JP2006030870A - Polarizing plate and liquid crystal display device - Google Patents

Abstract

Disclosed is a polarizing plate and a liquid crystal display device that are excellent in transparency, mechanical strength, antireflection performance, scratch resistance, and adhesion by making a transparent protective layer of a polarizer specific. is there.
An alicyclic structure-containing polymer resin film having an in-plane die line formed in the longitudinal direction on one side of a deflector is extremely fine, and a hard coat layer and an antireflection layer are laminated to form a resin film. An alicyclic structure-containing polymer resin film having a retardation and laminated on the other surface of the deflector is laminated as a protective film for the deflector.
[Selection figure] None

Description

  The present invention relates to a polarizing plate and a liquid crystal display device. More specifically, the present invention relates to a polarizing plate and a liquid crystal display device that are excellent in transparency, mechanical strength, antireflection performance, scratch resistance, and adhesion.

  A liquid crystal display device (hereinafter referred to as “LCD”) is characterized by being thin, lightweight, and having low power consumption. The field of use of LCDs is expanding from conventional calculators and watches to automobile applications that require durability and heat resistance, such as car navigation systems and automobile inner panels.

  LCDs are generally composed of a liquid crystal cell that has the function of switching the passage and blocking of polarized light by controlling the orientation direction of liquid crystal molecules by applying an electric field, and a polarizing plate with the transmission axis arranged at right angles across the cell. Is done.

  As a polarizing plate, what laminated | stacked the polarizing plate protective film on both polarizers is used. The protective film is a film that is attached to the outside of the polarizer for scratch resistance, antireflection properties, and the like of the liquid crystal display element.

  As the protective film, a cellulose ester film, particularly triacetyl cellulose (hereinafter referred to as “TAC”) has been used because of its excellent optical properties.

  However, since TAC is highly hygroscopic, it expands and contracts due to humidity and easily causes unevenness due to stress strain. Therefore, distortion due to moisture absorption generates internal stress and causes unevenness. However, as LCDs become thinner, larger, and brighter, the durability of polarizing plates has been demanded more than ever, and the TAC protective layer has sufficient moisture resistance to satisfy it. There was a problem of not having.

  A polarizing plate protective film for protecting a polarizer made of highly stretched polyvinyl alcohol has 1) a small phase difference expressed by the product of birefringence and thickness, and 2) the level of the film due to external stress. It is required that the phase difference hardly changes, 3) the unevenness of the phase difference in the plane direction and the thickness direction is small, and 4) the phenomenon of image distortion due to the so-called lens effect caused by the unevenness of the film surface is required.

  In other words, if the phase difference is large, the phase difference changes due to external stress, etc., the in-plane retardation is large, or there is a lens effect due to irregularities on the film surface, the image quality of the liquid crystal display device is significantly reduced. Let In other words, color jumping phenomenon such as partial color fading, and adverse effects such as image distortion occur.

Therefore, recently, it has been proposed to use a thermoplastic saturated norbornene resin sheet having excellent moisture resistance instead of TAC as a protective layer of a polarizer (Patent Documents 1 and 2). However, those using only a norbornene-based resin film as a protective layer for the polarizer have insufficient points in terms of scratch resistance, antireflection, and adhesion, and there are frame failures, color irregularities, bright spot defects, etc. It sometimes occurred.
JP 2001-272534 A JP 2003-207637 A

 An object of the present invention is to provide a polarizing plate and a liquid crystal display device which are excellent in all of transparency, mechanical strength, heat resistance, antireflection performance, scratch resistance and adhesion.

  As a result of intensive studies to solve the above problems, the present inventors have used a specific protective film for a polarizing plate, and sequentially laminated a hard coat layer and an antireflection layer on one side of the protective film to provide a liquid crystal display device The present inventors have found that an optimal polarizing plate can be obtained, and have completed the present invention based on this finding.

Thus, according to the present invention,
(1) One surface of a polarizer is made of an alicyclic structure-containing polymer resin, has an average thickness of 5 to 200 μm, a moisture permeability of 0.3 to 40 g / m ² · 24 hr, and an in-plane maximum value. Is a resin film (A) having a maximum die line depth of 50 nm or less and a minimum die line width of 500 nm or more, a hard coat layer (B) and an antireflection layer (C), which are sequentially laminated,
Polarized light formed by laminating a resin film (D) having an average thickness of 5 to 200 μm and a moisture permeability of 0.3 to 40 g / m ² · 24 hr, on the other surface, made of an alicyclic structure-containing polymer resin. Board.

(2) The polarizing plate of (1), wherein the antireflective layer (C) has a refractive index of 1.36 or less.

(3) The polarizing plate according to any one of (1) and (2), wherein the antireflection layer (C) is a layer made of airgel.

(4) The polarizing plate according to any one of (1) to (4), wherein the resin film (D) is a film showing retardation.

  (5) A liquid crystal display device in which the polarizing plate of any one of (1) to (4) is installed with the antireflection layer (C) side facing the viewing side.

  The polarizing plate of the present invention has no distortion of the polarizer due to heat or moisture absorption, has a low reflectance, is excellent in scratch resistance and visibility, and is excellent in contrast in bright and dark display, and thus can be suitably used for a liquid crystal display device. .

The polarizing plate of the present invention comprises an alicyclic structure-containing polymer resin on one surface of a polarizer, has a thickness of 5 to 200 μm, a moisture permeability of 0.3 to 40 g / m ² · 24 hr, and an in-plane A resin film (A) having a maximum value of 4 nm or less, a maximum die line depth of 50 nm or less, and a minimum die line width of 500 nm or more, a hard coat layer (B), and an antireflection layer (C) are sequentially laminated,
A resin film (D) having a thickness of 5 to 200 μm and a moisture permeability of 0.3 to 40 g / m ² · 24 h is laminated on the other surface.

    The polarizer used in the present invention is not particularly limited as long as it has a function as a polarizer. For example, (1) vinyl alcohol polymer (PVA) / iodine polarizer, (2) PVA / dye polarizer with dichroic dye adsorbed and oriented on PVA film, (3) dehydrated from PVA film A polyene polarizer in which a polyene is formed by inducing a reaction or by dehydrochlorination reaction of a polyvinyl chloride film, (4) The surface and / or the inside of a PVA film comprising a modified PVA containing a cationic group in the molecule And a polarizer having a dichroic dye. From the viewpoint of the initial polarization performance of the polarizer, (1) a PVA / iodine polarizer is preferable, and from the viewpoint of heat resistance, (2) a PVA / dye polarizer is preferable.

  A polarizer is not specifically limited by the manufacturing method. For example, 1) a method for adsorbing iodine ions after stretching a PVA-based film, 2) a method for stretching after dyeing a PVA-based film with a dichroic dye, and 3) after stretching a PVA-based film with a dichroic dye There are known methods such as a dyeing method, 4) a method of stretching a dichroic dye after printing on a PVA film, and 5) a method of printing a dichroic dye after stretching the PVA film.

    For example, in the method of 1), more specifically, iodine is dissolved in a potassium iodide solution to form iodine ions, the ions are adsorbed on a PVA film and stretched, and then bathed in a 1 to 4% boric acid aqueous solution. A polarizing plate is produced by dipping at a temperature of 30 to 40 ° C. More specifically, in the method of 2), the PVA film is dipped in a boric acid aqueous solution in the same manner as in 1), and then stretched about 3 to 7 times in a uniaxial direction to form a 0.05 to 5% dichroic dye aqueous solution. Is immersed in the bath at a temperature of 30 to 40 ° C. to adsorb the dye, dried at 80 to 100 ° C. and heat-fixed to produce a polarizer. The polarization degree of the polarizer is preferably 99.993% or more.

  The resin film (A) used in the present invention is made of an alicyclic structure-containing polymer resin. The alicyclic structure-containing polymer resin has an alicyclic structure in the main chain and / or side chain, and preferably contains an alicyclic structure in the main chain from the viewpoint of mechanical strength, heat resistance and the like. .

  Examples of the alicyclic structure of the polymer include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene) structure. From the viewpoint of mechanical strength and heat resistance, cycloalkane. A structure or a cycloalkene structure is preferable, and a cycloalkane structure is most preferable.

  The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 in the mechanical strength, The properties of heat resistance and film formability are highly balanced and suitable. The proportion of the repeating unit containing the alicyclic structure in the alicyclic structure-containing polymer used in the present invention may be appropriately selected according to the purpose of use, but is preferably 30% by weight or more, Preferably it is 50% by weight or more, particularly preferably 70% by weight or more, and most preferably 90% by weight or more. It is preferable from the viewpoints of transparency and heat resistance of the film that the ratio of the repeating unit having an alicyclic structure in the polymer resin having an alicyclic structure is in this range.

  Specifically, the polymer resin having an alicyclic structure includes (1) a norbornene polymer, (2) a monocyclic olefin polymer, (3) a cyclic conjugated diene polymer, and (4) vinyl. Examples thereof include alicyclic hydrocarbon polymers and hydrogenated products thereof. Among these, norbornene-based polymers are more preferable from the viewpoints of transparency and moldability.

  Specific examples of the norbornene-based polymer include ring-opening polymers of norbornene-based monomers, ring-opening copolymers of norbornene-based monomers and other monomers capable of ring-opening copolymerization, and hydrogenated products thereof, norbornene-based polymers Examples include addition polymers of monomers and addition copolymers with other monomers copolymerizable with norbornene monomers. Among these, from the viewpoint of transparency, a ring-opening (co) polymer hydrogenated product of a norbornene-based monomer is most preferable.

  The polymer resin having the alicyclic structure is selected from known polymers disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-321302.

Among norbornene polymers suitably used for the resin film of the present invention, X: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure and Y: tricyclo [4.3 are used as repeating units. .0.1 ^2,5 ] decane-7,9-diyl-ethylene structure, and the content of these repeating units is 90% by weight or more based on the total repeating units of the thermoplastic norbornene resin. And the ratio of the content ratio of X and the content ratio of Y is preferably 100: 0 to 40:60 in terms of a weight ratio of X: Y. By using such a resin, it is possible to obtain a resin film having no dimensional change over a long period of time and excellent optical property stability.

Examples of the monomer that gives a repeating unit having the structure of X by polymerization include norbornene-based monomers having a structure in which a 5-membered ring is bonded to a norbornene ring. More specifically, tricyclo [4.3.0. 1 ^2,5 ] deca-3,7-diene (common name: dicyclopentadiene) and derivatives thereof, 7,8-benzotricyclo [4.3.0.1 ^0,5 ] dec-3-ene (conventional) Name: methanotetrahydrofluorene), and derivatives thereof.

As the monomer polymerized to provide the repeating units of the structure Y, tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10 ] deca-3,7-diene (common name: tetracyclododecene) and its derivatives.

  Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. In addition, these substituents may be the same or different and a plurality may be bonded to the ring. Norbornene monomers can be used alone or in combination of two or more.

  Specifically, as means for obtaining such a norbornene-based polymer, a) a monomer that is polymerized to give a repeating unit of the structure of X and a monomer that is polymerized to give a repeating unit of the structure of Y A method of polymerizing by controlling the copolymerization ratio, and if necessary, hydrogenating unsaturated bonds in the polymer; b) having a polymer having the X structure as a repeating unit, and having the Y structure as a repeating unit The method of controlling by the blend ratio with a polymer is mentioned.

  The molecular weight of the alicyclic structure-containing polymer resin used in the present invention is a polyisoprene or polystyrene equivalent weight measured by gel permeation chromatography (hereinafter abbreviated as “GPC”) using cyclohexane as a solvent. The average molecular weight (Mw) is usually 8,000 to 100,000, preferably 10,000 to 80,000, more preferably 15,000 to 50,000. When the weight average molecular weight is in such a range, the mechanical strength and moldability of the film are highly balanced and suitable.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the alicyclic structure-containing polymer resin used in the present invention is not particularly limited, but is usually 1.0 to 10.0, preferably 1.0. It is -4.0, More preferably, it is the range of 1.2-3.5.

  The alicyclic structure-containing polymer resin that can be used in the present invention may contain a compounding agent. The compounding agent is not particularly limited, but is a layered crystal compound; inorganic fine particles; antioxidants, heat stabilizers, light stabilizers, weathering stabilizers, ultraviolet absorbers, near infrared absorbers and other stabilizers; lubricants, plastics Resin modifiers such as agents; Colorants such as dyes and pigments; Antistatic agents and the like. These compounding agents can be used alone or in combination of two or more, and the compounding amount is appropriately selected within a range not impairing the object of the present invention.

  Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc. Among them, phenolic antioxidants, particularly alkyl-substituted phenolic antioxidants are preferable. By blending these antioxidants, film coloring and strength reduction due to oxidative degradation during film formation can be prevented without lowering transparency, low water absorption and the like. These antioxidants can be used alone or in combination of two or more, and the blending amount thereof is appropriately selected within the range not impairing the object of the present invention, but the alicyclic structure-containing polymer. The amount is usually 0.001 to 5 parts by weight, preferably 0.01 to 1 part by weight based on 100 parts by weight of the resin.

  As the inorganic fine particles, those having an average particle diameter of 0.7 to 2.5 μm and a refractive index of 1.45 to 1.55 are preferable. Specific examples include clay, talc, silica, zeolite, and hydrotalcite. Among these, silica, zeolite, and hydrotalcite are preferable.

  The addition amount of the inorganic fine particles is not particularly limited, but is usually 0.001 to 10 parts by weight, preferably 0.005 to 5 parts by weight with respect to 100 parts by weight of the alicyclic structure-containing polymer resin.

  Examples of the lubricant include hydrocarbon lubricants; fatty acid lubricants; higher alcohol lubricants; fatty acid amide lubricants; fatty acid ester lubricants; metal soap lubricants. Of these, hydrocarbon lubricants, fatty acid amide lubricants and fatty acid ester lubricants are preferred. Further, among them, those having a melting point of 80 ° C. to 150 ° C. and an acid value of 10 mgKOH / mg or less are particularly preferable.

  When the melting point deviates from 80 ° C. to 150 ° C. and the acid value becomes larger than 10 mgKOH / mg, the haze value tends to decrease.

  The average thickness of the resin film (A) made of the alicyclic structure-containing polymer resin used in the present invention is 5 to 200 μm, preferably 30 to 100 μm.

  When the thickness is less than 5 μm, the mechanical strength as a protective film is lowered, and warpage or the like is likely to occur when the polarizing plate is placed in a high temperature and high humidity environment. When the thickness exceeds 200 μm, the light transmittance of the protective film is lowered, and further, the adhesive is not sufficiently dried when the films are adhered, and the durability of the polarizing film is lowered. Therefore, when the thickness of the resin film (A) is in the above range, a polarizing plate excellent in mechanical strength and durability can be obtained.

In addition, the resin film (A) has a moisture permeability at the above thickness of preferably 0.3 to 40 g / m ² · 24 hr, more preferably 0.6 to 10 g / m ² · 24 hr. If the moisture permeability is too low, drying of the adhesive becomes insufficient as described above, and if it is too high, the moisture absorption of the polarizer in the usage environment increases, and the durability of the polarizing plate decreases in any case. Is in the above range, the durability of the polarizing plate is improved. The moisture permeability is a value measured at a temperature of 40 ° C. and a humidity of 90% using a cup method according to JIS Z0280.

  In the present invention, the thickness variation of the resin film (A) is preferably within 3.0% of the average thickness, and more preferably within 2.5%. When the thickness of the resin film (A) is within the above range, color unevenness when the resin film (A) of the present invention is incorporated in a liquid crystal display device can be reduced.

  In the resin film (A) used in the present invention, the content of the volatile component of the resin film is preferably 0.1% by weight or less, more preferably 0.05% by weight or less. Due to the content of the volatile component within the above range, the dimensional change due to the use environment can be reduced, and the stability of the optical characteristics such as display non-uniformity does not occur even if used for a long time in a liquid crystal display. Excellent.

  The volatile component is a relatively low boiling point substance having a molecular weight of 200 or less contained in a trace amount in the resin film, and examples thereof include residual monomers and solvents. The content of the volatile component is the sum of the substances having a molecular weight of 200 or less contained in a small amount in the alicyclic structure-containing polymer resin, and can be quantified by analysis by gas chromatography.

  In the die line of the resin film (A) used in the present invention, the maximum depth of the die line formed in the longitudinal direction of the resin film is 50 nm or less, and the minimum width of the die line is 500 nm or more.

  The depth and width of the die line are determined by observing the interference fringes by scanning the uneven surface of the film from the bottom to the top at a constant speed using a three-dimensional structural analysis microscope (manufactured by Saigo Co., Ltd.). It can be measured.

  When the die line is within the above range, even when the die line is incorporated in a liquid crystal display unit having a high-brightness backlight unit, a bright display state can be obtained without any bright spots.

  Here, when measuring the depth and width from the top of the adjacent peak of the die line to the bottom of the valley, the base line 12 is drawn as shown in FIG. Measure the distance between the intersections of the lines 15 and 16 drawn perpendicularly to the baseline 12 and the baseline 12, and die line the sum of the distance from the top of the mountain to the baseline and the distance from the bottom of the valley to the baseline Of depth.

  In FIG. 3, the distance to the valley 13 on the left side of the vertex 14 and the distance to the next valley on the right side of the vertex 14 are also measured, and the distance and the next valley on the right side of the vertex 14 are measured. The total distance is defined as the width of the die line having the apex 14.

  In the present invention, the maximum value of in-plane retardation (Re) (hereinafter referred to as “Re”) of the resin film (A) is preferably 4 nm or less. When Re is 4 nm or less, color unevenness when incorporated in a liquid crystal display unit can be suppressed.

  Re can be obtained by Re = (nx + ny) × d, where nx and ny are the main refractive indexes in the film plane and d is the thickness of the film.

  In addition, retardation (Rth) (hereinafter referred to as “Rth”) in the film thickness direction is set to nx and ny as the main refractive index in the film plane, nz as the refractive index in the film thickness direction, and d as the film thickness. Assuming that (nm), Rth = {(nx + ny) / 2−nz} × d.

  Re and Rth in the film plane can be measured using a commercially available automatic birefringence meter (manufactured by Oji Scientific Instruments, “KOBRA-21ADH”).

  The resin film of the present invention can be obtained by molding by a solution casting method or a melt extrusion method, preferably a melt extrusion method.

  In this invention, it has a hard-coat layer (B) on a resin film (A). The hard coat layer (B) preferably has a high refractive index. By making the refractive index high, reflection such as reflection of external light can be prevented, and a polarizing plate having excellent scratch resistance and antifouling properties can be obtained. When the hard coat layer (B) itself is not a high refractive index, a high refractive index layer may be provided separately from the hard coat layer (B).

  Here, a high refractive index means a refractive index larger than the refractive index of the antireflection layer (C) laminated | stacked later, Preferably it is 1.55 or more.

The refractive index can be obtained by measuring using, for example, a known spectroscopic ellipsometer.
The material for forming the hard coat layer is not particularly limited as long as it shows a hardness of “HB” or higher in the pencil hardness test specified in JIS K5700. Examples thereof include organic hard coat materials such as organic silicone, melamine, epoxy, acrylic, and urethane acrylate; inorganic hard coat materials such as silicon dioxide; and the like. Of these, urethane acrylate-based and polyfunctional acrylate-based hard coat materials are preferably used from the viewpoint of good adhesive strength and excellent productivity.

  The formation method in particular of a hard-coat layer (B) is not restrict | limited, For example, an active energy ray curable resin coating liquid is apply | coated on the resin film (A) with a well-known coating method, and energy rays, such as an ultraviolet-ray, are used. Can be formed by irradiating and curing. The average thickness of the hard coat layer is 0.5 to 30 μm, preferably 3 to 15 μm.

By containing an active energy ray-curable resin, a high refractive index hard coat layer having sufficient strength, durability, adhesion, and transparency can be obtained. The active energy ray-curable resin is polymerized in the molecule. It is a resin obtained by curing a prepolymer, oligomer and / or monomer having a polymerizable unsaturated bond or an epoxy group by irradiation with active energy rays. An active energy ray refers to an electromagnetic wave or a charged particle beam having an energy quantum capable of polymerizing or crosslinking molecules, and usually an ultraviolet ray or an electron beam is used.

  Examples of prepolymers and oligomers having a polymerizable unsaturated bond or epoxy group in the molecule include unsaturated polyesters such as a condensation product of unsaturated dicarboxylic acid and polyhydric alcohol; polyester methacrylate, polyether methacrylate, polyol methacrylate And methacrylates such as melamine methacrylate, polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polyol acrylates, acrylates such as melamine acrylates, and cationic polymerization type epoxy compounds.

Examples of the monomer having a polymerizable unsaturated bond or epoxy group in the molecule include styrene monomers such as styrene and α-methylstyrene; methyl acrylate, ethyl acrylate, -2-ethylhexyl acrylate, methoxy acrylate Acrylic esters such as ethyl, butoxyethyl acrylate, butyl acrylate, methoxybutyl acrylate, and phenyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, methoxyethyl methacrylate, ethoxymethyl methacrylate, methacrylic acid Methacrylic acid esters such as phenyl and lauryl methacrylate; acrylic acid-2- (N, N-diethylamino) ethyl, acrylic acid-2- (N, N-dimethylamino) ethyl, acrylic acid-2- (N, N -Dibenzylamino) methyl, acrylic -2-(N, N-diethylamino) substituted amino alcohol esters of unsaturated substituted and propyl; acrylamide, unsaturated carboxylic acid amides such as methacrylamide;
Ethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, ethylene glycol diacrylate, propylene glycol dimethacrylate, diethylene glycol dimethacrylate 2-hydroxy acrylate, 2-hexyl acrylate, phenoxyethyl acrylate, ethylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate Multifunctional Acrela such as REIT G
And polythiols having two or more thiol groups in the molecule, such as trimethylolpropane trithioglycolate, trimethylolpropane trithiopropylate, and pentaerythritol tetrathioglycolate.

  In the present invention, these prepolymers, oligomers and / or monomers can be used singly or in combination of two or more.

  The content of the prepolymer, oligomer and / or monomer in the active energy ray curable resin to be used is preferably 5% by weight to 95% by weight from the viewpoint of obtaining excellent coating suitability.

  The hard coat layer preferably further contains inorganic oxide particles.

  By adding inorganic oxide particles, a hard coat layer having excellent scratch resistance and a refractive index of 1.55 or more can be easily formed.

  As the inorganic oxide particles that can be used for the hard coat layer (B), those having a high refractive index are preferable. Specifically, inorganic oxide fine particles having a refractive index of 1.7 or more, particularly 1.7 to 2.3 are preferable.

  Examples of such a high refractive index inorganic oxide include, for example, titania (titanium oxide), zirconia (zirconium oxide), zinc oxide, tin oxide, cerium oxide, antimony pentoxide, tin-doped indium oxide (ITO), Examples include tin oxide doped with antimony (ATO), indium oxide doped with zinc (IZO), zinc oxide doped with aluminum (AZO), and tin oxide doped with fluorine (FTO).

  Among these, antimony pentoxide is suitable as a component for adjusting the refractive index because it has a high refractive index and an excellent balance between conductivity and transparency.

  These inorganic oxide particles can be used singly or in combination of two or more.

  In order to prevent the transparency of the hard coat layer from being lowered, the inorganic oxide particles are so-called ultrafine particle sizes, more specifically, those having a primary particle diameter of 1 nm to 100 nm or less, preferably 1 nm to 50 nm or less. preferable.

  The primary particle diameter of the inorganic oxide particles may be visually measured from a secondary electron emission image photograph obtained by a scanning electron microscope (SEM) or the like, or a dynamic light scattering method or a static light scattering method may be used. Mechanical measurement may be performed by a particle size distribution meter to be used.

  If the primary particle diameter of the inorganic oxide particles is within the above range, the particle shape can be used in the present invention regardless of whether it is spherical, needle-shaped, or any other shape. In the case of a needle shape, the length is viewed as the particle diameter.

  Further, as the inorganic oxide particles that can be used in the present invention, at least a part of the surface thereof is coated with an organic compound or an organometallic compound having an anionic polar group in order to enhance dispersibility in an organic solvent. It is preferable that

  As the organic compound having an anionic polar group, those having an anionic polar group such as a carboxyl group, a phosphate group, or a hydroxyl group can be used. For example, stearic acid, lauric acid, oleic acid, linoleic acid, linolenic acid, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, ethylene oxide, modified phosphoric acid triacrylate, epichlorohydrin modified glycerol triacrylate, and the like can be given.

  Examples of the organometallic compound having an anionic polar group include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldiethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane Silane coupling agents such as vinyltris (2-methoxyethoxy) silane and 3-methacryloxypropyltrimethoxysilane; KR-TTS, KR-46B, KR-55, KR-41B, KR-38S, KR-138S, KR -238S, 338X, KR-44, KR-9S , KR-ET (above, titanate coupling agent manufactured by Ajinomoto Fine Techno Co., Ltd.), tetramethoxy titanium, tetraethoxy titanium, tetraisopropoxy titanium, tetra n-propoxy titanium, tetra n-butoxy titanium, tetra sec-butoxy And titanate coupling agents such as titanium and tetra-tert-butoxytitanium;

  Furthermore, the surface of the inorganic oxide particles is coated with an organic compound and / or an organometallic compound to impart hydrophobicity. Obtained by dissolving the organic compound and / or organometallic compound having an anionic polar group in an organic solvent, dispersing the inorganic oxide in the solution, and then completely evaporating and removing the organic solvent. Can do. Through this process, the dispersibility of the inorganic fine particles can be improved and re-aggregation can be prevented.

  Two or more inorganic oxide particles may be used in combination. In this case, a transparent thin film having a plurality of functions in a balanced manner can be formed by combining inorganic oxide particles having different main functions. For example, a predetermined refractive index is obtained by combining rutile-type titanium oxide fine particles having a very high refractive index but low conductivity and the above-described conductive inorganic oxide having extremely high conductivity but a refractive index smaller than that of rutile-type titanium oxide. It is possible to form a hard coat layer having good antistatic performance.

  Further, the amount of the inorganic oxide fine particles is not particularly limited, but from the viewpoint of easily obtaining a hard coat layer having excellent scratch resistance and a refractive index of 1.55 or more, an active energy ray curable resin. It is preferable that it is 40-90 weight part with respect to 100 weight part whole coating liquid.

  When the active energy ray-curable resin is cured by ultraviolet irradiation, a photopolymerization initiator or a photopolymerization accelerator is added. As photopolymerization initiators, radical polymerization initiators such as acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether; aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metathelone compounds, benzoin sulfonic acids Cationic polymerizable initiators such as esters; These can be used individually by 1 type or in combination of 2 or more types.

  The addition amount of the photopolymerization initiator is usually 0.1 to 10 parts by weight with respect to 100 parts by weight of the active energy ray-curable resin.

Further, an organic reactive silicon compound may be added to the active energy ray curable resin. Examples of organic reactive silicon compounds that can be used include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, and tetra-tert- Butoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylethoxysilane, dimethylmethoxysilane, dimethylpropoxysilane, dimethylbutoxysilane, methyldimethoxy silane, methyl diethoxy silane, hexyl trimethoxy silane, _{formula: R m Si (oR ')} n ( wherein, R and R' each independently represent an alkyl group having 1 to 10 carbon atoms, , N represents each independently satisfy the relationship of m + n = 4 is a positive integer) the organosilicon compound represented by.;
3- (2-aminoethyl) aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropylmethyldimethoxysilane, 3- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltriethoxysilane 3-methacryloxypropylmethoxysilane, N-3- (N-vinylbenzylaminoethyl) -3-aminopropylmethoxysilane / hydrochloride, 3-glycidoxypropyltrimethoxysilane, aminosilane, methylmethoxysilane, vinyltri Acetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, hexamethyldisilazane, vinyltris (3-methoxyethoxy) silane, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride, Le trichlorosilane, silane coupling agents such as dimethyldichlorosilane;
One-end vinyl group-substituted polysilane, both-end vinyl group-substituted polysilane, one-end vinyl group-substituted polysiloxane, both-end vinyl group-substituted polysiloxane, vinyl group-substituted polysilane obtained by reacting these compounds, or vinyl group-substituted poly Active energy ray-curable silicon compounds such as siloxane; other organosilicon compounds such as (meth) acryloxysilane compounds such as 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane And the like.

  The active energy ray-curable resin that can be used includes a prepolymer, an oligomer and / or a monomer having a polymerizable unsaturated bond or an epoxy group in the molecule, and optionally inorganic oxide particles in a suitable organic solvent. It can be prepared by dissolving or dispersing.

  Examples of the organic solvent that can be used in the active energy ray-curable resin coating solution include alcohols such as methanol, ethanol, isopropanol, n-butanol, and isobutanol; ethylene glycol, ethylene glycol monobutyl ether, and ethylene glycol monoacetate. Glycols such as ethyl ether, diethylene glycol, diethylene glycol monobutyl ether, diacetone glycol; aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as n-hexane and n-heptane; esters such as ethyl acetate and butyl acetate Ketones such as methyl ethyl ketone and methyl isobutyl ketone; oximes such as methyl ethyl ketoxime; and combinations of two or more thereof.

  The method for coating the active energy ray-curable resin on the resin film (A) is not particularly limited, and a known coating method can be employed. Examples of the coating method include a wire bar coating method, a dip method, a spray method, a spin coating method, and a roll coating method.

  After obtaining the coating film of the active energy ray curable resin, it can be dried and cured by irradiating the active energy ray to form a hard coat layer.

  The irradiation intensity and irradiation time of the active energy ray are not particularly limited, and irradiation conditions such as irradiation intensity and irradiation time can be appropriately set according to the active energy ray curable resin to be used.

Antireflection layer (C)
The antireflection layer (C) used in the present invention refers to a layer having a refractive index lower than that of the hard coat layer (B). The refractive index of the antireflection layer (C) may satisfy the above conditions, but is preferably 1.36 or less, more preferably 1.35 to 1.25, and 1.34 to 1.30. It is particularly preferred that By satisfying the above preferable conditions, an antireflection layer excellent in the balance between antireflection performance, scratch resistance and strength is formed.

  The low refractive index layer used in the optical laminated film of the present invention is not particularly limited as long as it is a material constituting a layer having a refractive index of 1.36 or less, but it is easy to control the refractive index and water resistance. In terms of superiority, airgel is preferred.

  The airgel is a transparent porous body in which minute bubbles are dispersed in a matrix. Most of the size of the bubbles is 200 nm or less, and the content of the bubbles is usually 10% by volume or more and 60% by volume or less, preferably 20% by volume or more and 40% by volume or less.

  Specific examples of the airgel in which minute bubbles are dispersed include silica aerogel and a porous body in which hollow particles are dispersed in a matrix.

  Silica airgel is a wet state composed of a silica skeleton obtained by hydrolysis polymerization reaction of alkoxysilane as disclosed in US Pat. No. 4,402,927, US Pat. No. 4,432,956, US Pat. No. 4,610,863 and the like. The gel-like compound can be produced by drying in a supercritical state above the critical point of the solvent in the presence of a solvent (dispersion medium) such as alcohol or carbon dioxide. In supercritical drying, for example, a gel compound is immersed in liquefied carbon dioxide, and all or part of the solvent contained in the gel compound is replaced with liquefied carbon dioxide having a critical point lower than that of the solvent. It can be carried out by drying under supercritical conditions of a single system of or a mixed system of carbon dioxide and a solvent. Silica airgel may be produced in the same manner as described above using sodium silicate as a raw material as disclosed in US Pat. No. 5,137,279, US Pat. No. 5,124,364, and the like.

  Here, as disclosed in JP-A-5-279011 and JP-A-7-138375, the gel-like compound obtained by hydrolysis and polymerization reaction of alkoxysilane as described above is hydrophobized. It is preferable to impart hydrophobicity to the silica airgel. Hydrophobic silica airgel imparted with hydrophobicity as described above can prevent moisture, water, and the like from entering, and prevent the performance of the silica airgel from being degraded in refractive index, light transmittance, and the like.

  This hydrophobization treatment step can be performed before or during supercritical drying of the gel compound. The hydrophobization treatment is performed to make the hydrophobization by reacting the hydroxyl group of the silanol group present on the surface of the gel compound with the functional group of the hydrophobization treatment agent and replacing it with the hydrophobic group of the hydrophobization treatment agent. . As a method of performing the hydrophobization treatment, the gel is immersed in a hydrophobization treatment solution in which the hydrophobization treatment agent is dissolved in a solvent, mixed, and so on. There is a method in which the hydrophobization reaction is performed by heating accordingly.

  Examples of the solvent used for the hydrophobic treatment include methanol, ethanol, isopropanol, xylene, toluene, benzene, N, N-dimethylformamide, hexamethyldisiloxane, and the like, but the hydrophobic treatment agent can be easily dissolved. And what is necessary is just to be able to substitute for the solvent which the gel before hydrophobization treatment contains, and it is not limited to these. Further, when supercritical drying is performed in a later step, a medium that can be easily supercritically dried, such as methanol, ethanol, isopropanol, liquefied carbon dioxide, or the like, is preferable. Examples of the hydrophobizing agent include hexamethyldisilazane, hexamethyldisiloxane, trimethylmethoxysilane, dimethyldimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, trimethylethoxysilane, dimethyldiethoxysilane, and methyltriethoxysilane. Etc.

  The refractive index of silica airgel can be freely changed by the raw material compounding ratio of silica airgel.

  The formation method of the antireflection layer (C) made of silica aerogel is not particularly limited. For example, the gel-like compound is coated on the hard coat layer by a known coating method, and the supercritical drying is performed. The method of forming by performing is mentioned. Further, the hydrophobization treatment may be performed before or during supercritical drying. In the supercritical drying, for example, the gel compound is immersed in liquefied carbon dioxide, and all or a part of the solvent containing the gel compound is replaced with liquefied carbon dioxide having a lower critical point than the solvent. It can be carried out by drying under supercritical conditions of a single system of carbon dioxide or a mixed system of carbon dioxide and a solvent.

  As a porous material in which hollow fine particles are dispersed in a matrix, hollow fine particles having voids inside fine particles as disclosed in JP-A Nos. 2001-233611 and 2003-149642 are used as binder resins. And a porous material dispersed in the substrate.

  The binder resin can be selected from resins that meet conditions such as dispersibility of hollow fine particles, transparency of the porous body, and strength of the porous body. For example, conventionally used polyester resins and acrylic resins can be used. Resin, urethane resin, vinyl chloride resin, epoxy resin, melamine resin, fluorine resin, silicone resin, butyral resin, phenol resin, vinyl acetate resin, UV curable resin, electron beam curable resin, emulsion resin, water-soluble resin, hydrophilic resin Further, a mixture of these resins, a coating resin such as a copolymer or a modified product of these resins, a hydrolyzable organosilicon compound such as alkoxysilane, and a hydrolyzate thereof can be used.

  Among these, hydrolyzable organosilicon compounds such as acrylic resins, epoxy resins, urethane resins, silicone resins, alkoxysilanes and hydrolysates thereof are preferred from the viewpoint of the dispersibility of the fine particles and the strength of the porous body.

The hydrolyzable organosilicon compound such as alkoxysilane and the hydrolyzate thereof are formed from one or more compounds selected from the group consisting of the following (a) to (c), and in the molecule: -(O-Si) _m -O- (wherein _m represents a natural number) has a bond.

(A) A compound represented by formula (1): SiX ₄ .

(B) At least one partial hydrolysis product of the compound represented by the formula (1).

(C) At least one complete hydrolysis product of the compound represented by the formula (1).

  In the formula (1), X is a halogen atom such as a chlorine atom or a bromine atom; a monovalent hydrocarbon group which may have a substituent; an oxygen atom; an organic acid radical such as an acetate radical or a nitrate radical; A 3-diketonate group such as acetonate; an inorganic acid group such as nitrate or sulfate; an alkoxy group such as methoxy, ethoxy, n-propoxy, or n-butoxy; or a hydroxyl group.

  Examples of the monovalent hydrocarbon group which may have a substituent include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group; a cyclopentyl group, A cycloalkyl group such as a cyclohexyl group; an aryl group optionally having a substituent such as a phenyl group, a 4-methylphenyl group, a 1-naphthyl group, and a 2-naphthyl group; an alkenyl group such as a vinyl group and an aryl group; Aralkyl groups such as benzyl group, phenethyl group and 3-phenylpropyl group; haloalkyl groups such as chloromethyl group and 3-chloropropyl group; 3,3,3-trifluoropropyl group, methyl-3,3,3-tri Perfluoroalkyl groups such as fluoropropyl group, heptadecafluorodecyl group, trifluoropropyl group, tridecafluorooctyl group An alkenylcarbonyloxyalkyl group such as a 3-methacryloxypropyl group; an alkyl group having an epoxy group such as a 3-glycidoxypropyl group or a 3,4-epoxycyclohexylethyl group; a mercapto group such as a 3-mercaptopropyl group Examples thereof include an alkyl group; an alkyl group having an amino group such as a 3-aminopropyl group; and the like. Among these, an alkyl group having 1 to 4 carbon atoms, a perfluoroalkyl group, and a phenyl group are preferable because of easy synthesis, easy availability, and low reflection characteristics.

Among these compounds (a), formula (2): R _a SiY _4-a [wherein, R represents a monovalent hydrocarbon group which may have a substituent, and a represents 0-2. Represents an integer, and when a is 2, R may be the same or different. Y represents a hydrolyzable group, and Y may be the same or different. ] The silicon compound represented by this is preferable.

In the formula (2), Y represents a hydrolyzable group. Here, the hydrolyzable group refers to a group that is hydrolyzed in the presence of an acid or a base catalyst as desired to form a — (O—Si) _m —O— bond.

  Specific examples of the hydrolyzable group include alkoxy groups such as methoxy group, ethoxy group and propoxy group; acyloxy groups such as acetoxy group and propionyloxy group; oxime group (—O—N═C—R ′ (R ″) )), Enoxy group (—O—C (R ′) ═C (R ″) R ′ ″), amino group, aminoxy group (—O—N (R ′) R ″), amide group (— N (R ′) — C (═O) —R ″) and the like. In these groups, R ′, R ″, and R ′ ″ each independently represent a hydrogen atom or a monovalent hydrocarbon group. Among these, Y is preferably an alkoxy group from the viewpoint of availability.

 The silicon compound represented by the formula (2) is preferably a silicon compound in which a is an integer of 0 to 2 in the formula (2). Specific examples thereof include alkoxysilanes, acetoxysilanes, oxime silanes, enoxysilanes, aminosilanes, aminoxysilanes, amidosilanes and the like. Among these, alkoxysilanes are more preferable because of their availability.

  In the formula (2), examples of the tetraalkoxysilane in which a is 0 include tetramethoxysilane and tetraethoxysilane. Examples of the organotrialkoxysilane in which a is 1 include methyltrimethoxysilane and methyltriethoxy. Examples include silane, methyltriisopropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, and the like. Examples of the diorganodialkoxysilane in which a is 2 include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane.

 The molecular weight of the compound represented by the formula (1) is not particularly limited, but is preferably 40 to 300, and more preferably 100 to 200.

 At least one partial hydrolysis product (hereinafter referred to as “compound (3)”) of the compound represented by formula (1) of (b), and represented by formula (1) of (c). At least one complete hydrolysis product of the compound (hereinafter referred to as “compound (4)”) is obtained by completely or partially hydrolyzing one or more of the compounds represented by the formula (1). Can be obtained by condensation.

Compound (3) and compound (4) are, for example, a metal tetraalkoxide represented by Si (Or) ₄ (r represents a monovalent hydrocarbon group) and a molar ratio [H ₂ O] / [Or ] Can be obtained by hydrolysis in the presence of water in an amount of 1.0 or more, 1.0 to 5.0, preferably 1.0 to 3.0. Hydrolysis can be performed by stirring the whole volume at a temperature of 5 to 100 ° C. for 2 to 100 hours.

  When hydrolyzing the compound represented by the formula (1), a catalyst may be used as necessary. The catalyst to be used is not particularly limited, but the obtained partial hydrolyzate and / or complete hydrolyzate is likely to have a two-dimensional cross-linked structure, the condensed compound is easily made porous, and hydrolysis. From the viewpoint of shortening the time required for this, an acid catalyst is preferred.

 The acid catalyst used is not particularly limited. For example, acetic acid, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid, malonic acid, toluenesulfonic acid, Organic acids such as acids; inorganic acids such as hydrochloric acid, nitric acid, and halogenated silane; acidic sol-like fillers such as acidic colloidal silica and oxidized titania sol; These acid catalysts can be used alone or in combination of two or more.

  Instead of the acid catalyst, a base catalyst such as an aqueous solution of an alkali metal or alkaline earth metal hydroxide such as sodium hydroxide or calcium hydroxide, an aqueous ammonia or an aqueous solution of amines may be used.

  The molecular weights of the compound (3) and the compound (4) are not particularly limited, but usually the weight average molecular weight is in the range of 200 to 5,000.

  The hollow fine particles are not particularly limited as long as they are fine particles of an inorganic compound, but inorganic hollow fine particles in which cavities are formed inside the outer shell are preferable, and use of silica-based hollow fine particles is particularly preferable.

As the inorganic compound, an inorganic oxide is common. As the inorganic _{oxide, SiO 2, Al 2 O 3} , B 2 O 3, TiO 2, ZrO 2, SnO 2, Ce 2 O 3, P 2 O 5, Sb 2 O 3, MoO 3, ZnO 2, WO One or two or more of ₃ or the like can be mentioned. Examples of the two or more inorganic oxides include TiO ₂ —Al ₂ O ₃ , TiO ₂ —ZrO ₂ , In ₂ O ₃ —SnO ₂ , and Sb ₂ O ₃ —SnO ₂ . These can be used alone or in combination of two or more.

  The inorganic hollow fine particles include (a) a single layer of an inorganic oxide, (b) a single layer of a composite oxide composed of different types of inorganic oxides, and (c) a double layer of (a) and (b) above. What is included can be used.

  The outer shell may be porous with pores, or the pores may be closed and the cavity sealed with respect to the outside of the outer shell. The outer shell is preferably a plurality of inorganic oxide coating layers comprising an inner first inorganic oxide coating layer and an outer second inorganic oxide coating layer. By providing the second inorganic oxide coating layer on the outer side, the fine pores of the outer shell can be closed to make the outer shell dense, and furthermore, inorganic hollow fine particles in which the inner cavity is sealed can be obtained. In particular, when a fluorine-containing organosilicon compound is used for forming the second inorganic oxide coating layer, the coating layer containing fluorine atoms is formed, so that the resulting particles have a lower refractive index and are reduced to an organic solvent. The dispersibility is good, and further, it is effective for imparting antifouling property to the low refractive index layer, which is preferable. Such fluorine-containing organic silicon compounds include 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, heptadecafluorodecylmethyldimethoxysilane, heptadecafluorodecyl. Examples thereof include trichlorosilane, heptadecafluorodecyltrimethoxysilane, trifluoropropyltrimethoxysilane, and tridecafluorooctyltrimethoxysilane.

  The thickness of the outer shell is preferably in the range of 1 to 50 nm, particularly 5 to 20 nm. If the thickness of the outer shell is less than 1 nm, the inorganic hollow fine particles may not maintain a predetermined particle shape. On the other hand, when the thickness of the outer shell exceeds 50 nm, the cavities in the inorganic hollow fine particles are small, and as a result, the ratio of the cavities may be reduced and the refractive index may not be sufficiently lowered.

  When the first inorganic oxide coating layer and the second inorganic oxide coating layer are provided as outer shells as described above, the total thickness of these layers may be in the range of 1 to 50 nm. In particular, in the case of a densified outer shell, the thickness of the second inorganic oxide coating layer is preferably in the range of 20 to 40 nm.

Further, the solvent used when preparing the inorganic hollow fine particles and / or a gas that permeates when drying may be present in the cavities, but the average particle diameter of the inorganic hollow fine particles is not particularly limited, but is preferably 5 to 2000 nm, ˜100 nm is more preferable. If it is smaller than 5 nm, the effect of lowering the refractive index tends to be small. Conversely, if it is larger than 2000 nm, the transparency is deteriorated and the contribution due to diffuse reflection tends to be large. Here, the average particle diameter is a number average particle diameter by observation with a transmission electron microscope.

  The inorganic hollow fine particles that can be used in the present invention can be produced, for example, based on the method described in detail in JP-A No. 2001-233611, and commercially available inorganic hollow fine particles can also be used.

  The blending amount of the inorganic hollow fine particles is not particularly limited, but is preferably 10 to 30% by weight with respect to the whole antireflection layer (C). When the blending amount of the inorganic hollow fine particles is within this range, a laminated film having both antireflection properties and scratch resistance can be obtained.

  When the antireflection layer (C) is a porous body in which hollow particles are dispersed in a matrix, the formation method is not particularly limited. For example, the antireflection layer (C) contains hollow fine particles and a binder resin on the hard coat layer. The coating liquid which becomes is apply | coated by the well-known coating method, and the method of performing a drying and heat processing as needed is mentioned. The temperature of the heating performed as necessary is usually 50 to 200 ° C, preferably 80 to 150 ° C.

  In the present invention, the average thickness of the antireflection layer (C) is 10 to 1000 nm, preferably 30 to 500 nm.

  In the polarizing plate of the present invention, an antifouling layer can be further formed on the antireflection layer (C) in order to improve the antifouling performance of the antireflection layer (C) on the resin film (A) side.

  The material for forming the antifouling layer is not particularly limited as long as the function of the antireflection layer is not hindered and the required performance as the antifouling layer is satisfied. Usually, a compound having a hydrophobic group can be preferably used.

As specific examples, a perfluoroalkylsilane compound, a perfluoropolyethersilane compound, or a fluorine-containing silicone compound can be used. As the method for forming the antifouling layer, for example, a physical vapor deposition method such as vapor deposition or sputtering; a chemical vapor deposition method such as CVD; a wet coating method; The thickness of the antifouling layer is not particularly limited, but is usually preferably 20 nm or less, and more preferably 1 to 10 nm.
FIG. 1 shows the configuration of the upper part of the polarizer when the antireflection layer (C) 3 of the present invention is viewed from the viewing side. In the figure, a laminate 1 is shown in which a hard coat layer (B) 3 and an antireflection layer (C) 4 are laminated on a resin film (A) 2.

Resin film (D)
The resin film (D) used for the polarizing plate of the present invention comprises an alicyclic structure-containing polymer resin, and has a thickness of 5 to 200 μm and a moisture permeability of 0.3 to 40 g / m ² · 24 h. Examples of the alicyclic structure-containing polymer resin include the same ones that can be used for the resin film (A).

  The average thickness of the resin film (D) made of the alicyclic structure-containing polymer resin of the present invention is usually 5 to 200 μm, preferably 30 to 100 μm.

  When the thickness is less than 5 μm, the mechanical strength as a protective film is lowered, and warpage or the like is likely to occur when the polarizing plate is placed in a high temperature and high humidity environment. When the thickness exceeds 200 μm, the light transmittance of the protective film is lowered, and further, the adhesive is not sufficiently dried when the films are bonded to each other, so that the durability of the polarizer is lowered. Therefore, when the thickness of the resin film (D) is in the above range, a laminate having excellent mechanical strength and durability can be obtained.

The resin film (D) has a moisture permeability of preferably 0.3 to 40 g / m ² · 24 hr, more preferably 0.6 to 20 g / m ² · 24 hr. If the moisture permeability is too low, drying of the adhesive is insufficient as described above, and if it is too high, moisture absorption of the polarizing film in the use environment increases, and the durability of the polarizing film decreases in any case. Is in the above range, the durability of the polarizing film is improved. The moisture permeability is a value measured at a temperature of 40 ° C. and a humidity of 90% using a cup method according to JIS Z0280.

  The resin film (D) is preferably a film having retardation. There is no restriction | limiting in particular in the value of the retardation of a resin film (D).

  For example, a material that provides a half retardation with respect to a predetermined wavelength functions as a half-wave plate. What gives a quarter retardation functions as a quarter wave plate.

  A film made of another resin may be further laminated on the resin film (D). For example, when the film (D) is a ¼ wavelength plate, a broadband ¼ wavelength plate can be obtained by laminating a ½ wavelength plate on the film (D).

  As another aspect of the resin film (D), one having retardation in any one of (1) to (4) can be mentioned.

nx≈ny <nz (1)
nx≈ny> nz (2)
nx> ny≈nz (3)
nx≈nz> ny (4)
nx, ny, and nz represent refractive indexes in the X-axis, Y-axis, and Z-axis directions in the retardation plate or the like, and the X-axis direction is a direction in which the refractive index in the plane of the layer is maximized. (In-plane slow axis direction), and the Y-axis direction is a direction (in-plane fast axis direction) perpendicular to the X-axis direction in the plane of the layer, and the Z-axis direction is The thickness direction of the layer is perpendicular to the X-axis direction and the Y-axis direction.

  In the resin film (D) of the present invention, a plurality of retardation films may be laminated such that each slow axis intersects at a predetermined angle. When laminating, a known laminating method may be used. Moreover, you may use an adhesive etc. in the case of lamination | stacking.

  In the present invention, the thickness variation of the resin film (D) is preferably within 3.0% of the average thickness, and more preferably within 2.5%. The thickness variation was determined by the method described later.

  By setting the thickness variation of the resin film (D) within the above range, color unevenness when the resin film (D) of the present invention is incorporated in a liquid crystal display device can be reduced.

  The surface of the resin film (D) can be roughened as necessary. The means for roughening is not particularly limited, and examples thereof include corona discharge treatment, sand blasting, etching, and fine particle adhesion. Adhesion can be improved by roughening the surface of the resin film (D).

Primer layer The polarizing plate of this invention may provide a primer layer between a polarizer and the said resin film (A), and between a polarizer and the said resin film (D). By providing the primer layer, adhesion with the polarizer is improved, and mechanical strength, durability of the polarizer, and optical characteristics are improved.

  Examples of the primer layer include a vinyl alcohol polymer layer, a silicone layer, a urethane layer, a primer layer containing a conjugated diene polymer having a cyclized structure therein or a hydrogenated product thereof, and the like. . From the viewpoint of reliability, mechanical strength, optical properties, etc., a layer made of a vinyl alcohol polymer or a primer layer containing a conjugated diene polymer having a cyclized structure inside or a hydrogenated product thereof is preferable. A layer made of coalescence is most preferred.

  A vinyl alcohol polymer (sometimes referred to as PVA) is a generally known polymer. This PVA is obtained by, for example, polymerizing a vinyl monomer mainly composed of a vinyl ester monomer by a conventionally known method to produce a vinyl ester polymer (that is, a vinyl ester monomer homopolymer, two or more kinds). A vinyl ester monomer copolymer and a copolymer of a vinyl ester monomer and another ethylenically unsaturated monomer), and then saponifying the vinyl ester polymer by a conventional method. Is obtained. The saponification degree of the PVA used in the present invention is preferably 70 to 99%, and the polymerization degree is 200 to 3000. The PVA used in the present invention may be one in which, for example, acrylic acid, crotonic acid, itaconic acid and the like are copolymerized to a few mol% within a range that does not impair the object of the present invention. Further, a compound having an epoxy group, a carbonyl group, a silanol group, a thiol group, or the like may be modified by graft addition or the like.

  In the primer layer, for example, a curing agent; a coupling agent such as a silane coupling agent and a titanium coupling agent; terpene resin, phenol resin, terpene-phenol resin, rosin resin, xylene Tackifiers such as resins; inorganic fillers such as calcium carbonate, clay, titanium oxide, and carbon black; thixotropic agents such as aerosil and disbaron; UV absorbers, antioxidants, heat stabilizers, hydrolysis stabilizers A stabilizer such as may be contained.

  The average thickness of the primer layer is preferably from 0.01 to 20 μm, more preferably from 0.05 to 10 μm. When the thickness is less than 0.01 μm, it becomes difficult to control the thickness, and when it exceeds 20 μm, the durability of the polarizing film is lowered.

    The method for forming the primer layer is not particularly limited, and examples thereof include a method in which a primer layer forming coating solution is applied on a resin film by a known coating method. The thickness of the primer layer is not particularly limited, but is usually 0.01 to 5 μm, preferably 0.1 to 2 μm.

  Although the polarizing plate of this invention is not specifically limited by the manufacturing method, a hard-coat layer (B) and an antireflection layer (C) are laminated | stacked beforehand on a resin film (A), and then the resin film (A) becomes an inner side. Thus, it is preferable to overlap the polarizer and laminate the resin film (D) on the other surface of the polarizer.

In the lamination method using the primer layer, a solution containing the components of the primer layer is applied, and the hard coat layer (B) and the antireflection layer (C) are laminated on both sides of the polarizer before the coating film is dried. The resin film (A) and the resin film (D) are bonded together, and then the solvent is removed and bonded (hereinafter referred to as “wet lamination”),
And after apply | coating the solution containing the component of a primer layer, and removing a solvent and drying a coating film, the said hard-coat layer (B) and antireflection layer (C) were laminated | stacked on both surfaces of the polarizer here. Examples include a method of bonding the resin film (A) and the resin film (D) and bonding them by pressurization and / or heating (hereinafter referred to as “dry lamination”).

  In the case of wet lamination, the solution is applied or dropped onto a polarizing film or / and film with a Meyer bar, gravure coater, microgravure coater, etc., and the solvent is removed by heating while laminating the laminate with two rolls, for example. To do.

  In the case of dry lamination, the solution is applied to the polarizing film or / and the film with a bar coater, roll coater, gravure coater or the like, and the solvent in the coating film is removed using means such as passing through a drying furnace.

  In the above, the type of the intervening primer layer and the method of laminating the resin film on the polarizer include the polarizer, the resin film (A) in which the hard coat layer (B) and the antireflection layer (C) are laminated. And between the polarizing plate and the resin film (D).

  In the present invention, when the resin film (A) and the resin film (D) in which the hard coat layer (B) and the antireflection layer (C) are laminated on a polarizer are bonded together, a vinyl alcohol polymer is used. It is preferable to produce a laminate by wet lamination using the above solution. In that case, the viscosity of the vinyl alcohol polymer solution used is preferably in the range of 10 to 20,000 cP (centipoise), more preferably 100 to 12,000 cP. When the pressure is less than 10 cP, the solution flows excessively out of the laminate due to pressurization during lamination, and the thickness of the adhesive layer is reduced. On the other hand, when the pressure exceeds 20,000 cP, the coating property is deteriorated.

  In wet lamination, it is preferable to use water as the solvent because the adhesive strength between the layers of the laminate is excellent.

  In any of wet lamination and dry lamination, lamination of each film and a polarizer may be performed by any known means, but is preferable because it is easy to use a nip roll and is excellent in productivity. As the nip roll, a rubber roll and a metal roll, or a rubber roll and a rubber roll can be combined. The pressure at the time of lamination is usually 1 to 100 kgf / cm, preferably 3 to 30 kgf / cm in terms of nip line pressure.

  By curing the polarizing plate obtained by the above method, the adhesive strength between the polarizer and each film and the durability of the polarizer can be improved, and the warpage of the polarizing plate in a high temperature and high humidity environment can be reduced. The curing conditions are such that the temperature is preferably 2 to 150 ° C, more preferably 20 to 80 ° C, and the holding time is 0.5 to 200 hours, preferably 48 to 100 hours. When the curing temperature and holding time are within the above ranges, a polarizing film excellent in durability, optical performance and the like can be obtained.

  Moreover, after bonding each film and a polarizer through a primer layer, it is preferable to control the thickness of a primer layer by applying a pressure to this.

  In the polarizing plate of the present invention, the reflectance of the surface on which the resin film (A), the hard coat layer (B) and the antireflection layer (C) are sequentially laminated is usually 0.7% or less, preferably 0.5%. It is as follows. The reflectance can be obtained as a reflectance at a wavelength of 550 nm by measuring a reflection spectrum at a predetermined incident angle using a known spectrophotometer, for example.

  The surface on the antireflection layer (C) side of the polarizing plate of the present invention is excellent in scratch resistance. For example, even after a test (steel wool test) in which the surface of the antireflection layer (C) side of the polarizing plate is rubbed 10 times with a load of 0.025 MPa applied to steel wool, No scratches are observed on the film surface.

  The polarizing plate of the present invention is installed on the viewing side of the liquid crystal cell with the antireflection layer (C) side facing the viewing side, and can be suitably used for the following liquid crystal display device.

  FIG. 2 shows a panel configuration of the liquid crystal display device. The liquid crystal display device is composed of polarizing plates 5 and 9 disposed in a cell 7 in which liquid crystal is enclosed and perpendicular to the transmission axis (crossed Nicols) sandwiching it, and retardation films 5 and 8 for optical compensation. Further, the outermost part is composed of a hard coat layer, an antireflection layer, and an antifouling layer 1.

  The liquid crystal mode used in the liquid crystal cell includes an in-plane switching (IPS) mode, a vertical alignment (VA) mode, a multi-domain vertical alignment (MVA) mode, a continuous spin wheel alignment (CPA) mode, and a twisted nematic (TN) mode. , Super twisted nematic (STN) mode, hybrid alignment nematic (HAN) mode, and optically compensated bend (OCB) mode.

  The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. Parts and% are based on weight unless otherwise specified.

Evaluation in this example is performed by the following method.

(1) Depth and width of die line Measured by using a three-dimensional structural analysis microscope (manufactured by Saigo Co., Ltd.) and observing interference fringes by scanning the uneven surface of the film from bottom to top at a constant speed. .

  As shown in FIG. 3, a line 15 is drawn by drawing a baseline 12 to the bottom of the adjacent valley and the peak of the mountain, and perpendicularly extending from the peak 14 of the mountain or the bottom 13 of the valley to the baseline 12 and The distance between the intersections of 16 and the baseline 12 is measured, and the sum of the distance from the peak to the baseline and the distance from the valley bottom to the baseline is defined as the die line depth.

  The width of the die line is the same as the distance to the valley 13 on the left side of the vertex 14 and the distance to the next valley on the right side of the vertex 14. The total distance is defined as the width of the die line having the apex 14.

(2) Film thickness (average thickness and thickness variation)
A contact-type web thickness meter (RC-101 rotary caliper meter, manufactured by Meisho Co., Ltd.) is installed on a 1350 mm width resin film, and the thickness meter is moved sideways at intervals of 0.48 mm in the width direction of the resin film. taking measurement. The arithmetic average value (average thickness), maximum thickness, and minimum thickness of the measured values were obtained. What percentage of the average thickness is the maximum thickness or the difference between the minimum thickness and the average thickness was determined as the thickness variation.

(3) Moisture permeability The moisture permeability of the film was measured at a temperature of 40 ° C and a humidity of 90% using a cup method according to JIS Z0280.

(4) In-plane (Re), thickness direction (Rth)
(Re) in the film plane can be obtained by Re = (nx−ny) × d, where the main refractive index in the film plane is nx and ny, and the thickness of the film is d (nm).

  Further, (Rth) in the film thickness direction is defined as Rth = {, where the main refractive index in the film plane is nx, ny, the refractive index in the film thickness direction is nz, and the thickness of the film is d (nm). (Nx + ny) / 2−nz} × d.

  The value was measured using an automatic birefringence meter [manufactured by Oji Scientific Instruments, KOBRA-21ADH].

(5) Polarizing plate pencil hardness It measured with a 500-g load according to JIS-K5600.

(6) Polarizing plate reflectance (%)
Using a spectrophotometer (manufactured by JASCO Corporation, UV-visible near-infrared spectrophotometer V-750), the reflection spectrum was measured at an incident angle of 5 degrees, and the reflectance at a wavelength of 550 nm was determined.

(7) Total light transmittance Measured using “turbidimeter NDH-300A” manufactured by Nippon Denshoku Industries Co., Ltd. according to ASTM D1003. In addition, the same measurement is performed 5 times and the arithmetic average value is set as a representative value of the total light transmittance.

(8) Polarizing plate steel wool test The surface of the antireflection layer of the polarizing plate was rubbed 10 times in a state where a load of 0.025 MPa was applied to steel wool # 0000, followed by microscopic observation and evaluation with the following index.

○: No scratches Δ: Slight scratches ×: Many conspicuous scratches (9) Heat resistance test A polarizing plate (50 cm ² ) is placed in an oven at a temperature of 60 ° C. and a humidity of 90% and left for 500 hours to observe changes in the polarizing plate. did.

○: No change Δ: Warpage is observed at both ends ×: Strain is generated at both ends (10) Evaluation of display performance Commercially available liquid crystal television (the polarizing plates of Example 1 and Comparative Example 1 are MVA mode 20V type) Remove the liquid crystal display panel from the IPS mode 20V type liquid crystal television of Example 2 and Comparative Example 2 using the liquid crystal television), and on the viewing side of the polarizing plate and the viewing angle compensation film sandwiching the liquid crystal cell Remove the installed polarizing plate and viewing angle compensation film,
Instead, the polarizing plates used in Examples and Comparative Examples were bonded to the liquid crystal cell, and the liquid crystal display panel was reassembled and installed in the original liquid crystal television.

  A white character is displayed with a black background, and the line of sight is moved up and down, left and right from the front, and the angle at which the white character cannot be read is measured.

(11) Frame failure (color unevenness) evaluation The liquid crystal display device produced in (10) was darkly displayed, the entire display screen was observed from the front in a dark room, and evaluated according to the following indices.

○: A uniform black display as a whole and no light leakage.

Δ: Color unevenness of dark display is seen on the top, bottom, left and right of the frame

X: Light leakage is observed on the top, bottom, left and right of the frame.

(12) Bright spot defect evaluation The liquid crystal display device produced in 10 was darkly displayed, and the entire display screen was observed from the front in the dark room, and the number of bright spots was counted.

(Preparation of hard coat agent)
Antimony pentoxide modified alcohol sol (solid content concentration 30%, produced by Catalytic Chemical Co., Ltd.), UV curable urethane acrylate purple light UV7000B (produced by Nippon Synthetic Chemical Co., Ltd.) and photoinitiator Irgacure -184 (Ciba Geigy Co., Ltd.) 0.4 part was mixed to obtain a UV curable hard coat agent.

(Preparation of primer solution)
Hydrogenated maleic anhydride-modified styrene / butadiene / styrene block copolymer (Asahi Kasei Co., Ltd., Tuftec M1913, melt index value at 200 ° C. under 5 kg load, 1.0 g / 10 min, styrene block content 30 parts 2 parts of a hydrogenation rate of 80 parts or more and maleic anhydride addition amount 2%) are dissolved in a mixed solvent of 8 parts of xylene and 40 parts of methyl isobutyl ketone, and filtered through a polytetrafluoroethylene filter having a pore size of 1 μm. Only the complete solution was prepared as a primer solution.

(Adjustment of coating solution for antireflection layer)
An oligomer of tetramethoxysilane (“Methyl silicate 51” manufactured by Colcoat Co., Ltd.), methanol, water, and 0.01N hydrochloric acid aqueous solution were mixed at a mass ratio of 21: 36: 2: 2, and this was mixed at 25 ° C. The mixture was stirred in a high-temperature bath for 2 hours to adjust the weight average molecular weight to 850, and a silicone resin was obtained.

  Next, hollow silica isopropanol dispersion sol (manufactured by Catalytic Chemical Industry Co., Ltd., solid content 20%, average primary particle diameter of about 35 nm, outer shell thickness of about 8 nm) is added to the silicone resin as hollow silica fine particles, A silicone resin (condensed compound equivalent) is blended so that the weight ratio is 8: 2 on a solid basis, and then diluted with methanol so that the total solid content is 1%. Prepared.

(Production Example 1)
A resin film (A1) having a width of 1350 mm and an average thickness of 40 μm made of an alicyclic structure-containing polymer (ZEONOR 1420, manufactured by Nippon Zeon Co., Ltd .; glass transition temperature Tg 136 ° C.) was used. This resin film has the following characteristics.

When the film was cut into 50 cm ² and the die line was measured according to the evaluation (1), the maximum depth of the die line was 35 nm and the minimum width was 800 nm.

  When the thickness variation was measured according to the evaluation (2), it was 1.9%.

The film had a water vapor transmission rate of 3.2 g / m ² · 24 hr.

  The maximum value in the plane was 1.3 nm.

  This resin film was subjected to a corona discharge treatment for 3 seconds using a high-frequency transmitter (corona generator HV05-2, manufactured by Tamtec). The surface tension was 0.072 N / m.

Then, a hard coat agent is applied onto the resin film (A1) using a die coater, dried at 80 ° C. for 5 minutes, and then irradiated with ultraviolet rays (integrated light amount 300 mJ / cm ² ) to cure the hard coat agent. A resin film (A2) having a hard coat layer (B1) with a thickness of 5 μm was obtained.

  Further, a resin having an antireflection layer (C1) having a thickness of 200 μm is applied by coating an antireflection coating solution on the hard coat layer (B1) side surface of the film (A2) and heat-treating the coating at 120 ° C. for 10 minutes A film (A3) was obtained.

(Production Example 2)
A resin film (A4) made of an alicyclic structure-containing polymer resin and having a width of 1350 mm and an average thickness of 40 μm was used.

When the film was cut into 50 cm ² and the die line was measured according to Evaluation (1), the maximum depth of the die line was 190 nm and the minimum width was 300 nm.

  When the thickness variation was measured according to Evaluation (2), it was 2.1%.

The moisture permeability was 3.8 g / m ² · 24 hr.

  The maximum value in the plane was 2.9 nm.

  The resin film was subjected to a corona discharge treatment for 3 seconds using a high-frequency transmitter (corona generator HV05-2, manufactured by Tamtec). The surface tension was 0.072 N / m.

Furthermore, the hard coat agent was continuously applied on the resin film using a die coater. Next, after drying at 80 ° C. for 5 minutes, ultraviolet irradiation (accumulated light amount: 300 mJ / cm ² ) is performed to cure the hard coat agent to obtain a resin film (A5) having a hard coat layer (B2) having a thickness of 5 μm. It was.

  Further, a coating solution for forming an antireflection layer was applied to the surface of the film (A5) on the hard coat layer (B2) side, and the film was heat-treated at 120 ° C. for 10 minutes. A resin film (A6) having an antireflection layer (C2) having a thickness of 200 μm was obtained.

(Example 1) Production of polarizing plate for MVA On the film (A) side of the resin film (A3), a polyvinyl alcohol polymer (manufactured by Kuraray Co., Ltd .: PVA203, saponification degree 86.5-89.5%, average polymerization degree 300) ) Was added dropwise, and a polarizer made of an unstained PVA biaxially stretched film (polarized film manufactured by Nippon Synthetic Chemical Industry Co., Ltd .: Bobron # 140 (film thickness: 14 μm)) was bonded thereto. Next, the resin film (A1) was bonded to the other surface of the polarizer to obtain a polarizing plate. The evaluation results are shown in Tables 1 and 2.

Comparative Example 1 Production of MVA Polarizing Plate Resin film (A3) was changed to resin film (A6), and resin film (A1) adhered to the other surface of the polarizer was replaced with resin film (A4). A polarizing plate was obtained in the same manner as in Example 1 except for the change. The evaluation results are shown in Tables 1 and 2.

(Example 2) Production of polarizing plate for IPS A resin film comprising an alicyclic structure polymer resin (ZEONOR 1420, manufactured by Nippon Zeon Co., Ltd .; glass transition temperature Tg 136 ° C.) is formed into a longitudinal stretching machine (peripheral speed on the roll side). A method of uniaxially stretching in the longitudinal direction using the difference), stretching 1.3 times in an atmosphere of 140 ° C., average thickness 80 μm, in-plane (Re): 30 nm, thickness direction (Rth): A resin film (D1) having a retardation of 135 nm was obtained.

The film was cut into 50 cm ² and the die line was measured according to Evaluation (1). As a result, the maximum depth of the die line was 35 nm and the minimum width was 1500 nm.

  The thickness variation was 1.1%.

The water vapor transmission rate was 2.8 g / m ² · 24 hr.

  The resin film (A1) on the other surface of the polarizer was changed to a resin film (D1) while keeping the resin film (A3). Others were carried out similarly to Example 1, and obtained the polarizing plate. The evaluation results are shown in Tables 1 and 2.

(Comparative example 2) Production of polarizing plate for IPS Using the resin film (A4) produced in Production Example 2, using a longitudinal stretching machine (a method of uniaxially stretching in the longitudinal direction using the difference in peripheral speed on the roll side), The resin film (D2) having an average thickness of 78 μm, Re: 30 nm, and Rth: 135 nm was obtained by stretching 1.3 times in an atmosphere of 140 ° C.

The resin film (A4) was changed to the resin film (D2) while keeping the resin film (A6). Others were carried out similarly to the comparative example 1, and obtained the polarizing plate. The evaluation results are shown in Tables 1 and 2.

From the results in Table 1, the following can be understood.

  As shown in the examples, the polarizing plate of the present invention uses an alicyclic structure polymer resin and uses a resin film that is substantially free of die lines, thereby providing transparency, mechanical strength, antireflection performance, and scratch resistance. It can be seen that a polarizing plate having excellent adhesion can be formed.

  As shown in Table 2, when a liquid crystal display device was produced and the viewing angle was measured in accordance with various liquid crystal modes, it was found that the viewing angle characteristics of the retardation plate of the present invention were improved. Moreover, in the comparative example, the viewing angle was measured, but it was also confirmed that the brightness was lowered in addition to the viewing angle reduction as a whole.

It is a figure explaining the panel structure of a liquid crystal display device. It is a figure explaining the polarizing plate of this invention. It is a figure for demonstrating a die line.

Explanation of symbols

1 A resin film, a hard coat layer and an antireflection layer laminate.

2 Resin film.

3 Hard coat layer.
4 Antireflection layer.

5 It is a phase difference plate.

6 Polarizer.
7 Liquid crystal cell.

8 It is a phase difference plate.
9 Polarizer.

12-16 is a code | symbol explaining die line.

Claims (5)

On one side of the polarizer, it consists of an alicyclic structure-containing polymer resin,
The average thickness is 5 to 200 μm, the moisture permeability is 0.3 to 40 g / m ² · 24 hr, and the in-plane maximum value is 4 nm or less.
And the resin film (A), the hard coat layer (B) and the antireflection layer (C) having a maximum die line depth of 50 nm or less and a die line minimum width of 500 nm or more are sequentially laminated,
Polarized light formed by laminating a resin film (D) having an average thickness of 5 to 200 μm and a moisture permeability of 0.3 to 40 g / m ² · 24 h, on the other surface, made of an alicyclic structure-containing polymer resin. Board.   The polarizing plate according to claim 1, wherein the antireflective layer (C) has a refractive index of 1.36 or less.     The polarizing plate according to claim 1, wherein the antireflection layer (C) is a layer made of aerogel.     The polarizing plate according to claim 1, wherein the resin film (D) is a film showing retardation. The liquid crystal display device with which the polarizing plate in any one of Claims 1-4 is installed with the reflection prevention layer (C) side facing the visual recognition side.

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