JP6988170B2 - Vapor chamber - Google Patents

Description

The present invention relates to a vapor chamber.

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 have become important. This situation is particularly noticeable in the field of mobile terminals such as smartphones and tablets. In recent years, a graphite sheet or the like is often used as a heat countermeasure member, but since the heat transport amount thereof is not sufficient, the use of various heat countermeasure members is being considered. In particular, the use of a vapor chamber, which is a planar heat pipe, is being studied because it can diffuse heat very effectively.

The vapor chamber is a flat plate-shaped closed container in which an appropriate amount of working fluid that easily volatilizes is sealed. The working fluid is vaporized by the heat from the heat source, moves in the internal space, and then releases heat to the outside to return to the liquid. The working fluid that has returned to liquid is carried to the vicinity of the heat source again by a capillary structure called a wick, and is vaporized again. 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 fluid.

Patent Document 1 describes a heat pipe having a condensing portion where the working fluid condenses and an evaporating portion where the working fluid evaporates. In Patent Document 1, a working fluid is sealed inside the heat pipe container, and a wick structure having a nanometer-order uneven structure is formed on both the inner wall of the lower container and the inner wall of the upper container. With such a configuration, two-dimensional heat diffusion is achieved.

Japanese Unexamined Patent Publication No. 2012-057841

Since the vapor chamber needs to be used in close proximity to a high temperature heat source, it is preferable that the performance does not deteriorate due to a change in ambient temperature. However, when the temperature of the vapor chamber becomes high, impurity gas may be generated inside. Such impurity gases can change the desired heat transport properties of the vapor chamber. Further, when the above-mentioned impurity gas is trapped in the wick, the hydrophilicity of the wick is lowered, and the heat transport characteristics of the vapor chamber may be lowered. If a wick structure having an uneven structure on the order of nanometers is formed on both the inner wall of the lower container and the inner wall of the upper container as in Patent Document 1, the impurity gas can be trapped by the wick, but at the same time, the wick can be trapped. The hydrophilicity may decrease and the heat transport characteristics of the vapor chamber may decrease. Further, by providing the wick on both the inner wall of the lower container and the inner wall of the upper container, there is a concern that the portion where the working fluid that has become vapor moves becomes narrow.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a vapor chamber in which performance is unlikely to be deteriorated even by a change in ambient temperature.

In order to solve the above problems, the vapor chamber according to a certain aspect of the present invention includes a housing, a pillar arranged in the internal space of the housing so as to support the housing from the inside, and the housing. It has a hydraulic fluid enclosed in an internal space and a wick arranged in the internal space of the housing, and at least a part of the main inner surface of the housing is exposed to the internal space of the housing, and is averaged. It has pores with a depth of 10 nm or more.

Further, in the vapor chamber of one embodiment, the average depth of the pores on the main inner surface of the housing is 40 nm or less.

Further, in the vapor chamber of one embodiment, the average diameter of the pores on the main inner surface of the housing is 10 nm or more and 100 nm or less.

Further, in the vapor chamber of one embodiment, pores having an average depth of 10 nm or more are provided in at least a part of the pillar.

Further, in the vapor chamber of one embodiment, the average depth of the pores of the pillar is 40 nm or less.

Further, in the vapor chamber of one embodiment, the average diameter of the pores of the pillar is 10 nm or more and 100 nm or less.

Further, in the vapor chamber of one embodiment, a convex portion having a height of 1 μm or more and 100 μm or less is formed on the main inner surface of the housing facing the main inner surface of the housing.

Further, in the vapor chamber of one embodiment, the housing is composed of two opposing sheets whose outer edges are sealed.

Further, in the vapor chamber of one embodiment, the wick is in contact with the main inner surface facing the main inner surface having the pores in at least a part thereof.

Further, according to the present invention, there is provided a heat dissipation device comprising the vapor chamber of the present invention.

Further, according to the present invention, there is provided an electronic device comprising the vapor chamber of the present invention or the heat dissipation device of the present invention.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a vapor chamber that does not narrow the portion where the working fluid that has become vapor moves and does not cause a deterioration in performance due to a change in ambient temperature.

It is sectional drawing of the vapor chamber of one Embodiment of this invention. It is a schematic diagram of the cross section of the main inner surface having pores of the vapor chamber of one Embodiment of this invention. It is sectional drawing of the vapor chamber of one Embodiment of this invention. It is a schematic diagram of the convex part of the main inner surface of the vapor chamber of one Embodiment of this invention. It is a schematic diagram of the convex part of the main inner surface of the vapor chamber of one Embodiment of this invention. 6 is an SEM image of a cross section of a main inner surface having pores of a vapor chamber according to an embodiment of the present invention. 6 is an SEM image of a cross section of a main inner surface having pores of a vapor chamber according to an embodiment of the present invention. 6 is an SEM image of a cross section of a main inner surface having pores of a vapor chamber according to an embodiment of the present invention. It is sectional drawing of the vapor chamber of one Embodiment of this invention. It is an upper perspective view of the upper housing sheet of the vapor chamber of one embodiment of the present invention and the lower housing sheet having a joining layer.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

1 and 3 are cross-sectional views of the vapor chambers 1a and 1b of the embodiment of the present invention, respectively. As shown in FIGS. 1 and 3, the vapor chamber of the present invention includes a housing 2, a pillar 3 arranged in an internal space of the housing 2 so as to support the housing 2 from the inside, and a housing. It has a wick 4 arranged in the internal space of 2. Further, although not shown, the vapor chamber of the present invention further has a working fluid enclosed in the internal space of the housing 2. As shown in FIGS. 1 and 3, at least a part of the main inner surface of the housing 2 is exposed to the internal space of the housing 2.

FIG. 2 is a partially enlarged view schematically showing a portion having pores 10 on the main inner surface exposed in the internal space of the housing 2 of the vapor chamber of the present invention. The average depth of the pores 10 is 10 nm or more. At least a part of the main inner surface of the housing 2 of the vapor chamber of the present invention is exposed in the internal space of the housing 2, and the vapor chamber has pores 10 having an average depth of 10 nm or more. Impurity gas that may be generated inside when the temperature becomes high can be trapped in the pores 10. As a result, the amount of the impurity gas adhering to the wick 4 can be effectively reduced, and the decrease in the heat transport capacity of the vapor chamber can be suppressed. Further, by using the pores 10 on the main inner surface exposed in the internal space of the housing 2 for trapping the impurity gas, the impurity gas can be trapped without narrowing the portion where the working liquid which has become vapor moves. Can be done.

Hereinafter, each configuration of the vapor chamber of the present invention will be described in detail.

The housing 2 of the vapor chamber of the present invention may be provided with two opposing main inner surfaces. The shape of the main inner surface of the housing 2 may be polygonal or circular. In the present specification, the main inner surface means a surface having the largest area among the surfaces defining the internal space of the housing 2 and a surface facing the surface.

The height A (that is, the thickness of the vapor chamber) of the housing 2 shown by A in FIG. 1 may be, for example, 100 μm or more and 600 μm or less, preferably 200 μm or more and 500 μm or less. The width B (that is, the width of the vapor chamber) of the housing 2 shown by B in FIG. 1 may be, for example, 5 mm or more and 500 mm or less, preferably 20 mm or more and 300 mm or less. Although not shown, the depth D (that is, the depth of the vapor chamber) of the housing 2 extending from the front to the back of the paper, which is orthogonal to the arrow indicating the width B of the housing 2 in FIG. 1, is, for example, 5 mm or more and 500 mm. It may be less than or equal to, and is preferably in the range of 20 mm or more and 300 mm or less. The height A, width B, and depth D described above may be uniform or different at any location in the housing 2.

The housing 2 may be integrally formed of a single member, and may consist of two opposing sheets with outer edges sealed, for example, as shown in FIGS. 1 and 3. You may. Further, it may be formed from two or more plate-shaped members. In the vapor chambers 1a and 1b of FIGS. 1 and 3, the upper housing sheet 6 forms the upper main inner surface of the housing 2, and the lower housing sheet 7 forms the lower main inner surface of the housing 2. In the housing 2, the upper housing sheet 6 and the lower housing sheet 7 are sealed to each other at their respective outer edges. The outer edge portion of the upper housing sheet 6 and the lower housing sheet 7 refers to a region having a predetermined distance inward from the end portion of the sheet. In the vapor chambers of FIGS. 1 and 3, the outer edge portion of the upper housing sheet 6 and the outer edge portion of the lower housing sheet 7 are sealed by laser welding, but the method of sealing the outer edge portion is this. It is not limited to this, and can be sealed by, for example, resistance welding, diffusion welding, brazing, TIG welding, resin sealing, or the like.

The material forming the housing 2 is not particularly limited, and for example, copper, nickel, aluminum, magnesium, titanium, iron, and alloys containing them as main components can be used, and copper is preferably used.

When the housing 2 is formed by sealing the upper housing sheet 6 and the lower housing sheet 7 at the outer edge portion, the upper housing sheet 6 and the lower housing sheet 7 are both made of the same material. It may be formed or may be formed from two different materials respectively.

The thickness C (thickness of the housing sheet in the illustrated example) constituting the housing 2 represented by C in FIG. 1 may be, for example, 10 μm or more and 200 μm or less, preferably 30 μm or more and 150 μm or less. It is in the range of 30 μm or more and 100 μm or less, and more preferably 40 μm or more and 60 μm or less. The thickness C described above may be uniform or different at any location in the housing 2. The thickness C of the upper housing sheet 6 and the thickness of the lower housing sheet 7 may be different.

Here, in the vapor chamber of one embodiment of the present invention, the housing is composed of two opposing sheets whose outer edges are sealed, and the thermal conductivity of at least one of the two sheets is 1 W / (m). It may be k) or more and 100 W / (m · k) or less.

In the present invention, the upper housing sheet 6 and the lower housing sheet 7 can each be formed of a material having an arbitrary thermal conductivity, and for example, 1 W / (m · k) or more, more preferably 10 W / (. It may be formed from a material having a thermal conductivity of m · k) or more and 100 W / (m · k) or less, more preferably 50 W / (m · k) or less. When the thermal conductivity of at least one of the upper housing sheet 6 and the lower housing sheet 7 is 1 W / (m · k) or more, effective heat diffusion becomes possible. Further, since the thermal conductivity of at least one of the upper housing sheet 6 and the lower housing sheet 7 is 100 W / (m · k) or less, the heat given to the outer edge portion when the two sheets are welded is generated. Since it can be effectively fastened to the outer edge without being diffused, the efficiency of the welding process can be improved. In addition, the thermal conductivity in the direction perpendicular to the main surface of the vapor chamber can be lowered, and it can be effectively used in applications where heat is not desired to be transferred in this direction. For example, in a mobile phone or the like, by installing the vapor chamber between the heat source and the battery, the liquid crystal display, etc. so as to block the two, it is possible to suppress the transfer of heat to the battery, the liquid crystal display, or the like.

As a material having a thermal conductivity of 1 W / (m · k) or more and 100 W / (m · k) or less, for example, SUS444 (26.0 W / 26.0 W /) which is an alloy containing TiCu (54 W / (m · k)) and titanium. (M · k)), SUS304 (16.7 W / (m · k)) which is an alloy containing nickel, SUS316 (16.7 W / (m · k)) which is an alloy containing nickel, and the like. Can be done.

In the above embodiment, the upper housing sheet 6 and the lower housing sheet 7 may not be provided with the pores 10 described in detail later. That is, the housing, the pillars arranged in the internal space of the housing so as to support the housing from the inside, the hydraulic fluid enclosed in the internal space of the housing, and the internal space of the housing. The housing is composed of two opposing sheets whose outer edges are sealed, and the thermal conductivity of at least one of the two sheets is 1 W / (m · k) or more. A vapor chamber of 100 W / (m · k) or less may be provided.

In the vapor chamber of one embodiment of the present invention, the housing is composed of two opposing sheets whose outer edges are sealed, and the two sheets have different rigidity from each other.

In the present invention, the upper housing sheet 6 and the lower housing sheet 7 may each have arbitrary rigidity, but it is preferable that the upper housing sheet 6 and the lower housing sheet 7 have different rigidity from each other. In the present specification, the rigidity of the housing sheet means the difficulty of deformation of the housing sheet due to a force such as bending. Since the rigidity of the upper housing sheet 6 and the rigidity of the lower housing sheet 7 are different from each other, one of the housing sheets having a lower rigidity is easily deformed when the outer edge portion is sealed, whereby the two housing sheets are easily deformed. Since the adhesion at the outer edge portion of the housing sheet is improved, a vapor chamber having a larger joint strength at the outer edge portion can be obtained. When the rigidity of the upper housing sheet 6 is larger than the rigidity of the lower housing sheet 7, the vapor chamber is less likely to be crushed by the pressure from the upper housing side. When the rigidity of the lower housing sheet 7 is larger than the rigidity of the upper housing sheet 6, the vapor chamber is less likely to be crushed by the pressure from the lower housing side.

In the above embodiment, the upper housing sheet 6 and the lower housing sheet 7 may have different rigidity by being formed of materials having different Young's moduli. As a result, it is possible to effectively reduce the deformation of the housing sheet having a small Young's modulus when pressure is applied to the housing from the housing sheet side having a large Young's modulus. The upper housing sheet 6 and the lower housing sheet 7 can be formed of arbitrary materials having different Young's moduluss from each other. For example, the upper housing sheet 6 may be formed of Cu, and the lower housing sheet 7 may be formed of TiCu having a Young's modulus higher than that of Cu.

FIG. 9 is a cross-sectional view of the vapor chamber 1c according to the embodiment of the present invention. In the above embodiment, the upper housing sheet 6 and the lower housing sheet 7 may have different thicknesses as shown in FIG. When the upper housing sheet 6 and the lower housing sheet 7 are formed to have different thicknesses as described above, the upper housing sheet 6 and the lower housing sheet 7 are formed of the same material. However, they may have different stiffnesses from each other. Specifically, when the upper housing sheet 6 and the lower housing sheet 7 are made of the same material, the housing sheet having a larger thickness has a large rigidity. As a result, the vapor chamber is less likely to be crushed by the pressure from the housing sheet side having a large thickness. In addition, by appropriately setting the ratio of the thickness of the upper housing sheet to the thickness of the lower housing sheet, a small thickness can be obtained when pressure is applied to the housing from the housing sheet side having a large thickness. It is possible to effectively reduce the deformation of the housing sheet to be held.

In the above embodiment, the upper housing sheet 6 and the lower housing sheet 7 may not be provided with pores to be described in detail later. That is, the housing, the pillars arranged in the internal space of the housing so as to support the housing from the inside, the hydraulic fluid enclosed in the internal space of the housing, and the internal space of the housing. A vapor chamber may be provided in which the housing comprises two opposing sheets with sealed outer edges, the two sheets having different stiffnesses from each other.

FIG. 10 is an upward perspective view showing an upper housing sheet 6 and a lower housing sheet 7 forming a housing 2 of a vapor chamber according to an embodiment of the present invention, and a bonding layer 8. In FIG. 10, the upper housing sheet 6 and the lower housing sheet 7 are described separately, but in the vapor chamber of the present invention, the outer edges of both are sealed, and one housing 2 is used. Form. That is, in the vapor chamber of the embodiment, the housing has two facing housing sheets 6 and 7 whose outer edges are sealed and a joining layer 8 located between the outer edges of the two housing sheets. And have.

In the vapor chamber of one embodiment of the present invention, the bonding layer 8 is made of a material having a lower thermal conductivity than the material forming the housing sheet. The two sheets are welded by locating a joining layer 8 made of a material having a lower thermal conductivity than the material forming the housing sheet between the outer edges of the upper housing sheet 6 and the lower housing sheet 7. Since a part of the heat applied to the outer edge portion can be effectively retained in the joint layer 8 of the outer edge portion without being diffused, the efficiency of the welding process can be improved. Any material having a lower thermal conductivity than the material forming the housing sheet can be used for the bonding layer 8. For example, when the upper housing sheet 6 and the lower housing sheet 7 are formed of Cu, Ni or the like having a lower thermal conductivity than Cu can be used as a material for forming the bonding layer 8.

In the above embodiment, the upper housing sheet 6 and the lower housing sheet 7 are provided with a bonding layer 8 made of a material having a lower thermal conductivity than the material forming the housing sheet between them, all around the housing. By being sealed with, it becomes possible to more effectively suppress the conduction of heat to the portion inside the outer edge portion, and it is possible to further improve the efficiency of the welding process. Further, the outer edge portion may have a portion where the joining layer 8 and the joining layer 8 are provided apart from each other. For example, the bonding layer 8 may be formed without being provided only in the portion where the vacuum pump is inserted in order to reduce the pressure inside the vapor chamber body.

In the above embodiment, by appropriately setting the thickness of the joining layer 8, the upper housing sheet 6 and the lower housing sheet 7 can be joined with sufficient strength. Further, by appropriately setting the thickness of the joining layer 8, the gap formed in the portion where the joining layer 8 is not provided does not become too large, and the upper housing sheet 6 and the lower housing sheet 7 are sufficiently strong. And can be joined so as to have airtightness. The thickness of the joining layer 8 may be uniform over the entire joining layer 8 or may vary from place to place. For example, the bonding layer 8 may be formed so that the thickness is reduced only at the portion where the vacuum pump is inserted in order to reduce the pressure inside the vapor chamber body.

In the above embodiment, the upper housing sheet 6 and the lower housing sheet 7 may not be provided with the pores 10 described in detail later. That is, the housing, the pillars arranged in the internal space of the housing so as to support the housing from the inside, the hydraulic fluid enclosed in the internal space of the housing, and the internal space of the housing. The housing is composed of two opposing sheets whose outer edges are sealed, and the bonding layer 8 is located between the outer edges of the two housing sheets. A vapor chamber may be provided.

In the vapor chamber of one embodiment of the present invention, the bonding layer 8 is made of a material having a melting point lower than that of the material forming the housing sheet. By locating a bonding layer 8 made of a material having a melting point lower than that of the material forming the housing sheet between the outer edges of the upper housing sheet 6 and the lower housing sheet 7, the outer edge is welded at a lower temperature. Therefore, the efficiency of the welding process can be improved. Any material having a melting point lower than that of the material forming the housing sheet can be used for the bonding layer 8. For example, when the upper housing sheet 6 and the lower housing sheet 7 are formed of Cu, a bulk Sn alloy or the like having a melting point lower than that of Cu can be used as a material for forming the bonding layer 8.

In the above embodiment, the upper housing sheet 6 and the lower housing sheet 7 are sealed by providing a bonding layer 8 made of a material having a melting point lower than that of the material forming the housing sheet between them on the entire circumference of the housing. By being stopped, the upper housing sheet 6 and the lower housing sheet 7 can be joined with sufficient strength. Further, the outer edge portion may have a portion where the joining layer 8 and the joining layer 8 are provided apart from each other. For example, the bonding layer 8 may be formed without being provided only in the portion where the vacuum pump is inserted in order to reduce the pressure inside the vapor chamber body.

In the above embodiment, by appropriately setting the thickness of the joining layer 8, the upper housing sheet 6 and the lower housing sheet 7 can be joined with sufficient strength. Further, by appropriately setting the thickness of the joining layer 8, the gap formed in the portion where the joining layer 8 is not provided does not become too large, and the upper housing sheet 6 and the lower housing sheet 7 are sufficiently strong. And can be joined so as to have airtightness. The thickness of the joining layer 8 may be uniform over the entire joining layer 8 or may vary from place to place. For example, the bonding layer 8 may be formed so that the thickness is reduced only at the portion where the vacuum pump is inserted in order to reduce the pressure inside the vapor chamber body.

In the above embodiment, the upper housing sheet 6 and the lower housing sheet 7 may not be provided with the pores 10 described in detail later. That is, the housing, the pillars arranged in the internal space of the housing so as to support the housing from the inside, the hydraulic fluid enclosed in the internal space of the housing, and the internal space of the housing. The housing is composed of two opposing sheets whose outer edges are sealed, and the bonding layer 8 is located between the outer edges of the two housing sheets. A vapor chamber may be provided.

At least a part of the main inner surface of the housing 2 is exposed to the internal space of the housing 2, and the exposed portion has pores 10 having an average depth of 10 nm or more as shown in FIG. is doing. In the present specification, the portion "exposed" to the internal space of the main inner surface of the housing 2 is a portion of the housing 2 that can come into contact with the gas in the internal space, for example, the wick 4, the pillar 3, and other members. It is a part that does not touch. Since the pores 10 having an average depth of 10 nm or more are provided on the main inner surface of the housing 2, the impurity gas can be trapped by the pores 10. As a result, the amount of impurity gas adhering to the wick 4 can be reduced, and the decrease in the heat transport capacity of the vapor chamber can be suppressed.

As used herein, the term "impurity gas" refers to a gas other than the components contained in the working liquid existing in the internal space of the housing 2. For example, the component of the rust preventive agent adhering to the metal foil constituting the housing 2 may be generated by gasifying the housing 2 due to the high temperature. Examples of the component of the impurity gas include alcohol-based, hydrocarbon-based, aromatic-based, and carbon dioxide-based gas.

In the present specification, the average depth of the pores 10 is defined as the pores of pores having a depth of 5 nm or more and a diameter of 300 nm or less by observing a cross section with a length of 1 μm at three arbitrary positions on the main inner surface. The value measured by measuring the average value of the depth of. The average depth of the pores 10 of the vapor chamber of the present invention is 10 nm or more, preferably 20 nm or more, and more preferably 30 nm or more. When the average depth of the pores 10 is 10 nm or more, a sufficient amount of impurity gas can be trapped in the pores 10 on the main inner surface, and the trapped impurity gas is less likely to be released.

The average depth of the pores 10 on the main inner surface is preferably 40 nm or less. When the average depth of the pores 10 is 40 nm or less, embrittlement of the main inner surface can be effectively prevented.

The average diameter of the pores 10 on the main inner surface is in the range of 10 nm or more and 100 nm or less, more preferably in the range of 10 nm or more and 80 nm or less, and further preferably in the range of 10 nm or more and 50 nm or less. When the average diameter of the pores 10 on the main inner surface is 10 nm or more, it becomes possible to effectively trap the impurity gas. When the average diameter of the pores 10 on the main inner surface is 100 nm or less, the possibility that the working liquid is trapped in the pores 10 on the main inner surface can be significantly reduced. Further, when the average diameter of the pores 10 on the main inner surface is 50 nm or less, it is possible to prevent the working liquid from invading the pores 10, and it is possible to substantially trap only the gas.

In the present specification, the average diameter of the pores 10 is a pore having a depth of 5 nm or more and a diameter of 300 nm or less, which is observed when a cross-sectional observation is performed with a length of 1 μm at three arbitrary positions on the main inner surface. The average value of the diameter of.

The average number of pores 10 provided per ^{1 μm 2 of} the surface defining the internal space of the housing 2 is
The number may be 10 or more and 1000 or less, preferably 30 or more and 400 or less, and more preferably 50 or more and 200 or less. When the temperature of the housing 2 becomes high, impurity gas derived from the component of the rust preventive agent may be generated from the portion exposed to the internal space of the housing 2 to the internal space. Since the amount of impurity gas generated at this time is proportional to the area of the surface defining the internal space of the housing 2, an average of 10 or more pores 10 are formed per ^{1 μm 2 of the surface defining the internal space of the housing 2.} By providing it, it becomes possible to effectively trap the generated impurity gas. ^{Further, since the number of pores 10 provided per 1 μm 2 of} the surface defining the internal space of the housing 2 is 1000 or less on average, embrittlement of the main inner surface having the pores 10 is effectively prevented. be able to.

The method of forming the pores 10 is not particularly limited, and examples thereof include a method of forming by surface treatment such as etching and blasting, and examples of other methods include plating and thermal spraying. When the pores 10 are formed by etching, the average depth, the average diameter, and the housing 2 of the pores 10 formed by adjusting the conditions such as the type of etching solution used, the etching temperature, and the etching time are adjusted. It is possible to control the average number of pores 10 provided per ^{1 μm 2 of} the surface that defines the internal space of the.

The pillar 3 is arranged in the internal space of the housing 2 so as to support the housing 2 from the inside. The pillar 3 may be integrally formed with the housing 2 in the internal space of the housing 2, or may be joined to the housing 2. By arranging the pillar 3 in the internal space of the housing 2, it is possible to reduce the deformation of the housing 2 when a load is applied to the housing 2.

In the vapor chamber of the present invention, the pores 10 having an average depth of 10 nm or more provided on the main inner surface of the housing 2 are similarly provided on at least a part of the portion of the pillar 3 exposed to the internal space of the housing 2. It may have been done. The average depth of the pores 10 of the pillar 3 is 10 nm or more, preferably 20 nm or more, and more preferably 30 nm or more. Since the pillar 3 is also provided with the pores 10 having an average depth of 10 nm or more, the pores 10 can more effectively trap the impurity gas. As a result, the amount of impurity gas adhering to the wick 4 can be effectively reduced, and the heat transport capacity of the vapor chamber can be prevented from being lowered.

The average depth of the pores 10 of the pillar 3 is preferably 40 nm or less. This can effectively prevent embrittlement of the main inner surface.

The average diameter of the pores 10 of the pillar 3 is in the range of 10 nm or more and 100 nm or less, more preferably in the range of 10 nm or more and 80 nm or less, and further preferably in the range of 10 nm or more and 50 nm or less. When the average diameter of the pores 10 of the pillar 3 is 10 nm or more, it becomes possible to effectively trap the impurity gas. When the average diameter of the pores 10 of the column 3 is 100 nm or less, the possibility that the working fluid is trapped in the pores 10 of the column 3 can be significantly reduced. Further, when the average diameter of the pores 10 of the column 3 is 50 nm or less, it is possible to prevent the working liquid from entering the pores 10, and it is possible to substantially trap only the gas.

^{The average number of pores 10 per 1 μm 2} of the surface of the pillar 3 may be 10 or more and 1000 or less, preferably 30 or more and 400 or less, and more preferably 50 or more and 200 or less. .. ^{When the number of pores 10 per 1 μm 2} of the surface of the pillar 3 is 10 or more, it becomes possible to effectively trap the impurity gas. ^{Further, when the number of pores 10 per 1 μm 2} of the surface of the pillar 3 is 1000 or less, embrittlement of the surface of the pillar 3 having the pores 10 can be effectively prevented.

As shown in FIG. 3, a convex portion 5 having a height of 1 μm or more and 100 μm or less may be formed on the main inner surface of the housing 2 facing the main inner surface of the housing 2 provided with the pores 10. .. The convex portion 5 may be formed directly on the main inner surface of the housing 2 as shown in FIG. The space between the protrusions 5 can serve to recirculate the working fluid. Therefore, in the vapor chamber of the present invention having the convex portion 5, the reflux of the working liquid is promoted by both the space between the wick 4 and the convex portion 5, so that the efficiency is higher than that of the vapor chamber having no convex portion 5. Thermal diffusion can occur. Further, as shown in FIG. 3, when the convex portion 5 is directly formed on the main inner surface of the housing 2, the area of the main inner surface of the housing 2 exposed to the internal space of the housing 2 increases. As a result, the housing 2 can have more pores 10, so that the pores 10 can more effectively trap the impurity gas. As a result, the amount of impurity gas adhering to the wick 4 can be effectively reduced, and the heat transport capacity of the vapor chamber can be prevented from being lowered.

Instead of forming the convex portion 5, a metal foil having the convex portion 5 may be separately prepared and placed on the main inner surface. By installing the metal foil having the convex portion 5 in the housing as described above, the same effect as when the convex portion 5 is formed on the main inner surface can be obtained.

In the present specification, the convex portion means a portion of the main inner surface of the housing 2 having a height larger than that of the adjacent portion. The convex portion may be formed by providing a protrusion on the main inner surface of the housing 2 or the metal foil, and for example, the groove and the groove provided by providing a plurality of grooves on the main inner surface of the housing 2 or the metal foil. It may be formed between and.

The convex portion 5 of the housing 2 can be formed in an arbitrary shape so as to form a space in which the working liquid can be refluxed between the convex portion 5 and the adjacent convex portion 5. The height E of the convex portion 5 may be, for example, in the range of 1 μm or more and 100 μm or less, and preferably in the range of 5 μm or more and 50 μm or less. The distance F between the convex portion 5 and the adjacent convex portion 5 may be, for example, in the range of 1 μm or more and 500 μm or less, preferably in the range of 5 μm or more and 300 μm or less, and more preferably 15 μm or more and 150 μm or less. It is in the range. When the distance F is within such a range, the working fluid can be effectively refluxed.

The convex portion 5 of the housing 2 is preferably formed in a columnar shape having opposite bottom surfaces parallel to each other. The convex portion 5 of the housing 2 may have, for example, a substantially quadrangular prism shape, a substantially cylindrical shape, or a frustum shape. When the convex portion 5 of the housing 2 is formed in a substantially quadrangular prism shape, the bottom surface of the convex portion 5 has a ratio of the length of the short side to the length of the long side close to 1 as shown in FIG. It may be a quadrangle. Further, as shown in FIG. 5, the ratio of the length of the short side to the length of the long side may be much less than 1. Further, although not shown, the ratio of the length of the short side to the length of the long side may be 1. That is, the bottom surface of the convex portion 5 may be square.

The wick 4 is arranged in the internal space of the housing 2 and serves to recirculate the working liquid. The mode of arrangement of the wick 4 is not particularly limited, and for example, as shown in FIG. 1, the wick 4 may be arranged so as to be sandwiched between the main inner surface of the housing 2 and the pillar 3. Further, as shown in FIG. 2, when the convex portion 5 is formed on the main inner surface of the housing 2 facing the main inner surface of the housing 2 provided with the pores 10, the convex portion 5 and the pillar are formed. It may be arranged so as to be sandwiched between 3 and 3.

The thickness of the wick 4 may be, for example, in the range of 5 μm or more and 200 μm or less, preferably 10 μm or more and 80 μm or less, and more preferably 30 μm or more and 50 μm or less. The thickness of the wick 4 may be uniform or different at any location in the wick 4. Further, the wick 4 does not necessarily have to be formed over the entire main inner surface of the housing 2 of the vapor chamber, and may be partially formed.

The material of the wick 4 is not particularly limited, and for example, a porous body, a mesh, a sintered body, a non-woven fabric, a wire, or the like can be used, and a mesh or a non-woven fabric is preferably used.

The wick 4 is preferably arranged on the main inner surface facing the main inner surface having pores 10 in at least a part thereof. When the wick 4 is arranged on one of the main inner surfaces, the liquid tends to be distributed on the main inner surface side on which the wick 4 is arranged, and the gas tends to be distributed on the main inner surface side facing the main inner surface on which the wick 4 is arranged. Therefore, by arranging the wick 4 on the main inner surface facing the main inner surface having pores 10 at least in a part, gas is easily distributed on the main inner surface side having pores 10, and the pores 10 are impurities. Since it becomes easy to come into contact with the gas, the impurity gas can be effectively trapped in the pores 10.

In the present specification, the state in which the wick 4 is arranged on the main inner surface means that the distance between the main inner surface and the wick 4 is shorter than the distance between the main inner surface facing the main inner surface and the wick 4. Say that. The state in which the wick 4 is arranged on the main inner surface is, for example, a state in which the main inner surface on the lower housing sheet 7 side and the wick 4 are in contact with each other as shown in FIG. 1, and as shown in FIG. A state in which the convex portion 5 on the main inner surface on which the convex portion 5 is formed and the wick 4 are in contact with each other is included. Further, although not shown, the state in which the convex portion 5 of the metal foil having the convex portion 5 placed on the main inner surface and the wick 4 are in contact with each other also states that the wick 4 is arranged on the main inner surface. Included in the "is" state.

Although not shown in FIGS. 1 and 3, a working fluid is further sealed in the housing 2 of the vapor chamber of the present invention. The hydraulic fluid is vaporized by the heat from the heating element and becomes steam. After that, the working liquid that has become vapor moves in the housing 2, releases heat, and returns to the liquid. The working liquid that has returned to the liquid is carried to the heat source again by the capillary phenomenon caused by the wick 4. Then, it is vaporized again by the heat from the heat source and becomes steam. By repeating this, the vapor chamber of the present invention operates independently without requiring external power, and can quickly dissipate heat two-dimensionally by utilizing the latent heat of evaporation and condensation of the working liquid. ..

The type of the hydraulic solution is not particularly limited, and for example, water, alcohols, alternative chlorofluorocarbons and the like can be used, and water is preferably used.

The vapor chamber of the present invention may be mounted on a heat dissipation device so as to be close to a heat source. Accordingly, the present invention also provides a heat dissipation device comprising the vapor chamber of the present invention. When the heat dissipation device of the present invention includes the vapor chamber of the present invention, it is possible to effectively suppress the temperature rise of the electronic component and the periphery of the component that are generating heat.

The vapor chamber or heat dissipation device of the present invention may be mounted on an electronic device for the purpose of heat dissipation. Accordingly, the present invention provides an electronic device comprising the vapor chamber or heat dissipation device of the present invention. Examples of the electronic device of the present invention include smartphones, tablets, notebook PCs and the like. As described above, the vapor chamber of the present invention operates independently without the need for external power, and can diffuse heat two-dimensionally at high speed by utilizing the latent heat of evaporation and condensation of the working liquid. Therefore, when the electronic device is provided with the vapor chamber or the heat dissipation device of the present invention, heat dissipation can be effectively realized in the limited space inside the electronic device.

(Example 1)
First, two sheets of Cu foil forming the upper housing sheet 6 and the lower housing sheet 7 were prepared. The dimensions of the Cu foil forming the upper housing sheet 6 were 110 mm in length and 60 mm in width, and the thickness was 0.2 mm. The dimensions of the Cu foil forming the lower housing sheet 7 were 110 mm in length and 60 mm in width, and the thickness was 0.08 mm. The pillar 3 was formed by etching on the Cu foil forming the upper housing sheet 6. The etching solution used for forming the column 3 was sodium persulfate, and the etching time was adjusted so that the height of the column 3 was 150 μm. After the pillar 3 was formed, the Cu foil forming the upper housing sheet 6 was heat-treated at 180 ° C. for 30 minutes at atmospheric pressure to form an oxide film on the surface of the Cu foil forming the upper housing sheet 6. The pores 10 were formed by etching on the Cu foil forming the upper housing sheet 6 having an oxide film on the surface. The etching solution used for forming the pores 10 was iron chloride, the etching temperature was 25 ° C., and the etching time was 30 seconds. The wick 4 is arranged so as to be sandwiched between the upper housing sheet 6 and the lower housing sheet 7 in which the pores 10 are formed, and the outer edge portion of the upper housing sheet 6 and the outer edge portion of the lower housing sheet 7 are arranged. Was sealed by laser welding to obtain the vapor chamber body of the present invention. Next, one of the four corners of the obtained vapor chamber main body was cut out, a Cu pipe was inserted therein, and then the vapor chamber main body and the Cu pipe were fixed by soldering. This Cu pipe was connected to a vacuum pump and a syringe containing water, which is the working fluid, via a switching valve. First, the switching valve was connected to the inside of the vapor chamber and the vacuum pump to reduce the pressure inside the vapor chamber body. After that, the valve was switched, the inside of the vapor chamber was connected to the syringe containing the working liquid, a predetermined amount of the working liquid was injected into the inside of the vapor chamber, and then the Cu pipe was crimped and sealed to form a vapor chamber. The thickness of the wick 4 used was 50 μm, and the obtained vapor chamber had a height A of 0.3 mm, a width B of 110 mm, and a depth D of 60 mm.

(Example 2)
The vapor chamber of the present invention was prepared in the same manner as in Example 1 except that the etching solution used for forming the pores 10 was iron chloride, the etching temperature was 25 ° C., and the etching time was 1 minute. Got

(Example 3)
The vapor chamber of the present invention was prepared in the same manner as in Example 1 except that the etching solution used for forming the pores 10 was iron chloride, the etching temperature was 25 ° C., and the etching time was 2 minutes. Got

(Comparative Example 1)
The vapor chamber of the present invention was obtained by the same method as in Example 1 except that the etching step for forming the pores 10 was not performed.

When the SEM image of the cross section of the main inner surface of the upper housing sheet 6 of Examples 1 to 3 was measured, it was as shown in FIGS. 6 to 8. Here, the upper side from the white part in the central part of FIGS. 6 to 8 is a protective film provided later for observation, and the lower side from the white part in the central part of the figure is a cross section of the housing. The main inner surface of the upper housing sheet 6 of Example 1 shown in FIG. 6 had pores 10 having an average depth of 10 nm. The main inner surface of the upper housing sheet 6 of Example 2 shown in FIG. 7 had pores 10 having an average depth of 20 nm. The main inner surface of the upper housing sheet 6 of Example 3 shown in FIG. 8 had pores 10 having an average depth of 40 nm. In FIGS. 6 to 8, some of the pores 10 are surrounded by a broken line circle to indicate the position of the pores 10.

When five vapor chambers of Example 1 were manufactured and subjected to a thermal shock test at 85 ° C. on the high temperature side and −40 ° C. on the low temperature side for 300 cycles, the maximum heat transfer amount was 60 as compared with that before the thermal shock test. The number of those with% or less was 0. When five vapor chambers of Examples 2 and 3 were manufactured and a thermal shock test was conducted in the same manner, the maximum heat transport amount was 60% or less as compared with that before the thermal shock test. It was 0.

On the other hand, when five vapor chambers of Comparative Example 1 were manufactured and a thermal shock test was conducted in the same manner, the maximum heat transport amount of four of the five vapor chambers was the same as before the thermal impact test. It was 60% or less in comparison. It is considered that this is because the vapor chamber of Comparative Example 1 does not have the pores 10 because the etching step for forming the pores 10 is not performed in the manufacturing process of the vapor chamber of Comparative Example 1. .. Since the main inner surface of the housing 2 of the vapor chamber of Comparative Example 1 does not have pores 10, the amount of impurity gas trapped by the wick cannot be reduced, the hydrophilicity of the wick deteriorates, and the vapor It is probable that the heat conduction characteristics of the chamber deteriorated.

In the present specification, the maximum heat transfer amount means that when a 1.5 cm × 1.5 cm ceramic heater is installed in the center of one short side of the vapor chamber and the amount of heat input by this heater is increased. The amount of heat input from the heater when the temperature of the surface of the housing opposite to the surface on which the ceramic heater is installed is 5 ° C or more higher than the temperature of the central part of the vapor chamber.

From this, the vapor chamber of the present invention has pores 10 on the main inner surface of the housing 2, so that the amount of impurity gas trapped by the wick 4 can be reduced, and the hydrophilicity of the wick 4 deteriorates. However, it has been clarified that it is possible to prevent the heat conduction characteristics of the vapor chamber from deteriorating.

The vapor chamber, heat dissipation device and electronic device of the present invention can be used in a wide range of applications in the fields 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.

1a Vapor Chamber 1b Vapor Chamber 1c Vapor Chamber 2 Housing 3 Pillar 4 Wick 5 Convex 6 Upper Housing Sheet 7 Lower Housing Sheet 8 Joining Layer 10 Pore

Claims (12)

With the housing
Pillars arranged in the internal space of the housing so as to support the housing from the inside,
The working fluid enclosed in the internal space of the housing and
It has a wick arranged in the internal space of the housing and has.
At least a part of the main inner surface of the housing is exposed to the internal space of the housing, and has pores having an average depth of 10 nm or more.
At least a part of the pillar exposed to the internal space of the housing has pores having an average depth of 10 nm or more.
The pores are a plurality of pores that are discontinuous with each other.
Vapor chamber. The vapor chamber according to claim 1, wherein the average depth of the pores on the main inner surface of the housing is 40 nm or less. The vapor chamber according to claim 1 or 2, wherein the average diameter of the pores on the main inner surface of the housing is 10 nm or more and 100 nm or less. The vapor chamber according to any one of claims 1 to 3, wherein the average depth of the pores of the pillar is 40 nm or less. The vapor chamber according to any one of claims 1 to 4, wherein the average diameter of the pores of the pillar is 10 nm or more and 100 nm or less. The vapor chamber according to any one of claims 1 to 5 , wherein a convex portion having a height of 1 μm or more and 100 μm or less is formed on the main inner surface facing the main inner surface having the pores. The vapor chamber according to any one of claims 1 to 6 , wherein the housing comprises two opposing sheets whose outer edges are sealed. The vapor chamber according to any one of claims 1 to 7 , wherein the wick is arranged on a main inner surface facing the main inner surface having the pores in at least a part thereof. The vapor chamber according to any one of claims 1 to 8 , wherein the pores are a plurality of independent pores. The vapor chamber according to any one of claims 1 to 9 ^{, wherein the average number of pores provided per 1 μm 2 of} the surface defining the internal space of the housing is 10 or more and 1000 or less. A heat dissipation device comprising the vapor chamber according to any one of claims 1 to 10. An electronic device comprising the vapor chamber according to any one of claims 1 to 10 or the heat dissipation device according to claim 11.

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