WO2007083849A1

WO2007083849A1 - Optically transparent electromagnetic shielding film for optical filter of plasma display, and optical filter

Info

Publication number: WO2007083849A1
Application number: PCT/JP2007/051341
Authority: WO
Inventors: Kentaro Okazaki
Original assignee: Fujifilm Corporation
Priority date: 2006-01-23
Filing date: 2007-01-23
Publication date: 2007-07-26
Also published as: JP2007200922A

Abstract

An optically transparent electromagnetic shielding film, which comprises a transparent support, a conductive metal part, and a visible light transmitting part, wherein the conductive metal part is in the shape of a mesh made of fine wires having a wire width of from 1 to 40 µm, the conductive metal part has a thickness of from 1 to 6 µm, and a haze value of the optically transparent electromagnetic shielding film is from 0.1 to 10%, and an optical filter which comprises the optically transparent electromagnetic shielding film

Description

DESCRIPTION

OPTICALLY TRANSPARENT ELECTROMAGNETIC SHIELDING FILM FOR OPTICAL FILTER OF PLASMA DISPLAY,

AND OPTICAL FILTER

Technical Field

The present invention relates to an optically transparent conductive film. Particularly, it relates to an electromagnetic shielding film that shields electromagnetic wave generated from a front surface of displays such as CRT (cathode ray tube), PDP (plasma display panel), liquid crystal, EL (electroluminescence), and FED (field emission display), and has optically transparent property, and an optical filter laminate using the same.

Background Art

A plasma display panel (hereinafter referred to as "PDP") is in widespread use as a thin-model image display device with a large screen. PDP is provided with an electromagnetic shielding means on a front surface of a panel in order to prevent leakage of electromagnetic wave generated from a panel body into the outside of the display. The electromagnetic shielding means uses, for example, a surface glass having a metal thin film formed thereon, and an electromagnetic shielding film provided with an electromagnetic shielding coating that covers a panel front surface with mesh-like patterns of a metal fine wire. The latter is becoming the mainstream in the point that it is excellent in compatibility between light transmission and electromagnetic shielding ability. The electromagnetic shielding film is a functional film comprising a transparent film having formed thereon metal fine wires in a lattice pattern (mesh pattern).

Various materials and methods such as a shielding material comprising mesh conductive fibers, a method of printing an electroless plating catalyst as a lattice pattern by a printing method, and conducting electroless plating on the pattern, a method of pattern forming an electroless plating catalyst-containing photoresist in mesh pattern, and conducting electroless plating thereon, and a method of etching processing with a photolithography to form a mesh of metal thin film have hitherto been proposed as electromagnetic shielding materials and methods that achieve both electromagnetic shielding property and transparency utilizing metal mesh having openings (sometimes called optically transparent part or light transmitting part). Above all, an etching work utilizing photolithography has mainly been employed. However, those methods have some problems in cumbersome and complicated production steps, production cost, uniformity of wire width at an intersection part of lattice patterns, compatibility between optical transparency and conductivity, and the like.

A method of forming a conductive metallic silver thin film pattern by a silver salt diffusion transfer method that precipitates silver on a physical development nucleus is disclosed in JP-B-42-23746 (the term "JP-B" as used herein means an "examined Japanese patent application") as a method of improving those problems. Further, JP-B-43-12862 discloses that a uniform silver thin film having no light transmission obtained by utilizing the similar silver salt diffusion transfer method has microwave attenuation function. Analytical Chemistry, 2000, Vol. 72, Section 645 and WO 01/51276 disclose a method of forming a conductive pattern having optical transparency imparted thereto by simply conducting exposure and development utilizing this principle to an instant black-and-white slide film.

However, including the above cases utilizing metallic silver inking to a photosensitive material by light irradiation for patterning and diffusion transfer, optically transparent electromagnetic shielding materials formed by patterning a visible light transmitting part and a conductive metal part by the conventional methods remain the problem that image quality is damaged by diffused reflection of a conductive metal part, reflection of outside light due to surface scattering of a visible light transmitting part, and light scattering from a display luminous body. To improve this problem, countermeasures have been made to, for example, fill up with a specific resin so as to be height of the conductive metal part and the visible light transmitting part constant (so as to reduce surface asperity). In general, optical filter laminates having light scattering preventive function imparted to an adhesive of other optical filter material laminated on a conductive metal part of an electromagnetic shielding material are disclosed.

On the other hand, it is necessary to provide an earth on the conductive metal part in order to efficiently shield electromagnetic wave. In general, it is necessary to connect to the earth by contacting with a metal piece or the like in several mm to several cm width so as to be electrically conduct around an optically transparent conductive film. For this, the improvement in light scattering must avoid earth region, and has involved large step loads of position matching, molding of an optical filter material to be laminated, and the like.

Disclosure of the Invention

The present invention has been made in view of the above circumstances, and one object of the invention is to provide an electromagnetic shielding film that satisfies both light transmitting property and electromagnetic shielding ability, shows less surface light scattering, and can be produced at low cost.

Another object of the invention is to provide an optical filter for a plasma display, having light transmitting property and electromagnetic shielding ability, and further at least one of optical functionalities in combination by combining an element of laminating the electromagnetic shielding film and an optically functional layer.

Still another object of the invention is to provide a plasma display panel having excellent image display property, comprising the optical filter mounted thereon.

The present inventors analyzed the phenomenon that image quality is damaged by light scattering reflection of a conductive metal part and surface scattering of a visible light transmitting part (optically transparent part), searched surface smoothing means on the basis of recognition that it is very important to substantially solve the problem that the surface smoothing is damaged by irregularity of mesh-like patterns, and could reached the following invention that can reduce mesh surface unevenness. That is, the invention relates to optically transparent electromagnetic shielding films of the following <1> to <7>, and optical filters using the same, of the following <8> to <13>.

<1> An optically transparent electromagnetic shielding film, which comprises: a transparent support; a conductive metal part; and a visible light transmitting part, wherein the conductive metal part is in the shape of a mesh made of fine wires having a wire width of from 1 to 40 μm, the conductive metal part has a thickness of from 1 to 6 μm, and a haze value of the optically transparent electromagnetic shielding film is from 0.1 to 10%.

<2> The optically transparent electromagnetic shielding film as described above in <1>, wherein the conductive metal part and the visible light transmitting part are formed by subjecting pattern exposure and development treatment to a silver salt photosensitive material which comprises an emulsion layer containing a silver halide.

<3> The optically transparent electromagnetic shielding film as described above in <2>, wherein the silver salt photosensitive material comprises at least one hydrophilic colloid layer, and the silver salt photosensitive material is roll-shaped.

<4> The optically transparent electromagnetic shielding film as described above in <3>, wherein the hydrophilic colloid layer has a thickness of from 0.5 to 2 μm.

<5> The optically transparent electromagnetic shielding film as described above in any of <1> to< 4>, wherein 20% or more of a surface area of the conductive metal part is black.

<6> The optically transparent electromagnetic shielding film as described above in any of <2> to <5>, wherein the conductive metal part comprises a developed silver formed by the development treatment and a metal deposit added on the developed silver by electroless plating treatment or electrolytic plating treatment.

<7> The optically transparent electromagnetic shielding film as described above in any of <2> to <6>, wherein, while the silver salt photosensitive material is transported, the pattern exposure is conducted through a photomask and the development treatment is conducted.

<8> An optical filter comprising an optically transparent electromagnetic shielding film as described above in any of <1> to <7>.

<9> The optical filter as described above in <8>, which further comprises a functional transparent layer having at least one function selected from the group consisting of infrared shielding property, hard coating property, antireflective property, glare-proof property, antistatic property, ultraviolet shielding property, gas barrier property and display panel breakage prevention property.

<10> The optical filter as described above in <8> or <9>, which further comprises an adhesive layer.

<11> The optical filter as described above in any of <8> to <10>, which further comprises a peelable protective film.

<12> The optical filter as described above in any of <8> to <11>, wherein the conductive metal part and the visible light transmitting part of the optically transparent electromagnetic shielding film are arranged outermost.

<13> The optical filter as described above in any of <9> to <12>, which comprises the optically transparent electromagnetic shielding film, an infrared absorption filter having the infrared shielding property, an antireflective film having the antireflective property and a transparent substrate, wherein the optically transparent electromagnetic shielding film is arranged at one side of the transparent substrate and the infrared absorption filter and the antireflective film are arranged at the other side of the transparent substrate. Brief Description of the Drawing

Fig. 1 is a view showing a frame format of one example of the electrolytic plating bath suitably used in the invention, wherein 10 denotes Electrolytic plating apparatus; 11 denotes Electrolytic cell; 12a and 12b denote Feed rollers; 13 denotes Anode plate; 14 denotes Guide roller; 16 denotes film; and 17 denotes Liquid-cutting roller.

Best Mode for Carrying Out the Invention

The optically transparent electromagnetic shielding film of the invention and the optical filter having the same mounted thereon are described in detail below.

In the present specification, the expression "from A to B" is used to mean that the numerical values A and B are included as the lower limit and the upper limit. Further, the term "mesh" means "mesh pattern comprising plural fine wires or net comprising plural fine wires" according to the convention by one skilled in the art.

The characteristics of the optically transparent electromagnetic shielding film of the invention are that first, a silver salt photosensitive material is used as means to realize smooth film surface by reducing thickness difference between the conductive metal part and the visible light transmitting part, and by this, thickness corresponding to at least a hydrophilic colloid layer is secured even in the visible light transmitting part, thereby reducing the thickness difference to the conductive metal part; and second, the shape (wire width and opening area) of mesh-like pattern is adjusted to control the thickness of the metal fine wire of the conductive metal part to a range that surface unevenness does not adversely affect surface reflection, and consequently a range that haze does not increase.

To fulfill the above characteristics of the invention and to secure sufficient conductivity, the metal fine wire is preferable that a metal is added on a developed silver by electroless plating or electrolytic plating. Further, to suppress haze, it is preferable that thickness of the hydrophilic colloid layer is from 0.5 to 2 μm, and it is preferable that silver halide/hydrophilic colloid ratio of the photosensitive material is designed so as to satisfy this range. The term "thickness of hydrophilic colloid layer" used herein means a thickness of the light transmitting part, that is, a thickness of an opening surrounded in a mesh-like structure, of the conductive metal part. In the invention, the haze value is from 0.1 to 10%, and preferably from 0.1 to 6%. The practical limit of haze value reduction is 0.1%, but wherever feasible, the smaller haze value is further preferable.

In addition to the above, blacking the surface of conductive metal part suppresses surface light scattering to thereby reduce haze. Especially, remarkable haze reduction effect is exhibited by blacking 20% or more of the surface.

The optically transparent electromagnetic shielding film of the invention can further suppress light scattering by providing an adhesive layer on the film surface. Further, when a functional layer having at least one of infrared shielding property, bar code property, antireflective property, antistatic property, glare-proof property, anti-stain property, ultraviolet cutting property, gas barrier property, display panel damage preventive property and the like is adhered to the film through the adhesive layer, further excellent surface light scattering suppression and haze reduction effects are exhibited.

Therefore, the optical filter comprising a laminate of the above functional layer, adhesive layer and optically transparent electromagnetic shielding layer is an excellent embodiment of the invention.

On the other hand, the above functional layer can exhibit the desired effect of the invention even in an optical filter comprising a transparent support, an optically transparent electromagnetic shielding layer and the functional layer adhered on a surface of the transparent support opposite the optically transparent electromagnetic shielding layer, so long as the optically transparent electromagnetic shielding layer is defined as the optically transparent electromagnetic shielding layer of the invention.

The elements constituting the invention are successively described in detail below.

Conductive film and its production method [Photosensitive material] Support

Plastic films, plastic plates and glass plates can be used as a support of the photosensitive material used in the production method of the invention.

Examples of raw materials of the plastic films and plastic plates that can be used include polyesters such as a polyethylene terephthalate (PET) and a polyethylene naphthalate; polyolefms such as a polyethylene (PE), a polypropylene (PP), a polystyrene and EVA; vinyl resins such as a polyvinyl chloride and a polyvinylidene chloride; a polyether ether ketone (PEEK), a polysulfone (PSF), a polyether sulfone (PES), a polycarbonate (PC), a polyamide, a polyimide, an acrylic resin, and a triacetyl cellulose (TAC).

In the invention, the plastic film is preferably a polyethylene terephthalate film and/or a triacetyl cellulose (TAC) from the points of transparency, heat resistance, ease of handling and cost.

Transparency is required in the electromagnetic shielding material for display. Therefore, the support desirably has high transparency. In this case, the plastic film or plastic plate has a total visible light transmission of preferably from 70 to 100%, further preferably from 85 to 100%, and particularly preferably from 90 to 100%. Further, the invention can use a support that is colored to an extent that does not impair the object of the invention, as the plastic film or plastic plate.

The plastic film and plastic plate in the invention can use as a monolayer, and can be used as a multilayer film comprising a combination of two or more layers.

When a glass plate is used as the support of the invention, its kind is not particularly limited. Where the glass plate is used in an electromagnetic shielding film for display, a reinforced glass having a reinforcing layer formed on the surface thereof is preferably used. The reinforced glass has high possibility to prevent breakage as compared with a non-reinforced glass. Further, a tempered glass obtained by air-cooling is preferable on safety in that if the glass breaks, its broken piece is small, and does not have a sharp edge. [Protective layer]

The photosensitive material used may be provided with a protective layer on an emulsion layer described hereinafter. The "protective layer" used herein means a layer comprising a binder such as gelatin or a high molecular polymer, and is formed on the emulsion layer having photosensitivity in order to exhibit an effect of improving scratch prevention or dynamic characteristics. The protective layer preferably is not provided from the point of plating. Where provided, the protective layer preferably has a small thickness, and the thickness is preferably 0.2 μm or less.

Coating method of the protective layer is not particularly limited, and the conventional coating method can appropriately be selected.

The photosensitive material used in the production method of the invention may contain the conventional dyes in the protective layer or the emulsion layer for the purpose of dyeing or the like. [Emulsion layer]

The photosensitive material used in the production method of the invention preferably has an emulsion layer containing a silver salt (silver salt-contained layer) as a light sensor. According to need, the emulsion layer in the invention can contain a dye, a binder, a solvent and the like in addition to a silver salt. Dye

The photosensitive material may contain a dye in at least the emulsion layer. The dye is contained in the emulsion layer as a filter dye or for various purposes such as irradiation prevention. The dye may include a solid disperse dye. Examples of the dye preferably used in the invention include dyes represented by the general formula (FA), the general formula (FAl), the general formula (FA2) and the general formula (FA3) described in JP-A-9- 179243. Specifically, the compounds Fl to F34 described in this publication are preferable. Further, (II-2) to (11-24) described in JP-A-7-152112, (III-5) to (TII-18) described in JP-A-7-152112, (IV-2) to (IV-7) described in JP-A-7-152112, and the like are also preferably used.

As dyes that can be used in the invention other than the above, examples of a dye in a solid fine particle dispersed state include cyanine dyes, pyrylium dyes and aminium dyes, described in JP-A-3-138640. Examples of a dye that does not decolorize when treating include cyanine dyes having a carboxyl group described in JP-A-9-96891, cyanine dyes not containing an acidic dye described in JP-A-8-245902, lake cyanine dyes described in JP-A-8-333519, cyanine dyes described in JP-A-1-266536, holopola cyanine dyes described in JP-A-3-136038, pyrylium dyes described in JP-A-62-299959, polymer cyanine dyes described in JP-A-7-253639, solid fine particle dispersion of oxonol dye described in JP-A-2-282244, light scattering particles described in JP-A-63-131135, Yb³⁺ compounds described in JP-A-9-5913 and ITO powders described in JP-A-7-113072. Additionally, dyes represented by the general formula (Fl) and general formula (F2) described in JP-A-9- 179243, specifically compounds F35 to F112 described therein, can also be used.

The above dyes can include a water-soluble dye. Examples of such a water-soluble dye include oxonol dyes, benzylidene dyes, merocyanine dyes, cyanine dyes and azo dyes. Above all, oxonol dyes, hemioxonol dyes and benzylidene dyes are useful in the invention. Specific examples of the water-soluble dye that can be used in the invention include compounds described in British Patents 584,609 and 1,177,429, JP-A-48-85130, 49-99620, 49-114420, 52-20822, 59-154439 and 59-208548, and US Patents 2,274,782, 2,533,4722,956,879, 3,148,187, 3,177,078, 3,247,127, 3,540,887, 3,575,704, 3,653,905 and 3,718,427.

The content of the dye in the emulsion layer is preferably from 0.01 to 10 mass%(in this specification, mass ration is equal to weight ratio), and more preferably from 0.1 to 5 mass%, based on the mass of the total solid content from the standpoints of the effect of irradiation prevention, sensitivity reduction due to increase of addition amount, and the like. Silver salt

The silver salt used in the invention includes inorganic silver salts such as a silver halide. It is preferable in the invention to use a silver halide having excellent characteristics as a light sensor.

The silver halide preferably used in the invention is described below.

It is preferable in the invention to use a silver halide in order to function the same as a light sensor. Technologies used in silver halide photographic films or photographic papers relating to a silver halide, printing plate making films, emulsion masks for photomask, and the like can be used in the invention.

A halogen element contained in the silver halide may be any of chlorine, bromine, iodine and fluorine, and may be combinations of those. For example, a silver halide mainly comprising AgCl, AgBr or AgI is preferably used, and a silver halide mainly comprising AgBr or AgCl is also preferably used. More preferable silver halide is silver chlorobromide, silver bromide, silver iodochlorobromide and silver iodobromide. Most preferable silver halide is silver chlorobromide and silver iodochlorobromide, containing 50 mol% or more of silver chloride.

The term "a silver halide mainly comprising AgBr (silver bromide)" used herein means a silver halide that molar fraction of bromide ion occupied in a silver halide composition is 50% or more. Silver halide particles mainly comprising the AgBr may contain iodide ion and chloride ion, in addition to bromide ion.

The silver halide is solid particles, and has an average particle diameter of preferably from 0.1 to 1,000 nm (1 μm), more preferably from 0.1 to 100 nm, and further preferably from 1 to 50 nm, in terms of a diameter of a corresponding sphere, from the standpoint of image quality of a pattern-like metallic silver layer formed after exposure and development treatment.

The term "diameter of a corresponding sphere of silver halide particles" means a diameter of a particle having a spherical shape and the same volume.

Shape of the silver halide particles is not particularly limited, and can be various shapes such as a spherical shape, a cubic shape, a flat plate shape (a hexagonal shape, a triangular shape, a guadrangular shape, and the like), an octahedron shape and a tetradecahedron shape. Of those, a cube and a tetradecahedron are preferable.

The silver halide particle may be that the inside and the surface layer comprise a uniform phase or comprise different phases. Further, a local layer having different halogen composition may be present in the inside or on the surface of the particle.

A silver halide emulsion that is a coating liquid for an emulsion layer used in the invention can be prepared using the methods described in, for example, P. Glafkides, Chimie et Physique Photographique (Paul Montel, 1967), G F. Dufin, Photographic Emulsion Chemistry (The Focal Press, 1966) and V. L. Zelikman, et al, Making and Coating Photographic Emulsion (The focal Press, 1964).

In other words, the preparation method of the silver halide emulsion may be any of an acidic process and a neutral process. Further, the method of reacting a water-soluble silver salt and a water-soluble silver halide may use any of a one-side mixing process, a simultaneous mixing process, and a combination thereof.

Further, the formation method of silver particles can use a method of forming particles under excess silver ions (so-called a reverse-mixing process). Further, a method of maintaining pAg in a liquid phase in which a silver halide is formed, constant, that is, a so-called controlled double jet method, can be used as one type of the simultaneous mixing process.

Further, it is preferable to form particles by using a silver halide solvent such as ammonia, thioether and tetrasubstituted thiourea. A tetrasubstituted thiourea compound is more preferable as such a method, and is described in JP-A-53-82408 and 55-77737. The preferable thiourea compound includes tetramethyl thiourea and thionic l,3-dimethyl-2-imidazolidine. The amount of the silver halide solvent added varies depending on the kind of a compound used, the desired particle size and halogen composition, but is preferably from 10^"5 to 10^"2 mol per mole of the silver halide.

In the controlled double jet method and the particle formation method using the silver halide solvent, it is easy to prepare a silver halide emulsion having a regular crystal shape and a narrow particle size distribution. Therefore, those methods are preferably used in the invention.

To make a particle size uniform, it is preferable to quickly grow silver in a range that does not exceed a critical degree of saturation using a method of changing addition rate of silver nitrate or an alkali halide according to particle growth rate as described in British Patent 1,535,016, and JP-B-48-36890 and 52-16364, or a method of changing concentration of an aqueous solution as described in US Patent 4,242,445 and JP-A-55-158124. The silver halide emulsion used in forming the emulsion layer of the invention is preferably a monodisperse emulsion, and has a variation coefficient represented by {(standard deviation of particle size)/(average particle size)}xlOO of preferably 20% or less, more preferably 15% or less, and most preferably 10% or less.

Plural kinds of silver halides having different particle size may be mixed with the silver halide emulsion used in the invention.

The silver halide emulsion used in the invention may contain metals belonging to Group VIII and Group VIIB. In particular, to achieve high contrast and low fogging, the silver halide emulsion preferably contains a rhodium compound, an iridium compound, a ruthenium compound, an iron compound, an osmium compound, a rhenium compound or the like. Those compounds may be a compound having various ligands. Examples of the ligand include a cyanide ion, a halogen ion, a thiocyanate ion, a nitrosyl ion, water, a hydroxide ion, a pseudohalogen, ammonia, and organic molecules such as amines (methylamine, ethylenediamine and the like), heterocyclic compounds (imidazole, 5-methylthiazole, mercaptoimidazole and the like), urea and thiourea.

To achieve high sensitivity, doping of a metal hexacyanide complex such as K₄[Fe(CN)₆], K₄[Ru(CN)₆] and K₃[Cr(CN)₆] is advantageously conducted.

The rhodium compound can use a water-soluble rhodium compound. Examples of the water-soluble rhodium compound include a rhodium (III) halide compound, a hexachlororhodium (III) complex salt, a pentachloroaquorhodium complex salt, a tetrachloroaquorhodium complex salt, a hexabromorhodium (III) complex salt, a hexamine rhodium (III) complex salt, a trioxyalatorhodium (III) complex salt and K₃Rh₂Brc>.

Examples of the iridium compound include a hexachloroiridium complex salt such as K₂IrCl₆ or K₃IrCl₆, a hexabromoiridium complex salt, a hexamine iridium complex salt and a pentachloronitrosyliridium complex salt.

Examples of the ruthenium compound include hexachlororuthenium, pentachloronitrosylruthenium and K₄[Ru(CN)₆].

Examples of the iron compound include potassium hexacyanoferrate (II) and ferrous thiocyanate.

Examples of the ruthenium compound and osmium compound include water-soluble complex salts described in, for example, JP- A-63 -2042, 1-285941, 2-20852 and 2-20855.

Amount of those compounds added is preferably from 10^'10 to 10^"2 mol/mol Ag, and more preferably from 10^"9 to 10^"3 mol/mol Ag, per mole of the silver halide.

Besides, the invention can preferably use a silver halide containing Pd (II) ion and/or Pd metal. Pd may be uniformly distributed in the silver halide particle, but is preferably contained in the vicinity of a surface layer of the silver halide particle. The term "Pd is contained in the vicinity of a surface layer of the silver halide particle" means that a layer having a palladium content higher than other layers is present within 50 nm in a depth direction from the surface of the silver halide particle.

Such silver halide particles can be prepared by adding Pd in the middle of formation of the silver halide particles, and Pd is preferably added after adding silver ions and halogen ions in the respective total addition amount of 50% or more. Further, it is preferable to make Pd (II) ions be present in the silver halide layer by a method of, for example, adding the same when post-aging.

The Pd-containing silver halide particle contributes to increase rate of physical development or electroless plating, increase production efficiency pf the desired electromagnetic shielding material, and reduce production cost. Pd is well known as an electroless plating catalyst and is used. In the invention, Pd can be localized in the surface layer of the silver halide particle, and as a result, it is possible to save extremely expensive Pd.

In the invention, the content of Pd ion and/or Pd metal contained in the silver halide is preferably from 10^"4 to 0.5 mol/mol Ag, and more preferably from 0.01 to 0.3 mol/mol Ag, to the mole number of silver of the silver halide.

Examples of the Pd compound used include PdCl₄ and Na₂PdCl₄.

In the invention, chemical sensitization conducted in a photographic emulsion can be applied in order to improve sensitivity as a light sensor. Examples of the chemical sensitization method that can be used include chalcogen sensitization such as sulfur sensitization, selenium sensitization or tellurium sensitization; noble metal sensitization such as gold sensitization; and reduction sensitization. Those sensitization methods are used alone or as combinations of those. When the above chemical sensitization methods are used in combination, a combination of sulfur sensitization and gold sensitization, a combination of sulfur sensitization, selenium sensitization and gold sensitization, and a combination of sulfur sensitization, tellurium sensitization and gold sensitization are preferable.

The sulfur sensitization is generally conducted by adding a sulfur sensitizer and stirring an emulsion at high temperature of 40°C or higher for a constant time. The sulfur sensitizer can use the conventional compounds, and for example, other than the sulfur compound contained in gelatin, various sulfur compounds such as thiosulfates, thioureas, thiazoles and rhodanins can be used. The preferable sulfur compounds are thiosulfates and thiourea compounds. The amount of the sulfur sensitizer added varies under various conditions such as pH at chemical ageing, temperature, and size of the silver halide particle, but the amount is preferably from 10^"7 to 10^"2 mol, and more preferably from 10^"5 to 10^"3 mol, per mole of the silver halide.

A selenium sensitizer used in the selenium sensitization can use the conventional selenium compounds. Compounds described in, for example, JP-B-44- 15748 and 43-13489, and JP-A-4-109240 and 4-324855 can be used as the unstable selenium compound.

A tellurium sensitizer used in the tellurium sensitization is a compound that forms silver telluride that is estimated to become a sensitizing nucleus, on the surface or in the inside of the silver halide particle. Specifically, compounds described in, for example, J. Chem. Soc. Chem. Commun., 635 (1980); ditto, 1102 (1979); and ditto, 645 (1979) can be used. In particular, compounds represented by the general formulae (II), (HI) and (IV) in JP- A-5-313284 are preferable.

The amount of the selenium sensitizer and tellurium sensitizer that can be used in the invention varies depending on the silver halide particle use, chemical ageing conditions and the like, but is generally from about 10^"8 to 10^'2, and preferably from about 10^"7 to 10^"3, per mole of the silver halide. The conditions of the chemical sensitization in the invention are not particularly limited. For example, pH is from 5 to 8, p Ag is from 6 to 11, and preferably from 7 to 11, and temperature is from 40 to 95°C, and preferably from 45 to 85°C. Examples of the noble metal sensitizer include gold, platinum, palladium and iridium. Gold sensitization is particularly preferable. Specific examples of the gold sensitizer used in gold sensitization include chorauric acid, potassium chlorooleate, potassium aurithiocyanate, gold sulfide, gold (I) thioglucose and gold (I) thiomannose. The gold sensitizer can be used in an amount of from about 10^"7 to 10^"2 mol, per mole of the silver halide. A cadmium salt, a sulfite salt, a lead salt, a thallium salt or the like may further be present in the silver halide emulsion used in the invention in the course formation or physical ageing of the silver halide particle.

The invention can use reduction sensitization. Examples of a reduction sensitizer that can be used include stannous salts, amines, formamidinesulfinic acid and silane compounds.

A thiosulfonic acid compound may be added to the silver halide emulsion by the method described in EP-A-293917. The silver halide emulsion used in the preparation of the photosensitive material used in the invention may be used alone or mixtures of two or more thereof (for example, a mixture of emulsions having different average particle size, a mixture of emulsions having different halogen composition, a mixture of emulsions having different crystal habit, a mixture of emulsions having different conditions of chemical sensitization, or a mixture of emulsions having different sensitivity). Above all, it is preferable to apply an emulsion having higher sensitivity as approaching to the support as described in JP- A-6-324426. [Exposure]

The invention conducts exposure of a silver salt-contained layer provided on the support. The exposure can be conducted using an electromagnetic wave. Examples of the electromagnetic wave used include lights such as a visible light and an ultraviolet light, and radiations such as X ray. Further, the exposure may utilize a light source having wavelength distribution, and may use a light source having specific wavelength.

The light source can include scanning exposure using a cathode ray tube (CRT). Cathode ray tube exposure device is simple and compact as compared with a device using laser, and therefore is low cost. Further, it is easy to adjust light axis and color. The cathode ray tube used in image exposure uses various illuminants showing luminescence in spectrum region, according to need. For example, one or a combination of at least two of a red illuminant, a green illuminant and a blue illuminant is used. The spectrum region is not limited to the above red, green and blue, and an illuminant showing luminescence in yellow, orange, purple or infrared region is also used. In particular, a cathode ray tube showing white luminescence by combining those illuminants is frequently use. Ultraviolet lamps are preferably used, and g ray of a mercury lamp, i ray of a mercury lamp or the like is also utilized.

In the invention, the exposure can be conducted using various laser beams. For example, the exposure in the invention can preferably use a scanning exposure method using monochromatic high density light such as a gas laser, a light-emitting diode, a semiconductor laser, and a second harmonic generation light source (SHG) combining a semiconductor laser or a solid laser using a semiconductor laser as an excitation light source, with a nonlinear optical crystal. KrF excimer laser, ArF excimer laser, F₂ laser and the like can further be used. To make the system compact and inexpensive, the exposure is preferably conducted using a semiconductor laser, or a second harmonic generation light source (SHG) combining a semiconductor laser or a solid laser with a nonlinear optical crystal. To design a device that is compact and inexpensive, and has long life and stability, the exposure is preferably conducted using a semiconductor laser. As a laser light source, specifically, a red semiconductor laser having a wavelength of from 430 to 460 nm (announced by Nichia Corporation in 48th Applied Physics-Related Combined Lectures in March 2001), a green laser of about 530 nm by wavelength converting a semiconductor laser (oscillation wavelength: about 1,060 nm)by SHG crystal OfLiNbO₃ having a waveguide-shaped reverse domain structure, a red semiconductor laser having wavelength of about 685 nm (Hitachi Type No. HL6738MG), a red semiconductor laser having wavelength of about 650 nm (Hitachi Type No. HL6501MG), and the like are preferably used.

A method of exposing the silver salt-contained layer in pattern shape may conduct with face exposure utilizing a photomask, or may conduct with scanning exposure by laser beam. In this case, refractive exposure using a lens or a reflective exposure using a reflective mirror may be used, and exposure methods such as a contact exposure, a proximity exposure, a reduced projection exposure and a reflective projection exposure can be used.

In the invention, it is preferable to web-transport a long film shaped photosensitive material and expose a photosensitive face of the transported photosensitive material to laser light through a photomask having recorded therein a negative graphic of mesh pattern, from the point of production efficiency.

The exposure embodiment of conducting printing exposure of a pattern with good productivity is further described in the Examples. [Development treatment]

In the invention, development treatment is further conducted after exposing the silver salt-contained layer. The development treatment can use, general development treatment technologies used in silver salt photographic films and printing papers, films for printing plate-making, emulsion coating layers for photomask and the like.

The development treatment can select any of a negative development treatment and a reverse development treatment. Further, it can be conducted with any of chemical development and physical development (in the embodiment of the invention, accurately dissolving physical development).

The chemical development and dissolving physical development intended herein has the meaning entirely expressed by the terms generally used in the art of this field, and are explained in general texts of photographic chemistry, for example, Shin-ichi Kikushi, Photographic Chemistry (Kyoritsu Shuppan Co., 1955) and C. E. K. Mees, The Theory of Photographic Processes, 4^th ed., 373-377 (Maclillan, 1977).

The chemical developer may be a black-and-white developer or a color developer (may not color develop) and is not particularly limited, so long as a developed silver is obtained. However, a black-and-white developer is preferable. The black-and-white developer than can be used includes PQ developer, MQ developer and MAA developer (a metol-ascorbic acid developer). For example, developers such as CN- 16, CR-56, CP45X, FD-3 and PAPITOL according to the specified formulation by Fuji Photo Film Co., and C-41, E-6, RA-4 and D-72 according to the specified formulation by Eastman Kodak; developers contained in their kits; lith developers or contrast developers known as formulation names of D-19, D-85 and D-8; and the like can be used. In the embodiment of dissolving physical development, thiosulfates (sodium salt, ammonium salt and the like) or thiocyanates (sodium salt, ammonium salt and the like) may be added as a silver halide solubilizer to the above each developer, and it is preferable to add the same to a high activity developer such as D-19, D-85, D-8 or D-72.

In the invention, by conducting the above exposure and development treatment, a metallic silver portion, preferably a pattern-like metallic silver portion, is formed, and simultaneously, a light-transmitting part described hereinafter is formed. Developer composition and development treatment step

In the invention, any of the above-described developers can be used, and a black-and-white developer is preferably used. As a developing agent, a color developing agent and a black-and-white developing agent are preferably, and in particular, an ascorbic acid developing agent and a dihydroxybenzene developing agent can preferably be used. Examples of the ascorbic acid developing agent include ascorbic acid, isoascorbic acid, erythorbic acid and its salt (Na salt or the like). Erythorbic acid Na is preferable from the point of cost. Examples of the dihydroxybenzene developing agent include hydroquinone, chlorohydroquinone, isopropyl hydroquinone, methyl hydroquinone and hydroquinone monosulfonate. Of those, hydroquinone is preferable. The ascorbic acid developing agent and dihydroxybenzene developing agent may use or may not use together with an auxiliary developing agent particularly showing an ultra-additive property. Examples of the auxiliary developing agent particularly showing an ultra-additive property to the ascorbic acid developing agent and dihydroxybenzene developing agent include l-phenyl-3-pyrazolidones and p-aminophenols.

Specific examples of l-phenyl-3-pyrazolidone or its derivative used as the auxiliary developing agent include l-phenyl-3-pyrazolidone,

1 -phenyl-4,4-dimethyl-3 -pyrazolidone and

1 -phenyl-4-methyl-4-hydroxymethyl-3 -pyrazolidone.

Examples of the p-aminophenol series auxiliary developing agent include N-methyl-p-aminophenol, p-aminophenol, N-(β-hydroxyethyl)-p-aminophenol and N-(4-hydroxyphenyl)glycine. Above all, N-methyl-p-aminophenol is preferable. It is preferable that the hydroxybenzene series developing agent is generally used in an amount of from 0.05 to 0.8 mol/liter. In the invention, it is used in an amount of preferably 0.23 mol/liter or more, and more preferably from 0.23 to 0.6 mol/liter. Where dihydroxybenzenes and l-phenyl-3-pyrazolidones or p-aminophenol are used in combination, the former is used in an amount of preferably from 0.23 to 0.6 mol/liter, and more preferably from 0.23 to 0.5 mol/liter, and the latter is used in an amount of preferably 0.06 mol/liter or less, and more preferably from 0.03 to 0.003 mol/liter.

Immersion potential, that is, redox potential, of the developer is a combined potential of redox property of constituents of the developer, and is mainly determined by the developing agent and pH. The redox potential is preferably poor than 290 mV vs SCE, more preferably poor than -320 mV vs SCE, and further preferably poor than -34O mV vs SCE.

The redox potential of the developer is made to be poor than 290 mV vs SCE by using the agent listed as the preferable developing agent described above and controlling pH according to the kind of the developing agent selected. The pH value is the side of preferably from 0 to 2, and more preferably 0.5 to 1.5, higher than pK value of the developing agent, and is appropriately selected according to the kind of the developing agent.

In the invention, both a development initiating solution (i.e., a mother liquid charged in a developer tank as a fresh liquid) and a development replenisher preferably have pH buffering ability that pH rise is 0.5 or less when 0.1 mol of sodium hydroxide is added to 1 liter of the respective solution. A method of confirming that the development initiating solution or development replenisher (sometimes called a developer in the combination thereof) has the pH buffering ability is as follows. pH of the development initiating solution or development replenisher to be tested is adjusted to 10.5, and 0.1 mol of sodium hydroxide is added to the respective solution. The pH value of the respective solution at that time is measured. When rise of the pH value is 0.5 or less, it is judged that the solution has the above-prescribed pH buffering ability. In the production method of the invention, it is particularly preferable to use the development initiating solution and development replenisher showing the pH rise of 0.4 or less when the above test is conducted.

A method of imparting the above properties to the development initiating solution and development replenisher preferably uses a buffering agent. Examples of the buffering agent that can be used include carbonates, boric acids described in JP-A-62- 186259, saccharides (such as saccharose) described in JP-A-60-93433, oximes (such as acetoxime), phenols (such as 5-sulfosalilyclic acid) and tertiary phosphates (such as sodium salt and potassium salt). Carbonates and boric acid are preferably used. The buffering agent (particularly, carbonates) is used in an amount of preferably 0.25 mol/liter or more, and more preferably from 0.25 to 1.5 mol/liter.

In the invention, the pH of the development initiating solution is in a range of preferably from 9.0 to 11.0, and particularly preferably from 9.5 to 10.7. The pH of the development replenisher and the pH of the developer tank in continuous treatment are also in this range. An alkali agent used for pH setting can use general water-soluble inorganic alkali metal salts (such as sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate).

In the production method of the light-transmitting conductive film and electromagnetic shielding film of the invention, the addition amount (replenishing amount) of the development replenisher in the developer is 645 milliliters or less, preferably from 30 to 484 milliliters, and particularly preferably from 100 to 484 milliliters, when treating 1 m² of a photosensitive material. The development replenisher may have the same composition as the development initiating solution, but preferably have a concentration higher than the initiating solution with the amount commensurate to replenish a consumed amount of the component consumed in the development.

The developer (hereinafter sometimes simply referred to as a "developer" by combining a development initiating solution and a development replenisher) in developing the photosensitive material of the invention can contain additives generally used (such as preservatives and a chelating agent). Examples of the preservatives include sulfites such as sodium sulfite, potassium sulfite, lithium sulfite, ammonium sulfite, sodium bisulfite, potassium metabisulfite and sodium formaldehyde besulfite. The sulfite is used in an amount of preferably 0.20 mol/liter or more, and more preferably 0.3 mol/liter or more. However, where the sulfite is added excessively, it causes silver stain in the developer. Therefore, the upper limit of the sulfite added is desirably 1.2 mol/liter. Particularly preferably, the sulfite is used in an amount of from 0.35 to 0.7 mol/liter. As the preservatives of the dihydroxybenzene series developing agent, the ascorbic acid derivative may be used in a small amount together with the sulfites. The ascorbic acid derivative used herein is the same as the ascorbic acid as the developing agent described above, and includes erythorbic acid that is its steric isomer, and an alkali metal salt thereof (sodium or potassium salt). The sodium erythorbate is preferably used as the ascorbic acid derivative from material cost. The amount of the ascorbic acid derivative added is in a range of preferably from 0.03 to 0.12, and particularly preferably from 0.05 to 0.10, in molar ratio to the dihydroxybenzene series developing agent. When the ascorbic acid derivative is used as the preservatives, a boron compound is not preferably contained in the developer. Examples of the additives that can be added other than the above include development inhibitors such as sodium iodide and potassium iodide; organic solvents such as ethylene glycol, diethylene glycol, triethylene glycol and dimethylformamide; and development accelerators such as an alkanol amine (such as diethanolamine and triethanolamine), and imidazole or its derivative. Further, the developer may contain mercapto compounds, imidazole compounds, benztriazole compound or benzimidazole compounds as an antifogging agent or a black pepper inhibitor. Specific examples of the benzimidazole compound include 5-nitroindazole, 5-p-nitrobenzoylaminoindazole, l-methyl-5-nitroindazole, 6-nitroindazole, 3 — methyl-5-nitroindazole,

5-nitrobenzimidazole, 2-isopropyl-5-nitrobenzimidazole, 5-nitrobenztriazole, sodium 4-[(2-mercapto-l,3,4-thiadiazol-2-yl)thio]butanesulfonate, 5-amino-l,3,4-thiadiazol-2- thiol, methylbenzotriazole, 5-methylbenztriazole and 2-mercaptobenztiiazole. The content of those benzimidazole compounds is generally from 0.01 to 10 mmol, and preferably from 0.1 to 2 mmol, per liter of the developer.

The developer can further contain various organic and inorganic chelating agents. Examples of the inorganic chelating agent that can be used include sodium tetrapolyphosphate and sodium hexametaphosphate. Examples of the organic chelating agent that can be used include organic carboxylic acid, aminopolycarboxylic acid, organic phosphonic acid, aminophosphonic acid and organic phosphonocarboxylic acid.

Examples of the organic carboxylic acid include acrylic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, maleic acid, itaconic acid, malic acid, citric acid and tartaric acid.

Examples of the aminopolycarboxylic acid include iminodiacetic acid, nitrilotriacetic acid, nitrilotripropionic acid, ethylenediamine monohydroxyethyltriacetic acid, ethylenediamine tetraacetic acid, glycol ester tetraacetic acid, 1,2-diaminopropane tetraacetic acid, diethylene triamine pentaacetic acid, triethylene tetramine hexaacetic acid, l,3-diamino-2-propanol tetraacetic acid, glycol ether diamine tetraacetic acid, and compounds described in JP-A-52-25632, 55-67747 and 57-102624, and JP-B-53-40900.

The amount of those chelating agents added is preferably from IxIO^"4 to IxIO^"1 mol, and more preferably from IxIO^"3 to IxIO^"2 mol, per liter of the developer.

The compounds described in JP- A-61-267759 can be used in the developer as a dissolution assistant. The developer may further contain a color regulator, a surfactant, a defoaming agent, a film hardener, and the like according to need. The development treatment temperature and time are correlated, and are determined in relation to the overall treatment time. In general, the development temperature is preferably from about 20 to 50°C, and more preferably from 25 to 45⁰C. The development time is preferably from 5 seconds to 2 minutes, and more preferably from 7 seconds to 1 minute and 30 seconds.

The embodiment that the developer is condensed and is diluted in using, that is, the embodiment of supplying in a form of a liquid-condensed developer, is preferable from the purposes of transporting cost reduction, package material cost reduction, space saving and the like. Converting a salt component contained in the developer into potassium chloride is effective for concentration of the developer. The "concentration of developer" used herein is an expression commonly used in the art of this field, and means "richness", not meaning "concentration" by vacuum evaporation or the like. [Fixing treatment] Subsequent to the development treatment, fixing treatment is preferably conducted for the purpose of removing silver salt in an unexposed area for stabilization, but such a fixing treatment can be omitted in the invention. In particular, when the development treatment is conducted by dissolving physical development, generally the silver halide in the unexposed area is considerably dissolved in the development course, and disappears. However, when the development is conducted by chemical development type development formulation, transparency of the unexposed area, that is, a light-transmitting part, is preferably increased by fixing treatment.

The fixing treatment is not always required to conduct subsequent to the development treatment, and may be conducted after an electrolytic plating step described hereinafter.

The fixing treatment in the invention can use general fixing treatment technologies used in color photographic or black-and-white silver salt photographic films, photographic papers, printing plate-making films, X ray photographic films, emulsion masks for photomast, and the like.

Preferably components of a fixing solution used in the fixing step are as follows.

That is, the fixing solution preferably contains fixing agents such as sodium thiosulfate, ammonium thiosulfate and potassium thiosulfate; and if necessary, pH buffers or preservers such as tartaric acid, citric acid, gluconic acid, boric acid, iminodiacetic acid, 5-sulfosalicyclic acid, glucoheptanoic acid, tiron and their salts; hard water softeners such as ethylenediamine tetraacetic acid, diethylenetriamine pentaacetic acid, nitrilotriacetic acid and their salts; and the like. However, boric acid is not preferably contained from the standpoint of the recent environmental protection. Examples of the fixing agent in the fixing solution used in the invention include sodium thiosulfate and ammonium thiosulfate, and ammonium thiosulfate is preferable from the point of fixing rate. However, sodium thiosulfate may be used in view of water quality regulations of total nitrogen content from the standpoint of the recent environmental protection. The amount of those fixing agents used can appropriately vary, and is generally from about 0.1 to 2 mol/liter. The particularly preferable amount is from 0.2 to 1.5 mol/liter. If desired, the fixing solution can contain film hardeners (such as a water-soluble aluminum compound), preservers (such as sulfites and bisulfϊtes), pH buffers (such as acetic acid), pH regulators (such as ammonia and sulfuric acid), chelating agents, surfactants, wetting agents, fixing accelerators, and the like.

Examples of the surfactant include anionic surfactants such as sulfated products and sulfonated products, and amphoteric surfactants described in JP-A-57-6740. The conventional defoaming agents may be added to the fixing solution.

Examples of the wetting agent include alkanolamine and alkylene glycol. Examples of the fixing accelerator include thiourea derivatives described in JP-B-45-35754, 58-122535 and 58-122536; alcohols having triple bond in the molecule; thioether compounds described in US Patent 4,126,459; and mesoionic compounds described in JP-A-4-229860. The compounds described in JP-A-2-44355 may be used as the fixing accelerator. Examples of the pH buffer that can be used include organic acids such as acetic acid, malic acid, succinic acid, tartaric acid, citric acid, oxalic acid, maleic acid, glycolic acid and adipic acid; and inorganic buffers such as boric acid, phosphates and sulfites. The pH buffers preferably used are acetic acid, tartaric acid and sulfites. The pH buffer is used for the purpose of preventing pH rise of the fixing agent by the carry-on developer, and is used in an amount of preferably from about 0.01 to 1.0 mol/liter, and preferably from about 0.02 to 0.6 mol/liter. The pH of the fixing solution is in a range of preferably from 4.0 to 8.0, and particularly preferably from 4.5 to 7.5.

In the invention, a water-soluble halide is preferably added in order to highly activate the fixing solution so as to make rapid fixing possible. The preferable water-soluble halide is bromides, iodides of alkali metals, ammonium bromide and ammonium iodide, and the preferable alkali metal salt is sodium salts and potassium salts. The total addition amount of the water-soluble halides is from 0.035 to 0.5 mol/liter, and more preferably from 0.05 to 0.4 mol/liter. The water-soluble halide particularly preferably contains a water-soluble iodide such as potassium iodide, sodium iodide and ammonium iodide. In this case, the amount of the water-soluble iodide added is from 0.005 to 0.05 mol/liter.

The water-soluble halide has the function to increase a metal deposition rate in a plating step subsequent to the fixing step, in addition to adjusting pAg high. In particular, the effect of iodine ion is large.

Examples of the film hardener in the fixing solution of the present invention include a water-soluble aluminum salt and a chromium salt. The preferable compound as the film hardener is the water-soluble aluminum salt, and examples thereof include aluminum chloride, aluminum sulfate and potassium alum. The amount of the film hardener added is preferably from 0.01 to 0.2 mol/liter, and more preferably from 0.03 to 0.08 mol/liter.

The fixing temperature in the fixing step is that the fixing treatment temperature and time are mutually related, and is therefore determined by the relationship with the overall treatment time. The rapid fixing solution having high activity of the invention has the activity to complete the fixing of silver halide particles in the unexposed area at from 30 to 60°C for from 5 to 40 seconds. The fixing temperature is preferably from 30 to 60°C, and more preferably from 35 to 55°C. The fixing time is preferably from 5 to 40 seconds, and more preferably from 7 to 30 seconds.

The amount of the fixing solution replenished is preferably 10,600 ml/m² or less, and more preferably 700 ml/m² or less, to the treating amount of the photosensitive material. The concentration of the replenisher is set to a concentration commensurate with compensating consumption during treatment under the determined replenishing amount. [Water washing treatment, stabilization treatment, and the like]

The photosensitive material having development and fixing treatment applied thereto is preferably subjected to water washing treatment and stabilization treatment (called a water washing-alternative stabilization treatment) subsequent to or after the plating treatment described hereinafter, or after the development and the fixing treatment, and then after plating treatment. The water washing treatment and stabilization treatment are conducted in a water washing amount (or replenishing amount of a solution for stabilization) of generally 20 liters or less per 1 m² of the photosensitive material, and can also be conducted in a replenishing amount of 3 liters or less (including zero, that is, water washing with storage water). This makes it possible to conduct water-saving treatment, and further makes piping for arranging an automatic processor unnecessary. A multistage countercurrent method (two sages, three stages, and the like) is hitherto known as a method of reducing the replenishing amount of washing water. Where this multistage countercurrent method is applied to the production method of the invention, the photosensitive material after fixing is gradually successively contacted and treated in a normal direction, i.e., a direction of the treating liquid that is not contaminated with the fixing solution, and this enables further efficient water washing to conduct. When the water washing is conducted with a small amount of water, it is more preferable to arrange a washing tank of a squeeze roller or a crossover roller. Further, to reduce environmental load relating to waste water pollution that becomes the problem when washing with small amount of water, addition of various oxidizing agents or filter filtration may be combined. Additionally, in the above method, a part or the whole of a overflow liquid from a water washing bath or a stabilization bath, generated by replenishing mildewproof-treated water to the water washing bath or the stabilization bath according to the treatment can be utilized to a treating liquid having a fixing ability in the previous treatment step as described in JP-A-60-235133. Further, to prevent ununiform water bubbles that are liable to generate when small water washing and/or to prevent that the treating agent components adhered to a squeeze roller transfer to the treated film, a water-soluble surfactant or a defoaming agent may be added.

In the above water washing treatment or stabilization treatment, dye adsorbents described in JP-A-63-163456 may be provided in a water washing tank to prevent contamination by a dye eluted from the photosensitive material. Further in the stabilization treatment subsequent to the water washing treatment, a bath containing the compounds described in each of JP-A-2-201357, 2-132435, 1-102553 and 46-44446 may be used as a final bath of the photosensitive material. In this case, ammonium compounds, metal compounds such as Bi and Al, fluorescent bleaching agents, various chelating agents, film pH regulators, film hardeners, fungicides, mildew-proofing agents, alkanol amines, surfactants and like can be added according to need. Water used in the water washing step and stabilization step preferably uses tap water, and further deionized water and water sterilized with ultraviolet germicidal lamp, various oxidizing agents (ozone, hydrogen peroxide, chlorates, and the like). Further, washing water containing the compounds described in JP-A-4-39652 and 5-241309 may be used. The bath temperature and time in the water washing treatment or stabilization treatment are preferably from 0 to 50°C and from 5 seconds to 2 minutes, respectively.

The treating liquids of the developer, the fixing solution and the like used in the invention are preferably stored with a packaging material having low oxygen permeability described in JP- A-61-73147. Further, it is preferable to prevent evaporation and air oxidation of a liquid by decreasing contact area of the treating tank with air. Roller transport-typed automatic processor can use processors described in, for example, US Patents 3,025,779 and 3,545,971. The roller transport-typed processor preferably comprises four steps of development, fixing, water washing and drying. In the invention, it is most preferable to follow the four steps, although not excluding other steps (such as stop step). The four steps may include stabilization step in place of water washing step.

The mass of the metallic silver contained in the exposed area after development treatment is preferably the content of 50 mass% or more to the mass of silver contained in the exposed area before exposure as far as the silver halide photosensitive material applied to the invention is concerned. The content of 80 mass% or more is more preferable. When the mass of silver contained in the exposed area is 50 mass% or more to the mass of silver contained in the exposed area before exposure, high conductivity can be obtained, which is preferable.

Tone after development treatment in the invention is not particularly limited, but preferably exceeds 4.0. When the tone after development treatment exceeds 4.0, conductivity of the conductive metal part can be increases while maintaining high transparency of the light-transmitting part. The means to make the tone 4.0 or more includes doping with rhodium ion or iridium ion as described before. [Electrolytic plating treatment]

Electrolytic plating treatment for supporting conductive metal particles on the metallic silver part is preferably conducted for the purpose of imparting conductivity to the metallic silver part formed by the above-described exposure and development treatment.

In the invention, the electrolytic treatment is conducted subsequent to the development treatment, or after conducting the fixing treatment after the development treatment, or after the development treatment or after water washing or water washing-alternative rinsing after the development treatment. The stage when the electrolytic plating is conducted can appropriately be selected.

The electrolytic plating in the invention is preferable than electroless plating in the point that it can be conducted under mild electrolyte conditions that metal deposition does not cause in the unexposed area (stability is high), and further, high speed plating of 5 μm/hr or more is possible. The plating treatment can use various additives such as ligands such as EDTA from the standpoint of increasing stability of a plating liquid.

Metal species used in the electrolytic plating and plated are the same as the metal species described in the item of electroless plating, and the preferable metal species are also the same. Copper and silver plating are particularly preferable.

The electrolyte can use any electrolyte so long as it can dissolve a metal compound of a metal to be plated to a necessary concentration, and sufficiently low solution resistance suitable to electrolysis (the sum of contact resistance to developed silver as an electrode and current-carrying resistance) can be secured. Therefore, the electrolyte is appropriately selected according to the metal compound used. In general, the metal to be plated is copper, silver or the like. Therefore, an aqueous solution of an inorganic acid such as sulfuric acid, hydrochloric acid or nitric acid is preferable. From that silver and copper are liable to form an ammine complex or a hydroxyamino complex, ammonium hydroxide (aqueous ammonia) and an alkanol amine aqueous solution (preferably ethanolamine, diethanolamine or triethanolamine aqueous solution) are also preferably used.

Those electrolytes (acids, ammonium hydroxide or alkanolamines) are used in a concentration of 0.1 to 10 mol/liter, preferably from 0.2 to 8 mol/liter, and particularly preferably from 0.25 to 5 mol/liter. The concentration of the metal compound of the plating metal is from 0.05 to 10 mol/liter, preferably from 0.07 to 5 mol/liter, and particularly preferably from 0.1 to 3 mol/liter.

Plating rate in the electrolytic plating treatment can be under mild conditions, and high speed plating of 5 μm/hr or more is also possible. The electroless plating treatment can use various additives such as ligands such as EDTA from the standpoint of increasing stability of a plating liquid.

Temperature of the plating solution in the electrolytic plating is preferably from 10 to 60°C, more preferably from 20 to 50°C, and particularly preferably from 25 to 45°C. Charge time can appropriately be controlled so as to obtain the desired metal coating thickness. Applied voltage (within an allowable range), solution composition and temperature are controlled such that the charge time is from 10 to 600 seconds, preferably from 20 to 450 seconds, and particularly preferably from 30 to 300 seconds.

As the example of the preferable metal compounds and plating solution composition, in the case of copper plating, a plating solution containing from 30 to 300 g/liter of copper sulfate pentahydrate, and from 30 to 300 g/liter of sulfuric acid can be used. In the case of silver plating, a neutral to acidic aqueous solution and an amnionic alkali aqueous solution, containing from 30 to 300 g/liter of silver nitrate can be used. In the case of nickel plating, a solution containing nickel sulfate or nickel hydrochloride can be used, and in the case of silver plating, a solution containing silver cyanide can be used. Additives such as surfactants, sulfur compounds and nitrogen compounds may be added to the plating solution.

Representative example of the electrolytic plating embodiment in the invention is described below, but the invention is not construed as being limited thereto. A plating machine for suitably carrying out the plating treatment according to the invention preferably has the constitution that a film successively unreeled from an unreeling reel (not shown) having the film wound thereon is sent to an electrolytic plating bath, and the film after plating is successively wound on a winding reel (not shown), similar to the conventional machine.

Fig. 1 show one example of an electrolytic plating bath suitably used in the plating treatment according to the invention. An electrolytic plating machine 10 shown in Fig. 1 can continuously apply the plating treatment to a long film 16. The arrow shows a transporting direction of the film 16. The electrolytic plating machine is equipped with an electrolytic cell 11 storing a plating solution 15. A pair of anode plates 13 is provided in parallel in the electrolytic cell 11. In the inside of the anode plates, a pair of guide rollers 14 is rotatably provided in parallel to the anode plates 13. The guide roller 14 is movable in a vertical direction, and by this, the plating treatment time of the film 16 can be adjusted.

Feeder rollers (cathodes) 12a and 12b as a pair that guide the film 16 to the electrolytic bath and further feed electric current to the film 16 are rotatably provided on the upper part of the electrolytic cell 11. Further, a liquid cut roller 17 is rotatably provided on the upper part of the electrolytic cell 11 and the lower part of the feeder roller 12b at the outlet side.

The anode plates 13 are connected to a plus terminal of a power supply through an electric wire (not shown), and the feeder rollers 12a and 12b are connected to a minus terminal of a power supply.

The film 16 is set in a state of winding on a unreeling reel (not shown), and the film 16 is wound around a tranport roller (not shown) such that the face at the side to be plated of the film 16 contacts the feeder rollers 12a and 12b.

Voltage is applied to the anode plates 13 and the feeder rollers 12a and 12b, and the film 16 is transported with contacting the feeder rollers 12a and 12b. The film 16 is introduced into the electrolytic cell 11 and dipped in the plating solution 15 to form a copper plating. The plating solution 15 deposited on the film 16 is wiped off when the film 16 passes through the liquid cut roller 17, and recovered in the electrolytic cell 11. This procedure is repeated in plural electrolytic plating cells, and finally the film 16 is washed with water and then wound around a winding reel (not shown).

The transport speed of the film 16 is set in a range of from 1 to 10 m/min. The transport speed of the film 16 is in a range of preferably from 1 to 10 m/min, and more preferably from 2 to 5 m/min.

The number of the electrolytic cell is not particularly limited, but is preferably 2 to 10, and more preferably 3 to 6.

The voltage applied is preferably in a range of from 0.5 to 100V, and more preferably in a range of from 1 to 60V.

The feeder rollers 12a and 12b are preferably contacted with the entire surface of the film (substantially electrically contacted portion in the contacted area is 80% or more).

It is preferable for the conductive metal part plated by the above plating treatment to have smaller thickness as the use purpose of an electromagnetic shielding material of a display, because a viewing angle of a display spreads with decreasing the thickness. Further, as the use purpose of a conductive wiring material, small film thickness is required from the demand of high density. From this standpoint, a layer comprising the plated conductive metal has a thickness of preferably less than 9 μm, more preferably from 1 to 6 μm, and further preferably from 1 to 5 μm. [Electroless plating treatment] (Activation treatment)

In the invention, electroless plating may be conducted to the photosensitive material after the development treatment, in place of conducting electrolytic plating. When the electroless plating is conducted, it is further preferable to apply an activation treatment in the point of increasing the electroless plating rate. The activation treatment enables metal deposition to the conductive metal part formed during development in the electroless plating to be easy.

An activation liquid is a liquid having an ability to remove plating inhibitory components formed on the surface of the conductive metal part after the development treatment.

The plating inhibitory component means oxides, sulfides and halides formed on the surface of the conductive metal part, and specific examples thereof include silver sulfide and silver iodide.

The liquid having an ability to remove plating inhibitory components is a liquid containing reducing substances, metal solubilizers, sulfide solubilizers and/or halogen solubilizers.

Examples of the reducing substance include alkali metal salts of boron hydride (tetrahydroboric acid), preferably sodium borohydride and potassium borohydride. Concentration of the reducing substance in the activation bath is from 0.005 to 10 g/liter, preferably from 0.01 to 6 g/liter, and more preferably from 0.015 to 0.8 g/liter.

The metal solubilizer includes a water-soluble silver salt, preferably silver nitrate. Concentration of the metal solubilizer in the activation bath is from 5 to 1,000 g/liter, preferably from 10 to 1,000 g/liter, and more preferably from 30 to 1,000 g/liter.

The sulfide solubilizer is a strong acid having pK of 2 or less, and examples thereof include nitric acid, sulfuric acid and hydrochloric acid. Concentration of the sulfide solubilizer in the activation bath is from 0.5 to 200 g/liter, preferably from 1 to 180 g/liter, and more preferably from 3 to 120 g/liter.

Examples of the silver halide solubilizer include alkali halides, preferably sodium chloride, potassium chloride and ammonium chloride. Concentration of the silver halide sulubilizer in the activation bath is from 0.5 to 100 g/liter, preferably from 5 to 80 g/liter, and more preferably from 10 to 60 g/liter.

The activation treatment has the characteristic to contain at least one compound selected from the above-described reducing substances, metal solubilizers, sulfide solubilizers and/or halogen solubilizers. By this bath treatment, there is not adverse effect that the developed silver surface is impaired by the adsorbed substance, and plating or physical development is effectively conducted, thereby the conductive metal film having excellent conductivity is formed. The reason that conductivity of the light-transmitting conductive film such as a electromagnetic shielding film or a transparent electrode obtained by the activation bath of the invention is considered to be that the electrodeposition inhibitory substance on the surface of the developed silver is removed from the surface by the compounds in the above-described groups (1) to (4), and clean surface is secured. Additionally speaking, as a result of analyzing the surface of the developed silver formed by black-and-white development of the photosensitive material, binding energy peak due to the bond of Ag-I or Ag-S is appeared, but when treated with the above-described compounds, extinction, decrease or transfer of those peaks are observed. This proves the above estimated action mechanism.

From this point, the above-described activation bath quite differs from the conventional activation baths, that is, a treatment bath having an intensification action by a noble metal compound bath (for example, see JP-A-2004-269992) represented by a palladium compound that reinforces a metal nucleus to be plated, in composition and action mechanism. However, the above-described activation bath is called an activation bath on function.

Dipping time of the activation bath is from 10 seconds to 10 minutes, and preferably from 30 seconds to 5 minutes.

Temperature of the activation bath of the invention is from 15 to 60°C, and preferably from 25 to 55°C. [Electroless plating]

The electroless plating in the invention can use the conventional electroless plating technologies, and for example, can use the electroless plating technologies used in printing wiring boards and the like. The electroless plating is preferably an electroless copper plating.

Examples of chemical species contained in the electroless copper plating solution include copper sulfate; copper chloride; formalin or glyoxylic acid as a reducing agent; EDTA or triethanolamine as a ligand of copper; and polyethylene glycol, yellow prussiate of potash or bipyridine as additives for improving stabilization of a bath and smoothness of a coating film. Examples of the electrolytic copper plating bath include a copper sulfate bath and a copper pyrophosphate bath.

Plating rate in electroless plating treatment can be conducted under mild conditions. High speed plating of 5 μm or more is also possible.

Thickness of the conductive metal part having electroless plating treatment applied thereto is the same as described in the electrolytic plating treatment. [Blackening treatment]

The electromagnetic shielding film according to the invention may be subjected to blackening treatment. The blackening treatment is conducted after development and fixing treatments, but may be conducted after the plating treatment where the plating treatment is applied to the film.

The blackening treatment is disclosed in, for example, JP-A-2003-188576. The blackened layer formed by the blackening treatment can have antireflective property imparted thereto, in addition to an antirust effect. The blackening treatment can be formed by, for example, Co-Cu alloy plating, and by forming the blackened layer on the conductive metal part, reflection of its surface can be prevented. To sufficiently impart antireflective property, the blackening treatment is conducted such that the blackened layer covers preferably 20% or more, and more preferably 30% or more, of the conductive metal part surface. Chromate treatment may further be applied to the surface as antirust treatment. The chromate treatment forms an antirust coating by dipping in a solution comprising chromic acid or bichromate as a main component, and drying, and can be applied to one side or both sides of the conductive metal part according to need. Commercially available chromate-treated copper foil and the like may be utilized.

Another example of the constitution containing the blackened layer may be a constitution described in JP-A- 11 -266095. That is, it is a constitution that a first blackened layer is provided on a conductive metal part, the above-described electrolytic plating is applied to the first blackened layer, and a second blackened layer is formed on this plating. To conduct the electrolytic plating on the first blackened layer, at least the first blackened layer must be conductive. This conductive blackened layer can be formed using a compound of nickel (Ni), zinc (Zn), copper (Cu) or the like, or an electrodepositable ionic polymer material such as an electrodeposition coating material.

A method of providing a blackened layer is known (for example, see JP-A- 11 -266095, Fig. 5). For example, a transparent support having a conductive metal part formed thereon is dipped in an electrolyte containing a blacking material, and is plated by an electrochemical method. In the invention, the electrolyte bath containing the blacking material (black plating bath) can use a black plating bath comprising nickel suflate as a main component, and can further similarly use the commercially available black plating bath. Specifically, a black manufactured by Shimizu Co., Ltd. (trade name: NOBLOY SNC, Sn-Ni alloy series), a black plating bath manufactured by Nippon Kagaku Sangyo Co., Ltd. (trade name: Nikka Black, Sn-Ni alloy series), a black plating bath manufactured by Kinzoku Kagaku Kogyo Co., Ltd. (trade name: Ebony Chrome 85 series, Cr series), and the like can be used. In the invention, various black plating baths such as Zn series, Cu series and the like can be used as the black plating bath. After applying conductive plating and forming conductive mesh patterns, a second blackened layer is formed thereon. For example, when a metal of the electrolytic plating is Cu, the surface of Cu is treated with a hydrogen sulfide (H₂S) solution to blacken as copper sulfide (CuS), thereby the second blackened layer is formed. In the invention, a blackening agent for the second blackened layer can easily be produced using a sulfide series compound, and there are various commercially available treating agents. For example, trade names: Copper Black CuO and CuS, and selenium series Copper Black No. 65 (products of Isolate Kagaku Kenkyusho); trade name: Ebonol C Specfial (a product of Meltex Inc.); and the like can be used. [Oxidation treatment]

In the invention, oxidation treatment is preferably conducted to the silver metal portion after development treatment and the conductive metal part formed after plating treatment. By conducting the oxidation treatment, for example where a metal is slightly deposited on the light-transmitting part, the metal is removed, and permeability of the light-transmitting part can be made almost 100%.

The oxidation treatment includes the conventional methods using various oxidizing agents, such as Fe(III) ion treatment. The oxidation treatment can be conducted after exposure and development treatment of the silver salt-contained layer, or after plating treatment, and further may be conducted after development treatment and after plating treatment, respectively. [Conductive metal part]

The conductive metal part in the invention is described below.

In the invention, the conductive metal part is formed by subjecting the metallic silver portion formed by the above-described exposure and development treatment to plating treatment, thereby supporting conductive metal particles on the metallic silver portion. There is the case that the metallic silver is formed on the exposed area, and there is the case that the metallic silver is formed on the unexposed area by, for example, using an autopositive material as a photosensitive material, or using a reverse development in the development treatment. In the invention, the metallic silver is preferably formed on the exposed area in order to increase transparency.

In addition to silver and copper described before, examples of the conductive metal supported on the metal part includes metals such as aluminum, nickel, iron, gold, cobalt, tin, stainless steel, tungsten, chromium, titanium, palladium, platinum, manganese, zinc and rhodium, and particles of alloys comprising mixtures of those metals. The conductive metal is preferably particles of copper, aluminum or nickel from the standpoints of conductivity, cost and the like. In the case of imparting magnetic field shielding property, a paramagnetic metal is preferably used as the conductive metal.

The conductive metal contained in the conductive metal part is preferably copper from the standpoints of increasing contrast and preventing that the conductive metal part is oxidized with the lapse of time and discolored, and the conductive metal having at least its surface blackening-treated is further preferable. The blackening treatment can be conducted using the method conducted in a print wiring board field. For example, the blackening treatment can be conducted by treating in an aqueous solution of sodium chlorite (31 g/liter), sodium hydroxide (15 g/liter) and trisodium phosphate (12 g/liter) a 95°C for 2 minutes.

The conductive metal part contains silver in an amount of preferably 50 mass% or more, and more preferably 60 mass%, to the total mass of metals contained in the conductive metal part. When silver contains 50 mass% or more, time required for the plating treatment can be shortened, thereby improving productivity and reducing costs.

When copper and palladium are used as the conductive metal particles forming the conductive metal part, the total mass of silver, copper and palladium is preferably 80 mass% or more, and more preferably 90 mass% or more, to the total mass of metals contained in the conductive metal part.

The conductive metal part in the invention supports the conductive metal particles, and therefore obtains good conductivity. For this reason, the electromagnetic shielding film (conductive metal part) of the invention has a surface resistance value of preferably 10³ Ω/square or less, more preferably 2.5 Ω/square or less, and further preferably 1.5 Ω/square or less.

When the conductive metal part of the invention is for use as an optically transparent electromagnetic shielding material, it preferably has a geometric shape comprising combination of triangles (for example, equilateral triangle, isosceles triangle and right triangle), quadrangle (such as square, rectangle, rhombus, parallelogram and trapezoid), (regular) n-gon (such as (regular) hexagon and (regular) octagon), circle, ellipse, star and the like, and more preferably has a mesh shape comprising those geometric shapes. A triangular shape is most effective from the standpoint of EMI shielding property. However, from the standpoint of visible light transmission property, aperture ratio increases and the visible light transmission property increase, as n of (regular) n-gon increases, in the case of the same line width. This is advantageous.

When the conductive metal part is for use as a conductive wiring material, shape of the conductive metal part is not particularly limited, and an optional shape can appropriately be determined according to the purpose.

In the use of the optically transparent electromagnetic shielding material, the conductive metal part preferably has a wire width of 40 μm or less, and wire distance of 50 μm or more. For the purpose of the conductive metal part as ground connection, the wire width may have a portion wider than 20 μm. From the standpoint of making an image stand out, the conductive metal part has the wire width of preferably less than 40 μm, more preferably less than 35 μm, further preferably less than 30 μm or less, and most preferably less than 25 μm. On the other hand, the wire width of at least 1 μm is required on securing conductivity.

In a series of treatment steps including the development step, unevenness in a certain extent generates between the conductive metal part and the light-transmitting part as described before although there is difference in its degree depending on developed hard film action, removal action of a silver salt during fixing, metal deposition in the course of plating, and the like. To reduce the unevenness, the conductive metal part has a thickness of 6 μm or less, and preferably 5 μm or less, but has a thickness of 1 μm or more. Suitable thickness and wire width are selected from securing of conductivity as an electromagnetic shielding film and securing of surface uniformity.

The optically transparent electromagnetic shielding film of the invention has an aperture ratio of preferably 85% or more, more preferably 90% or more, and most preferably 95% or more, from the point of the visible light transmission. The "aperture ratio" used herein means a proportion that a portion not having fine wire forming a mesh occupies in the whole. For example, the aperture ratio of a lattice-shaped mesh of a square having a wire width of 10 μm and a pitch of 200 μm is 90%. [Light-transmitting part]

The "light-transmitting part" used in the invention means a part having transparency, other than the conductive metal part in the electromagnetic shielding film. The light transmission in the light-transmitting part is that transmission expressed by the minimum value of transmission in a wavelength region of from 380 to 780 nm excluding contributory share of light absorption and reflection of the support is 90% ore more, preferably 95% or more, further preferably 97% or more, further more preferably 98% or more, and most preferably 99% or more.

The light-transmitting part in the invention is formed on an unexposed area by subjecting the silver salt-contained layer to exposure and development treatment, together with formation of the metallic silver portion on an exposed area. The light-transmitting part can increase its light transmission property by conducting oxidation treatment after the development treatment, and further after the plating treatment. [Layer constitution of electromagnetic shielding film]

The support in the electromagnetic shielding film of the invention has a thickness of from 5 to 200 μm, and more preferably from 30 to 150 μm. When the thickness is in a range of from 5 to 200 μm, the desired visible light transmission is obtained, and handling is easy.

Thickness of the metallic silver portion provided on the support before plating treatment can appropriately be determined according to the coating thickness of a paint for a silver salt-contained layer applied to the support. The metallic silver portion has the thickness of preferably 30 μm or less, more preferably 20 μm or less, further preferably from 0.01 to 9 μm, and most preferably from 0.05 to 5 μm. The metallic silver portion preferably has a pattern shape.

It is preferable for the conductive metal part to have smaller thickness as the use purpose of an electromagnetic shielding material of a display, because a viewing angle of a display spreads with decreasing the thickness. Further, as the use purpose of a conductive wiring material, small film thickness is required from the demand of high density. From this standpoint, a layer comprising the conductive metal supported on the conductive metal part has a thickness of 6 μm or less, more preferably from 1 to less than 5 μm, and further preferably from 1 to less than 3 μm.

In the invention, the metallic silver portion having the desired thickness can be formed by controlling the coating thickness of the silver salt-contained layer, and thickness of the layer comprising the conductive metal particles can freely be controlled by the plating treatment. Therefore, even the electromagnetic shielding film having a thickness of less than 5 μm, and preferably less than 3 μm, can easily be formed.

It is required in a method using the conventional etching to remove and dispose a large part of the metal thin film by etching. However, in the invention, a pattern containing only the necessary amount of the conductive metal can be provided on the support. Therefore, it is sufficient to use only the necessary minimum amount of a metal, and there is the merit on reduction in production cost and reduction in amount of metal waste. [Functionality added to electromagnetic shielding property]

According to need, the electromagnetic shielding film of the invention is used in combination with a functional layer having functionality other than the electromagnetic shielding property. This functional layer can be made various specifications according to every use purpose. For example, an antireflective layer having an antireflective function imparted thereto, having controlled refractive index and film thickness, a nonglare layer or an antiglare layer (each having scattering-preventive function), a near infrared-absorbing layer comprising a compound or metal, absorbing near infrared light, a layer having color tone controlling function that absorbs visible light of a specific wavelength region, an antifouling layer having a function that is liable to remove stain such as fingerprints, a hard coating layer that is difficult to scratch, a layer having impact-absorbing function, a layer having glass scattering-preventive function when the glass breaks, and the like can be provided as the application of an electromagnetic shielding material for display. Those functional layers may be provided on the face of the support opposite the silver salt-contained layer, or may be provided on the same side.

Those functional films may directly adhered to PDP, or may be adhered to a transparent substrate such as a glass plate or an acrylic resin plate, separately from a plasma display panel body. Those functional films are called an optical filter (or simply a filter).

The antireflective layer having antireflective property imparted thereto suppresses reflection of outside light, thereby suppressing reduction of contrast. Therefore, the antireflective layer is formed by a method of laminating an inorganic substance such as metal oxides, fluorides, suicides, borides, carbides, nitrides or sulfides in a form of a monolayer or a multilayer by a vacuum deposition method, a sputtering method, an ion plating method, an ion beam assist method or the like; a method of laminating a resin having different refractive index, such as an acrylic resin or a fluorine resin, in a form of a monolayer or a multilayer; or the like. Further, a film having antireflective treatment applied thereto can be adhered on the filter. Further, if necessary, a nonglare layer or an antiglare layer can be provided. The nonglare layer and antiglare layer can use, for example, a method of forming a fine powder such as silica, melamine or acryl in a form of an ink, and applying the ink to the surface. The ink can be cured using heat curing or light curing. A nonglare-treated or antiglare-treated film can be adhered on the filter. Further, if necessary, a hard coating layer can be provided.

The near infrared-absorbing layer is a layer containing a near infrared-absorbing dye such as a metal complex compound, or a silver-sputtered layer. The "silver-sputtered layer" used herein means that a dielectric layer and a metal layer are alternately laminated on the support by sputtering or the like. The silver-sputtered layer can cut near infrared light and light of 1,000 nm or more of from far infrared light to electromagnetic wave. The dielectric layer comprises a transparent metal oxide such as indium oxide or zinc oxide, and the metal layer generally comprises silver or silver-palladium alloy. In general, starting from the dielectric layer, three layers, five layers, seven layers or eleven layers are laminated.

The layer having color tone controlling function that absorbs visible light of a specific wavelength region has the characteristic that a fluorescent substance by which PDP emits blue emits red although slightly other than blue. Therefore, there is the problem that a portion to be displayed in blue is displayed with purplish color. As this countermeasure, it is a layer to correct developed color light, and contains a dye that absorbs light in the vicinity of 595 nm.

The electromagnetic shielding film can further provided with a functionality selected from hard coating property, antifouling property, ultraviolet shielding property, gas barrier property and protective property (for example, panel face breakage-preventive property). Examples of such an embodiment include an embodiment in which the above-described functional layer is adhered to the electromagnetic shielding film, and an embodiment in which the above-described functionality is imparted to a constituent layer such as the adhesive layer, the electromagnetic shielding layer or the surface protective layer. An optical filer comprising the support having the electromagnetic shielding film and the functional layer laminated on one side thereof, or laminated on both sides separately is the preferable embodiment of the electromagnetic shielding film of the invention. The optical filter having the electromagnetic shielding function is described hereinafter. [Other constitution elements of conductive electromagnetic shielding film] (1) Adhesive layer

When the electromagnetic shielding film and the conductive film (for example, a transparent electrode) are incorporated in optical filters, liquid crystal display boards, plasma display panels, other image display flat panel, radiographic semiconductor integrated circuits represented by CCD, or the like, those are bonded through an adhesive layer.

The adhesive used in the invention preferably has a refractive index of from 1.40 to 1.70. The reason for this is that in the relationship between the refractive index of the transparent substrate such as a plastic film and that of the adhesive, the difference is minimized, thereby preventing the visible light transmission from decreasing. When the refractive index is in a range of from 1.40 to 1.70, decrease in the visible light transmission is small, which is good.

The adhesive used in the invention is preferably an adhesive that fluidizes by heating or pressuring, and particularly preferably an adhesive showing fluidity by heating at 200°C or lower or by pressurizing to 1 Kgf/cm² or more. By using such an adhesive, the electromagnetic shielding adhesive film of the invention having the conductive layer embedded in a layer of the adhesive can be adhered to a display or plastic plate as an adherent by fluidizing the adhesive layer. Because the adhesive layer can fluidize, the electromagnetic shielding adhesive film can easily be adhered to an adherent, and even an adherent having curved surface or complicated shape, by lamination or pressure molding, particularly pressure molding. From this point, the adhesive preferably has a softening point of 200°C or lower. The electromagnetic shielding adhesive film is generally used under environment at a temperature of less than 80⁰C. Therefore, the adhesive layer has a softening point of preferably 80°C or higher, and most preferably from 80 to 120°C from workability. The softening temperature is a temperature that viscosity is 10¹² poise or less (10¹³ Pa-s or less), and in general, at the temperature, fluidization is observed within a time of from about 1 to 10 seconds.

Representative examples of the adhesive that fiuidizes by heating or pressuring include the following thermoplastic resins. Natural rubbers (refractive index n=1.52); (di)enes such as polyisoprene (n=1.521), poly-l,2-butadiene (n=1.50), polyisobutene (n=1.5.O5 to 1.51), polybutene (n=1.513), poly-2-heptyl- 1,3 -butadiene (n=1.50), poly-2-t-butyl-l,3~ butadiene (n=1.506) and poly- 1,3 -butadiene (n=1.515); polyethers such as polyoxyethylene (n=1.456), polyoxypropylene (n=1.450), polyvinyl ethyl ether (n=1.454), polyvinyl hexyl ether (n=1.459) and polyvinyl butyl ether (n=1.456); polyesters such as polyvinyl acetate (n=1.467) and polyvinyl propionate (n=1.467); polyurethanes (n=1.5 to 1.6); ethyl cellulose (n=1.479); polyvinyl chloride (n=1.54 to 1 55); polyacrylonitriles (n=1.52); polymethacrylonitriles (n=1.52); polysulfones (n=1.633); polysulfides (n=1.6); phenoxy resins (n=1.5 to 1.6); poly(meth)acrylic acid esters such as polyethyl acrylate (n=1.469), polybutyl acrylate (n=1.466), poly-2-ethylhexyl acrylate (n=1.463), poly-t-butyl acrylate (n= 1.464), poly-3-ethoxypropyl acrylate (n=1.465), polyoxycarbonyl tetramethacrylate (n=1.465), polymethyl acrylate (n=1.472 to 1.480), polyisopropyl methacrylate (n=1.473), polydodecyl methacrylate (n= 1.474), polytetradecyl methacrylate (n=1.475), poly-n-propyl methacrylate (n=1.484), poly-3,3,5-trimethylcylcohexyl methacrylate (n=1.484), polyethyl methacrylate (n=1.485), poly-2-nitro-2- methylpropyl methacrylate (n=1.487), poly-l,l-diethylpropyl methacrylate (n=1.489) and polymethyl methacrylate (n=1.489). Those acrylic polymers may be copolymerized in two kinds or more, or may be used as a blend of two kinds or more, according to need.

Copolymer resins of acrylic resins with resins other than the acrylic resins can use epoxy acrylates (n=1.48 to 1.60), urethane acrylates (n=1.5 to 1.6), polyether acrylates (n=1.48 to 1.49), polyester acrylates (n=1.48 to 1.54) and the like. In particular, urethane acrylates, epoxy acrylates and polyether acrylates are excellent from the point of adhesion. Examples of the epoxy acrylates include (meth)acrylic acid adducts such as 1,6-hexanediol diglycidyl ether, neopentylglycol diglycidyl ether, allyl alcohol diglycidyl ether, resolcinol diglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, polyethylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, pentaerythritolpropane triglycidyl ether and sorbitol tetraglycidyl ether. Polymers having a hydroxyl group in the molecule, such as epoxy acryaltes, are effective to improve adhesion. Those copolymer resin can be used as mixtures of two or more thereof, according to need. Those polymers forming the adhesive has a softening point of preferably 200°C or lower, and more preferably 150°C or lower, from handling property. The electromagnetic shielding adhesive film is generally used under environment at a temperature of 80°C or lower. Therefore, the adhesive layer has a softening point of most preferably from 80 to 120°C from workability. On the other hand, it is preferable to use a polymer having a mass average molecular weight (measured using calibration curve of a standard polystyrene by gel permeation chromatography, hereinafter the same) of 500 or more. Where the molecular weight is less than 500, cohesive force of the adhesive composition is too low, so that there is the possibility that adhesion to an adherent decreases. According to need, additives such as diluents, plasticizers, antioxidants, fillers, coloring materials, ultraviolet absorbers and tackifiers may be blended with the adhesive used in the invention. The layer of the adhesive has a thickness of preferably from 10 to 80 μm, and particularly preferably a thickness of the conductive layer or more and from 20 to 50 μm.

The adhesive that covers geometric graphics has difference in refractive index to that of the transparent plastic substrate of 0.14 or less. When the transparent plastic substrate is laminated on the conductive layer through the adhesive, the difference in refractive index between the adhesive layer and the adhesive covering geometric graphics is 0.14 or less. The reason for this is that where refractive index differs between the transparent plastic substrate or between the adhesive and the adhesive layer, visible light transmission decreases. When the difference in refractive index is 0.14 or less, decrease of visible light transmission is small, which is good. Where the transparent plastic substrate is a polyethylene terephthalate (n=1.575; refractive index), examples of the material of the adhesive satisfying the above requirements include epoxy resins (n=1.55 to 1.60) such as bisphenol A epoxy resin, bisphenol F epoxy resin, tetrahdroxyphenyl methane epoxy resin, novolac epoxy resin, resorcin epoxy resin, polyalcohol-polyglycol epoxy resin, polyolefin epoxy resin and alicyclic or halogenated bisphenol. Materials other than the epoxy resin include natural rubbers (n=1.52); (di)enes such as polyisoprene (n=1.521), poly-l,2-butadiene (n=1.50), polyisobutene (n=1.505 to 1.51), polybutene (n=1.5125), poly-2-heptyl-l,3-butadiene (n=1.50), poly-2-t-butyl- 1,3 -butadiene (n=1.506) and poly- 1,3 -butadiene (n=1.515); polyethers such as polyoxyethylene (n=1.4563), polyoxypropylene (n=1.4495), polyvinyl ethyl ether (n=1.454), polyvinyl hexyl ether (n=1.4591) and polyvinyl butyl ether (n=1.4563); polyesters such as polyvinyl acetate (n=1.4665) and polyvinyl propionate (n=1.4665); polyurethanes (n=1.5 to 1.6); ethyl cellulose

polyvinyl chloride (n=1.54 to 1.55); polyacrylonitriles (n=1.52); polymethacrylonitriles (n=1.52); polysulfones (n=1.633); and polysulfides (n=1.6); phenoxy resins (n=1.5 to 1.6). Those exhibit suitable visible light transmission.

On the other hand, where the transparent plastic substrate is an acrylic resin, other than the above-described resins, the following (meth)acrylic acid esters can be used. Polyethyl acrylate (n=1.4685), polybutyl acrylate (n=1.466), poly-2-ethylhexyl acrylate (n=1.463), poly-t-butyl acrylate (n=1.4638), poly-3-ethoxypropyl acrylate (n=1.465), polyoxycarbonyl tetramethacrylate (n=1.465), polymethyl acrylate (n=1.472 to 1.480), polyisopropyl methacrylate (n=1.4728), polydodecyl methacrylate (n=1.474), polytetradecyl methacrylate (n=1.4746), poly-n-propyl methacrylate (n= 1.484), poly-3,3,5-trimethylcylcohexyl methacrylate (n=1.484), polyethyl methacrylate (n=1.485), poly-2-nitro-2-methylpropyl methacrylate (n=1.4868), polytetracarbanyl methacrylate (n=1.4889), poly-l,l-diethylpropyl methacrylate (n=1.4889) and polymethyl methacrylate (n=1.4893). Those acrylic polymers may be copolymerized in two kinds or more, or may be used as a blend of two kinds or more, according to need.

Copolymer resins of acrylic resins with resins other than the acrylic resins can use epoxy acrylates, urethane acrylates, polyether acrylates, polyester acrylates and the like. In particular, epoxy acrylates and polyether acrylates are excellent from the point of adhesion. Examples of the epoxy acrylates include (meth)acrylic acid adducts such as 1,6-hexanediol diglycidyl ether, neopentylglycol diglycidyl ether, allyl alcohol diglycidyl ether, resolcinol diglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, polyethylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, pentaerythritolpropane triglycidyl ether and sorbitol tetraglycidyl ether. The epoxy acrylates have a hydroxyl group in the molecule, and therefore are effective to improve adhesion. Those copolymer resins can be used as mixtures of two or more thereof, according to need. Polymers as the main component of the adhesive have the mass average molecular weight of 1,000 or more. Where the molecular weight is less than 1,000, cohesive force of the adhesive composition is too low, so that adhesion to an adherent decreases.

Examples of a curing agent for the adhesive that can be used include amines such as triethyl tetramine, xylenediamine and diaminodiphenylmethane; acid anhydrides such as phthalic anhydride, maleic anhydride, dodecylsuccinic anhydride, pyromellitic anhydride and benzophenonetetracarboxylic anhydride; diaminodiphenyl sulfone, tris(dimethylammomethyl)phenol, polyamide resins, dicyandiamide and ethyl methyl imidazole. Those may be used alone or as mixtures of two or more thereof. Those cruring agents are added in an amount of from 0.1 to 50 parts by mass, and preferably from 1 to 30 parts by mass, per 100 parts by mass of the above-described polymers. Where the addition amount is less than 0.1 part by mass, curing is insufficient, and where it exceeds 50 parts by mass, crosslinking is excessive, and such may adversely affect adhesion. According to need, additives such as diluents, plasticizers, antioxidants, fillers and tackifiers may be blended with the resin composition of the adhesive used in the invention. The resin composition of the adhesive covers a part or the entire surface of the substrate of the constituent material provided with geometric graphics drawn by a conductive material on the surface of the transparent plastic substrate. Therefore, the resin composition is applied and undergoes solvent drying and heat curing step, thereby forming an adhesive film of the invention. The adhesive film having electromagnetic shielding property and transparency obtained above is used by directly adhering to a display such as CRT, PDP, liquid crystal, EL and the like by the adhesive of the adhesive film, or is adhered to pates or sheets such as acrylic plate or glass plate to thereby the same as a display. Further, the adhesive film is used to window and package for looking in the inside of measurement devices generating electromagnetic wave, measurement instruments and production apparatuses in the similar manner as above. The adhesive film is provided on windows of buildings that may receive radio interference by a tower, high-tension wire or the like, windows of automobiles, and the like. A ground wire is preferably provided to geometric graphics.

The optically transparent part on the transparent plastic substrate has unevenness intentionally to improve adhesion, or transfers the back shape of the conductive material. Therefore, light is scattered on the surface of the optically transparent part, and transparency is impaired. However, when a resin having a refractive index near that of the transparent plastic film is smoothly applied to the uneven surface, irregular reflection is minimized, thereby exhibiting transparency. Geometric graphics drawn by the conductive material on the transparent plastic substrate have very small line width and are not visually recognized. Further, the pitch is sufficiently large, and it is therefore considered to exhibit apparent transparency. On the other hand, the pitch of geometric graphics is sufficiently small as compared with the wavelength of electromagnetic wave to be shielded, and it is therefore considered to exhibit excellent shielding property.

As shown in JP-A-2003-188576, when the electromagnetic shielding film of the invention and other substrate are bonded, a film of an ethylene-vinyl acetate copolymer resin having high heat fusion property, or a heat-fusible resin such as an ionomer resin can be used alone as the transparent substrate film, or when the electromagnetic shielding film of the invention and other resin film are laminated, the lamination can be made without providing an adhesive layer. In general, the lamination is conducted by, for example, a dry lamination method using an adhesive layer. Examples of the adhesive constituting the adhesive layer include an acrylic resin, a polyester resin, a urethane resin, a polyvinyl alcohol resin, a vinyl chloride/vinyl acetate copolymer resin and an ethylene/vinyl acetate copolymer resin. Other than those, thermoplastic resins and ionization radiation curing resins (such as an ultraviolet curing resin and an electron beam curing resin) can be used.

The electromagnetic shielding sheet described in the above publication means a functional group described as "electromagnetic shielding film" in the invention.

In general, the surface of a display is made of a glass. Therefore, a transparent plastic film and a glass plate are bonded using a pressure-sensitive adhesive. When bubbles or peeling generate on the adhered face, there are the problems such that an image distorts, and a display color differs from an original color of the display. The problems of bubble and peeling generate by peeling the pressure-sensitive adhesive from the plastic film or glass plate in nay case. There is the possibility that this phenomenon generates both at the plastic film side and at the glass plate side, and peeling generates at the side of weak adhesion force. Therefore, it is required to have high adhesion force between the pressure-sensitive adhesive and the plastic film or glass plate at high temperature. Specifically, adhesion force between the transparent plastic film and the pressure-sensitive adhesive layer, and between the glass plate and the pressure-sensitive adhesive layer is preferably 10 g/cm, and more preferably 30 g/cm, at 80° C. However, a pressure-sensitive adhesive exceeding 2,000 g/cm may not be preferable because bonding operation becomes difficult, but where such a problem does not occur, such a pressure-sensitive adhesive can be used without problem. Further, it is possible to provide an interleaf (a separator) such that the pressure-sensitive adhesive does not unnecessary contact with other portion in a portion that the pressure-sensitive adhesive does not contact with the transparent plastic film.

The pressure-sensitive adhesive is preferably transparent. Specifically, the pressure-sensitive adhesive has a total light transmission of preferably 70% or more, more preferably 80% or more, and most preferably from 85 to 92%. Further, the pressure-sensitive adhesive preferably has low haze. Specifically, the pressure-sensitive adhesive has a haze of preferably from 0 to 3%, and more preferably from 0 to 1.5%. The pressure-sensitive adhesive used in the invention is preferably colorless so as not to change the inherent display color of a display. However, where thickness of the pressure-sensitive adhesive is small even though the resin itself is colored, it is possible to consider to be substantially colorless. Further, in the case of intentionally conducting coloration as described hereinafter, the above range is not applied similarly.

Examples of the pressure-sensitive adhesive having the above properties include an acrylic resin, an α-olefin resin, a vinyl acetate resin, an acrylic copolymer resin, a urethane resin, an epoxy resin, a vinylidene chloride resin, a vinyl chloride resin, an ethylene-vinyl acetate resin, a polyamide resin and a polyester resin. Of those, an acrylic resin is preferable. Even in the case of using the same resin, it is possible to improve pressure-sensitive adhesive property by a method of reducing the amount of a crosslinking agent added, adding a tackifying material, changing a terminal group of a molecule, or the like when synthesizing the pressure-sensitive adhesive by a polymerization method. Further, even when the pressure-sensitive adhesive is used, it is possible to improve adhesion by surface modifying a face to which the pressure-sensitive adhesive is adhered, that is, a transparent plastic plate or a glass plate. Examples of such a surface modification method include physical methods such as corona discharge treatment and plasma glow treatment, and a method of forming an undercoat layer for improving adhesion.

The pressure-sensitive adhesive preferably has a thickness of from about 5 to 50 μm from the standpoints of transparency, colorless property and handling property. Where the pressure-sensitive adhesive is formed with an adhesive, its thickness is preferably thin within the above range. Specifically, the thickness is from about 1 to 20 μm. However, where a display color of the display itself is not changed and the transparency is within the above range, the thickness may exceed the above range. (2) Peelable protective film

The optical filter according to the invention cam be provided with a peelable protective film.

The protective film may be formed on one side or both sides of the optical filter.

In general, an optical filter is used by further laminating a sheet having effects of reinforcing the outermost surface, imparting antireflective property, imparting antifouling property, and the like on the front and back surfaces of a laminate. Therefore, the protective film is required to peel when conducting such a further lamination. For this reason, lamination of the protective film is desirably conducted peelably.

The protective film has a peel strength of preferably from 5 niN/25 mm width to 5 N/25 mm width, and more preferably from 10 to 100 mN/25 mm width, when laminating on a metal foil. Where the peel strength is less than the lower limit, peeling is excessively easy, and there is the possibility that the protective film peels during handling or by careless contact, which is not preferable. On the other hand, where the peel strength exceeds the upper limit, large force is required to peel, and additionally, when peeling the protective film, there is the possibility that a mesh-like metal foil peels from a transparent substrate film (or an adhesive layer), which is not preferable.

The protective film laminated on the transparent substrate film side is preferably a film that is durable to etching conditions, such as an etchant at about 50°C, particularly a film that is not corroded by its alkali component during immersion for several minutes, or desirably a film that is durable to temperature conditions of about 100°C in the case of dry etching. In the case of laminating a photosensitive resin layer, when the laminate is subjected to dip coating (immersion coating), the coating liquid adheres to an opposite side of the laminate. Therefore, in the case of a step such as coating, the protective film is preferably a film that has adhesion force of the photosensitive resin so as to not cause that the photosensitive resin peels and drifts on the etchant. When an etchant is used, the protective film is preferably a film having durability that is durable to contamination by an etchant containing iron chloride, copper chloride and the like, or durability that is durable to corrosion or contamination by a resist removal liquid such an alkali liquid.

To satisfy the above each point, resin films of polyolefin resins such as a polypropylene resin and a polypropylene resin; polyester resins such as a polyethylene terephthalate resin; polycarbonate resins; acrylic resins and the like are preferably used as a film constituting the protective film. Further, from the above-described standpoints, it is preferable for the protective film that corona discharge treatment is applied to at least a face at the side that becomes the outermost surface when the protective film is applied to a laminate, or an easily-adhesive layer is laminated thereon.

The pressure-sensitive adhesive constituting the protective film can use acrylic acid ester series, rubber series or silicone series pressure-sensitive adhesives.

Materials of the film for the protective film and materials of the pressure-sensitive adhesive described above can be applied to the protective film applied to the metal foil side as they are. Therefore, those protective films may use different films, but it is preferable for those protective films to use the same film.

The electromagnetic shielding film obtained by the production method of the invention has good electromagnetic shielding property and transmission property, and therefore can be used as the optically transparent electromagnetic shielding material. Further, the electromagnetic shielding film can further be used as various conductive wiring materials in circuit wiring and the like. In particular, the electromagnetic shielding film of the invention can suitably be used to display front surface of CRT (cathode ray tube), PDP (plasma display panel), liquid crystal, EL (electroluminescence) and the like, and in a microwave oven, electronic device, a printing wiring board and the like, particularly as an electromagnetic shielding film used in a plasma display panel.

The adhesive layer and the protective layer are described above as constituents of the optically transparent electromagnetic shielding film of the invention, but function as the constituents of the optical filer described hereinafter. [Optical filter]

The optical filter of the invention is a composite functional optical filter comprising a laminate of the electromagnetic shielding film and other functional layer.

Functions possessed by the optical filter are described below.

In general, display screen of a display device is difficult to see by reflection of light fittings. Therefore, the functional film (C) is required to have any of antireflection (AR) property for suppressing reflection of outside light, antiglare (AG) property for prevent reflection of mirror image or antireflection and antiglare (ARAG) property provided with both property. When visible light reflectivity of the surface of a filter for display is low, not only reflection can be prevented, but contract or the like can be improved.

The functional film having antireflection property has an antireflective film, and specifically includes a film in which a thin film of a fluorine series transparent polymer resin, magnesium fluoride, a silicone resin, silicon oxide or the like, having refractive index at a visible light region of 1.5 or less, and preferably 1.4 or less is formed in a form of single layer in an optical film thickness of 1/4 wavelength, and a film in which thin films of an inorganic compound such as a metal oxide, a fluoride, a suicide, a nitride, a sulfide or the like, or an organic compound such as a silicon resin, an acrylic resin, a fluorine resin or the like, each having different refractive index are formed in a form of a multilayer of two ore more layers. However, the invention is not limited to those. Visible light reflectivity of the surface of the functional film (C) having antireflection property is 2% or less, preferably 1.3% or less, and more preferably 0.8% or less.

The functional film having antiglare property has an antiglare film that is transparent to visible light, having fine unevenness surface state of from about 0.1 to 10 μm. Specifically, particles of an inorganic compound or an organic compound, such as silica, an organosilicon compound or an acrylic are dispersed in a thermosetting or photocuring resin such as an acrylic resin, a silicon resin, a melamine resin, melamine resin, a urethane resin, an alkyl resin and a fluorine resin to form an ink, and the resulting ink is applied to a substrate and cured. The particle has an average particle diameter of from 1 to 40 μm. The antiglare property can be obtained by applying the above-described thermosetting or photocuring resin to a substrate, pushing a pattern having the desired gloss value or surface state to the resulting coating, and then curing. However, the invention is not limited to those methods. The functional film having antiglare property has a haze of from 0.5 to 20%, and preferably from 1 to 10%. Where the haze is too small, antiglare property are insufficient, and where the haze is too large, there is the tendency to decrease visibility of a transmitted image.

To add mar resistance to a display filter, it is suitable that the functional film has hard coating property. Examples of the hard coating film include thermosetting or photocuring resins such as an acrylic resin, a silicon resin, a melamine resin, melamine resin, a urethane resin, an alkyl resin and a fluorine resin, but its kind and formation method are not particularly limited. Those films have a thickness of from about 1 to 50 μm. The functional film having hard coating property has a surface hardness of at least H, preferably 2H or more, and more preferably 3H or more, in terms of a pencil hardness according to JIS (K-5400). When antireflective film and/or an antiglare film are formed on the hard coating layer, a functional film having mar resistance, antireflection property and/or antiglare property is obtained, which is suitable.

Dust is liable to adhere to a display filter by static charging. Further, when a human body contacts with the display filter, electric discharge occurs, and the human body may receive electric shock. Thus, there is the case that antistatic treatment is required. Therefore, to impart antistatic ability, the functional film may have conductivity. The conductivity required in this case is sufficient to be about 10¹¹ Ω/square or less in terms of surface resistance. Examples of a method of imparting conductivity include a method of containing an antistatic agent in a film, and a method of forming an antistatic layer. Examples of the antistatic agent include PELESTAT (trade name, a product of Sanyo Chemical Industries, Ltd.) and ELECTROSTRIPPER (a product of Kao Corporation). Examples of the antistatic layer include the conventional transparent conductive film such as ITO, and a conductive film having dispersed conductive ultrafine particles such as ITO ultrafme particles and tin oxide ultrafme particles. It is suitable that the hard coating film, antireflective film and antiglare film have a conductive film, or contain conductive fine particles.

When the surface of the functional film (C) has antifouling property, it is suitable in that stain such as fingerprints can be prevented, and when stain is adhered, such can easily be removed. Materials having antifouling property are materials having non-wettability to water and/or fat and oil, and examples thereof include a fluorine compound and a silicon compound. The fluorine antifouling agent specifically includes OPTOOL (trade name, a product of Daikin Industries, Ltd.). The silicon compound includes TAKATAQUANTUM (trade name, a product of NOF Corporation). When those layers having antifouling property are used as the antireflective film, an antireflective film having antifouling property is obtained, which is suitable.

The functional film preferably has ultraviolet cutting property for the purpose of deterioration and the like of dyes and polymer films described hereinafter. The functional film having ultraviolet protective property is obtained by a method of containing an ultraviolet absorber in the polymer film described after or a method of giving an ultraviolet absorbing film.

Where the display filter is used under environment of temperature and humidity higher than ordinary temperature and ordinary humidity, the dye deteriorates by moisture permeated through the film, moisture coagulates in the pressure-sensitive adhesive used for bonding or at the bonding interface, resulting in fogging, or the tackifier in the pressure-sensitive adhesive generates phase separation with influence by moisture, resulting in fogging. Therefore, it is preferable for the functional film to have gas barrier property. To prevent such dye deterioration or fogging, it is important to prevent impregnation of moisture in a layer containing the dye or a pressure-sensitive adhesive layer. It is suitable that the functional film has a water vapor permeability of 10 g/m²-day or less, and preferably 5 g/m²-day or less.

The polymer film, conductive mesh layer, functional film and if necessary, a transparent molding described hereinafter are bonded through an optional pressure-sensitive adhesive or adhesive that is transparent to visible light. Examples of the pressure-sensitive adhesive or adhesive include an acrylic adhesive, a silicon adhesive, a urethane adhesive, a polyvinyl butyral adhesive (PVB), an ethylene-vinyl acetate adhesive (EVA), a polyvinyl alcohol, a saturated amorphous polyester and a melamine resin. Those may be in a sheet form or a liquid form so long as it has practical adhesion strength. The pressure-sensitive adhesive preferably uses a sheet-like pressure-sensitive adhesive. After adhering the sheet-like pressure-sensitive adhesive or after applying the adhesive, each member is laminated to conduct bonding. The liquid adhesive is an adhesive that cures by allowing the same to stand at room temperature or by heating after bonding. Examples of the application method include bar coating, reverse coating, gravure coating, die coating and roll coating. The application method is selected by considering the kind, viscosity, application amount and the like of the adhesive. Thickness of the coating layer is not particularly limited, but is from 0.5 to 50 μm, and preferably from 1 to 30 μm. It is suitable that the face on which the pressure-sensitive adhesive layer is formed, or the face to be bonded is previously subjected to easy adhesion treatment such as easy adhesion coating or corona discharge treatment, thereby improving wettability. In the invention, the pressure-sensitive adhesive or adhesive that is transparent to visible light is called an optically transparent pressure-sensitive adhesive.

In the invention, when the functional film is bonded to the conductive mesh layer, the optically transparent pressure-sensitive adhesive layer is particularly used. Specific examples of the optically transparent pressure-sensitive adhesive used in the optically transparent pressure-sensitive adhesive layer are the same as described before, but it is important that the thickness is such that depression of the conductive mesh layer can sufficiently be embedded. Where the thickness of the optically transparent pressure-sensitive adhesive layer is smaller than the thickness of the conductive mesh layer, the conductive mesh layer is not sufficiently embedded, so that space is formed and the depression traps air bubbles. As a result, a display filter having turbidity and insufficient optical transparency is formed. On the other hand, where the thickness of the optically transparent pressure-sensitive adhesive layer is too large, there are the problems such that cost for preparing the pressure-sensitive adhesive increases and handling of members becomes bad. When the conductive mesh layer has a thickness of d μm, the thickness of the optically transparent pressure-sensitive layer is preferably from (d-2) to (d+30) μm.

The display filter has a visible light transmission of preferably from 30 to 85%, and more preferably from 35 to 70%. Where the visible light transmission is less that 30%, brightness decreases too much and visibility deteriorates. On the other hand, where the visible light transmission of the display filter is too high, contrast of the display cannot be improved. The visible light transmission in the invention is calculated according to JIS (R-3106) from wavelength dependency of transmission in a visible light region.

When the functional film is bonded to the conductive mesh layer through the optically transparent pressure-sensitive adhesive layer, the depression traps air bubbles, causing fogging, and the optical transparency may be insufficient. In this case, for example where pressure treatment is conducted, gas penetrated in a space between the members when bonding is removed or is solid solubilized in the pressure-sensitive adhesive to remove fogging, thereby improving optical transparency. The pressure treatment may be conducted in the state of the above constitution or in the state of the display filter of the invention.

Examples of the pressure treatment include a method of sandwiching a laminate between flat plates and pressing, a method of passing a laminate through nip rolls, and a method of introducing a laminate in a pressure vessel and pressuring. However, the pressure treatment is not particularly limited. The method of pressuring a laminate in a pressure vessel is suitable in that pressure is uniformly applied to the whole of the laminate, thus being free from uneven pressurization, and plural laminates can be treated at a time. The pressure vessel can use an autoclave.

The pressurizing conditions are that air bubbles bitten can be lost and treatment time can be shortened as pressure increases. However, the pressure is from about 0.2 to 2 MPa, and preferably from 0.4 to 1.3 MPa, from the limitations on pressure resistance of a laminate and an apparatus used in a pressuring method. The pressuring time varies depending on the pressuring conditions, and is not particularly limited. However, where the pressuring time is too long, the treatment time increases, resulting in increase of cost. Therefore, the holding time is preferably 6 hours or less under appropriate pressuring conditions. In particularly, in the case of a pressure vessel, it is suitable to hold the laminate for about from 10 minutes to 3 hours after reaching the setting pressure.

There is the case that it is preferable to conduct heating simultaneously when pressuring. By conducting heating, fluidity of the optically transparent pressure-sensitive adhesive decreases temporarily. As a result, air bubbles bitten are liable to be removed or air bubbles are liable to be solid solubilized in the pressure-sensitive adhesive. The heating condition is from room temperature to about 80°C from heat resistance of each member constituting a display filter, but is not particularly limited.

The pressure treatment or the pressure heating treatment can suitably improve adhesion force after bonding between the respective members constituting a display filter.

The display filter of the invention is provided with the optically transparent pressure-sensitive adhesive layer on the other main surface of the polymer film on which the conductive mesh layer is not formed. Specific examples of the optically transparent pressure-sensitive adhesive used in the optically transparent pressure-sensitive adhesive layer are as described before, and are not particularly limited. The thickness is not particularly limited, but is from 0.5 to 50 μm, and preferably from 1 to 30 μm. It is suitable to previously apply an easy adhesion treatment such as easy adhesion treatment or corona discharge treatment to the face on which the optically transparent pressure-sensitive adhesive layer or the face to be bonded, thereby improving wettability.

A release film may be formed on the optically transparent pressure-sensitive adhesive layer. Such an embodiment has a constitution of at least functional film/ optically transparent pressure-sensitive adhesive layer/conductive mesh layer/polymer film/( optically transparent pressure-sensitive adhesive layer)/release film. The release film is formed by applying a silicone or the like to the main surface of the polymer film contacting with the pressure-sensitive adhesive layer. When the display filter of the invention is bonded to the main surface of an optically transparent molding described hereinafter, or bonded to the surface of a display, for example, a front glass of a plasma display panel, the display filter is bonded after peeling the release film and exposing the optically transparent pressure-sensitive adhesive layer.

The display filter of the invention is mainly used for the purpose of shielding electromagnetic wave emitted from various plasma displays. Preferable example of the display filter is a plasma display filter.

As described before, the plasma display emits near infrared light with high intensity, and therefore, the display filter of the invention is required to cut not only electromagnetic wave but near infrared light to a level free from practical problem. The transmission in a wavelength region of from 800 to 1,000 nm is required to be 25% or less, preferably 15% or less, and more preferably 10% or less. Further, the plasma display filter used in a plasma display is required that its transmitting color is neutral gray or bluish gray. The reason for this is that it is necessary to maintain or improve light emission characteristics and contrast of a plasma display, and there is the case that white having color temperature slightly higher than that of a standard white is preferred. Further, it is said that a color plasma display is insufficient in its color reproducibility, and it is preferable to selectively reduce unnecessary light emission from a fluorescence substance or a discharged gas, which is a cause of the insufficient color reproducibility. In particular, emission spectrum of red display shows several emission peaks over a wavelength of from about 580 to 700 nm, and there is the problem that red emission becomes emission having poor color purity near orange by emission peak at a relatively strong short wavelength side. Those optical property can be controlled by using a dye. That is, a near infrared absorbing agent is used to cut near infrared light, a dye that selectively absorbing unnecessary emission can be used to reduce unnecessary emission, thereby achieving the desired optical property, and color tone of the display filter can be made suitable color tone by using a dye having an appropriate absorption in a visible light region.

A method of containing a dye is selected from at least one of (1) a polymer film or resin plate having at least one of dyes mixed with a transparent resin, (2) a polymer film or resin plate prepared by dispersion dissolving at least one dye in a resin concentrated liquid of a resin or resin monomer/organic solvent, and using a casting method, (3) a coated polymer film or resin plate obtained by adding at least one dye to a resin binder and an organic solvent to prepare a paint and applying the paint to a polymer film or resin plate, and (4) a transparent pressure-sensitive adhesive containing at least one dye. However, the method is not limited to those. The term "containing" used herein means the state that a dye is contained in the inside of a substrate, a layer such as a coating film, or a pressure-sensitive adhesive, and also the state that a dye-containing liquid is applied to the surface of a substrate or a layer.

The above-described dyes are general dyestuffs, pigments or near infrared absorbers, having the desired absorption wavelength in a visible light region, and its kind is not particularly limited, and the examples thereof include commercially available organic dyestuffs such as anthraquinone series, phthalocyanine series, methane series, azomethine series, oxazine series, imonium series, azo series, styryl series, coumarin series, porphyrin series, dibenzofuranone series, diketopyrrolopyrrole series, rhodamine series, xanthene series, pyrromethene series, dithiol series, and diiminium series compounds. Its kind and concentration are determined by absorption wavelength and absorption coefficient, transmission characteristics and transmission required in a display filter, and kind and thickness of a medium dispersed or a coating film, and are not particularly limited.

The plasma display panel has high panel surface temperature, and when the environmental temperature is high, the temperature of the display panel particularly elevates. Therefore, it is suitable that the dye has heat resistance that, for example, does not remarkably deteriorate by decomposition or the like at 80°C. In addition to heat resistance, light resistance may be poor depending on the dye. Where deterioration by light emission of a plasma display or ultraviolet light or infrared light as the outside light becomes problem, it is important to use a member containing an ultraviolet absorber or a member that does not transmit ultraviolet light, thereby reducing deterioration of a dye by ultraviolet light, and to use a dye that does not involve remarkable deterioration by ultraviolet light or visible light. In the environment of humidity in addition to heat and light, and their combinations, the same is applied. When the dye deteriorates, transmission characteristics of a display filter change, and color tome changes or near infrared cutting ability deteriorates. Additionally, because the dye is dispersed in a medium or a coating film, solubility and dispersibility to an appropriate solvent is important. In the invention, at least two dyes having different absorption wavelength may be contained in one medium or coating film, or at least two media or coating films, containing the dye may be used.

In the invention, the above methods (1) to (4) containing the dye can be used in the display filter of the invention with at least one embodiment of (A) a polymer film containing a dye, (C) a functional film containing a dye, (Dl) an optically transparent pressure-sensitive adhesive containing a dye, and (D2) an optically transparent pressure-sensitive adhesive. In general, a dye is liable to deteriorate. Ultraviolet light that a display filter receives under general use conditions is included in the outside light such as solar light. Therefore, to prevent deterioration of the dye by ultraviolet light, it is preferred that at least one layer selected from the layer itself containing a dye and a layer at the side of a person who receives the outside light than the dye-containing layer has a layer having ultraviolet cutting ability. For example, where the polymer film (A) contains a dye, when the optically transparent pressure-sensitive adhesive and/or functional film contain an ultraviolet absorber or have a functional film having an ultraviolet cutting ability, the dye can be protected from ultraviolet light included in the outside light. The ultraviolet cutting ability necessary to protect the dye is that the transmission in an ultraviolet light region shorter than a wavelength of 380 nm is 20% or less, preferably 10% or less, and more preferably 5% or less. The functional film having the ultraviolet cutting ability may be a coating film containing an ultraviolet absorber or an inorganic film that reflects or absorbs ultraviolet light. The ultraviolet absorber can use the conventional compounds such as benzotriazole series and benzophenone series compounds. Its kind and concentration are determined from dispersibility and dissolution of the ultraviolet absorber dispersed or dissolved in a medium, absorption wavelength and absorption coefficient, thickness of a medium, and the like, and are not particularly limited. It is preferable that the layer or film having ultraviolet cutting ability has small absorption in a visible light region, does not involve remarkable decrease of a visible light transmission, and does not show color such as yellow. In the functional film containing a dye, when a layer containing a dye is formed, it is only necessary that a film at the person side than the layer or the functional film has the ultraviolet cutting ability, and when the polymer film contains the dye, it is only necessary that a functional film or functional layer having the ultraviolet cutting ability is present at the person side than the polymer film.

There is the case that a dye deteriorates by contact with a metal. Where such a dye is used, it is further preferable that the dye is arranged so as not to contact with the conductive mesh layer as possible. Specifically, it is preferable that the dye-containing layer is the functional film, the polymer film or the optically transparent pressure-sensitive adhesive layer, and it is particularly preferable that the dye-containing layer is the optically transparent pressure-sensitive adhesive layer.

The display filter of the invention is that the polymer film (A), the conductive mesh layer (B), the functional film (C), the optically transparent pressure-sensitive adhesive layer (Dl) and the optically transparent pressure-sensitive adhesive layer (D2) are constituted in the order of (C)/(D1)/(B)/(A)/(D2), and is preferably that the conductive mesh layer comprising the conductive mesh layer (B) and the polymer (A), and the functional film are bonded with the optically transparent pressure-sensitive adhesive layer (Dl), and the optically transparent pressure-sensitive adhesive layer (D2) is provided on the main face of the polymer film (A) opposite conductive mesh layer (B).

When the display filter of the invention is mounted on a display, it is mounted such that the functional film (C) is at the person side and the optically transparent pressure-sensitive adhesive layer (D2) is at the display side.

A method of providing the display filter of the invention on the front surface of the display and using the same includes a method of using the same as a front surface filter plate having a transparent molding (E) described hereinafter as a support, and a method of using by bonding the same to the display surface through the optically transparent pressure-sensitive adhesive layer (D2). In the former, arrangement of the display filter is relatively easy, and mechanical strength is improved by the support. This is suitable for protection of a plasma display. In the latter, because of not using a support, light weight and thinning are possible, and reflection of the display surface can be prevented, which is suitable.

The transparent molding includes a glass plate and an optically transparent plastic plate. The plastic plate is preferable from mechanical strength, lightweight and breakage resistance. However, the glass plate can also be used from thermal stability of less heat distortion. Specific examples of the plastic plate that can be used include an acrylic resin such as polymethyl methacrylate (PMMA), a polycarbonate resin, and a transparent ABS resin. However, the invention is not limited to those. In particular, PMMA is suitably used from high transparency at a wide wavelength region and high mechanical strength. Thickness of the plastic plate is only necessary that sufficient mechanical strength and rigidity that does not distort and maintains flatness are obtained, and is not particularly limited. The thickness is generally from about 1 to 10 mm. The glass is preferably a semi-tempered glass plate or a tempered glass plate having been subjected to chemical tempering or air-cooling tempering for imparting mechanical strength. Considering a mass, thickness of the glass plate is preferably from about 1 to 4 mm, but is not particularly limited. The transparent molding can be subjected to necessary various conventional pretreatments before bonding a film, and color (such as black) frame printing may be applied to a portion becoming a margin of a display filter.

The constitution of the display filter in the case of using the transparent molding is at least functional film (C)/optically transparent pressure-sensitive adhesive layer (Dl)/conductive mesh layer (B)/polymer film (A)/ optically transparent pressure-sensitive adhesive layer (D2)/transparent molding (E). The functional film (C) may be provided on the main surface of the transparent molding (E) opposite the face thereof having the optically transparent pressure-sensitive adhesive layer (D2) bonded thereto, through an optically transparent pressure-sensitive adhesive layer. In this case, it is not necessary to have the same function and constitution as the functional film (C) provided at an observer side. For example, in the case of having antireflectivity, back reflection of a display filter having a support can be reduced. Similarly, a functional film (C2) such as an antireflective film may be formed on the main surface of the transparent molding (E) opposite the surface thereof having the optically transparent pressure-sensitive adhesive layer (D2) bonded thereto. In this case, the functional film (C2) can be provided on a display at a person side. However, as described before, it is preferable to provide a layer having ultraviolet cutting ability on the dye-containing layer and a layer at a person side than the dye-containing layer.

Further, the optical filter of the invention can employ the embodiment that the surface of the conductive metal part and the visible light transmitting part of the conductive electromagnetic shielding film is arranged outermost. (Current-carrying part)

A device requiring electromagnetic shielding requires to shield electromagnetic wave by proving a metal layer in the inside of a case the device or by using a conductive material to the case. Where a display portion requires transparency as in a display, a window-shaped electromagnetic shielding filter having an optically transparent conductive layer is provided as in the display filter of the invention. Electromagnetic wave is absorbed in a conductive layer, and then induces charge. Therefore, unless charge is escaped by grounding, the display filter again functions as an antenna to oscillate electromagnetic wave, thereby electromagnetic shielding ability deteriorates. For this reason, the display filter and a grounding portion of a display main body are required to be electrically contacted. To achieve this, the optically transparent pressure-sensitive adhesive layer (Dl) and the functional film (C) are required to be formed on the conductive mesh layer (B) while remaining a conducting portion that can electrically conducts from the outside. Shape of the conducting portion is not particularly limited, but it is important that a space that leaks electromagnetic wave is not present the display filter and the display main body. Therefore, it is preferred that the conducting portion is continuously provided on a margin of the conductive mesh layer (B). That is, it is preferable that the conducting portion is provided in a frame shape, excluding a central portion as a display portion of a display.

The conducting portion is required to be not patterned even though it is the same layer as the conductive mesh pattern layer, and is preferably a conducting portion that is not patterned as a metal foil solid layer in order to facilitate electrical contact between the display main body and the grounding portion.

Where the conducting portion is not patterned as a metal foil solid layer and/or the conducting portion has sufficiently strong mechanical strength, the conducting portion can be used as an electrode as is, and this is preferable.

To protect the conducting portion and/or to facilitate electrical contact to the grounding portion where the conducting portion is a mesh pattern layer, there is the case to be preferable to form an electrode on the conducting portion.

From the points of conductivity, contact resistance, adhesion to a transparent conductive film, and the like, examples of the material used in the electrode include silver, copper, nickel, aluminum, chromium, iron, zinc, carbon and alloys comprising at least two of those; and pastes comprising mixtures of a borosilicate glass and each material or alloys of the above materials. Printing and coating of the paste can use the conventional methods. Further, the commercially available conductive tapes can also be suitably used. The conductive tape has conductivity on both surfaces, and a one-sided adhesive tape using a conductive adhesive of carbon dispersion and a double-sided adhesive tape can preferably be used. Thickness of the electrode is not particularly limited, but is from several μm to several mm.

According to the invention, its image quality can be maintained or improved without remarkably impairing brightness of a plasma display. The invention can obtain a display filter that has excellent electromagnetic shielding ability that shields electromagnetic wave which is pointed out the possibility of harming health, emitted from a plasma display, and that does not adversely affect wavelength used in remote controllers of peripheral electronic devices, transmitting optical communication, and the like and can prevent malfunction. The invention can further provide a display filter having excellent weather resistance at low cost.

Embodiment

The characteristics of the invention are further specifically described by referring to the following Examples and Comparative Examples. Materials, use amounts, proportions, treatment contents, treatment procedures and the like can appropriately be changed as far as the gist of the invention is not deviated. Therefore, the scope of the invention should not be interpreted in a limited manner by the specific examples shown below. (Example 1)

1. Preparation of silver halide photosensitive material sample Preparation of support

Undercoat first layer and second layer having the following compositions were applied to both surfaces of a biaxially stretched polyethylene terephthalate support (thickness: 100 μm).

Undercoat first layer

Core-cell vinylidene chloride copolymer (1) 15 g

2,4-Dichloro-6-hydroxy-s-triazine 0.25 g

Polystyrene fine particles 0.05 g

(average particle diameter: 3 μm)

Compound (Cpd-20) 0.20 g

Colloidal silica 0.12 g

(SNOWTEX ZL: particle diameter 70-100 μm, a product of Nissan Chemical Industries, Ltd.)

To add water so that total mass become 100 g

Further, a coating liquid prepared by adding 10 mass% of KOH to adjust pH=6 was applied at a drying temperature of 180°C for 2 minutes such that a dry thickness is 0.9 μm.

Undercoat second layer

Gelatin 1 g

Methyl cellulose 0.05 g

Compound (Cpd-21) 0.02 g

Ci₂H₂₅O(CH₂CH₂O)_I0H 0.03 g

Proxel 3.5xlO^"3 g

Acetic acid 0.2 g

To add water 100 g

This coating liquid was applied at a drying temperature of 17O⁰C for 2 minutes such that a dry thickness is 0.1 μm. Core-shell v±nylidene chloride copolymer ( 1 )

Core: VDC/MMA/MA (80 wt%) Shell: VDC/AN/AA (20 wt%) Average particle size: 70 niα

Compound (Cpd-20)

Compound (Cpd-21 )

Preparation of emulsion A

Liquid 1

Water 750 ml

Gelatin 2O g

Sodium chloride 1.6 g

1 ,3 -Dimethylimodazoline-2-thione 20 mg

Sodium benzenethiosulfonate 10 mg Citric acid 0.7 g

Liquid 2

Water 300 ml

Silver nitrate 150 g

Liquid 3

Water 300 ml

Sodium chloride 38 g

Potassium iodide 32 g

Potassium hexachloroiridate (III) 38 g

(0.005% KCl, 20% aqueous solution)

Ammonium hexachlororhodate 7 ml

(0.001% NaCl, 20% aqueous solution)

Potassium hexachloroiridate (HI) (0.005% KCl, 20% aqueous solution) and ammonium hexachlororhodate (0.001% NaCl, 20% aqueous solution) used in the liquid 3 were prepared by dissolving the respective powder in the respective KCl 20% aqueous solution and NaCl 20% aqueous solution and heating at 40⁰C for 120 minutes.

The liquid 2 and the liquid 3 in the respective amount corresponding to 90% of each entire amount were simultaneously added to the liquid 1 maintained at38°C and pH 4.5 over 20 minutes while stirring to form nucleus particles of 0.15 μm. Subsequently, the following liquid 4 and liquid 5 were added over 8 minutes, and the respective remaining 10% amount of the liquid 2 and the liquid 3 were added over 2 minutes to grow the particles to particles of 0.18 μm. Further, 0.15 g of potassium iodide was added and aged to complete particle formation. Liquid 4

Water 100 ml Silver nitrate 50 g

Liquid 5

Water 100 ml

Sodium chloride 13 g

Potassium iodide H g

Yellow prussiate of potash 5 mg

Thereafter, water washing was conducted by a flocculation method according to the conventional method. Specifically, temperature was lowered to 35°C, 3 g of an anionic precipitating medium- 1 was added, and pH was lowered using sulfuric acid until precipitating silver halide (pH was in a range of 3.2+0.2). About 3 liters of a supernatant was removed (first water washing). 3 liters of distilled water was added and sulfuric acid was then added until precipitating silver halide. Again, 3 liters of the supernatant was removed (second water washing). The same operation as the second water washing was repeated one time (third water washing) to complete water washing/desalination steps. 8 g of gelatin was added to an emulsion after water washing and desalination to adjust pH to 5.6 and pAg to 7.5. 10 mg of sodium benzenethiosulfonate, 3 mg of sodium benzenethiosulinate, 15 mg of sodium thiosulfate and 10 mg of chloroauric acid were added, chemical sensitization was applied so as to obtain the optimal sensitivity at 55°C, and 100 mg of l,3,3a,7-tetraazaindene as a stabilizer and 100 mg Proxel (trade name, a product of ICI Co., Ltd.) as a preservative were added. Finally, a silver iodochlorobromide cubic particle emulsion containing 70 mol% of silver chloride and 0.08 mol% of silver iodide and having an average particle diameter of 0.18 μm and a variation coefficient of 9% was obtained (as a final emulsion, pH=5.7, pAg=7.5, conductivity=60 μS/m, density=1.28xlθ³ kg/m³ and viscosity=60 mPa-s). Anionic precipitating medium-1

Average molecular weight : 120 , 000

Emulsion layer

5.7xlO^"4 mol/mol Ag of a sensitizing dye (SD-I) was added to the emulsion A, followed by applying spectral sensitization. 3.4x10^"4 mol/mol Ag of KBr and 8.OxIO^"4 mol/mol Ag of the compound (Cpd-3) were further added, followed by well mixing.

1.2xlO^'4 mol/mol Ag of l,3,3a,7-tetraazaindene, 1.2xlO^"4 mol/mol Ag of hydroquinone, 3.OxIO^"4 mol/mol Ag of citric acid and surfactant (Sa-I), (Sa-2) or (Sa-3) were added such that each coating amount is 60 mg/m², 40 mg/m² and 2 mg/m², and pH of the coating liquid was adjusted to 5.6. The emulsion layer coating liquid thus prepared was applied to the following support such that Ag is 7.6 g/m² and gelatin is 1.1 g/m². UL layer

Gelatin 0.23 g/m²

Compound (Cpd-7) 40 mg/m²

Compound (Cpd- 14) 10 mg/m²

Preservative (Proxel) 1.5 mg/m²

Viscosity of the coating liquid of each layer was adjusted by adding a thickener represented by the following structure (Z). Thickener Z

The sample used in the invention formed a back layer and antistatic layer, having the following compositions.

Back layer

Gelatin 3.3 g/m²

Compound (Cpd-15) 40 mg/m²

Compound (Cpd-16) 20 mg/m²

Compound (Cpd-17) 90 mg/m²

Compound (Cpd-lS) 40 mg/m²

Compound (Cpd-19) 26 mg/m²

1 , 3 -Diviny lsulfonyl-2-propanol 60 mg/m²

Polymethyl methacrylate fine particle 30 mg/m²

(average particle diameter: 6.5 μm)

Liquid paraffin 78 mg/m²

Compound (Cpd-7) 120 mg/m²

Calcium nitrate 20 mg/m²

Preservative (Proxel) 12 mg/m²

Antistatic layer

Gelatin 0.1 g/m²

Sodium dodecylbenzene sulfonate 20 mg/m²

Coating method

UL layer and emulsion layer were simultaneously applied to the support having the undercoat layer applied thereto in the order of the UL layer and the emulsion layer from the side near the support as the emulsion face side by a slide bead coater method while maintaining at 35°C, and the resulting laminate was passed through a cold air set zone (5°C). Cpd-7 as a hardener was added in the amount described before to the UL layer just before application, and diffused from the UL layer to contain in the emulsion layer. Antistatic layer and back layer were simultaneously applied to the side of the support opposite the emulsion face in the order of the antistatic layer and the back layer from the side near the support by a curtain coater method while adding a hardener liquid, and the resulting laminate was passed through a cold air set zone (5°C). At the time that the laminate passed through each set zone, the coating liquid showed sufficient setting property. Subsequently, both surfaces were simultaneously dried with drying zone. Thus, a sample (1-1) was prepared.

2. Exposure of sample and treatment condition (Exposure)

A sample 101 photographic material was irradiated with laser slit light through a lattice-shaped photomask (a photomask having line/space=290 μm/10 μm (pitch 300 μm) and a lattice-shaped space) capable of giving a developed silver image of line/space=10 μm/290 μm to an emulsion layer coating film of a roll-shaped sample (1-1) having a length of 150 m and a width of 67 cm to conduct mesh pattern exposure. Using an electromagnetic shielding film production apparatus of a series of web transport system, having incorporated therein feed of a film, an exposed part, a development treatment part, a plating treatment part, a blackening treatment part and drying part, a long rolled film fed from a delivery roller of a photosensitive material is carried while winding along a circumference of the exposure roller in semicircular length. A light-receiving portion is provided close to nearly a central portion of the semicircle. A laser light source is provided on the upper portion of the photomask in a direction of its roller diameter. Pattern exposure is conducted by a slit light emitted from a laser light source through a photomask on the circumference of the exposure roller while continuously feeding the long rolled film on the exposure roller. The photomask forms the desired mesh pattern and plural mesh patterns relating to negatives on the plate. (Development treatment)

A running treatment (until that the cumulative replenishment amount is three times its tank volume) was applied to a sample after exposure using treatment steps and each sample shown below.

1) Conductive film 101 sample Ag: A conductive film having a conductive metal part comprising a developed silver was prepared by applying the following development treatment.

2) Conductive film 101 sample Cu: A conductive film having a conductive metal part comprising a developed silver and copper was prepared by applying the following development treatment and the subsequent plating treatment.

The development treatment was conducted using a developer (A) and a developer (B) having the following formulations with an automatic processor FG-860AG (a product of Fuji Photo Film Co.) under development conditions of 30°C and 30 seconds. Developer (A) formulation (showing components per 1 liter of a concentrated liquid)

Potassium hydroxide 60.0 g Diethylenetriamine-pentaacetate 3.O g

Potassium carbonate 90.O g

Sodium metabisulfite 105.0 g

Potassium iodide 10.5 g

Hydroquinone 60.O g

5-Methylbenzotriazole 0.53 g

4-Hydroxymethyl-4-methyl-lphenyl-pyrazolidone 2.3 g

Sodium 3-(5-mercaptotetrazol-l-yl)benzenesulfonate 0.15 g

Sodium 2-mercaptobenzimidazole-5-sulfonate 0.45 g

Sodium erythorbinate 9.O g

Diethylene glycol 7.5 g pH 10.79 In using, a mother liquor was diluted in the proportion of 1 part of water to 2 parts of the above concentrated liquid, pH of the mother liquor was 10.65, the replenisher was diluted in the proportion of 3 parts of water to 4 parts of the above concentrated liquid, and pH of the replenisher was 10.62.

Fixing solution (B) formulation (showing the formulation per 1 liter of a concentrated liquid)

Ammonium thiosulfate 36O g

Ethylene diamine-tetraacetate-2Na-dihydrate 0.09 g

Sodium thiosulfate-pentahydrate 33.0 g

Sodium metasulfite 57.0 g

Sodium hydroxide 37.2 g

Acetic acid (100%) 8.7 g

Sodium gluconate 5.1 g Aluminum sulfate 25.2 g

Potassium iodide 6.3 g pH 5.85

In using, it is diluted in the proportion of 2 parts of water to 1 part of the above concentrated liquid. pH of the liquid used is 4.8. The replenisher uses the diluted liquid as same as the above liquid used, and replenishment was conducted in an amount of 258 ml per 1 m² of the photosensitive material. Development treatment Treatment step Temperature Time

Black-and-white development 30°C 20 seconds

Fixing 35°C 20 seconds

Waster washing* 1 35°C 60 seconds

Drying 50°C 60 seconds

(Plating treatment)

Plating treatment was applied to the film having a silver mesh pattern formed by the above treatment using an electrolytic plating apparatus equipped with an electrolytic plating bath 10 shown in Fig. 1. The photosensitive material was fitted on the electrolytic apparatus such that its silver mesh face faces downward (the silver mesh face is contacted with a feed roller).

A roller comprising a mirror-finished stainless steel roller (10 cm diameter, 70 cm length) having a 0.1 mm thick electric copper plating formed on the surface thereof was used as the feed rollers 12a and 12b. A roller having 5 cm diameter and 7 cm length without copper plating was used as the guide roller 14 and other transport rollers. Height of the guide roller 14 was controlled so as to secure a constant treatment time in liquid even though a line speed differs.

Distance (distance La shown in Fig.l) between the undermost part of the face contacting the feed roller 12a at the inlet side and the silver mesh face of the film, and the plating liquid level was 5 cm. Distance (distance Lb shown in Fig. 1) between the undermost part of the face contacting the feed roller at the outlet side and the silver mesh part of the photosensitive material, and the plating liquid level was 10 cm.

Line speed of the plating apparatus was 2.5 m/min.

Acid washing 35°C 20 seconds Water washing 3 Electrolytic plating 1 35° C 20 seconds voltage 15V Electrolytic plating 2 35° C 20 seconds voltage 14V Electrolytic plating 3 35° C 20 seconds voltage 13 V Electrolytic plating 4 35° C 20 seconds voltage 12V Electrolytic plating 5 35° C 20 seconds voltage 10V Electrolytic plating 6 35° C 60 seconds voltage 8V Electrolytic plating 7 35° C 60 seconds voltage 7V Electrolytic plating 8 35° C 60 seconds voltage 6V Electrolytic plating 9 35° C 60 seconds voltage 5V Electrolytic plating 10 35° C 60 seconds voltage 4V Water washing 4* 35° C 30 seconds Water washing 5* 25° C 30 seconds Blackening treatment 50° C 120 seconds voltage 4V Water washing 6 25° C 60 seconds voltage 4V Antirust liquid 25° C 30 seconds Water washing 7 25° C 60 seconds Drying 50°C 60 seconds

*: Water washing process was two tank countercurrent flow system of from 2 to 1 and

5 to 4. The above water washing steps all used well water, and flow rate was 5 liters/min.

By applying the above exposure, development and plating treatment to each sample, an optically transparent conductive film comprising a metal fine wire part and a light transmitting part substantially free of a metal was formed. The metal fine wire part shows a mesh-shaped pattern according to exposure pattern, and line/space width was 10 μm/290 μm in any samples. Further, aperture ratio of the light-transmitting part was about 90% in any samples. Comparative Example

An etching-processed mesh film utilizing a photolithography was prepared as the conventional optically transparent electromagnetic shielding material formed by patterning a visible light-transmitting part and a conductive metal part, according to the preparation method of a metal mesh described in JP- A-2003 -46293. Haze measurement

Haze of a film was measured using a haze meter MODEL 100 IDP (a product of Nippon Denshoku Industries Co., Ltd.). Each haze value was that the conductive film sample 101 Ag of the invention is 2.8%, the conductive film sample 101 Cu of the invention is 3.2%, and the etching-processed mesh film sample of the Comparative Example is 12.5%. Image sharpness organoleptic evaluation

As a practical evaluation method of haze, sharpness evaluation of image of the film obtained was conducted by an image diffusion organoleptic examination by ten panelists. The organoleptic evaluation method was conducted as follows. Each electromagnetic shielding film was arranged by closely contacting with PDP display panel or by floating 5 mm from the panel. A group of buildings, flower garden, human faces, spread sheets of table calculation software and the like displayed on the display panel are observed for 30 seconds, and image diffusion rating was conducted. The rating was as follows. Image comparable to the image without filter was rated 4 points, image that does not feel diffusion was rated 3 points, image that feels diffusion but is allowable was rated 2 points, and image that is not allowable was rated 1 point. Average value often panelists was obtained. The results obtained are shown in Table 1 below.

As shown in Table 1, it is seen that the conductive film of the invention does not feel image diffusion in close contact sample observation and floating sample observation, but the etching-processed mesh film of the Comparative Example cannot almost be allowable. [Example 2]

The conductive film sample 101 Cu after plating prepared in Example 1 was further treated with a copper blackening treatment liquid to blacken a cupper surface. Thus, a conductive film sample 101 BK was obtained. The commercially available copper black (a product of Isolate Chemical Research Institute) was used as the blackening treatment liquid. A protective film having a total thickness of 28 μm (a product of Panac Industries, Inc., part number: HT-25) was bonded to the PET face side of the conductive film using a laminator roller.

A protective film having a total thickness of 65 μm, having an acrylic pressure-sensitive adhesive layer laminated on a polyethylene film (a product of Sun A. Kaken Co., Ltd., trade name: Sanitect Y-26F) was bonded to the electromagnetic shielding film (metal mesh) side using a laminator roller.

The resulting laminate was bonded to a glass plate having a thickness of 2.5 mm and a outside dimension of 950 mm x 550 mm through a transparent acrylic pressure-sensitive adhesive such that the PET side is a bonding face.

An antireflective near infrared light absorption film (a product of Sumitomo Osaka Cement, trade name: Clearance AR/NIR) comprising a 100 μm thick PET film, an antireflective layer and a near infrared absorber-containing layer was bonded to the opposite side of the glass through a 25 μm thick acrylic optically transparent pressure-sensitive adhesive. Toning dyes (products of Mitsui Chemicals, Inc., PS-Red-G and PS-Violet-RC) that adjust permeation characteristics of a display filter were contained in the acrylic optically transparent pressure-sensitive adhesive layer. An antireflective film (a product of NOF Corporation, trade name: REALOOK 8201) was bonded through a pressure-sensitive adhesive to prepare a display filter.

As an alternative laminating order, an infrared absorption face of an infrared absorbing film was bonded to a PET face of the conductive film 101 BK through a transparent acrylic pressure-sensitive adhesive, and a face opposite the infrared absorption face of the infrared absorbing film was bonded to a glass plate having a thickness of 2.5 mm and an outside dimension of 950 mm x 550 mm through a transparent acrylic pressure-sensitive adhesive. Toning dyes (products of Mitsui Chemicals, Inc., PS-Red-G and PS-Violet-RC) that adjust permeation characteristics of a display filter were contained in the acrylic optically transparent pressure-sensitive adhesive layer. An antireflective film (a product of NOF Corporation, trade name: REALOOK 8201) was bonded through a pressure-sensitive adhesive to prepare a display filter.

The display filter obtained had very low scratches and mesh defects. Further, the metal mesh had black color, and display image did not develop metallic color. Additionally, the display filter had electromagnetic shielding ability and near infrared cutting ability (transmission at 300 to 800 nm is 15% or less) free from practical problem, and showed excellent visibility even though an antireflective film generally present is not present on the conductive film. Further, by containing the dye, toning function can be imparted, and such a display filter can suitably be used as a display filter of plasma display and the like.

Industrial Applicability

The conductive film of the invention characterized in that specific fine wire width and fine wire thickness are adjusted by applying pattern exposure and development to a silver salt photosensitive material, and a mesh layer surface is smoothened to make a haze range to a specific range satisfies both the light transmitting property and the electromagnetic shielding ability, shows less surface light scattering, and can be produced at low cost. The effect is further increased by conducting metal addition by plating on the conductive metal part, and adjusting thickness of the optically transparent part. By using the optically transparent electromagnetic shielding film having a conductive metal mesh comprising a developed silver having a small haze value, it is not necessary to particularly provide an improvement step of light scattering, and production of an optical filer laminate can be simplified. Because position matching is not necessary, production rate is improved, and waste of materials is avoided.

The optically transparent electromagnetic shielding film can be used as an optical filter having the above characteristics by laminating with other functional layer. Additionally, the electromagnetic shielding film of the invention can be mass-produced inexpensively.

The entire disclosure of each and every foreign patent application from which the benefit of foreign priority has been claimed in the present application is incorporated herein by reference, as if fully set forth.

Claims

1. An optically transparent electromagnetic shielding film, which comprises: a transparent support; a conductive metal part; and a visible light transmitting part, wherein the conductive metal part is in the shape of a mesh made of fine wires having a wire width of from 1 to 40 μm, the conductive metal part has a thickness of from 1 to 6 μm, and a haze value of the optically transparent electromagnetic shielding film is from 0.1 to 10%.

2. The optically transparent electromagnetic shielding film according to claim 1, wherein the conductive metal part and the visible light transmitting part are formed by subjecting pattern exposure and development treatment to a silver salt photosensitive material which comprises an emulsion layer containing a silver halide.

3. The optically transparent electromagnetic shielding film according to claim 2, wherein the silver salt photosensitive material comprises at least one hydrophilic colloid layer, and the silver salt photosensitive material is roll-shaped.

4. The optically transparent electromagnetic shielding film according to claim 3, wherein the hydrophilic colloid layer has a thickness of from 0.5 to 2 μm.

5. The optically transparent electromagnetic shielding film according to any of claims 1 to 4, wherein 20% or more of a surface area of the conductive metal part is black.

6. The optically transparent electromagnetic shielding film according to any of claims 2 to 5, wherein the conductive metal part comprises a developed silver formed by the development treatment and a metal deposit added on the developed silver by electroless plating treatment or electrolytic plating treatment.

7. The optically transparent electromagnetic shielding film according to any of claims 2 to 6, wherein, while the silver salt photosensitive material is transported, the pattern exposure is conducted through a photomask and the development treatment is conducted.

8. An optical filter comprising an optically transparent electromagnetic shielding film according to any of claims 1 to 7.

9. The optical filter according to claim 8, which further comprises a functional transparent layer having at least one function selected from the group consisting of infrared shielding property, hard coating property, antireflective property, glare-proof property, antistatic property, ultraviolet shielding property, gas barrier property and display panel breakage prevention property.

10. The optical filter according to claim 8 or 9, which further comprises an adhesive layer.

11. The optical filter according to any of claims 8 to 10, which further comprises a peelable protective film.

12. The optical filter according to any of claims 8 to 11, wherein the conductive metal part and the visible light transmitting part of the optically transparent electromagnetic shielding film are arranged outermost.

13. The optical filter according to any of claims 9 to 12, which comprises the optically transparent electromagnetic shielding film, an infrared absorption filter having the infrared shielding property, an antireflective film having the antireflective property and a transparent substrate, wherein the optically transparent electromagnetic shielding film is arranged at one side of the transparent substrate and the infrared absorption filter and the antireflective film are arranged at the other side of the transparent substrate.