JP6870538B2 - Heat dissipation sheet - Google Patents

Description

The present invention relates to a heat radiating sheet suitable for radiating heat generated from, for example, a heat-generating electronic component to the outside.

Electronic components that generate heat by themselves, such as CPUs, may not operate properly if the temperature rises excessively. To avoid this, appropriate cooling devices are used with the electronic components. Examples of such a cooling device include a heat radiating sheet described in Patent Document 1, a heat transport device described in Patent Document 2, and a heat radiating device described in Patent Document 3.

The heat radiating sheet described in Patent Document 1 is composed of a heat conductive adhesive layer made of a matrix resin and a heat conductive filler and an expanded sheet stretched in one direction supporting the heat conductive adhesive layer. The heat transport device described in Patent Document 2 is composed of a working fluid sealed in a housing, an expanding sheet provided in the housing and forming a flow path of the working fluid, and a capillary structure. The heat radiating device described in Patent Document 3 includes a support frame made of a flexible metal sheet material having thermal conductivity and a cylindrical rhombic fin made of the same sheet material, and is provided inside the support frame. A plurality of rhombic fins are arranged in a row by connecting the ridges of the rhombic fins so that one ridge of one rhombic fin in the central portion is connected to the support frame.

Japanese Unexamined Patent Publication No. 2001-291810 Japanese Unexamined Patent Publication No. 2011-086753 Japanese Unexamined Patent Publication No. 2006-253601

In both the heat dissipation sheet described in Patent Document 1 and the heat transport device described in Patent Document 2, the expand sheet functions as a structural member such as posture holding and heat conduction that secures heat transfer or heat dissipation. It has a function as a path. As described in Patent Document 1 and Patent Document 2, the expanding sheet 10 conventionally used in this type of heat-dissipating sheet or the like is formed on a thin plate-shaped metal sheet 1 as shown in FIG. 15 (a). It is formed by making staggered cuts 2 ... at intervals of width L and stretching (expanding) the metal sheet 1 in a direction orthogonal to the direction of the cuts 2. FIG. 15B is an example of the conventional expanding sheet 10 thus formed, and by stretching the cutout 2 ... Is gradually expanded in a direction orthogonal to the forming direction of the notch 2. Due to the expansion, the portion of the notch 2 is transformed into a diamond-shaped opening 3.

The expanding sheet 10 of this form is a stretched thin plate-shaped metal sheet 1, and as shown in FIG. 15 (c) and a cross-sectional view taken along the line AA of FIG. 15 (b), the connecting portion 4 In the region, the width is twice (2L) the distance L between the adjacent cuts 2 and 2, but in the strand portion 5 between the connecting portion 4 and the connecting portion 4, the gap between the adjacent cuts is reached. It is the width of the distance L.

16 (a) is a plan view of a heat radiating sheet 20 formed by filling the opening 3 of the expanding sheet 10 with a resin material 11 as a matrix, and FIG. 16 (b) is a plan view of FIG. 16 (a). A cross-sectional view taken along the line BB, FIG. 16 (c) is a cross-sectional view taken along the line CC of FIG. 16 (a). As shown in the drawing, the entire expanding sheet 10 is embedded in the resin material 11, and the opening 3 of the expanding sheet 10 is filled with the resin material 11. In the heat radiating sheet 20 of this form, as shown in FIG. 16B, the connecting portion 4 of the heat radiating member 10 regulates the thickness S of the heat radiating sheet 20, and the upper surface 20a and the lower surface 20b of the heat radiating sheet 20. The connecting portion 4 is located so as to cover the entire area between the two. The upper end portion 4a of the connecting portion 4 is exposed to or very close to the upper surface 20a side of the heat radiating sheet 20, and the lower end portion 4b of the connecting portion 4 is exposed to the lower surface 20b side of the heat radiating sheet 20. Or they are located very close to each other.

On the other hand, as shown in FIG. 16C, since the width L of the strand portion 5 is 1/2 of the width 2L of the connecting portion 4, the upper end portion 5a of the strand portion 5U located higher in the figure is 5a. Is exposed to or very close to the upper surface 20a of the heat radiating sheet 20, but its lower end 5b is located substantially in the middle of the heat radiating sheet 20 in the thickness direction, and the lower surface 20b of the heat radiating sheet 20 is located. It has not reached the side. Further, the lower end portion 5b of the strand portion 5D located at the lower position in the figure is exposed or located very close to the lower surface 20b side of the heat radiating sheet 20, but the upper end portion 5a thereof is located in the thickness direction of the heat radiating sheet 20. It is located substantially in the middle portion and does not reach the upper surface 20a side of the heat radiating sheet 20.

Therefore, in the conventional heat radiating sheet 20 of this form, it is unavoidable that the function as a heat conduction path differs between the portion of the expanding sheet 10 where the connecting portion 4 is located and the portion where the strand portion 5 is located. As a result, when looking at the heat radiating sheet 20 as a whole, the formation of the heat conduction path by the heat radiating member 10 has to be insufficient, and in order to increase the heat conduction, the ratio of the heat radiating member 10 to the heat radiating sheet 20 can be increased. is necessary. This means that the ratio of the resin material is reduced, and the flexibility of the heat radiating sheet 20 has to be sacrificed.

The heat radiating device described in Patent Document 3 has a configuration in which a plurality of tubular rhombic fins are provided in a rectangular parallelepiped support frame, and the top plate and bottom plate which are heat radiating surfaces or heat receiving surfaces by the rhombic fins. There is an advantage that a large number of heat conduction paths of equal length are formed between the and, but the rectangular parallelepiped support frame lacks flexibility, and has a disadvantage that sufficient flexibility cannot be obtained particularly in the depth direction. Therefore, it is difficult to achieve both high thermal conductivity and the flexibility required for the heat dissipation sheet.

The present invention has been made in view of the above circumstances, and an object of the present invention is to disclose a heat radiating sheet capable of ensuring higher thermal conductivity while maintaining the required flexibility. Another object of the present invention is to disclose a method for manufacturing the heat radiating sheet.

The heat radiating sheet according to the present invention is basically a heat radiating sheet including a resin material and a heat radiating member made of a material having a higher thermal conductivity than the resin material and having a spread in a plane direction and a required thickness. As for the heat radiating member, one plane is formed by an appropriate number of heat radiating base materials bent so that the cross section on the short side of the long flat plate is composed of two parallel planes and a surface connecting the two parallel planes. The upper surface and the lower surface formed by the other plane are arranged so as to be parallel to each other, and the heat radiating member is entirely contained in the resin material except for the two parallel planes of each heat radiating base material. It is characterized by being embedded.

According to the present invention, a heat radiating sheet having high flexibility and high thermal conductivity without sacrificing flexibility is provided.

The plan view which shows an example of the original sheet used for manufacturing the heat-dissipating member used in a heat-dissipating sheet. The figure which shows an example which manufactures the heat-dissipating base material which constitutes a heat-dissipating member. The figure which shows an example of the heat dissipation base material which constitutes a heat dissipation member. A side view showing an example of a heat radiating member. The first figure explaining the process of manufacturing a heat dissipation sheet. The second figure explaining the process of manufacturing a heat dissipation sheet. The perspective view which shows the heat dissipation sheet after manufacturing. The side view which shows the heat dissipation sheet after manufacturing. The side view which shows the other embodiment of the heat dissipation sheet. FIG. 5 is a side view showing still another embodiment of the heat radiating sheet. FIG. 5 is a side view showing still another embodiment of the heat radiating sheet. FIG. 5 is a side view showing still another embodiment of the heat radiating sheet. FIG. 5 is a side view showing still another embodiment of the heat radiating sheet. The perspective view which shows the other example of a heat radiating member. The figure for demonstrating the expanded sheet which is a heat radiating member used in the conventional heat radiating sheet. The figure for demonstrating the conventional heat dissipation sheet.

An embodiment of the heat radiating sheet according to the present invention will be described with reference to the drawings.

[Heat dissipation member]
First, an example of the heat radiating member 100 used in the heat radiating sheet of this embodiment will be described together with the manufacturing process.
The heat radiating member 100 is basically configured by arranging an appropriate number of heat radiating base materials 50 having the shape shown in FIG. 3 as an example. The heat radiating base material 50 can be manufactured by any method. As an example, as shown in FIG. 1, a rectangular original sheet 50a having a spread in the plane direction is used. Examples of the material of the raw sheet 50a include metals, ceramics, graphite and the like. Examples of the metal include copper, aluminum, gold, silver, nickel, zinc, and the like. Examples of ceramics include alumina, silica, boron nitride, zinc oxide, magnesium oxide, and the like. When ceramics are used, it is preferable to mold the green sheet before firing because it is easy to mold. Preferably, they are single or composite materials having a thermal conductivity of 10 W / m · K or higher. The thickness t of the original sheet 50a is preferably 10 μm to 500 μm.

First, the original sheet 50a is cut into strips with a width w. Next, the cut long flat plate 51 is bent so that the cross section on the short side thereof is U-shaped. Specifically, as shown in FIG. 3, the bending process is performed so that the first plane 52 and the second plane 53 parallel to each other have a shape connected by the third plane 54. By this bending process, one heat radiating base material 50 is formed.

This bending process may be performed manually, but it can be performed easily and quickly by using the processing machine 60 shown in FIG. The processing machine 60 drives the first rotary roll 62 having a concave groove 61 on the peripheral surface, the second rotary roll 64 having the ridge 63 on the peripheral surface, and the two rolls 62 and 64 to apply rotational force. It consists of a mechanism (not shown in the figure). The first rotation axis O ₂ of the rotary shaft O ₁ and the second rotating roll 64 of the rotary roll 62 of are parallel, projections 63 of the second rotating roll 64 in the groove 61 of the first rotating roll 62 Is intruded. In the inserted state, a gap substantially equal to the thickness t of the original sheet 50a is formed between the concave groove 61 and the ridge 63.

The cut elongated flat plate 51 is placed between the rotating first rotating roll 62 and the second rotating roll 64 with the center of the concave groove 61 of the first rotating roll 6 in the width direction. Insert the long flat plate 51 so that the centers on the short side of the flat plate 51 coincide with each other. As a result, the long flat plate 51 is fed, and at the same time, the cross-sectional shape in the lateral direction is bent into a U shape to form the heat dissipation base material 50 shown in FIG.

In the following description, as shown in FIG. 3, the lateral direction of the first plane 52 and the second plane 53 parallel to each other is referred to as the X-axis direction, the longitudinal direction is referred to as the Y-axis direction, and the first plane 52. The direction in which the second plane 53 is separated from the second plane 53 is called the Z-axis direction. In this example, the angle α formed by the first plane 52 and the second plane 53 with the third plane 54 in the heat radiating base material 50 is 90 degrees, and the first plane 52 and the second plane 52 are both flat. The width of 53 in the X direction is both a, and the width of the third plane 54 in the Z axis direction is b. The length of the heat radiating base material 50 in the Y-axis direction is arbitrary.

As shown in FIG. 4, an appropriate number of heat radiating base materials 50 shown in FIG. 3 are arranged in the same plane in parallel with each other at a predetermined interval c to form a heat radiating member 100. The heat radiating member 100 has an upper surface 101 formed by the first flat surface 52 ... Of each heat radiating base material 50 and a lower surface 102 formed by the second flat surface 53 ..., and the upper surface 101 and the lower surface 102 are parallel to each other. The two surfaces 101 and 102 are separated by a distance b in the Z-axis direction of the third plane 54.

Although not essential, in the heat radiating member 100 shown in FIG. 4, an appropriate number of heat radiating base materials 50 are parallel to each other so that a gap 55 having a width c is formed between the adjacent heat radiating base materials 50 and 50. Is located in. The width c of the gap 55 is arbitrary, but it is practical that the width is larger than the thickness t of the original sheet 50a. Further, the width a of the first plane 52 and the second plane 53 in the X-axis direction is also arbitrary, but it is practical that a> 2t.

[Resin material 300]
By embedding the heat radiating member 100 in the resin material 300, the heat radiating sheet 200 can be obtained. The resin material 300 may be a simple substance of the resin, or may be a resin filled with a filler for improving the function. As the resin, a heat-curable resin such as a moisture-curable type, a room temperature-curable type (either a one-component type or a two-component mixed type), an epoxy resin, a urethane resin, or the like, a polyamide resin, or polyphenylene sulfide. Examples thereof include thermoplastic resins such as resins and polyimide resins. Examples of the filler include metal fillers such as copper, aluminum, silver, nickel and zinc, and inorganic fillers such as alumina, silica, boron nitride, zinc oxide, magnesium oxide and graphite. Further, a mixed material obtained by atomizing the material used for manufacturing the heat radiating member 100 and mixing it with the resin material 300 can also be used.

[Manufacturing of heat dissipation sheet 200]
The heat radiating member 100 can be embedded in the resin material 300 by any method. 5 and 6 show an example thereof. First, as shown in FIG. 5, an appropriate number of heat-dissipating base materials 50 are arranged in a mold 400 having a flat bottom surface so as to form a gap 55 parallel to each other and having a width c. As a result, the heat radiating member 100 having the shape shown in FIG. 4 is formed in the mold 400. The resin material 300 described above is poured over the resin material 300. The resin enters the internal space of the heat radiating member 100 through the gap 55. Next, as shown in FIG. 6, the mold 400 is covered with a lid 401 to adjust the height, and then the mold 400 is put into a constant temperature bath to heat-cure the resin material 300. By removing it from the mold after cooling, a heat radiating sheet 200 having a perspective view shown in FIG. 7 and a side view shown in FIG. 8 can be obtained.

[Advantages of heat dissipation sheet 200]
In the heat radiating sheet 200 of this embodiment, the first flat surface 52 of each heat radiating base material 50 constituting the heat radiating member 100 is located on the upper surface side in a wide area, and the heat radiating member 100 is formed on the lower surface side. The second plane 53 of each heat radiating base material 50 is located over a large area. The first plane 52 and the second plane 53 of each heat radiation base material 50 are connected by a third plane 54 in the overall length in the longitudinal direction (Y-axis direction). Therefore, heat transfer at the interface with the adherend (heating element or the like) can be efficiently performed, and the thermal resistance in practical use can be reduced. Further, the third plane 54 forms a heat conduction path that is not interrupted in the thickness direction (Z-axis direction). Thereby, thermal conductivity is achieved. Further, the heat radiating sheet 200 of this form is provided with a gap 55 having the distance c extending in the Y-axis direction, and can be flexibly deformed in the surface direction along the X-axis.

In addition, in order to improve the filling property of the resin material 300 described above, an adherend (heating element, etc.) may be applied to the entire long flat plate 51 forming the heat radiating base material 50 or to an appropriate portion. It is also possible to form a small hole having a diameter of about 0.05 mm so as not to significantly hinder the contact area with, for example, about 1 vol% or less of the whole.

[Other configurations of heat dissipation sheet]
The volume fraction occupied by the heat radiating member 100 with respect to the total volume of the heat radiating sheet 200 is not particularly limited, but is preferably 5% or more and 80% or less. If it is less than 5%, the thermal conductivity cannot be increased and it is not useful as a heat radiating material. In addition, the area that does not contribute to heat dissipation becomes wider, and the heat transfer unevenness in the heat dissipation sheet increases, so there is a possibility that an unexpectedly high temperature part may be formed in the product. If it exceeds 80%, the heat radiating sheet has a high thermal conductivity, but it may become too hard and the interfacial thermal resistance with the product becomes large, so that the desired heat radiating performance cannot be obtained.

The ratio of the thickness of the original sheet 50a forming the heat radiating base material 50 to the thickness of the heat radiating sheet 200 is preferably 1: 3 or more and 1:10 or less. If it is less than 1: 3, the flexibility of the heat radiating member in the thickness direction with respect to compressive stress is lowered, and the flexibility of the heat radiating sheet is impaired, so that the interfacial thermal resistance with the product is increased and the desired heat radiating performance is obtained. There is a risk that it will not be possible. If it exceeds 1:10, the volume fraction of the heat radiating member cannot be increased, and high thermal conductivity cannot be achieved.

[Other Embodiment-1]
FIG. 9 shows another embodiment of the heat dissipation sheet. The heat radiating sheet 200a is different from the above-mentioned insulating sheet 200 in that the heat radiating sheet 100 is provided with the insulating layers 103 on the front and back surfaces. Other configurations are the same as the heat radiating sheet 200. The material of the insulating layer 103 includes a heat-curable resin such as silicone resin, epoxy resin, urethane resin, a resin material such as polyamide resin, polyphenylene sulfide resin, and polyimide resin, or alumina, silica, boron nitride, and the like. Materials such as ceramics materials can be used. By providing the insulating layer 103, a heat radiating sheet 200a having both high thermal conductivity and insulating properties can be obtained.

[Other Embodiment-2]
FIG. 10 shows still another embodiment of the heat dissipation sheet. The heat radiating sheet 200b is different from the above-mentioned insulating sheet 200 in that the heat radiating member 100 is formed by using the heat radiating base material 50 having the insulating film 104 on the front and back surfaces. Other configurations are the same as the heat radiating sheet 200. As the material of the insulating film 104, a thermosetting resin such as silicone resin, epoxy resin, urethane resin, or the like, a resin material such as polyamide resin, polyphenylene sulfide resin, or polyimide resin, or alumina, silica, boron nitride, etc. Materials such as ceramics materials can be used. Even in this insulating sheet 200b, since the heat radiating member 100 itself has an insulating performance, both high thermal conductivity and insulating properties can be ensured.

[Other Embodiment-3]
FIG. 11 shows yet another embodiment of the heat dissipation sheet. In this heat radiating sheet 200c, as the heat radiating member 100c, the heat radiating base material 50 described with reference to FIG. 3 is not oriented in the same direction, but the two heat radiating base materials 50 face each other on the third planes 54 and 54. It differs from the above-mentioned heat-dissipating sheet 200 in that it uses a heat-dissipating member 100c having a structure in which a heat-dissipating base material set 50k is arranged in parallel and an appropriate number of the heat-dissipating base materials are arranged in parallel at intervals c. In the heat radiating base material set 50k, the two third planes 54, 54 facing each other may be in close contact with each other or may have a gap c.

[Other Embodiment-4]
FIG. 12 shows still another embodiment of the heat dissipation sheet. As the heat radiating member, the heat radiating sheet 200d is not the heat radiating base material 50 having a U-shaped cross section shown in FIG. It differs from the above-mentioned heat-dissipating sheet 200 in that it uses a heat-dissipating member 100d formed by arranging an appropriate number of heat-dissipating base materials 50d that are bent in opposite directions in parallel with each other. As shown, in the adjacent heat radiation base material 50d, between the tip of the first plane 52 of one heat radiation base material 50d and the third plane 54 of the other heat radiation base material 50d, and one of the heat dissipation base materials. It is preferable to arrange the heat radiating base materials 50 in parallel so that a gap c is formed between the tip of the second plane 53 of the base material 50d and the third plane 54 of the other heat radiating base material 50d. It is an aspect.

[Other Embodiment-5]
FIG. 13 shows still another embodiment of the heat dissipation sheet. The heat radiating sheet 200e uses a heat radiating member 100e in which an appropriate number of heat radiating base materials 50e whose third plane 54 is not a vertical plane but a slope is used as the heat radiating member 50e. , It is different from the heat dissipation sheet 200 described above. In the illustrated example, the right end of the first plane 52 and the left end of the second plane 53 are connected to the inclined third plane 54, but the first plane 52 of the heat radiating base material 50e which is a slope is connected. The connection portion between the surface and the second plane 53 is not limited to this, and is arbitrary.

[Other Embodiment-6]
FIG. 14 shows still another form of the heat radiating member 100. Here, as the heat radiating base material 50f, the first slit 56 extending from the first plane 52 to the third plane 54 and the third plane 54 with respect to the heat radiating base material 50 described with reference to FIG. A heat-dissipating base material 50f in which an appropriate number of second slits 57 extending from the second plane 53 to the second plane 53 are formed so as to be orthogonal to the Y-axis direction and at appropriate intervals in the Y-axis direction. Is used.

As shown in FIG. 14, the heat radiating member 100f is formed by arranging an appropriate number of heat radiating base materials 50f in parallel with each other and at regular intervals c. When the heat radiating sheet 200 is manufactured in the same manner as shown in FIGS. 5 and 6 using the heat radiating member 100f having this configuration, the manufactured heat radiating sheet 200 is produced in two directions, the X-axis direction and the Y-axis direction. It will be highly flexible.

The heat radiating base material 50f of this form is formed by cutting a long flat plate 51 having a width a from the original sheet 50a, or with respect to the long flat plate 51 after cutting out. A notch corresponding to the first slit 56 and the second flat surface 53 is formed at a predetermined distance from the left and right long sides, and the long flat plate 51 after the notch is formed is bent. And can be easily formed.

Hereinafter, the superiority of the heat radiating sheet 200 according to the present invention will be described with reference to Examples and Comparative Examples.

[Example product]
A pure Cu foil having a thickness of 0.03 mm was used as the raw sheet 50a of the heat radiating base material 50. Using the original sheet 50a, a heat radiating base material 50f having a width M and a first slit 56 and a second slit 57 shown in FIG. 14 was produced. However, as the heat radiating base material 50f, three types of heat radiating base materials 50f were prepared by changing the width a of the first plane 52 and the second plane 53 in the X-axis direction. Examples 1 to 3 in which the heat-dissipating base materials 50f are arranged in parallel with each other as shown in FIG. 14 and the volume fractions of the heat-dissipating members 100f are different in the same manner as shown in FIGS. 5 and 6. The heat dissipation sheet 200 of the above was produced. As the resin material 300, a liquid silicone resin was used, embedded in the resin, and then heat-cured in a constant temperature bath to obtain a heat radiating sheet 200. Specific dimensions are shown in Examples 1 to 3 in Table 1. The silicone resin used was KE-1870 (addition reaction type) manufactured by Shin-Etsu Chemical Co., Ltd., and the curing conditions were 150 ° C. × 30 minutes, viscosity 400 mPa · s, and hardness after curing 15 (durometer A).

[Comparative example product]
Using the same material, the heat radiating member 10 was produced by the conventional method described above based on FIGS. 15 and 16. At the time of producing the heat radiating member 10, the stretching amount was changed, and the heat radiating sheets of Comparative Examples 1 and 2 shown in Table 1 having different volume fractions of the heat radiating member (Cu) were produced. The tilt angle of Comparative Examples 1 and 2 is the tilt angle A ° shown in FIG. 16B.

[Characteristic test]
The thermal conductivity and thermal resistance of Examples 1 to 3 and Comparative Examples 1 and 2 were measured by a steady-state method. The results are shown in Table 1.

［注１］傾斜角度αは、図１４に示した放熱基材５０ｆでの折り曲げ角度α、但し、比較例での傾斜角度αは、図１６（ｂ）での角度Ａ°、
［注２］幅ａは、図１１に示した放熱基材５０ｆでのＸ軸方向の幅ａ、
［注３］隙間ｃは、図１４に示した放熱部材１０ｆでの隙間ｃ、Ｍは図１４に示した放熱基材５０ｆでの第１のスリット５６および第２のスリット５７の幅、
［注４］熱伝導率は放熱シート単体での放熱性能であり、熱抵抗は部材に挟まれた実用時を想定した放熱性能である。作製した放熱シートを所定のサイズ（φ２０ｍｍ）にカットし、定常法で測定した。

[Note 1] The tilt angle α is the bending angle α of the heat radiating base material 50f shown in FIG. 14, but the tilt angle α in the comparative example is the angle A ° in FIG. 16 (b).
[Note 2] The width a is the width a in the X-axis direction of the heat radiating base material 50f shown in FIG.
[Note 3] The gap c is the gap c in the heat radiating member 10f shown in FIG. 14, and M is the width of the first slit 56 and the second slit 57 in the heat radiating base material 50f shown in FIG.
[Note 4] The thermal conductivity is the heat dissipation performance of the heat dissipation sheet alone, and the thermal resistance is the heat dissipation performance assuming practical use sandwiched between members. The prepared heat dissipation sheet was cut into a predetermined size (φ20 mm) and measured by a steady method.

[Evaluation]
In the example product and the comparative example product, the finished thickness is equal to 0.3 mm, and the volume fraction of the heat radiating member and the resin is almost the same, but the example product is compared with the comparative example product. , Thermal conductivity is greatly improved. Further, the thermal resistance of the example product is smaller than that of the comparative example product. This is a result that the heat radiating member used in this embodiment basically has the shape shown in FIG. 7, and as a result, the heat conduction path is substantially increased as compared with the comparative example product. is there.

50a ... Original sheet,
50 ... Heat dissipation base material,
51 ... Long flat plate,
52 ... First plane,
53 ... Second plane,
54 ... Third plane,
55 ... Gap between heat dissipation base materials,
60 ... Processing machine,
61 ... concave groove,
62 ... First rotary roll,
63 ... Convex,
64 ... Second rotating roll,
100 ... Heat dissipation member,
101 ... The upper surface of the heat radiating member,
102 ... The lower surface of the heat dissipation member,
200 ... Heat dissipation sheet,
300 ... Resin material,
400 ... Mold.

Claims (1)

A heat-dissipating sheet including a resin material and a heat-dissipating member made of a material having a higher thermal conductivity than the resin material and having a spread in the plane direction and a required thickness.
The heat dissipation member is elongated in the short sides of the flat cross section is the so folded heat radiation substrate composed of two parallel first and second planes third flat surface connecting between An appropriate number of the first and second planes are arranged so that the upper surface formed by one plane and the lower surface formed by the other plane are parallel to each other.
The heat radiating member is entirely embedded in the resin material except for the first and second planes of each heat radiating base material.
The heat radiating base material includes a first slit extending from the first plane to the third plane and a second slit extending from the third plane to the second plane of the heat radiating base material. A heat-dissipating sheet characterized in that it is formed alternately along the longitudinal direction.

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