WO2022230295A1 - Thermal diffusion device - Google Patents

Abstract

A vapor chamber 1, which is an embodiment of this thermal diffusion device, comprises: a casing 10 having a first inner wall surface 11a and a second inner wall surface 12a that are opposed to each other in a thickness direction; an operating medium 20 enclosed in an inner space of the casing 10; and a wick 30 located in the inner space of the casing 10. The wick 30 extends in a direction perpendicular to the thickness direction and has a portion in contact with the first inner wall surface 11a and the second inner wall surface 12a of the casing 10. A vapor flow channel 50 is formed in the inner space of the casing 10. The planar shape of the casing 10 as viewed in the thickness direction has a first side 61 and a second side 62 that form an interior angle equal to or greater than 180 degrees. In the inner space of the casing 10, further provided is a capillary structure 70 having a first part 71 close to the first side 61 or to the second side 62, and a second part 72 in contact with the wick 30.

Description

heat spreading device

The present invention relates to heat diffusion devices.

In recent years, the amount of heat generated has increased due to the high integration and high performance of devices. In addition, as products become smaller, heat generation density increases, so heat dissipation measures have become important. This situation is particularly pronounced in the field of mobile terminals such as smartphones and tablets. A graphite sheet or the like is often used as a heat countermeasure member, but its heat transfer capacity is not sufficient, so the use of various heat countermeasure members has been investigated. Among them, as a heat diffusion device capable of diffusing heat very effectively, the use of a vapor chamber, which is a planar heat pipe, is being studied.

The vapor chamber has a structure in which a working medium and a wick that transports the working medium by capillary force are sealed inside the housing. The working medium absorbs heat from the heating element in the evaporating portion that absorbs heat from the heating element, evaporates in the vapor chamber, moves in the vapor chamber, is cooled, and returns to the liquid phase. The working medium that has returned to the liquid phase moves again to the evaporating portion on the heating element side by the capillary force of the wick, and cools the heating element. By repeating this, the vapor chamber can operate independently without external power, and heat can be two-dimensionally diffused at high speed by utilizing the latent heat of vaporization and latent heat of condensation of the working medium.

Patent Literature 1 discloses a vapor chamber in which a peripheral fluid passage portion through which the working fluid flows is formed over the entire peripheral edge of the first metal sheet or the second metal sheet.

JP 2019-66175 A

In the vapor chamber described in Patent Document 1, a liquid flow path portion (wick) through which the liquid working fluid passes is formed on the entire surface of the vapor chamber when viewed from above (see FIG. 4 of Patent Document 1).
Further, the shape of the wick is shown on the premise that the shape of the vapor chamber when viewed from above is rectangular, and the heat source is positioned at the center of the rectangle (see each figure of Patent Document 1).

If the wick is formed on the entire surface of the vapor chamber when viewed from above, the proportion of the vapor flow path through which the vapor of the working fluid passes is relatively reduced. A problem arises that the maximum heat transfer rate decreases when the percentage of the portion through which the steam passes is low.
In addition, since the steam flow path is divided by the wick, there arises a problem that uniformity of heat is lowered. Furthermore, forming the wick on the entire surface also raises the problem that the cost associated with the formation of the wick increases.

Therefore, instead of forming the wick over the entire surface, it is being considered to form the wick only where it is considered necessary.
This is the case where the wick is not formed on the entire surface, and the shape of the vapor chamber when viewed from above is not a rectangle, but a shape having first and second sides forming an interior angle of 180° or more (hereinafter also referred to as a deformed shape). Consider the case of In this case, depending on the direction in which the vapor chamber is used (orientation relative to the direction in which gravity is applied), a liquid pool may occur near the first side or the second side. Liquid pools formed near the first side or the second side cannot be collected by the wick, so the amount of liquid transported is reduced, resulting in a problem of a decrease in the maximum heat transport amount.

It should be noted that the above problem is not limited to vapor chambers, but is common to heat diffusion devices capable of diffusing heat with a configuration similar to that of vapor chambers.

The present invention has been made to solve the above problems, and provides a heat diffusion device that can increase the maximum heat transfer rate and heat uniformity by increasing the ratio of steam flow paths. for the purpose.

A heat diffusion device of the present invention comprises a housing having a first inner wall surface and a second inner wall surface facing each other in a thickness direction, a working medium enclosed in the internal space of the housing, and a and a wick disposed, the wick having a portion in contact with the first inner wall surface and the second inner wall surface of the housing along a direction perpendicular to the thickness direction, and A steam flow path is formed in the internal space, and the planar shape of the housing viewed from the thickness direction is a shape having first and second sides forming an interior angle of 180° or more, The interior space of the housing further includes a capillary structure having a first portion adjacent to the first side or the second side and a second portion in contact with the wick.

According to the present invention, it is possible to provide a heat diffusion device that can increase the proportion of the steam flow path, increase the maximum heat transfer amount, and improve the heat uniformity.

FIG. 1 is a perspective view schematically showing an example of the heat diffusion device of the present invention. FIG. 2A is a plan view schematically showing an example of the vapor chamber according to the first embodiment of the invention. FIG. FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A. FIG. 2C is a cross-sectional view taken along line BB of FIG. 2A. FIG. 2D is a cross-sectional view taken along line CC of FIG. 2A. FIG. 3A is a plan view schematically showing an example of vapor chambers with different orientations of capillary structures. FIG. 3B is a plan view schematically showing an example of vapor chambers with different orientations of capillary structures. FIG. 4 is a plan view schematically showing an example of a vapor chamber in which the second end of the capillary structure is in contact with multiple wicks. FIG. 5A is a plan view schematically showing an example of a vapor chamber having a housing with a different planar shape. FIG. 5B is a plan view schematically showing an example of a vapor chamber having a housing with a different planar shape. FIG. 5C is a plan view schematically showing an example of a vapor chamber having a housing with a different planar shape. FIG. 5D is a plan view schematically showing an example of a vapor chamber having a housing with a different planar shape. FIG. 5E is a plan view schematically showing an example of a vapor chamber having a housing with a different planar shape. FIG. 6A is a cross-sectional view schematically showing an example in which microchannels have different cross-sectional shapes. FIG. 6B is a cross-sectional view schematically showing an example in which microchannels have different cross-sectional shapes. FIG. 6C is a cross-sectional view schematically showing an example in which the microchannel has a different cross-sectional shape. FIG. 7 is a cross-sectional view schematically showing an example in which microchannels are provided on both the first inner wall surface and the second inner wall surface of the housing. FIG. 8A is a perspective view schematically showing an example in which a space sandwiched by additional parts is used as a capillary structure. FIG. 8B is a perspective view schematically showing an example in which a porous body has a capillary structure. FIG. 9A is a plan view schematically showing an example of a vapor chamber in which pillars are provided inside a housing. FIG. 9B is a cross-sectional view taken along line DD of FIG. 9A. FIG. 10 is a plan view schematically showing an example of a vapor chamber in which the wick does not have a liquid phase flow path.

The heat diffusion device of the present invention will be described below.
However, the present invention is not limited to the following configurations, and can be appropriately modified and applied without changing the gist of the present invention. It should be noted that a combination of two or more of the individual preferred configurations of the invention described below is also the invention.

A heat diffusion device of the present invention comprises a housing having a first inner wall surface and a second inner wall surface facing each other in a thickness direction, a working medium enclosed in the internal space of the housing, and a and a wick disposed, the wick having a portion in contact with the first inner wall surface and the second inner wall surface of the housing along a direction perpendicular to the thickness direction, and the inside of the housing. A steam flow path is formed in the space, and the planar shape of the housing viewed from the thickness direction is a shape having first and second sides forming an internal angle of 180° or more.

A vapor chamber will be described below as an example of an embodiment of the heat diffusion device of the present invention. The heat diffusion device of the present invention can also be applied to heat diffusion devices such as heat pipes.

FIG. 1 is a perspective view schematically showing an example of the heat diffusion device of the present invention.

The vapor chamber 1 shown in FIG. 1 includes a hollow housing 10 that is hermetically sealed. As shown in FIG. 1, a heat source HS, which is a heating element, is arranged on the outer wall surface of the housing 10 . Examples of the heat source HS include electronic components of electronic equipment, such as a central processing unit (CPU).

The vapor chamber 1 is planar as a whole. That is, the housing 10 is planar as a whole. Here, the “planar shape” includes a plate shape and a sheet shape, and the dimension in the width direction X (hereinafter referred to as width) and the dimension in the length direction Y (hereinafter referred to as length) are the thickness direction Z It means a shape that is considerably large with respect to its dimensions (hereafter referred to as thickness or height). For example, it means a shape whose width and length are 10 times or more, preferably 100 times or more, the thickness.

The size of the vapor chamber 1, that is, the size of the housing 10 is not particularly limited. The width and length of the vapor chamber 1 can be appropriately set according to the application. The width and length of the vapor chamber 1 are, for example, 5 mm or more and 500 mm or less, 20 mm or more and 300 mm or less, or 50 mm or more and 200 mm or less. The width and length of the vapor chamber 1 may be the same or different.
When the vapor chamber has an irregular shape, the width and length of the vapor chamber are defined as maximum values in the width direction and the length direction.

The housing 10 is preferably composed of a first sheet 11 and a second sheet 12 that face each other and whose outer edges are joined. Materials for the first sheet 11 and the second sheet 12 are not particularly limited as long as they have properties suitable for use as a vapor chamber, such as thermal conductivity, strength, softness, and flexibility. The material that constitutes the first sheet 11 and the second sheet 12 is preferably a metal, such as copper, nickel, aluminum, magnesium, titanium, iron, or an alloy containing them as a main component, and copper is particularly preferable. is. The materials forming the first sheet 11 and the second sheet 12 may be the same or different, but are preferably the same.

When the housing 10 is composed of the first sheet 11 and the second sheet 12, the first sheet 11 and the second sheet 12 are joined together at their outer edges. Such bonding methods are not particularly limited, but laser welding, resistance welding, diffusion bonding, brazing, TIG welding (tungsten-inert gas welding), ultrasonic bonding, or resin sealing can be used, for example. Preferably laser welding, resistance welding or brazing can be used.

The thicknesses of the first sheet 11 and the second sheet 12 are not particularly limited, but each is preferably 10 μm or more and 200 μm or less, more preferably 30 μm or more and 100 μm or less, still more preferably 40 μm or more and 60 μm or less. The thicknesses of the first sheet 11 and the second sheet 12 may be the same or different. Further, the thickness of each sheet of the first sheet 11 and the second sheet 12 may be the same over the entire area, or may be thin in part.

The shapes of the first sheet 11 and the second sheet 12 are not particularly limited. For example, the first sheet 11 may have a flat plate shape with a constant thickness, and the second sheet 12 may have a shape in which the outer edge portion is thicker than the portions other than the outer edge portion.

Alternatively, the first sheet 11 may have a flat plate shape with a constant thickness, and the second sheet 12 may have a constant thickness and a portion other than the outer edge with respect to the outer edge may be convex outward. good. In this case, a recess is formed in the outer edge of the housing 10 . Therefore, the concave portion of the outer edge can be used when mounting the vapor chamber. Also, other components can be placed in the recesses of the outer edge.

Although the thickness of the entire vapor chamber 1 is not particularly limited, it is preferably 50 μm or more and 500 μm or less.

The planar shape of the housing 10 as seen from the thickness direction Z is a shape having first and second sides forming an internal angle of 180° or more, and is preferably a polygonal shape. The shape is not limited as long as it has vertices forming an interior angle of 180° or more. For example, it may be L-shaped, C-shaped (U-shaped), or stepped. Further, the housing 10 may have a space (through-hole) inside the planar figure. The planar shape of the housing 10 may be a shape according to the use of the vapor chamber, the shape of the location where the vapor chamber is installed, and other parts existing nearby.
Also, the angle formed by the first side and the second side may be 180° or more and less than 360°, for example, 225° or more and 315° or less.
A specific example of the planar shape of the housing 10 will be described later.

The heat spreading device of the present invention further comprises a capillary structure in the inner space of the housing.
A first portion of the capillary structure is adjacent to the first side or the second side, and a second portion of the capillary structure is in contact with the wick.
Preferably, the capillary structure has a first end and a second end and is shaped to extend from the first end to the second end. Preferably, the first end corresponds to the first part of the capillary structure and the second end corresponds to the second part of the capillary structure.

Specific embodiments of the heat spreading device of the present invention are shown below.
Each embodiment shown below is an example, and it goes without saying that partial replacement or combination of configurations shown in different embodiments is possible. In the second and subsequent embodiments, descriptions of matters common to the first embodiment will be omitted, and only different points will be described. In particular, similar actions and effects due to similar configurations will not be mentioned sequentially for each embodiment.

In the following description, when each embodiment is not particularly distinguished, it is simply referred to as "the heat diffusion device of the present invention".

The drawings shown below are schematic, and their dimensions and aspect ratio may differ from the actual product.

[First embodiment]
In the first embodiment of the present invention, the capillary structure is a plurality of grooves provided on at least one of the first inner wall surface and the second inner wall surface of the housing.
The housing has an evaporator for evaporating the working medium, and the end of the wick is located in the evaporator. Also, the first side is positioned farther from the evaporator than the second side.
The capillary structure is shaped having a first end and a second end and extending from the first end to the second end. The first end corresponds to the first part of the capillary structure and the second end corresponds to the second part of the capillary structure.
The first end, which is the first part of the capillary structure, is in contact with the first side, and the second end, which is the second part of the capillary structure, is in contact with one wick.
Also, the wick includes a first porous body and a second porous body. In the wick, a liquid phase flow path is formed by providing a space between the first porous body and the second porous body along the direction in which the first porous body and the second porous body extend.

As the first porous body and the second porous body, for example, metal porous membranes, meshes, non-woven fabrics, sintered bodies, and other porous bodies formed by etching or metal working are used. The mesh that is the material of the wick may be composed of, for example, a metal mesh, a resin mesh, or a surface-coated mesh thereof, preferably a copper mesh, a stainless steel (SUS) mesh, or a polyester mesh. . The sintered body that is the material of the wick may be composed of, for example, a metal porous sintered body or a ceramic porous sintered body, preferably a porous sintered body of copper or nickel. .
Other porous bodies used as wick materials may be composed of, for example, metal porous bodies, ceramic porous bodies, resin porous bodies, or the like.
A mesh, a nonwoven fabric, and a sintered body are also included in the porous body in this specification.

FIG. 2A is a plan view schematically showing an example of the vapor chamber according to the first embodiment of the invention. FIG. 2B is a cross-sectional view along line AA of FIG. 2A, FIG. 2C is a cross-sectional view along line BB of FIG. 2A, and FIG. 2D is a cross-sectional view along line CC of FIG. 2A.
In this specification, any plan view of the vapor chamber as shown in FIG. 2A is a schematic diagram showing the internal structure of the vapor chamber, and is a diagram showing through either the first sheet or the second sheet. It can be said that there is.
The housing 10 has a first inner wall surface 11a and a second inner wall surface 12a facing each other in the thickness direction Z, as shown in FIGS. 2B, 2C and 2D. As illustrated in FIG. 1, the housing 10 is preferably constructed from opposed first and second sheets 11 and 12 joined at their outer edges. As shown in FIG. 2B, the vapor chamber 1 is further arranged between the working medium 20 enclosed in the internal space of the housing 10 and the first inner wall surface 11a and the second inner wall surface 12a of the housing 10. and a wick 30 that

The wick 30 includes a first porous body 41 and a second porous body 42 . These porous bodies function as wicks that transport the working medium 20 by capillary force.
In addition, the first porous body 41 and the second porous body 42 constituting the wick 30 have portions in contact with the first inner wall surface 11a and the second inner wall surface 12a of the housing 10 along the direction perpendicular to the thickness direction. . By arranging these porous bodies in the internal space of the housing 10, the mechanical strength of the housing 10 can be ensured and the impact from the outside of the housing 10 can be absorbed.
The thickness of the first porous body 41 and the second porous body 42 that constitute the wick 30 is approximately the same as the thickness of the internal space of the housing.

A steam flow path is formed in the internal space of the housing.
FIGS. 2A and 2B show vapor flow paths 50 through which vapor-phase working medium 20 flows between adjacent wicks 30 .
In each wick 30, between the first porous body 41 and the second porous body 42, the direction in which the first porous body 41 and the second porous body 42 extend (in this embodiment, the length direction Y, the rightmost wick Further, a liquid phase flow path 51 is formed by providing an interval along the width direction X). The liquid-phase channel 51 can be used as a channel through which the liquid-phase working medium 20 flows. By alternately arranging the liquid phase channels and the vapor channels with the first porous body 41 or the second porous body 42 interposed therebetween, the heat transport efficiency can be improved.

As shown in FIG. 2A, the housing 10 is provided with an evaporation portion EP for evaporating the enclosed working medium 20 . A portion of the internal space of the housing 10 that is in the vicinity of the heat source HS and is heated by the heat source HS corresponds to the evaporating section EP.

The working medium 20 is not particularly limited as long as it can cause a gas-liquid phase change in the environment inside the housing 10. For example, water, alcohols, CFC alternatives, etc. can be used. For example, the working medium is an aqueous compound, preferably water.

As shown in FIG. 2A, the wick 30 extends from one end located in the evaporation part EP to the other end in plan view from the thickness direction Z. As shown in FIG. The other end of the wick is a portion away from the evaporator EP and serves as a condensing portion for condensing the evaporated working medium.

The planar shape of the housing 10 shown in FIG. 2A is a so-called L shape.
Moreover, the planar shape of the housing 10 shown in FIG. 2A is a shape having a first side 61 and a second side 62 forming an internal angle of 180° or more. The internal angle between the first side 61 and the second side 62 is an angle indicated by θ in FIG. 2A, which is 270° in this drawing.
The first side 61 is a side located farther from the evaporating part EP than the second side 62 is.
The wick 30 is not formed near the first side 61 and the second side 62 .

Here, the wick 30 is not formed in the vicinity of the first side 61, and due to the shape of the housing 10, depending on the direction in which the vapor chamber is used (the direction with respect to the direction in which gravity is applied), liquid pools may form. It may occur near the first side 61 .
Therefore, the capillary structure 70 exists in the inner space of the housing 10 close to the first side 61 . Due to the existence of the capillary structure 70 , it is possible to guide the liquid pool generated in the vicinity of the first side 61 to the wick 30 . As a result, the amount of liquid transported can be improved, and the maximum heat transport amount can be improved.
Details of the capillary structure are described below.

The capillary structure 70 is a liquid channel through which the liquid-phase working medium 20 flows, but is different from the wick 30 . Since the wick 30 contacts both the first inner wall surface 11a and the second inner wall surface 12a, it is configured to divide the steam flow path. On the other hand, the capillary structure 70 is configured so as not to divide the vapor flow path.

Five capillary structures 70 are shown in FIG. 2A.
Each capillary structure 70 has a first end 71 and a second end 72 .
A first end 71 of the capillary structure 70 is adjacent to the first side 61 .
Proximity here means that the first part (first end) of the capillary structure is positioned closer to the first side than the wick positioned closest to the first side. means If the wick is positioned closer to the first side where the liquid pool is formed than the first part of the capillary structure, the liquid pool is absorbed by the wick instead of the capillary structure, so the capillary structure is provided. has no meaning. Therefore, the capillary structure should be positioned close to the first side.
Also, the first end 71 of the capillary structure 70 may be in contact with the first side 61 .

Also, although the case where the first end 71 of the capillary structure 70 is close to the first side 61 has been described here, the first end 71 of the capillary structure 70 is close to the second side 62 . It may be in contact with the second side 62 .

A second end 72 of capillary structure 70 abuts wick 30 .
FIG. 2A shows a configuration in which the second end 72 of the capillary structure 70 contacts one wick 30 .
FIG. 2A shows an arrow F that introduces the liquid-phase working medium 20 existing near the first side 61 to the wick 30 through the capillary structure 70 .
When the first end 71 of the capillary structure 70 is close to the first side 61 or the second side 62 and the second end 72 is in contact with the wick 30, the first side 61 Alternatively, it absorbs the liquid pool generated near the second side 62 .
The liquid-phase working medium 20 can be introduced into the wick 30 by using the inside of the capillary structure 70 as a liquid channel and allowing the liquid-phase working medium 20 to reach the second end 72 . The liquid-phase working medium 20 introduced into the wick 30 is transported by the wick 30 to the evaporator EP.
That is, it is possible to solve the problem that the maximum amount of heat transport is reduced due to the effect of the liquid pool generated at the position where the wick 30 is not formed.

The capillary structure may be a groove provided in at least one of the first inner wall surface and the second inner wall surface of the housing.
2C and 2D show an example in which the capillary structure 70 is a groove provided in the second inner wall surface 12a of the housing 10. FIG.
Such a capillary structure, which is a groove provided on the inner wall surface of the housing, is also called a microchannel in this specification.
FIG. 2C shows the shape of the microchannel 70 in the portion where the wick 30 is absent.
FIG. 2D shows the shape of the microchannel 70 in the portion overlapping the wick 30 (second porous body 42).

The microchannel 70 is a groove formed by recessing the second sheet 12 forming the housing 10 in the thickness direction. Methods for forming grooves in the second sheet 12 include methods such as etching, pressing, and machining, and the methods are not particularly limited.
Although the cross-sectional shape of the microchannel 70 shown in FIGS. 2C and 2D is rectangular, the shape of the microchannel may be other shapes. Examples of other shapes of microchannels will be described later.

Although the depth of the grooves of the microchannel 70 is not particularly limited, it is preferably 10 μm or more and 30 μm or less.
Moreover, the width of the groove of the microchannel 70 is not particularly limited, but is preferably 30 μm or more and 100 μm or less.
Moreover, it is preferable that a plurality of grooves to be the microchannels 70 are provided.

The microchannel is preferably provided on the inner wall surface of the sheet on the side where the heat source HS is not arranged. In the vapor chamber 1 shown in FIG. 1, the heat source HS is arranged on the first sheet 11 side, so the microchannels 70 are preferably provided by forming grooves in the second sheet 12 .

[Second embodiment]
In the second embodiment of the invention, the orientation of the capillary structure is different from that in the first embodiment.
In the first embodiment, the orientation of the capillary structure 70 is oblique with respect to the width direction X and the length direction Y of the vapor chamber, but the orientation of the capillary structure is different in the second embodiment.
3A and 3B are plan views schematically showing examples of vapor chambers having different orientations of capillary structures.

In the vapor chamber 2A shown in FIG. 3A, the orientation of the capillary structure 70A is parallel to the width direction X of the vapor chamber.
In this form, a liquid flow path can be formed in which the distance from the vicinity of the first side (liquid pool in which the liquid-phase working medium 20 is accumulated) to the evaporator EP is the shortest, which is the combination of the capillary structure 70A and the wick 30. It's like
That is, the orientation of the capillary structure 70A is not determined from the viewpoint of being parallel to the width direction X of the vapor chamber.
The shorter the distance from the reservoir in which the liquid-phase working medium 20 is accumulated to the evaporator EP, the greater the maximum heat transfer amount.

In the vapor chamber 2B shown in FIG. 3B, the orientation of the capillary structure 70B is parallel to the longitudinal direction Y of the vapor chamber.
In this form, the length of the capillary structure 70B is the shortest. That is, the direction of the capillary structure 70B is determined so as to connect the vicinity of the first side (liquid reservoir in which the liquid-phase working medium 20 is accumulated) to the nearest wick 30 by the shortest path.
In other words, the orientation of the capillary structure 70A is not determined from the viewpoint of being parallel to the longitudinal direction Y of the vapor chamber.
The transport amount of the liquid-phase working medium by the capillary structure is smaller than that by the wick. Therefore, it is preferable to shorten the distance over which the liquid is transported by the capillary structure so that the liquid reaches the wick as quickly as possible.
The shorter the length of the capillary structure and the higher the proportion of liquid transported by the wick, the higher the maximum heat transfer.

[Third embodiment]
The third embodiment of the present invention differs from the first embodiment in that the second end of the capillary structure is in contact with a plurality of wicks.
In the first embodiment, the second end 72 of the capillary structure 70 was in contact with one wick 30, whereas in the third embodiment the second end of the capillary structure is in contact with multiple wicks.
FIG. 4 is a plan view schematically showing an example of a vapor chamber in which the second end of the capillary structure is in contact with multiple wicks.

In the vapor chamber 3 shown in FIG. 4, the second end 72 of the capillary structure 70C is in contact with a plurality of wicks, namely wick 30a, wick 30b and wick 30c.
In the vapor chamber 3 shown in FIG. 4, it can be said that the capillary structure 70C is in contact with all the wicks provided in the vapor chamber.
When the capillary structure is in contact with a plurality of wicks, the second end (second portion) of the capillary structure shall mean the entire portion where the capillary structure is in contact with the plurality of wicks.

When the capillary structure is in contact with a plurality of wicks, the liquid-phase working medium can be transported from the capillary structure to each wick, thereby improving heat uniformity.

[Fourth embodiment]
In the fourth embodiment of the present invention, the planar shape of the housing is different from that in the first embodiment.
In the first embodiment, the planar shape of the housing is L-shaped, but as the fourth embodiment, a housing having another shape is exemplified.
5A, 5B, 5C, 5D, and 5E are plan views schematically showing examples of vapor chambers having different planar shapes of casings.

In the vapor chamber 4A shown in FIG. 5A, the planar shape of the housing 10A is partially stepped. The vapor chamber 4A shown in FIG. 5A has a stepped shape at the lower right portion of the housing 10A.
The stepped portion has a first side and a second side, and the interior angle θ between the first side 61A and the second side 62A and the interior angle θ between the first side 61B and the second side 62B are both 270°. ing.

A capillary structure 70D is adjacent to the first side 61A, and a capillary structure 70E is adjacent to the first side 61B.
Capillary structure 70D and capillary structure 70E are each in contact with the same wick 30d.

When the planar shape of the housing is stepped, liquid pools may occur at multiple locations, so providing a capillary structure at each location can improve the maximum heat transfer amount.

A vapor chamber 4B shown in FIG. 5B has a T-shaped planar shape of a housing 10B.
The T-shape has a first side and a second side on the right side and the left side, respectively. are both 270°.

A capillary structure 70F is adjacent to the first side 61C, and a capillary structure 70G is adjacent to the first side 61D.
The capillary structure 70F is in contact with the wick 30e, and the capillary structure 70G is in contact with the wick 30f.

When the planar shape of the housing is T-shaped, liquid pools may occur at multiple locations, so by providing a capillary structure at each location, the maximum amount of heat transport can be improved.

A vapor chamber 4C shown in FIG. 5C has a housing 10C with a planar shape having a space 13 in the plane, that is, a donut shape. Specifically, it is a shape having a quadrilateral space in a quadrilateral plane.
The upper side of the space 13 is the first side 61E, the right side is the second side 62E, and the left side is the second side 62F.
The interior angle θ between the first side 61E and the second side 62E and the interior angle θ between the first side 61E and the second side 62F are both 270°.

A first portion 71' of the capillary structure 70H shown in FIG. 5C is a position close to the first side 61E and is not the end of the capillary structure 70H.
One end of the capillary structure 70H is in contact with the wick 30g, and the other end is in contact with the wick 30h. Both the end portion of the capillary structure 70H contacting the wick 30g and the end portion of the capillary structure 70H contacting the wick 30h are the second portion 72' of the capillary structure 70H.

When the planar shape of the housing is donut-shaped, liquid pools may occur near the sides that make up the space. Heat transport can be improved.

A vapor chamber 4D shown in FIG. 5D has a C-shaped planar shape of a housing 10D. The drawing shows a shape in which the corners of the C shape are right angles.
It has a second side 62G at a position corresponding to the bottom (left side) of the C shape. It has a first side 61G on the upper side and a first side 61H on the lower side.
The internal angle between the upper first side 61G and the second side 62G and the internal angle between the lower first side 61H and the second side 62G are both 270°.

A capillary structure 70I is close to the first side 61G, and a capillary structure 70J is close to the first side 61H.
Capillary structure 70I and capillary structure 70J are in contact with the same wick 30i.
Capillary structure 70I contacts wick 30i on the upper side of wick 30i, and capillary structure 70J contacts wick 30i on the lower side of wick 30i.

The orientation of the capillary structure 70I is parallel to the width direction X of the vapor chamber, and the orientation of the capillary structure 70J is oblique to the width direction X and length direction Y of the vapor chamber.
In this example, the orientations of the plurality of capillary structures are different, but when the capillary structures are provided at a plurality of locations, the orientations may be the same or different. This also applies to other embodiments.

When the planar shape of the housing is C-shaped, liquid pools may occur at a plurality of locations. By providing capillary structures at each location, the maximum amount of heat transport can be improved.
Although two liquid pools are shown in FIG. 5D, the locations of the liquid pools differ depending on the orientation of the vapor chamber. Actually, in the vapor chamber shown in FIG. 5D, when the Y direction faces downward in the vertical direction, a liquid pool occurs near the first side 61G, but near the first side 61H. No liquid stagnant part occurs.

A vapor chamber 4E shown in FIG. 5E has a housing 10E whose planar shape is a crank shape.
In the vapor chamber 4E, both the internal angle between the first side 61I and the second side 62I and the internal angle between the first side 61J and the second side 62J are 270°.

The capillary structure 70K is close to the first side 61I, and the capillary structure 70L is close to the first side 61J.
Capillary structure 70K is in contact with wick 30j and capillary structure 70L is in contact with wick 30k.

When the planar shape of the housing is crank-shaped, liquid pools may occur at a plurality of locations. By providing capillary structures at each location, the maximum amount of heat transport can be improved.
Although two liquid pools are shown in FIG. 5E, the locations where the liquid pools are formed differ depending on the orientation of the vapor chamber. Actually, in the vapor chamber shown in FIG. 5E, when the Y direction faces vertically downward, a liquid pool occurs near the first side 61I, but the liquid accumulates near the first side 61J. No stagnant part occurs.

[Fifth embodiment]
In the fifth embodiment of the present invention, the cross-sectional shape of microchannels, which are grooves provided on the inner wall surface of the housing, differs from that in the first embodiment.
In the first embodiment, the microchannel 70 has a rectangular cross-sectional shape, but the fifth embodiment exemplifies a microchannel of another shape.
6A, 6B, and 6C are cross-sectional views schematically showing examples in which microchannels have different cross-sectional shapes. These figures show the shape of the microchannel in the portion overlapping with the wick 30 (second porous body 42), as in FIG. 2D.

FIG. 6A shows a microchannel 70a having a semicircular cross section.
FIG. 6B shows a microchannel 70b having a triangular cross section.
FIG. 6C shows a microchannel 70c having a trapezoidal cross section.
Each microchannel having such a shape is a groove formed by recessing the second sheet 12 forming the housing 10 in the thickness direction, and all of them act as liquid channels.

The depth of the groove in the microchannel having such a shape is the depth measured at the deepest position of the groove. In the case of the semicircular shape shown in FIG. 6A, the depth of the groove is the radius of the circle, and in the case of the triangular shape shown in FIG. height). For the trapezoidal shape shown in FIG. 6C, the depth of the groove is the distance between the top and bottom sides.
The width of the groove is the width of the portion where the microchannel is exposed. In the case of the semicircular shape shown in FIG. 6A, the width of the groove is the diameter of the circle, and in the case of the triangular shape shown in FIG. 6B, the width of the groove is the length of the base. In the trapezoidal shape shown in FIG. 6C, the width of the groove is the length of the lower side.

[Sixth embodiment]
In the sixth embodiment of the present invention, both the first inner wall surface and the second inner wall surface of the housing are provided with microchannels, which are grooves provided in the inner wall surface of the housing.
FIG. 7 is a cross-sectional view schematically showing an example in which microchannels are provided on both the first inner wall surface and the second inner wall surface of the housing. As in FIG. 2D, this figure shows the shape of the microchannel in the portion overlapping with the wick 30 (second porous body 42).

FIG. 7 shows an example in which microchannels 70a are provided on both the first inner wall surface 11a and the second inner wall surface 12a of the housing. The microchannel 70a is a microchannel having a semicircular cross section shown in FIG. 6A.
In FIG. 7, the cross-sectional shape of the microchannel provided on the first inner wall surface 11a and the shape of the microchannel provided on the second inner wall surface 12a are the same semicircular shape, but they may be different shapes. . Also, the number of microchannels is the same (five), but the number may be different. Furthermore, although the width and depth of the microchannel and the spacing between the microchannels are the same in FIG. 7, they may be different.

Each microchannel shown in the fifth and sixth embodiments is a groove formed by recessing the first sheet or the second sheet in the thickness direction. Methods for forming grooves in the first sheet or the second sheet include etching, pressing, machining, and the like, and the method is not particularly limited.

[Seventh Embodiment]
The seventh embodiment of the present invention differs from the first embodiment in that the capillary structure is not a groove provided on the inner wall surface of the housing.
The seventh embodiment exemplifies a form in which the capillary structure is not a groove provided on the inner wall surface of the housing.
FIG. 8A is a perspective view schematically showing an example in which a space sandwiched by additional parts is used as a capillary structure. FIG. 8B is a perspective view schematically showing an example in which a porous body has a capillary structure.

FIG. 8A shows a form in which a plurality of additional parts 81 of the housing are provided on the first inner wall surface 11 a of the first sheet 11 . A plurality of additional portions 81 extend toward the wick 30 (the first porous body 41 is shown in FIG. 8A). A predetermined space is provided between the adjacent additional portions 81 , and this space becomes the capillary structure 80 .
The capillary structure 80 has such a depth and width that it can function as a liquid channel through which the liquid-phase working medium 20 flows by capillary force.
The depth of the space is preferably 5 μm or more and 50 μm or less, and the width of the space is preferably 5 μm or more and 100 μm or less.

The additional portion 81 can be a portion in which the thickness of the first inner wall surface 11a of the first sheet 11 is increased by an additive method (pattern plating). Alternatively, it may be a portion that is locally increased in thickness by attaching some material to the first inner wall surface 11a of the first sheet 11 . The additional portion formed by the additive method is preferably made of the same material as the housing, and preferably the housing is made of copper and the additional portion is also made of copper.
If the additional portion 81 is too thick, the steam flow path will be divided, resulting in a decrease in heat uniformity. Therefore, the thickness of the additional portion 81 is preferably 30% or less of the thickness of the internal space.

FIG. 8B shows a mode in which a capillary structure 90 made of a porous material is provided on the first inner wall surface 11a of the first sheet 11. FIG. One end (second end) of the capillary structure 90 is in contact with the wick 30 (the first porous body 41 is shown in FIG. 8A).
The capillary structure 90 is made of a porous body, and the same materials as those of the first and second porous bodies that constitute the wick can be used.
If the capillary structure 90 is too thick, it cuts off the steam flow path, resulting in a decrease in heat uniformity. Therefore, the thickness of the capillary structure 90 is preferably 30% or less of the thickness of the internal space.
Also, the capillary structure 90 is not in contact with both the first inner wall surface and the second inner wall surface of the housing. Therefore, it is distinguished from the first porous body and the second porous body that constitute the wick.

Although FIG. 8B shows one plate-like member as the capillary structure 90, it may have a structure in which a plurality of rod-like members are arranged, and its shape is not particularly limited.
Also, the width of the capillary structure 90 is not limited.

Also, instead of the capillary structure 90 made of a porous material, a fiber bundle in which fibers are linearly bundled may be used as the capillary structure.

[Eighth embodiment]
In the eighth embodiment of the present invention, pillars are provided in the internal space of the housing for maintaining the shape of the housing. The position of the capillary structure when pillars are provided will be described.
FIG. 9A is a plan view schematically showing an example of a vapor chamber in which pillars are provided inside a housing.
FIG. 9B is a cross-sectional view taken along line DD of FIG. 9A.

In the vapor chamber 5 shown in FIG. 9A, many pillars 11b are provided inside the housing 10F. The pillars 11 b are columns provided at predetermined intervals on the first inner wall surface 11 a of the first sheet 11 and may be integrated with the first sheet 11 . For example, it may be formed by etching the first inner wall surface 11 a of the first sheet 11 .
By providing the pillars 11b, the gap between the first sheet 11 and the second sheet 12 can be maintained at the height of the pillars 11b or more, thereby preventing the internal space from becoming narrow (thin).

When pillars are provided in the internal space of the housing, the capillary structure is preferably provided on the inner wall surface on the side where the pillars are not provided.
FIG. 9B shows an example in which a capillary structure 70 is provided on the second inner wall surface 12a of the second sheet 12. As shown in FIG.

By providing the capillary structure on the inner wall surface of the sheet where the pillar is not provided, the formation of the capillary structure and the formation of the pillar can be performed separately, which is advantageous in terms of the process. Forming the capillary structure and the pillars on the same sheet complicates the process.

For example, when a pillar is formed by etching a copper foil having a thickness similar to that of the internal space to be formed, if the other portion is etched while not etching the portion that will become the pillar, the portion that was not etched can be removed. can form pillars in At this time, if another capillary structure is to be formed as a groove on the same copper foil, it is necessary to draw a separate groove pattern for the capillary structure so as not to interfere with the arrangement of the pillars.
Only the groove portion needs to be etched to a different depth than the etching for forming the pillars. Therefore, the process becomes complicated.

In the embodiment shown in FIG. 9A, pillars are provided on the inner wall surface of the first sheet, but unlike the above embodiment, pillars may be provided on the inner wall surface of the second sheet. In this case, the capillary structure is preferably provided on the inner wall surface of the first sheet.

[Ninth Embodiment]
The ninth embodiment of the present invention differs from the first embodiment in the form of the wick. Another example of a wick will be described.

In the first embodiment, the wick includes a first porous body and a second porous body, and in the wick, between the first porous body and the second porous body, the direction in which the first porous body and the second porous body extend Although the liquid-phase flow path is formed by providing a gap along the wick, the wick may have a form in which it does not have a liquid-phase flow path.
FIG. 10 is a plan view schematically showing an example of a vapor chamber in which the wick does not have a liquid phase flow path.
In vapor chamber 6 shown in FIG. 10, unlike vapor chamber 1 shown in FIG. 2A, wick 130 is a single porous body and does not include first porous body 41 and second porous body . Therefore, in the vapor chamber 6 , the liquid channel 51 is not formed, but the liquid channel is formed by one porous body forming the wick 130 .

Also, in each of the embodiments described so far, the example in which the wick is a porous body has been described, but the wick in each embodiment is not limited to a porous body. As the wick, in addition to the porous body, a fiber bundle obtained by linearly bundling fibers can be used.
A braided fiber bundle can be used as the fiber bundle.
As the fibers, for example, metal wires such as copper, aluminum, and stainless steel wires, and non-metal wires such as carbon fibers and glass fibers can be used. Among them, a metal wire is preferable because of its high thermal conductivity. For example, a fiber bundle can be obtained by bundling about 200 copper wires with a diameter of about 0.03 mm.

[Electronic Equipment Equipped with Heat Diffusion Device]
The heat diffusion device of the present invention can be mounted on electronic equipment for the purpose of heat dissipation. Therefore, it can be used as an electronic device comprising the heat diffusion device of the present invention and an electronic component attached to the outer wall surface of the housing constituting the heat diffusion device.
As described above, the heat diffusion device of the present invention operates independently without the need for external power, and utilizes the latent heat of vaporization and latent heat of condensation of the working medium to diffuse heat two-dimensionally and at high speed. Therefore, an electronic device equipped with the heat diffusion device of the present invention can effectively dissipate heat in a limited space inside the electronic device.
The electronic component corresponds to the heat source HS shown in FIG.

Examples of electronic devices include smartphones, tablet terminals, laptops, game machines, and wearable devices. Electronic parts that are objects to be cooled include, for example, heat-generating elements such as central processing units (CPUs), light-emitting diodes (LEDs), and power semiconductors.

In the electronic device, the electronic components are preferably attached to the outer wall surface located on the opposite side of the first inner wall surface of the housing. In this case, the housing has an evaporator on the first inner wall surface, and the electronic component is positioned in the evaporator when viewed from the thickness direction.

The electronic components may be attached directly to the outer wall surface of the housing, or may be attached via other members such as adhesives, sheets, and tapes with high thermal conductivity.

The heat diffusion device of the present invention can be used for a wide range of applications in fields such as personal digital assistants. For example, it can be used to lower the temperature of a heat source such as a CPU and extend the operating time of electronic equipment, and can be used in smartphones, tablet terminals, laptop computers, and the like.

1, 2A, 2B, 3, 4A, 4B, 4C, 4D, 4E, 5, 6 vapor chamber 10, 10A, 10B, 10C, 10D, 10E, 10F housing 11 first sheet 11a first inner wall surface 11b pillar 12 Second sheet 12a Second inner wall surface 13 Space 20 Working medium 30, 30a, 30b, 30c, 30d, 30e, 30f, 30g, 30h, 30i, 30j, 30k, 130 Wick 41 First porous body 42 Second porous body 50 Steam channel 51 Liquid phase channel 61, 61A, 61B, 61C, 61D, 61E, 61G, 61H, 61I, 61J First side 62, 62A, 62B, 62C, 62D, 62E, 62F, 62G, 62I, 62J 2 sides 70, 70a, 70b, 70c capillary structure (microchannel)
70A, 70B, 70C, 70D, 70E, 70F, 70G, 70H, 70I, 70J, 70K, 70L capillary structure 71 first end (first part)
71' first part 72 second end (second part)
72' Part 2 80 Capillary structure (space)
81 additional part 90 capillary structure (porous body)
HS Heat source EP Evaporator

Claims (11)

a housing having a first inner wall surface and a second inner wall surface facing each other in the thickness direction;
a working medium enclosed in the internal space of the housing;
a wick arranged in the internal space of the housing,
The wick has a portion along a direction perpendicular to the thickness direction and in contact with the first inner wall surface and the second inner wall surface of the housing,
A steam flow path is formed in the internal space of the housing,
The planar shape of the housing viewed from the thickness direction is a shape having a first side and a second side forming an internal angle of 180° or more,
The heat spreading device further comprising a capillary structure in the interior space of the housing, the capillary structure having a first portion adjacent to the first side or the second side and a second portion contacting the wick. The wick includes a first porous body and a second porous body,
In the wick, a gap is provided between the first porous body and the second porous body along the direction in which the first porous body and the second porous body extend, thereby forming a liquid phase flow path. The heat-spreading device of claim 1, wherein the heat-spreading device is The thermal diffusion device according to claim 1 or 2, wherein said first part of said capillary structure is in contact with said first side or said second side. The heat spreading device according to any one of claims 1 to 3, wherein said second part of said capillary structure is in contact with one said wick. The heat spreading device according to any one of claims 1 to 3, wherein said second part of said capillary structure is in contact with a plurality of said wicks. The heat diffusion device according to any one of claims 1 to 5, wherein the capillary structure is a groove provided in at least one of the first inner wall surface and the second inner wall surface of the housing. . The heat diffusion device according to claim 6, wherein the groove has a depth of 10 µm or more and 30 µm or less. The heat diffusion device according to claim 6 or 7, wherein the groove has a width of 30 µm or more and 100 µm or less. The thermal diffusion device according to any one of claims 6 to 8, wherein said capillary structure comprises a plurality of said grooves. The heat diffusion device according to any one of claims 1 to 9, wherein the housing has an evaporator that evaporates the working medium, and the end of the wick is located in the evaporator. The housing has an evaporating section that evaporates the working medium, the first side is located farther from the evaporating section than the second side, and the first section of the capillary structure extends from the first side. The heat spreading device according to any one of claims 1 to 10, adjacent to one side.

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