JP2008216734A - Filter for display and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter for display excellent in both of antidazzle characteristic and transparency. <P>SOLUTION: The filter for display includes: a stacked body 110 having a transparent substrate 111 and an electromagnetic wave shielding layer 112; and an antireflection layer 120 formed on the surface having the electromagnetic wave shielding layer 112 of the stacked body 110, wherein the surface of the antireflection layer 120 has protrusion parts formed by the electromagnetic wave shielding layer 112 and the surface roughness Ra of the antireflection layer 120 is 0.02-0.20 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display filter which has excellent antiglare properties and transparency and is used for a front filter such as a plasma display panel (PDP).

  Display devices such as liquid crystal displays (LCD), plasma displays (PDP), field emission displays (FED) and surface electric field displays (SED), flat panel displays (FPD) such as EL displays, and CRT displays Widely used. In recent years, large-screen displays have become mainstream in displays, and PDPs have become common as next-generation large-screen display devices.

  In recent years, large-screen displays have become mainstream in displays, and PDPs have become common as next-generation large-screen display devices. However, in this PDP, high-frequency pulse discharge is performed on the light emitting unit for image display, and there is a risk of unnecessary electromagnetic radiation and infrared radiation that may cause malfunction of an infrared remote controller or the like. For this reason, the conventional display is provided with a display filter having an electromagnetic wave shielding layer.

  Examples of the display filter having the electromagnetic wave shielding layer include: (1) a transparent film provided with a transparent conductive thin film containing metallic silver; and (2) a transparent provided with a conductive mesh made of a metal wire or conductive fiber in a net shape. Films, (3) A layer of copper foil or the like on a transparent film is etched into a net and an opening is provided, (4) A conductive ink is printed on a transparent film in a mesh, etc. ing.

  Moreover, since the visibility of the image displayed on the display will fall if the display surface is damaged, the display filter etc. which have a hard-coat layer are also known. Further, in a large display such as a conventional PDP, there is a problem that it is difficult to see an image displayed by reflection of a light beam irradiated from an external light source such as a fluorescent lamp. Therefore, a display filter having an antireflection layer is also widely used.

  The electromagnetic wave shielding layer, the hard coat layer, and the antireflection layer are laminated and used according to the use of the display filter. For example, Patent Document 1 discloses a display filter in which an electromagnetic wave shielding layer, a hard coat layer, and an antireflection layer are laminated in this order on a transparent substrate.

  Patent Document 2 includes a transparent substrate, a mesh-shaped electromagnetic wave shielding layer formed on the transparent substrate and having a large number of light transmission parts, and a transparent resin that covers the electromagnetic wave shielding layer and the light transmission parts. A display filter having a cured coating film is disclosed. In the filter for display of patent document 2, it is disclosed that the average inclination | tilt angle of the protruding part formed of the electromagnetic wave shielding layer among hardened coating films shall be 10 degrees or less. It has been disclosed that by forming such a flattened layer by a cured coating film, a decrease in light transmittance due to irregular reflection of light of the electromagnetic wave shielding layer is prevented. Furthermore, in Patent Document 2, in order to obtain a display filter having high light transmittance and high image definition, the ten-point average roughness (Rz) of the surface of the cured coating film is 0.05 to 7 μm, particularly 0.1 to 5 μm. (Paragraph “0056”), and in the examples, a cured coating film having a surface ten-point average roughness (Rz) of 1.3 to 4.3 μm is produced.

JP 2004-163752 A JP 2006-210527 A

  Conventional display filters are further desired to have antiglare properties. That is, when the display is used indoors, there is a problem that it becomes difficult to recognize characters and the like due to the illumination of a fluorescent lamp or the like, so that it further has a high anti-glare property to prevent the reflection of the external environment. Is desired.

  In order to impart anti-glare properties to the display filter, means for diffusing external light by providing an uneven shape on the surface of the layer disposed on the outermost surface of the display filter is useful.

  However, in order to obtain a high antiglare property, for example, by using a means such as simply increasing the content of refractive index adjusting particles such as silica and imparting an uneven shape to the surface of the hard coat layer, the antireflection layer There was a possibility that the haze of the glass would be lowered and sufficient transparency could not be secured.

  In addition, the display filter of Patent Document 2 has a cured coating film having a raised portion formed by an electromagnetic wave shielding layer. However, the cured coating film is used to prevent a decrease in light transmittance due to irregular reflection of light from the electromagnetic shielding layer. It has been disclosed that a flat surface is desirable, and it has been difficult to obtain a display filter having sufficient antiglare property and transparency.

  As described above, in order to improve the visibility of a display image, it is necessary to obtain a high anti-glare property without lowering the transparency. However, it has been difficult to realize a display filter having both of them. It was.

  Therefore, an object of the present invention is to provide a display filter that is excellent in both antiglare property and transparency.

  Furthermore, an object of this invention is to provide the manufacturing method of the filter for displays which is excellent in both anti-glare property and transparency.

  In order to obtain the high antiglare property of the display filter, it is effective to use means for imparting an uneven shape to the surface of the layer disposed on the outermost surface of the display filter as described above. As a result of various studies in view of such knowledge, the present inventor formed a mesh-like electromagnetic wave shielding layer on a transparent substrate, and provided a predetermined surface roughness Ra on the transparent substrate having the electromagnetic wave shielding layer. It has been found that a display filter having high antiglare property can be obtained without lowering transparency by forming a hard coat layer.

That is, the present invention has a laminate having a transparent substrate and a mesh-like electromagnetic shielding layer, and a hard coat layer formed on the surface of the laminate having the electromagnetic shielding layer,
The above problem is solved by a display filter, wherein the hard coat layer has a surface roughness Ra of 0.02 to 0.20 μm.

  According to the present invention, by forming a hard coat layer having a predetermined surface roughness on an electromagnetic wave shielding layer, it is possible to provide a display filter that is excellent in both antiglare property and transparency with a simple configuration. It becomes. Therefore, the display filter is excellent in the visibility of the image displayed on the display, and is useful as a display filter attached to the surface of an optical article such as a plasma display panel (PDP) or an EL display.

  First, the display filter of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view of a display filter of the present invention.

  The display filter of the present invention has a transparent substrate 111, a laminate 110 having a mesh-like electromagnetic shielding layer 112 formed on the transparent substrate 111, and further on the surface of the laminate 110 having the electromagnetic shielding layer 112. Has a hard coat layer 120.

  The hard coat layer has an uneven shape so that the surface roughness Ra is 0.02 to 0.20 μm. In this way, by forming an uneven shape so as to have a predetermined roughness on the hard coat layer, a hard coat layer excellent in antiglare property that can diffuse reflected light highly without reducing transparency, and It becomes possible to do. Therefore, the display filter can prevent the reflection of the external environment on the display filter.

  In the display filter of the present invention, the hard coat layer has a surface roughness Ra of 0.02 to 0.20 μm, preferably 0.05 to 0.20 μm. If the surface roughness Ra of the hard coat layer is less than 0.02, it may not be possible to obtain a hard coat layer having sufficient antiglare properties, and if it exceeds 0.20 μm, sufficient antiglare properties cannot be obtained. Furthermore, the image displayed on the display may be greatly diffused and the transparency (haze) may deteriorate.

  Furthermore, the display filter of the present invention has a configuration in which a hard coat layer is formed on a laminate having a mesh-like electromagnetic wave shielding layer. As a result, as shown in FIG. 1, a raised portion formed by the electromagnetic wave shielding layer is formed on the surface of the hard coat layer, that is, an uneven shape corresponding to the mesh-like uneven shape formed by the electromagnetic wave shielding layer. The surface roughness of the hard coat layer can be adjusted by a simple means without reducing the transparency of the hard coat layer.

  In order to make the surface roughness within the above-mentioned predetermined range without reducing the transparency of the hard coat layer, the surface roughness Ra of the surface on which the electromagnetic wave shielding layer of the laminate is formed is 0.1 to 7. It is preferably 0 μm, more preferably 0.1 to 3.0 μm, and particularly preferably 0.3 to 2.5 μm.

  The transparent substrate used in the laminate is not particularly limited as long as it has transparency and flexibility and can withstand subsequent processing. Examples of the material of the transparent substrate include glass, polyester (eg, polyethylene terephthalate, (PET), polybutylene terephthalate), acrylic resin (eg, polymethyl methacrylate (PMMA)), polycarbonate (PC), polystyrene, cellulose triacetate, Polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane, etc. PET, PC, and PMMA, which are less transparent due to processing (heating, solvent, bending) and are highly transparent, are preferable. The transparent substrate is used as a sheet, film, or plate made of these materials.

  The thickness of the transparent substrate is not particularly limited, but is preferably about 6 to 250 μm.

  In the laminate, the meshed electromagnetic wave shielding layer formed on the transparent substrate includes (1) a metal fiber and a metal-coated organic fiber, (2) a metal such as copper, and (3) a binder resin. Examples include those in which conductive particles are dispersed.

  (1) In the electromagnetic wave shielding layer composed of metal fibers and metal-coated organic fibers, the metals of the metal fibers and metal-coated organic fibers include copper, stainless steel, aluminum, nickel, titanium, tungsten, tin, lead, iron, silver, carbon Alternatively, these alloys, preferably copper, stainless steel and nickel are used.

  As the organic material for the metal-coated organic fiber, polyester, nylon, vinylidene chloride, aramid, vinylon, cellulose and the like are used. The metal-coated organic fiber is obtained by coating these organic fibers with the metal.

  (2) In the electromagnetic wave shielding layer made of a metal such as copper, copper, stainless steel, aluminum, nickel, iron, brass, or an alloy thereof, preferably copper, stainless steel, or aluminum is used as the metal.

  (3) In the electromagnetic wave shielding layer in which conductive particles are dispersed in a binder resin, examples of the conductive particles include aluminum, nickel, indium, chromium, gold, vanadium, tin, cadmium, silver, platinum, copper, Metals, alloys such as titanium, cobalt, lead; or indium oxide, tin oxide, zinc oxide, indium oxide-tin oxide (ITO, so-called indium-doped tin oxide), tin oxide-antimony oxide (ATO, so-called antimony-doped tin oxide) And conductive oxides such as zinc oxide-aluminum oxide (ZAO; so-called aluminum-doped zinc oxide). In particular, ITO is preferable.

  Examples of the binder resin include acrylic resin, polyester resin, epoxy resin, urethane resin, phenol resin, maleic acid resin, melamine resin, urea resin, polyimide resin, and silicon-containing resin. Furthermore, it is preferable that it is a thermosetting resin among these resins.

  The shape of the mesh pattern in the electromagnetic wave shielding layer is not particularly limited, and examples thereof include a lattice shape in which square openings are formed, and a punching metal shape in which circular, hexagonal, triangular or elliptical openings are formed. It is done. Further, the openings are not limited to those regularly arranged, and may be a random pattern. Since high electromagnetic shielding properties and visibility can be obtained, the mesh pattern in the electromagnetic shielding layer preferably has a lattice shape in which openings are regularly arranged.

  In order to adjust the surface roughness Ra of the surface on which the electromagnetic wave shielding layer of the laminate is formed within a predetermined range, it is preferable to adjust the mesh shape of the electromagnetic wave shielding layer. Thereby, the raised part and surface roughness of a hard-coat layer can be adjusted easily.

  As the mesh in the mesh-shaped electromagnetic wave shielding layer, those having a line width of 1 μm to 15 μm and an aperture ratio of 75 to 95% are preferable. A more preferable line width is 1 μm to 10 μm, and an aperture ratio is 80 to 95%. When the line width exceeds 15 μm in the mesh-shaped electromagnetic wave shielding layer, the electromagnetic wave shielding property is improved, but the hard coat layer surface cannot be provided with an appropriate surface roughness and has a sufficient antiglare property. There is a possibility that the layer cannot be formed. On the other hand, if the line width is less than 1 μm, the strength as a mesh is lowered and handling becomes difficult. Further, when the aperture ratio exceeds 95%, it is difficult to maintain the shape as a mesh, and when it is less than 75%, an appropriate surface roughness cannot be imparted to the surface of the hard coat layer, and sufficient antiglare properties are obtained. There is a possibility that the hard coat layer having the above cannot be formed.

  The aperture ratio of the electromagnetic wave shielding layer refers to the area ratio occupied by the opening portion in the projected area of the electromagnetic wave shielding layer.

  The thickness of the electromagnetic wave shielding layer is 0.01 to 10 μm, particularly 0.05 to 3 μm from the viewpoint of adjusting the surface roughness Ra of the surface of the laminate on which the electromagnetic wave shielding layer is formed within a predetermined range. Is preferable.

  The hard coat layer in the display filter of the present invention only needs to have an uneven shape having a predetermined surface roughness Ra. In order to adjust the surface roughness of the hard coat layer within the above-mentioned range, in addition to adjusting the surface roughness of the electromagnetic shielding base material, particles having a predetermined average particle diameter are further dispersed in the hard coat layer. Means and the like are preferably used. According to such means, the surface roughness Ra of the hard coat layer can be easily adjusted. Furthermore, by forming a hard coat layer on an electromagnetic wave shielding base material having an electromagnetic wave shielding layer, the surface roughness Ra is set within the above-described range without dispersing a large amount of the particles in the antireflection layer. And high transparency of the hard coat layer can be secured.

  Therefore, the hard coat layer is preferably a cured layer in which particles having an average particle diameter of 0.01 to 1 μm are dispersed in a curable resin. If it is such a hardened layer, it is possible to easily adjust the surface roughness of the hard coat layer within the above range by imparting irregularities with an appropriate roughness, and the hard coat layer is excellent in transparency and antiglare properties. Can be formed.

  The curable resin is not particularly limited, and examples thereof include polyfunctional (meth) acrylates, epoxy-based, and oxetane-based curable resins that can be polymerized by heat, active light, radiation, or the like. Of these, polyfunctional (meth) acrylates are preferred.

  The polyfunctional (meth) acrylate is not particularly limited. For example, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol (meth) tetraacrylate, dipentaerythritol tri (meth) acrylate , Pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, etc. Is mentioned.

  As the polyfunctional (meth) acrylate, it is possible to form a hard coat layer that has excellent hard coat properties and is difficult to be scratched, so that the hydroxyl group-containing (meth) acrylate is at least 15 masses based on the total amount of the curable resin. %, Particularly 20 to 30% by mass is preferable.

  The hydroxyl group-containing (meth) acrylate is preferably 2-hydroxy-3-acryloyloxypropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxyisopropyl ( (Meth) acrylate, 2-hydroxybutyl (meth) acrylate, propylene glycol mono (meth) acrylate, ethylene glycol mono (meth) acrylate, (poly) alkylene glycol monoacrylate, and monomers and lactones thereof (for example, ε-caprolactone) Etc.), for example, caprolactone-modified 2-hydroxyethyl (meth) acrylate and the like.

  Thus, it becomes possible to form the hard-coat layer which has high hardness by using polyfunctional (meth) acrylate. Specifically, it becomes possible to form a hard coat layer having a hardness of 3H or more by a pencil scratch test method defined in JIS K 5400.

  In the present invention, “(meth) acrylate” means “acrylate or methacrylate”.

  The hard coat layer includes particles having an average particle diameter of preferably 0.01 to 1 μm, more preferably 0.01 to 0.1 μm, in the curable resin described above. The average particle diameter of the particles is a number average obtained by observing the cross section of the display filter with an electron microscope (preferably a transmission electron microscope) at a magnification of about 1,000,000, and determining the area equivalent circle diameter of at least 100 particles. Value.

  The content of the particles in the hard coat layer is preferably 10 to 900 parts by mass, more preferably 500 to 800 parts by mass with respect to 100 parts by mass of the curable resin. Thereby, moderate surface roughness can be given to a hard-coat layer, without reducing transparency.

  The hard coat layer preferably has a higher refractive index than the transparent substrate in order to obtain high antireflection properties. The refractive index of the hard coat layer is preferably 1.49 to 1.80, particularly preferably 1.70 to 1.80.

In order to increase the refractive index of the hard coat layer as described above, particles having a high refractive index are preferably used as the particles used in the hard coat layer. For example, metal oxide particles such as ITO, TiO ₂ , ZrO ₂ , CeO ₂ , Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , LaO _2, and Ho ₂ O ₃ are used. These may be used individually by 1 type, and may mix and use 2 or more types.

  The thickness of the hard coat layer is preferably 3.0 to 10 μm, more preferably 6.5 to 7 μm, in order to obtain a predetermined surface roughness.

  In order to further improve the antireflection property, the display filter of the present invention may have a low refractive index layer having a refractive index lower than that of the hard coat layer on the hard coat layer. The refractive index of the low refractive index layer may be in the range of 1.20 to 1.50, particularly 1.25 to 1.45.

  As described above, the display filter of the present invention has a hard coat layer having excellent transparency and antiglare properties, and sufficient antireflection properties can be obtained by making the refractive index of the hard coat layer higher than that of the transparent substrate. Therefore, even if it does not have a low refractive index layer, it has high antireflection properties.

As the low refractive index layer, a known layer such as a cured layer in which particles such as SiO ₂ , MgF ₂ , Al ₂ O ₃ , silica, and fluorine resin are dispersed in a curable resin is used.

  As the particles, it is preferable to use hollow silica. The hollow silica has an average particle diameter of 10 to 100 nm, preferably 10 to 50 nm, and a specific gravity of 0.5 to 1.0, preferably 0.8 to 0.9. In addition, as the curable resin, the same one as described above in the hard coat layer is used.

  The thickness of the low refractive index layer is usually 10 to 500 nm, preferably 20 to 200 nm.

  As described above, the display filter of the present invention can impart antiglare properties to the hard coat layer without degrading transparency by imparting a predetermined surface roughness. Therefore, the display filter having the hard coat layer is also highly transparent and has a low haze value. Specifically, the haze of the display filter having the hard coat layer described above is 7.0% or less, particularly 3.0% or less.

  Furthermore, in the display filter of the present invention, it is preferable that the laminate further has a near-infrared absorbing layer on the surface opposite to the surface on which the electromagnetic wave shielding layer is formed. As a result, it is possible to prevent the infrared radiation that causes the display filter to cause a malfunction of the infrared remote controller or the like.

  The near-infrared absorbing layer (that is, the near-infrared shielding layer) is generally obtained by forming a layer containing a pigment or the like on the surface of the transparent substrate in the laminate. The near-infrared absorbing layer can be obtained by applying, if necessary, drying and curing a coating solution containing an ultraviolet curable or electron beam curable synthetic resin containing a pigment and a synthetic resin as a binder. When used as a film, it is generally a near-infrared cut film, such as a film containing a pigment or the like.

  The dye generally has an absorption maximum at a wavelength of 800 to 1200 nm. Examples include phthalocyanine dyes, metal complex dyes, nickel dithiolene complex dyes, cyanine dyes, squarylium dyes, polymethine dyes, Examples thereof include azomethine dyes, azo dyes, polyazo dyes, diimonium dyes, aminium dyes, and anthraquinone dyes, and cyanine dyes or squarylium dyes are particularly preferable. These dyes can be used alone or in combination.

  As examples of the synthetic resin as the binder, acrylic resin, fluororesin, polyester resin, vinyl chloride resin, styrene resin, norbornene resin, and the like are preferably used. These may be used individually by 1 type and may be used in mixture of 2 or more types.

  In the present invention, the near-infrared absorbing layer may be provided with a function of adjusting color tone by providing a function of absorbing neon light emission. For this purpose, a neon-emission absorption layer may be provided, but a neon-emission selective absorption dye may be included in the near-infrared absorption layer.

  Examples of selective absorption dyes for neon emission include cyanine dyes, squarylium dyes, anthraquinone dyes, phthalocyanine dyes, polymethine dyes, polyazo dyes, azurenium dyes, diphenylmethane dyes, and triphenylmethane dyes. it can. Such a selective absorption dye is required to have a selective absorption of neon emission near 585 nm and a small absorption at other visible light wavelengths, so that the absorption maximum wavelength is 575 to 595 nm and the absorption spectrum half width is What is 40 nm or less is preferable.

  Also, when combining multiple types of near-infrared or neon luminescent absorbing dyes, if there is a problem with the solubility of the dye, if there is a reaction between the dyes due to mixing, if there is a decline in heat resistance, moisture resistance, etc. All the near-infrared absorbing dyes need not be contained in the same layer, and may be contained in another layer.

  Further, as long as the optical properties are not greatly affected, coloring pigments, ultraviolet absorbers, antioxidants and the like may be further added.

  As a near-infrared absorption characteristic of the display filter of the present invention, it is preferable that the transmittance at 850 to 1000 nm is 20% or less, and further 15%. Moreover, as selective absorptivity, it is preferable that the transmittance | permeability of 585 nm is 50% or less. Especially in the former case, there is an effect of reducing the transmittance in a wavelength region where malfunction of a remote controller of a peripheral device is pointed out. In the latter case, an orange color having a peak at 575 to 595 nm is color reproducibility. This has the effect of absorbing the orange wavelength, thereby improving the redness and improving the color reproducibility.

  The thickness of the near-infrared absorbing layer is not particularly limited, but is preferably about 0.5 to 50 μm in terms of near-infrared absorption and visible light transmission.

  It is preferable that the near-infrared absorbing layer contains a color correction pigment. Alternatively, a color tone correction layer containing a color tone correction pigment may be provided in the same manner as the near infrared absorption layer.

  As the color correction pigment, in order to neutralize the yellowish brown to green color tone of the near-infrared shielding layer and adjust the color balance, those which are complementary colors thereof are preferable. Examples of such pigments include general pigments such as inorganic pigments, organic pigments, organic dyes, and pigments. Examples of inorganic pigments include cobalt compounds, iron compounds, chromium compounds, and examples of organic pigments include azo-based, indolinone-based, quinacridone-based, vat-based, phthalocyanine-based, naphthalocyanine-based, Examples of the organic dyes and pigments include azo, azine, anthraquinone, indigoid, oxazine, quinophthalone, squalium, stilbene, triphenylmethane, naphthoquinone, pyrarozone, and polymethine. Of these, organic pigments are preferably used in view of the balance between color developability and durability.

  In the display filter of the present invention, it is preferable to further have a transparent pressure-sensitive adhesive layer on the above-mentioned near-infrared absorbing layer. The transparent adhesive layer makes it possible to easily bond the display filter of the present invention to an image display glass plate of the display.

  The transparent adhesive layer is a layer for adhering to the display, and any resin can be used as long as it has an adhesive function. Examples of the resin having an adhesive function in the transparent adhesive layer include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer, acrylic resin (eg, ethylene- (meth) acrylic acid copolymer). , Ethylene- (meth) acrylic acid ethyl copolymer, ethylene- (meth) methyl acrylate copolymer, metal ion crosslinked ethylene- (meth) acrylic acid copolymer), partially saponified ethylene-vinyl acetate copolymer, Examples include ethylene-based copolymers such as carboxylated ethylene-vinyl acetate copolymer, ethylene- (meth) acryl-maleic anhydride copolymer, ethylene-vinyl acetate- (meth) acrylate copolymer (note that And “(meth) acryl” means “acryl or methacryl”.) In addition, polyvinyl butyral (PVB) resin, epoxy resin, phenol resin, silicone resin, polyester resin, urethane resin, rubber adhesive, SEBS (styrene / ethylene / butylene / styrene), SBS (styrene / butadiene / styrene), etc. Thermoplastic elastomers and the like can also be used, but it is acrylic resin-based pressure-sensitive adhesives and epoxy resins that can easily obtain good adhesiveness.

  The thickness of the transparent adhesive layer is generally 10 to 50 μm, preferably 20 to 30 μm. In general, the display filter can be equipped by heat-pressing the pressure-sensitive adhesive layer to a glass plate of the display.

  In addition, the transparent adhesive layer according to the present invention may contain a small amount of an ultraviolet absorber, an infrared absorber, an anti-aging agent, a coating processing aid, a colorant and the like. Further, a small amount of a filler such as hydrophobic silica and calcium carbonate may be included.

  It is preferable that a release sheet is further provided on the transparent adhesive layer. As a material for the release sheet, a transparent polymer having a glass transition temperature of 50 ° C. or higher is preferable. Examples of such a material include polyester resins such as polyethylene terephthalate, polycyclohexylene terephthalate, and polyethylene naphthalate, nylon 46, and modified nylon. In addition to polyamide resins such as 6T, nylon MXD6 and polyphthalamide, ketone resins such as polyphenylene sulfide and polythioether sulfone, and sulfone resins such as polysulfone and polyether sulfone, polyether nitrile, polyarylate, poly Resins based on polymers such as ether imide, polyamide imide, polycarbonate, polymethyl methacrylate, triacetyl cellulose, polystyrene and polyvinyl chloride can be used. . Of these, polycarbonate, polymethyl methacrylate, polyvinyl chloride, polystyrene, and polyethylene terephthalate can be suitably used. The thickness is preferably 10 to 200 μm, particularly preferably 30 to 100 μm.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to obtain the display filter which has a hard-coat layer which is excellent in both anti-glare property and transparency. Such an optical filter for display of the present invention is used by being bonded to the surface of a glass plate for image display of a display such as PDP by pressure bonding or the like.

  Since the PDP display device of the present invention uses a plastic film or the like as a transparent substrate, the display filter of the present invention can be directly bonded to the surface of the image display glass plate. Contributes to reduction in size, thickness and cost. Compared with the case where a front plate made of a transparent molded body is installed on the front side of the PDP, an air layer having a low refractive index can be eliminated between the PDP and the PDP filter, so that visible light reflection due to interface reflection can be achieved. Problems such as an increase in rate and double reflection can be solved, and the visibility of the PDP can be further improved.

  In addition to the plasma display panel (PDP), the display includes a field emission display (FED) including a surface electric field display (SED), a flat panel display (FPD) such as a liquid crystal display (LCD), an EL display, etc. , And a CRT display.

  Next, the manufacturing method of the display filter of the present invention described above will be described. In the method, the surface roughness Ra is 0.02 to 0.20 μm by applying a hard coat layer forming ink containing a curable resin on a laminate having a transparent substrate and a mesh-like electromagnetic wave shielding layer. A method for producing a display filter, comprising a step of forming a hard coat layer, wherein the viscosity of the hard coat layer forming ink is 10 to 5000 cP or less at 25 ° C. According to such a method, the electromagnetic wave shielding layer of the present invention described above can be easily produced.

  The laminate has a transparent substrate and an electromagnetic wave shielding layer formed on the transparent substrate. In order to form the electromagnetic shielding layer on the transparent substrate, a conventionally known means may be used.

  When using an electromagnetic wave shielding layer made of (1) metal fibers and metal-coated organic fibers, for example, a metal fiber and metal-coated organic fibers made of mesh-like metal are prepared, and then this is coated on a transparent substrate. A method of bonding using an adhesive resin layer or the like is used. Although it does not restrict | limit especially as said adhesive resin, For example, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ethyl copolymer Polymer, ethylene- (meth) acrylic acid methyl copolymer, metal ion crosslinked ethylene- (meth) acrylic acid copolymer, partially saponified ethylene-vinyl acetate copolymer, carboxylated ethylene-vinyl acetate copolymer, ethylene- Examples thereof include ethylene-based copolymers such as (meth) acryl-maleic anhydride copolymer and ethylene-vinyl acetate- (meth) acrylate copolymer.

  When using an electromagnetic shielding layer made of a metal such as (2) copper, first, a vapor deposition method such as sputtering, ion plating, electron beam deposition, vacuum deposition, chemical vapor deposition, printing, A metal foil is formed on the transparent substrate using a method such as coating. Then, an electromagnetic wave shielding layer can be formed on a transparent substrate by forming the predetermined opening by etching the metal foil according to a known method.

  In addition to the above, as a mesh-like electromagnetic shielding layer, dots are formed on a transparent substrate with a material soluble in a solvent, and a conductive material layer made of a conductive material insoluble in a solvent is formed on the film surface Then, a mesh-like electromagnetic shielding layer obtained by contacting the film surface with a solvent and removing the dots and the conductive material layer on the dots may be used. Such a method is described in, for example, Japanese Patent Application Laid-Open No. 2001-332889.

  In addition, when (3) a conductive resin dispersed in a binder resin is used as the electromagnetic shielding layer, a method of printing a conductive ink containing a binder resin and conductive particles on a transparent substrate in a mesh form is used. It is done.

  In addition to the conductive particles and the binder resin, the conductive ink may further contain a solvent in order to adjust to an appropriate viscosity. Examples of the solvent include alcohols such as hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, stearyl alcohol, seryl alcohol, cyclohexanol, terpineol; ethylene glycol monobutyl ether (butyl cellosolve), ethylene Examples thereof include alkyl ethers such as glycol monophenyl ether, diethylene glycol, diethylene glycol monobutyl ether (butyl carbitol), cellosolve acetate, butyl cellosolve acetate, carbitol acetate, and butyl carbitol acetate.

  In order to print the conductive ink in a mesh on the transparent substrate, a known method such as gravure printing, flexographic printing, gravure offset printing, screen printing, ink jet printing, or electrostatic printing may be used. Then, it is made to dry and harden at room temperature-120 degreeC as needed.

  By further performing electroless plating and / or electroplating, it is possible to increase the thickness of the obtained electromagnetic wave shielding layer and improve conductivity.

  In the present invention, the surface roughness Ra of the surface on which the electromagnetic wave shielding layer of the laminate is formed is 0.1 to 7.0 μm, more preferably 0.1 to 3.0 μm, particularly 0.3 to 2.5 μm. Is preferred. Thereby, surface roughness can be made into the range of 0.02-0.20 micrometer, without reducing the transparency of a hard-coat layer. For this purpose, it is preferable to adjust the mesh shape in the electromagnetic wave shielding layer of the laminate.

  In the method of the present invention, a hard coat layer is formed by applying a hard coat layer forming ink containing a curable resin on the laminate produced as described above. As the ink for forming the hard coat layer, ink having a viscosity of 10 cP to 5000 cP or less, particularly 50 cP to 500 cP at 25 ° C. is used. Thereby, it is possible to form a hard coat layer having an uneven shape formed by the electromagnetic wave shielding layer on the surface and having a surface roughness of 0.02 to 0.20 μm, particularly 0.05 to 0.20 μm. Become.

Examples of the curable resin used in the hard coat layer forming ink include polyfunctional (meth) acrylate, epoxy-based, and oxetane-based curable resins. Of these, polyfunctional (meth) acrylates are preferred. Furthermore, as the polyfunctional (meth) acrylate, a hard coat layer having excellent hard coat properties and being hardly scratched can be formed, so that the hydroxyl group-containing (meth) acrylate is at least 15 with respect to the total amount of the curable resin. It is preferable that the content is 20% by mass, particularly 20 to 30% by mass. In addition, since it is the same as that mentioned above in the filter for a display of this invention about curable resin, detailed description is abbreviate | omitted here.

  In addition to the curable resin, the hard coat layer forming ink has an average of 0.01 to 1 μm, more preferably 0.01 to 0.1 μm, in order to adjust the surface roughness Ra and refractive index of the hard coat layer. It is preferable to further include particles having a particle size.

  The content of the particles in the hard coat layer forming ink is preferably 10 to 900 parts by mass, more preferably 500 to 800 parts by mass with respect to 100 parts by mass of the curable resin. Thereby, the hard-coat layer which has moderate surface roughness can be formed, without transparency falling.

  In addition, since what is concrete as said particle | grain is the same as that of what was mentioned above in the filter for a display of this invention, detailed description is abbreviate | omitted here.

  In addition to the curable resin and the particles, the hard coat layer forming ink may further contain a solvent. As the solvent, the same solvent as that used in the conductive ink for forming the electromagnetic wave shielding layer is used. The concentration of the solvent is usually 80% by mass or less, preferably 10 to 70% by mass.

  The hard coat layer forming ink may further contain various known additives such as a polymerization initiator, a sensitizer, an antifoaming agent, a leveling agent, and an antioxidant as necessary.

  As the polymerization initiator, any compound suitable for the properties of the curable resin can be used. For example, acetophenone such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1 Benzoin series such as benzyl dimethyl ketal, benzophenone, 4-phenylbenzophenone, benzophenone series such as hydroxybenzophenone, thioxanthone series such as isopropylthioxanthone, 2-4-diethylthioxanthone, and other special types include methylphenyl glyoxylate Etc. can be used. Particularly preferably, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1, Examples include benzophenone. These polymerization initiators are optionally mixed with one or two or more of known and commonly used polymerization accelerators such as benzoic acid series such as 4-dimethylaminobenzoic acid or tertiary amine series. Can be used as a mixture. Moreover, it can be used by the mixture of 1 type, or 2 or more types only of a polymerization initiator. Particularly preferred is 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals).

  The quantity of a polymerization initiator is 0.1-10 mass parts with respect to 100 mass parts of curable resin, Preferably it is 0.1-5 mass parts.

  To apply the hard coat layer forming ink on the laminate, wire bar coating method, roll coating method, spray coating method, extrusion coating method, curtain coating method, dip coating method, spin coating method, gravure coating method, etc. Any known coating method may be used.

  The hard coat layer forming ink applied on the laminate is then dried and, if necessary, heat-cured, or after coating, if necessary, dried and irradiated with ultraviolet rays.

  The drying may be usually performed at room temperature to about 250 ° C. Moreover, when irradiating with ultraviolet rays, many light sources that emit light in the ultraviolet to visible range can be used as the light source, for example, ultra-high pressure, high pressure, low pressure mercury lamp, chemical lamp, xenon lamp, halogen lamp, mercury lamp, carbon arc lamp. , Incandescent lamps, laser light, and the like. The irradiation time cannot be determined unconditionally depending on the type of lamp and the intensity of the light source, but is about several seconds to several minutes.

In the case of forming the low refractive index layer on the hard coat layer, in place of the particles having an average particle size of _{0.001~2μm, SiO 2, MgF 2,} Al 2 O 3, silica, fluorocarbon resin, etc. A method similar to the method for forming the hard coat layer described above may be used except that the above particles are used.

  What is necessary is just to perform using a well-known method, when producing a near-infrared absorption layer and a transparent adhesive layer. For example, in order to produce a near-infrared absorbing layer, a method of applying, if necessary, drying and curing a coating solution containing an ultraviolet curable or electron beam curable synthetic resin containing a synthetic resin as a pigment and a binder Etc. can be used. In order to produce a transparent adhesive layer, for example, EVA and the above-mentioned additives are mixed, kneaded with an extruder, a roll, etc., and then predetermined by a film forming method such as a calendar, roll, T-die extrusion, inflation, etc. For example, a method of forming a sheet into a shape can be used.

  Hereinafter, the present invention will be described with reference to examples. The present invention is not limited by the following examples.

(Example 1)
1. Preparation of Laminate Water-soluble ink (30% by mass) having the following composition was printed in a dot shape on a PET film (thickness 250 μm, S grade; manufactured by Teijin Ltd.) by screen printing. Based on the design with an aperture ratio of 85%, a dot pattern was printed in which the size of one dot was a square shape with one side of 165 μm, the interval between dots was 32 μm, and the dots were regularly arranged in a square lattice pattern. The printing thickness is 2 μm after drying.

Composition of water-soluble ink:
20 parts by weight of polyvinyl alcohol (in solid content)
(Polymerization degree 500, saponification degree 88%, Kuraray Co., Ltd. PVA205)
Barium sulfate (average particle size 2 μm) 10 parts by mass Water / methanol = 1/4 (mass ratio) 70 parts by mass Copper was vacuum-deposited thereon so that the average film thickness was 100 nm. Next, it was immersed in room temperature water and rubbed with a sponge to dissolve and remove the dot portion, then rinsed with water and dried to form a mesh (lattice) pattern.

  Thereafter, the copper film was subjected to electro copper plating at 30 ° C. in a copper sulfate bath composed of copper sulfate pentahydrate: 200 g / L, sulfuric acid: 50 g / L, and hydrochloric acid: 20 g / L. The test was performed for 10 minutes under the condition of 20A. As an adherend (cathode), a copper plate having a size of 600 × 1000 mm was used, and a copper ball with a titanium case was used as an anode.

  Thus, a laminate in which a mesh-like electromagnetic shielding layer was formed on the PET film was obtained. The electromagnetic wave shielding layer has a square lattice shape that accurately corresponds to a negative pattern of dots, has a square-shaped opening with a thickness of 3.3 μm, a line width of 32 μm, and a side of 165 μm, and an aperture ratio Was 70%. Further, the surface roughness Ra of the surface on which the electromagnetic wave shielding layer of the laminate was formed was 1.1 μm.

2. Preparation of Hard Coat Layer A hard coat layer forming ink (viscosity: 25 ° C., 50 cP) having the following composition is made to have a thickness of about 12 μm using a bar coater on the surface of the laminate on which the electromagnetic wave shielding layer is formed. And dried in an oven at 80 ° C. for 1 minute, and then cured by irradiating with an ultraviolet ray having an accumulated light amount of 2400 mJ / cm ² . As a result, a display filter having a hard coat layer (thickness: 6.9 μm) on the laminate was produced.

Composition of hard coat layer forming ink:
2-hydroxy-3-acryloyloxypropyl methacrylate 24 parts by mass Dipentaerythritol hexaacrylate 16 parts by mass TiO ₂ particles (average particle size 0.1 μm) 4 parts by mass Polymerization initiator (Irquagua 184, manufactured by Ciba Specialty Chemicals) 6 Parts by mass Isopropyl alcohol (IPA) 30 parts by mass Methyl ethyl ketone (MEK) 10 parts by mass Cyclohexanone (CAN) 10 parts by mass

(Example 2)
A display filter was produced in the same manner as in Example 1 except that the content of TiO ₂ particles in the hard coat layer forming ink was 15 parts by mass and the viscosity of the hard coat layer forming ink was 60 cP at 25 ° C. .

(Example 3)
In the hard coat layer forming ink, the content of 2-hydroxy-3-acryloyloxypropyl methacrylate is 16 parts by mass, the content of dipentaerythritol hexaacrylate is 24 parts by mass, and the viscosity of the hard coat layer forming ink is A display filter was produced in the same manner as in Example 1 except that 110 cP was used at 25 ° C.

Example 4
In the hard coat layer forming ink, the content of 2-hydroxy-3-acryloyloxypropyl methacrylate is 20 parts by mass, the content of dipentaerythritol hexaacrylate is 20 parts by mass, and the content of TiO ₂ particles is 10 parts by mass. A display filter was prepared in the same manner as in Example 1 except that the viscosity of the hard coat layer forming ink was 65 cP at 25 ° C.

(Comparative Example 1)
In the hard coat layer forming ink, the viscosity of the hard coat layer forming ink is 25 by setting the content of 2-hydroxy-3-acryloyloxypropyl methacrylate to 4 parts by mass and the content of IPA to 60 parts by mass. A display filter was produced in the same manner as in Example 1 except that the temperature was set to 8 cP at 8 ° C. and the thickness of the hard coat layer was set to 2.2 μm.

(Comparative Example 2)
In the hard coat layer forming ink, the content of 2-hydroxy-3-acryloyloxypropyl methacrylate is 10 parts by mass, the content of dipentaerythritol hexaacrylate is 30 parts by mass, and the content of TiO ₂ particles is 20 parts by mass. A display filter was prepared in the same manner as in Example 1 except that the viscosity of the hard coat layer forming ink was 120 cP at 25 ° C.

(Comparative Example 3)
In the hard coat layer forming ink, the content of 2-hydroxy-3-acryloyloxypropyl methacrylate is 4 parts by mass, the content of dipentaerythritol hexaacrylate is 36 parts by mass, and the content of TiO ₂ particles is 50 parts by mass. A display filter was prepared in the same manner as in Example 1 except that the viscosity of the hard coat layer forming ink was changed to 130 cP at 25 ° C.

(Comparative Example 4)
In the hard coat layer forming ink, instead of 2-hydroxy-3-acryloyloxypropyl methacrylate and dipentaerythritol hexaacrylate, 20 parts by mass of polypropylene glycol # 400 diacrylate (manufactured by Hitachi Chemical Co., Ltd.) and neopentyl A display filter was produced in the same manner as in Example 1, except that 20 parts by mass of glycol diacrylate was used, TiO ₂ particles were not used, and the viscosity of the antireflection layer forming ink was 135 cP at 25 ° C.

(Evaluation)
1. Measurement of viscosity of hard coat layer forming ink The viscosity of the hard coat layer forming ink was placed on a viscosity measuring device (Rheometer CVO120, manufactured by Bohlin) and kept at 25 ° C. The measurement conditions were a cone diameter of 20 mm, a cone inclination accuracy of 1 °, a gap of 30 microns, and a shear stress of 1 Pa.

2. Measurement of Hard Coat Layer Thickness The thickness of the hard coat layer was measured by photographing the cross section of the display filter using a scanning electron microscope.

3. Measurement of surface roughness Ra The surface roughness Ra of the laminate and the hard coat layer was measured using Surfcom 480A manufactured by Tokyo Seimitsu Co., Ltd. according to the method described in JISB0601.

  The surface roughness Ra is measured in the same direction as the mesh line direction between the meshes of the electromagnetic wave shielding layer 212 in the mesh shape, that is, the line AA ′ is directed from A to A ′ as shown in FIG. It was performed by measuring. FIG. 2 is a top view of the display filter on the side where the electromagnetic wave shielding layer 212 is formed. For convenience of explanation, only the mesh-like electromagnetic wave shielding layer 212 is shown.

4). Measurement of pencil hardness of hard coat layer The hardness was evaluated according to the pencil scratch test method of JIS K 5400.

5. Measurement of haze of display filter Three small pieces (50 × 50 mm) of the filter for display were cut out, the haze value was measured using a turbidimeter NDH Z000 manufactured by Nippon Denshoku Co., Ltd., and each average value was obtained. .

6). Evaluation of anti-glare property of display filter A fluorescent lamp (8000 cd / cm ² ) placed at a distance of 2 m and diagonally in front 30 with respect to the display filter is projected on the surface of the hard coat layer, and the reflected image is visually checked as follows. It was evaluated with.

A: The outline of the fluorescent lamp is hardly understood. B: The outline of the fluorescent lamp is blurred and slightly understood. X: The outline of the fluorescent lamp is clearly understood.

It is a schematic cross section of the filter for display of this invention. It is a model top view (only an electromagnetic wave shield layer is shown) of the filter for displays of the present invention.

Explanation of symbols

110 laminate,
111 transparent substrate,
112, 212 EMI shielding layer,
120 Antireflection layer.

Claims (19)

A laminate having a transparent substrate and a mesh-like electromagnetic wave shielding layer, and a hard coat layer formed on the surface of the laminated body having the electromagnetic wave shielding layer,
The display filter, wherein the hard coat layer has a surface roughness Ra of 0.02 to 0.20 μm.   2. The display filter according to claim 1, wherein the surface of the hard coat layer has a concavo-convex shape corresponding to a mesh-shaped concavo-convex shape formed by the electromagnetic wave shielding layer.   3. The display filter according to claim 1, wherein a surface roughness Ra of the surface on which the electromagnetic wave shielding layer of the laminate is formed is 0.1 to 7.0 μm. .   The display according to any one of claims 1 to 3, wherein the hard coat layer comprises a cured layer in which particles having an average particle diameter of 0.01 to 1 µm are dispersed in a curable resin. Filter.   The display filter according to claim 4, wherein the curable resin contains at least 15 mass% of hydroxyl group-containing (meth) acrylate with respect to the total amount of the curable resin.   The display filter according to claim 4, wherein the content of the particles in the hard coat layer is 10 to 900 parts by mass with respect to 100 parts by mass of the curable resin. Said _{particles, ITO, TiO 2, ZrO 2} , CeO 2, Al 2 O 3, Y 2 O 3, La 2 O 3, LaO least one metal oxide selected from ₂ the group consisting of Ho ₂ O ₃ It is a particle | grain, The filter for displays of any one of Claims 4-6 characterized by the above-mentioned.   The display filter according to claim 1, wherein the hard coat layer has a thickness of 3.0 to 10 μm.   The display filter according to any one of claims 1 to 8, wherein the haze is 7.0% or less.   The display filter according to claim 1, further comprising a low refractive index layer on the hard coat layer.   The display filter according to any one of claims 1 to 10, further comprising a near-infrared absorbing layer on a surface opposite to the surface on which the electromagnetic wave shielding layer of the laminate is formed.   The display filter according to claim 11, further comprising a transparent pressure-sensitive adhesive layer on the near-infrared absorbing layer.   A display filter according to claim 12, wherein the display filter is bonded to a glass plate.   13. A display comprising the display filter according to claim 12 bonded to a surface of an image display glass plate. A hard coat layer having a surface roughness Ra of 0.02 to 0.20 μm by applying a hard coat layer forming ink containing a curable resin on a laminate having a transparent substrate and a mesh-like electromagnetic wave shielding layer. Having a step of forming
The method for producing a display filter, wherein the viscosity of the hard coat layer forming ink is 10 to 5000 cP at 25 ° C.   16. The method for manufacturing a display filter according to claim 15, wherein the surface roughness Ra of the surface of the laminate on which the electromagnetic wave shielding layer is formed is 0.1 to 7.0 [mu] m.   The method for producing a display filter according to claim 15 or 16, wherein the curable resin contains at least 15 mass% of a hydroxyl group-containing (meth) acrylate with respect to the total amount of the curable resin.   The method for manufacturing a display filter according to any one of claims 15 to 17, wherein the hard coat layer forming ink further includes particles having an average particle diameter of 0.01 to 1 µm.   The method for producing a display filter according to claim 18, wherein the content of the particles is 10 to 900 parts by mass with respect to 100 parts by mass of the curable resin.

Images