JP2014033130A - Thermally conductive electromagnetic wave shield sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermally conductive electromagnetic wave shield sheet in which shielding of electromagnetic waves and thermal conductivity are enhanced.SOLUTION: A thermally conductive electromagnetic wave shield sheet for dissipating heat generated from an electronic component 15 to a housing 16 while shielding electromagnetic waves entering the electronic component 15 or exiting therefrom includes a conductive layer 13 adhering to the surface of the electronic component, and a heat conduction layer 12 laminated on the conductive layer 13 so as to sandwich the conductive layer 13 therebetween. Since the conductive layer 13 adheres to the surface of the electronic component 15, no gap occurs between the surface of the electronic component 15 and the conductive layer 13, and electromagnetic waves entering the electronic component 15 or exiting therefrom can be shielded surely by the conductive layer 13. Furthermore, since the heat conduction layer 12 has an Asker C hardness of 30 or less, it can be applied tightly to the housing 16 while following the shape thereof, and thereby heat dissipation by the heat conduction layer 12 can be enhanced furthermore.

Description

  The present invention relates to a thermally conductive electromagnetic shielding sheet that shields (shields) electromagnetic waves entering and exiting an electronic component inside the housing and radiates heat generated by the electronic component to the housing by thermal conduction. The present invention relates to a technique for further improving electromagnetic shielding properties and thermal conductivity.

  2. Description of the Related Art Conventionally, a heat conductive electromagnetic wave shielding sheet configured by sequentially laminating a heat conductive layer and a conductive layer has been proposed. For example, as shown in FIG. 3, the thermally conductive electromagnetic wave shield sheet described in Patent Document 1 below has a structure in which a conductive layer 2 and an insulating layer 3 are sequentially stacked on a thermally conductive layer 1.

  When the heat conductive electromagnetic shielding sheet configured as described above is mounted between the surface of an electronic component 5 such as an IC provided on the substrate 4 and a sheet metal 6 such as a housing of an electronic device, the conductive layer 2 is not in direct contact with the sheet metal 6 and is electrically isolated with the insulating layer 3 interposed therebetween. For this reason, the conductive layer 2 and the sheet metal 6 act as two conductors independent of electromagnetic waves, and can shield (shield) the electromagnetic waves satisfactorily.

Japanese Patent No. 4798629

  By the way, in the conventional heat conductive electromagnetic wave shielding sheet shown in FIG. 3, the heat conductive layer 1 is interposed between the surface of the electronic component 5 and the conductive layer 2. Thereby, since the conductive layer 2 is separated from the surface of the electronic component 5 by the thickness of the heat conductive layer 1, there remains room for further enhancing the function of shielding (shielding) electromagnetic waves entering and exiting the electronic component 5.

  In the conventional heat conductive electromagnetic wave shield sheet shown in FIG. 3, the conductive layer 2 and the insulating layer 3 are interposed between the heat conductive layer 1 and the sheet metal 6. As a result, there remains room for further improving the heat dissipation characteristics by heat conduction from the heat conductive layer 1 to the sheet metal 6.

  Then, the objective of this invention is providing the heat conductive electromagnetic wave shield sheet which improved electromagnetic wave shielding property and thermal conductivity more.

  The present invention that solves the above-described problems is a thermally conductive electromagnetic wave shielding sheet that radiates heat generated by the electronic component while shielding electromagnetic waves entering and exiting the electronic component inside the housing, on the surface of the electronic component. It is characterized by comprising a conductive layer that is in close contact and a heat conductive layer that is in close contact with the surface of the housing and is laminated on the conductive layer.

  The heat conductive layer has an Asker C hardness of 30 or less.

Further, the heat conductive layer is characterized in that a stress at the time of compression of 20 to 40% is 100 N / 100 mm ² or less.

  In addition, the present invention provides a method for producing a thermally conductive electromagnetic wave shielding sheet according to any one of claims 1 to 3, wherein the thermal conductive layer is laminated on the surface of a release sheet, and then the thermal conductive layer The conductive layer is laminated on the surface.

That is, in the heat conductive electromagnetic wave shielding sheet of the present invention, the conductive layer is in close contact with the surface of the electronic component, so that no gap is generated between the surface of the electronic component and the conductive layer. Thereby, the electromagnetic waves entering and exiting the electronic component can be reliably shielded (shielded) by the conductive layer.

Further, when the hardness of the heat conduction layer is set to 30 or less in Asker C hardness, the heat conduction layer can be securely adhered to the surface of the housing while following the shape of the housing covering the electronic component.
When the housing is mounted on the electronic device, the housing presses the conductive layer against the surface of the electronic component via the heat conductive layer. At this time, since the heat conductive layer adheres closely to the shape of the housing, the conductive layer can be pressed against the surface of the electronic component with uniform pressure. The shielding property of electromagnetic waves can be improved by closely contacting.

Furthermore, when the stress at the time of 20-40% compression in a heat conductive layer shall be 100 N / 100mm < ² > or less, when a heat conductive layer presses a conductive layer toward the surface of an electronic component, a non-uniform tensile force is applied to a conductive layer. Does not act on. Thereby, when a conductive layer is comprised from metal foil, it can prevent reliably that the metal foil pressed toward the surface of an electronic component is partially damaged.

  Furthermore, since the heat conductive electromagnetic wave shielding sheet of the present invention is manufactured by sequentially laminating a heat conductive layer and a conductive layer on a single release sheet, the heat conduction laminated on the first release sheet. Compared to the conventional manufacturing method in which the layer and the conductive layer laminated on the second release sheet are closely adhered to each other, the number of release sheets used is reduced and the manufacturing cost of the heat conductive electromagnetic shielding sheet is reduced. can do.

  ADVANTAGE OF THE INVENTION According to this invention, the heat conductive electromagnetic wave shield sheet which improved electromagnetic wave shielding property and thermal conductivity more can be provided.

Sectional drawing which shows the structure of the heat conductive electromagnetic wave shield sheet of this invention. Sectional drawing which shows the state which mounted | wore between the electronic component and the housing | casing between the heat conductive electromagnetic shielding sheet shown in FIG. Sectional drawing which shows the structure of the heat conductive electromagnetic wave shield sheet described in the patent 4798629 specification.

  Hereinafter, with reference to FIG. 1 and FIG. 2, one embodiment of the heat conductive electromagnetic wave shield sheet of this invention is described in detail.

  As shown in FIG. 1, the thermally conductive electromagnetic wave shielding sheet 10 of the present embodiment is laminated on the surface of the release sheet 11 and on the surface of the thermally conductive layer 12. And a conductive layer 13.

  The heat conductive layer 12 can be formed by filling a flexible material such as silicon rubber with a heat conductive filler such as soft ferrite.

  The conductive layer 13 can be formed of a foil made of a metal such as copper or aluminum. In addition, it can also be comprised by the sheet | seat which mixed electrically conductive materials, such as silver and carbon, into the magnetic foil which consists of an electroconductive magnetic material, or silicon rubber.

The heat conductive layer 12 is laminated on the surface of the release sheet 11 by the self-adhesiveness (tack property) of the heat conductive layer 12. Similarly, the conductive layer 13 is laminated on the surface of the heat conductive layer 12 by the self-adhesiveness (tack property) of the heat conductive layer 12.
Thereby, since the heat conductive electromagnetic wave shield sheet 10 can be manufactured by laminating the heat conductive layer 12 and the conductive layer 13 using only one release sheet 11, the number of the release sheets 11 used can be reduced. The manufacturing cost of the conductive electromagnetic wave shielding sheet 10 can be reduced.

  On the other hand, as shown in FIG. 2, after releasing the release sheet 11 to expose the surface of the heat conductive layer 12, the back surface of the casing 16 covering the electronic component 15 such as an IC provided on the substrate 14 is formed. When the housing 16 is attached to the electronic device and the electronic component 15 is covered by the attachment, the conductive layer 13 can be brought into close contact with the surface of the electronic component 15.

At this time, the hardness of the heat conductive layer is preferably 30 or less in terms of Asker C hardness. When this value is 30 or less, the heat conductive layer 12 can be reliably adhered to the back surface of the housing 16 while following the shape of the housing 16 covering the electronic component 15.
When the housing 16 is attached to the electronic device, the housing 16 presses the conductive layer 13 against the surface of the electronic component 15 via the heat conductive layer 12.
At this time, since the heat conductive layer 12 adheres following the shape of the housing 16, the conductive layer 13 can be pressed against the surface of the electronic component with a uniform pressure. It is possible to improve the shielding property of electromagnetic waves by securely adhering to the surface.

Moreover, it is preferable that the stress at the time of 20-40% compression in a heat conductive layer is 100 N / 100mm < ² > or less. When this value is 100 N / 100 mm ² or less, when the heat conductive layer 12 presses the conductive layer 13 toward the surface of the electronic component 15, a non-uniform tensile force does not act on the conductive layer 13.
As a result, when the conductive layer 13 made of the metal foil is pressed toward the surface of the electronic component 15, an excessive tensile force acts on a part of the metal foil from the heat conductive layer 12 to break the metal foil. Can be surely prevented.

  As is clear from the above description, in the thermally conductive electromagnetic wave shielding sheet 10 of the present embodiment, the conductive layer 13 is in close contact with the surface of the electronic component 15, and therefore, between the surface of the electronic component 15 and the conductive layer 13. The electromagnetic wave entering and exiting the electronic component 15 can be reliably shielded (shielded) by the conductive layer 13 without generating a gap.

  In addition, heat generated in the electronic component 15 is transmitted to the heat conductive layer 12 through the conductive layer 13 which is a metal foil having excellent heat conductivity, and the heat conductive layer 12 in close contact with the housing 16 is transferred to the heat conductive layer 12. Therefore, the electronic component 15 can be efficiently cooled.

As mentioned above, although the heat conductive electromagnetic wave shield sheet of this invention was demonstrated in detail, it cannot be overemphasized that this invention is not limited by embodiment mentioned above and a various change is possible.
For example, the heat conductive electromagnetic wave shielding sheet 10 of the above-described embodiment is formed by laminating the heat conductive layer 12 and the conductive layer 13 on the surface of the release sheet 11 using the self-adhesive property (tack property) of the heat conductive layer 12. However, they can be adhered to each other using an appropriate pressure-sensitive adhesive or adhesive.

DESCRIPTION OF SYMBOLS 1 Thermal conductive layer 2 Conductive layer 3 Insulating layer 4 Substrate 5 Electronic component 10 Thermally conductive electromagnetic wave shield sheet 11 Release sheet 12 Thermal conductive layer 13 Conductive layer 14 Substrate 15 Electronic component 16 Housing

Claims (4)

A heat conductive electromagnetic wave shielding sheet for radiating heat generated by the electronic component to the housing while shielding electromagnetic waves entering and exiting the electronic component inside the housing,
A conductive layer in close contact with the surface of the electronic component;
A heat conductive layer laminated on the conductive layer, which is in close contact with the surface of the housing;
A thermally conductive electromagnetic wave shielding sheet comprising: The heat conductive electromagnetic wave shielding sheet, wherein the heat conductive layer has an Asker C hardness of 30 or less. The heat conductive electromagnetic wave shielding sheet according to claim 1 or 2, wherein the heat conductive layer has a stress at the time of compression of 20 to 40% of 100 N / 100 mm ² or less. It is a manufacturing method of the heat conductive electromagnetic wave shield sheet according to any one of claims 1 to 3,
A method for producing a thermally conductive electromagnetic wave shielding sheet, comprising: laminating the heat conductive layer on a surface of a release sheet, and then laminating the conductive layer on a surface of the heat conductive layer.

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