JP2002341780A - 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 with a cohesive film, a transparent substrate 2, and a near IR cut film 5 having an intermediate film 4B for adhesion and a pressure sensitive adhesive 4C, and then covering the peripheral edge part with a conductive cohesive tape 7. A conductive cohesive tape 8 is stuck to the peripheral edge of the film 10' having shielding property against electromagnetic waves with the cohesive film and to the peripheral edge of the transparent substrate 2. The film 10' is produced by adhering a conductive foil 11 to a transparent base film 13 with a transparent adhesive 14, pattern etching, forming a light absorbing layer 12 and subjecting the surface of the light absorbing layer 12 to roughening treatment for antireflection and non-gloss treatment. The surface subjected to the antireflection and non-gloss treatment is filled with the transparent pressure sensitive adhesive 15.

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
A transparent substrate film, comprising a conductive foil subjected to pattern etching, which is adhered to a surface of the substrate film opposite to the transparent substrate by a transparent adhesive, and the substrate film of the foil and A light absorption layer for preventing reflection is provided on the opposite surface, and a surface of the light absorption layer opposite to the base film 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 above-described electromagnetic wave shielding film comprising the light absorbing layer subjected to the matte treatment, the foil subjected to the pattern etching, and the base film is produced, for example, by the following procedure. The metal foil is adhered to the transparent base film with a transparent adhesive. Is subjected to pattern etching. A light absorbing layer is formed on the surface of the patterned metal foil, and the surface of the light absorbing layer is roughened.

According to a second aspect of the present invention, there is provided an electromagnetic wave shielding light transmitting window material, wherein a coating film of a transparent adhesive is formed on a surface of the electromagnetic wave shielding film on the conductive foil side. This transparent pressure-sensitive adhesive can be re-applied, and the electromagnetic wave shielding film and the member on the front side can be bonded and integrated without leaving bubbles at the bonding interface.

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 transparent adhesive and the transparent adhesive of the electromagnetic wave shielding film have substantially the same refractive index. It is. By making the refractive indices of the transparent adhesive and the transparent adhesive substantially equal,
Light scattering at the interface between the transparent pressure-sensitive adhesive and the transparent adhesive can be reliably prevented.

According to a fourth aspect of the present invention, there is provided an electromagnetic wave shielding light transmitting window material according to any one of the first to third aspects, wherein a surface roughness Rz of the roughened surface of the light absorbing layer is 0.1 to 20 μm.
It is characterized by being. A good antireflection effect can be obtained by performing a matte treatment so that the surface roughness Rz of the light absorbing layer becomes 0.1 to 20 μm.

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 one transparent substrate, an outermost antireflection film, the transparent substrate and the antireflection film are provided. The electromagnetic wave shielding film interposed between the film and the film and a near-infrared cut film are 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 sixth aspect of the present invention, in the electromagnetic wave shielding light transmitting window material according to the fifth aspect, the transparent substrate and the edge of the electromagnetic wave shielding film adhered to the transparent substrate are provided on the edge of the electromagnetic wave shielding film from the surface of the electromagnetic wave shielding film. A first conductive tape is attached so as to wrap around the back surface of the transparent substrate, and at least a part of an edge of the antireflection film is recessed from an edge of the electromagnetic wave shielding film. A second conductive tape is attached so as to reach the edge of the outermost surface of the laminate from the edge of the outermost surface to the edge 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.

[0020]

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 the copper foil 11 is adhered to a transparent base film such as a PET (polyethylene terephthalate) film 13 with a transparent adhesive 14 ( FIG. 2 (b).

The laminated film thus obtained is subjected to pattern etching to partially remove the copper foil 11 (FIG. 2C).

Next, the patterned copper foil 11
(FIG. 2D). 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 depends on the treatment conditions.
Can be changed. 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. The light-absorbing layer 12 is then subjected to a method of mechanically roughening the surface 12A of the surface 12A by shot blasting, a method of roughening the surface with a chemical such as an acid or an alkali, or a method of mixing inorganic or organic fine particles in ink beforehand. The resulting material is coated and roughened by, for example, a method of forming a coating film with a rough surface to form fine irregularities, thereby performing a matte treatment (FIG. 2E). The thickness of the light absorbing layer 12 varies depending on the material for blackening and the conductivity. However, in order to obtain a sufficient electromagnetic wave shielding property without impairing the conductivity, the thickness of the light absorbing layer 12 is set to one.
The thickness is preferably about 10 nm to 10 μm, and in order to sufficiently prevent scattering of light, the degree of surface roughening of the surface 12 </ b> A is preferably about 0.1 to 20 μm in terms of surface roughness Rz.

Next, the thus obtained copper / PE
A transparent adhesive is applied to the surface of the T-laminated etching film 10 on the side of the copper foil 11 to form a coating film 15 to obtain an electromagnetic wave shielding film 10 'with an adhesive film (FIG. 2 (f)).

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 the metal foil is too small, it is not preferable in terms of handleability and workability of pattern etching. If the thickness is too large, the thickness of the obtained electromagnetic wave shielding light transmitting window material is affected. 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, the photoresist film and the metal foil, the adhesive sheet of the transparent adhesive and the base film are combined with the base film / adhesive sheet / metal foil /
By laminating in the order of the photoresist film and crimping,
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, an interval and a 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 base film to which a metal foil such as a copper foil 11 is adhered, 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 substrate 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.

As the transparent adhesive applied to the copper / PET laminated etching film 10, various transparent pressure-sensitive adhesives can be used.
Thermoplastic elastomers such as S and SEBS are preferably used. These adhesives include tackifiers,
An ultraviolet absorber, a coloring pigment, a coloring dye, an antioxidant, an adhesion-imparting agent, and the like can be appropriately added.

It should be noted that the refractive index of the transparent adhesive 14 and the refractive index of the transparent adhesive of the coating film 15 are adjusted so that no light is reflected at the interface between the transparent adhesive 14 and the transparent adhesive of the coating film 15. Preferably, they are approximately equal.

Accordingly, in general, the refractive index of acrylic or silicon as a transparent pressure-sensitive adhesive is generally about n = 1.5, so that the refractive index of the transparent adhesive 14 is n = 1.5.
It is preferable to use a transparent adhesive such as acrylic, urethane, or rubber.

The thickness of the coating film 15 formed by such a transparent adhesive is preferably about 1 to 100 μm.

In the production of the electromagnetic wave shielding light-transmitting window material, the transparent adhesive film 15 is coated with a conductive adhesive tape to be described later so that the copper foil 11 is exposed. It is provided in a part other than the periphery.

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.
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.
An outermost anti-reflection film 3, an electromagnetic wave shielding film 10 'with an adhesive film, an adhesive intermediate film 4B serving as an adhesive,
The transparent substrate 2 and the near-infrared cut film 5 with the adhesive 4C of the rearmost layer are laminated and integrated, and a conductive adhesive tape 7 (hereinafter referred to as “second conductive material”) is attached to the end face of the laminate and the front and back edges adjacent thereto. It is called an adhesive tape. "). The electromagnetic wave shielding film with an adhesive film 10 ′ has substantially the same size as the transparent substrate 2, and the edge of the laminate of the electromagnetic wave shielding film with an adhesive film 10 ′, the intermediate film for bonding 4 B and the transparent substrate 2. The conductive adhesive tape 8 extends from one surface to the other surface.
(Hereinafter referred to as “first conductive adhesive tape”). The first conductive adhesive tape 8 is preferably provided over the entire periphery of the edge of the laminated body of the electromagnetic wave shielding film with an adhesive film 10 ′ and the transparent substrate 2. It may be provided at the edge.

In this electromagnetic wave shielding light transmitting window material 1, the antireflection film 3 is slightly smaller than the electromagnetic wave shielding film 10 'with an adhesive film and the transparent substrate 2,
The edge of the antireflection film 3 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 with an adhesive film 10 ′ and the edge of the transparent substrate 2. Film 10 '
Are not covered with the antireflection film 3. Therefore, the second conductive adhesive tape 7 directly covers the first conductive adhesive tape 8, and the first conductive adhesive tape 8,
Electromagnetic wave shielding film 10 'with an adhesive film is reliably 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 peripheral portions of the anti-reflection film 3 and the near-infrared cut film 5 with the adhesive 4C are not covered with the second conductive adhesive tape 7.
These may cover the inside of the second conductive adhesive tape 7. In the electromagnetic wave shielding light transmitting window material 1 of FIG.
First conductive adhesive tape 8 and second conductive adhesive tape 7
The antireflection film 3 is required to be electrically connected to the electromagnetic wave shielding film 10 ′ with an adhesive film.
Although it is necessary to be smaller than the transparent substrate 2 and the edge portion has to recede, the near-infrared cut film 5 with the adhesive 4C may be the same size as the transparent substrate.

It is desirable that the antireflection film 3 is set back from the edge of the electromagnetic wave shielding film 10 'with an adhesive film and the transparent substrate 2 over the entire periphery thereof. In the case where 8 is provided at the two opposing edges, only that portion is retracted, and the second conductive adhesive tape 7 may also be provided at the opposing two edges.

Electromagnetic wave shielding light transmitting window material 1 shown in FIG.
For example, in order to manufacture an anti-reflection film 3, an electromagnetic wave shielding film 10 'with an adhesive film, a transparent substrate 2, a near-infrared cut film 5 with an adhesive 4C, an adhesive intermediate film 4B, 2 are prepared in advance, the electromagnetic wave shielding film 10 'with the adhesive film and the transparent substrate 2 are laminated via the bonding intermediate film 4B, and the pressure-sensitive adhesive is cured under the curing condition of the bonding intermediate film. , Heating or heating under reduced pressure to integrate.

Then, the first conductive adhesive tape 8 is fixed to the periphery of the laminate. Then antireflection film 3
Is pressed against the transparent adhesive film 15 of the electromagnetic wave shielding film 10 ′ with an adhesive film and pressure-bonded.
The near-infrared cut film 5 is stuck by C. Thereafter, the second conductive adhesive tape 7 is fastened around the laminate, and the adhesive layers 7B, 8 of the used conductive adhesive tapes 7, 8 are fixed.
According to the curing method of B or the like, it is bonded and fixed by heating, pressing or heating under reduced pressure.

When a cross-linked conductive pressure-sensitive adhesive tape is used for the conductive pressure-sensitive adhesive tapes 7 and 8, the tape is adhered to the laminate using the adhesiveness of the pressure-sensitive adhesive layers 7 B and 8 B. It can be re-attached if necessary.) Then, it is heated or irradiated with ultraviolet rays while applying pressure or maintaining a reduced 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 with a general heat sealer. As a method of heating under pressure, a laminate having a cross-linked conductive pressure-sensitive adhesive tape applied thereto is put into a pressure chamber such as an autoclave and heated. Alternatively, the same laminate may be placed in a vacuum bag and heated after deaeration as a heating method under reduced pressure, 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 , particularly 10 to 30 kg.
/ Cm ² is preferable.

The constituent material of the transparent substrate 2 is glass,
Polyester, polyethylene terephthalate (PE
T), polybutylene terephthalate, polymethyl methacrylate (PMMA), acrylic plate, polycarbonate (PC), polystyrene, triacetate film,
Polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion cross-linked ethylene
Methacrylic acid copolymer, polyurethane, cellophane, etc., preferably, glass, PET, PC, PMMA are mentioned.

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

It is to be noted that a black frame coating based on acrylic resin or the like may be provided on the peripheral portion 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

The high refractive index transparent film is made of ITO (tin indium oxide) or ZnO or Al-doped Zn.
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 increase the anti-contamination property of the surface. 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 the 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 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 excessively large, light transmittance is impaired, and when the mixing ratio is excessively small, electromagnetic wave shielding properties are 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 one such as black or brown is preferable. 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 those having 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.

Electromagnetic wave shielding film 1 with adhesive film
As the thermosetting resin constituting the bonding intermediate film 4B for bonding 0 'and the transparent substrate 2, a transparent and elastic resin, for example, a resin which is usually used as an adhesive for laminated glass is preferable. In particular, it is effective to use an elastic film having a high scattering prevention capability as the bonding intermediate film 4B disposed on the front side of the transparent substrate 2.

Specific examples of the resin of the film having such 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.

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

Examples of the phosphate 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 and the like under heat resistance are 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, especially a cross-linked E
VA resin is preferred.

Hereinafter, a crosslinked 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 of EVA (mechanical strength, optical properties, adhesion, weather resistance, whitening resistance, crosslinking speed, etc.), 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 with an adhesive film 10 ′ to the transparent substrate 2, they are laminated via the bonding intermediate film 4 </ b> B, and after the temporary press-bonding (after this temporary press-bonding, it is possible to re-apply as appropriate). ), Pressurizing, heating, or depressurizing or heating, it is possible to bond both the electromagnetic wave shielding film with an adhesive film 10 'and the transparent substrate 2 without leaving bubbles.

The thickness of the bonding intermediate film 4B is preferably, for example, 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 intermediate film 4B may further contain a small amount of an ultraviolet absorber, an infrared absorber, an antioxidant, and a paint processing aid. In addition, a dye, Colorants such as 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 forming the mixture into a predetermined shape by a film forming method such as calender, 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 4B, 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 may be previously coated or bonded to the adhesive surface of the transparent substrate 2 or the near-infrared cut film 5 with a thickness of 5 to 100 μm, and the adhesive may be bonded to the transparent substrate or another film.

As shown in the drawing, the second and first conductive adhesive tapes 7 and 8 have metal foils 7A and 8A provided with adhesive layers 7B and 8A in which conductive particles are dispersed on one surface. 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 of copper, silver, nickel, aluminum, stainless steel, and the like can be used. １００100 μm.

The adhesive layers 7B, 8B are made of the metal foils 7A, 8B.
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 having the conductive adhesive tapes 7 and 8 attached in this manner can be very easily 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.

Moreover, since the electromagnetic wave shielding film 10 'with the adhesive film is formed by pattern etching of a conductive foil such as the copper foil 11, the electromagnetic wave shielding property and the light shielding property can be adjusted by arbitrarily adjusting the design of the etching pattern. Both the light transmittance and the moiré phenomenon can be solved. The electromagnetic wave shielding film with an adhesive film 10 ′ has the light absorbing layer 12, and fine irregularities are formed on the surface of the light absorbing layer 12 by a roughening treatment, and the irregularities are transparent. Since it is filled with the pressure-sensitive adhesive, a high antireflection effect and a clear image with high contrast can be obtained.

That is, as shown in FIG. 4, the coating film 15 of the transparent adhesive was formed on the base film 13 and the transparent adhesive 14 of the electromagnetic wave shielding film 10 ′ with the adhesive film.
The protrusions formed by the copper foil 11 and the light absorption layer 12 are completely filled, and light scattering caused by the protrusions and recesses can be reliably prevented.

In order to prevent the scattering of light with the transparent pressure-sensitive adhesive more reliably, light reflection should not occur at the interface between the transparent pressure-sensitive adhesive film 15 and the transparent adhesive 14. In addition, as described above, it is preferable that the refractive index of the transparent adhesive and the refractive index of the transparent adhesive 14 are substantially equal.

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.

For example, the adhesion between the copper / PET laminated etching film 10 as an electromagnetic wave shielding film and the antireflection film 3 is performed by using a transparent adhesive film 1 formed in advance.
In addition to the above-described step 5, the above-described step may be performed using the above-described bonding intermediate film. Also in this case, it is preferable that the refractive index of the adhesive resin after the curing of the adhesive intermediate film to be used is substantially equal to the refractive index of the base film 13 in order to prevent reflection at these interfaces.

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 precision equipment installation place such as a hospital or a laboratory.

[0108]

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 4B Adhesive interlayer 4C Adhesive 5 Near infrared cut film 7,8 Conductive adhesive tape 7A, 8A Metal foil 7B, 8B Adhesive layer 10 Copper / PET lamination Etching film 10 'Electromagnetic wave shielding film with adhesive film 11 Copper foil 12 Light absorbing layer 13 PET film 14 Transparent adhesive 15 Transparent adhesive coating

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G12B 17/02 H04N 5/66 101Z 5G435 17/04 5/72 A H04N 5/66 101 H05K 9/00 V 5/72 G02B 1/10 A H05K 9/00 Z (72) Inventor Tetsuo Kitano 3-3-6 Ogawa Higashicho, Kodaira City, Tokyo (72) Inventor Taichi Kobayashi 3-3-6 Ogawa Higashicho, Kodaira City, Tokyo (72) Inventor Hidefumi Kotsubo 3-2-7 Ogawa Higashicho, Kodaira City, Tokyo F-term (reference) 2F078 HA14 HA16 2H048 CA04 CA05 CA12 CA24 2K009 AA02 AA05 AA07 AA12 BB14 CC03 CC06 CC14 DD01 DD12 EE03 5C058 AA11 AB05 BA30 DA01 DA08 5E AA04 BB23 BB25 CC16 GG05 GH01 5G435 AA01 AA16 BB06 FF14 GG11 GG33 GG43 HH03 HH05

Claims (6)

[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 pattern-etched conductive foil adhered to a surface opposite to the substrate by a transparent adhesive, and a light absorption layer for reflection prevention is provided on a surface of the foil opposite to the base film. An electromagnetic wave shielding light transmitting window material, wherein a surface of the light absorbing layer opposite to the base film is roughened. 2. The electromagnetic wave shielding light transmitting window material according to claim 1, wherein a coating of a transparent adhesive is formed on a surface of the electromagnetic wave shielding film on the conductive foil side. 3. The electromagnetic wave shielding light transmitting window material according to claim 2, wherein the transparent adhesive and the transparent adhesive of the electromagnetic wave shielding film have substantially the same refractive index. 4. The light-absorbing layer according to claim 1, wherein the surface-roughened surface of the light-absorbing layer has a surface roughness Rz of 0.1.
An electromagnetic wave shielding light transmitting window material having a thickness of about 20 μm. 5. The electromagnetic wave shield according to claim 1, wherein one transparent substrate, an outermost antireflection film, and the electromagnetic wave shield interposed between the transparent substrate and the antireflection film. An electromagnetic wave shielding light transmitting window material comprising a laminate in which a conductive film and a near-infrared cut film are laminated and integrated. 6. The transparent substrate according to claim 5, wherein the transparent substrate and the electromagnetic wave shielding film adhered to the transparent substrate are edged so as to extend from the front surface of the electromagnetic wave shielding film to the rear surface of the transparent substrate. A conductive tape is attached, 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 An electromagnetic wave shielding light transmitting window material, characterized in that a second conductive tape is attached so as to reach an edge of the rearmost surface of the laminate through an end face.