WO2022075175A1 - Electronic device and thermal diffusion device - Google Patents

Abstract

A thermal diffusion device (1) characterized by having: a first fluid flow path (50B) wherein the area of a fluid flow path (50) inside an evaporation unit is at least 15% of the area of the evaporation unit (EP), an end section of the fluid flow path (50), on the evaporation unit (EP) side, is positioned inside the evaporation unit (EP), and a flow path length (L1B) from a point (E1B) where the fluid flow path (50) reaches the evaporation unit (EP) to an end of the evaporation unit (EP) is at least 30% of the shortest distance (D1B) from a point (E1B) where the fluid flow path (50) reaches the evaporation unit (EP) to the center of gravity (C1) of the evaporation unit (EP); and a second fluid flow path (50A) wherein a flow path length (L1A) from a point (E1A) where the fluid flow path (50) reaches the evaporation unit (EP) to an end (T1A) of the evaporation unit (EP) is at least 10% and less than 30% of the shortest distance (D1A) from the point (E1A) where the fluid flow path (50) reaches the evaporation unit (EP) to the center of gravity (C1) of the evaporation unit (EP).

Description

Electronic devices and heat diffusion devices

The present invention relates to an electronic device and a heat diffusion device.

In recent years, the amount of heat generated has increased due to the high integration and high performance of devices. In addition, as the miniaturization of products progresses, the heat generation density increases, so heat dissipation measures are important. This situation is especially noticeable in the field of mobile terminals such as smartphones and tablets. As the heat countermeasure member, a graphite sheet or the like is often used, but since the heat transport amount is not sufficient, the use of various heat countermeasure members is being considered. Above all, the use of a vapor chamber, which is a planar heat pipe, is being studied as a heat diffusion device capable of diffusing heat very effectively.

The vapor chamber has a structure in which a working medium and a wick that transports the working medium by capillary force are enclosed inside the housing. The working medium absorbs heat from the heat generating element in the evaporation unit that absorbs heat from the heat generating element and evaporates in the vapor chamber, then moves in the vapor chamber, is cooled, and returns to the liquid phase. The working medium that has returned to the liquid phase moves to the evaporation part on the heat generating element side again by the capillary force of the wick, and cools the heat generating element. By repeating this, the vapor chamber operates independently without having external power, and can diffuse heat two-dimensionally at high speed by utilizing the latent heat of vaporization and the latent heat of condensation of the working medium.

The vapor chamber is also required to be thinner in order to support the thinner mobile terminals such as smartphones and tablets. In such a thin vapor chamber, it becomes difficult to secure mechanical strength and heat transfer efficiency.

Therefore, as described in Patent Document 1, in order to secure the mechanical strength of the housing constituting the vapor chamber, the wick arranged inside the housing is supported to maintain the shape of the housing. It has been proposed to be used as a body.

In the vapor chamber described in Patent Document 1, a pair of inner wall surfaces facing each other of the housing, a side surface of the wick that does not contact the pair of inner wall surfaces, and a facing surface formed with a gap from the side surface of the wick. It is characterized in that a liquid pool flow path of condensed working fluid is formed in the enclosed space. According to Patent Document 1, by combining the wick and the liquid pool flow path, it is possible to create a state in which the liquid is always supplied to the wick, so that the pressure loss of the liquid as a whole of the liquid flow path can be reduced, and the pressure loss of the liquid can be reduced. As a result, it is said that the maximum heat transport amount of the vapor chamber can be increased.

Japanese Unexamined Patent Publication No. 2019-11370

As described in Patent Document 1, when a liquid pool flow path is provided inside the wick, the liquid pool flow path becomes a liquid phase portion for moving the working medium of the liquid phase, so that the liquid phase It is possible to prevent the flow of the working medium from becoming stagnant. However, there is room for improvement from the viewpoint of increasing the circulation efficiency of not only the working medium of the liquid phase but also the working medium of the gas phase and increasing the heat transport efficiency of the vapor chamber.

The above problem is not limited to the vapor chamber, but is a problem common to heat diffusion devices capable of diffusing heat by the same configuration as the vapor chamber.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electronic device provided with a heat diffusion device having high heat transfer efficiency while ensuring the mechanical strength of a housing. .. It is also an object of the present invention to provide a heat diffusion device having high heat transfer efficiency while ensuring the mechanical strength of the housing.

The electronic device of the present invention is an electronic device including a heat diffusion device and a heat generating element, and the heat diffusion device includes a housing having a first inner wall surface and a second inner wall surface facing each other in the thickness direction. The housing includes a working medium enclosed in the internal space of the housing and a wick arranged in the internal space of the housing, and the housing has an evaporating part for evaporating the working medium. The heat generating element is arranged on the outer wall surface of the housing located in the evaporating portion, and the wick includes a plurality of capillary structures linearly extending from the evaporating portion, and at least a part thereof is surrounded by the capillary structure. The liquid flow path of the working medium is formed in the region and / or the inside of the capillary structure, and the total area of the liquid flow path in the evaporation portion is the total area of the liquid flow path in the plan view from the thickness direction. The liquid flow path has a first liquid flow path and a second liquid flow path, and is an end portion of the first liquid flow path on the evaporation part side and the first liquid flow path. 2 The ends of the liquid flow path on the evaporation portion side are all located in the evaporation portion, and the first liquid from the point where the first liquid flow path reaches the evaporation portion to the end on the evaporation portion side. The flow path length of the flow path is 30% or more of the shortest distance from the point where the first liquid flow path approaches the evaporation part to the center of gravity of the evaporation part, and the second liquid flow path is in the evaporation part. The flow path length of the second liquid flow path from the approaching point to the end on the evaporation section side is the shortest distance from the point where the second liquid flow path approaches the evaporation section to the center of gravity of the evaporation section. It is characterized by being 10% or more and less than 30%.

The heat diffusion device of the present invention has 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, and the internal space of the housing. A thermal diffusion device comprising a wick, wherein the housing has an evaporative section that evaporates the working medium, wherein the wick is a plurality of capillary structures linearly extending from the evaporative section. And / or having a liquid phase portion constituting the liquid flow path of the working medium inside the capillary structure and / or a region surrounded by the capillary structure at least in part thereof, and having a liquid phase portion constituting the liquid flow path of the working medium, in the thickness direction. The total area of the liquid flow path in the evaporative section is 15% or more of the area of the evaporative section, and the liquid flow path includes the first liquid flow path and the second liquid flow path. The end of the first liquid flow path on the evaporation part side and the end of the second liquid flow path on the evaporation part side are both located in the evaporation part, and the first liquid flow path evaporates. The flow path length of the first liquid flow path from the point approaching the portion to the end on the evaporation section side is the shortest from the point where the first liquid flow path approaches the evaporation section to the center of gravity of the evaporation section. The flow path length of the second liquid flow path from the point where the second liquid flow path reaches the evaporation part to the end on the evaporation part side is 30% or more of the distance, and the flow path length of the second liquid flow path is the second liquid flow path. Is 10% or more and less than 30% of the shortest distance from the point approaching the evaporative part to the center of gravity of the evaporative part.

According to the present invention, it is possible to provide an electronic device provided with a heat diffusion device having high heat transfer efficiency while ensuring the mechanical strength of the housing.

FIG. 1A is a perspective view schematically showing an example of an electronic device according to the first embodiment of the present invention. FIG. 1B is a perspective view schematically showing an example of a heat diffusion device with a heat generating element, which is a part of the configuration of the electronic device according to the first embodiment of the present invention. FIG. 2 is a sectional view taken along line II-II of the heat diffusion device constituting the heat diffusion device with the heat generating element shown in FIG. 1B. FIG. 3 is a sectional view taken along line III-III of the heat diffusion device constituting the heat diffusion device with the heat generating element shown in FIG. 1B. FIG. 4 is an enlarged view of the vicinity of the evaporation portion of the heat diffusion device shown in FIG. FIG. 5 is a partially enlarged cross-sectional view of the vicinity of the evaporation portion of an example of the heat diffusion device according to the second embodiment of the present invention. FIG. 6 is a partially enlarged cross-sectional view of the vicinity of the evaporation portion of an example of the heat diffusion device according to the third embodiment of the present invention. FIG. 7 is a partially enlarged cross-sectional view of the vicinity of the evaporation portion of an example of the heat diffusion device according to the fourth embodiment of the present invention. FIG. 8 is a partially enlarged cross-sectional view of the vicinity of the evaporation portion of an example of the heat diffusion device according to the fifth embodiment of the present invention. FIG. 9 is a cross-sectional view schematically showing an example of the heat diffusion device according to the sixth embodiment of the present invention. FIG. 10 is a cross-sectional view schematically showing an example of a heat diffusion device according to a seventh embodiment of the present invention. FIG. 11 is a cross-sectional view schematically showing an example of the heat diffusion device according to the eighth embodiment of the present invention. FIG. 12 is a cross-sectional view of the heat diffusion device according to the ninth embodiment of the present invention in a direction perpendicular to the direction in which the capillary structure extends. FIG. 13 is a cross-sectional view of the heat diffusion device according to the tenth embodiment of the present invention in a direction perpendicular to the direction in which the capillary structure extends. FIG. 14 is a cross-sectional view of the capillary structure in the heat diffusion device according to the tenth embodiment of the present invention in a direction perpendicular to the direction in which the capillary structure extends. FIG. 15 is a partially enlarged cross-sectional view of the heat diffusion device according to the tenth embodiment of the present invention in the vicinity of the evaporation portion.

Hereinafter, the electronic device and the heat diffusion device of the present invention will be described.
However, the present invention is not limited to the following configuration, 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 desirable configurations of the present invention described below is also the present invention.

It goes without saying that each embodiment shown below is an example, and partial replacement or combination of the configurations shown in different embodiments is possible. In the second and subsequent embodiments, the description of the matters common to the first embodiment will be omitted, and only the differences will be described. In particular, the same action and effect due to the same configuration will not be mentioned sequentially for each embodiment.

In the following description, unless each embodiment is particularly distinguished, it is simply referred to as "the electronic device of the present invention" or "the heat diffusion device of the present invention".

Hereinafter, as an embodiment of the electronic device of the present invention, a case where a vapor chamber is used as a heat diffusion device will be described as an example. In the electronic device of the present invention, a heat diffusion device such as a heat pipe may be used.
Further, as an embodiment of the heat diffusion device of the present invention, a vapor chamber will be described as an example. The heat diffusion device of the present invention can also be applied to a heat diffusion device such as a heat pipe.

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

[First Embodiment]
FIG. 1A is a perspective view schematically showing an example of an electronic device according to the first embodiment of the present invention.
The electronic device 100 shown in FIG. 1A includes a heat diffusion device 1 and an electronic component 110.
The electronic component 110 is attached to the outer wall surface of the housing 10 of the heat diffusion device 1.
The electronic component 110 may be directly attached to the outer wall surface of the housing 10, or may be attached via another member such as an adhesive, a sheet, or a tape having high thermal conductivity.

Examples of the electronic component 110 include heat generating elements such as a central processing unit (CPU), a light emitting diode (LED), and a power semiconductor.

Examples of the electronic device 100 include smartphones, tablet terminals, notebook computers, game devices, wearable devices, and the like.

In the electronic device of the present invention, the housing has an evaporation portion in the internal space, and the electronic component overlaps the evaporation portion in a plan view from the thickness direction.

In the electronic device 100, the electronic component 110 corresponds to the heat generating element HE shown in FIG. 1B, which will be described later. That is, in a plan view from the thickness direction Z, the electronic component 110 overlaps the evaporation portion EP of the housing 10.

As shown in FIG. 1A, it is preferable that the electronic device 100 further has a device housing 120.

FIG. 1B is a heat diffusion device with a heat generating element, which is a part of the configuration of the electronic device shown in FIG. 1A. The heat diffusion device shown in FIG. 1B is a heat diffusion device according to the first embodiment of the present invention.
The heat diffusion device with a heating element includes a heat diffusion device 1 and a heating element HE.
As the heat generating element HE, the above-mentioned electronic component 110 is used.

The heat diffusion device constituting the electronic device of the present invention is also the heat diffusion device of the present invention.
The heat diffusion device having the shape shown in FIG. 1 is also called a vapor chamber.

FIG. 2 is a sectional view taken along line II-II of the heat diffusion device constituting the heat diffusion device with the heat generating element shown in FIG. 1B. FIG. 3 is a sectional view taken along line III-III of the heat diffusion device constituting the heat diffusion device with the heat generating element shown in FIG. 1B.
As shown in FIG. 2, the heat diffusion device 1 includes a hollow housing 10 that is hermetically sealed. As shown in FIG. 3, 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. 2 and 3, the heat diffusion device 1 includes a wick 30 arranged in the internal space of the housing 10. Further, the working medium 20 is enclosed in the internal space of the housing 10. The wick refers to a structure having a capillary structure that transports a working medium by capillary force.

As shown in FIG. 2, the housing 10 is provided with an evaporation unit EP that evaporates the enclosed working medium. Further, the housing 10 may be set with a condensation portion CP for condensing the evaporated working medium 20.
In the internal space of the housing 10, the portion near the heat generating element HE and heated by the heat generating element HE corresponds to the evaporation part EP.
On the other hand, the portion away from the evaporation portion EP corresponds to the condensation portion CP.
Since the portion heated by the heat generating element HE corresponds to the evaporation part EP, the size of the evaporation part EP and the size of the heat generating element HE do not have to be completely the same. However, from the viewpoint of designing the heat transport efficiency and detecting the alignment between the heat generating element HE and the evaporating part EP, it is preferable that the size of the evaporating part EP and the size of the heat generating element HE are almost the same.
Further, the evaporated working medium 20 can be condensed other than the condensed portion CP. In the present embodiment, the portion where the evaporated working medium 20 is particularly easy to condense is also represented in FIG. 2 as a condensing portion CP.

The heat generating element HE is arranged on the outer wall surface of the housing 10. The heat generating element HE may be in direct contact with the outer wall surface of the housing 10, or may be in contact with the heat conductive grease, a metal plate such as a copper plate, or the like. The heat conductive grease or the metal plate can suppress a decrease in heat transport efficiency due to unevenness (gap) between the outer wall surface of the housing 10 and the surface of the heat generating element HE.
The outer wall surface of the housing 10 may be previously provided with a design such as an unevenness or a marker indicating a position where the heat generating element HE is arranged. Further, the outer wall surface of the housing 10 may be provided with a design such as an unevenness or a marker indicating the position of the evaporation portion EP.

In FIGS. 2 and 3, the wick 30 includes a plurality of capillary structures 31 linearly extending from the evaporation unit EP. The capillary structure 31 functions as a wick that transports the working medium 20 by the capillary force. The porous body 31 is composed of, for example, a porous body such as a metal porous body, a ceramic porous body, or a resin porous body. The porous body 31 may be composed of, for example, a sintered body such as a metal porous sintered body or a ceramic porous sintered body. The porous body 31 is preferably composed of a porous sintered body of copper or nickel.

The capillary structure 31 may be composed of a fiber bundle in which a plurality of fibers are linearly bundled instead of the porous body. In this case, the capillary structure 31 preferably contains a braided fiber bundle. In a crocheted fiber bundle in which a plurality of fibers are woven, unevenness is likely to be present on the surface, so that when the capillary structure contains the crocheted fiber bundle, the working medium of the liquid phase is easily transported to the evaporation part. ..

Examples of the fibers constituting the fiber bundle include metal wires such as copper, aluminum and stainless steel, and non-metal wires such as carbon fibers and glass fibers. Above all, the metal wire is preferable because it has a high thermal conductivity. For example, a fiber bundle can be obtained by bundling about 200 copper wires having a diameter of about 0.03 mm.

The following is an example of the case where the capillary structure is a porous body.
Inside the capillary structure 31, a liquid phase portion 51 is provided along the direction in which the capillary structure 31 extends. The liquid phase portion 51 is partitioned by a first capillary structure 31a and a second capillary structure 31b constituting the capillary structure 31, and a first inner wall surface 11a and a second inner wall surface 12a of the housing 10. Therefore, it can be said that the liquid phase portion 51 is a region in which at least a part thereof is surrounded by the capillary structure 31.
In the liquid phase section 51, the working medium of the liquid phase is transported toward the evaporation section EP. Further, the first capillary structure 31a and the second capillary structure 31b also have an action of transporting the working medium of the liquid phase. Therefore, the liquid phase portion 51 and the first capillary structure 31a and the second capillary structure 31b that partition the liquid phase portion 51 are collectively referred to as a liquid flow path 50. The liquid flow path 50 includes a region (liquid phase portion 51) partially surrounded by the first capillary structure 31a and the second capillary structure 31b, and the first capillary structure 31a and the second capillary structure 31b. It can be said that it is formed inside.
In one capillary structure 31, the distance a between the first capillary structure 31a and the second capillary structure 31b corresponds to the width of the liquid phase portion 51.
On the other hand, in the internal space of the housing 10, the portion that is not the liquid flow path 50 becomes the steam flow path 52. The distance b between the capillary structures 31 facing each other via the steam flow path 52 corresponds to the width of the steam flow path 52.
As shown in FIG. 3, the width a of the liquid phase portion 51 is shorter than the width b of the vapor flow path 52.

As shown in FIG. 2, the liquid flow path 50 may extend from the evaporation portion EP to the condensation portion CP. In the evaporation section EP, the liquid flow paths 50 extend radially, and each liquid flow path 50 is not connected to the end portion on the evaporation section EP side in the evaporation section EP. On the other hand, in the condensed portion CP, the ends of all the liquid flow paths 50 on the condensed portion CP side are connected to each other.
The liquid flow path 50 may extend in a different direction, or may be branched or merged, from the evaporation portion EP to the condensation portion CP.
The liquid flow path 50 and the steam flow path 52 adjacent to each other extend substantially in parallel. Further, the liquid flow path 50 and the steam flow path 52 are alternately arranged in a direction substantially perpendicular to the direction in which the liquid flow path 50 extends.

The heat diffusion device 1 is planar as a whole. That is, the housing 10 is planar as a whole. Here, the "plane" 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 in the thickness direction Z. It means a shape that is considerably larger than a dimension (hereinafter referred to as a thickness or a height), for example, a shape having a width and a length of 10 times or more, preferably 100 times or more the thickness.

The size of the heat diffusion device 1, that is, the size of the housing 10 is not particularly limited. The width and length of the heat diffusion device 1 can be appropriately set according to the application. The width and length of the heat diffusion device 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, respectively. The width and length of the heat diffusion device 1 may be the same or different.

It is preferable that the housing 10 is composed of the first sheet 11 and the second sheet 12 facing each other to which the outer edges are joined. The materials constituting the first sheet 11 and the second sheet 12 are not particularly limited as long as they have properties suitable for use as a heat diffusion device, for example, thermal conductivity, strength, flexibility, flexibility and the like. .. The material constituting the first sheet 11 and the second sheet 12 is preferably a metal, for example, copper, nickel, aluminum, magnesium, titanium, iron, or an alloy containing them as a main component, and particularly preferably copper. Is. The materials constituting the first sheet 11 and the second sheet 12 may be the same or different, but are preferably the same.

The first sheet 11 and the second sheet 12 are joined to each other at their outer edges. The joining method is not particularly limited, but for example, laser welding, resistance welding, diffusion welding, brazing, TIG welding (tungsten-inert gas welding), ultrasonic welding, or resin encapsulation can be used, and is preferable. Can use laser welding, resistance welding or low welding.

The thicknesses of the first sheet 11 and the second sheet 12 are not particularly limited, but are preferably 10 μm or more and 200 μm or less, more preferably 30 μm or more and 100 μm or less, and further preferably 40 μm or more and 60 μm or less, respectively. The thicknesses of the first sheet 11 and the second sheet 12 may be the same or different. Further, the thickness of each of the first sheet 11 and the second sheet 12 may be the same throughout, or a part thereof may be thin.

The shapes of the first sheet 11 and the second sheet 12 are not particularly limited. For example, in the example shown in FIG. 3, the first sheet 11 has a flat plate shape having a constant thickness, and the second sheet 12 has a shape in which the outer edge portion is thicker than the portion other than the outer edge portion.

The thickness of the entire heat diffusion device 1 is not particularly limited, but is preferably 50 μm or more and 500 μm or less.

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, and for example, water, alcohols, CFC substitutes, or the like can be used. For example, the working medium 20 is an aqueous compound, preferably water.

In this embodiment, the wick 30 supports the first inner wall surface 11a and the second inner wall surface 12a of the housing 10 from the inside. By arranging the wick 30 in the internal space of the housing 10, it is possible to absorb the impact from the outside of the housing 10 while ensuring the mechanical strength of the housing 10. Further, by using the wick 30 as the support of the housing 10, the weight of the heat diffusion device 1 can be reduced.

In the example shown in FIG. 3, the first capillary structure 31a and the second capillary structure 31b are in contact with the first inner wall surface 11a and the second inner wall surface 12a. The first capillary structure 31a and the second capillary structure 31b may be in contact with either the first inner wall surface 11a or the second inner wall surface 12a, and may be in contact with the first inner wall surface 11a and the second inner wall surface 12a. It doesn't have to be.

In the evaporation unit EP, the working medium 20 of the liquid phase located in the liquid phase unit 51 is heated and evaporated through the inner wall surface of the housing 10. As the working medium 20 evaporates, the pressure of the gas in the steam flow path 52 in the vicinity of the evaporation unit EP increases. As a result, the working medium 20 of the gas phase moves in the steam flow path 52 toward the condensed portion CP side.

The gas phase working medium 20 that has reached the condensing portion CP is deprived of heat through the inner wall surface of the housing 10 and is condensed into droplets. As described above, the working medium 20 of the liquid phase can be condensed other than the condensed portion CP. The droplets of the working medium 20 permeate into the pores of the capillary structure 31 by the capillary force. Further, a part of the working medium 20 of the liquid phase that has penetrated into the pores of the capillary structure 31 flows into the liquid phase portion 51.

The working medium 20 of the liquid phase that has flowed into the liquid flow path 50 moves to the evaporation section EP by the capillary force, and is heated and evaporated in the evaporation section EP.

The working medium 20 that has evaporated and becomes a gas phase moves to the condensed portion CP side again through the steam flow path 52. In this way, the heat diffusion device 1 can repeatedly use the gas-liquid phase change of the working medium 20 to repeatedly transport the heat recovered on the evaporation unit EP side to the condensation unit CP side.

In the heat diffusion device of the present invention, a part of the liquid flow path is approaching the evaporation part.
In a plan view from the thickness direction, the total area of the liquid flow path in the evaporation section is 15% or more of the area of the evaporation section EP.
By setting the total area of the liquid flow path in the evaporation section to 15% or more of the area of the evaporation section, a sufficient amount of the working medium of the liquid phase can be supplied into the evaporation section, so that dryout occurs. It can be suppressed.

In a plan view from the thickness direction, the total area of the liquid flow paths in the evaporation section is preferably 80% or less of the area of the evaporation section.
If the total area of the liquid flow path in the evaporation section exceeds 80% of the area of the evaporation section, it becomes difficult to secure a sufficient passage for the vapor flow path in the evaporation section. As a result, the gas-liquid exchange in the evaporation part is not sufficiently performed, and dryout is likely to occur.

The liquid flow path has a first liquid flow path and a second liquid flow path.
Both the first liquid flow path and the second liquid flow path are liquid flow paths whose ends on the evaporation portion side are located in the evaporation portion.
The first liquid flow path and the second liquid flow path can be distinguished by the ratio of the flow path length in the evaporation section EP to the shortest distance from the point where the liquid flow path approaches the evaporation section to the center of gravity of the evaporation section.
Of the liquid flow paths approaching the evaporation section, the flow path length from the point where the liquid flow path reaches the evaporation section to the end of the evaporation section is from the point where the liquid flow path reaches the evaporation section to the center of gravity of the evaporation section. The case where it is 30% or more of the shortest distance is the first liquid flow path. Further, the flow path length from the point where the liquid flow path reaches the evaporation part to the end of the evaporation part is 10% or more and 30% of the shortest distance from the point where the liquid flow path reaches the evaporation part to the center of gravity of the evaporation part. When it is less than, it is the second liquid flow path.
The first liquid flow path and the second liquid flow path will be described with reference to FIG.

FIG. 4 is an enlarged view of the vicinity of the evaporation portion of the heat diffusion device shown in FIG.
As shown in FIG. 4, the liquid flow paths 50A, 50B, 50C, 50D, 50E, 50F, 50G, and 50H are present in the evaporation unit EP. In each of the liquid flow paths 50A, 50B, 50C, 50D, 50E, 50F, 50G, and 50H, the end portion on the evaporation unit EP side is located in the evaporation unit EP.

The length of the flow path in the evaporation section EP of the liquid flow path 50A is the end T1A of the liquid phase section 51 at the end of the liquid flow path 50A on the evaporation section EP side from the point E1A where the liquid flow path 50A approaches the evaporation section EP. Is the length up to (the length indicated by the double arrow L1A in FIG. 4). The shortest distance from the point E1A where the liquid flow path 50A approaches the evaporation section EP to the center of gravity C1 of the evaporation section EP is the distance indicated by the double _- headed arrow D1A. The length L1A / distance D1A is about 20%. Therefore, the liquid flow path 50A is the second liquid flow path. The point where the liquid flow path reaches the evaporation part is a point where the line indicating the center in the width direction of the liquid flow path and the boundary line of the evaporation part intersect.

The shape of the liquid flow path 50C in the evaporation section EP is axisymmetric with the liquid flow path 50A with respect to _a line segment extending in the direction along the length direction Y through the center of gravity C1 of the evaporation section EP. .. Further, the shapes of the liquid flow path 50G and the liquid flow path 50E in the evaporation section EP pass through the center of gravity C1 of the evaporation section EP and are liquid flow paths for the line segments extending in the width direction X, _respectively . It is line-symmetrical with 50A and the liquid flow path 50C.
Therefore, with respect to the liquid flow paths 50C, 50E, 50G, the flow path length in the evaporation section EP and the shortest distance from the points E1C, E1E, E1G where _each liquid flow path reaches the evaporation section EP to the center of gravity C1 of the evaporation section EP. Are the same as the liquid flow path 50A. Therefore, the liquid flow paths 50C, 50E, and 50G are all second liquid flow paths.

The length of the flow path in the evaporation section EP of the liquid flow path 50B is the end T1B of the liquid phase section 51 at the end of the liquid flow path 50B on the evaporation section EP side from the point E1B where the liquid flow path 50B approaches the evaporation section EP. (Length indicated by double arrow L1B in FIG. 4). Further, the shortest distance from the point E1B where the liquid flow path 50B approaches the evaporation unit EP to the center of gravity C1 of the evaporation unit EP is the distance indicated by the double _- headed arrow D1B. The length L1B / distance D1B is about 75%. Therefore, the liquid flow path 50B is the first liquid flow path.

The shape of the liquid flow path 50F in the evaporation section EP is axisymmetric with the liquid flow path 50B with respect to _a line segment extending in the direction along the width direction X through the center of gravity C1 of the evaporation section EP. Therefore, regarding the liquid flow path 50F, the flow path length in the evaporation section EP and the shortest distance from the _point E1F where the liquid flow path 50F approaches the evaporation section EP to the center of gravity C1 of the evaporation section EP are the same as those of the liquid flow path 50B. Is. Therefore, the liquid flow path 50F is the first liquid flow path.

The length of the flow path in the evaporation section EP of the liquid flow path 50D is the end T1D of the liquid phase section 51 at the end of the liquid flow path 50D on the evaporation section EP side from the point E1D where the liquid flow path 50D approaches the evaporation section EP. Is the length up to (the length indicated by the double arrow L1D in FIG. 4). Further, the shortest distance from the point _E1D where the liquid flow path 50D approaches the evaporation section EP to the center of gravity C1 of the evaporation section EP is the length indicated by the double-headed arrow D1D. The length L1D / distance D1D is about 28%. Therefore, the liquid flow path 50D is the second liquid flow path.

The shape of the liquid flow path _50H in the evaporation section EP is axisymmetric with the liquid flow path 50D with respect to a line segment extending in the direction along the length direction Y through the center of gravity C1 of the evaporation section EP. .. Therefore, regarding the liquid flow path 50H, the flow path length in the evaporation section EP and the shortest distance from the point _E1H where the liquid flow path 50H approaches the evaporation section EP to the center of gravity C1 of the evaporation section EP are the same as those of the liquid flow path 50D. Is. Therefore, the liquid flow path 50H is the second liquid flow path.

From the above, in the evaporation section EP shown in FIG. 4, two first liquid flow paths (liquid flow path 50B, liquid flow path 50F) and six second liquid flow paths ( liquid flow paths 50A, 50C, 50D, 50E, 50G, 50H) exist. The total area of the liquid flow path in the evaporation section EP is 46.6% of the area of the evaporation section EP.

In the heat dissipation device according to the first embodiment of the present invention, since the end portion of the liquid flow path on the evaporation portion side is located in the evaporation portion, the working medium of the liquid phase is directly refluxed into the evaporation portion to dry out. The occurrence can be suppressed. Further, it has both a first liquid flow path and a second liquid flow path as the liquid flow path, and the area of the liquid flow path in the evaporation section is 15 of the area of the evaporation section in a plan view from the thickness direction. % Or more. In such a state, the circulation of the working medium of the gas phase and the circulation of the working medium of the liquid phase are well-balanced, and high heat transfer efficiency can be exhibited.
When the liquid flow path does not have the second liquid flow path, the steam flow path in the evaporation portion is likely to be blocked by the first liquid flow path, and the circulation efficiency of the working medium of the gas phase is not sufficient.
When the liquid flow path does not have the first liquid flow path, the liquid working medium cannot be refluxed to the vicinity of the center of the evaporation portion, so that the circulation efficiency of the working medium of the liquid phase is not sufficient.
When the area of the liquid flow path in the evaporating part is less than 15% of the area of the evaporating part in a plan view from the thickness direction, sufficient heating cannot be performed on the working medium of the liquid phase, and the liquid cannot be sufficiently heated. The circulation efficiency of the working medium of the phase becomes insufficient.

In the heat dissipation device of the present invention, it is preferable that the end portion of the second liquid flow path on the evaporation portion side is not connected to the first liquid flow path.
If the end of the second liquid flow path on the evaporation part side is connected to the first liquid flow path, the steam passage is blocked in the steam part and the working medium is prevented from moving from the evaporation part to the condensing part. ..

The minimum width of the steam flow path in the evaporation part is preferably 500 μm or more. When the minimum width of the steam flow path in the evaporation portion is within the above range, the working medium of the gas phase easily passes through the working medium of the gas phase, and the circulation efficiency of the working medium of the gas phase is improved.

The number of the first liquid flow paths included in the liquid flow paths is not particularly limited, and may be one or a plurality.
The number of the first liquid flow paths included in the liquid flow paths is preferably 6 or less, and more preferably 4 or less.

The number of the second liquid flow paths included in the liquid flow path is not particularly limited, and may be one or a plurality, but a plurality of lines is preferable.
When the liquid flow path has a plurality of second liquid flow paths, the circulation efficiency of the working medium of the liquid phase can be improved without increasing the ratio of the liquid flow paths in the evaporation portion so much.
The number of the second liquid flow paths included in the liquid flow paths is preferably 6 or less, and more preferably 4 or less.

Subsequently, an electronic device and a heat diffusion device according to another embodiment of the present invention will be described. However, in the electronic device according to the other embodiment of the present invention, the configuration other than the heat diffusion device is the same as the electronic device according to the first embodiment of the present invention. Therefore, the heat diffusion device according to another embodiment of the present invention will be described below.

[Second Embodiment]

In the heat diffusion device according to the second embodiment of the present invention, the liquid flow path has a plurality of first liquid flow paths. Further, the ends of the plurality of first liquid flow paths on the evaporation portion side are connected to each other by the center of gravity of the evaporation portion, and the first liquid flow paths communicate with each other.

FIG. 5 is a partially enlarged cross-sectional view of the vicinity of the evaporation portion of an example of the heat diffusion device according to the second embodiment of the present invention. The heat diffusion device shown in FIG. 5 is also a modified example in which the shapes of the liquid flow paths 50B, 50D, 50F, and 50H are deformed from the heat diffusion device shown in FIG.
As shown in FIG. 5, liquid flow paths 50A, 50B', 50C, 50D', 50E, 50F', 50G, 50H'are present in the evaporation unit EP. In each of the liquid flow paths 50A, 50B', 50C, 50D', 50E, 50F', 50G, and 50H', the end portion on the evaporation portion EP side is located in the evaporation portion EP.
In each of the liquid flow paths 50B', 50D', 50F', and 50H', the end of the liquid flow path on the evaporation portion EP _side reaches the center of gravity C1 of the evaporation portion EP. Further, in the liquid flow paths 50B', 50D', 50F', and 50H', the liquid flow paths communicate with each other. That is, each end T1B', T1D', T1F', T1H'of the liquid phase portion at the end of the liquid flow path 50B', 50D', 50F', 50H'on the evaporation portion EP side is the center of gravity C of the evaporation portion EP. It overlaps with ₁ .

The length of the flow path in the evaporation section EP of the liquid flow path 50B'is the liquid phase section at the end of the liquid flow path 50B'on the evaporation section EP side from the point E1B'where the liquid flow path 50B'appears to the evaporation section EP. The length up to the end T1B'of 51 (the length indicated by the double arrow L1B' in FIG. 5). Further, the shortest distance from the point _E1B'where the liquid flow path 50B'appears to the evaporation part EP to the center of gravity C1 of the evaporation part EP is the distance indicated by the double-headed arrow D1B'. In the liquid flow path 50B', since the end T1B'of the liquid phase portion 51 at the end on the EP side of the evaporation portion overlaps with the center of gravity C1 of the evaporation portion EP, the length _L1B'and the distance D1B' are equal and the length. The L1B'/ distance D1B' is 100%. Therefore, the liquid flow path 50B'is the first liquid flow path.
Regarding the liquid flow paths 50D', 50F', and 50H'where the points approaching the evaporation part EP are the points E1D', E1F', and E1H', respectively, the end T1D'of the liquid phase part 51 at the end on the evaporation part EP side. , T1F'and _T1H ' overlap with the center of gravity C1 of the evaporation part EP. Therefore, the liquid flow paths 50D', 50F', and 50H'are also the first liquid flow paths like the liquid flow path 50B'.

The liquid flow paths 50A, 50C, 50E, and 50G are the same as the heat diffusion device shown in FIG. Therefore, the liquid flow paths 50A, 50C, 50E, and 50G are all second liquid flow paths.

From the above, in the evaporation section EP shown in FIG. 5, four first liquid flow paths (liquid flow paths 50B', 50D', 50F', 50H') and four second liquid flow paths (liquid flow) Roads 50A, 50C, 50E, 50G) exist. The total area of the liquid flow path in the evaporation section EP is 55.7% of the area of the evaporation section EP.

In the present specification, with respect to the liquid flow paths having n points approaching the evaporation part, it is considered that the n liquid flow paths are connected to each other at predetermined positions. The procedure for dividing the liquid flow path is as follows. By dividing the liquid flow path, the number of liquid flow paths arranged in the evaporation section and the end portion of each liquid flow path on the evaporation section side are determined.
(1) Of the liquid flow path, the position closest to the center of gravity of the evaporation part is set as the reference point.
(2) Divide the liquid flow path with reference to the specified reference point.

Procedure (1)
First, among the liquid flow paths having n points approaching the evaporation part, the point closest to the center of gravity of the evaporation part is set as a reference point.
When there are two or more points on the liquid flow path closest to the center of gravity of the evaporation unit, a point having a large number of liquid flow paths divided by the reference point is selected. On the other hand, when the number of liquid flow paths divided by the reference point is the same, for each liquid flow path, the liquid flow path with respect to the distance from the point where the liquid flow path reaches the evaporation part to the center of gravity of the evaporation part. Find the ratio of the distance from the point where the liquid reaches the evaporation part to the end of the liquid phase part at the end of the liquid flow path on the evaporation part side, and select the point where the total value of this ratio is the highest.

Procedure (2)
Subsequently, the liquid flow path is divided by a defined reference point.
The number of liquid channels to be divided varies depending on the position of the reference point and the shape of the liquid channel. For example, when the reference point is located on the linear liquid flow path, the liquid flow path is divided into two by the reference point. When the reference point is located on the branch point of the Y-shaped liquid flow path, the liquid flow path is divided into three by the reference point.

The above procedure will be described by applying it to the heat diffusion device shown in FIG.
The heat diffusion device shown in FIG. 5 has a cross-shaped liquid flow path in the evaporation unit EP. This cross-shaped liquid flow path has four points (points E1B', E1D', E1F', E1H') approaching the evaporation part EP in the evaporation part EP. In this cross-shaped liquid flow path, the point closest to the center of gravity C ₁ of the evaporation section EP is the center of gravity C ₁ of the evaporation section EP. Therefore, the center of gravity C1 of the evaporation portion serves as a reference point for dividing the liquid flow path [procedure ( ₁ )].
The cross-shaped liquid flow path is divided into four liquid flow paths (liquid flow paths 50B', 50D', 50F', 50H') with the center of gravity C ₁ of the evaporation portion EP defined in this way as a reference point. [Procedure (2)].
As a result, in the cross-shaped liquid flow path shown in FIG. 5, the liquid phase portion 51 at the end of the four liquid flow paths (liquid flow paths 50B', 50D', 50F', 50H') on the EP side of the evaporation part. It is considered that the ends of the above (T1B', T1D', T1F', _T1H ', respectively) are connected and communicate with each other at the center of gravity C1 of the evaporation unit EP.

Each liquid flow path divided by the above procedure (2) may have two or more points where the liquid flow path approaches the evaporation portion. In this case, the liquid flow path is further divided by the following procedure (3) and procedure (4).

Procedure (3)
When each liquid flow path divided by the procedure (2) has two or more points where the liquid flow path approaches the evaporation portion, the liquid flow path is divided so that the flow path length becomes the longest.
Specifically, the length (flow path length) along the liquid flow path from each point where the liquid flow path reaches the evaporation part to the reference point is compared, and the liquid flow path having the longest flow path length is the parent. It is a flow path (primary flow path). The remaining liquid flow path is a child flow path (secondary flow path) that branches from the parent flow path at the branch point from the parent flow path. In the child flow path, it is considered that the end portion of the liquid flow path on the evaporation portion side is connected to the parent flow path at the branch point from the parent flow path.

Procedure (4)
The operation of step (3) is repeated until the liquid flow path cannot be divided.
For example, when the child flow path remaining in the procedure (3) has two points approaching the evaporation portion, the child flow path is divided from the child flow path by the following procedure.
The liquid flow path having the longest flow path length is referred to as a child flow path (secondary flow path). The remaining liquid flow path is a grandchild flow path (tertiary flow path) that branches from the child flow path at the branch point from the child flow path. It is considered that the end of the liquid flow path on the evaporation portion side of the grandchild flow path is connected to the child flow path at the branch point from the child flow path.

In the above procedures (1) and (2), the liquid is a liquid flow path that passes through the reference point in the evaporation section, and when the reference point is regarded as one end, the other end is located in the evaporation section. The flow path is not considered.
Such a liquid flow path is regarded as the upstream portion of the liquid flow path having the longest flow path length in the evaporation section among the liquid flow paths divided in the procedures (1) and (2). Further, when there are two or more such liquid flow paths, the flow path length of the upstream portion and the flow path length (downstream portion of the downstream portion) in the evaporation portion of the liquid flow path divided by the procedures (1) and (2). The combination in which the total of the flow path lengths) is the longest.

[Third Embodiment]
In the heat diffusion device according to the third embodiment of the present invention, the liquid flow path further has a third liquid flow path.
The third liquid flow path is a liquid flow path in which the end portion of the liquid flow path on the evaporation portion side is located outside the evaporation portion.

FIG. 6 is a partially enlarged cross-sectional view of the vicinity of the evaporation portion of an example of the heat diffusion device according to the third embodiment of the present invention. Further, FIG. 6 is also a modified example in which the shape of the liquid flow path 50B of the heat diffusion device shown in FIG. 4 is changed.
As shown in FIG. 6, the liquid flow path 50B'' does not reach the evaporation section EP. That is, the end of the liquid flow path 50B'' on the EP side of the evaporation portion is located outside the evaporation portion.
Of the liquid flow paths, the liquid flow path 50B'' whose end on the EP side of the evaporation portion is located outside the evaporation portion is the third liquid flow path.

Based on the above, the evaporation section EP shown in FIG. 6 has one first liquid flow path (liquid flow path 50F) and six second liquid flow paths ( liquid flow paths 50A, 50C, 50D, 50E, 50G). , 50H) exists. The total area of the liquid flow path in the evaporation section EP is 36.4% of the area of the evaporation section EP.

Depending on the shape of the housing and the shape and position of the evaporation part, if the first liquid flow path or the second liquid flow path is arranged for the purpose of increasing the circulation efficiency of the working medium of the liquid phase, the steam flow path will be blocked. , The circulation efficiency of the working medium of the gas phase in the evaporation part may be lowered. On the other hand, since the third liquid flow path is a liquid flow path that does not reach the evaporation part, the circulation efficiency of the working medium of the liquid phase in the evaporation part is improved without lowering the circulation efficiency of the working medium of the gas phase. Can be enhanced.

[Fourth Embodiment]
The heat diffusion device according to the fourth embodiment of the present invention further has a fourth liquid flow path in the evaporation unit. The fourth liquid flow path is a liquid flow path in which the flow path length in the evaporation section exceeds 0% of the shortest distance from the point where the liquid flow path approaches the evaporation section to the center of gravity of the evaporation section and becomes less than 10%. ..

FIG. 7 is a partially enlarged cross-sectional view of the vicinity of the evaporation portion of an example of the heat diffusion device according to the fourth embodiment of the present invention. Further, FIG. 7 is also a modified example in which the shape of the liquid flow path 50B of the heat diffusion device shown in FIG. 4 is changed.

As shown in FIG. 7, the liquid flow path 50B'''is approaching the evaporation portion EP. The length of the flow path in the evaporation section EP of the liquid flow path 50'''' is the evaporation section EP of the liquid flow path 50B'''' from the point E1B'''' where the liquid flow path 50B'''' approaches the evaporation section EP. It is the length to the end T1B'''' of the liquid phase portion 51 at the side end portion (the length indicated by the double arrow L1B'' in FIG. 7). Further, the shortest distance from the _point E1B'''' where the liquid flow path 50B'''' reaches the evaporation section EP to the center of gravity C1 of the evaporation section EP is D1B''''. The length L1B'''/ distance D1B'''' is about 9%. Therefore, the liquid flow path 50B'''' is the fourth liquid flow path.

Based on the above, the evaporation section EP shown in FIG. 7 has one first liquid flow path (liquid flow path 50F) and six second liquid flow paths ( liquid flow paths 50A, 50C, 50D, 50E, 50G). , 50H) and one fourth liquid flow path (liquid flow path 50B'''). The total area of the liquid flow path in the evaporation section EP is 37.5% of the area of the evaporation section EP.

Depending on the shape of the housing and the shape and position of the evaporating part, even if the positions and numbers of the first liquid flow path and the second liquid flow path arranged in the evaporating part are adjusted, the circulation of the liquid working medium in the evaporating part is performed. It may not be possible to balance efficiency with the circulation efficiency of the working medium of the gas. Even in such a case, if the fourth liquid flow path is used, it becomes easy to adjust the balance between the circulation efficiency of the liquid working medium and the circulation efficiency of the gas working medium.

[Fifth Embodiment]
FIG. 8 is a partially enlarged cross-sectional view of the vicinity of the evaporation portion of an example of the heat diffusion device according to the fifth embodiment of the present invention.
As shown in FIG. 8, liquid flow paths 50I, 50J, 50K, 50L, 50M, and 50N exist in the evaporation unit EP.

The length of the flow path in the evaporation section EP of the liquid flow path 50I is the end T2I of the liquid phase section 51 at the end of the liquid flow path 50I on the evaporation section EP side from the point E2I where the liquid flow path 50I approaches the evaporation section EP. (Length indicated by double arrow L2I in FIG. 8). Further, the shortest distance from the point E2I where the liquid flow path 50I approaches the evaporation part EP to the center of gravity _C2 of the evaporation part EP is the distance indicated by the double-headed arrow D2I. The length L2I / distance D2I is about 29%. Therefore, the liquid flow path 50I is the second liquid flow path.

The shape of the liquid flow path 50K in the evaporation section EP is axisymmetric with the liquid flow path 50I with respect to a line segment extending in the direction along the length direction Y through the center of gravity _C2 of the evaporation section EP. .. Therefore, with respect to the liquid flow path 50K, the flow path length in the evaporation section EP and the shortest distance from the point where the liquid flow path 50K approaches the evaporation section EP to the center of gravity _C2 of the evaporation section are the same as those of the liquid flow path 50I. .. Therefore, the liquid flow path 50K is the second liquid flow path.

The length of the flow path in the evaporation section EP of the liquid flow path 50J is the end T2J of the liquid phase section 51 at the end of the liquid flow path 50J on the evaporation section EP side from the point E2J where the liquid flow path 50J approaches the evaporation section EP. (Length indicated by double arrow L2J in FIG. 8). The shortest distance from the point E2J where the liquid flow path 50J approaches the evaporation section EP to the center of gravity _C2 of the evaporation section EP is the distance indicated by the double-headed arrow D2J. Here, the length L2J / D2J is about 9%. Therefore, the liquid flow path 50J is the fourth liquid flow path.

The length of the flow path in the evaporation section EP of the liquid flow path 50L is the end T2L of the liquid phase section 51 at the end of the liquid flow path 50L on the evaporation section EP side from the point E2L where the liquid flow path 50L approaches the evaporation section EP. Is the length up to L2L (in FIG. 8, the sum of the length indicated by the double arrow L2L1 and the length indicated by the double arrow L2L2). Further, the shortest distance from the point E2L where the liquid flow path 50L approaches the evaporation unit EP to the center of gravity _C2 of the evaporation unit EP is the distance indicated by the double-headed arrow D2L. Here, the length L2L / distance D2L is about 110%. Therefore, the liquid flow path 50L is the first liquid flow path.

The shape of the liquid flow path 50N in the evaporation section EP is axisymmetric with the liquid flow path 50L with respect to a line segment extending in the direction along the length direction Y through the center of gravity _C2 of the evaporation section EP. .. Therefore, regarding the liquid flow path 50N, the flow path length in the evaporation section EP and the shortest distance from the point where the liquid flow path 50N approaches the evaporation section to the center of gravity _C2 of the evaporation section are the same as those of the liquid flow path 50L. Therefore, the liquid flow path 50N is the first liquid flow path.

The length of the flow path in the evaporation section EP of the liquid flow path 50M is the end T2M of the liquid phase section 51 at the end of the liquid flow path 50M on the evaporation section EP side from the point E2M where the liquid flow path 50M approaches the evaporation section EP. Is the length up to (the length indicated by the double arrow L2M in FIG. 8). Further, the shortest distance from the point E2M where the liquid flow path 50M approaches the evaporation unit EP to the center of gravity _C2 of the evaporation unit EP is the length indicated by the double-headed arrow D2M. The length L2M / distance D2M is about 29%. Therefore, the liquid flow path 50M is the second liquid flow path.

From the above, the evaporation section EP shown in FIG. 8 includes two first liquid flow paths ( liquid flow paths 50L, 50N) and three second liquid flow paths ( liquid flow paths 50I, 50K, 50M). There is one fourth liquid flow path (liquid flow path 50J).
The total area of the liquid flow path in the evaporation section EP is 53.3% of the area of the evaporation section EP.

As described above, in the heat diffusion device of the present invention, the flow path length in the evaporation section of the first liquid flow path is 100% of the shortest distance from the point where the liquid flow path approaches the evaporation section to the center of gravity of the evaporation section. It may be exceeded.

[Sixth Embodiment]
FIG. 9 is a cross-sectional view schematically showing an example of the heat diffusion device according to the sixth embodiment of the present invention.

In the heat diffusion device 1A shown in FIG. 9, unlike the heat diffusion device 1 shown in FIG. 2, the ends of the liquid phase portion 51 on the CP side of the condensed portion are not connected to each other.

That is, in the heat diffusion device of the present invention, the ends of the liquid phase portion on the condensed portion side do not have to be connected to each other. Further, the end portion of the liquid phase portion on the condensed portion side may not be closed by the capillary structure.

[7th Embodiment]
In the seventh embodiment of the present invention, the housing has a plurality of evaporation parts.

FIG. 10 is a cross-sectional view schematically showing an example of a heat diffusion device according to a seventh embodiment of the present invention.

In the heat diffusion device 1B shown in FIG. 10, a plurality of evaporation units EP ₁ and EP ₂ and a condensation unit CP are set in the housing 10. The number, arrangement, and size of the evaporated parts are not particularly limited.
In at least one of the evaporation section EP ₁ and the evaporation section EP ₂ , the total area of the liquid flow paths in the evaporation section is 15% or more of the area of the evaporation section, and the evaporation section is the first liquid flow path. It suffices to have a second liquid flow path. In the heat diffusion device 1B, the evaporation unit EP ₁ satisfies the above conditions.

That is, in the heat diffusion device of the present invention, the housing may include a plurality of evaporation units.

[Eighth Embodiment]
In the eighth embodiment of the present invention, the planar shape of the housing is different from that of the first to seventh embodiments, and the vapor flow path and the liquid flow path are formed along the planar shape of the housing.

FIG. 11 is a cross-sectional view schematically showing an example of a heat diffusion device according to an eighth embodiment of the present invention.

In the heat diffusion device 1C shown in FIG. 11, the planar shape of the housing 10A is L-shaped. The liquid flow path 50 extending from the evaporation unit EP to the condensation unit CP has a liquid flow path 501 extending along the length direction Y and a liquid flow path 502 extending along the width direction X.

The liquid flow path 501 and the liquid flow path 502 are connected at a substantially right angle, but the connection direction between the liquid flow path 501 and the liquid flow path 502 is not limited to the above direction. For example, the liquid flow path 501 and the liquid flow path 502 may be connected at an angle other than 90 °, or may be connected by a curved line.

In the heat diffusion device of the present invention, the planar shape of the housing is not particularly limited, and examples thereof include polygons such as triangles and rectangles, circles, ellipses, and combinations thereof. Further, the planar shape of the housing may be L-shaped, C-shaped (U-shaped), or the like. Further, a through hole may be provided inside the housing. The planar shape of the housing may be a shape corresponding to the application of the heat diffusion device, the shape of the place where the heat diffusion device is incorporated, and other components existing in the vicinity.

[9th Embodiment]
In the ninth embodiment of the present invention, a liquid flow path is formed in a region surrounded by a capillary structure, a support, and a first inner wall surface of a housing, and inside the capillary structure.

FIG. 12 is a cross-sectional view of the heat diffusion device according to the ninth embodiment of the present invention in a direction perpendicular to the direction in which the capillary structure extends.
As shown in FIG. 12, the heat diffusion device 2 has a housing 10 having a first inner wall surface 11a and a second inner wall surface 12a facing in the thickness direction Z, and a wick 30 arranged in the internal space of the housing 10. And prepare. The wick 30 includes a capillary structure 131.

In the internal space of the housing 10, the capillary structure 131, the first inner wall surface 11a and the second inner wall surface 12a are supported from the inside via the capillary structure 131, and the support 140a extending in parallel with the capillary structure 131a. And the support 140b are arranged. The support 140a and the support 140b face each other with a predetermined distance apart. The distance between the support 140a and the support 140b corresponds to the width of the liquid phase portion 151.

The region surrounded by the capillary structure 131, the support 140a and the support 140b, and the first inner wall portion 11a is the liquid phase portion 151. The capillary structure 131 and the liquid phase portion 151 are collectively referred to as a liquid flow path 150.
It is preferable that the width of the liquid phase portion 151 and the configuration of the liquid flow path 150 are the same as those of the first embodiment of the present invention.

The support 140a and the support 140b may be any material as long as they can support the first inner wall surface 11a and the second inner wall surface 12a of the housing 10 from the inside, and the material thereof is not particularly limited.
Examples of the material constituting the support 140a and the support 140b include resins, metals, ceramics, mixtures thereof, and laminates. Further, the support may be integrated with the housing, and may be formed by, for example, etching the inner wall surface of the first sheet or the second sheet.
Further, the support 140a and the support 140b may be composed of a capillary structure.

In the heat diffusion device of the present invention, in the heat diffusion device shown in FIG. 12, the capillary structure 131 may be arranged on the surface of the second inner wall surface 12a instead of the first inner wall surface 11a, or the capillary structure 131 may be arranged in the first inner wall surface. In addition to the wall surface 11a, a capillary structure may be further arranged on the surface of the second inner wall surface 12a, and the support 140a and / or the support 140b may be composed of the capillary structure.

[10th Embodiment]
In the tenth embodiment of the present invention, the capillary structure is composed of a fiber bundle in which a plurality of fibers are bundled linearly.
A capillary structure composed of a fiber bundle in which a plurality of fibers are linearly bundled has a capillary structure similar to a porous body, and can transport an operating medium. Since the capillary structure composed of fiber bundles has a high ability to transport the working medium along the direction in which the fiber bundles extend, it is preferable to arrange the fibers constituting the fiber bundles along the direction in which the working medium is desired to be transported. ..

FIG. 13 is a cross-sectional view of the heat diffusion device according to the tenth embodiment of the present invention in a direction perpendicular to the direction in which the capillary structure extends.
As shown in FIG. 13, the heat diffusion device 3 is arranged in the housing 10 having the first inner wall surface 11a and the second inner wall surface 12a facing the thickness direction Z, and the first inner space of the housing 10. A wick 30 that supports the inner wall surface 11a and the second inner wall surface 12a from the inside is provided.

A liquid flow path composed of fiber bundles will be described with reference to FIG.
FIG. 14 is a cross-sectional view of an example of a capillary structure in the heat diffusion device according to the tenth embodiment of the present invention in a direction perpendicular to the direction in which the capillary structure extends.
As shown in FIG. 14, the wick 30 has a fiber bundle 231 in which a plurality of fibers 235 are bundled. There is a gap between the plurality of fibers 231. The gap is a space in which the working medium of the liquid phase can move due to the action of capillary force, that is, the liquid phase portion 251. The liquid phase portion 251 exists inside the fiber bundle 231 which is a capillary structure. Therefore, it can be said that the entire fiber bundle 231 including the gap between the fibers is the liquid flow path 250.

FIG. 15 is a partially enlarged cross-sectional view of the heat diffusion device according to the tenth embodiment of the present invention in the vicinity of the evaporation portion.
As shown in FIG. 15, liquid flow paths 250A, 250B, 250C, 250D, 250E, 250F, 250G, 250H exist in the evaporation unit EP.
In each of the liquid flow paths 250A, 250B, 250C, 250D, 250E, 250F, 250G, and 250H, the end portion on the evaporation portion EP side is located in the evaporation portion EP.

The length of the flow path in the evaporation section EP of the liquid flow path 250A is from the point E1A where the liquid flow path 250A approaches the evaporation section EP to the end T3A of the liquid phase section at the end of the liquid flow path 250A on the evaporation section EP side. (The length indicated by the double arrow L3A in FIG. 15).

Here, the position of the end T3A of the liquid phase portion at the end portion of the liquid flow path 250A on the evaporation portion EP side is the liquid phase portion at the end portion of the liquid flow path 50A on the evaporation portion EP side in the heat diffusion device shown in FIG. It is the same as the position of the terminal T1A of. That is, the length L3A in FIG. 15 is equal to the length L1A in FIG. Further, the position and size of the evaporation portion EP in FIG. 15 are also the same as those in FIG. Therefore, the length L3A / distance D3A is about 20% like the length L1A / distance D1A in FIG. Therefore, the liquid flow path 250A is the second liquid flow path.

The ratio of the flow path length from the point where the liquid flow path reaches the evaporation part to the end on the evaporation part side with respect to the shortest distance from the point where the liquid flow path reaches the evaporation part to the center of gravity of the evaporation part is shown in FIG. The same applies to the other liquid flow paths (250B to 250H) as in FIG. That is, similarly to the heat diffusion device shown in FIG. 4, the liquid flow paths 250A, 250C, 250D, 250E, 250G, 250H are the second liquid flow paths, and the liquid flow paths 250B and 250F are the first liquid flow paths. ..

Since the length of the capillary structure in the evaporation section EP is shortened, the total area of the liquid flow paths in the evaporation section EP is smaller than that of the heat diffusion device 1 shown in FIG. The total area of the liquid flow path in the evaporation section EP is 36.0% of the area of the evaporation section EP.

[Other embodiments]
In the heat diffusion device of the present invention, the capillary structure may have a constant width in the thickness direction, and may not have a constant width in the thickness direction. Further, the width of the end portion on the first inner wall surface side and the width of the end portion on the second inner wall surface side of the capillary structure may be the same or different.
The width of the capillary structure may be continuously narrowed from the end portion on the first inner wall surface side to the end portion on the second inner wall surface side.
The width of the capillary structure may be gradually narrowed from the end portion on the first inner wall surface side to the end portion on the second inner wall surface side.
The ends of the capillary structure constituting the liquid phase portion on the first inner wall surface side may be connected to each other. When the ends of the capillary structure are connected to each other, the contact area between the capillary structure and the first inner wall surface increases, which increases the adhesive strength and thus improves resistance to mechanical stress such as bending or vibration. Can be made to.
The capillary structure is a portion between the end portion on the first inner wall surface side and the end portion on the second inner wall surface side, which is wider than the end portion on the first inner wall surface side and the end portion on the second inner wall surface side. May have.
The capillary structure is a portion narrower than the end portion on the first inner wall surface side and the end portion on the second inner wall surface side between the end portion on the first inner wall surface side and the end portion on the second inner wall surface side. May have.

In the heat diffusion device of the present invention, in addition to the capillary structure, the wick has a first wick arranged along the first inner wall surface and / or a second wick arranged along the second inner wall surface. You may be doing it.
The first wick and the second wick are not particularly limited as long as they have a capillary structure in which the working medium can be moved by a capillary force. The wick's capillary structure may be a known structure used in conventional thermal diffusion devices. Examples of the capillary structure include microstructures having irregularities such as pores, grooves, and protrusions, such as a porous structure, a fiber structure, a groove structure, and a mesh structure.

The materials of the first wick and the second wick are not particularly limited, and for example, a metal porous film formed by etching or metal processing, a mesh, a non-woven fabric, a sintered body, a porous body, or the like is used. The mesh used as the material of the wick may be composed of, for example, a metal mesh, a resin mesh, or a surface-coated mesh thereof, and is preferably composed of a copper mesh, a stainless (SUS) mesh, or a polyester mesh. .. The sintered body used as the material of the wick may be composed of, for example, a metal porous sintered body and a ceramic porous sintered body, and is preferably composed of a copper or nickel porous sintered body. .. The porous body used as the material of the wick may be, for example, a porous body made of a metal porous body, a ceramic porous body, a resin porous body, or the like.

The size and shape of the first wick and the second wick are not particularly limited, but for example, it is preferable to have a size and shape that can be continuously installed from the evaporation part to the condensation part inside the housing.

The thicknesses of the first wick and the second wick are not particularly limited, but are, for example, 2 μm or more and 200 μm or less, preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 40 μm or less, respectively. The thickness of the first wick and the second wick may be partially different. The thickness of the first wick may be the same as or different from the thickness of the second wick.

The heat diffusion device of the present invention may be further provided with a plurality of columns arranged in the steam flow path and supporting the first inner wall surface and the second inner wall surface of the housing from the inside.

The material forming the column is not particularly limited, and examples thereof include resin, metal, ceramics, a mixture thereof, and a laminate. Further, the support column may be integrated with the housing, and may be formed by, for example, etching the inner wall surface of the first sheet or the second sheet.

The shape of the strut is not particularly limited as long as it can support the housing, but examples of the shape of the cross section perpendicular to the height direction of the strut include polygons such as rectangles, circles, and ellipses.

The height of the columns is not particularly limited, and may be the same as or different from the height of the capillary structure.

The height of the columns may be the same or different in one heat diffusion device. For example, the height of the stanchions in one area may be different from the height of the stanchions in another area.

The width of the strut is not particularly limited as long as it gives strength that can suppress the deformation of the housing of the heat diffusion device, but the equivalent circle diameter of the cross section perpendicular to the height direction of the end of the strut is, for example, 100 μm or more and 2000 μm. It is less than or equal to, preferably 300 μm or more and 1000 μm or less. By increasing the diameter equivalent to the circle of the support column, it is possible to further suppress the deformation of the housing of the heat diffusion device. On the other hand, by reducing the diameter equivalent to the circle of the column, it is possible to secure a wider space for the steam of the working medium to move.

The arrangement of the columns is not particularly limited, but is preferably arranged evenly in a predetermined area, more preferably evenly over the entire area, for example, so that the distance between the columns is constant. By arranging the columns evenly, uniform strength can be ensured throughout the heat diffusion device.

The heat diffusion device of the present invention can be mounted on an electronic device for the purpose of heat dissipation. Therefore, the electronic device provided with the heat diffusion device of the present invention is the electronic device of the present invention. Examples of the electronic device of the present invention include smartphones, tablet terminals, notebook computers, game devices, wearable devices and the like. As described above, the heat diffusion device of the present invention operates independently without the need for external power, and can diffuse heat in two dimensions at high speed by utilizing the latent heat of vaporization and the latent heat of condensation of the working medium. Therefore, in the electronic device of the present invention provided with the heat dissipation device or the heat diffusion device of the present invention, heat dissipation can be effectively realized in the limited space inside the electronic device.

The electronic device or heat diffusion device of the present invention can be used for a wide range of applications in the field of portable information terminals and the like. For example, it can be used to lower the temperature of a heat source such as a CPU and extend the usage time of an electronic device, and can be used for smartphones, tablets, notebook PCs, and the like.

1,1A, 1B, 1C, 2,3 heat diffusion device (vapor chamber)
10 Housing 11 1st sheet 12 2nd sheet 20 Working medium 30 Wick 31, 131 Capillary structure (porous)
31a First capillary structure (porous)
31b Second capillary structure (porous)
231 Capillary structure (fiber bundle)
235 Fiber 50, 150, 250, 501, 502 Liquid flow path 50B, 50B', 50D', 50F, 50F', 50H', 50L, 50N, 250B, 250F First liquid flow path 50A, 50C, 50D, 50E, 50G, 50H, 50I, 50K, 50M, 250A, 250C, 250D, 250E, 250G, 250H 2nd liquid flow path 50B `` 3rd liquid flow path 50B'''', 50J 4th liquid flow path 51, 151, 251 Liquid phase part 52 Steam flow path 100 Electronic equipment 110 Electronic parts (heating element)
120 Equipment housing 140a, 140b Support a Width of liquid phase part b Width of steam flow path C ₁ , C ₂ Center of gravity of evaporation part CP Condensing part D1A, D1B, D1B', D1B''', D1D, D2I, D2J , D2L, D2M The shortest distance from the point where the liquid flow path reaches the evaporation part to the center of gravity of the evaporation part E1A, E1B, E1B', E1B''', E1C, E1D, E1D', E1E, E1F, E1F', E1G , E1H, E1H', E2I, E2J, E2L, E2M Point where the liquid flow path reaches the inside of the evaporation part EP, EP ₁ , EP2 Evaporation part HE heating element L1A, _L3A , L1B, L1B', L1B''', L3B , L1D, L2I, L2J, L2L, L2M, L3D Flow path lengths in the evaporation part of the liquid flow path T1A, T1B, T1B', T1B''', T1D, T1D', T1F', T1H', T2I, T2J, T2L , T2M, T3A, T3B, T3D The end of the liquid phase part at the end of the liquid flow path on the evaporation part side X Width direction Y Length direction Z Thickness direction

Claims (10)

1. An electronic device including a heat diffusion device and a heat generating element.
   The heat diffusion device is arranged in a housing having a first inner wall surface and a second inner wall surface facing each other in the thickness direction, an actuating medium enclosed in the internal space of the housing, and the internal space of the housing. With a wick that will be
   The housing has an evaporation unit that evaporates the working medium.
   The heat generating element is arranged on the outer wall surface of the housing located at the evaporation portion.
   The wick comprises a plurality of capillary structures linearly extending from the evaporation section.
   A liquid flow path of the working medium is formed in a region partially surrounded by the capillary structure and / or inside the capillary structure.
   In a plan view from the thickness direction, the total area of the liquid flow path in the evaporation section is 15% or more of the area of the evaporation section.
   The liquid flow path has a first liquid flow path and a second liquid flow path, and has a first liquid flow path and a second liquid flow path.
   The end portion of the first liquid flow path on the evaporation portion side and the end portion of the second liquid flow path on the evaporation portion side are both located in the evaporation portion.
   The flow path length of the first liquid flow path from the point where the first liquid flow path reaches the evaporation part to the end on the evaporation part side is the point where the first liquid flow path approaches the evaporation part. It is 30% or more of the shortest distance from the evaporating part to the center of gravity of the evaporation part.
   The flow path length of the second liquid flow path from the point where the second liquid flow path reaches the evaporation part to the end on the evaporation part side is the point where the second liquid flow path approaches the evaporation part. An electronic device characterized in that it is 10% or more and less than 30% of the shortest distance from the evaporating part to the center of gravity of the evaporation part.
2. The liquid flow path has a plurality of the first liquid flow paths.
   The electronic device according to claim 1, wherein the ends of the first liquid flow path on the evaporation portion side are connected to each other by the center of gravity of the evaporation portion, and the first liquid flow paths communicate with each other.
3. The liquid flow path further has a third liquid flow path.
   The electronic device according to claim 1 or 2, wherein the end portion of the third liquid flow path on the evaporation portion side is located outside the evaporation portion.
4. The electronic device according to any one of claims 1 to 3, wherein the end portion of the second liquid flow path on the evaporation portion side is not connected to the first liquid flow path.
5. The electronic device according to any one of claims 1 to 4, wherein the total area of the liquid flow path in the evaporation section is 80% or less of the area of the evaporation section in a plan view from the thickness direction.
6. A housing having a first inner wall surface and a second inner wall surface facing each other in the thickness direction, an actuating medium enclosed in the internal space of the housing, and a wick arranged in the internal space of the housing. It is a heat diffusion device equipped with
   The housing has an evaporation unit that evaporates the working medium.
   The wick comprises a plurality of capillary structures linearly extending from the evaporation section.
   A liquid flow path of the working medium is formed in a region partially surrounded by the capillary structure and / or inside the capillary structure.
   In a plan view from the thickness direction, the total area of the liquid flow path in the evaporation section is 15% or more of the area of the evaporation section.
   The liquid flow path has a first liquid flow path and a second liquid flow path, and has a first liquid flow path and a second liquid flow path.
   The end portion of the first liquid flow path on the evaporation portion side and the end portion of the second liquid flow path on the evaporation portion side are both located in the evaporation portion.
   The flow path length of the first liquid flow path from the point where the first liquid flow path reaches the evaporation part to the end on the evaporation part side is the point where the first liquid flow path approaches the evaporation part. It is 30% or more of the shortest distance from the evaporating part to the center of gravity of the evaporation part.
   The flow path length of the second liquid flow path from the point where the second liquid flow path reaches the evaporation part to the end on the evaporation part side is the point where the second liquid flow path approaches the evaporation part. A heat diffusion device, characterized in that the shortest distance from the evaporation unit to the center of gravity is 10% or more and less than 30%.
7. The liquid flow path has a plurality of the first liquid flow paths.
   The heat diffusion device according to claim 6, wherein the ends of the first liquid flow path on the evaporation portion side are connected to each other by the center of gravity of the evaporation portion, and the first liquid flow paths communicate with each other.
8. The liquid flow path further has a third liquid flow path.
   The heat diffusion device according to claim 6 or 7, wherein the end portion of the third liquid flow path on the evaporation portion side is located outside the evaporation portion.
9. The heat diffusion device according to any one of claims 6 to 8, wherein the end portion of the second liquid flow path on the evaporation portion side is not connected to the first liquid flow path.
10. The heat diffusion device according to any one of claims 6 to 9, wherein the total area of the liquid flow paths in the evaporation section is 80% or less of the area of the evaporation section in a plan view from the thickness direction. ..
    
    
    

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