JP2012089782A - Electroconductive external light-shielding material, electroconductive external light-shielding sheet body, front filter for image display device, and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: an electroconductive external light-shielding material having electromagnetic-wave shielding properties and external light-shielding properties; an electroconductive external light-shielding material sheet body; a front filter for an image display device using these; and the image display device having the front filter.SOLUTION: An electroconductive external light-shielding material 100 has light-shielding filament patterns 10. The light-shielding filament patterns 10 are continuously arranged in an extending direction, and have trapezoidal shaped or approximately trapezoidal shaped light-shielding filaments 21 which have wide lower bottoms as cross sections perpendicular to the extending direction, and light-transmissive regions 22 formed of a transparent resin layer 20 and continuously arranged between the light-shielding filaments at predetermined gaps, arranged therein. The light-shielding filament 21 is formed of metal particles 1 and a binder resin 2. At least one part of the metal particles 1 is exposed to the outside from the wide lower bottom side, and the exposed part of the metal particles 1 has a groove-shaped recessed part and microprotrusions on the surface thereof.

Description

  The present invention improves the contrast used for a front filter for an image display device and the like disposed on the viewer side of an image display unit of an image display device such as a plasma display panel (hereinafter sometimes simply referred to as PDP). The present invention relates to a conductive external light shielding material having a function and an electromagnetic wave shielding function, a conductive external light shielding sheet, a filter for a front surface of an image display device having a contrast enhancement function using the same, and an image display device using the same.

An image display device such as a PDP is known to include a so-called micro louver layer as a constituent layer in a front filter in order to prevent a decrease in screen contrast due to reflection of extraneous light on the screen.
In Patent Document 1, a transparent resin layer is laminated on the surface of a filter base, and a wedge-shaped black stripe-shaped light shielding pattern including a light shielding conductive material in the transparent resin layer is arranged in parallel with each other at a predetermined interval. A display filter arranged in the above has been proposed. The light-shielding pattern has a wedge-shaped black stripe shape in which a light-shielding conductive material is selected from particles such as metal, carbon (carbon), and a conductive polymer material. And it is disclosed that this light-shielding wedge-shaped pattern is used as an electromagnetic wave shielding material such as PDP and an external light shielding sheet.

JP 2007-243185 A

However, in the display filter described in Patent Document 1, when the conductive particles of the light-shielding pattern are a metal such as silver, the reflectance from the particle surface is high, the external light absorption is insufficient, and the image contrast improving effect is obtained. It is insufficient.
On the other hand, when carbon-derived particles such as graphite are used as the conductive particles in order to suppress the external light reflectance, the conductivity of the particles is insufficient and the electromagnetic wave shielding properties are insufficient.
This is because light reflection performance and electromagnetic wave reflection performance are generally attributed to responsiveness of free electrons inside the material to the electromagnetic field as physical properties of the material, particularly metal. That is, in the blackened layer, the lower the light reflectance, the lower the electromagnetic wave reflectivity, that is, the electromagnetic wave shielding property. Therefore, conventionally, it has been difficult for the blackened layer to achieve both external light absorption performance and electromagnetic wave shielding performance.
Thus, in the conventional conductive particles, it is difficult to achieve both electromagnetic wave shielding properties and external light shielding properties, and there is a conductive external light shielding material using conductive light-absorbing particles having electromagnetic wave shielding properties and external light shielding properties. It was sought after.
The present invention has been made to solve the above-described problems, and is a conductive external light shielding material having an electromagnetic wave shielding property and an external light shielding property, a conductive external light shielding material sheet, and an image using them. It is an object to provide a front filter for a display device and an image display device including the front filter.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have a structure in which the dark-colored metal particles of the light-shielding filaments have a groove-shaped recess and a minute protrusion on at least the surface of the exposed portion. I found that it could be solved. The present invention has been completed based on such findings.
That is, the present invention
(1) A conductive external light shielding material having a light shielding line pattern, wherein the light shielding line pattern is continuous in the extending direction, and a cross section perpendicular to the extending direction has a wide lower bottom. A trapezoidal or substantially trapezoidal light-shielding filament, and a light-transmitting region composed of a transparent resin layer continuous with a predetermined gap between the light-shielding filaments, the light-shielding filament comprising dark metal particles It is made of a binder resin, and at least a part of the dark metal particles is exposed from the lower bottom side of the wide, and the exposed part of the dark metal particles has a groove-like recess and a minute protrusion on the surface thereof. Conductive external light shielding material,
(2) A conductive external light shielding material sheet formed by laminating the conductive external light shielding material according to (1) and a transparent support,
(3) A front filter for an image display device in which a functional layer is laminated on the surface and / or the back surface of the conductive external light shielding material according to (1), and (4) the conductivity according to (1). An image display device comprising a front filter including an external light shielding material or the conductive external light shielding material sheet according to (2),
Is to provide.

The conductive external light shielding material of the present invention is a light-shielding filament pattern containing dark metal particles and a binder resin, wherein at least a part of the dark metal particles of the light-shielding filament is exposed from the lower bottom side of the wide, Since the exposed portion of the dark metal particles has groove-shaped recesses and minute protrusions on the surface thereof, at least the light-shielding linear pattern layer surface has a dark color. That is, external light reflection is suppressed by the fine structure of the metal particle surface. For this reason, it exhibits excellent anti-reflection performance against external light, and the surface of the light-shielding linear pattern layer is not covered with a high-electrical resistance blackening layer. Performance and external light absorption performance are compatible.
Further, since no further metal plating process is required for the blackening treatment of the light-shielding filaments, an increase in cost associated with the plating process and an increase in the number of heavy metal recovery processes in the waste liquid can be suppressed to a minimum.
The conductive external light shielding material of the present invention can be used as a constituent filter of a front filter for an image display device having an electromagnetic wave shielding property and an external light shielding property by grounding an end portion thereof.

It is a perspective schematic diagram of the light-shielding filament pattern in the electroconductive external light shielding material of this invention. It is the (A) expansion perspective schematic diagram of the light-shielding filament pattern in the electroconductive external light shielding material of this invention, (B) An expanded sectional view. It is a SEM photograph of the dark color metal particle surface of the exposed part of the light-shielding filament pattern in the electroconductive external light shielding material of this invention. (A) A cross-sectional schematic diagram for demonstrating the structure of the light-shielding filament pattern in the electroconductive external light shielding material of this invention. (B) It is a plane schematic diagram. It is a partial expanded schematic cross section of the electroconductive external light shielding material sheet | seat body of the 2nd embodiment of this invention. It is a schematic cross section of the electroconductive external light shielding material sheet | seat body of the 1st embodiment of this invention. It is a conceptual schematic diagram of a front filter for an image display device by laminating one or more functional layers on the front surface and / or back surface of the conductive external light shielding material of the present invention. It is a schematic cross section which shows the structure of the image display apparatus which uses the electroconductive external light shielding material or electroconductive external light shielding material sheet | seat body of this invention as a front filter.

[Conductive light shielding material]
As shown in FIG. 1, the conductive external light shielding material 100 according to the present invention has a cross section (hereinafter referred to as “main cut surface”) in which the light shielding linear pattern 10 is continuous in the extending direction and is perpendicular to the extending direction. Is a trapezoidal or substantially trapezoidal light-shielding filament 21 having a wide bottom, and a transparent region (hereinafter referred to as a transparent resin layer 20) connected to the light-shielding filament 21 with a predetermined gap. 22), the light-shielding filament 21 is composed of the dark metal particles 1 ′ and the binder resin 2, and at least a part of the dark metal particles 1 ′ is a part of the dark metal particles 1 ′. As shown in FIG. 2 (B), the exposed portion of the dark metal particle 1 ′ is exposed on the surface as shown in FIG. 2 (B). And a minute protrusion 1p.

The light-shielding linear pattern 10 is formed by filling the groove portions 3 provided between the light-transmitting regions 22 made of the transparent resin layer 20 with the dark metal particles 1 ′ and the binder resin 2. ing.
The conductive external light shielding material of the present invention is also called a contrast enhancing layer, a microlouver layer, or a microlouver layer from the viewpoint of optical functions. Hereinafter, the 1st embodiment of the electroconductive external light shielding material of this invention is demonstrated.

[First embodiment of conductive external light shielding material]
FIG. 4 is a schematic cross-sectional view (A) showing an example of the first embodiment of the conductive external light shielding material 100 of the present invention, and a plan view (B) viewed from the dark color part side, FIG. 6 is a cross-sectional view of the conductive external light shielding material sheet 101 of the present invention provided with the transparent support 30.

  As shown in FIG. 1, the conductive external light shielding material 100 of the present invention is provided on one surface of a transparent resin layer 20 (hereinafter also referred to as “transparent substrate”). A linear light shield arranged in parallel along one direction (the direction from the near side to the far side in FIG. 1), and the main cut surface shape perpendicular to the extending direction is trapezoidal or substantially trapezoidal. And a light-transmitting region 22 composed of a transparent resin layer 20 between adjacent light-shielding filaments 21 and 21. The light-shielding filament 21 is filled with dark metal particles 1 ′ and a transparent binder resin (hereinafter simply referred to as “transparent resin”) 2 in a groove 3 having a trapezoidal or substantially trapezoidal main cut surface shape. Has been configured.

  In the conductive external light shielding material 100 of the present invention having such a configuration, the light-transmitting region 22 does not include the dark metal particles 1 ′, and the light transmittance of the light passing through the light-transmitting region is not deteriorated. The display image is not darkened and the visibility of the display image is not impaired. Further, in the light-shielding filament 21, at least the exposed dark metal particle 1 ′ has the minute protrusions 1p and the groove-shaped recess 1v as shown in FIG. If this is used as the front filter of the image display device, the contrast of the image (defined by the luminance ratio or difference between the white portion and the black portion of the image) can be improved.

  Hereafter, each component of the electroconductive external light shielding material in the 1st embodiment of this invention is demonstrated in detail.

[Transparent resin layer]
As the transparent resin layer 20, various kinds of resin materials such as ionizing radiation curable resins, thermosetting resins and thermoplastic resins, or inorganic transparent materials such as glass can be used. Usually, a resin material is preferably used in that the grooves 3 can be easily formed, can be light and thin, and are excellent in flexibility. About ionizing radiation curable resin and thermosetting resin, it can select from the thing similar to what was illustrated by the description location of the binder resin mentioned later, and can be used. Examples of the thermoplastic resin include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), ethylene glycol-terephthalic acid-isophthalic acid copolymer, terephthalic acid-ethylene glycol-1,4 cyclohexanedimethanol copolymer, polyester. Polyester resins such as thermoplastic elastomers, polyolefin resins such as polyethylene, polypropylene, cyclic polyolefin and polymethylpentene, halogen-containing resins such as polyvinyl chloride and polyvinylidene chloride, and styrene resins such as polystyrene and acrylonitrile-styrene copolymers , Cellulose resins such as triacetyl cellulose, diacetyl cellulose, acetate butyrate cellulose, thermoplastic polyurethane resins, polycarbonate resins, polyamide resins, There can be used.

  Since the groove part 3 is formed in this transparent base material 20, the thickness needs to be the same as the depth H of the groove part 3, or thicker than that, and it is the range of about 20 micrometers-5000 micrometers normally. That is, the transparent substrate 20 can take various forms of a so-called film, sheet, or plate in terms of thickness.

[Light-shielding filament (light-shielding filament pattern)]
As shown in FIGS. 1 and 4, the light-shielding linear pattern 10 is formed on one surface S <b> 1 of the transparent substrate 20, and is in one direction within the surface of the transparent substrate 20 (FIG. 4A). In this case, the shape is linear and the main cutting surface is formed in a trapezoidal shape or a substantially trapezoidal shape parallel to each other along the direction from the front surface side to the back surface side of the paper surface. And this light-shielding filament 21 is comprised by filling the metal particle 1 and the transparent binder resin 2 in the groove part 3 whose main cut surface shape is trapezoid or substantially trapezoid.

  First, the shape of the groove 3 will be described. As shown in FIGS. 1 and 4A, the groove 3 has a trapezoidal or substantially trapezoidal main cut surface. In addition, as shown in FIG. 4A, the trapezoidal groove-like recess has a wide width W on one side S1 side (lower bottom) of the transparent substrate 20 and a side on the other side S2 ( The width of the upper bottom) is configured in a narrow manner. In addition, the substantially trapezoidal groove-like recess includes a shape having a small difference in width between both sides (upper base and lower base), that is, a shape close to a rectangle or a square. A shape approximating a triangle cut by a plane parallel to the side (bottom base) is also included. The shape of the main cut surface of the groove 3 is not limited to such a trapezoid or a substantially trapezoid, but a perfect square, a rectangle such as a rectangle, a polygon such as a triangle, a pentagon, a hexagon, an octagon, a circle, an ellipse, a parabola, Although it may be a curve such as a hyperbola, it is preferably the trapezoid or substantially trapezoid described above.

In particular, in terms of the effect of improving the image contrast in the presence of external light, the groove 3 has a trapezoidal main cut surface shape, and there is a significant difference in the width of opposite sides (upper and lower bases). The viewer has a wide bottom on the side (ie, the surface S1 side), a narrow bottom on the image display device side (ie, the side of the surface S2), and the width of the side (lower base) with the larger groove depth H ( It is preferable that it is larger than (maximum width) W.
Further, in terms of image brightness (brightness) and high viewing angle of the image, the main cut surface shape of the groove 3 is trapezoidal, the image display device is provided with a lower base, and the groove depth H is the lowest at the lower base. It is preferable that it is significantly smaller than W.

  Thus, since the groove part 3 can set the maximum width W and the depth H independently, the maximum width W can be reduced, and if necessary, the repetition period between the groove-like recesses can be further increased. In addition to increasing the rate, the depth H is increased, and the surface area of the side portion (side surface extending in the depth H direction) of the light-shielding filament 10 that absorbs most of the external light incident from the oblique direction is increased. This makes it possible to achieve both high light transmittance of image light and high light absorption rate of external light. Here, the aperture ratio refers to the opening (the portion where the light shielding line 21 is not formed, that is, the translucent region 22) with respect to the entire area viewed from the normal direction of the conductive external light shielding material 100. The area ratio.

  The angle θ between the inclined surface 5 formed by the interface between the groove 3 and the transparent substrate 20 and the normal line of the light exit surface (line v parallel to the perpendicular incident light with respect to the conductive external light shielding material) is formed at a predetermined angle. For example, θ is preferably in the range of 3 ° to 15 °. When θ is within this range, even when the lower base of the groove 3 is placed on either the viewer side or the image display device side, the image brightness is improved and the reflection of external light is suppressed. The effect of improving the contrast and the high viewing angle effect of the image can be balanced appropriately.

  In addition, it is preferable that the length (namely, maximum width W) of the larger base (lower base) of the groove part 3 is about 10 micrometers-100 micrometers, and the length of the smaller base (upper base) is about 5 micrometers-50 micrometers. The depth H is preferably about 10 μm to 200 μm, the period (pitch) of the groove 3 is preferably about 10 μm to 900 μm, and the aperture ratio is about 50% to 90%. preferable.

As the metal particles 1 constituting the light-shielding filament 21, low resistivity metal particles such as gold, silver, platinum, copper, nickel, tin, and aluminum are used in order to ensure sufficient conductivity.
The shape of the metal particles can be selected from various polyhedron shapes such as regular polyhedron shape, truncated polyhedron shape, spherical shape, spheroid shape, scale shape, disc shape, dendritic shape, fibrous shape, etc. The metal particles to be used are required to have at least an exposed portion from the lower bottom portion having a plurality of groove-shaped concave portions on the surface in the state of at least dark metal particles 1 ′.
The size of the metal particles is arbitrarily selected according to the type of metal and the size of the light-shielding filament, so it cannot be specified unconditionally, but preferably the one having an average particle size of about 0.01 to 10 μm is used. Can do. However, the maximum particle diameter is selected so as to be smaller than the minimum values of the depth H and the width of the groove 3 constituting the light shielding line. In order to obtain good electrical conductivity by lowering the electrical resistance of the obtained conductive external light shielding material (preferably having a surface resistivity of 0.8Ω / □ or less), it is preferable that the average particle diameter is small. From the viewpoint, an average particle size of 0.1 to 1 μm is preferable. In addition, regarding the particle size distribution, in order to reduce the electric resistance of the conductive pattern obtained, the particle size distribution is relatively small compared to particles having a relatively large particle size rather than a narrow distribution width and close to a single particle size. It is better to consist of a mixed system with particles of a particle size.
The content of the metal particles in the light-shielding filament is arbitrarily selected according to the conductivity of the metal particles and the form of the particles, but it is suitable for the expression of suitable conductivity and the mechanical strength of the conductive external light shielding material. From the standpoints of maintenance and filling into the concave groove, etc., for example, among 100 parts by mass of the solid content of the light-shielding filament composition, the metal particles are in the range of 40 to 99 parts by mass, more preferably 90 to 97 parts by mass. It can be included. In the present specification, the average particle diameter refers to a value measured by a particle size distribution meter or TEM (transmission electron microscope) observation.
When measuring the particle diameter by observation, when the particle shape is a sphere, the diameter is the particle diameter. When the particle shape is non-spherical, the diameter of the circumscribed sphere of the particle is used as the particle diameter.

  The light-shielding filament 21 is darkened by post-processing so that at least a part of the metal particle 1 is exposed from the lower bottom side of the wide portion, the metal particle has a groove-shaped recess and a minute protrusion on the surface. As a result, dark metal particles 1 ′ are formed, and a dark color such as black is exhibited. Before darkening, the metal particle 1 ′ does not necessarily have a dark color. The darkening of the metal particles will be described later. In the specification of the present application, at least the exposed portion E is darkened by the groove-shaped recess 1v and the minute protrusion 1p as “dark-colored metal particle 1 ′”, or the state in which such darkening is not performed. The metal particles in a state where the darkening treatment has not been performed are simply referred to as “metal particles 1”.

  Various materials such as ionizing radiation curable resins, thermosetting resins, and thermoplastic resins can be used as the transparent binder resin 2 that constitutes the dark portion (light-shielding filament) together with the metal particles 1. The ionizing radiation curable resin means a resin that is cured by crosslinking or polymerization reaction by irradiation with electromagnetic waves or charged particle beams such as ultraviolet rays or electron beams. Examples of such an ionizing radiation curable resin include an ionizing radiation polymerizable prepolymer and / or an ionizing radiation polymerizable monomer.

  Examples of the ionizing radiation polymerizable prepolymer (used to include oligomers) include polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, polyol (meth) acrylate, silicon (meta) ) In a molecule such as an epoxy resin such as a polymerizable oligomer having a radical polymerizable functional group in a molecule such as acrylate or unsaturated polyester, or a novolak type epoxy resin prepolymer or an aromatic vinyl ether resin prepolymer. Examples thereof include a polymerizable oligomer having a cationic polymerizable functional group. These ionizing radiation polymerizable prepolymers may be used singly or in combination of two or more. Here, “(meth) acrylate” means “acrylate or methacrylate”.

  The ionizing radiation polymerizable monomer (monomer) is preferably a polyfunctional (meth) acrylate which is a polymerizable monomer having a radical polymerizable functional group in the molecule, specifically ethylene glycol di (meth). Acrylate, propylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate, etc. It is done. Examples of the monomer having a cationic polymerizable functional group include alicyclic epoxides such as 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, and glycidyl ethers such as bisphenol A diglycidyl ether. , Vinyl ethers such as 4-hydroxybutyl vinyl ether, and oxetanes such as 3-ethyl-3-hydroxymethyloxetane. These ionizing radiation polymerizable monomers may be used alone or in combination of two or more, or may be used in combination with the ionizing radiation polymerizable prepolymer.

  When an ultraviolet curable resin is used as the ionizing radiation curable resin, it is desirable to add about 0.1 to 5 parts by mass of the photopolymerization initiator with respect to 100 parts by mass of the ionizing radiation curable resin. The initiator for photopolymerization can be appropriately selected from those conventionally used and is not particularly limited.

  For polymerizable monomers and polymerizable oligomers having a radical polymerizable functional group in the molecule, benzoin, benzoin methyl ether, acetophenone, dimethylaminoacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1- ON, 1-hydroxycyclohexyl phenyl ketone, benzophenone, p-phenylbenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal and the like. For polymerizable monomers and polymerizable oligomers having a cationic polymerizable functional group in the molecule, aromatic sulfonium salts, aromatic diazonium salts, aromatic iodonium salts, metallocene compounds, benzoin sulfonic acid esters, etc. Can be mentioned. Moreover, as a photosensitizer, p-dimethylbenzoic acid ester, tertiary amines, a thiol type sensitizer, etc. can be used, for example.

  Thermosetting resins include phenolic resin, phenol-formalin resin, urea resin, urea-formalin resin, melamine resin, polyester-melamine resin, melamine-formalin resin, alkyd resin, epoxy resin, epoxy-melamine resin, unsaturated polyester. Examples thereof include resins, polyimide resins, acrylic resins, polysiloxane resins, polyurethane resins, general-purpose two-component curable acrylic resins (acrylic polyol cured products), and the like.

(Translucent area)
The translucent area | region 22 is comprised from the part located between the adjacent light-shielding filament 21 and 21, among the transparent resin which comprises the transparent base material 20, as shown in FIG.1 and FIG.4.

  In the conductive external light shielding material of the present invention, the transparent binder resin 2 for binding the metal particles used for the light shielding line and the resin constituting the transparent resin layer (transparent substrate) 20 are both ionized. A radiation cross-linked resin is preferable because, together with the improvement in productivity of the conductive external light shielding material, a concave portion 23 having an appropriate depth accompanying curing shrinkage can be obtained.

[Exposed portion of metal particles in light-shielding filament]
As shown in FIG. 4, the conductive external light shielding material of the present invention has a recessed portion 23 on the lower bottom side of the trapezoidal light shielding line. The concave portion 23 is formed by curing shrinkage and drying shrinkage that occur when the metal particles 1 and the binder resin 2 are filled in the groove portion 3 of the transparent base material 20 and are cured or dried. With the formation of the recessed portion 23, the surface of the metal particle 1 existing in the vicinity of the lower bottom surface is exposed. The depth of the recessed portion 23 depends to some extent also on the properties of the resin such as the solvent concentration of the dark ink prepared by adding a solvent or the like to the metal particles 1 and the binder resin 2, the crosslinking density of the binder resin, and the processing conditions. The dependency on the properties of these resins is that the recesses 23 are formed mainly by volume contraction when the resin is filled in the grooves 3 and solidified (cured). The dependence on the processing conditions mainly depends on the hydrodynamic or rheological behavior of the resin when the resin is filled in the grooves 3 in liquid form. In particular, as will be described later, a dark resin composition of light-shielding filaments composed of metal particles 1 and transparent resin 2 is applied and supplied onto the groove 3, and after that, the surplus composition other than the groove is applied to the doctor. In the case of performing the so-called wiping method of scraping with a blade or the like, it depends on the scraping speed, pressing pressure, inclination angle, elastic constant or rubber hardness of the doctor blade or the like. By controlling the dependency on the properties of these resins and the dependency on processing conditions, a desired depth can be obtained.
The depth of the recessed portion 23 is naturally determined by the dark resin composition and the processing method. When the dark resin composition made of the material as described above is filled into the groove 3 by a so-called wiping method, the depth H of the groove 3 is in the range of 10 μm to 200 μm.
The maximum depth refers to the depth of the maximum depth portion from the reference plane, and is measured from the cross section of the conductive external light shielding material magnified 500 to 1000 times with a magnifying glass.
Further, in FIG. 2A, the concave portion 23 is expressed in a curved shape, but this is an example, and the surface is not necessarily smooth depending on the particle size or concentration of the metal particles in the composition of the dark ink. Various types of recesses may appear, such as none.

The conductive external light shielding material in the present invention is a surface layer of the light shielding line pattern 10, and the dark metal particles 1 ′ partially exposed from the bottom surface of the light shielding line have a specific microstructure on the surface. Due to the dark color. That is, as shown in FIGS. 2A and 2B, a part of the dark metal particle 1 ′ is exposed from the binder resin 2, and at least the exposed part E of the dark metal particle 1 ′ has a groove-like recess 1v on its surface. And the minute protrusions 1p, and the morphological characteristics give a dark color.
The exposure ratio of the metal particles 1 (dark metal particles 1 ′) in the exposed portion E of the dark metal particles is sufficient to darken the surface of the dark metal particles and prevent the dark metal particles from falling off the light-shielding linear pattern 10. Therefore, the total volume of the metal particles is 10 to 60%, preferably 20 to 50%.
Further, the shape of the groove-like recess 1v of the dark metal particles preferably runs in the shape of a trough on the surface of the dark metal particle exposed portion, and the trough is meandered, branched, or meandered and branched. It takes the form. Due to the surface structure of the exposed portion of the metal particles, the reflected light is scattered or attenuated, the specular reflectivity of the surface of the light-shielding linear pattern 10 is lowered, and the surface is dark.
The metal particle diameter d _m of the dark metal particles 1 'is 0.1 to 10 [mu] m, the microprojection diameter d _p is smaller than the dark color metal particle diameter, a 0.01 to 0.1 m, 1/1000 ≦ d _p / d _m ≦ 1/10. The particle diameters d _m and d _p are defined as the diameters of circumscribed spheres when the particles are non-spherical.
The minute protrusions 1p may be either adhesion of fine particles independent of the dark metal particles 1 ′ or protrusions of the dark metal particles themselves. Further, the minute protrusion 1p may be made of the same material or different material as the metal particle 1. Further, the shape of the minute protrusion 1p is, for example, a sphere, a spheroid, a polyhedron, or a needle shape, or a part thereof (hemisphere or the like).
The number of protrusions of the minute protrusion 1p is 10 to 1000 pieces / one exposed metal particle, and preferably 100 to 1000 pieces / one exposed metal particle.
The dark color which the surface of such a light-shielding linear pattern 10 exhibits is the structure of the groove-like recessed part 1v and the minute protrusion 1p of the exposed part of the metal particle 1 (planar shape of groove-like recessed part, groove width, groove depth). The cross-sectional shape of the groove, the number of grooves, the state of branching and meandering, and the size, shape, number density of the fine protrusions, etc.) Depending on the processing conditions of the darkening method, various brightnesses, saturations, and hues can be exhibited, but in order to reduce the reflectance of the metal particle surface, particularly the specular reflectance, low brightness achromatic or presence Colored, that is, dark. Specifically, the dark color is typically black, but (dark) gray, brown, amber, dark green, rosy, dark purple, and the like are also possible.

[Darkening method of shading line pattern]
The surface structure of the exposed portion of the metal particles on the surface of the light-shielding linear pattern can be produced as follows.
That is, the light-shielding linear pattern layer including the metal particles 1 and the binder resin 2 on one surface side of the transparent substrate 20, and a part of the metal particles 1 exposed from the binder resin 2 on the wide bottom surface. The conductive external light shielding material formed with C.I. is, for example, an aqueous hydrochloric acid solution in which tellurium is dissolved as described later, or C.I. commercially available from Bayer under the trade name NIGROSIN WLF (registered trademark). I. By immersing in a metal darkening treatment solution such as hydrochloric acid solution in which Acid Black 2 (C.I. No. 50420) is dissolved, and then washing with water and drying, the metal particles 1 are exposed to the above-mentioned surface E. A structure is formed, resulting in dark metal particles 1 ′. Thereby, the electroconductive external light shielding material 100 of this invention by which the light-shielding filament 21 was darkened can be obtained. In particular, the above processing method is suitable when the metal particles 1 are silver particles.
Note that the metal particles embedded in the binder resin without the exposed portion E may or may not have the groove-shaped recess 1v and the minute protrusion 1p.
The minute protrusions 1p are usually formed by performing a specific darkening process on the light-shielding filament 21 in which a part of the metal particles 1 is exposed from the binder resin. In this case, the minute protrusion 1p is formed only on the exposed portion E of the metal particle. On the other hand, if the darkening treatment is performed in the state of the metal particles 1 alone before being added to the binder resin 2, the fine protrusions 1p are formed on all the metal particles, that is, the portion embedded in the binder resin of the metal particles. (Not shown).
In addition, the groove-like recess 1v is usually formed in the middle process of manufacturing the metal particle 1. In this case, the groove-like concave portion 1v is also formed in all metal particles, that is, a portion embedded in the binder resin of the metal particles. On the other hand, it is also possible to form the groove-shaped recess 1v by a corrosion process, a plating process or the like on the light-shielding filament 21 in which a part of the metal particle 1 in which the groove-shaped recess 1v is not formed is exposed from the binder resin. In this case, the groove vertical and horizontal recesses 1v are formed only in the metal particle exposed portion E.

In these metal darkening methods, it is not yet clear what substance / material the minute protrusions 1p of the exposed part E of the metal particles are made of.
That the light-shielding striatum using the silver particles treated with tellurium aqueous hydrochloric acid method as the metal particles are fine small _{protrusions, TeCl 2, Te, TeCl 4} , AgCl, at least one of TeO _2, AgO, Ag ₂ O 1 element may be included, but when analysis was performed using an energy dispersive X-ray Fluorescence Spectrometer (EDX), Cl element and Ag element were confirmed. It was.
Therefore, from this analysis result and the color tone of the dark color layer, the dark color layer contains, in particular, AgCl, a reaction product produced by reaction of AgCl with light (considered as Ag (silver)), or Ag ₂ O. It is speculated that.
In addition, C.I. I. The following can be said with respect to Acid Black 2 aqueous hydrochloric acid treatment.
A coating film containing only a binder resin is used for C.I. I. Even when immersed in Acid Black 2 hydrochloric acid aqueous solution, the resin is not colored (dyed), and the light-shielding linear pattern layer using silver particles as the metal particles is made of hydrochloric acid alone or C.I. I. Even when immersed in an aqueous solution of only Acid Black 2, the light-shielding linear pattern layer is not colored (dyed). I. Coloring and darkening of the surface of the light-shielding filamentous pattern layer are observed only after immersion in Acid Black 2 hydrochloric acid aqueous solution. In this case as well, C.I. I. Acid Black 2 is not detected, and it is unclear what substance / material the microprotrusion 1p is made of, but from analysis results such as elemental analysis, it is presumed that AgCl or Ag has been reduced by light or the like.

The following are mentioned as a metal darkening process liquid used at this process.
The first metal darkening solution is an aqueous hydrochloric acid solution in which tellurium is dissolved.
It is preferable to use tellurium oxide as the source of tellurium.
In this metal darkening treatment solution, tellurium is contained in an amount in the range of 0.01 to 0.45% by weight, preferably 0.05 to 0.40% by weight, in terms of oxide. Yes. Since this metal darkening treatment liquid has a tellurium concentration lower than the treatment solution used in the blackening treatment of the surface of metal products conventionally performed using this kind of treatment solution, a thin dark layer can be formed. it can. In addition, tellurium is present in the treatment solution in a state dissolved in hydrochloric acid, and is very stable. Even when the metal darkening treatment solution is left for a long time, the compound is difficult to precipitate, so that it is a one-component type. It can be a treating agent. Furthermore, since the stability of the one-pack type metal darkening treatment solution does not deteriorate even after contact with the treatment metal, it can be used repeatedly.

An aqueous hydrochloric acid solution that dissolves tellurium oxide is usually formed by blending water with 35% hydrochloric acid (hereinafter also simply referred to as hydrochloric acid). The concentration of HCl (hydrogen chloride) in the aqueous hydrochloric acid solution is in the range of 0.05 to 8% by weight, preferably 0.1 to 2% by weight, and more preferably 0.3 to 1% by weight. By using an aqueous hydrochloric acid solution having such a concentration, the tellurium oxide can be completely dissolved.
Moreover, according to the darkening treatment liquid having the HCl concentration, the darkening treatment product obtained is excellent in antireflection performance.
When the HCl concentration exceeds 8% by weight, the antireflection performance may be inferior. When the HCl concentration is less than 0.05% by weight, tellurium oxide may not be completely dissolved in the hydrochloric acid aqueous solution. .

In addition to the hydrochloric acid aqueous solution as described above, any organic acid and inorganic acid may be added. In order to increase the black density, it is preferable to contain sulfuric acid. The sulfuric acid concentration to be added is preferably 90% by weight or less from the viewpoint that a dark color with a high black concentration can be formed.
The sulfuric acid concentration in the darkening treatment liquid is further 10 to 45% by weight, particularly 15 to 30% by weight, and the treatment time can be shortened, and the darkness of the darkening layer obtained is excellent. To preferred.

The contact method between the metal darkening treatment liquid and the conductive external light shielding material having a light-shielding linear pattern on one side of the transparent substrate is not particularly limited. For example, dipping (immersion), curtain coating, pouring Or the like to bring it into contact with the light-shielding filament pattern.
The contact temperature between the metal darkening treatment liquid and the light-shielding linear pattern may be room temperature, and is preferably in the range of 10 to 40 ° C.
Under the temperature conditions as described above, the contact time between the light-shielding filament pattern and the metal darkening treatment liquid is usually 15 minutes or less, preferably 1 second to 2 minutes, particularly preferably 5 seconds to 30 seconds. As described above, according to the darkening process, the surface of the light-shielding linear pattern can be darkened to black or a dark color close to black in a very short time.

The second metal darkening treatment liquid is C.I. I. This is a hydrochloric acid aqueous solution in which Acid Black 2 is dissolved.
C. an acid-resistant dye I. Hydrochloric acid is added to an aqueous solution of Acid Black 2 to obtain a metal darkening treatment solution, and a conductive external light shielding material having a light-shielding filament pattern is immersed on one side of the transparent substrate.
In this metal darkening treatment liquid, C.I. I. Acid Black 2 is contained in a solid content of 15% by weight. The concentration of HCl (hydrogen chloride) in the metal darkening solution is 1% by weight.
The contact temperature between the metal darkening treatment liquid and the light shielding line pattern (liquid temperature of the metal darkening treatment liquid) may be room temperature, but the darkening degree increases by raising the temperature to about 60 ° C. The contact time (immersion time) is between 30 and 300 seconds, and there is no change in the darkening degree.

  In any metal darkening treatment, the transparent conductive material of the present invention can be obtained by washing with water and drying after the darkening treatment.

[Specific example of production of conductive external light shielding material]
A liquid urethane acrylate-based prepolymer, a dipentaerythritol hexaacrylate monomer, and a benzophenone-based polymer on one surface of a transparent substrate as a transparent support composed of a transparent biaxially stretched PET film having a thickness of 188 μm and a continuous belt shape A liquid ultraviolet curable resin composed of a mixture of photoinitiators was applied so that the film thickness after curing was 155 μm. Next, the main cutting surface has a height of 150 μm, the length of the base on the plate surface side is 30 μm, and the length of the base on the side far from the plate is continuous along the surface direction of the roll mold surface in the circumferential direction. Between a roll mold and a PET film formed with a convex stripe group (same shape and reverse irregularity as a light-shielding filament) in which a convex portion having a trapezoidal length of 6 μm is arranged in parallel with each other at a period of 60 μm By irradiating ultraviolet rays from a mercury lamp while sandwiching the applied ultraviolet curable resin, the ultraviolet curable resin is crosslinked and cured to form a transparent resin layer, and then the roll mold is released to release the transparent resin. The layer surface is connected in a straight line in one direction along the surface direction of the transparent resin layer surface, the main cut surface is 150 μm in height, the length of the bottom of the transparent resin layer surface side is 30 μm, and the bottom of the PET film side Grooves that form a trapezoid with a length of 6 μm A transparent resin layer having a surface Ranaru groove (lens portion) was formed on one surface of the transparent substrate. In 100 parts by mass of a transparent acrylic UV-curable prepolymer, metal particles (50 parts by mass of polyhedral silver particles having an average particle diameter of 1 μm, 1-hydroxy-cyclohexyl-phenyl-ketone as a photopolymerization initiator (product) Name: Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) was mixed to prepare a liquid UV-curable resin composition, which was applied to the groove of the transparent resin layer, and then the coating film was applied. Squeegee with an iron doctor blade to scrape and remove only the liquid composition outside the groove, and fill the liquid composition only inside the groove to form an uncolored conductive external light shielding material. did.
The polyhedral silver particles are polyhedral silver particles having an average particle diameter of 1 μm composed of particles having a particle diameter in the range of 0.1 to 3 μm. have. The particle diameter was determined as the diameter of the circumscribed sphere of each particle observed with a microscope.
At this stage, the surface resistance, which is an index for evaluating the conductive performance of the surface of the light-shielding linear pattern (the lower bottom side of the light-shielding linear pattern), was 0.9Ω / □.

[Darking treatment of conductive external light shielding material surface]
Next, as the metal darkening treatment solution, an aqueous solution of 0.17% by weight of tellurium dioxide (0.078% by weight as tellurium concentration), 0.45% by weight of hydrochloric acid, and 34.3% by weight of sulfuric acid was used. The uncolored conductive external light shielding material was immersed in the treatment liquid at a treatment temperature of 25 ° C. for 30 seconds, washed with water and dried to obtain the conductive external light shielding material of Embodiment 1.
The appearance of the light shielding line pattern of the conductive external light shielding material was changed from silver to black, and the reflectance from the surface side of the conductive external light shielding material was reduced by 5% compared with that before the treatment. The reflectance was measured using a haze meter HM150 (trade name, manufactured by Murakami Color Co., Ltd.) in accordance with JIS-K7105.
The surface resistance was 0.9Ω / □.
Further, when the surface of the light shielding line pattern of the conductive external light shielding material was observed by SEM, the exposed portion of the metal particles had a plurality of branched trough-shaped recesses 1v on the surface and a large number of average 10 nm. It was confirmed that the structure has a fine protrusion (fine particle) 1p (FIGS. 2B and 3). Further, the elements contained in the blackening layer were analyzed using an energy dispersive X-ray fluorescence analyzer (EDX: Energy Dispersive X-ray Fluorescence Spectrometer) (trade name: Genesis XM2, manufactured by EDAX). Cl element and Ag element were confirmed.

[Second embodiment of conductive external light shielding material]
As shown in FIG. 5, the conductive external light shielding material of the present invention is formed on the transparent support 40 as shown in FIG. 5 instead of the first embodiment formed by filling the grooves of the transparent substrate with metal particles and a binder resin. A light-shielding filament 21 is formed by printing on the first metal darkening treatment solution of hydrochloric acid solution in which tellurium is dissolved, or C.I. I. The second metal darkening treatment solution, which is a hydrochloric acid solution in which Acid Black2 is dissolved, darkens the metal particles exposed on the surface, and then the space between the darkened light-shielding filaments 21 is filled with a transparent resin. By using the translucent region 22, the conductive external light shielding material 102 of the second embodiment can be obtained.
Examples of the printing method include screen printing, gravure printing, and offset printing.
When the printing method is used, it is particularly possible to improve the gravure printing and apply the intaglio printing method disclosed by the present applicant as disclosed in the manufacturing method of the electromagnetic wave shielding material disclosed in the WO 2010/064630 pamphlet. It is preferable because a highly conductive light-shielding filament can be obtained, and from the high transfer rate from the intaglio, a groove with a relatively deep H of the light-shielding filament can be obtained.
Hereinafter, the outline in the case of applying this intaglio printing method to the conductive external light shielding material of the present invention will be described.

  In the intaglio printing method, after applying a conductive external light shielding material composition containing metal particles and a binder resin to a plate surface formed with a predetermined light-shielding filament, conductive external light attached outside the concave portion. The shielding material composition is scraped off, and the concave portion is filled with the conductive external light shielding material composition, and a transparent support having a liquid primer layer formed on one side thereof is pressure-bonded in such a direction that the primer layer is in contact with the intaglio plate. Then, the conductive external light shielding material composition in the concave portion and the primer layer are closely adhered without any gap, and in this state, the primer layer is solidified from a liquid state to a solid state, and then the transparent support is separated from the intaglio plate and released. By doing so, the conductive external light shielding material composition is transferred onto the solidified primer layer 50 on the transparent support 40 and printed.

After printing, that is, after release, the light-shielding filaments that are still in the liquid state are appropriately subjected to a drying operation, a heating operation, a cooling operation, a chemical reaction operation, and the like to solidify the conductive external light shielding material composition. The light-shielding filament is cured. The conductive external light shielding material composition may be semi-cured on the plate and completely cured after the release.
As described above, when the conductive external light shielding material composition is pulled out from the plate in an uncured or semi-cured state and is cured completely after release, the binder resin contracts and dark (metallic) metal particles A part is easily exposed from the binder resin, and is suitable for darkening the surface of the light-shielding filament.

In the production of the electromagnetic shielding material, in general, in intaglio printing, the conductive composition is supplied to the plate surface, and when the surplus composition is scraped off with a doctor blade or the like to fill the plate recess with the composition, A dent was generated on the surface of the filled composition, and due to the recess, there were problems such as poor adhesion to the transparent substrate and a decrease in the transfer rate of the composition onto the transparent substrate.
On the other hand, in the intaglio printing described in the pamphlet of WO2010 / 064630, even if a depression (dent) is formed in the upper part of the conductive composition filled in the intaglio depression, printing is performed through a liquid and fluid primer layer. The primer layer can be poured into the recess during printing so that the primer layer is in close contact with the gap, and then the primer layer is solidified, and then the transparent substrate is separated from the intaglio, so that the primer layer solidified on the transparent substrate A light-shielding filament having a predetermined pattern can be formed without occurrence of printing failure such as disconnection or shape failure due to insufficient transfer or insufficient ink adhesion.
Thus, as a result of the primer layer flowing in and filling the depressions formed on the surface of the ink filled in the intaglio depressions, the resulting conductive member has a thickness of the primer layer 50 as shown in FIG. The thickness of the portion where is formed becomes thicker than the thickness of the portion where the light-shielding filament is not formed. Such a feature can be similarly obtained in the present invention using a conductive external light shielding material composition instead of the conductive composition.

An uncolored conductive external light shielding material (precursor) can be prepared by such intaglio printing, and this is further treated as (i) hot water treatment in the presence of moisture and at a relatively high temperature. And / or (ii) by contacting with acid as the acid treatment, the volume resistivity and further the surface resistivity of the light-shielding filament can be lowered, and the conductive performance can be improved.
The hot water treatment of (i) is performed by immersing the conductive external light shielding material precursor in hot water having a water temperature of 30 to 100 ° C., flowing hot water over the conductive external light shielding material precursor, or air temperature 30 A method of exposing to an atmosphere of relative humidity of 60% or more at -100 ° C is preferable, and the treatment time is about 5 minutes to 20 seconds.
In the acid treatment of (ii), the acid is not particularly limited, and can be selected from various inorganic acids and organic acids, but is preferably hydrochloric acid, sulfuric acid, citric acid or an aqueous solution thereof, and the treatment time with the acid is several minutes. The following is sufficient, and the processing temperature is sufficient at room temperature. The method of treating with an acid is not particularly limited, but the method of immersing in an acid solution is preferable because of its excellent conductivity improving effect, and the acid concentration is preferably 1 mol / L or less, more preferably 0.1 mol / L. L or more. As the acid treatment, one type of acid may be used for contact once, or two or more types of acids may be used for sequential contact with another acid. In particular, when the electromagnetic wave shielding material is first immersed in hydrochloric acid and then immersed in citric acid, the electrical resistance reducing effect is better than when immersed in hydrochloric acid alone or in citric acid only once.

Among these electrical resistance reduction treatments, it is preferable to perform the hot water treatment (i) subsequently after the acid treatment (ii) from the viewpoint of the electrical resistance reduction effect and workability.
By such electrical resistance reduction treatment, the surface resistivity of the entire light-shielding linear layer of the conductive external light shielding material is reduced to about 80 to 30% before treatment (the apparent volume resistivity is similarly 80 before treatment). ˜30%).
The reason why the surface resistivity is reduced by the electrical resistance reduction process is that the metal particles 1 adjacent to each other with a spacing of 0 by the electrical resistance reduction process from the observation of the cross section of the light-shielding filament 10 by an electron micrograph. It is presumed that at least a part of each other forms a part having a continuous (fused) connection. Here, the fusion refers to a state in which the boundary surface (line) of the portion in contact with the adjacent metal particles at the interval 0 disappears and the adjacent particles are integrated in the contact portion in the electron microscope observation. On the other hand, in the state before performing the above-described electrical resistance reduction treatment, the boundary surface (line) is present in the portion in contact with the interval 0 of the adjacent metal particles in the electron microscope observation, and is simply in contact. Stays.

  In addition, after the above-described electrical resistance reduction treatment, the binder resin 2 exists in the gap between the metal particles 1 and the dark metal particles 1 ′ in the light-shielding filament 21, and the binder resin 2 bonds the gaps between the metal particles 1 and 1 and the dark metal particles 1 ′ and 1 ′ in a region excluding the region where the metal particles 1, 1 and 1 ′ and 1 ′ are fused. I'm coughing. In other words, the light-shielding filaments 21 before the darkening treatment have the metal particles 1 and 1 and the dark metal particles 1 ′ in the binder resin 2 as shown in the sectional view after the darkening treatment in FIG. , 1 'are dispersed, and adjacent metal particles 1, 1 and dark metal particles 1', 1 'between at least a part of these metal particles 1, 1 and metal particles 1', 1 '. The fused metal particles 1 and / or the dark metal particles 1 ′ are connected to each other to form a path through which an electric current can flow.

[Process for darkening the light-shielding filament surface]
In this step, a light-shielding filament 21 is formed on one surface side of the transparent support 40 produced in the above step, including the metal particles 1 and the binder resin 2, and a part of the metal particles 1 exposed from the binder resin on the surface. The surface structure is formed in the exposed portion E of the metal particle by immersing the precursor of the conductive external light shielding material in the metal darkening treatment liquid, and the metal particle 1 in the exposed portion E is turned into the dark metal particle. This is a step of darkening the surface of the light-shielding filament by converting it to 1 '.
The principle of darkening is the same as that described in the first embodiment.

  In the second embodiment, it is necessary to form the light-transmitting region 22 between the plurality of light-shielding filaments 21 darkened by the above method. As a method for forming the translucent region 22, a liquid transparent resin composition is applied to the entire surface of the light-shielding filament 21 formed on one surface of the transparent support 40 via the primer layer 50. A method of filling the space between the light-shielding filaments 21 and then curing the transparent resin composition to form the light-transmitting region 22 can be mentioned. As described above, the translucent region 22 includes a transparent binder resin for binding the dark metal particles 1 ′ used for the light-shielding filament 21 and a resin constituting the transparent resin layer (transparent substrate), Both ionizing radiation cross-linked resins are preferable because the productivity of the conductive external light shielding material is improved in combination with the ease of forming the translucent region.

[Third embodiment of conductive external light shielding material]
In the first embodiment, the exposed portion of the metal particles on the surface layer of the light-shielding filament is darkened, and in the second embodiment, the exposure of the metal particles of the light-shielding filament printed in a pattern is performed. The darkening process of the outer peripheral surface which is a part is possible. However, in the first embodiment, the metal particles filled in the grooves are in contact with the darkening treatment liquid or the like in the second embodiment, and the metal particles that are disposed inside the intaglio and are not exposed on the surface. Since there is no opportunity to do, it is not darkened.
Therefore, in the third embodiment of the present application, the metal particles themselves are darkened in advance, and the dark metal particles subjected to the darkening treatment are used as a light-shielding filament forming composition in the first embodiment. In the second embodiment, blended with the resin, similarly, by blending and printing the dark metal particles that have been darkened in advance to the light-shielding filament forming composition (ink) used for intaglio printing, A conductive external light shielding material can be manufactured. According to the third embodiment, since all the metal particles constituting the conductive external light shielding material are dark metal particles, it is not necessary to perform the metal darkening treatment liquid again in the post-treatment. Since all the metal particles constituting the light-shielding filament are dark-colored metal particles, a conductive external light shielding material having a high light-shielding effect can be provided.

[Conductive external light shielding material sheet]
Next, the conductive external light shielding material sheet of the present invention is formed by laminating the conductive external light shielding material and the transparent supports 30 to 40.
As shown in FIG. 6, the transparent support 30 is the surface S2 on the non-transparent protective layer forming side of the transparent base material 20 constituting the translucent region (see FIG. 6) in the conductive external light shielding material of the first embodiment. 4)) as required. The transparent support 30 supports the transparent substrate 20 and reinforces the mechanical strength of the transparent substrate 20, or forms a layer of the transparent substrate 20, forms the groove 3 on the transparent substrate 20, and dark color. It is preferably provided for the purpose of filling the groove portion 3 with the composition for forming a portion and imparting processability in processing steps such as laminating the conductive external light shielding material 100 on other members. The material of the transparent support 30 can be appropriately selected and applied from the materials described in the above-mentioned transparent base material 20 in view of the purpose of providing the transparent support 30, but is usually polyester resin, polyolefin resin, polychlorinated Vinyl or the like is used. Further, the thickness of the transparent support 30 may be appropriately selected in view of the purpose of providing the transparent support 30, but is usually about 20 to 200 μm.
Moreover, since the conductive external light shielding material by the intaglio printing method according to the second embodiment has the transparent base material 40 for forming the primer layer, it is not always necessary to newly provide the transparent support 30.

  In addition, the conductive external light shielding material of the present invention or the two sheets of conductive external light shielding material sheet of the present invention are laminated so that the light shielding filaments extending in the extending direction thereof are orthogonal to each other, and the respective edge portions Is grounded, the conductivity is improved and the electromagnetic shielding effect can be further enhanced.

[Front filter for image display device]
The conductive external light shielding material of the present application or the conductive external light shielding material sheet of the present invention is used for an image display device by laminating functional layers on the front surface (one surface) and / or the back surface (the other surface). It can be a front filter.
FIG. 7 is a conceptual schematic diagram of a front filter 300 for an image display device in which one or more functional layers 200 are laminated on the front surface and / or the back surface of the conductive external light shielding material 100 of the present invention. As the front filter, it is possible to form an optical filter that contains a functional material in the pressure-sensitive adhesive layer for laminating each functional layer and also serves as a functional layer, but apart from this, a filter having an independent function and , And can be used by being laminated through an adhesive layer. As this type of filter, for example, one or more types of optical materials selected from a near infrared absorption function, a neon light absorption function, a toning function, an ultraviolet absorption function, an antireflection function, an antiglare function, etc. A layer having a function, a film or sheet, or a plate material can be given. Such an optical filter may be provided as a single layer, or a plurality of optical filters may be stacked. Moreover, you may make such a filter function bear the transparent support bodies 30 thru | or 40 mentioned above. In the present invention, in addition to the optical filter, a layer having other functions such as a stain resistance function, an anti-scratch function, and an antistatic function may be laminated as the functional layer.
The conductive external light shielding material 100 of the present invention exhibits good shielding properties against electromagnetic waves in which the electric field vibrates (polarizes) in a direction parallel to the extending direction of the light shielding line 21, but the light shielding lines. There is little shielding against electromagnetic waves in which the electric field vibrates in the direction perpendicular to the direction in which the strips 21 extend. Therefore, the extending direction of the light-shielding filament 21 is grounded so as to be parallel to the electric field vibration direction (polarization direction) of the electromagnetic wave to be shielded.
In order to effectively shield (non-polarized) electromagnetic waves having electric field vibration components orthogonal to each other, two conductive external light shielding materials of the present invention are prepared, and the first and second light-shielding filaments 21 are prepared. It is preferable to laminate in such a direction that the extending directions of the two are orthogonal to each other.

  Further, when the front filter for an image display device is configured with the conductive external light shielding material of the present invention, the light shielding property of the conductive external light shielding material continuous in the extending direction is prevented in order to prevent image interference fringes (moire). It is preferable to arrange so that the angle formed between the filament and the pixel arrangement direction of the image display device is an angle other than 0 °, that is, not parallel. More specifically, when the intersection angle γ between the extension line of the light-shielding filament 21 and the pixel arrangement direction is a bias angle, it is preferable that the range is 5 ° <γ <80 °.

(Image display device)
FIG. 8 is a schematic diagram showing an example of the image display apparatus of the present invention. As shown in FIG. 8, the image display device 500 of the present invention includes the conductive external light shielding material 100, the conductive external light shielding material sheets 101 to 102, or the front filter 300 of the present invention. The bottom side of the light-shielding filament 21 having a trapezoidal shape or a substantially trapezoidal shape faces the front side of the viewer or the image display apparatus main body 400 at a position facing the front surface of the 400 image display unit. It is arranged in. By providing the front filter of the present invention, the image contrast in the presence of outside light can be improved.

  Examples of the image display device to be applied include a plasma panel display device (PDP), a cathode ray tube display device (CRT), a liquid crystal display device (LCD), and an electroluminescent display device (EL). It is suitable for an apparatus.

The conductive external light shielding material of the present invention can be applied to various uses. As a typical application, it can be effectively used alone or laminated with another functional layer as a constituent material of a front filter of an image display device having both functions of an electromagnetic wave shielding material and an image contrast enhancement filter.
The conductive external light shielding material sheet of the present invention is a constituent material for the front filter of an image display device having the functions of both an electromagnetic wave shielding material and an image contrast enhancement filter, like the conductive external light shielding material of the present invention. As such, it can be effectively used alone or laminated with other functional layers.
The front filter of the image display device of the present invention can be used as a relatively thin front filter for an image display device in combination with the electromagnetic wave shielding effect due to the conductivity of the conductive external light shielding material sheet.
Furthermore, the conductive external light wave shielding material of the present invention is a transparent antenna provided for window electromagnetic wave shielding filters such as windows for buildings, vehicles, ships, aircraft, or microwave ovens, cellular phones, etc. It can also be used for applications.

DESCRIPTION OF SYMBOLS 1 Metal particle 1 'Dark metal particle 1p Minute protrusion 1v Groove-shaped recessed part 2 Binder resin 3 Groove part 5 Groove part slope 10 Light-shielding linear pattern 20 Transparent resin layer (transparent base material)
21 Shading line (bottom bottom)
22 Translucent area (lens part)
23 concave part 24 light shielding line pattern upper bottom side 30 transparent support 40 transparent support 100 conductive external light shielding material 101 conductive external light shielding material support sheet 102 conductive external light shielding material support sheet of the second aspect Body 200 Functional layer 300 Front filter 400 Image display device body 500 Image display device E Exposed portion

Claims (4)

A conductive external light shielding material having a light shielding line pattern,
The light-shielding filament pattern is a trapezoidal or substantially trapezoidal light-shielding filament having a bottom that is continuous in the extending direction and whose cross section perpendicular to the extending direction has a wide bottom,
A light-transmitting region composed of a transparent resin layer connected at a predetermined gap between the light-shielding filaments is arranged,
The light-shielding filament is composed of metal particles and a binder resin,
And at least a part of the metal particles are exposed from the bottom side of the wide,
The exposed portion of the metal particles has a groove-like recess and a microprojection on its surface;
A conductive external light shielding material characterized by the above.   2. A conductive external light shielding material sheet comprising the conductive external light shielding material according to claim 1 and a transparent support.   2. A front filter for an image display device, comprising a functional layer laminated on the front surface and / or the back surface of the conductive external light shielding material according to claim 1.   An image display device comprising a front filter including the conductive external light shielding material according to claim 1 or the conductive external light shielding material sheet according to claim 2.