Heat transfer material

Abstract

To provide a new heat transfer material that efficiently diffuses heat in the surface direction.SOLUTION: A heat transfer material 10 (10a to 10e) includes multiple rod-shaped fibers 24 (24c, 24d, 24e), each of which extends along a reference plane parallel to heat transfer material 21 (21a to 21e) of the heat transfer material 10 (10a to 10e). The fibers 24 (24c, 24d, 24e) are arranged on the reference plane such that the thermal conductivity between a center of gravity 32 (32a to 32e) of the heat transfer material 10 (10a to 10e) on the reference plane and multiple equally spaced imaginary points 34 (34a to 34e) on a circle 30 (30a, 30b) centered on center of gravity 32 (32a to 32e) on the reference plane satisfies a predetermined formula for all imaginary points 34 (34a to 34e).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a heat transfer member. [Background technology]

[0002] Conventionally, there is known a technique for transferring heat from an integrated circuit or the like by using fibers such as carbon fibers as a thermally conductive material. For example, Patent Document 1 discloses a unidirectional fiber-reinforced carbon composite as a thermally conductive material, in which the cross section perpendicular to the fiber arrangement direction is made sufficiently large and can be processed to a desired size. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 08-225375 Summary of the Invention [Problem to be solved by the invention]

[0004] The fiber-reinforced carbon composite material in Patent Document 1 is characterized in that the fiber orientation direction is parallel to the longitudinal direction, and at least one side surface of a polygonal prism is joined to the side surface of another polygonal prism via a joining layer, etc. Therefore, although heat can be transferred in the longitudinal direction of the polygonal prism, it is difficult to transfer heat efficiently in the lateral direction.

[0005] The present disclosure has been made in consideration of these points, and has an object to provide a new heat transfer member that efficiently diffuses heat in the planar direction. [Means for solving the problem]

[0006] The heat transfer member of the present disclosure comprises: A plurality of fibers; a top surface on which a heat transfer target member is placed, Each of the plurality of fibers extends along a reference plane that is a plane parallel to the upper surface, The fibers are arranged on the reference plane so that the thermal conductivity between the center of gravity of the heat transfer member on the upper surface and a plurality of equally spaced virtual points on a circle centered on the center of gravity on the upper surface satisfies the following formula for all the virtual points: 0.8≦W 1~n / W ave. ≦1.2 n: the number of each of the plurality of virtual points W 1~n : Thermal conductivity between the center of gravity and the virtual point W ave. : Average value of thermal conductivity between the center of gravity and the virtual point

[0007] In the heat transfer member of the present disclosure, The circle having the center of gravity on the upper surface as its center may be the circle having the largest diameter among circles tangent to the outer edge of the heat transfer member.

[0008] In the heat transfer member of the present disclosure, The circle centered on the center of gravity on the upper surface may have a diameter that is a predetermined multiple of the diameter of the largest circle tangent to the outer edge of the heat transfer member, which is greater than or equal to 0.5 and less than 1.0.

[0009] In the heat transfer member of the present disclosure, The fiber bundle may include fibers that extend parallel to one another.

[0010] In the heat transfer member of the present disclosure, On the reference surface, the fibers may be arranged radially along a direction from an arbitrary point on the reference surface toward an outer edge of the heat transfer member.

[0011] The heat transfer member of the present disclosure comprises: a fiber unit in which the fibers extending parallel to each other along an upper surface are stacked, The side surfaces of the plurality of fiber units may be in contact with each other.

[0012] In the heat transfer member of the present disclosure, In each of the adjacent fiber units, The fibers of each fiber unit may extend in different directions.

[0013] The heat transfer member of the present disclosure comprises: The fiber unit has a plurality of fiber units each having a triangular prism shape with a vertex having the smallest angle in the direction in which the fiber extends, a heat transfer member disposed on the reference surface so that vertices of the fiber units overlap each other, Each of the fibers may be arranged to extend in a direction from an arbitrary point on the reference plane toward an outer edge of the heat transfer member.

[0014] In the heat transfer member of the present disclosure, Each of the fibers may be arranged to extend along a spiral on the reference surface.

[0015] In the heat transfer member of the present disclosure, The fibers may be arranged on the reference surface such that both ends of the fibers are in contact with or close to each other to form one path.

[0016] In the heat transfer member of the present disclosure, The space factor of each of the fibers may be within a range of 30% to 95%.

[0017] In the heat transfer member of the present disclosure, The thermal conductivity in a direction perpendicular to the reference plane may be within a range of 5 to 200 W / m·K.

[0018] In the heat transfer member of the present disclosure, The ratio of the thermal conductivity in a direction perpendicular to the reference plane to the average value of the thermal conductivity between the center of gravity and each of the virtual points in a direction parallel to the reference plane may be in the range of 10 to 60.

[0019] In the heat transfer member of the present disclosure, Each of the fibers may be a carbon fiber. [Effects of the Invention]

[0020] According to the heat transfer member of the present disclosure, heat can be efficiently diffused in the planar direction. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a perspective view schematically illustrating a configuration of a heat transfer member according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a top view of the heat transfer member shown in FIG. [Figure 3] 2A to 2C are explanatory views sequentially showing a method for manufacturing a fiber unit that constitutes the heat transfer member shown in FIG. [Figure 4] FIG. 10 is a top view of another aspect of a heat transfer member according to an embodiment of the present disclosure. [Figure 5] FIG. 10 is a top view of a heat transfer member according to still another aspect of the present disclosure. [Figure 6] FIG. 10 is a top view of a heat transfer member according to still another aspect of the present disclosure. [Figure 7] FIG. 10 is a top view of a heat transfer member according to still another aspect of the present disclosure. [Figure 8] FIG. 10 is a top view of a heat transfer member according to still another aspect of the present disclosure. [Figure 9] 1 is a schematic view showing the appearance of the heat transfer members in Examples 1 to 7 and 9 to 12. FIG. [Figure 10] FIG. 10 is a schematic diagram showing the appearance of the heat transfer member in Example 8, and also exemplarily shows the locations (measurement samples) cut out for measuring thermal conductivity in each Example and Comparative Example. [Figure 11] 1 is a schematic view showing the appearance of a heat transfer member in Comparative Example 1. FIG. [Figure 12] FIG. 10 is a diagram showing a cut-out area for measuring the thermal conductivity of the heat transfer member in the Z direction. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Figures 1 to 3 are diagrams showing the configuration of a heat transfer member 10 according to an embodiment of the present disclosure. The heat transfer member 10 according to the present embodiment is attached to a heat-transfer target member such as a heat-generating electric component or electronic component, thereby dissipating heat from the heat-transfer target member.

[0023] FIG. 1 is a perspective view schematically illustrating the configuration of a heat transfer member 10 according to this embodiment. As shown in FIG. 1, the heat transfer member 10 according to this embodiment includes a plurality of fibers 24, a material into which the plurality of fibers 24 are impregnated, and an upper surface 21 on which a heat transfer target (not shown) is placed. Here, the material into which the plurality of fibers 24 are impregnated is, for example, a resin. Here, the plurality of fibers 24 may be impregnated into a material such as resin and then fired. The heat transfer member 10 according to this embodiment is formed by stacking a plurality of plate-shaped fiber units 20. As shown in FIG. 2, each fiber unit 20 is composed of a plurality of fibers 24.

[0024] Each fiber 24 has a diameter of 0.5 μm to 200 μm and a longitudinal length of 5 mm or more. Here, organic or inorganic fibers are used as each fiber 24. Examples of organic fibers include thermoplastic synthetic resins such as olefin resins, polyester resins, polyethylene terephthalate resins, polyvinyl acetate resins, ethylene-vinyl acetate copolymer resins, polyamide resins, acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyvinyl ether resins, polyvinyl ketone resins, polyether resins, polyvinyl alcohol resins, diene resins, and polyurethane resins. Examples of organic fibers include fibers made of thermosetting synthetic resins such as phenol resins, melamine resins, furan resins, urea resins, aniline resins, unsaturated polyester resins, and alkyd resins. Examples of organic fibers include fibers made from plant fibers such as wood pulp, paper mulberry, mitsumata, straw, kenaf, bamboo, linter, bagasse, esparto, and sugarcane, as well as fibers refined from these. Other examples include rayon fibers, which are regenerated cellulose fibers; semi-synthetic fibers such as acetate; fluororesin fibers such as polytetrafluoroethylene (PTFE); and silicone resin fibers. The fibers 24 may also be organic fibers coated with metal materials such as copper, silver, aluminum, nickel, and stainless steel. In addition to the organic fibers described above, inorganic fibers such as ceramic fibers, metal fibers, and carbon fibers may also be used. Examples of inorganic fibers include metal fibers such as copper, silver, aluminum, nickel, and stainless steel; carbon fibers; ceramic fibers; and glass fibers. Carbon fibers are particularly preferred for the fibers 24. By using carbon fibers as the fibers 24, sufficient thermal diffusion and rapid heat distribution can be achieved.

[0025] Furthermore, in this embodiment, each fiber 24 extends along a reference plane (a plane in the XY direction in FIGS. 1 and 2 ) that is a plane parallel to the upper surface 21 of the heat transfer member 10. That is, the fibers 24 extend along the reference plane that is a plane in the XY direction, and surfaces made up of such fibers 24 are stacked in the Z direction to form a fiber unit 20. As shown in FIG. 1 , the side surfaces of multiple fiber units 20 are in contact with each other. Furthermore, in adjacent fiber units 20, the extension directions of the fibers 24 of each fiber unit 20 are different from each other. Furthermore, each fiber unit 20 has a triangular prism shape with a vertex that forms the smallest angle in the extension direction of each fiber 24. In this embodiment, each fiber 24 is arranged radially on the reference plane along a direction from any point on the reference plane toward the outer edge of the heat transfer member 10. In the examples shown in Figures 1 and 2, the arbitrary point on the reference plane is the center of gravity of the heat transfer member 10 on the reference plane, but in other embodiments, the arbitrary point on the reference plane may be a point other than the center of gravity of the heat transfer member 10 on the reference plane.

[0026] As shown in FIG. 3(d), the fiber unit 20 has a triangular prism shape including a base extending perpendicular to a reference plane. The fiber unit 20 is composed of fibers 24, and the fibers 24 are arranged in the fiber unit 20 so that they extend parallel to one another. A method for manufacturing such a fiber unit 20 will be described later. In such a fiber unit 20, the extension direction of the base of the isosceles triangle coincides with the extension direction of each cross section of each fiber 24, and the direction of the perpendicular line from the apex of the isosceles triangle to the base coincides with the longitudinal direction of each fiber 24. By arranging such isosceles triangular fiber units 20 on a plane so that the apexes of these fiber units 20 overlap, a heat transfer member 10 as shown in FIG. 2 is obtained. In such a heat transfer member 10, each fiber 24 generally extends in the direction of the perpendicular line from the center of the heat transfer member 10 to the base of the isosceles triangle of each fiber unit 20. That is, the direction in which each fiber 24 extends is generally from the center of the heat transfer member 10 toward the outer edge.

[0027] In such a heat transfer member 10, the plurality of fibers 24 extend along a reference plane (a plane in the XY direction in FIGS. 1 to 3 ) that is a plane parallel to the upper surface 21 of the heat transfer member 10, and the thermal conductivity between the center of gravity 32 of the heat transfer member 10 on the upper surface 21 and a plurality of (for example, five) imaginary points 34 that are equally spaced on a circle 30 centered on the center of gravity 32 on the upper surface 21 satisfies the following formula for all imaginary points 34. That is, in a heat transfer member 10 made up of fiber units 20 as shown in FIG. 2 , each fiber 24 extends in the direction of a perpendicular line from the center (center of gravity 32) of the heat transfer member 10 to the base of the isosceles triangle of each fiber unit 20, so that the thermal conductivity between the center of gravity 32 and each imaginary point 34 is approximately the same, and W 1~n / W ave. is close to 1. 0.8≦W 1~n / W ave. ≦1.2 n: the number of each of the multiple virtual points 34 (specifically, n=5) W 1~n : Thermal conductivity between the center of gravity 32 and each virtual point 34 W ave. : Average value of thermal conductivity between the center of gravity 32 and each virtual point 34 Note that the "thermal conductivity between the center of gravity 32 and each virtual point 34" refers to the overall thermal conductivity between the center of gravity 32 and each virtual point 34, but it may also be the average value between the center of gravity 32 and each virtual point 34, as in the embodiment.

[0028] In the heat transfer member 10, the thermal conductivity W between the center of gravity 32 and each virtual point 34 is 1~n is preferably 100 W / m·K or more and 1000 W / m·K or less, more preferably 200 W / m·K or more and 1000 W / m·K or less, even more preferably 350 W / m·K or more and 1000 W / m·K or less, and particularly preferably 450 W / m·K or more and 1000 W / m·K or less. 1~n When the thickness is in this range, thermal diffusivity and rapid heat uniformity can be more sufficiently ensured along the reference plane (the plane in the XY direction in FIGS. 1 and 2) that is parallel to the upper surface 21 of the heat transfer member 10.

[0029] Here, the circle 30 centered on the center of gravity 32 of the heat transfer member 10 on the upper surface 21 is the circle with the largest diameter among the circles tangent to the outer edge of the heat transfer member 10. That is, in the heat transfer member 10 as shown in FIG. 2 , when the center of gravity 32 is located at a point where the vertices of the isosceles triangles of the fiber units 20 overlap, the circle 30 will be tangent to the base of the isosceles triangle of each fiber unit 20. Note that the circle is not limited to the circle with the largest diameter among the circles tangent to the outer edge of the heat transfer member 10. In another embodiment, the circle centered on the center of gravity 32 of the heat transfer member 10 on the upper surface 21 may have a diameter that is a predetermined multiplication factor relative to the diameter of the largest circle tangent to the outer edge of the heat transfer member 10. Here, the predetermined multiplication factor is a multiplication factor of 0.5 or more and 1.0 or less.

[0030] In the above description, the thermal conductivity between the center of gravity 32 and five imaginary points 34 equally spaced on the circle 30 centered on the center of gravity 32 of the heat transfer member 10 on the upper surface 21 is specified, but the number of imaginary points 34 is not limited to five. The number of imaginary points 34 can be any number equal to or greater than three.

[0031] With the heat transfer member 10 configured as described above, when the heat transfer member 10 is attached to a heat-transferred member such as a heat-generating electrical or electronic component, no matter which point (so-called heat spot) on the upper surface 21 of the heat transfer member 10 is heated by the heat-transferred member, the heat transferred from the heat-transferred member is transferred to an arbitrary point on the reference plane along the extending direction of the fibers 24, and then radially transferred from this arbitrary point on the reference plane toward the outer edge of the heat transfer member 10 along the extending direction of the fibers 24. Therefore, the heat transfer member 10 has sufficient thermal diffusivity and can uniformly diffuse heat along the reference plane (the plane in the XY direction in Figures 1 and 2), which is a plane parallel to the upper surface 21 of the heat transfer member 10.

[0032] In this heat transfer member 10, the space factor of each fiber 24 is within a range of 30% to 95%, preferably 50% to 93%, more preferably 55% to 90%, and even more preferably 65% ​​to 90%. In this case, a space factor of each fiber 24 of 95% or less prevents damage to the heat transfer member 10 due to a decrease in strength. As a result, the heat transfer member 10 as a whole can achieve sufficient thermal conductivity. Furthermore, a space factor of each fiber 24 of 30% or more maintains the heat diffusibility in the planar direction of the heat transfer member 10, ensuring uniform heat distribution in the heat transfer member 10 in a short period of time. Furthermore, the heat transfer member 10 has a thermal conductivity in a direction perpendicular to a reference plane (i.e., the Z direction) that is parallel to the upper surface 21 of the heat transfer member 10, within a range of 5 W / m·K to 200 W / m·K, preferably 5 W / m·K to 100 W / m·K, and even more preferably 5 W / m·K to 60 W / m·K. In this case, by setting the thermal conductivity in the direction perpendicular to the reference plane to 5 W / m·K or more, each fiber 24 arranged on any reference plane can receive and transfer heat, thereby improving the efficiency of thermal diffusion in the heat transfer member 10. Furthermore, by setting the thermal conductivity in the direction perpendicular to the reference plane to 200 W / m·K or less, excessive heat transfer in this direction can be prevented, preventing a decrease in the efficiency of thermal diffusion in the reference plane direction. As a result, thermal diffusivity and rapid heat uniformity in the reference plane can be more sufficiently ensured. The space factor of each fiber 24 in the heat transfer member 10 can be calculated, for example, by using a scanning electron microscope (SEM) and known image analysis software to obtain the average value (e.g., the average value of five points) of values ​​obtained by the following formula for a cross section of the heat transfer member 10 in a direction perpendicular to a reference plane. Space factor (%)=(area occupied by each fiber 24 in the heat transfer member 10) / cross-sectional area of ​​the heat transfer member 10)×100

[0033] Furthermore, the ratio of the thermal conductivity in the direction perpendicular to the reference plane (i.e., the Z direction) to the average value of the thermal conductivity between the center of gravity 32 and each imaginary point 34 in the direction parallel to the reference plane is in the range of 10 to 100, preferably in the range of 10 to 60. In this case, since the ratio of the thermal conductivity in the direction perpendicular to the reference plane to the average value of the thermal conductivity between the center of gravity 32 and each imaginary point 34 in the direction parallel to the reference plane is 10 or more, each fiber 24 arranged on any reference plane can receive and transmit heat, thereby improving the efficiency of thermal diffusion in the heat-transfer member 10. Furthermore, since the ratio of the thermal conductivity in the direction perpendicular to the reference plane to the average value of the thermal conductivity between the center of gravity 32 and each imaginary point 34 in the direction parallel to the reference plane is 100 or less, it is possible to prevent excessive heat transfer in the direction perpendicular to the reference plane, which would otherwise reduce the efficiency of thermal diffusion in the reference plane. As a result, thermal diffusivity and rapid heat uniformity in the direction parallel to the reference plane can be more sufficiently ensured.

[0034] Next, a method for manufacturing the fiber unit 20 will be described with reference to FIG. 3. First, as shown in FIG. 3(a), a plurality of fibers 24 are stacked in contact with each other so that the fibers 24 extend parallel to each other (i.e., so that the fibers 24 extend in the Y direction). In one embodiment, the plurality of fibers 24 may be arranged in series in the Y direction. Next, the fibers 24 are stacked in the Z direction as well. Next, as shown in FIG. 3(b), the fibers 24 are placed in a rectangular parallelepiped container 28 and impregnated with a resin or the like. This bonds the fibers 24 together with the resin or the like. Then, as shown in FIG. 3(c), the bonded fibers 24 are cut into two along a diagonal of the rectangular parallelepiped container 28. At this time, the container 28 is also shown in FIG. 3(c) to make the cutting method easier to understand. However, in reality, the fibers 24 are removed from the container 28 and then cut along the diagonal of the container 28. Next, as shown in FIG. 3(d), the two cut triangular prism-shaped fibers 24 are joined together so that one side of each triangular prism faces the other. This results in a fiber unit 20 in which all of the fibers 24 extend in the same direction (Y direction). Although a container 28 is also shown in FIG. 3(d) to facilitate understanding of the joining method for the two cut triangular prism-shaped fibers 24, the container 28 does not actually exist. Finally, the above-described heat transfer member 10 is obtained by arranging the triangular prism-shaped fibers 24 (fiber units 20) as shown in FIG. 3(d) so that the vertices of the triangular prisms overlap each other (FIGS. 1 and 2). In this heat transfer member, too, the fibers 24 are radially arranged along a reference plane extending parallel to the top surface of the heat transfer member, from any point on the reference plane toward the outer edge of the heat transfer member. The arbitrary point on the reference plane may be the center of gravity of the heat transfer member on the reference plane, or may be a point other than the center of gravity of the heat transfer member on the reference plane.

[0035] Furthermore, in the above description, the heat transfer member 10 is described as being composed of a plurality of fibers 24. However, as another example, the heat transfer member 10 may be composed of a plurality of fiber bundles, with each fiber bundle being composed of fibers 24 extending parallel to one another. In this case, the fiber bundles are arranged radially along a direction from an arbitrary point on the reference plane toward the outer edge of the heat transfer member 10. Note that the arbitrary point on the reference plane may be the center of gravity of the heat transfer member 10 on the reference plane, or the arbitrary point on the reference plane may be a point other than the center of gravity of the heat transfer member 10 on the reference plane.

[0036] The heat transfer member according to this embodiment is not limited to the configuration shown in FIGS. 1 to 3, as long as each fiber extends along a reference plane that is a plane parallel to the upper surface of the heat transfer member, and each fiber is arranged on the reference plane so that the thermal conductivity between the center of gravity of the heat transfer member on the upper surface and a plurality of equally spaced imaginary points on a circle centered on the center of gravity on the upper surface satisfies the following formula for all imaginary points: 0.8≦W 1~n / W ave. ≦1.2 n: Number of each of multiple virtual points W 1~n : Thermal conductivity between the center of gravity and the virtual point W ave. : Average value of thermal conductivity between the center of gravity and the virtual point Hereinafter, the configuration of the heat transfer member according to another aspect of the present embodiment will be described with reference to FIGS.

[0037] FIG. 4 is a top view of a heat transfer member 10a according to another embodiment of the present invention. The heat transfer member 10a shown in FIG. 4 is substantially disk-shaped. On a reference plane parallel to the upper surface 21a of the heat transfer member 10a, fibers (not shown in FIG. 4) extend radially from the center of gravity 32a of the heat transfer member 10a toward the outer edge, similar to the heat transfer member 10 shown in FIG. 2, but a notch 23a is formed in part of the outer edge. In this heat transfer member 10a, a circle 30a centered on the center of gravity 32a of the heat transfer member 10a on the reference plane also has the largest diameter among the circles tangent to the outer edge of the heat transfer member 10a. In other words, if a notch 23a is formed in part of the outer edge of the heat transfer member 10a, the circle 30a will be tangent to the notch 23a. Note that the circle is not limited to the largest diameter among the circles tangent to the outer edge of the heat transfer member 10a (i.e., the notch 23a). In another embodiment, the diameter of the circle centered on the center of gravity 32a of the heat transfer member 10a on the reference plane may be a predetermined magnification of the diameter of the largest circle among those tangent to the outer edge of the heat transfer member 10a (i.e., the notch 23a). Here, the predetermined magnification is a magnification of 0.5 or more and 1.0 or less. Even in the heat transfer member 10a shaped as shown in FIG. 4, the fibers extend from the center (center of gravity 32a) of the heat transfer member 10a toward the outer edge, so the thermal conductivity between the center of gravity 32a and each imaginary point 34a is approximately the same, and W 1~n / W ave. is close to 1. 0.8≦W 1~n / W ave. ≦1.2 n: the number of each of the multiple virtual points 34a (specifically, n=5) W 1~n : Thermal conductivity between the center of gravity 32a and each virtual point 34a W ave. : Average value of thermal conductivity between the center of gravity 32a and each virtual point 34a

[0038] In such a heat transfer member 10a, the fibers are also arranged radially along a direction from an arbitrary point on a reference plane extending parallel to the upper surface 21a of the heat transfer member 10a toward the outer edge of the heat transfer member 10a. Note that the arbitrary point on the reference plane may be the center of gravity of the heat transfer member 10a on the reference plane, or may be a point on the reference plane other than the center of gravity of the heat transfer member 10a.

[0039] With the heat transfer member 10a configured as described above, when the heat transfer member 10a is attached to a heat-transfer-receiving member such as a heat-generating electric or electronic component, no matter which point (so-called heat spot) on the upper surface 21a of the heat transfer member 10a is heated by the heat-transfer-receiving member, the heat transferred from the heat-transfer-receiving member is transferred to an arbitrary point on the reference plane along the extending direction of the fibers, and then radially transferred from this arbitrary point on the reference plane toward the outer edge of the heat transfer member 10a along the extending direction of the fibers. This ensures sufficient thermal diffusivity in the heat transfer member 10a, and also enables heat to be uniformly diffused along the reference plane (the plane in the XY direction in FIG. 4), which is a plane parallel to the upper surface 21a of the heat transfer member 10a.

[0040] Although the above description has been given of an embodiment in which the heat transfer member 10a according to the modified example is composed of a plurality of fibers, as another example, the heat transfer member 10a may be composed of a plurality of fiber bundles, each of which is composed of fibers extending parallel to one another. In this case, the fiber bundles are arranged radially along a direction from an arbitrary point on the reference plane toward the outer edge of the heat transfer member 10a. Note that the arbitrary point on the reference plane may be the center of gravity of the heat transfer member 10a on the reference plane, or may be a point other than the center of gravity of the heat transfer member 10a on the reference plane.

[0041] In the heat-transfer member 10a, the space factor of each fiber is within a range of 30% to 95%. The thermal conductivity in a direction perpendicular to a reference plane, which is a plane parallel to the upper surface 21a of the heat-transfer member 10a (i.e., the Z direction) is within a range of 5 to 200 W / m·K. The ratio of the thermal conductivity in the direction perpendicular to the reference plane (i.e., the Z direction) to the average value of the thermal conductivity between the center of gravity 32a and each imaginary point 34a in a direction parallel to the reference plane is within a range of 10 to 100.

[0042] Furthermore, a heat transfer member having a configuration as shown in FIG. 5 may be used as yet another embodiment of the heat transfer member. FIG. 5 is a top view of a heat transfer member 10b according to the present embodiment. In the heat transfer member 10b shown in FIG. 5, fibers (not shown in FIG. 5) extend radially from the center of gravity 32b of the heat transfer member 10b toward the outer edge on a reference plane parallel to the upper surface 21b of the heat transfer member 10b, similar to the heat transfer member 10 shown in FIG. 2, but the shape is not circular. In this heat transfer member 10b, a circle 30b centered on the center of gravity 32b of the heat transfer member 10b on the reference plane has the largest diameter among the circles tangent to the outer edge of the heat transfer member 10b. Note that the circle is not limited to the circle with the largest diameter among the circles tangent to the outer edge of the heat transfer member 10b. In another embodiment, the diameter of the circle centered on the center of gravity 32b of the heat transfer member 10b on the reference plane may be a predetermined magnification factor relative to the diameter of the largest circle among the circles tangent to the outer edge of the heat transfer member 10b. Here, the predetermined magnification factor is a magnification factor of 0.5 or more and 1.0 or less. Even in the heat transfer member 10b shaped as shown in FIG. 5, each fiber extends from the center (center of gravity 32b) of the heat transfer member 10b toward the outer edge, so the thermal conductivity between the center of gravity 32b and each imaginary point 34b is approximately the same, and W 1~n / W ave. is close to 1. 0.8≦W 1~n / W ave. ≦1.2 n: the number of each of the multiple virtual points 34b (specifically, n=5) W 1~n : Thermal conductivity between the center of gravity 32b and each virtual point 34b W ave. : Average value of thermal conductivity between the center of gravity 32b and each virtual point 34b

[0043] In such a heat transfer member 10b, the fibers are also arranged radially in a direction from an arbitrary point on a reference plane extending parallel to the upper surface 21b of the heat transfer member 10b toward the outer edge of the heat transfer member 10b. Note that the arbitrary point on the reference plane may be the center of gravity of the heat transfer member 10b on the reference plane, or may be a point on the reference plane other than the center of gravity of the heat transfer member 10b.

[0044] With the heat transfer member 10b configured as described above, when the heat transfer member 10b is attached to a heat-transferred member such as a heat-generating electric or electronic component, no matter which point (so-called heat spot) on the upper surface 21b of the heat transfer member 10b is heated by the heat-transferred member, the heat transferred from the heat-transferred member is transferred to an arbitrary point on the reference plane along the extending direction of the fibers, and then radially transferred from this arbitrary point on the reference plane toward the outer edge of the heat transfer member 10b along the extending direction of the fibers. This ensures sufficient thermal diffusivity in the heat transfer member 10b, and also enables heat to be diffused uniformly along the reference plane (the plane in the XY direction in FIG. 5), which is a plane parallel to the upper surface 21b of the heat transfer member 10b.

[0045] Although the above description has been given of an embodiment in which the heat transfer member 10b according to the modified example is composed of a plurality of fibers, as another example, the heat transfer member 10b may be composed of a plurality of fiber bundles, each of which is composed of fibers extending parallel to one another. In this case, the fiber bundles are arranged radially along a direction from an arbitrary point on the reference plane toward the outer edge of the heat transfer member 10b. Note that the arbitrary point on the reference plane may be the center of gravity of the heat transfer member 10b on the reference plane, or may be a point other than the center of gravity of the heat transfer member 10b on the reference plane.

[0046] In this heat-transfer member 10b, the space factor of each fiber is within the range of 30% to 95%. Furthermore, the thermal conductivity in a direction perpendicular to a reference plane, which is a plane parallel to the upper surface 21b of the heat-transfer member 10b (i.e., the Z direction) is within the range of 5 W / m·K to 200 W / m·K. Furthermore, the ratio of the thermal conductivity in the direction perpendicular to the reference plane (i.e., the Z direction) to the average value of the thermal conductivity between the center of gravity 32b and each imaginary point 34b in the direction parallel to the reference plane is within the range of 10 to 100.

[0047] Furthermore, a heat transfer member having a configuration as shown in Fig. 6 may be used as a heat transfer member of yet another embodiment. Fig. 6 is a top view of a heat transfer member 10c of yet another embodiment according to the present embodiment. The heat transfer member 10c shown in Fig. 6 is substantially disk-shaped, and on a reference plane that is a plane parallel to the upper surface 21c of the heat transfer member 10c, fibers 24c extend radially from an arbitrary point on the reference plane toward the outer edge. Note that the arbitrary point on the reference plane may be the center of gravity of the heat transfer member 10c on the reference plane, or the arbitrary point on the reference plane may be a point other than the center of gravity of the heat transfer member 10c on the reference plane.

[0048] Even in such a heat transfer member 10c, the circle centered on the center of gravity 32c of the heat transfer member 10c on the reference plane has the largest diameter among the circles tangent to the outer edge of the heat transfer member 10c. In other words, the circle substantially coincides with the circumferential circle of the heat transfer member 10c. Note that the circle is not limited to the largest diameter among the circles tangent to the outer edge of the heat transfer member 10c. In another embodiment, the circle centered on the center of gravity 32c of the heat transfer member 10c on the reference plane may have a diameter that is a predetermined multiplication factor relative to the diameter of the largest diameter circle among the circles tangent to the outer edge of the heat transfer member 10c. Here, the predetermined multiplication factor is a multiplication factor of 0.5 to 1.0. Even in the heat transfer member 10c shaped as shown in FIG. 6, the fibers extend from the center (center of gravity 32c) of the heat transfer member 10c toward the outer edge, so the thermal conductivity between the center of gravity 32c and each imaginary point 34c is substantially the same, and W 1~n / W ave. is close to 1. 0.8≦W1~n / W ave. ≦1.2 n: the number of each of the multiple virtual points 34c (specifically, n=5) W 1~n : Thermal conductivity between the center of gravity 32c and each virtual point 34c W ave. : Average value of thermal conductivity between the center of gravity 32c and each virtual point 34c

[0049] In such a heat transfer member 10c, the fibers 24c are also arranged radially in a direction from an arbitrary point on a reference plane extending parallel to the upper surface 21c of the heat transfer member 10c toward the outer edge of the heat transfer member 10c. Note that the arbitrary point on the reference plane may be the center of gravity of the heat transfer member 10c on the reference plane, or may be a point other than the center of gravity of the heat transfer member 10c on the reference plane.

[0050] With the heat transfer member 10c configured as described above, when the heat transfer member 10c is attached to a heat-transferred member such as a heat-generating electric or electronic component, no matter which point (so-called heat spot) on the upper surface 21c of the heat transfer member 10c is heated by the heat-transferred member, the heat transferred from the heat-transferred member is transferred to an arbitrary point on the reference plane along the extending direction of the fibers, and then radially transferred from this arbitrary point on the reference plane toward the outer edge of the heat transfer member 10c along the extending direction of the fibers. This ensures sufficient thermal diffusivity in the heat transfer member 10c, and also enables heat to be diffused uniformly along the reference plane (the plane in the XY direction in FIG. 6), which is a plane parallel to the upper surface 21c of the heat transfer member 10c.

[0051] In addition, although the above description has been given of an embodiment in which the heat transfer member 10c according to the modified example is composed of a plurality of fibers 24c, as another example, the heat transfer member 10c may be composed of a plurality of fiber bundles, each of which is composed of fibers 24c extending parallel to one another. In this case, the fiber bundles are arranged radially along a direction from an arbitrary point on the reference plane toward the outer edge of the heat transfer member 10c. Note that the arbitrary point on the reference plane may be the center of gravity of the heat transfer member 10c on the reference plane, or may be a point other than the center of gravity of the heat transfer member 10c on the reference plane.

[0052] In this heat-transfer member 10c, the space factor of each fiber is within the range of 30% to 95%. Furthermore, the thermal conductivity in a direction perpendicular to a reference plane, which is a plane parallel to the upper surface 21c of the heat-transfer member 10c (i.e., the Z direction), is within the range of 5 W / m·K to 200 W / m·K. Furthermore, the ratio of the thermal conductivity in the direction perpendicular to the reference plane (i.e., the Z direction) to the average value of the thermal conductivity between the center of gravity 32c and each imaginary point 34c in the direction parallel to the reference plane is within the range of 10 to 100.

[0053] Furthermore, a heat transfer member having a configuration as shown in Fig. 7 may be used as a heat transfer member of yet another embodiment. Fig. 7 is a top view of a heat transfer member 10d of yet another embodiment according to the present embodiment. In the heat transfer member 10d shown in Fig. 7, fibers 24d extend in a spiral shape from an arbitrary point on a reference plane that is a plane parallel to an upper surface 21d of the heat transfer member 10d toward the outer edge so as to surround the arbitrary point, and the heat transfer member 10d has a substantially disk shape. Note that the arbitrary point on the reference plane may be the center of gravity of the heat transfer member 10d on the reference plane, or the arbitrary point on the reference plane may be a point other than the center of gravity of the heat transfer member 10d on the reference plane.

[0054] Even in such a heat transfer member 10d, a circle centered at an arbitrary point on the reference plane will have the largest diameter among the circles tangent to the outer edge of the heat transfer member 10d. That is, the circle substantially coincides with the circumferential circle of the heat transfer member 10d. Note that the circle is not limited to the largest diameter among the circles tangent to the outer edge of the heat transfer member 10d. In another embodiment, a circle centered at an arbitrary point on the upper surface 24d may have a diameter that is a predetermined multiplication factor relative to the diameter of the largest diameter circle among the circles tangent to the outer edge of the heat transfer member 10d. Here, the predetermined multiplication factor is a multiplication factor of 0.5 to 1.0. Even in the heat transfer member 10d shaped as shown in FIG. 7, each fiber 24d extends spirally from the center (center of gravity 32d) of the heat transfer member 10d toward the outer edge, so that the thermal conductivity between the center of gravity 32d and each imaginary point 34d is substantially the same, and W 1~n / W ave. is close to 1. 0.8≦W 1~n / W ave. ≦1.2 n: the number of each of the multiple virtual points 34d (specifically, n=5) W 1~n : Thermal conductivity between the center of gravity 32d and each virtual point 34d W ave. : Average value of thermal conductivity between the center of gravity 32d and each virtual point 34d

[0055] According to the heat transfer member 10d having such a configuration, when the heat transfer member 10d is attached to a heat-transfer-receiving member such as a heat-generating electric or electronic component, no matter which point (so-called heat spot) on the upper surface 21d of the heat transfer member 10d is heated by the heat-transfer-receiving member, the heat transferred from the heat-transfer-receiving member is transferred along the extending direction of the fibers (i.e., the direction extending in a spiral shape from the center of gravity 32d of the heat transfer member 10d toward the outer edge so as to surround the center of gravity 32d). Therefore, the heat transfer member 10d has sufficient thermal diffusivity and can uniformly diffuse heat along a reference plane (a plane in the XY direction in FIG. 7) that is a plane parallel to the upper surface 21d of the heat transfer member 10d.

[0056] Although the above description describes an embodiment in which the heat transfer member 10d according to the modified example is composed of a plurality of fibers 24d, as another example, the heat transfer member 10d may be composed of a plurality of fiber bundles, each of which is composed of fibers 24d extending parallel to one another. In this case, the fiber bundle extends from an arbitrary point on a reference plane that is parallel to the top surface 21d of the heat transfer member 10d in a spiral shape so that the fibers 24d surround the arbitrary point toward the outer edge. Note that the arbitrary point on the reference plane may be the center of gravity of the heat transfer member 10d on the reference plane, or may be a point on the reference plane other than the center of gravity of the heat transfer member 10d.

[0057] In this heat-transfer member 10d, the space factor of each fiber is within a range of 30% to 95%. Furthermore, the thermal conductivity in a direction perpendicular to a reference plane, which is a plane parallel to the upper surface 21d of the heat-transfer member 10d (i.e., the Z direction) is within a range of 5 W / m·K to 200 W / m·K. Furthermore, the ratio of the thermal conductivity in the direction perpendicular to the reference plane (i.e., the Z direction) to the average value of the thermal conductivity between the center of gravity 32d and each imaginary point 34d in a direction parallel to the reference plane is within a range of 10 to 100.

[0058] A heat transfer member having a configuration as shown in FIG. 8 may be used as yet another embodiment of the heat transfer member. FIG. 8 is a top view of a heat transfer member 10e according to the present embodiment. In the heat transfer member 10e shown in FIG. 8, the fibers 24e are connected to each other in a single stroke on a reference plane parallel to the top surface 21e of the heat transfer member 10e, and the heat transfer member 10e has a substantially disk shape. In other words, the fibers 24e are arranged such that both ends of the fibers 24e contact or are close to each other on the reference plane to form a single path. In this heat transfer member 10e, too, the circle centered on the center of gravity 32e of the heat transfer member 10e on the top surface has the largest diameter among the circles tangent to the outer edge of the heat transfer member 10e. In other words, the circle substantially coincides with the outer circumferential circle of the heat transfer member 10e. Note that the circle is not limited to the largest diameter among the circles tangent to the outer edge of the heat transfer member 10e. In another embodiment, the diameter of a circle centered on the center of gravity 32e of the heat transfer member 10e on the upper surface 21e may be a predetermined magnification factor relative to the diameter of the largest circle among those tangent to the outer edge of the heat transfer member 10e. Here, the predetermined magnification factor is 0.5 or more and 1.0 or less. Even in the heat transfer member 10e shaped as shown in FIG. 8, the fibers 24e are arranged so that both ends of each fiber 24e are in contact with or close to each other to form a single path, so that the thermal conductivity between the center of gravity 32e and each imaginary point 34e is approximately the same, and W 1~n / W ave. is close to 1. 0.8≦W 1~n / W ave. ≦1.2 n: the number of each of the multiple virtual points 34e (specifically, n=5) W 1~n : Thermal conductivity between the center of gravity 32e and each virtual point 34e W ave. : Average value of thermal conductivity between the center of gravity 32e and each virtual point 34e

[0059] With the heat transfer member 10e having such a configuration, when the heat transfer member 10e is attached to a heat-transferred member such as a heat-generating electric or electronic component, no matter which point (so-called heat spot) on the upper surface 21e of the heat transfer member 10e is heated by the heat-transferred member, the heat transferred from the heat-transferred member is transferred along the extending direction of the fibers. This ensures sufficient thermal diffusibility in the heat transfer member 10e, and also enables the heat to be uniformly diffused along a reference plane (a plane in the XY direction in FIG. 8) that is a plane parallel to the upper surface 21e of the heat transfer member 10e.

[0060] Although the above description has been given of an embodiment in which the heat transfer member 10e according to the modified example is composed of a plurality of fibers 24e, as another example, the heat transfer member 10e may be composed of a plurality of fiber bundles, each of which is composed of fibers 24e extending parallel to one another. In this case, the fiber bundles are connected to each other in a so-called unicursal line on a reference plane that is a plane parallel to the upper surface 21e of the heat transfer member 10e.

[0061] In this heat-transfer member 10e, the space factor of each fiber is within the range of 30% to 95%. The thermal conductivity in a direction perpendicular to a reference plane, which is a plane parallel to the upper surface 21e of the heat-transfer member 10e (i.e., the Z direction) is within the range of 5 W / m·K to 200 W / m·K. The ratio of the thermal conductivity in the direction perpendicular to the reference plane (i.e., the Z direction) to the average value of the thermal conductivity between the center of gravity 32e and each imaginary point 34e in the direction parallel to the reference plane is within the range of 10 to 100.

[0062] The heat transfer member 10, 10a to 10e of this embodiment configured as described above includes a plurality of fibers 24, 24c, 24d, 24e and an upper surface 21, 21a to 21e on which a heat transfer member is placed, and each fiber 24, 24c, 24d, 24e extends along a reference plane that is a plane parallel to the upper surface 21, 21a to 21e of the heat transfer member 10, 10a to 10e. Furthermore, the fibers 24, 24c, 24d, and 24e are arranged on the reference plane so that the thermal conductivity between the center of gravity 32, 32a to 32e of the heat transfer member 10, 10a to 10e on the upper surface 21, 21a to 21e and a plurality of equally spaced imaginary points 34, 34a to 34e on the circle 30, 30a, and 30b centered on the center of gravity 32, 32a to 32e on the upper surface 21, 21a to 21e satisfies the following formula for all imaginary points 34, 34a to 34e: 0.8≦W 1~n / W ave. ≦1.2 n: the number of each of the multiple virtual points 34, 34a to 34e W 1~n : Thermal conductivity between the center of gravity 32, 32a to 32e and the virtual points 34, 34a to 34e W ave. Average value of thermal conductivity between the center of gravity 32, 32a to 32e and the virtual points 34, 34a to 34e

[0063] With such heat transfer members 10, 10a to 10e, when the heat transfer members 10, 10a to 10e are attached to a heat transfer target member such as a heat-generating electrical or electronic component, no matter which point (so-called heat spot) on the upper surface 21, 21a to 21e of the heat transfer member 10, 10a to 10e is heated by the heat transfer target member, sufficient heat diffusibility can be obtained in the heat transfer members 10, 10a to 10e, and heat can be diffused uniformly along a reference plane that is a plane parallel to the upper surface 21, 21a to 21e of the heat transfer member 10, 10a to 10e.

[0064] In the heat transfer members 10, 10a to 10e of the present embodiment, the circles 30, 30a, 30b having the centers of gravity 32, 32a to 32e on the upper surfaces 21, 21a to 21e as their centers may be the circles having the largest diameter among the circles tangent to the outer edges of the heat transfer members 10, 10a to 10e. In this case, the distance between the centers of gravity 32, 32a to 32e and the imaginary points 34, 34a to 34e can be made as large as possible, so that W 1~n / W ave. The accuracy of the value can be improved.

[0065] In the heat transfer members 10, 10a to 10e of the present embodiment, the circles 30, 30a, 30b on the upper surfaces 21, 21a to 21e, each having a center of gravity 32, 32a to 32e, may have a diameter that is a predetermined magnification of 0.5 to 1.0, which is set in advance, relative to the diameter of the largest circle among the circles that are in contact with the outer edge of the heat transfer members 10, 10a to 10e. Even in this case, since the predetermined magnification is 0.5 or more, the distance between the center of gravity 32, 32a to 32e and the imaginary points 34, 34a to 34e can be made relatively large, and therefore, W 1~n / W ave. The accuracy of the value can be improved.

[0066] Furthermore, the heat transfer members 10, 10a to 10e of the present embodiment may include fiber bundles having the fibers 24, 24c, 24d, and 24e extending parallel to one another. In this case, heat provided from the heat-transfer target member placed on the upper surface 21, 21a to 21e can be transferred along the fiber bundles having the fibers 24, 24c, 24d, and 24e extending parallel to one another.

[0067] Furthermore, in the heat transfer member 10c of the present embodiment, the fibers 24c or fiber bundles may be arranged radially on the reference plane in a direction from an arbitrary point on the reference plane toward the outer edge of the heat transfer member 10c. In this case, when the heat transfer member 10c is attached to a heat-transfer-receiving member such as a heat-generating electric or electronic component, no matter which point (a so-called heat spot) on the upper surface 21c of the heat transfer member 10c is heated by the heat-transfer-receiving member, the heat transferred from the heat-transfer-receiving member is transferred to the arbitrary point on the reference plane along the extending direction of the fibers and then radially transferred from the arbitrary point on the reference plane toward the outer edge of the heat transfer member 10c along the extending direction of the fibers. This ensures sufficient thermal diffusivity in the heat transfer member 10c and allows the heat to be uniformly diffused along the reference plane, which is a plane parallel to the upper surface 21c of the heat transfer member 10c.

[0068] In the heat transfer member 10, 10c of the present embodiment, a plurality of fiber units, each of which has fibers 24 or fiber bundles extending parallel to one another along the upper surface 21, 21c and forming a triangular prism shape, may be arranged on a reference plane so that the vertices of the fibers 24 overlap with one another, thereby allowing the fibers 24 to extend in a direction from any point on the reference plane toward the outer edge of the heat transfer member 10, 10c. Here, the extending directions of the fibers 24 of each fiber unit 20 may be different from each other. Furthermore, in this case, when the heat transfer members 10, 10c are attached to a heat transfer target member such as a heat-generating electrical or electronic component, no matter which point (so-called heat spot) on the upper surface 21, 21c of the heat transfer member 10, 10c is heated by the heat transfer target member, the heat transferred from the heat transfer target member is transferred to an arbitrary point on the reference plane along the extending direction of the fibers, and then radially transferred from this arbitrary point on the reference plane toward the outer edge of the heat transfer member 10, 10c along the extending direction of the fibers. Therefore, the heat diffusibility of the heat transfer members 10, 10c can be sufficiently obtained, and the heat can be diffused uniformly along the reference plane, which is a plane parallel to the upper surface 21, 21c of the heat transfer member 10, 10c.

[0069] Furthermore, in the heat transfer member 10d of the present embodiment, the fibers 24d or fiber bundles may be arranged to extend along a spiral shape on a reference plane. In this case, when the heat transfer member 10d is attached to a heat-transfer-receiving member such as a heat-generating electric or electronic component, no matter which point (a so-called heat spot) on the upper surface 21d of the heat transfer member 10d is heated by the heat-transfer-receiving member, the heat transferred from the heat-transfer-receiving member is transferred along the extending direction of the fibers (i.e., the direction extending in a spiral shape from the center of gravity 32d of the heat transfer member 10d toward the outer edge). This ensures sufficient thermal diffusivity in the heat transfer member 10d and allows the heat to be uniformly diffused along the reference plane, which is a plane parallel to the upper surface 21d of the heat transfer member 10d.

[0070] Furthermore, in the heat transfer member 10e of the present embodiment, the fibers 24e or fiber bundles may be arranged so that both ends of the fibers 24e or fiber bundles come into contact with or are close to each other on the reference plane to form one path. In this case, when the heat transfer member 10e is attached to a heat-transfer-receiving member such as a heat-generating electric or electronic component, no matter which point (a so-called heat spot) on the upper surface 21e of the heat transfer member 10e is heated by the heat-transfer-receiving member, the heat transferred from the heat-transfer-receiving member is transferred along the extending direction of the fibers. This ensures sufficient thermal diffusivity in the heat transfer member 10e and allows the heat to be uniformly diffused along the reference plane, which is a plane parallel to the upper surface 21e of the heat transfer member 10e.

[0071] In the heat transfer member 10, 10a to 10e of the present embodiment, the space factor of each of the fibers 24, 24c to 24e may be in the range of 30% to 95%, preferably 50% to 93%, more preferably 55% to 90%, and even more preferably 65% ​​to 90%. In this case, a space factor of each of the fibers 24, 24c to 24e of 30% or more ensures sufficient thermal conductivity in the planar direction of the heat transfer member 10 as a whole, thereby achieving uniform heat distribution in the heat transfer member 10 in a short period of time. Furthermore, a space factor of each of the fibers 24, 24c to 24e of 95% or less prevents the fibers 24, 24c to 24e from becoming too dense, thereby reducing the strength of the heat transfer member 10 and preventing breakage.

[0072] Furthermore, in the heat-transfer members 10, 10a to 10e of the present embodiment, the thermal conductivity in a direction perpendicular to the reference plane is within a range of 5 W / m·K to 200 W / m·K, preferably 5 W / m·K to 100 W / m·K, and more preferably 5 W / m·K to 60 W / m·K. In this case, since the thermal conductivity in the direction perpendicular to the reference plane is 5 W / m·K or higher, each fiber 24 arranged on every reference plane can receive and transmit heat, thereby improving the efficiency of thermal diffusion in the heat-transfer member 10. Furthermore, since the thermal conductivity in the direction perpendicular to the reference plane is 200 W / m·K or lower, excessive heat transfer in the direction perpendicular to the reference plane can be prevented, preventing a decrease in the efficiency of thermal diffusion in the reference plane. As a result, thermal diffusivity and rapid heat uniformity in the reference plane can be more sufficiently ensured.

[0073] Furthermore, in the heat-transfer member 10, 10a-10e of the present embodiment, the ratio of the thermal conductivity in a direction perpendicular to the reference plane to the average value of the thermal conductivity between the center of gravity 32, 32a-32e and each imaginary point 34, 34a-34e in a direction parallel to the reference plane may be within a range of 10 to 100. In this case, since the ratio of the thermal conductivity in a direction perpendicular to the reference plane is 10 or more, each fiber 24 arranged on any reference plane can receive and transmit heat, thereby improving the efficiency of thermal diffusion in the heat-transfer member 10. Furthermore, since the ratio of the thermal conductivity in a direction perpendicular to the reference plane is 100 or less, excessive heat transfer in the direction perpendicular to the reference plane can be prevented, thereby preventing a decrease in the efficiency of thermal diffusion in the reference plane. As a result, thermal diffusivity and rapid heat uniformity in a direction parallel to the reference plane can be more sufficiently ensured.

[0074] Furthermore, the heat-transfer members 10, 10a to 10e of the present embodiment may be configured with the fibers 24, 24c, 24d, and 24e extending along the reference plane, and the fibers 24, 24c, 24d, and 24e may be laminated in the X and Y directions. In such heat-transfer members 10, 10a to 10e, the fibers 24, 24c, 24d, and 24e can provide sufficient thermal diffusivity and can diffuse heat uniformly along the extending direction of the fibers 24, 24c, 24d, and 24e.

[0075] The heat transfer member according to the present invention is not limited to the above-described embodiment, and various modifications can be made.

[0076] For example, when fibers are arranged on the reference plane so that the thermal conductivity between the center of gravity of the heat transfer member on the upper surface of the heat transfer member and a plurality of equally spaced imaginary points on a circle centered on the center of gravity on the upper surface satisfies the following formula for all imaginary points, the configuration of the heat transfer member is not limited to those shown in Figures 1 to 8. Heat transfer members with various configurations different from those shown in Figures 1 to 8 may also be used. 0.8≦W 1~n / W ave. ≦1.2 n: Number of each of multiple virtual points W 1~n : Thermal conductivity between the center of gravity and the virtual point W ave. : Average value of thermal conductivity between the center of gravity and the virtual point

[0077] Furthermore, the fibers constituting the heat transfer member are not limited to carbon fibers, and various types of fibers other than carbon fibers can be used as the fibers constituting the heat transfer member. [Example]

[0078] The present disclosure will be described in more detail below using examples and comparative examples.

[0079] [Fabrication of Heat Transfer Member of Example 1] The heat transfer member of Example 1 was fabricated to have the configuration shown in Table 1. Specifically, the carbon fibers shown in Table 1 were packed into a Teflon (registered trademark) container (internal dimensions: 75.0 mm width, 130.0 mm length, 20.0 mm height) with the carbon fibers (Mitsubishi Chemical Corporation, pitch-based carbon fiber, fiber diameter 7 μm, thermal conductivity 810 W / m·K, cut to a fiber length of 130 mm) oriented in the longitudinal direction (i.e., parallel to each other). Then, a resin solution prepared by mixing and stirring 100 parts by mass of epoxy resin (Sanyurec Co., Ltd., SR10) with 30 parts by mass of curing agent (Sanyurec Co., Ltd., H230) was filled up to the height of the inner wall, and the carbon fibers were impregnated. The container was then placed in a constant-temperature dryer set at 60°C and left to stand for 24 hours to harden the resin solution, producing a test plate. The test plate was removed from the Teflon (registered trademark) container and cut using a band saw along the diagonal line as viewed from the top of the test plate. The cut test plate was then bonded so that each side of the cut test plate faced each other to produce an isosceles triangular prism-shaped carbon fiber unit. Five identical carbon fiber units were produced using the above-mentioned resin liquid for bonding. At this time, all carbon fibers were oriented toward the apex of the isosceles triangular prism of this carbon fiber unit. Finally, these six carbon fiber units were placed so that the apexes of the isosceles triangular prisms overlapped and bonded with the resin liquid to produce the heat transfer member of Example 1. The space factor of the carbon fiber in this heat transfer member was 70%.

[0080] [Fabrication of heat transfer members of Examples 2 to 7 and 9 to 12] Heat transfer members of Examples 2 to 7 and 9 to 12 were produced in the same manner as Example 1 so as to have the configurations shown in Table 1. The space factor of the carbon fiber in each of these heat transfer members is shown in Table 1. The alumina fiber used in Example 10 was Nitibi Alf T-5760D manufactured by Nitibi Corporation.

[0081] [Fabrication of Heat Transfer Member of Example 8] A heat transfer member of Example 8 was fabricated to have the configuration shown in Table 1. Specifically, an alumina container with multiple grooves (1 mm wide, 200 mm long, 1 mm deep) carved into the inner surface and coated with fluorine was prepared, and the carbon fibers shown in Table 1 were arranged along the grooves so that the grooves were filled with the carbon fibers. Next, a resin solution prepared by mixing and stirring 100 parts by mass of epoxy resin (SR10, manufactured by Sanyu Rec Co., Ltd.) with 30 parts by mass of a curing agent (H230, manufactured by Sanyu Rec Co., Ltd.) was filled until the carbon fibers were immersed, thereby impregnating the carbon fibers. The container was then placed in a constant temperature dryer set at 60°C and left to stand for 24 hours to cure the epoxy resin. The epoxy resin impregnated with the carbon fibers was then demolded, and carbon fiber bundles corresponding to the width of the grooves were prepared. Next, these carbon fiber bundles were aligned lengthwise and bonded together with an instant adhesive (Aron Alpha Tough Power, manufactured by Toagosei Co., Ltd.) to prepare a continuous carbon fiber bundle with a total length of 8.0 m. After winding this continuous carbon fiber bundle in a circular pattern, the end of each carbon fiber bundle was adhered to the end side of the adjacent carbon fiber bundle with instant adhesive to prepare a plate-shaped test piece. A total of 20 such test pieces were prepared. They were then stacked in a Teflon (registered trademark) container (cylindrical, internal dimensions: diameter 300.0 mm, height 20.0 mm), and the above-mentioned resin liquid was filled up to the height of the inner wall to impregnate the carbon fiber bundles. The test piece was then placed in a constant temperature dryer set at 60°C and left to stand for 24 hours to harden the epoxy resin, preparing a test plate. This test plate was removed from the Teflon (registered trademark) container to obtain the heat transfer member of Example 8. The space factor of the carbon fiber in this heat transfer member was 71%.

[0082] [Production of heat transfer member of comparative example 1] A heat transfer member of Comparative Example 1 was fabricated to have the configuration shown in Table 1. Specifically, it was fabricated using an epoxy resin filled with the carbon fiber shown in Table 1. Specifically, 220 parts by mass of carbon fiber (Mitsubishi Chemical Corporation, pitch-based carbon fiber, fiber diameter 7 μm, thermal conductivity 810 W / m·K, cut to a fiber length of 3.0 mm) shown in Table 1 were dispersed in 100 parts by mass of epoxy resin (Sanyurec Co., Ltd., SR10). Next, 30 parts by mass of a curing agent (Sanyurec Co., Ltd., H230) were added and mixed and stirred to prepare a resin liquid. This resin liquid was filled to the height of the inner wall of a Teflon (registered trademark) container (internal dimensions: 75.0 mm width, 130.0 mm length, 20.0 mm height). The resin liquid was then placed in a constant temperature dryer set at 60°C and left to stand for 24 hours. The resin liquid was then cured to prepare a test plate. The test plate was removed from the alumina container and cut using a band saw along the diagonal line as viewed from the top of the test plate. The cut test plate was then joined so that each side of the cut test plate faced each other, producing a carbon fiber unit in the shape of an isosceles triangular prism. The above-mentioned resin liquid was used for joining, and five identical carbon fiber units were produced. Finally, these six carbon fiber units were placed so that the apexes of the isosceles triangular prisms overlapped, and then joined using the resin liquid to produce the heat transfer member of Comparative Example 1. The space factor of the carbon fiber in this heat transfer member was 70%. Unlike the Examples, the carbon fibers in this heat transfer member had no regularity in the orientation of any of the X, Y, and Z directions.

[0083] (Evaluation of thermal conductivity in the surface direction) For Examples 1 to 12 and Comparative Example 1, thermal conductivity in the planar direction was evaluated. Specifically, each heat transfer member in each Example and Comparative Example was cut into a cylindrical shape (12.5 mmφ) along the planar direction to prepare a test piece (measurement sample), and the thermal conductivity of each heat transfer member was measured using a thermal conductivity measuring device (TCT716Lambda, manufactured by NETZSCH). Figures 9 to 11 show the general appearance of the heat transfer members of the Examples and Comparative Examples (see Figure 7 for a clearer appearance of the heat transfer member of Example 8). Figure 10 also shows an example of the locations (cylindrical measurement samples) cut out to measure thermal conductivity in each Example and Comparative Example. Specifically, multiple imaginary points (W) were placed on a circle (imaginary circles (a) to (c) in the figure) centered on the center of gravity of the heat transfer member. 1~5 ) were set at equal intervals, and cylindrical test pieces (measurement samples) containing each imaginary point were cut out. These measurement samples were cut out separately for each imaginary circle (a) to (c). Then, in the cut-out measurement samples, the imaginary points W on the corresponding imaginary circles (a) to (c) were 1~5 The thermal conductivity between the center of gravity and the center of gravity was measured at five equally spaced points (a total of 25 points on each imaginary circle), and these measurements were used to evaluate the thermal conductivity in the planar direction. The evaluation was performed according to the following criteria. A: The value of formula (1) is 0.95 or more and less than 1.05. B: The value of formula (1) is 0.85 or more and less than 0.95, or 1.05 or more and less than 1.15. C: The value of formula (1) is 0.80 or more and less than 0.85, or 1.15 or more and less than 1.20. D: The value of formula (1) is less than 0.80 or greater than 1.20. W 1~5 / W ave. ...Equation (1) W 1~5 : Thermal conductivity of the test piece of each example or comparative example (For example, in the case of Example 1, W1 in (a) indicates the average of the thermal conductivity at five points from the hypothetical point on the hypothetical circle (a) to the center of gravity.) W ave. :W 1~5 Average value of

[0084] (W ave.(Evaluation of the ratio of the thermal conductivity of the fiber to the For Examples 1 to 12 and Comparative Example 1, W ave. The thermal conductivity ratio of the fiber to the fiber was evaluated. That is, each heat transfer member in each example and comparative example was cut into a cylindrical shape (12.5 mmφ) along the surface direction to prepare a test piece, and the thermal conductivity of each heat transfer member was measured using a thermal conductivity measuring device (TCT716Lambda, manufactured by NETZSCH). The cut-out location was the measurement sample location of the outermost virtual circle (c) as shown in Figure 10, and the thermal conductivity was measured at five equally spaced points, and the average value of these measurements was used as the thermal conductivity value. Using this thermal conductivity value, W ave. The evaluation was based on the ratio of the thermal conductivity of the fiber to the total thermal conductivity of the fiber. The evaluation was carried out according to the following criteria. A:W ave. The ratio of the thermal conductivity of the fiber to the B:W ave. The ratio of the thermal conductivity of the fiber to the C:W ave. The ratio of the thermal conductivity of the fiber to the D:W ave. The ratio of the thermal conductivity of the fiber to the

[0085] (Evaluation of thermal conductivity in the Z-axis direction) For Examples 1 to 12 and Comparative Example 1, thermal conductivity in the Z-axis direction was evaluated. Each heat transfer member in each Example and Comparative Example was cut into a cylindrical shape (38.1 mmφ) along a direction perpendicular to the surface to prepare a test piece, and the thermal conductivity of each heat transfer member was measured using a thermal conductivity measuring device (TCT716Lambda, manufactured by NETZSCH). The test pieces were cut out at locations (a) to (e) in Figure 12, and thermal conductivity was measured at five points. These measured values ​​were used to evaluate thermal conductivity in the Z-axis direction. The evaluation was performed according to the following criteria. The thermal conductivity was calculated using the average value of the five measured values ​​at each measurement point. A: Thermal conductivity is 30W / m·K or more. B: Thermal conductivity value is 20 W / m·K or more and less than 30 W / m·K. C: Thermal conductivity value is 1 W / m·K or more and less than 20 W / m·K. D: Thermal conductivity value is less than 1 W / m·K.

[0086] (Thermal conductivity in (c) / Thermal conductivity in the Z-axis direction) The thermal conductivity was calculated from the values ​​used in the evaluation of the thermal conductivity in the imaginary circle (c) in the evaluation of the thermal conductivity in the plane direction and the evaluation of the thermal conductivity in the Z-axis direction. The evaluation was performed according to the following criteria. A: The thermal conductivity in (c) / thermal conductivity in the Z-axis direction is 25 or more. B: The thermal conductivity in (c) / thermal conductivity in the Z-axis direction is 15 or more and less than 25. C: The thermal conductivity in (c) / thermal conductivity in the Z-axis direction is 10 or more and less than 15. D: The thermal conductivity in (c) / thermal conductivity in the Z-axis direction is less than 10.

[0087] (Evaluation of thermal cycles) A thermal cycle test was conducted on Examples 1 to 12 and Comparative Example 1. Each heat transfer member was placed in a thermostatic chamber set at -55°C and left to stand for 30 minutes, then heated to 150°C at a heating rate of 10°C / min and left to stand for 30 minutes. The temperature was then lowered to -55°C at a cooling rate of 10°C / min and left to stand for 30 minutes, after which the temperature was repeatedly raised and lowered under the same conditions as above, to conduct a thermal cycle test. Evaluation was conducted according to the following criteria. A: After 400 cycles, no cracking or peeling was observed. B: Cracks and peeling were observed at 300 cycles or more but less than 400 cycles. C: Cracks and peeling were observed at 200 cycles or more but less than 300 cycles. D: Cracks and peeling were observed after less than 200 cycles.

[0088] [Table 1]

[0089] [Table 2]

[0090] [Table 3]

[0091] [Table 4] [Explanation of symbols]

[0092] 10, 10a to 10e Heat transfer member 20 Fiber Unit 21, 21a~21e top surface 23a Notch 24, 24c~24e Fiber 28 Container 30, 30a, 30b yen 32, 32a~32e Center of gravity 34, 34a~34e Virtual points

Claims

1. A plurality of fibers; a top surface on which a heat transfer target member is placed, Each of the plurality of fibers extends along a reference plane that is a plane parallel to the upper surface, a heat transfer member in which the fibers are arranged on the reference plane so that the thermal conductivity between a center of gravity of the heat transfer member on the upper surface and a plurality of imaginary points that are equally spaced on a circle on the upper surface centered on the center of gravity satisfies the following formula for all the imaginary points: 0.8≦W １～ｎ / W ａｖｅ． ≦1.2 n: the number of each of the plurality of virtual points W １～ｎ : Thermal conductivity between the center of gravity and the virtual point W ａｖｅ． : average value of thermal conductivity between the center of gravity and the virtual point

2. The heat transfer member according to claim 1 , wherein the circle centered on the center of gravity on the upper surface is the circle with the largest diameter among circles tangent to the outer edge of the heat transfer member.

3. 2. The heat transfer member according to claim 1, wherein the circle centered on the center of gravity on the upper surface has a diameter that is a predetermined multiple of the diameter of the largest circle tangent to the outer edge of the heat transfer member, the predetermined multiple being 0.5 to 1.

0.

4. The heat transfer member of claim 1 , comprising a fiber bundle with each of the fibers extending parallel to one another.

5. The heat transfer member according to claim 1 , wherein the fibers are arranged radially on the reference surface along a direction from an arbitrary point on the reference surface toward an outer edge of the heat transfer member.

6. a fiber unit in which the fibers extending parallel to each other along an upper surface are stacked, The heat transfer member according to claim 1 , wherein the side surfaces of the plurality of fiber units are in contact with each other.

7. In each of the adjacent fiber units, The heat transfer member according to claim 6 , wherein the fibers of the fiber units extend in directions different from one another.

8. The fiber unit has a plurality of fiber units each having a triangular prism shape with a vertex having the smallest angle in the direction in which the fiber extends, a heat transfer member disposed on the reference surface so that vertices of the fiber units overlap each other, The heat transfer member according to claim 6 , wherein each of the fibers is arranged to extend in a direction from an arbitrary point on the reference plane toward an outer edge of the heat transfer member.

9. The heat transfer member according to claim 1 , wherein each of the fibers is arranged to extend along a spiral on the reference surface.

10. The heat transfer member according to claim 1 , wherein the fibers are arranged on the reference surface such that both ends of the fibers are in contact with or close to each other to form one path.

11. The heat transfer member according to claim 1, wherein the space factor of each of the fibers is within a range of 30% to 95%.

12. 2. The heat transfer member according to claim 1, wherein the thermal conductivity in a direction perpendicular to the reference plane is within a range of 5 to 200 W / m·K.

13. 2. The heat transfer member according to claim 1, wherein the ratio of the thermal conductivity in a direction perpendicular to the reference plane to the average value of the thermal conductivity between the center of gravity and each of the virtual points in a direction parallel to the reference plane is within a range of 10 to 60.

14. The heat transfer member of claim 1 , wherein each of said fibers is a carbon fiber.

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