JP2007220789A - Optical filter for display and manufacturing method thereof - Google Patents

Abstract

A metal mesh pattern of an electromagnetic wave shielding layer can be produced by an inexpensive production method based on resource saving, the entire optical filter can be reduced in thickness and weight, and has high electromagnetic wave shielding properties. Provided are an optical filter that is excellent in translucency and capable of obtaining a clear image, and a method for producing the same.
In an optical filter for display 10 provided with an electromagnetic wave shielding material 14, an electromagnetic wave shield comprising a mesh pattern 17 made of a conductive metal such as developed silver and metal plating layers 18a and 18b laminated thereon. The material 14 is attached to one side of the transparent substrate 12 constituting the optical filter 10 on the metal plating layer 18b side by transfer.
[Selection] Figure 1

Description

  The present invention relates to an optical filter used for various displays such as CRT and PDP (plasma display panel). More specifically, the overall thickness of the optical filter for display (hereinafter simply referred to as “optical filter”) can be reduced by reducing the thickness of the optical filter. The present invention relates to an optical filter for display capable of obtaining an excellent and clear image and a method for producing the same.

In recent years, in displays such as CRTs and PDPs (plasma display panels), electromagnetic waves generated from the front of the display have a negative effect on the human body and malfunction of surrounding electronic devices has become a problem. Along with the clearness of the display, countermeasures against the influence of the display on the surroundings are becoming increasingly important.
In particular, in PDPs where demand is increasing as large thin displays, in addition to electromagnetic wave shielding films, near-infrared absorbing films for preventing malfunctions of various remote control switches using the near-infrared wavelength region, UV light absorbing film used to prevent near-infrared absorbers used for near-infrared absorbing film over time, neon light cut film for adjusting color tone in the visible light region, and external light reflected on the surface of optical filters An antireflection film or the like for preventing this is combined and configured according to the required function.
By using these films as optical filters for displays, measures are taken to improve the image appearance and to reduce the influence on the surroundings.

  On the other hand, various transparent conductive films and electromagnetic wave shielding films have been developed in order to prevent the adverse effect of electromagnetic waves generated from a display on the human body due to leakage to the outside. Known electromagnetic shielding materials can be broadly classified into two types: an electromagnetic shielding material made of a transparent conductive film and an electromagnetic shielding material made of a conductive metal mesh. Among these, the electromagnetic shielding material using a transparent conductive film is superior in transparency to the electromagnetic shielding material using a metal mesh, but has a large surface resistivity and inferior electromagnetic shielding performance. For this reason, in the use which shields the electromagnetic waves from the apparatus which generate | occur | produces strong electromagnetic waves, such as PDP, the electromagnetic wave shielding material by a metal mesh is preferable.

Furthermore, as a method for producing an electromagnetic wave shielding material using a conductive metal mesh, the following methods (1) to (3) are exemplified.
(1) An etching method in which a metal foil is bonded to a transparent substrate, or a metal thin film is deposited on the transparent substrate, and then a conductive metal pattern is formed by a photolithographic method (see, for example, Patent Document 1).
(2) A printing-plating method in which a conductive metal paste is printed on a transparent substrate and then plated to form a conductive metal pattern (see, for example, Patent Document 2).
(3) A photographic silver-plating method for forming a conductive metal pattern by forming a fine line pattern with developed silver produced by a photographic method and then plating on the developed silver thin film (for example, Patent Document 3 and (See Patent Document 4).

  And, there are two methods shown in the following (a) and (b) for forming a mesh pattern with developed silver produced by a photographic method.

(A) A silver salt-containing layer containing a silver salt provided on a support is exposed and developed to form a metallic silver part and a light-transmitting part, and the metallic silver part is further subjected to physical development and A method of forming a conductive metal part in which conductive metal particles are supported on the metal silver part by plating (see, for example, Patent Document 3). In this method, developed silver does not appear in the portion that is covered with the exposure mask and is not exposed, and developed silver appears in the portion that is not covered with the exposure mask and exposed. Therefore, compared with the exposure mask. This is a negative exposure / development method in which developed silver appears in an inverted form.

(B) A light-sensitive material having a physical development nucleus layer and a silver halide emulsion layer in this order is exposed on a transparent substrate, and metallic silver is deposited on the physical development nucleus in an arbitrary fine line pattern. A method of plating a metal using the physically developed metallic silver as a catalyst nucleus after removing a layer provided on the development nucleus (see, for example, Patent Document 4). In this method, developed silver appears in a portion which is covered with the exposure mask and is not exposed, and developed silver does not appear in a portion which is not covered with the exposure mask and exposed. Is a positive exposure / development method (silver complex diffusion transfer method, hereinafter referred to as DTR method).

Further, in Patent Documents 5 and 6, unevenness of the copper foil remains on the adhesive layer on the surface of the transparent substrate from which the copper foil has been removed by the etching method, and transmitted light is scattered by the unevenness, thereby transmitting light. In order to solve this problem, it is described that a mesh pattern of copper foil formed by etching is transferred to another support material.
Similarly, in Patent Document 7, two copper foils are bonded together, and a mesh pattern is formed by etching only on a thin copper foil on one side. A method for producing an electromagnetic wave shielding material excellent in translucency by transferring to a protective layer is described.
Japanese Patent Laid-Open No. 10-075087 JP 11-170420 A JP 2004-221564 A International Publication No. 2004/007810 Pamphlet Japanese Patent Laying-Open No. 2005-064280 JP 2004-069931 A Japanese Patent Laid-Open No. 2003-218583

When manufacturing the metal mesh pattern of the electromagnetic wave shielding material incorporated in the optical filter, the etching method (1) above leaves only a small part that becomes a thin line part, and most other metals are etched by etching. Dissolving and removing is a problem from the viewpoint of saving resources. Further, the method of depositing a metal thin film has a problem that it cannot be easily manufactured because a huge equipment cost is required.
The printing-plating method (2) has a problem that it is difficult to make the line width of the metal mesh pattern 30 μm or less. In addition, since the conductive paste contains a binder, there is a problem that only a low conductivity can be obtained only by printing on the substrate using the conductive paste, and high electromagnetic shielding performance cannot be obtained. It was.

  In the photographic silver-plating method of (3) above, high electromagnetic wave shielding performance is obtained, and there is no restriction on the dimensions of the transparent base material, and it can be produced by roll-to-roll, and the productivity is very high. This is a preferred production method.

On the other hand, in various displays, especially PDPs, an antireflection film (AR film) is adopted as the outermost layer as an optical filter to be attached to the display in order to prevent reflection due to external light (outdoor light or indoor illumination light). Yes. However, as a measure for improving the image on the display, only the use of a neon light absorber is disclosed for color correction.
In recent years, in various displays, particularly PDPs, there is an increasing demand for viewing images not only in a dark room but also in a state where the room is brightened by illumination or the like. However, when the room is brightened, a phenomenon occurs in which the image becomes white due to reflection or reflection of external light, and the contrast of black and white is further lowered to blur the image. For this reason, in the PDP, a clear image is displayed without attenuating the emission intensity of the PDP, so that an optical filter having a high total light transmittance and a small decrease in luminance is required. There is also a need for an optical filter that is lightweight and can avoid an increase in weight due to an increase in screen size.

  In any of the methods described in Patent Documents 5 to 7, an extremely thin (thin film thickness of about 5 to 15 μm) copper foil bonded to a base material using an adhesive is formed into a metal mesh pattern by an etching method. The purpose is to solve the problem that the transparent base material is colored by the etching solution such as ferric chloride aqueous solution and cupric chloride aqueous solution by transferring the metal mesh pattern, and to improve the translucency It is. However, when the metal mesh pattern is peeled off from the substrate and transferred to another support material, there is a problem that it is difficult to adjust the adhesive strength of the adhesive that bonds the copper foil and the substrate.

Patent Documents 5 to 7 describe that a metal mesh pattern is transferred, but no disclosure or suggestion is made regarding a method for easily peeling the metal mesh pattern from the substrate.
In addition, the methods described in Patent Documents 5 to 7 are associated with an etching method in which only a small portion that becomes a thin line portion is left, and most of the other metals are dissolved and removed by etching to waste resources. There was a problem that the fundamental problem was not solved at all.
As described above, in the conventional technique, the metal mesh pattern of the electromagnetic wave shielding layer is manufactured on the surface of the first base material by an inexpensive manufacturing method based on resource saving, and the metal mesh pattern is used as another second transparent substrate. An optical filter using an electromagnetic wave shielding material that is easily transferred to a material is not provided.

  The present invention has been made in view of the above circumstances, and can form an electromagnetic wave shielding layer made of a metal mesh pattern by an inexpensive manufacturing method based on resource saving, reducing the overall thickness of the optical filter and reducing the weight. It is an object of the present invention to provide an optical filter that has a high electromagnetic wave shielding property and is excellent in translucency and can obtain a clear image, and a method for producing the same.

  In order to solve the above-mentioned problems, the present invention provides an optical filter for a display in which an electromagnetic wave shielding material is provided, and an electromagnetic wave shielding material comprising a conductive metal mesh pattern and a metal plating layer laminated thereon. An optical filter for display is provided, which is attached to one side of a transparent substrate constituting the optical filter.

The conductive metal mesh pattern is preferably a developed silver mesh pattern generated by a photographic process.
The metal plating layer preferably has an electroless copper plating layer and / or an electrolytic copper plating layer laminated on and in contact with the developed silver mesh pattern.
The developed silver mesh pattern is preferably generated by a positive photographic process or a negative photographic process.
The electromagnetic wave shielding material is preferably a metal mesh having a thickness of 0.5 to 15 μm, a line width of 10 to 50 μm, and an interval between thin lines of 100 to 900 μm.
The surface of the metal plating layer is preferably blackened.
Furthermore, the optical filter preferably has one or more layers among a near-infrared absorbing layer, an ultraviolet absorbing layer, a neon light absorbing layer, a light absorbing material dispersion layer, and an antireflection layer.

  The present invention also relates to a method for producing an optical filter for a display in which an electromagnetic wave shielding material is provided, the mesh pattern generating step of generating a developed silver mesh pattern on a supporting substrate by a photographic method, and the developed silver mesh A plating process for forming an electromagnetic wave shielding material made of a metal mesh with a conductive metal plating layer on the pattern, and the electromagnetic wave shielding material is transferred to one side of a transparent substrate constituting the optical filter by transferring the metal plating layer. And a transfer step of sticking on the side. A method for producing an optical filter for display is provided.

The metal plating layer preferably has an electroless copper plating layer and / or an electrolytic copper plating layer laminated on and in contact with the developed silver mesh pattern.
Between the plating step and the transfer step, the electromagnetic shielding material formed on the supporting substrate is immersed in a strong alkaline solution having a pH of 11 to 13, whereby the adhesion between the electromagnetic shielding material and the supporting substrate is increased. It is preferable to have an alkali treatment step for lowering.
The developed silver mesh pattern is preferably generated by a positive photographic process or a negative photographic process.

  The present invention provides an optical filter comprising producing a mesh pattern of an electromagnetic shielding material by an inexpensive production method based on resource saving, and easily transferring the electromagnetic shielding material onto a transparent substrate. Thus, it is possible to provide an optical filter that can be reduced in weight by reducing the thickness of the entire optical filter, has high electromagnetic shielding properties, and is excellent in translucency and capable of obtaining a clear image.

  By using the method of the present invention, the metal mesh pattern is used for producing the metal mesh pattern as compared with the case where the metal mesh pattern is formed on the transparent substrate in the prior art and is directly bonded to the constituent layer of the optical filter. Since one transparent base film can be omitted, the translucency of visible light can be improved.

In the present invention, since the copper plating layer is laminated by electroless plating and / or electrolytic plating in contact with the developed silver mesh pattern generated by the photographic method, the phenomenon that metal silver diffuses and migrates to the copper plating layer, The adhesion between the developed silver mesh pattern and the supporting substrate is reduced, and the electromagnetic shielding material is lifted from the supporting substrate, and the electromagnetic shielding material is easily peeled from the supporting substrate.
Moreover, since the present invention reduces the adhesion between the electromagnetic shielding material and the supporting substrate by immersing the electromagnetic shielding material formed on the supporting substrate in a strong alkaline solution having a pH of 11 to 13, It becomes easy to peel the electromagnetic wave shielding material from the supporting base material.
For this reason, in the present invention, after the electromagnetic wave shielding material is peeled from the supporting base material and transferred onto the transparent base material, the electromagnetic wave shielding material formed on the supporting base material is pressure-bonded toward the transparent base material. The transfer work of peeling off the electromagnetic wave shielding material whose adhesion with the supporting substrate has been reduced can be performed smoothly.

The present invention will be described below with reference to the drawings based on the best mode.
FIG. 1A is a schematic cross-sectional view showing an example of an optical filter for display according to the present invention, and FIG. 1B is a partially enlarged cross-sectional view showing the layer structure thereof. FIG. 2 is a schematic cross-sectional view showing an example of a laminate in which an electromagnetic wave shielding material is provided on a support base material. FIG. 3A is a schematic cross-sectional view for explaining a state in which the electromagnetic shielding material provided on the supporting base material is transferred onto the transparent base material, and FIG. It is typical sectional drawing explaining a mode that it peels. FIG. 4 is a schematic cross-sectional view showing an example of an optical filter for display according to a conventional method.

  The display optical filter of the present embodiment (hereinafter simply referred to as the optical filter of the present embodiment) can be used by being directly attached to a front panel P of a display such as a plasma display panel (PDP). 1 and 4, the eye E represents the visual side.

The optical filter 10 of this embodiment shown in FIG. 1 includes, in order from the visual side, an antireflection layer 11, a transparent substrate (ultraviolet absorbing layer) 12 to which an ultraviolet absorber is added, and an adhesive layer in which a black pigment is dispersed ( A light absorbing material dispersion layer) 13, an electromagnetic wave shielding material 14, an adhesive layer 15, and an adhesive layer (near infrared absorbing layer) 16 to which a near infrared absorbing agent is added. The electromagnetic wave shielding material 14 sandwiched between the layers 13 and 15 includes a conductive metal mesh pattern 17 and metal plating layers 18a and 18b laminated thereon, and the metal plating layer 18b side is a transparent substrate 12. Attached to one side of the transparent substrate 12 by transfer through the pressure-sensitive adhesive layer 13 so as to face the side.
In the case of the optical filter 10 shown in FIG. 1, the pressure-sensitive adhesive layer 13 in which the black pigment is dispersed functions as a light absorbing material dispersion layer.

  In FIG. 1, an ultraviolet absorber is added to the transparent substrate 12 to form an ultraviolet absorbing layer, and a near infrared absorber is added to the adhesive layer 16 in contact with the front panel P to form a near infrared absorbing layer. Although an example is shown, the combination of the layers employed in the optical filter among the near-infrared absorbing layer, the ultraviolet absorbing layer, the neon light absorbing layer, and the antireflection layer is not particularly limited thereto. For example, the near-infrared absorbing layer may be bonded with a binder resin layer (not shown) to which a near-infrared absorbing agent is added. A neon light absorption layer (not shown) can be realized, for example, by an adhesive layer to which a neon light absorber is added.

(Antireflection layer)
Here, the antireflection layer 11 is for preventing reflection of visible light from the outside of the optical filter 10, and in the case of a single layer, a material having a lower refractive index than the transparent substrate 12, for example, poly A thin film such as a fluorine-containing organic compound having a siloxane structure is formed. In the case of a multi-layer structure, a material having a higher refractive index than that of the transparent substrate 12, for example, a titanium oxide vapor-deposited thin film, and a material having a lower refractive index than that of the transparent substrate, such as a silicon oxide thin film, are alternately laminated. . The formation method of such a metal oxide thin film is not particularly limited, and a thin film of zirconium oxide, ITO, silicon oxide, or the like can be formed by a sputtering method, a vacuum evaporation method, or a wet coating method.
However, in the case of an optical filter for display, since a plurality of films are laminated, reflection occurs at the laminated film interface.
For this reason, since the reflectance of the entire optical filter increases, only the outermost antireflection layer 11 prevents the whitening of the image and the decrease in black-and-white contrast due to the reflection of external light, and the image becomes clear. The current situation is that the problem cannot be solved sufficiently.

(Light absorber dispersion layer)
Therefore, in the present invention, a light absorbing material that absorbs external light that has passed through the antireflection layer 11 is dispersed in the pressure-sensitive adhesive layer 13, so that external light is incident on the inside of the optical filter 10 and the inside of the optical filter 10. Scattered light derived from external light incident on the light is again emitted to the outside of the filter or becomes stray light and interferes with the image on the display. As a result, whitening of the image on the display can be prevented and monochrome contrast can be increased.

(Light absorber)
As the light absorbing material used in the present invention, particles of black pigments such as carbon black, graphite, aniline black, cyanine black, titanium black, black iron oxide, chromium oxide, and manganese oxide can be used. In order to adjust the color tone of the entire optical filter to an achromatic color or a preferable color tone, a plurality of types of light absorbing materials and other color materials may be combined and used as necessary. Of these black pigments, carbon black is particularly preferably used. The preferable particle size distribution range of the black pigment (light absorbing material) is in the range of 0.01 to 0.5 μm, and more preferably in the range of 0.05 to 0.3 μm.
Increasing the amount of black pigment (light absorber) added to increase black and white contrast causes the phenomenon that the total light transmittance decreases and the image becomes dark, so the amount of black pigment (light absorber) added is unlimited. However, it is possible to achieve sufficiently satisfactory black and white contrast by adjusting the addition condition of the black pigment (light absorbing material) according to the allowable total light transmittance.

(Transparent substrate)
The transparent material constituting the transparent substrate 12 is a plastic film made of a resin that is transparent in the visible region, has flexibility, and preferably has good heat resistance.
Examples of such plastic films include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), diacetate resins, triacetate resins, acrylic resins, polycarbonate resins, triacetyl cellulose, polystyrene, polyolefins, polyurethane resins. , A single layer or a composite film having a thickness of 10 to 600 μm made of polyvinyl chloride, polyimide resin, polyamide resin or the like.
In the optical filter, a transparent base material coated with a functional layer such as an antireflection layer, a near infrared ray absorbing layer, an ultraviolet ray absorbing layer, or a neon light absorbing layer can be laminated and exist in the layer structure of the filter. From the viewpoint of suppressing the decrease in the total light transmittance, it is preferable to reduce the number of transparent base layers as much as possible. As such a combined method, a method of sequentially forming a plurality of functional layers on one transparent substrate or transferring a functional layer formed on a release paper can be mentioned.

(Adhesive layer)
The pressure-sensitive adhesive constituting each pressure-sensitive adhesive layer 13, 15, 16 is not particularly limited as long as it is transparent in the visible region (that is, has sufficient transmittance). As long as it is transparent, a curable resin or a thermoplastic resin may be used. Examples of the curable resins include thermosetting resins, ultraviolet curable resins, and electron beam curable resins. Among these curable resins, the equipment for resin curing is simple and excellent in workability. Therefore, an ultraviolet curable resin is preferable. In addition, when the black pigment is directly mixed in the pressure-sensitive adhesive layer, a thermoplastic resin is preferably used.
As the pressure-sensitive adhesive layer, an acrylic copolymer is preferably used from the viewpoint of transparency.

(Adhesive layer with black pigment dispersed)
The light absorbing material dispersion layer in the present invention may be formed by dispersing a black pigment in an adhesive as in the example shown in FIG. The coating thickness of the light absorbing material dispersion layer formed by dispersing the black pigment in the pressure-sensitive adhesive is preferably 2 to 50 μm.
In the present invention, the pressure-sensitive adhesive (transparent resin) used in the light-absorbing material dispersion layer formed by dispersing the black pigment in the pressure-sensitive adhesive may be the above-described various curable resins or thermoplastic resins as long as it is transparent. But it ’s okay. From the viewpoint of transparency, an acrylic copolymer is preferably used.
The above black pigment is uniformly mixed and dispersed in an appropriately selected transparent resin to prepare a light absorbing material dispersion layer composition, and the obtained light absorbing material dispersion layer composition is placed on the transparent substrate 12. In addition, the light-absorbing material dispersion layer 13 can be formed by a known coating method such as a bar coating method, a roll coating method, or a gravure reverse coating method.

In FIG. 1, the pressure-sensitive adhesive layer 13 in which the light absorbing material (black pigment) is dispersed is obtained by dispersing the above-described light absorbing material (black pigment) in a transparent pressure-sensitive adhesive (transparent pressure-sensitive adhesive). Scattered light derived from external light incident on the inside of the optical filter 10 is reduced from being emitted again to the external viewing side of the filter or superposed on the display image as stray light. As a result, whitening of the image on the display can be prevented and monochrome contrast can be increased.
When a light absorbing material is added to the pressure-sensitive adhesive layer 13, the number of layers of the transparent base material can be further reduced as compared with the case where the light absorbing material is dispersed in the transparent base material, thereby suppressing a decrease in the total light transmittance. be able to. In addition, when a large amount of light absorbing material is blended in one pressure-sensitive adhesive layer, the function of the pressure-sensitive adhesive is not preferable, and it may be dispersed in a plurality of pressure-sensitive adhesive layers. Moreover, you may mix | blend a light absorption material with both an adhesive layer and a transparent base material.

(Near-infrared absorbing layer)
The near-infrared absorbing layer can be provided in one layer or a plurality of layers at an appropriate position of the optical filter as necessary. As a method of forming a near infrared absorbing layer, a method of mixing a near infrared absorber in a transparent substrate or a pressure-sensitive adhesive layer, a coating solution containing a near infrared absorber directly or on another transparent substrate The method of apply | coating through a layer is mentioned. As the near-infrared absorber, the near-infrared transmittance in the wavelength region 800 to 1100 nm is 15% or less, preferably 10% or less. Specific examples include immonium salt compounds, diimonium salt compounds, aminium salt compounds, nitroso compounds and their metal complexes, cyanine compounds, squarylium compounds, thiol nickel complex compounds, aminothiol nickel complex compounds, phthalocyanine compounds. Compounds, naphthalocyanine compounds, triarylmethane compounds, naphthoquinone compounds, anthraquinone compounds, amino compounds, carbon black, antimony oxide, tin oxide doped with indium oxide, metals belonging to groups 4, 5 or 6 of the periodic table And oxides, carbides, borides, and the like. These near infrared absorbers can be used alone or in combination of two or more. By providing the near-infrared absorbing layer, it is possible to absorb near-infrared light emitted from the display.

(UV absorbing layer)
If necessary, one or more ultraviolet absorbing layers can be provided at an appropriate position of the optical filter. As a method for forming the ultraviolet absorbing layer, a method in which an ultraviolet absorber is mixed into a transparent substrate or an adhesive layer, a coating solution containing an ultraviolet absorber is applied directly on the transparent substrate or through another layer. For example. The ultraviolet absorbing layer is provided closer to the visual side than the near infrared absorbing layer in order to prevent the near infrared absorbing layer from being deteriorated by external light. As the ultraviolet absorber, either an organic ultraviolet absorber or an inorganic ultraviolet absorber can be used, but the wavelength at 50% transmittance is preferably 350 to 420 nm, more preferably 360 to 400 nm. When the wavelength at the 50% transmittance is lower than 350 nm, the ultraviolet blocking ability is weak, and when the wavelength is higher than 420 nm, the coloring becomes strong.

  Examples of organic ultraviolet absorbers include 2- (2′-hydroxy-5′-t-butylphenyl) benzotriazole, 2- (2-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole, and the like. Benzotriazole compounds, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone and other benzophenone compounds, phenyl salicylate, 4-t-butylphenyl salicylate, 2,5 Hydroxybenzoate compounds such as t-butyl-4-hydroxybenzoic acid n-hexadecyl ester, 2,4-di-t-butylphenyl-3 ', 5'-di-t-butyl-4'-hydroxybenzoate Etc. Examples of inorganic ultraviolet absorbers include titanium oxide, zinc oxide, cerium oxide, iron oxide, and barium sulfate. These ultraviolet absorbers can be used alone or in combination of two or more.

(Neon light absorption layer)
One or more neon light absorbing layers can be provided at an appropriate position of the optical filter as necessary. The neon light absorption layer is for making the red color of an image clearer by removing neon light (absorption wavelength: 580 to 620 nm) emitted from the PDP using a neon light absorber.
As a method of forming a neon light absorbing layer, a method of mixing a neon light absorber in a transparent substrate or an adhesive layer, a coating liquid containing a neon light absorber directly on a transparent substrate or other The method of apply | coating through a layer is mentioned. Examples of the neon light absorber include suitable dyes having a maximum absorption wavelength in the wavelength range of 580 to 620 nm among dyes such as cyanine, squarylium, azomethine, xanthene, oxonol, and azo. It is done. These neon light absorbers can be used alone or in combination of two or more.

(Electromagnetic wave shielding material)
Conventionally, various transparent conductive films and electromagnetic wave shielding films have been developed in response to the requirement that electromagnetic waves generated from a display leak outside and prevent adverse effects on the human body. Known electromagnetic shielding materials can be broadly classified into two types: an electromagnetic shielding material made of a transparent conductive film and an electromagnetic shielding material made of a conductive metal mesh. The electromagnetic shielding material using a transparent conductive film is superior in transparency to the electromagnetic shielding material using a metal mesh, but has a large surface resistivity and inferior electromagnetic shielding performance. Since a plasma display generates a large amount of electromagnetic waves, an electromagnetic shielding material made of a metal mesh is preferable.
Furthermore, as a method for producing a conductive metal mesh, a method using a photographic silver-plating method is superior in that it can achieve both a high electromagnetic shielding effect and high transparency (high total light transmittance), and higher. Since transparency (high total light transmittance) can be obtained, the concentration of black pigment (light absorbing material) can be increased, and the black and white contrast can be further increased.

(Method for manufacturing electromagnetic shielding material)
The method for producing an electromagnetic shielding material used in the present invention is a support base material using any one of two different silver salt photographic development methods (positive photographic method-plating method, negative photographic method-plating method). Form a thin film with fine line mesh pattern made of developed silver generated by photographic process on top of this, and form an electromagnetic shielding material consisting of metal mesh pattern by laminating conductive metal layer by plating on this fine line pattern Then, the electromagnetic shielding material is transferred to a transparent substrate constituting the optical filter. As the developed silver fine line pattern, a mesh, a lattice shape, a comb shape, and other various patterns can be employed without any particular limitation.

  One method of the silver salt photographic development method is a method (negative type photographic method) carried out using a so-called usual silver salt photographic film that has been known for a long time, for example, the method described in Patent Document 3, that is, A silver salt-containing layer containing a silver salt provided on a support is exposed and developed to form a metallic silver portion and a light transmitting portion, and the metallic silver portion is physically developed and / or plated. It is a method of forming a conductive metal part by carrying conductive metal particles on the metal silver part by processing.

Another method of silver salt photographic development (positive type photographic process) is a method described in Patent Document 4, that is, a silver salt photographic development method, in which silver halide is dissolved with a soluble silver complex salt forming agent. In this method, a soluble silver complex salt is formed and simultaneously reduced with a reducing agent (developing agent) such as hydroquinone to deposit metallic silver having an arbitrary fine line pattern on the development nucleus.
In Japanese Examined Patent Publication No. 42-23745, a silver halide emulsion layer and a silver halide solvent (a silver complex salt forming material) are applied, and a conductive film composed of physically developed silver by a silver complex diffusion transfer development method (DTR development method). A technique for forming a conductive layer is described. However, as described above, in order to satisfy simultaneously the translucency of 50% or more of the total light transmittance and the conductivity of 10 ohm / □ or less, which is required for the recent electromagnetic shielding material, the above-mentioned patent publication It was not possible to achieve only with the technique described in.

Hereinafter, since the description overlaps in the positive type photographic method-plating method and the negative type photographic method-plating method, a fine line pattern is formed with developed silver generated by the photographic method mainly using the positive type photo-plating method described above. A method will be described. In the present invention, the negative photographic method-plating method can be basically carried out according to the positive photographic method-plating method.
That is, the present invention can be applied to either a positive photographic process or a negative photographic process.

(Positive photographic process-plating method: physical development nucleus)
It is preferable that a physical development nucleus layer is provided in advance on the support substrate S (see FIG. 2) on which a fine silver mesh pattern of developed silver is formed. Although it does not specifically limit as the support base material S, The plastic film similar to the transparent base material 12 can be used.
As the physical development nuclei, fine particles (having a particle size of about 1 to several tens of nm) made of heavy metals or sulfides thereof are used. Examples thereof include colloids such as gold and silver, metal sulfides obtained by mixing water-soluble salts such as palladium and zinc and sulfides, and the like. The fine particle layer of these physical development nuclei can be provided on the transparent substrate by a vacuum deposition method, a cathode sputtering method, a coating method or the like. From the viewpoint of production efficiency, a coating method is preferably used. The content of physical development nuclei in the physical development nuclei layer is suitably about 0.1 to 10 mg per square meter in solid content.

  The support substrate S can be provided with an adhesive layer of a polymer latex layer such as vinylidene chloride or polyurethane, and an intermediate layer made of a hydrophilic binder such as gelatin is provided between the adhesive layer and the physical development nucleus layer. You can also.

  The physical development nucleus layer preferably contains a hydrophilic binder. The amount of the hydrophilic binder is preferably about 10 to 300% by mass with respect to the physical development nucleus. As the hydrophilic binder, gelatin, gum arabic, cellulose, albumin, casein, sodium alginate, various starches, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, a copolymer of acrylamide and vinyl imidazole, and the like can be used. The physical development nucleus layer may also contain a hydrophilic binder crosslinking agent.

  The physical development nucleus layer and the intermediate layer can be applied by an application method such as dip coating, slide coating, curtain coating, bar coating, air knife coating, roll coating, gravure coating, spray coating, and the like. In the present invention, the physical development nucleus layer is preferably provided as a continuous and uniform layer by the above-described coating method.

  In the present invention, the supply of silver halide for precipitating silver metal on the physical development nucleus layer is performed by a method in which the physical development nucleus layer and the silver halide emulsion layer are integrally provided in this order on the support substrate S, or separately. There is a method of supplying a soluble silver complex salt from a silver halide emulsion layer provided on a substrate such as paper or plastic resin film. From the viewpoint of cost and production efficiency, the former physical development nucleus layer and the silver halide emulsion layer are preferably provided integrally.

(Negative photographic process-plating method: silver halide emulsion)
In the present invention, the silver halide emulsion can be produced according to a general method for producing a silver halide emulsion of a silver halide photographic light-sensitive material. The silver halide emulsion is usually prepared by mixing and ripening an aqueous silver nitrate solution, an aqueous halogen solution of sodium chloride or sodium bromide in the presence of gelatin.
The silver halide composition of the silver halide emulsion layer used in the present invention preferably contains 80 mol% or more of silver chloride, and more preferably 90 mol% or more is silver chloride. The conductivity of the physically developed silver formed by increasing the silver chloride content is improved.

  The silver halide emulsion layer used in the present invention is sensitive to various light sources. As one method for producing an electromagnetic wave shielding material, for example, formation of physically developed silver having a fine line pattern such as a mesh shape can be mentioned. In this case, the silver halide emulsion layer is exposed in the form of a fine line pattern. As an exposure method, a method in which a transparent original having a fine line pattern and the silver halide emulsion layer are in close contact with each other and exposed with ultraviolet light, or various laser beams are used. Scanning exposure method. The former contact exposure using ultraviolet light is possible even if the silver halide has relatively low photosensitivity, but in the case of scanning exposure using laser light, relatively high photosensitivity is required. Therefore, when the latter exposure method is used, the silver halide may be subjected to chemical sensitization or spectral sensitization with a sensitizing dye in order to increase the sensitivity of the silver halide. Chemical sensitization includes metal sensitization using a gold compound or silver compound, sulfur sensitization using a sulfur compound, or a combination thereof. Gold-sulfur sensitization using a gold compound and a sulfur compound in combination is preferable. In the exposure method using the laser beam described above, a laser beam having an oscillation wavelength of 450 nm or less, for example, a blue semiconductor laser (also referred to as a violet laser diode) having an oscillation wavelength of 400 to 430 nm is used. It can be handled even under a yellow fluorescent lamp.

  In the present invention, an arbitrary position on the support substrate S on which the physical development nucleus layer is provided, for example, an adhesive layer, an intermediate layer, a physical development nucleus layer or a silver halide emulsion layer, or a backing layer provided with the support interposed therebetween. May contain a dye or pigment for preventing halation or irradiation.

(Positive photographic process-plating method: exposure and development)
When producing an electromagnetic shielding material using a photosensitive material in which a silver halide emulsion layer is coated directly on the physical development nucleus layer or via an intermediate layer, an arbitrary fine line pattern such as a mesh pattern is used. The light-sensitive original and the photosensitive material are in close contact with each other and exposed, or a digital image of an arbitrary fine line pattern is exposed to the photosensitive material by scanning with a laser beam output machine, and then in the presence of a soluble silver complex salt forming agent and a reducing agent. In an alkaline solution, silver complex diffusion transfer development (DTR development) occurs, the silver halide in the unexposed area is dissolved to form a silver complex salt, and reduced on the physical development nucleus to deposit metallic silver. A physically developed silver thin film having a fine line pattern can be obtained. The exposed portion is chemically developed in the silver halide emulsion layer to become blackened silver. After development, the silver halide emulsion layer and intermediate layer, or the protective layer provided as necessary, are washed away with water, and a physically developed silver thin film having a fine line pattern is exposed on the surface.

  After DTR development, the silver halide emulsion layer or the like provided on the physical development nucleus layer may be removed by washing with water or transferring and peeling to a release paper or the like. There are two methods for removing the water washing: a method of removing hot water using a scrubbing roller or the like while jetting it with a nozzle or the like, and a method of removing hot water by jetting with a nozzle or the like.

  On the other hand, when the soluble silver complex salt is supplied from a silver halide emulsion layer provided on a substrate different from the support substrate S coated with the physical development nucleus layer, the silver halide emulsion layer is exposed as described above. Then, the support substrate S coated with the physical development nucleus layer and another photosensitive material coated with the silver halide emulsion layer are mixed in an alkaline solution in the presence of a soluble silver complex salt forming agent and a reducing agent. After overlapping and adhering, and taking out from the alkaline solution, after several tens of seconds to several minutes, a physical development silver thin film having a fine line pattern deposited on the physical development nuclei is obtained by peeling off both.

  Next, a soluble silver complex salt forming agent, a reducing agent, and an alkali solution necessary for silver complex diffusion transfer development will be described. The soluble silver complex salt forming agent is a compound that dissolves silver halide to form a soluble silver complex salt, and the reducing agent is a compound that reduces this soluble silver complex salt to precipitate metallic silver on physical development nuclei. These actions are performed in an alkaline solution.

  Examples of the soluble silver complex forming agent used in the present invention include sodium thiosulfate, thiosulfate such as ammonium thiosulfate, thiocyanate such as sodium thiocyanate and ammonium thiocyanate, alkanolamine, sodium sulfite, and potassium bisulfite. Sulfites such as T. H. Examples include the compounds described in 474-475 (1977) of James The Theory of the Photographic Process 4th edition.

  As the reducing agent, a developing agent known in the field of photographic development can be used. For example, hydroquinone, catechol, pyrogallol, methylhydroquinone, polyhydroxybenzenes such as chlorohydroquinone, 1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-3-pyrazolidone, 1-phenyl-4-methyl- Examples include 3-pyrazolidones such as 4-hydroxymethyl-3-pyrazolidone, paramethylaminophenol, paraaminophenol, parahydroxyphenylglycine, paraphenylenediamine, and the like.

  The above-described soluble silver complex salt forming agent and reducing agent may be applied to the supporting substrate S together with the physical development nucleus layer, may be added to the silver halide emulsion layer, or in the alkaline solution. It may be contained, and may be further contained at a plurality of positions, but is preferably contained at least in the alkaline liquid.

  The content of the soluble silver complex salt forming agent in the alkaline solution is suitably used in the range of 0.1 to 5 mol per liter of the developer, and the reducing agent is 0.05 to 1 per liter of the developer. It is suitable to use in the molar range.

  The pH of the alkaline solution is preferably 10 or more, and more preferably in the range of 11-14. Application of the alkaline solution for silver complex diffusion transfer development may be an immersion method or a coating method. The immersion method is, for example, transporting while immersing a transparent substrate provided with a physical development nucleus layer and a silver halide emulsion layer in an alkaline solution stored in a large amount in a tank. For example, about 40 to 120 ml of an alkaline solution per square meter is applied on the silver halide emulsion layer.

(Dimension of fine line pattern)
As described above, there are fine line patterns in which, for example, fine lines having a line width of about 10 to 100 μm are provided in a grid pattern in the vertical and horizontal directions. If the narrow line width is reduced and the interval between the gratings is increased, the translucency increases. However, the conductivity decreases, and conversely, if the fine line width is increased to reduce the lattice spacing, the translucency is decreased and the conductivity is increased. The physically developed silver having an arbitrary fine line pattern formed on the support substrate S according to the present invention simultaneously satisfies the light transmittance of 50% or more of the total light transmittance and the conductivity of 10 ohm / □ or less of the surface resistivity. It is difficult to make it. Specifically, this physically developed silver has a surface resistivity of 50 ohms / square or less, preferably 20 ohms / square or less, but has a fine line width of 50 μm or less, for example, a pattern with a fine line width of 20 μm. When the light transmittance is 50% or more, the surface resistivity becomes several hundred ohms / square to 1000 ohms / square or more. However, since this physical development silver itself has a conductive silver image with a solid silver image formed, the fine line pattern is reduced to 0 by applying plating (plating) with a metal such as copper or nickel, particularly electrolytic plating. When the thickness is 5 to 15 μm and the line width is 10 to 50 μm, the surface resistivity is 10 ohms / square or less even for a translucent thin line pattern having a total light transmittance of 50% or more, preferably 60% or more. Preferably, the conductivity of 7 ohm / square or less can be maintained.
In order to improve the total light transmittance of the metal mesh, it is necessary to sufficiently increase the area of the light transmission portion between the fine lines with respect to the area of the region where the fine lines are provided. For this reason, it is preferable that the space | interval of a thin wire | line is 100-900 micrometers, More preferably, it is 150-700 micrometers.

(Plating of fine line pattern on metallic silver)
The thickness of the metal-plated fine line pattern can be arbitrarily changed according to desired characteristics, but is in the range of 0.5 to 15 μm, preferably 2 to 12 μm.
The electromagnetic wave shielding material of the present invention has an excellent total light transmittance of 50% or more and a surface resistivity of 10 ohm / □ or less when the fine line pattern has a thickness of 0.5 to 15 μm and a line width of 1 to 40 μm. It has light-transmitting performance and conductive performance, and can exert a shielding effect of 30 dB or more over a wide frequency band such as 30 MHz to 1,000 MHz.

  The electroconductive metal can be plated on the developed silver mesh pattern 17 by any of an electroless plating method, an electrolytic plating method, or a plating method in which both are combined, but an electromagnetic wave shielding layer is formed on the support substrate S. In view of the above, the roll-shaped long web provided with the physical development nucleus layer and the silver halide emulsion layer on the support substrate S can be subjected to at least a series of processes such as exposure of fine line pattern, development process and plating process. Therefore, a method in which electrolytic plating or a combination of electroless plating is preferable.

In the present invention, the method of plating the metals 18a and 18b on the developed silver mesh pattern 17 is as follows.
A developed silver mesh pattern 17 generated by a photographic method is formed on one side of the support substrate S, and copper (Cu) and / or nickel (Ni) is plated on the developed silver layer 17.
In the present invention, the metal plating method can be performed by a known method. For example, the electrolytic plating method uses a conventionally known method such as copper, nickel, silver, gold, solder, or a multilayer or composite system of copper / nickel. For these, reference can be made to documents such as “Surface Treatment Technology Overview; Technical Data Center Co., Ltd., December 21, 1987, first edition, pages 281 to 422”.
It is preferable to use copper and / or nickel for reasons such as easy plating, excellent electrical conductivity, plating on a thick film, and low cost. In particular, the first plating layer 18a laminated on the developed silver layer 17 is a copper plating layer formed by electroless copper plating and / or electrolytic copper plating, and the second plating laminated on the first plating layer 18a. A combination in which the layer 18b is a nickel plating layer is preferable. It is preferable to apply a blackening process to the surface of the second plating layer 18b. In this embodiment, since the electromagnetic wave shielding material 14 is attached to one side of the transparent substrate 12 having the antireflection layer 11 by transfer on the metal plating layer 18b side, the blackened plating layer 18b is on the visual side. Can be arranged.

(Electroless copper plating)
The electroless copper plating solution preferably has a metal copper (Cu) concentration of 0.5 to 10 g / liter, more preferably 2 to 3 g / liter.
As temperature of a plating process liquid, 30-80 degreeC is preferable, More preferably, it is 40-50 degreeC. If the temperature of the plating solution is lower than 30 ° C., the copper deposition rate is slow, and if it is 80 ° C. or higher, the energy cost increases, which is not preferable.
The plating thickness is preferably 0.01 to 1 μm, and more preferably 0.05 to 0.2 μm. Further, the electroless copper plating solution may be any solution as long as it is a known plating solution.

(Electrolytic copper plating)
In the case of electrolytic copper plating, any plating solution such as copper sulfate, copper cyanide, and copper pyrophosphate may be used, but copper sulfate is preferable from the viewpoint of cost. In these electrolytic copper plating solutions, the concentration of copper (Cu) may be set to an appropriate concentration.
When using a copper sulfate plating bath, the sulfuric acid concentration is preferably 20 to 400 g / liter, more preferably 70 to 300 g / liter. If the sulfuric acid concentration is lower than 20 g / liter, the plating solution becomes unstable, and if it is higher than 300 g / liter, abnormalities occur in the plating particles.
The plating temperature is preferably 10 to 60 ° C, more preferably 20 to 40 ° C. If the temperature of the plating solution is lower than 10 ° C., the plating time will be longer and the cost will be increased.
The current density of electrolytic plating is preferably 0.05 to 20 A / cm ² , more preferably 0.5 to 8 A / cm ² . When the current density of electrolytic plating is lower than 0.05 A / cm ² , the plating time becomes longer and the cost increases. Moreover, if the current density of electrolytic plating is higher than 20 A / cm ² , the appearance of the plating film is deteriorated, which is not preferable.

(Electrolytic nickel plating)
When performing electrolytic nickel plating, any plating bath such as watt bath (nickel sulfate, nickel chloride, boric acid), nickel sulfamate bath (nickel sulfamate, nickel chloride, boric acid), etc. But you can.

(Blackening treatment)
The outermost surface of the metal plating layer 18b is preferably blackened to prevent reflection of light due to the gloss of the plated metal. As a method of blackening treatment of the surface of the nickel plating layer 18b, there is no particular limitation on the type of blackening treatment film and the composition of the blackening treatment liquid to be used. As a preferable example, when black nickel is used, the blackening treatment is performed. The concentration of nickel sulfate in the liquid is preferably 10 to 50 g / liter, more preferably 20 to 40 g / liter. When the concentration of nickel sulfate is lower than 10 g / liter, plating deposition is delayed and the cost is increased, and when it is higher than 50 g / liter, the finished color of the blackening treatment is not stable.

(Alkali treatment of substrate)
After the step of producing the developed silver mesh pattern 17 generated by the photographic method on the support substrate S, conductive metal plating layers 18a and 18b are laminated on the developed silver mesh pattern 17 to form a metal mesh pattern. In order to make the electromagnetic wave shielding material 14 easy to peel from the support base material S in the process of transferring the electromagnetic wave shielding material 14 to one side of the transparent base material 12, The formed support substrate S is subjected to alkali treatment.

  The alkali treatment is performed by immersing the support substrate S on which the electromagnetic wave shielding material 14 is formed in a strong alkaline solution (sodium hydroxide aqueous solution, potassium hydroxide aqueous solution) having a pH of 12 to 13. By this alkali treatment, the adhesion between the electromagnetic wave shielding material 14 and the support base material S is reduced, and the electromagnetic wave shielding material 14 becomes easy to peel from the support base material S. After the support substrate S on which the electromagnetic wave shielding material 14 is formed is alkali-treated, the excess chemical solution adhering to the electromagnetic wave shielding material 14 and the supporting substrate S is sufficiently washed and removed by neutralization treatment, water washing or the like. Then, drain and dry.

  The electromagnetic shielding material 14 obtained by the above method has a total light transmittance of 50% when the fine line pattern has a thickness of 0.5 to 15 μm and a line width of 10 to 50 μm, and the interval between the fine lines is 100 to 900 μm. As described above, the surface resistivity is 10 ohms / square or less and has excellent light transmission performance and conductive performance, and a shielding effect of 30 dB or more can be exhibited over a wide frequency band such as 30 MHz to 1,000 MHz.

  In the case of the above-described DTR-plating method, physical development nuclei remain on the entire surface of the support substrate S. Conventionally, when a physical development silver layer is formed on a transparent substrate, there is a theory that the DTR-plating method is insufficient in terms of transparency because of the remaining physical development nuclei. Since 14 is transferred to another transparent substrate 12, the support substrate S is not included in the layer configuration of the optical filter 10. For this reason, sufficient transparency can be obtained in the optical filter 10 of the present invention.

(Optical filter manufacturing method)
In this invention, it produces | generates on the support base material S by the photographic manufacturing method using either of two different silver salt photographic development methods (positive type photographic manufacturing method-plating method, negative type photographic manufacturing method-plating method). An electromagnetic wave shielding material 14 formed by forming a thin line pattern thin film 17 made of developed silver and laminating metal layers 18a and 18b on the thin line pattern 17 by plating is used. The electromagnetic wave shielding material 14 is formed by transferring the electromagnetic wave shielding material 14 formed on the support base material S by the photographic manufacturing method-plating method to one side of the transparent base material 12 constituting the optical filter 10.

Although the manufacturing method of the optical filter 10 shown in FIG. 1 is not specifically limited, For example, the method shown below can be used. In addition, in order to protect an adhesive layer during a manufacturing process or after a process, you may laminate | stack release paper arbitrarily.
(1) As shown in FIG. 2, a developed silver mesh pattern 17 formed on a supporting substrate S and produced by a photographic method and plated layers 18a and 18b laminated thereon, preferably Prepares an electromagnetic wave shielding material 14 having a metal mesh pattern comprising a copper plating layer 18a (by electroless copper plating and / or electrolytic copper plating) and / or a nickel plating layer 18b.
In addition, the electromagnetic wave shielding material 14 formed on the support base material S is immersed in a strong alkaline solution having a pH of 11 to 13 to reduce the adhesion between the electromagnetic wave shielding material 14 and the support base material S, and the electromagnetic wave shielding material 14. It is preferable to make it easy to peel from the support substrate S.
(2) The antireflection layer 11 is provided on one side of the transparent substrate 12 to produce a laminate (AR film) A.
(3) The pressure-sensitive adhesive layer 13 is provided on the surface of the laminate A opposite to the surface on which the antireflection layer 11 is provided. On the pressure-sensitive adhesive layer 13, an electromagnetic wave shielding material 14 is bonded and pressure bonded as shown in FIG. 3A, and then the support base S is peeled off as shown in FIG. Is transferred onto the pressure-sensitive adhesive layer 13 of the laminate A, and the electromagnetic wave shielding layer of the optical filter 10 is formed by the electromagnetic wave shielding material 14.
In FIG. 3, the illustration of the antireflection layer 11 is omitted for simplicity, but in this embodiment, the antireflection layer 11 is provided on the lower surface of the transparent substrate 12 in FIG. 3.
(4) The pressure-sensitive adhesive layer 15 is embedded and smoothed in the depression of the transferred metal mesh pattern, which is the electromagnetic wave shielding material 14 formed on the pressure-sensitive adhesive layer 13 of the laminate A.
(5) The pressure-sensitive adhesive layer 16 is further laminated on the pressure-sensitive adhesive layer 15 to obtain the optical filter 10 of this embodiment (see FIG. 1).

  When transferring the electromagnetic shielding material 14 to the laminate A, a pressure-sensitive adhesive layer 13 is provided on one side of the transparent substrate 12 as a transfer destination adhesive layer. As the pressure-sensitive adhesive, a pressure-sensitive adhesive having an appropriate adhesive force, or a curable adhesive that is cured by light, ionizing radiation, heat, or the like can be used. In the present invention, an acrylic-based thermosetting adhesive is particularly preferable because it is cured after bonding and the shape is stabilized.

The optical filter 10 of this embodiment can be used by being attached to the front panel P of the display or the like with the pressure-sensitive adhesive layer 16 provided on the innermost side.
According to the method for producing an electromagnetic shielding material of the present invention, an electromagnetic shielding material comprising a metal mesh pattern is produced by an inexpensive production method based on resource saving, and the electromagnetic shielding material is easily transferred to another transparent substrate. Thus, it is possible to provide an optical filter that can be reduced in weight by reducing the thickness of the entire optical filter, has high electromagnetic shielding properties, and is excellent in translucency and capable of obtaining a clear image. it can.

When the optical filter of the present invention is used as an optical filter for a display, a metal mesh pattern 25 is produced on a transparent substrate 24 in the prior art (see FIG. 4) and is directly bonded to a constituent layer of the optical filter. As compared with, since one transparent base film used for producing a metal mesh pattern can be omitted, the translucency of visible light can be improved.
In the optical filter 20 shown in FIG. 4, reference numeral 21 denotes an antireflection layer, 22 denotes a transparent base material laminated with the antireflection layer, 23 denotes an adhesive layer, 24 denotes a support substrate of a metal mesh pattern, and 25 denotes a metal. Mesh patterns 26 and 27 are adhesive layers.

  According to the present invention, the copper plating layer 18a is laminated by electroless plating and / or electrolytic plating in contact with the developed silver mesh pattern 17 formed by the photographic method, which is formed on the support substrate S. Therefore, due to the phenomenon that metallic silver diffuses and migrates from the developed silver layer 17 on the support base material S into the copper plating layer 18a, the adhesion between the electromagnetic wave shield material 14 and the support base material S decreases, and the electromagnetic wave shield material 14 It floats from the support substrate S, and the electromagnetic shielding material 14 is easily peeled from the support substrate S.

Further, the present invention reduces the adhesion between the electromagnetic shielding material 14 and the supporting substrate S by immersing the electromagnetic shielding material 14 formed on the supporting substrate S in a strong alkaline solution having a pH of 11 to 13. Therefore, the electromagnetic wave shielding material 14 is easily peeled from the support base material S.
For this reason, in the present invention, in the step of peeling the electromagnetic wave shielding material 14 from the support base material S and transferring it to the transparent base material 12, the electromagnetic wave shielding material 14 formed on the support base material S is replaced with the optical filter 10. After the pressure-sensitive adhesive layer 13 is pressure-bonded to the transparent base material 12 included in the constituent layers, the work of peeling off and transferring the electromagnetic wave shielding material 14 whose adhesion with the supporting base material S is reduced can be performed smoothly.

  INDUSTRIAL APPLICATION This invention can be utilized as an optical filter using the electromagnetic wave shielding material used for various displays, such as CRT, PDP (plasma display), a liquid crystal, and EL.

(A) is typical sectional drawing which shows an example of the optical filter for displays of this invention, (b) is the elements on larger scale which show the layer structure. It is typical sectional drawing which shows an example of the laminated body in which the electromagnetic wave shielding material was provided on the support base material. (A) is typical sectional drawing explaining a mode that the electromagnetic wave shielding material provided on the support base material is transcribe | transferred on a transparent base material, (b) is a mode that a support base material is peeled from an electromagnetic wave shielding material. It is a typical sectional view explaining. It is typical sectional drawing which shows an example of the optical filter for displays by the conventional method.

Explanation of symbols

P ... front panel, S ... support substrate, 10 ... optical filter for display (optical filter), 11 ... antireflection layer, 12 ... transparent substrate (ultraviolet absorption layer), 13 ... adhesive layer (light absorber dispersion layer) ), 14 ... Electromagnetic shielding material, 15 ... Adhesive layer, 16 ... Adhesive layer (near infrared absorbing layer), 17 ... Developed silver mesh pattern, 18a ... First metal plating layer (copper plating layer), 18b ... First 2 metal plating layers (nickel plating layers).

Claims (8)

  An optical filter for a display in which an electromagnetic wave shielding material is disposed, and an electromagnetic wave shielding material comprising a conductive metal mesh pattern and a metal plating layer laminated thereon is provided on one side of a transparent substrate constituting the optical filter. An optical filter for a display, characterized in that the optical filter is attached.   2. The display optical filter according to claim 1, wherein the conductive metal mesh pattern is a developed silver mesh pattern generated by a photographic method.   3. The display optical filter according to claim 2, wherein the metal plating layer includes an electroless copper plating layer and / or an electrolytic copper plating layer laminated on and in contact with the developed silver mesh pattern.   4. The optical filter for display according to claim 2, wherein the developed silver mesh pattern is generated by a positive photographic process or a negative photographic process.   5. The optical filter according to claim 1, further comprising at least one of a near-infrared absorbing layer, an ultraviolet absorbing layer, a neon light absorbing layer, a light absorbing material dispersion layer, and an antireflection layer. The optical filter for display according to any one of the above.   A method of manufacturing an optical filter for a display in which an electromagnetic wave shielding material is disposed, wherein a mesh pattern generating step of generating a developed silver mesh pattern on a support substrate by a photographic method, and a conductive on the developed silver mesh pattern A plating step for forming an electromagnetic wave shielding material made of a metal mesh with a conductive metal plating layer, and the electromagnetic wave shielding material is attached to one side of a transparent substrate constituting an optical filter on the metal plating layer side by transfer. And a transfer step. A method for producing an optical filter for display.   Between the plating step and the transfer step, the electromagnetic shielding material formed on the supporting substrate is immersed in a strong alkaline solution having a pH of 11 to 13, whereby the adhesion between the electromagnetic shielding material and the supporting substrate is increased. The method for producing an optical filter for display according to claim 6, further comprising an alkali treatment step for lowering the pH.   The method for producing an optical filter for display according to claim 6 or 7, wherein the developed silver mesh pattern is generated by a positive photographic process or a negative photographic process.

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