JP2012093679A - Optical filter for display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical filter for display including s structure with a mesh-like conductive layer and a hard coat layer on the conductive layer which reduces generation of a large-sized convex defect on the hard coat layer.SOLUTION: An optical filter 20 for display includes a structure with a mesh-like conductive layer 13 on one surface of a transparent base material 12 and a hard coat layer 14 on the conductive layer 13. The hard coat layer 14 is composed of a composition for hard coat layer formation including a polymer whose weight average molecular weight is at least 6000.

Description

  The present invention is used for an image display part of a display such as a plasma display panel (PDP), a cathode ray tube (CRT) display, a liquid crystal display, an organic EL (electroluminescence) display, etc. The present invention relates to a method for manufacturing an optical filter.

  Conventionally, as a display filter that shields radiation of unnecessary electromagnetic waves generated from a display such as a plasma display panel (PDP), for a display having an electromagnetic shielding property and a light transmitting property in which a mesh-like conductive layer is provided in the filter. An optical filter is used.

  As the optical filter for display, for example, a conductive layer is provided on a single transparent substrate, and a functional layer such as a hard coat layer or an antireflection layer of the resin composition is laminated thereon. (Patent Document 1). The hard coat layer and the antireflection layer are the outermost surfaces on the viewer side, and flatness is important. In particular, when the planarity is lowered, the reflectance of the optical filter surface is increased due to optical distortion, and there is a problem that the internal visual information becomes difficult to see due to the influence of light from the outside. In particular, when the area of the convex defect projecting on the hard coat layer (referring to the horizontal projected area of the portion raised from the surface of the hard coat layer) is large, it becomes a lens-shaped defect, which causes a decrease in product yield.

FIG. 3 shows an example of an optical filter for display. In this optical filter, the hard coat layer 34 is formed on the mesh-like conductive layer 33 formed on the surface of the transparent substrate 32. The mesh-like conductive layer is obtained by, for example, printing conductive ink in a mesh shape and further performing metal plating such as copper or copper alloy. In general, when a hard coat layer or the like is applied onto a mesh-like conductive layer having irregularities, a coating liquid containing a resin composition is applied and cured by ultraviolet curing or the like. At this time, if a minute convex portion 40 due to metal plating unevenness or the like exists on the conductive layer, the resin composition is more extreme than the diameter S ¹ of the convex portion 40 around the convex portion 40 when the coating liquid is cured. large convex defect 42 of diameter S ² are formed, it may become lenticular drawback of large area above the.

JP 2007-243158 A

  Accordingly, an object of the present invention is an optical filter for display including a mesh-like conductive layer and a structure having a hard coat layer on the conductive layer, and the occurrence of convex defects having a large area in the hard coat layer is reduced. It is an object of the present invention to provide an optical filter for display and a method for manufacturing the same.

  The above object is an optical filter for display comprising a mesh-like conductive layer on one surface of a transparent substrate and a structure having a hard coat layer on the conductive layer, wherein the hard coat layer has a weight average molecular weight. It consists of a composition for forming a hard coat layer containing 6000 or more polymers.

  As a result, even if there are minute protrusions on the mesh-like conductive layer, the hard coat layer forming composition is easy to follow the shape of the protrusions when cured, so the bulge on the hard coat layer However, it can be prevented that the diameter becomes extremely larger than the diameter of the convex portion. Therefore, it can be set as the optical filter for displays by which generation | occurrence | production of the convex-shaped defect of a big area was reduced in the hard-coat layer. As this factor, for example, by using a polymer having a weight average molecular weight larger than usual as a resin component in the composition for forming a hard coat layer, the viscosity of the resin component before the formation of the hard coat layer becomes extremely high. This is probably because the positional change of the resin component after the layer formation is small.

Preferred embodiments of the optical filter for display according to the present invention are as follows.
(1) The polymer has a weight average molecular weight of 6,000 to 200,000. If the weight average molecular weight of a polymer is the said range, the hardness of a hard-coat layer can be made higher.
(2) The composition for forming a hard coat layer further contains a monomer having a polymerizable group. When a polymer having a large weight average molecular weight is used for the composition for forming a hard coat layer, the scratch resistance important as a function of the hard coat layer may be lowered. By using a monomer having a polymerizable group in combination, the occurrence of convex defects having a large area on the hard coat surface can be reduced, and the scratch resistance of the hard coat layer can be improved.
(3) The monomer is a monomer having three or more polymerizable groups in one molecule.
(4) The monomer has a molecular weight of 3000 or less. Thereby, the scratch resistance of the hard coat layer can be further improved. The monomer having a polymerizable group preferably has a molecular weight of 700 or less.
(5) The mass ratio of the polymer to the monomer (polymer / monomer) in the hard coat layer forming composition is 1/1 to 1/10. Thereby, it is possible to further reduce the occurrence of convex defects having a large area in the hard coat layer and improve the scratch resistance.
(6) The polymerizable group is a photopolymerizable group. For the formation of the hard coat layer, a photo-curing type is preferable because it can be cured in a short time and has excellent productivity.
(7) The polymerizable group is a group having an ethylenically unsaturated double bond.
(8) The group having an ethylenically unsaturated double bond is a (meth) acryloyl group.
(9) It has a minute convex part on the conductive layer. Having a convex portion on the conductive layer means having a convex portion that exceeds the height of the mesh on the mesh of the conductive layer or on the opening of the mesh. In the present invention, in particular, when such a minute convex portion exists, it is possible to prevent occurrence of a convex defect having a large area, which is effective.
(10) The conductive layer has a metal plating layer. Since a minute convex part may arise on the above conductive layers when forming a metal plating layer, the present invention is particularly effective.
(11) The difference (DH) between the layer thickness (D) of the hard coat layer from the transparent substrate surface and the height (H) of the mesh of the conductive layer from the transparent substrate surface, 1-5 μm. If the thickness of the hard coat layer is in the above range, even if there are minute convex portions on the conductive layer, the followability to the convex portions is high, so the occurrence of convex defects with a large area is further reduced. be able to.

  According to the optical filter for display of the present invention, even if there are minute convex portions on the mesh-like conductive layer, the bulge on the hard coat layer is prevented from becoming an extremely larger diameter than the diameter of the convex portions. Therefore, the occurrence of a convex defect having a large area in the hard coat layer can be reduced. Therefore, a high quality optical filter for display can be obtained with a high yield.

1 shows a typical example of an optical filter for display according to the present invention, and FIG. 1A is a schematic cross-sectional view of the optical filter for display. FIG. 1B is an enlarged view of a portion surrounded by a broken line in FIG. It is the schematic sectional drawing shown. It is a schematic plan view explaining the measuring method of the convex part fault distortion size which is 1 type of the evaluation method of the optical filter for displays of this invention (refer an Example). In order to demonstrate the subject of this invention, it is a schematic sectional drawing which shows an example of the optical filter for display of a prior art.

  Below, the optical filter for display of this invention and the manufacturing method of the optical filter for display are demonstrated, referring drawings. FIG. 1 shows a typical example of a display optical filter according to the present invention. FIG. 1 (a) is a schematic sectional view of the display optical filter, and FIG. 1 (b) is a broken line in FIG. 1 (a). It is the schematic sectional drawing which expanded and showed the enclosed part.

  In the present invention, the “weight average molecular weight” of an acrylic compound refers to a value measured in terms of polystyrene using a gel permeation chromatography (GPC) method.

  Moreover, in this invention, a hard-coat layer means what has the hardness more than H by the pencil hardness test prescribed | regulated by JISK5600 (1999).

  As shown in FIG. 1A, in the display optical filter 20, a mesh-like conductive layer 13 is formed over the entire surface of the rectangular transparent substrate 12. An intermediate layer may be formed between the transparent substrate 12 and the conductive layer 13 (not shown). A hard coat layer 14 is formed thereon, and a high refractive index layer 15 and a low refractive index layer 16 are further formed thereon as an antireflection layer. A near-infrared layer 17 and an adhesive layer 18 are formed on the other surface of the transparent substrate 12 on which the conductive layer 13 is formed, and the optical filter 20 is placed on the glass substrate 21 via the adhesive layer 18. Used by sticking to. Although the high refractive index layer 15 and the low refractive index layer 16 may be omitted as the antireflection layer, it is preferable that an antireflection layer is formed as an optical filter in order to suppress reflection of external light. The antireflection layer may be a layer combined with the high refractive index layer 15 and the low refractive index layer 16 as shown in FIG.

  In order to conduct electricity from the conductive layer 13 to the outside, the optical filter 20 has a functional layer such as a hard coat layer around the optical filter removed by laser irradiation or the like to expose the conductive layer, or conductive adhesive. It includes a structure in which a tape is sandwiched between conductive layers and grounded to the outside (not shown).

  In the present invention, the hard coat layer 14 is composed of a hard coat layer forming composition containing a polymer having a weight average molecular weight of 6000 or more.

In general, when a hard coat layer is formed on a transparent substrate on which a mesh-like conductive layer is formed, a composition for forming a hard coat layer mainly composed of a monomer or oligomer having a relatively low molecular weight polymerizable group is applied. And harden it by ultraviolet irradiation or the like. At this time, as in the example of the optical filter shown in FIG. 3, when the minute protrusion 40 is present on the conductive layer 33, the monomer or oligomer in the hard coat layer forming composition is polymerized and cured. In some cases, the surface of the hard coat layer 34 is distorted so as to be pulled by the convex portion 40, and a convex defect 42 having a diameter S ² that is extremely larger than the diameter S ¹ of the convex portion 40 may occur on the hard coat layer 34.

In the present invention, since the hard coat layer forming composition contains the polymer having the above weight average molecular weight, there are minute convex portions 50 on the conductive layer 13 as shown in FIG. Even when the hard coat layer is formed, the shape of the convex portion 50 can be easily followed when the hard coat layer is formed, and the diameter T ^{2 which is} not extremely large from the diameter T ¹ of the convex portion 50 on the hard coat layer 14. The convex portion 52 is only formed. As this factor, for example, it is considered as follows. That is, by using the above polymer in the hard coat layer forming composition, when the hard coat layer forming composition is applied and then dried and the solvent is removed, the viscosity of the resin component becomes extremely high, and the fluidity Will almost disappear. Then, since the positional change of the resin component before and after the hard coat layer is formed is small, it is considered that the shape of the convex portion 50 on the conductive layer 13 can be easily followed.

  If the convex portion on the hard coat layer has a large area, it becomes a lens-like convex defect, which causes a problem. However, if the convex portion is about 52 in the optical filter for display 20 in FIG. It doesn't matter. Therefore, the display filter of the present invention is a high-quality optical filter for display that can reduce the occurrence of convex defects having a large area in the hard coat layer and can be manufactured with a high yield.

  The polymer in the composition for forming a hard coat layer of the present invention may be any polymer as long as the weight average molecular weight is 6000 or more, and may or may not have a polymerizable group. If the weight average molecular weight is too large, the hardness of the hard coat layer may be lowered. Therefore, the weight average molecular weight is preferably 6000 to 200000, and more preferably 7000 to 80000. These polymers may be composed of one kind or two or more kinds of polymers.

For example, if the skeleton component is poly (meth) acrylate methyl, poly (meth) acrylate butyl, poly (acrylonitrile / styrene), poly ((meth) acrylate 2-hydroxymethyl / (meth) acrylate), poly ( (Meth) acrylic acid 2-hydroxymethyl / (meth) acrylic acid butyl), and copolymers of these resins and silicone resins,
Polyol compounds (for example, ethylene glycol, propylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butyl-1, Polyols such as 3-propanediol, trimethylolpropane, diethylene glycol, dipropylene glycol, polypropylene glycol, 1,4-dimethylolcyclohexane, bisphenol A polyethoxydiol, polytetramethylene glycol, the polyols and succinic acid, maleic acid Polyester polyols which are reaction products of polybasic acids such as itaconic acid, adipic acid, hydrogenated dimer acid, phthalic acid, isophthalic acid, terephthalic acid, etc., or their acid anhydrides, and the above-mentioned polyols and ε-capro Polycaprolactone polyols which are reaction products with kuton, reaction products of the above-mentioned polyols with the above polybasic acids or ε-caprolactone of these acid anhydrides, polycarbonate polyols, polymer polyols, etc.) and organic polyisocyanates (for example, , Tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane-4,4′-diisocyanate, dicyclopentanyl diisocyanate, hexamethylene diisocyanate, 2,4,4′-trimethylhexamethylene diisocyanate, 2,2′-4- Trimethylhexamethylene diisocyanate) and hydroxyl group-containing (meth) acrylates (for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxy Loxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, cyclohexane-1,4-dimethylol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol penta (meth) acrylate, And polyurethane (meth) acrylate, which is a reaction product of dipentaerythritol hexa (meth) acrylate, glycerin di (meth) acrylate, and the like.

  These compounds can be used alone or in combination.

  Commercially available products include Beamset 371 (Arakawa Chemical Industries), Macromonomer AA-6, AA-10, AS-6, AB-6, AA-10, AN-6S (above, manufactured by Toagosei Co., Ltd.), HCX-201-54 (manufactured by Adeka), Foret M-80 (manufactured by Soken Chemical Co., Ltd.) and the like can be mentioned.

  In addition, when a polymer having a large weight average molecular weight is used for the hard coat layer forming composition, the hard coat layer may have reduced scratch resistance as a function of the hard coat layer. It is preferable to include a monomer having a polymerizable group. From the viewpoint of reactivity, a monomer having three or more polymerizable groups in one molecule is preferable. Moreover, the molecular weight of the monomer having the polymerizable group is preferably 3000 or less, more preferably 700 or less, and particularly preferably 200 to 600. The molecular weight of the monomer may be a weight average molecular weight or a formula weight obtained from a chemical formula. In this case, the monomer may be an oligomer. By using the monomer in combination, it is possible to reduce the occurrence of convex defects having a large area in the hard coat layer and improve the scratch resistance of the hard coat layer.

  In addition, the mixing ratio of the polymer and the monomer in the composition for forming a hard coat layer is not particularly limited. However, both the occurrence of convex defects having a large area in the hard coat layer and the improvement of scratch resistance are compatible. In order to achieve this, the mass ratio of the polymer to the monomer (polymer / monomer) is preferably 1/1 to 1/10, and more preferably 1/3 to 1/7.

  In the present invention, the polymerizable group of the monomer may be either a thermally polymerizable group or a photopolymerizable group. The polymerizable group is preferably a photopolymerizable group in that it can be cured in a short time by ultraviolet irradiation and is excellent in productivity.

  The polymerizable group may be any group such as a group having an ethylenically unsaturated double bond or a cyclic ether group such as an epoxy group or an oxetane group. However, in terms of reactivity, an ethylenically unsaturated double bond may be used. And a (meth) acryloyl group is particularly preferable.

  Any monomer (or oligomer) having a polymerizable group (preferably 3 or more per molecule) may be used. The monomer (or oligomer) having a (meth) acryloyl group may be a monomer or an oligomer composed of the same components as those exemplified in the above polymer, such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate. 4-hydroxybutyl (meth) acrylate, 2-ethylhexyl polyethoxy (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, phenyloxyethyl (meth) acrylate, tricyclodecane mono (meth) acrylate, di Cyclopentenyloxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, acryloylmorpholine, N-vinylcaprolactam, 2-hydroxy-3-phenyloxypropyl (meth) acrylate , O-phenylphenyloxyethyl (meth) acrylate, neopentyl glycol di (meth) acrylate, neopentyl glycol dipropoxy di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, tricyclodecandi Methylol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, nonanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) Acrylate, pentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tris [(meth) acryloxyethyl] isocyanurate, dito (Meth) acrylate monomers such as methylolpropane tetra (meth) acrylate, bisphenol type epoxy resin such as bisphenol A type epoxy resin, bisphenol F type epoxy resin and bisphenol type epoxy (meth) which is a reaction product of (meth) acrylic acid Examples include (meth) acrylate oligomers such as acrylate. These compounds can be used alone or in combination. In particular, it is preferable to mainly use hard polyfunctional monomers such as pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate.

  Furthermore, it is preferable to mix | blend a photoinitiator with the composition for hard-coat layer formation. As the photopolymerization initiator, any compound suitable for the properties of the resin component to be used 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 photopolymerization initiators may be optionally selected from one or more known photopolymerization accelerators such as benzoic acid type or tertiary amine type such as 4-dimethylaminobenzoic acid. It can be used by mixing at a ratio. Moreover, it can be used by 1 type, or 2 or more types of mixture of only a photoinitiator. In particular, 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals, Irgacure 184) is preferable.

  Generally the quantity of a photoinitiator is 0.1-10 mass% with respect to a resin composition, Preferably it is 0.1-5 mass%.

  Furthermore, the composition for forming a hard coat layer may contain a small amount of an ultraviolet absorber, an infrared absorber, an anti-aging agent, a paint processing aid, a colorant and the like. In particular, it is preferable to contain an ultraviolet absorber (for example, a benzotriazole-based ultraviolet absorber or a benzophenone-based ultraviolet absorber), whereby yellowing of the filter can be efficiently prevented. The amount thereof is generally 0.1 to 10% by mass, preferably 0.1 to 5% by mass, based on the resin composition.

  In order to form the hard coat layer, for example, the hard coat layer forming composition containing the resin component, the photopolymerization initiator, and the additive as necessary is added with a solvent such as toluene, n-hexane, or methyl ethyl ketone. An example is a method in which a coating solution in solution is coated with a gravure coater or the like, then dried, and then cured with ultraviolet rays. This wet coating method has the advantage that the film can be uniformly formed at high speed at low cost. After this coating, for example, by irradiating with ultraviolet rays and curing, effects of improving adhesion and increasing the hardness of the film can be obtained.

  In the case of ultraviolet curing, many light sources that emit light in the ultraviolet to visible range can be used as the light source, such as ultra-high pressure, high pressure, low pressure mercury lamp, chemical lamp, xenon lamp, halogen lamp, mercury lamp, carbon arc lamp, incandescent lamp. And laser light. 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. Moreover, in order to accelerate curing, the laminate may be preheated to 40 to 120 ° C. and irradiated with ultraviolet rays.

  The layer thickness of the hard coat layer is usually 1 to 50 μm, preferably 5 to 20 μm from the surface of the transparent substrate. In the present invention, in the case where the minute protrusions 50 are present on the conductive layer 13, in order to increase the followability of the hard coat layer to the protrusions 50, the layer of the hard coat layer 13 from the surface of the transparent substrate 12 is used. The difference (D−H) between the thickness (D) and the height (H) of the mesh of the conductive layer 13 from the surface of the transparent substrate 12 is preferably 1 to 5 μm (see FIG. 1B). .

  This is because as the thickness of the layer decreases, the followability to the convex portion increases as described in the examples described later. Thereby, generation | occurrence | production of the convex-shaped defect of the big area of the hard-coat layer 13 can further be reduced.

  Any material and process may be used for the optical filter for display of the present invention as long as the object of the present invention can be achieved. A preferred embodiment will be described below.

[Transparent substrate]
The transparent substrate is generally a transparent plastic film. The material is not particularly limited as long as it is transparent (meaning “transparent to visible light”). Examples of plastic films include polyester [eg, polyethylene terephthalate (PET), polybutylene terephthalate], polymethyl methacrylate (PMMA), acrylic resin, polycarbonate (PC), polystyrene, triacetate resin, polyvinyl alcohol, polyvinyl chloride, poly Examples thereof include vinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane and the like. Among these, polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), etc. are highly resistant to loads during processing (heat, solvent, bending, etc.) and particularly highly transparent. preferable. In particular, PET is preferable because it has excellent processability. In addition, organic dyes contained in the near-infrared absorbing layer and the like are likely to be deteriorated in durability by receiving ultraviolet rays, but polyesters such as PET are preferable because they tend to absorb such ultraviolet rays. You may provide the easily bonding layer for improving the adhesiveness of each functional layer on the surface of a transparent base material. The easy-adhesion layer is, for example, a thermosetting resin such as a copolyester resin and a polyurethane resin, or a metal oxide fine particle such as SiO ₂ , ZrO ₂ , TiO ₂ , or Al ₂ O ₃ , preferably an average. What adjusted the refractive index by mix | blending metal oxide fine particles with a particle size of 1-100 nm is used.

  The thickness of the transparent substrate varies depending on the use of the optical filter and the like, but generally 1 μm to 10 mm, 1 μm to 5 mm, particularly 25 to 250 μm is preferable.

[Conductive layer]
The mesh-like conductive layer is generally set to be 10Ω / □ or less, preferably in the range of 0.001 to 5Ω / □, particularly 0.005 to 5Ω / □. As the mesh-like conductive layer, metal fibers and metal-coated organic fiber metals made into a mesh, copper foil on a transparent film etched into a mesh and provided with openings, conductive on the transparent film And the like, in which a conductive ink is printed in a mesh shape.

  In the case of a mesh-shaped conductive layer, the mesh preferably has a wire diameter of 1 μm to 1 mm and an aperture ratio of 40 to 95% made of metal fibers and / or metal-coated organic fibers. A more preferable wire diameter is 10 to 500 μm, and an aperture ratio is 50 to 95%. When the wire diameter exceeds 1 mm in the mesh-like conductive layer, the electromagnetic wave shielding property is improved, but the aperture ratio is lowered and cannot be made compatible. If it 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. When the aperture ratio is less than 40%, the light transmittance is reduced, and the light amount from the display is also reduced.

  In addition, the aperture ratio of a mesh means the area ratio which the opening part occupies in the projection area of the said mesh.

  1-15 micrometers is preferable and, as for the height from the transparent base material surface of the mesh of a conductive layer, 3-10 micrometers is more preferable.

  As the metal of the mesh-like conductive layer and the metal of the metal-coated organic fiber, copper, stainless steel, aluminum, nickel, titanium, tungsten, tin, lead, iron, silver, carbon or alloys thereof, 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.

  When a conductive foil such as a metal foil is subjected to pattern etching, copper, stainless steel, aluminum, nickel, iron, brass, or an alloy thereof, preferably copper, stainless steel, or aluminum is used as the metal of the metal foil.

  If the thickness of the metal foil is too thin, it is not preferable in terms of handleability and workability of pattern etching, and if it is too thick, it affects the thickness of the film obtained, and the time required for the etching process becomes long. The thickness is preferably about 1 to 200 μm.

  The shape of the etching pattern is not particularly limited, and examples thereof include a grid-like metal foil in which square holes are formed, and a punching metal-like metal foil in which circular, hexagonal, triangular or elliptical holes are formed. It is done. Further, the holes are not limited to those regularly arranged, and may be a random pattern. The area ratio of the opening portion on the projection surface of the metal foil is preferably 20 to 95%, more preferably 40 to 95%, and particularly preferably 60 to 95%.

  In addition to the above, as a mesh-like conductive layer, dots are formed on the film surface by 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, A mesh-like conductive layer obtained by bringing the film surface into contact with a solvent to remove the dots and the conductive material layer on the dots may be used.

  A metal plating layer may be further provided on the conductive layer in order to improve conductivity. The metal plating layer can be formed by a known electrolytic plating method or electroless plating method. As the metal used for plating, it is generally possible to use copper, copper alloy, nickel, aluminum, silver, gold, zinc, tin or the like, preferably copper, copper alloy, silver, or nickel, In particular, it is preferable to use copper or a copper alloy from the viewpoint of economy and conductivity.

  Moreover, you may give anti-glare performance. When this anti-glare treatment is performed, a blackening treatment may be performed on the surface of the (mesh) conductive layer. For example, oxidation treatment of a metal film, black plating such as chromium alloy, application of black or dark ink, and the like can be performed.

  As described above, the present invention is effective when the conductive layer has a minute convex portion. In particular, when the conductive layer has a metal plating layer, such a minute convex portion may be generated due to uneven plating in the plating step for forming the metal plating layer, which is effective.

[Antireflection layer]
Among the antireflection layers, the high refractive index layer is doped with ITO, ATO, Sb ₂ O ₃ , SbO ₂ , In ₂ O ₃ , SnO ₂ , ZnO, and Al in the resin component (preferably UV curable resin). It is preferable to use a layer (cured layer) in which conductive metal oxide fine particles (inorganic compounds) such as ZnO and TiO ₂ are dispersed. The metal oxide fine particles preferably have an average particle size of 10 to 10,000 nm, preferably 10 to 50 nm. In particular, ITO (especially having an average particle diameter of 10 to 50 nm) is preferable. The film thickness is generally in the range of 10 to 500 nm, preferably 20 to 200 nm.

  Of the antireflection layer, the low refractive index layer is composed of fine particles such as silica and fluororesin, preferably 10 to 40% by weight (preferably 10 to 30% by weight) of hollow silica resin component (preferably UV curable resin). A layer (cured layer) dispersed therein is preferable. The film thickness is generally in the range of 10 to 500 nm, preferably 20 to 200 nm. As the hollow silica, those having 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 are preferable.

  As the resin component used for these antireflection layers, the same resin components as those for ordinary hard coat layers can be used. Generally, it is a thermosetting resin such as phenol resin, resorcinol resin, urea resin, melamine resin, epoxy resin, acrylic resin, urethane resin, furan resin, silicone resin, or ultraviolet curable resin. An ultraviolet curable resin is preferable from the viewpoint of excellent productivity. When an ultraviolet curable resin is used, it is used as an ultraviolet curable resin composition (consisting of an ultraviolet curable resin, a photopolymerization initiator, etc.). As the ultraviolet curable resin, the above-mentioned polymers, monomers and the like can be used.

  The visible light transmittance as a whole is preferably 85% or more together with the hard coat layer described above. Both the visible light transmittance of the high refractive index layer and the low refractive index layer are preferably 85% or more.

  When the hard coat layer and the above two layers are used, for example, the hard coat layer has a total thickness of 1 to 20 μm, the high refractive index layer has a thickness of 50 to 150 nm, and the low refractive index layer has a thickness of 50 to 50 μm. It is preferable that it is 150 nm.

  The antireflection layer can be formed in the same manner as the hard coat layer described above. In this case, each layer of the hard coat layer and the antireflection layer may be applied and cured one by one, or all the layers may be applied and then cured together. In the case of continuous processing, the coating surface may be scratched unless it is cured after application of each layer. Therefore, it is preferable to coat and cure each layer one by one.

[Near-infrared absorbing layer]
The near-infrared absorbing layer formed on the other surface of the transparent substrate on which the conductive layer is formed is generally obtained by forming a layer containing a pigment or the like on the surface of the substrate film. The near-infrared absorbing layer can be obtained, for example, by applying a coating liquid containing the above-described pigment and binder resin, and if necessary, drying and curing. Alternatively, it can also be obtained by applying a coating solution containing the above-mentioned pigment and binder resin and simply drying it. 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 include azomethine dyes, azo dyes, polyazo dyes, diimonium dyes, aminium dyes, and anthraquinone dyes, and cyanine dyes, phthalocyanine dyes, and diimonium dyes are particularly preferable. These dyes can be used alone or in combination. Examples of the binder resin include thermoplastic resins such as acrylic resins.

  The near-infrared absorbing layer may be provided with a function of adjusting color tone by providing a neon emission absorbing function (neon cut function). For this purpose, a neon-emission absorption layer (neon cut 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 near-infrared absorption characteristics, it is preferable that the transmittance of 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 layer thickness of the near infrared absorbing layer is generally 0.5 to 50 μm.

[Adhesive layer]
As the transparent pressure-sensitive adhesive layer, any resin can be used as long as it has an adhesion function of adhering to the glass substrate. For example, an acrylic adhesive formed from an ethylene-vinyl acetate copolymer (EVA), an ethylene-methyl acrylate copolymer, butyl acrylate, a rubber adhesive, SEBS (styrene / ethylene / butylene / styrene) and TPE-based pressure-sensitive adhesives and adhesives mainly composed of a thermoplastic elastomer (TPE) such as SBS (styrene / butadiene / styrene) can also be used.

  The layer thickness is generally in the range of 5 to 500 μm, particularly 10 to 100 μm. The optical filter is generally equipped by pressing the pressure-sensitive adhesive layer on the glass plate of the display.

  Hereinafter, the present invention will be described with reference to examples.

1. Convex defect model test of hard coat layer (Example 1)
(1) Preparation of hard coat layer forming composition (coating liquid) Resin component (HCX-201-54 (manufactured by Adeka), weight average molecular weight of about 7000 (GPC method (polystyrene conversion))) solid content 30% by mass ( A solvent (adjusted with methyl ethyl ketone, isopropyl alcohol, cyclohexanone)) and a photopolymerization initiator (Irgacure 184 (manufactured by Ciba Specialty Chemicals)) with a resin component solid content of 2.0% by mass are stirred and mixed to form a coating solution. Was prepared.
(2) Convex defect model preparation of hard coat layer 0.05% by mass of glass beads (diameter: 50 μm (Micropearl SP-250 (manufactured by Sekisui Chemical Co., Ltd.)) is dispersed in the coating solution prepared in (1). The film was finally coated on a PET film so as to form a 5 μm hard coat layer, which was dried at 70 ° C. for 30 seconds and then cured with a high-pressure mercury lamp at a UV irradiation amount of 300 mJ / cm ² . A hard coat layer was formed.
(3) Measurement of strain size The obtained hard coat layer sample was observed with an optical microscope, and as shown in FIG. 2, the strain size of the convex defect model of the hard coat layer formed on the glass beads was measured.

(Example 2)
A hard coat layer was formed in the same manner as in Example 1 except that the resin component was changed to Foret M-80 (manufactured by Soken Chemical Co., Ltd.) (weight average molecular weight of about 80,000 (GPC method (polystyrene conversion)), and strain size was measured. .

(Example 3)
The resin component was changed to Foret M-80 (manufactured by Soken Chemical Co., Ltd.) with a solid content of 7.5% by mass and dipentaerythritol hexaacrylate ADPH (manufactured by Shin-Nakamura Chemical Co., Ltd.) (molecular weight 578) with a solid content of 22.5% by mass. In the same manner as in Example 1, a hard coat layer was formed, and the strain size was measured.

Example 4
Except for changing the resin component to 5% by mass (solid content) foret M-80 (manufactured by Soken Chemical Co., Ltd.) and 25% by mass (solid content) of dipentaerythritol hexaacrylate ADPH (manufactured by Shin-Nakamura Chemical Co., Ltd.) A hard coat layer was formed in the same manner as in No. 1, and the strain size was measured.

(Example 5)
Other than changing the resin component to Foret M-80 (manufactured by Soken Chemical Co., Ltd.) 3.75% by mass (solid content) and dipentaerythritol hexaacrylate ADPH (manufactured by Shin-Nakamura Chemical Co., Ltd.) 26.25% by mass (solid content) In the same manner as in Example 1, a hard coat layer was formed, and the strain size was measured.

(Example 6)
Resin component is foret M-80 (manufactured by Soken Chemical Co., Ltd.) 7.5% by mass (solid content), and urethane accelerator UA-53H (manufactured by Shin-Nakamura Chemical Co., Ltd.) (molecular weight 2300) 22.5% by mass (solid content) A hard coat layer was formed in the same manner as in Example 1 except that the strain size was changed, and the strain size was measured.

(Example 7)
Example 1 except that the resin component was changed to 5% by mass (solid content) of Foret M-80 (manufactured by Soken Chemical) and 25% by mass (solid content) of urethane acrylate UA-53H (manufactured by Shin-Nakamura Chemical Co., Ltd.) A hard coat layer was formed in the same manner as above, and the strain size was measured.

(Example 8)
Except for changing the resin component to Foret M-80 (manufactured by Soken Chemical Co., Ltd.) 3.75% by mass (solid content) and urethane acrylate UA-53H (manufactured by Shin-Nakamura Chemical Co., Ltd.) 26.25% by mass (solid content) A hard coat layer was formed in the same manner as in Example 1, and the strain size was measured.

(Comparative Example 1)
A hard coat layer was formed in the same manner as in Example 1 except that the resin component was changed to dipentaerythritol hexaacrylate ADPH (manufactured by Shin-Nakamura Chemical Co., Ltd.), and the strain size was measured. The results are shown in Table 1.

2. Scratch resistance evaluation In order to evaluate a preferred embodiment, the hard coat layers obtained in Examples 1 to 8 and Comparative Example 1 were evaluated by scratching 10 times with steel wool # 0000 at a load of 400 g. In the evaluation, a case where there was no flaw was marked with ◯, a case where there was a slight flaw, Δ, and a case where there was a clear flaw, x. The results are shown in Table 1.

3. Variation of strain size due to difference in layer thickness of hard coat layer (Example 9)
A hard coat layer was formed in the same manner except that the thickness of the hard coat layer of Example 1 was changed to 3 to 10 μm, and the strain size was measured. The results are shown in Table 2.

(Example 10)
A hard coat layer was similarly formed except that the thickness of the hard coat layer of Example 2 was changed to 3 to 10 μm, and the strain size was measured. The results are shown in Table 2.

(Comparative Example 2)
A hard coat layer was formed in the same manner except that the thickness of the hard coat layer of Comparative Example 1 was changed to 3 to 10 μm, and the strain size was measured. The results are shown in Table 2.

  As shown in Table 1, in the hard coat layer using the hard coat layer forming composition containing the polymer having a weight average molecular weight of 6000 or more in Examples 1 to 8, the hard coat of Comparative Example 1 using a resin component having a low molecular weight. Compared with the layer, the strain size of the convex defect model formed on the glass beads is small, suggesting that even if there is a small convex part under the hard coat layer, the occurrence of convex defects with a large area can be reduced. It was done.

  In addition, the evaluation of Examples 3 to 8 showed that when the polymer and a monomer having a polymerizable group were used in combination, it was possible to achieve both a reduction in the occurrence of convex defects and an improvement in scratch resistance.

  Furthermore, as shown in Table 2, it was suggested that the smaller the hard coat layer thickness, the smaller the strain size of the convex defect model, and the occurrence of convex defects having a larger area can be reduced.

  In addition, this invention is not limited to the structure and Example of said embodiment, A various deformation | transformation is possible within the range of the summary of invention.

  According to the present invention, a high-quality optical filter for display provided with a conductive layer effective for PDP or the like can be provided at low cost.

12, 32 Transparent base material 13, 33 Conductive layers 14, 34 Hard coat layer 15 High refractive index layer 16 Low refractive index layer 17 Near-infrared absorbing layer 18 Adhesive layer 20 Optical filter 21 Glass substrates 40, 50, 52 Convex part 42 Convex defect

Claims (12)

An optical filter for display comprising a structure having a mesh-like conductive layer on one surface of a transparent substrate and a hard coat layer on the conductive layer,
The optical filter for a display, wherein the hard coat layer is made of a composition for forming a hard coat layer containing a polymer having a weight average molecular weight of 6000 or more.   The optical filter for display according to claim 1, wherein the polymer has a weight average molecular weight of 6,000 to 200,000.   The optical filter for a display according to claim 1 or 2, wherein the composition for forming a hard coat layer further contains a monomer having a polymerizable group.   The optical filter for display according to claim 3, wherein the monomer is a monomer having three or more polymerizable groups in one molecule.   The optical filter for display according to claim 3 or 4, wherein the monomer has a molecular weight of 3000 or less.   The optical filter for a display according to any one of claims 3 to 5, wherein a mass ratio of the polymer to the monomer (polymer / monomer) in the hard coat layer forming composition is 1/1 to 1/10. .   The optical filter for display according to any one of claims 3 to 6, wherein the polymerizable group is a photopolymerizable group.   The optical filter for display according to any one of claims 3 to 7, wherein the polymerizable group is a group having an ethylenically unsaturated double bond.   The optical filter for display according to claim 8, wherein the group having an ethylenically unsaturated double bond is a (meth) acryloyl group.   The optical filter for display according to any one of claims 1 to 9, wherein the conductive layer has a minute convex portion.   The optical filter for display according to claim 1, wherein the conductive layer has a metal plating layer.   The difference (D−H) between the layer thickness (D) of the hard coat layer from the surface of the transparent substrate and the height (H) of the mesh of the conductive layer from the surface of the transparent substrate is 1 to 5 μm. The optical filter for display according to any one of claims 1 to 11.

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