JP2005099065A - Polarizer, optical film and picture display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dyestuff system polarizer having high transmittance and the high degree of polarization, restraining the unevenness of transmittance in the case of black display and excellent in heat resistance. <P>SOLUTION: In the polarizer composed of film having structure where fine areas are dispersed in a matrix formed of light transmissive thermoplastic resin containing absorptive dichroic dyestuffs, the transmittance to linearly polarized light in a transmission direction is set to ≥80%, a haze value thereto is ≤10% and a haze value to linearly polarized light in an absorption direction is set to ≥50%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polarizer. The present invention also relates to a polarizing plate and an optical film using the polarizer. Further, the present invention relates to an image display device such as a polarizing plate, a liquid crystal display device using an optical film, an organic EL display device, a CRT, or a PDP.

  Liquid crystal display devices are rapidly marketed in watches, mobile phones, PDAs, notebook computers, personal computer monitors, DVD players, TVs, and the like. A liquid crystal display device visualizes a change in polarization state due to switching of liquid crystal, and a polarizer is used from the display principle. In particular, displays with higher brightness and higher contrast are required for applications such as TV, and light polarizers with higher brightness (high transmittance) and higher contrast (high polarization degree) have been developed and introduced. Yes. In particular, liquid crystal display devices that are assumed to be used outdoors in harsh environments such as mobile phones and PDAs, in-vehicle navigation systems, liquid crystal display devices for liquid crystal projectors, and the like are required to have extremely high heat resistance and reliability. .

  As a polarizer, for example, an iodine polarizer having a stretched structure obtained by adsorbing iodine to polyvinyl alcohol is widely used because it has a high transmittance and a high degree of polarization. However, in iodine-based polarizers, iodine compounds that function as a dichroic material formed in the stretching process are poor in thermal stability. For example, if a test that is left for a long time in an atmosphere of 100 ° C. assuming a dashboard in an automobile in midsummer, etc., the iodine compound is denatured and the dichroism is remarkably lowered, and the function as a polarizer is large. There was a problem of lowering. For this reason, dye-based polarizers using dichroic dyes in place of iodine compounds are used in fields requiring high heat reliability such as in-vehicle applications (see, for example, Patent Document 1).

  However, the dichroic dye has a lower absorption dichroic ratio than the iodine compound. Therefore, the dye-based polarizer is slightly inferior to the iodine-based polarizer in terms of characteristics. Further, when adsorbing a dye, uneven dyeing or uneven dispersion tends to occur. In particular, in a liquid crystal display device, there is a problem that when black display is performed, black is displayed in a mottled manner and the visibility is significantly reduced.

In order to solve this problem, a dye-based polarizer has been proposed in which the amount of dye adsorbed or added is increased so that the transmittance during black display is below the human eye's perception limit. However, this dye-based polarizer reduces the transmittance for white display as well as the transmittance for black display, and the display itself becomes dark. In addition, a method for manufacturing a dye-based polarizer that employs a stretching process that hardly causes unevenness has been proposed (see, for example, Patent Document 2). However, in this method, it is necessary to replace the process itself, which deteriorates productivity.
JP 62-123405 A JP-A-8-190015

  An object of the present invention is to provide a dye-based polarizer having high transmittance and high degree of polarization, which can suppress unevenness in transmittance during black display and has good heat resistance.

  Another object of the present invention is to provide a polarizing plate and an optical film using the polarizer. Furthermore, it aims at providing the image display apparatus using the said polarizer, a polarizing plate, and an optical film.

  As a result of intensive studies to solve the above problems, the present inventors have found that the object can be achieved by a polarizer shown below, and have completed the present invention.

That is, the present invention is a polarizer comprising a film having a structure in which minute regions are dispersed in a matrix formed of a translucent thermoplastic resin containing an absorbing dichroic dye,
The present invention relates to a polarizer having a transmittance of 80% or more for linearly polarized light in the transmission direction, a haze value of 10% or less, and a haze value of 50% or more for linearly polarized light in the absorption direction.

  The microregion of the polarizer is preferably formed of an oriented birefringent material. The birefringent material preferably exhibits liquid crystallinity at least at the time of alignment treatment.

  The polarizer of the present invention secures heat resistance reliability by using a dye-based polarizer formed of a light-transmitting thermoplastic resin and an absorbing dichroic dye as a matrix. In addition, minute regions are dispersed in the matrix. The minute region is preferably formed of an oriented birefringent material, and particularly the minute region is preferably formed of a material exhibiting liquid crystallinity. Thus, in addition to the function of absorption dichroism by the absorption dichroic dye, by combining the function of scattering anisotropy, the polarization performance is improved by the synergistic effect of the two functions, and the transmittance and polarization degree. A polarizer with good visibility is obtained.

  The polarizer preferably has a transmittance of 80% or more for linearly polarized light in the transmission direction, a haze value of 10% or less, and a haze value of 50% or more for linearly polarized light in the absorption direction.

  The dye-based polarizer of the present invention having the above-described transmittance and haze value has high transmittance and good visibility for linearly polarized light in the transmission direction, and strong light for linearly polarized light in the absorption direction. Has diffusivity. Therefore, it is possible to reduce the unevenness of the transmittance during black display with a high transmittance and a high degree of polarization without sacrificing other optical characteristics by a simple method.

  The polarizer of the present invention preferably has a transmittance as high as possible for linearly polarized light in the transmission direction, that is, linearly polarized light in a direction orthogonal to the maximum absorption direction of the absorbing dichroic dye, It is preferable to have a light transmittance of 80% or more when the light intensity of incident linearly polarized light is 100. The light transmittance is more preferably 85% or more, and more preferably 88% or more. Here, the light transmittance is a spectral transmittance at 550 nm measured using a spectrophotometer with an integrating sphere. Since about 8% to 10% is reflected by the air interface on the front and back surfaces of the polarizer, the ideal limit is 100% minus this surface reflection.

  Further, it is desirable that the polarizer does not scatter linearly polarized light in the transmission direction from the viewpoint of clarity of display image visibility. Therefore, the haze value for linearly polarized light in the transmission direction is preferably 10% or less. More preferably, it is 5% or less, More preferably, it is 3% or less. On the other hand, it is desirable that the polarizer linearly polarized light in the absorption direction, that is, the linearly polarized light in the maximum absorption direction of the absorbing dichroic dye is strongly scattered from the viewpoint of concealing unevenness due to local transmittance variation by scattering. Therefore, the haze value for linearly polarized light in the absorption direction is preferably 50% or more. More preferably, it is 60% or more, More preferably, it is 70% or more. The haze value is a value measured based on JIS K 7136 (Plastic—How to determine haze of transparent material).

  The optical characteristics are caused by the composite of the function of scattering anisotropy in addition to the function of absorption dichroism of the polarizer. The same is true for the scattering differences described in U.S. Pat. No. 2,213,902 and JP-A-9-274108 and JP-A-9-297204, which have the function of selectively scattering only linearly polarized light. It can also be achieved by superimposing the isotropic film and the dichroic absorption polarizer in an axial arrangement in which the scattering maximum axis and the absorption maximum axis are parallel to each other. However, it is necessary to separately form a scattering anisotropic film, and the alignment accuracy at the time of superimposing becomes a problem. The effect of increasing the optical path length cannot be expected, and it is difficult to achieve high transmission and high degree of polarization.

  In the polarizer, it is preferable that the birefringence of the minute region is 0.02 or more. As the material used for the minute region, a material having the birefringence is preferably used from the viewpoint of obtaining a larger anisotropic scattering function.

In the polarizer, the refractive index difference for each optical axis direction between the birefringent material forming a minute region and the translucent thermoplastic resin is as follows:
The refractive index difference (Δn ¹ ) in the axial direction showing the maximum value is 0.03 or more,
The refractive index difference (Δn ² ) in the ^two axial directions perpendicular to the Δn ¹ direction is preferably 50% or less of the Δn ¹ .

A straight line in the Δn ¹ direction as proposed in US Pat. No. 2,213,902 by controlling the refractive index difference (Δn ¹ ), (Δn ² ) in each optical axis direction within the above range. A scattering anisotropic film having a function of selectively scattering only polarized light can be obtained. That is, since the refractive index difference is large in the Δn ¹ direction, linearly polarized light is scattered, while in the Δn ² direction, the linearly polarized light can be transmitted because the refractive index difference is small. The refractive index difference (Δn ² ) in ^two axial directions orthogonal to the Δn ¹ direction is preferably equal.

In order to increase the scattering anisotropy, the refractive index difference (Δn ¹ ) in the Δn ¹ direction is 0.03 or more, preferably 0.05 or more, particularly preferably 0.10 or more. Further, the refractive index difference (Δn ² ) in two directions orthogonal to the Δn ¹ direction is preferably 50% or less, more preferably 30% or less of the Δn ¹ .

In the polarizer, the absorption dichroic dye is preferably such that the absorption axis of the material is oriented in the Δn ¹ direction.

Absorption dichroic dye in the matrix, by the absorption axis of the material is oriented to be parallel to the △ n ¹ direction to selectively absorb △ n ¹ direction of linearly polarized light which is scattered polarization direction be able to. As a result, the linearly polarized light component in the Δn ² direction of the incident light is transmitted without being scattered. On the other hand, the linearly polarized light component in the Δn ¹ direction is scattered and absorbed by the absorbing dichroic dye. Usually, absorption is determined by the absorption coefficient and thickness. Since the apparent thickness of the polarizer of the present invention is large due to scattering, the polarization component in the Δn ¹ direction is absorbed more than the state without scattering anisotropy. That is, a higher degree of polarization can be obtained with the same transmittance.

Hereinafter, an ideal model will be described in detail. In general, two main transmittances used in a linear polarizer (first main transmittance k ₁ (maximum transmittance azimuth = linear polarization transmittance in Δn ² direction), second main transmittance k ₂ (minimum direction of transmittance). = Δn ¹ direction linearly polarized light transmission)))

In a commercially available dye-based polarizer, if the absorption dichroic material is oriented in one direction, the parallel transmittance and the polarization degree are respectively
Parallel transmittance = 0.5 × ((k ₁ ) ² + (k ₂ ) ² ),
Degree of polarization = (k ₁ −k ₂ ) / (k ₁ + k ₂ )

On the other hand, in the polarizer of the present invention, it is assumed that the polarized light in the Δn ¹ direction is scattered and the average optical path length is α (> 1) times. The transmittances are represented by k ₁ and k ₂ ′ = 10 ^X (where x is αlogk ₂ ), respectively.

In other words, the parallel transmittance and polarization degree in this case are
Parallel transmittance = 0.5 × ((k ₁ ) ² + (k ₂ ′) ² ),
Degree of polarization = (k ₁ − (k ₂ ′) ² ) / ((k ₁ + (k ₂ ′) ² ))

For example, the same amount as an absorptive dichroic material used for a commercially available dye-based polarizer (parallel transmittance 0.321, polarization degree 0.90: k ₁ = 0.80, k ₂ = 0.04) Assuming that the polarizer of the present invention is made using the same material, when the α is doubled in the calculation, the parallel transmittance is 0.320 and the polarization degree is 0.996. If the degree of polarization is fixed at 0.90 and the concentration of the absorbing dichroic material is reduced, the parallel transmittance can be increased to 0.406.

  The above calculated value is a theoretical value, and of course, the function is somewhat degraded due to the effects of depolarization due to scattering, surface reflection, and backscattering. Therefore, in order to fully exhibit the above functions, it is better that the backscattering is small, and the ratio of the backscattering intensity to the incident light intensity is preferably 30% or less, and more preferably 20% or less.

  As the polarizer, a film produced by stretching can be suitably used.

In the polarizer, the micro area preferably has a length in the Δn ² direction of 0.05 to 500 μm.

In order to strongly scatter linearly polarized light having a vibration surface in the Δn ¹ direction among wavelengths in the visible light region, the dispersion-distributed microregion has a length in the Δn ² direction of 0.05 to 500 μm, It is preferably controlled so as to be 0.5 to 100 μm. If the length of the minute region in the Δn ² direction is too short compared to the wavelength, sufficient scattering will not occur. On the other hand, if the length of the micro area in the Δn ² direction is too long, there is a possibility that the film strength is lowered, or that the liquid crystalline material forming the micro area is not sufficiently aligned in the micro area.

  In the polarizer, a liquid crystalline thermoplastic resin in which a nematic phase or a smectic phase appears in a temperature range lower than the glass transition temperature of the light-transmitting thermoplastic resin is preferably used as the birefringent material forming the microregion. Used.

  In the polarizer, after the birefringent material forming the minute region is aligned with a liquid crystal monomer in which a nematic phase or a smectic phase state appears in a temperature region lower than the glass transition temperature of the light-transmitting thermoplastic resin. A polymerized product is preferably used.

  In the polarizer, the absorbing dichroic dye is preferably a dye having at least one absorption band having a dichroic ratio of 3 or more in the visible light wavelength region.

  As a scale for evaluating the dichroic ratio, for example, a homogeneously aligned liquid crystal cell is prepared using an appropriate liquid crystal material in which a dye is dissolved, and the absorption at the absorption maximum wavelength in the polarization absorption spectrum measured using the cell is measured. A dichroic ratio is used. In this evaluation method, for example, when E-7 manufactured by Merck is used as the standard liquid crystal, the dye used is a standard value of the dichroic ratio at the absorption wavelength of 3 or more, preferably 6 or more, and more preferably. 9 or more.

  The present invention also relates to a polarizing plate in which a transparent protective layer is provided on at least one surface of the polarizer.

  The present invention also relates to an optical film, wherein at least one of the polarizer and the polarizing plate is laminated.

  Furthermore, this invention relates to the image display apparatus characterized by using the said polarizer, the said polarizing plate, or the said optical film.

  Hereinafter, the polarizer of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual top view of a polarizer of the present invention, in which a film is formed of a translucent thermoplastic resin 1 containing an absorbing dichroic dye 2, and the microregion 3 is formed using the film as a matrix. Has a distributed structure. As described above, in the polarizer of the present invention, the absorbing dichroic dye 2 is present in the translucent thermoplastic resin 1 that forms a film as a matrix. It can also be present to the extent that it does not optically affect.

FIG. 1 shows an example in which the absorbing dichroic dye 2 is oriented in the axial direction (Δn ¹ direction) in which the difference in refractive index between the minute region 3 and the translucent thermoplastic resin 1 is maximum. It is. In the minute region 3, the polarization component in the Δn ¹ direction is scattered. In FIG. 1, the Δn ¹ direction in ^one direction in the film plane is an absorption axis. In the film plane △ n ¹ perpendicular to the direction △ n ² direction is a transmission axis. Incidentally, another △ n ² direction perpendicular to △ n ¹ direction is the thickness direction.

  As the translucent thermoplastic resin 1, those having translucency in the visible light region and capable of dispersing and adsorbing the absorbing dichroic dye can be used without particular limitation. For example, polyvinyl alcohol or its derivative conventionally used for a polarizer is mentioned. Derivatives of polyvinyl alcohol include polyvinyl formal, polyvinyl acetal and the like, olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, alkyl esters thereof, acrylamide and the like. can give.

  Examples of the translucent thermoplastic resin 1 include polyester resins such as polyethylene terephthalate and polyethylene naphthalate; styrene resins such as polystyrene and acrylonitrile / styrene copolymer (AS resin); polyethylene, polypropylene, cyclo or norbornene. Examples thereof include polyolefins having a structure and olefin resins such as ethylene / propylene copolymers. Furthermore, vinyl chloride resin, cellulose resin, acrylic resin, amide resin, imide resin, sulfone polymer, polyether sulfone resin, polyether ether ketone resin polymer, polyphenylene sulfide resin, vinylidene chloride Resin, vinyl butyral resin, arylate resin, polyoxymethylene resin, silicone resin, urethane resin and the like. These can be used alone or in combination of two or more. In addition, a cured product of a thermosetting or ultraviolet curable resin such as phenol, melamine, acrylic, urethane, acrylurethane, epoxy, or silicone can also be used.

The translucent thermoplastic resin may have an isotropic property that hardly causes orientation birefringence due to molding distortion or the like, or may have anisotropy that easily causes orientation birefringence. The light-transmitting thermoplastic resin preferably has a glass transition temperature of 110 ° C. or higher, more preferably 115 ° C. or higher, particularly 120 ° C. or higher from the viewpoint of heat resistance and workability. Moreover, what has a weighted deflection temperature of 80 degreeC or more is preferable. In accordance with JIS K 7207, the load deflection temperature was increased by heating the heat transfer medium at 2 ° C / min while applying a bending stress of 181.4 N / cm ² to a test piece with a height of 10 mm in the heating bath. This is the temperature of the heat transfer medium when the deflection amount of the piece reaches 0.32 mm.

  The material forming the microregion 3 is not particularly limited as to whether it is isotropic or birefringent, but a birefringent material is preferable. As the birefringent material, a material exhibiting liquid crystallinity at the time of alignment treatment (hereinafter referred to as a liquid crystalline material) is preferably used. That is, as long as the liquid crystalline material exhibits liquid crystallinity at the time of the alignment treatment, the formed microregion 3 may exhibit liquid crystallinity or may lose liquid crystallinity.

  The material for forming the minute region 3 may be any of nematic liquid crystal property, smectic liquid crystal property, cholesteric liquid crystal property, or lyotropic liquid crystal material. The birefringent material may be a liquid crystalline thermoplastic resin, or may be formed by polymerization of a liquid crystalline monomer. When the liquid crystalline material is a liquid crystalline thermoplastic resin, those having a high glass transition temperature are preferable from the viewpoint of the heat resistance of the finally obtained structure. It is preferable to use a glass that is at least at room temperature. The liquid crystalline thermoplastic resin is usually oriented by heating, cooled and fixed to form the microregion 3 while maintaining liquid crystallinity. The liquid crystalline monomer can form the microregion 3 in a state where it is fixed by polymerization, cross-linking or the like after blending, but the liquid crystallinity is lost in the microregion 3 formed. As the liquid crystalline material, a liquid crystalline thermoplastic resin that maintains liquid crystallinity even in the minute region 3 is preferable.

  As the liquid crystalline thermoplastic resin, polymers of various skeletons of main chain type, side chain type, or a composite type thereof can be used without particular limitation. Examples of the main chain type liquid crystal polymer include condensation polymers having a structure in which mesogenic groups composed of aromatic units and the like are bonded, for example, polymers such as polyester, polyamide, polycarbonate, and polyesterimide. Examples of the aromatic unit that becomes a mesogenic group include phenyl, biphenyl, and naphthalene types, and these aromatic units have substituents such as a cyano group, an alkyl group, an alkoxy group, and a halogen group. May be.

  Side chain type liquid crystal polymers include polyacrylate, polymethacrylate, poly-α-halo-acrylate, poly-α-halo-cyanoacrylate, polyacrylamide, polysiloxane, and polymalonate main chains. Examples of the skeleton include those having a mesogenic group composed of a cyclic unit or the like in the side chain. Examples of the cyclic unit serving as a mesogenic group include biphenyl, phenylbenzoate, phenylcyclohexane, azoxybenzene, azomethine, azobenzene, phenylpyrimidine, diphenylacetylene, diphenylbenzoate, and bicyclohexane. Cyclohexylbenzene, terphenyl and the like. In addition, the terminal of these cyclic units may have substituents, such as a cyano group, an alkyl group, an alkenyl group, an alkoxy group, a halogen group, a haloalkyl group, a haloalkoxy group, a haloalkenyl group, for example. Moreover, what has a halogen group can be used for the phenyl group of a mesogenic group.

  Further, the mesogenic group of any liquid crystal polymer may be bonded via a spacer portion that imparts flexibility. Examples of the spacer part include a polymethylene chain and a polyoxymethylene chain. The number of repeating structural units forming the spacer portion is appropriately determined depending on the chemical structure of the mesogenic portion, but the repeating unit of the polymethylene chain is 0 to 20, preferably 2 to 12, and the repeating unit of the polyoxymethylene chain is 0 to 0. 10, preferably 1-3.

  The liquid crystalline thermoplastic resin preferably has a glass transition temperature of 50 ° C. or higher, more preferably 80 ° C. or higher. Further, those having a weight average molecular weight of about 2,000 to 100,000 are preferred.

  Examples of the liquid crystalline monomer include those having a polymerizable functional group such as an acryloyl group or a methacryloyl group at the terminal, and a mesogenic group composed of the cyclic unit or the like and a spacer portion. In addition, as a polymerizable functional group, one having two or more acryloyl groups, methacryloyl groups and the like can be used to introduce a crosslinked structure to improve durability.

  The material for forming the minute region 3 is not limited to the liquid crystalline material, and a non-liquid crystalline resin can be used as long as the material is different from the matrix material. Examples of the resin include polyvinyl alcohol and derivatives thereof, polyolefin, polyarylate, polymethacrylate, polyacrylamide, polyethylene terephthalate, and acrylic styrene copolymer. Further, as a material for forming the minute region 3, particles having no birefringence can be used. Examples of the fine particles include resins such as polyacrylate and acrylic styrene copolymer. The size of the fine particles is not particularly limited, but those having a particle size of 0.05 to 500 μm, preferably 0.5 to 100 μm are used. The material for forming the minute region 3 is preferably the liquid crystalline material, but the liquid crystalline material can be mixed with a non-liquid crystalline material. Furthermore, a non-liquid crystalline material can be used alone as a material for forming the minute region 3.

  As the absorbing dichroic dye, those having heat resistance and those which do not lose dichroism due to decomposition or alteration are preferably used even when the liquid crystalline material of the birefringent material is heated and aligned. As described above, the absorbing dichroic dye is preferably a dye having at least one absorption band having a dichroic ratio of 3 or more in the visible light wavelength region. Examples of the dye having such a high dichroic ratio include azo dyes, perylene dyes and anthraquinone dyes preferably used for dye polarizers. These dyes can be used as mixed dyes. These dyes are detailed in, for example, JP-A-54-76171.

  In the case of forming a color polarizer, a dye having an absorption wavelength corresponding to the characteristics can be used. Further, when forming a neutral gray polarizer, two or more kinds of dyes are appropriately mixed and used so that absorption occurs in the entire visible light region.

  The polarizer of the present invention produces a film in which a matrix is formed from a light-transmitting thermoplastic resin 1 containing an absorbing dichroic dye 2, and a microregion 3 (for example, a liquid crystalline material is formed in the matrix. The oriented birefringent material) is dispersed.

The obtained polarizer is controlled so that the transmittance for linearly polarized light in the transmission direction is 80% or more, the haze value is 10% or less, and the haze value for linearly polarized light in the absorption direction is 50% or more. Further, in the film, the △ n ¹ direction refractive index difference ^{(△ n 1), △ n} 2 direction of the refractive index difference (△ n ²⁾ is preferably controlled to be within the above range.

The manufacturing process of the polarizer of the present invention is not particularly limited.
(1) The case where a liquid crystal material is used as a material for a micro region (hereinafter, a liquid crystal material is used as a material for the micro region) will be described as a representative example. A step of producing a mixed solution in which the material is dispersed)
(2) forming a film of the mixed solution of (1),
(3) A step of orienting (stretching) the film obtained in (2) above,
(4) A step of dispersing (dying) an absorbing dichroic dye in the light-transmitting thermoplastic resin serving as the matrix;
It is obtained by applying. Note that the order of the steps (1) to (4) can be determined as appropriate.

  In the step (1), first, a mixed solution is prepared in which a liquid crystalline material that becomes a micro region is dispersed in a light-transmitting thermoplastic resin that forms a matrix. A method for preparing the mixed solution is not particularly limited, and examples thereof include a method using a phase separation phenomenon between the matrix component (translucent thermoplastic resin) and a liquid crystal material. For example, as a liquid crystalline material, a material that is not compatible with the matrix component is selected, and a solution of the material that forms the liquid crystalline material is dispersed in an aqueous solution of the matrix component through a dispersant such as a surfactant. . In the preparation of the mixed solution, a dispersant may not be added depending on a combination of a light-transmitting material forming a matrix and a liquid crystal material forming a micro region. The amount of the liquid crystalline material to be dispersed in the matrix is not particularly limited, but 0.01 to 100 parts by weight, preferably 0.1 to 10 parts by weight of the liquid crystalline material with respect to 100 parts by weight of the light-transmitting thermoplastic resin. Parts by weight. The liquid crystalline material is used in a solvent or without being dissolved. Examples of the solvent include water, toluene, xylene, hexane, cyclohexane, dichloromethane, trichloromethane, dichloroethane, trichloroethane, tetrachloroethane, trichloroethylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, tetrahydrofuran, and ethyl acetate. . The solvent of the matrix component and the solvent of the liquid crystal material may be the same or different.

  In the step (2), in order to reduce foaming in the drying step after film formation, a solvent for dissolving the liquid crystalline material forming the microregion is not used in the preparation of the mixed solution in the step (1). Is preferred. For example, when a solvent is not used, a liquid crystal material is directly added to an aqueous solution of a translucent material that forms a matrix, and the liquid crystal material is heated and dispersed above the liquid crystal temperature range in order to disperse the liquid crystal material in a smaller and uniform manner. The method etc. are mention | raise | lifted.

  In addition, in a matrix component solution, a liquid crystal material solution, or a mixed solution, a dispersant, a surfactant, an ultraviolet absorber, a flame retardant, an antioxidant, a plasticizer, a release agent, a lubricant, a colorant, etc. These various additives can be contained within a range not impairing the object of the present invention.

In the step (2) of forming the mixed solution into a film, the mixed solution is heated and dried, and the solvent is removed to produce a film in which micro regions are dispersed in the matrix. As a film forming method, various methods such as a casting method, an extrusion molding method, an injection molding method, a roll molding method, and a casting method can be employed. In forming the film, the size of the minute region in the film is finally controlled to be 0.05 to 500 μm in the Δn ¹ direction. By adjusting the viscosity of the mixed solution, the selection and combination of the solvent of the mixed solution, the dispersant, the thermal process (cooling rate) of the mixed solvent, and the drying rate, the size and dispersibility of the microregion can be controlled. For example, a mixed solution of a high-viscosity light-transmitting thermoplastic resin that forms a matrix and a high-viscosity thermoplastic resin and a liquid crystalline material that forms a fine region is dispersed with a stirrer such as a homomixer while heating to a temperature above the liquid crystal temperature range. By doing so, it is possible to disperse the microscopic area smaller.

  The step (3) of orienting the film can be performed by stretching the film. Stretching includes uniaxial stretching, biaxial stretching, oblique stretching, etc., but uniaxial stretching is usually performed. The stretching method may be dry stretching in air, or may be wet stretching in an aqueous bath when the translucent thermoplastic resin is water-soluble such as polyvinyl alcohol. When wet stretching is employed, an additive (boron compound such as boric acid) can be appropriately added to the aqueous bath. Although the draw ratio is not particularly limited, it is usually preferably about 2 to 10 times.

  By such stretching, the absorbing dichroic dye can be oriented in the stretching axis direction. In addition, the liquid crystalline material that becomes a birefringent material in the minute region is oriented in the stretching direction in the minute region by the above stretching, and exhibits birefringence.

  It is desirable that the minute region is deformed according to stretching. When the microregion is a non-liquid crystalline material, the stretching temperature is close to the glass transition temperature of the resin, and when the microregion is a liquid crystalline material, the liquid crystalline material is in a liquid crystal state such as a nematic phase or a smectic phase or isotropic phase at the stretching temperature. It is desirable to select the temperature at which the condition is reached. If the orientation is insufficient at the time of stretching, a step such as a heat orientation treatment may be separately added.

  In addition to the stretching described above, an external field such as an electric field or a magnetic field may be used for the orientation of the liquid crystalline material. Alternatively, a liquid-reactive material such as azobenzene mixed with a photoreactive substance or a liquid-reactive material into which a photoreactive group such as a cinnamoyl group is introduced may be aligned by an alignment treatment such as light irradiation. . Furthermore, the stretching treatment and the orientation treatment described above can be used in combination. In the case where the liquid crystalline material is a liquid crystalline thermoplastic resin, the orientation is fixed and stabilized by being oriented at the time of stretching and then cooled to room temperature. The liquid crystalline monomer does not necessarily need to be cured because the desired optical properties are exhibited as long as it is oriented. However, liquid crystalline monomers having a low isotropic transition temperature are in an isotropic state when a little temperature is applied. In this case, the anisotropic scattering is eliminated and the polarization performance is not bad. In such a case, it is preferable to cure. In addition, many liquid crystalline monomers crystallize when left at room temperature. In this case, anisotropic scattering is eliminated, and conversely the polarization performance is not bad. Therefore, it is preferable to cure even in such a case. From this point of view, it is preferable to cure the liquid crystalline monomer in order for the alignment state to exist stably under any conditions. Curing of the liquid crystalline monomer is, for example, mixed with a photopolymerization initiator and dispersed in a solution of a matrix component, and after alignment, ultraviolet rays at any timing (before or after dyeing with an absorbing dichroic dye) Etc. are cured by irradiation, and the orientation is stabilized. Desirably, it is before dyeing with an absorptive dichroic dye.

  The step (4) of dispersing the absorbing dichroic dye in the translucent thermoplastic resin serving as the matrix generally includes a method of immersing the film in an aqueous bath in which the absorbing dichroic dye is dissolved. . The timing of immersion may be before or after the stretching step (3).

  The ratio of the absorbing dichroic dye in the obtained polarizer is not particularly limited, but the ratio of the light-transmitting thermoplastic resin and the absorbing dichroic dye is absorbed with respect to 100 parts by weight of the light-transmitting thermoplastic resin. It is preferable to control the dichroic dye to be about 0.01 to 100 parts by weight, more preferably 0.05 to 50 parts by weight.

  In addition, the absorbing dichroic dye used for dyeing and boric acid used for crosslinking are mixed in the step (1) instead of the method of penetrating into the film by immersing the film in an aqueous solution as described above. It is also possible to employ a method of adding any kind and amount before or after preparing the solution and before forming the film in the step (2). Moreover, you may use both methods together. However, in the step (3), when it is necessary to increase the temperature at the time of stretching or the like (for example, 80 ° C. or more) and the absorbing dichroic dye deteriorates at the temperature, the absorbing dichroism The step (4) of dispersing and dyeing the dye is preferably performed after the step (3).

  Mixing of the absorbing dichroic dye and the translucent thermoplastic resin before film formation is performed, for example, by a conventional method. For example, the absorption dichroic dye and the translucent thermoplastic resin are mixed by dissolving them in the same solvent. Usually, a dichroic dye and a translucent thermoplastic resin that are dissolved in the same solvent are appropriately selected. Examples of the solvent used for mixing the absorbing dichroic dye and the translucent thermoplastic resin include water, toluene, xylene, hexane, cyclohexane, dichloromethane, trichloromethane, dichloroethane, trichloroethane, tetrachloroethane, trichloroethylene, methyl ethyl ketone, and methyl isobutyl. Ketone, cyclohexanone, cyclopentanone, tetrahydrofuran, ethyl acetate and the like. In addition, when using water-soluble things, such as polyvinyl alcohol, as a translucent thermoplastic resin, water is used suitably as a solvent. The concentration of a solution in which the absorbing dichroic dye and the translucent thermoplastic resin are dissolved in a solvent is usually preferably adjusted to about 1 to 50% by weight.

  As mentioned above, when the absorbing dichroic dye is premixed with the light-transmitting thermoplastic resin and the film before stretching is dyed, the absorbing dichroic dye is used at the heating temperature during stretching. Those that do not decompose or deteriorate are used.

  In producing the polarizer, in addition to the steps (1) to (4), a step (5) for various purposes can be performed. Examples of the step (5) include a step of swelling the film by immersing the film in a water bath mainly for the purpose of improving the dyeing efficiency of the film. Moreover, the process etc. which are immersed in the water bath which melt | dissolved arbitrary additives are mention | raise | lifted. A step of immersing the film in an aqueous solution containing additives such as boric acid and borax is mainly used for the purpose of crosslinking the water-soluble resin (matrix).

  Step (3) in which the film is oriented (stretched) and stretched, step (4) in which the absorption dichroic dye is dispersedly dyed in the matrix resin, and step (5) are performed at least once in steps (3) and (4). As long as it is, the number of steps, the order, and the conditions (bath temperature, immersion time, etc.) can be arbitrarily selected, and each step may be performed separately or a plurality of steps may be performed simultaneously. For example, you may perform the bridge | crosslinking process and extending process (3) of a process (5) simultaneously.

  The film subjected to the above treatment is desirably dried under appropriate conditions. Drying is performed according to a conventional method.

  The thickness of the obtained polarizer (film) is not particularly limited, but is usually 1 μm to 3 mm, preferably 5 μm to 1 mm, and more preferably 10 to 500 μm.

The polarizer thus obtained usually has no particular relationship between the refractive index of the birefringent material forming the microregion and the refractive index of the matrix resin in the stretching direction, and the stretching direction is in the Δn ¹ direction. ing. Two vertical directions perpendicular to the stretching axis are Δn ² directions. Further, the absorption dichroic dye has a stretching direction in a direction showing maximum absorption, and is a polarizer in which the effect of absorption + scattering is expressed to the maximum.

  Since the polarizer obtained by the present invention has the same function as an existing absorption polarizing plate, it can be used without any change to various application fields using the absorption polarizing plate.

  The obtained polarizer can be made into a polarizing plate provided with a transparent protective layer on at least one surface thereof according to a conventional method. The transparent protective layer can be provided as a polymer-coated layer or a film laminate layer. As the transparent polymer or film material for forming the transparent protective layer, an appropriate transparent material can be used, but a material excellent in transparency, mechanical strength, thermal stability, moisture barrier property and the like is preferably used. Examples of the material for forming the transparent protective layer include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as cellulose diacetate and cellulose triacetate, acrylic polymers such as polymethyl methacrylate, polystyrene, acrylonitrile, Examples thereof include styrene polymers such as styrene copolymers (AS resins), polycarbonate polymers, and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like are also examples of the polymer that forms the transparent protective layer.

  Moreover, the polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and (B) a substitution in the side chain And / or a resin composition containing an unsubstituted phenyl and a thermoplastic resin having a nitrile group. A specific example is a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of the resin composition or the like can be used.

  The transparent protective layer that can be particularly preferably used in terms of polarization characteristics and durability is a triacetyl cellulose film whose surface is saponified with alkali or the like. The thickness of the transparent protective layer is arbitrary, but is generally 500 μm or less, more preferably 1 to 300 μm, and particularly preferably 5 to 300 μm for the purpose of reducing the thickness of the polarizing plate. In addition, when providing a transparent protective layer on both sides of a polarizer, the transparent protective film which consists of a polymer etc. which are different in the front and back can be used.

  Moreover, it is preferable that a transparent protective film has as little color as possible. Therefore, Rth = [(nx + ny) / 2−nz] · d (where nx and ny are the main refractive index in the plane of the film, nz is the refractive index in the film thickness direction, and d is the film thickness). A protective film having a retardation value in the film thickness direction of −90 nm to +75 nm is preferably used. By using a film having a thickness direction retardation value (Rth) of −90 nm to +75 nm, the coloring (optical coloring) of the polarizing plate caused by the protective film can be almost eliminated. The thickness direction retardation value (Rth) is more preferably −80 nm to +60 nm, and particularly preferably −70 nm to +45 nm.

  The surface of the transparent protective film to which the polarizer is not adhered may be subjected to a hard coat layer, an antireflection treatment, an antisticking treatment, or a treatment for diffusion or antiglare.

  The hard coat treatment is applied for the purpose of preventing scratches on the surface of the polarizing plate. For example, a transparent protective film with a cured film excellent in hardness, sliding properties, etc. by an appropriate ultraviolet curable resin such as acrylic or silicone is used. It can be formed by a method of adding to the surface of the film. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the conventional art. Further, the anti-sticking treatment is performed for the purpose of preventing adhesion with an adjacent layer.

  The anti-glare treatment is applied for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by a sandblasting method or an embossing method. It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a blending method of transparent particles. The fine particles to be included in the formation of the surface fine concavo-convex structure are, for example, conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide or the like having an average particle size of 0.5 to 50 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles composed of a crosslinked or uncrosslinked polymer, and the like are used. When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

  The antireflection layer, antisticking layer, diffusing layer, antiglare layer and the like can be provided on the transparent protective film itself, or can be provided separately from the transparent protective layer as an optical layer.

  An adhesive is used for the adhesion treatment between the polarizer and the transparent protective film. Examples of the adhesive include isocyanate adhesives, polyvinyl alcohol adhesives, gelatin adhesives, vinyl latexes, and water-based polyesters. The said adhesive agent is normally used as an adhesive agent which consists of aqueous solution, and contains 0.5 to 60 weight% of solid content normally.

  The polarizing plate of the present invention is produced by bonding the transparent protective film and the polarizer using the adhesive. The adhesive may be applied to either the transparent protective film or the polarizer, or to both. After the bonding, a drying process is performed to form an adhesive layer composed of a coating dry layer. Bonding of a polarizer and a transparent protective film can be performed with a roll laminator or the like. The thickness of the adhesive layer is not particularly limited, but is usually about 0.1 to 5 μm.

  The polarizing plate of the present invention can be used as an optical film laminated with another optical layer in practical use. The optical layer is not particularly limited. For example, for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a phase difference plate (including wavelength plates such as 1/2 and 1/4), and a viewing angle compensation film. One or more optical layers that may be used can be used. In particular, a reflective polarizing plate or a semi-transmissive polarizing plate in which a polarizing plate or a semi-transmissive reflecting plate is further laminated on the polarizing plate of the present invention, an elliptical polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on the polarizing plate. A wide viewing angle polarizing plate obtained by further laminating a viewing angle compensation film on a plate or a polarizing plate, or a polarizing plate obtained by further laminating a brightness enhancement film on the polarizing plate is preferable.

  A reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device or the like that reflects incident light from the viewing side (display side). Such a light source can be omitted, and the liquid crystal display device can be easily thinned. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary.

  Specific examples of the reflective polarizing plate include those in which a reflective layer is formed by attaching a foil or a vapor deposition film made of a reflective metal such as aluminum on one side of a transparent protective film matted as necessary. Moreover, the transparent protective film contains fine particles so as to have a surface fine concavo-convex structure and a reflective layer having a fine concavo-convex structure thereon. The reflective layer having the fine concavo-convex structure has an advantage that incident light is diffused by irregular reflection to prevent directivity and glaring appearance and to suppress unevenness in brightness and darkness. The transparent protective film containing fine particles also has an advantage that incident light and its reflected light are diffused when passing through it, and light and dark unevenness can be further suppressed. The reflective layer of the fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective film is formed by transparent the metal by an appropriate method such as a vapor deposition method such as a vacuum vapor deposition method, an ion plating method, a sputtering method, or a plating method. It can be performed by a method of directly attaching to the surface of the protective layer.

  Instead of the method of directly applying the reflecting plate to the transparent protective film of the polarizing plate, the reflecting plate can be used as a reflecting sheet provided with a reflecting layer on an appropriate film according to the transparent film. Since the reflective layer is usually made of metal, the usage form in which the reflective surface is covered with a transparent protective film, a polarizing plate or the like is used to prevent the reflectance from being lowered due to oxidation, and thus to maintain the initial reflectance for a long time. In addition, it is more preferable to avoid a separate attachment of the protective layer.

  The semi-transmissive polarizing plate can be obtained by using a semi-transmissive reflective layer such as a half mirror that reflects and transmits light with the reflective layer. A transflective polarizing plate is usually provided on the back side of a liquid crystal cell, and displays an image by reflecting incident light from the viewing side (display side) when a liquid crystal display device is used in a relatively bright atmosphere. In a relatively dark atmosphere, a liquid crystal display device or the like that displays an image using a built-in light source such as a backlight built in the back side of the transflective polarizing plate can be formed. In other words, the transflective polarizing plate is useful for forming a liquid crystal display device of a type that can save energy of using a light source such as a backlight in a bright atmosphere and can be used with a built-in light source even in a relatively dark atmosphere. It is.

  An elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate will be described. A phase difference plate or the like is used when changing linearly polarized light to elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light to linearly polarized light, or changing the polarization direction of linearly polarized light. In particular, a so-called 1/4 wavelength plate (also referred to as a λ / 4 plate) is used as a retardation plate that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. A 1/2 wave plate (also referred to as a λ / 2 plate) is usually used to change the polarization direction of linearly polarized light.

  The elliptically polarizing plate is effectively used for black and white display without the above color by compensating (preventing) the coloration (blue or yellow) generated by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device. It is done. Further, the one in which the three-dimensional refractive index is controlled is preferable because it can compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which an image is displayed in color, and also has an antireflection function. Specific examples of the retardation plate include a birefringent film obtained by stretching a film made of an appropriate polymer such as polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polypropylene, other polyolefins, polyarylate, and polyamide. And an alignment film of a liquid crystal polymer, and a liquid crystal polymer alignment layer supported by a film. The retardation plate may have an appropriate retardation according to the purpose of use, such as those for the purpose of compensating for various wavelength plates or birefringence of the liquid crystal layer, viewing angle, and the like. What laminated | stacked the phase difference plate and controlled optical characteristics, such as phase difference, etc. may be used.

  The elliptical polarizing plate and the reflective elliptical polarizing plate are obtained by laminating a polarizing plate or a reflective polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate or the like can also be formed by sequentially laminating them sequentially in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflective) polarizing plate and a retardation plate. An optical film such as a polarizing plate has an advantage that it can improve the production efficiency of a liquid crystal display device and the like because of excellent quality stability and lamination workability.

  The viewing angle compensation film is a film for widening the viewing angle so that an image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly oblique direction rather than perpendicular to the screen. As such a viewing angle compensation phase difference plate, for example, a retardation film, an alignment film such as a liquid crystal polymer, or an alignment layer such as a liquid crystal polymer supported on a transparent substrate is used. A normal retardation plate uses a birefringent polymer film uniaxially stretched in the plane direction, whereas a retardation plate used as a viewing angle compensation film stretches biaxially in the plane direction. Birefringent polymer film, biaxially stretched film such as polymer with birefringence with a controlled refractive index in the thickness direction that is uniaxially stretched in the plane direction and stretched in the thickness direction, etc. Used. Examples of the inclined alignment film include a film obtained by bonding a heat shrink film to a polymer film and stretching or / and shrinking the polymer film under the action of the contraction force by heating, and a film obtained by obliquely aligning a liquid crystal polymer. Can be mentioned. The raw material polymer for the phase difference plate is the same as the polymer described in the previous phase difference plate, preventing coloration due to a change in the viewing angle based on the phase difference by the liquid crystal cell and expanding the viewing angle for good visual recognition. An appropriate one for the purpose can be used.

  Also, from the viewpoint of achieving a wide viewing angle with good visibility, an optically compensated phase difference in which a liquid crystal polymer alignment layer, in particular an optically anisotropic layer composed of a discotic liquid crystal polymer gradient alignment layer, is supported by a triacetylcellulose film. A plate can be preferably used.

  A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually provided on the back side of a liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects light without transmitting the light other than the predetermined polarization state. The The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer or the like provided behind the brightness enhancement film and re-incident on the brightness enhancement film, and part or all of the light is transmitted as light having a predetermined polarization state. Luminance can be improved by increasing the amount of light transmitted through the enhancement film and increasing the amount of light that can be used for liquid crystal display image display or the like by supplying polarized light that is difficult to be absorbed by the polarizer. That is, when light is incident through the polarizer from the back side of the liquid crystal cell without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is almost polarized. It is absorbed by the polarizer and does not pass through the polarizer. That is, although depending on the characteristics of the polarizer used, approximately 50% of the light is absorbed by the polarizer, and the amount of light that can be used for liquid crystal image display or the like is reduced accordingly, resulting in a dark image. The brightness enhancement film allows light having a polarization direction that is absorbed by the polarizer to be reflected once by the brightness enhancement film without being incident on the polarizer, and further inverted through a reflective layer provided on the rear side thereof. Repeatedly re-enter the brightness enhancement film, and the brightness enhancement film transmits only polarized light whose polarization direction is such that the polarization direction of light reflected and inverted between the two can pass through the polarizer. Therefore, light such as a backlight can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.

  A diffusion plate may be provided between the brightness enhancement film and the reflective layer. The polarized light reflected by the brightness enhancement film is directed to the reflective layer or the like, but the installed diffuser plate uniformly diffuses the light passing therethrough and simultaneously cancels the polarized state and becomes a non-polarized state. That is, the diffuser plate returns the polarized light to the original natural light state. The light in the non-polarized state, that is, the natural light state is directed toward the reflection layer and the like, reflected through the reflection layer and the like, and again passes through the diffusion plate and reenters the brightness enhancement film. Thus, while maintaining the brightness of the display screen by providing a diffuser plate that returns polarized light to the original natural light state between the brightness enhancement film and the reflective layer, etc., the brightness unevenness of the display screen is reduced at the same time, A uniform and bright screen can be provided. By providing such a diffuser plate, it is considered that the first incident light has a moderate increase in the number of repetitions of reflection, and in combination with the diffusion function of the diffuser plate, a uniform bright display screen can be provided.

  The brightness enhancement film has a characteristic of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayer thin film of dielectric material or a multilayer laminate of thin film films having different refractive index anisotropies. Such as an alignment film of a cholesteric liquid crystal polymer or an alignment liquid crystal layer supported on a film substrate, which reflects either left-handed or right-handed circularly polarized light and transmits other light. Appropriate things such as a thing can be used.

  Therefore, in the brightness enhancement film of the type that transmits linearly polarized light having the predetermined polarization axis as described above, the transmitted light is incident on the polarizing plate with the polarization axis aligned as it is, thereby efficiently transmitting while suppressing absorption loss due to the polarizing plate. Can be made. On the other hand, in a brightness enhancement film of a type that emits circularly polarized light such as a cholesteric liquid crystal layer, it can be directly incident on a polarizer. However, from the viewpoint of suppressing absorption loss, the circularly polarized light is linearly polarized through a retardation plate. It is preferable to make it enter into a polarizing plate. Note that circularly polarized light can be converted to linearly polarized light by using a quarter wave plate as the retardation plate.

  A retardation plate that functions as a quarter-wave plate in a wide wavelength range such as a visible light region exhibits, for example, a retardation layer that functions as a quarter-wave plate for light-color light having a wavelength of 550 nm and other retardation characteristics. It can be obtained by a method of superposing a retardation layer, for example, a retardation layer functioning as a half-wave plate. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may be composed of one or more retardation layers.

  In addition, the cholesteric liquid crystal layer can also be obtained by reflecting circularly polarized light in a wide wavelength range such as a visible light region by combining two or more layers having different reflection wavelengths and having an overlapping structure. Based on this, transmitted circularly polarized light in a wide wavelength range can be obtained.

  Further, the polarizing plate may be formed by laminating a polarizing plate and two or more optical layers as in the above-described polarization separation type polarizing plate. Therefore, a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above-mentioned reflective polarizing plate or transflective polarizing plate and a retardation plate are combined may be used.

  An optical film in which the optical layer is laminated on a polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of the liquid crystal display device and the like can be improved. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When adhering the polarizing plate and other optical films, their optical axes can be set at an appropriate arrangement angle in accordance with the target retardation characteristics.

  An adhesive layer for adhering to other members such as a liquid crystal cell may be provided on the polarizing plate described above or an optical film in which at least one polarizing plate is laminated. The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is not particularly limited. For example, an acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer is appropriately selected. Can be used. In particular, those having excellent optical transparency such as an acrylic pressure-sensitive adhesive, exhibiting appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and being excellent in weather resistance, heat resistance and the like can be preferably used.

  In addition to the above, in terms of prevention of foaming and peeling phenomena due to moisture absorption, deterioration of optical properties and liquid crystal cell warpage due to differences in thermal expansion, etc., as well as formability of liquid crystal display devices with high quality and excellent durability An adhesive layer having a low moisture absorption rate and excellent heat resistance is preferred.

  The adhesive layer is, for example, natural or synthetic resins, in particular, tackifier resins, fillers or pigments made of glass fibers, glass beads, metal powders, other inorganic powders, colorants, antioxidants, etc. It may contain an additive to be added to the adhesive layer. Moreover, the adhesion layer etc. which contain microparticles | fine-particles and show light diffusibility may be sufficient.

  Attachment of the adhesive layer to one or both sides of the polarizing plate or the optical film can be performed by an appropriate method. For example, a pressure sensitive adhesive solution of about 10 to 40% by weight in which a base polymer or a composition thereof is dissolved or dispersed in a solvent composed of a suitable solvent alone or a mixture such as toluene and ethyl acetate is prepared. A method in which it is directly attached on a polarizing plate or an optical film by an appropriate development method such as a casting method or a coating method, or an adhesive layer is formed on a separator according to the above, and this is applied to a polarizing plate or an optical film. The method of moving up is mentioned.

  The pressure-sensitive adhesive layer can be provided on one side or both sides of a polarizing plate or an optical film as a superimposed layer of different compositions or types. Moreover, when providing in both surfaces, it can also be set as the adhesion layers of a different composition, a kind, thickness, etc. in the front and back of a polarizing plate or an optical film. The thickness of the pressure-sensitive adhesive layer can be appropriately determined according to the purpose of use and adhesive force, and is generally 1 to 500 μm, preferably 5 to 200 μm, particularly preferably 10 to 100 μm.

  On the exposed surface of the adhesive layer, a separator is temporarily attached and covered for the purpose of preventing contamination until it is put to practical use. Thereby, it can prevent contacting an adhesion layer in the usual handling state. As the separator, except for the above thickness conditions, for example, a suitable thin leaf body such as a plastic film, rubber sheet, paper, cloth, non-woven fabric, net, foam sheet, metal foil, laminate thereof, and the like, silicone type or Appropriate ones according to the prior art, such as those coated with an appropriate release agent such as a long mirror alkyl type, fluorine type or molybdenum sulfide, can be used.

  In the present invention, the polarizer, transparent protective film, optical film, and the like that form the polarizing plate described above, and each layer such as an adhesive layer include, for example, salicylic acid ester compounds, benzophenol compounds, benzotriazole compounds, and cyanoacrylates. It may be a compound having an ultraviolet absorbing ability by a method such as a method of treating with an ultraviolet absorber such as a compound based on nickel or a nickel complex salt compound.

  The polarizing plate or the optical film of the present invention can be preferably used for forming various devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, a polarizing plate or an optical film, and an illumination system as necessary, and incorporating a drive circuit. There is no limitation in particular except the point which uses the polarizing plate or optical film by invention, and it can apply according to the former. As the liquid crystal cell, any type such as a TN type, an STN type, or a π type can be used.

  An appropriate liquid crystal display device such as a liquid crystal display device in which a polarizing plate or an optical film is disposed on one side or both sides of a liquid crystal cell, or a backlight or a reflector used in an illumination system can be formed. In that case, the polarizing plate or optical film by this invention can be installed in the one side or both sides of a liquid crystal cell. When providing a polarizing plate or an optical film on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

  Next, an organic electroluminescence device (organic EL display device) will be described. Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a laminate of such a light emitting layer and an electron injection layer composed of a perylene derivative or the like, or a laminate of these hole injection layer, light emitting layer, and electron injection layer is known. It has been.

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

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

  In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.

  In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing a polarizing plate on the side, a retardation plate can be provided between the transparent electrode and the polarizing plate.

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

  That is, only the linearly polarized light component of the external light incident on the organic EL display device is transmitted by the polarizing plate. This linearly polarized light becomes generally elliptically polarized light by the phase difference plate, but becomes circularly polarized light particularly when the phase difference plate is a quarter wave plate and the angle between the polarization direction of the polarizing plate and the phase difference plate is π / 4. .

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

  Hereinafter, the present invention will be described in more detail with reference to examples. In the following, “parts” means parts by weight.

Example 1
A 13% by weight polyvinyl alcohol aqueous solution in which a polyvinyl alcohol resin having a polymerization degree of 2400 and a saponification degree of 98.5% is dissolved, and a liquid crystalline monomer having one acryloyl group at both ends of the mesogenic group (nematic liquid crystal) The temperature range is 40-70 ° C.) and glycerin are mixed such that polyvinyl alcohol: liquid crystalline monomer: glycerin = 100: 3: 15 (weight ratio), and heated to a temperature higher than the liquid crystal temperature range. To obtain a mixed solution. The bubbles present in the mixed solution were degassed by leaving them at room temperature (23 ° C.), and then coated by a casting method, followed by drying to obtain a white turbid mixed film having a thickness of 70 μm. This mixed film was heat-treated at 130 ° C. for 10 minutes.

  The mixed film is immersed in a 30 ° C. water bath to swell, and then in a 30 ° C. dyeing bath made of an aqueous solution (concentration 1% by weight) of a commercially available dichroic dye (manufactured by Kishida Chemical Co., Ltd., Congo Red). The film was stretched about 3 times. Then, it extended | stretched so that the total draw ratio might be 6 times in the crosslinking bath which consists of a 3 weight% boric acid aqueous solution of 50 degreeC. Furthermore, it cross-linked with a 4% by weight aqueous solution of boric acid at 30 ° C. Then, it dried at 50 degreeC for 4 minute (s), and obtained the polarizer of this invention.

(Confirmation of anisotropic scattering and measurement of refractive index)
When the obtained polarizer was observed with a polarizing microscope, it was confirmed that minute regions of liquid crystal monomers dispersed innumerably in the polyvinyl alcohol matrix were formed. This liquid crystalline monomer was oriented in the stretching direction, and the average length of the microregions in the stretching direction (Δn ² direction) was 1 to ² μm.

The refractive indexes of the matrix and the minute region were measured separately. The measurement was performed at 20 ° C. First, when the refractive index of the polyvinyl alcohol film alone stretched under the same stretching conditions was measured with an Abbe refractometer (measurement light 589 nm), the refractive index in the stretching direction (Δn ¹ direction) = 1.54, Δn ² direction. The refractive index was 1.52. The refractive index of the liquid crystal monomer (n _e: extraordinary refractive index and n _O: ordinary refractive index) was measured. n _O was measured by an Abbe refractometer (measurement light 589 nm) after aligning and coating a liquid crystalline monomer on a high refractive index glass subjected to vertical alignment treatment. On the other hand, a liquid crystalline monomer is injected into a horizontally aligned liquid crystal cell, and the phase difference (Δn × d) is measured with an automatic birefringence measuring apparatus (manufactured by Oji Scientific Instruments, automatic birefringence meter KOBRA21ADH). separately, a cell gap by a light interference method to measure (d), to calculate the Δn from the phase difference / cell gap, the sum of the Δn and n _O was n _e. n _e (corresponding to the refractive index in the Δn ¹ direction) = 1.64, n _O (corresponding to the refractive index in the Δn ² direction) = 1.52. Therefore, Δn ¹ = 1.64−1.54 = 0.10 and Δn ² = 1.52−1.52 = 0.00 were calculated.

Example 2
In Example 1, instead of a liquid crystalline monomer, spherical particles (average diameter 2 μm) of acrylic styrene having a refractive index of 1.51 are used so that polyvinyl alcohol: spherical fine particles = 100: 2 (weight ratio). A mixed solution was obtained in the same manner as in Example 1 except for mixing. Moreover, the mixed film was produced like Example 1 using the said mixed solution. Further, the obtained mixed film was wet-stretched in the same manner as in Example 1 to obtain a polarizer. Δn ¹ = 0.03 and Δn ² = 0.01. From the above, it was confirmed that desired anisotropic scattering was expressed.

Example 3
An aqueous solution (1) having a solid content concentration of 10% by weight containing 1000 parts of polyvinyl alcohol and 10 parts of a water-soluble absorption dichroic dye (Kishida Chemical Co., Ltd., Congo Red) was prepared. Further, a toluene solution (2) having a solid content concentration of 20% by weight containing 30 parts of a liquid crystalline thermoformable resin represented by the following formula 1 was prepared. The aqueous solution (1) and the toluene solution (2) were mixed together with 3 parts of a surfactant (Emazole L-10, manufactured by Kao Corporation). This mixed solution was stirred using a homomixer, and a film having a thickness of 70 μm was obtained by a solvent casting method. A film in which both solvents were sufficiently dried was uniaxially stretched at 120 ° C. at a stretch ratio of 3 and then rapidly cooled to obtain a polarizer (film).

式中、「６５」、「３５」はモル比を表し、便宜的にブロック体として表している。

In the formula, “65” and “35” represent molar ratios and are represented as block bodies for convenience.

The refractive index of the matrix and the minute region was measured separately in the same manner as in Example 1. The refractive index in the stretching direction (Δn ¹ direction) of the polyvinyl alcohol film alone stretched under the same stretching conditions was 1.54 and the refractive index in the Δn ² direction was 1.52. The refractive index of the liquid crystal monomer (n _e: extraordinary refractive index and n _O: ordinary refractive index) was measured. n (corresponding to △ n ¹ the refractive index in the direction) _e = 1.720, (corresponding to △ n ² the refractive index in the direction) n _O = 1.523, was. Therefore, Δn ¹ = 1.720−1.54 = 0.18 and Δn ² = 1.523−1.52 = 0.003 were calculated.

Further, the absorption axis of the dichroic dye and the optical axis direction indicating the Δn ¹ direction almost coincided. The average length in the Δn ² direction was 1 μm when the size of the minute region of the liquid crystalline thermoplastic resin dispersed and distributed by coloring due to the phase difference was estimated using a polarizing microscope.

Comparative Example 1
In Example 1, the same operation as in Example 1 was performed except that a film was prepared using the polyvinyl alcohol aqueous solution itself. In addition, the obtained film was wet-stretched in the same manner as in Example 1 to obtain a polarizer.

Comparative Example 2
Example 1 except that in Example 1, a film was prepared using an iodine-potassium iodide aqueous solution (iodine concentration 0.05 wt%, potassium iodide 0.35 wt%) instead of the dichroic dye aqueous solution. The same operation as 1 was performed. In addition, the obtained film was subjected to wet stretching in the same manner as in Example 1, and a polarizer was obtained in the same manner as in Example 1 except that the color tone was adjusted with an aqueous potassium iodide solution during washing with water. It was.

(Evaluation)
The optical properties of the polarizers (samples) obtained in Examples and Comparative Examples were measured with a spectrophotometer with an integrating sphere (U-4100 manufactured by Hitachi, Ltd.). The transmittance for each linearly polarized light (550 nm) was measured with 100% of the completely polarized light obtained through the Glan-Thompson prism polarizer.

The degree of polarization P was calculated by P = {(k ₁ −k ₂ ) / (k ₁ + k ₂ )} × 100. The single transmittance T was calculated by T = (k ₁ + k ₂ ) / 2.

  For the haze value, the haze value for linearly polarized light in the maximum transmittance direction and the haze value for linearly polarized light in the absorption direction (the orthogonal direction thereof) were measured. The haze value is measured according to JIS K 7136 (Plastic—How to determine haze of transparent material) using a haze meter (HM-150 manufactured by Murakami Color Research Laboratory) and a commercially available polarizing plate (manufactured by Nitto Denko Corporation). NPF-SEG1224DU: single unit transmittance of 43%, polarization degree of 99.96%) was placed on the incident surface side of the measurement light of the sample, and measurement was performed with the commercially available polarizing plate and the sample (polarizer) extending in the orthogonal direction. Indicates the haze value of the hour. However, with a commercially available light source of a Heizometer, the amount of light when orthogonal is less than the sensitivity limit of the detector, so the light of a separately provided high-intensity halogen lamp is incident using an optical fiber, and within the detection sensitivity After that, the shutter was manually opened and closed, and the haze value was calculated.

  Further, the ratio of the backscattering intensity to the incident light intensity was measured. The backscattering intensity was obtained by reflection measurement with a spectrophotometer with a 5 ° gradient integrating sphere (manufactured by Hitachi, U-4100). A black acrylic plate was bonded to the back surface of the sample with an acrylic adhesive, and all reflections on the back surface were absorbed, and only the reflection and scattering intensity from the front surface and the back of the sample were determined.

For the evaluation of unevenness, a sample (polarizer) is placed on the upper surface of a backlight used in a liquid crystal display in a dark room, and the polarizing axis is orthogonal with a commercially available polarizing plate (NPF-SEG1224DU manufactured by Nitto Denko Corporation) as an analyzer. The levels were visually confirmed according to the following criteria.
X: Level at which unevenness can be confirmed visually.
○: Level at which unevenness cannot be confirmed visually.

For the evaluation of heat resistance, a triacetyl cellulose film (thickness: 80 μm) was bonded to both sides of a polarizer using a water-soluble adhesive and dried to prepare a polarizing plate. After leaving this polarizing plate in an atmosphere of 120 ° C. for 1 hour, the degree of deterioration was visually evaluated according to the following criteria. The evaluation of polarization was performed by confirming the light omission and hue when the polarization axes of the same two samples were arranged orthogonally.
X: Deterioration of polarization performance can be visually confirmed before and after the test.
○: Deterioration of polarization performance cannot be visually confirmed before and after the test.

上記表１に示す通り、実施例の染料系偏光子は比較例１の染料系偏光子に比べて、直交時の透過率のヘイズ値が高く、バラツキによるムラが散乱によって隠蔽され確認できなくなっていることが分かる。また実施例の染料系偏光子は、比較例２との対比により染料系偏光子の特徴である耐熱性も確保していることが分かる。

As shown in Table 1 above, the dye-based polarizer of the example has a higher haze value of the transmittance when orthogonal than the dye-based polarizer of Comparative Example 1, and unevenness due to dispersion is hidden by scattering and cannot be confirmed. I understand that. It can also be seen that the dye-based polarizers of the Examples also ensure heat resistance, which is a feature of the dye-based polarizer, by comparison with Comparative Example 2.

  Next, the polarizing plates of Example 1 and Comparative Example 1 were replaced and replaced with the polarizing plate on the backlight side of a commercially available twisted nematic liquid crystal panel. When this was displayed in black in a dark room and the level of unevenness was confirmed, when the polarizing plate of Example 1 was mounted as compared with the polarizing plate of Comparative Example 1, no unevenness was confirmed and visibility was improved. It was very good.

  Since the obtained polarizer has an absorption dichroic dye in the matrix, the optical path length through which light passes through the absorption layer becomes longer. Therefore, the polarization performance is higher than that of the polarizer described in JP-A-2002-207118. The improvement effect is great. Also, the manufacturing process is simple.

  As a polarizer similar to the structure of the polarizer of the present invention, JP-A No. 2002-207118 discloses a resin matrix in which a mixed phase of a liquid crystalline birefringent material and an absorbing dichroic material is dispersed. Has been. The effect is the same as that of the present invention. However, as compared with the case where the absorbing dichroic material is present in the dispersed phase as in JP-A-2002-207118, the one where the absorbing dichroic material is present in the matrix layer as in the present invention, Although the scattered polarized light passes through the absorption layer, the optical path length becomes long, so that more scattered light can be absorbed. Therefore, the effect of improving the polarization performance is much higher in the present invention. Also, the manufacturing process is simple.

  JP-T-2000-506990 discloses an optical body in which a dichroic dye is added to either the continuous phase or the dispersed phase. In the background of the invention described in JP-T-2000-506990, it is stated that Aphonin et al. Describe optical characteristics of a stretched film in which liquid crystal droplets are arranged in a polymer matrix. However, Aphonin et al. Mentioned an optical film composed of a matrix phase and a dispersed phase (liquid crystal component) without using a dichroic dye, and the liquid crystal component is not a polymer of a liquid crystal polymer or a liquid crystal monomer. The birefringence of the liquid crystal component in the film is typically temperature dependent and sensitive. On the other hand, the present invention provides a polarizer comprising a film having a structure in which minute regions are dispersed in a matrix formed of a light-transmitting thermoplastic resin containing an absorbing dichroic dye. The liquid crystalline material of the invention is a liquid crystal polymer that is aligned in the liquid crystal temperature range and then cooled to room temperature and fixed in alignment. In the liquid crystal monomer, the alignment is fixed in the same manner and then fixed by ultraviolet curing or the like. In other words, the birefringence of a minute region formed of a liquid crystalline material does not change with temperature.

It is a conceptual top view which shows an example of the polarizer of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Translucent thermoplastic resin 2 Absorption dichroic dye 3 Micro area | region

Claims (15)

A polarizer comprising a film having a structure in which minute regions are dispersed in a matrix formed of a light-transmitting thermoplastic resin containing an absorbing dichroic dye,
A polarizer having a transmittance of 80% or more for linearly polarized light in a transmission direction, a haze value of 10% or less, and a haze value for linearly polarized light in an absorption direction of 50% or more.   The polarizer according to claim 1, wherein the minute region is formed of an oriented birefringent material.   The polarizer according to claim 2, wherein the birefringent material exhibits liquid crystallinity at least at the time of the alignment treatment.   4. The polarizer according to claim 2, wherein the birefringence of the micro region is 0.02 or more. The refractive index difference for each optical axis direction between the birefringent material forming the minute region and the translucent thermoplastic resin is
The refractive index difference (Δn ¹ ) in the axial direction showing the maximum value is 0.03 or more,
The refractive index difference (Δn ² ) in two axial directions orthogonal to the Δn ¹ direction is 50% or less of the Δn ^1. 5. Polarizer.   The polarizer according to claim 1, wherein the ratio of the backscattering intensity to the incident light intensity is 30% or less. The polarizer according to claim 1, wherein the absorption dichroic dye has an absorption axis oriented in the Δn ¹ direction.   The polarizer according to claim 1, wherein the film is produced by stretching. The polarizer according to claim 1, wherein the minute region has a length in the Δn ² direction of 0.05 to 500 μm.   The birefringent material forming the minute region is a liquid crystalline thermoplastic resin in which a nematic phase or a smectic phase appears in a temperature region lower than the glass transition temperature of the light-transmitting thermoplastic resin. Item 10. The polarizer according to any one of Items 3 to 9.   A birefringent material that forms a minute region is a polymerized material after aligning a liquid crystal monomer in which a nematic or smectic phase appears in a temperature region lower than the glass transition temperature of a light-transmitting thermoplastic resin. The polarizer according to claim 3, wherein the polarizer is present.   The polarizer according to claim 1, wherein the absorbing dichroic dye is a dye having at least one absorption band having a dichroic ratio of 3 or more in the visible light wavelength region.   The polarizing plate which provided the transparent protective layer in the at least single side | surface of the polarizer in any one of Claims 1-12.   An optical film, wherein at least one of the polarizer according to claim 1 or the polarizing plate according to claim 13 is laminated.   An image display device comprising the polarizer according to claim 1, the polarizing plate according to claim 13, or the optical film according to claim 14.

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