JP2004303914A - Electromagnetic wave shielding sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent electromagnetic wave shielding sheet which may be manufactured easily and also easily realizes electrical continuity even when it is adhered to objects of various sizes. <P>SOLUTION: The electromagnetic wave shielding sheet is formed by sequentially laminating a transparent base material layer 2, a conductive material layer 4 having a plurality of apertures 5, and a transparent adhesive material layer 7 having conductivity. In this sheet, the adhesive material layer 7 is in contact with at least a part of the conductive material layer 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electromagnetic wave shielding sheet having transparency, and is attached to a surface of a display device such as a PDP to shield electromagnetic waves generated from the display device, or is attached to a window to shield external electromagnetic waves. It is suitably used as an electromagnetic wave shielding sheet for performing the above.
[0002]
[Prior art]
Electromagnetic waves generated from an electric device such as a display device may cause other electric devices to malfunction, and there is a concern that the electromagnetic wave may affect a human body. Therefore, it is desired to shield electromagnetic waves generated from these electric devices. Further, in an indoor space where precision equipment is used, it is desired to shield electromagnetic waves from outside in order to prevent malfunction of the precision equipment. In response to the former request, for example, an electromagnetic wave shielding sheet is attached to the front of the display device to shield the electromagnetic waves generated from the display device. A sheet is attached to shield electromagnetic waves coming from outside.
[0003]
In the case of an electromagnetic wave shielding sheet attached to a display device or a window glass as described above, it is naturally required to have an electromagnetic wave shielding property. In addition, the electromagnetic wave shielding sheet when observed from the front side of the electromagnetic wave shielding sheet is used. (Transparency) is required to be able to observe images, scenes, and the like on the back side of the camera. As an electromagnetic wave shielding sheet having such transparency, for example, an electromagnetic wave shielding sheet formed by providing a conductive layer having an opening on a base material layer is known.
[0004]
By the way, when an electromagnetic wave is shielded by an electromagnetic wave shielding sheet, a part of the electromagnetic wave is absorbed by the conductive layer of the electromagnetic wave shielding sheet, and therefore, the conductive layer is formed by establishing electrical continuity between the conductive layer and an edge of a display device or a window glass. Need to release the electricity stored in the As an electromagnetic wave shielding sheet capable of establishing electrical continuity between the conductive layer and the edge of the display device or the window glass, for example, a transparent adhesive layer laminated on the conductive layer at the periphery of the conductive layer There is an electromagnetic wave shielding sheet for a PDP in which electrodes are formed so as to extend to the front side along the side surface of PDP (for example, see Patent Document 1). By attaching this electromagnetic wave shielding sheet to a PDP using a transparent adhesive layer, it is possible to establish electrical conduction between the conductive layer and the PDP via an electrode.
[Patent Document 1]
JP-A-2002-6106
[Problems to be solved by the invention]
However, in the electromagnetic wave shielding sheet of Patent Document 1, 1) there is a problem that a process of forming an electrode is complicated and manufacturing cost is increased, and 2) an electrode is formed on a peripheral portion of the electromagnetic wave shielding sheet so that it is attached. Unless the size of the object is determined, electrodes cannot be formed, and conversely, it becomes an electromagnetic wave shielding sheet dedicated to the size of the target part to be pasted and can not be diverted to other sizes was there.
[0006]
The present invention has been made in view of such a problem, and has as its main object the main object of the present invention is that it is easy to manufacture, and that it can be easily electrically connected to various sizes of objects to be attached. It is an object of the present invention to provide a transparent electromagnetic wave shielding sheet that can conduct electricity.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the electromagnetic wave shielding sheet of the present invention is an electromagnetic wave formed by laminating a transparent base material layer, a conductive material layer having a plurality of openings, and a transparent adhesive material layer in this order. In the shielding sheet, the pressure-sensitive adhesive layer is in contact with at least a part of the conductive material layer, and the pressure-sensitive adhesive layer is configured to have conductivity (claim 1).
[0008]
According to this electromagnetic wave shielding sheet, it can be easily manufactured by sequentially laminating the base material layer, the conductive material layer and the adhesive layer, and the electromagnetic wave shielding sheet is cut according to the size of the object to be stuck. Then, electrical continuity can be easily obtained by sticking to an object using the adhesive layer. Further, transparency can be ensured by the plurality of openings of the conductive material layer.
[0009]
In this electromagnetic wave shielding sheet, it is preferable to form an adhesive layer containing an inorganic conductive filler (Claim 2), and to form an adhesive layer with a conductive polymer (Claim 3).
[0010]
Further, in this electromagnetic wave shielding sheet, it is preferable that the surface resistivity of the adhesive layer be 10 ⁷ Ω / □ or less.
[0011]
By forming the surface resistivity of the pressure-sensitive adhesive layer in this range, electrical conduction between the conductive material layer and the object to be pasted or the edge thereof can be ensured. That is, when the surface resistivity exceeds 10 ⁷ Ω / □, electric conduction is not sufficient, and in order to ensure electric conduction between the electric material layer and the object to be stuck or its edge, the surface resistivity must be increased. More preferably, it is set to 10 ⁴ Ω / □ or less. Further, the surface resistivity of the pressure-sensitive adhesive layer is preferably 10 ⁻² Ω / □ or more.
[0012]
Further, in these electromagnetic wave shielding sheets, the conductive material layer is preferably laminated on the base material layer via an adhesive layer.
[0013]
According to this, the base material layer and the conductive material layer can be easily bonded.
[0014]
Further, in these electromagnetic wave shielding sheets, it is preferable that a colored resin layer is provided between the conductive material layer except for the opening and the adhesive material layer.
[0015]
According to this, the design property when the electromagnetic wave shielding sheet is viewed from the front side can be improved, and further, by forming the resin layer in a dark color such as black, external light is absorbed and the transparency is improved. be able to.
[0016]
In these electromagnetic wave shielding sheets, the openings may be formed so that the aperture ratio of the conductive material layer is 60 to 90% (claim 7).
[0017]
According to this, the electromagnetic wave can be reliably shielded, and the transparency of the electromagnetic wave shielding sheet can be sufficiently ensured. That is, if the aperture ratio exceeds 90%, it is difficult to reliably shield electromagnetic waves, and if it is less than 60%, sufficient transparency cannot be obtained. It is more preferable that the aperture ratio be 80% or less in order to more reliably shield the electromagnetic waves, and the aperture ratio be 70% or more in order to allow the observer to see through without discomfort. More desirable.
[0018]
Further, in this electromagnetic wave shielding sheet, it is preferable that a plurality of openings are formed regularly over the entire area of the conductive material layer.
[0019]
According to this, the transparency of the electromagnetic wave shielding sheet can be made uniform over the entire surface, and the observer does not feel uncomfortable about the observation.
[0020]
Further, in the electromagnetic wave shielding sheet, the opening is preferably formed in a band shape, a polygonal shape, or a circular shape.
[0021]
According to this, the openings are formed in an orderly shape, so that the observer does not feel uncomfortable.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0023]
1. 1st Embodiment 1) Electromagnetic wave shielding sheet FIG. 1 is a perspective view showing a basic configuration of an electromagnetic wave shielding sheet according to a first embodiment of the present invention, and FIG. 2 is a basic view of the electromagnetic wave shielding sheet of FIG. It is sectional drawing which showed the structure typically. For convenience of drawing, FIG. 1 illustrates the electromagnetic wave shielding sheet with the back side facing upward, and FIG. 2 illustrates the electromagnetic wave shielding sheet with the front side facing upward.
[0024]
As shown in FIGS. 1 and 2, the electromagnetic wave shielding sheet 1 according to the first embodiment includes a sheet-shaped base layer 2 and a conductive material layer formed on the surface of the base layer 2 with an adhesive layer 3 interposed therebetween. 4, a resin layer 6 formed on the surface of the conductive material layer 4, and an adhesive layer 7 further formed on the surface.
[0025]
The base material layer 2 is a base material formed in a sheet shape from a substantially transparent material, and is made of a resin material such as a polyester resin, an acrylic resin, a polycarbonate resin, a styrene resin, a polyolefin resin, or an inorganic material such as glass. It can be formed of a material. The thickness of the base material layer 2 is not particularly limited, but is usually about 0.05 to 0.5 mm.
[0026]
The adhesive layer 3 is a layer for bonding the conductive material layer 4 to the base material layer 2 and is formed of a substantially transparent adhesive. For example, it is formed using a substantially transparent adhesive such as polyurethane, epoxy, or acrylic.
[0027]
The conductive material layer 4 is formed of a conductive material (conductive material). The conductive material layer 4 plays a role of mainly shielding electromagnetic waves in the electromagnetic wave shielding sheet 1. That is, the conductive material layer 4 reflects the passing electromagnetic wave on the surface of the conductive material layer 4 and absorbs and attenuates the electromagnetic wave inside the conductive material layer 4. The material of the conductive material layer 4 may be any conductive material, but is particularly preferably a conductive material having a surface resistivity of 1 Ω / □ or less, for example, silver, copper, gold, aluminum or the like. . By using a conductive material having a high surface resistivity as described above, the electromagnetic wave shielding sheet 1 can sufficiently shield electromagnetic waves. The thickness of the conductive material layer 4 is not particularly limited, but is usually about 0.005 to 0.05 mm.
[0028]
The conductive material layer 4 has a plurality of openings 5. The openings 5 are regularly arranged over the entire area of the conductive material layer 4 and formed to penetrate the conductive material 4. Due to the presence of the openings 5, the electromagnetic wave shielding sheet 1 has transparency. The opening 5 is formed such that the opening ratio of the conductive material layer 4 is 60 to 90%, preferably 70 to 80%. The shape of the opening 5 is, for example, rectangular as shown in FIG.
[0029]
The resin layer 6 is made of a resin and is formed in a portion other than the opening 5 of the conductive material layer 4. For example, a polyester resin, an epoxy resin, a urethane resin, or the like can be used as a resin constituting the resin layer 6, and a colored resin obtained by adding carbon black or the like to these resins can also be used. When the resin layer 6 is formed using a colored resin, the colored resin layer 6 is observed when the electromagnetic wave shielding sheet 1 is observed from the surface, so that the design can be improved, and furthermore, the black color or the like can be improved. In the case where the resin layer 6 is formed using the dark resin described above, external light can be absorbed to improve the transparency. Further, the resin layer 6 is used as a masking material for preventing the conductive material layer 4 in a portion other than the opening 5 from being dissolved when the conductive material layer 4 is etched and dissolved in a method of manufacturing the electromagnetic wave shielding sheet 1 described below. Plays a role. The thickness of the resin layer 6 is not particularly limited, but is usually about 0.001 to 0.01 mm.
[0030]
The pressure-sensitive adhesive layer 7 is formed of a transparent conductive pressure-sensitive adhesive, and is formed of, for example, a conductive polymer type adhesive or an inorganic type conductive filler-added type adhesive.
[0031]
Examples of the conductive polymer type adhesive include poly (oxyethylene) alkylamine, poly (oxyethylene) alkylamide, poly (oxyethylene) alkyl ether, poly (oxyethylene) alkylphenyl ether, glycerin fatty acid ester, and anionic type. Alkyl sulphonate, alkyl benzene sulphonate, alkyl sulphate, alkyl phosphate, quaternary ammonium chloride, quaternary ammonium sulphate, quaternary ammonium night sheet, alkyl petaine type resin, alkyl imidazoline type resin, alkyl alanine type resin in the cationic system, There is an adhesive made of a polyvinyl benzyl type cation resin, a polyacrylic acid type cation resin or the like.
[0032]
Examples of the conductive filler-added adhesive include a zinc oxide-based filler such as ZnO (Al), a barium sulfate-based filler such as SnO ₂ (Sb) / BaSO ₄ , and a barium sulfate such as SnO ₂ / BaSO _4. system (undoped) _{filler, SnO 2 (Sb) / 9Al} 2 O 3 · 2B 2 aluminum borate systems, such as _{O 3} (needle) _filler, SnO 2 (Sb) / titanium oxide-based filler, such as TiO _2, SnO ₂ tin oxide such as (Sb) (ultrafine) filler, TiO titanium black filler such as _{(N), SnO 2 (Sb} ) / K 2 O · nTiO 2 and _C / K ₂ O · nTiO 2 Inorganic conductive fillers such as potassium titanate (needle) fillers are added to a known adhesive. Here, the substance on the left side of / indicates the coating material, and the substance on the right side of / indicates the core material. The substance in parentheses is a doping agent, for example, ZnO (Al) is a substance obtained by adding a small amount of aluminum to zinc oxide. SnO ₂ (Sb) / BaSO ₄ is a substance obtained by coating a core agent of barium sulfate with tin oxide to which a small amount of antimony is added.
[0033]
The pressure-sensitive adhesive layer 7 is formed such that the respective components are adjusted so that the surface resistivity is 10 ⁷ Ω / □ or less, more preferably 10 ⁴ Ω / □ or less. The adhesive layer 7 is formed so that the haze value is 10% or less, more preferably 5% or less, in order to secure the transparency of the electromagnetic wave shielding sheet 1. The thickness of the adhesive layer 7 is not particularly limited, but is usually 0.01 mm or more.
[0034]
2) Method of manufacturing electromagnetic wave shielding sheet Next, an example of a method of manufacturing the electromagnetic wave shielding sheet 1 will be described with reference to FIG. Here, a method of manufacturing the electromagnetic wave shielding sheet 1 using a metal material as a conductive material forming the conductive material layer 4 and using an ultraviolet curable ink containing carbon particles as a resin forming the resin layer 6 will be described. FIG. 2 is a cross-sectional view schematically showing a state of the electromagnetic wave shielding sheet 1 at each manufacturing stage.
[0035]
First, a metal foil is adhered to the surface of the base material layer 2 via an adhesive 3 to form a conductive material layer 4 (FIG. 3A). Next, a resin layer 6 having a pattern opposite to the shape of the opening 5 is formed on the surface of the conductive material layer 4 using an ultraviolet curable ink containing carbon particles (FIG. 3B). Next, an opening 5 is formed by removing the portion of the conductive material layer 4 not covered with the resin layer 6 by etching (FIG. 3C). Next, a conductive adhesive is applied to the surface of the resin layer 6 including the openings 5 by a printing method to form an adhesive layer 7 (FIG. 3D). For convenience in handling the electromagnetic wave shielding sheet 1, a release sheet may be attached to the surface of the adhesive layer 7 as necessary.
[0036]
3) Function of electromagnetic wave shielding sheet The electromagnetic wave shielding sheet 1 configured as described above is attached to, for example, a PDP. In this case, the electromagnetic wave shielding sheet 1 is attached to the PDP by bonding the adhesive layer 7 to the surface of the PDP.
[0037]
The electromagnetic wave shielding sheet 1 affixed to the PDP reflects electromagnetic waves generated by the PDP on the surface of the conductive material layer 4 and absorbs and attenuates the electromagnetic waves inside the conductive material layer 4. Therefore, the electromagnetic wave shielding sheet 1 greatly reduces the amount of electromagnetic waves emitted from the PDP to the outside.
[0038]
Further, as described above, since the adhesive layer 7 has conductivity, the conductive layer 4 is electrically connected to the PDP and the periphery thereof via the adhesive layer 7, and therefore, the conductive layer 4 The absorbed electricity is released to the PDP and its periphery.
[0039]
Furthermore, the base material layer 2, the adhesive layer 3, and the adhesive layer 7 are formed transparent, and the conductive material layer 4 has a plurality of openings 5, so that the image of the PDP can be displayed through the electromagnetic wave shielding sheet 1. Even when observing, an image can be easily observed.
[0040]
2. Other Embodiments In the first embodiment, the case where the conductive material layer 4 is formed on the surface of the transparent substrate 2 via the adhesive layer 3 has been described. However, the present invention is not limited to this. Alternatively, the conductive material layer 4 may be formed directly on the surface of the substrate 2. In this case, for example, the conductive material layer 4 may be formed on the surface of the transparent substrate 2 by vapor deposition, thermal spraying, plating, or the like.
[0041]
Further, in the first embodiment, the case where the opening 5 is formed in a rectangular shape is shown. However, the present invention is not limited to this. For example, as shown in FIG. 4, a band, a circle, another polygon (a triangle, Hexagon).
[0042]
Furthermore, in the first embodiment, the case in which the resin layer 6 is formed on the surface of the conductive material layer 4 has been described. However, the present invention is not limited to this, and the electromagnetic wave shielding sheet 1 may be formed without the resin layer 6. Is also good.
[0043]
Furthermore, the present invention is not limited to the embodiments described above, and various modifications and changes can be made within the scope of the invention described in the claims.
[0044]
【Example】
Rolled copper (3 to 5 μm) as a conductive material layer is applied to a polyethylene terephthalate film (100 U-94, 100 thickness, manufactured by Toray) as an easily contacted base material layer and an adhesive (hardening agent C55 to E295L manufactured by Dainichi Seika) After bonding using a UV curable ink (Intec's epoxy acrylate-based carbon-containing ink, UFL black, PV ratio: about 25%), a lattice pattern is formed by flexographic printing. (Line width 30 μm, space 250 μm) was printed.
[0045]
Next, this was immersed in an aqueous ferric chloride solution at 50 ° C. for about 30 seconds to dissolve and remove the rolled copper in the portion where the UV curable ink was not printed. Then, an adhesive (AG-9014A manufactured by Asahi Glass) containing 5% of barium sulfate coated with antimony-doped tin oxide was applied thereto at a rate of 5 to 6 g / m2 (dry weight) by a gravure printing method. An adhesive layer was formed.
[0046]
The electromagnetic wave shielding sheet thus formed exhibited high transparency, with an aperture ratio of rolled copper of 80%, and high electromagnetic wave shielding performance of 40 to 50 dB in a frequency range of 1 GHz or less and 1 to 5 GHz, respectively. . Furthermore, the electrical conduction with the PDP was also good.
[0047]
【The invention's effect】
As described above, according to the electromagnetic wave shielding sheet of the present invention, it can be easily manufactured by sequentially laminating the base material layer, the conductive material layer, and the adhesive layer. By cutting according to the size of the object and sticking it to the object using the adhesive layer, electrical conduction can be easily obtained. Furthermore, transparency can be ensured by a plurality of openings of the conductive material layer (claim 1). The pressure-sensitive adhesive layer can be formed by containing an inorganic conductive filler (Claim 2), or can be formed by a conductive polymer (Claim 3).
[0048]
Further, by setting the surface resistivity of the adhesive layer to 10 ⁷ Ω / □ or less, electrical conduction between the conductive layer and the object to be pasted or the edge thereof can be ensured (claim 4).
[0049]
Further, by laminating the conductive material layer on the base material layer via the adhesive layer, the base material layer and the conductive material layer can be easily bonded.
[0050]
In addition, by having a colored resin layer between the conductive material layer and the adhesive material layer except for the opening, it is possible to improve the design when the electromagnetic wave shielding sheet is viewed from the front side, and furthermore, the resin layer Is formed in a dark color such as black so that external light can be absorbed and the transparency can be improved (claim 6).
[0051]
Further, by forming the openings so that the aperture ratio of the conductive material layer is 60 to 90%, it is possible to reliably shield the electromagnetic waves and sufficiently secure the transparency of the electromagnetic wave shielding sheet. 7).
[0052]
Furthermore, by forming the plurality of openings regularly over the entire area of the conductive material layer, the transparency of the electromagnetic wave shielding sheet can be made uniform over the entire surface, so that the observer does not feel uncomfortable. (Claim 8).
[0053]
Further, by forming the opening portion in a band shape, a polygonal shape, or a circular shape, it is possible to further prevent the observer from feeling uncomfortable (claim 9).
[Brief description of the drawings]
FIG. 1 is a perspective view showing a basic configuration of an electromagnetic wave shielding sheet according to a first embodiment.
FIG. 2 is a cross-sectional view schematically illustrating a basic configuration of the electromagnetic wave shielding sheet according to the first embodiment.
FIG. 3 is a cross-sectional view schematically showing a state at each manufacturing stage of the electromagnetic wave shielding sheet according to the first embodiment.
FIG. 4 is a diagram showing a shape of an opening of an electromagnetic wave shielding sheet according to another embodiment.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 electromagnetic wave shielding sheet 2 substrate layer 3 adhesive layer 4 conductive material layer 5 opening 6 resin layer 7 adhesive layer

Claims (9)

A transparent base material layer, a conductive material layer having a plurality of openings, and a transparent adhesive material layer, in an electromagnetic wave shielding sheet formed by laminating in this order,
The electromagnetic wave shielding sheet, wherein the pressure-sensitive adhesive layer is in contact with at least a part of the conductive material layer, and the pressure-sensitive adhesive layer has conductivity. The electromagnetic wave shielding sheet according to claim 1,
An electromagnetic wave shielding sheet, wherein the adhesive layer contains an inorganic conductive filler. The electromagnetic wave shielding sheet according to claim 1,
The electromagnetic wave shielding sheet, wherein the adhesive layer is made of a conductive polymer. The electromagnetic wave shielding sheet according to any one of claims 1 to 3,
An electromagnetic wave shielding sheet, wherein the pressure-sensitive adhesive layer has a surface resistivity of 10 ⁷ Ω / □ or less. The electromagnetic wave shielding sheet according to any one of claims 1 to 4,
The electromagnetic wave shielding sheet, wherein the conductive material layer is laminated on the base material layer via an adhesive layer. The electromagnetic wave shielding sheet according to any one of claims 1 to 5,
An electromagnetic wave shielding sheet having a colored resin layer between the conductive material layer except the opening and the adhesive material layer. The electromagnetic wave shielding sheet according to any one of claims 1 to 6,
The electromagnetic wave shielding sheet, wherein the openings are formed such that the opening ratio of the conductive material layer is 60 to 90%. The electromagnetic wave shielding sheet according to claim 7,
The electromagnetic wave shielding sheet, wherein the plurality of openings are regularly formed over the entire area of the conductive material layer. The electromagnetic wave shielding sheet according to claim 8,
An electromagnetic wave shielding sheet, wherein the opening is formed in a band, polygon, or circle.

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