JP7283641B2 - heat spreading device - Google Patents

Description

The present invention relates to heat spreading devices.

In recent years, the amount of heat generated has been increasing due to the high integration and high performance of devices. In addition, as products become smaller, heat generation density increases, so heat dissipation measures are becoming 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 a 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 Document 1 discloses a flat container in which a working fluid is enclosed, and a wick provided inside the container. and a linear bundle in which fibers thicker than the fibers are linearly bundled, and the linear bundle is arranged in a cavity surrounded by the inner peripheral surface of the braided body, and is arranged around the braided body. discloses a heat pipe characterized in that a vapor channel for the working fluid is formed, and a liquid channel for the working fluid is formed in the cavity.

Japanese Patent Application Laid-Open No. 2018-76989 (Patent No. 6694799)

In the heat pipe described in Patent Document 1, by changing the thickness of the fiber used as the material of the wick, the wick is formed with an inner region and an outer region, and the inner region is a liquid flow path and the outer region is a vapor flow. road.

However, Patent Document 1 does not disclose or suggest how to effectively arrange the wick with respect to the heat source.

The above problem is not limited to the vapor chamber, but is common to any heat diffusion device capable of diffusing heat with the same configuration as the vapor chamber.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat diffusion device that secures a circulation path for a working medium and facilitates gas-liquid exchange. Another object of the present invention is to provide an electronic device comprising the above heat diffusion device.

A heat diffusion device of the present invention includes 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 an internal space of the housing, and the first wall surface of the housing. at least one wick positioned between the inner wall surface and the second inner wall surface. The wick extends from the first end to the second end in plan view from the thickness direction of the first inner wall surface. The wick is composed of a fiber bundle in which fibers are linearly bundled. When viewed in cross-section along the direction in which the wick extends and the thickness direction, the first end of the wick is located in the first region of the housing, and the first end and the second end of the wick are located in the first region of the housing. A part except for the end is located in a second area different from the first area of the housing. The wick has a first portion in contact with the first inner wall surface but not in contact with the second inner wall surface in the first region, and has the first inner wall surface and the second inner wall surface in the second region. has a second portion in contact with the

An electronic device of the present invention includes the heat diffusion device of the present invention.

ADVANTAGE OF THE INVENTION According to this invention, the circulation path of a working medium is ensured, and the thermal diffusion device with which gas-liquid is easy to be exchanged can be provided.

FIG. 1 is a perspective view schematically showing an example of the vapor chamber according to the first embodiment of the invention. FIG. 2 is a cross-sectional view of the vapor chamber shown in FIG. 1 along line II-II. FIG. 3 is a cross-sectional view of the vapor chamber shown in FIG. 2 along line III-III. FIG. 4 is an enlarged view of the portion indicated by IV in FIG. FIG. 5 is an enlarged view of the portion indicated by V in FIG. FIG. 6 is a cross-sectional view of the wick shown in FIG. 5 along line VI--VI. 7 is an enlarged view of the vicinity of the evaporator shown in FIG. 2. FIG. FIG. 8 is an enlarged view of the portion indicated by VIII in FIG. 9 is a cross-sectional view of the wick shown in FIG. 8 along line IX-IX. FIG. 10 is a plan view schematically showing an example of the vapor chamber according to the second embodiment of the invention. FIG. 11 is a plan view schematically showing another example of the vapor chamber according to the second embodiment of the invention. FIG. 12 is a plan view schematically showing an example of the vapor chamber according to the third embodiment of the invention. FIG. 13 is a plan view schematically showing an example of the vapor chamber according to the fourth embodiment of the invention.

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

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".

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.

The drawings shown below are schematic, and their dimensions, aspect ratios, etc. may differ from actual products.

[First embodiment]
FIG. 1 is a perspective view schematically showing an example of the vapor chamber according to the first embodiment of the invention. FIG. 2 is a cross-sectional view of the vapor chamber shown in FIG. 1 along line II-II. FIG. 3 is a cross-sectional view of the vapor chamber shown in FIG. 2 along line III-III.

The vapor chamber 1 shown in FIG. 1 comprises a hollow housing 10 that is hermetically sealed. 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 FIG. As shown in FIGS. 2 and 3, the vapor chamber 1 further includes a working medium 20 enclosed in the internal space of the housing 10 and a space between the first inner wall surface 11a and the second inner wall surface 12a of the housing 10. a plurality of wicks 30 arranged in the . In this embodiment, the plurality of wicks 30 includes six wicks 31, 32, 33, 34, 35 and 36, for example.

As shown in FIG. 2, the housing 10 is provided with an evaporation portion EP for evaporating the enclosed working medium 20 . The housing 10 may further include a condensation portion CP for condensing the evaporated working medium 20 . 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). 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. On the other hand, the part away from the evaporating part EP corresponds to the condensing part CP. Also, the evaporated working medium 20 can be condensed in places other than the condensing part CP. In the present embodiment, a portion where the evaporated working medium 20 is particularly likely to condense is expressed as a condensation portion CP.

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 Shapes that are considerably large relative to their dimensions (hereinafter referred to as thickness or height), for example shapes 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 vapor chamber 1 may be the same or different.

The housing 10 preferably consists of a first sheet 11 and a second sheet 12 facing each other with their outer edges joined together. 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. 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. The method of such bonding is not particularly limited, but for example, laser welding, resistance welding, diffusion bonding, brazing, TIG welding (tungsten-inert gas welding), ultrasonic bonding or resin sealing can be used, which is preferable. can use laser welding, resistance welding or brazing.

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 thickness 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, in the example shown in FIG. 3, the first sheet 11 has a flat plate shape with a constant thickness, and the second sheet 12 has 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 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, and the like can be used. For example, the working medium is an aqueous compound, preferably water.

As shown in FIG. 2, wicks 31, 32, 33, 34, 35, and 36, which are examples of the plurality of wicks 30, are arranged in parallel with each other in plan view from the thickness direction Z of the first inner wall surface 11a. , from the first end E1 to the second end E2. In the example shown in FIGS. 2 and 3, six wicks are included as the plurality of wicks 30, but the number of wicks 30 is not particularly limited as long as it is two or more.

In the example shown in FIG. 3, a wick 30, such as wick 31, is in contact with the first inner wall surface 11a and the second inner wall surface 12a. These wicks 30 may be in contact with either one of the first inner wall surface 11a and the second inner wall surface 12a, and may not be in contact with the first inner wall surface 11a and the second inner wall surface 12a.

FIG. 4 is an enlarged view of the portion indicated by IV in FIG.
As shown in FIG. 4, the wick 30 such as the wick 31 is composed of a fiber bundle in which fibers F are linearly bundled. These fiber bundles act as wicks that transport the working medium 20 by capillary force. Therefore, the working medium 20 evaporated in the evaporator EP and, for example, condensed in the condenser CP can be recirculated to the evaporator EP.

As the fibers F, 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.

Wick 30 such as wick 31 is preferably fixed to one or both of first inner wall surface 11 a and second inner wall surface 12 a of housing 10 . For example, when the fiber F is a metal wire, the wick 30 such as the wick 31 is preferably joined to either one or both of the first inner wall surface 11a and the second inner wall surface 12a of the housing 10 . The bonding method is not particularly limited, but spot welding, diffusion bonding, and the like can be used, for example.

As shown in FIG. 4, the cross section of the fiber F perpendicular to the direction in which the wick 30 such as the wick 31 extends preferably has a flat shape.
By flattening the cross section of the fibers F, even if the wick 30 is thin, the gaps between the fibers F are secured without the fibers F being closely packed, so that the liquid flow paths can be sufficiently secured. Furthermore, when the cross section of the fiber F is flat, the contact area with the housing 10 increases, thereby increasing the bonding strength, so that the structure is strong against external stress such as bending. As a result, it is possible to obtain a vapor chamber that is excellent in liquid circulation, liquid transportation capability, and reliability against external stress.

When the cross section of the fiber F perpendicular to the direction in which the wick 30 extends is flat, the aspect ratio (a/b) defined by the ratio of the major axis a to the minor axis b of the fiber F in the cross section is 1.1. It is preferably 2 or less, preferably 2 or less.

In FIG. 2, the wicks 31, 32, 33, 34, 35 and 36 each extend to the wall surface of the housing 10 located below the evaporator EP. As shown in FIG. 2, the wicks 30 such as the wick 31 are preferably arranged so as to be concentrated in the lower portion of the evaporator EP. By gathering the wick 30 in the lower part of the evaporating part EP, the working medium 20 can be circulated in a short distance from the evaporating part EP to the condensing part CP, for example.

On the other hand, it is preferable that the first steam flow path 51 is formed between adjacent wicks 30 . In this case, the outermost wick 30 (the wick 31 in FIGS. 2 and 3) of the plurality of wicks 30 and the housing 10 have a width wider than the first steam flow path 51 . It is preferable that the second steam flow path 52 is formed. Furthermore, a third steam channel 53 wider than the first steam channel 51 is formed between the other outermost wick 30 (the wick 36 in FIGS. 2 and 3) and the housing 10. It is preferable that Furthermore, the formation area of the second steam flow path 52 and the third steam flow path 53 is preferably 60% or more of the formation area of the entire steam flow path.

If the wick 30 such as the wick 31 is unevenly distributed in one part, the vapor of the working medium 20 does not pass through that part, so the uniform heating performance of the entire vapor chamber is lowered. Therefore, by providing a gap between the wicks 30 and using the gap as a steam flow path, the uniform heating performance can be improved. As a result, it is possible to obtain a vapor chamber which is excellent in liquid circulation and vapor circulation, and which has high liquid transport capacity and heat soaking performance.

The width of the first vapor channel 51 is preferably 300 μm or more and 3000 μm or less, and more preferably 1000 μm or more and 2000 μm or less. In addition, in the cross section shown in FIG. 3 , when the width of the first steam flow path 51 differs in the thickness direction Z, the width of the widest portion is defined as the width of the first steam flow path 51 .

When the second steam flow path 52 is formed, the width of the second steam flow path 52 is larger than the width of the first steam flow path 51 . The width of the second steam flow path 52 is preferably 5 mm or more, more preferably 10 mm or more. In addition, in the cross section shown in FIG. 3 , when the width of the second steam flow path 52 differs in the thickness direction Z, the width of the widest portion is defined as the width of the second steam flow path 52 .

When the third steam flow path 53 is formed, the width of the third steam flow path 53 is larger than the width of the first steam flow path 51 . The width of the third steam flow path 53 is preferably 5 mm or more, more preferably 10 mm or more. In addition, in the cross section shown in FIG. 3 , when the width of the third steam flow path 53 differs in the thickness direction Z, the width of the widest portion is defined as the width of the second steam flow path 52 . The width of the third steam channel 53 may be the same as or different from the width of the second steam channel 52 .

FIG. 5 is an enlarged view of the portion indicated by V in FIG. FIG. 6 is a cross-sectional view of the wick shown in FIG. 5 along line VI--VI.

As shown in FIG. 6 , when viewing a cross section along the direction in which the wick 30 such as the wick 31 extends and along the thickness direction Z, the first end E1 of the wick 30 such as the wick 31 is located in the first region of the housing 10 . A portion of the wick 30 excluding the first end E1 and the second end E2 located in R1 is located in a second region R2 of the housing 10 different from the first region R1. The wick 30, such as the wick 31, has a first portion P1 in contact with the first inner wall surface 11a and not in contact with the second inner wall surface 12a in the first region R1, and a first portion P1 in contact with the first inner wall surface 11a and not in contact with the second inner wall surface 12a in the second region R2. It has a second portion P2 in contact with the second inner wall surface 12a.

At least one of the plurality of wicks 30 should have the first portion P1, but it is preferable that all the wicks 30 have the first portion P1.

The first region R1 is preferably located in the evaporator EP. In a wick 30, such as wick 31, the first portion P1 is thinner than the second portion P2. The thinned first portion P1 widens the area of the portion where the vapor of the working medium 20 evaporates, so that a circulation path can be secured.

A wick 30, such as wick 31, may have a first portion P1 somewhere in first region R1, but first portion P1 of wick 30 may be located at the first portion of wick 30, as shown in FIG. It preferably includes edge E1.

As shown in FIG. 5, the first portion P1 of the wick 30 such as the wick 31 is preferably thicker than the second portion P2 of the wick 30 when viewed from the thickness direction Z of the first inner wall surface 11a. By making the first portion P1 thicker than the second portion P2 of the wick 30, the evaporation area is widened, so that gas-liquid exchange is smooth. In addition, in all the wicks 30, the first portion P1 may be thicker than the second portion P2, or the wick 30 having the first portion P1 thicker than the second portion P2 and the first portion P1 thicker than the second portion P2. may be mixed with a wick 30 that is not thick.

As shown in FIG. 5, among adjacent wicks 30, the first portion P1 of one wick 30 and the first portion P1 of the other wick 30 may be connected. Since the first portions P1 connected to each other complement the circulation of the liquid and the thinned first portions P1 maintain the vapor circulation path, gas-liquid exchange is smooth.

Alternatively, although not illustrated, the first portion P1 of one wick 30 and the first portion P1 of the other wick 30 among adjacent wicks 30 may be separated. In this case, the working medium 20 evaporated in the evaporation part EP can circulate through the gaps between the wicks 30 to, for example, the condensation part CP.

The wick 30 in which the adjacent first portions P1 are connected to each other and the wick 30 in which the adjacent first portions P1 are separated from each other may be mixed.

7 is an enlarged view of the vicinity of the evaporator shown in FIG. 2. FIG.
As shown in FIG. 7, in a plan view from the thickness direction Z of the first inner wall surface 11a, among the plurality of wicks 30, a wick 30 (for example, a wick 31) that is far from the center is located inside the wick 30. It is preferably longer than the wicks 30 (e.g., wicks 32 and 33) located at the end and projecting first end E1. By changing the length of the wick 30 and the position of the first end E1 according to the arrangement of the wick 30, the path of the working medium 20 evaporated in the evaporator EP can be secured.

FIG. 8 is an enlarged view of the portion indicated by VIII in FIG. 9 is a cross-sectional view of the wick shown in FIG. 8 along line IX-IX.

As shown in FIG. 9 , when viewing a cross section along the direction in which the wick 30 such as the wick 31 extends and the thickness direction Z, the second end E2 of the wick 30 such as the wick 31 is located in the first region of the housing 10 . It is located in a third region R3 different from R1 (see FIG. 6) and second region R2. The wick 30 such as the wick 31 preferably has a third portion P3 in the third region R3 that contacts the first inner wall surface 11a and does not contact the second inner wall surface 12a. Alternatively, although not shown, the wick 30 such as the wick 31 may have a third portion P3 that contacts the second inner wall surface 12a and does not contact the first inner wall surface 11a in the third region R3. Note that the wick 30 such as the wick 31 may not have the third portion P3 in the third region R3.

At least one wick 30 among the plurality of wicks 30 should have the third portion P3, but it is preferable that all the wicks 30 have the third portion P3.

The third region R3 is preferably located in the condensation section CP. In a wick 30, such as wick 31, the third portion P3 is thinner than the second portion P2. The thinned third portion P3 increases the exposed surface of the fibers between the first inner wall surface 11a and the second inner wall surface 12a, so that the condensed working medium 20 can be easily collected.

A wick 30, such as wick 31, may have a third portion P3 somewhere in the third region R3, but the third portion P3 of the wick 30 may be located at the second portion of the wick 30, as shown in FIG. It preferably includes edge E2.

As shown in FIG. 8, the third portion P3 of the wick 30 such as the wick 31 is preferably thicker than the second portion P2 of the wick 30 when viewed from the thickness direction Z of the first inner wall surface 11a. By making the third portion P3 of the wick 30 thicker than the second portion P2, the contact area with the inner wall surface of the housing 10 is increased, so that the condensed working medium 20 can be easily collected.

As shown in FIG. 8, of adjacent wicks 30, the third portion P3 of one wick 30 and the third portion P3 of the other wick 30 may be connected. Alternatively, although not illustrated, the third portion P3 of one wick 30 and the third portion P3 of the other wick 30 among the adjacent wicks 30 may be separated.

The width of each of the wicks 30 such as the wick 31 is preferably 500 μm or more and 5000 μm or less in the second portion P2. The widths of the wicks 30 in the second portions P2 may be the same or different. The width of the wick 30 may be constant in the thickness direction Z, or may not be constant. Moreover, the wick 30 having a constant width in the thickness direction Z and the wick 30 having a non-uniform width in the thickness direction Z may be mixed.

The height of each of the wicks 30 such as the wick 31 is preferably 20 μm or more and 300 μm or less, more preferably 50 μm or more and 200 μm or less, in the second portion P2. The height of the wick 30 in the second portion P2 may be the same or different.

[Second embodiment]
In the second embodiment of the present invention, the planar shape of the housing viewed from the thickness direction is different from that in the first embodiment.

FIG. 10 is a plan view schematically showing an example of the vapor chamber according to the second embodiment of the invention.

The vapor chamber 2 shown in FIG. 10 includes a housing 10A, a working medium 20, and multiple wicks 30. As shown in FIG. In the vapor chamber 2 shown in FIG. 10, the planar shape of the housing 10A is L-shaped. The planar shape of the housing 10A may be, for example, a stepped shape. As in FIG. 2, the plurality of wicks 30 includes, for example, six wicks 31, 32, 33, 34, 35 and 36. FIG.

FIG. 11 is a plan view schematically showing another example of the vapor chamber according to the second embodiment of the invention.

A vapor chamber 2A shown in FIG. 11 includes a housing 10A, a working medium 20, and a plurality of wicks 30A. In the vapor chamber 2A shown in FIG. 11, the planar shape of the housing 10A is L-shaped as in FIG. The plurality of wicks 30A includes, for example, six wicks 31, 32, 33, 34, 35 and 36A. The wick 36A, like the wick 36, extends to the wall surface of the housing 10A located below the evaporator EP, and then further extends along the wall surface.

As shown in FIGS. 10 and 11, wick 30 or 30A such as wick 31 preferably extends linearly regardless of the planar shape of housing 10A, and may extend along the planar shape of housing 10A. more preferred. Thereby, for example, the working medium 20 can be circulated over a short distance from the evaporation part EP to the condensation part CP.

In the heat diffusion device of the present invention, the planar shape of the housing when viewed in the thickness direction is not particularly limited, and examples thereof include polygonal shapes such as triangles and rectangles, circular shapes, elliptical shapes, and shapes combining these shapes. Further, the planar shape of the housing may be L-shaped, C-shaped (U-shaped), step-shaped, or the like. Further, the housing may have a through hole inside. The planar shape of the housing may be a shape according to the application of the heat diffusion device, the shape of the location where the heat diffusion device is installed, and other parts existing nearby.

[Third Embodiment]
In a third embodiment of the invention, wicks are arranged throughout the interior space of the housing.

FIG. 12 is a plan view schematically showing an example of the vapor chamber according to the third embodiment of the invention.

The vapor chamber 3 shown in FIG. 12 includes a housing 10, a working medium 20, and multiple wicks 30B. In this embodiment, for example, five wicks 31, 32, 33, 34 and 37 are included as the plurality of wicks 30B.

In FIG. 12, wicks 31, 32, 33 and 34 each extend below evaporator EP. On the other hand, the wick 37 extends along the outer periphery of the internal space of the housing 10 . As shown in FIG. 12, the wicks 30B are preferably arranged so as to be concentrated in the evaporating section EP. Specifically, the wicks 31, 32, 33 and 34 are preferably arranged so that the first end E1 is concentrated in the evaporating part EP, and the wick 37 has the first end E1 and the second end E2 of the evaporating part EP. It is preferable that they are arranged so as to be concentrated in the part EP.

It is preferable that the first steam flow path 51 is formed between adjacent wicks 30B as in FIG.

[Fourth Embodiment]
In the fourth embodiment of the present invention, wicks are arranged only in the outer peripheral portion of the internal space of the housing.

FIG. 13 is a plan view schematically showing an example of the vapor chamber according to the fourth embodiment of the invention.

The vapor chamber 4 shown in FIG. 13 comprises a housing 10, a working medium 20 and one wick 30C. In this embodiment, the wick 30C is arranged only in the outer peripheral portion of the internal space of the housing 10 .

In FIG. 13, the wick 30C extends along the outer periphery of the internal space of the housing 10. In FIG. As shown in FIG. 13, the wick 30C is preferably arranged such that the first end E1 and the second end E2 converge on the evaporator EP.

A vapor flow path 50 is preferably formed in the space surrounded by the wick 30C.

[Other embodiments]
The heat diffusion device of the present invention is not limited to the above-described embodiments, and various applications and modifications can be made within the scope of the present invention regarding the structure of the heat diffusion device, manufacturing conditions, and the like.

In the heat diffusion device of the present invention, a plurality of wicks may be arranged between the first inner wall surface and the second inner wall surface of the housing. In that case, the plurality of wicks extend from the first end to the second end so as to be parallel to each other in plan view from the thickness direction of the first inner wall surface.

In the heat spreading device of the present invention, one wick may be arranged between the first inner wall surface and the second inner wall surface of the housing. In that case, the wick extends from the first end to the second end in plan view from the thickness direction of the first inner wall surface.

In the heat diffusion device of the present invention, when the housing is composed of the first sheet and the second sheet, the first sheet and the second sheet may be overlapped so that the edges are aligned, or the edges may overlap. may be shifted and overlapped.

In the heat diffusion device of the present invention, when the housing is composed of the first sheet and the second sheet, the material of the first sheet may be different from the material of the second sheet. For example, by using a high-strength material for the first sheet, the stress applied to the housing can be dispersed. Also, by using different materials for the two sheets, one sheet can have one function and the other sheet can have another function. The above functions are not particularly limited, but include, for example, a heat conduction function, an electromagnetic wave shielding function, and the like.

In the heat diffusion device of the present invention, the wick may have a constant width in the thickness direction or may not have a constant width in the thickness direction in a cross section perpendicular to the direction in which the wick extends. For example, in a cross section perpendicular to the direction in which the wick extends, the width of the end on the second inner wall surface side of the wick may be narrower than the width of the end on the first inner wall surface side. The width of the end portion on the first inner wall surface side may be narrower than the width of the portion. In these cases, portions of constant width may be included.

In the heat diffusion device of the present invention, the housing may have multiple evaporators.

In the heat diffusion device of the present invention, a plurality of struts may be arranged in the vapor channel to support the first inner wall surface and the second inner wall surface of the housing from the inside.

When a plurality of pillars are arranged in the steam flow path, the steam flow path is divided between the pillars. The column supports the first inner wall surface and the second inner wall surface of the housing from the inside. If the number of wicks is small, it is possible to support the enclosure by placing stanchions in the vapor flow path.

When a plurality of struts are arranged in the steam flow path, it is preferable that the struts are arranged in all the steam flow paths, but there may be steam flow paths in which no struts are arranged.

The post may be in contact with both the first inner wall surface and the second inner wall surface, or may be in contact with either one of the first inner wall surface and the second inner wall surface. may not touch both

Materials forming the pillars are not particularly limited, but examples thereof include resins, metals, ceramics, mixtures thereof, laminates, and the like. Further, the pillars may be integrated with the housing, and may be formed, for example, by etching the inner wall surface of the first sheet or the second sheet.

The shape of the column 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 column include polygons such as rectangles, circles, ovals, and the like.

The height of the support is not particularly limited, and may be the same as or different from the height of the wick.

The height of the struts may be the same or different in one heat spreading device. For example, the height of the struts in one region may differ from the height of the struts in another region.

The width of the support is not particularly limited as long as it provides strength capable of suppressing deformation of the housing of the heat diffusion device. or less, preferably 300 μm or more and 1000 μm or less. By increasing the equivalent circle diameter of the support, deformation of the housing of the heat diffusion device can be further suppressed. On the other hand, by reducing the circle-equivalent diameter of the strut, it is possible to secure a wider space for the vapor of the working medium to move.

Although the arrangement of the pillars is not particularly limited, they are preferably arranged evenly in a predetermined area, more preferably evenly over the entire area, for example, so that the distance between the pillars is constant. Evenly distributed struts ensure uniform strength throughout the heat spreader device.

The heat spreading device of the present invention may further comprise wicks other than the wicks described above. For example, the heat spreading device of the present invention may further include at least one of a wick arranged along the first inner wall surface and a wick arranged along the second inner wall surface.

The wick arranged along the first inner wall surface and the wick arranged along the second inner wall surface are not particularly limited as long as they have a capillary structure capable of moving the working medium by capillary force. The capillary structure of the wick may be any known structure used in conventional heat spreading devices. The capillary structure includes fine structures having unevenness such as pores, grooves, and projections, such as porous structures, fiber structures, groove structures, and network structures.

The materials of the wick arranged along the first inner wall surface and the wick arranged along the second inner wall surface are not particularly limited, and examples thereof include metal porous films, meshes, non-woven fabrics, etc. formed by etching or metal processing. A sintered body, a porous body, or the like is 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. . The porous body that is the material of the wick may be composed of, for example, a metal porous body, a ceramic porous body, or a resin porous body.

The size and shape of the wick arranged along the first inner wall surface and the wick arranged along the second inner wall surface are not particularly limited. It is preferable to have a size and shape that can be installed on the floor.

The thickness of the wick arranged along the first inner wall surface and the thickness of the wick arranged along the second inner wall surface are not particularly limited, but each is, for example, 2 μm or more and 200 μm or less, preferably 5 μm or more and 100 μm or less, It is more preferably 10 μm or more and 40 μm or less. The thickness of the wick arranged along the first inner wall surface and the wick arranged along the second inner wall surface may be partially different. The thickness of the wick arranged along the first inner wall surface may be the same as or different from the thickness of the wick arranged along the second inner wall surface.

The heat diffusion device of the present invention can be mounted on electronic equipment for the purpose of heat dissipation. Therefore, an electronic device including the heat diffusion device of the present invention is also one aspect of the present invention. Examples of the electronic device of the present invention include smart phones, tablet terminals, notebook computers, game machines, wearable devices, and the like. As described above, the heat diffusion device of the present invention can operate independently without requiring external power, and can diffuse heat two-dimensionally and at high speed by utilizing the latent heat of vaporization and latent heat of condensation of the working medium. 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.

In the electronic device of the present invention, the first region of the heat diffusion device of the present invention is preferably a region in which a heat source is arranged. For example, it is preferable that an integrated circuit (IC) is arranged in the first region on the outer wall surface of the housing that constitutes the heat diffusion device of the present invention. Further, it is preferable that the total area of the wick overlapping the integrated circuit is 15% or more of the total area of the integrated circuit when viewed from the thickness direction of the first inner wall surface. In addition, in plan view from the thickness direction of the first inner wall surface, the wick overlapping the integrated circuit and the integrated circuit having a length of 30% or more with respect to the distance from the center to the edge of the integrated circuit and the edge from the center to the edge of the integrated circuit. Preferably, there is a wick that overlaps the integrated circuit with a length of no less than 15% and less than 30% of the distance to the part.

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, 2, 2A, 3, 4 vapor chamber (heat diffusion device)
10, 10A housing 11 first sheet 11a first inner wall surface 12 second sheet 12a second inner wall surface 20 working medium 30, 30A, 30B, 30C, 31, 32, 33, 34, 35, 36, 36A, 37 wick 50 Steam channel 51 First steam channel 52 Second steam channel 53 Third steam channel F Fiber E1 First end E2 Second end P1 First part P2 Second part P3 Third part R1 First region R2 Second 2nd region R3 3rd region CP Condensing part EP Evaporating part HS Heat source X Width direction Y Length direction Z Thickness direction

Claims (17)

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;
at least one wick disposed between the first inner wall surface and the second inner wall surface of the housing;
The wick extends from a first end to a second end in plan view from the thickness direction of the first inner wall surface,
The wick is composed of a fiber bundle in which fibers are linearly bundled,
When viewed in cross section along the direction in which the wick extends and the thickness direction, the first end of the wick is located in the first region of the housing, and the first end and the second end of the wick are located in the first region of the housing. A part excluding the end is located in a second region different from the first region of the housing,
The wick has a first portion in contact with the first inner wall surface and not in contact with the second inner wall surface in the first region, and has the first inner wall surface and the second inner wall surface in the second region. having a second portion contacting the
The heat diffusion device, wherein the first portion of the wick is thicker than the second portion of the wick in plan view from the thickness direction of the first inner wall surface. 2. The heat spreading device of claim 1, wherein said first portion of said wick comprises said first end of said wick. 3. The heat spreading device of claim 1 or 2, wherein the first region is located in the evaporator section. a plurality of the wicks are arranged between the first inner wall surface and the second inner wall surface of the housing;
4. Any one of claims 1 to 3, wherein the plurality of wicks extend from the first end to the second end so as to be parallel to each other in plan view from the thickness direction of the first inner wall surface. A heat spreading device according to any one of claims 1 to 3 . 5. The heat spreading device according to claim 4, wherein the first portion of one of the adjacent wicks and the first portion of the other of the wicks are connected. 5. The heat spreading device of claim 4, wherein the first portion of one of the adjacent wicks is separated from the first portion of the other of the wicks. In a plan view from the thickness direction of the first inner wall surface, among the plurality of wicks, the wicks away from the center are longer than the wicks located inside the wicks, A heat spreading device according to any one of claims 4 to 6, wherein the edge is protruding. The heat diffusion device according to any one of claims 4 to 7, wherein a first vapor channel is formed between adjacent said wicks. 9. A second steam channel wider than the first steam channel is formed between one of the plurality of wicks positioned on the outermost side and the housing. A heat spreading device as described in . 10. The thermal diffusion according to claim 9, further comprising a third steam channel wider than the first steam channel is formed between the other outermost wick and the housing. device. The heat spreading device according to any one of claims 1 to 10, wherein a cross section of said fibers perpendicular to the direction in which said wick extends has a flattened shape. The second end of the wick is located in a third region different from the first region and the second region of the housing when viewed in cross section along the direction in which the wick extends and the thickness direction. ,
The wick according to any one of claims 1 to 11, wherein, in the third region, the wick has a third portion in contact with one of the first inner wall surface and the second inner wall surface and not in contact with the other inner wall surface. A heat spreading device according to any one of the preceding claims . 13. The heat spreading device of claim 12, wherein said third portion of said wick comprises said second end of said wick. 14. A heat spreading device according to claim 12 or 13, wherein the third region is located in the condensation section. The heat according to any one of claims 12 to 14, wherein the third portion of the wick is thicker than the second portion of the wick in plan view from the thickness direction of the first inner wall surface. diffusion device. An electronic device comprising the heat spreading device according to any one of claims 1 to 15. further comprising an integrated circuit,
17. The electronic device according to claim 16, wherein said first area is an area in which said integrated circuit is arranged.

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