KR20080055707A - Adhesive optical film and image display - Google Patents

Abstract

An adhesive optical film and an image display apparatus are provided to inhibit the non-uniformity of a peripheral portion in a display screen by using an acryl group polymer with the weight average molecular amount of 1-3 millions. An optical film has a discotic liquid layer(3) on a surface of a transparent base film(1). An adhesive layer(5) is formed on the discotic liquid layer. An alignment film(2) is formed between the transparent film and the discotic liquid layer. The surface of the transparent base film is also rubbed instead of the alignment film. A lower conduction layer(4) is interposed between the discotic liquid layer and the adhesive layer. A polarizer and a transparent protection film are stacked on the other surface of the transparent film. The transparent film also plays a role of the transparent protection film of the polarizer various transparent materials such as polyethyleneterephthalate or polyester group polymer or cellulose group polymer, acryl group polymer, styrene group polymer and polycarbonate group polymer are used to the transparent base film.

Description

Adhesive optical film and image display device {ADHESIVE OPTICAL FILM AND IMAGE DISPLAY}

The present invention relates to an adhesive optical film. Moreover, this invention relates to image display apparatuses, such as a liquid crystal display device, an organic electroluminescence display, a CRT, and a PDP using the said adhesive optical film.

The pressure-sensitive adhesive optical film of the present invention has a liquid crystal optical compensation layer, and is useful as an optical compensation film for improving the visual characteristics of the display contrast and the display color, and in particular, the laminated polarizer is provided with an optical compensation function. It is useful as an elliptical polarizing plate.

Liquid crystal displays are rapidly expanding in markets such as watches, mobile phones, PDAs, notebook PCs, PC monitors, DVD players, and TVs. The liquid crystal display device visualizes the change of the polarization state by switching of liquid crystal, and the polarizer is used from the display principle. In particular, high brightness and high contrast display are required for applications such as TVs, and brighter (high transmittance) and higher contrast (high polarization) light polarizers have been developed and introduced.

Currently, the mainstream system of the general liquid crystal display device is TFT-LCD using TN liquid crystal. This method has advantages such as fast response speed and high contrast. However, when the display of the panel using the TN liquid crystal is viewed at an angle inclined from its normal direction, the contrast is considerably lowered, and gray level inversion such that the gray scale display is reversed occurs, so that the TN liquid crystal has a very narrow viewing angle. Have On the other hand, in the use of a large PC monitor, a television, etc., high contrast, wide viewing angle, and a change in display color by viewing angle are few, etc. are calculated | required. Therefore, when the TFT-LCD of TN mode is used for such use, a retardation film for compensating the viewing angle is indispensable.

As this retardation film, the stretched birefringent polymer film has been used conventionally. In recent years, it has been proposed to use an optical compensation film having an optically anisotropic layer formed of liquid crystalline molecules on a transparent support instead of an optical compensation film made of a stretched birefringent film. Since the liquid crystal molecules have various alignment forms, the use of liquid crystal molecules makes it possible to realize optical properties that cannot be obtained in conventional stretched birefringent polymer films.

As the retardation film for viewing angle compensation as described above, for example, a wide view film manufactured by Fuji Photo Film Co., Ltd. using discotic liquid crystals having negative refractive index anisotropy is proposed (see Patent Document 1 and Patent Document 2). In this retardation film, one side of a transparent base film has a discotic liquid crystal layer in which the optical axis was diagonally aligned. In this retardation film, the objective is mainly to improve the viewing angle characteristic in the voltage application state of black display. That is, in the voltage application state, the liquid crystal molecules in a liquid crystal cell show positive refractive index anisotropy which has the optical axis inclined from the glass substrate. In order to compensate the phase difference by this refractive index anisotropy, the optical axis is inclined from the film normal direction and becomes the phase difference film using the liquid crystalline molecule which has negative refractive index anisotropy.

In the retardation film for viewing angle compensation, a polarizer is laminated on the transparent base film and used as an elliptically polarizing plate, while an adhesive layer is laminated on the discotic liquid crystal layer. A pressure-sensitive adhesive optical film such as a phase difference film or an elliptically polarizing plate in which the pressure-sensitive adhesive layer is laminated is attached to a liquid crystal cell or the like through the pressure-sensitive adhesive layer and used.

As an adhesive used for the said optical film with an adhesive, the acrylic adhesive which uses an acrylic polymer as a base polymer for the outstanding adhesiveness, transparency, etc. is used abundantly. Moreover, the crosslinking method of an acrylic adhesive uses many isocyanate type crosslinking agents, and mainly uses the bond with the functional monomer copolymerized to the acrylic polymer.

The liquid crystal panel which attached the said optical film to the liquid crystal cell is mounted in a liquid crystal display device, and is used. Liquid crystal display devices are used in calculators, watches, televisions, monitors, and the like. Since a liquid crystal display device is placed under various conditions, such as heating and humidification conditions, the high durability which does not impair the display quality is calculated | required also in such an environment.

However, when the liquid crystal display device is placed under heating or humidifying conditions, display irregularities may occur in the periphery of the liquid crystal panel, and display defects may occur. The display nonuniformity of this peripheral part was remarkably visible especially when the above-mentioned retardation film or elliptical polarizing plate for viewing angle compensation was used.

In order to improve the display nonuniformity of the said peripheral part, it is proposed to use the adhesive composition containing a plasticizer and an oligomer component as an adhesive used for the optical film provided with the adhesive (refer patent document 3, patent document 4). However, these adhesive compositions had a problem that additives, such as a plasticizer and an oligomer component, precipitate in a long time heating test, and an external appearance defect and an adhesive deteriorate.

Patent Document 1: Japanese Patent Application Laid-Open No. 8-95032

Patent Document 2: Japanese Patent No. 2767382

Patent Document 3: Japanese Patent Application Laid-Open No. 9-87593

Patent Document 4: Japanese Patent Application Laid-Open No. 10-279907

The present invention has a discotic liquid crystal layer in which a discotic liquid crystal compound is oriented on one side of the transparent base film, and furthermore, the discotic liquid crystal layer is durable as a pressure-sensitive adhesive optical film in which an adhesive layer is laminated. Moreover, it aims at providing the adhesive optical film which can suppress display nonuniformity in the peripheral part of a display screen.

Moreover, an object of this invention is to provide the image display apparatus using the said adhesive optical film.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the said subject, the present inventors discovered that the said objective could be achieved with the following adhesive optical film, and came to complete this invention.

That is, this invention is an adhesive optical film in which the adhesive layer is formed on the said discotic liquid crystal layer of the optical film which has a discotic liquid crystal layer on the single side | surface of a transparent base film,

The said adhesive layer contains the weight average molecular weight 1 million-3 million acrylic polymer containing a alkyl (meth) acrylate (a1) and (meth) acrylate (a2) which has a ring structure as a monomer unit, and a crosslinking agent. It relates to a pressure-sensitive adhesive optical film, characterized in that formed by the pressure-sensitive adhesive.

In the pressure-sensitive adhesive optical film, the acrylic polymer is a monomer unit,

30 to 90% by weight of alkyl (meth) acrylate (a1),

It is preferable to contain (meth) acrylate (a2) which has a ring structure in the ratio of 10-70 weight%.

In the said adhesive optical film, it is preferable that the (meth) acrylate (a2) which has a ring structure is (meth) acrylate which has an aromatic ring structure.

In the said adhesive optical film, an acryl-type polymer can contain monomer (a3) except the said (a1) component and (a2) component as a monomer unit further in the ratio of 10 weight% or less.

In the said adhesive optical film, it is preferable that an acrylic polymer is a weight average molecular weight 1 million-3 million, and the ratio of molecular weight 100,000 or less is 15 area% or less.

In the pressure-sensitive adhesive optical film, the pressure-sensitive adhesive preferably contains a silane coupling agent.

In the pressure-sensitive adhesive optical film, the pressure-sensitive adhesive layer is preferably formed on the discotic liquid crystal layer through the undercoat layer. The undercoating layer is preferably formed of a polyethyleneimine-based material.

In the pressure-sensitive adhesive optical film, a polarizer is laminated on one surface of the transparent base film on the side where the discotic liquid crystal layer is not formed as the optical film.

Moreover, this invention relates to the image display apparatus characterized by the said adhesive optical film being used.

Although the adhesive optical film of this invention has a discotic liquid crystal layer which functions as an optical compensation layer, it is an alkyl (meth) acrylate (a1) as a base polymer of the adhesive which forms the adhesive layer formed on the said discotic liquid crystal layer. ) And the display unevenness of the peripheral portion of the display screen can be suppressed by using an acrylic polymer having a weight average molecular weight of 1 to 3 million having a (meth) acrylate (a2) having a ring structure as the monomer component. Since the adhesive optical film of this invention suppresses the display nonuniformity of the peripheral part by using the said (a2) component as a monomer unit of the base polymer of the adhesive which forms an adhesive layer, In addition to a base polymer, a plasticizer etc. Like the pressure-sensitive adhesive using the additive of, the additive itself is not precipitated and the appearance defect and the pressure-sensitive adhesive are not deteriorated.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated, referring drawings. As shown in FIG. 1, the adhesive optical film of this invention has the discotic liquid crystal layer 3 on the single side | surface of the transparent base film 1, and the adhesive layer 5 is provided on the discotic liquid crystal layer 3 Formed. In FIG. 1, although the case where the alignment film 2 is formed between the transparent base film 1 and the discotic liquid crystal layer 3 is illustrated, instead of the alignment film 2, the single side | surface of the transparent base film 1 is rubbed-processed. You can use one.

Moreover, in FIG. 2, the adhesive optical film in which the adhesive layer 5 was formed on the discotic liquid crystal layer 3 through the undercoat 4 is illustrated.

3 is a polarizer 6 on one side of the transparent base film 1 on the side where the discotic liquid crystal layer 3 is not formed in the pressure-sensitive adhesive optical film of FIG. 2, followed by a transparent protective film 7. This is the case of using this laminated | stacked thing. In FIG. 3, the transparent base film 1 also serves as a transparent protective film of the polarizer 6. In addition, the aspect of FIG. 3 is similarly applicable also to the adhesive optical film of FIG.

As a transparent base film, various transparent materials can be used. For example, polyester polymers, such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers, such as diacetyl cellulose and triacetyl cellulose, acrylic polymers, such as polymethyl methacrylate, a polystyrene, an acrylonitrile styrene copolymer Styrene-type polymers, such as (AS resin), a polycarbonate polymer, etc. are mentioned. Polyolefin polymers such as polyethylene, polypropylene, cyclo- or norbornene structures, polyolefin-based polymers such as ethylene / propyl copolymers, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamides, imide-based polymers and liquors Phone polymer, polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, Epoxy-based polymers, blends of the polymers, and the like can also be cited as examples of the polymer forming the transparent base film.

Moreover, in the polymer film of Unexamined-Japanese-Patent No. 2001-343529 (WO01 / 37007), for example, the thermoplastic resin which has a substituted and / or unsubstituted imide group in (A) side chain, and (B) side chain And resin compositions containing a substituted and / or unsubstituted phenyl and a thermoplastic resin having a nitrile group. As a specific example, the film of the resin composition containing the alternating copolymer which consists of isobutylene and N-methyl maleimide, and an acrylonitrile styrene copolymer is mentioned. As a film, the film which consists of a mixed extrusion product of a resin composition, etc. can be used.

Although the thickness of a transparent base film can be suitably determined, in general, it is about 1-500 micrometers in terms of workability, thin-film property, etc., such as strength and handleability. In particular, 5-200 micrometers is preferable.

Moreover, it is preferable that a transparent base film does not have coloring as much as possible. Therefore, the phase difference in the film thickness direction expressed by Rth = (nx-nz) · d (where nx is the refractive index in the slow axis direction in the film plane, nz is the refractive index in the film thickness direction and d is the film thickness) is −90 nm. The protective film which is-+75 nm is used preferably. The coloring (optical coloring) of the polarizing plate resulting from a transparent base film can be almost eliminated by using what is the phase difference value (Rth) of -90 nm-+75 nm in the thickness direction. The thickness direction retardation Rth is more preferably -80 nm to +60 nm, particularly -70 nm to +45 nm.

As a transparent base film, cellulose polymers, such as triacetyl cellulose, and norbornene-type polymer are preferable from a viewpoint of polarization characteristic, durability, etc. In particular, cellulose polymers, such as triacetyl cellulose, are preferable.

The discotic liquid crystal layer is usually formed by the orientation and curing of a discotic liquid crystal compound having a polymerizable unsaturated group. The discotic liquid crystal layer is useful as an optical compensation layer and can improve the viewing angle, contrast, brightness, and the like. As for the discotic liquid crystal layer, it is preferable that the discotic liquid crystal compound is diagonally aligned. The thickness of a discotic liquid crystal layer is about 0.5-10 micrometers normally.

The discotic liquid crystal compound has negative refractive anisotropy (uniaxiality), for example, a benzene derivative described in C. Destrade et al., Mol. Crist. 71, p. 111 (1981); , B. Kohne et al., Angew. Chem. Vol. 96, page 70 (1984), cyclohexane derivatives and JMLehn et al., J. Chem. Comm., 1794 (1985), J. And the azacrown- or phenylacetylene-based macrocycles described in Zhang et al., J. Am. Chem. Soc. 116, page 2655 (1994). It is a structure which made into a mother core, the linear alkyl group, the alkoxy group, the substituted benzoyloxy group, etc. radially substituted as the linear chain, shows liquid crystallinity, and is generally called a discotic liquid crystal. However, as long as the molecule itself has negative uniaxiality and can provide a constant orientation, it is not limited to the above description. In addition, in the present invention, the discotic liquid crystal compound may be a polymerizable unsaturated group (eg, acryloyl group, methacryloyl group, vinyl group, allyl group, etc.) which is cured by heat, light, or the like. It is usually used to have. In addition, the discotic liquid crystal layer does not need to be the said compound finally made, The thing which superposed | polymerized or bridge | crosslinked by reaction of a polymerizable unsaturated group, and made into high molecular weight loses liquid crystal.

In addition, the discotic liquid crystal compound, such as a reaction product of a discotic liquid crystal which has not already exhibited liquid crystallinity by the reaction of various discotic liquid crystal compounds and other low molecular weight compounds and polymers, has its own optically negative uniaxiality. It means the compound having generally.

In the orientation treatment of the discotic liquid crystal, the surface of the transparent substrate film is subjected to a rubbing treatment or an alignment film is used. Examples of the alignment film include an inorganic film deposited film or an alignment film obtained by rubbing a specific organic polymer film. There is also a thin film in which isomerization is caused by light, such as an LB film made of an azobenzene derivative, and molecules are arranged uniformly with orientation. As an organic alignment film, the organic polymer film which forms hydrophobic surfaces, such as a polyimide film, alkyl chain modified system foaming, a polyvinyl butyral, and polymethyl methacrylate, is mentioned. In addition, a Si0 rectangular vapor deposition film is mentioned as an inorganic rectangular vapor deposition film.

As a means for diagonally aligning the discotic liquid crystal compound, for example, an alignment film is formed on a transparent base film, and then a discotic liquid crystal compound (polymerizable liquid crystal compound) is applied to be in an oblique alignment state. Or a method such as immobilization by light irradiation or heat such as purple external light can be used. Moreover, it can also form by carrying out the diagonal orientation of the discotic liquid crystal on another orientation base material, and transferring it using an optically transparent adhesive agent or a pressure sensitive adhesive agent on a transparent support body.

As such a discotic liquid crystal layer, the thing of patent document 1, 2 is used preferably. As a diagonal alignment layer of such discotic liquid crystal is formed on a cellulose-based polymer film, there is a wide view film manufactured by Fuji Photo Film.

It is preferable that the material which forms a undercoat layer shows favorable adhesiveness to any of an adhesive layer and a discotic liquid crystal layer, and forms the film excellent in cohesion force. In order to exhibit such a property, various polymers, sol of a metal oxide, a silica sol, etc. can be used. Among these, especially polymers are used preferably.

Examples of the polymers include polyurethane-based resins, polyester-based resins, and polymers containing amino groups in molecules. The use form of polymers may be any of solvent soluble type, water dispersion type and water soluble type. For example, water-soluble polyurethane, water-soluble polyester, water-soluble polyamide, etc., and water-dispersible resin (ethylene-vinyl acetate emulsion, (meth) acrylic emulsion, etc.) are mentioned. The water dispersion type is obtained by emulsifying various resins such as polyurethane, polyester, and polyamide using an emulsifier, and introducing an anionic group, a cationic group, or a nonionic group of a water dispersible hydrophilic group into a self-emulsifying agent in the resin. One can be used. Moreover, an ionic polymer complex can be used.

When these polymers contain an isocyanate type compound in an adhesive layer, for example, it is preferable to have a functional group which has reactivity with an isocyanate type compound. As said polymer, the polymer containing an amino group in a molecule | numerator is preferable. In particular, what has a primary amino group at the terminal is used preferably, and it adheres firmly by reaction with an isocyanate type compound.

Examples of the polymer containing an amino group in the molecule include polymers of amino group-containing monomers such as polyethyleneimine, polyallylamine, polyvinylamine, polyvinylpyridine, polyvinylpyrrolidine, and dimethylaminoethyl acrylate. Can be mentioned. Among these, polyethyleneimine type is preferable. The polyethyleneimine-based material may be one having a polyethyleneimine structure, and examples thereof include an ethyleneimine adduct and / or a polyethyleneimine adduct with respect to polyethyleneimine and polyacrylic acid ester.

Polyethylenimine is not specifically limited, Various things can be used. The weight average molecular weight of polyethyleneimine is not particularly limited, but is usually about 1 to 1 million. For example, examples of commercially available products of polyethyleneimine include Epomin SP series (SP-003, SP006, SP012, SP018, SP103, SP110, SP200, etc.) manufactured by Nippon Catalyst Co., Ltd., and Epomin P-1000. have. Among these, epomin P-1000 is preferable.

The polyacrylic acid ester of the ethyleneimine adduct and / or the polyethyleneimine adduct with respect to the polyacrylic acid ester is an alkyl (meth) acrylate constituting the base polymer (acrylic polymer) of the acrylic pressure sensitive adhesive described below and its copolymerization monomer in a conventional method. It can be obtained by emulsion polymerization accordingly. As a copolymerization monomer, in order to make ethylene imine etc. react, the monomer which has functional groups, such as a carboxyl group, is used. The use ratio of monomer which has functional groups, such as a carboxyl group, is suitably adjusted with the ratio of ethylene imine etc. made to react. Moreover, it is preferable to use a styrene-type monomer as a copolymerization monomer. Moreover, it can also be set as the adduct which grafted polyethyleneimine by making polyethyleneimine synthesize | combined separately react with the carboxyl group in acrylic ester etc. separately. For example, the polymer NK-380 by Nippon Catalysts Co., Ltd. is mentioned as an example of a commercial item.

Ethyleneimine adducts and / or polyethyleneimine adducts of acrylic polymer emulsions may also be used. For example, the polymer SK-1000 by Nippon Catalysts Co., Ltd. is mentioned as an example of a commercial item.

In addition, at the time of formation of an undercoat layer, in addition to the polymer containing an amino group, the compound reacting with the polymer containing an amino group can be mixed and bridge | crosslinked, and the strength of a undercoat layer can be improved. Epoxy compounds etc. can be illustrated as a compound reacting with the polymer containing an amino group.

When forming a undercoat layer, after forming a undercoat layer on the said optical film, an adhesive layer is formed. For example, the undercoat solution like the polyethyleneimine aqueous solution is apply | coated and dried using coating methods, such as a coating method, the dipping method, and a spray method, and a undercoat layer is formed. The thickness of the undercoat layer is preferably in the range of about 10 to 5000 nm and in the range of 50 to 500 nm. When the thickness of the undercoat layer becomes thin, it does not have the property as a bulk, it does not show sufficient strength, and sufficient adhesiveness may not be obtained. Moreover, when too thick, there exists a possibility of causing the fall of an optical characteristic.

The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer of the present invention contains an acrylic polymer containing, as a base polymer, an alkyl (meth) acrylate (a1) and a (meth) acrylate (a2) having a ring structure as a monomer unit. . In addition, (meth) acrylate refers to acrylate and / or methacrylate, and has the same meaning as (meth) of this invention.

Carbon number of the alkyl group of alkyl (meth) acrylate (a1) is about 1-18, Preferably it is C1-C9, and an alkyl group may be any of a linear and branched chain. As a specific example of alkyl (meth) acrylate, For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth ) Acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) Acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, etc. are mentioned. These may be used alone or in combination. It is preferable that the average carbon number of these alkyl groups is 4-12.

As a ring structure of the (meth) acrylate (a2) which has a ring structure, an aromatic ring structure and an alicyclic structure are mentioned. Examples of the aromatic ring structure include a benzene ring, naphthalene ring, thiophene ring, pyridine ring, pyrrole ring and furan ring. Examples of the (meth) acrylate having an aromatic ring structure include phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, phenoxy-2-hydroxypropyl (meth) acrylate, and phenol ethylene oxide. Modified (meth) acrylate, 2-naphthoxyethyl (meth) acrylate, 2- (4-methoxy-1-naphthoxy) ethyl (meth) acrylate, phenoxypropyl (meth) acrylate, phenoxy ethylene Glycol (meth) acrylate, thiophenyl (meth) acrylate, pyridyl (meth) acrylate, pyrrolyl (meth) acrylate, phenyl (meth) acrylate, polystyryl (meth) acrylate, and the like. . On the other hand, as an alicyclic structure, a cyclo ring, a terpene ring, a bicyclo ring, a tetrahydrofuran ring, a piperidine ring, a pyrrolidine ring, a morpholine ring, etc. are mentioned. As a (meth) acrylate which has an alicyclic structure, for example, cyclohexyl (meth) acrylate, isobonylkishi (meth) acrylate, cyclopentyl (meth) acrylate, dicyclopentenyl (meth) acrylate , Dicyclopentenyloxyethyl (meth) acrylate, tricyclo [5.2.1.0 ^2,6 ] decanyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, acryloyl morpholine, and the like. have. As (meth) acrylate (a2) which has a ring structure, the (meth) acrylate which has an aromatic ring structure is preferable at the point which reduces the display nonuniformity of a peripheral part. Although this reason is not clear, it is thought that one of the reasons is that the polarization rate of an aromatic ring is high. In particular, the (meth) acrylate having a phenyl group such as phenoxyethyl (meth) acrylate and phenoxy-2-hydroxypropyl (meth) acrylate is more widely used because a benzene ring and an ether bond are connected. It is preferable because this becomes high.

In the acrylic polymer, the ratio of the alkyl (meth) acrylate (a1) and the (meth) acrylate (a2) having a ring structure is 30 to 90% by weight of the alkyl (meth) acrylate (a1) as a monomer unit. It is preferable to use (meth) acrylate (a2) which has a ring structure in 10 to 70weight% of a range. Moreover, it is more preferable that it is 15-60 weight%, and, as for the (meth) arcrelate (a2) which has a ring structure, it is more preferable that it is 20-50 weight%. In addition, an alkyl (meth) acrylate (a1) becomes a remainder of the said (a2) component normally. It is preferable to make the ratio of the said (a2) component 10 weight% or more from the point which can reduce peripheral unevenness, and by making it 70 weight% or less, peripheral unevenness and durability can be improved.

Moreover, an acryl-type polymer can contain a monomer (a3) component except the said (a1) component and (a2) component further as a monomer unit.

As said (a3) component, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxy hexyl, for example (Meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate or (4-hydroxymethylcyclohexyl)- Hydroxyl group-containing monomers such as methyl acrylate; Carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid; Acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; Caprolactone adducts of acrylic acid; Sulfonic acid group-containing monomers such as allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamide propanesulfonic acid, and sulfopropyl (meth) acrylate; Phosphoric acid group containing monomers, such as 2-hydroxyethyl acryloyl phosphate, etc. are mentioned.

Moreover, a nitrogen containing vinyl monomer is mentioned as said (a3) component. For example, maleimide; (Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methyl (meth) acrylamide, N- (N-substituted) amide monomers such as butyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, and N-methylolpropane (meth) acrylamide; Alkylaminoalkyl (meth) acrylates, such as aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, N, N- dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate Monomers; Alkoxy alkyl (meth) acrylate type monomers, such as methoxy ethyl (meth) acrylate and ethoxy ethyl (meth) acrylate; Such as N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, and N- (meth) acryloyl-8-oxyoctamethylene succinimide Succinimide type monomers etc. are also mentioned as an example of a monomer for modification.

Moreover, as said (a3) component, Vinyl-type monomers, such as vinyl acetate, a vinyl propionate, N-vinyl carboxylic acid amides, styrene, (alpha) -methylstyrene, and N-vinyl caprolactam; Nitrile monomers such as acrylonitrile and methacrylonitrile; Epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; Glycol-based acrylic ester monomers such as polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, and methoxy polypropylene glycol (meth) acrylate; (Meth) acrylate type monomers, such as fluorine (meth) acrylate, silicone (meth) acrylate, and 2-methoxyethyl acrylate, can also be used.

The said (a3) component can be used arbitrarily in order to modify a base polymer. The said (a3) component can use 1 type (s) or 2 or more types. It is preferable to make the ratio of the said (a3) component into 10 weight% or less and 6 weight% or less as a monomeric unit in an acryl-type polymer. When the ratio of the said (a3) component exceeds 10 weight%, it is unpreferable in the point which may impair the flexibility as an adhesive.

As said (a3) component, since the adhesiveness is favorable, the monomer containing a carboxyl group, especially acrylic acid is used preferably. When using the monomer containing a carboxyl group, the ratio is about 0.1-10 weight%, Preferably it is 0.5-8 weight%, More preferably, it is 1-6 weight%. Moreover, a hydroxyl group containing monomer is used preferably at the point which can become a crosslinking point with an isocyanate crosslinking agent. When using a hydroxyl group containing monomer, the ratio is about 0.1-10 weight%, Preferably it is 0.5-8 weight%, More preferably, it is 1-6 weight%.

Manufacture of the said acrylic polymer can be manufactured by various well-known methods, For example, radical polymerization methods, such as a bulk polymerization method, a solution polymerization method, and suspension polymerization method, can be selected suitably. As a radical polymerization initiator, various well-known thing of azo type and a peroxide type can be used. Reaction temperature is about 50-80 degreeC normally, and reaction time is 1 to 8 hours. Moreover, the solution polymerization method is preferable also in the said manufacturing method, and ethyl acetate, toluene, etc. are generally used as a solvent of an acryl-type polymer. The solution concentration is usually about 20 to 80% by weight. Moreover, an acryl-type polymer can be obtained as an aqueous emulsion.

The weight average molecular weights of an acryl-type polymer are 1 million-3 million. It is preferable that it is more than 2 million-3 million, and, as for the weight average molecular weight of an acryl-type polymer, 1 million-2 million is preferable. If the weight average molecular weight is less than 1 million, peripheral irregularities and durability cannot be satisfied. On the other hand, when the weight average molecular weight exceeds 3 million, it is unpreferable from a viewpoint of reducing adhesiveness. Moreover, it is preferable that the ratio of the low molecular weight of 100,000 or less molecular weight of an acrylic polymer is 15 area% or less. By making the ratio of the said low molecular weight small, peripheral part nonuniformity can be suppressed more. It is preferable that the ratio of the said low molecular weight is 10 area% or less, Furthermore, it is preferable that it is 5 area% or less. Moreover, in order to make the ratio of low molecular weight small, it can achieve by controlling the density | concentration at the time of superposing | polymerizing a polymer, an initiator type, the quantity, and polymerization temperature. It is better to make monomer concentration high and to make polymerization temperature low. Specifically, when an azobisisobutyronitrile or benzoyl peroxide is used as an initiator, it can achieve by making it react for about 8 hours at 50-60 degreeC of polymerization temperatures. If the polymerization temperature is too low, the polymerization reaction is not initiated. If the polymerization temperature is too high, the low molecular weight component is increased to deteriorate the peripheral unevenness. In addition, even if the initiator is reintroduced in the middle of polymerization, the low molecular weight component is increased and the peripheral irregularity is worsened.

The weight average molecular weight of the acrylic polymer was measured under the following conditions of the GPC (gel permeation chromatography) side.

Analytical device: manufactured by Tosoh, HLC-8120 GPC.

Column: Tosoh, G7000HXL + GMHXL + GMHXL.

Column size: Each 7.8 mm diameter x 30 cm total 90 cm.

Column temperature: 40 ° C.

Flow rate: 0.8 ml / min.

Injection volume: 100 μl.

Eluent: tetrahydrofuran.

Detector: Preview Refractometer.

Standard sample: polystyrene.

Ratio of molecular weight 100,000 or less: From the result of GPC measurement, the weight fraction (area%) was computed by the data processing apparatus (Toso make, GPC-8020). At this time, the monomer component was not included.

The adhesive which forms the adhesive layer of this invention contains a crosslinking agent in addition to the said acrylic polymer which is a base polymer. By a crosslinking agent, adhesiveness and durability with an optical film can be improved, and reliability at high temperature and maintenance of the shape of the adhesive itself can be aimed at. As a crosslinking agent, an isocyanate type, an epoxy type, a peroxide type, a metal chelate type, an oxazoline type, etc. can be used suitably. These crosslinking agents can be used 1 type or in combination of 2 or more type. As a crosslinking agent, the crosslinking agent containing the hydroxyl group and the functional group which exhibits reactivity is preferable, and an isocyanate type crosslinking agent is especially preferable.

An isocyanate compound is used for an isocyanate type crosslinking agent. As an isocyanate compound, tolylene diisocyanate, chlorphenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate Isocyanate monomers such as isocyanate monomers such as trimethylolpropane and the like; Isocyanurate, a biuret type compound, Furthermore, the urethane prepolymer type isocyanate etc. which added-reacted well-known polyether polyol, polyester polyol, acryl polyol, polybutadiene polyol, polyisoprene polyol, etc. are mentioned.

As an epoxy type crosslinking agent, the bisphenol A epichlorohydrin type epoxy resin is mentioned, for example. Moreover, as an epoxy type crosslinking agent, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycid Dilether, trimethylolpropanetriglycidylether, diglycidylaniline, N, N, N ', N'-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N-diglyl) Cydylaminomethyl) cyclohexane, N, N, N ', N'-tetraglycidylaminophenylmethane, triglycidyl isocyanurate, mN, N- diglycidylaminophenyl glycidyl ether, N , N-diglycidyl toluidine, N, N-diglycidyl aniline, and the like.

As the peroxide crosslinking agent, various peroxides are used. As the peroxide, di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxy neodecanoate, t- Hexyl peroxy pivalate, t-butyl peroxy pivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxyisobutylate, 1,1 , 3,3-tetramethylbutylperoxy2-ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoylperoxide, t-butylperoxyisobutyrate and the like. Among these, di (4-t-butylcyclohexyl) peroxydicarbonate, dilauroyl peroxide, and dibenzoyl peroxide, which are particularly excellent in crosslinking reaction efficiency, are preferably used.

The usage-amount of a crosslinking agent is 10 weight part or less with respect to 100 weight part of acrylic polymers (A), Preferably it is 0.01-5 weight part, More preferably, it is 0.02-3 weight part. When the use ratio of a crosslinking agent exceeds 10 weight part, since crosslinking advances too much and adhesiveness may fall, it is unpreferable.

Furthermore, in the optical adhesive of this invention, the filler, pigment, colorant, filler, antioxidant, ultraviolet absorber which consists of a tackifier, a plasticizer, glass fiber, glass beads, metal powder, other inorganic powder etc. as needed is needed. And a silane coupling agent and the like, and various additives may be suitably used within a range not departing from the object of the present invention. Moreover, it is good also as an adhesive layer etc. which contain microparticles | fine-particles and show light diffusivity.

As said additive, a silane coupling agent is preferable. As a silane coupling agent, it has epoxy structures, such as 3-glycidoxy propyl trimethoxysilane, 3-glycidoxy propylmethyldimethoxysilane, and 2- (3, 4- epoxycyclohexyl) ethyltrimethoxysilane. Silane coupling agent; 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl- Amino group-containing silane coupling agents such as N- (1,3-dimethylbutylidene) propylamine; (Meth) acryl-group containing silane coupling agents, such as 3-acryloxypropyl trimethoxysilane and 3-methacryloxypropyl triethoxysilane; Isocyanate group containing silane coupling agents, such as 3-isocyanate propyl triethoxysilane; 3-chloropropyltrimethoxysilane; Acetacetyl group containing trimethoxysilane etc. are mentioned. Although a silane coupling agent may be used individually by 1 type, and may mix and use 2 or more types, The compounding quantity of a silane coupling agent is 0.01-2 weight part with respect to 100 weight part of acrylic polymers, Preferably it is 0.02 It is -1 weight part.

The adhesive optical film of this invention forms the adhesive layer by the said adhesive on the said discotic liquid crystal layer formed on the said transparent base film. Moreover, when it has a undercoat layer on the said discotic liquid crystal layer, an adhesive layer is formed in the undercoat layer.

The formation method of an adhesive layer is not specifically limited, The method of apply | coating and drying an adhesive solution on the said discotic liquid crystal layer (or undercoat layer) by appropriate development methods, such as a casting method and a coating system, and the release sheet which formed the adhesive layer. And a method of transferring by the same. As the coating method, a roll coating method such as reverse coating or gravure coating, a spin coating method, a screen coating method, a fountain coating method, a dipping method, a spray method, or the like can be adopted. After apply | coating an adhesive solution, the adhesive layer of predetermined thickness is obtained by volatilizing a solvent and water in a drying process.

The thickness of an adhesive layer can be suitably determined according to a use purpose, adhesive force, etc., and is generally 1-500 micrometers, Preferably it is 1-50 micrometers. Furthermore, 1-40 micrometers is preferable, Furthermore, 5-30 micrometers is preferable, and 10-25 micrometers is especially preferable. When it is thinner than 1 µm, durability deteriorates, and when thicker, moxibustion or peeling due to foaming or the like tends to occur, and appearance tends to be poor.

Moreover, formation of an adhesive layer can apply | coat UV curable adhesive syrup on a release film, and can form the adhesive layer containing the said acrylic polymer by irradiating radiation, such as an electron beam or UV. At this time, since the crosslinking agent is contained in the adhesive, the reliability at high temperature and the shape of the adhesive itself can be achieved.

In addition, the crosslinking of an adhesive layer can be performed at the said drying process and a UV irradiation process, and also can also select the crosslinking form which crosslinking promotes by aging by a warm state or room temperature standing after drying.

As the constituent material of the release sheet, suitable thin films such as synthetic resin films such as paper, polyethylene, polypropylene, polyethylene terephthalate, rubber sheets, paper, textiles, nonwoven fabrics, nets, foam sheets, metal foils, and laminates thereof may be used. Can be mentioned. In order to improve the peelability from an adhesive layer, the surface of a release sheet may be given low adhesive peeling processes, such as a silicone treatment, a long chain alkyl treatment, and a fluorine treatment, as needed.

Moreover, in each layer, such as an optical film and an adhesive layer of the adhesive optical film of this invention, a salicylic acid ester type compound, a benzophenol type compound, a benzotriazole type compound, a cyanoacrylate type compound, and a nickel complex salt type system are mentioned, for example. The thing which gave ultraviolet absorption ability by methods, such as a process with a ultraviolet absorber, such as a compound, may be sufficient.

An antistatic agent can also be used for an adhesive optical film in order to provide antistatic property. An antistatic agent can be contained in each layer, and can also form an antistatic layer separately. As an antistatic agent, Ionic surfactant type; Conductive polymers such as polyaniline, polythiophene, polypyrrole, and polyquinoxaline; Although metal oxide systems, such as tin oxide, antimony oxide, and indium oxide, etc. are mentioned, Especially a conductive polymer type is preferable from a viewpoint of the stability at the time of heat, humidification of an optical characteristic, an external appearance, an antistatic effect, and an antistatic effect. Used. Among these, water-soluble conductive polymers such as polyaniline and polythiophene or water-dispersible conductive polymers are particularly preferably used. This is preferable from the viewpoint of suppressing the deterioration of the optical film base material by the organic solvent at the time of the application step when a water-soluble conductive polymer or a water dispersible conductive polymer is used as the material for forming the antistatic layer.

As shown in FIG. 3, the optical film of the present invention has a polarizer 6 on one side of the transparent base film 1 on the side where the discotic liquid crystal layer 3 is not formed, followed by a transparent protective film 7. This laminated thing can be used.

The polarizer 6 can be attached to the transparent base film 1 using an adhesive agent. In addition, in FIG.2, FIG.3, although the transparent base film 1 serves as the transparent protective film of the polarizer 6, the transparent base film 1 has the polarizing plate which has a transparent protective film in the one or both surfaces of a polarizer. It can also be laminated.

A polarizer is not specifically limited, Various things can be used. As a polarizer, the dichroic substance of iodine or a dichroic dye is adsorb | sucked to hydrophilic polymer films, such as a polyvinyl alcohol-type film, a partially formalized polyvinyl alcohol-type film, and an ethylene vinyl acetate copolymerization partial saponification film, for example. The polyene type orientation film, such as the thing uniaxially stretched, the dehydration process of polyvinyl alcohol, and the dehydrochlorination process of polyvinyl chloride, etc. are mentioned. Among these, the polarizer which consists of dichroic substances, such as a polyvinyl alcohol-type film and iodine, is preferable. Although the thickness in particular of these polarizers is not restrict | limited, Usually, it is about 5-80 micrometers.

The polarizer which dyed a polyvinyl alcohol-type film with iodine and uniaxially stretched can be manufactured, for example, by dyeing polyvinyl alcohol in the aqueous solution of iodine, and extending | stretching 3-7 times the original length. It can also be immersed in aqueous solution, such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride, etc. as needed. If necessary, the polyvinyl alcohol-based film may be dipped in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, the contamination of the polyvinyl alcohol-based film with the antiblocking agent can be washed, and the polyvinyl alcohol-based film is swelled to prevent irregularities such as staining. Stretching may be performed after dyeing with iodine, or may be performed while dyeing, or may be dyed with iodine after stretching. It can extend | stretch also in aqueous solution, such as boric acid and potassium iodide, or a water bath.

As a material which forms the transparent protective film formed on the single side | surface or both surfaces of the said polarizer, it is preferable that it is excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, etc. The material similar to a transparent base film can be used for a transparent protective film. The same applies to the thickness.

In addition, the same polymer material may be used for a transparent base film and a transparent protective film, and a different polymer material etc. may be used.

The polarizer, the transparent base film and the transparent protective film are usually in close contact with each other through an aqueous adhesive or the like. As an aqueous adhesive agent, an isocyanate adhesive, a polyvinyl alcohol adhesive, a gelatin adhesive, a vinyl latex type, an aqueous polyurethane, an aqueous polyester, etc. can be illustrated. In addition, at the time of attachment of a polarizer, a transparent base film, and a transparent protective film, an activation process can be performed to a transparent base film and a transparent protective film. Various methods can be adopted for the activation treatment, and for example, saponification treatment, corona treatment, low pressure UV treatment, plasma treatment and the like can be adopted. The activating treatment is particularly effective in the case of a triacetyl cellulose, norbornene-based resin, polycarbonate, polyolefin resin or the like.

The surface which does not adhere | attach the polarizer of the said transparent protective film may be the thing which performed the process for the purpose of a hard-coat layer, an antireflection process, sticking prevention, and diffused or antiglare.

The hard coat treatment is carried out for the purpose of preventing scratches on the surface of the polarizing plate, and the like, for example, adding a cured film having excellent hardness and slipping properties by suitable ultraviolet curable resins such as acrylic and silicon to the surface of the transparent protective film. It can form in a manner etc. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the prior art. In addition, sticking prevention processing is performed for the purpose of preventing adhesion with the adjacent layer of another member.

The antiglare treatment is performed for the purpose of preventing external light from being reflected on the surface of the polarizing plate and impairing the visibility of the polarizing plate transmitted light. For example, the roughening method and the transparent fine particle of the sandblasting method or the embossing method are used. It can form by providing a fine concavo-convex structure to the surface of a transparent protective film by a suitable method, such as a compounding system. Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include a conductive material composed of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, or the like having an average particle diameter of 0.5 to 50 µm. Transparent fine particles such as inorganic fine particles, organic fine particles (including beads) made of a crosslinked or uncrosslinked polymer, and the like are used. When forming a surface fine uneven structure, the usage-amount of microparticles | fine-particles is about 2-50 weight part generally with respect to 100 weight part of transparent resin which forms a surface fine uneven structure, and 5-25 weight part is preferable. The antiglare layer may also serve as a diffusion layer (visual magnification function, etc.) for diffusing the polarizing plate transmitted light to enlarge the time and the like.

The antireflection layer, the sticking prevention layer, the diffusion layer, the antiglare layer, and the like can be formed on the transparent protective film itself, and can be formed separately from the transparent protective film as an optical layer.

Moreover, in addition to the optical film which laminated | stacked the said polarizing plate, as an optical film used for the adhesive optical film of this invention, it is used for formation of image display apparatuses, such as a liquid crystal display device, and an optical layer can be laminated | stacked. For example, the optical layer which may be used for formation of liquid crystal display devices, such as a reflecting plate, a semi-transmissive plate, a retardation plate (including wavelength plates, such as 1/2 or 1/4), a brightness enhancement film, etc. Can be mentioned. These can be used independently as an optical film, can be laminated | stacked on the said polarizing plate at the time of practical use, and can use 1 layer or 2 or more layers.

In particular, a reflective polarizing plate or semi-transmissive polarizing plate in which a reflecting plate or a semi-transmissive reflecting plate is further laminated on the polarizing plate, an elliptical polarizing plate or circular polarizing plate in which a retardation plate is further laminated on the polarizing plate, or a brightness enhancing film is further laminated on the polarizing plate Polarizing plates are preferred.

The reflective polarizer is formed by forming a reflective layer on the polarizer, and is used to form a liquid crystal display device of a type that reflects and displays incident light from the visual recognition side (display side), and can incorporate a light source such as a backlight. This has advantages such as easy thinning of the liquid crystal display device. Formation of a reflective polarizing plate can be performed by a suitable method, such as the method of laying a reflective layer which consists of metal etc. on the single side | surface of a polarizing plate through a transparent protective layer etc. as needed.

As a specific example of a reflective polarizing plate, what provided the reflective layer by laying the foil and vapor deposition film which consist of reflective metals, such as aluminum, on the single side | surface of the transparent protective film which carried out the mat process as needed. Moreover, what contains microparticles | fine-particles in the said transparent protective film to make surface fine concavo-convex structure, and has a reflective layer of a fine concavo-convex structure on it, etc. are mentioned. The above-described reflective layer of the fine concavo-convex structure has the advantage of being able to diffuse the incident light by diffuse reflection to prevent directivity and shiny gloss, and to suppress unevenness of light and dark. Moreover, the protective film containing microparticles | fine-particles has the advantage etc. which diffuse when an incident light and its reflection light permeate | transmit it, and can suppress a light and shade nonuniformity more. The formation of the reflective layer of the finely uneven structure reflecting the surface finely uneven structure of the transparent protective film is, for example, by directly depositing a metal directly on the surface of the transparent protective layer in an appropriate manner such as vacuum deposition, ion plating, sputtering or plating. We can carry out by method of laying

Instead of the method of directly applying to the transparent protective film of the polarizing plate, the reflecting plate may be used as a reflecting sheet formed by forming a reflecting layer on a suitable film according to the transparent film. In addition, since the reflective layer is usually made of a metal, the use mode in which the reflective surface is covered with a transparent protective film, a polarizing plate, or the like prevents the reduction of the reflectance due to oxidation, and furthermore, the surface of the long-term sustaining of the initial reflectance or the protection. It is preferable from the standpoint of avoiding separate laying of layers.

In addition, a semi-transmissive polarizing plate can be obtained by reflecting light in a reflection layer in the above, and making it into a semi-transmissive reflection layer, such as a translucent mirror which permeate | transmits. The transflective polarizing plate is usually formed on the back side of the liquid crystal cell, and when using a liquid crystal display device or the like in a relatively bright atmosphere, reflects incident light from the viewing side (display side) to display an image, and is relatively dark. In the atmosphere, a liquid crystal display device of a type for displaying an image or the like can be formed using a built-in power supply such as a backlight built in the back side of the transflective polarizing plate. That is, the transflective polarizing plate can save energy of using a light source such as a backlight in a bright atmosphere, and is useful for forming a liquid crystal display device of the type that can be used using a built-in power supply even in a relatively dark atmosphere.

An elliptical polarizing plate or circularly polarized light in which a retardation plate is further laminated on the polarizing plate will be described. In the case of changing linearly polarized light into elliptical polarization or circularly polarized light, or changing elliptical or circularly polarized light into linearly polarized light or changing the polarization direction of linearly polarized light, a retardation plate or the like is used. In particular, a so-called quarter wave plate (also referred to as λ / 4 plate) is used as the phase difference plate which changes linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light. The half wave plate (also called a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

An elliptical polarizing plate is effectively used for compensating (preventing) coloration (blue or yellow) caused by birefringence of a liquid crystal layer of a super twist nematic (STN) type liquid crystal display device, and for displaying monochrome display without the coloration. Moreover, it is preferable to control the three-dimensional refractive index because the coloring degree which arises when the screen of a liquid crystal display device is seen from the inclination direction can be compensated (prevented). The circular polarizing plate is effectively used when the color tone of an image of a reflection type liquid crystal display device in which an image becomes color display is, for example, and also has a function of antireflection.

As a retardation plate, the birefringent film formed by carrying out uniaxial or biaxial stretching process of a polymeric material, the orientation film of a liquid crystal polymer, the thing which supported the orientation layer of a liquid crystal polymer with a film, etc. are mentioned. Although the thickness of a retardation plate is not specifically limited, either, about 20-150 micrometers is common.

Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, and polyarylate. , Polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyphenylene sulfide, polyphenylene oxide, polyallyl sulfone, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose polymer, norbornene-based resin Or these binary or ternary various copolymers, graft copolymers, blends and the like. These polymer raw materials become an orientation substance (stretched film) by extending | stretching etc.

As a liquid crystal polymer, the main chain type and side chain type various things etc. which the conjugated linear atomic group (mesogen) which gives liquid crystal aligning property were introduce | transduced into the main chain and side chain of a polymer are mentioned, for example. Specific examples of the main chain type liquid crystal polymer include, for example, a nematic oriented polyester liquid crystal polymer, a discotic polymer or a cholesteric polymer having a structure in which a mesogenic group is bonded to a spacer portion providing flexibility. Can be. Specific examples of the side chain type liquid crystal polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a parasitic nematic parasitic agent through a spacer portion composed of a conjugated atomic group as a side chain. The thing which has the mesogenic part which consists of substituted cyclic compound units, etc. are mentioned. These liquid crystal polymers, for example, the rubbing treatment of the surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, and the liquid crystal polymer on the alignment treatment surface such as silicon oxide deposited on all sides It is performed by developing and heat-processing a solution.

The retardation plate may have an appropriate retardation according to the purpose of use, for example, for the purpose of compensating coloring or vision due to birefringence of various wavelength plates and liquid crystal layers, or by laminating two or more kinds of retardation plates. The thing which controlled optical characteristics, such as a phase difference, may be sufficient.

Moreover, said elliptical polarizing plate and reflective elliptic polarizing plate laminate | stack a polarizing plate or a reflective polarizing plate, and a phase difference plate by a suitable combination. Such elliptical polarizing plates and the like can be formed by sequentially stacking them separately in the manufacturing process of the liquid crystal display device so as to be a combination of the (reflective) polarizing plate and the retardation plate. It is excellent in stability of quality, lamination workability, etc., and there exists an advantage which can improve manufacturing efficiency, such as a liquid crystal display device.

The polarizing plate which affixed the polarizing plate and a brightness improving film is normally formed in the back side of a liquid crystal cell, and is used. The brightness enhancement film exhibits a property of reflecting linearly polarized light on a predetermined polarization axis or circularly polarized light in a predetermined direction when natural light is incident by a backlight such as a liquid crystal display device or reflection from the back side, and transmitting other light. The polarizing plate laminated | stacked with the polarizing plate injects light from light sources, such as a backlight, and acquires the transmitted light of a predetermined polarization state, and reflects the light other than the said predetermined polarization state without transmitting. The light reflected from the surface of the brightness enhancing film is inverted again through a reflective layer or the like formed on the back side thereof, and re-entered into the brightness enhancing film, and a part or all of the light is transmitted as light in a predetermined polarization state to transmit light of the brightness improving film. The brightness can be improved by increasing the amount of light and supplying the polarized light which is hardly absorbed by the polarizer and increasing the amount of light that can be used for liquid crystal display image display and the like. That is, when light is incident from the back side of the liquid crystal cell through a backlight or the like without using the brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is absorbed by the polarizer and the polarizer It does not penetrate. That is, although it changes also with the characteristic of the polarizer used, about 50% of light is absorbed by a polarizer, and the amount of light which can be used for a liquid crystal image display etc. by that amount reduces and an image becomes dark. The brightness enhancement film generally reflects light having a polarization direction absorbed by the polarizer into the brightness enhancement film without incident on the polarizer, and is inverted again through a reflective layer or the like provided on the back side thereof, and reenters the brightness enhancement film. It is repeated, and only the polarization direction in which the polarization direction of the light reflected and inverted between the two becomes the polarization direction through which the polarizer can pass can be transmitted to the polarizer, so that light such as a backlight can be efficiently provided. It can be used to display an image of a display device, and the screen can be brightened.

A diffusion plate may be formed between the brightness enhancing film and the reflective layer. The light in the polarization state reflected by the brightness enhancement film is directed toward the reflective layer or the like. The diffuser plate uniformly diffuses the light passing therethrough and at the same time eliminates the polarization state, thereby becoming a non-polarization state. That is, the light in a natural light state is reflected toward a reflection layer, etc., is reflected through a reflection layer, etc., and passes again through a diffuser plate, and re-injects into a brightness improving film is repeated. Thus, by forming a diffuser plate which returns the polarization to the original natural light between the brightness enhancing film and the reflective layer, the brightness of the display screen is maintained while the brightness unevenness of the display screen is reduced, thereby providing a uniform and bright screen. can do. By forming such a diffuser plate, it is considered that the first incident light can be appropriately increased in the number of repetitions of reflection, thereby providing a uniform bright display screen with the diffuser function of the diffuser plate.

As said brightness improving film, the cholesteric which shows the characteristic which permeate | transmits linearly polarized light of a predetermined polarization axis and reflects other light, such as the multilayered thin film of a dielectric material and the multilayer laminated body of a thin film film from which refractive index anisotropy differs, is cholesteric As supporting the alignment film of the liquid crystal polymer and the alignment liquid crystal layer on the film substrate, suitable ones such as those exhibiting the characteristics of reflecting either circularly polarized light of left rotation or right rotation and transmitting other light can be used.

Therefore, in the luminance improvement film of the type which permeate | transmits linearly polarized light of the predetermined polarization axis mentioned above, it can transmit efficiently, restraining the absorption loss by a polarizing plate by making the transmitted light into a polarizing plate as it enters. On the other hand, in the luminance improvement film of the type which transmits circularly polarized light like a cholesteric liquid crystal layer, although it may be made to enter into a polarizer as it is, in view of suppressing absorption loss, the circularly polarized light is linearly polarized through a phase difference plate, It is preferable to make it incident on a polarizing plate. In addition, circular polarization can be converted into linearly polarized light by using a quarter wave plate as the retardation plate.

A retardation plate which functions as a quarter wave plate at a wide wavelength such as visible range is, for example, a phase difference layer exhibiting retardation characteristics different from that of a retardation plate functioning as a quarter wave plate for light having a wavelength of 550 nm. For example, it can obtain by the method of superimposing the retardation layer which functions as a 1/2 wave plate. Therefore, the phase difference plate arrange | positioned between a polarizing plate and a brightness enhancement film may consist of one layer or two or more phase difference layers.

In addition, also in the cholesteric liquid crystal layer, by combining the two or three or more layers with a combination of different reflection wavelengths, it is possible to obtain the reflection of circularly polarized light in a wide wavelength range such as visible light. Based on this, transmission circularly polarized light in a wide wavelength range can be obtained.

Moreover, the polarizing plate may consist of what laminated | stacked the polarizing plate and two or three or more optical layers like the said polarization split type polarizing plate. Therefore, the reflective elliptically polarizing plate, the semi-transmissive elliptically polarizing plate, etc. which combined said reflective polarizing plate, semi-transmissive polarizing plate, and retardation plate may be sufficient.

Although the optical film which laminated | stacked the said optical layer on the polarizing plate can also be formed also in the method of sequentially laminating | stacking separately in manufacturing processes, such as a liquid crystal display device, what laminated | stacked previously and made into the optical film is that stability of quality, an assembly operation, etc. It is excellent and there exists an advantage which can improve manufacturing processes, such as a liquid crystal display device. Suitable lamination means, such as an adhesion layer, can be used for lamination. At the time of adhering the above-mentioned polarizing plate and another optical layer, these optical axes can be made into an appropriate arrangement angle according to the phase difference characteristic made into the objective.

Moreover, in each layer, such as an optical film and an adhesive layer of the adhesive optical film of this invention, a salicylic acid ester type compound, a benzophenol type compound, a benzotriazole type compound, a cyanoacrylate type compound, a nickel complex salt type compound, for example The thing which gave ultraviolet absorption ability by methods, such as a process with a ultraviolet absorber, such as these, etc. may be sufficient.

The adhesive optical film of this invention can be used suitably for formation of various image display apparatuses, such as a liquid crystal display device. Formation of a liquid crystal display device can be performed according to the prior art. In other words, a liquid crystal display device is generally formed by appropriately assembling a component such as a liquid crystal cell, an adhesive optical film, and a lighting system, and inserting a driving circuit, if necessary, according to the present invention. There is no limitation in particular except the point which uses an adhesive optical film, and it can follow conventionally. Also about a liquid crystal cell, arbitrary types, such as a TN type, STN type, (pi) type, can be used, for example.

Suitable liquid crystal display devices, such as the liquid crystal display device which arrange | positioned the adhesive optical film on the one side or both sides of a liquid crystal cell, and the thing which used the backlight or the reflecting plate for the illumination system, can be formed. In that case, the optical film by this invention can be formed in the one side or both sides of a liquid crystal cell. When forming an optical film in both sides, they may be the same and may differ. At the time of formation of the liquid crystal display device, for example, a diffuser plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, or the like and an appropriate component at one or two or more layers in appropriate positions. Can be placed.

Next, an organic electro luminescence apparatus (organic EL display apparatus) is demonstrated. The optical film (polarizing plate etc.) of this invention is applicable also in an organic electroluminescence display. In general, an organic EL display device forms a light emitting body (organic electroluminescent light emitting body) by sequentially stacking a transparent electrode, an organic light emitting layer, and a metal electrode on a transparent substrate. Here, an organic light emitting layer is a laminated body of various organic thin films, For example, the laminated body of the hole injection layer which consists of triphenylamine derivatives, etc., and the light emitting layer which consists of fluorescent organic solids, such as anthracene, or such a light emitting layer, and the The structure which has various combinations, such as the laminated body of the electron injection layer which consists of a rylene derivative | guide_body, etc., or these laminated bodies of a hole injection layer, a light emitting layer, and an electron injection layer is known.

In the organic EL display device, by applying a voltage to the transparent electrode and the metal electrode, holes and electrons are injected into the organic light emitting layer, and energy generated by the recombination of these holes and electrons excites the fluorescent material, and the excited fluorescent material It emits light on the principle of emitting light when returning to the ground state. The recombination mechanism in the middle is the same as that of a general diode, and as can be expected from this, the current and the luminescence intensity exhibit strong nonlinearity accompanied by rectification with respect to the applied voltage.

In the organic EL display device, at least one electrode must be transparent in order to extract light from the organic light emitting layer, and a transparent electrode formed of a transparent conductor such as indium tin oxide (ITO) is usually used as an anode. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a small work function material for the cathode, and metal electrodes such as Mg-Ag and Al-Li are usually used.

In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film with a thickness of about 10 nm. For this reason, like the transparent electrode, the organic light emitting layer also transmits light almost completely. As a result, when the light is incident from the surface of the transparent substrate during non-emission, and the light reflected through the transparent electrode and the organic light emitting layer and reflected from the metal electrode again comes out to the surface side of the transparent substrate, when viewed from the outside, the organic EL display device The display surface of looks like a mirror.

An organic EL display device comprising an organic electroluminescent light-emitting body comprising a transparent electrode on the front side of an organic light emitting layer that emits light by application of a voltage and a metal electrode on the back side of the organic light emitting layer. While forming a polarizing plate on the surface side of an electrode, a phase difference plate can be formed between these transparent electrodes and a polarizing plate.

Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, when the phase difference plate is constituted by a quarter wave plate, and the angle between the polarization direction of the polarizing plate and the phase difference plate is adjusted to π / 4, the mirror surface of the metal electrode can be completely shielded.

That is, only the linearly polarized light component is transmitted to the external light incident on the organic EL display device by the polarizing plate. This linearly polarized light is generally elliptically polarized by the retardation plate, but in particular, when the retardation plate is a quarter wave plate and the angle between the polarization direction of the polarizing plate and the retardation plate is? / 4, it is circularly polarized light.

This circularly polarized light penetrates a transparent substrate, a transparent electrode, and an organic thin film, is reflected by a metal electrode, permeate | transmits an organic thin film, a transparent electrode, and a transparent substrate again, and becomes linearly polarized light again to a retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot pass through a polarizing plate. As a result, the mirror surface of a metal electrode can be shielded completely.

Example

Although an Example demonstrates this invention concretely below, this invention is not limited by these Examples.

Example 1

<Preparation of Adhesives>

In a four-necked flask equipped with a cooling tube, a stirring blade, and a thermometer, 87 parts by weight of butyl acrylate, 13 parts by weight of phenoxyethyl acrylate, and 0.1 parts by weight of 2,2'-azobisisobutyronitrile 140 parts by weight of ethyl acetate The mixture was added together with nitrogen to be sufficiently nitrogen-substituted and then reacted at 55 ° C. for 8 hours while stirring under a nitrogen stream to obtain a solution of an acrylic polymer having a weight average molecular weight of 1.7 million (molecular weight of 100,000 or less: 3 area%). 0.6 parts by weight of a polyisocyanate-based crosslinking agent (colonate L, manufactured by Nippon Polyurethane Co., Ltd.) consisting of tolylene diisocyanate adduct of trimethylolpropane as a solid content, and a silane coupling agent (to 100 parts by weight of the solid content of the acrylic polymer solution) 0.1 weight part of Shin-Etsu Silicone Co., Ltd. product, KBM403) was added, and the adhesive solution was produced.

<Formation of Adhesive Layer>

On the separator which consists of a polyester film (38 micrometers in thickness) which performed the mold release process, the obtained adhesive solution was apply | coated by the reverse roll coating method so that the thickness of the adhesive layer after drying might be 25 micrometers, and it heated at 130 degreeC for 3 minutes. It processed and the solvent was volatilized and the adhesive layer was obtained.

<Optical film>

A wide view (WV) film manufactured by Fuji Photo Film Co., Ltd. was used. The WV film had a discotic liquid crystal layer in which the discotic liquid crystal molecules were diagonally aligned on the cellulose polymer film which is a transparent base film.

In addition, the WV film was isolate | separated into the diagonal alignment layer of the discotic liquid crystal molecule, and the characteristic in (lambda) = 590 nm was measured in KOBRA-21 ADH by the Oji measurement instrument company. The refractive index of the direction orthogonal to the direction which has the largest refractive index of nx and in-plane maximum refractive index in surface was made into ny and the refractive index of the thickness direction was set to nz. The thickness was d. The transparent support had (DELTA) nd = (nx-ny) xd = 12nm, Rth = (nx-nz) xd = 100nm. On the other hand, the inclination orientation layer measured Δnd = 30 nm, Rth = 150 nm, and the average inclination angle θ = 17 ° as a result of measuring the phase difference by changing the incident angle from −50 ° to 50 ° in the direction in which the optical axis was inclined.

After the saponification process of the transparent base film side of the said WV film, the saponification process surface and the polyvinyl alcohol-type polarizer (Nitto Electric Co., Ltd. product, SEG-5424 WL) were affixed with the polyvinyl alcohol-type adhesive agent. On the other hand, a transparent protective film (triacetyl cellulose film, thickness of 80 µm) was attached to the outer surface of the polarizer with the same polyvinyl alcohol adhesive, thereby producing an optical film (polarizing plate with a viewing angle magnifying film) having a polarizing plate.

<Production of Adhesive Optical Film>

On the surface of the discotic liquid crystal layer of the said polarizing plate with a viewing angle expansion film, the undercoat was apply | coated by the wire bar, and the undercoat layer (thickness 100nm) was formed. As a primer, polyethyleneimine system (Nippon Catalyst Co., Ltd. make, NK-380) was used. Next, the release sheet which provided the said adhesive layer was stuck to the undercoat layer, and the adhesive optical film was produced.

Examples 2-12, Comparative Examples 1-4

In Example 1, reaction conditions were controlled so that the kind or compounding quantity of the monomer component used for preparation of an adhesive was changed as shown in Table 1, and the ratio of the weight average molecular weight and low molecular weight of the acryl-type polymer obtained is Table 1. A pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except for the above. Except Example 5, the ratio of the low molecular weight of an acryl-type polymer was controlled so that the ratio of the low molecular weight might become Table 1 by superposing | polymerizing at the polymerization temperature of 50-60 degreeC for 8 hours. In Example 5, after superposing | polymerizing at 60 degreeC for 4 hours, it superposed | polymerized at 80 degreeC for 2 hours, and it controlled so that the ratio of the low molecular weight might become Table 1. Moreover, except having used the said adhesive solution, it carried out similarly to Example 1, and produced the adhesive optical film.

The following evaluation was performed about the adhesive optical film obtained above. The results are shown in Table 1.

(The peripheral part nonuniformity)

Two sheets of the pressure-sensitive adhesive optical film cut to a size of 420 mm x 320 mm were prepared. This adhesive optical film was affixed by a laminator so that it might become cross nicol on both surfaces of the alkali free glass plate of thickness 0.07mm. Subsequently, autoclave treatment was performed at 50 degreeC and 5atm for 15 minutes. This sample was then subjected to 500 hours of treatment at 100 ° C. (heating) and 60 ° C. and 90% R.H. (humidification), respectively. This was put on the backlight of 10,000 canderas, and light leakage was visually evaluated by the following reference | standard.

(Double-circle): There is no periphery nonuniformity and there is no problem practically.

(Circle): Although the peripheral part nonuniformity is seen a little, there is no problem practically.

(Triangle | delta): Although periphery nonuniformity is seen, there is no problem practically.

X: A lot of peripheral part nonuniformity is seen and there is a problem practically.

(durability)

The adhesive optical film (15 inch size) was affixed on the alkali free glass (Corning 1737, thickness 0.7mm), and the process was performed by 50 degreeC and 0.5 mPa autoclaves for 15 minutes. This sample was then subjected to 500 hours of treatment at 90 ° C. (heating) and 60 ° C. and 95% R.H. (humidification), respectively, and visually evaluated according to the following criteria.

(Circle): There is no peeling, lifting, and foaming between an adhesive optical film and an alkali free glass.

X: There exists peeling, lifting, and foaming between an adhesive optical film and an alkali free glass.

In Table 1, BA: n-butyl acrylate, PEA: phenoxyethyl acrylate,

HPPA: phenoxy-2-hydroxypropyl acrylate,

BzA: benzyl acrylate,

IBXA: isobonylkishiacrylate,

CHA: cyclohexyl acrylate,

AA: acrylic acid,

DMAEA: dimethylaminoethyl acrylate,

MEA: methoxyethyl acrylate,

HBA: 2-hydroxybutyl acrylate.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows an example of the adhesive optical film of this invention.

It is sectional drawing which shows an example of the adhesive optical film of this invention.

It is sectional drawing which shows an example of the adhesive optical film of this invention.

Explanation of the sign

1 transparent base film

2 alignment layer

3 discotic liquid crystal layer

4 subfloor

5 adhesive layer

6 polarizer

7 transparent protective film

Claims (10)

In the adhesive optical film in which the adhesive layer is formed on the said discotic liquid crystal layer of the optical film which has a discotic liquid crystal layer on the single side | surface of a transparent base film, The said adhesive layer contains the weight average molecular weight 1 million-3 million acrylic polymer containing a alkyl (meth) acrylate (a1) and (meth) acrylate (a2) which has a ring structure as a monomer unit, and a crosslinking agent. The pressure-sensitive adhesive optical film, which is formed of a pressure-sensitive adhesive. The method of claim 1, The acrylic polymer is a monomer unit, 30 to 90% by weight of alkyl (meth) acrylate (a1), The adhesive optical film containing (meth) acrylate (a2) which has a ring structure in 10 to 70weight% of the ratio. The method of claim 2, The acrylic polymer further contains a monomer (a3) in an amount of 10% by weight or less, except for the component (a1) and the component (a2), as a monomer unit. The method of claim 1, (Meth) acrylate (a2) which has ring structure is (meth) acrylate which has aromatic ring structure, The adhesive optical film characterized by the above-mentioned. The method of claim 1, The acrylic polymer has a weight average molecular weight of 1 million-3 million, and the ratio of molecular weight 100,000 or less is 15 area% or less, The adhesive optical film characterized by the above-mentioned. The method of claim 1, An adhesive contains a silane coupling agent, The adhesive optical film characterized by the above-mentioned. The method of claim 1, The pressure-sensitive adhesive layer is formed on the discotic liquid crystal layer via the undercoat layer. The method of claim 7, wherein The undercoating layer is formed of a polyethyleneimine-based material. The method of claim 1, The optical film is a pressure-sensitive adhesive optical film, wherein a polarizer is laminated on one side of the transparent base film on the side where the discotic liquid crystal layer is not formed. The adhesive optical film in any one of Claims 1-9 is used, The image display apparatus characterized by the above-mentioned.

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