202.

In this embodiment, the first sheet 210 is a sheet-like member as a whole. The first sheet 210 is composed of flat surfaces on both sides, and has an inner surface 210a, an outer surface 210b opposite the inner surface 210a, and a side surface 210c that spans the inner surface 210a and the outer surface 210b to form a thickness.

The first sheet 210 includes a main body 211 and an injection portion 212. The main body 211 is a sheet-like portion that forms an enclosed space through which the working fluid moves, and in this embodiment, is a rectangle with arcuate corners (so-called R) in a plan view.
Injection portion 212 is a portion where working fluid is injected into the sealed space formed by first sheet 210, second sheet 220, and third sheet 230, and in this embodiment, is a sheet-like shape that is rectangular in plan view and protrudes from the L-shaped body 211 in plan view. In this embodiment, injection portion 212 of first sheet 210 has flat surfaces on both the inner surface 210a side and the outer surface 210b side.

In this embodiment, the second sheet 220 is a sheet-like member as a whole. The second sheet 220 is composed of flat surfaces on both sides, and has an inner surface 220a, an outer surface 220b opposite the inner surface 220a, and a side surface 220c that spans the inner surface 220a and the outer surface 220b to form a thickness.

The second sheet 220 also has a main body 221 and an injection portion 222.

In this embodiment, the third sheet 230 is a sheet sandwiched and overlapped between the inner surface 210a of the first sheet 210 and the inner surface 220a of the second sheet 220, and a structure for moving the working fluid is formed in the main body 231. FIG. 26 shows a plan view of the third sheet 230. FIG. 26(a) shows the surface that is overlapped with the second sheet 220, and FIG. 26(b) shows the surface that is overlapped with the first sheet 210. FIG. 27 shows a cut surface along the line indicated by XXIV-XXIV in FIG. 26(a), and FIG. 28 shows a cut surface along the line indicated by XXV-XXV in FIG. 26(a).

The third sheet 230 includes a main body 231 and an injection portion 232. The main body 231 is a sheet-like portion that forms an enclosed space through which the working fluid moves, and in this embodiment, is L-shaped with a curved portion in a plan view.
Injection portion 232 is a portion where working fluid is injected into the sealed space formed by first sheet 210, second sheet 220, and third sheet 230, and in this embodiment, is a sheet-like shape that is rectangular in plan view and protrudes from main body 231 that is L-shaped in plan view. Injection portion 232 has injection groove 232a formed on the surface side that overlaps first sheet 210. Injection groove 232a can be considered to be similar to injection groove 22a described above.

The main body 231 includes an outer peripheral joint 233, an outer peripheral liquid flow path section 234, an inner liquid flow path section 235, a steam flow path slit 236, and a steam flow path communication groove 237.

The outer periphery bonding portion 233 is a portion formed along the outer periphery of the main body 231. One surface of the outer periphery bonding portion 233 is overlapped and bonded (diffusion bonding, brazing, etc.) to the surface of the first sheet 210, and the other surface is overlapped and bonded (diffusion bonding, brazing, etc.) to the surface of the second sheet 220. As a result, a hollow portion surrounded by the first sheet 210, the second sheet 220, and the third sheet 230 is formed, and the working fluid is sealed in this hollow portion to form the sealed space 202.
The outer peripheral joint 233 can be considered to be similar to the outer peripheral joint 13 described above.

The peripheral liquid flow path section 234 functions as a liquid flow path section and is a part that constitutes a part of the condensed liquid flow path 3, which is a flow path through which the working fluid passes when condensed and liquefied. The peripheral liquid flow path section 234 is formed along the inside of the peripheral joint section 233 of the main body 231, and is provided so as to be annular along the outer periphery of the sealed space 202. A liquid flow path groove 234a is formed on the surface of the peripheral liquid flow path section 234 that faces the second sheet 220. In this embodiment, the liquid flow path groove 234a is provided only on the surface that faces the second sheet 220, but in addition to this, a liquid flow path groove may also be provided on the surface that faces the first sheet 210.
The outer circumferential liquid flow passage portion 234 and the liquid flow passage grooves 234a provided therein can be considered to be similar to the outer circumferential liquid flow passage portion 14 and the liquid flow passage grooves 14a described above.

The inner liquid flow path section 235 also functions as a liquid flow path section, and is a part that constitutes part of the condensed liquid flow path 3 through which the working fluid passes when condensed and liquefied. The inner liquid flow path section 235 is formed to extend with a curved portion inside the ring of the outer peripheral liquid flow path section 234, which is annular, in the main body 231. A plurality of inner liquid flow path sections 235 (five in this embodiment) are arranged in a direction different from the direction of extension, and are disposed between the steam flow path slits 236.

A liquid flow path groove 235a, which is a groove parallel to the extension direction of the inner liquid flow path section 235, is formed on the surface of the inner liquid flow path section 235 facing the second sheet 220. The inner liquid flow path section 235 and the liquid flow path groove 235a can be considered to be similar to the inner liquid flow path section 15 and the liquid flow path groove 15a described above.
In this embodiment, the liquid flow path grooves 235 a are provided only on the surface facing the second sheet 220 , but in addition to this, liquid flow path grooves may also be provided on the surface facing the first sheet 210 .

The steam flow passage slit 236 is a portion where the working fluid in the vapor state and the condensed liquid state moves, and is a slit that constitutes the steam flow passage 4. The steam flow passage slit 236 is constituted by a slit having a curved portion that is formed inside the ring of the annular outer peripheral liquid flow passage section 234 of the main body 231. More specifically, the steam flow passage slit 236 in this embodiment is a slit that is formed between adjacent inner liquid flow passage sections 235 and between the outer peripheral liquid flow passage section 234 and the inner liquid flow passage section 235. Therefore, the steam flow passage slit 236 penetrates the third sheet 230 in the thickness direction (z direction).
A plurality of (six in this embodiment) steam flow passage slits 236 are arranged in a direction different from the extending direction. Therefore, as can be seen from Fig. 27, the third sheet 230 has a shape in which the outer peripheral liquid flow passage portion 234, the inner liquid flow passage portion 235, and the steam flow passage slits 236 are alternately repeated.

Such a steam flow passage slit 236 can be considered to be similar to the steam flow passage 4 formed by combining the steam flow passage groove 16 and the steam flow passage groove 26 described above.

In this embodiment, the cross-sectional shape of the steam flow passage slit 236 is formed by overlapping parts of an ellipse, with the center protruding in the thickness direction, but it is not limited to this and may be other shapes such as a square, rectangle, trapezoid, or other quadrangle, a triangle, a semicircle, a crescent, or a combination of these.

The steam flow passage communication groove 237 is a groove that forms a flow passage that communicates the multiple steam flow passage slits 236. This makes it possible to balance the movement of the working fluid that occurs in the steam flow passage in the extension direction of the inner liquid flow passage section 235.
This also allows the working fluid in the steam flow path to be equalized, the steam to be transported over a wider area, and the condensate flow paths defined by many liquid flow path grooves 234a and 235a to be utilized efficiently.

The steam flow passage communication groove 237 in this embodiment is formed between both ends of the inner liquid flow passage section 235 in the extending direction and both ends of the steam flow passage slit 236 in the extending direction, and the outer circumferential liquid flow passage section 234. The steam flow passage communication groove 237 only needs to be able to communicate with adjacent steam flow passage slits 236, and its shape is not particularly limited, but it can be considered to be similar to a flow passage formed by overlapping the above-mentioned steam flow passage communication groove 17 and steam flow passage communication groove 27.

The third sheet 230 also has a straight portion 238a, a straight portion 238b, and a curved portion 238c so that the condensate flow path 3 and the steam flow path 4 have straight portions and curved portions in the sealed space 202 of the vapor chamber 201. The concept of these straight portions and curved portions is the same as that explained so far.

Such a third sheet 230 can be produced by etching both sides separately, etching both sides simultaneously, pressing, cutting, or the like.

Figures 29 to 31 are diagrams explaining the structure when the first sheet 210, the second sheet 220, and the third sheet 230 are combined to form the vapor chamber 201. Figure 29 shows a cross section taken along the line indicated by XXVI-XXVI in Figure 24, and Figure 30 shows an enlarged view of a portion of Figure 29. Figure 31 shows a cross section taken along the line indicated by XXVIII-XXVIII in Figure 24.

As can be seen from FIG. 24 and FIG. 29 to FIG. 31, the first sheet 210, the second sheet 220, and the third sheet 230 are arranged so as to be overlapped and joined to form the vapor chamber 201. At this time, the inner surface 210a of the first sheet 210 and one surface of the third sheet 230 (the surface on the side on which the liquid flow channel grooves 234a and 235a are not arranged) are arranged to face each other, and the inner surface 220a of the second sheet 220 and the other surface of the third sheet 230 (the surface on which the liquid flow channel grooves 234a and 235a are arranged) are overlapped so as to face each other. Similarly, the injection section 212, the injection section 222, and the injection section 232 of each sheet are also overlapped.

As a result, an enclosed space 202 is formed between the first sheet 210 and the second sheet 220, surrounded by the first sheet 210, the second sheet 220, and the third sheet 230. A condensate flow path 3 and a vapor flow path 4 are formed here. The same concept as that of the vapor chamber 1 described above can be applied to the configuration of the condensate flow path 3 and the vapor flow path 4 within this enclosed space 202.

In the above embodiment, a vapor chamber having a curved portion at the intersection where two straight portions intersect at 90 degrees to form an L-shape has been described. However, the form of the curve is not limited to this, and the above-described curved portion can be applied to other forms as well. For example, the curved portion described above can be applied to each of the intersections where two straight portions extend in a direction that intersects with a T-shape, where two straight portions extend in a direction that intersects with a cross, where two straight portions intersect at an acute angle (an angle smaller than 90 degrees) to form a V-shape, and where two straight portions intersect at an obtuse angle (an angle larger than 90 degrees) to form a V-shape.

REFERENCE SIGNS LIST 1 vapor chamber 2 sealed space 3 condensate flow path 4 steam flow path 10 first sheet 11 main body 12 injection part 13 outer peripheral joint part 14 outer peripheral liquid flow path part 14a liquid flow path groove 14c communication opening 15 inner liquid flow path part 15a liquid flow path groove 15c communication opening 16 steam flow path groove 17 steam flow path communication groove 20 second sheet 21 main body 22 injection part 23 outer peripheral joint part 24 outer peripheral liquid flow path part 25 inner liquid flow path part 26 steam flow path groove 27 steam flow path communication groove 230 third sheet 236 steam flow path slit

Claims (7)

A vapor chamber in which a working fluid is sealed in a sealed space,
The sealed space includes a condensate flow path, which is a flow path through which the working fluid moves in a condensed liquid state.
a steam flow path adjacent to the condensate flow path, through which the working fluid moves in a vapor and condensate state;
a linear portion in which the steam flow passage and the condensate flow passage extend linearly;
a curved portion connected to the straight portion and in which the direction in which the steam flow passage and the condensate flow passage extend changes,
a plurality of walls are arranged adjacent to the steam flow path and along an extension direction of the steam flow path, separating the steam flow path from the condensate flow path ; and a plurality of openings are formed between the walls, communicating the steam flow path with the condensate flow path ;
an arrangement pitch of the openings in the curved portion is different from an arrangement pitch of the openings in the straight portion;
Vapor chamber. The vapor chamber of claim 1, wherein the arrangement pitch of the openings in the curved portion is greater than the arrangement pitch of the openings in the straight portion. The vapor chamber of claim 1, wherein the arrangement pitch of the openings in the curved portion is smaller than the arrangement pitch of the openings in the straight portion. A vapor chamber in which a working fluid is sealed in a sealed space,
The sealed space includes a condensate flow path, which is a flow path through which the working fluid moves in a condensed liquid state.
a steam flow path adjacent to the condensate flow path, through which the working fluid moves in a vapor and condensate state;
a linear portion in which the steam flow passage and the condensate flow passage extend linearly;
a curved portion connected to the straight portion and in which the direction in which the steam flow passage and the condensate flow passage extend changes,
a plurality of walls are arranged adjacent to the steam flow path and along an extension direction of the steam flow path to separate the steam flow path from the condensate flow path, and a plurality of openings are formed between the walls to communicate the steam flow path with the condensate flow path ;
The length of the wall in the curved portion is different from the length of the wall in the straight portion.
Vapor chamber. The vapor chamber of claim 4, wherein the length of the wall in the curved portion is greater than the length of the wall in the straight portion. The vapor chamber of claim 4, wherein the length of the wall at the curved portion is smaller than the length of the wall at the straight portion. A housing and
An electronic component disposed inside the housing;
and a vapor chamber according to any one of claims 1 to 6, which is arranged in direct contact with the electronic component or in contact with another member therebetween.
Electronic devices.

Images