TWI530733B - Polarizing element and manufacturing method thereof - Google Patents

Description

Polarizing element and method of manufacturing same

The present invention relates to a polarizing element, a method of manufacturing the same, and the like.

A polarizer used in a liquid crystal display device includes an optical film such as a protective layer, a polarizing layer, and a transparent substrate. For example, Patent Document 1 discloses a polarizing element in which a transparent resin protective layer (protective film), a light absorbing anisotropic layer (polarizing film), and a transparent film (transparent substrate) are sequentially laminated on a transparent film (transparent substrate). The light absorbing anisotropic layer is a dichroic dye having a nematic liquid crystal property of a specific structure.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-152351

The present invention provides a novel polarizing element and a method of manufacturing the same.

The present invention includes the following inventions [1] to [18].

[1] A polarizing element in which an alignment layer, a polarizing layer, and a protective layer are sequentially provided on a transparent substrate, and the polarizing layer is produced by a manufacturing method comprising the following steps: comprising a polymerizable liquid crystal compound a composition of a dichroic dye, a polymerization initiator, and a solvent to form a film; the solvent is removed from the film; The polymerizable liquid crystal compound contained in the film from which the solvent has been removed is formed into a smectic liquid crystal state; and the polymerizable liquid crystal compound is maintained in the smectic liquid crystal state to be polymerized.

[2] The polarizing element according to [1] above, wherein the polarizing layer is a polarizing layer that obtains a Bragg peak in an X-ray diffraction measurement.

[3] The polarizing element according to the above [1] or [2] wherein the thickness of the polarizing layer is in the range of 0.5 to 3 μm.

[4] The polarizing element according to any one of [1] to [3] wherein the dichroic dye is an azo dye.

[5] The polarizing element according to any one of the above [1] to [4] wherein the polymerizable liquid crystal compound contains two or more polymerizable smectic liquid crystal compounds.

[6] The polarizing element according to any one of [1] to [5] wherein the protective layer is formed of a protective layer composition comprising a polyfunctional acrylate and a solvent, and the solvent substantially comprises an alcohol solvent/or Ether solvent.

[7] The polarizing element according to any one of [1] to [5] wherein the protective layer is a protective layer forming composition comprising a polymer or oligomer obtained by polymerizing a polyfunctional acrylate and water. Object formation.

[8] The polarizing element according to any one of [1] to [5] wherein the protective layer is formed of a composition for forming a protective layer comprising a water-soluble polymer and water.

[9] A liquid crystal display device comprising the polarizing element according to any one of [1] to [8] above.

[10] The liquid crystal display device according to [9] above, wherein the polarizing element is disposed inside the liquid crystal cell.

[11] A circular polarizing plate provided with a quarter-wave plate on the protective layer of the polarizing element according to any one of the above [1] to [8].

[12] The circularly polarizing plate according to [11] above, wherein the quarter-wavelength plate has a wavelength plate having a characteristic that the in-plane retardation value with respect to visible light becomes shorter as the wavelength becomes shorter.

[13] An organic EL (Electroluminescence) display device comprising the circular polarizing plate of [11] or [12] above, and an organic EL device.

[14] A method of producing a polarizing element, comprising: a step (1) of forming an alignment layer on a transparent substrate to form a laminate; and a step (2) of coating the alignment layer on the laminate a composition of a polymerizable liquid crystal compound, a dichroic dye, and a polymerization initiator, and a first coating film formed on the alignment layer; and a step (3) of the above-mentioned step formed by the above step (2) 1 coating film is dried under the condition that the polymerizable liquid crystal compound contained in the first coating film is not polymerized, thereby forming a first dry film, and the first dry film is used in the first dry film After the polymerizable liquid crystal compound forms a smectic liquid crystal state, the polymerizable liquid crystal compound is polymerized in the smectic liquid crystal state to form a polarizing layer, and the step (4) is used. A protective layer composition containing a polyfunctional acrylate and a solvent is applied onto the polarizing layer formed in the step (3), and a second coating film is formed on the polarizing layer, and the second coating film is formed in the second coating film. The above-mentioned polyfunctional acrylate is polymerized, thereby forming from the second coating film The protective layer.

[15] The method for producing a polarizing element according to [14] above, wherein said protective layer The solvent contained in the composition substantially comprises an alcohol solvent and/or an ether solvent.

[16] A method of producing a polarizing element, comprising: a step (1) of forming an alignment layer on a transparent substrate to form a laminate; and a step (2) of coating the alignment layer on the laminate a composition of a polymerizable liquid crystal compound, a dichroic dye, and a polymerization initiator, and a first coating film formed on the alignment layer; and a step (3) of the above-mentioned step formed by the above step (2) 1 coating film is dried under the condition that the polymerizable liquid crystal compound contained in the first coating film is not polymerized, thereby forming a first dry film, and the first dry film is used in the first dry film After the polymerizable liquid crystal compound forms a smectic liquid crystal state, the polymerizable liquid crystal compound is polymerized in the smectic liquid crystal state to form a polarizing layer, and the step (4) is used. The polarizing layer formed by the above step (3) is coated with a protective layer forming composition containing a polymer or oligomer obtained by polymerizing a polyfunctional acrylate and water, and a second layer is formed on the polarizing layer. Coating the film and drying the second coating film, thereby applying the second coating The film forms a protective layer.

[17] A method of producing a polarizing element, comprising: a step (1) of forming an alignment layer on a transparent substrate to form a laminate; and a step (2) of coating the alignment layer on the laminate. a composition of a polymerizable liquid crystal compound, a dichroic dye, and a polymerization initiator, and a first coating film formed on the alignment layer; and a step (3) of the above-mentioned step formed by the above step (2) 1 coating film without polymerizing the above polymerizable liquid crystal compound contained in the first coating film Drying is carried out to form a first dry film, and after the polymerizable liquid crystal compound in the first dry film is formed into a smectic liquid crystal state, the polymerizable liquid crystal compound is maintained in the smectic type. Polymerization is carried out in a liquid crystal state to form a polarizing layer from the first dry film; and step (4) is applied to the polarizing layer formed by the step (3) to apply a water-soluble polymer and water. A protective layer forming composition is formed on the polarizing layer to form a second coating film, and the second coating film is dried to form a protective layer from the second coating film.

[18] A polarizing element produced by the production method according to any one of [14] to [17] above.

According to the present invention, a polarizing element comprising a novel polarizing layer can be provided.

The polarizing element of the present invention (hereinafter sometimes referred to as "the present polarizing element") is provided with an alignment layer, a polarizing layer, and a protective layer on a transparent substrate, and the polarizing layer is manufactured by the following steps. a method of: forming a coating film from a composition comprising a polymerizable liquid crystal compound, a dichroic dye, a polymerization initiator, and a solvent; removing the solvent from the coating film; and removing the coating film from the solvent The polymerizable liquid crystal compound contained is formed into a smectic liquid crystal state; and the polymerizable liquid crystal compound is polymerized while maintaining the smectic liquid crystal state.

Hereinafter, a preferred embodiment of the method for manufacturing the polarizing element will be described with reference to FIG. 1 as needed. A preferred embodiment of the manufacturing method comprises the steps of: (1) forming an alignment layer on a transparent substrate to form a laminate; and the step (2), wherein the laminate is formed by the above step (1) Applying a composition containing a polymerizable liquid crystal compound, a dichroic dye, and a polymerization initiator to the alignment layer, forming a first coating film on the alignment layer; and step (3), which is performed by the above steps (2) The first coating film formed is dried under the condition that the polymerizable liquid crystal compound contained in the first coating film is not polymerized, thereby forming a first dry film, and (1) After the polymerizable liquid crystal compound in the dried film is formed into a smectic liquid crystal state, the polymerizable liquid crystal compound is maintained in the smectic liquid crystal state and polymerized, whereby the first dry film forms a polarizing layer; and the step (4) applying a protective layer composition containing a polyfunctional acrylate and a solvent to the polarizing layer formed by the above step (3), and forming a second coating film on the polarizing layer, and Polymerization of the above polyfunctional acrylate contained in the second coating film The protective layer is formed by the second coating film. Hereinafter, such a manufacturing method will be described for each step.

<Transparent substrate>

In the method for producing the polarizing element, first, a transparent substrate is prepared. The transparent substrate is a substrate having transparency to the extent that it transmits light, particularly visible light. The transparency means a characteristic that the transmittance of light having a wavelength of 380 to 780 nm is 80% or more. Specifically, examples of such a transparent substrate include a glass substrate, a translucent sheet made of plastic, and a translucent film. In addition, examples of the plastic constituting the light-transmitting sheet or the light-transmitting film include polyethylene, polypropylene, and Polyolefin such as olefinic polymer; cyclic olefin resin; polyvinyl alcohol; polyethylene terephthalate; polymethacrylate; polyacrylate; triacetyl cellulose, diethyl cellulose and acetic acid Cellulose esters such as cellulose propionate; polyethylene naphthalate; polycarbonate; polyfluorene; polyether oxime; polyether ketone; polyphenylene sulfide and polyphenylene ether. In the specific example of the above transparent substrate, the translucent sheet made of plastic and the translucent film are preferably a translucent film made of plastic, that is, a polymer film. In the polymer film, a polymer film (cellulose ester film or cyclic olefin) containing a cellulose ester or a cyclic olefin resin is preferable because it can be easily obtained from the market or is excellent in transparency. Resin film). When the polarizing element is produced by using such a transparent substrate, the transparent substrate can be attached to the transparent substrate without being damaged by breakage or the like when transporting or storing the transparent substrate. On the material. Further, the thickness of the transparent substrate may be such a degree as to exhibit the above transparency. Moreover, when a polymer film is used as a transparent substrate, the polymer film can be provided as a function of a retardation film by stretching treatment or the like. In addition, when the function of providing a transparent substrate as a retardation film is added, it demonstrates further.

Further, the cellulose ester film and the cyclic olefin resin film will be described in detail. In addition, in the case where the cyclic olefin resin film is provided as a function of the retardation film, it is also preferable to control the phase difference value.

At least a part of the hydroxyl group contained in the cellulose ester-based cellulose constituting the cellulose ester film is acetate-formed. a cellulose ester film comprising such a cellulose ester Easily obtained from the market. As a commercially available cellulose ester film (triethylene cellulose film), for example, "Fujitac Film" (Fuji Film Co., Ltd.); "KC8UX2M", "KC8UY", and "KC4UY" (Konica Minolta Opto) Wait. Such a commercially available cellulose film can be used as a transparent substrate by directly or optionally subjecting its surface to an anti-glare treatment, a hard coating treatment, an antistatic treatment, or an anti-reflection treatment.

When the phase difference of the polymer film is imparted, as described above, a method of stretching the polymer film or the like is used. The polymer film containing a plastic resin, that is, a thermoplastic resin, may be subjected to a stretching treatment. However, a cyclic olefin resin film is preferred because it is easy to impart phase difference. The cyclic olefin-based resin constituting the cyclic olefin-based resin film contains, for example, a lowering Alkene or polycyclic drop A polymer or a copolymer (cyclic olefin resin) of a cyclic olefin such as an olefinic monomer, and the cyclic olefin resin may partially contain a ring-opening portion. Further, it may be a hydrogenated cyclic olefin resin containing an open ring portion. Further, the cyclic olefin-based resin may be, for example, a cyclic olefin and a chain olefin or an ethylated aromatic compound (styrene) in terms of not significantly impairing transparency or not significantly increasing hygroscopicity. Copolymers. Further, the cyclic olefin resin may be introduced into a polar group in its molecule.

When the cyclic olefin resin is a copolymer of a cyclic olefin and a vinyl compound or a chain olefin, the chain olefin may be ethylene or propylene or the like, and may be an alkylated aromatic compound. It is styrene, α-methylstyrene, and alkyl-substituted styrene. In such a copolymer, the content ratio of the structural unit derived from the cyclic olefin is 50% by mole or less, for example, 15 to 50% by mole based on all structural units of the cyclic olefin-based resin. The range around. In the case where the cyclic olefin resin is a terpolymer obtained from a cyclic olefin, a chain olefin, or an ethylene compound, for example, a content ratio of a structural unit derived from a chain olefin is relative to the ring The structural unit of the olefin resin is about 5 to 80 mol%, and the content of the structural unit derived from the vinylated aromatic compound is about 5 to 80 mol%. The cyclic olefin-based resin of such a terpolymer has an advantage of being able to relatively reduce the amount of use of a high-priced cyclic olefin when the cyclic olefin-based resin is produced.

A cyclic olefin resin which can produce a cyclic olefin resin film is also easily obtained from the market. Examples of the commercially available cyclic olefin-based resin include "Topas" [Ticona (independent)]; "ARTON" [JSR (share)]; "ZEONOR" and "ZEONEX" [Japan ZEON (share)]; APEL" [Mitsui Chemical Co., Ltd.] and so on. For example, such a cyclic olefin-based resin can be formed into a film (cyclic olefin-based resin film) by a known film forming method such as a solvent casting method or a melt extrusion method. Further, a cyclic olefin-based resin film which has been commercially available in the form of a film can also be used. Examples of the commercially available cyclic olefin-based resin film include "S-SINA" and "SCA40" [Sekisui Chemical Industry Co., Ltd.]; "ZEONOR FILM" [Optes (share)]; "ARTON FILM" [JSR (shares)] and so on. In addition, the names described in " " here are all product names, and the same applies hereinafter.

Next, a method of imparting phase difference to the polymer film will be briefly described. The polymer film can impart phase difference by a known stretching method. For example, a coiled body in which a polymer film is wound up onto a roll is prepared, a film is continuously wound up from the wound body, and the film which is wound up is conveyed into a heating furnace. Setting temperature of the heating furnace The range of the glass transition temperature (°C) to [glass transition temperature +100] (°C) of the plastic constituting the polymer film is preferably set to be near the glass transition temperature (°C) to [glass transition temperature +50]. (°C) range. In the heating furnace, when the film advances in the direction orthogonal to the advancing direction or the direction orthogonal to the advancing direction, the conveying direction or the tension is adjusted, the inclination is an arbitrary angle, and the uniaxial or biaxial thermal stretching treatment is performed. The magnification of the stretching is usually in the range of about 1.1 to 6 times, preferably in the range of about 1.1 to 3.5 times. Further, the method of extending in the oblique direction is not particularly limited as long as the alignment axis can be continuously inclined to a desired angle, and a known extension method can be employed. Examples of such an extension method include those described in JP-A-2005-83482 or JP-A-2-113920.

When used as a transparent substrate, the thickness of the polymer film is preferably thin in terms of the weight to which practical treatment is possible and the transparency is ensured, but if it is too thin There is a tendency that the strength is lowered and the workability is poor. Therefore, the appropriate thickness of the films is, for example, about 5 to 200 μm, preferably 20 to 100 μm. When the present polarizing element is used as the circular polarizing plate described below, when the display device using the circular polarizing plate is used for mobile use, the thickness of the film is particularly preferably about 20 to 80 μm. Further, in the case where the phase difference of the film is imparted by stretching, the thickness after stretching is determined by the thickness or the stretching ratio of the film before stretching.

<Step (1)>

In the step (1), an alignment layer is provided on the transparent substrate to form a laminate including a transparent substrate and an alignment layer, preferably a laminated transparent substrate and an alignment layer. Furthermore, hardening the transparent substrate In the case of surface treatment such as coating treatment or anti-glare treatment, an alignment layer may be formed on the surface opposite to the surface-treated surface.

<Alignment layer>

The alignment layer is preferably not significantly modified during the formation of the polarizing layer described below. Examples of the method of forming the alignment layer include a method of using an alignment polymer capable of imparting an alignment regulating force by rubbing (hereinafter, referred to as "friction method"), and a method of using polarized light by irradiation. A method of forming a photo-alignment polymer having an alignment regulating force (hereinafter, referred to as "photo-alignment method"), and a method of forming an alignment layer by obliquely vapor-depositing yttrium oxide on a transparent substrate (surface of a transparent substrate) And a method of forming an alignment layer by forming a monomolecular film having a long-chain alkyl group by using the Langmuir-Blodgett method (LB method). Among them, a rubbing method and a photo-alignment method are preferred in terms of obtaining an alignment layer having excellent alignment uniformity, processing time for forming an alignment layer, and processing cost. As the alignment layer, it is preferred to have solvent resistance to the solvent contained in the composition (the composition for forming a polarizing layer described below) to be applied thereto by the subsequent step, solvent removal, etc. The heat resistance of the heat treatment at the time of forming the polarizing layer and the sufficient adhesion to the transparent substrate. Further, when the alignment layer is provided with the alignment force by the rubbing method or the like, since the coating film for forming the alignment layer is rubbed, it is preferable to form the coating film for forming the alignment layer or the coating film. The compound of the alignment layer (for example, the following alignment polymer) has such a property that it is not modified by the friction or the like, or the alignment layer itself is peeled off from the transparent substrate due to the friction or the like. In terms of being able to form such an alignment layer simply, it is preferred to use an alignment polymer or a composition containing an alignment polymer, or a photoalignment. The polymer or composition comprising the photo-alignment polymer forms an alignment layer.

Hereinafter, an alignment polymer and a photo-alignment polymer for forming an alignment layer will be described.

When a preferred alignment polymer is exemplified, a polyamine having a guanamine bond in a molecule; a gelatin; a polyimine having a quinone bond in a molecule; and a polyamine as a hydrolyzate thereof are exemplified. Acid; polyvinyl alcohol; alkyl modified polyvinyl alcohol; polypropylene decylamine; Azole; polyethyleneimine; polystyrene; polyvinylpyrrolidone; polymers such as polyacrylic acid and polyacrylate. These polymers may be used alone or in combination of two or more kinds to form an alignment layer, and a copolymer comprising a plurality of structural units constituting the polymers may be used to form an alignment layer. The above shows a preferred example of the alignment polymer, and among them, polyvinyl alcohol is particularly preferred as the alignment polymer. Further, such an alignment polymer may be known by a polycondensation polymerization such as dehydration polymerization or deamination polymerization, or a chain polymerization such as a radical polymerization, an anionic polymerization or a cationic polymerization, a coordination polymerization or a ring-opening polymerization, depending on the kind thereof. The polymerization method is easy to manufacture.

As the photo-alignment polymer, a polymer having a photosensitive structure is used. When the polymer having a photosensitive structure is irradiated with polarized light, the photo-alignment polymer is aligned by isomerization or crosslinking of the photosensitive structure to be irradiated, and as a result, a film alignment regulation containing the photo-alignment polymer is imparted. Force to form an alignment layer. Examples of the photosensitive structure include an azobenzene structure, a maleimide structure, a chalcone structure, a cinnamic acid structure, a 1,2-vinyl structure, a 1,2-acetylene structure, and a spiropyridine. A structure, a spirobenzopyran structure, and a fulgide structure. have When the polymer of any one of these photosensitive structures is formed in the alignment layer, it may be used alone or in combination of two or more. Further, the photo-alignment polymer may be selected from a polycondensation polymerization such as dehydration polymerization or deamination polymerization, or a known polymerization method such as radical polymerization such as radical polymerization, anionic polymerization or cationic polymerization, coordination polymerization or ring-opening polymerization. A monomer having a photosensitive structure is polymerized and easily produced. Further, a plurality of monomers having different photosensitive structures may be used to form a copolymer.

As a method of forming an alignment layer from an alignment polymer or a photo-alignment polymer, in terms of ease of operation, it is preferred to prepare the alignment polymer or the photo-alignment polymer in a solvent. The composition is formed and the method of using the composition. Hereinafter, the composition in which the alignment layer can be formed may be referred to as "the composition for forming an alignment layer". When the composition for forming an alignment layer is applied, for example, to a transparent substrate, and the solvent is removed from the coating film by a heating operation or a pressure reduction operation or the like, an alignment layer can be easily provided on the transparent substrate. . The solvent used for the composition for forming an alignment layer can be appropriately selected depending on the type and amount of the alignment polymer or photo-alignment polymer to be used, and specific examples thereof include water; methanol, ethanol, and ethylene glycol. Alcohol solvent such as isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve and propylene glycol monomethyl ether; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butane Ester ester solvents such as ester, propylene glycol methyl ether acetate and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone and methyl isobutyl ketone; pentane , an aliphatic hydrocarbon solvent such as hexane or heptane; an aromatic hydrocarbon solvent such as toluene or xylene; a nitrile solvent such as acetonitrile; an ether solvent such as tetrahydrofuran or dimethoxyethane; chloroform and A chlorine such as chlorobenzene is substituted for a hydrocarbon solvent or the like. These solvents may be used singly or in combination of plural kinds.

Further, in order to form the alignment layer, a commercially available composition for forming an alignment layer can also be used. Examples of the commercially available composition for forming an alignment layer include "Sunever" (Nissan Chemical Industries Co., Ltd.) or "Optomer" (JSR (share)). When such a commercially available composition for forming an alignment layer is used, it is advantageous in that it can form an alignment layer having a small unevenness or an alignment layer which is excellent in environmental resistance and mechanical resistance.

As a method of forming an alignment layer using a composition for forming an alignment layer, the composition for forming an alignment layer is applied onto a transparent substrate, followed by heat treatment (annealing) to form an alignment layer on the transparent substrate. A coating film for forming. The thickness of the coating film for forming an alignment layer obtained in such a manner is determined in such a manner that the alignment layer obtained by imparting the alignment regulating force becomes a desired thickness. The thickness of the alignment layer is, for example, 10 nm to 10000 nm, preferably 10 nm to 1000 nm. The thickness of such an alignment layer can be controlled by adjusting the conditions for coating the composition for forming an alignment layer.

Further, an alignment layer is formed by applying an appropriate alignment regulating force to the coating film for forming the alignment layer, and the coating film for forming the alignment layer is rubbed or polarized. By imparting an alignment regulating force, the polymerizable liquid crystal compound contained in the coating film (first coating film) for forming a polarizing layer described below can be aligned in a desired direction. In the case where the first coating film contains a plurality of polymerizable liquid crystal compounds, that is, when the polymerizable liquid crystal mixture is contained, the polymerizable liquid crystal mixture is aligned in a desired direction.

As a method of rubbing the coating film for forming the alignment layer, for example, a rubbing cloth is wound, and a rubbing roller that is rotating is prepared, and the coating film is formed on the transparent substrate (alignment) The layered body of the coating film for layer formation is placed on the stage and conveyed to the rotating rubbing roll, whereby the coating film is brought into contact with the rotating rubbing roll. Further, in the case where the coating film for forming the alignment layer (optical alignment layer) is irradiated with polarized light (preferably, polarized UV (ultraviolet)), the coating film may be subjected to an alignment regulating force. When performing rubbing or polarized light irradiation, a plurality of regions (patterns) having different directions of the slow phase axes can be formed on the obtained polarizing element as long as the shielding is performed.

<Step (2)>

In the step (2), a polarizing layer is provided on the alignment layer formed in the above manner. The polarizing layer included in the present polarizing element is formed by the method as described above. Although there are repetitions, the method is still explained. First, a composition containing a polymerizable liquid crystal compound, a dichroic dye, a polymerization initiator, and a solvent (hereinafter sometimes referred to as "a composition for forming a polarizing layer") is applied onto the alignment layer to form a first The film is coated, and the first coating film is dried to remove the solvent, thereby forming a first dry film. Thereafter, the polarizing layer is formed by polymerizing the polymerizable liquid crystal compound in the first dried film to maintain the liquid crystal state of the smectic phase. In order to carry out the polymerization in which the polymerizable liquid crystal compound is maintained in the smectic liquid crystal state, the phase transition temperature of the polymerizable liquid crystal compound to be used is first measured, and the temperature at which the smectic phase can be maintained is determined in advance, and then lower than the temperature. The polymerizable liquid crystal compound may be polymerized under temperature conditions, but the polymerization temperature at which the polymerizable liquid crystal compound is polymerized is lower. good. Further, the measurement conditions of the phase transition temperature measurement are explained by the examples of the present application.

The thickness of the polarizing layer is usually in the range of 0.5 to 10 μm, and more preferably in the range of 0.5 to 3 μm. Therefore, the thickness of the first coating film is determined in consideration of the thickness of the obtained polarizing layer. Further, the thickness of the polarizing layer is determined by measurement by an interference film thickness meter, a laser microscope or a stylus type film thickness meter.

The polymerizable liquid crystal compound contained in the composition for forming a polarizing layer is a compound having a polymerizable group and exhibiting liquid crystallinity. The polymerizable group means a group which participates in the polymerization reaction of the polymerizable liquid crystal compound.

Examples of the smectic phase include a smectic B phase, a smectic D phase, a smectic E phase, a smectic F phase, a smectic G phase, a smectic H phase, and a smectic phase I phase. A smectic J phase, a smectic K phase, and a smectic L phase. Among them, a smectic-type B-phase, a smectic-type F-phase, a smectic-type I-phase, an inclined smectic-type F-phase, and an inclined smectic-type I-equal high-order smectic phase are preferable, and a stratified type is more preferable. Phase B. When a liquid crystal phase represented by a polymerizable liquid crystal compound can be used as a composition for forming a polarizing layer of the liquid crystal phase, a polarizing layer having a high degree of alignment can be formed.

The compound represented by the formula (1) (hereinafter, referred to as "compound (1)") may be mentioned as a preferable polymerizable liquid crystal composition.

U ¹ -V ¹ -W ¹ -X ¹ -Y ¹ -X ² -Y ² -X ³ -W ² -V ² -U ² (1) [In the formula (1), X ¹ , X ² and X ³ The phenyl group which may have a substituent or the cyclohexane-1,4-diyl group which may have a substituent is represented independently of each other. Wherein at least one of X ¹ , X ² and X ³ is a para-phenyl group which may have a substituent.

Y ¹ and Y ² are independently of each other -CH ₂ CH ₂ -, -CH ₂ O-, -COO-, -OCOO-, a single bond, -N=N-, -CR ^a =CR ^b -, -C ≡C- or -CR ^a =N-. R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

U ¹ represents a hydrogen atom or a polymerizable group.

U ² represents a polymerizable group.

W ¹ and W ² each independently represent a single bond, -O-, -S-, -COO- or -OCOO-.

V ¹ and V ² independently of each other represent an alkanediyl group having 1 to 20 carbon atoms which may have a substituent, and -CH ₂ - constituting the alkanediyl group may be substituted with -O-, -S- or -NH-. ].

In the compound (1), as described above, at least one of X ¹ , X ² and X ³ is a 1,4-phenylene group which may have a substituent, and further preferably at least two of them are A p-phenyl group which may have a substituent.

The above-mentioned para-phenylene group is preferably unsubstituted. The above cyclohexane-1,4-diyl group is preferably a transcyclohexane-1,4-diyl group, and more preferably it is also unsubstituted.

Examples of the substituent which the above-mentioned para-phenylene group or the above-mentioned cyclohexane-1,4-diyl group has may include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group and a butyl group; a cyano group; Atoms, etc. Further, -CH ₂ - constituting the cyclohexane-1,4-diyl group may be substituted with -O-, -S- or -NR-. R is an alkyl group having 1 to 6 carbon atoms or a phenyl group.

Y ^{1 of the} compound (1) is preferably -CH ₂ CH ₂ -, -COO- or a single bond, and Y ^{2 is} preferably -CH ₂ CH ₂ - or -CH ₂ O-.

U ² is a polymerizable group. U ¹ is a hydrogen atom or a polymerizable group, and is preferably a polymerizable group. That is, it is preferable that both U ¹ and U ² are a polymerizable group, and further preferably both are photopolymerizable groups. Here, the photopolymerizable group refers to a group which can participate in a polymerization reaction by an active radical or an acid generated from a photopolymerization initiator described below. When a polymerizable liquid crystal compound having a photopolymerizable group is used, the polymerizable liquid crystal compound can be polymerized under lower temperature conditions, which is also advantageous in this respect.

In the compound (1), the photopolymerizable groups of U ¹ and U ² may be different from each other, but are preferably the same kind of groups. Examples of the photopolymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloxy group, a methacryloxy group, and an oxirane group. , propylene oxide base, and the like. Among them, an acryloxy group, a methacryloxy group, a vinyloxy group, an oxiranyl group, and an propylene oxide group are preferred, and an acryloxy group is more preferred.

As V ¹ and V ² of the alkanediyl group include: a methylene group, an ethyl group extension, propane-1,3-diyl, butane-1,3-diyl, butane-1,4-diyl Pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, decane-1,10-diyl , tetradecane-1,14-diyl and icosane-1,20-diyl and the like. V ¹ and V ^{2 are} preferably an alkanediyl group having 2 to 12 carbon atoms, more preferably an alkanediyl group having 6 to 12 carbon atoms.

Examples of the substituent which the alkanediyl group has may include a cyano group and a halogen atom. However, the alkanediyl group is preferably unsubstituted, and more preferably an unsubstituted and linear alkanediyl group.

W ¹ and W ² are independent of each other, preferably a single bond or -O-.

The compound (1) is a compound represented by any one of Formula (1-1) to Formula (1-21). When the specific example of such a compound (1) has a cyclohexane-1,4-diyl group, it is preferred that the cyclohexane-1,4-diyl group is trans.

The exemplified compound (1) [polymerizable liquid crystal compound] can be used singly or as a mixture of two or more kinds of polymerizable liquid crystals. Further, as described above, the phase transition temperature of the compound (1) is determined, and the polymerizable property of the composition for forming a polarizing layer can be adjusted so that the compound (1) can be polymerized at a temperature lower than the phase transition temperature. A component other than a liquid crystal compound. Examples of the component capable of controlling the polymerization temperature include a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, and the like. The polymerization temperature of the compound (1) can be controlled by appropriately adjusting the kind and amount thereof. In the case where a mixture of two or more compounds (1), that is, a polymerizable liquid crystal mixture, is used in the composition for forming a polarizing layer, the phase transition temperature of the polymerizable liquid crystal mixture is also determined. Thereafter, the polymerization temperature is controlled in the same manner as in the case of the polymerizable liquid crystal compound.

The polymerizable liquid crystal compound used for the composition for forming a polarizing layer is preferably the compound (1), the formula (1-6), the formula (1-7), and the formula (1-7). Formula (1-12) or formula (1-13) is represented. The compound (1) can be easily maintained at a temperature lower than the phase transition temperature by the interaction with the photopolymerization initiator used, that is, the high-order layer is sufficiently maintained. The liquid crystal state of the columns is polymerized. More specifically, by the interaction with the photopolymerization initiator, the compound (1) can sufficiently maintain the liquid crystal of the high-order layer phase at a temperature of 70 ° C or lower, preferably 60 ° C or lower. Aggregate by state.

As described above, the polymerizable liquid crystal compound contained in the composition for forming a polarizing layer may be one type alone or plural kinds, but preferably plural, more preferably in the compound (1) exemplified. Multiple species. Moreover, the polymerizable liquid crystal compound contained in the composition for forming a polarizing layer is preferably a polymerizable smectic liquid crystal compound, and preferably contains a plurality of polymerizable smectic liquid crystal compounds. In addition, the compound (1) represented by the above formula (1-1) to formula (1-21) conforms to the polymerizable smectic liquid crystal compound.

The content ratio of the polymerizable liquid crystal compound in the composition for forming a polarizing layer is preferably from 70 to 99.9% by mass, and more preferably from 90 to 99.9% by mass, based on the solid content of the composition for forming a polarizing layer. When the content ratio of the polymerizable liquid crystal compound is within the above range, the alignment property of the polymerizable liquid crystal compound tends to be high. Here, the solid content component refers to a combination of components obtained by removing a volatile component such as a solvent from the composition for forming a polarizing layer. Measurement. When the compound (1) is used as the polymerizable liquid crystal compound, the content ratio of the compound (1) to the polarizing layer-forming composition may be within the above range. When a plurality of compounds (1) are contained in the composition for forming a polarizing layer, the total content of the compound may be within the above range.

The composition for forming a polarizing layer preferably contains a leveling agent. The leveling agent is a function of adjusting the fluidity of the polymerizable liquid crystal compound to make the first coating film obtained by coating the composition for forming a polarizing layer flatter. As the leveling agent, a surfactant or the like can be used. Further, the leveling agent is preferably at least one selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a compound containing a fluorine atom as a main component.

As a leveling agent containing a polyacrylate compound as a main component, "BYK-350", "BYK-352", "BYK-353", "BYK-354", "BYK-355", "BYK-" 358N", "BYK-361N", "BYK-380", "BYK-381" and "BYK-392" [BYK Chemie].

Examples of the leveling agent containing a fluorine atom-containing compound as a main component include "MEGAFAC R-08", "MEGAFAC R-30", "MEGAFAC R-90", "MEGAFAC F-410", and "MEGAFAC F-" 411", "MEGAFAC F-443", "MEGAFAC F-445", "MEGAFAC F-470", "MEGAFAC F-471", "MEGAFAC F-477", "MEGAFAC F-479", "MEGAFAC F-482" And "MEGAFAC F-483" [DIC (share)]; "Surflon S-381", "Surflon S-382", "Surflon S-383", "Surflon S-393", "Surflon SC-101", "Surflon SC-105", "KH-40" and "SA-100" [AGC SEIMI CHEMICAL (E), "E1830", "E5844" [Daikin Fine Chemical Institute]; "Eftop EF301", "Eftop EF303", "Eftop EF351" and "Eftop EF352" [Mitsubishi Materials Electronic Chemicals] ]Wait.

When the composition for forming a polarizing layer contains a leveling agent, the content thereof is preferably 0.3 parts by mass or more and 5 parts by mass or less, more preferably 0.5 parts by mass or more, based on 100 parts by mass of the polymerizable liquid crystal compound. , 3 parts by mass or less. When the content of the leveling agent is within the above range, the polymerizable liquid crystal composition tends to be horizontally aligned, and the obtained polarizing layer tends to be smoother. On the other hand, when the content of the leveling agent with respect to the polymerizable liquid crystal compound exceeds the above range, there is a tendency that unevenness is likely to occur in the obtained polarizing layer. Further, the composition for forming a polarizing layer may contain two or more kinds of leveling agents.

The composition for forming a polarizing layer contains a dichroic dye. Here, the dichroic dye refers to a dye having a property in which the absorbance in the long-axis direction of the molecule is different from the absorbance in the short-axis direction. The dichroic dye is not particularly limited as long as it has such a property, and the dye may be a pigment. A plurality of the dyes may be used, and a plurality of pigments may be used, or a dye may be combined with a pigment.

The dichroic dye is preferably one having a maximum absorption wavelength (λMAX) in the range of 300 to 700 nm. Examples of such a dichroic dye include acridine dyes. A dye, a cyanine dye, a naphthalene dye, an azo dye, an anthraquinone dye, etc., among them, an azo dye is preferable. Examples of the azo dye include a monoazo dye, a disazo dye, a trisazo dye, a tetrazo pigment, and a quinone azo dye, and a disazo dye and a trisazo dye are preferable.

The azo dye is, for example, a compound represented by the formula (2) (hereinafter sometimes referred to as "compound (2)").

A ¹ (-N=NA ² ) _p -N=NA ³ (2) [In the formula (2), A ¹ and A ³ each independently represent a phenyl group which may have a substituent, and a naphthyl group which may have a substituent Or a monovalent heterocyclic group which may have a substituent. A ² represents a para-phenyl group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, or a divalent heterocyclic group which may have a substituent. The p system represents an integer from 1 to 4. When p is 2 or more, a plurality of A ^{2 's} may be the same or different from each other].

Examples of the monovalent heterocyclic group include quinoline, thiazole, benzothiazole, thienothiazole, imidazole, and benzimidazole. Oxazole and benzo A group obtained by removing one hydrogen atom from a heterocyclic compound such as azole. The group obtained by removing two hydrogen atoms from the heterocyclic compound corresponds to a divalent heterocyclic group, and specific examples of such a heterocyclic compound are as described above.

Examples of the phenyl group, the naphthyl group and the monovalent heterocyclic group in A ¹ and A ³ , and the substituents optionally substituted for the phenyl, naphthalene-1,4-diyl and divalent heterocyclic groups in A ² Examples thereof include an alkyl group having 1 to 4 carbon atoms; an alkoxy group having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group and a butoxy group; and a fluorinated alkyl group having 1 to 4 carbon atoms such as a trifluoromethyl group. a substituted or unsubstituted amine group such as a cyano group; a nitro group; a halogen atom; an amine group, a diethylamino group, and a pyrrolidinyl group (the so-called substituted amine group means having one or two carbon numbers) The amine group of the alkyl group of 1 to 6 or the two substituted alkyl groups is bonded to each other to form an amine group of a C 2-8 alkanediyl group. The unsubstituted amino group is -NH ₂ ). Further, specific examples of the alkyl group having 1 to 6 carbon atoms are the same as those exemplified as the substituent which the phenyl group of the compound (1) has.

In the compound (2), a compound represented by any one of the following formulae (2-1) to (2-6) is preferred.

In the formulae (2-1) to (2-6), B ¹ to B ²⁰ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a cyano group. A nitro group, a substituted or unsubstituted amine group (the substituted amine group and the unsubstituted amine group are as defined above), a chlorine atom or a trifluoromethyl group.

N1 to n4 represent an integer of 0 to 3 independently of each other.

When n1 is 2 or more, the plurality of B ² may be the same or different from each other. When n2 is 2 or more, the plurality of B ⁶ may be the same or different from each other, and when n3 is 2 or more, the plural The B ⁹ groups may be the same or different from each other, and in the case where n4 is 2 or more, the plurality of B ¹⁴ may be the same or different from each other].

Such azo pigments can also be used as readily available from the market. As a commercially available azo dye which can be used for the composition for forming a polarizing layer, there are "NKX2029" and "G205" (manufactured by Hayashiki Biochemical Research Institute).

The above-mentioned anthraquinone dye is preferably a compound represented by the formula (2-7).

In the formula (2-7), R ¹ to R ⁸ each independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom.

R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.

The acridine dye is preferably a compound represented by the formula (2-8).

In the formula (2-8), R ⁹ to R ¹⁵ each independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom.

R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.

As above The pigment is preferably a compound represented by the formula (2-9).

In the formula (2-9), R ¹⁶ to R ²³ each independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom.

R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.

In the above formula (2-7), formula (2-8) and formula (2-9), the alkyl group having 1 to 4 carbon atoms of R ^x means methyl group, ethyl group, propyl group and butyl group. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolylmethyl group, a xylyl group, and a naphthyl group.

The cyanine dye is preferably a compound represented by the formula (2-10) and a compound represented by the formula (2-11).

In the formula (2-10), D ¹ and D ² each independently represent a group represented by any one of the formulae (2-10a) to (2-10d).

The n5 system represents an integer of 1 to 3].

In the formula (2-11), D ³ and D ⁴ each independently represent a group represented by any one of the formulae (2-11a) to (2-11h).

The n6 system represents an integer of 1 to 3].

The content of the dichroic dye in the composition for forming a polarizing layer can be appropriately adjusted according to the type of the dichroic dye, etc., and is preferably 0.1 part by mass or more based on 100 parts by mass of the total of the polymerizable liquid crystal compound. 50 parts by mass or less, more preferably 0.1 parts by mass or more and 20 parts by mass or less, and further It is preferably 0.1 part by mass or more and 10 parts by mass or less. When the content of the dichroic dye is within this range, the polymerizable liquid crystal compound can be polymerized while maintaining the alignment of the polymerizable liquid crystal compound while maintaining the liquid crystal state of the high-order layer phase. When the content of the dichroic dye is too large, there is a hindrance to the alignment of the polymerizable liquid crystal compound. Therefore, the content of the dichroic dye can also be determined within a range in which the polymerizable liquid crystal compound can maintain the liquid crystal state of the high-order layer phase.

The composition for forming a polarizing layer contains a solvent. The solvent is appropriately selected in consideration of the solubility of the polymerizable liquid crystal compound to be used and the like. Among them, an inert solvent which does not significantly hinder the progress of the polymerization reaction of the polymerizable liquid crystal compound is preferred. Examples of such a solvent include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether; ethyl acetate and butyl acetate; Ester solvent such as ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate and ethyl lactate; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and Ketone solvents such as methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane Chlorine-like solvents such as chloroform and chlorobenzene. These solvents may be used singly or in combination of plural kinds.

The content of the solvent is preferably from 50 to 98% by mass based on the total amount of the composition for forming a polarizing layer. In other words, the solid content component in the composition for forming a polarizing layer is preferably from 2 to 50% by mass. When the solid content component is 2% by mass or more, dichroism which is necessary as a polarizing layer included in the polarizing element can be obtained. On the other hand, if the solid content component is 50% by mass or less, there is a cause Since the viscosity of the composition for forming a polarizing layer is lowered, the thickness of the polarizing layer becomes substantially uniform, and thus it is difficult to cause unevenness in the polarizing layer. Moreover, such a solid component may be determined in such a manner that the thickness of the polarizing layer can be formed.

The composition for forming a polarizing layer contains a polymerization initiator. The polymerization initiator is a compound which can initiate polymerization of a polymerizable liquid crystal compound, and is preferably a photopolymerization initiator in terms of starting the polymerization at a lower temperature. Specifically, a compound which generates an active radical or an acid by the action of light can be used as a low temperature (so-called low temperature, as described above, which is 70 ° C or lower, preferably 60 ° C or lower). Photopolymerization initiator. More preferably, the photopolymerization initiator is a radical generated by the action of light.

Examples of the photopolymerization initiator include a benzoin compound, a benzophenone compound, an alkylphenone compound, a mercaptophosphine oxide compound, and the like. Compounds, strontium salts and strontium salts.

Specific examples of the photopolymerization initiator are listed below.

Examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

Examples of the benzophenone compound include benzophenone, methyl benzoyl benzoate, 4-phenyl-benzophenone, and 4-benzylidene-4'-methyldiphenyl. Thioether, 3,3',4,4'-tetrakis(t-butylperoxycarbonyl)benzophenone and 2,4,6-trimethylbenzophenone.

Examples of the phenylalkyl ketone compound include diethoxyacetophenone and 2-methyl-2- Lolinyl-1-(4-methylthiophenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4- Polinylphenyl)butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethane- 1-ketone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2- An oligomer of methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one or the like.

Examples of the fluorenylphosphine oxide compound include 2,4,6-trimethylbenzimidyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzylidene)phenylphosphine oxide. .

As three The compound may, for example, be 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-tri , 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-three 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-three , 2,4-bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)vinyl]-1,3,5-three , 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)vinyl]-1,3,5-three , 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)vinyl]-1,3,5-three And 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)vinyl]-1,3,5-tri Wait.

A photopolymerization initiator can also be used, which can be easily obtained from the market. As a commercially available photopolymerization initiator, "Irgacure 907", "Irgacure 184", "Irgacure 651", "Irgacure 819", "Irgacure 250", "Irgacure 369" (Ciba Japan) (shares)); "Seikuol BZ", "Seikuol Z", "Seikuol BEE" (Seiko Chemicals Co., Ltd.); "Kayacure BP100" (Nippon Chemicals Co., Ltd.); "Kayacure UVI-6992" (manufactured by Dow Corporation) ); "Adeka Optomer SP-152", "Adeka Optomer SP-170" (Adeka (share)); "TAZ-A", "TAZ-PP" (Siber Hegner, Japan); and "TAZ-104" (Sanwa Chemical Co., Ltd.).

The content of the polymerization initiator in the composition for forming a polarizing layer can be appropriately adjusted depending on the type and amount of the polymerizable liquid crystal compound contained in the composition for forming a polarizing layer, for example, 100 in total with respect to the polymerizable liquid crystal compound. The content of the mass of the polymerization initiator is preferably from 0.1 to 30 parts by mass, more preferably from 0.5 to 10 parts by mass, still more preferably from 0.5 to 8 parts by mass. When the content of the polymerizable initiator is within this range, the polymerization liquid crystal compound can be polymerized without disturbing the alignment of the polymerizable liquid crystal compound. Therefore, the polymerizable liquid crystal compound can be polymerized while maintaining the liquid crystal state of the high-order layer phase.

When the composition for forming a polarizing layer contains a photopolymerization initiator, the composition for forming a polarizing layer may contain a photosensitizer. As the photosensitizer, for example, Ketone and 9-oxosulfur Wait Ketone compounds (for example, 2,4-diethyl-9-oxosulfur 2-isopropyl-9-oxosulfur Etc.); anthracene and anthracene-containing anthracene (e.g., dibutoxyanthracene, etc.); And red fluorene and the like.

When the composition for forming a polarizing layer is a photopolymerization initiator and a photosensitizer, the polymerization reaction of the polymerizable liquid crystal compound contained in the composition for forming a polarizing layer can be further promoted. The amount of the photo-sensitizer to be used is appropriately adjusted depending on the type and amount of the photopolymerization initiator and the polymerizable liquid crystal compound to be used together. For example, the total amount of the polymerizable liquid crystal compound is preferably 0.1 part by mass. ~30 parts by mass, more preferably 0.5 to 10 parts by mass, still more preferably 0.5 to 8 parts by mass.

As described above, the composition for forming the polarizing layer contains a photosensitization In the case where the polymerization reaction of the polymerizable liquid crystal compound is promoted, the polymerization reaction may be carried out stably, and the composition for forming a polarizing layer may appropriately contain a polymerization inhibitor. The degree of progress of the polymerization reaction of the polymerizable liquid crystal compound can be controlled by containing a polymerization inhibitor.

Examples of the polymerization inhibitor include hydroquinone, alkoxy-containing hydroquinone, alkoxy-containing catechol (for example, butyl catechol), and pyrogallol. Radical supplements such as 2,2,6,6-tetramethyl-1-piperidinyloxy radical; thiophenols; β-naphthylamines and β-naphthols.

In the case where the composition for forming a polarizing layer contains a polymerization inhibitor, the content thereof can be appropriately adjusted depending on the type and amount of the polymerizable liquid crystal compound to be used, the amount of the photosensitizer used, and the like. For example, the content of the polymerization inhibitor in an amount of 100 parts by mass based on the total of the polymerizable liquid crystal compound is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, still more preferably 0.5 to 8 parts by mass. When the content of the polymerization inhibitor is within this range, the polymerizable liquid crystal compound can be polymerized without dispersing the alignment of the polymerizable liquid crystal compound or the polymerizable liquid crystal composition contained in the composition for forming a polarizing layer. Or the polymerizable liquid crystal composition satisfactorily maintains the liquid crystal state of the high-order layer phase to carry out polymerization.

The composition for forming a polarizing layer described above is applied onto an alignment layer of a laminate including a transparent substrate and an alignment layer to obtain a first coating film, which is not contained in the first coating film. The polymerizable liquid crystal compound is dried under the conditions of polymerization to form a first dried film.

The method (coating method) of applying the composition for forming a polarizing layer to the above laminated sheet, for example, extrusion coating method or direct gravure coating Method, reverse gravure coating method, CAP coating method, die coating method, dip coating method, bar coating method, spin coating method, and the like. Further, these coating methods can also be applied when the composition for forming an alignment layer is applied onto a transparent substrate. Further, the coating conditions are set such that the thickness of the obtained polarizing layer is within the above preferred range.

Then, by drying the first coating film, the solvent is removed from the first coating film to form a first dry film. When the solvent is removed, the volatile components other than the solvent contained in the first coating film are also removed. The method of removing the solvent is usually carried out by a drying method (drying method), and a natural drying method, a vent drying method, or a reduced pressure drying method, or a combination thereof. In addition, any of the drying methods may be used, and it is preferred to set the drying conditions so as not to polymerize the polymerizable liquid crystal compound contained in the first coating film.

<Step (3)>

In the step (3), when the liquid crystal state of the polymerizable liquid crystal composition contained in the first dry film is maintained in the smectic liquid crystal state, the polymerizable liquid crystal compound is polymerized. The first dry film forms a polarizing layer.

<Formation of polarizing layer>

In order to make the liquid crystal state of the polymerizable liquid crystal compound contained in the first dry film into a smectic phase (hereinafter, referred to as "layered phase" or "liquid crystal state of a smectic phase"), the first The dried film may be heated to a suitable temperature, in other words, the laminated plate including the first dried film may be heated to an appropriate temperature determined based on the phase transition temperature. Further, in forming the smectic phase, it is preferred to temporarily polymerize the first dry film. After the liquid crystal state of the conjugated liquid crystal compound becomes a nematic phase (nematic liquid crystal state), the nematic phase is transferred to a smectic phase. In order to form a smectic phase through a nematic phase, for example, a method of heating a polymerizable liquid crystal compound contained in the first dry film to a temperature at which a phase transition to a liquid crystal state of a nematic phase is performed is employed, and then the polymerization is carried out. The liquid crystal compound is cooled until the temperature of the liquid crystal state of the column phase of the display layer.

When the liquid crystal state of the smectic phase is formed by the nematic phase, it is particularly preferable that the composition for forming a polarizing layer contains the leveling agent. When the leveling agent is contained in the first dry film in the liquid crystal state, the leveling agent tends to flow through the first dry film, and the polymerizable liquid crystal compound or the polymerizable liquid crystal composition is easily horizontally aligned. The advantages. The temperature at which the nematic phase and the smectic phase are formed is preferably a range of not less than the nematic phase transition point and not more than 100 ° C higher than the nematic phase transition point, more preferably a nematic phase transition point or more, and A range below the temperature of 50 ° C higher than the nematic phase transition point. The heat treatment for aligning the desired liquid crystal phase and the drying treatment of the above solvent can also be carried out simultaneously.

When the polymerizable liquid crystal compound is polymerized, it is preferable to use a polymerizable liquid crystal mixture containing two or more kinds of polymerizable liquid crystal compounds (more preferably, two or more kinds thereof) in order to maintain the liquid crystal state of the smectic phase. The composition for forming a polarizing layer of a polymerizable liquid crystal mixture of a polymerizable smectic liquid crystal compound is used as the polymerizable liquid crystal compound. When the content of each of the polymerizable liquid crystal compounds in the polymerizable liquid crystal composition is adjusted to adjust the composition for forming a polarizing layer, there is an advantage that it can be temporarily formed after forming a liquid crystal state of a smectic phase via a nematic phase. Supercooled, easy and easy The liquid crystal state of the high-order layer phase is maintained.

In the above-mentioned method, the composition for forming a polarizing layer contains a photopolymerization initiator, and the liquid crystal state of the polymerizable liquid crystal compound in the first dried film is a smectic phase, and the polymerizability is obtained. The liquid crystal compound maintains the liquid crystal state of the layer phase and is photopolymerized. In the photopolymerization, the light to be irradiated to the first dry film may be based on the type of the photopolymerization initiator contained in the first dry film or the type of the polymerizable liquid crystal compound (especially the polymerizable liquid crystal compound). The type of the photopolymerizable group and the amount thereof are suitably carried out by light or an active electron beam selected from the group consisting of visible light, ultraviolet light, and laser light. Among them, ultraviolet light is preferred in terms of easy control of the progress of the polymerization reaction or as a device for photopolymerization which can be used by a wide range of users in the art. Therefore, it is preferred to select the type of the polymerizable liquid crystal compound or the photopolymerization initiator contained in the composition for forming a polarizing layer in advance by photopolymerization by ultraviolet light. Further, at the time of polymerization, the polymerization temperature may be controlled by cooling the first dried film together with an appropriate cooling method while performing ultraviolet light irradiation. As long as the polymerization of the polymerizable liquid crystal compound can be carried out at a lower temperature by using such a cooling method, there is an advantage that even when the transparent substrate or the alignment layer is used in a relatively low heat resistance, polarized light can be appropriately formed. Floor. Further, at the time of photopolymerization, a patterned polarizing layer can also be obtained by masking or developing.

By carrying out the above photopolymerization, the polymerizable liquid crystal compound is maintained in a smectic phase, preferably in a liquid crystal state as in the high-order smectic phase as exemplified, to form a polarizing layer. Polymerizable liquid crystal compound or polymerizable liquid crystal group The polarizing layer obtained by polymerizing and maintaining the liquid crystal state of the smectic phase has a polarizing property as compared with the polarizing layer obtained by polymerizing a liquid crystal state of a nematic phase, such as a polymerizable liquid crystal compound. A much higher advantage.

Further, the polarizing layer thus formed is particularly preferable in that a Bragg peak is obtained in the X-ray diffraction measurement. As such a polarizing layer for obtaining a Bragg peak, for example, a polarizing layer which exhibits a diffraction peak derived from a hexatic phase or a crystal phase can be cited. In addition, the measurement conditions of such X-ray diffraction measurement include, for example, the conditions described in the examples of the present application.

<Step (4)>

The step (4) is a step of forming a protective layer on the polarizing layer of the laminate obtained by sequentially providing the alignment layer and the polarizing layer on the transparent substrate obtained by the step (3). In the case where the polarizing layer in the present polarizing element is, for example, a polarizing layer formed by polymerizing a polymerizable liquid crystal compound in a liquid crystal state of a higher order layer phase of a smectic B phase, the polarizing layer may sometimes be caused by a polarizing layer. The environment is obviously degraded. The deterioration of such a polarizing layer can be extremely effectively prevented by forming a protective layer on the polarizing layer.

The step (4) is a step (4-1) of applying the protective layer-forming composition 1 containing a polyfunctional acrylate and a solvent to the polarizing layer formed by the above step (3). Therefore, a second coating film is formed on the polarizing layer, and the polyfunctional acrylate contained in the second coating film is polymerized to form a protective layer from the second coating film; and step (4-2) The polarizing layer formed by the above step (3) The composition 2 for forming a protective layer containing a polymer or oligomer obtained by polymerizing a polyfunctional acrylate and water is applied thereon to form a second coating film on the polarizing layer, and the second coating is applied. a film is dried to form a protective layer from the second coating film; and a step (4-3) of applying the water-soluble polymer and water to the polarizing layer formed by the step (3) The protective layer forming composition 3 forms a second coating film on the polarizing layer, and the second coating film is dried to form a protective layer or the like from the second coating film.

Hereinafter, a method of applying the protective layer forming composition 1 containing a polyfunctional acrylate and a solvent to the polarizing layer formed by the above step (3) to form a second layer on the polarizing layer will be described. The protective film is formed from the second coating film by coating the film and polymerizing the polyfunctional acrylate contained in the second coating film. The method of forming the protective layer by the composition 1 for forming a protective layer also has an advantage that the operation thereof is extremely simple.

<Protective layer forming composition 1>

The protective layer forming composition 1 contains a polyfunctional acrylate and a solvent. The polyfunctional acrylate contained in the composition for forming a protective layer 1 means that two or more molecules selected from the group consisting of acrylate groups (CH ₂ =CH-CO-) and methacrylate groups (CH ₂ = A compound having a liquid crystallinity as in the above compound (1), which is a group of the group consisting of C(CH ₃ )-CO-). Preferred polyfunctional acrylates are compounds having from 2 to 6 groups selected from the group consisting of acrylate groups and methacrylate groups in the molecule. In the following, a polyfunctional acrylate having two such groups is referred to as a "bifunctional acrylate" or the like, and a polyfunctional acrylate having three or more such groups is referred to as " A trifunctional or higher polyfunctional acrylate" or the like.

Further, when the polyfunctional acrylate contained in the protective layer forming composition 1 is selected to form a protective layer by curing the polyfunctional acrylate, the protective layer has transparency to the extent that it transmits light, particularly visible light. Sex. Here, the term "transparency in the degree of transmission of visible light" is the same as that described for the transparent substrate.

Here, preferred polyfunctional acrylates are exemplified.

As a bifunctional acrylate having two groups selected from the group consisting of an acrylate group and a methacrylate group in the molecule, 1,3-butanediol di(meth)acrylate; 3-butanediol (meth) acrylate; 1,6-hexanediol di(meth) acrylate; ethylene glycol di(meth) acrylate; diethylene glycol di(meth) acrylate; Neopentyl glycol di(meth)acrylate; triethylene glycol di(meth)acrylate; tetraethylene glycol di(meth)acrylate; polyethylene glycol diacrylate; double bisphenol A Propylene oxiranyl ethyl ether; ethoxylated bisphenol A di(meth) acrylate; propoxylated neopentyl glycol di(meth) acrylate; ethoxylated neopentyl glycol di(methyl) Acrylate and 3-methylpentanediol di(meth)acrylate.

The trifunctional or higher functional acrylate having 3 to 6 groups selected from the group consisting of an acrylate group and a methacrylate group in the molecule may, for example, be trimethylolpropane III. (meth) acrylate; pentaerythritol tri(meth) acrylate; tris(2-hydroxyethyl)isocyanurate tri(meth) acrylate; ethoxylated trimethylolpropane tris(methyl) Acrylate; propoxylated trishydroxyl Propane tri(meth)acrylate; pentaerythritol tetra(meth)acrylate; dipentaerythritol penta(meth)acrylate; dipentaerythritol hexa(meth)acrylate; tripentaerythritol tetra(meth)acrylate; Pentaerythritol penta (meth) acrylate; tripentaerythritol hexa(meth) acrylate; tripentaerythritol hepta (meth) acrylate; tripentaerythritol octa (meth) acrylate; pentaerythritol tri (meth) acrylate and anhydride a reactant; a reaction of dipentaerythritol penta (meth) acrylate with an acid anhydride; a reaction of tripentaerythritol hepta (meth) acrylate with an acid anhydride; a caprolactone-modified trimethylolpropane tri(meth) acrylate Caprolactone modified pentaerythritol tri(meth)acrylate; caprolactone modified tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate; caprolactone modified pentaerythritol IV (a) Acrylate; caprolactone modified dipentaerythritol penta (meth) acrylate; caprolactone modified dipentaerythritol hexa (meth) acrylate; caprolactone modified tripentaerythritol tetra (meth) acrylate; Caprolactone modified tripentaerythritol penta (meth) propylene Ester; caprolactone modified tripentaerythritol hexa(meth) acrylate; caprolactone modified tripentaerythritol hepta (meth) acrylate; caprolactone modified tripentaerythritol octa (meth) acrylate; caprolactone a reaction product of modified pentaerythritol tri(meth)acrylate and an acid anhydride; a reaction of caprolactone-modified dipentaerythritol penta (meth) acrylate with an acid anhydride, and caprolactone-modified trimellititol seven (meth)acrylic acid a reactant of an ester and an acid anhydride, and the like. In the specific example of the polyfunctional acrylate shown here, the term "(meth)acrylate" means an acrylate or a methacrylate. Further, the term "caprolactone modification" means a ring-opening or a ring-opening polymer in which a caprolactone is introduced between a portion derived from an alcohol of a (meth) acrylate compound and a (meth) acryloxy group. .

In order to obtain a protective layer having a large surface hardness, it is preferred to use a trifunctional or higher polyfunctional acrylate in a specific example of the above polyfunctional acrylate, and it is particularly preferred to use a 6-functional acrylate. Further, the protective layer forming composition 1 may contain one type of polyfunctional acrylate and may contain a plurality of polyfunctional acrylates.

Moreover, the protective layer forming composition 1 can also contain the binder resin in terms of the printability of the protective layer forming composition 1 or the viscosity of the obtained protective layer.

The binder resin may, for example, be a copolymer of at least one monomer selected from the group consisting of an unsaturated carboxylic acid and an unsaturated carboxylic anhydride, and another monomer copolymerizable with the monomer.

Specific examples of the unsaturated carboxylic acid include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; maleic acid, fumaric acid, methyl maleic acid, and methyl group. Unsaturated dicarboxylic acids such as fumaric acid and itaconic acid; mono[2-(methyl)propenyloxyethyl] succinate, mono[2-(methyl)propene oxime An unsaturated mono[(meth)acryloxyalkyl]ester of a polyvalent carboxylic acid having two or more valences such as a hydroxyethyl ester; a hydroxy group and a carboxyl group in the same molecule such as α-(hydroxymethyl)acrylic acid Unsaturated acrylates, etc. The unsaturated carboxylic acid anhydride is suitable as the anhydride of the unsaturated carboxylic acid shown here. Among these, as the monomer for producing the binder resin, acrylic acid, methacrylic acid, maleic anhydride or the like is preferable. The acrylic acid, methacrylic acid and maleic anhydride have good polymerization reactivity when copolymerized with various other monomers, and the obtained binder resin has high glass transition temperature (Tg) and mechanical properties, and is non-sticky. It can be used preferably. again When the binder resin is produced, one type of the monomer selected from the group consisting of an unsaturated carboxylic acid and an unsaturated carboxylic anhydride may be used, and a plurality of kinds may be used.

As another monomer copolymerizable with a monomer selected from the group consisting of an unsaturated carboxylic acid and an unsaturated carboxylic anhydride, methyl (meth)acrylate, ethyl (meth)acrylate, (A) (meth)acrylic acid alkyl esters such as n-butyl acrylate, (butyl) (meth) acrylate and t-butyl (meth) acrylate; cyclohexyl (meth) acrylate, (methyl) 2-methylcyclohexyl acrylate, tricyclo [5.2.1.02,6]decane-8-yl (meth)acrylate (in the technical field, as a conventional name, called (meth)acrylic acid bicyclic Amyl ester), dicyclopentyloxyethyl (meth)acrylate and (meth)acrylic acid Cyclic alkyl (meth) acrylates; cyclohexyl acrylate, 2-methylcyclohexyl acrylate, tricyclo[5.2.1.02,6]decane-8-yl acrylate (in the technical field) In the conventional name, it is called dicyclopentyl acrylate), dicyclopentyloxyethyl acrylate and acrylic acid Cyclic alkyl acrylates such as esters; aryl (meth) acrylates such as phenyl (meth) acrylate and benzyl (meth) acrylate; diethyl maleate, fumaric acid Dicarboxylic acid diesters such as diethyl ester and diethyl itaconate; hydroxyalkyl esters such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; bicyclo [2.2.1 Hept-2-ene, 5-methylbicyclo[2.2.1]hept-2-ene, 5-ethylbicyclo[2.2.1]hept-2-ene, 5-hydroxybicyclo[2.2.1]heptane- 2-ene, 5-carboxybicyclo[2.2.1]hept-2-ene, 5-hydroxymethylbicyclo[2.2.1]hept-2-ene, 5-(2'-hydroxyethyl)bicyclo[2.2. 1]hept-2-ene, 5-methoxybicyclo[2.2.1]hept-2-ene, 5-ethoxybicyclo[2.2.1]hept-2-ene, 5,6-dihydroxybicyclo[ 2.2.1] hept-2-ene, 5,6-dicarboxybicyclo[2.2.1]hept-2-ene, 5,6-di(hydroxymethyl)bicyclo[2.2.1]hept-2-ene, 5,6-bis(2'-hydroxyethyl)bicyclo[2.2.1]hept-2-ene, 5,6-dimethoxybicyclo[2.2.1]hept-2-ene, 5,6-di Ethoxybicyclo[2.2.1]hept-2-ene, 5-hydroxy-5-methylbicyclo[2.2.1]hept-2-ene, 5-hydroxy-5-ethylbicyclo[2.2.1]g 2-ene, 5-carboxy-5-methylbicyclo[2.2.1]hept-2-ene, 5-carboxyl -5-ethylbicyclo[2.2.1]hept-2-ene, 5-hydroxymethyl-5-methylbicyclo[2.2.1]hept-2-ene, 5-carboxy-6-methylbicyclo[2.2 .1]hept-2-ene, 5-carboxy-6-ethylbicyclo[2.2.1]hept-2-ene, 5,6-dicarboxybicyclo[2.2.1]hept-2-ene anhydride (bicycloheptane Dimethic anhydride), 5-t-butoxycarbonylbicyclo[2.2.1]hept-2-ene, 5-cyclohexyloxycarbonylbicyclo[2.2.1]hept-2-ene, 5-phenoxy Carbonylbicyclo[2.2.1]hept-2-ene, 5,6-di(t-butoxycarbonyl)bicyclo[2.2.1]hept-2-ene and 5,6-di(cyclohexyloxycarbonyl) a bicyclic unsaturated compound such as bicyclo [2.2.1] hept-2-ene; N-phenyl maleimide, N-cyclohexyl maleimide, N-benzyl butene Yttrium imine, N-butyl succinimide-3-sandimide imidate benzoate, N-butyl succinimide-4-butyl succinimide butyrate, N - butyl quinone imino-6-m-butyleneimine hexanoate, N-butyl diimide imino-3-butyl succinimide propionate and N-(9-acridine Dicarbonyl quinone imine derivatives such as maleimide; styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, vinyl toluene, Methoxystyrene, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, acrylamide, methacrylamide, vinyl acetate, 1,3-butadiene, isoprene and 2 , 3-dimethyl-1,3-butadiene, and the like.

The solvent to be contained in the protective layer-forming composition 1 is, for example, the same as those exemplified as the solvent contained in the composition for forming a polarizing layer. Among these, it is preferred that the solvent contained in the protective layer-forming composition 1 is a solvent containing a solvent selected from the group consisting of an alcohol solvent and an ether solvent, and further preferably contains substantially an alcohol solvent and/or Ether solvent. Here, the term "solvent substantially including an alcohol solvent and/or an ether solvent" means a solvent which contains almost no solvent other than the alcohol solvent, and contains almost no solvent other than the ether solvent, and contains almost no removal. Any one of the alcohol solvent and a solvent other than the ether solvent. However, in a solvent which substantially contains an alcohol solvent and/or an ether solvent, the amount of water which is not intended to be contained may be contained in a trace amount which can form a protective layer. Examples of the alcohol solvent include methanol, ethanol, butanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether. Examples of the ether solvent include ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate. Among these, the solvent contained in the composition for forming a polarizing layer is more preferably ethanol, isopropyl alcohol, propylene glycol monomethyl ether or propylene glycol monomethyl ether acetate, and a plurality of kinds selected from the group consisting of Mixed solvent.

When the solvent contained in the protective layer forming composition 1 is substantially an alcohol solvent and/or an ether solvent, when the protective layer forming composition 1 is applied onto the polarizing layer, it is not significantly impaired. The alignment state of the polarizing layer maintains the alignment state to form a protective layer. In this respect, if When the solvent contained in the composition for forming a protective layer 1 contains substantially an alcohol solvent and/or an ether solvent, the present polarizing element can be stably produced. Moreover, the method of forming the protective layer by using the composition 1 for forming a protective layer in such a manner is also advantageous in terms of its ease of operation. In addition, the content of the solvent contained in the protective layer-forming composition 1 may be determined in consideration of the coatability when the protective layer-forming composition 1 is applied onto the polarizing layer, for example, with respect to the protective layer. The content of the solvent is preferably from 10 to 80 parts by mass, more preferably from 20 to 60 parts by mass, per 100 parts by mass of the total amount of the composition 1.

When the protective layer is formed from the composition 1 for forming a protective layer, it is necessary to polymerize and harden the polyfunctional acrylate contained in the composition for forming a protective layer 1. In the polymerization of the polyfunctional acrylate, photopolymerization as described in the polymerization of the polymerizable liquid crystal compound contained in the composition for forming a polarizing layer is also preferable. The photopolymerization of the polyfunctional acrylate can be carried out by irradiating visible light or ultraviolet rays to the second dry film formed on the polarizing layer by the composition 1 for forming a protective layer. In order to carry out photopolymerization of the polyfunctional acrylate with high efficiency, it is preferred that the protective layer-forming composition 1 contains a photopolymerization initiator in advance. The photopolymerization initiator is exemplified as the photopolymerization initiator contained in the composition for forming a polarizing layer.

Hereinafter, the operation of forming the protective layer will be briefly explained.

When the protective layer is formed, first, the protective layer forming composition 1 is applied onto the polarizing layer to form a second coating film. The coating method of the composition 1 for forming a protective layer is the same as that described for the method of applying the composition for forming a polarizing layer, for example.

Next, a solvent (preferably an alcohol solvent and/or an ether solvent) is removed from the second coating film obtained by coating on the polarizing layer to obtain a second dry film. Such drying may be carried out in the same manner as exemplified as a drying method in which the first dry film is formed by the first coating film. In the process of drying the second dry film, it is necessary to prevent the unpolymerized polymerizable liquid crystal compound from being mixed into the second dry film from the polarizing layer during drying. Therefore, the temperature condition is preferably in the range of about 0 to 60 ° C, and more preferably in the range of about 20 to 50 ° C. When the solvent contained in the protective layer forming composition 1 is a solvent described as a better one, the second coating film can be dried according to such preferable temperature conditions. Further, since the drying is carried out in such a temperature range, the second coating film can be held under appropriate reduced pressure conditions depending on the type of the solvent contained in the composition 1 for forming a protective layer.

The present inventors have found that when the protective layer forming composition 1 containing substantially an alcohol solvent and/or an ether solvent as a solvent is applied onto the polarizing layer, the properties of the polarizing layer are not impaired. Therefore, when the protective layer forming composition 1 is used to form a protective layer on the polarizing layer, the protective layer can prevent the deterioration of the polarizing layer included in the polarizing element from being deteriorated over time, and can be favorably prevented. The protective layer is formed to damage the properties of the polarizing layer. This effect is not directly found in the manufacture of previous polarizing elements, but is based on the unique insights of the inventors.

In the following, a method of forming a protective layer forming composition containing a polymer or oligomer obtained by polymerizing a polyfunctional acrylate and water is applied to the polarizing layer formed by the above step (3). 2, thereby A second coating film is formed on the polarizing layer, and the second coating film is dried to form a protective layer from the second coating film. The method of forming the protective layer by the protective layer forming composition 2 also has the advantage that the operation is extremely simple.

<Protective layer forming composition 2>

The protective layer forming composition 2 contains a polymer or oligomer obtained by polymerizing a polyfunctional acrylate and water. Examples of the polymer or oligomer obtained by polymerizing a polyfunctional acrylate include an aliphatic urethane urethane or the like.

The content of the water contained in the protective layer-forming composition 2 may be determined in consideration of the coatability when the protective layer-forming composition 2 is applied onto the polarizing layer, for example, the protective layer-forming composition. The total amount of 2 is 100 parts by mass, and the water content is preferably 50 to 99 parts by mass, and more preferably 60 to 95 parts by mass.

Hereinafter, the operation of forming the protective layer will be briefly explained.

When the protective layer is formed, first, the protective layer forming composition 2 is applied onto the polarizing layer to form a second coating film. The coating method of the protective layer forming composition 2 is the same as that described for the method of applying the polarizing layer forming composition, for example.

Next, water was removed from the second coating film to obtain a protective layer. Such drying can be carried out in the same manner as exemplified as the drying method of the first coating film. The temperature condition is preferably in the range of about 0 to 100 ° C, and more preferably in the range of about 20 to 80 ° C.

Hereinafter, a method of coating a protective layer containing a water-soluble polymer and water on the polarizing layer formed by the above step (3) will be described. The composition for forming 3 forms a second coating film on the polarizing layer, and the second coating film is dried to form a protective layer from the second coating film. The method of forming a protective layer by such a composition for forming a protective layer also has an advantage that it is extremely easy to handle.

<Protective layer forming composition 3>

The protective layer forming composition 3 contains a water-soluble polymer and water. Examples of the water-soluble polymer include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinylpyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, and the like, and polyethylene is preferably used. alcohol.

The content of the water contained in the protective layer-forming composition 3 may be determined in consideration of the coatability when the protective layer-forming composition 3 is applied onto the polarizing layer, for example, a combination for forming the protective layer. The total amount of the substance 3 is 100 parts by mass, and the water content is preferably 50 to 99 parts by mass, and more preferably 60 to 95 parts by mass.

Hereinafter, the operation of forming the protective layer will be briefly explained.

When the protective layer is formed, first, the protective layer forming composition 3 is applied onto the polarizing layer to form a second coating film. The coating method of the protective layer forming composition 3 is the same as that described for the method of applying the polarizing layer forming composition, for example.

Next, water was removed from the second coating film to obtain a protective layer. Such drying can be carried out in the same manner as exemplified as the drying method of the first coating film. The temperature condition is preferably in the range of about 0 to 100 ° C, and more preferably in the range of about 20 to 80 ° C.

The thickness of the protective layer may be based on the type of polarizing layer protected by the protective layer The amount is suitably adjusted, for example, preferably in the range of 0.1 to 30 μm, and more preferably in the range of 1 to 5 μm. The measurement of the thickness is also the same as that described for the measurement method of the thickness of the polarizing layer.

<This polarizing element>

The present polarizing element obtained by the manufacturing method including the steps (1) to (4) is provided with a protective layer, and not only the surface of the polarizing layer is excellent in scratch resistance or solvent resistance, but also the heat resistance of the polarizing element itself. It is also excellent in heat and humidity resistance, and in this respect, it is advantageous over the prior polarizing element. Further, in the embodiment of the method for producing the present polarizing element including the steps (1) to (4), various modifications can be made without changing the following aspect: the first dry film of the step (3) is applied to 25 The polymerizable liquid crystal compound or the polymerizable liquid crystal composition contained in the first dry film is polymerized while maintaining the smectic liquid crystal state at a temperature of ±10 °C. For example, it may be configured such that when the laminated substrate of the transparent substrate and the alignment layer of the step (1) is formed or prepared, the transparent substrate itself may have an alignment property, and the alignment layer may be laminated in addition to the alignment layer. The differential film is provided with an alignment layer, a polarizing layer, a retardation layer and a protective layer on the transparent substrate. Further, a resin having a bead shape different in refractive index from that of the ultraviolet absorber or the antistatic agent or the protective layer component may be mixed in the protective layer formed in the step (4). In particular, it is preferred that the composition for forming a protective layer used in the formation of the protective layer is substantially a solvent containing an alcohol solvent and/or an ether solvent, or a solvent containing water as a solvent. Step (4) is carried out using the composition for forming a protective layer of such a solvent.

Above, in the form of a laminate of a transparent substrate/alignment layer/polarizing layer/protective layer In the case of the state, the present polarizing element is described, and a layer other than the layer may be laminated on the polarizing element. As described above, the polarizing element may further include a retardation film, and may further include an antireflection layer or a brightness enhancement film. Further, it is also possible to form a circularly polarizing plate in combination with a quarter-wavelength plate. The quarter-wavelength plate used in the manufacture of the circularly polarizing plate preferably has a characteristic that the in-plane retardation value with respect to visible light becomes smaller as the wavelength becomes shorter.

<Use of the polarizing element>

The polarizing element can be used in various display devices. The display device refers to a device including a display element, and includes a light-emitting element or a light-emitting device as a light-emitting source. Examples of the display device include a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, and an electron emission display device (for example, a field emission display device (FED). ), Surface Conduction Electron Emitter Display (SED), electronic paper (display device using electronic ink or electrophoretic element, plasma display device, projection display device (eg, grid light valve imaging system ( GLV, Grating Light Valve) display device, display device having a digital micro-mirror device (DMD), piezoelectric ceramic display, etc. The liquid crystal display device also includes a transmissive liquid crystal display device and a semi-transmissive liquid crystal display. Any one of a device, a reflective liquid crystal display device, an intuitive liquid crystal display device, and a projection type liquid crystal display device, etc. The display device may be a display device that displays a two-dimensional image, or may display a three-dimensional image. Display device.

The present polarizing element can be used particularly effectively for organic electroluminescence (EL) in particular A display device such as a display device or an inorganic electroluminescence (EL) display device.

Fig. 1 is a schematic view showing the simplest cross-sectional configuration of the polarizing element. The alignment layer 3, the polarizing layer 4, and the protective layer 7 are sequentially laminated from the transparent substrate 2, and the polarizing layer 4 is dispersed in the matrix 5 in which the polymerizable liquid crystal compound is polymerized, and the dichroic dye 6 is dispersed.

FIG. 2 and FIG. 5 are schematic diagrams showing a cross-sectional configuration of a liquid crystal display device (hereinafter sometimes referred to as "the present liquid crystal display device") 10 using the present polarizing element. The liquid crystal layer 17 is sandwiched between two substrates 14a and 14b.

FIG. 4 and FIG. 7 are schematic diagrams showing a cross-sectional configuration of an EL display device (hereinafter sometimes referred to as "the present EL display device") using the present polarizing element.

Fig. 8 is a schematic view showing the configuration of a projection type liquid crystal display device using the present polarizing element.

First, the liquid crystal display device shown in Fig. 2 will be described.

The polarizing element is preferably disposed on the light incident side with respect to the liquid crystal layer. A color filter 15 is disposed on the liquid crystal layer 17 side of the substrate 14a. The color filter 15 is disposed at a position facing the pixel electrode 22 via the liquid crystal layer 17, and the black matrix 20 is disposed at a position facing the boundary between the pixel electrodes. The transparent electrode 16 is disposed on the liquid crystal layer 17 side so as to cover the color filter 15 and the black matrix 20. Further, an overcoat layer (not shown) may be included between the color filter 15 and the transparent electrode 16.

The thin film transistor 21 and the pixel electrode 22 are regularly arranged on the liquid crystal layer 17 side of the substrate 14b. The pixel electrode 22 is disposed at a position facing the color filter 15 with the liquid crystal layer 17 interposed therebetween. Between the thin film transistor 21 and the pixel electrode 22 An interlayer insulating film 18 having a connection hole (not shown) is provided.

As the substrate 14a and the substrate 14b, a glass substrate and a plastic substrate are used. Such a glass substrate or a plastic substrate may be the same as those exemplified as the transparent substrate of the present polarizing element. In the case of the step of heating to a high temperature when the color filter 15 or the thin film transistor 21 formed on the substrate is to be manufactured, a glass substrate or a quartz substrate is preferable.

The thin film transistor can be optimally used depending on the material of the substrate 14b. Examples of the thin film transistor 21 include a high-temperature polycrystalline germanium transistor formed on a quartz substrate, a low-temperature polycrystalline germanium transistor formed on a glass substrate, and an amorphous germanium transistor formed on a glass substrate or a plastic substrate. In order to further reduce the size of the liquid crystal display device, a driver IC (integrated circuit) may be formed on the substrate 14b.

A liquid crystal layer 17 is disposed between the transparent electrode 16 and the pixel electrode 22. The spacer 23 is placed on the liquid crystal layer 17 in order to keep the distance between the substrate 14a and the substrate 14b constant. In addition, although the columnar spacer is shown in FIG. 2, the spacer is not limited to the column shape, and the shape is arbitrary as long as the distance between the substrate 14a and the substrate 14b can be kept constant.

An alignment layer for aligning the liquid crystal in a desired direction may be disposed on a surface of the layer formed on the substrate 14a and the substrate 14b in contact with the liquid crystal layer 17. Further, the polarizing element may be disposed inside the liquid crystal cell, that is, the polarizing element may be disposed on the surface side in contact with the liquid crystal layer 17. Hereinafter, this form will be referred to as "In-cell form". The details of this In-cell form are described below.

Each member is made of a substrate 14a, a color filter 15 and a black matrix 20, and is transparent. The electrode 16, the liquid crystal layer 17, the pixel electrode 22, the interlayer insulating film 18, the thin film transistor 21, and the substrate 14b are sequentially laminated.

The polarizing elements 12a and 12b are provided on the outer sides of the substrate 14a and the substrate 14b of the substrate 14a and the substrate 14b sandwiching the liquid crystal layer 17, and at least one of them is the polarizing element 1.

It is preferable to laminate a phase difference layer (for example, a quarter-wave plate or an optical compensation film) 13a and 13b. By arranging the polarizing element 12b among the two polarizing elements, the liquid crystal display device 10 can be provided with a function of converting incident light into linearly polarized light. Further, depending on the configuration of the liquid crystal display device or the type of the liquid crystal compound contained in the liquid crystal layer 17, the retardation layers 13a and 13b may not be disposed, and the polarizing film may be further provided on the light exit side (outer side) of the polarizing element 1. .

Preferably, the anti-reflection film 11 for preventing reflection of external light is disposed on the outer side of the polarizing element 1 (the outer side of the polarizing element 1 is further provided with a polarizing film).

As described above, the present polarizing element 1 can be used as the polarizing element 12a or 12b of the liquid crystal display device 10 of Fig. 2. By providing the present polarizing element 1 as the polarizing elements 12a and/or 12b, it is possible to achieve a reduction in thickness of the liquid crystal display device 10.

In the case where the present polarizing element 1 is used for the polarizing element 12a or 12b, the order of lamination is not particularly limited. An enlarged view of a portion of A and B surrounded by a broken line will be described with reference to FIG.

Figure 3 is an enlarged schematic cross-sectional view of a portion A of Figure 2. (A1) of FIG. 3 shows a case where the polarizing element 1 is used as the polarizing element 12a, and the transparent substrate 2, the alignment layer 3, the polarizing layer 4, and the protective layer are sequentially disposed from the phase difference layer 13a side. The polarizing element 1 is set in the manner of 7. In addition, (A2) of FIG. 3 shows that the polarizing element 1 is provided such that the protective layer 7, the polarizing layer 4, the alignment layer 3, and the transparent substrate 2 are disposed in this order from the phase difference layer 13a side.

Figure 4 is an enlarged schematic view of a portion B of Figure 2. (B2) in the case where the polarizing element is used as the polarizing element 12b, the transparent substrate 2, the alignment layer 3, the polarizing layer 4, and the protective layer 7 are disposed in this order from the retardation film 13b side. The present polarizing element 1.

A backlight unit 19 as a light source is disposed outside the polarizing element 12b. The backlight unit 19 includes a light source, a light guide, a reflection plate, a diffusion sheet, and a viewing angle adjustment sheet. Examples of the light source include electroluminescence, a cold cathode tube, a hot cathode tube, a light-emitting diode (LED), a laser light source, and a mercury lamp. Further, the type of the polarizing element can be selected in accordance with the characteristics of such a light source.

When the liquid crystal display device 10 is a transmissive liquid crystal display device, white light emitted from a light source in the backlight unit 19 is incident on the light guide body, and the path is changed by the reflector to be diffused by the diffusion sheet. The diffused light is incident from the backlight unit 19 to the polarizing element 12b after being adjusted in such a manner as to have a desired directivity by the viewing angle adjusting sheet.

Only one of the linearly incident light of the non-polarized light is transmitted through the polarizing element 12b of the liquid crystal panel. The linearly polarized light is converted into circularly polarized light or elliptically polarized light by the retardation layer 13b, and sequentially passes through the substrate 14b, the pixel electrode 22, and the like to reach the liquid crystal layer 17.

Here, depending on whether there is a potential difference between the pixel electrode 22 and the opposite transparent electrode 16, the alignment state of the liquid crystal molecules contained in the liquid crystal layer 17 changes. The brightness of the light emitted from the liquid crystal display device 10 is controlled. When the liquid crystal layer 17 is in an alignment state in which the polarized light is directly transmitted, the polarized light transmits the liquid crystal layer 17 and the transparent electrode 16, and light of a specific wavelength range is transmitted through the color filter 15 to reach the polarizing element 12a, and further By the anti-reflection film 11, the liquid crystal display device displays the color determined by the color filter most brightly.

On the other hand, when the liquid crystal layer 17 is in an alignment state in which the polarized light is converted and transmitted, the light transmitted through the liquid crystal layer 17, the transparent electrode 16, and the color filter 15 is absorbed by the polarizing element 12a. Thereby, the pixel displays black. In the alignment state between the two states, the brightness of the light emitted from the liquid crystal display device 10 is also intermediate between the two, so that the pixel displays the intermediate color.

In the case where the liquid crystal display device 10 is a semi-transmissive liquid crystal display device, it is preferably used on the protective layer side of the polarizing element and further laminated with a quarter-wavelength plate. At this time, the pixel electrode 22 includes a transmissive portion formed of a transparent material and a reflecting portion formed of a material that reflects light, and the transmissive portion displays an image in the same manner as the transmissive liquid crystal display device. On the other hand, in the reflecting portion, the external light is incident on the liquid crystal display device from the direction of the anti-reflection film 11, and the circularly polarized light transmitted through the polarizing element passes through the liquid crystal layer by the action of the quarter-wave plate further included in the polarizing element. 17 is reflected by the pixel electrode 22 for display.

Next, a preferred liquid crystal display device (the present liquid crystal display device 24) using the In-cell form of the present polarizing element 1 will be described with reference to FIG.

In the liquid crystal display device 24, an anti-reflection film 11, a substrate 14a, a polarizing element 12a, a phase difference layer 13a, a color filter 15, and a black moment are sequentially laminated. The array 20, the transparent electrode 16, the liquid crystal layer 17, the pixel electrode 22, the interlayer insulating film 18, the thin film transistor 21, the retardation layer 13b, the polarizing element 12b, the substrate 14b, and the backlight unit 19 are preferably configured in this configuration. The present polarizing element 1 is used as the polarizing element 12a. In this configuration, the polarizing element 1 is provided with the transparent substrate 2, the alignment layer 3, the polarizing layer 4, and the protective layer 7 in this order from the anti-reflection film 11 side. The liquid crystal display device 24 including the present polarizing element in such a configuration has a function of causing incident light to be linearly polarized. Further, similarly to the liquid crystal display device 10, the retardation layers 13a and 13b may not be disposed depending on the type of the liquid crystal compound contained in the liquid crystal layer 17.

Next, an EL display device using the present polarizing element will be described with reference to Figs. 4 and 7 .

The EL display device 30 is formed by laminating an organic functional layer 36 as a light-emitting source and a cathode electrode 37 on a substrate 33 on which a pixel electrode 35 is formed. The phase difference plate 32 and the polarizing plate 31 are disposed on the side opposite to the organic functional layer 36 via the substrate 33, and the polarizing plate 1 is used as the polarizing plate 31. The organic functional layer 36 is caused to emit light by applying a positive voltage to the pixel electrode 35, applying a negative voltage to the cathode electrode 37, and applying a direct current between the pixel electrode 35 and the cathode electrode 37. The organic functional layer 36 as a light source includes an electron transport layer, a light emitting layer, a hole transport layer, and the like. The light emitted from the organic functional layer 36 passes through the pixel electrode 35, the interlayer insulating film 34, the substrate 33, the phase difference plate 32, and the polarizing element 31 (the present polarizing element 1). The organic EL display device including the organic functional layer 36 has been described above, and can also be applied to an inorganic EL display device including an inorganic functional layer.

When manufacturing the EL display device 30, first, the thin film is electrically formed on the substrate 33. The crystal 40 is formed into a desired shape. Then, the interlayer insulating film 34 is formed, and then the pixel electrode 35 is formed by sputtering and patterned. Thereafter, the organic functional layer 36 is laminated.

Next, a polarizing element 31 (the present polarizing element 1) is provided on the surface of the substrate 33 opposite to the surface on which the thin film transistor 40 is provided. Preferably, a phase difference layer 32 is provided between the polarizing element 31 and the substrate 33, and it is preferable that the phase difference layer 32 includes a quarter-wave plate. In order to provide the phase difference layer 32, the laminated body 45 in which the polarizing element 31 (the present polarizing element 1) and the phase difference layer 32 are laminated may be prepared in advance, and the laminated body 45 may be bonded to the substrate 33. The outline of the manufacturing method using this laminated body 45 is shown in FIG.

In the case where the present polarizing element 1 is used for the polarizing element 31, the order of lamination is not particularly limited. This will be described with reference to an enlarged view of a portion C surrounded by a broken line in FIG.

Fig. 6 is an enlarged cross-sectional view showing the outline of a portion C of Fig. 4. (C1) of FIG. 6 shows a case where the polarizing element 1 is used as the polarizing element 31, and the transparent substrate 2, the alignment layer 3, the polarizing layer 4, and the protective layer 7 are disposed in this order from the phase difference layer 32 side. The polarizing element 1 is set in a manner. In addition, (C2) of FIG. 6 shows that the polarizing element 1 is provided such that the protective layer 7, the polarizing layer 4, the alignment layer 3, and the transparent substrate 2 are disposed in this order from the phase difference layer 32 side.

Next, members other than the polarizing element of the present EL display device will be briefly described.

Examples of the substrate 33 include a sapphire glass substrate, a quartz glass substrate, a soda glass substrate, and a ceramic substrate such as alumina; a metal substrate such as copper; and a plastic substrate. Although not shown, a thermally conductive film may be formed on the substrate 33.

Examples of the thermally conductive film include a diamond film (DLC, (diamond-like carbon), etc.). When the pixel electrode 35 is of a reflective type, light is emitted in a direction opposite to the substrate 33. Therefore, not only a transparent material but also a non-transmissive material such as stainless steel can be used. The substrate may be formed singly or as a laminated substrate by bonding a plurality of substrates by an adhesive. Moreover, these substrates are not limited to a plate shape, and may be a film.

As the thin film transistor 40, for example, a polycrystalline germanium transistor or the like may be used. The thin film transistor 40 is provided at the end of the pixel electrode 35 and has a size of about 10 to 30 μm. Furthermore, the size of the pixel electrode 35 is about 20 μm × 20 μm to 300 μm × 300 μm.

A wiring electrode of the thin film transistor 40 is provided on the substrate 33. The wiring electrode has a low resistance and is electrically connected to the pixel electrode 35, and has a function of suppressing the resistance value to a low level. Generally, the wiring electrode uses Al, Al, and a transition metal (excluding Ti), Ti or nitrogen. Any one or two or more kinds of titanium (TiN).

An interlayer insulating film 34 is provided between the thin film transistor 40 and the pixel electrode 35. The interlayer insulating film 34 is formed by sputtering or vacuum deposition to form an inorganic material such as cerium oxide or tantalum nitride such as SiO ₂ or oxidized by SOG (spin-on-glass). Any one of insulating layers such as a coating film of a resin material such as a ruthenium layer, a photoresist, a polyimide, or an acrylic resin may be used.

A barrier wall 41 is formed on the interlayer insulating film 34. The barrier 41 is disposed at a peripheral portion of the pixel electrode 35 (between adjacent pixels). Examples of the material of the barrier rib 41 include an acrylic resin and a polyimide resin. The thickness of the barrier wall 41 is relatively Preferably, it is 1.0 μm or more and 3.5 μm or less, more preferably 1.5 μm or more and 2.5 μm or less.

Next, an EL element including a pixel electrode 35 as a transparent electrode, an organic functional layer 36 as a light source, and a cathode electrode 37 will be described. The organic functional layer 36 includes at least one layer of a hole transport layer and a light-emitting layer, and includes, for example, an electron injection transport layer, a light-emitting layer, a hole transport layer, and a hole injection layer.

Examples of the pixel electrode 35 include ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide), IGZO, ZnO, SnO _{2 ,} and In ₂ O ₃ , and particularly preferably ITO or IZO. The thickness of the pixel electrode 35 may be a thickness of a certain thickness or more that can sufficiently fill the hole, and is preferably about 10 to 500 nm.

The pixel electrode 35 can be formed by a vapor deposition method (preferably, a sputtering method). The sputtering gas is not particularly limited, and any inert gas such as Ar, He, Ne, Kr or Xe or a mixed gas thereof may be used.

As a constituent material of the cathode electrode 37, for example, a metal element such as K, Li, Na, Mg, La, Ce, Ca, Sr, Ba, Al, Ag, In, Sn, Zn, or Zr may be used. For the stability of the operation, it is preferred to use an alloy system selected from two or three kinds of metal elements exemplified. As the alloy system, it is preferably, for example, Ag. Mg (Ag: 1~20 at%), Al. Li (Li: 0.3~14 at%), In. Mg (Mg: 50~80 at%) and Al. Ca (Ca: 5 to 20 at%) and the like.

The cathode electrode 37 is formed by a vapor deposition method, a sputtering method, or the like. Preferably, the cathode electrode 37 has a thickness of 0.1 nm or more, preferably 1 to 500 nm or more.

The hole injection layer has a function of facilitating the injection of the hole from the pixel electrode 35, and the hole transport layer has a function of transmitting a hole and a function of blocking electrons, and is also referred to as a charge injection layer or a charge transport layer.

The thickness of the light-emitting layer, the thickness of the hole injection layer and the hole transport layer, and the thickness of the electron injection transport layer are not particularly limited, and are also different depending on the formation method, and are preferably set to about 5 to 100 nm. . For the hole injection layer or the hole transport layer, various organic compounds can be used. When a hole-injecting and transporting layer, a light-emitting layer, and an electron injecting and transporting layer are formed, a vacuum vapor deposition method can be used in terms of forming a homogeneous film.

As the light-emitting source, the organic functional layer 36 can be used: those who emit light from a singlet exciton (fluorescence), those who use light from triplet excitons (phosphorescence), and those that use light from singlet excitons (fluorescence) And those who use luminescence (phosphorescence) from triplet excitons, those formed by organic matter, those formed by organic matter, and those formed by inorganic substances, materials of polymers, and low molecules Materials, materials containing polymers, and materials with low molecular weight. However, the present invention is not limited thereto, and an organic functional layer 36 using a known one as an EL element can be used for the EL display device 30.

A desiccant 38 is disposed in the space between the cathode electrode 37 and the sealing cover 39. This is because the organic functional layer 36 is sensitive to humidity. The desiccant 38 absorbs moisture to prevent deterioration of the organic functional layer 36.

FIG. 8 is a schematic view showing a cross-sectional configuration of another aspect of the EL display device 30. The present EL display device 30 has a sealing structure using a film sealing film 41, and can also emit light from the opposite surface of the array substrate.

The film sealing film 41 is preferably a DLC film obtained by vapor-depositing DLC (Diamond-like carbon) on a film of an electrolytic capacitor. The DLC film has a characteristic of poor moisture permeability and high moisture resistance. Further, a DLC film or the like may be formed by direct vapor deposition on the surface of the cathode electrode 37. Further, a resin film and a metal film may be laminated in a plurality of layers to form a film sealing film 41.

The novel polarizing element (the present polarizing element) of the present invention and the novel display device (the present liquid crystal display device and the present EL display device) including the present polarizing element are provided as described above.

Finally, a projection type liquid crystal display device using the present polarizing element 1 will be described.

Fig. 8 is a schematic view showing a projection type liquid crystal display device using the present polarizing element 1.

The polarizing element 1 is used as the polarizing film 142 and/or the polarizing film 143 of the projection type liquid crystal display device.

The light beam emitted from the light source (for example, the high-pressure mercury lamp) 111 as the light-emitting source is firstly passed through the first lens array 112, the second lens array 113, the polarization conversion element 114, and the superimposing lens 115, and the luminance is reflected on the beam cross section. Homogenization and polarization.

Specifically, the light beam emitted from the light source 111 is divided into a plurality of minute light beams by the first lens array 112 in which the minute lenses 112a are formed in a matrix. Since the second lens array 113 and the superimposing lens 115 are included in the entire three liquid crystal panels 140R, 140G, and 140B to be illuminated by the respective divided light beams, the incident side surface of each liquid crystal panel has a substantially uniform illuminance as a whole.

The polarization conversion element 114 includes an array of polarization beam splitters and is disposed between the second lens array 113 and the overlap lens 115. Thereby, the random polarized light from the light source is previously converted into a polarized light having a specific polarization direction, and the light amount loss of the incident side polarizing element described below is reduced, thereby improving the brightness of the screen.

The light which is uniformized and polarized by the brightness as described above is sequentially separated into red channels by red dichroic mirrors 121, 123, 132 which are separated into three primary colors of RGB via the mirror 122. A channel, a green channel, and a blue channel are incident on the liquid crystal panels 140R, 140G, and 140B, respectively.

The polarizing element film 142 of the present invention is disposed on the liquid crystal panels 140R, 140G, and 140B on the incident side thereof, and the polarizing element film 143 of the present invention is disposed on the emission side.

The polarizing film 142 and the polarizing film 143 disposed in each of the RGB optical paths are disposed such that their absorption axes are orthogonal to each other. Each of the liquid crystal panels 140R, 140G, and 140B disposed in each of the optical paths has a function of converting a polarization state controlled for each pixel into a light amount in accordance with an image signal.

The polarizing element 1 can be used as a polarizing film excellent in durability in any of the blue channel, the green channel, and the red channel by selecting the type of the dichroic dye suitable for the corresponding channel.

The optical image produced by transmitting the incident light at different transmittances for each pixel according to the image data of the liquid crystal panels 140R, 140G, and 140B is synthesized by the combining aperture 150, and by the projection lens 170 is enlarged and projected on the screen 180.

Examples of the electronic paper include those which are displayed by molecules such as optical anisotropy and dye molecule alignment, and are displayed by particles such as electrophoresis, particle movement, particle rotation, and phase change, by moving one end of the film The display person, the display by the color development/phase change of the molecule, the display by the light absorption of the molecule, the combination of the electron and the hole, and the display by self-luminescence. More specifically, microcapsule type electrophoresis, horizontal movement type electrophoresis, vertical movement type electrophoresis, spherical torsion ball, magnetic torsion ball, cylindrical torsion ball method, charged toner, electronic powder fluid, magnetophoresis Type, magnetic thermal type, electrowetting method, light scattering (transparent/white turbidity change), cholesteric liquid crystal/photoconductive layer, cholesteric liquid crystal, bistable nematic liquid crystal, ferroelectric liquid crystal, 2-color pigment. Liquid crystal dispersion type, movable film, hair coloring by leuco dye, photochromism, electron coloration, electrodeposition, flexible organic EL, and the like. Electronic paper can be used not only for individuals to use text or images, but also for advertisement display (signage). According to the optical film of the present invention, the thickness of the electronic paper can be made thin.

As a stereoscopic display device, for example, a method of alternately arranging different retardation films as in the case of the Micro Pol method has been proposed (Japanese Patent Laid-Open Publication No. 2002-185983), and the optical film of the present invention is easily printed by using it as a polarizing film. Patterning is achieved by inkjet, photolithography, etc., so that the manufacturing steps of the display device can be shortened, and a retardation film is not required.

[Examples]

Hereinafter, the present invention will be described in further detail by way of examples. In the examples, "%" and "parts" are % by mass and parts by mass unless otherwise specified.

In the present embodiment, the following polymerizable liquid crystal compound was used.

Compound (1-6) (a compound represented by the following formula (1-6))

Compound (1-6) was synthesized by the method described in Lub et al. Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996).

[Measurement of phase transition temperature]

The phase transition temperature of the compound (1-6) was confirmed by determining the phase transition temperature of the film containing the compound (1-6). Its operation is as follows.

A film containing the compound (1-6) was formed on the glass substrate on which the alignment film was formed, and the phase transition temperature was confirmed by observation using a structure of a polarizing microscope (BX-51, manufactured by Olympus Co., Ltd.) while heating. It was confirmed that when the film containing the compound (1-6) was cooled to 120 ° C and then cooled, the phase was transferred to a nematic phase at 112 ° C, and the phase was transferred to a smectic A phase at 110 ° C, and was passed at 94 ° C. The smectic B phase undergoes phase transfer.

Compound (1-7) (a compound represented by the following formula (1-7))

The compound (1-7) is synthesized by referring to the synthesis of the above compound (1-6).

[Measurement of phase transition temperature]

The phase transition temperature of the compound (1-7) was confirmed in the same manner as the phase transition temperature measurement of the compound (1-6). It was confirmed that the compound (1-7) was phase-transferred to a nematic phase at 133 ° C when the temperature was raised to 140 ° C, and the phase was transferred to a smectic phase A at 118 ° C, and stratified at 78 ° C. Phase B is phased shift.

Example 1 [Preparation of Composition for Polarizing Layer Formation]

The composition for forming a polarizing layer was obtained by mixing the following components and stirring at 80 ° C for 1 hour.

Polymerization initiator: 2-dimethylamino-2-benzyl-1-(4- Polinylphenyl)butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals) 6 parts

Leveling agent:

[Measurement of phase transition temperature]

In the same manner as in the case of the compound (1-6) and the compound (1-7), the phase transition temperature of the polymerizable liquid crystal composition contained in the composition for forming a polarizing layer prepared as described above was determined. It was confirmed that the polymerizable liquid crystal composition was phase-transferred to a nematic phase at 112 ° C when the temperature was raised to 120 ° C, and was phase-transformed into a smectic A phase at 104 ° C, and stratified at 78 ° C. Phase B undergoes phase transfer.

[Manufacture and evaluation of this polarizing element] 1. Formation of alignment layer

A glass substrate was used as the transparent substrate.

On the glass substrate, a 2% by mass aqueous solution (a composition for forming an alignment layer) of polyvinyl alcohol (polyvinyl alcohol 1000 completely saponified, manufactured by Wako Pure Chemical Industries, Ltd.) was applied by a spin coating method. After drying, a film having a thickness of 100 nm was formed. Then, an alignment layer is formed by subjecting the surface of the obtained film to a rubbing treatment. The friction treatment system uses a semi-automatic friction device (trade name: LQ-008 type, manufactured by Changyang Engineering Co., Ltd.), and the cloth is used (trade name: YA-20-RW, manufactured by Yoshikawa Chemical Co., Ltd.) at a press-in amount of 0.15. Mm, speed 500 rpm, 16.7 mm / s. By this rubbing treatment, the laminated body 1 in which the alignment layer is formed on the glass substrate is obtained.

2. Formation of polarizing layer

The composition for forming a polarizing layer was applied onto the alignment layer of the laminate 1 by a spin coating method, and dried by heating on a hot plate at 120 ° C for 3 minutes, and then rapidly cooled to 70 ° C (displayed at the time of cooling) The temperature of the smectic phase is as follows, so that the first dry film is formed on the alignment layer. In the first dry film, the liquid crystal state of the polymerizable liquid crystal compound contained in the first dry film is a smectic B phase. Then, the first dry film was irradiated with ultraviolet rays at an exposure amount of 2400 mJ/cm ² (365 nm basis) using a UV irradiation device (SPOT CURE SP-7; manufactured by Oxtail Electric Co., Ltd.), thereby making the first drying The polymerizable liquid crystal compound contained in the film is polymerized while maintaining the liquid crystal state of the polymerizable liquid crystal composition, and a polarizing layer is formed from the first dry film to obtain a layered body 2. The thickness of the polarizing layer at this time was measured by a laser microscope (manufactured by Olympus Co., Ltd., OLS3000), and it was 1.8 μm.

3. X-ray diffraction measurement

For the polarizing layer of the obtained laminated body 2, X-ray diffraction measurement was performed using an X-ray diffraction apparatus X' Pert PRO MPD (manufactured by Spectris Co., Ltd.). Using Cu as a target, the X-ray generated under the conditions of an X-ray tube current of 40 mA and an X-ray tube voltage of 45 kV is self-friction direction via a fixed divergence slit of 1/2° (predetermined in the polarized light) The rubbing direction of the alignment layer under the layer) is incident, and is scanned in the range of 2θ=0.01671° in the scanning range 2θ=4.0~40.0°, and the peak half-height width is obtained near 2θ=20.22° ( FWHM) = steep diffraction peak (Prague peak) of about 0.187°. Moreover, the same result is obtained from the incidence of the vertical direction of the rubbing. It can be seen that the order period (d) obtained from the peak position is about 4.39 Å, and a structure reflecting the columnar phase of the high-order layer is formed.

4. Manufacture of the present polarizing element formed by the protective layer

On the polarizing layer of the laminate 2, 50 parts of dipentaerythritol hexaacrylate (ARONIX M-403, a polyfunctional acrylate manufactured by Toagosei Co., Ltd.) and an acrylate resin (Ebecryl) were applied by a spin coating method. 4858, manufactured by Daicel-UCB Co., Ltd.) 50 parts, 2-methyl-1[4-(methylthio)phenyl]-2- 3 parts of a solution prepared by dissolving 250 parts of isopropyl alcohol (protective layer-forming composition) in a morphyl propan-1-one (Irgacure 907; manufactured by Ciba Specialty Chemicals Co., Ltd.), and dried by heating on a hot plate at 50 ° C After a minute, a protective layer was formed on the polarizing layer by irradiating ultraviolet rays with an exposure amount of 400 mJ/cm ² (365 nm basis) by using a UV irradiation device (SPOT CURE SP-7; manufactured by Oxtail Electric Co., Ltd.). Thus, the present polarizing element (hereinafter referred to as "the present polarizing element A") is manufactured. The protective layer at this time was measured by a laser microscope (OLS 3000 manufactured by Olympus Co., Ltd.), and the result was 2.8 μm.

5. Determination of dichroic ratio

In order to confirm the usefulness of the present polarizing element, the dichroic ratio was measured in the following manner.

A device equipped with a folder with a polarizing element on a spectrophotometer (UV-3150 manufactured by Shimadzu Corporation) is used to measure the absorbance in the transmission axis direction at a maximum absorption wavelength by a two-beam method ( A ¹ ) and absorbance in the direction of the absorption axis (A ² ). The folder is provided with a mesh that cuts the amount of light by 50% on the reference side. The (A ²⁾ of the values of the transmission axis direction of the absorbance (A ¹⁾ and the absorption axis direction calculated from the measured absorbance ratio (A ² / A ^1), the dichroic ratio is set. The results are shown in the table. The higher the dichroic ratio, the more useful it is as a polarizing film. The measurement results of the two color ratios are shown in Table 1.

Example 2

The same experiment as in Example 1 was carried out except that the dichroic dye was changed from azo dye (NKX2029; manufactured by Hayashiki Biochem Research Institute) to azo dye (G205; manufactured by Hayashiki Biochem Research Institute) to produce the polarizing element. (hereinafter, referred to as "the present polarizing element B"). It was confirmed that the phase transition behavior of the polymerizable liquid crystal composition at this time was such that when the temperature was raised to 120 ° C and then the temperature was lowered, the phase was transferred to a nematic phase at 112 ° C, and the phase was transferred to a smectic A phase at 105 ° C. Phase transfer was carried out to the smectic B phase at 77 °C. The dichroic ratio measurement results of the obtained polarizing element are shown in Table 1.

Example 3

The polarizing element (hereinafter referred to as "the present polarizing element C") was produced by the same experiment as in Example 1 except that the solvent contained in the composition for forming a protective layer was changed from isopropyl alcohol to ethanol. The results of the two-color ratio measurement of the produced polarizing element are shown in Table 1.

Example 4

The polarizing element was produced by the same experiment as in Example 1 except that the solvent contained in the composition for forming a protective layer was changed from isopropyl alcohol to propylene glycol monomethyl ether acetate (hereinafter, referred to as "the present polarizing element D". "). The results of the two-color ratio measurement of the produced polarizing element are shown in Table 1.

Example 5

The polarizing element (hereinafter referred to as "the present polarizing element E") was produced by the same experiment as in Example 1 except that the solvent contained in the composition for forming a protective layer was changed from isopropyl alcohol to propylene glycol monomethyl ether. The results of the two-color ratio measurement of the produced polarizing element are shown in Table 1.

Example 6

On the protective layer of the present polarizing element A obtained by the first embodiment, TAC (triacetyl cellulose, triethylene fluorene fiber) is attached via an adhesive layer formed of a pressure-sensitive adhesive (PSA). Membrane). The results of the measurement of the dichroic ratio of the structure obtained in this manner (hereinafter referred to as "the present polarizing element A + TAC") are shown in Table 1.

Example 7

The protective layer of the present polarizing element B obtained by the second embodiment is adhered to the TAC (triethyl fluorene fiber) via an adhesive layer formed of a pressure sensitive adhesive (PSA). Vitamins) membrane. The results of the measurement of the dichroic ratio of the structure obtained in this manner (hereinafter referred to as "the present polarizing element B + TAC") are shown in Table 1.

Example 8

The surface of the polarizing layer produced in the same manner as in Example 1 was surface-activated by corona treatment, and polyvinyl alcohol (polyvinyl alcohol 1000 completely saponified type) was coated by a spin coating method, and The 10% by mass aqueous solution of Wako Pure Chemical Industries, Ltd. was heated and dried on a hot plate at 80 ° C for 1 minute to form a protective layer on the polarizing layer, thereby producing the present polarizing element (hereinafter, referred to as "the present polarizing light" Element F"). The results of the two-color ratio measurement of the produced polarizing element are shown in Table 1.

Example 9

The surface of the polarizing layer produced in the same manner as in Example 1 was surface-activated by corona treatment, and the solution in which the aliphatic urethane acrylate resin was dispersed was coated by a spin coating method. (UGECOAT 7655, manufactured by Daicel-Cytec Co., Ltd.), heat-dried on a hot plate at 60 ° C for 1 minute, and a protective layer is formed on the polarizing layer, thereby producing the present polarizing element (hereinafter, referred to as "the present polarizing element" G"). The results of the two-color ratio measurement of the produced polarizing element are shown in Table 1.

Example 10

On the protective layer of the present polarizing element F obtained in Example 8, a TAC (triethyl fluorene cellulose) film was bonded to each other via an adhesive layer formed of a pressure sensitive adhesive (PSA). The results of the measurement of the dichroic ratio of the structure obtained in this manner (hereinafter referred to as "the present polarizing element F + TAC") are shown in Table 1.

Example 11

On the protective layer of the present polarizing element G obtained in Example 9, a TAC (triethyl fluorene cellulose) film was bonded to each other via an adhesive layer formed of a pressure sensitive adhesive (PSA). The results of the measurement of the dichroic ratio of the structure obtained in this manner (hereinafter referred to as "the present polarizing element G + TAC") are shown in Table 1.

(※)

IPA: isopropanol

ETA: ethanol

PGMEA: propylene glycol mono methyl ether acetate

PGME: propylene glycol mono methyl ether

Evaluation example Durability test

The following change over time was tested as the durability test of the present polarizing element.

The present polarizing element obtained by the first to second embodiments and the structural body obtained by the embodiments 6 to 7, 10 (the present polarizing element A+TAC, the present polarizing element) B+TAC or this polarizing element F+TAC) is put into Hitachi thermostat (trade name: EC-15HHP, manufactured by Hitachi Air Conditioning Systems Co., Ltd.) [Condition: dry bulb temperature 60 ° C, humidity 90% RH, or 85 ° C, The humidity was 0%], and the absorbance after 100 hours passed was measured to determine the dichroic ratio. In this manner, the dichroic ratio was measured again after 100 hours, and the judgment was made at the following two levels: the case where the initial dichroic ratio and the passed dichromatic ratio did not substantially change was judged as "g" (good), The case of deterioration is judged as "b" (bad). The results are shown in Table 2.

2. Solvent resistance test

When the present polarizing element is used in a liquid crystal cell, that is, in the case of an In-cell liquid crystal display device, it is necessary to provide a PI (polyimide) alignment film on the protective layer of the polarizing element. When the PI alignment film is formed, a solution of NMP (N-Methyl-2-pyrrolidone, N-methyl-2-pyrrolidone) is often used. That is, the present polarizing element is required to have solvent resistance to NMP. Therefore, NMP was dropped on the surface of the protective layer, and after 5 minutes, it was wiped off to evaluate whether or not the protective layer was dissolved. The evaluation results were judged by the following two levels: the case where no dissolution by NMP was observed was judged as "g" (good), and the case where dissolution by NMP was observed was judged as "b" (bad). The results are shown in Table 3.

[Industrial availability]

The polarizing element of the present invention is extremely useful in the production of a liquid crystal display device, an (organic) EL display device, and a projection type liquid crystal display device.

1‧‧‧ polarizing element of the invention (this polarizing element)

2‧‧‧Transparent substrate

3‧‧‧Alignment layer

4‧‧‧ polarizing layer

5‧‧‧Matrix

6‧‧‧ dichroic pigment

7‧‧‧Protective layer

10‧‧‧Liquid crystal display device

11‧‧‧Anti-reflective film

12a, 12b‧‧‧ polarizing film

13a, 13b‧‧‧ phase difference layer

14a, 14b‧‧‧substrate

15‧‧‧Color filters

16‧‧‧Transparent electrode

17‧‧‧Liquid layer

18‧‧‧Interlayer insulating film

19‧‧‧Backlight unit

20‧‧‧Black matrix

21‧‧‧film transistor

22‧‧‧pixel electrode

23‧‧‧ spacers

24‧‧‧Liquid crystal display device

30‧‧‧EL display device

31‧‧‧Polarized components

32‧‧‧ phase difference layer

33‧‧‧Substrate

34‧‧‧Interlayer insulating film

35‧‧‧pixel electrode

36‧‧‧Lighting layer

37‧‧‧Cathode electrode

38‧‧‧Drying agent

39‧‧‧ Sealing cover

40‧‧‧film transistor

41‧‧‧ blocking wall

42‧‧‧film sealing film

44‧‧‧EL display device

111‧‧‧Light source

112‧‧‧1st lens array

112a‧‧ lens

113‧‧‧2nd lens array

114‧‧‧Polarized light conversion element

115‧‧‧Overlapping lens

121, 123, 132‧ ‧ dichroic mirror

122‧‧‧Mirror

140B, 140G, 140R‧‧‧ LCD panel

142, 143‧‧‧ polarizing film

150‧‧‧合光稜鏡

170‧‧‧Projection lens

180‧‧‧ screen

Fig. 1 is a schematic view showing a cross-sectional structure of a polarizing element of the present invention.

Fig. 2 is a schematic view showing a cross-sectional configuration of a liquid crystal display device using the polarizing element of the present invention.

3(A1) and (A2) are schematic diagrams showing the order of layers of the polarizing element of the present invention provided on a liquid crystal display device.

4(B1) and (B2) are schematic diagrams showing the order of layers of the polarizing element of the present invention provided on a liquid crystal display device.

Fig. 5 is a schematic view showing a cross-sectional configuration of a liquid crystal display device (in-cell form) using the polarizing element of the present invention.

Fig. 6 is a schematic view showing a cross-sectional configuration of an EL display device using the polarizing element of the present invention.

Fig. 7 is a schematic view showing a method of manufacturing an EL display device using the polarizing element of the present invention.

8(C1) and (C2) schematically show the arrangement on the EL display device. A schematic diagram of the layer sequence of the polarizing element of the present invention.

Fig. 9 is a schematic view showing a cross-sectional configuration of an EL display device using the polarizing element of the present invention.

Fig. 10 is a schematic view showing a projection type liquid crystal display device using the polarizing element of the present invention.

1‧‧‧ polarizing element of the invention (this polarizing element)

2‧‧‧Transparent substrate

3‧‧‧Alignment layer

4‧‧‧ polarizing layer

5‧‧‧Matrix

6‧‧‧ dichroic pigment

7‧‧‧Protective layer

Claims (17)

A polarizing element which is provided with an alignment layer, a polarizing layer and a protective layer on a transparent substrate, and the polarizing layer is manufactured by a manufacturing method comprising the following steps: comprising a polymerizable liquid crystal compound, two colors a composition of a dye, a polymerization initiator and a solvent to form a film; removing the solvent from the film; forming the stratified liquid crystal state of the polymerizable liquid crystal compound contained in the film from which the solvent has been removed; and polymerizing the above The liquid crystal compound is polymerized while maintaining the smectic liquid crystal state, and the polarizing layer is formed of a composition comprising a polymerizable liquid crystal composition having a display layer phase, a dichroic dye, a polymerization initiator, and a solvent, and the polarizing layer. In the above, the polymerizable liquid crystal composition of the display layer phase is horizontally aligned. The polarizing element of claim 1, wherein the polarizing layer is a polarizing layer that obtains a Bragg peak in an X-ray diffraction measurement. The polarizing element of claim 1 or 2, wherein the thickness of the polarizing layer is in the range of 0.5 to 3 μm. The polarizing element of claim 1 or 2, wherein the dichroic dye is an azo dye. The polarizing element according to claim 1 or 2, wherein the polymerizable liquid crystal compound contains two or more kinds of polymerizable smectic liquid crystal compounds. The polarizing element of claim 1 or 2, wherein the protective layer is comprised of A protective layer composition of a functional acrylate and a solvent is formed, and the solvent substantially comprises an alcohol solvent and/or an ether solvent. The polarizing element according to claim 1 or 2, wherein the protective layer is formed of a composition for forming a protective layer comprising a polymer or oligomer obtained by polymerizing a polyfunctional acrylate and water. The polarizing element according to claim 1 or 2, wherein the protective layer is formed of a composition for forming a protective layer comprising a water-soluble polymer and water. A liquid crystal display device comprising the polarizing element according to any one of claims 1 to 8. The liquid crystal display device of claim 9, wherein the polarizing element is disposed inside the liquid crystal cell. A circular polarizing plate provided with a quarter-wave plate on the protective layer of the polarizing element according to any one of claims 1 to 8. The circular polarizing plate of claim 11, wherein the quarter-wavelength plate has a wavelength plate having a characteristic that the in-plane retardation value with respect to visible light becomes smaller as the wavelength becomes shorter. An organic EL display device comprising the circular polarizing plate of claim 11 or 12, and an organic EL element. A method for producing a polarizing element, comprising: a step (1) of forming an alignment layer on a transparent substrate to form a laminate; and a step (2) of applying a polymerizable liquid crystal on the alignment layer of the laminate a composition of a compound, a dichroic dye, and a polymerization initiator to form a first coating film on the alignment layer; and a step (3) of forming the first coating layer formed by the above step (2) The film is dried under the condition that the polymerizable liquid crystal compound contained in the first coating film is not polymerized, thereby forming a first dry film, and the polymerizable liquid crystal in the first dried film After the compound forms a smectic liquid crystal state, the polymerizable liquid crystal compound is polymerized in the smectic liquid crystal state to form a polarizing layer, and the step (4) is performed by the above steps. (3) applying a protective film composition containing a polyfunctional acrylate and a solvent to the polarizing layer formed, and forming a second coating film on the polarizing layer, and containing the second coating film The polyfunctional acrylate is polymerized to form a protective layer from the second coating film. The method for producing a polarizing element according to claim 14, wherein the solvent contained in the protective film composition contains an alcohol solvent and/or an ether solvent. A method for producing a polarizing element, comprising: a step (1) of forming an alignment layer on a transparent substrate to form a laminate; and a step (2) of applying a polymerizable liquid crystal on the alignment layer of the laminate a composition of a compound, a dichroic dye, and a polymerization initiator to form a first coating film on the alignment layer; and a step (3) of forming the first coating layer formed by the above step (2) The film is dried under the condition that the polymerizable liquid crystal compound contained in the first coating film is not polymerized, thereby forming a first dry film, and the polymerizable liquid crystal in the first dried film After the compound forms a smectic liquid crystal state, the polymerizable liquid crystal compound is polymerized in the smectic liquid crystal state to form a polarizing layer, and the step (4) is performed by the above steps. (3) forming the above polarizing layer The composition for forming a protective layer containing a polymer or an oligomer obtained by polymerizing a polyfunctional acrylate and water is applied thereon, and a second coating film is formed on the polarizing layer, and the second coating film is formed. Drying, thereby forming a protective layer from the second coating film. A method for producing a polarizing element, comprising: a step (1) of forming an alignment layer on a transparent substrate to form a laminate: step (2), coating a polymerizable liquid crystal on the alignment layer of the laminate a composition of a compound, a dichroic dye, and a polymerization initiator to form a first coating film on the alignment layer; and a step (3) of forming the first coating layer formed by the above step (2) The film is dried under the condition that the polymerizable liquid crystal compound contained in the first coating film is not polymerized, thereby forming a first dry film, and the polymerizable liquid crystal in the first dried film After the compound forms a smectic liquid crystal state, the polymerizable liquid crystal compound is polymerized in the smectic liquid crystal state to form a polarizing layer, and the step (4) is performed by the above steps. (3) The protective layer forming composition containing a water-soluble polymer and water is applied onto the polarizing layer formed, and a second coating film is formed on the polarizing layer, and the second coating film is dried. Thereby, a protective layer is formed from the second coating film.