阅读说明：本技术 电磁波吸收复合板 (Electromagnetic wave absorption composite board ) 是由 加川清二 于 2019-04-08 设计创作，主要内容包括：一种电磁波吸收复合板,其包括层压在电磁波吸收膜上的电磁波屏蔽膜；所述电磁波吸收膜包括形成在塑料膜的表面上的单层或多层金属薄膜；所述金属薄膜具有在多个方向上具有不规则宽度和间隔的大量(多个)基本平行的不连续线性划痕；所述电磁波屏蔽膜是导电金属箔、具有导电金属薄膜或涂层的塑料膜,或碳板；并且电磁波屏蔽膜与电磁波吸收膜的面积比为10-80％。(An electromagnetic wave absorbing composite panel comprising an electromagnetic wave shielding film laminated on an electromagnetic wave absorbing film; the electromagnetic wave absorption film includes a single-layer or multi-layer metal thin film formed on a surface of a plastic film; the metal film has a plurality of substantially parallel discontinuous linear scratches(s) having irregular widths and intervals in a plurality of directions; the electromagnetic wave shielding film is a conductive metal foil, a plastic film with a conductive metal film or coating, or a carbon plate; and the area ratio of the electromagnetic wave-shielding film to the electromagnetic wave-absorbing film is 10-80%.)

1. An electromagnetic wave absorbing composite panel comprising an electromagnetic wave absorbing film and an electromagnetic wave shielding film laminated on the electromagnetic wave absorbing film;

the electromagnetic wave absorption film has a single-layer or multi-layer metal thin film formed on a surface of a plastic film; the metal film has a plurality of substantially parallel discontinuous linear scratches(s) having irregular widths and intervals in a plurality of directions; and is

The area ratio of the electromagnetic wave-shielding film to the electromagnetic wave-absorbing film is 10-80%.

2. The electromagnetic wave absorbing composite panel according to claim 1, wherein the area ratio of the electromagnetic wave-shielding film to the electromagnetic wave-absorbing film is 20 to 80%.

3. The electromagnetic wave absorbing composite panel according to claim 2, wherein the area ratio of the electromagnetic wave-shielding film to the electromagnetic wave-absorbing film is 30-70%.

4. The electromagnetic wave absorbing composite panel according to claim 1, wherein the electromagnetic wave-shielding film is a conductive metal foil; a plastic film having a conductive metal film or coating; or a carbon plate.

5. The electromagnetic wave absorbing composite panel as set forth in claim 1, wherein 90% or more of the linear scratches in the electromagnetic wave absorbing film have a width in the range of 0.1 μm to 100 μm and an average of 1 μm to 50 μm, and a lateral spacing in the range of 1 μm to 500 μm and an average of 1 μm to 200 μm.

6. The electromagnetic wave absorbing composite panel according to claim 1, wherein the linear scratches in the electromagnetic wave absorbing film have an acute intersection angle θ s in the range of 30-90 °.

7. The electromagnetic wave absorbing composite panel according to claim 4, wherein the conductive metal in the electromagnetic wave-shielding film is at least one selected from the group consisting of aluminum, copper, silver, tin, nickel, cobalt, chromium, and alloys thereof.

8. The electromagnetic wave absorbing composite panel according to any one of claims 1 to 7, wherein the electromagnetic wave absorbing film and the electromagnetic wave shielding film are both rectangular or square.

Technical Field

The present invention relates to an electromagnetic wave absorbing composite panel which has a high absorbing ability for electromagnetic wave noise in a desired frequency range and is capable of transforming a frequency range in which the electromagnetic wave noise absorbing ability is maximized.

Background

Electric and electronic appliances emit electromagnetic wave noise, and the intrusion of ambient electromagnetic wave noise into them causes noise to be contained in the signal. In order to prevent the emission and intrusion of electromagnetic wave noise, electric and electronic appliances are generally shielded with a metal plate. It has also been proposed to provide an electromagnetic wave absorption film in electric and electronic appliances to absorb electromagnetic wave noise.

For example, WO 2010/093027 a1 discloses a metal film-plastic composite film having linear scratches with reduced anisotropy in electromagnetic wave absorption capacity, which includes a plastic film and a single-layer or multi-layer metal film formed on at least one surface of the plastic film, the metal film having a large number of substantially parallel discontinuous linear scratches with irregular widths and intervals in a plurality of directions. WO 2010/093027 a1 describes that a linearly scratched metal film-plastic composite film can be laminated with an electromagnetic wave reflector (metal plate, mesh or net, plastic film with metal film, etc.) through a dielectric layer to obtain a composite electromagnetic wave absorber. The composite electromagnetic wave absorber has a high absorption capability for broadband electromagnetic wave noise, but does not have a function of exhibiting a particularly large absorption capability for electromagnetic wave noise in a specific frequency range, nor a function of frequency range conversion for maximizing the electromagnetic wave absorption capability.

WO 2013/081043 a1 discloses an electromagnetic wave absorbing composite panel comprising (a) a first electromagnetic wave absorbing film comprising a plastic film, and a single-layer or multi-layer metal thin film formed on at least one surface of the plastic film, the metal thin film having substantially parallel discontinuous linear scratches with irregular widths and intervals in a plurality of directions; and (b) a second electromagnetic wave absorption film made of resin or rubber in which magnetic and non-magnetic particles are dispersed. The electromagnetic wave absorbing composite sheet has a high ability to absorb electromagnetic wave noise at a wide frequency, but does not have a function of exhibiting a particularly large ability to absorb electromagnetic wave noise in a specific frequency range, and a function of frequency range conversion for maximizing the electromagnetic wave absorbing ability.

Disclosure of Invention

Object of the Invention

Accordingly, an object of the present invention is to provide an electromagnetic wave absorbing composite panel having high absorbing ability to electromagnetic wave noise in a desired frequency range and capable of transforming a frequency range in which the electromagnetic wave noise absorbing ability is maximized.

As a result of intensive studies with respect to the above objects, the inventors found that an electromagnetic wave absorbing composite panel having high absorption capability for electromagnetic wave noise in a desired frequency range and capable of shifting a frequency range in which the electromagnetic wave noise absorption capability is maximized can be obtained by laminating an electromagnetic wave shielding film on an electromagnetic wave absorbing film having a thin metal film with a large number (a plurality) of substantially parallel discontinuous linear scratches having irregular widths and intervals in a plurality of directions and setting an area ratio of the electromagnetic wave shielding film to the electromagnetic wave absorbing film to 10 to 80%. The present invention has been completed based on such findings.

Accordingly, the electromagnetic wave absorbing composite panel of the present invention includes an electromagnetic wave absorbing film and an electromagnetic wave shielding film laminated on the electromagnetic wave absorbing film;

the electromagnetic wave absorption film includes a single-layer or multi-layer metal thin film formed on a surface of a plastic film, the metal thin film having a plurality of (a plurality of) substantially parallel discontinuous linear scratches having irregular widths and intervals in a plurality of directions; and is

The area ratio of the electromagnetic wave-shielding film to the electromagnetic wave-absorbing film is 10 to 80%.

The area ratio of the electromagnetic wave-shielding film to the electromagnetic wave-absorbing film is preferably 20 to 80%, more preferably 30 to 70%, and most preferably 40 to 60%.

The electromagnetic wave shielding film is preferably a conductive metal foil; a plastic film having a conductive metal film or coating; or a carbon plate.

The width of 90% or more of the linear scratches in the electro-magnetic wave absorption film is preferably in the range of 0.1 μm to 100 μm and is 1 μm to 50 μm on average, and the lateral spacing is in the range of 1 μm to 500 μm and is 1 μm to 200 μm on average.

The linear scratches in the electro-magnetic wave absorption film preferably have an acute intersection angle thetas in the range of 30-90 deg..

The conductive metal in the electromagnetic wave-shielding film is preferably at least one selected from the group consisting of aluminum, copper, silver, tin, nickel, cobalt, chromium, and alloys thereof.

The electromagnetic wave absorption film and the electromagnetic wave shielding film are preferably both rectangular or square.

Drawings

Fig. 1(a) is an exploded plan view showing an example of the electromagnetic wave absorbing composite panel of the present invention.

Fig. 1(b) is a plan view showing an example of the electromagnetic wave-absorbing composite panel of the present invention.

Fig. 2(a) is a cross-sectional view showing an example of an electromagnetic wave absorption film constituting the electromagnetic wave absorption composite panel of the present invention.

Fig. 2(b) is a partial plan view showing an example of a linear scratch of the electromagnetic wave absorption film.

Fig. 2(c) is a cross-sectional view taken along line a-a in fig. 2 (b).

Fig. 2(d) is an enlarged cross-sectional view showing a portion B in fig. 2 (c).

Fig. 2(e) is a cross-sectional view showing another example of the electromagnetic wave absorption film.

Fig. 2(f) shows an enlarged cross-sectional view of a portion C in fig. 2 (e).

Fig. 3(a) shows a perspective view of an example of an apparatus for forming a linear scratch.

Fig. 3(b) is a plan view showing the device of fig. 3 (a).

Fig. 3(c) is a cross-sectional view taken along line B-B in fig. 3 (B).

Fig. 3(d) is an enlarged partial plan view showing the principle of forming a linear scratch inclined with respect to the moving direction of the composite film.

Fig. 3(e) is a partial plan view showing the inclination angle of the pattern roll and the push roll to the composite film in the apparatus of fig. 3 (a).

Fig. 4 is a partial cross-sectional view showing an apparatus for forming a linear scratch.

Fig. 5 is a perspective view showing another example of the apparatus for forming a linear scratch.

Fig. 6(a) is a plan view showing another example of the electromagnetic wave-absorbing composite panel of the present invention.

Fig. 6(b) is a plan view showing still another example of the electromagnetic wave-absorbing composite panel of the present invention.

Fig. 7(a) is a plan view showing a system for measuring the power of reflected and transmitted waves to an incident wave.

Fig. 7(b) is a schematic partial cross-sectional view showing the system of fig. 7 (a).

Fig. 8 is a plan view showing an example of a sample placed on the microstrip line MSL.

Fig. 9 is a graph showing the noise absorption ratio P of sample 1 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 90 °, and the area ratio of the aluminum foil is 0%) (the cross angle θ s of the linear scratches is 90 °, the area ratio of the aluminum foil is 0%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 10 is a graph showing the noise absorption ratio P of sample 2 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 90 °, and the area ratio of the aluminum foil is 20%) (the cross angle θ s of the linear scratches is 90 °)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 11 is a graph showing the noise absorption ratio P of sample 3 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 90 °, and the area ratio of the aluminum foil is 40%) (the cross angle θ s of the linear scratches is 90 °, the area ratio of the aluminum foil is 40%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 12 is a graph showing the noise absorption ratio P of sample 4 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 90 °, and the area ratio of the aluminum foil is 50%) (the cross angle θ s of the linear scratches is 90 °, the area ratio of the aluminum foil is 50%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 13 is a graph showing the noise absorption ratio P of sample 5 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 90 °, and the area ratio of the aluminum foil is 60%) (the cross angle θ s of the linear scratches is 90 °)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 14 is a graph showing the noise absorption ratio P of sample 6 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 90 °, and the area ratio of the aluminum foil is 80%) (the cross angle θ s of the linear scratches is 90 °, the area ratio of the aluminum foil is 80%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 15 is a graph showing the noise absorption ratio P of sample 7 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 90 °, and the area ratio of the aluminum foil is 100%) (the cross angle θ s of the linear scratches is 90 °)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 16 is a plan view showing samples 21 and 22(51 and 52) of the electromagnetic wave absorbing composite plate.

FIG. 17 is a graph showing noise absorption ratios P of samples 21 and 22 of the electromagnetic wave absorbing composite panel including aluminum foil sheets of different shapes_{Loss of power}/P_{Incident light}And the noise absorption ratio P of samples 1 and 4_{Loss of power}/P_{Incident light}The figure (a).

Fig. 18(a) is a graph showing electromagnetic wave noise at a frequency of about 3GHz leaking from the Fire Stick TV when the electromagnetic wave-absorbing composite panel of example 4 is placed on an IC chip in the Fire Stick TV.

Fig. 18(b) is a graph showing electromagnetic wave noise at a frequency of about 3GHz leaking from the Fire Stick TV without the electromagnetic wave absorbing composite panel.

FIG. 19 is a graph showing the noise absorption ratio P for samples 31-33 of electromagnetic wave absorbing composite panels comprising carbon sheets of graphite powder/carbon black_{Loss of power}/P_{Incident light}The figure (a).

Fig. 20 shows the noise absorption ratio P of sample 41 (intersection angle θ s of linear scratches is 60 °, and area ratio of aluminum foil is 20%) of the electromagnetic wave absorbing composite sheet_{Loss of power}/P_{Incident light}The figure (a).

Fig. 21 is a graph showing the noise absorption ratio P of the sample 42 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 60 °, and the area ratio of the aluminum foil is 30%) (the intersection angle θ s of the linear scratches is 60 °)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 22 shows a noise absorption ratio P of sample 43 (intersection angle θ s of linear scratches 60 °, and area ratio of aluminum foil 40%) of the electromagnetic wave absorbing composite sheet_{Loss of power}/P_{Incident light}The figure (a).

Fig. 23 is a graph showing the noise absorption ratio P of sample 44 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 60 °, and the area ratio of the aluminum foil is 50%) (the cross angle θ s of the linear scratches is 60 °)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 24 is a graph showing the noise absorption ratio P of sample 45 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 60 °, and the area ratio of the aluminum foil is 60%) (the cross angle θ s of the linear scratches is 60 °)_{Loss of power}/P_{Incident light}The figure (a).

FIG. 25 is a sample 46 showing an electromagnetic wave absorbing composite panel(intersection angle θ s of linear scratches is 60 °, and area ratio of aluminum foil is 70%) is the noise absorption ratio P_{Loss of power}/P_{Incident light}The figure (a).

Fig. 26 is a graph showing the noise absorption ratio P of sample 47 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 60 °, and the area ratio of the aluminum foil is 80%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 27 shows the noise absorption ratio P of sample 48 (intersection angle θ s of linear scratches 60 °, and area ratio of aluminum foil 100%) of the electromagnetic wave absorbing composite sheet_{Loss of power}/P_{Incident light}The figure (a).

Fig. 28 is a graph showing the noise absorption ratio P of sample 51 of the electromagnetic wave absorbing composite plate (the intersection angle θ s of the linear scratches is 60 °, and the distance D of the aluminum foil is 0mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 29 is a graph showing the noise absorption ratio P of the sample 52 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 60 °, and the distance D of the aluminum foil is 5mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 30 shows the noise absorption ratio P of sample 53 (the intersection angle θ s of the linear scratches is 60 °, and the distance D of the aluminum foil is 10mm) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 31 is a graph showing the noise absorption ratio P of sample 54 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 60 °, and the distance D of the aluminum foil is 15mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 32 shows the noise absorption ratio P of sample 55 (the intersection angle θ s of the linear scratches is 60 °, and the distance D of the aluminum foil is 20mm) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 33 is a graph showing the noise absorption ratio P of the sample 56 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 60 °, and the distance D of the aluminum foil is 25mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 34 shows the noise absorption ratio of sample 61 (intersection angle θ s of linear scratches is 30 °, and area ratio of aluminum foil is 20%) of the electromagnetic wave absorbing composite plateP_{Loss of power}/P_{Incident light}The figure (a).

Fig. 35 is a graph showing the noise absorption ratio P of the sample 62 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 30 °, and the area ratio of the aluminum foil is 30%) (the intersection angle θ s of the linear scratches is 30 °)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 36 shows the noise absorption ratio P of sample 63 (intersection angle θ s of linear scratches is 30 °, and area ratio of aluminum foil is 40%) of the electromagnetic wave absorbing composite sheet_{Loss of power}/P_{Incident light}The figure (a).

Fig. 37 is a graph showing the noise absorption ratio P of sample 64 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 30 °, and the area ratio of the aluminum foil is 50%) (the cross angle θ s of the linear scratches is 30 °, the area ratio of the aluminum foil is 50%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 38 is a graph showing the noise absorption ratio P of sample 65 (intersection angle θ s of linear scratches 30 °, and area ratio of aluminum foil 60%) of the electromagnetic wave absorbing composite sheet_{Loss of power}/P_{Incident light}The figure (a).

Fig. 39 is a graph showing the noise absorption ratio P of a sample 66 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 30 °, and the area ratio of the aluminum foil is 70%) (the intersection angle θ s of the linear scratches is 30 °, the area ratio of the aluminum foil is 70%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 40 is a graph showing the noise absorption ratio P of a sample 67 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 30 °, and the area ratio of the aluminum foil is 80%) (the cross angle θ s of the linear scratches is 30 °, the area ratio of the aluminum foil is 80%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 41 is a graph showing the noise absorption ratio P of a sample 68 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 30 °, and the area ratio of the aluminum foil is 100%) (the cross angle θ s of the linear scratches is 30 °, the area ratio of the aluminum foil is 100%) (the noise absorption ratio P is shown in the graph)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 42 shows a noise absorption ratio P of a sample 71 (intersection angle θ s of linear scratches is 30 °, and distance D of aluminum foil is 0mm) of an electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 43 shows a noise absorption ratio P of a sample 72 (intersection angle θ s of linear scratches is 30 °, and distance D of aluminum foil is 5mm) of an electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 44 shows the noise absorption ratio P of sample 73 (the intersection angle θ s of the linear scratches is 30 °, and the distance D of the aluminum foil is 10mm) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 45 is a graph showing the noise absorption ratio P of sample 74 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 30 °, and the distance D of the aluminum foil is 15mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 46 is a graph showing the noise absorption ratio P of sample 75 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 30 °, and the distance D of the aluminum foil is 20mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 47 shows the noise absorption ratio P of sample 76 (intersection angle θ s of linear scratches 30 °, and distance D of aluminum foil 25mm) of the electromagnetic wave absorbing composite sheet_{Loss of power}/P_{Incident light}The figure (a).

Fig. 48 shows the noise absorption ratio P of sample 81 (the intersection angle θ s of the linear scratches is 60 °, and the area ratio of the copper foil is 20%) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 49 shows the noise absorption ratio P of sample 82 (intersection angle θ s of linear scratches is 60 °, and area ratio of copper foil is 30%) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 50 shows the noise absorption ratio P of a sample 83 (the intersection angle θ s of the linear scratches is 60 °, and the area ratio of the copper foil is 40%) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 51 is a graph showing the noise absorption ratio P of sample 84 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 60 °, and the area ratio of the copper foil is 50%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 52 is a graph showing the noise absorption ratio P of sample 85 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 60 °, and the area ratio of the copper foil is 60%) (the intersection angle θ s of the linear scratches is 60 °)_{Loss of power}/P_{Incident light}The figure (a).

FIG. 53 is a graph showing a sample 86 of an electromagnetic wave absorbing composite plate (crossing angle of linear scratches)θ s 60 ° and the area ratio of the copper foil 70%), and noise absorption ratio P_{Loss of power}/P_{Incident light}The figure (a).

Fig. 54 is a graph showing the noise absorption ratio P of a sample 87 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 60 °, and the area ratio of the copper foil is 80%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 55 shows the noise absorption ratio P of sample 88 (intersection angle θ s of linear scratches is 60 °, and area ratio of copper foil is 100%) of the electromagnetic wave absorption composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 56 shows the noise absorption ratio P of a sample 91 (the intersection angle θ s of the linear scratches is 60 °, and the distance D of the copper foil is 0mm) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 57 shows the noise absorption ratio P of a sample 92 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 60 °, and the distance D of the copper foil is 5mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 58 is a graph showing the noise absorption ratio P of a sample 93 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 60 °, and the distance D of the copper foil is 10mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 59 is a graph showing the noise absorption ratio P of a sample 94 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 60 °, and the distance D of the copper foil is 15mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 60 shows a noise absorption ratio P of a sample 95 (intersection angle θ s of linear scratches is 60 °, and distance D of copper foil is 20mm) of an electromagnetic wave absorption composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 61 is a graph showing the noise absorption ratio P of a sample 96 of the electromagnetic wave absorbing composite plate (the intersection angle θ s of the linear scratches is 60 °, and the distance D of the copper foil is 25mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 62 is a graph showing the noise absorption ratio P of sample 101 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 45 °, and the area ratio of the copper foil is 20%) (the intersection angle θ s of the linear scratches is 45 °, the area ratio of the copper foil is 20%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 63 is a graph showing the noise absorption ratio P of sample 102 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 45 °, and the area ratio of the copper foil is 30%) (the cross angle θ s of the linear scratches is 45 °, the area ratio of the copper foil is 30%) (the noise absorption ratio P is shown in the graph_{Loss of power}/P_{Incident light}The figure (a).

Fig. 64 is a graph showing the noise absorption ratio P of sample 103 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 45 °, and the area ratio of the copper foil is 40%) (the intersection angle θ s of the linear scratches is 45 °, the area ratio of the copper foil is 40%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 65 shows the noise absorption ratio P of sample 104 (the intersection angle θ s of the linear scratches is 45 °, and the area ratio of the copper foil is 50%) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 66 shows the noise absorption ratio P of sample 105 (the intersection angle θ s of the linear scratches is 45 °, and the area ratio of the copper foil is 60%) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 67 is a graph showing the noise absorption ratio P of the sample 106 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 45 °, and the area ratio of the copper foil is 70%) (the intersection angle θ s of the linear scratches is 45 °, the area ratio of the copper foil is 70%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 68 is a graph showing the noise absorption ratio P of sample 107 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 45 °, and the area ratio of the copper foil is 80%) (the intersection angle θ s of the linear scratches is 45 °, the area ratio of the copper foil is 80%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 69 is a graph showing the noise absorption ratio P of the sample 108 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 45 °, and the area ratio of the copper foil is 100%) (the cross angle θ s of the linear scratches is 45 °, the area ratio of the copper foil is 100%) (the noise absorption ratio P is shown in the graph_{Loss of power}/P_{Incident light}The figure (a).

Fig. 70 is a graph showing the noise absorption ratio P of sample 111 of the electromagnetic wave absorbing composite plate (the intersection angle θ s of the linear scratches is 45 °, and the distance of the copper foil is 0mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 71 is a graph showing the noise absorption ratio P of sample 112 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 45 °, and the distance of the copper foil is 5mm)_{Loss of power}/P_{Incident light}The figure (a).

FIG. 72 is a drawingThe noise absorption ratio P of sample 113 (intersection angle θ s of linear scratches is 45 °, and distance of copper foil is 10mm) of the electromagnetic wave absorption composite plate is shown_{Loss of power}/P_{Incident light}The figure (a).

Fig. 73 is a graph showing the noise absorption ratio P of sample 114 of the electromagnetic wave absorbing composite plate (the intersection angle θ s of the linear scratches is 45 °, and the distance of the copper foil is 15mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 74 is a graph showing the noise absorption ratio P of the sample 115 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 45 °, and the distance of the copper foil is 20mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 75 is a graph showing the noise absorption ratio P of the sample 116 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 45 °, and the distance of the copper foil is 25mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 76 shows the noise absorption ratio P of sample 121 (intersection angle θ s of linear scratches is 30 °, and area ratio of copper foil is 20%) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 77 is a graph showing the noise absorption ratio P of sample 122 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 30 °, and the area ratio of the copper foil is 30%) (the intersection angle θ s of the linear scratches is 30 °)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 78 shows the noise absorption ratio P of sample 123 (intersection angle θ s of linear scratches is 30 °, and area ratio of copper foil is 40%) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 79 is a graph showing the noise absorption ratio P of sample 124 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 30 °, and the area ratio of the copper foil is 50%) (the intersection angle θ s of the linear scratches is 30 °, the area ratio of the copper foil is 50%) (the noise absorption ratio P is shown in the graph)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 80 is a graph showing the noise absorption ratio P of a sample 125 of the electromagnetic wave absorbing composite panel (the intersection angle θ s of the linear scratches is 30 °, and the area ratio of the copper foil is 60%)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 81 is a sample 126 showing an electromagnetic wave absorbing composite plate (intersection angle θ s of linear scratches 30)(ii) and the area ratio of the copper foil is 70%) as a noise absorption ratio P_{Loss of power}/P_{Incident light}The figure (a).

Fig. 82 shows the noise absorption ratio P of sample 127 (intersection angle θ s of linear scratches is 30 °, and area ratio of copper foil is 80%) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 83 is a graph showing the noise absorption ratio P of the sample 128 of the electromagnetic wave absorbing composite plate (the intersection angle θ s of the linear scratches is 30 °, and the area ratio of the copper foil is 100%) (the noise absorption ratio P is shown in the graph)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 84 is a graph showing the noise absorption ratio P of sample 131 of the electromagnetic wave absorbing composite sheet (the intersection angle θ s of the linear scratches is 30 °, and the distance of the copper foil is 0mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 85 is a graph showing the noise absorption ratio P of the sample 132 of the electromagnetic wave absorbing composite plate (the intersection angle θ s of the linear scratches is 30 °, and the distance of the copper foil is 5mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 86 is a graph showing the noise absorption ratio P of a sample 133 of the electromagnetic wave absorbing composite plate (the intersection angle θ s of the linear scratches is 30 °, and the distance of the copper foil is 10mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 87 is a graph showing the noise absorption ratio P of sample 134 (the intersection angle θ s of the linear scratches is 30 °, and the distance of the copper foil is 15mm) of the electromagnetic wave absorbing composite plate_{Loss of power}/P_{Incident light}The figure (a).

Fig. 88 is a graph showing the noise absorption ratio P of a sample 135 of the electromagnetic wave absorbing composite plate (the intersection angle θ s of the linear scratches is 30 °, and the distance of the copper foil is 20mm)_{Loss of power}/P_{Incident light}The figure (a).

Fig. 89 is a graph showing the noise absorption ratio P of a sample 136 of the electromagnetic wave absorption composite plate (the intersection angle θ s of the linear scratches is 30 °, and the distance of the copper foil is 25mm)_{Loss of power}/P_{Incident light}The figure (a).

Detailed Description

Embodiments of the present invention will be explained in detail with reference to the drawings, and it should be noted that the explanation of one embodiment is applicable to other embodiments unless otherwise specified. Also, the following explanation is not limiting, but various modifications may be made within the scope of the present invention.

Fig. 1(a) shows an electromagnetic wave absorption film 1 and an electromagnetic wave shielding film 2 laminated on the electromagnetic wave absorption film 1, which constitute an electromagnetic wave absorption composite panel 10 of the present invention, and fig. 1(b) shows an example of the electromagnetic wave absorption composite panel 10 of the present invention, which includes the electromagnetic wave absorption film 1 and the electromagnetic wave shielding film 2.

[1] Electromagnetic wave absorption film

As shown in fig. 2(a) and 2(b), the electromagnetic wave absorption film 1 includes a plastic film 11 and a single-layer or multi-layer metal thin film 12 formed on at least one surface of the plastic film 11, the metal thin film 12 having a large number of (a plurality of) substantially parallel discontinuous linear scratches having irregular widths and intervals in a plurality of directions.

(1) Plastic film

The resins forming the plastic film 11 are not particularly limited as long as they have sufficient strength, flexibility, and workability in addition to insulation, and they may be, for example, polyester (polyethylene terephthalate, etc.), polyarylsulfide (polyphenylene sulfide, etc.), polyamide, polyimide, polyamideimide, polyethersulfone, polyetheretherketone, polycarbonate, acrylic resin, polystyrene, polyolefin (polyethylene, polypropylene, etc.), and the like. From the viewpoint of strength and cost, polyethylene terephthalate (PET) is preferable. The thickness of the plastic film 11 is about 8 μm to 30 μm.

(2) Metallic film

The metal forming the metal thin film 12 is not particularly limited as long as it has conductivity, and they are preferably aluminum, copper, silver, tin, nickel, cobalt, chromium and alloys thereof, particularly aluminum, copper, nickel and alloys thereof, from the viewpoint of corrosion resistance and cost. The thickness of the metal thin film 12 is preferably 0.01 μm or more. Although not limited, the upper limit of the thickness of the metal thin film 12 may be about 10 μm in practice. Of course, the metal thin film 12 may be thicker than 10 μm without substantially changing the absorption capability of the high frequency electromagnetic wave. Therefore, the thickness of the metal thin film 12 is preferably 0.01 μm to 10 μm, more preferably 0.01 μm to 5 μm, and most preferably 0.01 μm to 1 μm. The metal thin film 12 can be prepared by a vapor deposition method (physical vapor deposition method such as vacuum vapor deposition method, sputtering method and ion plating method; or chemical vapor deposition method such as plasma CVD method, thermal CVD method and photo CVD method), an electroplating method or a foil bonding method.

When the metal thin film 12 has a single-layer structure, the metal thin film 12 is preferably made of aluminum or nickel from the viewpoints of conductivity, corrosion resistance, and cost. When the metal thin film 12 has a multilayer structure, one layer may be made of a non-magnetic metal, and the other layer may be made of a magnetic metal. The non-magnetic metal includes aluminum, copper, silver, tin and alloys thereof, and the magnetic metal includes nickel, cobalt, chromium and alloys thereof. The thickness of the magnetic metal thin film is preferably 0.01 μm or more, and the thickness of the non-magnetic metal thin film is preferably 0.1 μm or more. Although not limited, the upper limit of the thickness thereof may be about 10 μm in practice. More preferably, the thickness of the magnetic metal thin film is 0.01 μm to 5 μm, and the thickness of the non-magnetic metal thin film is 0.1 μm to 5 μm. Fig. 2(e) and 2(f) show two layers (metal films 12a, 12b) formed on the plastic film 11.

(3) Linear scratch

In the example shown in fig. 2(b) and 2 (c). The metal thin film 12 has a large number of substantially parallel discontinuous linear scratches 13(13a, 13b) having irregular widths and intervals in both directions. The depth of the linear scratches 13 is exaggerated in fig. 2(c) for illustrative purposes. As shown in fig. 2(d), the linear scratches 13 have various widths W and intervals I. The width W and the interval I of the linear scratches 13 are determined by the height corresponding to the surface S of the metal thin film 12 before the linear scratches are formed. Since the linear scratches 13 have various widths W and intervals I, the electro-magnetic wave absorption film 1 can effectively absorb electromagnetic noise in a wide frequency range.

The width W of 90% or more of the linear scratches 13 is preferably in the range of 0.1 μm to 100. mu.m, more preferably 0.5 μm to 50 μm, and most preferably 0.5 μm to 20 μm. The average width Wav of the linear scratches 13 is preferably 1 μm to 50 μm, more preferably 1 μm to 10 μm, and most preferably 1 μm to 5 μm.

The lateral spacing I of the linear scratches 13 preferably ranges from 1 μm to 500 μm, more preferably from 1 μm to 100 μm, most preferably from 1 μm to 50 μm, especially from 1 μm to 30 μm. The average lateral interval Iav of the linear scratches 13 is preferably 1 μm to 200. mu.m, more preferably 5 μm to 50 μm, and most preferably 5 μm to 30 μm.

Since the length Ls of the linear scratches 13 is determined by the slip conditions (mainly the relative circumferential speeds of the pattern roll and the laminating film, and the slip direction of the laminating film against the pattern roll), most of the linear scratches 13 have substantially the same length Ls (substantially equal to the average length Lsav) unless the slip conditions are changed. The length Ls of the linear scratches 13 is practically about 1mm to 100mm, preferably 2mm to 10mm, but is not particularly limited.

Unless otherwise specified, the acute intersection angle θ s of the linear scratches 13a, 13b may be simply referred to as "intersection angle θ s", which is preferably 30 to 90 °, more preferably 45 to 90 °. By adjusting the sliding conditions (relative circumferential speed, sliding direction, etc.) of the composite film against the pattern roll, linear scratches 13 having various intersection angles θ s can be obtained.

(4) Production method

Fig. 3(a) -3(e) show examples of an apparatus that forms the linear scratches 113(113a, 113b) in two directions. The apparatus includes (a) a reel 221 disposed in this order from upstream, unwinding a composite film 100 having a metal thin film 112 formed on a plastic film from the reel 221; (b) a first pattern roll 202a disposed in a direction different from the lateral direction of the composite film 100 on the side of the metal thin film 112; (c) a first pusher roll 203a disposed upstream of the first patterned roll 202a on the opposite side of the metal film 112; (d) a second pattern roll 202b disposed in the opposite direction to the first pattern roll 202a with respect to the transverse direction of the composite film 100 at the side of the metal film 112; (e) a second pushing roll 203b disposed downstream of the pattern roll 202b on the opposite side of the metal film 112; (f) a resistance measuring device 204a disposed on the side of the metal thin film 112 between the first patterned roll 202a and the second patterned roll 202 b; (g) a second resistance measuring device 204b provided downstream of the second pattern roll 202b on the metal thin film 112 side; and (h) a reel 224 around which the linear scratch composite film (electromagnetic wave absorption film) 111 is wound. Further, a plurality of guide rollers 222, 223 are provided at predetermined positions. Each patterned roll 202a, 202b is rotatably supported by a backing roll (e.g., a rubber roll) 205a, 205 b.

As shown in fig. 3(c), since the position of each of the pushing rolls 203a, 203b is lower than the position where the composite film 100 is in sliding contact with each of the pattern rolls 202a, 202b, the metal thin film 112 of the composite film 100 is pushed to each of the pattern rolls 202a, 202 b. When this condition is satisfied, the vertical position of each of the pushing rolls 203a, 203b can be adjusted to control the pressing force of each of the patterned rolls 202a, 202b against the metal thin film 112, and the center angle θ₁Proportional sliding distance.

Fig. 3(d) shows the principle of forming the linear scratches 113a on the composite film 100 to be inclined with respect to the moving direction of the composite film 100. Since the pattern roll 202a is inclined with respect to the moving direction of the composite film 100, the moving direction (rotational direction) a of the fine and hard particles on the pattern roll 202a is different from the moving direction b of the composite film 100. After the fine hard particles at point a on the pattern roll 202a come into contact with the metal thin film 112 to form a scratch B (as indicated by X), the fine hard particles move to point a 'and the scratch B moves to point B'. As the fine hard particles move from point a to point a ', the scratch is continuously formed, resulting in a linear scratch 113a extending from point B ' to point a '.

The direction and intersection angle θ s of the first and second linear scratches formed by the first and second patterned rolls 202a, 202b may be adjusted by varying the angle of each patterned roll 202a, 202b relative to the composite film 100 and/or the peripheral speed of each patterned roll 202a, 202b relative to the speed at which the composite film 100 is moving. For example, when the peripheral speed a of the pattern roll 202a is increased with respect to the moving speed b of the laminate film 100, the linear scratches 113a may be inclined, for example, at 45 ° with respect to the moving direction of the laminate film 100, as indicated by the line C 'D' shown by Y in fig. 3 (D). Similarly, the inclination θ of the patterned roll 202a relative to the transverse direction of the composite film 100 may be varied₂To change the peripheral speed a of the patterned roll 202 a. The same is true for patterned roll 202 b. Thus, by adjusting the patterned rolls 202a and 202b, the direction of the linear scratches 113a and 113b can be changed.

Because each patterned roll 202a, 202b is inclined relative to the compound film 100, sliding contact with each patterned roll 202a, 202b may be made in a transverse direction toward the compound film100 apply a force. Therefore, to prevent lateral movement of the composite film 100, the vertical position and/or angle of each of the pusher rolls 203a, 203b relative to each of the patterned rolls 202a, 202b is preferably adjusted. For example, the intersection angle θ between the axes of the patterned roll 202a and the pushing roll 203a is appropriately adjusted₃A pressing force having a lateral profile to eliminate a lateral component may be provided to prevent lateral movement. Adjusting the distance between the patterned roll 202a and the pusher roll 203a also helps prevent lateral movement. To prevent lateral movement and breakage of the composite film 100, the rotation direction of the first and second patterned rolls 202a and 202b inclined from the lateral direction of the composite film 100 is preferably the same as the moving direction of the composite film 100.

As shown in fig. 3(b), each resistance measuring device (roller) 204a, 204b includes a pair of electrodes (not shown) passing through insulating portions between which the resistance of the linearly scratched metal thin film 112 is measured. The resistances measured by the resistance measuring devices 204a, 204b are compared with target resistances to adjust the operating conditions such as the moving speed of the composite film 100, the rotating speed of the pattern rolls 202a, 202b, and the inclination angle θ according to their differences₂The position and the inclination angle theta of the pushing rollers 203a, 203b₃And the like.

To increase the pressing force of the patterned rolls 202a, 202b against the composite film 100, a third urging roll 203c may be provided between the patterned rolls 202a, 202b, as shown in FIG. 4. Third urging roller 203C and center angle θ₁The sliding distance of the metal thin film 12 is proportionally increased, resulting in longer linear scratches 113a, 113 b. Adjusting the position and the inclination angle of the third push roller 203c helps prevent lateral movement of the composite film 100.

Fig. 5 shows an example of an apparatus for forming linear scratches oriented in two perpendicular directions. This apparatus differs from the apparatus shown in fig. 3(a) -3(e) in that the second patterned roll 232b is parallel to the transverse direction of the composite film 100. Therefore, only portions different from those shown in fig. 3(a) -3(e) will be explained. The second patterned roll 232b may be rotated in the same direction or in the opposite direction as the composite film 100 is moved. Also, the second pusher roll 233b can be upstream or downstream of the second patterned roll 232 b. The apparatus aligns the direction of the linear scratches 113a ' (line E ' F ') with the transverse direction of the composite film 100, as indicated by Z in fig. 3(d), thereby forming 90 ° crossed linear scratches.

The operating conditions that determine not only the inclination angle and crossing angle of the linear scratches but also the depth, width, length and interval thereof are the moving speed of the composite film 100, the rotating speed and inclination angle of the pattern roll, the pressing force, and the like. The moving speed of the composite film 100 is preferably 5 to 200 m/min, and the peripheral speed of the pattern roll is preferably 10 to 2000 m/min. Inclination angle theta of pattern roll₂Preferably 20 to 60, especially about 45. The tension (parallel to the pressing force) of the composite film 100 is preferably 0.05 to 5kgf/cm wide.

The pattern roll used in the apparatus for forming linear scratches is preferably a roll having sharp edges and fine particles having a surface mohs hardness of 5 or more, for example, a diamond roll described in JP 2002-. Since the width of the linear scratches is determined by the size of the fine particles, the size of 90% or more of the fine diamond particles is preferably in the range of 1 μm to 1000 μm, more preferably in the range of 10 μm to 200 μm. The fine diamond particles are preferably adhered to the surface of the roll at an area ratio of 50% or more.

[2] Electromagnetic wave shielding film

In order to reflect the electromagnetic wave noise of the electromagnetic wave absorption film 1 and to project again onto the electromagnetic wave absorption film 1, the electromagnetic wave shielding film 2 should have a function of reflecting the electromagnetic wave noise. In order to effectively exhibit such a function, the electromagnetic wave-shielding film 2 is preferably a conductive metal foil; a plastic film having a conductive metal film or coating; or a carbon plate. The electromagnetic wave absorption film 1 and the electromagnetic wave shielding film 2 are preferably laminated by a non-conductive adhesive, which may be a known adhesive.

(1) Conductive metal foil

The conductive metal is preferably at least one selected from the group consisting of aluminum, copper, silver, tin, nickel, cobalt, chromium, and alloys thereof. The thickness of the conductive metal foil is preferably 5 μm to 50 μm.

(2) Thin films or coatings of electrically conductive metals

The conductive metal thin film is preferably a vapor-deposited film of the above-described conductive metal. The thickness of the vapor-deposited metal film may be tens of nanometers to tens of micrometers. The plastic film on which the vapor deposition film of the above-described conductive metal is formed may be the same as the plastic film 11 in the electromagnetic wave absorption film 1.

(3) Conductive metal coating

The conductive metal coating may be formed by: a plastic film is coated with an ink (paste) containing a conductive metal powder (such as silver powder or the like) highly dispersed in a thermoplastic resin or a photocurable resin, the resultant coating is dried, and then the coating is irradiated with ultraviolet rays as necessary. The conductive ink (paste) may be known, for example, a photo-curable conductive ink composition (JP 2016-; and the conductive filler has a particle size D₅₀And silver powder of 0.3 μm to 3.0 μm, wherein 50% by mass or more is in the form of a flake, foil or flake. The plastic film on which the conductive metal is coated may be the same as the plastic film 11 in the electromagnetic wave absorption film 1.

(4) Carbon plate

The carbon plate used as the electromagnetic wave shielding film may be a commercially available PGS (registered trademark) graphite plate (available from Panasonic Corporation) formed by heat-treating a polyimide film at an ultra-high temperature in an inert gas, the carbon plate (heat dissipation plate) including graphite powder, carbon black, and the like.

Carbon plates that can be used as graphite powder/carbon black are heat-dissipating plates having the following structure (JP 2015-: wherein the carbon black is uniformly dispersed among the fine graphite particles, the mass ratio of the fine graphite particles/the carbon black is 75/25-95/5, and the density is 1.9g/cm³Or higher, and an in-plane thermal conductivity of 570W/mK or higher. The fine graphite particles preferably have an average diameter of 5 μm to 100 μm and an average thickness of 200nm or more. The thickness of the heat dissipation plate is preferably 25 μm to 250 μm.

The heat dissipation plate may be formed by a method including: (1) preparing a dispersion containing, by mass, a total of 5 to 25% of fine graphite particles and carbon black, and 0.05 to 2.5% of a binder resin in an organic solvent, the mass ratio of the fine graphite particles to the carbon black being 75/25 to 95/5; (2) repeating the step of applying the dispersion to the surface of the support plate and the drying step a plurality of times to form a resin-containing composite sheet comprising fine graphite particles, carbon black, and a binder resin; (3) burning the resin-containing composite panel to remove the binder resin; and (4) pressing the resulting fine graphite particle/carbon black composite sheet to densify.

[3] Electromagnetic wave absorbing film and electromagnetic wave shielding film

(1) Area ratio

As shown in fig. 1(b), the area ratio of the electromagnetic wave-shielding film 2 to the electromagnetic wave-absorbing film 1 is 10 to 80%. When the area ratio is less than 10% or more than 80%, the absorption capability of the electromagnetic wave noise in the desired frequency range is not sufficiently maximized. This is an unexpected result, and an area ratio of the electromagnetic wave-shielding film 2 to the electromagnetic wave-absorbing film 1 of 10 to 80% is an important feature of the present invention. The lower limit of the area ratio is preferably 20%, more preferably 30%, further preferably 40%, most preferably 45%. The upper limit of the area ratio is preferably 70%, more preferably 65%, most preferably 60%. The area ratio of the electromagnetic wave shielding film 2 to the electromagnetic wave absorbing film 1 is, for example, preferably 20 to 80%, more preferably 30 to 70%, still more preferably 40 to 65%, most preferably 45 to 60%.

(2) Position of

The center of the electromagnetic wave-shielding film 2 is preferably located at the center of the electromagnetic wave-absorbing film 1, but may be deviated to change the frequency at which the electromagnetic wave-absorbing ability has a peak. The positional change of the electromagnetic wave shielding film 2 may be performed by moving the electromagnetic wave shielding film 2 in one direction with respect to the electromagnetic wave absorption film 1 as shown in fig. 6(a), or by reducing the size of the electromagnetic wave shielding film 2 so that the four sides of the electromagnetic wave shielding film 2 are retracted inward from the four sides of the electromagnetic wave absorption film 1 as shown in fig. 6 (b). In both cases, since how the electromagnetic wave-shielding film 2 is moved or changed in size with respect to the electromagnetic wave-absorbing film 1 affects the frequency at which the electromagnetic wave-absorbing ability has a peak, it is preferably determined according to the frequency range in which the electromagnetic wave-absorbing ability is maximized. Of course, in either of the embodiments 6(a) and 6(b), the area ratio of the electromagnetic wave-shielding film 2 to the electromagnetic wave-absorbing film 1 should satisfy the above requirements.

The present invention will be explained in more detail with reference to the following examples, without intending to limit the present invention thereto.

Reference example 1

Linear scratches oriented in two directions at a crossing angle θ s of 90 ° were formed in an aluminum thin film having a thickness of 0.05 μm formed on the surface of a biaxially oriented polyethylene terephthalate (PET) film having a thickness of 16 μm by a vacuum vapor deposition method using an apparatus having a structure as shown in fig. 5, which includes pattern rolls 232a, 232b having electroplated fine diamond particles with a particle size distribution of 50 μm to 80 μm. Optical micrographs of linearly scratched aluminum films show that linear scratches have the following characteristics:

range of width W: 0.5-5 μm in diameter,

average width Wav: the thickness of the film is 2 mu m,

range of interval I: 2-30 μm of the total particle size,

average interval Iav: the thickness of the film is 20 mu m,

average length Lsav: 5mm, and

intersection angle θ s: at 90 deg..

Reference example 2

An apparatus having a structure shown in fig. 3, which includes pattern rolls 202a, 202b having electroplated fine diamond particles with a particle size distribution of 50 μm to 80 μm, was used to form linear scratches oriented in two directions at a crossing angle θ s of 60 ° in an aluminum thin film having a thickness of 0.05 μm, which was formed on the surface of a PET film having a thickness of 16 μm by a vacuum vapor deposition method. Optical micrographs of linearly scratched aluminum films show that linear scratches have the following characteristics:

range of width W: 0.5-5 μm in diameter,

average width Wav: the thickness of the film is 2 mu m,

range of interval I: 2-30 μm of the total particle size,

average interval Iav: the thickness of the film is 20 mu m,

average length Lsav: 5mm, and

intersection angle θ s: 60 degrees.

Reference example 3

An aluminum thin film having a thickness of 0.05 μm formed on the surface of a PET film having a thickness of 16 μm by a vacuum vapor deposition method was provided with linear scratches oriented in two directions at a crossing angle θ s of 45 ° by the same method as in reference example 2, except that the crossing angle θ s was changed to 45 °, thereby preparing an electromagnetic wave absorption film.

Reference example 4

An aluminum thin film having a thickness of 0.05 μm formed on the surface of a PET film having a thickness of 16 μm by a vacuum vapor deposition method was provided with linear scratches oriented in two directions at a crossing angle θ s of 30 ° by the same method as in reference example 2, except that the crossing angle θ s was changed to 30 °, thereby preparing an electromagnetic wave absorption film.