Vapor chamber designing method, vapor chamber manufacturing method, and vapor chamber

Abstract

A vapor chamber (1) comprises a flat-plate-shaped housing (50) in which an internal space (20) is formed. The housing (50) has formed therein: a heat reception part (3) that receives heat from a heat source body (2); a steam flow passage (5) through which a coolant (CO) vaporized at the heat reception part (3) travels; and a capillary flow passage (4) through which the coolant (CO) liquefied due to heat dissipation is sent to the heat reception part (3) with a capillary force. A plurality of spacers (42) for reinforcing the housing (50) are arranged in the internal space (20) in the surface direction of the housing (50). The spacing Lsp [mm] between the spacer (42) and a bonding protrusion (17) adjacent to each other is defined to satisfy the expression below, where: δc [mm] is the permissible bending deformation amount for the housing (50); E [N / mm2] is the longitudinal elastic modulus of the housing (50); I [mm2] is the secondary cross-sectional moment of inertia of the housing (50); and w [N / mm] is a uniformly distributed load that is applied per unit length to the housing (50) by an internal pressure generated in the internal space (20) or an external pressure.

Description

Vapor chamber design method, vapor chamber manufacturing method, and vapor chamber

[0001] The present invention relates to a vapor chamber design method, a vapor chamber manufacturing method, and a vapor chamber.

[0002] In a vapor chamber or flat heat pipe (hereinafter simply referred to as a vapor chamber), a type of heat diffusion plate that diffuses heat received from an object to be cooled in a planar direction, a refrigerant sealed in the internal space changes phase upon receiving heat and circulates in the planar and thickness directions to achieve heat transport. The liquefied refrigerant receives heat in the heat receiving section near the object to be cooled and evaporates, then moves in the planar and thickness directions to the condenser section due to the pressure difference in the internal space. The vaporized refrigerant that reaches the condenser section releases heat, condenses, and liquefies. The liquefied refrigerant moves due to the action of capillary forces generated in the internal microchannels and returns to the heat receiving section (see, for example, Patent Document 1).

[0003] Patent No. 4035155

[0004] In electronic components such as semiconductor devices, the input power that is not used to perform work is converted into thermal energy, generating Joule heat. As the temperature of electronic components rises, their operating efficiency decreases and their lifespan shortens. Therefore, if the temperature rise can be suppressed, relatively high operating efficiency and a longer lifespan can be achieved.

[0005] Joule heat is transferred from electronic components to the air or to the mounting board on which the electronic components are mounted. Therefore, the degree of temperature rise of the electronic components themselves depends on the heat transfer efficiency of the mounting board. If the heat transfer efficiency of the mounting board is high, the temperature rise of the electronic components will be small, and conversely, if the heat transfer efficiency of the mounting board is low, the temperature rise of the electronic components will be large. For this reason, it is necessary to use a mounting board with high heat transfer efficiency.

[0006] Metal core substrates made of metals with high thermal conductivity, such as copper, are used as substrates with high thermal conductivity. Copper has a high thermal conductivity as a metal, but it still has a thermal conductivity of 400 W·m －１ K －１The vapor chamber described above has attracted attention as a heat dissipation component with a thermal conductivity higher than that of metals such as copper. This is because the vapor chamber is a latent heat transport component that transports heat by the phase change of a refrigerant sealed inside a container with an airtight structure, and has high thermal diffusivity.

[0007] Furthermore, the process of mounting electronic components on a mounting board includes the reflow process for surface-mounted components. In the reflow process, solder is applied between the contacts of the circuit formed on the board and the contacts of the components, and then the solder is melted in a heating furnace, thereby simultaneously mounting a large number of components to the board. The board on which electronic components are mounted must be heat-resistant enough to not deform even when the temperature of the applied solder reaches or exceeds the melting point of the solder during reflow. However, the heat resistance temperature of a vapor chamber is generally set at around 150°C, which poses a problem with heat resistance during reflow.

[0008] Furthermore, when using a vapor chamber as a mounting substrate, a bonding process is performed in which the vapor chamber and a thin substrate are bonded together by pressing. Therefore, a vapor chamber with low mechanical strength to withstand external stresses such as pressing is difficult to use as a mounting substrate. In the vapor chamber disclosed in Patent Document 1, a reinforcing portion is formed in the internal space to achieve mechanical strength to withstand the increase in internal pressure caused by a temperature rise or the above-mentioned external stress. However, the reinforcing portion is formed only around the refrigerant hole through which the refrigerant is injected.

[0009] In addition to capillary and viscous forces, liquefied refrigerants are also affected by gravity. If the capillary force is not sufficiently greater than gravity, gravity acts as a resistance to the capillary force depending on the installation position of the heat diffusion plate, reducing the thermal performance of the vapor chamber. It is desirable for the vapor chamber to maintain its thermal performance even when the installation position is changed.

[0010] The environment in which the device incorporating the vapor chamber is installed varies, and the resistance forces acting on the liquefied refrigerant also vary depending on the installation environment. For example, if the vapor chamber is installed on a moving object undergoing acceleration, the inertial force due to the acceleration can also act as a resistance force against the capillary force. If the magnitude of the capillary force acting on the fluid mass of the liquefied refrigerant is insufficient to counter these resistance forces, the thermal performance of the vapor chamber will be reduced.

[0011] The present invention has been made in light of the above-mentioned circumstances, and aims to provide a method for designing a vapor chamber, a method for manufacturing a vapor chamber, and a vapor chamber that can suppress deformation due to an increase in internal pressure caused by high heat or deformation due to external forces.

[0012] Furthermore, the present invention has been made in light of the above-mentioned circumstances, and aims to provide a method for designing a vapor chamber, a method for manufacturing a vapor chamber, and a vapor chamber that can perform sustained thermal diffusion of an amount of heat equal to or greater than the amount of heat generated by the object to be cooled, without the thermal performance being affected by resistance.

[0013] In order to achieve the above object, a vapor chamber design method according to a first aspect of the present invention is a vapor chamber design method executed by an information processing device, wherein the vapor chamber has a flat housing having an internal space formed therein, the housing being formed with a heat receiving portion that receives heat from an object to be cooled, a vapor flow path through which refrigerant vaporized in the heat receiving portion moves, and a capillary flow path that sends refrigerant liquefied by heat radiation to the heat receiving portion by capillary force, a plurality of reinforcing members that reinforce the housing in a thickness direction are arranged in the internal space along a surface direction of the housing, and an allowable bending deformation amount of the housing is set to δ ｃ [mm], and the longitudinal elastic modulus of the housing is E [N / mm ２ ] and the second moment of area of ​​the housing is I [mm ２ ], and the uniformly distributed load, which is the load per unit length applied to the housing due to the internal pressure or external pressure generated in the internal space, is w [N / mm], the interval L of the adjacent reinforcing members is ｓｐ [mm] is defined to satisfy the following formula.

[0014] the capillary flow path comprises a first micro-flow path which is a two-dimensional lattice-like flow path formed at a uniform lattice pitch along the surface direction of the vapor chamber, the first micro-flow path comprising a straight pipe section which sends the fluid mass of the refrigerant in one direction, and connecting sections which connect the straight pipe sections together at lattice points of the first micro-flow path, the first condition being that the acceleration caused by the capillary force applied to the fluid mass in the straight pipe section is positive, the second condition being that the acceleration caused by the capillary force applied to the fluid mass in the connecting section is positive, the third condition being that the sum of the work done by the force applied to the fluid mass in the straight pipe section and the work done by the force to which the fluid mass is applied in the connecting section is positive, and the fourth condition being that the total amount of latent heat of evaporation per unit time of the fluid mass returning from the capillary flow path to the heat receiving section exceeds the amount of heat input per unit time from the body to be cooled to the heat receiving section, Materials for the refrigerant and the vapor chamber may be selected and values ​​of design parameters related to the flow path structure of the capillary flow path may be determined so as to satisfy all of the first condition, the second condition, and the fourth condition, or so as to satisfy all of the first condition, the third condition, and the fourth condition.

[0015] A vapor chamber design method according to a second aspect of the present invention is a vapor chamber design method executed by an information processing device, wherein the vapor chamber has a flat casing having an internal space formed therein, and the casing is provided with: a heat receiving portion that receives heat from an object to be cooled; a vapor flow path through which refrigerant vaporized in the heat receiving portion moves; and a capillary flow path that sends refrigerant liquefied by heat radiation to the heat receiving portion by capillary force; the capillary flow path comprises first micro-flow paths that are two-dimensional lattice-like flow paths formed at a uniform lattice pitch along a surface direction of the vapor chamber; the first micro-flow paths comprise: straight pipe portions that send a fluid mass of the refrigerant in one direction; and connecting portions that connect the straight pipe portions to each other at lattice points of the first micro-flow paths; a first condition is that the acceleration caused on the fluid mass by the capillary force applied to the fluid mass in the straight pipe portions is positive; and a second condition is that the acceleration caused on the fluid mass by the capillary force applied to the fluid mass at the connecting portion is positive; The third condition is that the sum of the work done by the force applied to the fluid mass in the straight pipe section and the work done by the force applying the fluid mass at the connecting section is positive, and the fourth condition is that the total amount of evaporation latent heat per unit time of the fluid mass returning from the capillary flow path to the heat receiving section exceeds the amount of heat input per unit time from the body to be cooled to the heat receiving section, and materials for the refrigerant and the casing are selected and values ​​of design parameters related to the flow path structure of the capillary flow path are determined so that either all of the first condition, the second condition, and the fourth condition are satisfied, or all of the first condition, the third condition, and the fourth condition are satisfied.

[0016] In this case, the acceleration generated in the fluid mass by the capillary force in the straight pipe section is a [m / s ２ ], and the density of the fluid mass is ρ [kg / m ３ ], and the volume of the fluid mass is V [m ３ ], and the capillary force in the straight tube portion is f ｃ [N], and the resistance force that prevents the movement of the fluid mass due to the capillary force is F Ｒ When [N] is used, is a conditional expression expressing the first condition, the capillary flow path includes second micro-flow paths extending in the thickness direction of the housing and two-dimensionally arranged at a uniform arrangement pitch in the surface direction of the housing, the connecting portion includes a first connecting portion not connected to the second micro-flow path and a second connecting portion connected to the second micro-flow path, and the acceleration generated in the fluid mass by the capillary force at the first connecting portion is defined as a ｇａｐ [m / s ２ ], and the acceleration generated in the fluid mass by the capillary force at the second connecting portion is a ｇａｐ．ｂｔｍ [m / s ２ ], and the capillary force generated in the first connecting portion is f ｃ．ｇａｐ [N], and the capillary force generated in the second connecting portion is f ｃ．ｇａｐ．ｂｔｍ When [N] is used, is a conditional expression expressing the second condition, and the length of the straight pipe section in the direction in which the fluid mass flows is L ＤＴ [m], the length of the connecting portion in the direction in which the fluid mass flows is 2W [m], and the ratio of the number of the first connecting portions to the number of the connecting portions in which the fluid mass exists is ε, is a conditional expression expressing the third condition, and the amount of heat input per unit time from the object to be cooled in the heat receiving portion is Q ｉｎ [W], and the latent heat of vaporization per unit mass of the fluid mass is Q ＬＨ [J / kg], and the number of the first microchannels in contact with the outer edge of the heat receiving portion is N １．Ｃ The number of the second micro-channels in contact with the heat receiving portion is N ２．Ｐ and i (i=1 to N) in contact with the outer edge of the heat receiving part. １．Ｃ The cross-sectional area of ​​the cross section of the first microchannel (a natural number of which is a positive integer) perpendicular to the direction in which the fluid mass flows is defined as S Ａ１．ｉ [m ２ ], and j (j=1 to N) in contact with the heat receiving portion ２．Ｐ The cross-sectional area of ​​the cross section of the second microchannel (a natural number of which is a positive integer) perpendicular to the direction in which the fluid mass flows is defined as S Ａ２．ｊ [m ２ ], and the velocity of the fluid mass flowing in the ith first microchannel in contact with the outer edge of the heat receiving portion is defined as v １．ｉ[m / s], and the velocity of the fluid mass flowing in the j-th second microchannel in contact with the heat receiving portion is v ２．ｊ When expressed as [m / s], may be a conditional expression expressing the fourth condition.

[0017] The straight pipe portion has a rectangular cross section perpendicular to the direction in which the fluid mass flows, the distance between opposing inner wall surfaces in the thickness direction in the straight pipe portion is 2H [m], the distance between opposing inner wall surfaces in the plane direction in the straight pipe portion is 2W [m], the surface tension of the fluid mass with respect to the inner wall surface is σ [N / m], and the contact angle between the fluid mass and the inner wall surface is θ [rad], then ｃ [N] is The capillary force f generated in the fluid mass at the first connecting portion is defined as ｃ．ｇａｐ [N] is The capillary force f generated in the fluid mass at the second connecting portion is defined as ｃ．ｇａｐ．ｂｔｍ [N] is It may be so defined as follows.

[0018] The length of the fluid mass in the direction in which the fluid mass flows is defined as h [m], and the arrangement pitch of the straight pipe sections in the direction in which the fluid mass flows is defined as L ＤＰ [m], and the shear stress generated on the inner wall surface of the first microchannel along the thickness direction is τ ｗ．ｓｐ [Pa], and the shear stress generated on the inner wall surface of the first microchannel along the surface direction is τ ｗ．ｄｐ When the resistance force F is Ｒ The viscous force f generated in the fluid mass flowing through the first microchannel is included in Ｒ１ [N] is It may be so defined as follows.

[0019] The resistance force that prevents the movement of the fluid mass due to the capillary force may include at least one of gravity, inertial force, and electromagnetic force.

[0020] A method for manufacturing a vapor chamber according to a third aspect of the present invention is a method for manufacturing a vapor chamber, wherein the vapor chamber has a flat housing having an internal space formed therein, the housing being formed with a heat receiving portion that receives heat from an object to be cooled, a vapor flow path through which refrigerant vaporized in the heat receiving portion moves, and a capillary flow path that sends refrigerant liquefied by heat radiation to the heat receiving portion by capillary force, a plurality of reinforcing members that reinforce the housing in a thickness direction are arranged in the internal space along a surface direction of the housing, and an allowable bending deformation amount of the housing is set to δ ｃ [mm], and the longitudinal elastic modulus of the housing is E [N / mm ２ ] and the second moment of area of ​​the housing is I [mm ２ ], and the uniformly distributed load, which is the load per unit length applied to the housing due to the internal pressure or external pressure generated in the internal space, is w [N / mm], the interval L of the adjacent reinforcing members is ｓｐ The reinforcing member is formed in the internal space of the housing so that the distance [mm] satisfies the following formula:

[0021] the capillary flow path comprises a first micro-flow path which is a two-dimensional lattice-like flow path formed at a uniform lattice pitch along the surface direction of the vapor chamber, the first micro-flow path comprising a straight pipe section which sends the fluid mass of the refrigerant in one direction, and connecting sections which connect the straight pipe sections together at lattice points of the first micro-flow path, the first condition being that the acceleration caused by the capillary force applied to the fluid mass in the straight pipe section is positive, the second condition being that the acceleration caused by the capillary force applied to the fluid mass in the connecting section is positive, the third condition being that the sum of the work done by the force applied to the fluid mass in the straight pipe section and the work done by the force to which the fluid mass is applied in the connecting section is positive, and the fourth condition being that the total amount of latent heat of evaporation per unit time of the fluid mass returning from the capillary flow path to the heat receiving section exceeds the amount of heat input per unit time from the body to be cooled to the heat receiving section, It is also possible to select materials for the refrigerant and the casing so as to satisfy all of the first condition, the second condition, and the fourth condition, or so as to satisfy all of the first condition, the third condition, and the fourth condition, and determine values ​​of design parameters related to the flow path structure of the capillary flow path; form the casing, having the flow path structure of the capillary flow path based on the determined values ​​of the design parameters, using the selected material; and seal the selected refrigerant in the internal space of the casing.

[0022] A manufacturing method of a vapor chamber according to a fourth aspect of the present invention is a manufacturing method of a vapor chamber, wherein the vapor chamber has a flat casing having an internal space formed therein, and the casing is provided with: a heat receiving portion that receives heat from an object to be cooled; a vapor flow path through which refrigerant vaporized in the heat receiving portion moves; and a capillary flow path that sends refrigerant liquefied by heat radiation to the heat receiving portion by capillary force; the capillary flow path comprises first micro-flow paths that are two-dimensional lattice-like flow paths formed at a uniform lattice pitch along a surface direction of the vapor chamber; the first micro-flow paths comprise: straight pipe portions that send a fluid mass of the refrigerant in one direction; and connecting portions that connect the straight pipe portions at lattice points of the first micro-flow paths; and a first condition is that the acceleration caused on the fluid mass by the capillary force applied to the fluid mass in the straight pipe portions is positive; and a second condition is that the acceleration caused on the fluid mass by the capillary force applied to the fluid mass at the connecting portion is positive. a third condition being that the sum of the work done by the force applied to the fluid mass in the straight pipe section and the work done by the force applying the fluid mass at the connecting section is positive; and a fourth condition being that the total amount of evaporation latent heat per unit time of the fluid mass returning from the capillary flow path to the heat receiving section exceeds the amount of heat input per unit time from the body to be cooled to the heat receiving section; selecting materials for the refrigerant and the casing and determining values ​​of design parameters related to the flow path structure of the capillary flow path so that either the first condition, the second condition, and the fourth condition are all satisfied, or the first condition, the third condition, and the fourth condition are all satisfied; forming the casing, having the flow path structure of the capillary flow path based on the determined values ​​of the design parameters, from the selected material; and sealing the selected refrigerant in the internal space of the casing.

[0023] A vapor chamber according to a fifth aspect of the present invention has a flat housing in which an internal space is formed, the housing being provided with a heat receiving portion that receives heat from an object to be cooled, a vapor flow path through which refrigerant vaporized at the heat receiving portion moves, and a capillary flow path that sends refrigerant liquefied by heat radiation to the heat receiving portion by capillary force, and a plurality of reinforcing members that reinforce the housing in a thickness direction are arranged in the internal space along a surface direction of the housing, and the allowable bending deformation of the housing is set to δ ｃ [mm], and the longitudinal elastic modulus of the housing is E [N / mm ２ ] and the second moment of area of ​​the housing is I [mm ２ ], and the uniformly distributed load, which is the load per unit length applied to the housing due to the internal pressure or external pressure generated in the internal space, is w [N / mm], the interval L of the adjacent reinforcing members is ｓｐ [mm] is defined to satisfy the following formula:

[0024] the capillary flow path comprises a first micro-flow path which is a two-dimensional lattice-like flow path formed at a uniform lattice pitch along the surface direction of the vapor chamber, the first micro-flow path comprising a straight pipe section which sends the fluid mass of the refrigerant in one direction, and connecting sections which connect the straight pipe sections together at lattice points of the first micro-flow path, the first condition being that the acceleration caused by the capillary force applied to the fluid mass in the straight pipe section is positive, the second condition being that the acceleration caused by the capillary force applied to the fluid mass in the connecting section is positive, the third condition being that the sum of the work done by the force applied to the fluid mass in the straight pipe section and the work done by the force to which the fluid mass is applied in the connecting section is positive, and the fourth condition being that the total amount of latent heat of evaporation per unit time of the fluid mass returning from the capillary flow path to the heat receiving section exceeds the amount of heat input per unit time from the body to be cooled to the heat receiving section, The refrigerant, the material of the vapor chamber, and the flow path structure of the capillary flow path may satisfy all of the first condition, the second condition, and the fourth condition, or may satisfy all of the first condition, the third condition, and the fourth condition.

[0025] a vapor chamber according to a sixth aspect of the present invention, the vapor chamber having a flat casing in which an internal space is formed, the flat casing having a heat receiving portion that receives heat from an object to be cooled, a vapor flow path through which refrigerant vaporized at the heat receiving portion moves, and a capillary flow path that sends refrigerant liquefied by heat radiation to the heat receiving portion by capillary force, the capillary flow path comprising first micro-flow paths that are two-dimensional lattice-like flow paths formed at a uniform lattice pitch along a surface direction of the vapor chamber, the first micro-flow paths comprising straight pipe portions that send a fluid mass of the refrigerant in one direction, and connecting portions that connect the straight pipe portions to each other at lattice points of the first micro-flow paths, the first condition being that the acceleration caused on the fluid mass by the capillary force applied to the fluid mass at the straight pipe portions is positive, and the second condition being that the acceleration caused on the fluid mass by the capillary force applied to the fluid mass at the connecting portion is positive, The third condition is that the sum of the work done by the force applied to the fluid mass in the straight pipe section and the work done by the force applying the fluid mass at the connecting section is positive, and the fourth condition is that the total amount of evaporation latent heat per unit time of the fluid mass returning from the capillary flow path to the heat receiving section exceeds the amount of heat input per unit time from the body to be cooled to the heat receiving section, and the refrigerant, the material of the housing, and the flow path structure of the capillary flow path satisfy all of the first condition, the second condition, and the fourth condition, or satisfy all of the first condition, the third condition, and the fourth condition.

[0026] According to the present invention, deformation due to an increase in internal pressure caused by high heat or deformation due to an external force can be suppressed.

[0027] According to the present invention, in a flow path that generates capillary force in a two-dimensional lattice pattern formed with a uniform lattice pitch, the capillary force applied to the fluid mass of the refrigerant exceeds the resistance force that hinders the movement of the fluid mass, and the work done by the force applied to the fluid mass becomes positive overall, and the materials of the refrigerant and vapor chamber can be selected and the values ​​of the design parameters related to the flow path structure of the capillary flow path can be determined so that dryout does not occur in the heat receiving part, thereby enabling sustained heat diffusion without the thermal performance being affected by the resistance force.

[0028] 1A is a side view of a vapor chamber according to an embodiment of the present invention; FIG. 1C is a perspective view of the vapor chamber of FIG. 1A; FIG. 1C is a side view of a modified vapor chamber according to an embodiment of the present invention; FIG. 1D is a perspective view of a vapor chamber of FIG. 1C; FIG. 1A is a perspective view of a member constituting the heat pipe of FIGS. 1A and 1B; FIG. 1C is a perspective view of a member constituting the heat pipe of FIGS. 1D and 1C; FIG. 1D is a top view of a lower member; FIG. 1C is an enlarged view of a portion of an internal region of the lower member; FIG. 1D is a top view of a modified lower member; FIG. 1D is a top view of an intermediate member; FIG. 1D is an enlarged view of a portion of a capillary channel forming region of the intermediate member; FIG. 1D is a top view of a modified intermediate member; FIG. 1D is a schematic view showing an internal space of a vapor chamber as viewed in the thickness direction and the surface direction; FIG. 1D is a schematic view showing an internal space of a modified vapor chamber as viewed in the thickness direction and the surface direction; FIG. 1D is a diagram showing an example of the arrangement of capillary channels (first microchannels) formed in the lower member; FIG. 1D is a diagram showing an example of the arrangement of capillary channels (first microchannels); FIG. 1D is a diagram showing a capillary channel as viewed from the side; FIG. 1D is a first schematic view showing the structure of the first microchannel; FIG. 1D is a second schematic view showing the structure of the first microchannel. 1B is a first schematic diagram showing a first condition and a second condition. FIG. 1C is a second schematic diagram showing a first condition and a second condition. FIG. 1D is a schematic diagram showing a third condition. FIG. 1E is a first schematic diagram showing the inflow of heat and the movement of a refrigerant in a heat receiving section. FIG. 1F is a second schematic diagram showing the inflow of heat and the movement of a refrigerant in a heat receiving section. FIG. 1G is a block diagram showing the hardware configuration of an information processing device that performs design processing. FIG. 1H is a flowchart of the design processing. FIG. 1I is a top view of a lighting device that includes the vapor chamber of FIG. 1A as a mounting board. FIG. 1I is an exploded perspective view of some structures on the mounting surface of the mounting board in the lighting device. FIG. 1J is a cross-sectional view showing the connection state of one LED on the mounting board. FIG. 1I is a graph comparing the junction temperatures of the LED elements in the vapor chamber of FIG. 1A and on a copper substrate. FIG. 1J is a side view showing a state in which the vapor chamber is installed in a first orientation. FIG. 1J is a side view showing a state in which the vapor chamber is installed in a second orientation. FIG. 1J is a side view showing a state in which the vapor chamber is installed in a third orientation. FIG. 1J is a graph showing the comparison results of thermal resistance when the orientation of the vapor chamber is changed.

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same or equivalent parts are designated by the same reference numerals.

[0030] [Embodiment 1] First, embodiment 1 of the present invention will be described. As shown in FIGS. 1A and 1B, a vapor chamber 1 serving as a heat diffusion plate according to this embodiment is a cooling device having a generally flat, specifically, disk-shaped housing 50 with its thickness oriented in the z-axis direction. The shape of the housing 50 is not limited to a disk shape and may be, for example, a rectangular flat plate as shown in FIGS. 1C and 1D. Hereinafter, whether the shape shown in FIGS. 1A and 1B or the shape shown in FIGS. 1C and 1D is referred to as vapor chamber 1, and components having the same function will be described with the same reference numerals. The housing 50 is made of a material capable of forming an airtight structure. An example of such a material is copper. A disk-shaped heat source 2, which serves as the object to be cooled, is attached to the center of the bottom surface of the vapor chamber 1 facing the -z direction. The shape of the heat source 2 is not limited to a disk shape and may be, for example, rectangular.

[0031] The heat source 2 may be an IC (semiconductor integrated circuit), an LSI (large scale integrated circuit), a CPU (central processing unit), an LED (light emitting diode), etc. In the vapor chamber 1, the center of the bottom surface to which the heat source 2 is attached is called the heat receiving section 3, which receives heat from the heat source 2. The heat received by the heat receiving section 3 from the heat source 2 is transferred to the entire vapor chamber 1 and dissipated.

[0032] As shown in FIG. 1A , a depressurized sealed space (internal space) 20 is provided within the housing 50 of the vapor chamber 1. Refrigerant CO is sealed in the internal space 20. Due to the heat received by the heat receiving portion 3, the liquefied refrigerant CO vaporizes and diffuses throughout the internal space 20. The diffused refrigerant CO transfers heat to the outer surface of the vapor chamber 1, then condenses and becomes liquefied refrigerant CO, which returns to the heat receiving portion 3 by capillary force. The heat transferred to the outer surface of the vapor chamber 1 is dissipated to the outside. In this way, the vapor chamber 1 diffuses heat throughout the entire space due to the circulation of the refrigerant CO within the internal space 20.

[0033] 2A and 2B, the vapor chamber 1 includes a lower member 10, an upper member 11, and an intermediate member 12. The lower member 10 is a disk-shaped member. The lower surface (-z surface) of the lower member 10 forms the lower surface of the housing 50 of the vapor chamber 1. The heat receiving portion 3 is provided on the lower surface of the lower member 10.

[0034] 3A and 3C, the upper surface (+z surface) of the lower member 10 is provided with a frame-shaped outer edge portion 10a along its outer edge, and an inner region 10b inside the outer edge portion 10a. The outer edge portion 10a is provided with a bonding protrusion that protrudes upward (toward the +z side) beyond the inner region 10b. The lower member 10 is diffusion bonded to the outer edge of the lower surface of the intermediate member 12 at the outer edge portion 10a.

[0035] The internal region 10b of the lower member 10 forms the bottom surface of the internal space 20. As shown in FIG. 3B , the internal region 10b is formed with a large number of dimples 10c, which are rectangular protrusions with four sides aligned along the x-axis and y-axis directions when viewed in the z-axis direction. The dimples 10c are two-dimensionally arranged at a predetermined pitch in the x-axis and y-axis directions. Grooves 10d extending in the x-axis and y-axis directions are formed between the dimples 10c. These grooves 10d form capillary channels 4 (see FIG. 5 ) through which the liquefied refrigerant CO passes.

[0036] As shown in FIGS. 3A, 3C, and 3B, a plurality of cylindrical joining projections 40 are formed in the surface direction in the inner region 10b of the lower member 10.

[0037] The upper member 11 is a rectangular, flat member having the same shape and size as the lower member 10 shown in FIGS. 2A and 2B. The lower surface (-z side surface) of this upper member 11 forms the ceiling of the internal space 20 of the vapor chamber 1. The lower surface (-z side) of the upper member 11 also has an outer edge portion 10a and an internal region 10b. The internal region 10b is formed with a two-dimensional array of dimples 10c arranged at a predetermined pitch in the x-axis and y-axis directions, and two-dimensional lattice-like grooves 10d extending in the x-axis and y-axis directions. Furthermore, a plurality of cylindrical joining protrusions 40 are formed in the internal region 10b of the upper member 11 at positions facing the joining protrusions 40 of the lower member 10.

[0038] 4A and 4C, the intermediate member 12 has a rectangular frame-shaped outer edge portion 12a provided along its outer edge, and an inner region 12b inside the outer edge portion 12a. The outer edge portion 12a is diffusion-bonded to the outer edge portion 10a of the lower member 10 by diffusion bonding on its lower surface side, and to the outer edge portion 10a of the upper member 11 by diffusion bonding on its upper surface side.

[0039] 4A and 4C , the internal region 12b is divided into capillary channel forming regions 15 and vapor channel forming regions 16. The capillary channel forming regions 15 are disposed in the center of the internal region 12b, and a plurality of capillary channel forming regions 15 extend radially from the center toward the periphery of the internal region 12b, i.e., the outer edge 12a. The vapor channel forming regions 16 are disposed between the radially extending capillary channel forming regions 15. The capillary channel forming regions 15 and the vapor channel forming regions 16 are alternately arranged along the circumferential direction of a circle centered at the center of the internal region 12b.

[0040] Between the capillary channel forming region 15 and the vapor channel forming region 16 and inside the capillary channel forming region 15, there are formed joining protrusions 17 for joining the lower member 10 and the upper member 11. These joining protrusions 17 enable the vapor chamber 1 to have the strength to withstand the increase in internal pressure caused by heat received from the heat source 2 or an increase in internal temperature due to an increase in environmental temperature, or the strength to withstand the increase in external pressure due to an external force. Furthermore, these joining protrusions 17 can separate the capillary channel forming region 15 and the vapor channel forming region 16.

[0041] 4B, a plurality of rectangular through-holes 12c constituting the capillary flow paths are two-dimensionally arranged at a predetermined pitch in the x-axis and y-axis directions in the capillary flow path forming region 15. As shown in FIGS. 4A and 4C, in the vapor flow path forming region 16, the plate is hollowed out to form a void larger than that in the capillary flow path forming region 15.

[0042] 4A and 4C , a plurality of cylindrical bonding protrusions 41 are formed in the surface direction in the capillary flow path forming region 15. The bonding protrusions 41 are formed at positions where they come into contact with the bonding protrusions 40 of the lower member 10 and the upper member 11. Note that, in the lower member 10 and the upper member 11, the bonding protrusions 40 provided at positions corresponding to the vapor flow path forming region 16 of the intermediate member 12 are formed to be higher than the bonding protrusions 40 provided at positions corresponding to the capillary flow path forming region 15.

[0043] 2A and 2B , the lower member 10, the intermediate member 12, and the upper member 11 are joined in this order along the z-axis direction to form the housing 50 of the vapor chamber 1, as shown in FIGS. 5A and 5B . In this case, in the capillary flow path forming region 15 of the intermediate member 12, the joining protrusions 40 of the lower member 10 and the joining protrusions 41 of the intermediate member 12 are diffusion-bonded by pressing, and the joining protrusions 40 of the lower member 10 and the joining protrusions 41 of the intermediate member 12 are diffusion-bonded by pressing, thereby forming a spacer 42. At this time, the spacer 42 is formed without any gaps between the lower member 10 and the intermediate member 12 and between the upper member 11 and the intermediate member 12. In addition, in the vapor flow path forming region 16 of the intermediate member 12, the joining protrusions 40 of the lower member 10 and the joining protrusions 40 of the upper member 11 are diffusion-bonded to form the spacer 42. The spacers 42 are formed for the purpose of reinforcing the housing 50 in the thickness direction so that the internal space 20 does not collapse or expand, and a plurality of spacers 42 are formed in the surface direction of the housing 50. In this embodiment, the spacers 42 and the joining protrusions 17 correspond to the reinforcing members.

[0044] [Reinforcing Member] Here, consider the case where the vapor chamber 1 is used as a mounting substrate for mounting electronic components. In order to achieve appropriate heat transfer efficiency in the vapor chamber 1, it is necessary to appropriately set the value of the Biot number, defined by the following formula: Here, Bi[-] is the Biot number, which is a dimensionless number that represents the ratio of the heat transfer resistance inside the housing 50 to the heat transfer resistance when heat is radiated from the housing 50 to the outside of the system. －２ K －１] is the heat transfer coefficient when heat is dissipated from the housing 50 to the outside of the system. L [m] is the characteristic length related to the size of the housing 50, and k [W m －１ ・K －１ ] is the thermal conductivity of the housing 50. When the heat transfer path when heat is dissipated from the housing 50 to the outside of the system is made up of multiple members, an overall heat transfer coefficient may be used as the heat transfer coefficient as appropriate.

[0045] When the Biot number Bi[-] is large, the temperature unevenness within the surface of the housing 50 becomes large, and conversely, when the Biot number Bi[-] is small, the temperature unevenness within the surface of the housing 50 becomes small. When the temperature unevenness within the surface of the housing 50 is large, the thermal stress generated within the surface becomes uneven. The reason why the thermal stress generated within the surface becomes uneven is because the amount of deformation due to thermal expansion is uneven within the surface of the housing 50.

[0046] If the amount of deformation within the surface of the housing 50 becomes uneven, the distribution of external forces such as shear stress and tensile stress acting on the wiring pattern, etc., will also become uneven, and if this continues to act repeatedly as the amount of heat generated increases and decreases, there is a risk of circuit components being destroyed, so it is necessary to suppress temperature unevenness within the surface of the housing 50. In order to suppress temperature unevenness within the surface of the housing 50 to an appropriate value, it is necessary to reduce the value of the Biot number Bi[-]. From the above formula (1), to reduce the Biot number Bi[-], the heat transfer coefficient when heat is dissipated outside the system or the housing 50 can be reduced, or the thermal conductivity of the housing 50 can be increased.

[0047] Now, the size of the housing 50 is determined by the mounting area required for the components mounted on the housing 50. The mounting area required for the components mounted on the housing 50 is determined by determining the function of the housing 50 and the components required to achieve that function. In other words, it is not possible to reduce the size of the board in order to reduce the Biot number Bi[-] while maintaining the function of the housing 50.

[0048] On the other hand, the amount of heat generated from the housing 50 is Q ｏｕｔ [W], the following equation is obtained from Newton's law of cooling: Here, A ｓ [m ２ ] is the substrate surface area, and U ｓ [W m －２ ・K－１ ] is the overall heat transfer coefficient based on the back surface area when heat is dissipated to the outside of the system from the surface of the housing 50 opposite to the component mounting surface (hereinafter referred to as the back surface of the housing 50), and T ｓ [K] is the back surface temperature, T ａ [K] is the ambient temperature.

[0049] Here, U ｓ , the surface average value of the housing 50<U ｓ Using >, equation (2) is transformed into the following: Therefore, the following formula is derived: Here, <T ｓ > [K] is the average temperature on the back surface.

[0050] Here, Q ｏｕｔ is determined by the power input to the components mounted in the housing 50 and their operating efficiency. Therefore, while the housing 50 is performing the desired operation, the overall heat transfer coefficient h [W m －２ K －１ ], the rear surface temperature of the housing 50 rises. If the rear surface temperature of the housing 50 rises, the temperature of the components mounted therein will also rise, which will result in a decrease in operating efficiency and a shortened lifespan. Therefore, it is inappropriate to reduce the overall heat transfer coefficient h in order to reduce the Biot number Bi[-]. In other words, the only option to reduce temperature unevenness within the surface of the housing 50 when a device of a given size is performing its specified function is to increase the thermal conductivity of the device.

[0051] The vapor chamber 1 according to this embodiment serves as a heat diffusion plate with a higher thermal conductivity than a copper plate. The vapor chamber 1 is heat-resistant to high-temperature processes such as surface mounting by reflow soldering of electronic components, and can suppress temperature variations within the surface of the housing 50, which can lead to reliability problems in electronic component mounting. Furthermore, the vapor chamber 1 can suppress changes in thermal performance due to installation position and suppress uneven temperature distribution of the refrigerant CO.

[0052] The vapor chamber 1 according to this embodiment has heat resistance against high-temperature processes such as surface mounting. Specifically, the vapor chamber 1 is designed so that the bending deformation amount δmax [mm] of the housing 50 satisfies the following relationship: where δ ｃ [mm] is the allowable bending deformation on the surface of the vapor chamber 1.

[0053] Spacers 42 are provided inside the vapor chamber 1 to suppress deformation due to internal pressure or external force. Here, the maximum distance between adjacent spacers 42 provided inside the vapor chamber 1 is defined as L ｓｐ．ｍａｘ [mm], δ ｍａｘ is given by the following formula: Here, w [N / mm] is the uniformly distributed load due to the increase in internal pressure or the increase in external pressure. ２ ] is the modulus of longitudinal elasticity of the material forming the housing 50 of the vapor chamber 1. ４ ] is the second moment of area of ​​the housing 50.

[0054] In the case of an increase in internal pressure, the value of the uniformly distributed load w [N / mm] is ｖｃ The saturated vapor pressure of the refrigerant at [K] P ｓ．ｖｃ It is calculated from [Pa]. ｓ．ｖｃ [Pa] can be calculated, for example, using the Antoine equation for the refrigerant. Furthermore, when the refrigerant CO is a mixed substance, it can be calculated, for example, using the Wilson equation. Various external forces are expected to cause an increase in external pressure. For example, the uniformly distributed load w [N / mm] can be estimated based on the magnitude of the force pressing the vapor chamber 1 in a process of forming electronic components using the vapor chamber 1 as a mounting substrate. For example, the uniformly distributed load w [N / mm] can be estimated based on the pressing force of a press machine pressing the vapor chamber 1 in a process of bonding the vapor chamber 1 to an insulating substrate.

[0055] As a result, the distance L between the adjacent spacers 42 and the joining projections 17 in the vapor chamber 1 of this embodiment is ｓｐ [mm] is subject to the condition that the following formula is satisfied. The right side of the above formula (6) is the maximum interval L ｓｐ．ｍａｘ As shown in FIGS. 5A and 5B, the distance between the joining projections 17 is L [mm]. ｓｐ．ｍａｘ By providing the spacer 42 in the portion where the gap is equal to or greater than [mm], the above formula (6) is satisfied in the vapor chamber 1.

[0056] From the above formula (6), L ｓｐ The smaller the [mm], the smaller the maximum deformation amount, but since the spacer 42 is a part that is joined in the thickness direction, the refrigerant CO cannot flow in that part. Therefore, in the vapor chamber 1 according to this embodiment, the capillary flow path 4 is designed to satisfy conditions 1 to 4 for realizing an appropriate amount of refrigerant circulation.

[0057] An internal space 20 is formed in the housing 50, and a heat receiving portion 3 is provided at the portion joining the heat source 2. A capillary flow path 4 and a vapor flow path 5 are formed in this internal space 20, and the refrigerant CO is sealed in. When not receiving heat, the refrigerant CO coexists in a state of equilibrium, with part of it as a liquid in the capillary flow path 4 including the heat receiving portion 3 and the rest as a gas in the vapor flow path 5, depending on the saturated vapor pressure of the refrigerant CO at the temperature at which the vapor chamber 1 is installed.

[0058] When the heat receiving unit 3 receives heat from the heat source 2, the refrigerant CO vaporizes. The vapor flow path 5 moves the vaporized refrigerant CO in the heat receiving unit 3 toward the outer edge when viewed in the z-axis direction. The vaporized refrigerant CO that has been sent releases heat to the housing 50, gradually condenses, and liquefies, and enters the capillary flow path 4. The capillary flow path 4 sends the liquefied refrigerant CO due to heat release to the heat receiving unit 3 by capillary force.

[0059] As shown in FIG. 6A, the widths of the dimple 10c in the x-axis direction and the y-axis direction on the internal region 10b of the lower member 10 are L ＤＴThe width of the groove 10d is 2W [m]. The grooves 10d are arranged at a lattice pitch P1 [m] in the x-axis direction and the y-axis direction. The microchannels formed by the grooves 10d are the first microchannels 31. The first microchannels 31 are two-dimensional lattice-like channels formed at a uniform lattice pitch P1 along the surface direction of the vapor chamber 1.

[0060] As shown in Figure 6B, the width of the through holes 12c in the intermediate member 12 in the x-axis and y-axis directions is 2W, and they are arranged at an arrangement pitch P2 [m] in the x-axis and y-axis directions. The through holes 12c are arranged at lattice points where the lines in the x-axis and y-axis directions of the grooves 10d in the lower member 10 and the upper member 11 intersect. In Figure 6B, the arrangement pitch P2 of the through holes 12c in the x-axis and y-axis directions is twice the lattice pitch P1 of the lattice points of the grooves 10d, but this is not limited to this. In this embodiment, the lattice pitch P1 and the arrangement pitch P2 can be adjusted using the design method according to this embodiment.

[0061] As shown in Fig. 6C, the height of the dimple 10c is 2H. The depth of the through hole 12c is L ＤＴ The depth of the through-holes 12c is the same as the thickness of the intermediate member 12 and can be changed to any value. The grooves 10d of the lower member 10 and the upper member 11 communicate with the through-holes 12c of the intermediate member 12 to form microchannels that extend in the thickness direction of the vapor chamber 1 and are two-dimensionally arranged at an arrangement pitch P2 along the surface direction of the vapor chamber 1, i.e., the x-axis direction and the y-axis direction. These microchannels are the second microchannels 32. That is, the capillary channel 4 includes the second microchannels 32.

[0062] As shown in FIG. 7A , the first microchannel 31 includes a straight pipe section 31A and a connecting section 31B. The straight pipe section 31A is a tubular section extending in the x-axis direction or the y-axis direction and transporting a fluid mass of refrigerant CO (hereinafter simply referred to as fluid mass CA) in one direction. The straight pipe section 31A has four inner wall surfaces forming a rectangular cross section perpendicular to the flow direction of the fluid mass of liquefied refrigerant CO (hereinafter simply referred to as fluid mass CA), and these inner wall surfaces generate capillary force. The connecting sections 31B are arranged at lattice points of the first microchannel 31 and connect the straight pipe sections 31A to each other at the lattice points. The first microchannel 31 is configured by alternatingly arranging the straight pipe sections 31A and the connecting sections 31B along the x-axis direction and the y-axis direction.

[0063] As shown in Fig. 7B, the second microchannels 32 are arranged at an arrangement pitch P2 and are connected to the connection portions 31B of the first microchannels 31. As shown in Fig. 7B, the connection portions 31B include a first connection portion 31B-1 that is not connected to the second microchannels 32, and a second connection portion 31B-2 that is connected to the second microchannels 32. In this embodiment, the arrangement pitch P2 of the second microchannels 32 is twice the lattice pitch P1 of the connection portions 31B, so that one of every two consecutive second microchannels is a second connection portion 31B-2.

[0064] In the design method according to the present embodiment, the capillary flow path 4 of the vapor chamber 1 having the above-described configuration is designed. In this design method, a first condition, a second condition, a third condition, and a fourth condition are defined as conditions that the capillary flow path 4 must satisfy. The first condition is that the capillary force f ｃ The second condition is that the acceleration a generated in the fluid mass CA by the force [N] is positive (see FIGS. 8A and 8B). ｃ Acceleration a generated in the fluid mass CA by [N] ｇａｐ , a ｇａｐ．ｂｔｍis positive. The third condition is that in the first microchannel 31, the sum of the work done by the force applied to the fluid mass CA in the straight pipe portion 31A and the work done by the force applied to the fluid mass CA in the connecting portion 31B is positive (see FIG. 9). The fourth condition is that the total amount of latent heat of evaporation per unit time of the fluid mass CA returning from the capillary channel 4 to the heat receiving portion 3 exceeds the amount of heat input per unit time from the heat source 2 to the heat receiving portion 3 (see FIGS. 10A and 10B). The first to fourth conditions will be described in detail below.

[0065] [First Condition] The first condition is that the capillary force f applied to the fluid mass CA in the straight pipe portion 31A is ｃ 8A and 8B, in the capillary flow path 4, the capillary force generated in the straight pipe portion 31A is f ｃ [N], and the capillary force f ｃ The resistance force that prevents the movement of the fluid mass CA by [N] is F Ｒ If [N], the following formula is required to be satisfied: For example, in the first microchannel 31, the density of the continuously moving fluid mass CA shown in FIGS. 8A and 8B is ρ [kg / m ３ ], and the volume of the fluid mass CA is V [m ３ In addition, the capillary force f ｃ [N], the acceleration generated in the fluid mass CA is a [m / s ２ ], the equation of motion that satisfies the first condition for the fluid mass CA as a whole is given by the following equation. From the above formulas (7) and (8), the following formula is obtained. The first microchannel 31 extending in the surface direction of the vapor chamber 1 is characterized in that the fluid mass CA moving inside it satisfies formula (9). Formula (9) is a conditional formula representing the first condition. By satisfying this conditional formula, the fluid mass CA can move through the straight pipe section 31A.

[0066] In addition, the resistance force F Ｒ [N] is the various resistance forces acting on the refrigerant CO Ｒｉ [N] and is given by the following formula: n is a positive integer, and the expected resistance force F Ｒ [N] represents the number of types. Resistance F Ｒ [N] is the viscous force f generated by the inner wall surface of the flow path. Ｒ１ [N]. When the refrigerant CO moves vertically upward on Earth, gravity f Ｒ２ [N] also has resistance F Ｒ In addition, when the vapor chamber 1 is in an accelerated motion, the inertial force f generated by the accelerated motion is included in [N]. Ｒ３ [N] also has resistance F Ｒ When the refrigerant CO is an electromagnetic fluid and the vapor chamber 1 is placed in a magnetic field, the electromagnetic force (Lorentz force) generated in the electromagnetic fluid is also included in the resistance force F Ｒ That is, the resistance force F that prevents the movement of the fluid mass CA due to the capillary force is included in [N]. Ｒ [N] is the viscous force f Ｒ１、 gravity f Ｒ２ [N], inertia force f Ｒ３ [N] and electromagnetic force.

[0067] [Capillary force f ｃ 8A and 8B , when the straight pipe portion 31A has a rectangular cross section perpendicular to the flow direction of the fluid mass CA, the distance between the inner wall surfaces facing each other in the thickness direction of the straight pipe portion 31A is 2H [m], the distance between the inner wall surfaces facing each other in the surface direction of the vapor chamber 1 is 2W [m], the surface tension of the fluid mass CA with respect to the inner wall surface is σ [N / m], and the contact angle between the fluid mass CA and the inner wall surface is θ [rad], the capillary force f ｃ [N] is defined by the following formula:

[0068] [Viscous force f Ｒ１ ] On the other hand, f Ｒ１ Let [N] be the viscous force generated by the shear stress received from the inner wall surface due to the movement of the fluid mass CA. In this case, let h [m] be the length of the fluid mass CA in the direction in which the first microchannel 31 extends, and let L be the length of the straight pipe section 31A in the direction in which the fluid mass CAg flows. ＤＴ The arrangement pitch of the straight pipe sections 31A in the direction in which the fluid mass CA flows is L ＤＰThe shear stress generated on the inner wall surface (see FIG. 8A) along the thickness direction of the vapor chamber 1 is defined as τ ｗ．ｓｐ [Pa], and the shear stress generated on the inner wall surface (see FIG. 8B) along the surface direction of the vapor chamber 1 is τ ｗ．ｄｐ Let [Pa]. Also, let ε be the ratio of the number of first connecting portions 31B-1 that are not connected to the second micro-channel 32 to the number of connecting portions 31B where the fluid mass CA exists. ε is 0 when all connecting portions 31B are connected to the second micro-channel, and 1 when all connecting portions 31B are not connected to the second micro-channel.

[0069] The viscous force generated in the entire fluid mass CA is f Ｒ１ [N], then f Ｒ１ [N] is expressed by the following formula: Although h can be set to any value, the worst case scenario is that it is set to the maximum length from the heat receiving portion 3 to the outer edge of the internal space 20 .

[0070] If the resistance force F acting on the fluid mass CA is Ｒ [N] is the viscous force f Ｒ１ If only [N] is used, then the first condition that the first microchannel 31 must satisfy, Equation (9), is transformed as follows:

[0071] [Gravity f Ｒ２ In addition, when the direction of movement of the fluid mass CA on the Earth is not horizontal, the gravity f Ｒ２ [N] will have an effect. Among them, gravity f Ｒ２ The direction of [N] opposes the movement of the fluid mass CA and its effect is greatest when the fluid mass CA is moving vertically upward. In this case, the condition that the first microchannel 31 must satisfy to move the fluid mass CA vertically upward and realize the circulation of the refrigerant CO is expressed by the following equation:

[0072] If the device in which the vapor chamber 1 is installed is subjected to acceleration a ｖｃ [m / s ２ ], the resistance force F acting on the fluid mass CA Ｒ [N] is the inertial force fＲ３ It is necessary to include [N]. Inertial force f Ｒ３ The force [N] becomes maximum when the direction of movement of the fluid mass CA is accelerating as a whole of the vapor chamber 1. Therefore, the force of gravity f Ｒ２ [N] and inertial force f Ｒ３ When [N] occurs, the first condition that the first minute channel 31 must satisfy to achieve circulation of the refrigerant CO is expressed as follows: Similarly, in the above equation, the resistance force F Ｒ [N] is the electromagnetic force f Ｒ４ It is also possible to add [N].

[0073] [Second Condition] The second condition is that the capillary force f applied to the fluid mass CA at the connecting portion 31B is ｃ．ｇａｐ [N] is the viscous force f that prevents the movement of the fluid mass CA. Ｒ１ [N], gravity f Ｒ２ [N], inertia force f Ｒ３ [N] and electromagnetic force f Ｒ４ Resistance force F including at least one of [N] Ｒ In the fluid mass CA shown in Figures 8A and 8B, capillary force occurs not only in the straight pipe portion 31A but also in the connecting portion 31B. As described above, the connecting portion 31B includes a first connecting portion 31B-1 that is not connected to the second micro-channel 32, and a second connecting portion 31B-2 that is connected to the second micro-channel 32. In the connecting portion 31B, there are no inner wall surfaces on both sides in the surface direction, but in the first connecting portion 31B-1 that is not connected to the second micro-channel 32, there is an inner wall surface in the thickness direction. In this case, the capillary force f ｃ．ｇａｐ When [N] is set, f ｃ．ｇａｐ [N] is as follows: Assuming that the fluid mass CA is moving in the horizontal direction, the capillary force f ｃ．ｇａｐ The acceleration generated in the fluid mass CA by [N] is a ｇａｐ [m / s ２ ], the second condition that must be satisfied in the first connecting portion 31B-1 that is not connected to the second microchannel 32 is expressed by the following formula. gravity f Ｒ２Taking into consideration [N], the condition to be satisfied in the first connecting portion 31B-1 is converted into the following equation. inertia force f Ｒ３ When [N] is taken into consideration, equation (3) is transformed into the following equation: Similarly, in the above equation, the electromagnetic force f Ｒ４ It is also possible to add [N].

[0074] In addition, the capillary force generated in the second connecting portion 31B-2 connected to the second microchannel 32 is f ｃ．ｇａｐ.ｂｔｍ When [N] is set, f ｃ．ｇａｐ.ｂｔｍ [N] is as follows:

[0075] Let us assume that the fluid mass CA is moving in the horizontal direction. Let the acceleration generated in the fluid mass CA by the capillary force at the second connecting portion 31B-2 be a ｇａｐ．ｂｔｍ [m / s ２ ], the conditional expression that is the second condition that the second connecting portion 31B-2 must satisfy is given by the following expression.

[0076] gravity f Ｒ２ Taking into consideration [N] as well, the conditional expression as the second condition that the second connecting portion 31B-2 must satisfy is as follows: inertia force f Ｒ３ Taking into consideration [N], the conditional expression of the second condition is as follows: Similarly, in the above equation, the electromagnetic force f Ｒ４ It is also possible to add

[0077] [Third Condition] The third condition is that the sum of the work applied to the fluid mass CA in the straight pipe portion 31A and the work applied to the fluid mass CA by the connecting portion 31B must be positive. For the vapor chamber 1 to function, it is necessary for the fluid mass CA to pass through the connecting portion 31B without coming to a standstill. If equations (16) to (19) and equations (20) to (23), i.e., the second condition, are satisfied, the fluid mass CA will also undergo positive accelerated motion in the flow direction at the connecting portion 31B, and therefore the fluid mass CA will be able to pass through the connecting portion 31B.

[0078] However, even if the second condition is not satisfied, the refrigerant CO can pass through the connecting portion 31B if, when it passes through the connecting portion 31B and again approaches the inner wall surface of the partially continuous straight pipe portion 31A, it has a speed of 0 or greater in approximately the same direction as the original traveling direction of the refrigerant CO. The condition for having this speed is that the refrigerant CO can pass through the connecting portion 31B if the sum of the work received by the fluid mass CA in the straight pipe portion 31A and the work received by the fluid mass CA in the connecting portion 31B is positive, that is, if the sum is positive work with respect to the traveling direction of the refrigerant CO. This is the third condition, and the third condition is given by the following equation. The above equation represents the work done by the force applied to the fluid mass CA from P1 to P2 shown in Fig. 9, i.e., the straight pipe section 31A, and the second term on the left side represents the work done by the force applied to the fluid mass CA from P2 to P3 shown in Fig. 9 (the length 2W of the connecting section 31B in the direction in which the fluid mass CA flows), i.e., the connecting section 31B. Equation (24) shows that the sum of these works is positive.

[0079] [Fourth Condition] The fourth condition is the latent heat of vaporization Q per unit time of the fluid mass CA returning from the capillary flow path 4 to the heat receiving portion 3. ＬＨ The total amount of [J / kg] is the heat input Q per unit time from the heat source 2 to the heat receiving part 3. ｉｎ In the vapor chamber 1, the latent heat of vaporization Q of the refrigerant CO corresponding to the amount of the refrigerant CO returning to the heat source 2 per unit time in the series of cycles of the refrigerant CO is ＬＨ The total amount of heat generated from the heat source 2 is Q ｉｎ By exceeding [W], it becomes possible to continuously supply the amount of refrigerant CO necessary to maintain continuous evaporation to the heat receiving part 3 inside the surface that contacts the heat source 2. Conversely, if it becomes impossible to supply the amount of refrigerant CO necessary to maintain continuous evaporation of the refrigerant CO to the heat receiving part 3, a phenomenon known as dryout occurs. When dryout occurs, continuous latent heat transport by the refrigerant CO becomes impossible, the thermal performance of the vapor chamber 1 decreases, and as a result, the thermal resistance of the vapor chamber 1 increases.

[0080] Here, the amount of heat input per unit time from the heat source 2 to the heat receiving section 3 is Qｉｎ [W], and the latent heat of vaporization per unit mass of the refrigerant CO fluid mass CA is Q ＬＨ 10A and 10B, the curve that forms the outer edge of the heat receiving portion 3 is taken as a circle C. The first minute flow path 31 that faces the circle C is taken as N １．Ｃ Let i (i = 1 to N １．Ｃ The cross-sectional area of ​​the cross section perpendicular to the direction in which the fluid mass CA flows in the )-th first microchannel 31 is defined as S Ａ１．ｉ [m ２ ], and the speed at which the fluid mass CA flows through the i-th first microchannel 31 is v １．ｉ The number of the second minute channels 32 in contact with the heat receiving portion 3 is N ２．Ｐ Let j (j=1 to N ２．Ｐ The cross-sectional area of ​​the second minute channel 32 perpendicular to the direction in which the refrigerant CO flows is S Ａ２．ｊ [m ２ ], and the traveling speed of the fluid mass CA flowing through the j-th second microchannel 32 and returning to the heat receiving section 3 is v ２．ｊ In order for the vapor chamber 1 to not dry out and to continue to exhibit the desired performance, the following relational expression must be satisfied:

[0081] In the design method of the vapor chamber 1 of this embodiment, the type of refrigerant CO and the material of the vapor chamber 1 are selected so as to satisfy all of the first, second, and fourth conditions, or all of the first, third, and fourth conditions, and the values ​​of design parameters related to the flow path structure of the capillary flow path 4 are determined. Such design parameters include the length of the capillary flow path 4 and parameters that define the cross section perpendicular to the direction in which the refrigerant CO flows. As a result, the viscous force f Ｒ１ [N], gravity f Ｒ２ Resistance force F such as [N] ＲEven when the pressure acting as a resistive force to the flow of the refrigerant CO acts as a resistive force to the flow of the refrigerant CO, the circulation of the refrigerant CO can be realized. Furthermore, in order to alleviate non-uniformity of the refrigerant distribution, in the first microchannel 31 having a structure in which at least one of the inner wall surfaces is discontinuous, the refrigerant CO can pass through without stopping at the connecting portion 31B where the inner wall surface is not continuous. Furthermore, in the heat receiving portion 3, it is possible to have a microchannel structure that allows continuous transport from the heat receiving portion 3 to the condensing portion without causing dryout.

[0082] The operation of the vapor chamber 1 having the above configuration will be described. As shown in Figures 4A and 4C, heat emitted from the heat source 2 is transferred to the heat receiving portion 3, and this heat causes the refrigerant CO present in the heat receiving portion 3 to vaporize. The vaporized refrigerant CO passes through the vapor flow path 5 and diffuses throughout the internal space 20. Most of the vaporized refrigerant CO then reaches the outer edge of the internal space 20, where it transfers heat to the housing 50 and condenses.

[0083] The refrigerant CO condensed in the internal region 10b of the upper member 11 is transported by capillary action in the grooves 10d of the internal region 10b to the capillary flow path 4. In the capillary flow path 4, the condensed refrigerant CO returns by capillary action to the heat receiving part 3. As described above, the above-mentioned circulation cycle of the refrigerant CO is formed in the internal space 20, thereby realizing cooling of the heat source 2.

[0084] 11A, first, the vapor chamber 1 is designed in a computer HW having a CPU 60, a memory 61, an external storage device 62, an operation unit 63, a display unit 64, and an internal bus 65, by the CPU 60 executing a software program read from the external storage device 62 into the memory 61 in accordance with an operation via the operation unit 63. The execution result is displayed on the display unit 64, for example. The information processing device 100, whose function is realized by the computer executing this program, determines the maximum distance L between adjacent reinforcing members. ｓｐ．ｍａｘ The process of calculating [mm] and the process of determining whether the first to fourth conditions are satisfied, that is, the design process (design method) of the vapor chamber 1 shown in FIG. 11B, is performed.

[0085] 11B, first, the information processing device 100 performs initial settings (step S1). In the initial settings, the size, shape, and heat generation amount of the heat source 2 are set, the type and amount of refrigerant CO are set, and the overall size of the vapor chamber 1, the position and size of the heat receiving portion 3, and the shape and size of the portion of the vapor chamber 1 other than the capillary flow path 4 are set. Pure water, an organic solvent, or a mixture thereof is selected as the refrigerant CO, and copper or the like is used as the material of the vapor chamber 1 as a member capable of forming an airtight structure. As a result, the heat input per unit time Q ｉｎ [W], latent heat of vaporization Q per unit mass of fluid mass ＬＨ [J / kg], density of refrigerant CO [kg / m ３ ], the surface tension σ [N / m] of the fluid mass CA relative to the inner wall surface, and the contact angle θ [rad] between the refrigerant CO and the inner wall surface are determined. In addition, the length h [m] and volume V [m ３ ] is determined by substituting the length from the heat receiving portion 3 to the outer edge of the internal space 20, but any value can be set. In this step S1, the material and size of the housing 50 are determined, and therefore the longitudinal elastic modulus E and the second moment of area I are also determined.

[0086] Next, the information processing device 100 calculates the uniformly distributed load w [N / mm ２ ] is calculated (step S10). Here, the uniformly distributed load w [N / mm ２ ] is the internal temperature T of the vapor chamber 1 in the high-temperature process in which the vapor chamber 1 operates. ｖｋ Saturated vapor pressure P of refrigerant CO at [K] ｓ．ｖｃ It is calculated based on [Pa]. ｓ．ｖｃ [Pa] is calculated by the Antoine equation when the refrigerant CO is a pure substance, and by the Wilson equation when the refrigerant CO is a mixed substance. ２ ], it is calculated based on the external force expected to be applied to the vapor chamber 1. For example, the external force per unit area of ​​the housing 50 is calculated as a uniformly distributed load w [N / mm ２ ] can be used.

[0087] Next, the information processing device 100 calculates the bending deformation tolerance δ of the housing 50. ｃ Based on this, the maximum distance L between adjacent spacers 42 ｓｐ．ｍａｘ [mm] is calculated (step S11). In this embodiment, the diameter of the bottom surface of the cylindrical spacer 42 is assumed to be fixed.

[0088] Next, the information processing device calculates N １．Ｃ , N ２．Ｐ , S Ａ１．ｉ [m ２ ], S Ａ２．ｊ [m ２ ], v １．ｉ [m / s], v ２．ｊ [m / s] is calculated (step S2). Ａ１．ｉ [m ２ ] are the same, and S Ａ２，ｊ [m ２ ] are the same, and v １．ｉ Value of [m / s], v ２．ｊ If the values ​​of [m / s] are the same, these values ​​are easy to calculate. This determines the cross-sectional areas of the first and second micro-channels 31 and 32 and the velocity of the fluid mass CA. Note that in step S2, the maximum distance L ｓｐ．ｍａｘ The calculation is performed assuming that there is no flow path in the portion where the spacer 42 with a setting of [mm] exists and the refrigerant CO does not flow.

[0089] Next, the information processing device sets the size of the capillary channel 4 (step S3). Here, H [m], W [m], L [m] for the first minute channel 31 are set. ＤＴ [m], L ＤＰ The values ​​of design parameters related to the flow path structure, such as [m], ε, P1, and P2, are set. These design parameter values ​​are calculated based on the N １．Ｃ , N ２．Ｐ , S Ａ１．ｉ [m ２ ], S Ａ２，ｊ [m ２ ], v １．ｉ [m / s], v ２．ｊ It is constrained by [m / s].

[0090] Next, the information processing device calculates the capillary force f using the formulas (5), (10), and (14). ｃ [N], f ｃ．ｇａｐ [N], f ｃ．ｇａｐ．ｂｔｍ [N] is calculated (step S4), where the value determined and set up to this point is used.

[0091] Next, the information processing device calculates the resistance F Ｒ [N] is calculated (step S5). First, the viscous force f is calculated using equation (6). Ｒ１ [N] is calculated. ｗ．ｓｐ [Pa], τ ｗ．ｄｐ [Pa] is the value of v obtained in step S2 when the refrigerant CO is a Newtonian fluid. １．ｉ Value of [m / s], v ２．ｊ It can be calculated by multiplying the velocity gradient on the wall surface based on the value of [m / s] by the viscosity coefficient of the refrigerant CO. Ｒ２ [N], inertia force f Ｒ３ [N], electromagnetic force f Ｒ４ [N] is additionally calculated depending on the situation in which the vapor chamber 1 is used.

[0092] Next, the information processing device calculates the accelerations a, a using equations (3), (11) to (13), and (15) to (17). ｇａｐ , a ｇａｐ．ｂｔｍ (step S6), and the total work is calculated using equation (18) (step S7).

[0093] Next, the information processing device determines whether the calculation results thus far satisfy all of the first, second, and fourth conditions, or whether the first, third, and fourth conditions are satisfied (step S8). If they are not satisfied (step S8; No), the information processing device returns to step S1, and the processes of steps S1 to S8 are repeated until step S8 becomes Yes. During this repetition, the values ​​of the design parameters related to the flow path structure are changed until the first to fourth conditions are satisfied.

[0094] If the calculation results satisfy all of the first, second, and fourth conditions, or the first, third, and fourth conditions (step S8; Yes), the information processing device terminates the design process, assuming that the values ​​of the design parameters related to the flow path structure of the capillary flow path 4 have been obtained.

[0095] After this design process, the vapor chamber 1 is manufactured based on this design method. In the manufacturing process of the vapor chamber 1, the allowable bending deformation amount of the housing 50 is set to δ ｃ [mm], and the longitudinal elastic modulus of the housing 50 is E [N / mm ２ ], and the second moment of area of ​​the housing 50 is I [mm ２ ], and the uniformly distributed load, which is the load per unit length applied to the housing 50 due to the internal pressure or external pressure generated in the internal space 20, is w [N / mm], the interval L between the adjacent reinforcing members (the spacer 42 and the joining protrusion 17) is ｓｐ The vapor chamber 1 is manufactured by forming reinforcing members (spacers 42 and joining protrusions 17) in the internal space 20 of the housing 50 so that the distance [mm] satisfies the above formula (6). In this manufacturing process, the housing 50 having the flow path structure of the capillary flow path 4 based on the determined design parameter values ​​is formed from a selected material, and the selected refrigerant CO is sealed in the internal space 20 of the housing 50, thereby manufacturing the vapor chamber 1.

[0096] The vapor chamber 1 manufactured based on this design method has a bending deformation limit of the housing 50 due to high heat of δ ｃ The refrigerant CO, the material of the vapor chamber 1, and the flow path structure of the capillary flow path 4 are within the range of 0.05 to 0.15, and either all of the first, second, and fourth conditions are satisfied, or all of the first, third, and fourth conditions are satisfied. As long as the first to fourth conditions are satisfied, the flow path structure is not limited to those shown in Figures 6A to 9. For example, in Figures 7A and 7B, the connecting portion 31B has first connecting portions 31B-1 and second connecting portions 31B-2 arranged alternately, but this ratio can be changed by changing the value of ε.

[0097] 12, the vapor chamber 1 can be used as a mounting substrate for mounting LED (Light Emitting Diode) elements 70. A thin circuit board 71 is formed on the upper surface of the vapor chamber 1 as an insulating layer, and the LED elements 70 are densely mounted thereon, with the region where the LED elements 70 are mounted forming the heat receiving section 3. Electrodes 72 that can be electrically connected to the outside are also provided in the region of the thin circuit board 71 other than the heat receiving section 3.

[0098] In practice, a ground layer (not shown) for grounding the LED element 70 is formed on the thin circuit board 71. Furthermore, as shown in FIG. 13A , a bottom resist pattern 73, which is an insulating layer, a wiring pattern 74, which is a conductive layer, and a top resist pattern 75, which is an insulating layer, are formed in this order on the ground layer, and the LED element 70 is mounted thereon. As shown in FIG. 13B , the signal electrode 70 a of the LED element 70 is soldered to the wiring pattern 74 by a reflow process through openings in the top resist pattern 75. The ground electrode 70 b of the LED element 70 is soldered to the ground layer by a reflow process through openings in the bottom resist pattern 73 and the top resist pattern 75. The vapor chamber 1 is designed to withstand the maximum temperature in the temperature profile of the reflow process.

[0099] A comparison was made between the LED junction temperature in the vapor chamber 1 according to this embodiment and that in a copper substrate. The junction temperature refers to the surface temperature of the LED element 70, and is the operating compensation temperature of the LED element 70. As shown in FIG. 14, it was found that the junction temperature was suppressed by approximately 10 K compared to the copper substrate. Furthermore, it was found that in the vapor chamber 1 according to this embodiment, the temperature of the mounted LED element 70 was almost uniform regardless of location, and the temperature distribution was smoothed.

[0100] [Evaluation Results] An evaluation was actually performed using a vapor chamber 1 manufactured using this design method. The heat source 2 was a ceramic heater, and cooling was performed using an aluminum heat sink 6 attached to the vapor chamber 1. As shown in Figures 15A, 15B, and 15C, the installation angle of this vapor chamber 1 was set to 0 degrees, 90 degrees, and 180 degrees, and the thermal resistance was confirmed for each angle. To confirm the soundness of the evaluation system, a copper plate (C1020) of the same shape as the vapor chamber 1 was used as a comparison, and the thermal resistance of each was calculated using the following formula, and the results were compared. The evaluation results are shown in Figure 16. Here, R ｔｈ．ａｌｌ [K.W. －１ ] is the total thermal resistance of the vapor chamber 1 and the copper plate. ｈ [K] is the backside temperature of the ceramic heater, T ａ [K] indicates room temperature, and Q ｈ [W] indicates the power input to the ceramic heater.

[0101] 16, the difference in thermal resistance of the copper plate due to the installation position is about 0.5%, which is a value attributable to the characteristics of the evaluation system and serves as a reference value for evaluating the thermal resistance of the vapor chamber 1. As a result of the evaluation experiment, the difference in thermal resistance of the vapor chamber 1 due to the installation position was about 0.5%, which is equivalent to that of the copper plate. Since no difference beyond the difference in data attributable to the evaluation system was observed, it was confirmed that the thermal resistance of the vapor chamber 1 designed using the design method according to this embodiment is constant regardless of the influence of the installation position.

[0102] In addition, the input power Q to the ceramic heater ｈ Even if [W] increases, the total thermal resistance of the copper plate R ｔｈ．ａｌｌ [K.W. －１ ] is almost the same, but the input power Q ｈ The higher [W], the greater the total thermal resistance R of the vapor chamber 1. ｔｈ．ａｌｌ [K.W. －１ This indicates that the vapor chamber 1 has a better heat diffusion effect than the copper plate.

[0103] In this way, the resistance force F acting on the fluid mass CA of the refrigerant COＲ By determining the design parameters that define the microchannel structure so as to satisfy the formula (3) in consideration of the above, various resistance forces F against the refrigerant CO can be obtained. Ｒ The refrigerant CO can move against the force [N], thereby realizing the circulation of the refrigerant CO. Furthermore, by appropriately defining the values ​​of parameters resulting from the geometric shape, such as the volume V of the fluid mass CA, depending on the shape of the flow path, it is possible to obtain a conditional expression that the shape of the capillary flow path 4 must satisfy for a capillary flow path 4 having an arbitrary shape.

[0104] As described above in detail, according to the embodiment, the spacing between adjacent spacers 42 is set to L so that the housing 50 does not deform. ｓｐ [mm], the bending deformation of the housing 50 due to high temperature is within the tolerance δ ｃ Since the size can be kept within this range, deformation due to an increase in internal pressure caused by high heat or deformation due to external forces can be suppressed.

[0105] While the spacers 42 and the joining protrusions 17 function to provide mechanical strength, it is difficult to provide a micro-channel for returning the refrigerant CO by capillary force in the area where the spacers 42 are provided. Therefore, if an excessive number of spacers 42 are provided, it may not be possible to achieve the required circulation flow rate of the refrigerant CO in the vapor chamber 1. Therefore, according to the vapor chamber 1 of this embodiment, the capillary force f applied to the fluid mass CA of the refrigerant CO in the first micro-channel 31 of the capillary channel 4 that generates a two-dimensional lattice-like capillary force formed at a uniform lattice pitch P1 is ｃ [N] is the resistance force F that prevents the movement of the fluid mass CA Ｒ The materials of the refrigerant CO and the vapor chamber 1 can be selected and the values ​​of the design parameters indicating the flow path structure of the capillary flow path 4 can be determined so that the force [N] exceeds the maximum force [N] and the work done by the force moving the fluid mass CA becomes positive overall, and dryout does not occur in the heat receiving part 3. This allows continuous thermal diffusion to be performed without the thermal performance being affected by resistance. This achieves the desired thermal performance and suppresses deformation due to an increase in internal pressure caused by high heat or deformation due to external forces.

[0106] The joining protrusions 17 may be omitted. In this case, the spacers 42 are arranged in a two-dimensional lattice pattern, for example, and the maximum spacing L ｓｐ．ｍａｘ (the above formula (6)) must be maintained.

[0107] In the above embodiment, the vapor chamber 1 is described as being used as a mounting substrate for mounting the LED element 70. However, this is not limiting and the vapor chamber 1 can be used as a mounting substrate for mounting other electronic components.

[0108] In the above embodiment, the cross section of the flow path perpendicular to the flow direction of the fluid mass WA is rectangular, but this is not limiting. For example, the present invention can be applied to a flow path having a cross section of another polygonal shape.

[0109] This invention allows various embodiments and modifications without departing from the broad spirit and scope of this invention. Furthermore, the above-described embodiments are intended to explain this invention and do not limit the scope of this invention. That is, the scope of this invention is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of the invention equivalent thereto are considered to be within the scope of this invention.

[0110] In addition, this application claims priority based on Japanese Patent Application No. 2023-70713 filed on April 24, 2023, and the specification, claims, and drawings of Japanese Patent Application No. 2023-70713 are incorporated herein by reference.

[0111] The present invention can be applied to a vapor chamber that cools or heats a heat source, and is suitable when the vapor chamber is used as a mounting substrate for electronic components.

[0112] 1 Vapor chamber, 2 Heat source (body to be cooled), 3 Heat receiving portion, 4 Capillary flow path, 5 Vapor flow path, 6 Heat sink, 10 Lower member, 10a Outer edge portion, 10b Internal region, 10c Dimple, 10d Groove portion, 11 Upper member, 12 Intermediate member, 12a Outer edge portion, 12b Internal region, 12c Through hole, 15 Capillary flow path forming region, 16 Vapor flow path forming region, 17 Joining protrusion, 20 Internal space (sealed space), 31 First micro flow path, 31A Straight tube portion, 31B Connecting portion, 31B-1 First connecting portion, 31B-2 Second connecting portion, 32 Second micro flow path, 40, 41 Joining protrusion, 42 Spacer, 50 Housing, 60 CPU, 61 Memory, 62 External storage device, 63 Operation unit, 64 Display unit, 65 Internal bus, 70 LED element, 70a signal electrode, 70b ground electrode, 71 thin circuit board, 72 electrode, 73 lower surface resist pattern, 74 wiring pattern, 75 upper surface resist pattern, 100 information processing device, CO refrigerant, CA fluid mass

Claims

1. A vapor chamber design method executed by an information processing device, comprising: The vapor chamber is A flat housing having an internal space formed therein, a heat receiving portion that receives heat from an object to be cooled; a vapor flow path through which the refrigerant vaporized in the heat receiving portion moves; a capillary flow path that sends the refrigerant liquefied by heat radiation to the heat receiving portion by capillary force, a plurality of reinforcing members for reinforcing the housing in a thickness direction are arranged in the internal space along a surface direction of the housing; The allowable bending deformation of the housing is δ ｃ [mm], and the longitudinal elastic modulus of the housing is E [N / mm ２ ] and the second moment of area of ​​the housing is I [mm ２ ], and the uniformly distributed load, which is the load per unit length applied to the housing due to the internal pressure or external pressure generated in the internal space, is w [N / mm], the interval L of the adjacent reinforcing members is ｓｐ [mm] is defined to satisfy the following formula: [Equation 1] How to design a vapor chamber.

2. The capillary channel is a first microchannel which is a two-dimensional lattice-shaped channel formed at a uniform lattice pitch along the surface direction of the vapor chamber; The first microchannel is a straight pipe portion for sending the refrigerant fluid mass in one direction; connecting portions that connect the straight pipe portions to each other at lattice points of the first microchannel, a first condition being that the acceleration generated in the fluid mass due to the capillary force applied to the fluid mass in the straight pipe section is positive; a second condition being that the acceleration generated in the fluid mass due to the capillary force applied to the fluid mass at the connecting portion is positive; a third condition is that the sum of the work done by the force applied to the fluid mass in the straight pipe section and the work done by the force applied to the fluid mass in the connecting section is positive; a fourth condition that the total amount of latent heat of evaporation per unit time of the fluid mass returning from the capillary flow path to the heat receiving portion exceeds the amount of heat input per unit time from the cooled body to the heat receiving portion; selecting materials for the refrigerant and the vapor chamber and determining values ​​of design parameters related to a flow path structure of the capillary flow path so that all of the first condition, the second condition, and the fourth condition are satisfied, or so that all of the first condition, the third condition, and the fourth condition are satisfied; The vapor chamber design method according to claim 1 .

3. A vapor chamber design method executed by an information processing device, comprising: The vapor chamber is A flat housing having an internal space formed therein, a heat receiving portion that receives heat from an object to be cooled; a vapor flow path through which the refrigerant vaporized in the heat receiving portion moves; a capillary flow path that sends the refrigerant liquefied by heat radiation to the heat receiving portion by capillary force, The capillary channel is a first microchannel which is a two-dimensional lattice-shaped channel formed at a uniform lattice pitch along the surface direction of the vapor chamber; The first microchannel is a straight pipe portion for sending the refrigerant fluid mass in one direction; connecting portions that connect the straight pipe portions to each other at lattice points of the first microchannel, a first condition being that the acceleration generated in the fluid mass due to the capillary force applied to the fluid mass in the straight pipe section is positive; a second condition being that the acceleration generated in the fluid mass due to the capillary force applied to the fluid mass at the connecting portion is positive; a third condition is that the sum of the work done by the force applied to the fluid mass in the straight pipe section and the work done by the force applied to the fluid mass in the connecting section is positive; a fourth condition that the total amount of latent heat of evaporation per unit time of the fluid mass returning from the capillary flow path to the heat receiving portion exceeds the amount of heat input per unit time from the cooled body to the heat receiving portion; selecting materials for the refrigerant and the casing and determining values ​​of design parameters related to a flow path structure of the capillary flow path so that all of the first condition, the second condition, and the fourth condition are satisfied, or so that all of the first condition, the third condition, and the fourth condition are satisfied; How to design a vapor chamber.

4. The acceleration generated in the fluid mass due to the capillary force in the straight pipe section is defined as a [m / s ２ ]year, The density of the fluid mass is ρ [kg / m ３ ]year, The volume of the fluid mass is V [m ３ ]year, The capillary force in the straight tube section is f ｃ [N], The resistance force that prevents the movement of the fluid mass due to the capillary force is F Ｒ When [N] is used, [Equation 2] is a conditional expression representing the first condition, The capillary channel is second microchannels extending in a thickness direction of the housing and two-dimensionally arranged at a uniform arrangement pitch in a surface direction of the housing; The connecting portion is a first connecting portion that is not connected to the second microchannel; a second connection portion connected to the second microchannel, The acceleration generated in the fluid mass due to the capillary force at the first connecting portion is a ｇａｐ [m / s ２ ]year, The acceleration generated in the fluid mass due to the capillary force at the second connecting portion is a ｇａｐ．ｂｔｍ [m / s ２ ]year, The capillary force generated in the first connecting portion is f ｃ．ｇａｐ [N], The capillary force generated in the second connecting portion is f ｃ．ｇａｐ．ｂｔｍ When [N] is used, [Equation 3] is a conditional expression representing the second condition, The length of the straight pipe section in the direction in which the fluid mass flows is L ＤＴ [m], The length of the connecting portion in the direction in which the fluid mass flows is set to 2W [m], When the ratio of the number of the first connecting portions to the number of the connecting portions where the fluid mass exists is ε, [Equation 4] is a conditional expression representing the third condition, The amount of heat input per unit time from the object to be cooled to the heat receiving part is Q ｉｎ [W], The latent heat of vaporization per unit mass of the fluid mass is Q ＬＨ [J / kg], The number of the first microchannels in contact with the outer edge of the heat receiving portion is N １．Ｃ year, The number of the second minute flow paths in contact with the heat receiving portion is N ２．Ｐ year, i (i=1 to N) in contact with the outer edge of the heat receiving part １．Ｃ The cross-sectional area of ​​the cross section of the first microchannel (a natural number of which is a positive integer) perpendicular to the direction in which the fluid mass flows is defined as S Ａ１．ｉ [m ２ ]year, j (j=1 to N) in contact with the heat receiving portion ２．Ｐ The cross-sectional area of ​​the cross section of the second microchannel (a natural number of which is a positive integer) perpendicular to the direction in which the fluid mass flows is defined as S Ａ２．ｊ [m ２ ]year, The velocity of the fluid mass flowing in the i-th first minute channel in contact with the outer edge of the heat receiving part is defined as v １．ｉ [m / s], The velocity of the fluid mass flowing in the j-th second minute flow path in contact with the heat receiving portion is defined as v ２．ｊ When expressed as [m / s], [Equation 5] is a conditional expression representing the fourth condition, The vapor chamber design method according to claim 3 .

5. the straight pipe portion has a rectangular cross section perpendicular to the direction in which the fluid mass flows, The distance between the inner wall surfaces facing each other in the thickness direction in the straight pipe portion is 2H [m], The distance between the inner wall surfaces facing each other in the surface direction in the straight pipe portion is 2W [m], The surface tension of the fluid mass relative to the inner wall surface is defined as σ [N / m], When the contact angle between the fluid mass and the inner wall surface is θ [rad], The capillary force f generated in the fluid mass in the straight pipe section ｃ [N] is [Equation 6] It is defined in The capillary force f generated in the fluid mass at the first connecting portion ｃ．ｇａｐ [N] is [Equation 7] It is defined in The capillary force f generated in the fluid mass at the second connecting portion ｃ．ｇａｐ．ｂｔｍ [N] is [Equation 8] As defined in The vapor chamber design method according to claim 4.

6. The length of the fluid mass in the direction in which the fluid mass flows is defined as h [m], The arrangement pitch of the straight pipe sections in the direction in which the fluid mass flows is L ＤＰ [m], The shear stress occurring on the inner wall surface along the thickness direction of the first microchannel is defined as τ ｗ．ｓｐ [Pa], The shear stress occurring on the inner wall surface along the surface direction of the first microchannel is defined as τ ｗ．ｄｐ When [Pa] is used, The resistance force F Ｒ The viscous force f generated in the fluid mass flowing through the first microchannel is included in Ｒ１ [N] is [Equation 9] As defined in The vapor chamber design method according to claim 5.

7. The resistance force that prevents the movement of the fluid mass due to the capillary force includes at least one of gravity, inertial force, and electromagnetic force. The vapor chamber design method according to claim 3 .

8. A method for manufacturing a vapor chamber, comprising: The vapor chamber is A flat housing having an internal space formed therein, a heat receiving portion that receives heat from an object to be cooled; a vapor flow path through which the refrigerant vaporized in the heat receiving portion moves; a capillary flow path that sends the refrigerant liquefied by heat radiation to the heat receiving portion by capillary force, a plurality of reinforcing members for reinforcing the housing in a thickness direction are arranged in the internal space along a surface direction of the housing; The allowable bending deformation of the housing is δ ｃ [mm], and the longitudinal elastic modulus of the housing is E [N / mm ２ ] and the second moment of area of ​​the housing is I [mm ２ ], and the uniformly distributed load, which is the load per unit length applied to the housing due to the internal pressure or external pressure generated in the internal space, is w [N / mm], the interval L of the adjacent reinforcing members is ｓｐ The reinforcing member is formed in the internal space of the housing so that [mm] satisfies the following formula: [Equation 10] Method for manufacturing a vapor chamber.

9. The capillary channel is a first microchannel which is a two-dimensional lattice-shaped channel formed at a uniform lattice pitch along the surface direction of the vapor chamber; The first microchannel is a straight pipe portion for sending the refrigerant fluid mass in one direction; connecting portions that connect the straight pipe portions to each other at lattice points of the first microchannel, a first condition being that the acceleration generated in the fluid mass due to the capillary force applied to the fluid mass in the straight pipe section is positive; a second condition being that the acceleration generated in the fluid mass due to the capillary force applied to the fluid mass at the connecting portion is positive; a third condition is that the sum of the work done by the force applied to the fluid mass in the straight pipe section and the work done by the force applied to the fluid mass in the connecting section is positive; a fourth condition that the total amount of latent heat of evaporation per unit time of the fluid mass returning from the capillary flow path to the heat receiving portion exceeds the amount of heat input per unit time from the cooled body to the heat receiving portion; selecting materials for the refrigerant and the housing and determining values ​​of design parameters related to a flow path structure of the capillary flow path so that all of the first condition, the second condition, and the fourth condition are satisfied, or so that all of the first condition, the third condition, and the fourth condition are satisfied; forming the housing having a flow path structure of the capillary flow path based on the determined design parameter values ​​from the selected material; The selected refrigerant is sealed in the internal space of the housing. The method for manufacturing a vapor chamber according to claim 8.

10. A method for manufacturing a vapor chamber, comprising: The vapor chamber is A flat housing having an internal space formed therein, a heat receiving portion that receives heat from an object to be cooled; a vapor flow path through which the refrigerant vaporized in the heat receiving portion moves; a capillary flow path that sends the refrigerant liquefied by heat radiation to the heat receiving portion by capillary force, The capillary channel is a first microchannel which is a two-dimensional lattice-shaped channel formed at a uniform lattice pitch along the surface direction of the vapor chamber; The first microchannel is a straight pipe portion for sending the refrigerant fluid mass in one direction; connecting portions that connect the straight pipe portions to each other at lattice points of the first microchannel, a first condition being that the acceleration generated in the fluid mass due to the capillary force applied to the fluid mass in the straight pipe section is positive; a second condition being that the acceleration generated in the fluid mass due to the capillary force applied to the fluid mass at the connecting portion is positive; a third condition is that the sum of the work done by the force applied to the fluid mass in the straight pipe section and the work done by the force applied to the fluid mass in the connecting section is positive; a fourth condition that the total amount of latent heat of evaporation per unit time of the fluid mass returning from the capillary flow path to the heat receiving portion exceeds the amount of heat input per unit time from the cooled body to the heat receiving portion; selecting materials for the refrigerant and the housing and determining values ​​of design parameters related to a flow path structure of the capillary flow path so that all of the first condition, the second condition, and the fourth condition are satisfied, or so that all of the first condition, the third condition, and the fourth condition are satisfied; forming the housing having a flow path structure of the capillary flow path based on the determined design parameter values ​​from the selected material; The selected refrigerant is sealed in the internal space of the housing. Method for manufacturing a vapor chamber.

11. A flat housing having an internal space formed therein, a heat receiving portion that receives heat from an object to be cooled; a vapor flow path through which the refrigerant vaporized in the heat receiving portion moves; a capillary flow path that sends the refrigerant liquefied by heat radiation to the heat receiving portion by capillary force, an internal space of the housing is divided into a first region in which the vapor flow path is formed and a second region in which the capillary flow path is formed in a surface direction of the housing; a plurality of reinforcing members for reinforcing the housing in a thickness direction are arranged in the first region and the second region along a surface direction of the housing; Vapor chamber.

12. The allowable bending deformation of the housing is δ ｃ [mm], and the longitudinal elastic modulus of the housing is E [N / mm ２ ] and the second moment of area of ​​the housing is I [mm ２ ], and the uniformly distributed load, which is the load per unit length applied to the housing due to the internal pressure or external pressure generated in the internal space, is w [N / mm], the interval L of the adjacent reinforcing members is ｓｐ [mm] is defined to satisfy the following formula: [0011] The vapor chamber of claim 11.

13. The capillary channel is a first microchannel which is a two-dimensional lattice-shaped channel formed at a uniform lattice pitch along the surface direction of the vapor chamber; The first microchannel is a straight pipe portion for sending the refrigerant fluid mass in one direction; connecting portions that connect the straight pipe portions to each other at lattice points of the first microchannel, a first condition being that the acceleration generated in the fluid mass due to the capillary force applied to the fluid mass in the straight pipe section is positive; a second condition being that the acceleration generated in the fluid mass due to the capillary force applied to the fluid mass at the connecting portion is positive; a third condition is that the sum of the work done by the force applied to the fluid mass in the straight pipe section and the work done by the force applied to the fluid mass in the connecting section is positive; a fourth condition that the total amount of latent heat of evaporation per unit time of the fluid mass returning from the capillary flow path to the heat receiving portion exceeds the amount of heat input per unit time from the cooled body to the heat receiving portion; The refrigerant, the material of the vapor chamber, and the flow path structure of the capillary flow path satisfy all of the first condition, the second condition, and the fourth condition, or all of the first condition, the third condition, and the fourth condition. The vapor chamber of claim 11.

14. A flat housing having an internal space formed therein, a heat receiving portion that receives heat from an object to be cooled; a vapor flow path through which the refrigerant vaporized in the heat receiving portion moves; a capillary flow path that sends the refrigerant liquefied by heat radiation to the heat receiving part by capillary force; and a flat vapor chamber formed in the housing, The capillary channel is a first microchannel which is a two-dimensional lattice-shaped channel formed at a uniform lattice pitch along the surface direction of the vapor chamber; second microchannels extending in a thickness direction of the housing and two-dimensionally arranged at a uniform arrangement pitch in a surface direction of the housing; The first microchannel is a straight pipe portion for sending the refrigerant fluid mass in one direction; connecting portions that connect the straight pipe portions to each other at lattice points of the first microchannel, The connecting portion is a first connecting portion that is not connected to the second microchannel; a second connection portion connected to the second microchannel, a first condition being that the acceleration generated in the fluid mass due to the capillary force applied to the fluid mass in the straight pipe section is positive; a second condition being that the acceleration generated in the fluid mass due to the capillary force applied to the fluid mass at the connecting portion is positive; a third condition is that the sum of the work done by the force applied to the fluid mass in the straight pipe section and the work done by the force applied to the fluid mass in the connecting section is positive; a fourth condition that the total amount of latent heat of evaporation per unit time of the fluid mass returning from the capillary flow path to the heat receiving portion exceeds the amount of heat input per unit time from the cooled body to the heat receiving portion; The refrigerant, the material of the housing, and the flow path structure of the capillary flow path satisfy all of the first condition, the second condition, and the fourth condition, or all of the first condition, the third condition, and the fourth condition. Vapor chamber.

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