Vapor chamber and electronic device

Abstract

To provide a vapor chamber capable of improving heat transport capacity even when the vapor chamber has a flow path whose direction changes.SOLUTION: A vapor chamber in which a working fluid is enclosed in a sealed space, the sealed space including a condensate liquid flow path that is a flow path through which the working fluid moves in a condensate liquid state and a plurality of vapor flow paths through which the working fluid moves in a vapor state and a condensate liquid state, the vapor flow path including a linear portion in which the vapor flow path extends linearly and a curved portion in which a direction in which the vapor flow path extends changes, the vapor flow path having a larger flow path cross-sectional area in the curved portion than a flow path cross-sectional area in the linear portion, the steam channel is formed such that a width in the curved portion is larger than a width in the linear portion by a range of 10% or more and 100% or less, and the width of the steam channel changes by a tapered inclined surface at a connection portion between the curved portion and the linear portion.SELECTED DRAWING: Figure 21

Description

[Technical Field]

[0001] The present invention relates to a vapor chamber in which a working fluid sealed in a sealed space moves and transfers heat. [Background technology]

[0002] Electronic devices such as personal computers and mobile devices such as mobile phones and tablet computers use electronic components such as CPUs (Central Processing Units). As the amount of heat generated by these electronic components tends to increase with improvements in information processing capabilities, technology to cool them has become important. Heat pipes are a well-known cooling method, in which a working fluid sealed inside the pipe transports and diffuses heat from a heat source to another location by utilizing the phase change of the fluid, thereby cooling the heat source.

[0003] Meanwhile, in recent years, these electronic devices have become significantly thinner, creating a need for cooling means thinner than conventional heat pipes. Vapor chambers have been proposed to address this need. Vapor chambers, sometimes called sheet-type heat pipes, are devices that apply the heat transport concept of heat pipes to flat plate-shaped components. In other words, vapor chambers contain a working fluid sealed between opposing flat plates, and utilize the phase change of this working fluid to transport and diffuse heat from a heat source, thereby cooling the heat source.

[0004] 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 has been necessary to address the restrictions on placement by providing a flow path with a curved portion that changes direction, as described in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-205693 Summary of the Invention [Problem to be solved by the invention]

[0006] However, as described in Patent Document 1, a vapor chamber in which the direction of the flow path of the working fluid changes has the problem that it is difficult to improve the heat transport capacity.

[0007] In view of the above problems, the present invention aims to provide a vapor chamber that can improve heat transport capacity even when it has a flow path that changes direction, and also to provide an electronic device equipped with such a vapor chamber. [Means for solving the problem]

[0008] After extensive research, the inventors discovered that in a vapor chamber having multiple vapor flow paths that change direction, 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, resulting in insufficient heat transport. Furthermore, they discovered that because the multiple vapor flow paths have different lengths, differences in flow resistance occur, preventing the working fluid from moving in a balanced manner. As a result, when the difference in flow resistance becomes large, the heat transport capacity decreases, and it may be impossible to achieve the expected performance. Based on these findings, the inventors completed the present invention. The present invention will now be described.

[0009] One aspect of the present invention is a vapor chamber in which a working fluid is sealed in an enclosed space, and the enclosed space is provided with a condensate flow path, which is a flow path through which the working fluid moves in a condensed liquid state, and multiple vapor flow paths through which the working fluid moves in a vapor and condensed liquid state, and the vapor flow path has a straight section where it extends linearly and a curved section where the direction in which the vapor flow path extends changes, and the cross-sectional area of ​​the steam flow path is larger in the curved section than in the straight section, and the width of the steam flow path is larger in the curved section than in the straight section by 10% or more and 100% or less, and the vapor chamber is formed so that the width of the vapor flow path changes at the connection between the curved section and the straight section due to a tapered inclined surface. [Effects of the Invention]

[0010] According to the present invention, even when the vapor chamber has a flow path whose direction changes, the heat transport capacity can be increased. [Brief explanation of the drawings]

[0011] [Figure 1] 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. [Figure 2] FIG. 2 is a perspective view of the first sheet 10. As shown in FIG. [Figure 3] FIG. 3 is a plan view of the first sheet 10. As shown in FIG. [Figure 4] FIG. 4 is a cross section of the first sheet 10. [Figure 5] 5(a) and 5(b) are other cross-sectional views of the first sheet 10. FIG. [Figure 6] FIG. 6 is a partially enlarged plan view of the outer peripheral liquid flow path section 14. As shown in FIG. [Figure 7] FIG. 7 is a partially enlarged plan view of another example of the outer peripheral liquid flow path section 14. In FIG. [Figure 8] 8(a) is a cross section 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. [Figure 9]9(a) to 9(c) are diagrams illustrating examples of the shape of the curved portion 18c. [Figure 10] FIG. 10 is a diagram illustrating an example in which pillars 16a are provided in the steam flow channel groove 16. [Figure 11] FIG. 11(a) is a plan view focusing on the curved portion 18c, and FIG. 11(b) is a view showing the curved portion 18c in another example. [Figure 12] FIG. 12 is a diagram showing a curved portion 18c in another example. [Figure 13] FIG. 13 is a perspective view of the second sheet 20. As shown in FIG. [Figure 14] FIG. 14 is a plan view of the second sheet 20. As shown in FIG. [Figure 15] FIG. 15 is a cross section of the second sheet 20. [Figure 16] FIG. 16 is another cross section of the second sheet 20. [Figure 17] FIG. 17 is a cross section of the vapor chamber 1. [Figure 18] FIG. 18 is an enlarged view of a part of FIG. [Figure 19] FIG. 19 is another cross-sectional view of the vapor chamber 1. [Figure 20] 20(a) to 20(c) are diagrams illustrating examples of the configuration of the condensate flow path. [Figure 21] FIG. 21 is a diagram illustrating the condensate flow path 3 and the steam flow path 4. [Figure 22] FIG. 22 is a perspective view illustrating the electronic device 40. As shown in FIG. [Figure 23] FIG. 23 is a diagram illustrating the operation of the vapor chamber 1. [Figure 24] FIG. 24 is a perspective view of the vapor chamber 201. [Figure 25] FIG. 25 is an exploded perspective view of the vapor chamber 201. [Figure 26] FIG. 26(a) is a view of the third sheet 230 as seen from one side, and FIG. 26(b) is a view of the third sheet 230 as seen from the other side. [Figure 27] FIG. 27 is a cross section of the third sheet 230. [Figure 28] FIG. 28 shows another cross section of the third sheet 230. [Figure 29] FIG. 29 is a cross section of the vapor chamber 201. [Figure 30] FIG. 30 is an enlarged view of a part of FIG. [Figure 31] FIG. 31 is another cross-sectional view of the vapor chamber 201. DETAILED DESCRIPTION OF THE INVENTION

[0012] 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 changed or exaggerated for clarity. Furthermore, for clarity, illustrations of parts unnecessary for explanation and repeated reference numerals may be omitted.

[0013] Figure 1(a) shows a perspective view of the exterior 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. Here, the xy in-plane direction is the direction along the plate surface of the flat vapor chamber 1, and the z direction is the thickness direction.

[0014] 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 (by diffusion bonding, brazing, etc.) to form a hollow space between the first sheet 10 and the second sheet 20, and a working fluid is sealed in this hollow space to form a sealed space 2 (see, for example, FIG. 17).

[0015] In this embodiment, the first sheet 10 is a sheet-like member overall that is L-shaped in a plan view. Fig. 2 is a perspective view of the first sheet 10 as seen from the inner surface 10a side, and Fig. 3 is a plan view of the first sheet 10 as seen from the inner surface 10a side. Fig. 4 shows a cross section of the first sheet 10 when cut along line IV-IV in Fig. 3. The first sheet 10 has an inner surface 10a, an outer surface 10b opposite the inner surface 10a, and a side surface 10c that spans 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 will be described later, 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, thereby forming a hollow portion, into which the working fluid is sealed to form the sealed space 2.

[0016] 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, which increases the number of situations in which it can be used as a thin vapor chamber.

[0017] 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 with a curved portion in a plan view. Injection section 12 is a section where working fluid is injected into the hollow section formed by first sheet 10 and second sheet 20, and in this embodiment, it 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, injection section 12 of first sheet 10 has flat surfaces on both the inner surface 10a side and the outer surface 10b side.

[0018] A structure for moving the working fluid is formed on the inner surface 10a side of the main body 11. Specifically, the structure includes an outer periphery joining portion 13, an outer periphery liquid flow path portion 14, an inner liquid flow path portion 15, a steam flow path groove 16, and a steam flow path connecting groove 17 on the inner surface 10a side of the main body 11.

[0019] 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 with and joined (by diffusion bonding, brazing, etc.) to the outer peripheral joining portion 23 of the second sheet 20, thereby forming a hollow space between the first sheet 10 and the second sheet 20, and a working fluid is sealed in this hollow space to form the sealed space 2. Figures 3 and 4 show A 10 The width of the outer peripheral joint 13 indicated by ∘ can be set as needed, but is preferably 0.05 mm to 5.0 mm at its narrowest. If this width is smaller 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. Furthermore, if this width is larger 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 and condensate flow paths.

[0020] The peripheral liquid flow path section 14 functions as a liquid flow path section and constitutes part of the condensed liquid flow path 3 (see, for example, FIG. 18), which is a flow path through which the working fluid passes when condensed and liquefied. FIG. 5(a) shows the part indicated by arrow Va in FIG. 4, and FIG. 5(b) shows a cross section taken along Vb-Vb in FIG. 3. Both figures show the cross-sectional shape of the peripheral liquid flow path section 14. FIG. 6 shows an enlarged plan view of the peripheral liquid flow path section 14 as seen from the direction indicated by arrow VI in FIG. 5(a).

[0021] As can be seen from these figures, the peripheral liquid flow path section 14 is formed along the inside of the peripheral joining 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. Furthermore, the peripheral liquid flow path section 14 is 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 a cross section in which the liquid flow path grooves 14a that are recesses and the walls 14b that are protrusions between the liquid flow path grooves 14a are formed in a repeated irregular shape. Here, since the liquid flow path groove 14a is a groove, its cross section has a bottom and an opening on the opposite side facing the bottom.

[0022] By providing a plurality of liquid flow path grooves 14a in this way, the depth and width of each liquid flow path groove 14a can be reduced, and the flow path cross-sectional area of ​​the condensate liquid flow path 3 (see, for example, FIG. 18) can be reduced, making it possible to utilize a large capillary force. On the other hand, by providing a plurality of liquid flow path grooves 14a, the total internal volume of the condensate liquid flow path 3 as a whole can be ensured to be an appropriate size, and the condensate can flow at the required flow rate.

[0023] Furthermore, in the outer peripheral liquid flow path section 14, as can be seen from FIG. 6, adjacent liquid flow path grooves 14a are connected by communication openings 14c provided at intervals in the wall 14b. This promotes equalization of the amount of condensed liquid among the multiple liquid flow path grooves 14a, allowing the condensed liquid to flow efficiently. Furthermore, the communication openings 14c provided in the wall 14b adjacent to the steam flow path groove 16 that forms the steam flow path 4 connect the steam flow path 4 and the condensed liquid flow path 3. Therefore, providing the communication openings 14c allows the condensed liquid generated in the steam flow path 4 to move smoothly to the condensed liquid flow path 3, and also allows the steam generated in the condensed liquid flow path 3 to move smoothly to the steam flow path 4, thereby promoting smooth movement of the working fluid.

[0024] In this embodiment, the communicating openings 14c are arranged so as to face each other at the same position in the direction in which the liquid flow path groove 14a extends, with the liquid flow path groove 14a sandwiched between the communicating openings 14c, as shown in Fig. 6. However, this is not limited to this, and the communicating openings 14c may be arranged at different positions in the direction in which the liquid flow path groove 14a extends, with the liquid flow path groove 14a sandwiched between the communicating openings 14c, as shown in Fig. 7, for example. In other words, in this case, the communicating openings 14c are arranged offset in the direction in which the liquid flow path groove 14a extends. By providing the communication openings 14c in this offset manner, when viewed from the working fluid flowing through the condensate flow path 3, the communication openings 14c do not appear on both sides at the same time, and even when the communication openings 14c appear, there is always a wall 14b on at least one side. Therefore, capillary force can be obtained continuously. From this perspective, forming the communication openings 14c in an offset manner makes it possible to maintain a high capillary force acting on the working fluid, allowing the condensate to flow smoothly.

[0025] The peripheral liquid flow path section 14 having the above-described configuration preferably further has the following configuration. Figures 3, 4, 5(a), and 5(b) show B 10 The width of the outer peripheral liquid flow path portion 14 shown in can be set appropriately based on the size of the entire vapor chamber, etc., but is preferably 0.03 mm or more and 2 mm or less. If this width is smaller than 0.03 mm, there is a risk that the amount of liquid flowing on the outer side will be insufficient. Also, if this width exceeds 2 mm, there is a risk that there will not be enough space for the inner condensate flow path and vapor flow path.

[0026] The width of the liquid flow path groove 14a, indicated by C1 in FIG. 5(a) and FIG. 6, is preferably 10 μm or more and 300 μm or less. Furthermore, the depth of the liquid flow path grooves 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 paths, which is necessary for the condensed liquid to flow, to be fully exerted. Here, the depth D of the liquid flow path grooves is preferably smaller than the remaining sheet thickness obtained by subtracting the depth D of the grooves from the thickness of the first sheet 10. This more reliably prevents 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) of 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 manufacturing, it is preferable that C1 be greater than D, and the aspect ratio is preferably greater than 1.3.

[0027] 5(a) and 6, the width of the wall 14b is preferably 20 μm or more and 300 μm or less. If this width is smaller than 20 μm, the wall 14b is likely to break due to repeated freezing and melting of the working fluid, and if this width is larger 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 path 3.

[0028] The size of the communication opening 14c along the direction in which the liquid flow path groove 14a extends, indicated by C3 in FIG. 6, is preferably 20 μm or more and 180 μm or less. Furthermore, the pitch between adjacent communication openings 14c in the direction in which the liquid flow path grooves 14a extend, indicated by C4 in FIG. 6, is preferably 300 μm or more and 2700 μm or less.

[0029] 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 quadrangular such as square, rectangle, or trapezoid, triangular, semicircular, with a semi-circular bottom, or with a semi-elliptical bottom, etc.

[0030] Furthermore, it is preferable that the liquid flow path groove 14a is formed continuously along the edge of the sealed space. That is, it is preferable that the liquid flow path groove 14a extends annularly around the entire circumference without being interrupted by other components. This reduces factors that hinder the movement of condensed liquid, allowing the condensed liquid to move smoothly.

[0031] In this embodiment, a peripheral liquid flow path section 14 is provided, but it is not necessarily provided, and a configuration may be adopted in which the peripheral liquid flow path section 14 is not provided, taking into consideration the shape of the vapor chamber, the relationship with the device to which the vapor chamber is applied, the usage environment, etc. In this configuration, the peripheral part of the sealed space can be configured as a vapor flow path, and heat can be transported by steam to the peripheral part of the vapor chamber, which may result in higher heat uniformity.

[0032] Returning to Figures 2 to 4, the inner liquid flow path section 15 will 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 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 seen from the direction indicated by arrow VIIIb in Figure 8(a).

[0033] 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 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 that extends with a curved section, and multiple (five in this embodiment) inner liquid flow path sections 15 are arranged at intervals in a direction different from the direction in which they extend, and are arranged between the steam flow path grooves 16. Each inner liquid flow path section 15 is formed with liquid flow path grooves 15a that are grooves parallel to the direction in which the inner liquid flow path section 15 extends, and multiple 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 that are recesses and the walls 15b that are protrusions between the liquid flow path grooves 15a are formed in a repeated irregular pattern. Here, since the liquid flow path groove 15a is a groove, its cross section has a bottom and an opening on the opposite side facing the bottom.

[0034] By providing a plurality of liquid flow path grooves 15a in this way, the depth and width of each liquid flow path groove 15a can be reduced, and the flow path cross-sectional area of ​​the condensate liquid flow path 3 (see, for example, FIG. 18) can be reduced, making it possible to utilize a large capillary force. On the other hand, by providing a plurality of liquid flow path grooves 15a, the total internal volume of the condensate liquid flow path 3 as a whole can be ensured to be an appropriate size, and the condensate can flow at the required flow rate.

[0035] Furthermore, as can be seen from FIG. 8(b), in the inner liquid flow path section 15, similar to the example of the outer peripheral liquid flow path section 14 shown in FIG. 6, adjacent liquid flow path grooves 15a are connected to each other by communication openings 15c provided at intervals in the wall 15b. This promotes equalization of the amount of condensate among the multiple liquid flow path grooves 15a, allowing the condensate to flow efficiently. Furthermore, the communication openings 15c provided in the wall 15b adjacent to the steam flow path groove 16 that forms the steam flow path 4 connect the steam flow path 4 to the condensate flow path 3. Therefore, as will be described later, by providing the communication openings 15c, the condensate generated in the steam flow path 4 can be smoothly transferred to the condensate flow path 3, and the steam generated in the condensate flow path can be smoothly transferred to the steam flow path 4, thereby promoting smooth movement of the working fluid.

[0036] In the inner liquid flow path section 15, similar to the example of FIG. 7, the communication openings 15c may be arranged at different positions in the direction in which the liquid flow path groove 15a extends, sandwiching the groove. By providing the communication openings 15c in this offset manner, when viewed from the working fluid flowing through the condensate flow path 3, the communication openings 15c do not appear on both sides at the same time, and even when the communication openings 15c appear, there is always a wall 15b on at least one side. Therefore, capillary force can be obtained continuously. From this perspective, forming the communication openings 15c in an offset manner can maintain a high capillary force acting on the working fluid, allowing for smoother movement of the working fluid.

[0037] The inner liquid flow path section 15 having the above-described configuration preferably further has the following configuration. Figures 3, 4, and 8(a) show E 10 The width of the inner liquid flow path section 15 indicated by is preferably 100 μm or more and 2000 μm or less. The pitch between the plurality of 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 for 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.

[0038] The width of the liquid flow path groove 15a, indicated by F1 in FIGS. 8(a) and 8(b), is preferably 10 μm or more and 300 μm or less. Furthermore, 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, which is necessary for the movement of 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 more reliably prevents 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) of 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 be greater than G, and the aspect ratio is preferably greater than 1.3.

[0039] 8(a) and 8(b), the width of the wall 15b, indicated by F2, is preferably 20 μm or more and 300 μm or less. If the width is less than 20 μm, the wall 15b is likely to break due to repeated freezing and melting of the working fluid. If the width is greater than 300 μm, the width of the communication opening 15c becomes too large, which may hinder smooth communication between the condensate flow paths 3.

[0040] The size of the communication opening 15c along the direction in which the liquid flow path 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 the liquid flow path groove 15a extends, indicated by F4 in FIG. 8(b), is preferably 300 μm or more and 2700 μm or less.

[0041] In addition, in this embodiment, the cross-sectional shape of the liquid flow path groove 15a is semi-elliptical, but is not limited to this and may be quadrangular such as square, rectangle, or trapezoid, triangular, semicircular, or may have a semi-circular bottom or a semi-elliptical bottom.

[0042] Next, the steam flow channel groove 16 will be described. The steam flow channel groove 16 is a portion through which the working fluid in the vapor state and condensed liquid state moves, and constitutes a part of the steam flow channel 4. Fig. 3 shows the shape of the steam flow channel groove 16 in a plan view, and Fig. 4 shows the cross-sectional shape of the steam flow channel groove 16.

[0043] As can be seen from these figures, the steam flow path grooves 16 are configured as grooves formed on the inner surface 10a of the main body 11, inside the ring of the annular outer peripheral liquid flow path section 14. More specifically, the steam flow path grooves 16 in this embodiment are grooves 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 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 depressions are repeated, with the inner liquid flow path sections 15 as protrusions and the steam flow path grooves 16 as recesses. Here, since the steam flow channel groove 16 is a groove, its cross-sectional shape has a bottom and an opening located on the opposite side facing the bottom.

[0044] The steam flow path groove 16 may be configured so that, when combined with the steam flow path groove 26 of the second sheet 20 to form the steam flow path 4, the working fluid moves through the steam flow path 4. Therefore, it is preferable that the steam flow path groove 16 further has the following configuration. Figures 3 and 4 show H 10 The width of the vapor flow channel groove 16 indicated by is formed to be at least larger than the widths C1 and F1 of the liquid flow channel grooves 14a and 15a, and is preferably 100 μm or more and 2000 μm or less. On the other hand, in Figure 4, 10 The depth of the vapor flow channel groove 16 indicated by is formed to be at least greater than the depth D and depth G of the liquid flow channel groove 14a and the liquid flow channel groove 15a, and is preferably 10 μm or more and 300 μm or less. This allows for 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.

[0045] Here, the steam flow channel groove 16 is preferably configured so that when combined with the second sheet 20 to form the steam flow channel 4, as will be described later, the steam flow channel 4 has a flat shape in which the width is greater than the height (size in the thickness direction). 10 I 10 The aspect ratio, which is the value obtained by dividing the ratio by 1, is preferably 4.0 or more, and more preferably 8.0 or more.

[0046] 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 quadrangular such as square, rectangle, or trapezoid, triangular, semicircular, or may have a circular bottom or a semi-elliptical bottom.

[0047] The steam flow path communication grooves 17 are grooves that connect the multiple steam flow path grooves 16 together and, in combination with the steam flow path communication grooves 27 of the second sheet 20, form flow paths that connect the multiple steam flow paths 4 formed by the steam flow path grooves 16 at their ends. This allows for smooth movement of the working fluid generated in the steam flow paths 4 in the direction in which the inner liquid flow path section 15 extends. This also allows the working fluid in the steam flow path 4 to be equalized, the steam to be transported over a wider area, and the condensate flow path 3, which is made up of many liquid flow path grooves 14a and 15a, can be used efficiently.

[0048] 2 and 3, the steam flow path communication grooves 17 in this embodiment are formed between both ends in the direction in which the inner liquid flow path section 15 extends and both ends in the direction in which the steam flow path grooves 16 extend, and the outer peripheral liquid flow path section 14. FIG. 5(b) shows a cross section perpendicular to the communication direction of the steam flow path communication grooves 17. Note that the boundary between the steam flow path communication grooves 17 and the steam flow path grooves 16 is not necessarily formed by a boundary due to shape, and therefore, for ease of understanding, the boundary is shown by a dotted line in FIGS. 2 and 3.

[0049] The steam flow path communication groove 17 may have any shape as long as it can communicate with adjacent steam flow path grooves 16, and may have the following configuration, for example. In Fig. 3 and Fig. 5(b), 10 The width of the steam flow path communicating groove 17 indicated by is preferably 100 μm or more and 1000 μm or less. Also, in Fig. 5(b), K 10 The depth of the steam flow path communicating grooves 17 indicated by is preferably 10 μm or more and 300 μm or less, and is preferably the same as the depth I10 of the steam flow path grooves 16. This makes it easier to manufacture the first sheet 10.

[0050] In this embodiment, the cross-sectional shape of the steam flow path communication groove 17 is semi-elliptical, but is not limited to this and may be quadrangular such as square, rectangle, or trapezoid, triangular, semicircular, or with a semi-circular bottom or a semi-elliptical bottom, etc.

[0051] In this embodiment, the first sheet 10 also has curved portions 18c, which are locations where the extension directions of the liquid flow path grooves 14a (outer peripheral liquid flow path section 14), the liquid flow path grooves 15a (inner liquid flow path section 15), and the steam flow path grooves 16 change. That is, the first sheet 10 has straight portions 18a where the liquid flow path grooves 14a (outer peripheral liquid flow path section 14), the liquid flow path grooves 15a (inner liquid flow path section 15), and the steam flow path grooves 16 extend linearly in the x direction, straight portions 18b where the liquid flow path grooves 14a (outer peripheral liquid flow path section 14), the liquid flow path grooves 15a (inner liquid flow path section 15), and the steam flow path grooves 16 extend linearly in the y direction, and curved portions 18c that connect the liquid flow path grooves 14a (outer peripheral liquid flow path section 14), the liquid flow path grooves 15a (inner liquid flow path section 15), and the steam flow path grooves 16 at the straight portions 18a and 18b. Therefore, one end of the curved portion 18c is connected to one of the straight portions 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 vapor 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 section and the curved section can be defined as the point where the flow direction begins to change in each groove. The same can be considered below. Figure 11(a) shows an enlarged view of the curved section 18c in Figure 3.

[0052] As can be clearly seen from Figures 3 and 11(a), in this embodiment, the width of the vapor flow channel groove 16 is larger in the curved portion 18c than in the straight portion 18a and the straight portion 18b. This reduces the flow resistance in the curved portion 18c, where the flow resistance increases due to the curvature of the flow channel, and reduces the flow resistance throughout the vapor chamber, resulting in smoother movement of the working fluid and improved heat transport capacity. In this case, the width may be constant within the curved portion 18c. This allows the flow resistance of the working fluid to be kept low.

[0053] There are no particular limitations on the means for making the width of the steam flow path grooves 16 in the curved portions 18c larger than the width of the steam flow path grooves 16 in the straight portions 18a and 18b. In this embodiment, this is achieved by making the widths of the outer peripheral liquid flow path section 14 and the inner liquid flow path section 15 in the portions belonging to the curved portions 18c smaller than the widths of the outer peripheral liquid flow path section 14 and the inner liquid flow path section 15 in the portions belonging to the straight portions 18a and 18b. In this case, the widths of the liquid flow path grooves 14a of the outer peripheral liquid flow path section 14 and the liquid flow path grooves 15a of the inner liquid flow path section 15 in these portions may be made smaller, or the number of the liquid flow path grooves 14a and the liquid flow path grooves 15a may be reduced.

[0054] Alternatively, 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 is made 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. Specific examples are shown in Figs. 9(a) to 9(c) for illustrative purposes.

[0055] 9(a) to 9(c) are explanatory views focusing on one steam flow path groove 16. The same can be applied to the other steam flow path grooves 16. The meanings of the symbols shown in FIGS. 9(a) to 9(c) are as follows: The steam flow channel groove 16 is formed on the inner wall of the curved portion 18c. in is the radius of curvature r in and the center is an arc of O1. The steam flow groove 16 is formed on the outer wall of the curved portion 18c. out is the radius of curvature r out and has an arc shape with its center at O1, O2, or O3 depending on the configuration, as will be explained later. The width of the steam flow channel groove 16 is α at the straight portion 18a and the straight portion 18b, but the width of the steam flow channel groove 16 is increased to β at the curved portion 18c (α<β). The curve shown by the dotted line is a virtual line when the width of the steam flow channel groove 16 is maintained at α even at the curved portion 18c, and the radius of curvature in this case is r c and the center is an arc of O1. Here, the radius of curvature can be determined by considering a circle that passes through three points: two points where the orientation of the walls (inner wall, outer wall) in the curved portion begins to change, and one point in the middle of these two points. Furthermore, when the curve is considered to be a portion of a circle or an ellipse, as shown in Figures 9 and 11, the circle is considered to be the "inside" of the curved portion, the center side of the ellipse (i.e., the O1, O2, and O3 side) is considered to be the "inside" of the curved portion, and the side opposite the circle and the center side of the ellipse is considered to be the "outside" of the curve. Furthermore, the shape of the curve is not limited to a shape resembling a portion of a perfect circle, but may also be a shape resembling a portion of an ellipse, or a shape in which some of the steam flow grooves arranged in the curved portion are straight. The same can be applied to shapes related to curved portions below.

[0056] In the example of FIG. 9(a), the outer wall w of the steam flow channel groove 16 is out Radius of curvature r out is the radius of curvature r c is greater than (r out >r c) and its center is O1.

[0057] In the example of FIG. 9(b), the outer wall w of the steam flow channel groove 16 is out Radius of curvature r out is the radius of curvature r c Same as (r out =r c ), but its center is at O2 which is shifted toward the steam flow channel groove 16 side from O1.

[0058] In the example of FIG. 9(c), the outer wall w of the steam flow channel groove 16 is out Radius of curvature r out is the radius of curvature r in and radius of curvature r c is smaller than (r out <r in <r c ), the center of which is at O3 which is shifted toward the steam flow groove 16 side from O1.

[0059] In the examples of Figures 9(a) and 9(b), the outer wall w out In the figure, the linear portion and the arc portion are connected by a single bending portion, but this single bending portion may be replaced by multiple small bending portions or a curved portion, so that the connection changes direction gradually and smoothly.

[0060] 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 flow resistance, but it is preferable that the width be 10% to 100% larger than that of the straight portions 18a and 18b. If the width is less than 10%, there is a risk that flow resistance will not be sufficiently reduced. On the other hand, if the width of the steam flow path groove in the curved portion 18c is increased by more than 100% compared to that of the straight portions 18a and 18b, there is a risk that the flow resistance in the straight portions will increase.

[0061] While the above configurations have been described with a focus on the width of the steam flow channel grooves, the depth of the steam flow channel grooves 16 at the curved portions 18c may alternatively or additionally be made deeper than the straight portions 18a and 18b. A configuration that changes the depth direction suppresses expansion in the planar direction (x and y directions), thereby increasing the area where the condensate flow channel is located, improving heat transport capacity, or allowing for a wider peripheral joint, improving pressure resistance reliability. In this case, the depth may be constant within the curved portions 18c. This reduces the flow resistance of the working fluid. The difference in depth is not particularly limited as long as it is possible to reduce flow resistance, but it is desirable that the steam flow channel grooves be 10% or more deeper in the curved sections than in the straight sections. If it is less than 10%, there is a risk that flow resistance will not be reduced sufficiently.

[0062] 10, the vapor flow channel groove 16 in the curved portion 18c may have multiple pillars 16a arranged upright from the bottom at the center of its width. These pillars support the first sheet 10 and the second sheet 20 of the vapor chamber 1. Therefore, increasing the width of the vapor flow channel groove in the curved portion 18c can prevent a decrease in strength due to the increased width of the vapor flow channel. Specifically, this can prevent the vapor flow channel from collapsing due to insufficient strength when joining or decompressing the first sheet 10 and the second sheet 20 to form the vapor chamber 1, or 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 grooves 16. However, this is not limiting, and pillars 16a may be provided for any other steam flow path grooves 16 as needed, or pillars 16a may be provided for all steam flow path grooves 16.

[0063] In this embodiment, as shown in Fig. 11(a), the width of the steam flow channel groove 16 is formed to change stepwise at the connection portion between the curved portion and the straight portion. In contrast, in the example shown in Fig. 11(b), the width of the steam flow channel groove 16 is formed to change gradually at the connection portion between the curved portion and the straight portion due to a tapered inclined surface. This makes it possible to prevent the generation of vortices when the working fluid passes through the connection portion, and further makes it possible to keep the flow resistance low.

[0064] Furthermore, in the above embodiment, the widths of the plurality of steam flow path grooves 16 are the same in the curved portion 18c, but this is not limiting and the widths of the steam flow path grooves may be changed. In this case, for example, the groove width of the steam flow path groove with a large radius of curvature may be made larger than the groove width of the steam flow path groove with a small radius of curvature, thereby reducing the flow resistance of the steam flow path with a large radius of curvature, which requires a long steam travel distance. Furthermore, the groove width of the steam flow path grooves having a small radius of curvature may be made larger than the groove width of the steam flow path grooves 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 widths of the steam flow channel grooves with larger radii and the steam flow channel grooves with smaller radii may be made larger for the steam flow channel arranged 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 channel grooves, improve the balance of the movement of the working fluid, and increase the heat transport capacity.

[0065] 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 steam flow path grooves 16 are configured so that 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 the direction in which these flow path grooves are arranged.

[0066] In this embodiment, the plurality of grooves are curved to form concentric arcs. However, the center positions of the arcs may be offset, and the curved portion 18c is configured such that the longer the length of each groove, the larger the radius of the groove.

[0067] When multiple curved flow paths are arranged in a vapor chamber, the flow path lengths are shorter toward the inside and longer toward the outside, resulting in a large difference in flow resistance between the inside and outside. This difference in flow resistance can lead to an imbalance in the movement of the working fluid in the vapor chamber, which can be a factor in preventing sufficient heat transport capacity. In contrast, by using a configuration with the above-described radius of curvature, it is possible to mitigate the difference in flow resistance between the inside and outside, particularly in the vapor flow path grooves 16. This improves the balance of the movement of the working fluid and further increases heat transport capacity.

[0068] However, the present invention is not limited to this, and as shown in FIG. 12, the radius of curvature of the plurality of steam flow path grooves 16 may be the same in the curved portion 18c.

[0069] Furthermore, in the curved portion 18c, the communication openings 14c and 15c (see FIGS. 6 and 8(b)) provided in the walls 14b and 15b separating the liquid flow path grooves 14a and 15a from the vapor flow path groove 16 can be configured to have a different pitch from that of the other portions (straight portions 18a and 18b). The pitch of the communication openings in the curved portion may be larger or smaller than the pitch of the curved openings in the straight portions. Which configuration is adopted can be determined by comprehensively determining the configuration that can reduce flow resistance, taking into account the effects of the overall shape of the vapor chamber, the position of the heat source, and the like. 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 path grooves 14a and 15c from the vapor flow path groove 16. In a configuration in which the pitch of the communication openings in the curved portions is greater than the pitch of the communication openings in the straight portions, the curved portions 18c can prevent the working fluid flowing through the steam flow channel grooves 16 (steam flow channel 4) from entering the communication openings 14c and 15c. In the curved portions 18c, a force acts on the working fluid moving through the steam flow channel grooves 16 (steam flow channel 4) to flow directly into the communication openings 14c and 15c due to its flow direction. This can lead to steam entering the condensate flow channel 3 or to increased flow resistance 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 channel grooves 16 in the curved portions 18c or by eliminating the communication openings 14c and 15c that contact the steam flow channel grooves 16, this increase in flow resistance can be prevented. This can further reduce the difference in flow resistance between the steam flow channel grooves 16 (steam flow channels 4), improve the balance of the working fluid movement, and potentially increase heat transport capacity. On the other hand, when the pitch of the communication openings in the curved sections is smaller than that of the communication openings in the straight sections, the steam flowing through the steam flow grooves (steam flow paths) tends to condense more easily because the steam hits the wall surfaces more strongly in the curved sections. In this case, by making the pitch of the communication openings in the curved sections smaller than that of the communication openings in the straight sections, the number of communication openings can be increased, allowing condensate to smoothly flow into the liquid flow grooves (condensate flow paths) and preventing the steam flow paths from being blocked by condensate. This can prevent an increase in flow resistance, further reduce the difference in flow resistance between the steam flow grooves (steam flow paths), improve the balance of working fluid movement, and potentially increase heat transport capacity.

[0070] Next, the second sheet 20 will be described. In this embodiment, the second sheet 20 is also a sheet-like member overall, and is curved in an L-shape in plan view. Fig. 13 shows a perspective view of the second sheet 20 as seen from the inner surface 20a side, and Fig. 14 shows a plan view of the second sheet 20 as seen from the inner surface 20a side. Fig. 15 shows a cross section of the second sheet 20 when cut along XIII-XIII in Fig. 14. Fig. 16 shows a cross section 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 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 will be described later, the inner surface 20a of this second sheet 20 and the inner surface 10a of the first sheet 10 are overlapped and joined so as to face each other, thereby forming a hollow portion, into which the working fluid is sealed to form the sealed space 2.

[0071] 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, which increases the number of situations in which it can be used as a thin vapor chamber.

[0072] 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 with a curved portion in a plan view. Injection portion 22 is a portion where working fluid is injected into the hollow portion formed by first sheet 10 and 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, injection portion 22 of second sheet 20 has injection groove 22a formed on the inner surface 20a side, which communicates from side surface 20c of second sheet 20 to the inside of main body 21 (the hollow portion, the portion that will become sealed space 2).

[0073] A structure for moving the working fluid is formed on the inner surface 20a side of the main body 21. Specifically, the inner surface 20a side of the main body 21 is provided with an outer periphery joining portion 23, an outer periphery liquid flow path portion 24, an inner liquid flow path portion 25, a steam flow path groove 26, and a steam flow path connecting groove 27.

[0074] 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 is overlapped with and joined (by diffusion bonding, brazing, etc.) to the outer peripheral joining portion 13 of the first sheet 10, thereby forming a hollow space between the first sheet 10 and the second sheet 20, and a working fluid is sealed in this hollow space to form the sealed space 2. Figures 14, 15, and 16 show A 20 The width of the outer peripheral joint 23 indicated by is the width A of the outer peripheral joint 13 of the main body 11. 10 is preferably the same as

[0075] The outer circumferential liquid flow path section 24 functions as a liquid flow path section, and is a portion that constitutes a part of the condensed liquid flow path 3 (see, for example, FIG. 18), which is a flow path through which the working fluid passes when condensed and liquefied.

[0076] The peripheral liquid flow path section 24 is formed along the inside of the peripheral joining section 23 on the inner surface 20a of the main body 21, and is formed in a ring shape along the outer periphery of the sealed space 2. In this embodiment, the peripheral liquid flow path section 24 of the second sheet 20 is a flat surface and is flush with the peripheral joining section 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 multiple liquid flow path grooves 14a of the first sheet 10 described above, thereby forming the condensate flow paths 3. Detailed aspects of the combination of the first sheet 10 and the second sheet 20 will be described later. In this way, since the outer peripheral joining portion 23 and the outer peripheral liquid flow path portion 24 are flush with each other in the second sheet 20, there is no structural boundary line that distinguishes them. However, for ease of understanding, the boundary between them is indicated by a dotted line in Figures 13 and 14.

[0077] The peripheral liquid flow path section 24 preferably has the following configuration. The width B of the outer peripheral liquid flow path portion 24 shown in FIGS. 14, 15, and 16 20 is not particularly limited, and the width B of the outer peripheral liquid flow path portion 14 of the first sheet 10 10 In this embodiment, the width B 10 and width B 20 is the same as. Width B 20 Width B 10If the diameter is made smaller, the opening of the liquid flow path groove 14a is not blocked by the peripheral liquid flow path section 24 in at least a part of the peripheral liquid flow path section 14 and is open, allowing condensed liquid to easily enter and steam to easily exit, thereby enabling smoother movement of the working fluid.

[0078] In this embodiment, the peripheral liquid flow path section 24 of the second sheet 20 is configured to have a flat surface, but this is not limiting, and liquid flow path grooves may be provided similarly to the peripheral liquid flow path section 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 condensate flow path 3.

[0079] Furthermore, in this embodiment, as explained in connection with the first sheet, the peripheral liquid flow path section 24 does not necessarily have to be provided, and the peripheral liquid flow path section 24 may not be provided.

[0080] Next, a description will be given of the inner liquid flow path section 25. The inner liquid flow path section 25 is also a liquid flow path section, and is one of the parts that constitute the condensed liquid flow path 3.

[0081] 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 section 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, thereby forming the condensate liquid flow paths 3. When grooves for forming the condensate flow paths 3 are not 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 (tear) on the second sheet side of the vapor chamber.

[0082] 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, similar to 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 condensate flow paths 3.

[0083] The width E20 of the inner liquid flow path section 25 shown in Figures 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 section 15 of the first sheet 10. 10 and width E 20 is the same as. Width E 20 and width E 10 If the width E is different from the width E, the influence of misalignment during joining can be reduced. 20 Width E 10 If it is made smaller, in at least a part of the inner liquid flow path section 15, the opening of the liquid flow path groove 15a is not blocked by the inner liquid flow path section 25 but is open, making it easier for condensed liquid to enter and for generated steam to escape, thereby allowing the working fluid to move more smoothly.

[0084] Next, the steam flow path groove 26 will be described. The steam flow path groove 26 is a portion through which the working fluid in the vapor state and condensed liquid state moves, and constitutes a part of the steam flow path 4. Fig. 14 shows the shape of the steam flow path groove 26 in a plan view, and Fig. 15 shows the cross-sectional shape of the steam flow path groove 26.

[0085] As can be seen from these figures, the steam flow path grooves 26 are configured as grooves with curved portions 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 grooves 26 in this embodiment are grooves 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, with these concave and convex portions being repeated. Here, since the steam flow channel groove 26 is a groove, its cross-sectional shape has a bottom and an opening located on the opposite side facing the bottom.

[0086] The steam flow path grooves 26 are preferably arranged at positions that overlap the steam flow path grooves 16 of the first sheet 10 in the thickness direction when combined with the first sheet 10. This allows the steam flow path grooves 16 and 26 to form the steam flow paths 4. Figures 14 and 15 show H 20 The width of the steam flow channel groove 26 shown by is not particularly limited, and the width H of the steam flow channel groove 16 of the first sheet 10 10 In this embodiment, the width H 10 and width H 20 is the same as. Width H 20 and width H 10 If the width H is different from the width H, the influence of misalignment during joining can be reduced. 20 Width H 10 If it is made larger, in at least a part of the inner liquid flow path section 15, the opening of the liquid flow path groove 15a is not blocked by the inner liquid flow path section 25 but is open, making it easier for condensed liquid to enter and steam to exit, thereby allowing for smoother movement of the working fluid. On the other hand, in Fig. 15, 20 The depth of the vapor flow channel groove 26 indicated by is preferably 10 μm or more and 300 μm or less.

[0087] Here, the steam flow channel groove 26 is preferably configured so that when combined with the first sheet 10 to form the steam flow channel 4, the width of the steam flow channel 4 is greater than the height (size in the thickness direction). 20 I 20 The aspect ratio, which is the value obtained by dividing the ratio by 1, is preferably 4.0 or more, and more preferably 8.0 or more.

[0088] In this embodiment, the cross-sectional shape of the steam flow channel groove 26 is semi-elliptical, but it may be quadrangular such as square, rectangle, or trapezoid, triangular, semicircular, or with a semicircular bottom or a semi-elliptical bottom.

[0089] The steam flow path communication grooves 27 are grooves that, in combination with the steam flow path communication grooves 17 of the first sheet 10, form flow paths that communicate the ends of the multiple steam flow paths 4 formed by the steam flow path grooves 26. This allows for a well-balanced movement of the working fluid that occurs in the steam flow paths 4 in the direction in which the inner liquid flow path section 25 extends. Furthermore, the working fluid in the steam flow paths 4 is equalized, steam is transported over a wider area, and many condensate flow paths 3 can be used efficiently, making it possible to more smoothly move the working fluid.

[0090] 14 and 16, the steam flow path communication grooves 27 of this embodiment are formed between both ends in the direction in which the inner liquid flow path section 25 extends and both ends in the direction in which the steam flow path grooves 26 extend, and the outer circumferential liquid flow path section 24. Also, Fig. 16 shows a cross section perpendicular to the communication direction of the steam flow path communication grooves 27.

[0091] Figures 14 and 16 show J 20 The width of the steam flow path communicating groove 27 shown by is not particularly limited, and the width J of the steam flow path communicating groove 17 of the first sheet 10 10 may be the same as the width J 10 It may be different from the width J 20 Width J 10When the distance is larger than 1 / 2 mm, the openings of the liquid flow path grooves 14a are positioned to form part of the steam flow path 4 in at least a part of the outer peripheral liquid flow path portion 14 of the first sheet 10, making it easier for condensed liquid to enter and for generated steam to exit, thereby allowing the working fluid to move more smoothly.

[0092] Width J 20 The size of is preferably in the range of 100 μm or more and 1000 μm or less, and K 20 The depth of the vapor flow path communicating groove 27 indicated by is preferably 10 μm or more and 300 μm or less.

[0093] In this embodiment, the cross-sectional shape of the steam flow path communication groove 27 is semi-elliptical, but is not limited to this and may be square, rectangular, trapezoidal or other quadrilateral, triangular, semicircular, or with a semi-circular bottom or a semi-elliptical bottom.

[0094] In this embodiment, the second sheet 20 also has curved portions 28c, which are portions where the extension directions of the outer peripheral liquid channel section 24, the inner liquid channel section 25, and the steam channel grooves 26 change. That is, as can be seen from Fig. 14, the second sheet 20 has straight portions 28a where the outer peripheral liquid channel section 24, the inner liquid channel section 25, and the steam channel grooves 26 extend linearly in the x direction, straight portions 28b where the outer peripheral liquid channel section 24, the inner liquid channel section 25, and the steam channel grooves 26 extend linearly in the y direction, and curved portions 28c that connect the outer peripheral liquid channel section 24, the inner liquid channel section 25, and the steam channel grooves 26 at the straight portions 28a and 28b. Therefore, one end of the curved portion 28c is connected to one of the straight portions 28a and the other end is connected to the other straight portion 28b, and the outer circumferential 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.

[0095] As can be seen from Figure 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.

[0096] Next, we will explain the structure when the first sheet 10 and the second sheet 20 are combined to form the vapor chamber 1. This explanation will help you better understand the arrangement, size, shape, etc. of each component of the first sheet 10 and the second sheet 20. Figure 17 shows a cross section of the vapor chamber 1 cut in the thickness direction along the y direction indicated by XV-XV in Figure 1(a). This figure combines the diagram of the first sheet 10 shown in Figure 4 and the diagram of the second sheet 20 shown in Figure 15 to show the cross section of the vapor chamber 1 at this location. FIG. 18 shows an enlarged view of the portion indicated by XVI in FIG. Figure 19 shows a cross section of the vapor chamber 1 cut in the thickness direction along the x direction indicated by XVII-XVII in Figure 1(a). This figure combines the diagram of the first sheet 10 shown in Figure 5(b) and the diagram of the second sheet 20 shown in Figure 16 to show the cross section of the vapor chamber 1 at this location.

[0097] 1(a), 1(b), and 17 to 19, the first sheet 10 and the second sheet 20 are arranged so as to overlap and are 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.

[0098] By laminating the first sheet 10 and the second sheet 20 in this manner, the components provided in the main body 11 and the main body 21 are arranged as shown in Figures 17 to 19. Specifically, they are as follows.

[0099] The vapor chamber 1 of this embodiment is particularly effective when it is thin. From this perspective, the thickness of the vapor chamber 1, indicated by L0 in FIGS. 1 and 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, it is often possible to install the vapor chamber inside the electronic device in which the vapor chamber 1 is installed without processing (e.g., forming a groove) to create a space for the vapor chamber. Furthermore, according to this embodiment, even such a thin vapor chamber maintains thermal performance while being strong and resistant to deformation.

[0100] Meanwhile, the outer peripheral joining portion 13 of the first sheet 10 and the outer peripheral joining portion 23 of the second sheet 20 are arranged so as to overlap, and are joined together by a joining means such as diffusion bonding or brazing. As a result, an enclosed space 2 is formed between the first sheet 10 and the second sheet 20.

[0101] 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 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 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 flow path 3 through which the condensate flows.

[0102] Here, it is preferable that the cross-sectional shape of the condensate flow path 3 be flattened in accordance with the thinning of the vapor chamber 1. This can increase the capillary force, allowing the condensate to move more smoothly, making it possible to maintain a high level of heat transport capacity. More specifically, it is preferable that the ratio (aspect ratio) expressed by the value obtained by dividing the width of the condensate flow path 3 by the height be 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 or more and 300 μm or less. If the width is smaller than 10 μm, the flow path resistance increases, which may result in a decrease in transport capacity. On the other hand, if the width is larger than 300 μm, the capillary force decreases, which may result in a decrease in transport capacity. Furthermore, the height of the condensate flow path 3, which corresponds to the depth G of the liquid flow path groove 15a in this embodiment, is preferably 5 μm or more and 200 μm or less. 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.

[0103] 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 quadrangular such as square, rectangle, or trapezoid, triangular, semicircular, with a semicircular bottom, with a semi-elliptical bottom, or a combination of these. It may also be crescent-shaped.

[0104] In this embodiment, liquid flow path grooves 14a and 15a are provided only in first sheet 10, and therefore the height of the condensate flow path is based on the depth of liquid flow path grooves 14a and 15a, but this is not limiting and liquid flow path grooves may also be provided in second sheet 20. In this case, the liquid flow path grooves of the first sheet and the second sheet overlap to form the condensate flow path, and the height of the condensate flow path corresponds to the sum of the depths of both liquid flow path grooves.

[0105] In this way, when liquid flow channel grooves are provided in the first sheet and the second sheet and then stacked to form a condensate flow channel, the condensate flow channel can be configured as shown in Figures 20(a) to 20(c). In the example of FIG. 20(a), the liquid flow path grooves of the first sheet and the second sheet have the same width and are arranged at the same positions. 20(b) shows an example in which the width of the liquid flow channel grooves in the second sheet is larger than that of the first sheet, but the positions of the grooves are the same. In this example, a convex portion, indicated by P, is formed in the condensate flow channel, improving the capillary force and increasing the force that moves the condensate (the supply force of the condensate). 20(c) shows an example in which the liquid flow channel grooves on the first and second sheets have the same width but are positioned offset from each other. In this example, too, a protrusion, indicated by P, is formed in the condensate flow channel, improving the capillary force and increasing the force that moves the condensate (the condensate supply force).

[0106] As described above, the condensate flow passage 3 is formed with the communication openings 14c and 15c. This allows the multiple condensate flow passages 3 to communicate with each other, equalizing the condensate and ensuring efficient movement of the condensate. Furthermore, the communication openings 14c and 15c, which are adjacent to the steam flow passage 4 and communicate between the steam flow passage 4 and the condensate flow passage 3, allow the condensate generated in the steam flow passage 4 to smoothly move to the condensate flow passage 3 and also allow the steam generated in the condensate flow passage 3 to smoothly move to the steam flow passage 4, thereby enabling the working fluid to move quickly.

[0107] Furthermore, the condensate flow path 3 formed by the peripheral liquid flow path section 14 and the peripheral liquid flow path section 24 is preferably formed in a continuous ring shape along the edge of the sealed space 2. In other words, the condensate flow path 3 formed by the peripheral liquid flow path section 14 and the peripheral liquid flow path section 24 preferably 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.

[0108] In this embodiment, as explained above, 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 provided 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 provided.

[0109] The opening of the steam flow channel groove 16 in the first sheet 10 and the opening of the steam flow channel groove 26 in the second sheet 20 overlap so as to face each other, forming a flow channel, which becomes the steam flow channel 4. Here, it is preferable that the cross section 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 to maintain a high level of heat transport capacity. More specifically, the width W of the vapor flow path 4 shown in FIG. B , height H B In W B H B The ratio (aspect ratio) expressed by the value obtained by dividing by is preferably 2.0 or more. From the viewpoint of ensuring even higher heat transport capacity, the ratio is more preferably 4.0 or more.

[0110] As can be seen from FIG. 17, the openings of the steam flow path communication grooves 17 of the first sheet 10 and the openings of the steam flow path communication grooves 27 of the second sheet 20 overlap to face each other, forming a flow path, and the ends of the multiple steam flow paths 4 formed by the steam flow path grooves 16 and 26 are connected to each other, providing a flow path for balanced movement of the working fluid.

[0111] 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. Figure 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 mainly flows, 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.

[0112] The steam flow path 4 and the condensate flow path 3 allow the working fluid in the form of vapor and condensate to move in the steam flow path 4, thereby 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.

[0113] Furthermore, in the vapor chamber 1, two straight sections 6 in which the condensate flow path 3 and the vapor flow path 4 extend in different directions 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 is subject to restrictions on placement and cannot form a flow path that is only linear, the curved section 7 makes it possible to efficiently transfer heat generated from the heat source to a remote location.

[0114] This 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 direction changes from the x direction to the y direction and from the y direction to the x direction.

[0115] In this embodiment, the cross-sectional area (width in this embodiment) of the vapor flow path 4 is made larger at the curved portion 7 than at the straight portion 6. This reduces the flow resistance at the curved portion 7, where the flow resistance increases due to the curvature of the vapor flow path 4, 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 cross-sectional area of ​​the vapor flow path 4 at the curved portion 7 may be constant at least within the range of the curved portion 7. This reduces the flow loss of the working fluid due to the expansion and contraction of the flow path cross-section. Here, the "cross-sectional area of ​​the flow path" is the cross-sectional area of ​​the flow path in a plane perpendicular to the direction in which the flow path extends.

[0116] The means, degree and concept for increasing the flow path cross-sectional area (width in this embodiment) of the steam flow path 4 in the curved portion 7 are the same as those explained for the curved portion 18c of the first sheet 10 above.

[0117] 21, in the curved portion 7 of this embodiment, the condensate flow path 3 and the steam flow path 4 are configured so 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.

[0118] In this embodiment, the plurality of grooves are curved to form concentric arcs. However, the center positions of the arcs may be offset, and the curved portion 7 is configured such that the longer the length of each flow channel groove, the larger the radius of curvature.

[0119] When multiple curved flow paths are arranged in a vapor chamber, the flow path lengths are shorter toward the inside and longer toward the outside, resulting in a large difference in flow resistance between the inside and outside. This difference in flow resistance can lead to an imbalance in the movement of the working fluid in the vapor chamber, which can be a factor in preventing sufficient heat transport capacity. In contrast, by using a configuration with the above-described radius of curvature, it is possible to mitigate the difference in flow resistance between the inside and outside, particularly in the vapor flow path 4. This improves the balance of the movement of the working fluid and further increases heat transport capacity.

[0120] However, the present invention is not limited to this, and the radius of curvature of the plurality of steam flow paths 4 at the curved portion 7 may be the same, following the example of FIG.

[0121] Furthermore, 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 with a pitch different from that of the straight portion 6. In this case, the pitch of the communication openings in the curved portion may be larger or smaller than the pitch of the curved openings in the straight portion. Which of these configurations is adopted can be determined by comprehensively determining the configuration that can reduce flow resistance, taking into account the effects of the overall shape of the vapor chamber, the position of the heat source, and the like. Alternatively, in the curved portion 7, the communication openings 14c and 15c do not need to be provided 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 sections is greater than the pitch of the communication openings in the straight sections, the working fluid flowing through the steam flow path 4 can be prevented from entering the communication openings 14c and 15c at the curved sections 7. In the curved sections 7, the working fluid moving through the steam flow path 4 is forced to flow directly into the communication openings 14c and 15c due to its flow direction, which tends to cause the steam to enter the condensate flow path 3 and increase flow resistance 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 path 4 at the curved sections 7 or by eliminating the communication openings 14c and 15c that contact the steam flow path 4, it is possible to prevent such an increase in flow resistance, further reducing the difference in flow resistance between the steam flow paths 4, improving the balance of the movement of the working fluid, and increasing heat transport capacity. On the other hand, when the pitch of the communication openings in the curved sections is smaller than that of the communication openings in the straight sections, the steam flowing through the steam flow grooves (steam flow paths) tends to condense more easily because the steam hits the wall surfaces more strongly in the curved sections. In this case, by making the pitch of the communication openings in the curved sections smaller than that of the communication openings in the straight sections, the number of communication openings can be increased, allowing condensate to smoothly flow into the liquid flow grooves (condensate flow paths) and preventing the steam flow paths from being blocked by condensate. This can prevent an increase in flow resistance, further reduce the difference in flow resistance between the steam flow grooves (steam flow paths), improve the balance of working fluid movement, and potentially increase heat transport capacity.

[0122] Alternatively, instead of the pitch, the length of the wall between adjacent communication openings in the curved section (the length in the direction along the flow path) may be configured to be greater or smaller than the length of the wall in the straight section. In this case, the length of the wall belonging to the curved section does not need to be constant and may vary from wall to wall. In this case, the relationship in magnitude 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.

[0123] On the other hand, as shown in Figure 1, the inner surfaces 10a and 20a of the injection sections 12 and 22 overlap so that they face each other, and the opening on the opposite side of the bottom of the injection groove 22a of the second sheet 20 is blocked by the inner surface 10a of the injection section 12 of the first sheet 10, forming an injection flow path 5 that connects the outside with the hollow section 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 into the sealed space 2 from the injection flow path 5, the injection flow path 5 is closed, so that in the final form of the vapor chamber 1, the sealed space 2 is not in communication with the outside.

[0124] 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.

[0125] The vapor chamber as described above can be fabricated, for example, as follows.

[0126] 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 grooves 14a, liquid flow path grooves 15a, vapor flow path grooves 16, vapor flow path grooves 26, vapor flow path communication grooves 17, and vapor flow path communication grooves 27 described above are formed in these sheets by half etching. Here, half etching refers to forming grooves and depressions by removing material by etching partway through the thickness direction without etching completely through the thickness direction.

[0127] 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 surfaces 10a and 20a facing each other and temporarily joined together. The method of temporary joining is not particularly limited, but examples include resistance welding, ultrasonic welding, and adhesion with an adhesive. After temporary attachment, these sheets are then bonded permanently by diffusion bonding. Brazing may also be used for bonding. However, in the case of a thin vapor chamber like the present embodiment, the flow path is narrow, so if brazing is used, there is a risk that the brazing material will penetrate into the flow path. Furthermore, as described above, strong capillary forces act on the flow path, so 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 preferred.

[0128] After bonding, a vacuum is drawn through the formed injection channel 5 to reduce the pressure inside the hollow portion. After that, the working fluid is injected into the reduced pressure hollow portion through the injection channel 5, and the working fluid enters the hollow portion. Then, the injection channel 5 is closed by melting the injection portions 12 and 22 with a laser or by crimping. This creates a sealed space 2, inside which the working fluid is stably held, forming the vapor chamber 1.

[0129] Next, the action of vapor chamber 1 when it is activated will be described. Figure 22 shows a schematic diagram of vapor chamber 1 disposed inside portable terminal 40, which is one form of electronic device. Here, vapor chamber 1 is shown by a dotted line because it is disposed inside housing 41 of portable terminal 40. Portable terminal 40 is configured with housing 41 that houses various electronic components, and display unit 42 that is exposed so that images can be seen to the outside through an opening in housing 41. Electronic component 30 to be cooled by vapor chamber 1 is disposed within housing 41 as one of these electronic components.

[0130] The vapor chamber 1 is installed inside the housing of a mobile terminal or the like, and is attached to an electronic component 30, such as a CPU, which is the object to be cooled. The electronic component 30 is attached to the outer surface 10b or outer surface 20b of the vapor chamber 1 directly, or via a highly thermally conductive adhesive, sheet, tape, or the like.

[0131] Figure 23 shows a diagram for explaining the behavior of the working fluid. For ease of explanation, this diagram is taken from the same perspective as Figure 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 reaches the condensate present in the sealed space 2 near the electronic components 30. The condensate absorbs the heat and evaporates, thereby cooling the electronic components 30.

[0132] 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 the heat source, without vibrating, although this is not shown. At this time, the steam flow path 4 includes the curved portion of the curved section 7, but because the curved section 7 has the above-described configuration, flow resistance is reduced and well-balanced even if the flow path lengths are different, and the working fluid moves smoothly through the steam flow path 4. This makes it possible to demonstrate high heat transport capacity. As the working fluid moves, it 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 absorb heat from the vapor and transfer the heat to the housing of the portable terminal device in contact with their outer surfaces 10b and 20b, respectively, and the heat is finally released into the outside air. The working fluid absorbs heat as it moves through the vapor flow path 4 and is condensed and liquefied.

[0133] A portion of the condensate generated in the steam flow path 4 moves from the communication openings etc. to the condensate flow path 3. Since the condensate flow path 3 in this embodiment is provided with the communication openings 14c and 15c, the condensate is distributed to the plurality of condensate flow paths 3 through these communication openings 14c and 15c.

[0134] The condensate that has entered the condensate flow path 3 moves toward the heat source, electronic component 30, due to the capillary force of the condensate flow path, as indicated by the dotted straight arrow in Fig. 23. It is then vaporized again by the heat from the heat source, electronic component 30, and the above process is repeated.

[0135] As described above, the vapor chamber 1 allows the working fluid to move smoothly and efficiently through the vapor flow path and the high capillary force in the condensate flow path, 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 is subject to placement restrictions and is unable to form a flow path that is only linear, the heat generated from the heat source can be efficiently transferred to a remote location. Furthermore, the curved section 7 is configured to reduce the flow resistance in the multiple steam flow paths 4 as described above, and to reduce the difference in flow resistance as needed, so that the working fluid can be moved in a balanced manner, thereby increasing the heat transport capacity.

[0136] 24 to 31 are diagrams illustrating a vapor chamber 201 according to the second embodiment. Fig. 24 is an external perspective view of the vapor chamber 201, and Fig. 25 is an exploded perspective view of the vapor chamber 201.

[0137] 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 (by diffusion bonding, brazing, or the like), thereby forming 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 a working fluid is sealed in this hollow space to form the sealed space 202.

[0138] 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 the front and back sides, and includes 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.

[0139] The first sheet 210 includes a main body 211 and an injection part 212. The main body 211 is a sheet-like part that forms an enclosed space in which the working fluid moves, and in this embodiment, is a rectangle with arcuate (so-called R) corners 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 main 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.

[0140] 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 the front and back sides, and includes 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.

[0141] The second sheet 220 also has a main body 221 and an injection portion 222 .

[0142] In this embodiment, the third sheet 230 is a sheet that is 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) is a view of the surface that overlaps the second sheet 220, and Fig. 26(b) is a view of the surface that overlaps the first sheet 210. Fig. 27 shows a cross section taken along the line XXIV-XXIV in Fig. 26(a), and Fig. 28 shows a cross section taken along the line XXV-XXV in Fig. 26(a).

[0143] 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 in 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 that overlaps first sheet 210. Injection groove 232a can be considered to be the same as injection groove 22a described above.

[0144] The main body 231 is provided with an outer periphery joining portion 233 , an outer periphery liquid flow path portion 234 , an inner liquid flow path portion 235 , a steam flow path slit 236 , and a steam flow path communication groove 237 .

[0145] The outer peripheral joining portion 233 is a portion formed along the outer periphery of the main body 231. One surface of the outer peripheral joining portion 233 is overlapped and joined (diffusion bonding, brazing, etc.) to the surface of the first sheet 210, and the other surface is overlapped and joined (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 a 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.

[0146] The peripheral liquid flow path section 234 functions as a liquid flow path section and is a portion 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 joining 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 peripheral liquid flow path section 234 and the liquid flow path grooves 234a provided therein can be considered to be similar to the outer peripheral liquid flow path section 14 and the liquid flow path grooves 14a described above.

[0147] The inner liquid flow path section 235 also functions as a liquid flow path section, and is a section 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 in the main body 231 so as to have a curved section and extend inside the ring of the annular outer peripheral liquid flow path section 234. A plurality of (five in this embodiment) inner liquid flow path sections 235 are arranged in a direction different from the extending direction and are disposed between the steam flow path slits 236.

[0148] 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 the same as the inner liquid flow path section 15 and the liquid flow path groove 15a described above. In this embodiment, the liquid flow path grooves 235a are provided only on the surface facing the second sheet 220, but in addition, liquid flow path grooves may also be provided on the surface facing the first sheet 210.

[0149] The steam flow path slits 236 are portions through which the working fluid in the vapor and condensed liquid states move, and are slits that constitute the steam flow paths 4. The steam flow path slits 236 are formed in the main body 231 on the inside of the ring of the annular outer peripheral liquid flow path section 234, and are configured as slits having curved portions. More specifically, the steam flow path slits 236 in this embodiment are slits formed between adjacent inner liquid flow path sections 235, and between the outer peripheral liquid flow path section 234 and the inner liquid flow path section 235. Therefore, the steam flow path slits 236 penetrate the third sheet 230 in the thickness direction (z direction). A plurality of (six in this embodiment) steam flow path 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 path portion 234, the inner liquid flow path portion 235, and the steam flow path slits 236 are alternately repeated.

[0150] Such a steam flow path slit 236 can be considered to be similar to the steam flow path 4 formed by combining the steam flow path groove 16 and the steam flow path groove 26 described above.

[0151] In this embodiment, the cross-sectional shape of the steam flow path slit 236 is formed by overlapping portions of an ellipse, with the center in the thickness direction protruding, but 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.

[0152] The steam flow path communication groove 237 is a groove that forms a flow path that communicates the multiple steam flow path slits 236. This makes it possible to balance the movement of the working fluid that occurs in the steam flow path in the direction in which the inner liquid flow path section 235 extends. 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 provided by the many liquid flow path grooves 234a and 235a to be used efficiently.

[0153] The steam flow path communication grooves 237 in this embodiment are formed between both ends of the inner liquid flow path section 235 in the extending direction and both ends of the steam flow path slits 236 in the extending direction, and the outer circumferential liquid flow path section 234. The steam flow path communication grooves 237 only need to be able to communicate with adjacent steam flow path slits 236, and the shape thereof is not particularly limited, but can be considered to be similar to a flow path formed by overlapping the above-mentioned steam flow path communication grooves 17 and 27.

[0154] 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 vapor flow path 4 have straight portions and curved portions in the vapor chamber 201 and the sealed space 202. The concepts of these straight portions and curved portions are the same as those explained above.

[0155] Such a third sheet 230 can be produced by etching each side separately, etching both sides simultaneously, pressing, cutting, or the like.

[0156] Figures 29 to 31 are diagrams illustrating 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 is a cross section taken along the line XXVI-XXVI in Figure 24, and Figure 30 is an enlarged view of a portion of Figure 29. Figure 31 is a cross section taken along the line XXVIII-XXVIII in Figure 24.

[0157] 24 and 29 to 31, the first sheet 210, the second sheet 220, and the third sheet 230 are overlappingly arranged 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 which the liquid flow path 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 path grooves 234a and 235a are arranged) are overlappingly arranged. In a similar manner, the injection portions 212, 222, and 232 of each sheet are also overlappingly arranged.

[0158] As a result, a sealed space 202 surrounded by the first sheet 210, the second sheet 220, and the third sheet 230 is formed between the first sheet 210 and the second sheet 220. A condensate flow path 3 and a vapor flow path 4 are formed in this sealed space 202. The same concept as that of the vapor chamber 1 described above can be applied to the configurations of the condensate flow path 3 and the vapor flow path 4 in this sealed space 202.

[0159] In the above embodiment, a vapor chamber having a curved portion at the intersection of two straight portions intersecting at 90 degrees to form an L-shape has been described. However, the shape of the curve is not limited to this, and the above-described curved portion can be applied to other shapes as well. For example, the curved portion can be applied to an intersection of two straight portions extending in a direction intersecting a T-shape, an intersection of two straight portions extending in a direction intersecting a crisscross, an intersection of two straight portions intersecting at an acute angle (an angle smaller than 90 degrees) to form a V-shape, and an intersection of two straight portions intersecting at an obtuse angle (an angle larger than 90 degrees) to form a V-shape. [Explanation of symbols]

[0160] 1 Vapor Chamber 2 Closed space 3 Condensate flow path 4 Steam flow path 10 First Sheet 11 Main unit 12 Injection part 13 Peripheral joint 14 Peripheral liquid flow path section 14a Liquid flow groove 14c Communication opening 15 Inner liquid flow path section 15a Liquid flow groove 15c Communication opening 16 Steam flow groove 17 Steam flow path connecting groove 20 Second Sheet 21 Main Unit 22 Injection part 23 Peripheral joint 24 Peripheral liquid flow path section 25 Inner liquid flow path section 26 Steam flow channel groove 27 Steam flow path connecting groove 230 Third seat 236 Steam flow slit

Claims

[Claim 1] 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 plurality of vapor flow paths through which the working fluid moves in a vapor and condensate state; a linear portion where the steam flow path extends linearly; a curved portion at which the extension direction of the steam flow path changes, the steam flow path has a larger flow path cross-sectional area at the curved portion than at the straight portion, the width of the steam flow path at the curved portion is greater than the width of the straight portion by 10% or more and 100% or less, The width of the steam flow path is changed by a tapered inclined surface at a connection portion between the curved portion and the straight portion. Vapor chamber.

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