TW202129316A - Polarizing plate and phase difference layer-equipped polarizing plate, and image display device using same - Google Patents

Abstract

Provided are a thin-type polarizing plate and a phase difference layer-equipped polarizing plate that have excellent durability under a high temperature and high humidity environment. The polarizing plate according to the present invention has a polarizer, an iodine transmission suppression layer, and an adhesive layer in this order. The iodine presence index of the adhesive layer is not more than 0.050. The phase difference layer-equipped polarizing plate according to the present invention has this polarizing plate and a phase difference layer that is disposed between the polarizer and the adhesive layer. The phase difference layer is a liquid crystal compound oriented solidification layer having a circular polarization function or an elliptical polarization function.

Description

Polarizing plate and polarizing plate with retardation layer and image display device using them

The present invention relates to a polarizing plate, a polarizing plate with a retardation layer, and an image display device using them.

In recent years, image display devices represented by liquid crystal display devices and electroluminescence (EL) display devices (for example, organic EL display devices and inorganic EL display devices) have rapidly spread. The image display device represents the use of polarizers and phase difference plates. In practical applications, polarizing plates with retardation layers formed by integrating a polarizing plate and a retardation plate are widely used (for example, Patent Document 1). Recently, as the demand for thinning of image display devices has increased, there has been an increasing demand for polarizing plates and The demand for thinner polarizers with retardation layers has also increased. However, thin polarizers and polarizers with retardation layers have the problem of large changes in optical characteristics (representatively, polarization) under high temperature and high humidity environments, and insufficient durability. Prior art literature Patent literature

Patent Document 1: Japanese Patent No. 3325560

The problem to be solved by the invention The present invention was made to solve the above-mentioned problems in the past, and its main purpose is to provide a thin polarizing plate and a polarizing plate with a retardation layer that have excellent durability in a high-temperature and high-humidity environment.

(式中，X表示包含反應性基之官能基，且該反應性基係選自於由乙烯基、(甲基)丙烯醯基、苯乙烯基、(甲基)丙烯醯胺基、乙烯基醚基、環氧基、氧雜環丁烷基、羥基、胺基、醛基及羧基所構成群組中之至少1種反應性基，R¹ 及R² 分別獨立表示氫原子、可具有取代基之脂肪族烴基、可具有取代基之芳基或可具有取代基之雜環基，R¹ 及R² 可相互連結形成環)。 根據本發明另一面向提供一種附相位差層之偏光板。該附相位差層之偏光板具有上述偏光板及配置於上述偏光件與上述黏著劑層之間的相位差層。該相位差層係具有圓偏光機能或楕圓偏光機能之液晶化合物的定向固化層。 在一實施形態中，上述相位差層為單一層，且該相位差層的Re(550)為100nm~190nm，該相位差層之慢軸與上述偏光件之吸收軸形成之角度為40°~50°。 在一實施形態中，上述相位差層具有第1液晶化合物之定向固化層與第2液晶化合物之定向固化層的積層結構；該第1液晶化合物之定向固化層的Re(550)為200nm~300nm，且其慢軸與上述偏光件之吸收軸形成之角度為10°~20°；該第2液晶化合物之定向固化層的Re(550)為100nm~190nm，且其慢軸與該偏光件之吸收軸形成之角度為70°~80°。 在一實施形態中，上述附相位差層之偏光板的總厚度在60μm以下。 根據本發明又另一面向提供一種影像顯示裝置。該影像顯示裝置具備上述偏光板或附相位差層之偏光板。 在一實施形態中，上述影像顯示裝置係有機電致發光顯示裝置或無機電致發光顯示裝置。Means for Solving the Problem The polarizing plate of the present invention has a polarizer, an iodine permeation suppression layer, and an adhesive layer in this order. The iodine presence index of the adhesive layer is 0.050 or less. In one embodiment, the cured product or thermosetting product of the coating film of the organic solvent solution of the above-mentioned iodine permeation suppression layer resin. In one embodiment, the glass transition temperature of the resin constituting the iodine permeation suppression layer is 85° C. or higher, and the weight average molecular weight Mw is 25,000 or higher. In one embodiment, the iodine permeation suppression layer is provided with two or more layers between the polarizer and the adhesive layer. In one embodiment, the thickness of the iodine permeation suppression layer is 0.05 μm-10 μm. In one embodiment, the resin constituting the iodine permeation inhibiting layer includes a copolymer obtained by polymerizing a monomer mixture, and the monomer mixture includes more than 50 parts by weight of a (meth)acrylic monomer and more than 0 parts by weight. Parts by weight and less than 50 parts by weight of the monomer represented by formula (1): [Chemical formula 1]

(In the formula, X represents a functional group containing a reactive group, and the reactive group is selected from the group consisting of vinyl, (meth)acryloyl, styryl, (meth)acrylamido, vinyl At least one reactive group in the group consisting of ether group, epoxy group, oxetanyl group, hydroxyl group, amino group, aldehyde group and carboxyl group, R ¹ and R ² each independently represent a hydrogen atom and may have substitution The aliphatic hydrocarbon group of the group, the aryl group which may have a substituent, or the heterocyclic group which may have a substituent, R ¹ and R ² may be connected to each other to form a ring). According to another aspect of the present invention, a polarizing plate with a retardation layer is provided. The polarizing plate with retardation layer has the polarizing plate and a retardation layer arranged between the polarizer and the adhesive layer. The retardation layer is a directional solidified layer of a liquid crystal compound with a circular polarization function or an elliptical polarization function. In one embodiment, the retardation layer is a single layer, and the Re(550) of the retardation layer is 100nm~190nm, and the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizer is 40°~ 50°. In one embodiment, the above-mentioned retardation layer has a laminated structure of an oriented solidified layer of a first liquid crystal compound and an oriented solidified layer of a second liquid crystal compound; the Re(550) of the oriented solidified layer of the first liquid crystal compound is 200nm~300nm And the angle formed by the slow axis and the absorption axis of the polarizer is 10°~20°; the Re (550) of the oriented curing layer of the second liquid crystal compound is 100nm~190nm, and the slow axis and the polarizer The angle formed by the absorption axis is 70°~80°. In one embodiment, the total thickness of the polarizing plate with retardation layer is 60 μm or less. According to yet another aspect of the present invention, an image display device is provided. The image display device includes the above-mentioned polarizing plate or a polarizing plate with a retardation layer. In one embodiment, the above-mentioned image display device is an organic electroluminescence display device or an inorganic electroluminescence display device.

Invention effect According to the embodiment of the present invention, by providing a specific iodine permeation suppression layer to control the iodine presence index of the adhesive layer, a thin polarizing plate with excellent durability under high temperature and high humidity environments and a polarizing plate with retardation layer can be realized. The cured product or thermosetting product of the coating film of the organic solvent solution of the iodine permeation inhibiting layer resin that can be used in the embodiment of the present invention, the glass transition temperature of the resin constituting the iodine permeation inhibiting layer is 85°C or higher, and the weight average molecular weight Mw is 25000 or more, and the iodine presence index of the adhesive layer of the embodiment of the present invention is 0.050 or less.

The following describes embodiments of the present invention, but the present invention is not limited by these embodiments.

(Definition of terms and symbols) The definitions of terms and symbols in this manual are as follows. (1) Refractive index (nx, ny, nz) "Nx" is the refractive index in the direction where the in-plane refractive index is the largest (that is, the slow axis direction), "ny" is the refractive index in the direction orthogonal to the slow axis (that is, the fast axis direction) in the plane, and " nz" is the refractive index in the thickness direction. (2) In-plane phase difference (Re) "Re(λ)" is the in-plane phase difference measured with light of wavelength λnm at 23°C. For example, "Re(550)" is the in-plane phase difference measured with light with a wavelength of 550nm 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 thickness direction retardation measured with light of wavelength λnm at 23°C. For example, "Rth(550)" is the thickness direction retardation measured with light with a wavelength of 550nm at 23°C. Rth(λ) can be obtained by formula: Rth(λ)=(nx-nz)×d when the thickness of the layer (film) is d(nm). (4) Nz coefficient The Nz coefficient can be obtained by Nz=Rth/Re. (5) Angle When referring to an angle in this specification, the angle includes both a clockwise direction and a counterclockwise direction with respect to the reference direction. Therefore, for example, "45°" means ±45°.

A. Polarizing plate A-1. The overall composition of the polarizer Fig. 1 is a schematic cross-sectional view of a polarizing plate according to an embodiment of the present invention. The polarizer 10 has a protective layer 12, a polarizer 11, an iodine permeation suppression layer 40 and an adhesive layer 30 in this order. Another protective layer (not shown) can also be provided on the side of the polarizer 11 opposite to the protective layer 12 according to the purpose. The adhesive layer 30 is arranged as the outermost layer, and the polarizing plate can be attached to the image display device (essentially the image display unit). The polarizing plate can be used as a viewing side polarizing plate in an image display device, and can also be used as a back side polarizing plate.

In the embodiment of the present invention, an iodine permeation suppression layer 40 is provided between the polarizer 11 and the adhesive layer 30 as described above. The iodine permeation suppression layer represents a cured product or a thermally cured product of a coating film of an organic solvent solution of the upper resin. In addition, the glass transition temperature (Tg) of the resin constituting the iodine permeation suppression layer is, for example, 85° C. or more, and the weight average molecular weight Mw is, for example, 25,000 or more. By arranging the iodine permeation suppression layer at a predetermined position of the polarizing plate, the iodine in the polarizing element can be significantly inhibited from moving to the adhesive layer under the high temperature and high humidity environment (the final image display device is essentially the image display unit) . As a result, a thin polarizer (details will be described later) can achieve excellent durability in a high temperature and high humidity environment. Moreover, when the polarizing plate is applied to the image display device, the corrosion of the metal components (such as electrodes, sensors, wiring, and metal layer) of the image display device can be significantly suppressed, and reflections under high temperature and high humidity environments can be suppressed The rate has risen. This effect is unique to thin polarizers. That is, the inventors of the present invention found that the movement of iodine, which is one of the factors that cause changes in the optical properties of a thin polarizer under a high-temperature and high-humidity environment (representatively, the degree of polarization), is useful as a means to prevent the movement of the iodine. The method is to set the above-mentioned iodine permeation suppression layer (cured layer or thermosetting layer of the coating film of the organic solvent solution of the resin with specific Tg and Mw) so that the iodine existence index of the adhesive layer (to be described later) is Below 0.050, the present invention was completed. In addition, as described later, the iodine permeation suppressing layer can be formed very thin, and the protective layer on the side opposite to the viewing side can be omitted by providing the iodine permeation suppressing layer, so the additive effect can also be achieved. Contribute to the further thinning of the polarizer.

In a polarizer with a retardation layer, two or more iodine permeation suppression layers can also be provided between the polarizer and the adhesive layer (for example, FIGS. 5 and 6). Since the polarizer with retardation layer has two or more iodine transmission suppression layers, when the polarizer with retardation layer is applied to an image display device, corrosion of metal components can be significantly suppressed.

In the polarizing plate with retardation layer shown in FIG. 4, two iodine permeation suppression layers are provided between the polarizer and the adhesive layer. In the example shown in FIG. 5, the iodine permeation suppression layer is provided with two layers between the polarizer 11 and the retardation layer 20 and between the retardation layer 20 and the adhesive layer 30. In one embodiment, the iodine permeation suppression layer is provided adjacent to the polarizer. In another embodiment, the iodine permeation suppression layer is provided adjacent to the retardation layer. In this manual, "adjacent" means to directly laminate without passing through an adhesive layer or the like.

In the polarizing plate with retardation layer shown in FIG. 6, three iodine permeation suppression layers are provided between the polarizer and the adhesive layer. In the example shown in FIG. 6, the iodine permeation suppression layer is provided with two layers between the polarizer 11 and the retardation layer 20, and one layer is provided between the retardation layer 20 and the adhesive layer 30. One of the two iodine penetration suppression layers between the polarizer 11 and the retardation layer 20 is arranged to be adjacent to the polarizer, and the other is arranged to be adjacent to the retardation layer.

In the polarizing plate with retardation layer, the iodine transmission suppression layer may be 4 or more layers (for example, 4 layers, 5 layers, and 6 layers). The greater the amount of iodine permeation inhibition layer, the more effective the metal corrosion inhibition can be improved. The number of iodine permeation suppression layers can be set in consideration of cost, manufacturing efficiency, and the total thickness of the polarizer with retardation layer.

In the embodiment of the present invention, the iodine presence index of the adhesive layer 30 as described above is 0.050 or less. The iodine presence index is preferably 0.040 or less, more preferably 0.030 or less, more preferably 0.020 or less, and particularly preferably 0.015 or less. The smaller the iodine presence index, the better, and ideally it is zero, and the lower limit thereof may be, for example, 0.001. The iodine presence index is an indicator of the amount of iodine that moves from the polarizer to the adhesive layer under a high temperature and high humidity environment. The smaller the index, the smaller the movement of iodine is blocked by the iodine permeation suppression layer, and the smaller the change in the amount of iodine in the polarizer is. . Therefore, as long as the iodine existence index is within the above range, the migration of iodine can be suppressed, and the thin polarizing plate (details will be described later) can achieve excellent durability in a high temperature and high humidity environment. The Iodine Presence Index is based on the secondary ion mass analysis (TOF) of the polarizing plate after the reliability test (placed in an environment of 85°C and 85%RH for 240 hours, and then placed in an environment of 23°C and 55%RH for 24 hours) -SIMS). More specifically, the presence of iodine index TOF-SIMS can be measured on the surface of the adhesive layer after the reliability test, pick derived from acrylic acid C (adhesive) of ₃ H ₃ O ₂ resulting from the negative secondary ions ^- ( m / z = 71) and from the ionic strength of iodine ^{I - (m / z = 127} ) of the ionic strength, and was calculated by the following formula. Iodine presence index=I ^- ionic strength/C ₃ H ₃ O ₂ ^- ionic strength In addition, the adhesive layer 30 can have a structure known in the industry, so the detailed structure of the adhesive layer is omitted.

The polarizing plate of the embodiment of the present invention may be a single sheet or a long strip. The term "long strip" in this specification means an elongated shape having a sufficiently long length with respect to the width, and includes, for example, an elongated shape having a length of 10 times or more with respect to the width, and preferably an elongated shape having a length of 20 times or more. The long strip polarizer can be rolled into a roll.

The total thickness of the polarizing plate should be 45 µm or less, more preferably 40 µm or less, more preferably 35 µm or less, and particularly preferably 30 µm or less. The lower limit of the total thickness may be 22 μm, for example. According to the embodiment of the present invention, an extremely thin polarizing plate as described above can be realized, and the extremely thin polarizing plate can realize excellent durability in a high temperature and high humidity environment. In addition, the polarizing plate can have extremely excellent flexibility and bending durability. Therefore, the polarizer is particularly suitable for use in curved image display devices and/or bendable or foldable image display devices. In addition, the total thickness of the polarizing plate refers to the total thickness of the polarizer, the protective layer, the iodine permeation suppression layer, and the adhesive layer or adhesive layer used to laminate them (that is, the total thickness of the polarizing plate does not include the adhesive The thickness of the layer 30 and the release film that can be temporarily adhered to its surface).

In practical applications, a release film should be temporarily attached to the surface of the adhesive layer 30 before the polarizing plate is used. By temporarily adhering the release film, the roll of polarizing plate can be formed while protecting the adhesive layer.

A-2. Polarizing parts The representative of the polarizer is composed of polyvinyl alcohol (PVA) resin film containing dichroic material. The thickness of the polarizer is preferably 1µm~8µm, preferably 1µm~7µm, and more preferably 2µm~5µm. As long as the thickness of the polarizer is within the above range, it can greatly contribute to the thinning of the polarizer. Moreover, in the thin polarizing plate using the polarizer, the effect of the present invention is very significant.

The boric acid content of the polarizer is preferably 10% by weight or more, preferably 13% to 25% by weight. As long as the boric acid content of the polarizer is within the above range, it is possible to maintain the ease of adjusting the curling during bonding by the additive effect of the iodine content described later, suppress curling during heating, and improve the appearance during heating. Durability. The boric acid content can be calculated as the amount of boric acid per unit weight of the polarizer by the neutralization method using the following formula. [Math 1]

The iodine content of the polarizer is preferably 2% by weight or more, preferably 2% to 10% by weight. As long as the iodine content of the polarizer is within the above range, the additive effect of the above-mentioned boric acid content can maintain the ease of adjusting the curling during bonding, suppress curling during heating, and improve the appearance during heating. Durability. The "iodine content" in this specification means the total amount of iodine contained in the polarizer (PVA-based resin film). More specifically, the iodine iodide ion (I ^-) is present in the form of a polarizer and the like, and the iodine content of the present specification is meant that molecular iodine (I _2), polyiodide ions _{^{(I 3 - -, I 5}} ) Contains all these forms of iodine. The iodine content can be calculated by, for example, the calibration curve method of X-ray fluorescence analysis. In addition, polyiodide ions exist in a state where PVA-iodide complexes are formed in the polarizer. By forming the complex compound, it is possible to exhibit absorption dichroism in the wavelength range of visible light. Specifically, the complexes (PVA · I ₃ ^-) PVA and tri-iodide ions having a light absorption peak around 470nm, and PVA complexes with five iodide ions (PVA · I ₅ ^-) having in the vicinity of 600nm Absorption peak. As a result, polyiodide ions can absorb light in a wide range of visible light according to their form. On the other hand, an iodide ion (I ^-) having a light absorption peak around 230nm, which is associated with substantially no absorption of visible light. Therefore, the polyiodide ions present in the state of the complex with PVA are mainly related to the absorption performance of the polarizer.

The polarizer should exhibit absorption dichroism at any wavelength from 380nm to 780nm. The monomer transmittance Ts of the polarizer is preferably 40%~48%, more preferably 41%~46%. The degree of polarization P of the polarizer is preferably 97.0% or more, preferably 99.0% or more, and more preferably 99.9% or more. The above monomer transmittance represents the Y value obtained by measuring and calibrating the visual sensitivity using an ultraviolet-visible spectrophotometer. The above-mentioned degree of polarization is representatively calculated based on the parallel transmittance Tp and the orthogonal transmittance Tc obtained by measuring with an ultraviolet-visible light spectrophotometer and performing visual sensitivity correction, using the following equations. Polarization (%)={(Tp-Tc)/(Tp+Tc)} ^1/2 ×100

The polarizer can be made by using a laminate of more than two layers. Specific examples of the polarizer obtained by using the laminate include a polarizer obtained by using a laminate of a resin substrate and a PVA-based resin layer formed on the resin substrate by coating. The polarizer obtained by using a laminate of a resin substrate and a PVA-based resin layer formed on the resin substrate can be produced, for example, by applying a PVA-based resin solution to the resin substrate and drying it, A PVA-based resin layer is formed on the resin substrate to obtain a laminate of the resin substrate and the PVA-based resin layer; and the laminate is extended and dyed to make the PVA-based resin layer into a polarizer. Stretching typically includes immersing the laminate in a boric acid aqueous solution and stretching. Furthermore, if necessary, stretching may further include stretching the laminated body in the air at a high temperature (for example, 95°C or higher) before stretching in a boric acid aqueous solution. The obtained resin substrate/polarizer laminate can be used directly (that is, the resin substrate can be used as a protective layer for the polarizer), or the resin substrate can be peeled from the resin substrate/polarizer laminate and placed on the peeling surface Depending on the purpose, build up any appropriate protective layer and use it later. The details of the manufacturing method of the polarizer are described in, for example, Japanese Patent Laid-Open No. 2012-73580 and Japanese Patent No. 6470455. In this manual, the entire record of these bulletins is used as a reference.

The manufacturing method of the polarizer typically includes the following steps: forming a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin on one side of the elongated thermoplastic resin substrate to form a laminate; and, for the above The layered body is sequentially subjected to air-assisted stretching treatment, dyeing treatment, underwater stretching treatment and drying shrinkage treatment. The drying shrinkage treatment is to transport the above-mentioned layered body in the longitudinal direction while heating, thereby shrinking it by 2% in the width direction. above. Thereby, it is possible to provide a very thin polarizer with excellent optical characteristics and suppressed jitter in optical characteristics. That is, by introducing auxiliary extension, the crystallinity of PVA can be improved even when PVA is coated on a thermoplastic resin, and high optical properties can be achieved. In addition, at the same time, the orientation of PVA can be improved in advance to prevent problems such as degradation or dissolution of the orientation of PVA when immersed in water in the subsequent dyeing step or stretching step, and high optical properties can be achieved. In addition, when the PVA-based resin layer is immersed in a liquid, compared to the case where the PVA-based resin layer does not contain halide, it is possible to suppress the orientation disorder of the polyvinyl alcohol molecules and the decrease in orientation. Thereby, it is possible to improve the optical characteristics of the polarizer obtained by the treatment step of immersing the laminate in a liquid through dyeing treatment and underwater stretching treatment. In addition, the layered body is shrunk in the width direction through the drying shrinkage treatment, and the optical characteristics can be improved.

A-3. Protective layer The protective layer 12 is formed of any suitable film that can be used as a protective layer of the polarizer. Specific examples of the material that becomes the main component of the film include cellulose resins such as cellulose triacetate (TAC), polyesters, polyvinyl alcohols, polycarbonates, polyamides, and polyamides. Transparent resins such as imine-based, polyether-based, poly-based, polystyrene, polynorbornene, polyolefin, (meth)acrylic, and acetate-based transparent resins, etc. In addition, thermosetting resins such as (meth)acrylic, urethane, (meth)acrylate urethane, epoxy, and silicone resins, or ultraviolet curable resins, etc. may also be mentioned. Other examples include glassy polymers such as silicone polymers. In addition, the polymer film described in Japanese Patent Laid-Open No. 2001-343529 (WO01/37007) can also be used. As the material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted iminium group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain can be used, for example, Examples include resin compositions having alternating copolymers composed of isobutylene and N-methylmaleimide and acrylonitrile-styrene copolymers. The polymer film may be, for example, an extruded product of the above-mentioned resin composition.

In one embodiment, the polarizing plate is arranged on the viewing side of the image display device, and the protective layer 12 is typically arranged on the viewing side thereof. In this case, the protective layer 12 may also be subjected to surface treatments such as hard coating treatment, anti-reflection treatment, anti-adhesion treatment, and anti-glare treatment as needed. And/or, the protective layer 12 can also be processed as needed to improve the visibility through polarized sunglasses (representatively, imparting (elliptical) circular polarization function and imparting ultra-high phase difference). By performing the above processing, even when the display screen is visualized through a polarized lens such as polarized sunglasses, excellent visibility can still be achieved. Therefore, the polarizing plate can also be suitably used in image display devices that can be used outdoors.

The thickness of the protective layer should be 10µm~50µm, more preferably 10µm~30µm. In addition, when the surface treatment is applied, the thickness of the outer protective layer includes the thickness of the surface treatment layer.

A-4. Iodine permeation suppression layer The iodine permeation suppression layer is a cured product or a thermal cured product of the coating film of the organic solvent solution of the resin as described above. As long as the structure is as described above, the thickness can be made very thin (for example, 10 μm or less). The thickness of the iodine permeation suppression layer should be 0.05µm~10µm, more preferably 0.08µm~5µm, more preferably 0.1µm~1µm, especially 0.2µm~0.7µm. In addition, as long as it has the above configuration, the iodine permeation suppression layer can be directly formed on the polarizing member (that is, not permeating through the adhesive layer or the adhesive layer). According to the embodiment of the present invention, as described above, the polarizer and the iodine transmission inhibiting layer are very thin, and the adhesive layer or adhesive used to laminate the iodine transmission inhibiting layer can be omitted, so the total thickness of the polarizing plate can be extremely thin. In addition, since the hygroscopicity and moisture permeability of the iodine permeation suppression layer are smaller than the cured product of an aqueous coating film such as an aqueous solution or a water dispersion, it has the advantage of excellent humidification durability. As a result, it is possible to realize a polarizing plate with excellent durability that can maintain optical characteristics even in a high-temperature and high-humidity environment. Moreover, this iodine permeation suppression layer can suppress the adverse effects of ultraviolet radiation on the polarizing plate (polarizer), for example, compared to a cured product of an ultraviolet curable resin. The iodine permeation inhibiting layer is preferably a cured product of a coating film of a resin organic solvent solution. Compared with the cured product, the cured product has smaller shrinkage during film forming and does not contain residual monomers. Therefore, the deterioration of the film itself can be suppressed and the residual monomers can be prevented from adversely affecting the polarizing plate (polarizer).

In addition, the glass transition temperature (Tg) of the resin constituting the iodine permeation suppression layer is, for example, 85° C. or more, and the weight average molecular weight Mw is, for example, 25,000 or more. As long as the Tg and Mw of the resin are within the above-mentioned ranges, the effect of the iodine permeation inhibiting layer formed by the cured product or thermosetting product of the coating film of the organic solvent solution of the resin is multiplied by the effect of the iodine permeation inhibiting layer. It is thin, and can still significantly inhibit the iodine in the polarizer from moving to the adhesive layer (ultimately the image display unit). As a result, it is possible to realize excellent durability in a high temperature and high humidity environment. The Tg of the resin is preferably above 90°C, more preferably above 100°C, more preferably above 110°C, and particularly preferably above 120°C. The upper limit of Tg may be 200°C, for example. In addition, the Mw of the resin is preferably 30,000 or more, more preferably 35,000 or more, and more preferably 40,000 or more. The upper limit of Mw may be 150,000, for example.

As the resin constituting the iodine permeation suppression layer, any suitable thermoplastic resin or thermosetting resin can be used as long as it can form a cured product or a thermosetting product of a coating film of an organic solvent solution and has the above-mentioned Tg and Mw. Preferably it is a thermoplastic resin. Examples of the thermoplastic resin include acrylic resins and epoxy resins. It can also be used in combination with acrylic resin and epoxy resin. The following describes representative examples of acrylic resins and epoxy resins that can be used to suppress iodine permeation suppression layers.

The acrylic resin typically contains a repeating unit derived from a linear or branched (meth)acrylate monomer as a main component. In this specification, (meth)acrylic acid means acrylic acid and/or methacrylic acid. The acrylic resin may contain repeating units derived from any suitable comonomers for the purpose. Copolymers include, for example, carboxyl group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, aromatic ring-containing (meth)acrylates, and heterocyclic ring-containing vinyl monomers. By appropriately setting the type, number, combination, and copolymerization ratio of monomer units, an acrylic resin having the aforementioned predetermined Mw can be obtained.

(式中，X表示包含反應性基之官能基，且該反應性基係選自於由乙烯基、(甲基)丙烯醯基、苯乙烯基、(甲基)丙烯醯胺基、乙烯基醚基、環氧基、氧雜環丁烷基、羥基、胺基、醛基及羧基所構成群組中之至少1種反應性基，R¹ 及R² 分別獨立表示氫原子、可具有取代基之脂肪族烴基、可具有取代基之芳基或可具有取代基之雜環基，R¹ 及R² 可相互連結形成環)。<Boron-containing acrylic resin> In one embodiment, the acrylic resin includes a copolymer obtained by polymerizing a monomer mixture (hereinafter sometimes referred to as a boron-containing acrylic resin), and the monomer mixture includes More than 50 parts by weight of (meth)acrylic monomers and more than 0 parts by weight and less than 50 parts by weight of monomers represented by formula (1) (hereinafter sometimes referred to as comonomers): [Chemical formula 2]

(In the formula, X represents a functional group containing a reactive group, and the reactive group is selected from the group consisting of vinyl, (meth)acryloyl, styryl, (meth)acrylamido, vinyl At least one reactive group in the group consisting of ether group, epoxy group, oxetanyl group, hydroxyl group, amino group, aldehyde group and carboxyl group, R ¹ and R ² each independently represent a hydrogen atom and may have substitution The aliphatic hydrocarbon group of the group, the aryl group which may have a substituent, or the heterocyclic group which may have a substituent, R ¹ and R ² may be connected to each other to form a ring).

(式中，R⁶ 表示任意官能基，j及k表示1以上之整數)。The boron-containing acrylic resin typically has a repeating unit represented by the following formula. By polymerizing a monomer mixture containing a comonomer represented by formula (1) and a (meth)acrylic monomer, the boron-containing acrylic resin has a boron-containing substituent in the side chain (for example, in the following formula: Repeating unit of k). Thereby, when the iodine permeation suppression layer is arranged adjacent to the polarizer, the adhesion to the polarizer can be improved. The boron-containing substituent may be connected to the boron-containing acrylic resin (that is, in the form of a block) to be contained, or may be contained randomly. [Chemical formula 3]

(In the formula, R ⁶ represents an arbitrary functional group, and j and k represent an integer of 1 or more).

＜(Meth)acrylic monomer＞ As the (meth)acrylic monomer, any appropriate (meth)acrylic monomer can be used. Examples include (meth)acrylate monomers having a linear or branched structure, and (meth)acrylate monomers having a cyclic structure.

Linear or branched (meth)acrylate monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and (meth)acrylic acid. Isopropyl ester, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tertiary butyl (meth)acrylate, methyl 2-ethylhexyl (meth)acrylate, (methyl) 2-hydroxyethyl acrylate and the like. Preferably, methyl (meth)acrylate can be used. The (meth)acrylate-based monomer may be used alone or in combination of two or more kinds.

The (meth)acrylate monomers having a cyclic structure include, for example, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, 1-(meth)acrylate Adamantyl ester, dicyclopentenyl (meth)acrylate, dicyclopentenoxyethyl (meth)acrylate, dicyclopentyl (meth)acrylate, biphenyl (meth)acrylate, ortho-linked Phenoxyethyl (meth)acrylate, o-biphenoxyethoxyethyl (meth)acrylate, m-biphenoxyethyl acrylate, p-biphenoxyethyl (meth)acrylate, o-biphenoxyethyl (meth)acrylate, o-biphenoxyethyl (meth)acrylate Phenoxy-2-hydroxypropyl (meth)acrylate, p-biphenoxy-2-hydroxypropyl (meth)acrylate, m-biphenoxy-2-hydroxypropyl (meth)acrylate , N-(meth)acryloyloxyethyl-o-biphenyl=urethane, N-(meth)acryloyloxyethyl-p-biphenyl=urethane, N-(methyl) Acrylic oxyethyl-m-biphenyl = urethane, o-phenylphenol glycidyl ether acrylate and other biphenyl-containing monomers, triphenyl (meth)acrylate, o-tamoxifen (Meth)acrylate and the like. Preferably, 1-adamantyl (meth)acrylate and dicyclopentyl (meth)acrylate can be used. By using these monomers, a polymer with a high glass transition temperature can be obtained. These monomers may be used by only 1 type or in combination of 2 or more types.

In addition, a silsesquioxane compound having a (meth)acryloyl group may be used in place of the (meth)acrylate-based monomer. By using a silsesquioxane compound, an acrylic polymer with a high glass transition temperature can be obtained. It is known that silsesquioxane compounds have various framework structures such as cage structures, ladder structures, random structures and the like. The silsesquioxane compound may have only one type of these structures, or may have two or more types. The silsesquioxane compound may be used alone or in combination of two or more kinds.

For the silsesquioxane compound containing (meth)acryloyl group, for example, MAC grade and AC grade of Toagosei SQ series can be used. MAC grade is a silsesquioxane compound containing a methacrylic acid group, and specific examples include MAC-SQ TM-100, MAC-SQ SI-20, MAC-SQ HDM and the like. AC grade is a silsesquioxane compound containing an acrylic group, and specific examples include AC-SQ TA-100, AC-SQ SI-20, and the like.

The (meth)acrylic monomer can be used in an amount greater than 50 parts by weight with respect to 100 parts by weight of the monomer mixture.

＜Comonomers＞ As a comonomer, a monomer represented by the above formula (1) can be used. By using the comonomer, a boron-containing substituent can be introduced into the side chain of the obtained polymer. A comonomer may be used by only 1 type or in combination of 2 or more types.

The aliphatic hydrocarbon group of the above formula (1) may include a linear or branched alkyl group having 1 to 20 carbon atoms, a cyclic alkyl group having 3 to 20 carbon atoms, and an alkene having 2 to 20 carbon atoms. base. Examples of the aryl group include a phenyl group having 6 to 20 carbon atoms, which may have a substituent, and a naphthyl group having 10 to 20 carbon atoms, which may have a substituent. Examples of the heterocyclic group include a 5-membered ring group or a 6-membered ring group containing at least one heteroatom which may have a substituent. In addition, R ¹ and R ² may be connected to each other to form a ring. R ¹ and R ^{2 are} preferably a hydrogen atom or a straight or branched chain alkyl group with 1 to 3 carbon atoms, more preferably a hydrogen atom.

The reactive group contained in the functional group represented by X is selected from the group consisting of vinyl, (meth)acrylic acid, styryl, (meth)acrylic amido, vinyl ether, epoxy, oxygen At least one of the group consisting of a heterocyclobutanyl group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group. Preferably, the reactive group is a (meth)acrylic acid group and/or a (meth)acrylic acid amino group. By having these reactive groups, when the iodine permeation suppression layer is arranged adjacent to the polarizer, the adhesion with the polarizer can be improved.

In one embodiment, the functional group represented by X is preferably a functional group represented by Z-Y-. Here, Z represents a functional group containing a reactive group, and the reactive group is selected from the group consisting of vinyl, (meth)acryl, styryl, (meth)acrylamido, vinyl ether At least one reactive group in the group consisting of an epoxy group, an epoxy group, an oxetanyl group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group, and Y represents a phenylene group or an alkylene group.

[化學式5]

Specifically, the following compounds can be used as a comonomer. [Chemical formula 4]

[Chemical formula 5]

The comonomer can be used in a content greater than 0 parts by weight and less than 50 parts by weight relative to 100 parts by weight of the monomer mixture. It is preferably 0.01 parts by weight or more and less than 50 parts by weight, more preferably 0.05 parts by weight to 20 parts by weight, more preferably 0.1 parts by weight to 10 parts by weight, and particularly preferably 0.5 parts by weight to 5 parts by weight.

＜Acrylic resin containing lactone ring etc.＞

In another embodiment, the acrylic resin has a repeating unit including a ring structure selected from the group consisting of lactone ring units, glutaric anhydride units, glutarimide units, maleic anhydride units, and maleic acid units. Amine (N-substituted maleimidine) unit. The repeating unit including the ring structure may be contained in only one type in the repeating unit of the acrylic resin, or two or more types may be contained in it.

The lactone ring unit is preferably represented by the following general formula (2):

通式(2)中，R² 、R³ 及R⁴ 分別獨立表示氫原子或碳數1~20之有機殘基。此外，有機殘基亦可包含有氧原子。丙烯酸系樹脂中可僅包含有單一的內酯環單元，亦可包含有多個上述通式(2)中之R² 、R³ 及R⁴ 互異的內酯環單元。具有內酯環單元之丙烯酸系樹脂已載於例如日本專利特開2008-181078號公報中，而本說明書即援用該公報之記載作為參考。[Chemical formula 6]

In the general formula (2), R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an organic residue with 1 to 20 carbon atoms. In addition, the organic residue may also contain oxygen atoms. The acrylic resin may include only a single lactone ring unit, or may include a plurality of lactone ring units in which R ² , R ³ and R ⁴ in the above general formula (2) are different from each other. The acrylic resin having a lactone ring unit has been described in, for example, Japanese Patent Laid-Open No. 2008-181078, and the description of the publication is used as a reference in this specification.

The glutarimide unit is preferably represented by the following general formula (3):

[Chemical formula 7]

In the general formula (3), R ¹¹ and R ¹² each independently represent hydrogen or an alkyl group with 1 to 8 carbons, and R ¹³ represents an alkyl group with 1 to 18 carbons, a cycloalkyl group with 3 to 12 carbons, or 6 to 10 carbons. Aryl. In the general formula (3), it is desirable that R ¹¹ and R ¹² are each independently hydrogen or methyl, and R ¹³ is hydrogen, methyl, butyl, or cyclohexyl. More preferably, R ¹¹ is methyl, R ¹² is hydrogen, and R ¹³ is methyl. The acrylic resin may include only a single glutarimide unit, or may include a plurality of glutarimide units in which R ¹¹ , R ¹² and R ¹³ in the general formula (3) above are different from each other. Acrylic resins having pentadiimide units are described in, for example, Japanese Patent Laid-Open No. 2006-309033, Japanese Patent Laid-Open No. 2006-317560, Japanese Patent Laid-Open No. 2006-328334, and Japanese Patent Laid-Open No. 2006 -337491, Japanese Patent Laid-Open No. 2006-337492, Japanese Patent Laid-Open No. 2006-337493, and Japanese Patent Laid-Open No. 2006-337569, and this specification refers to the description of the gazette as a reference. In addition, for the glutaric anhydride unit, except that ^{the nitrogen atom substituted by R 13 of the} above general formula (3) is changed to an oxygen atom, the above description of the glutarimide unit applies.

The maleic anhydride unit and the maleimid (N-substituted maleimid) unit can specify the structure by the name, so the specific description is omitted.

The content ratio of the repeating unit containing the ring structure in the acrylic resin is preferably 1 mol%~50 mol%, more preferably 10 mol%~40 mol%, more preferably 20 mol%~30 mol% . In addition, the acrylic resin contains a repeating unit derived from the above-mentioned (meth)acrylic monomer as a main repeating unit.

＜Epoxy resin＞ As the epoxy resin, it is preferable to use an epoxy resin having an aromatic ring. By using an epoxy resin with an aromatic ring as the epoxy resin, the adhesion between the iodine permeation suppression layer and the polarizer can be improved. In addition, when the adhesive layer is arranged adjacent to the iodine permeation suppression layer, the anchoring force of the adhesive layer can be improved. Examples of epoxy resins with aromatic rings include bisphenol-type epoxy resins such as bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, and bisphenol S-type epoxy resin; phenol novolac epoxy resin, cresol Novolac epoxy resin, paraben phenol novolac epoxy resin, etc Multifunctional epoxy resin, naphthol epoxy resin, naphthalene epoxy resin, biphenyl epoxy resin, etc. Preferably, bisphenol A type epoxy resin, biphenyl type epoxy resin, and bisphenol F type epoxy resin can be used. The epoxy resin may be used by only 1 type or in combination of 2 or more types.

The iodine permeation inhibiting layer can be formed by applying an organic solvent solution of the resin as described above to form a coating film, and curing or thermally curing the coating film. As the organic solvent, any appropriate organic solvent that can dissolve or uniformly disperse the acrylic resin can be used. Specific examples of the organic solvent include ethyl acetate, toluene, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclopentanone, and cyclohexanone. The resin concentration of the solution is preferably 3 parts by weight to 20 parts by weight relative to 100 parts by weight of the solvent. As long as the resin concentration is the above, a uniform coating film can be formed.

The solution can be coated on any suitable substrate, and can also be coated on the polarizer. When the solution is applied to the substrate, the cured product (iodine permeation suppression layer) of the coating film formed on the substrate is transferred to the polarizer. When the solution is applied to the polarizer, the protective layer is directly formed on the polarizer by drying (curing) the coating film. Preferably, the solution is coated on the polarizer, and the protective layer is directly formed on the polarizer. As long as it has the above configuration, the adhesive layer or the adhesive layer required for transfer can be omitted, so the polarizing plate can be made thinner. Any appropriate method can be adopted for the coating method of the solution. Specific examples include a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, a die coating method, a curtain coating method, a spray coating method, and a knife coating method (cutting wheel coating method, etc.).

By curing or thermally hardening the coating film of the solution, an iodine permeation suppression layer can be formed. The heating temperature for curing or thermal hardening should be below 100℃, more preferably 50℃~70℃. As long as the heating temperature is within the above range, adverse effects on the polarizer can be prevented. The heating time can be changed according to the heating temperature. The heating time can be, for example, 1 minute to 10 minutes.

The iodine permeation suppression layer (essentially an organic solvent solution of the above resin) may also contain any appropriate additives according to the purpose. Specific examples of additives include ultraviolet absorbers; leveling agents; hindered phenol, phosphorus, sulfur and other antioxidants; stabilizers such as light-resistant stabilizers, weather-resistant stabilizers, and heat stabilizers; reinforcing materials such as glass fiber and carbon fiber; Near-infrared absorber; ginseng (dibromide propyl) phosphate, triallyl phosphate, antimony oxide and other flame retardants; anionic, cationic, non-ionic surfactants and other antistatic agents; inorganic pigments, Organic pigments, dyes and other colorants; organic or inorganic fillers; resin modifiers; organic or inorganic fillers; plasticizers; slip agents; antistatic agents; flame retardants, etc. The type, quantity, combination, addition amount, etc. of the additives can be appropriately set according to the purpose.

The iodine permeation suppression layer is, for example, an iodine absorption index of 0.015 or less. The iodine absorption index is preferably less than 0.012, more preferably less than 0.009, more preferably less than 0.007, and particularly preferably less than 0.005. The smaller the iodine absorption index, the better, and ideally it is zero, and its lower limit may be, for example, 0.001. The iodine absorption index is an indicator of the iodine permeation inhibiting ability of the iodine permeation inhibiting layer. The smaller the index, the more difficult it is for iodine to be absorbed by the iodine permeation inhibiting layer (that is, the iodine is easily blocked by the iodine permeation inhibiting layer). Therefore, as long as the iodine absorption index is within the range, the iodine existence index of the adhesive layer can be set to 0.050 or less as described above, and the iodine in the polarizer can be significantly prevented from moving to the adhesive layer (in the end, the image display device, It is essentially an image display unit). As a result, the thin polarizing plate can achieve excellent durability in a high temperature and high humidity environment. Moreover, even when the polarizing plate is applied to the image display device, the corrosion of the metal components (such as electrodes, sensors, wiring, metal layer) of the image display device can be significantly suppressed, and it can be suppressed in a high temperature and high humidity environment. Reliability is reduced due to iodine, so the increase in reflectivity can be suppressed. In addition, the iodine permeation suppression layer is as described above, and the potassium absorption index is preferably 0.015 or less. The potassium absorption index is preferably less than 0.013, more preferably less than 0.011, and particularly preferably less than 0.009. The lower the potassium absorption index, the better, and it is ideally zero, and its lower limit may be 0.002, for example. Potassium absorption index is an indicator of the potassium permeation inhibition ability of iodine permeation inhibition layer. The smaller the index, the less easily potassium is absorbed by iodine permeation inhibition layer. As a result, potassium iodide form of iodine and potassium polyiodide (I ₃ ^- K ⁺ ) form of iodine are more difficult to absorb. It is not easy to be absorbed by iodine through the suppression layer. Therefore, as long as the potassium absorption index is within the above range, not only the iodine monomer can inhibit the movement of iodine even in the form of potassium iodide and potassium polyiodide. The iodine absorption index can be defined as the iodine intensity (kcps) obtained by X-ray fluorescence analysis of the iodine permeation suppression layer, and the potassium absorption index can be defined as the potassium intensity (kcps) obtained by the X-ray fluorescence analysis of the iodine permeation suppression layer.

B. Polarizing plate with retardation layer B-1. The overall composition of the polarizing plate with retardation layer The polarizing plate with retardation layer of the embodiment of the present invention has a polarizing plate and a retardation layer. The polarizing plate is the one described in item A above. In the embodiment of the present invention, the retardation layer is disposed between the polarizer and the adhesive layer. The retardation layer is an orientation cured layer of a liquid crystal compound having a circular polarization function or an elliptical polarization function (hereinafter, it may be simply referred to as a liquid crystal orientation cured layer). 2A is a schematic cross-sectional view of a polarizing plate with a retardation layer according to an embodiment of the present invention; FIG. 2B is a schematic cross-sectional view of a polarizing plate with a retardation layer according to another embodiment of the present invention. The polarizing plates 100 and 101 with retardation layer of FIGS. 2A and 2B each have a protective layer 12, a polarizer 11, a retardation layer 20, and an adhesive layer 30 in order from the viewing side. In the embodiment of the present invention, the iodine permeation suppression layer 40 is provided between the polarizer 11 and the adhesive layer 30. The iodine transmission suppression layer is provided in the polarizing plate with the retardation layer, as described in the above-mentioned polarizing plate, which can significantly inhibit the iodine in the polarizer from moving to the adhesive layer (the final image display device is essentially the image display unit). ). As a result, a thin polarizer with retardation layer can achieve excellent durability in a high temperature and high humidity environment. Moreover, when the polarizing plate with retardation layer is applied to the image display device, the corrosion of the metal components (such as electrodes, sensors, wiring, metal layer) of the image display device can be significantly suppressed, and it can be suppressed at high temperatures. The reflectivity increases in high humidity environments. The iodine permeation suppression layer 40 may be provided between the polarizer 11 and the retardation layer 20 as shown in FIG. 2A (ie adjacent to the polarizer 11), or may be provided between the retardation layer 20 and the adhesive layer 30 as shown in FIG. 2B between. When the iodine permeation suppression layer is provided between the polarizer and the retardation layer (especially when the iodine permeation suppression layer is adjacent to the polarizer), the iodine can be prevented from moving away from the polarizer in a high temperature and high humidity environment, thereby improving reliability advantage. When the iodine permeation inhibiting layer is placed between the retardation layer and the adhesive layer (especially when the iodine permeation inhibiting layer is adjacent to the adhesive layer), it can also prevent components other than iodine that may affect metal corrosion (such as ultraviolet rays). The residue monomer components in the hardening adhesive and the decomposition products of the photoinitiator) move into the adhesive, which has the advantage of further enhancing the metal corrosion inhibition effect.

As shown in FIG. 3, the polarizing plate 102 with a retardation layer of another embodiment may be provided with another retardation layer 50 and/or a conductive layer or an isotropic substrate 60 with a conductive layer. Another retardation layer 50 may be provided between the retardation 20 and the adhesive layer 30 (that is, the outer side of the retardation layer 20). The other retardation layer represents the upper refractive index characteristic showing the relationship of nz>nx=ny. The conductive layer or the isotropic substrate 60 with a conductive layer may typically be provided between the iodine permeation inhibiting layer 40 and the adhesive layer 30 (that is, the outer side of the iodine permeation inhibiting layer 40). The other retardation layer 50 and the conductive layer or the isotropic substrate 60 with a conductive layer are representatively arranged in order from the retardation layer 20 side. In the example of the drawing, an iodine permeation suppression layer 40, a retardation layer 20, another retardation layer 50, and a conductive layer or an isotropic substrate 60 with a conductive layer are provided in this order from the viewing side, but only The other retardation layer 50 is provided between the retardation 20 and the adhesive layer 30, and the conductive layer or the isotropic substrate 60 with the conductive layer is provided between the iodine permeation suppression layer 40 and the adhesive layer 30. Use any appropriate configuration sequence. The other retardation layer 50 and the conductive layer or the isotropic substrate 60 with a conductive layer represent any layers that can be provided as needed, and either or both of them can be omitted. In addition, for convenience, the retardation layer 20 may be referred to as a first retardation layer, and the other retardation layer 50 may be referred to as a second retardation layer. When a conductive layer or an isotropic substrate with a conductive layer can be provided, the polarizing plate with a retardation layer can be applied to the so-called touch sensor integrated between the image display unit (such as the organic EL unit) and the polarizing plate Internal touch panel type input display device. In the embodiment of the present invention, by disposing the conductive layer or the isotropic substrate 60 with a conductive layer on the outer side of the iodine permeation suppression layer 40, the corrosion of the conductive layer can be significantly suppressed.

As described above, the first retardation layer 20 is a liquid crystal orientation cured layer. The first retardation layer 20 may be a single layer as shown in FIG. 2A, FIG. 2B, and FIG. 3, or may have a laminated structure of the first liquid crystal orientation curing layer 21 and the second liquid crystal orientation curing layer 22 as shown in FIG. 4 .

The above-mentioned embodiments may be combined as appropriate, and obvious changes in the industry may be added to the constituent elements of the above-mentioned embodiments. For example, the second retardation layer 50 and/or the conductive layer or the isotropic substrate 60 with the conductive layer can be provided on the polarizing plate 101 with retardation layer in FIG. 2B; the polarizing plate 101 with retardation layer in FIG. 2B The retardation layer 20 of FIG. 4 may also have a two-layer structure; the second retardation layer 50 and/or a conductive layer or an isotropic base with a conductive layer can be provided on the polarizing plate 103 with a retardation layer in FIG. 4 The iodine transmission suppression layer 40 of the polarizing plate 102 with a retardation layer of FIG. 3 can also be provided between the retardation layer 20 and the conductive layer or the isotropic substrate 60 with a conductive layer.

The polarizing plate with retardation layer of the embodiment of the present invention may further include other retardation layers. The optical properties of other retardation layers (for example, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement position, etc. can be appropriately set according to the purpose.

The total thickness of the polarizer with retardation layer should be less than 60 µm, more preferably less than 55 µm, more preferably less than 50 µm, especially less than 40 µm. The lower limit of the total thickness may be 28 μm, for example. According to the embodiment of the present invention, an extremely thin polarizing plate with a retardation layer can be realized as described above, and the extremely thin polarizing plate with a retardation layer can achieve excellent durability in a high temperature and high humidity environment. Moreover, even when such a very thin polarizer with a retardation layer is applied to an image display device, the metal components (such as electrodes, sensors, wiring, and metal layer) of the image display device can still be significantly suppressed. Corrosion, and can suppress the increase in reflectivity in a high temperature and high humidity environment. In addition, the total thickness of the polarizing plate with retardation layer refers to the polarizing plate, the retardation layer (the first retardation layer and the second retardation layer when the second retardation layer is present), the iodine transmission suppression layer, and The total thickness of the adhesive layer or the adhesive layer used for stacking (that is, the total thickness of the polarizing plate with the retardation layer does not include the conductive layer or the isotropic substrate 60 with the conductive layer, and the adhesive layer 30 and the thickness of the release film that can be temporarily adhered to its surface).

Regarding the composition, effect and use of the polarizing plate, the description of the above item A can also be applied to the polarizing plate with retardation layer, which can be cited as the description of the polarizing plate with retardation layer. For example, the description about the shape (single or long strip) and thinning of the polarizing plate, the image display device to which the polarizing plate can be applied, the release film, and the direct formation of the iodine permeation suppression layer on the polarizer can be cited as the related phase The record of the polarizing plate of the differential layer. These are only examples, and the quoted records are not subject to such restrictions and should be self-explanatory. Similarly, the description about the structure, effect, and use of the polarizing plate with retardation layer can be cited as the description about the polarizing plate in the description that can be used for the polarizing plate.

Hereinafter, the first retardation layer, the second retardation layer, and the conductive layer or the isotropic substrate with the conductive layer, which are the constituent elements of the polarizing plate with a retardation layer, will be described. The polarizer, protective layer, and iodine permeation suppression layer are as described in item A above.

B-2. The first retardation layer The first retardation layer 20 is a liquid crystal orientation cured layer as described above. By using a liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be much larger than that of the non-liquid crystal material. Therefore, the thickness of the retardation layer required to obtain the desired in-plane retardation can be greatly reduced. As a result, the polarizing plate with retardation layer can be further thinned. The "liquid crystal orientation cured layer" in this specification refers to a layer in which the liquid crystal compound is oriented in a predetermined direction in the layer, and the orientation state of the liquid crystal compound has been fixed. In addition, the concept of "directionally hardened layer" includes an directional hardened layer obtained by hardening a liquid crystal monomer as described later. In this embodiment, it represents that the rod-shaped liquid crystal compound is aligned in the direction of the slow axis of the first retardation layer (orientated along the plane).

The liquid crystal compound may be, for example, a liquid crystal compound (nematic liquid crystal) whose liquid crystal phase is a nematic phase. As such a liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal properties of the liquid crystal compound can be expressed by lyotropic or thermotropic. The liquid crystal polymer and the liquid crystal monomer may be used alone or in combination.

When the liquid crystal compound is a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer and a crosslinkable monomer. This is because the alignment state of the liquid crystal monomer can be fixed by polymerizing or crosslinking (ie, hardening) the liquid crystal monomer. After aligning the liquid crystal monomers, for example, by polymerizing or crosslinking the liquid crystal monomers with each other, the above-mentioned alignment state can be fixed by this. Here, a polymer is formed by polymerization, and a three-dimensional network structure is formed by cross-linking, but these are non-liquid crystalline. Therefore, the formed first retardation layer does not change into a liquid crystal phase, a glass phase, or a crystalline phase due to temperature changes that are unique to liquid crystal compounds, for example. As a result, the first retardation layer becomes a retardation layer that is not affected by temperature changes and is extremely stable.

The temperature range in which the liquid crystal monomer exhibits liquid crystallinity will vary depending on its type. Specifically, the temperature range is preferably 40°C to 120°C, more preferably 50°C to 100°C, and most preferably 60°C to 90°C.

Any appropriate liquid crystal monomer can be used as the above-mentioned liquid crystal monomer. For example, the polymerizable mesogen compounds described in Japanese Patent Special Publication 2002-533742 (WO00/37585), EP358208 (US5211877), EP66137 (US4388453), WO93/22397, EP0261712, DE19504224, DE4408171, GB2280445, etc. can be used. Specific examples of the polymerizable mesogen compound include, for example, BASF's trade name LC242, Merck's trade name E7, and Wacker-Chem's trade name LC-Sillicon-CC3767. The liquid crystal monomer is preferably, for example, a nematic liquid crystal monomer.

The liquid crystal orientation curing layer can be formed by the following method: performing orientation treatment on the surface of a predetermined substrate, and coating the surface with a coating liquid containing a liquid crystal compound to orient the liquid crystal compound in the direction corresponding to the orientation treatment, and fix it The orientation state. In one embodiment, the substrate is any suitable resin film, and the liquid crystal orientation cured layer formed on the substrate can be transferred to the surface of an adjacent layer (for example, a polarizer, an iodine transmission suppression layer).

The above-mentioned orientation processing can adopt any appropriate orientation processing. Specific examples include mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment. Specific examples of mechanical orientation treatment include friction treatment and stretching treatment. Specific examples of the physical orientation treatment include magnetic field orientation treatment and electric field orientation treatment. Specific examples of the chemical orientation treatment include oblique vapor deposition and light orientation treatment. The processing conditions of various directional processing can adopt any appropriate conditions according to the purpose.

The orientation of the liquid crystal compound can be processed at a temperature that can exhibit a liquid crystal phase according to the type of the liquid crystal compound. By performing the temperature treatment, the liquid crystal compound becomes a liquid crystal state, and the liquid crystal compound is oriented according to the orientation treatment direction of the substrate surface.

In one embodiment, the fixation of the orientation state is performed by cooling the liquid crystal compound that has been oriented in the above-mentioned manner. When the liquid crystal compound is a polymerizable monomer or a crosslinkable monomer, the fixation of the alignment state is performed by subjecting the liquid crystal compound aligned in the above-mentioned manner to a polymerization treatment or a crosslinking treatment.

Specific examples of the liquid crystal compound and the details of the method for forming the oriented solidified layer are described in Japanese Patent Laid-Open No. 2006-163343. In this manual, the record in the bulletin is used as a reference.

In one embodiment, the first retardation layer 20 is a single layer as shown in FIGS. 2A, 2B, and 3. When the first retardation layer 20 is composed of a single layer, its thickness is preferably 0.5 μm-7 μm, and preferably 1 μm-5 μm. By using the liquid crystal compound, it is possible to achieve the same in-plane phase difference as the resin film with a much thinner thickness than the resin film.

The first retardation layer has a circular polarization function or an elliptical polarization function as described above. The first retardation layer represents the upper refractive index characteristic exhibiting a relationship of nx>ny=nz. The first retardation layer is typically provided to impart anti-reflection properties to the polarizing plate, and when the first retardation layer is a single layer, it can function as a λ/4 plate. At this time, the in-plane retardation Re (550) of the first retardation layer is preferably 100 nm to 190 nm, more 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 exactly the same, but also the case where they are substantially the same. Therefore, there may be situations of ny>nz or ny<nz within a range that does not impair the effect of the present invention.

The Nz coefficient of the first retardation layer is preferably 0.9 to 1.5, more preferably 0.9 to 1.3. By satisfying the above relationship, when the obtained polarizing plate with retardation layer is used in an image display device, a very excellent reflection hue can be achieved.

The first retardation layer can exhibit inverse dispersion wavelength characteristics in which the retardation value increases with the wavelength of the measurement light, and can exhibit the normal wavelength dispersion characteristics with the retardation value becoming smaller with the wavelength of the measurement light, and it can also exhibit the retardation value that hardly varies. Measure the flat wavelength dispersion characteristics of light wavelength changes. In one embodiment, the first retardation layer exhibits reverse dispersion wavelength characteristics. At this time, the Re(450)/Re(550) of the retardation layer is preferably 0.8 or more and less than 1, more preferably 0.8 or more and 0.95 or less. As long as the structure is as described above, very excellent anti-reflection characteristics can be achieved.

The angle θ formed by the slow axis of the first retardation layer 20 and the absorption axis of the polarizer 11 is preferably 40°-50°, more preferably 42°-48°, and more preferably about 45°. As long as the angle θ is within the above range, by making the first retardation layer into a λ/4 plate as described above, it is possible to obtain a phase-attached phase with very excellent circular polarization characteristics (and as a result, very excellent anti-reflection characteristics) Polarizing plate with differential layer.

In another embodiment, as shown in FIG. 4, the first retardation layer 20 has a layered structure of a first liquid crystal orientation cured layer 21 and a second liquid crystal orientation cured layer 22. At this time, any one of the first liquid crystal orientation curing layer 21 and the second liquid crystal orientation curing layer 22 can function as a λ/4 plate, and the other can function as a λ/2 plate. Therefore, the thicknesses of the first liquid crystal orientation curing layer 21 and the second liquid crystal orientation curing layer 22 can be adjusted in order to obtain a desired in-plane phase difference of the λ/4 plate or the λ/2 plate. For example, when the first liquid crystal orientation curing layer 21 functions as a λ/2 plate and the second liquid crystal orientation curing layer 22 functions as a λ/4 plate, the thickness of the first liquid crystal orientation curing layer 21 is, for example, 2.0 μm to 3.0 μm. The thickness of the second liquid crystal orientation curing layer 22 is, for example, 1.0 μm to 2.0 μm. At this time, the in-plane phase difference Re(550) of the first liquid crystal orientation curing layer is preferably 200nm~300nm, more preferably 230nm~290nm, and more preferably 250nm~280nm. The in-plane phase difference Re (550) of the second liquid crystal orientation cured layer is the same as that described above for the single layer. The angle formed by the slow axis of the first liquid crystal orientation curing layer and the absorption axis of the polarizer is preferably 10°-20°, more preferably 12°-18°, and more preferably about 15°. The angle formed by the slow axis of the second liquid crystal orientation curing layer and the absorption axis of the polarizer is preferably 70°~80°, more preferably 72°~78°, and more preferably about 75°. With the above configuration, characteristics close to ideal inverse wavelength dispersion characteristics can be obtained, and as a result, very excellent anti-reflection characteristics can be achieved. Regarding the liquid crystal compounds constituting the first and second liquid crystal alignment cured layers, the method of forming the first and second liquid crystal alignment cured layers, and the optical characteristics are as described above with respect to the single layer.

B-3. Second retardation layer As described above, the second retardation layer may be a so-called positive C-plate that exhibits the relationship of nz>nx=ny in refractive index characteristics. By using the positive C plate as the second retardation layer, oblique reflection can be prevented well, and the anti-reflection function can be made to widen the viewing angle. At this time, the thickness direction retardation Rth(550) of the second retardation layer is preferably -50nm~-300nm, more preferably -70nm~-250nm, more preferably -90nm~-200nm, particularly preferably -100nm~ -180nm. Here, "nx=ny" includes not only the case where nx and ny are strictly equal, but also the 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 can be formed of any appropriate material. The second retardation layer is preferably composed of a film containing a liquid crystal material fixed in a homeotropic orientation. The liquid crystal material (liquid crystal compound) that can align the vertical plane 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 compounds described in paragraphs [0020] to [0028] in Japanese Patent Laid-Open No. 2002-333642 and the method for forming the retardation layer. At this time, the thickness of the second retardation layer is preferably 0.5μm~10μm, more preferably 0.5μm~8μm, and more preferably 0.5μm~5μm.

B-4. Conductive layer or isotropic substrate with conductive layer The conductive layer can be formed by forming a metal oxide film on any appropriate substrate by any appropriate film forming method (for example, vacuum evaporation, sputtering, CVD, ion plating, spraying, 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 can be made by transferring the above-mentioned substrate to the first retardation layer (or the second retardation layer when the iodine permeation suppression layer or the second retardation layer is present), and the conductive layer alone is used as the second retardation layer. The constituent layer of the polarizing plate can also be laminated on the first retardation layer in the form of a laminate of a conductive layer and a substrate (a substrate with a conductive layer) (or an iodine permeation suppression layer or a second retardation layer) It is the second retardation layer). It is more desirable that the above-mentioned substrate is optically isotropic, so the conductive layer can be used as an isotropic substrate with a conductive layer for a polarizing plate with a retardation layer.

Any suitable isotropic substrate can be used as an optically isotropic substrate (isotropic substrate). The material constituting the isotropic substrate may include, for example, a material having a resin that does not have a conjugated system such as norbornene-based resin or olefin-based resin as the main skeleton, and a material having a lactone ring or glutaric acid in the main chain of the acrylic resin Materials with cyclic structures such as imine rings. If the material is used, the phase difference that occurs with the orientation of the molecular chain when the isotropic substrate is formed can be suppressed to be small. The thickness of the isotropic substrate is preferably 50 µm or less, 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 the conductive layer may be patterned as needed. The conductive part and the insulating part can be formed by patterning. As a result, electrodes can be formed. The electrode can function as a touch sensing electrode for sensing contact with the touch panel. Any appropriate method can be adopted for the patterning method. Specific examples of the patterning method include a wet etching method and a screen printing method.

C. Image display device The polarizing plate described in the above item A and the polarizing plate with a retardation layer described in the above item B can be applied to an image display device. Therefore, the embodiment of the present invention includes an image display device using the polarizing plate or the polarizing plate with retardation layer. Representative examples of image display devices include liquid crystal display devices and electroluminescence (EL) display devices (for example, organic EL display devices and inorganic EL display devices). The image display device of the embodiment of the present invention is representatively provided with the polarizing plate described in the above item A or the polarizing plate with the retardation layer described in the above item B on the viewing side. The polarizing plate with retardation layer is laminated so that the retardation layer becomes the image display unit (for example, liquid crystal cell, organic EL cell, inorganic EL cell) side (the polarizer becomes the viewing side). Although the image display device is very thin, the corrosion of metal components is significantly suppressed. In one embodiment, the image display device has a curved shape (essentially a curved display screen), and/or bendable or foldable. In addition, the polarizing plate described in the above item A can also be arranged on the back side of the image display device according to the purpose.

Example Hereinafter, the present invention will be specifically described with examples, but the present invention is not limited by these examples. The measuring methods of each characteristic are as follows. In addition, as long as there is no special note, the "parts" and "%" in the examples and comparative examples are the basis of weight.

(1) Thickness The thickness of 10 μm or less was measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name "MCPD-3000"). The thickness greater than 10 μm is measured using a digital micrometer (manufactured by Anritsu, product name "KC-351C").

(2) Iodine presence index The polarizing plate with retardation layer or the polarizing plate obtained in the examples and comparative examples was bonded to the alkali-free glass to prepare a test sample. After putting the test sample in the reliability test (placed in an environment of 85℃・85%RH for 240 hours, and then placed in an environment of 23℃・55%RH for 24 hours), use a dressing knife to remove the entire alkali-free glass Peel off the adhesive. The surface of the adhesive of the peeled test sample was subjected to secondary ion mass analysis (TOF-SIMS) measurement using "TOFSIMS5" manufactured by IONTOF. The measurement conditions are as follows.・Primary ion irradiated: Bi ₃ ²⁺・Primary ion acceleration voltage: 25kV ・Measurement area: 100µm ² _{・Measurement polarity: C 3} H ₃ derived from acrylic acid (adhesive) is extracted from the negative secondary ions obtained ^{_{O 2 - (m / z =}} 71) and the ionic strength of I from iodine ^- (m / z = 127) of the ionic strength, the presence of iodine index was calculated by the following formula. Iodine presence index = I ^- ionic strength / C ₃ H ₃ O ₂ ^- ionic strength

(3) Iodine absorption index and potassium absorption index The resin solutions used in the Examples and Comparative Examples were coated on a 38-µm polyethylene terephthalate (PET) film so that the thickness after drying became 1 µm and dried to obtain a test sample of the resin layer/PET film . The obtained test sample was immersed in a potassium iodide 10% aqueous solution (90 parts by weight of pure water, 10 parts by weight of potassium iodide) adjusted to 23°C for 24 hours. After immersion, the test sample was taken out from the aqueous solution, and after wiping the water droplets on the surface, the surface of the resin layer was subjected to X-ray fluorescence measurement to obtain the intensity of iodine and potassium (kcps). The intensity of the obtained iodine was used as the iodine absorption index, and the intensity of potassium was used as the potassium absorption index. In addition, the conditions of X-ray fluorescence analysis are as follows. ・Analysis device: X-ray fluorescence analyzer (XRF) manufactured by Rigaku Denki Kogyo, product name "ZSX100e" ・Test specimen: round specimen with a diameter of 10mm ・For cathode: Rhodium ・Spectroscopic crystal: Lithium fluoride ・Exciting light energy: 40kV-90mA ・Iodine measurement line: I-LA ・Quantitative method: FP method ・2θ angle peak: 103.078deg (iodine), 136.847deg (potassium) ・Measurement time: 40 seconds

(4) Polarization changes The polarizing plate with retardation layer or the polarizing plate obtained in the examples and comparative examples was bonded to the alkali-free glass to prepare a test sample. Measure the degree of polarization of the test sample by conventional methods, and use it as the initial degree of polarization. And after the test sample is placed in the reliability test (at 85℃・85%RH environment for 240 hours, then at 23℃・55% RH environment for 24 hours), measure the degree of polarization in the same way as above . Calculate the polarization change according to the following formula. Polarization change (%) = initial polarization (%)-polarization after reliability test (%) And evaluate according to the following benchmarks. Good: Polarization change is less than 5.0% Poor: Polarization change is more than 5.0%

(5) Increased reflectivity The polarizing plates with retardation layer obtained in the examples and comparative examples were bonded to alkali-free glass to prepare test samples. Place the test sample on a reflector with a reflectance of 80%, and use a spectrophotometer (CM700D manufactured by Konica Minolta) in the SCI mode to measure the value at 550 nm as the reflectance (%). As the initial reflectivity. After putting the test sample in the reliability test (place it in an environment of 60℃・90%RH for 500 hours, then put it in an environment of 23℃・55% RH for 24 hours), then measure the reflectance in the same way as above . The increase in reflectance is calculated by the following formula. Increase in reflectivity (%) = initial reflectivity (%)-reflectivity after reliability test (%) And evaluate according to the following benchmarks. Good: The reflectivity rise is less than 0.50% Allowable: The reflectivity rises above 0.50% and less than 1.00% Poor: The reflectivity rises above 1.00%

(6) Metal corrosivity (48 hours) Coat the silver nanowire liquid (manufactured by MERCK company, nanowire size: diameter 115nm, length 20µm~50µm, solid content 0.5% isopropyl alcohol (IPA) solution) with a wire rod so that the wet film thickness becomes 15µm Spread it on one side of a 50µm polyethylene terephthalate (PET) film and dry it in an oven at 100°C for 5 minutes to form a silver nanowire coating. Next, 99 parts of methyl isobutyl ketone (MIBK), 1 part of neopentylerythritol tetraacrylate (PETA), and a photopolymerization initiator (manufactured by BASF Co., Ltd., The product name "IRGACURE 907") 0.03 parts of covering protection solution (solid content concentration: about 1%) is applied to the surface of the silver nanowire coating film and dried in an oven at 100°C for 5 minutes. Next, active energy rays were irradiated to harden the cover protective coating film to produce a metal thin film having a structure of PET film/silver nanowire layer/cover protective layer (thickness 100 nm). Use an adhesive (15 µm) to bond the metal film to a glass plate with a thickness of 0.5 mm to obtain a laminate of metal film/adhesive/glass plate. The resistance value of the obtained laminate was measured with a non-contact resistance measuring device (manufactured by Napson, product name "EC-80"), and it was 50Ω/□.

The polarizing plate with retardation layer or the polarizing plate obtained in the Examples and Comparative Examples was bonded to the surface of the covering protective layer of the metal thin film of the laminate to prepare a test sample. Measure the resistance value of the test sample with a non-contact resistance tester as the initial resistance value. Put the test sample in the reliability test (place it in an environment of 85°C and 85% RH for 48 hours, and then place it in an environment of 23°C and 55% RH for 2 hours), and then measure the resistance value in the same way as above . Calculate the rate of increase in resistance value according to the following formula. In addition, when the measured value (resistance value) is greater than the measurement limit (1000Ω/□) of the non-contact resistance tester, the measured value is assumed to be 1500Ω/□. Rising rate of resistance value (%)={(resistance value after reliability test-initial resistance value)/initial resistance value}×100 And evaluate according to the following benchmarks. Good: The resistance value rise rate is less than 200% Poor: The rate of increase in resistance value is more than 200%

(7) Metal corrosivity (200 hours) The polarizing plates with retardation layer obtained in the Examples and Comparative Examples were bonded to the protective layer forming surface of the metal thin film of the laminate obtained in (2) to prepare test samples. Use a non-contact resistance tester to measure the resistance value of the test sample as the initial resistance value. Put the test sample in the reliability test (place it in an environment of 85°C and 85% RH for 200 hours, and then place it in an environment of 23°C and 55% RH for 2 hours), and then measure the resistance value in the same way as above . Calculate the rate of increase in resistance value according to the following formula. In addition, when the measured value (resistance value) is greater than the measurement limit (1000Ω/□) of the non-contact resistance tester, the measured value is assumed to be 1500Ω/□. Rising rate of resistance value (%)={(resistance value after reliability test-initial resistance value)/initial resistance value}×100 And evaluate according to the following benchmarks. Excellent: The resistance value rise rate is less than 200% Good: the resistance value increase rate is more than 200% and less than 2000% Poor: The rate of increase in resistance value is more than 2000%

[Example 1] 1. Make polarized parts The thermoplastic resin substrate is an amorphous isophthalic acid copolymer polyethylene terephthalate film (thickness: 100µm) with a water absorption rate of 0.75% and a Tg of about 75°C. And applied corona treatment to one side of the resin substrate. In a 9:1 mixture of polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetyl acetyl modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER Z410"). 13 parts by weight of potassium iodide was added to 100 parts by weight of resin, and the resultant was dissolved in water to prepare a PVA aqueous solution (coating liquid). The above-mentioned PVA aqueous solution was applied to the corona-treated surface of the resin substrate and dried at 60° C., thereby forming a PVA-based resin layer with a thickness of 13 μm, thereby producing a laminate. The obtained laminate was uniaxially stretched 2.4 times in the longitudinal direction (long side direction) between rollers with different peripheral speeds in an oven at 130°C (air-assisted stretching treatment). Next, the layered body was immersed in an insoluble bath (a boric acid aqueous solution obtained by mixing 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 (insoluble treatment). Next, while adjusting the concentration of a dye bath (an iodine aqueous solution obtained by mixing iodine and potassium iodide at a weight ratio of 1:7 with respect to 100 parts by weight of water) at a liquid temperature of 30°C, it was immersed in it for 60 seconds to The monomer transmittance (Ts) of the finally obtained polarizer is 43.0% or more (dyeing treatment). Next, it was immersed in a cross-linking bath (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water with a liquid temperature of 40°C) for 30 seconds (cross-linking treatment) ). Then, the layered body was immersed in a boric acid aqueous solution (4.0% by weight of boric acid concentration and 5% by weight of potassium iodide) at a liquid temperature of 70°C, while uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds. Make the total extension ratio up to 5.5 times (underwater extension treatment). After that, the layered body was immersed in a washing bath (an aqueous solution obtained by mixing 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). After that, while drying in an oven maintained at 90°C, the contact surface temperature was maintained at 75°C with a heating roller made of SUS for about 2 seconds (drying shrinkage treatment). The shrinkage rate of the laminate in the width direction obtained by the drying shrinkage treatment was 5.2%. A polarizer with a thickness of 5 µm is formed on the resin substrate in the above manner.

2. Making polarizing plates An HC-COP film was attached as a protective layer to the surface of the polarizer obtained above (the surface on the side opposite to the resin substrate) through an ultraviolet curable adhesive. Specifically, it is applied so that the total thickness of the hardening type adhesive becomes 1.0 μm, and is bonded using a rolling mill. After that, UV rays are irradiated from the protective layer side to harden the adhesive. In addition, the HC-COP film is a cyclic olefin (COP) film (manufactured by ZEON, Japan, product name "ZF12", thickness 25µm) with a hard coat (HC) layer (thickness 2µm) formed on it, and the COP film is used as a polarizer Fit it on the side of the piece. Next, the resin substrate is peeled off to obtain a polarizing plate having a composition of protective layer (HC layer/COP film)/adhesive layer/polarizer.

使用擦拭布擦拭聚對苯二甲酸乙二酯(PET)薄膜(厚度38μm)表面，施行定向處理。定向處理之方向係設為貼合至偏光板時由視辨側觀看時相對於偏光件之吸收軸方向呈15°方向。利用棒塗機將上述液晶塗敷液塗敷至該定向處理表面，並於90℃下進行2分鐘加熱乾燥，藉此使液晶化合物定向。使用金屬鹵素燈以1mJ/cm² 的光照射依上述方式形成的液晶層，使該液晶層硬化，藉此於PET薄膜上形成液晶定向固化層A。液晶定向固化層A的厚度為2.5μm，面內相位差Re(550)為270nm。並且，液晶定向固化層A具有nx＞ny=nz之折射率分布。 變更塗敷厚度，並將定向處理方向設為由視辨側觀看時相對於偏光件之吸收軸方向呈75°方向，除此之外依與上述相同方式於PET薄膜上形成液晶定向固化層B。液晶定向固化層B的厚度為1.5μm，面內相位差Re(550)為140nm。並且，液晶定向固化層B具有nx＞ny=nz之折射率分布。3. Production of the first oriented cured layer and the second oriented cured layer constituting the retardation layer will show a nematic liquid crystal phase polymerizable liquid crystal (made by BASF Corporation: trade name "Paliocolor LC242", represented by the following formula) 10g and 3 g of a photopolymerization initiator (manufactured by BASF Corporation: trade name "IRGACURE 907") of this polymerizable liquid crystal compound was dissolved in 40 g of toluene to prepare a liquid crystal composition (coating liquid). [Chemical formula 8]

Wipe the surface of a polyethylene terephthalate (PET) film (thickness 38 μm) with a wiping cloth, and perform orientation treatment. The direction of the orientation treatment is set to be 15° with respect to the absorption axis direction of the polarizer when viewed from the viewing side when attached to the polarizer. The above-mentioned liquid crystal coating liquid was applied to the alignment treatment surface using a bar coater, and heated and dried at 90° C. for 2 minutes, thereby aligning the liquid crystal compound. A metal halide lamp was used to ^{irradiate the liquid crystal layer formed in the above manner with light of 1 mJ/cm 2} to harden the liquid crystal layer, thereby forming the liquid crystal orientation cured layer A on the PET film. The thickness of the liquid crystal orientation cured layer A was 2.5 μm, and the in-plane phase difference Re (550) was 270 nm. In addition, the liquid crystal orientation curing layer A has a refractive index distribution of nx>ny=nz. Change the coating thickness and set the orientation treatment direction to be 75° with respect to the absorption axis direction of the polarizer when viewed from the viewing side, except that the liquid crystal orientation cured layer B is formed on the PET film in the same manner as above . The thickness of the liquid crystal orientation cured layer B was 1.5 μm, and the in-plane phase difference Re (550) was 140 nm. In addition, the liquid crystal orientation curing layer B has a refractive index distribution of nx>ny=nz.

4. Formation of retardation layer The liquid crystal orientation cured layer A and the liquid crystal orientation cured layer B obtained in 3. above are sequentially transferred onto the surface of the polarizing member of the polarizing plate obtained in the above 2. At this time, the rotation is performed such that the angle formed by the absorption axis of the polarizer and the slow axis of the liquid crystal orientation curing layer A becomes 15°, and the angle formed by the absorption axis of the polarizer and the slow axis of the liquid crystal orientation curing layer B becomes 75°. Printing (fitting). In addition, the respective transfer (bonding) was performed through the ultraviolet curable adhesive (thickness 1.0 μm) used in 2. above. According to the above method, a protective layer (HC layer/COP film)/adhesive layer/polarizer/adhesive layer/phase difference layer (first liquid crystal oriented curing layer/adhesive layer/second liquid crystal oriented curing layer) is produced The layered body composed of.

5. Making polarizing plate with retardation layer 20 parts of acrylic resin (manufactured by Kusumoto Chemical Co., Ltd., product name "B-811", Tg: 110°C, Mw: 40,000) was dissolved in 80 parts of methyl ethyl ketone to obtain a resin solution (20%). The resin solution was coated on the surface of the second liquid crystal orientation cured layer of the laminate obtained in the above 4. with a wire bar, and the coating film was dried at 60°C for 5 minutes to form a coating film of the organic solvent solution of the resin Iodine permeation suppression layer (thickness 0.5µm) formed in the form of a cured product. Next, an adhesive layer (thickness 15 µm) is placed on the surface of the iodine permeation suppression layer to obtain a protective layer (HC layer/COP film)/adhesive layer/polarizer/adhesive layer/phase difference layer (first liquid crystal orientation curing Layer/Adhesive layer/Second liquid crystal orientation curing layer)/Iodine permeation inhibiting layer/Adhesive layer of polarizing plate with retardation layer. The total thickness of the obtained polarizing plate with retardation layer was 39.5 μm. The obtained polarizing plate with retardation layer was used for the evaluation of (4) to (7) above. In addition, the metal corrosivity was compared with Comparative Example 1 (described later) in which an iodine permeation suppression layer was not formed. The results are listed in Table 1.

[Example 2] 97.0 parts of methyl methacrylate (MMA, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., trade name "methyl methacrylate monomer"), 3.0 parts of the comonomer represented by the general formula (1e), and polymerization initiator ( Produced by Fuji Film Wako Pure Chemical Industries, Ltd., brand name "2,2´-Azobis(isobutyronitrile)") 0.2 part was dissolved in 200 parts of toluene. Next, the polymerization reaction was carried out for 5.5 hours while heating to 70° C. in a nitrogen atmosphere to obtain a boron-containing acrylic resin solution (solid content concentration: 33%). The obtained boron-containing acrylic polymer had a Tg of 110°C and a Mw of 80,000. The boron-containing acrylic polymer was used instead of the acrylic resin "B-811", and the thickness of the iodine permeation suppression layer was set to 0.3 µm, except that the retardation layer was produced in the same manner as in Example 1. The polarizing plate. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Example 3] Except that the thickness of the iodine permeation suppression layer was set to 0.5 µm, a polarizing plate with a retardation layer was manufactured in the same manner as in Example 2. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Example 4] Except that thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) 1256B40", Tg: 100°C, Mw: 45000) is used instead of the acrylic resin "B-811", the same as in Example 1 In the same way, a polarizing plate with retardation layer is produced. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Example 5] Use thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) YX7200B35", Tg: 150°C, Mw: 30000) instead of acrylic resin "B-811" and pass iodine through the suppression layer The thickness was set to 0.3 µm, except that the polarizing plate with retardation layer was manufactured in the same manner as in Example 1. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Example 6] Except that the thickness of the iodine permeation suppression layer was set to 0.5 µm, a polarizing plate with a retardation layer was produced in the same manner as in Example 5. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Example 7] Except that 15 parts of "B-811" and 85 parts of thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) YX6954BH30") (in terms of solid content) are used instead of acrylic resin "B Except for -811", the polarizing plate with retardation layer was manufactured in the same manner as in Example 1. The Tg of this blend is 125°C and the Mw is 38,000. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Example 8] Apply the resin blend used in Example 7 to the polarizer side of the polarizing plate obtained with a protective layer (HC layer/COP film)/adhesive layer/polarizer composition in Example 1 to 2. , And form an iodine permeation suppression layer (thickness 0.5μm) composed of a cured product of a coating film of a resin organic solvent solution. The liquid crystal orientation curing layer A and the liquid crystal orientation curing layer B were sequentially transferred to the surface of the iodine permeation suppression layer in the same manner as in Example 1, to obtain a protective layer (HC layer/COP film)/adhesive layer/polarizer/iodine Polarizing plate with retardation layer composed of suppression layer/adhesive layer/retardation layer (first liquid crystal oriented curing layer/adhesive layer/second liquid crystal oriented curing layer)/adhesive layer. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Example 9] Except for using the boron-containing acrylic polymer in Example 2, in the same manner as in Example 8, a protective layer (HC layer/COP film)/adhesive layer/polarizer/iodine permeation inhibiting layer was prepared. Layered body. Next, a blend of 15 parts of boron-containing acrylic polymer in Example 2 and 85 parts of thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., trade name "jER (registered trademark) YX6954BH30") (in terms of solid content) was used Other than that, in the same manner as in Example 1, a protective layer (HC layer/COP film)/adhesive layer/polarizer/iodine transmission suppression layer/adhesive layer/phase difference layer (first liquid crystal orientation curing Layer/Adhesive layer/Second liquid crystal orientation curing layer)/Iodine permeation inhibiting layer/Adhesive layer of polarizing plate with retardation layer. The total thickness of the obtained polarizing plate with retardation layer was 40 μm. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 2.

[Example 10] The iodine permeation suppressing layer provided between the polarizing member and the retardation layer and adjacent to the polarizing member used 15 parts of the boron-containing acrylic polymer obtained in Example 2 and a thermoplastic epoxy resin (manufactured by Mitsubishi Chemical Co., commercial product). Named "jER (registered trademark) YX6954BH30") a blend of 85 parts (in terms of solid content), except that the polarizing plate with retardation layer was obtained in the same manner as in Example 9. The total thickness of the obtained polarizing plate with retardation layer was 40 μm. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 2.

[Example 11] The iodine permeation suppression layer formed between the polarizer and the retardation layer and adjacent to the polarizer is formed between the polarizer and the retardation layer and adjacent to the retardation layer, except that it is the same as in Example 10 Method to obtain a protective layer (HC layer/COP film)/adhesive layer/polarizer/adhesive layer/iodine transmission suppression layer/phase difference layer (first liquid crystal oriented curing layer/adhesive layer/second liquid crystal oriented curing Layer)/Iodine permeation suppression layer/Adhesive layer composed of polarizing plate with retardation layer. The total thickness of the obtained polarizing plate with retardation layer was 40 μm. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 2.

[Example 12] In the same manner as in Example 9, an iodine transmission suppression layer was further formed between the polarizing member and the retardation layer and adjacent to the polarizing member. Other than that, in the same manner as in Example 11, a protective layer (HC layer/ COP film)/adhesive layer/polarizer/iodine transmission suppression layer/adhesive layer/iodine transmission suppression layer/phase difference layer (first liquid crystal oriented cured layer/adhesive layer/second liquid crystal oriented cured layer)/iodine transmission Polarizing plate with retardation layer composed of suppression layer/adhesive layer. The total thickness of the obtained polarizing plate with retardation layer was 40.5 μm. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 2.

[Comparative Example 1] Except that the iodine permeation suppression layer was not formed, a polarizing plate with a retardation layer was produced in the same manner as in Example 1. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Comparative Example 2] Acrylic resin "B-723" (manufactured by Kusumoto Chemical Co., Ltd., Tg: 54°C, Mw: 200,000) was used instead of acrylic resin "B-811", except that the additional phase was produced in the same manner as in Example 1. Polarizing plate with differential layer. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Comparative Example 3] A photocurable epoxy resin (manufactured by Mitsubishi Chemical Co., brand name "jER (registered trademark) 828" is used instead of the acrylic resin "B-811", and "CPI100P" manufactured by San-Apro Ltd. is used as a photopolymerization initiator. ), except that the polarizing plate with retardation layer was manufactured in the same manner as in Example 1. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Comparative Example 4] Except that PVA resin (manufactured by Mitsubishi Chemical Co., trade name "GOHSEFIMER Z200", Tg: 80°C, Mw: 8800) was used instead of acrylic resin "B-811", the attachment was produced in the same manner as in Example 1. Polarizing plate of retardation layer. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Reference example 1] 1. Make a polarizing plate In the same manner as in Example 1, a polarizing plate having a protective layer (HC layer/COP film)/polarizer composition was obtained.

2. Production of retardation film that constitutes the retardation layer 2-1. The polymerization of polyester carbonate resin uses a batch polymerization consisting of 2 vertical reactors equipped with a stirring blade and a reflux cooler controlled to 100°C The device is aggregated. Feed in bis[9-(2-phenoxycarbonylethyl)茀-9-yl]methane 29.60 parts by mass (0.046mol), isosorbide (ISB) 29.21 parts by mass (0.200mol), spiroglycerin (SPG) 42.28 parts by mass (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. After replacing the pressure with nitrogen in the reactor, it is heated with a heating medium, and stirring is started when the internal temperature reaches 100°C. The internal temperature was brought to 220°C 40 minutes after the start of the temperature increase, and the pressure was started while maintaining the temperature, so that it became 13.3 kPa 90 minutes after the temperature reached 220°C. The phenol vapor by-produced with the polymerization reaction is introduced into a reflux cooler at 100°C, a small amount of monomer components contained in the phenol vapor are returned to the reactor, and uncondensed phenol vapor is introduced into a condenser at 45°C for recovery. After nitrogen was introduced into the first reactor to temporarily return to atmospheric pressure, the oligomerization reaction solution in the first reactor was transferred to the second reactor. Next, the temperature increase and pressure reduction in the second reactor were started, and the internal temperature was set to 240° C. and the pressure was set to 0.2 kPa over 50 minutes. Thereafter, polymerization is carried out until a predetermined stirring power is reached. At the time point when a predetermined power is reached, nitrogen is introduced into the reactor to restore the pressure, and the produced polyester carbonate-based resin is extruded into water, and the bundle is cut to obtain pellets.

2-2. Making retardation film After drying the obtained polyester carbonate-based resin (pellet) in vacuum at 80°C for 5 hours, use a uniaxial extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250°C) and T-die (width 200mm). , Setting temperature: 250℃), cooling roll (setting temperature: 120~130℃) and film forming device of the coiler to produce a long resin film with a thickness of 135μm. 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 times to obtain a retardation film with a thickness of 53 μm. The Re(550) of the obtained retardation film is 141nm, the Re(450)/Re(550) is 0.82, and the Nz coefficient is 1.12.

3. Making polarizing plate with retardation layer Adhere the retardation film obtained in 2. above on the surface of the polarizer of the polarizing plate obtained in 1. through an acrylic adhesive (thickness 5 μm). At this time, it is bonded so that the absorption axis of the polarizer and the slow axis of the retardation film form an angle of 45°. And set the same adhesive layer as in Example 1 on the surface of the retardation layer. According to the above method, a polarizing plate with a retardation layer having the composition of protective layer/adhesive layer/polarizer/adhesive layer/retardation layer (extended film of resin film)/adhesive layer is obtained. The total thickness of the obtained polarizing plate with retardation layer was 91 μm. The obtained polarizing plate with retardation layer was used for the same evaluation as in Example 1. The results are listed in Table 1 and Table 2.

[Example 13] Except that the retardation layer is not formed, a polarizing plate with a protective layer (HC layer/COP film)/adhesive layer/polarizer/iodine permeation inhibiting layer/adhesive layer is obtained in the same manner as in Example 1. The total thickness of the obtained polarizing plate was 33.5 μm. The obtained polarizing plate was subjected to the same evaluation as in Example 1. The results are listed in Table 1 and Table 2. In addition, this embodiment is a polarizing plate, which is different in composition from a polarizing plate with a retardation layer, so the corrosiveness of the metal is not compared with that of Comparative Example 1.

[Table 1]

[Table 2]

[Evaluate] It is obvious from Table 1 that the polarizing plate with retardation layer and the polarizing plate of the embodiment of the present invention form a predetermined iodine penetration suppression layer to set the iodine existence index of the adhesive layer below a predetermined value, which can be reduced at high temperature and high temperature. The degree of polarization changes in a wet environment, and it has excellent durability. In addition, the polarizing plate with retardation layer and the polarizing plate of the embodiment of the present invention can also significantly suppress the increase in metal corrosion and reflectivity in a high-temperature and high-humidity environment. In addition, it is clear from Reference Example 1 that the aforementioned change in polarization degree, increase in reflectance, and metal corrosion are issues unique to very thin polarizers with retardation layers and polarizers. In addition, comparing Example 1 and Example 13 clearly shows that the presence or absence of the liquid crystal orientation cured layer (very thin retardation layer) has no substantial influence on the effect of the present invention.

It is obvious from Table 2 that the polarizing plates with retardation layer of Examples 9 to 12 of the present invention include two or three layers of iodine permeation suppression layer, even if they are put in for a long time (200 hours) in a high temperature and high humidity environment. It can still significantly inhibit metal corrosion. Therefore, it can be seen that the polarizing plate with retardation layer of Examples 9 to 12 of the present invention can significantly inhibit the corrosion of metal components when applied to an image display device.

Industrial availability The polarizing plate of the present invention can be suitably used in liquid crystal display devices, organic EL display devices, and inorganic EL display devices. The polarizing plate with retardation layer of the present invention can be suitably used as a circular polarizing plate for liquid crystal display devices, organic EL display devices and inorganic EL display devices.

10: Polarizing plate 11: Polarizing parts 12: protective layer 20: Retardation layer (first retardation layer) 21: The first liquid crystal orientation curing layer 22: The second liquid crystal orientation curing layer 30: Adhesive layer 40: Iodine permeation suppression layer 50: Another retardation layer (second retardation layer) 60: Conductive layer or isotropic substrate with conductive layer 100: Polarizing plate with retardation layer 101: Polarizing plate with retardation layer 102: Polarizing plate with retardation layer 103: Polarizing plate with retardation layer 104: Polarizing plate with retardation layer 105: Polarizing plate with retardation layer

Fig. 1 is a schematic cross-sectional view of a polarizing plate according to an embodiment of the present invention. Fig. 2A is a schematic cross-sectional view of a polarizing plate with a retardation layer according to an embodiment of the present invention. Fig. 2B is a schematic cross-sectional view of a polarizing plate with a retardation layer according to another embodiment of the present invention. Fig. 3 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to still another embodiment of the present invention. Fig. 4 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to still another embodiment of the present invention. Fig. 5 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to still another embodiment of the present invention. Fig. 6 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to still another embodiment of the present invention.

10: Polarizing plate

11: Polarizing parts

12: protective layer

30: Adhesive layer

40: Iodine permeation suppression layer

Claims (12)

A polarizing plate has a polarizer, an iodine permeation inhibiting layer and an adhesive layer in sequence, and the iodine existence index of the adhesive layer is less than 0.050. The polarizing plate of claim 1, wherein the iodine permeation suppression layer resin is a cured product or a thermal cured product of a coating film of an organic solvent solution. The polarizing plate of claim 2, wherein the glass transition temperature of the resin constituting the aforementioned iodine permeation inhibiting layer is 85° C. or more, and the weight average molecular weight Mw is 25,000 or more. The polarizing plate of claim 1, wherein the iodine transmission inhibiting layer is provided with two or more layers between the polarizing member and the adhesive layer. The polarizing plate of any one of claims 1 to 4, wherein the thickness of the aforementioned iodine penetration suppression layer is 0.05 μm to 10 μm. The polarizing plate of any one of claims 1 to 5, wherein the resin constituting the iodine permeation inhibiting layer includes a copolymer obtained by polymerizing a monomer mixture, and the monomer mixture includes more than 50 parts by weight of (former) Base) acrylic monomer and more than 0 parts by weight and less than 50 parts by weight of the monomer represented by formula (1): [Chemical formula 1]

(In the formula, X represents a functional group containing a reactive group, and the reactive group is selected from the group consisting of vinyl, (meth)acryloyl, styryl, (meth)acrylamido, vinyl At least one reactive group in the group consisting of ether group, epoxy group, oxetanyl group, hydroxyl group, amino group, aldehyde group and carboxyl group, R ¹ and R ² each independently represent a hydrogen atom and may have substitution The aliphatic hydrocarbon group of the group, the aryl group which may have a substituent, or the heterocyclic group which may have a substituent, R ¹ and R ² may be connected to each other to form a ring). A polarizing plate with a retardation layer, comprising the polarizing plate according to any one of claims 1 to 6 and a retardation layer disposed between the polarizer and the adhesive layer; and The retardation layer is a directional solidified layer of a liquid crystal compound with a circular polarization function or an elliptical polarization function. For example, the polarizing plate with retardation layer of claim 7, wherein the aforementioned retardation layer is a single layer, The Re(550) of the retardation layer is 100nm~190nm, and The angle formed by the slow axis of the retardation layer and the absorption axis of the aforementioned polarizer is 40°-50°. The polarizing plate with retardation layer of claim 7, wherein the retardation layer has a laminated structure of a first liquid crystal compound oriented curing layer and a second liquid crystal compound oriented curing layer; The Re (550) of the orientation curing layer of the first liquid crystal compound is 200nm~300nm, and the angle formed by its slow axis and the absorption axis of the aforementioned polarizer is 10°-20°; The Re (550) of the orientation curing layer of the second liquid crystal compound is 100 nm to 190 nm, and the angle formed by its slow axis and the absorption axis of the polarizer is 70° to 80°. For example, the polarizing plate with retardation layer of any one of claims 7 to 9, the total thickness of which is less than 60 µm. An image display device is provided with a polarizing plate according to any one of claims 1 to 6 or a polarizing plate with a phase difference layer according to any one of claims 7 to 10. Such as the image display device of claim 11, which is an organic electroluminescence display device or an inorganic electroluminescence display device.

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