KR102563131B1 - Dyed triacetyl cellulose film, polarizing plate using the film, method for producing polarizing plate, polarizing plate with retardation layer, image display device, and image adjustment method of image display device - Google Patents

Abstract

The present invention provides a polarizing plate and a polarizing plate with a retardation layer capable of realizing a neutral reflective color when applied to an image display device. The polarizing plate of the present invention includes a polarizing film and a protective layer disposed on a viewing side of the polarizing film. The thickness of the polarizing film is 8 μm or less, the protective layer is composed of a triacetyl cellulose film dyed with iodine, and the transmittance of the protective layer at a wavelength of 400 nm is 65% or less. A polarizing plate with a retardation layer of the present invention includes the polarizing plate described above and a retardation layer disposed on the opposite side of the viewing side of the polarizing plate. Re (550) of the retardation layer is 100 nm to 190 nm, Re (450) / Re (550) is 0.8 or more and less than 1, and the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizing film of the polarizing plate is 40 ° to 50 °. am.

Description

Dyed triacetyl cellulose film, polarizing plate using the film, method for producing polarizing plate, polarizing plate with retardation layer, image display device, and image adjustment method of image display device

The present invention relates to a dyed triacetyl cellulose film, a polarizing plate using the film, a method for producing the polarizing plate, a polarizing plate with a retardation layer, an image display device, and an image adjustment method for the image display device.

BACKGROUND OF THE INVENTION In recent years, image display devices typified by liquid crystal display devices and electroluminescence (EL) display devices (eg, organic EL display devices and inorganic EL display devices) are rapidly spreading. A polarizing plate and a retardation plate are typically used in the image display device. Practically, a polarizing plate with a retardation layer in which a polarizing plate and a retardation plate are integrated is widely used (for example, Patent Document 1), and recently, as the demand for thinning of image display devices has become stronger, a polarizing plate and a polarizing plate with a retardation layer have been developed. Also, the demand for thinning is getting stronger. As one of the means for reducing the thickness of the polarizing plate and the polarizing plate with the retardation layer, the thickness reduction of the polarizing film can be cited. However, when a polarizing plate including a thin polarizing film or a polarizing plate with a retardation layer is used for an image display device, there is a problem that the reflected color is bluish.

Japanese Patent Publication No. 3325560

The present invention has been made to solve the above conventional problems, and its main object is to realize a polarizing plate and a polarizing plate with a retardation layer capable of realizing a neutral reflective color when applied to an image display device, and such a polarizing plate and a polarizing plate with a retardation layer. It is to provide a dyed triacetyl cellulose film.

The dyed triacetyl cellulose film according to the embodiment of the present invention is dyed with iodine, and has a transmittance of 65% or less at a wavelength of 400 nm, and a transmittance Y corrected for visibility of 80% or more.

According to another aspect of the present invention, a polarizing plate is provided. This polarizing plate includes a polarizing film and a protective layer disposed on at least one side of the polarizing film. The thickness of the polarizing film is 8 μm or less, and the protective layer is composed of the above dyed triacetyl cellulose film.

According to another situation of this invention, the manufacturing method of the said polarizing plate is provided. This manufacturing method includes forming a polyvinyl alcohol-based resin layer on one side of a long thermoplastic resin substrate to form a laminate; subjecting the layered product to dyeing treatment and stretching treatment to make the polyvinyl alcohol-based resin layer a polarizing film; Dyeing the triacetyl cellulose film with iodine to make the transmittance at a wavelength of 400 nm 65% or less, and the transmittance Y corrected for visibility to 80% or more; and bonding the dyed triacetyl cellulose film to the polarizing film.

In one embodiment, the dyeing includes immersing the triacetyl cellulose film in an iodine aqueous solution having an iodine concentration of 0.1% by weight or more.

According to another situation of this invention, the polarizing plate with a retardation layer is provided. This polarizing plate with a retardation layer includes the polarizing plate described above and a retardation layer disposed on the opposite side of the viewing side of the polarizing plate. Re(550) of the retardation layer is 100 nm to 190 nm, Re(450)/Re(550) is 0.8 or more and less than 1, and the angle between the slow axis of the retardation layer and the absorption axis of the polarizing film of the polarizing plate is 40°. is ~50°.

In one embodiment, the retardation layer is composed of a polycarbonate-based resin film.

In one embodiment, the polarizing plate with a retardation layer further includes another retardation layer outside the retardation layer, and the refractive index characteristic of the other retardation layer shows a relationship of nz > nx = ny.

In one embodiment, the polarizing plate with a retardation layer is a long picture, the polarizing film has an absorption axis in the direction of a long picture, and the retardation layer is an obliquely stretched film having a slow axis in a direction forming an angle of 40 ° to 50 ° with respect to the direction of a long picture. . In one embodiment, the polarizing plate with a retardation layer can be wound into a roll.

A polarizing plate with a retardation layer according to another embodiment of the present invention includes the above polarizing plate and a retardation layer disposed on a viewing side and an opposite side of the polarizing plate. The retardation layer has a laminated structure of an alignment-fixed layer of a first liquid crystal compound and an alignment-fixed layer of a second liquid crystal compound. Re (550) of the alignment-fixed layer of the first liquid crystal compound is 200 nm to 300 nm, and the angle between its slow axis and the absorption axis of the polarizing film is 10° to 20°; Re (550) of the alignment hardening layer of the second liquid crystal compound is 100 nm to 190 nm, and an angle between its slow axis and the absorption axis of the polarizing film is 70° to 80°.

In one embodiment, the polarizing plate with a retardation layer further includes a conductive layer or an isotropic substrate with a conductive layer on the outside of the retardation layer.

According to another aspect of the present invention, an image display device is provided. This image display device is provided with the polarizing plate or the polarizing plate with a retardation layer.

In one embodiment, the image display device is an organic electroluminescent display device or an inorganic electroluminescent display device.

According to another aspect of the present invention, an image adjustment method of an image display device is provided. This method includes attaching the above polarizing plate or the above polarizing plate with a retardation layer to the viewing side of an image display cell to bring the reflected color closer to neutral.

According to the present invention, by using an iodine-dyed triacetyl cellulose film having a predetermined transmittance at a predetermined wavelength and a predetermined visibility-corrected transmittance Y as a protective layer of a polarizing film, when applied to an image display device, a neutral reflective color can be realized. A polarizing plate and a polarizing plate with a retardation layer can be realized.

1 is a schematic view showing an example of drying shrinkage treatment using a heating roll in a method for producing a polarizing film used for a polarizing plate or a polarizing plate with a retardation layer according to an embodiment of the present invention.
2 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to one embodiment of the present invention.
3 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to another embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of this invention is described, this invention is not limited to these embodiment.

(Definition of Terms and Symbols)

Definitions of terms and symbols in this specification are as follows.

(1) Refractive index (nx, ny, nz)

'nx' is the refractive index in the direction in which the in-plane refractive index is maximized (ie, the slow axis direction), 'ny' is the refractive index in the direction orthogonal to the slow axis within the plane (ie, the fast axis direction), and 'nz' is is the refractive index in the thickness direction.

(2) In-plane phase difference (Re)

'Re(λ)' is an in-plane retardation measured with light having a wavelength of λ nm at 23°C. For example, 'Re(550)' is an in-plane retardation measured with light having a wavelength of 550 nm at 23°C. Re(λ) can be obtained by the formula: Re(λ)=(nx-ny)×d when the thickness of the layer (film) is d(nm).

(3) Phase difference in thickness direction (Rth)

'Rth(λ)' is the phase difference in the thickness direction measured with light having a wavelength of λ nm at 23°C. For example, 'Rth(550)' is the phase difference in the thickness direction measured with light having a wavelength of 550 nm at 23°C. Rth(λ) can be obtained by the formula: Rth(λ)=(nx-nz)×d when the thickness of the layer (film) is d(nm).

(4) Nz factor

The Nz coefficient can be obtained by Nz=Rth/Re.

(5) Angle

When referring to an angle in this specification, the angle includes both clockwise and counterclockwise directions with respect to the reference direction. Thus, for example, '45°' means ±45°.

A. Polarizer

According to an embodiment of the present invention, a triacetyl cellulose (TAC) film dyed with iodine is provided. This dyed TAC film has a transmittance of 65% or less at a wavelength of 400 nm, and a transmittance Y corrected for visibility (hereinafter sometimes referred to as Y-value transmittance) of 80% or more. A dyed TAC film can be suitably used for the protective layer of a polarizing plate. A polarizing plate according to an embodiment of the present invention includes a polarizing film and a protective layer disposed on at least one side of the polarizing film. That is, the protective layer may be provided on both sides of the polarizing film, may be provided only on the viewing side of the polarizing film, or may be provided only on the viewing side and the opposite side of the polarizing film. In an embodiment of the present invention, at least one of the protective layers is composed of a dyed TAC film. According to one embodiment, in the polarizing plate having a viewer-side protective layer/polarizing film configuration, the viewer-side protective layer is composed of a dyed TAC film.

A-1. polarizing film

The polarizing film is typically composed of a polyvinyl alcohol (PVA)-based resin film containing iodine. The thickness of the polarizing film is typically 8 μm or less, preferably 7 μm or less, more preferably 5 μm or less, still more preferably 3 μm or less. The lower limit of the thickness of the polarizing film may be 1 μm in one embodiment and 2 μm in another embodiment.

The polarizing film preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizing film is preferably 42.0% or more, more preferably 42.5% or more, still more preferably 43.0% or more. On the other hand, the single transmittance is preferably 47.0% or less, more preferably 46.0% or less. The degree of polarization of the polarizing film is preferably 99.95% or higher, more preferably 99.99% or higher. On the other hand, the degree of polarization is preferably 99.998% or less. The polarizing film used in the embodiment of the present invention can achieve both such high single transmittance and high polarization degree. The single transmittance is typically a Y value measured using an ultraviolet/visible ray spectrophotometer and corrected for visibility. In addition, single transmittance is a value when the refractive index of one surface of a polarizing plate is 1.50 and the refractive index of the other surface is converted into 1.53. The degree of polarization can be obtained by the following formula, based on the parallel transmittance (Tp) and the orthogonal transmittance (Tc), which are typically measured using an ultraviolet/visible ray spectrophotometer and corrected for visibility.

Polarization degree (%) = {(Tp-Tc)/(Tp+Tc)} ^1/2 × 100

In one embodiment, the transmittance of a thin polarizing film of 8 µm or less is typically measured for a laminate of a polarizing film (surface refractive index: 1.53) and a protective film (refractive index: 1.50), ultraviolet / visible light It is measured using a spectrophotometer. The reflectance at the interface of each layer changes depending on the refractive index of the surface of the polarizing film and/or the refractive index of the surface of the protective film in contact with the air interface, and as a result, the measured transmittance value may change. Therefore, for example, when a protective film having a refractive index other than 1.50 is used, the measured value of the transmittance may be corrected according to the refractive index of the surface of the protective film in contact with the air interface. Specifically, the correction value C of the transmittance is expressed by the following formula using the reflectance R ₁ (transmission axis reflectance) of polarized light parallel to the transmission axis at the interface between the protective film and the air layer.

C=R ₁ -R ₀

R ₀ =((1.50-1) ² /(1.50+1) ² )×(T ₁ /100)

R ₁ =((n ₁ -1) ² /(n ₁ +1) ² )×(T ₁ /100)

Here, R ₀ is the transmittance reflectance when a protective film having a refractive index of 1.50 is used, n ₁ is the refractive index of the protective film used, and T ₁ is the transmittance of the polarizing film. For example, when a base material having a surface refractive index of 1.53 (such as a cycloolefin-based film or a film with a hard coat layer) is used as a protective film, the correction amount C is about 0.2%. In this case, by adding 0.2% to the transmittance obtained by the measurement, it is possible to convert the polarizing film having a surface refractive index of 1.53 into the transmittance in the case of using a protective film having a refractive index of 1.50. In addition, according to the calculation based on the above formula, the amount of change in the correction value C when the transmittance T ₁ of the polarizing film is changed by 2% is 0.03% or less, and the influence of the transmittance of the polarizing film on the value of the correction value C is limited. In addition, when the protective film has absorption other than surface reflection, appropriate correction can be performed according to the amount of absorption.

The polarizing film may be produced using a single resin film, or may be produced using a laminate of two or more layers.

As a specific example of a polarizing film obtained using a laminate, a polarizing film obtained using a laminate of a resin substrate and a PVA-based resin layer coated and formed on the resin substrate is exemplified. A polarizing film obtained by using a laminate of a resin substrate and a PVA-based resin layer coated and formed on the resin substrate is, for example, coated with a PVA-based resin solution on the resin substrate and dried to form a PVA-based resin layer on the resin substrate to form a PVA-based resin layer on the resin substrate. Obtaining a laminated body with a PVA-based resin layer; It can be produced by stretching and dyeing the layered product to use the PVA-based resin layer as a polarizing film. In this embodiment, extending|stretching typically includes immersing a layered product in boric acid aqueous solution and extending|stretching. Further, the stretching may further include air-stretching the laminate at a high temperature (eg, 95° C. or higher) before stretching in a boric acid aqueous solution, if necessary.

More specifically, the method for producing a polarizing film is to form a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin on one side of a long thermoplastic resin substrate to form a laminate, and in the laminate, Air-assisted stretching treatment, dyeing treatment, underwater stretching treatment, and drying shrinkage treatment for shrinking by 2% or more in the width direction by heating while conveying in the longitudinal direction are performed in this order. Accordingly, a polarizing film having a thickness of 8 μm or less and having excellent optical properties can be provided. That is, by introducing auxiliary stretching, even when applying PVA on a thermoplastic resin, it becomes possible to increase the crystallinity of PVA and achieve high optical properties. In addition, at the same time, by increasing the orientation of PVA in advance, it is possible to prevent problems such as deterioration in orientation or dissolution of PVA when immersed in water in a subsequent dyeing step or drawing step, and to achieve high optical properties. do. Further, in the case where the PVA-based resin layer is immersed in a liquid, the disorder of the orientation of the polyvinyl alcohol molecules and the decrease in the orientation can be suppressed compared to the case where the PVA-based resin layer does not contain a halide. Accordingly, the optical properties of the polarizing film obtained through a treatment step performed by immersing the laminate in a liquid, such as dyeing treatment and underwater stretching treatment, can be improved. In addition, optical properties can be improved by shrinking the laminate in the width direction by drying shrinkage treatment. The details of the manufacturing method of the polarizing film will be described later in Section B.

A-2. protective layer

As described above, in the embodiment of the present invention, at least one of the protective layer disposed on the viewer side (hereinafter referred to as the viewer side protective layer) and the protective layer disposed on the opposite side of the viewer side (hereinafter referred to as the inner protective layer) is dyed TAC made up of film. Since the inner protective layer can be preferably omitted from the viewpoint of thinning and lightening the polarizing plate, according to one embodiment, in the polarizing plate having the configuration of the viewing side protective layer/polarizing film, the viewing side protective layer is composed of a dyed TAC film. . By using the dyed TAC film for the viewer-side protective layer and/or the inner protective layer, it is possible to prevent the reflected color of the image display device from being blue even when a thin (e.g., 8 μm or less) polarizing film is used, , as a result, a very good (neutral) reflection color can be realized.

When the visual side protective layer and the inner protective layer are disposed, and only one of them is composed of a dyed TAC film, the other protective layer is formed of any suitable film that can be used as a protective layer of a polarizing film. Specific examples of the material serving as the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and transparent resins such as polysulfone, polystyrene, polynorbornene, polyolefin, (meth)acrylic, and acetate resins. Further, thermosetting resins such as (meth)acrylic, urethane-based, (meth)acrylurethane-based, epoxy-based, and silicone-based resins or ultraviolet curable resins may be used. In addition to this, glassy type polymers, such as a siloxane type polymer, are also mentioned, for example. Moreover, the polymer film of Unexamined-Japanese-Patent No. 2001-343529 (WO01/37007) can also be used. As the material for this film, a resin composition containing, for example, a thermoplastic resin having a substituted or unsubstituted imide group on its side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group on its side chain can be used. For example, isobutene and N- and a resin composition comprising an alternating copolymer containing methyl maleimide and an acrylonitrile/styrene copolymer. The polymer film may be, for example, an extrusion molding of the resin composition.

The transmittance of the dyed TAC film at a wavelength of 400 nm is 65% or less, preferably 60% or less, more preferably 55% or less, still more preferably 40% or less, and particularly preferably 35% or less. The lower limit of the transmittance may be, for example, 0.1%. When the transmittance is within this range, the reflected color can be further improved. In addition, the Y-value transmittance of the dyed TAC film is 80% or more, preferably 85% or more, and more preferably 90% or more. The Y-value transmittance is so preferable that it is high. The upper limit of the Y-value transmittance may be, for example, 98%. It is one of the characteristics of the dyed TAC film that the transmittance at a wavelength of 400 nm decreases remarkably, while the Y-value transmittance can maintain a high value.

It is presumed that the above effect by such a dyed TAC film is due to the following mechanism: The iodine content (absolute amount) of the thin polarizing film is small. The polarizing film used in the embodiment of the present invention is prepared by the method described in section B to be described later, so that the PVA-I ₅ ^- complex and PVA-I contributing to the absorption of visible light despite the small iodine content (absolute amount) ₃ ^- complex Since the total amount of source I ₅ ^- ions and I ₃ ^- ions can be maintained within a desired range, single transmittance and polarization degree can be maintained at high levels while being thin. Nevertheless, due to the small iodine content (absolute amount), the thin polarizing film tends to have low absorption of short-wavelength (e.g., 400 nm or less) light. According to an embodiment of the present invention, by using a dyed TAC film as a protective layer, the protective layer can absorb short-wavelength light. As a result, short-wavelength light can be sufficiently absorbed as a whole polarizing plate, and short-wavelength absorptivity of the thin polarizing film can be maintained. As a result, while maintaining the excellent characteristics of the thin polarizing film used in the embodiment of the present invention, it is possible to prevent the reflective color of the image display device from being bluish, and as a result, it is possible to realize a very good (neutral) reflective color. can In addition, when iodine is excessively contained in the thin polarizing film, a PVA-iodine complex is formed, so that the Y-value transmittance also decreases at the same time. On the other hand, since iodine does not form a complex in the TAC film, iodine absorption is limited to a short wavelength, and it is possible to suppress the short-wavelength transmittance while maintaining the Y-value transmittance.

The visual side protective layer may be subjected to surface treatment such as hard coat treatment, antireflection treatment, anti-sticking treatment, and antiglare treatment as needed. In addition, / or, if necessary, the protective layer on the viewer side is subjected to processing to improve visibility when viewed through polarized sunglasses (typically, imparting a (other) circular polarization function, imparting an ultra-high phase difference), There may be. By performing such a process, excellent visibility can be realized even when the display screen is visually recognized through a polarizing lens such as polarized sunglasses. Therefore, the polarizing plate or the polarizing plate with the retardation layer can be suitably applied to an image display device that can be used outdoors.

The thickness of the visual side protective layer is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, still more preferably 10 μm to 35 μm. In addition, when the surface treatment is performed, the thickness of the viewing side protective layer is the thickness including the thickness of the surface treatment layer.

In one embodiment, the inner protective layer is preferably optically isotropic. In this specification, 'optically isotropic' means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is -10 nm to +10 nm. The inner protective layer, in one embodiment, may be a retardation layer having any suitable retardation value. In this case, the in-plane retardation Re (550) of the retardation layer is, for example, 110 nm to 150 nm. The thickness of the inner protective layer is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, still more preferably 10 μm to 30 μm. As described above, from the viewpoint of thinning and lightening, the inner protective layer may be omitted.

B. Manufacturing method of polarizer

B-1. Manufacturing method of polarizing film

The polarizing film is, for example, formed by forming a polyvinyl alcohol-based resin layer (PVA-based resin layer) containing a halide and a polyvinyl alcohol-based resin (PVA-based resin) on one side of a long thermoplastic resin substrate to form a laminate, and lamination. Manufactured by a method comprising subjecting a sieve to an air-assisted stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment for shrinking by 2% or more in the width direction by heating while conveying in the longitudinal direction in this order. It can be. The content of the halide in the PVA-based resin layer is preferably 5 parts by weight to 20 parts by weight with respect to 100 parts by weight of the PVA-based resin. The drying shrinkage treatment is preferably performed using a heating roll, and the temperature of the heating roll is preferably 60°C to 120°C. The shrinkage rate in the width direction of the layered product by the drying shrinkage treatment is preferably 2% or more. According to such a manufacturing method, the polarizing film described in the above section A-1 can be obtained. In particular, by preparing a laminate comprising a PVA-based resin layer containing a halide, stretching the laminate by multi-step stretching including air-assisted stretching and underwater stretching, and heating the laminate after stretching with a heating roll to obtain excellent optical properties. A polarizing film having characteristics (typically single transmittance and polarization degree) can be obtained.

B-1-1. Fabrication of the laminate

Arbitrary suitable methods are employable as a method of producing the laminated body of a thermoplastic resin base material and a PVA system resin layer. Preferably, a PVA-based resin layer is formed on the thermoplastic resin substrate by applying a coating liquid containing a halide and a PVA-based resin to the surface of the thermoplastic resin substrate and drying it. As described above, the content of the halide in the PVA-based resin layer is preferably 5 parts by weight to 20 parts by weight with respect to 100 parts by weight of the PVA-based resin.

Arbitrary suitable methods can be adopted as a method of applying the coating liquid. For example, roll coating method, spin coating method, wire bar coating method, dip coating method, die coating method, curtain coating method, spray coating method, knife coating method (comma coating method etc.), etc. are mentioned. The coating/drying temperature of the coating liquid is preferably 50°C or higher.

The thickness of the PVA-based resin layer is preferably 3 μm to 40 μm, more preferably 3 μm to 20 μm.

Before forming the PVA-based resin layer, surface treatment (for example, corona treatment) may be performed on the thermoplastic resin substrate, or an easily bonding layer may be formed on the thermoplastic resin substrate. By performing such a process, the adhesiveness of a thermoplastic resin base material and a PVA system resin layer can be improved.

B-1-1-1. Thermoplastic resin substrate

As the thermoplastic resin substrate, any suitable thermoplastic resin film can be employed. About the detail of a thermoplastic resin base material, it describes, for example in Unexamined-Japanese-Patent No. 2012-73580 or Japanese Patent No. 6470455. These publications are incorporated herein by reference in their entirety.

B-1-1-2. coating liquid

The coating liquid contains a halide and a PVA-based resin as described above. The coating liquid is typically a solution obtained by dissolving the halide and the PVA-based resin in a solvent. Examples of the solvent include water, dimethylsulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, various glycols, polyhydric alcohols such as trimethylolpropane, and amines such as ethylenediamine and diethylenetriamine. there is. These can be used individually or in combination of 2 or more types. Among these, water is preferable. The concentration of the PVA-based resin in the solution is preferably 3 parts by weight to 20 parts by weight based on 100 parts by weight of the solvent. With such a resin concentration, a uniform coating film in close contact with the thermoplastic resin substrate can be formed. The content of the halide in the coating liquid is preferably 5 parts by weight to 20 parts by weight with respect to 100 parts by weight of the PVA-based resin.

You may mix|blend additives with a coating liquid. As an additive, a plasticizer, surfactant, etc. are mentioned, for example. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin. Examples of the surfactant include nonionic surfactants. These can be used for the purpose of further improving the uniformity, dyeability, and stretchability of the obtained PVA-based resin layer.

Arbitrary suitable resin can be employ|adopted as said PVA-type resin. Details of the PVA-based resin are described in, for example, Japanese Unexamined Patent Publication No. 2012-73580 or Japanese Patent No. 6470455 (above).

Arbitrary appropriate halides can be employed as the halide. Examples include iodide and sodium chloride. Examples of the iodide include potassium iodide, sodium iodide and lithium iodide. Among these, potassium iodide is preferable.

The amount of the halide in the coating liquid is preferably 5 parts by weight to 20 parts by weight based on 100 parts by weight of the PVA-based resin, more preferably 10 parts by weight to 15 parts by weight based on 100 parts by weight of the PVA-based resin. When the amount of the halide with respect to 100 parts by weight of the PVA-based resin exceeds 20 parts by weight, the halide may bleed out and the finally obtained polarizing film may become cloudy.

In general, when the PVA-based resin layer is stretched, the orientation of the polyvinyl alcohol molecules in the PVA-based resin increases, but when the stretched PVA-based resin layer is immersed in a water-containing liquid, the orientation of the polyvinyl alcohol molecules is disturbed and the orientation There are cases where this declines. In particular, when the laminate of the thermoplastic resin substrate and the PVA-based resin layer is stretched in boric acid water, the orientation degree tends to decrease when the laminate is stretched in boric acid water at a relatively high temperature to stabilize the stretching of the thermoplastic resin substrate. this is remarkable For example, it is common that stretching of a PVA film alone in boric acid is performed at 60°C, whereas stretching of a laminate of A-PET (thermoplastic resin substrate) and a PVA-based resin layer is performed at a high temperature of around 70°C. In this case, the orientation of PVA in the initial stage of stretching may be lowered in the stage before rising by underwater stretching. In contrast, by preparing a laminate of a PVA-based resin layer containing a halide and a thermoplastic resin substrate, and stretching the laminate in air at high temperature (auxiliary stretching) before stretching the laminate in boric acid, the PVA of the laminate after auxiliary stretching Crystallization of the PVA-based resin in the resin-based layer can be promoted. As a result, in the case where the PVA-based resin layer is immersed in a liquid, the disorder of the orientation of the polyvinyl alcohol molecules and the decrease in the orientation can be suppressed compared to the case where the PVA-based resin layer does not contain a halide. Accordingly, the optical properties of the polarizing film obtained through a treatment step performed by immersing the laminate in a liquid, such as dyeing treatment and underwater stretching treatment, can be improved.

B-1-2. Air Assisted Stretching Treatment

In particular, in order to obtain high optical properties, a method of two-stage stretching combining dry stretching (auxiliary stretching) and stretching in boric acid is selected. By introducing auxiliary stretching such as two-step stretching, it is possible to stretch while suppressing crystallization of the thermoplastic resin substrate, and solve the problem that stretchability is lowered due to excessive crystallization of the thermoplastic resin substrate in subsequent stretching in boric acid. can be stretched at a higher magnification. Furthermore, in the case of applying a PVA-based resin on a thermoplastic resin substrate, in order to suppress the influence of the glass transition temperature of the thermoplastic resin substrate, it is necessary to lower the application temperature compared to the case of applying the PVA-based resin on a conventional metal drum, , As a result, the crystallization of the PVA-based resin is relatively low, and a problem that sufficient optical properties cannot be obtained may occur. On the other hand, by introducing auxiliary stretching, the crystallinity of the PVA-based resin can be increased even when the PVA-based resin is applied on the thermoplastic resin, and high optical properties can be achieved. In addition, by simultaneously increasing the orientation of the PVA-based resin in advance, it is possible to prevent problems such as deterioration in the orientation of the PVA-based resin and dissolution when immersed in water in a subsequent dyeing step or drawing step, thereby achieving high optical properties. it becomes possible to do

The stretching method of air assisted stretching may be fixed end stretching (eg, stretching using a tenter stretching machine) or free end stretching (eg, uniaxial stretching by passing a laminate between rolls having different circumferential speeds). However, in order to obtain high optical properties, free end stretching may be actively employed. In one embodiment, the air stretching treatment includes a heating roll stretching step of stretching the laminate by a circumferential speed difference between heating rolls while conveying the laminate in its longitudinal direction. The aerial stretching treatment typically includes a zone stretching process and a hot roll stretching process. In addition, the order of the zone stretching process and the hot roll stretching process is not limited, and the zone stretching process may be performed first, or the hot roll stretching process may be performed first. The zone stretching step may be omitted. In one embodiment, the zone stretching process and the hot roll stretching process are performed in this order. Further, in another embodiment, the film is stretched by gripping an end portion of the film in a tenter stretching machine and extending the distance between tenters in the flow direction (the expansion of the distance between tenters becomes a stretching ratio). At this time, the distance of the tenter in the width direction (direction perpendicular to the flow direction) is set to be arbitrarily close. Preferably, with respect to the stretching ratio in the flow direction, it can be set to be approached by free end stretching. In the case of free end drawing, the shrinkage rate in the width direction = (1/stretching ratio) is calculated as ^1/2 .

Air assisted stretching may be performed in one step or may be performed in multiple steps. When performing in multiple steps, the draw ratio is the product of the draw ratios of each step. The stretching direction in air assisted stretching is preferably substantially the same as that in underwater stretching.

The draw ratio in air assisted stretching is preferably 2.0 times to 3.5 times. The maximum stretching ratio when air assisted stretching and underwater stretching are combined is preferably 5.0 times or more, more preferably 5.5 times or more, still more preferably 6.0 times or more of the original length of the laminate. In this specification, 'maximum draw ratio' refers to a draw ratio immediately before the laminate is broken, and refers to a value 0.2 lower than the value obtained by checking the draw ratio at which the laminate is broken separately.

The stretching temperature of the air-assisted stretching can be set to any suitable value depending on the forming material of the thermoplastic resin substrate, the stretching method, and the like. The stretching temperature is preferably equal to or higher than the glass transition temperature (Tg) of the thermoplastic resin substrate, more preferably equal to or higher than the glass transition temperature (Tg) of the thermoplastic resin substrate (Tg) + 10°C, particularly preferably equal to or higher than Tg + 15°C. On the other hand, the upper limit of the stretching temperature is preferably 170°C. By stretching at such a temperature, rapid crystallization of the PVA-based resin can be suppressed, and problems caused by the crystallization (for example, obstruction of orientation of the PVA-based resin layer by stretching) can be suppressed. The crystallization index of the PVA-based resin after air-assisted stretching is preferably 1.3 to 1.8, more preferably 1.4 to 1.7. The crystallization index of the PVA-based resin can be measured by the ATR method using a Fourier transform infrared spectrophotometer. Specifically, measurement is performed using polarized light as measurement light, and the crystallization index is calculated according to the following formula using the intensities of 1141 cm ^-1 and 1440 cm ^-1 of the obtained spectrum.

Crystallization Index=(I _C /I _R )

step,

I _C : Intensity of 1141 cm ^-1 when measured by incident light

_IR : Intensity of 1440 cm ^-1 when measured by incident light

am.

B-1-3. Insolubilization treatment, dyeing treatment and cross-linking treatment

If necessary, insolubilization treatment is performed after the air-assisted stretching treatment and before the underwater stretching treatment or the dyeing treatment. The insolubilization treatment is typically performed by immersing the PVA-based resin layer in an aqueous solution of boric acid. The dyeing treatment is typically performed by dyeing the PVA-based resin layer with a dichroic substance (typically iodine). If necessary, after the dyeing treatment, a crosslinking treatment is performed before the underwater stretching treatment. The crosslinking treatment is typically performed by immersing the PVA-based resin layer in an aqueous solution of boric acid. Details of the insolubilization treatment, dyeing treatment, and crosslinking treatment are described in, for example, Japanese Unexamined Patent Publication No. 2012-73580 or Japanese Patent No. 6470455 (above).

B-1-4. Underwater stretching treatment

The underwater stretching treatment is performed by immersing the laminate in a stretching bath. According to the underwater stretching treatment, stretching can be performed at a temperature lower than the glass transition temperature (typically about 80° C.) of the thermoplastic resin substrate or the PVA-based resin layer, and the PVA-based resin layer can be stretched at a high magnification while suppressing its crystallization. can As a result, a polarizing film having excellent optical properties can be manufactured.

Arbitrary suitable methods can be employed for the stretching method of the laminate. Specifically, fixed-end stretching or free-end stretching (for example, a method of uniaxially stretching a laminate by passing it between rolls having different circumferential speeds) may be used. Free end stretching is preferably selected. Stretching of the laminate may be performed in one step or in multiple steps. When performing in multiple steps, the draw ratio (maximum draw ratio) of the layered product described later is the product of the draw ratios of each step.

Stretching in water is preferably performed by immersing the layered product in an aqueous boric acid solution (stretching in boric acid water). By using a boric acid aqueous solution as the stretching bath, the PVA-based resin layer can be imparted with rigidity that can withstand the tension applied during stretching and water resistance that does not dissolve in water. Specifically, boric acid generates tetrahydroxyboric acid anions in an aqueous solution and can be crosslinked with PVA-based resins by hydrogen bonding. As a result, rigidity and water resistance can be imparted to the PVA-based resin layer so that it can be stretched satisfactorily, and a polarizing film having excellent optical properties can be manufactured.

The aqueous solution of boric acid is preferably obtained by dissolving boric acid and/or a borate salt in water as a solvent. The boric acid concentration is preferably 1 part by weight to 10 parts by weight, more preferably 2.5 parts by weight to 6 parts by weight, and particularly preferably 3 parts by weight to 5 parts by weight, based on 100 parts by weight of water. By setting the boric acid concentration to 1 part by weight or more, dissolution of the PVA-based resin layer can be effectively suppressed, and a polarizing film with higher characteristics can be manufactured. In addition to boric acid or borate salts, an aqueous solution obtained by dissolving boron compounds such as borax, glyoxal, glutaraldehyde, and the like in a solvent can also be used.

Preferably, iodide is incorporated into the stretching bath (boric acid aqueous solution). By blending iodide, elution of iodine adsorbed to the PVA-based resin layer can be suppressed. Specific examples of iodide are as described above. The concentration of iodide is preferably 0.05 parts by weight to 15 parts by weight, more preferably 0.5 parts by weight to 8 parts by weight, based on 100 parts by weight of water.

The stretching temperature (liquid temperature of the stretching bath) is preferably 40°C to 85°C, more preferably 60°C to 75°C. At such a temperature, it can be extended at a high magnification while suppressing dissolution of the PVA-based resin layer. Specifically, as described above, the glass transition temperature (Tg) of the thermoplastic resin substrate is preferably 60°C or higher in relation to the formation of the PVA-based resin layer. In this case, if the stretching temperature is lower than 40°C, there is a risk that satisfactory stretching may not be possible even if plasticization of the thermoplastic resin substrate by water is taken into consideration. On the other hand, as the temperature of the stretching bath becomes higher, the solubility of the PVA-based resin layer increases, and there is a possibility that excellent optical properties may not be obtained. The immersion time of the laminate in the stretching bath is preferably 15 seconds to 5 minutes.

The draw ratio by underwater stretching is preferably 1.5 times or more, more preferably 3.0 times or more. The total stretching ratio of the laminate is preferably 5.0 times or more, more preferably 5.5 times or more with respect to the original length of the laminate. By achieving such a high draw ratio, a polarizing film having extremely excellent optical properties can be manufactured. Such a high draw ratio can be achieved by employing an underwater stretching method (boric acid underwater stretching).

B-1-5. dry shrink treatment

The drying shrinkage treatment may be performed by zone heating performed by heating the entire zone, or may be performed by heating the conveying roll (using a so-called heating roll) (heating roll drying method). Preferably, both of them are used. By drying using a heating roll, heating curling of the layered product can be efficiently suppressed, and a polarizing film having an excellent appearance can be manufactured. Specifically, by drying in a state where the laminate is attached to a heating roll, the crystallization of the thermoplastic resin substrate can be efficiently promoted to increase the crystallinity, and even at a relatively low drying temperature, the crystallinity of the thermoplastic resin substrate can be increased satisfactorily. can As a result, the rigidity of the thermoplastic resin base material is increased, so that it can withstand contraction of the PVA-based resin layer due to drying, and curling is suppressed. In addition, since the laminate can be dried while maintaining a flat state by using a heating roll, not only curling but also occurrence of wrinkles can be suppressed. At this time, the optical properties can be improved by shrinking the laminate in the width direction by drying shrinkage treatment. This is because the orientation properties of PVA and PVA/iodine complexes can be effectively increased. The shrinkage in the width direction of the laminate by the drying shrinkage treatment is preferably 1% to 10%, more preferably 2% to 8%, and particularly preferably 4% to 6%. By using a heating roll, the laminate can be continuously contracted in the width direction while conveying, and high productivity can be realized.

1 is a schematic view showing an example of drying shrinkage treatment. In the drying shrinkage treatment, the laminate 200 is dried while being conveyed by conveyance rolls R1 to R6 and guide rolls G1 to G4 heated to a predetermined temperature. In the illustrated example, conveyance rolls R1 to R6 are arranged so that the surface of the PVA resin layer and the surface of the thermoplastic resin substrate are alternately and continuously heated. You may arrange|position conveyance roll R1-R6 so that only may be heated continuously.

Drying conditions can be controlled by adjusting the heating temperature of the conveying rolls (temperature of the heating rolls), the number of heating rolls, and the contact time with the heating rolls. The temperature of the heating roll is preferably 60°C to 120°C, more preferably 65°C to 100°C, and particularly preferably 70°C to 80°C. While the crystallinity of the thermoplastic resin can be increased satisfactorily and curling can be suppressed satisfactorily, an optical laminate having extremely excellent durability can be manufactured. In addition, the temperature of a heating roll can be measured with a contact thermometer. Although six conveyance rolls are provided in the illustrated example, the number of conveyance rolls is not particularly limited as long as there are a plurality of conveyance rolls. The conveyance rolls are usually 2 to 40, preferably 4 to 30. The contact time (total contact time) between the laminate and the heating roll is preferably 1 second to 300 seconds, more preferably 1 to 20 seconds, still more preferably 1 to 10 seconds.

The heating roll may be provided in a heating furnace (for example, an oven) or may be provided in a normal production line (in a room temperature environment). Preferably, it is provided in a heating furnace equipped with a blowing means. By using both heating roll drying and hot air drying, rapid temperature change between the heating rolls can be suppressed, and shrinkage in the width direction can be easily controlled. The temperature of hot air drying is preferably 30°C to 100°C. In addition, the hot air drying time is preferably 1 second to 300 seconds. The wind speed of the hot air is preferably about 10 m/s to 30 m/s. In addition, the said wind speed is the wind speed in a heating furnace, and can be measured with a mini-vane type digital anemometer.

B-1-6. other processing

Preferably, washing treatment is performed after the underwater stretching treatment and before the drying shrinkage treatment. The washing treatment is typically performed by immersing the PVA-based resin layer in an aqueous solution of potassium iodide.

As described above, a laminate of the thermoplastic resin substrate/polarizing film can be produced.

B-2. Staining of TAC film

Meanwhile, the TAC film is dyed with iodine. Dyeing can be done in any suitable fashion. Dyeing is performed, for example, by immersing a long TAC film in a dye solution (typically an aqueous solution of iodine) while conveying the roll. Dyeing is performed so that the transmittance at a wavelength of 400 nm of the dyed TAC film obtained is 65% or less and the Y-value transmittance is 80% or more. The transmittance and Y-value transmittance can be controlled by appropriately adjusting the iodine concentration of the iodine aqueous solution, the iodine aqueous solution temperature, and the dyeing time (immersion time). The iodine concentration of the iodine aqueous solution may change depending on the dyeing time (immersion time). The iodine concentration of the iodine aqueous solution is preferably 0.1% by weight or more, more preferably 0.5% by weight to 5.0% by weight, still more preferably 1.0% by weight to 3.0% by weight. If the iodine concentration is too low, a desired transmittance may not be obtained even if dyeing treatment is performed for a long time. The temperature of the iodine aqueous solution is preferably 20°C to 30°C. Dyeing time may vary depending on the iodine concentration of the iodine aqueous solution. Dyeing time is preferably 30 seconds or more, more preferably 50 seconds to 400 seconds. If the dyeing time is too short, the desired transmittance may not be obtained. On the other hand, unnecessarily lengthening the dyeing time is not effective considering production efficiency.

B-3. Fabrication of polarizer

The dyed TAC film obtained in the above B-2 is bonded to the surface of the polarizing film of the laminate of the thermoplastic resin substrate/polarizing film obtained in the above B-1 through an arbitrary appropriate adhesive agent. Examples of adhesives include water-based adhesives and active energy ray curable adhesives. In this way, a laminate of thermoplastic resin substrate/polarizing film/dyed TAC film can be produced. You may use this laminated body as a polarizing plate as it is. In this case, the thermoplastic resin substrate may function as an inner protective layer. Alternatively, the thermoplastic resin substrate may be peeled off from the laminate of thermoplastic resin substrate/polarizing film/dyed TAC film, and the laminate of dyed TAC film/polarizing film may be used as a polarizing plate. Alternatively, the thermoplastic resin substrate is peeled off from the laminate of the thermoplastic resin substrate/polarizing film/dyed TAC film, and the resin film is bonded to the peeled surface as an inner protective layer to obtain a laminate of the dyed TAC film/polarizing film/inner protective layer. You may use as a polarizing plate.

C. Polarizing plate with retardation layer

C-1. Overall configuration of polarizing plate with retardation layer

2 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to one embodiment of the present invention. The polarizing plate 100 with a retardation layer of this embodiment includes a polarizing plate 10 and a retardation layer 20 . The polarizing plate is the polarizing plate described in the above A-item and B-item. The polarizing plate 10 of the illustrated example includes a polarizing film 11, a viewer-side protective layer 12, and an inner protective layer 13. As described above, preferably, the inner protective layer 13 can be omitted. In a polarizing plate with a retardation layer, the retardation layer is typically disposed on the side opposite to the viewing side of the polarizing plate.

As shown in FIG. 3 , in the polarizing plate 101 with a retardation layer according to another embodiment, another retardation layer 50 and/or a conductive layer or an isotropic substrate 60 with a conductive layer may be provided. The other retardation layer 50 and the conductive layer or the isotropic substrate 60 with a conductive layer are typically provided on the side opposite to the polarizing plate 10 of the retardation layer 20 (the side opposite to the visible side). The other retardation layer typically exhibits a relationship of nz>nx=ny in refractive index characteristics. The other retardation layer 50 and the conductive layer or the isotropic substrate 60 with a conductive layer are typically provided in this order from the retardation layer 20 side. The other retardation layer 50 and the conductive layer or the isotropic substrate 60 with a conductive layer are typically arbitrary layers provided as needed, and any one or both of them may be omitted. For convenience, the phase difference layer 20 is sometimes referred to as a first phase difference layer and the other phase difference layer 50 is referred to as a second phase difference layer. In addition, when a conductive layer or an isotropic base material with a conductive layer is provided, the polarizing plate with a retardation layer is a so-called inner touch panel type input display device in which a touch sensor is built in between an image display cell (eg, an organic EL cell) and a polarizing plate. can be applied to

In the embodiment of the present invention, Re(550) of the first retardation layer 20 is 100 nm to 190 nm, and Re(450)/Re(550) is 0.8 or more and less than 1. Also, an angle between the slow axis of the first retardation layer 20 and the absorption axis of the polarizing film 11 is 40° to 50°.

The above embodiments may be appropriately combined, and changes obvious in the art may be added to the constituent elements in the above embodiments. For example, even if the configuration in which the isotropic substrate 60 with a conductive layer is provided on the outside of the second retardation layer 50 is replaced with an optically equivalent configuration (for example, a laminate of the second retardation layer and the conductive layer) do.

The polarizing plate with the retardation layer may further contain other retardation layers. Other optical characteristics of the retardation layer (eg, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, placement position, etc. may be appropriately set depending on the purpose.

The polarizing plate with the retardation layer may be in the form of a single sheet or in the form of a long picture. In the present specification, "elongated shape" means an elongate shape having a length that is sufficiently long with respect to the width, and includes, for example, an elongate shape in which the length is 10 times or more, preferably 20 times or more, with respect to the width. A long polarizing plate with a retardation layer can be wound in a roll shape. When the polarizing plate with the retardation layer is long, the polarizing plate and the retardation layer are also long. In this case, the polarizing film preferably has an absorption axis in a long direction. The first retardation layer is preferably an obliquely stretched film having a slow axis in a direction forming an angle of 40° to 50° with respect to a long direction. If the polarizing film and the 1st retardation layer are such a structure, a polarizing plate with a retardation layer can be produced by roll-to-roll.

Practically, an adhesive layer (not shown) is provided on the side opposite to the polarizing plate of the retardation layer, and the polarizing plate with the retardation layer can be attached to the image display cell. Moreover, it is preferable that the release film is temporarily attached to the surface of the pressure-sensitive adhesive layer until the polarizing plate with the retardation layer is put into use. Roll formation becomes possible while protecting an adhesive layer by temporarily attaching a peeling film.

The total thickness of the polarizing plate with the retardation layer is preferably 140 μm or less, more preferably 120 μm or less, still more preferably 100 μm or less, even more preferably 90 μm or less, still more preferably 85 μm or less. The lower limit of the total thickness may be, for example, 80 μm. According to the embodiment of the present invention, such an extremely thin polarizing plate with a retardation layer can be realized. Such a polarizing plate with a retardation layer can have extremely excellent flexibility and bending durability. Such a polarizing plate with a retardation layer can be particularly suitably applied to a curved image display device and/or a curved or bendable image display device. In addition, the total thickness of the polarizing plate with a retardation layer refers to the total thickness of all layers constituting the polarizing plate with a retardation layer, excluding the pressure-sensitive adhesive layer for adhering the polarizing plate with the retardation layer to an external adherend such as a panel or glass ( That is, the total thickness of the polarizing plate with a retardation layer does not include the thickness of the pressure-sensitive adhesive layer for bonding the polarizing plate with a retardation layer to an adjacent member such as an image display cell and the peeling film that can be temporarily attached to the surface).

Hereinafter, the 1st retardation layer, the 2nd retardation layer, and a conductive layer or the isotropic base material with a conductive layer are demonstrated concretely. Moreover, the 1st retardation layer may be an orientation fixation layer of a liquid crystal compound (hereinafter referred to as a liquid crystal orientation fixation layer). The liquid crystal alignment hardening layer is described in section C-4 as a modified example of the first retardation layer.

C-2. 1st retardation layer

The first retardation layer 20 may have any appropriate optical and/or mechanical properties depending on the purpose. The first retardation layer 20 typically has a slow axis. In one embodiment, the angle θ between the slow axis of the first retardation layer 20 and the absorption axis of the polarizing film 11 is 40 ° to 50 ° as described above, preferably 42 ° to 48 °, More preferably, it is about 45 degrees. When the angle θ is within this range, a polarizing plate with a retardation layer having extremely excellent circular polarization characteristics (as a result, excellent antireflection characteristics) can be obtained by using a λ/4 plate as the first retardation layer as described later.

The first retardation layer preferably has a refractive index characteristic of nx > ny > nz. The first retardation layer is typically provided to impart antireflection properties to the polarizing plate, and in one embodiment, it can function as a λ/4 plate. In this case, the in-plane retardation Re (550) of the first retardation layer is 100 nm to 190 nm as described above, preferably 110 nm to 170 nm, and more preferably 130 nm to 160 nm. In addition, 'ny=nz' here includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, there may be cases where ny<nz is satisfied within a range that does not impair the effects of the present invention.

The Nz coefficient of the first retardation layer is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3. By satisfying such a relationship, when the obtained polarizing plate with a retardation layer is used for an image display device, very excellent reflection color can be achieved.

The first retardation layer may exhibit reverse dispersion wavelength characteristics in which the retardation value increases with the wavelength of the measurement light, or may exhibit positive wavelength dispersion characteristics in which the retardation value decreases with the wavelength of the measurement light. It may exhibit flat wavelength dispersion characteristics that hardly change even with the wavelength of light. In one embodiment, the first retardation layer exhibits reverse dispersion wavelength characteristics. In this case, Re(450)/Re(550) of the retardation layer is 0.8 or more and less than 1, as described above, and is preferably 0.8 or more and 0.95 or less. With such a configuration, very excellent antireflection characteristics can be realized.

The absolute value of the photoelastic coefficient of the first retardation layer is preferably 2×10 ⁻¹¹ m ² /N or less, more preferably 2.0×10 ⁻¹³ m ² /N to 1.5× ^{10 −11} m ² /N, and still more Preferably, it contains a resin of 1.0×10 ^-12 m ² /N to 1.2× ^{10 -11} m ² /N. If the absolute value of the photoelastic coefficient is in this range, phase difference change is unlikely to occur when shrinkage stress occurs during heating. As a result, heat unevenness of the resulting image display device can be favorably prevented.

The first retardation layer is typically composed of a stretched film of a resin film. The thickness of the first retardation layer is preferably 70 μm or less, more preferably 45 μm to 60 μm. When the thickness of the first retardation layer is in such a range, curling at the time of bonding can be favorably controlled while suppressing curling at the time of heating favorably.

The first retardation layer 20 may be formed of any suitable resin film that can satisfy the above characteristics. Representative examples of such resins include polycarbonate-based resins, polyester carbonate-based resins, polyester-based resins, polyvinyl acetal-based resins, polyarylate-based resins, cyclic olefin-based resins, cellulose-based resins, polyvinyl alcohol-based resins, Polyamide-based resins, polyimide-based resins, polyether-based resins, polystyrene-based resins, and acrylic resins are exemplified. These resins may be used alone or in combination (for example, blend or copolymerization). When the first retardation layer is composed of a resin film exhibiting reverse dispersion wavelength characteristics, a polycarbonate-based resin or a polyester carbonate-based resin (hereinafter sometimes simply referred to as a polycarbonate-based resin) can be suitably used.

As the polycarbonate-based resin, any appropriate polycarbonate-based resin can be used as long as the effects of the present invention are obtained. For example, the polycarbonate-based resin includes a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and an alicyclic diol, alicyclic dimethanol, di, tri, or polyethylene. and structural units derived from glycols and at least one dihydroxy compound selected from the group consisting of alkylene glycols or spiroglycols. Preferably, the polycarbonate-based resin comprises a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, a structural unit derived from alicyclic dimethanol, and/or contains structural units derived from di, tri or polyethylene glycol; More preferably, a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from di, tri, or polyethylene glycol are included. The polycarbonate-based resin may contain structural units derived from other dihydroxy compounds as needed. Further, details of a polycarbonate-based resin that can be suitably used for the first retardation layer and a method of forming the first retardation layer are, for example, Japanese Unexamined Patent Publication No. 2014-10291, Japanese Unexamined Patent Publication No. 2014-26266, It describes in Unexamined-Japanese-Patent No. 2015-212816, Unexamined-Japanese-Patent No. 2015-212817, and Unexamined-Japanese-Patent No. 2015-212818, and description of these publications is integrated in this specification as a reference.

C-3. Second retardation layer

As described above, the second retardation layer may be a so-called positive C plate having a refractive index characteristic of nz>nx=ny. By using the positive C plate as the second retardation layer, it is possible to favorably prevent reflection in an oblique direction, and a wide viewing angle of the antireflection function becomes possible. In this case, the phase difference Rth (550) in the thickness direction of the second retardation layer is preferably -50 nm to -300 nm, more preferably -70 nm to -250 nm, still more preferably -90 nm to -200 nm, particularly preferably -100nm to -180nm. Here, 'nx=ny' includes not only a case where nx and ny are strictly equal, but also a case where nx and ny are substantially equal. That is, the in-plane retardation Re (550) of the second retardation layer may be less than 10 nm.

The second retardation layer having a refractive index characteristic of nz>nx=ny may be formed of any suitable material. The second retardation layer preferably includes a film containing a liquid crystal material fixed in a homeotropic orientation. The liquid crystal material (liquid crystal compound) capable of homeotropic alignment may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method for forming the retardation layer include the liquid crystal compound described in [0020] to [0028] of Japanese Unexamined Patent Publication No. 2002-333642 and the method for forming the retardation layer. In this case, the thickness of the second retardation layer is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 8 μm, still more preferably 0.5 μm to 5 μm.

C-4. Modification of the first retardation layer

The first retardation layer 20 may have a laminated structure of a first liquid crystal alignment fixed layer and a second liquid crystal alignment fixed layer. In this case, either one of the 1st liquid-crystal orientation fixed layer and the 2nd liquid-crystal orientation fixed layer can function as a lambda/4 plate, and the other can function as a lambda/2 plate. Accordingly, the thickness of the first liquid crystal alignment fixed layer and the second liquid crystal alignment fixed layer can be adjusted so as to obtain a desired in-plane retardation of the λ/4 plate or the λ/2 plate. For example, when the first liquid crystal alignment fixed layer functions as a λ/2 plate and the second liquid crystal alignment fixed layer functions as a lambda/4 plate, the thickness of the first liquid crystal alignment fixed layer is, for example, 2.0 μm to 3.0 μm, The thickness of the 2nd liquid-crystal orientation hardening layer is 1.0 micrometer - 2.0 micrometer, for example. In this case, the in-plane retardation Re (550) of the first liquid crystal alignment fixed layer is preferably 200 nm to 300 nm, more preferably 230 nm to 290 nm, still more preferably 250 nm to 280 nm. The in-plane retardation Re (550) of the second liquid crystal alignment hardened layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, still more preferably 130 nm to 160 nm. The angle formed by the slow axis of the first liquid crystal alignment solidified layer and the absorption axis of the polarizing film is preferably 10° to 20°, more preferably 12° to 18°, still more preferably about 15°. The angle formed by the slow axis of the second liquid crystal alignment solidified layer and the absorption axis of the polarizing film is preferably 70° to 80°, more preferably 72° to 78°, still more preferably about 75°. With such a configuration, it is possible to obtain characteristics close to ideal reverse wavelength dispersion characteristics, and as a result, extremely excellent antireflection characteristics can be realized. Both of the 1st liquid-crystal orientation fixed layer and the 2nd liquid-crystal orientation fixed layer typically show the relationship of nx>ny=nz in a refractive index characteristic. The Nz coefficient of the first liquid crystal alignment fixed layer and the second liquid crystal alignment fixed layer is preferably 0.9 to 1.5, more preferably 0.9 to 1.3. The liquid crystal compounds constituting the first liquid crystal alignment fixed layer and the second liquid crystal alignment fixed layer, and the method for forming the first liquid crystal alignment fixed layer and the second liquid crystal alignment fixed layer are described in, for example, Japanese Unexamined Patent Publication No. 2006-163343 has been The description of the publication is incorporated herein by reference. In addition, when the first retardation layer has such a stacked structure, the second retardation layer can typically be omitted.

C-5. Conductive layer or isotropic substrate with conductive layer

The conductive layer can be formed by forming a metal oxide film on any suitable substrate by any suitable film formation method (eg, vacuum deposition method, sputtering method, CVD method, ion plating method, spray method, etc.). Examples of the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Among them, indium-tin composite oxide (ITO) is preferred.

When the conductive layer contains a metal oxide, the thickness of the conductive layer is preferably 50 nm or less, more preferably 35 nm or less. The lower limit of the thickness of the conductive layer is preferably 10 nm.

The conductive layer may be transferred from the substrate to the first retardation layer (or, if present, the second retardation layer), and the conductive layer alone may become a component layer of the polarizing plate with a retardation layer, or a laminate with the substrate (with a conductive layer) substrate) may be laminated on the first retardation layer (or the second retardation layer if present). Preferably, the substrate is optically isotropic, and therefore the conductive layer can be used for a polarizing plate with a retardation layer as an isotropic substrate with a conductive layer.

As the optically isotropic substrate (isotropic substrate), any suitable isotropic substrate can be employed. As the material constituting the isotropic base material, for example, a material whose main skeleton is a resin without a conjugated system such as norbornene resin or olefin resin, and a cyclic structure such as a lactone ring or glutarimide ring in the main chain of an acrylic resin. Materials etc. are mentioned. When such a material is used, when an isotropic substrate is formed, the expression of phase difference accompanying orientation of molecular chains can be suppressed to a small level. The thickness of the isotropic substrate is preferably 50 μm or less, and more preferably 35 μm or less. The lower limit of the thickness of the isotropic substrate is, for example, 20 µm.

The conductive layer and/or the conductive layer of the isotropic substrate with a conductive layer may be patterned as needed. By patterning, a conductive portion and an insulating portion can be formed. As a result, electrodes can be formed. The electrodes may function as touch sensor electrodes that detect contact with the touch panel. As the patterning method, any suitable method can be employed. Specific examples of the patterning method include a wet etching method and a screen printing method.

D. Image display device

The polarizing plate described in the above items A and B or the polarizing plate with a retardation layer described in the above item C can be applied to an image display device. Accordingly, embodiments of the present invention include an image display device using such a polarizing plate or a polarizing plate with a retardation layer. Representative examples of the image display device include a liquid crystal display device and an electroluminescence (EL) display device (eg, an organic EL display device and an inorganic EL display device). An image display device according to an embodiment of the present invention includes a polarizing plate or a polarizing plate with a retardation layer on its viewing side. Polarizing plates with a retardation layer are laminated so that the retardation layer is on the side of an image display cell (for example, a liquid crystal cell, an organic EL cell, or an inorganic EL cell) (a polarizing film is on the viewing side). In one embodiment, the image display device includes a curved shape (actually, a curved display screen) and/or is bendable or bendable. By using the above polarizing plate or polarizing plate with a retardation layer, the reflected color of the image display device can be made close to neutral. Therefore, according to an embodiment of the present invention, an image adjustment method of such an image display device can also be provided.

[Example]

Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited by these examples. The measurement method of each characteristic is as follows. In addition, unless otherwise specified, 'parts' and '%' in Examples and Comparative Examples are based on weight.

(1) Thickness

The thickness of 10 µm or less was measured using an interference film thickness meter (manufactured by Otsuka Electronics, product name 'MCPD-3000'). The thickness exceeding 10 μm was measured using a digital micrometer (manufactured by Anritz, product name 'KC-351C').

(2) single transmittance and degree of polarization

For the polarizing plates used in Examples and Comparative Examples, single transmittance (Ts), parallel transmittance (Tp), and orthogonal transmittance (Tc) measured using an ultraviolet / visible ray spectrophotometer (V-7100 manufactured by Nippon Bunko Co., Ltd.) Ts, Tp, and Tc of the polarizing film were respectively used. These Ts, Tp, and Tc are Y values measured by a JIS Z8701 2-degree field of view (C light source) and corrected for visibility. In addition, the protective layer of the light plate used in Examples and Comparative Examples included a hard coat (HC) layer on the surface, and the refractive index of the protective layer was 1.50, and the refractive index of the HC layer was 1.53. In addition, the refractive index of the surface of the polarizing film opposite to the protective layer was 1.53.

Polarization degree P was calculated|required by the following formula from the obtained Tp and Tc.

Degree of polarization P(%)={(Tp-Tc)/(Tp+Tc)} ^1/2 × 100

In addition, as for the spectrophotometer, the Otsuka Electronics Co., Ltd. product LPF-200 etc. can perform equivalent measurement.

The transmittance is a value when the refractive index of the surface is 1.50/1.53 in both cases of the transmittance of the protective layer and the transmittance of the polarizing plate, and when the combination of the surface refractive indices of the measurement configuration is different from this, the change in the surface refractive index results in the air interface. Theoretical correction was performed from the magnitude of the change amount of reflection (surface reflection). For example, when measuring the configuration of a TAC/polarizing film with an HC layer (with a transmittance of 40%), the combination of surface refractive indices is 1.53/1.53, so by setting the measured value +0.2%, the transmittance of the polarizing plate at 1.50/1.53 can be converted. do. The transmittance of the TAC film alone with the HC layer was not corrected because the combination of refractive indices was 1.50/1.53.

(3) frontal reflection color

The polarizing plate with the retardation layer obtained in Examples and Comparative Examples was prepared by using an acrylic adhesive having no UV absorbing function and using a reflecting plate (manufactured by Toray Film Co., Ltd., trade name 'DMS-X42'; reflectance 86%, reflective color without a polarizer a ^* = -0.22, b ^* = 0.32) to prepare measurement samples. At this time, it bonded so that the retardation layer side of the polarizing plate with a retardation layer may face a reflector. For the sample to be measured, it is measured by the SCE method using a spectrophotometer (CM-2600d manufactured by Konica Minolta), and the values of a ^* and b ^* are substituted into √ (a ^{* 2} + b ^{* 2} ) to obtain frontal reflection color was obtained.

[Example 1-1]

1. Fabrication of polarizing film

As the thermoplastic resin substrate, an amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a long shape, water absorption of 0.75%, and Tg of about 75° C. was used. Corona treatment was performed on one side of the resin substrate.

Polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name 'Gosefimer Z410') were mixed in a ratio of 9:1 to 100 parts by weight of a PVA-based resin containing potassium iodide 13 Part by weight was added and dissolved in water to prepare a PVA aqueous solution (coating liquid).

A laminate was produced by applying the PVA aqueous solution to the corona-treated surface of the resin substrate and drying at 60° C. to form a PVA-based resin layer having a thickness of 13 μm.

The obtained layered product was uniaxially stretched at the free end by 2.4 times in the machine direction (longitudinal direction) between rolls having different circumferential speeds in an oven at 130°C (air assisted stretching treatment).

Next, the laminate was immersed in an insolubilization bath (boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insolubilization treatment).

Subsequently, the dyeing bath (iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with respect to 100 parts by weight of water) at a liquid temperature of 30 ° C. is added so that the single transmittance (Ts) of the finally obtained polarizing film becomes a desired value. It was immersed for 60 seconds while adjusting the concentration (dyeing treatment).

Then, it was immersed in a crosslinking bath (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (crosslinking treatment).

Thereafter, while immersing the layered product in an aqueous solution (boric acid concentration: 4.0% by weight, potassium iodide: 5.0% by weight) at a liquid temperature of 70°C, 1 Axial stretching was performed (underwater stretching treatment).

Thereafter, the laminate was immersed in a washing bath (aqueous solution obtained by blending 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 20°C (washing treatment).

Thereafter, while drying in an oven maintained at 90°C, it was brought into contact with a heating roll made of SUS whose surface temperature was maintained at 75°C for about 2 seconds (dry shrinkage treatment). The shrinkage rate in the width direction of the layered product by the drying shrinkage treatment was 5.2%.

In this way, a polarizing film having a thickness of 5 μm was formed on the resin substrate.

2. Staining of TAC film

A dyeing bath with a liquid temperature of 25°C ( It was immersed in an iodine aqueous solution having an iodine concentration of 1.0% by weight). The immersion time was 60 seconds. The transmittance at a wavelength of 400 nm of the obtained dyed TAC film was 59.8%, and the transmittance Y value was 90.1%.

3. Fabrication of polarizer

The dyed TAC film with the HC layer obtained in 2. above was bonded to the surface of the polarizing film obtained in 1. above (on the side opposite to the resin substrate) via an ultraviolet curable adhesive. Specifically, the coating was applied so that the total thickness of the curable adhesive was 1.0 μm, and bonding was performed using a roll machine. After that, UV rays were irradiated from the TAC film side to cure the adhesive. Next, after slitting both ends, the resin substrate was peeled off to obtain a long polarizing plate (width: 1300 mm) having a configuration of protective layer (dyed TAC film)/adhesive layer/polarizing film. The single transmittance of the polarizing plate (actually, the polarizing film) was 43.0%, and the degree of polarization was 99.995%.

4. Production of retardation film constituting the retardation layer

4-1. Polymerization of polyester carbonate resin

Polymerization was carried out using a batch polymerization apparatus including two vertical reactors equipped with stirring blades and a reflux condenser controlled at 100°C. Bis [9- (2-phenoxycarbonylethyl) fluoren-9-yl] methane 29.60 parts by mass (0.046 mol), isosorbide (ISB) 29.21 parts by mass (0.200 mol), spiroglycol (SPG) 42.28 mass part (0.139 mol), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC), and 1.19 × 10 ^-2 parts by mass (6.78 × 10 ^-5 mol) of calcium acetate monohydrate as a catalyst were charged. After replacing the inside of the reactor with reduced pressure nitrogen, heating was performed with a heating medium, and stirring was started when the internal temperature reached 100°C. 40 minutes after the start of temperature increase, the internal temperature reached 220°C, and while controlling to maintain this temperature, pressure reduction was started, and after reaching 220°C, it was set to 13.3 kPa in 90 minutes. Phenol vapor, which is a by-product of the polymerization reaction, is directed to a reflux condenser at 100°C, a small amount of monomer components contained in the phenol vapor are returned to the reactor, and uncondensed phenol vapor is directed to a condenser at 45°C for recovery. did After nitrogen was introduced into the first reactor to once restore the pressure to atmospheric pressure, the oligomerized reaction solution in the first reactor was transferred to the second reactor. Subsequently, the temperature increase and pressure reduction in the second reactor were started, and the internal temperature was 240°C and the pressure was 0.2 kPa in 50 minutes. Thereafter, polymerization was allowed to proceed until a predetermined agitation power was reached. When the predetermined power was reached, nitrogen was introduced into the reactor to restore pressure, the resulting polyester carbonate-based resin was extruded into water, and the strands were cut to obtain pellets.

4-2. Production of retardation film

After vacuum drying the obtained polyester carbonate-based resin (pellet) at 80 ° C. for 5 hours, a single screw extruder (manufactured by Toshiba Machinery Co., Ltd., cylinder set temperature: 250 ° C.), T die (width 200 mm, set temperature: 250 ° C.), A long resin film with a thickness of 135 μm was produced using a film forming apparatus equipped with a chilled roll (set temperature: 120 to 130° C.) and a winder. The obtained long resin film was stretched in the width direction at a stretching temperature of 133°C and a stretching ratio of 2.8 to obtain a retardation film having a thickness of 48 µm. Re(550) of the obtained retardation film was 144 nm, Re(450)/Re(550) was 0.82, and the Nz coefficient was 1.12.

5. Production of Polarizing Plate with Retardation Layer

The retardation film obtained in the above 4. was bonded to the surface of the polarizing film of the polarizing plate obtained in the above 3. through an acrylic pressure-sensitive adhesive (thickness: 5 µm). At this time, they were bonded together so that the absorption axis of the polarizing film and the slow axis of the retardation film formed an angle of 45°. In this way, a polarizing plate with a phase difference layer having a configuration of protective layer/adhesive layer/polarizing film/adhesive layer/phase difference layer was obtained. The total thickness of the obtained polarizing plate with a retardation layer was 84 µm. The obtained polarizing plate with a retardation layer was used for evaluation of the above (3). Results are shown in Table 1.

[Example 1-2]

The TAC film was dyed in the same manner as in Example 1-1 except that the dyeing time was 120 seconds. The transmittance at a wavelength of 400 nm of the obtained dyed TAC film was 52.8%, and the transmittance Y value was 89.2%. Except having used this dyeing TAC film, it carried out similarly to Example 1-1, and produced the polarizing plate with a retardation layer. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1-1. The results are shown in Table 1.

[Example 1-3]

The TAC film was dyed in the same manner as in Example 1-1 except that the dyeing time was 300 seconds. The transmittance at a wavelength of 400 nm of the obtained dyed TAC film was 31.9%, and the transmittance Y value was 88.4%. Except having used this dyeing TAC film, it carried out similarly to Example 1-1, and produced the polarizing plate with a retardation layer. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1-1. The results are shown in Table 1.

[Comparative Example 1]

A polarizing plate with a retardation layer was produced in the same manner as in Example 1-1 except for using an unstained TAC film. The transmittance of the undyed TAC film at a wavelength of 400 nm was 68.5%, and the transmittance Y value was 92.1%. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1-1. The results are shown in Table 1.

[Example 2-1]

A polarizing film having a single transmittance of 44.0% was prepared by adjusting dyeing conditions. Except having used this polarizing film, it carried out similarly to Example 1-1, and produced the polarizing plate with a retardation layer. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1-1. The results are shown in Table 1.

[Example 2-2]

Except having used the polarizing film produced in Example 2-1, it carried out similarly to Example 1-2, and produced the polarizing plate with a retardation layer. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1-1. The results are shown in Table 1.

[Example 2-3]

Except having used the polarizing film produced in Example 2-1, it carried out similarly to Example 1-3, and produced the polarizing plate with a retardation layer. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1-1. The results are shown in Table 1.

[Comparative Example 2]

A polarizing plate with a retardation layer was produced in the same manner as in Comparative Example 1 except for using the polarizing film produced in Example 2-1. The obtained polarizing plate with a retardation layer was subjected to the same evaluation as in Example 1-1. The results are shown in Table 1.

[Table 1]

[evaluation]

As is clear from Table 1, according to the embodiment of the present invention, by using a dyed TAC film as a protective layer, the reflected color can be made closer to a neutral state than the comparative example.

The polarizing plate with a retardation layer of the present invention is preferably used as a circularly polarizing plate for liquid crystal display devices, organic EL display devices, and inorganic EL display devices.

10 polarizer
11 polarizer
12 Viewer side protective layer
13 inner protective layer
20 phase difference layer
100 Polarizer with retardation layer
101 Polarizing plate with retardation layer

Claims (15)

A dyed triacetyl cellulose film that is dyed with iodine, has a transmittance of 65% or less at a wavelength of 400 nm, and a transmittance Y obtained by correcting visibility of 80% or more. A polarizing film and a protective layer disposed on at least one side of the polarizing film,
The thickness of the polarizing film is 8 μm or less,
A polarizing plate in which the protective layer is composed of the dyed triacetyl cellulose film according to claim 1. Forming a polyvinyl alcohol-based resin layer on one side of a long thermoplastic resin substrate to form a laminate,
Applying dyeing treatment and stretching treatment to the laminate to make the polyvinyl alcohol-based resin layer a polarizing film;
Dyeing the triacetyl cellulose film with iodine to obtain a transmittance of 65% or less at a wavelength of 400 nm and a transmittance Y corrected for visibility of 80% or more, and
Bonding the dyed triacetyl cellulose film to the polarizing film
The manufacturing method of the polarizing plate of Claim 2 containing a. According to claim 3,
The dyeing method of producing a polarizing plate comprising immersing the triacetyl cellulose film in an iodine aqueous solution having an iodine concentration of 0.1% by weight or more. It includes the polarizing plate according to claim 2 and a retardation layer disposed on a side opposite to the viewing side of the polarizing plate,
Re (550) of the retardation layer is 100 nm to 190 nm, Re (450) / Re (550) is 0.8 or more and less than 1,
The angle between the slow axis of the retardation layer and the absorption axis of the polarizing film of the polarizing plate is 40 ° to 50 °,
A polarizing plate with a retardation layer. According to claim 5,
The polarizing plate with a retardation layer in which the said retardation layer is comprised from a polycarbonate-type resin film. According to claim 5,
The polarizing plate with the retardation layer further includes another retardation layer outside the retardation layer, wherein the refractive index characteristic of the other retardation layer exhibits a relationship of nz>nx=ny. According to claim 5,
It is long,
The polarizing film has an absorption axis in a long direction,
The retardation layer is an obliquely stretched film having a slow axis in a direction forming an angle of 40 ° to 50 ° with respect to the long direction,
A polarizing plate with a retardation layer. According to claim 8,
A polarizing plate with a retardation layer that can be wound into a roll. It includes the polarizing plate according to claim 2 and a retardation layer disposed on a side opposite to the viewing side of the polarizing plate,
The retardation layer has a laminated structure of an alignment-fixed layer of a first liquid crystal compound and an alignment-fixed layer of a second liquid crystal compound,
Re (550) of the alignment hardening layer of the first liquid crystal compound is 200 nm to 300 nm, and the angle formed by the slow axis and the absorption axis of the polarizing film is 10 ° to 20 °,
Re (550) of the alignment hardening layer of the second liquid crystal compound is 100 nm to 190 nm, and the angle between its slow axis and the absorption axis of the polarizing film is 70 ° to 80 °,
A polarizing plate with a retardation layer. According to claim 5,
A polarizing plate with a retardation layer further comprising a conductive layer or an isotropic base material with a conductive layer on the outside of the retardation layer. An image display device comprising the polarizing plate according to claim 2. An image display device comprising the polarizing plate with a retardation layer according to claim 5. According to claim 12 or 13,
An image display device that is an organic electroluminescent display device or an inorganic electroluminescent display device. An image display device comprising bonding the polarizing plate according to claim 2 or the polarizing plate with a retardation layer according to any one of claims 5 to 11 to the viewing side of an image display cell to bring the reflected color closer to neutral Image adjustment method.