JP2002341778A - Light transmitting window material with shielding property against electromagnetic wave - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light transmitting window material having shielding property against electromagnetic waves which is excellent in the shielding property against electromagnetic waves and has high antireflection effect and excellent transparency and visibility so that sharp images can be obtained. SOLUTION: The light transmitting window material 1 having shielding property against electromagnetic waves is obtained by laminating and integrating an antireflection film 3, a film 10 having shielding property against electromagnetic waves, a transparent substrate 2, and a near IR cut film 5 with intermediate films 4A, 4B for adhesion and with a pressure sensitive adhesive 4C, and then covering the peripheral edge part with a conductive cohesive tape 7. Conductive cohesive tapes 7, 8 are stuck to the peripheral edge of the film 10 having shielding property against electromagnetic waves and to the peripheral edge of the laminated body. The film 10 is produced by adhering the following conductive foil 11 to a transparent base film 13 with a transparent adhesive 14 and then by pattern etching. The conductive foil 11 is prepared by forming a light absorbing layer 12 on its surface and subjecting the surface of the absorbing layer 12 to roughening treatment for antireflection and non-gloss treatment. The rugged pattern on the surface of the transparent adhesive 14 is filled with a crosslinking thermosetting resin of the intermediate film 4B for adhesion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shielding light transmitting window material, and more particularly to an electromagnetic wave shielding property, transparency, and the like.
Excellent visibility, PDP (plasma display panel)
The present invention relates to an electromagnetic wave shielding light transmitting window material useful as a front filter or the like of the invention.

[0002]

2. Description of the Related Art In order to shield an electromagnetic wave generated from a display of an OA device, a communication device or the like, a window material having an electromagnetic wave shielding property and a light transmitting property is sometimes attached to the front of the OA device. . Such a window material is also used as a window material in a place where precision equipment is installed, such as a hospital or a laboratory, in order to protect precision equipment from electromagnetic waves such as mobile phones.

[0003] A conventional electromagnetic-shielding light-transmitting window material has a structure in which a conductive mesh material such as a wire mesh or a transparent conductive film is interposed between transparent substrates such as an acrylic plate.

The conductive mesh used for the conventional electromagnetic wave shielding light transmitting window material has a wire diameter of about 10 to 500 μm and a mesh of about 5 to 500 mesh, and an aperture ratio of 75%.
Is less than. In a conventional electromagnetic wave shielding light transmitting window material using such a conductive mesh, the light transmittance is at most 70.
% And low.

[0005] In a display provided with a conventional electromagnetic shielding light transmitting window provided with a conductive mesh, moire (interference fringes) is likely to occur due to the pixel pitch of the display.

In order to solve such a problem, it has been proposed to use a conductive foil subjected to pattern etching as an electromagnetic wave shielding layer instead of a conductive mesh (Japanese Patent Laid-Open No. 2000-174491). An electromagnetic wave shielding light transmitting window material having a conductive foil pattern-etched to have a desired wire diameter, spacing, and mesh shape has good electromagnetic wave shielding properties and light transmitting properties, and has no moire phenomenon.

In the pattern etching of the conductive foil, a metal foil is adhered to the surface of a transparent substrate film, and a photoresist film is pressed on the metal foil, and a predetermined pattern is formed by a pattern exposure and etching process. This is done by etching, so that the metal foil is provided as a film laminated to the substrate film.

[0008]

In such an electromagnetic wave shielding film composed of a laminated film of a metal foil / base film, light is reflected on the surface of the metal foil and sufficient visibility cannot be obtained.

An object of the present invention is to solve the above-mentioned conventional problems and to provide an electromagnetic wave shielding light transmitting window material which is excellent in electromagnetic wave shielding properties, has a high antireflection effect, and is excellent in transparency and visibility. I do.

[0010]

According to a first aspect of the present invention, there is provided an electromagnetic wave shielding light transmitting window material comprising at least an electromagnetic wave shielding film and a transparent substrate laminated and integrated. The film is provided with a transparent base film, a conductive foil which is adhered to a surface of the base film on the side of the transparent substrate by a transparent adhesive, and is pattern-etched, and the base film side of the foil. A light-absorbing layer for preventing reflection is provided on the surface, and the surface of the light-absorbing layer on the substrate film side is subjected to a roughening treatment.

In the electromagnetic wave shielding film used in the present invention, fine irregularities are formed on the surface of the light absorbing layer by surface roughening treatment (hereinafter, this surface roughening treatment is referred to as "matte treatment").
It may be called. Therefore, the antireflection effect is high. Therefore, when the electromagnetic wave shielding light transmitting window material having this electromagnetic wave shielding film is attached to the front of the display,
A clear image with high contrast can be obtained.

The electromagnetic wave shielding film composed of the pattern-etched foil, the matte light-absorbing layer, and the substrate film is manufactured, for example, by the following procedure. A light absorbing layer is formed on the surface of the metal foil, and the surface of the light absorbing layer is subjected to a roughening treatment. Is bonded to a transparent base film with a transparent adhesive. Is subjected to pattern etching.

In the above-mentioned bonding step, the unevenness on the surface of the light-absorbing layer subjected to the matte treatment is transferred to the transparent adhesive layer. For this reason, the surface of the transparent adhesive layer exposed after the light absorbing layer and the metal foil are removed by the pattern etching is an uneven surface transferred from the light absorbing layer.

The uneven surface of such a transparent adhesive layer has the property of scattering light. Then, in the present invention, claim 2
As described above, the foil side surface of the electromagnetic wave shielding film is bonded to the transparent substrate with a thermosetting resin, and the unevenness transferred to the transparent adhesive layer is filled with the thermosetting resin to prevent scattering of light. It is desirable to increase the transparency.

According to a third aspect of the present invention, there is provided an electromagnetic wave shielding light transmitting window material according to the second aspect, wherein the thermosetting resin is a crosslinked thermosetting resin containing a crosslinking agent.

By using a cross-linking type thermosetting resin containing a cross-linking agent as the thermosetting resin, in producing an electromagnetic wave shielding light transmitting window material, after being temporarily press-bonded with the thermosetting resin, heating is performed while applying pressure. By doing so, the electromagnetic wave shielding film and the transparent substrate can be firmly bonded and integrated without leaving bubbles at the bonding interface.

According to a fourth aspect of the present invention, there is provided the electromagnetic wave shielding light transmitting window material according to the second or third aspect, wherein the cured thermosetting resin and the transparent adhesive of the electromagnetic wave shielding film have substantially the same refractive index. Features.

By making the refractive indices of the cured thermosetting resin and the transparent adhesive of the electromagnetic wave shielding film substantially equal to each other, light scattering at the interface between the thermosetting resin and the transparent adhesive layer can be further ensured. Can be prevented.

According to a fifth aspect of the present invention, there is provided an electromagnetic wave shielding light transmitting window material according to any one of the first to fourth aspects, wherein the light-absorbing layer has a surface roughness Rz of 0.1 to 20 μm.
It is characterized by being.

The surface roughness Rz of the light absorbing layer is 0.1 to 20 μm.
A good antireflection effect can be obtained by performing a matte treatment so as to obtain m.

According to a sixth aspect of the present invention, there is provided the electromagnetic wave shielding light transmitting window material according to any one of the second to fifth aspects, wherein one transparent substrate, an outermost anti-reflection film, the electromagnetic wave shielding film, It is characterized by comprising a laminate in which a near-infrared cut film is laminated and integrated.

This electromagnetic wave shielding light transmitting window material uses only one transparent substrate and is thin and lightweight. In addition, since a near-infrared cut film is provided, it is possible to prevent malfunction of the remote controller due to generation of near-infrared rays. In particular, when the antireflection film is disposed on the outermost layer and the near-infrared cut film is disposed on the rearmost layer, these films will be disposed on both the front and back sides of the transparent substrate, and the transparent substrate will The film is protected by the film, so that the impact resistance is enhanced. In addition, even if the transparent substrate is broken, scattering of the fragments is prevented.

According to a seventh aspect of the present invention, in the electromagnetic wave shielding light transmitting window material according to the sixth aspect, the first portion is formed so as to extend from one surface of the electromagnetic wave shielding film to the other surface at an edge portion of the electromagnetic wave shielding film. Conductive tape is adhered, at least a part of the edge of the antireflection film is recessed from the edge of the electromagnetic wave shielding film, and the edge of the outermost surface of the laminate is The second conductive tape is attached so as to reach the edge of the rearmost surface of the laminate through the end face of the laminate.

With this electromagnetic wave shielding light transmitting window material, conduction between the electromagnetic wave shielding film and the housing can be easily attained simply by assembling it into the housing, and good electromagnetic wave shielding properties can be obtained.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the electromagnetic wave shielding light transmitting window material of the present invention will be described below in detail with reference to the drawings.

First, an example of a method for producing an electromagnetic wave shielding film used in the present invention will be described with reference to FIG.

For example, a copper foil 11 is prepared as a conductive foil (FIG. 2A), and a light absorbing layer 1 is formed on one surface of the copper foil 11.
2 is formed (FIG. 2B). As a method for forming the light absorbing layer 12, there is a method in which a copper alloy such as Cu—Ni is formed into a film and then blackened by a treatment with an acid or an alkali. The blackened surface subjected to the surface treatment by this treatment is roughened, and the surface roughness Rz can be changed depending on the treatment conditions. Further, it can be formed by applying a light-absorbing ink to the copper foil 11 and curing it. Examples of the light-absorbing ink used here include carbon ink, nickel ink, and other dark organic pigments. Is used. This light absorbing layer 12 is then subjected to a method of mechanically roughening the surface 12A, such as shot blasting, or an acid,
Roughening the surface with chemicals such as alkalis, coating the ink with inorganic or organic fine particles mixed in advance, and forming a rough surface to form fine irregularities. To perform a matte treatment (see FIG. 2).
(C)). The thickness of the light absorbing layer 12 varies depending on the material for blackening and the conductivity. However, in order to obtain sufficient electromagnetic wave shielding without impairing the conductivity, the thickness is 1 nm to 10 μm.
m, and in order to sufficiently prevent light scattering, the degree of surface roughening of the surface 12A is determined by the surface roughness R.
It is preferable that z be about 0.1 to 20 μm.

Next, the light-absorbing layer 12 is formed, and the matte-treated surface of the copper foil 11 subjected to the matte treatment is applied to a transparent base film such as a PET (polyethylene terephthalate) film 13 with a transparent adhesive 14. Glue (Fig. 2
(D), (e)).

The thus obtained laminated film is subjected to pattern etching according to a conventional method.
By removing the copper foil 11 on which the light absorbing layer 12 is partially formed, copper / PE as an electromagnetic wave shielding film is removed.
A T laminated etching film 10 is obtained (FIG. 2F).

The exposed surface 14A of the transparent adhesive 14 of the copper / PET laminated etching film 10 thus obtained.
Is an uneven surface on which fine unevenness due to the matte treatment of the light absorbing layer 12 is transferred.

The conductive foil constituting the electromagnetic wave shielding film is not limited to a copper foil, but may be a metal foil such as stainless steel, aluminum, nickel, iron, brass, or an alloy thereof. Is copper, stainless steel, aluminum foil.

If the thickness of such a metal foil is too thin, it is not preferable in terms of handleability and workability of pattern etching. If it is too thick, it affects the thickness of the obtained electromagnetic wave shielding light transmitting window material. It is preferable that the thickness is about 1 to 200 μm because the time required for the etching step is long.

As a method of pattern etching such a metal foil, any method generally used may be used, but photo etching using a resist is preferable. In this case, after a photoresist film is pressed on a metal foil or coated with a photoresist, pattern exposure is performed using a desired mask or the like, and development processing is performed to form a resist pattern. Thereafter, the portion of the metal foil where there is no resist may be removed with an etching solution such as a ferric chloride solution.

When a photoresist film is used, a metal foil on which the photoresist film and the light-absorbing layer have been formed and subjected to a matte treatment, an adhesive sheet of a transparent adhesive and a substrate film are bonded to each other. By laminating in the order of sheet / metal foil / photoresist film and pressing them, these can be laminated and integrated in one step, which is preferable.

According to the pattern etching, the degree of freedom of the pattern is large, and the metal foil can be etched to an arbitrary wire diameter, interval and hole shape. Therefore, there is no moire phenomenon, and the desired electromagnetic wave shielding property and light transmission can be obtained. It is possible to easily form an electromagnetic wave shielding light transmitting window material having a property.

In the present invention, the shape of the etching pattern of the metal foil is not particularly limited. For example, FIG.
3 (c), 3 (d), 3 (e), and 3 (c), grid-like metal foils 10A and 10B each having a rectangular hole M as shown in FIG.
A metal foil 10C in the form of a punched metal having a circular, hexagonal, triangular or elliptical hole M as shown in FIG.
10D, 10E, 10F and the like. In addition to the holes M regularly arranged as described above, the moire phenomenon can be prevented as a random pattern.

In order to secure both the electromagnetic wave shielding property and the light transmittance, the area ratio of the opening portion on the projection surface of the metal foil (hereinafter, referred to as "opening ratio") may be 20 to 90%. preferable.

On the other hand, as a transparent substrate film to which a metal foil such as a copper foil 11 is bonded, in addition to the PET film 13, a resin film described later as a transparent substrate material used in the electromagnetic wave shielding light transmitting window material of the present invention is used. However, it is preferable to use PET, PBT (polybutylene terephthalate), PC, PMMA, or an acrylic film, and to make the thickness of the obtained electromagnetic wave shielding light transmitting window material excessively large. In order to obtain sufficient durability and handleability, the thickness is preferably about 1 to 200 μm.

The transparent adhesive for bonding the transparent base film and the metal foil is exemplified by EV exemplified as the adhesive resin used for the electromagnetic wave shielding light transmitting window material of the present invention.
A or PVB resin or the like can be used, and the same method and conditions can be employed for the method and conditions for forming the sheet and bonding. Also, epoxy, acrylic,
Urethane-based, polyester-based, and rubber-based transparent adhesives can be used, and urethane-based and epoxy-based adhesives are particularly desirable from the viewpoint of etching resistance in the etching step after lamination. The thickness of the adhesive layer by the transparent adhesive 14 is
Preferably it is 1 to 50 μm. This transparent adhesive 14
May be blended with conductive particles described below, if necessary.

Next, an embodiment of the electromagnetic wave shielding light transmitting window material of the present invention will be described in detail with reference to FIG.

FIG. 1 is a schematic sectional view showing an electromagnetic wave shielding light transmitting window material according to an embodiment of the present invention.

The electromagnetic wave shielding light transmitting window material 1 shown in FIG.
The outermost antireflection film 3, the copper / PET laminated etching film 10 as an electromagnetic wave shielding film, the transparent substrate 2, and the near-infrared cut film 5 as the backmost layer are bonded to the bonding intermediate films 4A and 4B serving as an adhesive and the adhesive. The resultant was laminated and integrated using the agent 4C, and a conductive pressure-sensitive adhesive tape 7 (hereinafter, referred to as a “second conductive pressure-sensitive adhesive tape”) was adhered to the end face of the laminate and the front and back edges adjacent to the layered face and integrated. Things. The electromagnetic wave shielding film 10 has a size substantially equal to that of the transparent substrate 2, and has a conductive adhesive tape 8 (hereinafter referred to as a “first conductive adhesive”) so that its edge extends from one surface to the other surface. It is called a tape. "). The first conductive adhesive tape 8 is preferably provided over the entire periphery of the edge of the electromagnetic wave shielding film 10, but may be provided partially, for example, at two opposing edges.

In this electromagnetic wave shielding light transmitting window material 1, an antireflection film 3 and a bonding intermediate film 4 thereunder are provided.
A is slightly smaller than the electromagnetic wave shielding film 10 and the transparent substrate 2, and the antireflection film 3 and the bonding intermediate film 4
The edge of A is slightly receded (for example, about 3 to 20 mm, particularly preferably about 5 to 10 mm) from the edge of the electromagnetic wave shielding film 10 and the transparent substrate 2, and the first conductive material at the periphery of the electromagnetic wave shielding film 10 The portion of the adhesive tape 8 is not covered with the antireflection film 3 and the bonding intermediate film 4A. Therefore, the second conductive pressure-sensitive adhesive tape 7 directly covers the first conductive pressure-sensitive adhesive tape 8, and the electromagnetic-wave shielding film 10 is securely connected via the first and second conductive pressure-sensitive adhesive tapes 8, 7. Conducted.

The near-infrared cut film 5 with the adhesive 4C is also slightly smaller than the transparent substrate 2, and the edge of the near-infrared cut film 5 with the adhesive 4C is slightly (for example, 3 to 20 mm) from the edge of the transparent substrate 2. Particularly preferably, 5 to 10
mm).

In this embodiment, the periphery of the anti-reflection film 3, the adhesive intermediate film 4A, and the near-infrared cut film 5 with the adhesive 4C is formed by the second conductive adhesive tape 7.
However, they may cover the inside of the second conductive adhesive tape 7. In the electromagnetic wave shielding light transmitting window member 1 of FIG. 1, the first conductive adhesive tape 8 and the second
It is necessary to achieve conduction with the conductive adhesive tape 7 of
Regarding the antireflection film 3 and the bonding intermediate film 4A,
Although it is necessary to be smaller than the electromagnetic wave shielding film 10 and the transparent substrate 2 and the edges thereof have to recede, the near-infrared cut film 5 with the adhesive 4C may be the same size as the transparent substrate.

Antireflection film 3 and adhesive intermediate film 4A
Is an electromagnetic shielding film 10 over its entire circumference.
Although it is desirable that the first conductive adhesive tape 8 is provided on the opposed two side edges, it is preferable that only that portion be retreated,
The second conductive adhesive tape 7 may also be provided at the two opposing edges.

In the present invention, constituent materials of the transparent substrate 2 include glass, polyester, polyethylene terephthalate (PET), polybutylene terephthalate, polymethyl methacrylate (PMMA), acrylic plate, polycarbonate (PC), polystyrene, and triacetate film. , Polyvinyl alcohol, polyvinyl chloride,
Polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion-crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane, etc., preferably, glass, PET, PC, PM
MA.

The thickness of the transparent substrate 2 is appropriately determined according to the required characteristics (for example, strength and light weight) depending on the use of the obtained window material, but is usually 0.1 to 10 mm, preferably 1 to 4 mm. Range.

[0049] A black frame coating based on acrylic resin or the like may be provided on the periphery of the transparent substrate 2.

The transparent substrate 2 may be provided with a heat ray reflection coat such as a metal thin film or a transparent conductive film to enhance the functionality.

As the anti-reflection film 3, PET, PC, P
Base film of MMA or the like (thickness is, for example, 25 to 250
(about μm) A single layer film of the following (1) or a laminated film of a high refractive index transparent film and a low refractive index transparent film on 3A, for example, the following (2)
And (5) an antireflection layer 3B formed of a laminated film having a laminated structure as described above. (1) One layer of a transparent film having a lower refractive index than the transparent substrate (2) One layer of a high refractive index transparent film and one layer of a low refractive index transparent film (3) High refractive index transparent A film obtained by alternately laminating two films and two low-refractive-index transparent films in total of four layers. Laminated (5) Laminated three layers alternately in the order of high refractive index transparent film / low refractive index transparent film, for a total of six layers

As the high refractive index transparent film, ITO (tin indium oxide), ZnO or Zn doped with Al is used.
A thin film having a refractive index of 1.8 or more, such as O, TiO ₂ , SnO ₂ , or ZrO, preferably a transparent conductive thin film can be formed. As the high refractive index transparent film, a thin film in which these particles are dispersed in an acrylic or polyester binder may be used. Further, as the low refractive index transparent film, SiO ₂ , MgF
₂ , a thin film made of a low refractive index material such as Al ₂ O _{3 having} a refractive index of 1.6 or less can be formed. As the low refractive index transparent film, a thin film made of a silicon-based or fluorine-based organic material is also suitable. These film thicknesses differ depending on the film configuration, film type, and center wavelength in order to reduce the reflectance in the visible light region due to light interference. However, in the case of a four-layer structure, the first layer on the transparent substrate side (high refractive index) 5 to 50 nm for the second layer (transparent film with low refractive index), 50 to 100 nm for the third layer (transparent film with high refractive index), and 50 for the fourth layer (transparent film with low refractive index). ~
It is formed with a thickness of about 150 nm.

Further, an anti-contamination film may be further formed on the anti-reflection film 3 so as to enhance the surface's anti-staining property. In this case, as the contamination prevention film, a thin film having a thickness of about 1 to 100 nm made of a fluorine-based thin film, a silicon-based thin film, or the like is preferable.

As the near-infrared cut film 5, a coating layer of a near-infrared absorbing material such as a copper-based inorganic material, a copper-based organic material, a cyanine-based, a phthalocyanine-based, a nickel complex-based, and a diimmonium-based material is formed on the base film 5A. One provided with a multilayer coating layer 5B of an inorganic dielectric such as zinc oxide or ITO (indium tin oxide) and a metal such as silver can be used. This base film 5A
Preferably, a film made of PET, PC, PMMA, or the like can be used. This film is
In order to ensure handleability and durability without excessively increasing the thickness of the obtained electromagnetic wave shielding light transmitting window material, one
The thickness is preferably about 0 μm to 1 mm. The thickness of the near-infrared cut coating layer 5A formed on the base film 5A is usually 0.5 to 50 μm.
It is about.

In the present invention, a near-infrared cut layer using preferably two or more kinds of the above-mentioned near-infrared cut materials may be provided, and two or more kinds of coating layers may be mixed or laminated. The base film may be coated separately on both sides, or two or more kinds of near-infrared cut films may be laminated.

In particular, in the present invention, as a near-infrared cut material, a combination of two or more kinds of near-infrared cut materials having different near-infrared cut types as described below is used, without deteriorating the transparency. It is preferable to obtain infrared cut performance (for example, a performance of sufficiently absorbing near infrared rays in a wide wavelength range of near infrared rays such as 850 to 1250 nm). (A) ITO coating layer having a thickness of 100 to 5000 （(b) Coating layer formed by alternating lamination of ITO and silver having a thickness of 100 to 10000 （(c) Nickel complex system and immonium system having a thickness of 0.5 to 50 μm (D) Coating layer formed by using a suitable transparent binder with a copper compound containing divalent copper ions having a thickness of 10 to 10000 microns (e). ) 0.5-50 micron thick organic dye coating layer

In the above, a combination of (a) and (c), a combination of (a) and (d), a combination of (b) and (c), a combination of (b) and (d), or only (c) is preferable. There is, but is not limited to these.

In the present invention, a transparent conductive film may be further laminated together with the near-infrared cut film 5, for example. As the transparent conductive film, a resin film in which conductive particles are dispersed or a base film having a transparent conductive layer formed thereon can be used.

The conductive particles to be dispersed in the film are not particularly limited as long as they have conductivity, and examples thereof include the following. (i) Carbon particles or powder (ii) Nickel, indium, chromium, gold, vanadium, tin, cadmium, silver, platinum, aluminum, copper, titanium, cobalt, lead and other metals or alloys or conductive oxides thereof Particles or powder (iii) Plastic particles such as polystyrene, polyethylene, etc. with a coating layer of the conductive material of (i) or (ii) formed on the surface thereof (iv) Alternating laminate of ITO and silver

The particle size of these conductive particles is preferably 0.5 mm or less, since an excessively large particle size would affect the light transmittance and the thickness of the transparent conductive film. The preferred particle size of the conductive particles is 0.01 to 0.5 mm.

When the mixing ratio of the conductive particles in the transparent conductive film is too large, the light transmittance is impaired, and when the mixing ratio is too small, the electromagnetic wave shielding property is insufficient. The proportion is preferably about 0.1 to 50% by weight, particularly about 0.1 to 20% by weight, especially about 0.5 to 20% by weight.

The color and gloss of the conductive particles are appropriately selected according to the purpose. However, from the use as a filter of a display panel, a dark and matte black or brown color is preferred. In this case, by adjusting the light transmittance of the filter appropriately by the conductive particles, there is also an effect that the screen becomes easy to see.

Examples of the base film having a transparent conductive layer formed thereon include a transparent conductive layer formed of tin indium oxide, zinc aluminum oxide, or the like formed by vapor deposition, sputtering, ion plating, CVD, or the like. . In this case, if the thickness of the transparent conductive layer is less than 0.01 μm, the thickness of the conductive layer for shielding electromagnetic waves is too thin,
Sufficient electromagnetic wave shielding properties cannot be obtained, and if it exceeds 5 μm, light transmittance may be impaired.

As the matrix resin of the transparent conductive film or the resin of the base film, polyester, PET, polybutylene terephthalate, PMMA,
Acrylic plate, PC, polystyrene, triacetate film, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane, etc. Preferably, PET, PC and PMMA are mentioned.

The thickness of such a transparent conductive film is
Usually, it is about 1 μm to 5 mm.

The bonding intermediate film 4 for bonding the antireflection film 3, the electromagnetic wave shielding film 10, and the transparent substrate 2
The thermosetting resin constituting A and 4B is preferably a transparent and elastic resin, for example, a resin which is usually used as an adhesive for laminated glass. In particular, as bonding intermediate films 4A and 4B arranged on the front side of the transparent substrate 2,
It is effective to use an elastic film having high scattering prevention ability.

Specific examples of the resin of the film having elasticity include ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene- (meth)
Acrylic acid copolymer, ethylene-ethyl (meth) acrylate copolymer, ethylene-methyl (meth) acrylate copolymer, metal ion crosslinked ethylene- (meth) acrylic acid copolymer, partially saponified ethylene-vinyl acetate Copolymer, carboxylethylene-vinyl acetate copolymer, ethylene-
Ethylene-based copolymers such as (meth) acryl-maleic anhydride copolymer and ethylene-vinyl acetate- (meth) acrylate copolymer may be mentioned ("(meth) acryl" means "acryl or methacryl"). Shown). In addition, polyvinyl butyral (PVB) resin, epoxy resin, acrylic resin, phenol resin, silicone resin, polyester resin, urethane resin, etc. can also be used, but the most balanced in terms of performance and the easy-to-use one is ethylene-vinyl acetate It is a copolymer (EVA). Further, PVB resins used in laminated glass for automobiles are also suitable in terms of impact resistance, penetration resistance, adhesiveness, transparency and the like.

The PVB resin contains 70 to 95% by weight of a polyvinyl acetal unit, 1 to 15% by weight of a polyvinyl acetate unit, and has an average degree of polymerization of 200 to 3000, preferably 3 to 5%.
It is preferably from 00 to 2500, and the PVB resin is used as a resin composition containing a plasticizer.

Examples of the plasticizer for the PVB resin composition include organic plasticizers such as monobasic acid esters and polybasic acid esters, and phosphoric acid plasticizers.

The monobasic acid esters include butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptanoic acid, n-octylic acid, 2-ethylhexylic acid, pelargonic acid (n-
Esters obtained by the reaction of an organic acid such as nonylic acid) and decylic acid with triethylene glycol, and more preferably triethylene-di-2-ethylbutyrate and triethylene glycol-di-2-ethylhexo. Ethates, triethylene glycol-di-capronate, triethylene glycol-di-n-octoate and the like. Note that an ester of the above organic acid with tetraethylene glycol or tripropylene glycol can also be used.

The polybasic acid ester plasticizer is preferably, for example, an ester of an organic acid such as adipic acid, sebacic acid or azelaic acid and a linear or branched alcohol having 4 to 8 carbon atoms, more preferably. , Dibutyl sebacate, dioctyl azelate, dibutyl carbitol adipate and the like.

Examples of the phosphoric acid plasticizer include tributoxyethyl phosphate, isodecylphenyl phosphate, triisopropyl phosphate and the like.

In the PVB resin composition, if the amount of the plasticizer is small, the film-forming property is reduced, and if the amount is large, the durability at the time of heat resistance is impaired. Therefore, the plasticizer is added in an amount of 5 to 100 parts by weight of the polyvinyl butyral resin. 50 parts by weight, preferably 10-4
0 parts by weight.

The PVB resin composition may further contain additives such as a stabilizer, an antioxidant, and an ultraviolet absorber for preventing deterioration.

In the present invention, in particular, as the adhesive resin, a cross-linkable thermosetting resin containing a cross-linking agent, in particular, a cross-linked E
VA resin is preferred.

Hereinafter, a cross-linked EV as the adhesive resin will be described.
The resin A will be described in detail.

The EVA has a vinyl acetate content of 5 to 5
0% by weight, preferably 15-40% by weight is used. If the vinyl acetate content is less than 5% by weight, there is a problem in weather resistance and transparency, and if it exceeds 40% by weight, mechanical properties are remarkably deteriorated, film formation becomes difficult, and film mutual blocking occurs. .

As the crosslinking agent, an organic peroxide is suitable, and is selected in consideration of sheet processing temperature, crosslinking temperature, storage stability and the like. Examples of usable peroxides include, for example, 2,
5-dimethylhexane-2,5-dihydroperoxide; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane-3; di-t-butyl peroxide; t-butylcumyl peroxide; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane; dicumyl peroxide; α, α'-bis (t-butylperoxyisopropyl) benzene; n-butyl-4,4
-Bis (t-butylperoxy) valerate; 2,2-
Bis (t-butylperoxy) butane; 1,1-bis (t-butylperoxy) cyclohexane; 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane; t-butylper Oxybenzoate;
Benzoyl peroxide; tert-butyl peroxyacetate; 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexyne-3; 1,1-bis (tert-butylperoxy) -3,3 5-trimethylcyclohexane; 1,1-bis (tert-butylperoxy) cyclohexane; methyl ethyl ketone peroxide; 2,5-dimethylhexyl-2,5-bisperoxybenzoate; tert-butyl hydroperoxide; p-menthanhydro Peroxide; p-chlorobenzoyl peroxide; tertiary butyl peroxyisobutyrate; hydroxyheptyl peroxide; chlorohexanone peroxide and the like. These peroxides may be used alone or in combination of two or more, usually 10 parts by weight or less, preferably 0.1 to 1 part by weight based on 100 parts by weight of EVA.
Used in a proportion of 0 parts by weight.

The organic peroxide is usually extruded to EVA,
It is kneaded by a roll mill or the like, but may be dissolved in an organic solvent, a plasticizer, a vinyl monomer or the like, and added to the EVA film by an impregnation method.

In order to improve the physical properties (mechanical strength, optical properties, adhesion, weather resistance, whitening resistance, cross-linking speed, etc.) of EVA, various acryloxy or methacryloxy and allyl group-containing compounds are added. be able to. As the compound used for this purpose, acrylic acid or methacrylic acid derivatives, for example, esters and amides thereof are the most common, and ester residues include methyl, ethyl, dodecyl, stearyl, lauryl and other alkyl groups, as well as cyclohexyl groups. , A tetrahydrofurfuryl group, an aminoethyl group, a 2-hydroxyethyl group, a 3-hydroxypropyl group, and a 3-chloro-2-hydroxypropyl group. Further, esters with polyfunctional alcohols such as ethylene glycol, triethylene glycol, polyethylene glycol, trimethylolpropane, and pentaerythritol can also be used. As the amide, diacetone acrylamide is typical.

More specifically, polyfunctional esters such as acrylic or methacrylic esters such as trimethylolpropane, pentaerythritol and glycerin, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, diallyl isophthalate, and maleic Allyl group-containing compounds, such as diallyl acid, are listed. These may be used alone or as a mixture of two or more.
0.1 to 2 parts by weight, preferably 0.5 to 0 parts by weight
To 5 parts by weight.

With such a crosslinked EVA resin,
In bonding the electromagnetic wave shielding film 10 to the transparent substrate 2, they are laminated via the bonding intermediate film 4 </ b> B, and after temporary compression bonding (after this temporary compression bonding, it is possible to re-apply as appropriate). By applying pressure and heating, as shown in FIG. 4, the electromagnetic wave shielding film 10 and the transparent substrate 2 can be bonded to each other without leaving air bubbles, and therefore, the transparent bonding of the electromagnetic wave shielding film 10 can be performed. The adhesive resin 4B 'of the bonding intermediate film 4B is wrapped around the fine irregularities on the surface 14A of the agent 14 to completely fill it, and it is possible to reliably prevent light scattering due to the irregularities.
preferable.

In this way, with the adhesive resin 4B 'of the adhesive intermediate film 4B, the scattering of light due to the fine irregularities on the surface 14A of the transparent adhesive 14 of the electromagnetic wave shielding film 10 is more reliably prevented. In order for this transparent adhesive 1
The refractive index of the transparent adhesive 14 and the cured adhesive resin 4B ′ are set so that light reflection does not occur at the interface between the transparent resin 4 and the adhesive resin 4B ′.
Are preferably approximately equal.

Therefore, since the refractive index of the EVA resin as the adhesive resin 4B 'is approximately n = 1.5,
Preferably, the transparent adhesive 14 has a refractive index of about n = 1.5. Examples of such a transparent adhesive 14 include an epoxy-based, acrylic-based, and urethane-based adhesive in addition to an EVA or PVB resin-based adhesive. , Polyester-based, and rubber-based transparent adhesives.

The thickness of the bonding intermediate films 4A and 4B is
For example, the thickness is preferably about 10 to 1000 μm.

The near-infrared cut film 5 is preferably laminated on the transparent substrate 2 using the adhesive 4C. This is because the near-infrared cut film 5 is vulnerable to heat and has a heat crosslinking temperature (13
0 to 150 ° C.). In addition, if it is a low temperature crosslinking type EVA (crosslinking temperature of about 70 to 130 ° C.), it can be used for bonding the near infrared cut film 5 to the transparent substrate 2.

The bonding interlayers 4A and 4B may further contain a small amount of an ultraviolet absorber, an infrared absorber, an antioxidant, and a paint processing aid, and may be used to adjust the color of the filter itself. Colorants such as dyes and pigments, and fillers such as carbon black, hydrophobic silica, and calcium carbonate may be added in appropriate amounts.

As means for improving the adhesiveness, means such as corona discharge treatment, low-temperature plasma treatment, electron beam irradiation, and ultraviolet light irradiation on the surface of the bonding intermediate film formed into a sheet are also effective.

The adhesive intermediate film is prepared by mixing an adhesive resin and the above-mentioned additives, kneading the mixture with an extruder, a roll, or the like, and then forming the mixture into a predetermined shape by a film forming method such as calendar, roll, T-die extrusion, or inflation. It is manufactured by forming a sheet. During film formation, embossing is applied to prevent blocking and facilitate degassing during pressure bonding with a transparent substrate.

As the bonding intermediate film 4A, a pressure-sensitive adhesive (pressure-sensitive adhesive) is preferably used in addition to the above-mentioned adhesive.
This adhesive and the adhesive 4C of the near-infrared cut film 5
For example, acrylic elastomers, thermoplastic elastomers such as SBS, SEBS and the like are preferably used. These adhesives include tackifiers, UV absorbers, coloring pigments,
A coloring dye, an antioxidant, an adhesion-imparting agent, and the like can be appropriately added. The pressure-sensitive adhesive can be previously coated or bonded to the adhesive surface of the antireflection film 3 or the near-infrared cut film 5 with a thickness of 5 to 100 μm, and can be bonded to a transparent substrate or another film.

As shown in the figure, the second and first conductive adhesive tapes 7 and 8 are provided with adhesive layers 7B and 8A in which conductive particles are dispersed on one surface of metal foils 7A and 8A. The adhesive layers 7B and 8B may be made of an acrylic, rubber, or silicone adhesive, or a mixture of an epoxy or phenolic resin and a curing agent.

As the conductive particles dispersed in the adhesive layers 7B and 8B, various types of conductive particles may be used as long as they are electrically good conductors. For example, metal powder such as copper, silver, and nickel, and resin or ceramic powder coated with such a metal can be used. There is no particular limitation on the shape, and any shape such as a scale shape, a tree shape, a granular shape, and a pellet shape can be adopted.

The amount of the conductive particles was determined according to the adhesive layer 7B,
It is preferably 0.1 to 15% by volume with respect to the polymer constituting 8B, and the average particle size thereof is 0.1 to 10%.
It is preferably 0 μm. As described above, by defining the blending amount and the particle size, it is possible to prevent the conductive particles from condensing and obtain good conductivity.

As the metal foils 7A and 8A serving as the base material of the conductive adhesive tapes 7 and 8, foils such as copper, silver, nickel, aluminum and stainless steel can be used. １００100 μm.

The adhesive layers 7B, 8B are made of the metal foils 7A, 8
A, easily formed by applying a mixture obtained by uniformly mixing the pressure-sensitive adhesive and the conductive particles at a predetermined ratio with a roll coater, a die coater, a knife coater, a my cover coater, a flow coater, a spray coater, or the like. can do.

The thickness of the adhesive layers 7B and 8A is usually about 5 to 100 μm.

The electromagnetic wave shielding light transmitting window material 1 shown in FIG.
In order to manufacture, for example, the antireflection film 3, the electromagnetic wave shielding film 10, the transparent substrate 2, the near-infrared cut film 5 with the adhesive 4C, the bonding intermediate films 4A and 4B, and the first and second films The conductive adhesive tapes 8 and 7 are prepared, and the first conductive adhesive tape 8 is fastened to the periphery of the electromagnetic wave shielding film 10 in advance, and the anti-reflection film 3 and the electromagnetic wave shielding film with the first conductive adhesive tape 8 are attached. 10,
The transparent substrates 2 are laminated with the bonding intermediate films 4A and 4B interposed therebetween, and are integrated by heating under pressure under the curing condition of the bonding intermediate film. Next, the near-infrared cut film 5 is bonded with the adhesive 4C. Thereafter, the second conductive pressure-sensitive adhesive tape 7 is fastened to the periphery of the laminate, and is adhered and fixed by heat compression or the like in accordance with the method of curing the pressure-sensitive adhesive layers 7B, 8B of the conductive pressure-sensitive adhesive tapes 7, 8 used.

When a cross-linked conductive pressure-sensitive adhesive tape is used for the conductive pressure-sensitive adhesive tapes 7 and 8, it is attached to an electromagnetic wave shielding film or a laminate using the adhesiveness of the adhesive layers 7B and 8B. (This temporary fixing can be re-attached if necessary.) Then, heating or ultraviolet irradiation is performed while applying pressure as necessary. Heating may be performed at the same time as the ultraviolet irradiation. In addition, by locally performing the heating or the light irradiation, it is possible to adhere only a part of the cross-linkable conductive adhesive tape.

The heat bonding can be easily performed by a general heat sealer. As a method of heating under pressure, a laminate having a cross-linked conductive pressure-sensitive adhesive tape adhered thereto is placed in a vacuum bag and degassed. The method of heating may be used, and the bonding can be performed very easily.

The bonding conditions are as follows in the case of thermal crosslinking:
Although it depends on the type of the crosslinking agent (organic peroxide) to be used, it is usually 70 to 150 ° C, preferably 70 to 130 ° C, and usually 10 seconds to 120 minutes, preferably 20 seconds to 60 minutes.

In the case of photocrosslinking, the light source is ultraviolet to
Many light sources that emit light in the visible region can be used, and examples thereof include ultra-high pressure, high pressure, low pressure mercury lamps, chemical lamps, xenon lamps, halogen lamps, mercury halogen lamps, carbon arc lamps, incandescent lamps, and laser light.
The irradiation time is not generally determined depending on the type of the lamp and the intensity of the light source, but is usually several tens seconds to several tens of minutes. After heating to 40 to 120 ° C. in advance to promote cross-linking, this may be irradiated with ultraviolet rays.

The pressing force at the time of bonding is also appropriately selected, and is usually 5 to 50 kg / cm ² , especially 10 to 30 kg / cm ² .
/ Cm ² is preferable.

The electromagnetic wave shielding light transmitting window material 1 to which the conductive adhesive tapes 7 and 8 are attached in this manner can be very simply and easily incorporated into a housing. Good conduction between the electromagnetic wave shielding film 10 and the housing can be obtained via the second conductive adhesive tapes 7 and 8. Therefore, a good electromagnetic wave shielding effect can be obtained. In addition, in the presence of the near infrared cut film 5, good near infrared cut performance is obtained.
Furthermore, since there is only one transparent substrate 2, it is thin and lightweight. Further, since both surfaces of the transparent substrate 2 are covered with the films 3 and 5, cracking of the transparent substrate 2 is prevented, and scattering of the transparent substrate 2 in the event of a crack is prevented.

Further, the electromagnetic wave shielding film 10
Is based on pattern etching of a conductive foil such as the copper foil 11, so that the design of the etching pattern is arbitrarily adjusted so that both the electromagnetic wave shielding property and the light transmittance are good, and the problem of the moire phenomenon also occurs. Can be eliminated. The electromagnetic wave shielding film 10 has a light absorbing layer 12, and fine irregularities are formed on the surface of the light absorbing layer 12 by a roughening process, and the transparent adhesive is transferred to the irregularities. Since the unevenness on the surface of the agent 14 is filled with the adhesive resin, the antireflection effect is high, and a clear image with high contrast can be obtained.

The electromagnetic shielding light transmitting window material shown in FIG. 1 is an example of the electromagnetic shielding light transmitting window material of the present invention, and the present invention is not limited to the illustrated one.

The electromagnetic wave shielding light transmitting window material of the present invention is very suitable as a front filter of a PDP or a window material of a place where precision equipment is installed such as a hospital or a laboratory.

[0107]

As described in detail above, according to the present invention, in addition to having excellent electromagnetic wave shielding properties, a high antireflection effect, and excellent transparency and visibility, a clear image can be obtained. An electromagnetic wave shielding light transmitting window material useful as a front filter or the like is provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of an electromagnetic wave shielding light transmitting window material of the present invention.

FIG. 2 is an explanatory view showing one example of a method for producing an electromagnetic wave shielding film used in the present invention.

FIG. 3 is a plan view showing a specific example of an etching pattern.

FIG. 4 is an enlarged cross-sectional view illustrating an adhesive portion between an electromagnetic wave shielding film and a transparent substrate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electromagnetic wave shielding light transmission window material 2 Transparent substrate 3 Antireflection film 4A, 4B Adhesive interlayer 4C Adhesive 5 Near infrared cut film 7, 8 Conductive adhesive tape 7A, 8A Metal foil 7B, 8B Adhesive layer 10 Electromagnetic shield Functional film (copper / PET laminated etching film) 11 Copper foil 12 Light absorbing layer 13 PET film 14 Transparent adhesive

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H04N 5/64 541 G02B 1/10 A H05K 9/00 Z (72) Inventor Tetsuo Kitano 3 Ogawa Higashicho, Kodaira-shi, Tokyo -3-6 (72) Inventor Taichi Kobayashi 3-3-6 (72) Inventor Hidefumi Kotsubo 3-2-7 Ogawa Higashicho, Kodaira City, Tokyo F-term (reference) 2H048 CA05 CA12 2K009 AA02 AA12 BB14 CC09 CC14 CC34 DD01 DD12 EE03 5E321 AA23 AA46 BB24 BB41 BB44 CC16 GG05 GH01 5G435 AA01 AA07 BB06 CC09 GG11 GG33 GG34 GG43 HH03 HH05 HH12 HH14 KK07

Claims (7)

[Claims] 1. An electromagnetic wave shielding light transmitting window material obtained by laminating and integrating at least an electromagnetic wave shielding film and a transparent substrate, wherein the electromagnetic wave shielding film comprises: a transparent base film;
A conductive foil adhered to the transparent substrate side of the base film with a transparent adhesive and pattern-etched, and a light absorption layer for preventing reflection is provided on the base film side of the foil. A light-transmitting window material having electromagnetic wave shielding properties, wherein a layer is provided, and a surface of the light absorbing layer on the side of the base film is roughened. 2. The electromagnetic wave shielding light transmitting window according to claim 1, wherein the electromagnetic wave shielding film has a surface on the conductive foil side bonded to the transparent substrate with a thermosetting resin. Wood. 3. The electromagnetic wave shielding light transmitting window material according to claim 2, wherein said thermosetting resin is a crosslinked thermosetting resin containing a crosslinking agent. 4. The electromagnetic wave shielding light transmitting window according to claim 2, wherein the cured thermosetting resin and the transparent adhesive of the electromagnetic wave shielding film have substantially the same refractive index. Wood. 5. The light-absorbing layer according to claim 1, wherein a surface roughness Rz of the roughened surface is 0.1.
An electromagnetic wave shielding light transmitting window material having a thickness of about 20 μm. 6. The method according to claim 2, wherein one transparent substrate, an outermost antireflection film, the electromagnetic wave shielding film, and a near infrared cut film are laminated and integrated. An electromagnetic wave shielding light transmitting window material comprising a laminate. 7. The method according to claim 6, wherein a first conductive tape is attached to an edge of the electromagnetic wave shielding film so as to extend from one surface to the other surface of the electromagnetic wave shielding film. At least a part of the edge of the antireflection film is recessed from the edge of the electromagnetic wave shielding film, and from the edge of the outermost surface of the laminate, through the end surface of the laminate, and the rearmost surface of the laminate. Characterized in that a second conductive tape is attached so as to reach an edge of the electromagnetic wave shielding light transmitting window material.