Polarizing plate and display device

Abstract

The present invention addresses the problem of providing a polarizing plate that is applied to a display element to obtain a display device and does not tend to cause in-plane color unevenness when the display device is viewed from an oblique direction during black display. A polarizing plate according to the present invention comprises a polarizer, a first optically anisotropic layer, and a second optically anisotropic layer in this order. An isotropic layer that exhibits optical isotropy is disposed between the polarizer and the first optically anisotropic layer and / or between the first optically anisotropic layer and the second optically anisotropic layer, at least one surface where the first optically anisotropic layer or the second optically anisotropic layer and the isotropic layer face each other has a specific region in which in-plane birefringence gradually increases along the thickness direction from the surface on the isotropic layer side of the first optically anisotropic layer or the second optically anisotropic layer, and the absolute value of the difference between the refractive index in the in-plane slow axis direction of the surface on the isotropic layer side of the first optically anisotropic layer or the second optically anisotropic layer and the in-plane refractive index of the isotropic layer is 0.04 or less.

Description

Polarizing plate, display device

[0001] The present invention relates to a polarizing plate and a display device.

[0002] BACKGROUND ART Optically anisotropic layers having refractive index anisotropy are used in a variety of applications, such as antireflection films for various display devices such as organic electroluminescence (EL) display devices, and optical compensation films for liquid crystal display devices.

[0003] For example, Patent Document 1 discloses an optical film in which three optically anisotropic layers exhibiting predetermined optical properties are laminated.

[0004] International Publication No. 2022 / 045188

[0005] Recently, there has been a demand for further reduction in in-plane color unevenness when a display is displayed in black and viewed from an oblique direction. The present inventors have studied display devices using the optical film described in the above document and found that there are cases where the display devices cannot meet the standards currently required. The in-plane color unevenness refers to the presence of regions with different colors within the display surface.

[0006] In view of the above circumstances, an object of the present invention is to provide a polarizing plate that can be applied to a display element to obtain a display device, and that is less likely to cause in-plane color unevenness when the display device is set to black display and viewed from an oblique direction. Another object of the present invention is to provide a display device related to the polarizing plate.

[0007] As a result of extensive research into solving the above problems, the present inventors have found that the problems can be solved by the following configuration.

[0008] [1] A polarizing plate having a polarizer, a first optically anisotropic layer, and a second optically anisotropic layer in this order, wherein an isotropic layer A exhibiting optical isotropy is disposed between the first optically anisotropic layer and the second optically anisotropic layer, and the polarizing plate satisfies at least one of Requirement 1 and Requirement 2 described below, or an isotropic layer B exhibiting optical isotropy is disposed between the polarizer and the first optically anisotropic layer, and the polarizing plate satisfies Requirement 3 described below. [2] The polarizing plate according to [1], wherein the thicknesses of the region X, the region Y, and the region Z are 60 to 500 nm. [3] The polarizing plate according to [1] or [2], wherein the in-plane thickness unevenness of the isotropic layer A and the isotropic layer B is 5 to 35 nm. [4] The polarizing plate according to any one of [1] to [3], wherein the first optically anisotropic layer is an A plate. [5] The polarizing plate according to any one of [1] to [4], wherein the first optically anisotropic layer has an in-plane retardation of 150 to 240 nm at a wavelength of 550 nm. [6] The polarizing plate according to any one of [1] to [5], wherein the first optically anisotropic layer contains a discotic liquid crystal compound. [7] The polarizing plate according to any one of [1] to [6], wherein the in-plane refractive indexes of the isotropic layer A and the isotropic layer B are 1.51 to 1.59. [8] The polarizing plate according to any one of [1] to [7], wherein the thicknesses of the isotropic layer A and the isotropic layer B are 0.5 to 20 μm. [9] The polarizing plate according to any one of [1] to [8], wherein the isotropic layer A and the isotropic layer B are pressure-sensitive adhesive layers or ultraviolet-curable adhesive layers.

[10] A display device comprising a display element and the polarizing plate according to any one of [1] to [9].

[0009] According to the present invention, a polarizing plate can be provided that is applied to a display element to obtain a display device, and that is less likely to produce in-plane color unevenness when the display device is set to black display and viewed from an oblique direction. Also, a display device related to the polarizing plate can be provided.

[0010] FIG. 1 is a schematic cross-sectional view of an embodiment of the polarizing plate of the present invention. FIG. 2 is a schematic cross-sectional view of an embodiment showing the configuration of the optically anisotropic layer of the polarizing plate of the present invention. FIG. 3 is a diagram showing the relationship between the absorption axis of the polarizer and the in-plane slow axis of the optically anisotropic layer in the embodiment of the polarizing plate of the present invention shown in FIG. 2. FIG. 4 is a schematic diagram showing the relationship between the absorption axis of the polarizer and the in-plane slow axis of the optically anisotropic layer when observed from the direction of the white arrow in FIG. 2. FIG. 5 is a schematic cross-sectional view of an embodiment showing the configuration of the optically anisotropic layer of the polarizing plate of the present invention. FIG. 6 is a diagram showing the relationship between the absorption axis of the polarizer and the in-plane slow axis of the optically anisotropic layer in the embodiment of the polarizing plate of the present invention shown in FIG. 5. FIG. 7 is a schematic diagram showing the relationship between the absorption axis of the polarizer and the in-plane slow axis of the optically anisotropic layer when observed from the direction of the white arrow in FIG. 5.

[0011] The present invention will be described in detail below. The following description of the components may be based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.

[0012] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits. Furthermore, in this specification, when two or more types of a certain component are present, the "content" of that component means the total content of those two or more components. In this specification, in a numerical range described in stages, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in a numerical range described in this specification, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the Examples. In this specification, a combination of two or more preferred embodiments is a more preferred embodiment.

[0013] In this specification, the bonding direction of a divalent group (for example, -CO-O-) is not limited unless otherwise specified. For example, when Y is -CO-O- in a compound represented by the formula "X-Y-Z," the compound may be "X-O-CO-Z" or "X-CO-O-Z." In this specification, "(meth)acrylic" is a concept that includes both acrylic and methacrylic, "(meth)acryloyl" is a concept that includes both acryloyl and methacryloyl, and "(meth)acrylate" is a concept that includes both acrylate and methacrylate.

[0014] In this specification, the term "solid content" refers to the components that form the optically anisotropic layer, and does not include solvents. The components that form the optically anisotropic layer may be components that undergo a reaction (polymerization) during the formation of the optically anisotropic layer, and their chemical structure may change. Furthermore, as long as the components that form the optically anisotropic layer are in a liquid state, they are considered to be solid content.

[0015] In this specification, unless otherwise specified, the refractive index is the refractive index at a wavelength of 550 nm. In this specification, unless otherwise specified, the slow axis is defined at 550 nm.

[0016] In this specification, unless otherwise specified, Re(λ) and Rth(λ) represent the in-plane retardation and the thickness direction retardation, respectively, at a wavelength λ. Unless otherwise specified, the wavelength λ is 550 nm. In this specification, Re(λ) and Rth(λ) are values ​​measured at a wavelength λ using an AxoScan (manufactured by Axometrics). By inputting the average refractive index ((nx + ny + nz) / 3) and film thickness (d (μm)) into AxoScan, the in-plane slow axis direction (°) Re(λ) = R0(λ) Rth(λ) = ((nx + ny) / 2 - nz) × d is calculated. Note that R0(λ) is displayed as a numerical value calculated by AxoScan, but it means Re(λ).

[0017] Unless otherwise specified, the refractive indices nx, ny, and nz in this specification are measured using an Abbe refractometer (NAR-4T, manufactured by Atago Co., Ltd.) with a sodium lamp (λ = 589 nm) as a light source. Wavelength dependency can be measured using a multi-wavelength Abbe refractometer DR-M2 (manufactured by Atago Co., Ltd.) in combination with an interference filter. Values ​​in the Polymer Handbook (John Wiley & Sons, Inc.) and catalogs for various optical films can also be used. Examples of average refractive index values ​​for major optical films are listed below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).

[0018] In this specification, unless otherwise specified, the weight average molecular weight (Mw) is a polystyrene equivalent value determined by GPC (Gel Permeation Chromatography).

[0019] In this specification, the angular relationship (e.g., "perpendicular," "parallel," etc.) is intended to include the range of error acceptable in the technical field to which the present invention pertains. Specifically, this means that the angle is within a range of less than ±10° from the exact angle, and the error from the exact angle is preferably within a range of ±5° or less, and more preferably within a range of ±3° or less.

[0020] [Polarizing Plate] The polarizing plate of the present invention is described in detail below. The polarizing plate of the present invention has a polarizer, a first optically anisotropic layer, and a second optically anisotropic layer in this order, and an isotropic layer A exhibiting optical isotropy is disposed between the first optically anisotropic layer and the second optically anisotropic layer, and satisfies at least one of Requirement 1 and Requirement 2, or an isotropic layer B exhibiting optical isotropy is disposed between the polarizer and the first optically anisotropic layer, and satisfies Requirement 3. Requirement 1: The first optically anisotropic layer has a region X in which in-plane birefringence gradually increases along the thickness direction from the surface on the isotropic layer A side, and the absolute value of the difference between the refractive index in the in-plane slow axis direction of the surface on the isotropic layer A side of the first optically anisotropic layer and the in-plane refractive index of the isotropic layer A is 0.04 or less. Requirement 2: The second optically anisotropic layer has a region Y in which in-plane birefringence gradually increases from the surface on the isotropic layer A side along the thickness direction, and the absolute value of the difference between the refractive index of the second optically anisotropic layer in the in-plane slow axis direction at the surface on the isotropic layer A side and the in-plane refractive index of isotropic layer A is 0.04 or less. Requirement 3: The first optically anisotropic layer has a region Z in which in-plane birefringence gradually increases from the surface on the isotropic layer B side along the thickness direction, and the absolute value of the difference between the refractive index of the first optically anisotropic layer in the in-plane slow axis direction at the isotropic layer B side and the in-plane refractive index of isotropic layer B is 0.04 or less.

[0021] While the reason why a polarizing plate having the above configuration can solve the problems of the present invention is not entirely clear, the inventors speculate as follows. The following speculation does not limit the mechanism by which the effect is achieved. In other words, mechanisms other than those described below are also within the scope of the present invention. When there is a large difference in refractive index between components constituting a polarizing plate, for example, between an optically anisotropic layer and an isotropic layer, light may be reflected at the interface between the layers, resulting in in-plane color unevenness due to interference of the reflected light. A polarizing plate of the present invention has at least one region in which in-plane birefringence gradually increases along the thickness direction from the surface of the optically anisotropic layer facing the adjacent isotropic layer, and the difference between the refractive index in the in-plane slow axis direction of the surface of the optically anisotropic layer facing the isotropic layer and the in-plane refractive index of the isotropic layer is equal to or less than a predetermined value. This suppresses abrupt changes in refractive index between the optically anisotropic layer and the isotropic layer, and thus reduces reflections. It is speculated that the reduction in interfaces at which light reflects results in reduced in-plane color unevenness.

[0022] The polarizing plate of the present invention will be described below with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view of one embodiment of the polarizing plate of the present invention. The polarizing plate 100 shown in Fig. 1 includes a polarizer 30, an isotropic layer B 50, a first optically anisotropic layer 10, an isotropic layer A 40, and a second optically anisotropic layer 20, in this order.

[0023] The polarizing plate 100 shown in FIG. 1 includes both an isotropic layer A40 and an isotropic layer B50 and satisfies all of the above-described requirements 1 to 3. As shown in FIG. 1 , in the first optically anisotropic layer 10, on the surface facing the isotropic layer A40, there is a region X12 in which in-plane birefringence gradually increases from the surface facing the isotropic layer A40 along the thickness direction (the direction from the first optically anisotropic layer 10 to the polarizer 30). As shown in FIG. 1 , in the first optically anisotropic layer 10, on the surface facing the isotropic layer B50, there is a region Z14 in which in-plane birefringence gradually increases from the surface facing the isotropic layer B50 along the thickness direction (the direction from the first optically anisotropic layer 10 to the second optically anisotropic layer 20). As shown in FIG. 1 , the first optically anisotropic layer 10 preferably has a region 16 (uniform region 1) in which in-plane birefringence does not gradually increase along the thickness direction, which is different from the above-described regions X12 and Z14. As shown in Fig. 1 , the second optically anisotropic layer 20 has a region Y22 on the surface facing the isotropic layer A40, where the in-plane birefringence gradually increases from the surface facing the isotropic layer A40 along the thickness direction (the direction from the first optically anisotropic layer 10 to the second optically anisotropic layer 20). Furthermore, as shown in Fig. 1 , the second optically anisotropic layer 20 preferably has a region 24 (uniform region 2) where the in-plane birefringence does not gradually increase along the thickness direction, as a region different from the region Y22. While Fig. 1 discloses an embodiment having an isotropic layer A40 and an isotropic layer B50, the present invention is not limited to this embodiment, and the polarizing plate of the present invention may have only an isotropic layer A or only an isotropic layer B. For example, when the polarizing plate of the present invention has isotropic layer A but not isotropic layer B, the first optically anisotropic layer may have at least one of region X and region Y, and when the polarizing plate of the present invention has only isotropic layer B but not isotropic layer A, the second optically anisotropic layer may have region Z. When the polarizing plate of the present invention has both isotropic layer A and isotropic layer B, it may have at least one of regions X to Z. The polarizing plate 100 shown in FIG. 1 may have an optional member not shown, and for example, may have an additional optically anisotropic layer on the side of the second optically anisotropic layer 20 opposite to the side of isotropic layer A 40.

[0024] Below, we will explain region X, region Y, and region Z, as well as the characteristic inter-layer relationships of the present invention, and then explain the details of each layer. Note that hereinafter, the concept including region X, region Y, and region Z will also be referred to as a "specific region."

[0025] [Region X, Region Y, and Region Z] Region X, Region Y, and Region Z (specific regions) are regions in which the in-plane birefringence Δn gradually increases along the thickness direction from the surface on the adjacent isotropic layer side. In the specific regions, the in-plane birefringence may increase continuously or stepwise.

[0026] As described above, region X is a region that can be included in the first optically anisotropic layer. Region X is a region disposed on the isotropic layer A side of the first optically anisotropic layer, and is a region in which in-plane birefringence gradually increases from the surface on the isotropic layer A side along the thickness direction (the direction from the first optically anisotropic layer to the polarizer). The increase in in-plane birefringence in region X is greater than 0.00, preferably 0.01 or more, and more preferably 0.03 or more. The increase depends on the intrinsic birefringence of the liquid crystal molecules, but is often 0.05 or less. The increase in in-plane birefringence in region X is the difference between the minimum and maximum values ​​of in-plane birefringence at each position in the thickness direction of region X, and corresponds to the difference between the in-plane birefringence at the surface on the isotropic layer A side of region X and the in-plane birefringence at the position of region X farthest from the isotropic layer A. In this specification, in-plane birefringence refers to the refractive index n in the in-plane slow axis direction. ｅ and the refractive index n in the in-plane fast axis direction, which is the direction perpendicular to the in-plane slow axis direction. ｏand the difference between the refractive index of the liquid crystal compound in the direction of twisting in the thickness direction. For example, when the optically anisotropic layer is a chiral nematic layer (described later), the interfacial reflection with the isotropic layer is maximized in the direction of the alignment axis of the liquid crystal compound at the interface in contact with the isotropic layer. Therefore, when the optically anisotropic layer is a chiral nematic layer, the alignment axis of the liquid crystal compound at the interface with the isotropic layer is read as the in-plane slow axis direction at the surface. Furthermore, the direction perpendicular to the above-mentioned in-plane slow axis direction is read as the in-plane fast axis direction. That is, for example, the absolute value of the difference between the refractive index in the direction of the in-plane slow axis at the surface of the chiral nematic layer and the in-plane refractive index of the isotropic layer is the absolute value of the difference between the refractive index in the direction of the alignment axis of the liquid crystal compound at the interface where the chiral nematic layer is in contact with the isotropic layer and the in-plane refractive index of the isotropic layer. In addition, when the optically anisotropic layer is a chiral nematic layer, the in-plane birefringence at each position in the thickness direction is the difference between the refractive index in the direction of the alignment axis of the liquid crystal compound at each position in the thickness direction and the refractive index in the direction perpendicular to the alignment axis.The increase width of the in-plane birefringence in a specific region is the difference between the minimum and maximum values ​​of the in-plane birefringence at each position in the thickness direction calculated by the above-mentioned replacement, and the alignment axis direction when showing the minimum value and the alignment axis direction when showing the maximum value may be the same or different.In this specification, the surface when referring to the in-plane birefringence and in-plane refractive index of the surface of a certain layer means the region from the interface of the layer to a depth of 50 nm.

[0027] When Requirement 1 is satisfied, the refractive index n in the in-plane slow axis direction of the surface of the first optically anisotropic layer on the isotropic layer A side is ｅ１Ａ and the in-plane refractive index n of the isotropic layer A. Ａ The absolute value of the difference between ｅ１Ａ -n Ａ |) is 0.04 or less. The effect of the present invention is more excellent when |n ｅ１Ａ -n Ａ is preferably 0.03 or less, more preferably 0.02 or less. ｅ１Ａ -n Ａ When the requirement 1 is satisfied, the refractive index n о１Ａ and the in-plane refractive index n of the isotropic layer A. ＡThe absolute value of the difference between о１Ａ -n Ａ |) is preferably 0.04 or less, more preferably 0.03 or less, and more preferably 0.02 or less. ｅ１Ａ -n Ａ The lower limit of | is 0.00.

[0028] Region X may correspond to a portion of the first optically anisotropic layer in the thickness direction, or may correspond to the entire first optically anisotropic layer. When region X corresponds to a portion of the first optically anisotropic layer in the thickness direction, the first optically anisotropic layer has a region different from region X. For example, the first optically anisotropic layer may further have region Z, which will be described later. The first optically anisotropic layer may also have a region (hereinafter also referred to as "uniform region 1") located adjacent to region X and having constant in-plane birefringence in the thickness direction. Furthermore, the first optically anisotropic layer may have region X, uniform region 1 located adjacent to region X, and region Z located adjacent to uniform region 1.

[0029] As described above, region Y is a region that can be included in the second optically anisotropic layer. Region Y is a region disposed on the isotropic layer A side of the second optically anisotropic layer, and is a region in which in-plane birefringence gradually increases from the surface on the isotropic layer A side along the thickness direction (from the polarizer side to the surface opposite the polarizer). The increase in in-plane birefringence in region Y is greater than 0.00, preferably 0.01 or more, and more preferably 0.03 or more. The increase depends on the intrinsic birefringence of the liquid crystal molecules, but is often 0.05 or less. The increase in in-plane birefringence in region Y is the difference between the minimum and maximum values ​​of in-plane birefringence at each position in the thickness direction of region Y, and corresponds to the difference between the in-plane birefringence at the surface on the isotropic layer side of region Y and the in-plane birefringence at the position of region Y farthest from isotropic layer A.

[0030] When requirement 2 is satisfied, the refractive index n in the in-plane slow axis direction of the surface of the second optically anisotropic layer on the isotropic layer A side is ｅ２Ａ and the in-plane refractive index n of the isotropic layer A. Ａ The absolute value of the difference between ｅ２Ａ -n Ａ |) is 0.04 or less. The effect of the present invention is more excellent when |n ｅ２Ａ -nＡ is preferably 0.03 or less, more preferably 0.02 or less. ｅ２Ａ -n Ａ When requirement 2 is satisfied, the refractive index n о２Ａ and the in-plane refractive index n of the isotropic layer A. Ａ The absolute value of the difference between о２Ａ -n Ａ |) is preferably 0.04 or less, more preferably 0.03 or less, and more preferably 0.02 or less. ｅ２Ａ -n Ａ The lower limit of | is 0.00.

[0031] Region Y may correspond to a portion of the second optically anisotropic layer in the thickness direction, or may correspond to the entire second optically anisotropic layer. When region Y corresponds to a portion of the second optically anisotropic layer in the thickness direction, the first optically anisotropic layer has a region different from region Y. For example, the second optically anisotropic layer may have a region adjacent to region Y where the in-plane birefringence is constant in the thickness direction (hereinafter also referred to as "uniform region 2").

[0032] As described above, region Z is a region that can be included in the first optically anisotropic layer. Region Z is a region disposed on the isotropic layer B side of the first optically anisotropic layer, where in-plane birefringence gradually increases from the surface on the isotropic layer B side along the thickness direction (the direction from the polarizer to the first optically anisotropic layer). The increase in in-plane birefringence in region Z is greater than 0.00, preferably 0.01 or more, and more preferably 0.03 or more. The increase depends on the intrinsic birefringence of the liquid crystal molecules, but is often 0.05 or less. The increase in in-plane birefringence in region Z is the difference between the minimum and maximum values ​​of in-plane birefringence at each position in the thickness direction of region Z, and corresponds to the difference between the in-plane birefringence at the surface on the isotropic layer B side of region Z and the in-plane birefringence at the position of region Z farthest from the isotropic layer B.

[0033] When requirement 3 is satisfied, the refractive index n in the in-plane slow axis direction of the surface of the first optically anisotropic layer on the isotropic layer B side is ｅ１Ｂ and the in-plane refractive index n of the isotropic layer B Ｂ The absolute value of the difference between ｅ１Ｂ-n Ｂ |) is 0.04 or less. The effect of the present invention is more excellent when |n ｅ１Ｂ -n Ｂ is preferably 0.03 or less, more preferably 0.02 or less. ｅ１Ｂ -n Ｂ When requirement 3 is satisfied, the refractive index n о１Ｂ and the in-plane refractive index n of the isotropic layer B Ｂ The absolute value of the difference between о１Ｂ -n Ｂ |) is preferably 0.04 or less, more preferably 0.03 or less, and more preferably 0.02 or less. о１Ｂ -n Ｂ The lower limit of | is 0.00.

[0034] Region Z may correspond to a portion of the first optically anisotropic layer in the thickness direction, or may correspond to the entire first optically anisotropic layer. When region Z corresponds to a portion of the first optically anisotropic layer in the thickness direction, the first optically anisotropic layer has a region different from region Z. For example, the first optically anisotropic layer may further have region X described above. The first optically anisotropic layer may also have uniform region 1 located adjacent to region Z. Furthermore, the first optically anisotropic layer may have region Z, uniform region 1 located adjacent to region Z, and region X located adjacent to uniform region 1, as described above.

[0035] The thickness of the specific region is preferably 10 nm or more, more preferably 60 nm or more, more preferably 300 nm or more, and even more preferably 400 nm or more, in order to obtain a more excellent effect of the present invention. The thickness of the specific region is often 1000 nm or less, preferably 750 nm or less, and more preferably 500 nm or less.

[0036] The in-plane birefringence, in-plane refractive index, and thickness of each layer and region are calculated using the following method. Transmission and reflection ellipsometry is performed on the first optically anisotropic layer, the second optically anisotropic layer, and, if present, the isotropic layer A and isotropic layer B, using an ellipsometer in the wavelength range of 500 to 1500 nm. Examples of ellipsometers that can be used include the RC-2 manufactured by Woollam and the SE-2000 manufactured by Semilab. For the measurements, for each azimuthal angle, measurements are performed at a maximum and minimum angle of incidence with a difference of 15° or more in reflection ellipsometry, and measurements are performed at three or more angles with a difference of 30° or more in transmission ellipsometry, including normal incidence. The measurements are performed at two orthogonal angles (vertical and horizontal) on the sample. It is preferable to perform a treatment to reduce the back surface reflection intensity in the reflection ellipsometry. An example of a process for reducing the back surface reflection intensity is sanding the back surface. An optical model is constructed based on the results obtained by the above measurement, assuming the existence of regions X, Y, and Z, and the refractive index and film thickness of each layer are calculated by fitting using the least squares method. A specific fitting procedure is shown below. First, it is assumed that the first optically anisotropic layer and the second optically anisotropic layer have regions X, Y, and Z, as well as uniform regions 1 and 2. The refractive index of each layer is calculated according to the Cauchy model, using n(λ) = A ｎ +B ｎ / λ ２ (A ｎ and B ｎ is a variable, λ is the wavelength, and n(λ) is the refractive index at wavelength λ. ｎ and B ｎ In the first optically anisotropic layer, A is linearly changed in the film thickness direction from the interface side. ｎ and B ｎ coincide with each other, and A ｎ and B ｎ In the second optically anisotropic layer, A ｎ and B ｎIt is assumed that there is no change in the refractive index in the film thickness direction in the uniform region 1 and the uniform region 2. By constructing an optical model according to the above conditions and fitting it to the results obtained using the above-mentioned ellipsometer, the Cauchy model n of the film thickness of each region and the refractive index in the in-plane slow axis direction of each region can be obtained. ｅ (λ) = A ｎｅ +B ｎｅ / λ ２ , and the Cauchy model n of the refractive index in the in-plane fast axis direction о (λ) = A ｎо +B ｎо / λ ２ Calculate the obtained n ｅ (λ) and n о From (λ), the average values ​​of the in-plane birefringence and in-plane refractive index can also be calculated. Note that the refractive index in each direction, the in-plane birefringence, and the in-plane refractive index in each layer and region are values ​​at a wavelength of 550 nm. If the film thickness of a specific region calculated by the above method is 0 nm, the specific region is considered not to exist. The same applies to uniform region 1 and uniform region 2. The in-plane birefringence and in-plane refractive index at the surface of the layer are obtained as the average values ​​in the region up to 20 nm from the interface, obtained by the above method.

[0037] As described above, the polarizing plate of the present invention satisfies requirement 1 or 2 when it has isotropic layer A, and satisfies requirement 3 when it has isotropic layer B. In terms of achieving better effects of the present invention, it is preferable that requirement 1 and requirement 2 are satisfied when it has isotropic layer A.

[0038] Hereinafter, layers that can be included in the polarizing plate of the present invention will be described.

[0039] [Polarizer] The polarizer of the polarizing plate of the present invention may be any component capable of converting natural light into specific linearly polarized light, and may be, for example, an absorptive polarizer. The type of polarizer is not particularly limited, and commonly used polarizers may be used, such as iodine-based polarizers, dye-based polarizers using dichroic dyes, and polyene-based polarizers. Iodine-based polarizers and dye-based polarizers are generally produced by adsorbing iodine or a dichroic dye into polyvinyl alcohol and stretching the resulting mixture. A protective film may be disposed on one or both sides of the polarizer.

[0040] Furthermore, as described in WO 2019 / 131943 and JP 2017-083843 A, a coating-type polarizer may be used that is prepared by coating a liquid crystal compound and a dichroic organic dye (for example, a dichroic azo dye used in the light-absorbing anisotropic film described in WO 2017 / 195833 A) without using polyvinyl alcohol as a binder. That is, the polarizer may be a polarizer formed using a composition containing a polymerizable liquid crystal compound. This coating-type polarizer utilizes the orientation of the liquid crystal compound to orient the dichroic organic dye. As described in JP 2012-083734 A, it is preferable for the polymerizable liquid crystal compound to exhibit smectic properties in order to increase the degree of orientation. Alternatively, as described in WO 2018 / 186503 A, crystallizing the dye is also preferable in order to increase the degree of orientation. WO 2019 / 131943 describes a preferred structure of a polymer liquid crystal for increasing the degree of orientation.

[0041] The polarizing plate may have a polarizer protective film. Examples of the polarizer protective layer include a layer containing a polymer and a layer obtained by polymerizing and curing a polyfunctional monomer. Examples of the polymer include a (meth)acrylic polymer and a cycloolefin polymer. Examples of the polymerizable monomer include a radically polymerizable or cationically polymerizable compound.

[0042] [First Optically Anisotropic Layer] The first optically anisotropic layer of the polarizing plate of the present invention is preferably a layer formed using a composition containing a liquid crystal compound, and more preferably a layer formed by fixing an aligned liquid crystal compound. Hereinafter, the term "fixed" refers to a state in which the alignment of the liquid crystal compound is maintained. Specifically, it is more preferable that the layer has no fluidity and can stably maintain the fixed alignment state without causing changes in the alignment state due to external fields or external forces, usually at temperatures of 0 to 50°C, or under more severe conditions, in the temperature range of -30 to 70°C. The layer formed by fixing an aligned liquid crystal compound may have different degrees of alignment of the liquid crystal compound in some regions (e.g., region X and region Z) of the first optically anisotropic layer.

[0043] The liquid crystal compound may be either a discotic liquid crystal compound or a rod-shaped liquid crystal compound. The discotic liquid crystal compound may be a known compound, such as those described in paragraphs

[0020] to

[0067] of JP-A No. 2007-108732 and paragraphs

[0013] to

[0108] of JP-A No. 2010-244038. The rod-shaped liquid crystal compound may be a known compound, such as those described in claim 1 of JP-A No. 11-513019 and paragraphs

[0026] to

[0098] of JP-A No. 2005-289980.

[0044] The liquid crystal compound may have a polymerizable group, and is preferably a liquid crystal compound having a polymerizable group (polymerizable liquid crystal compound) in that the alignment can be fixed. In this specification, the type of the polymerizable group is not particularly limited, and a functional group capable of undergoing an addition polymerization reaction is preferred, a polymerizable ethylenically unsaturated group or a ring-polymerizable group is more preferred, and a (meth)acryloyl group, a vinyl group, a styryl group, or an allyl group is even more preferred.

[0045] The liquid crystal compound may be a photoisomerizable liquid crystal compound having a site that undergoes photoisomerization. The birefringence of the photoisomerizable liquid crystal compound changes upon photoisomerization. Therefore, by irradiating a layer made of a composition containing the photoisomerizable liquid crystal compound with a specific light to photoisomerize the photoisomerizable liquid crystal compound, the orientation state of the liquid crystal compound in the optically anisotropic layer can be changed, thereby controlling the optical properties of the optically anisotropic layer. Examples of the photoisomerizable liquid crystal compound include the photoisomerizable liquid crystal compounds that can be used in Method 1 described below.

[0046] The type of the first optically anisotropic layer is not particularly limited, but is preferably an A plate in that the effects of the present invention are more excellent. An A plate is one that satisfies either of the following formulas (A1) and (A2), where nx is the refractive index in the in-plane slow axis direction, ny is the refractive index in the direction perpendicular to the in-plane slow axis, and nz is the refractive index in the thickness direction. When formula (A1) is satisfied, it is a so-called positive A plate, and when formula (A2) is satisfied, it is a so-called negative A plate. Formula (A1) nx>ny≒nz Formula (A2) ny<nx≒nz Note that the above "≒" encompasses not only the case where both are completely identical, but also the case where both are substantially identical. The term "substantially the same" means that, for example, "ny ≒ nz" includes cases where (ny - nz) x d is -10 to 10 nm, preferably -5 to 5 nm, and "nx ≒ nz" also includes cases where (nx - nz) x d is -10 to 10 nm, preferably -5 to 5 nm. In (ny - nz) x d, d is the layer thickness.

[0047] In terms of achieving superior effects of the present invention, the first optically anisotropic layer preferably contains a discotic liquid crystal compound, and more preferably is a layer formed by fixing a vertically aligned discotic liquid crystal compound. A layer formed by fixing a vertically aligned discotic liquid crystal compound typically corresponds to a negative A plate. The first optically anisotropic layer may contain a rod-shaped liquid crystal compound, and in this case, is preferably a layer formed by fixing a horizontally aligned rod-shaped liquid crystal compound. A layer formed by fixing a horizontally aligned rod-shaped liquid crystal compound typically corresponds to a positive A plate. The layer formed by fixing a vertically aligned discotic liquid crystal compound and the layer formed by fixing a horizontally aligned rod-shaped liquid crystal compound may each have a region in which the liquid crystal compound is fixed in the above-described alignment state, and the alignment angle may be changed from vertical or horizontal in some regions (e.g., region X and region Z) of the first optically anisotropic layer.

[0048] The first optically anisotropic layer may be composed of one optically anisotropic layer or two or more optically anisotropic layers, and is preferably composed of one optically anisotropic layer in order to enable the optical film to be made thinner.

[0049] The in-plane retardation of the first optically anisotropic layer at a wavelength of 550 nm is preferably 150 nm or more, more preferably 155 nm or more, and even more preferably 160 nm or more, and is preferably 240 nm or less, more preferably 220 nm or less, and even more preferably 200 nm or less, at a wavelength of 550 nm.

[0050] When the polarizing plate has an isotropic layer A, the first optically anisotropic layer preferably has a region X. When the polarizing plate has an isotropic layer B, the first optically anisotropic layer preferably has a region Z. Region X and region Z are as described above. The first optically anisotropic layer also preferably has a uniform region 1. When the first optically anisotropic layer does not have region X or region Z, the entire first optically anisotropic layer corresponds to the uniform region 1. The refractive index n in the in-plane slow axis direction of the uniform region 1 of the first optically anisotropic layer is ｅ１is preferably 1.50 to 1.75, and more preferably 1.55 to 1.65, in terms of more excellent effects of the present invention. １ is preferably 0.30 or less, and more preferably 0.20 or less, in that the effects of the present invention are more excellent. １ is often 0.05 or more, and more often 0.10 or more. The refractive index n in the in-plane slow axis direction of the surface of the first optically anisotropic layer on the second optically anisotropic layer side (isotropic layer A side) is ｅ１Ａ is preferably 1.45 to 1.70, and more preferably 1.50 to 1.65, in terms of more excellent effects of the present invention. １Ａ is preferably 0.04 or less, and more preferably 0.03 or less, in that the effects of the present invention are more excellent. １Ａ The lower limit of the refractive index n in the in-plane slow axis direction of the surface of the first optically anisotropic layer on the polarizer side (the isotropic layer B side) is 0.00. ｅ１Ｂ is preferably 1.45 to 1.70, and more preferably 1.50 to 1.65, in terms of more excellent effects of the present invention. １Ｂ is preferably 1.45 to 1.70, more preferably 1.50 to 1.65, in that the effects of the present invention are more excellent.

[0051] The thickness of the first optically anisotropic layer is preferably 0.5 μm or more, more preferably 1.0 μm or more, and even more preferably 1.3 μm or more. The thickness of the first optically anisotropic layer is preferably 5.0 μm or less, more preferably 3.0 μm or less, and even more preferably 2.5 μm or less. The thickness can be determined, for example, by the above-mentioned method or by measuring the thickness of a cross section of the first optically anisotropic layer at any five or more points using a scanning electron microscope (SEM) and calculating the arithmetic average.

[0052] The angle formed between the in-plane slow axis of the first optically anisotropic layer and the absorption axis of the polarizer is preferably from 40 to 85°, more preferably from 50 to 85°, and even more preferably from 65 to 85°.

[0053] [Second Optically Anisotropic Layer] The second optically anisotropic layer of the polarizing plate of the present invention is preferably a layer formed using a composition containing an aligned liquid crystal compound, and more preferably a layer formed by fixing an aligned liquid crystal compound. Note that the layer formed by fixing an aligned liquid crystal compound only needs to fix the liquid crystal compound in an aligned state, and the degree of alignment of the liquid crystal compound may be different in a partial region (e.g., region Y) of the second optically anisotropic layer. Examples of the liquid crystal compound include the same liquid crystal compounds as those in the first optically anisotropic layer described above.

[0054] The second optically anisotropic layer may be composed of one optically anisotropic layer or two or more optically anisotropic layers. When the second optically anisotropic layer is composed of two or more layers, region Y is located on the surface of the optically anisotropic layer closest to the first optically anisotropic layer (the isotropic layer A side).

[0055] The second optically anisotropic layer is preferably selected from a laminate (hereinafter also referred to as "optically anisotropic layer (AB)") of an optically anisotropic layer comprising fixed rod-shaped liquid crystal compounds twistedly aligned with the thickness direction as the helical axis (hereinafter also referred to as "optically anisotropic layer (A)") and an optically anisotropic layer comprising fixed rod-shaped liquid crystal compounds aligned vertically (hereinafter also referred to as "optically anisotropic layer (B)"), and an optically anisotropic layer comprising fixed discotic liquid crystal compounds aligned vertically (hereinafter also referred to as "optically anisotropic layer (C)"), and is more preferably the optically anisotropic layer (AB). The optically anisotropic layer having fixed rod-shaped liquid crystal compounds that are twistedly aligned with the thickness direction as the helical axis, the optically anisotropic layer having fixed rod-shaped liquid crystal compounds that are vertically aligned, and the optically anisotropic layer having fixed discotic liquid crystal compounds that are vertically aligned may have regions in which the liquid crystal compounds are fixed in the above-mentioned alignment states, and the liquid crystal compounds may be fixed in a state in which the alignment of the liquid crystal compounds is canceled or the alignment angle is changed in some regions (for example, the above-mentioned region Y).

[0056] <Optically anisotropic layer (AB)> The optically anisotropic layer (AB) is an optically anisotropic layer formed by laminating an optically anisotropic layer (A) and an optically anisotropic layer (B), and it is preferable that the optically anisotropic layer (A) and the optically anisotropic layer (B) are laminated in this order from the adhesive layer side.

[0057] (Optically Anisotropic Layer (A)) As described above, the optically anisotropic layer (A) is an optically anisotropic layer formed by fixing rod-shaped liquid crystal compounds that are twisted and aligned with the thickness direction as the helical axis, and is preferably a layer formed by fixing a chiral nematic phase having a so-called helical structure (chiral nematic layer). The optically anisotropic layer (A) is preferably formed using a composition containing a rod-shaped liquid crystal compound that exhibits a nematic liquid crystal layer and a chiral agent described later. The rod-shaped liquid crystal compound is not particularly limited, and examples thereof include rod-shaped liquid crystal compounds that can be contained in the first optically anisotropic layer described above.

[0058] The twist angle of the rod-shaped liquid crystal compound (the twist angle in the alignment axis direction of the liquid crystal compound) is not particularly limited, and is often greater than 0° and less than 360°. From the viewpoint of achieving superior effects of the present invention, the twist angle is preferably 50 to 110°, more preferably 60 to 100°, and even more preferably 70 to 90°. The twist angle is measured using an Axometrics AxoScan (polarimeter) device and the company's instrument analysis software. The twisted alignment of the liquid crystal compound refers to the twisting of the liquid crystal compound from one main surface to the other main surface of the optically anisotropic layer (A) around the thickness direction of the optically anisotropic layer (A). Accordingly, the alignment axis direction (in-plane slow axis direction) of the liquid crystal compound varies depending on the position in the thickness direction of the optically anisotropic layer (A).

[0059] The angle formed between the in-plane slow axis of the first optically anisotropic layer and the in-plane slow axis of the optically anisotropic layer (A) on the surface facing the first optically anisotropic layer is preferably from 0 to 20°, more preferably from 0 to 15°.

[0060] The Re(550) of the optically anisotropic layer (A) is preferably 140 nm or more, more preferably 150 nm or more, and even more preferably 160 nm or more, and is preferably 220 nm or less, more preferably 210 nm or less, and even more preferably 200 nm or less.

[0061] The thickness of the optically anisotropic layer (A) is not particularly limited, but is preferably 0.5 μm or more, more preferably 1.0 μm or more, and even more preferably 1.3 μm or more. The thickness of the optically anisotropic layer (A) is preferably 5.0 μm or less, more preferably 2.5 μm or less, and even more preferably 2.2 μm or less.

[0062] (Optically Anisotropic Layer (B)) As described above, the optically anisotropic layer (B) is a layer formed by fixing vertically aligned rod-shaped liquid crystal compounds. The optically anisotropic layer (B) is preferably formed using a composition containing a rod-shaped liquid crystal compound and a photoalignable polymer described below. The rod-shaped liquid crystal compound is not particularly limited, and examples thereof include the liquid crystal compounds that can be contained in the first optically anisotropic layer described above.

[0063] The Re(550) of the optically anisotropic layer (B) is preferably 0 to 10 nm, more preferably 0 to 5 nm. The Rth(550) of the optically anisotropic layer (B) is preferably −120 nm or more, more preferably −110 nm or more, and even more preferably −100 nm or more. The Rth(550) of the optically anisotropic layer (B) is preferably −20 nm or less, more preferably −30 nm or less, and even more preferably −40 nm or less.

[0064] The thickness of the optically anisotropic layer (B) is not particularly limited, but is preferably 10.0 μm or less, more preferably 5.0 μm or less, and even more preferably 2.0 μm or less. The thickness of the optically anisotropic layer (B) is preferably 0.1 μm or more, and more preferably 0.3 μm or more.

[0065] <Optically Anisotropic Layer (C)> As described above, the optically anisotropic layer (C) is a layer comprising a vertically aligned discotic liquid crystal compound fixed therein. The discotic liquid crystal compound is not particularly limited, and examples thereof include the discotic liquid crystal compounds that can be contained in the first optically anisotropic layer described above.

[0066] The angle between the absorption axis of the polarizer and the in-plane slow axis of the optically anisotropic layer (C) is preferably 0 to 30°, more preferably 5 to 25°, and even more preferably 10 to 20°. The angle between the in-plane slow axis of the first optically anisotropic layer and the in-plane slow axis of the optically anisotropic layer (C) is preferably 30 to 90°, more preferably 40 to 80°, and even more preferably 50 to 70°.

[0067] The Re(550) of the optically anisotropic layer (C) is preferably 100 nm or more, more preferably 105 nm or more, and is preferably 150 nm or less, more preferably 145 nm or less.

[0068] The thickness of the optically anisotropic layer (C) is not particularly limited, but is preferably 10.0 μm or less, more preferably 5.0 μm or less, and even more preferably 2.0 μm or less. The thickness of the optically anisotropic layer (C) is preferably 0.1 μm or more, and more preferably 0.3 μm or more.

[0069] When the polarizing plate has an isotropic layer A, the second optically anisotropic layer preferably has a region Y. The region Y is as described above. The second optically anisotropic layer also preferably has a uniform region 2. When the second optically anisotropic layer does not have a region Y, the entire second optically anisotropic layer corresponds to the uniform region 2. The refractive index n in the in-plane slow axis direction of the uniform region 2 of the second optically anisotropic layer is ｅ２ is preferably 1.50 to 1.75, and more preferably 1.55 to 1.70, in terms of more excellent effects of the present invention. ２ is preferably 0.30 or less, and more preferably 0.20 or less, in that the effects of the present invention are more excellent. ２ is often 0.05 or more, and more often 0.10 or more. The refractive index n in the in-plane slow axis direction of the surface of the second optically anisotropic layer on the first optically anisotropic layer side (isotropic layer A side) is ｅ２Ａ is preferably 1.45 to 1.70, and more preferably 1.50 to 1.65, in terms of more excellent effects of the present invention. ２Ａ is preferably 0.05 or less, and more preferably 0.04 or less, in that the effects of the present invention are more excellent. ２Ａ The lower limit of is 0.00, and is often 0.02 or more.

[0070] The thickness of the second optically anisotropic layer is preferably 0.5 μm or more, more preferably 1.0 μm or more, and even more preferably 1.3 μm or more. The thickness of the second optically anisotropic layer is preferably 5.0 μm or less, more preferably 3.0 μm or less, and even more preferably 2.5 μm or less. The thickness of the second optically anisotropic layer can be measured by the same method as for the first optically anisotropic layer.

[0071] [Isotropic Layer A] The isotropic layer A may be any optically isotropic layer, and is preferably an adhesive layer. The adhesive layer functions to bring adjacent layers (e.g., the first optically anisotropic layer and the second optically anisotropic layer) into close contact with each other, and examples of the adhesive layer include an adhesive layer and a pressure-sensitive adhesive layer.

[0072] The adhesive layer is a layer formed using an adhesive. Examples of adhesives include active energy ray-curable adhesives, aqueous adhesives, solvent-based adhesives, emulsion-based adhesives, solventless adhesives, and thermosetting adhesives, with active energy ray-curable adhesives being preferred. Examples of active energy ray-curable adhesives include electron beam-curable adhesives, ultraviolet ray-curable adhesives, and visible light-curable adhesives, with ultraviolet ray-curable adhesives being preferred. Examples of active energy ray-curable adhesives include known adhesives, with adhesives selected from (meth)acrylate adhesives and epoxy adhesives being preferred. Examples of curable components in (meth)acrylate adhesives include compounds having a (meth)acryloyl group and compounds having a vinyl group. Examples of curable components in epoxy adhesives include compounds having a glycidyl group.

[0073] The method for forming the adhesive layer is not particularly limited, and examples thereof include a method in which an adhesive is applied to at least one layer selected from the first optically anisotropic layer and the second optically anisotropic layer, the first optically anisotropic layer and the second optically anisotropic layer are laminated together, and then the adhesive is cured. Examples of the application method include roll coating methods such as reverse coating and gravure coating, spin coating, screen coating, fountain coating, dipping, and spraying.

[0074] The pressure-sensitive adhesive layer is a layer containing a pressure-sensitive adhesive, and a known pressure-sensitive adhesive layer can be used. Examples of pressure-sensitive adhesives contained in the pressure-sensitive adhesive layer include acrylic pressure-sensitive adhesives, epoxy pressure-sensitive adhesives, rubber pressure-sensitive adhesives, silicone pressure-sensitive adhesives, urethane pressure-sensitive adhesives, vinyl alkyl ether pressure-sensitive adhesives, polyvinyl alcohol pressure-sensitive adhesives, polyvinylpyrrolidone pressure-sensitive adhesives, polyacrylamide pressure-sensitive adhesives, and cellulose pressure-sensitive adhesives. Among these, acrylic pressure-sensitive adhesives (pressure-sensitive pressure-sensitive adhesives) are preferred because of their excellent transparency, weather resistance, heat resistance, etc.

[0075] As the acrylic adhesive, a copolymer of a (meth)acrylate in which the alkyl group in the ester moiety is an alkyl group having 20 or less carbon atoms, such as a methyl group, an ethyl group, or a butyl group, and a (meth)acrylic monomer having a functional group, such as (meth)acrylic acid and hydroxyethyl (meth)acrylate, is preferred. As the adhesive, the contents of

[0071] to

[0084] of JP 2018-60014 A can be referred to, and the contents thereof are incorporated herein by reference.

[0076] The method for forming the adhesive layer is not particularly limited, and examples thereof include a method in which a solution of the adhesive is applied to a release sheet, dried, and then transferred to at least one layer selected from the first optically anisotropic layer and the second optically anisotropic layer, and a method in which a solution in which the adhesive is dissolved or dispersed in a solvent (e.g., toluene and ethyl acetate) is applied to the surface of at least one layer selected from the first optically anisotropic layer and the second optically anisotropic layer and then dried. The application method can be the same as the application method for adhesives. Examples of materials constituting the release sheet include suitable thin sheets such as synthetic polymer films such as polyethylene, polypropylene, and polyethylene terephthalate; rubber sheets; paper; cloth; nonwoven fabrics; nets; foam sheets; and metal foils.

[0077] The isotropic layer A is preferably a pressure-sensitive adhesive layer or an ultraviolet-curable adhesive layer, and more preferably an ultraviolet-curable adhesive layer.

[0078] The thickness unevenness σ (unit: nm) of the isotropic layer A is often 100 nm or less, and is preferably 50 nm or less, more preferably 35 nm or less, and even more preferably 20 nm or less, from the viewpoint of more excellent effects of the present invention. Furthermore, the thickness unevenness σ of the isotropic layer A is preferably 5 nm or more, from the viewpoint of preventing air bubbles from being trapped when the first optically anisotropic layer and the second optically anisotropic layer are laminated together. That is, the thickness unevenness σ of the isotropic layer A is preferably 5 to 35 nm, more preferably 5 to 20 nm. The thickness unevenness σ of the isotropic layer A is a value calculated as the standard deviation of the thickness of the contact layer at 31 points obtained in the thickness measurement of the isotropic layer A described above. The method for adjusting the thickness unevenness of the isotropic layer A is not particularly limited, and examples include a method of adjusting the composition, viscosity, and coating method of the composition forming the isotropic layer A, and the conditions for laminating the first optically anisotropic layer and the second optically anisotropic layer via the isotropic layer A.

[0079] In-plane refractive index n of isotropic layer A Ａ is preferably 1.48 or more, more preferably 1.51 or more, still more preferably 1.53 or more, and particularly preferably 1.56 or more, in terms of more excellent effects of the present invention. Ａ is preferably 1.67 or less, more preferably 1.59 or less, and even more preferably 1.58 or less, in that the effects of the present invention are more excellent.

[0080] [Isotropic Layer B] The isotropic layer B may be any optically isotropic layer, and is preferably an adhesive layer. Examples of the adhesive layer include the same adhesive layers as the isotropic layer A. The isotropic layer B is preferably a pressure-sensitive adhesive layer or an ultraviolet-curable adhesive layer.

[0081] The thickness of the isotropic layer B is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 2 μm or more, in order to obtain a more excellent effect of the present invention. The thickness of the isotropic layer B is often 50 μm or less, preferably 20 μm or less, and more preferably 15 μm or less. The thickness of the isotropic layer B can be calculated in the same manner as the above-mentioned isotropic layer A.

[0082] The thickness unevenness σ (unit: nm) of the isotropic layer B is often 100 nm or less, and is preferably 50 nm or less, more preferably 35 nm or less, and even more preferably 20 nm or less, in order to achieve better effects of the present invention. The thickness unevenness σ of the isotropic layer B is preferably 5 nm or more, in order to prevent air bubbles from being trapped when the first optically anisotropic layer and the polarizer are bonded together. That is, the thickness unevenness σ of the isotropic layer B is preferably 5 to 35 nm, more preferably 5 to 20 nm. The thickness unevenness σ of the isotropic layer B is a value calculated as the standard deviation of the thickness of the contact layer at 31 points obtained in the thickness measurement of the isotropic layer B described above. The method for adjusting the thickness unevenness of the isotropic layer B is not particularly limited, and examples include adjusting the composition, viscosity, and coating method of the composition forming the isotropic layer B, and the conditions for laminating the first optically anisotropic layer and the polarizer via the isotropic layer B.

[0083] In-plane refractive index n of isotropic layer B Ｂ is preferably 1.48 or more, more preferably 1.51 or more, even more preferably 1.53 or more, and particularly preferably 1.56 or more, in terms of more excellent effects of the present invention. Ｂ is preferably 1.67 or less, more preferably 1.59 or less, and even more preferably 1.58 or less, in that the effects of the present invention are more excellent.

[0084] [Other Layers] The polarizer may include other layers in addition to those described above, as long as the other layers do not impair the functions of the present invention. Examples of the other layers include an alignment film, a substrate, and an optically anisotropic layer different from the first optically anisotropic layer and the second optically anisotropic layer.

[0085] <Alignment Film> The polarizing plate may have an alignment film. The alignment film may be disposed on a substrate described below or between optically anisotropic layers. The alignment film may be formed by rubbing an organic compound (preferably a polymer), oblique vapor deposition of an inorganic compound, formation of a layer with microgrooves, or accumulation of an organic compound (e.g., ω-tricosanoic acid, dioctadecylmethylammonium chloride, methyl stearate) using the Langmuir-Blodgett method (LB film). In addition to the above, the alignment film may exhibit alignment function upon application of an electric field, a magnetic field, or light irradiation (preferably polarized light). Examples of the alignment film include photo-alignment films. The thickness of the alignment film is not particularly limited as long as it can exhibit alignment function, but is preferably 0.01 to 5.0 μm, more preferably 0.05 to 3.0 μm, and even more preferably 0.5 to 1.0 μm. When the alignment film is disposed on a substrate, it may be peelable from the optically anisotropic layer together with the substrate.

[0086] <Substrate> The polarizing plate may have a substrate. The substrate is preferably a transparent substrate. The transparent substrate refers to a substrate having a visible light transmittance (average transmittance in the visible light region) of 60% or more, preferably 80% or more, and more preferably 90% or more. There is no particular upper limit, but 99.9% or less is preferred. There is no particular limit on the thickness of the substrate, but it is preferably 10 to 200 μm, more preferably 10 to 100 μm, and even more preferably 20 to 90 μm.

[0087] The substrate may contain various additives (for example, an optical anisotropy adjuster, a wavelength dispersion adjuster, fine particles, a plasticizer, an ultraviolet inhibitor, a deterioration inhibitor, a release agent, etc.) The thickness of the substrate is not particularly limited, but is preferably 10 to 200 μm, more preferably 10 to 100 μm, and even more preferably 20 to 90 μm.

[0088] The substrate may be composed of a plurality of laminated sheets. Furthermore, the surface of the substrate may be subjected to a surface treatment (e.g., glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, or flame treatment) to improve adhesion with a layer provided thereon. An adhesive layer (undercoat layer) may be provided on the substrate. Furthermore, a polymer layer containing 5 to 40% by mass of inorganic particles with an average particle size of approximately 10 to 100 nm mixed therein in a solid content ratio by mass may be disposed on one side of the substrate to impart slipperiness during the transport process or to prevent sticking of the back and front surfaces after winding.

[0089] The substrate may be a so-called temporary support, that is, after the polarizing plate of the present invention is produced on the substrate, the substrate may be peeled off from the optically anisotropic layer, if necessary.

[0090] When forming the above-described alignment film on the substrate surface, the surface of the substrate may be directly subjected to a rubbing treatment. That is, a substrate that has been subjected to a rubbing treatment may be used. The direction of the rubbing treatment is not particularly limited, and an optimal direction may be selected as appropriate depending on the direction in which the liquid crystal compound is desired to be aligned. The rubbing treatment may be a treatment method that is widely used as a liquid crystal alignment treatment process for LCDs (liquid crystal displays). That is, a method of obtaining alignment by rubbing the surface of the substrate in a certain direction using paper, gauze, felt, rubber, nylon fiber, polyester fiber, or the like may be used.

[0091] In the polarizing plate of the present invention, the combination of the first optically anisotropic layer and the second optically anisotropic layer may be appropriately selected, but a polarizing plate of the following Aspect 1 or Aspect 2 is preferred, with the polarizing plate of Aspect 1 being more preferred in that the color tone during black display can be further suppressed. (Aspect 1) The first optically anisotropic layer is a layer formed by fixing a vertically aligned discotic liquid crystal compound, and the second optically anisotropic layer is the optically anisotropic layer (AB). (Aspect 2) The first optically anisotropic layer is a layer formed by fixing a vertically aligned discotic liquid crystal compound or a layer formed by fixing a horizontally aligned rod-shaped liquid crystal compound, and the second optically anisotropic layer is the optically anisotropic layer (C). The definitions and preferred embodiments of the layer formed by fixing a vertically aligned discotic liquid crystal compound, the optically anisotropic layer (AB), the layer formed by fixing a horizontally aligned rod-shaped liquid crystal compound, and the optically anisotropic layer (C) in each aspect are as described above.

[0092] The polarizing plate of Aspect 1 described above will be described with reference to FIGS. 2 to 4. FIG. 2 is a schematic cross-sectional view of a polarizing plate 100A of Aspect 1. FIG. 3 is a diagram showing the relationship between the absorption axis of a polarizer 30A and the in-plane slow axes of the first optically anisotropic layer 10A and the optically anisotropic layer (A) 25A in the polarizing plate 100A of Aspect 1 shown in FIG. 2. Note that the arrows in the polarizer 30A in FIG. 3 represent the absorption axis, and the arrows in the first optically anisotropic layer 10A and the optically anisotropic layer (A) 25A represent the in-plane slow axes in the layers, respectively. FIG. 4 is a diagram showing the relationship between the absorption axis of the polarizer 30A (dashed line) and the in-plane slow axes (solid lines) of the first optically anisotropic layer 10A and the optically anisotropic layer (A) 25A when observed from the side indicated by the white arrow in FIG. 2. The rotation angle of the in-plane slow axis is expressed as a positive angle in the counterclockwise direction and a negative angle in the clockwise direction, with the absorption axis of polarizer 30A as the reference (0°) when observed from the side indicated by the white arrow in Fig. 2. The twist direction of the liquid crystal compound is determined as right-handed (clockwise) or left-handed (counterclockwise) based on the in-plane slow axis on the surface of optically anisotropic layer (A) 25A facing polarizer 30A when observed from the side indicated by the white arrow in Fig. 2.

[0093] 2, the polarizing plate 100A of the first embodiment has a polarizer 30A, a first optically anisotropic layer 10A, an isotropic layer A 40A, an optically anisotropic layer (A) 25A, and an optically anisotropic layer (B) 26A, in this order. A laminate of the optically anisotropic layer (A) 25A and the optically anisotropic layer (B) 26A constitutes a second optically anisotropic layer. The polarizing plate 100A may have an isotropic layer B (not shown) between the polarizer 30A and the first optically anisotropic layer 10A.

[0094] In the polarizing plate 100A of the first embodiment, as shown in Figures 3 and 4, the angle φa1 between the absorption axis of the polarizer 30A and the first optically anisotropic layer 10A is 76°. More specifically, the in-plane slow axis of the first optically anisotropic layer 10A is rotated by -76° (76° clockwise) with respect to the absorption axis of the polarizer 30. Although Figures 3 and 4 show an embodiment in which φa1 is 76°, the present invention is not limited to this embodiment, and φa1 is preferably 40 to 85°, more preferably 50 to 85°, and even more preferably 65 to 85°. Furthermore, as shown in Figure 3, in the first optically anisotropic layer 10A, the in-plane slow axis at the surface 101A of the first optically anisotropic layer 10A facing the polarizer 30A is parallel to the in-plane slow axis at the surface 102A of the first optically anisotropic layer 10A facing the optically anisotropic layer (A) 25A.

[0095] As shown in Figures 3 and 4, the in-plane slow axis of the optically anisotropic layer (A) 25A at its surface 251A facing the first optically anisotropic layer 10A is parallel to the in-plane slow axis of the first optically anisotropic layer 10A. As described above, the optically anisotropic layer (A) 25A is a layer formed by fixing rod-shaped liquid crystal compounds that are twisted and aligned with the thickness direction as the helical axis. Therefore, as shown in Figures 3 and 4, the in-plane slow axis of the optically anisotropic layer (A) 25A at its surface 251A facing the first optically anisotropic layer 10A and the in-plane slow axis of the surface 252A facing the optically anisotropic layer (B) 26A form the twist angle described above (81° in Figure 3). That is, the angle φa2 formed by the in-plane slow axis of the surface 251A of the optically anisotropic layer (A) 25A facing the first optically anisotropic layer 10A and the in-plane slow axis of the surface 252A facing the optically anisotropic layer (B) 26A is 81°. More specifically, the twist direction of the rod-shaped liquid crystal compound in the optically anisotropic layer (A) 14 is left-handed (counterclockwise), and the twist angle is 81°. While FIGS. 3 and 4 show an embodiment in which the twist angle of the rod-shaped liquid crystal compound in the optically anisotropic layer (A) 25A is 81°, the twist angle is not limited to this embodiment, and the twist angle of the rod-shaped liquid crystal compound is preferably 50 to 110°, more preferably 60 to 100°, and even more preferably 70 to 90°.

[0096] 3 and 4, the twist direction of the rod-shaped liquid crystal compound is counterclockwise as described in detail, but it may be clockwise as long as a predetermined angular relationship is satisfied. More specifically, when the polarizing plate 100A is observed from the polarizer 30A side, the in-plane slow axis of the first optically anisotropic layer 10A is rotated 76° counterclockwise with respect to the absorption axis of the polarizer 30A, and the twist direction of the rod-shaped liquid crystal compound in the optically anisotropic layer (A) 25A may be clockwise (right-handed twist).

[0097] That is, in polarizing plate 100A, when the in-plane slow axis of the first optically anisotropic layer rotates clockwise within a range of 40 to 85° (preferably 50 to 85°, more preferably 65 to 85°) with respect to the absorption axis of polarizer 30A, it is preferable that the twist direction of the rod-shaped liquid crystal compound in optically anisotropic layer (A) is counterclockwise with respect to the in-plane slow axis at the surface of optically anisotropic layer (A) facing the first optically anisotropic layer. Also, in polarizing plate 100A, when the in-plane slow axis of the first optically anisotropic layer rotates counterclockwise within a range of 40 to 85° (preferably 50 to 85°, more preferably 65 to 85°) with respect to the absorption axis of polarizer 30A, it is preferable that the twist direction of the rod-shaped liquid crystal compound in optically anisotropic layer (A) is clockwise with respect to the in-plane slow axis at the surface of optically anisotropic layer (A) facing the first optically anisotropic layer.

[0098] The polarizing plate of the second embodiment described above will be described with reference to FIGS. 5 to 7 . FIG. 5 is a schematic cross-sectional view of a polarizing plate 100B of the second embodiment. FIG. 6 is a diagram showing the relationship between the absorption axis of the polarizer 30B and the in-plane slow axes of the first optically anisotropic layer 10B and the optically anisotropic layer (C) 27B in the polarizing plate 100B of the second embodiment shown in FIG. 5 . Note that the arrows in the polarizer 30B in FIG. 6 represent the absorption axis, and the arrows in the first optically anisotropic layer 10B and the optically anisotropic layer (C) 27B represent the in-plane slow axes in the layers, respectively. FIG. 7 is a diagram showing the relationship between the absorption axis of the polarizer 30B (dashed line) and the in-plane slow axes (solid lines) of the first optically anisotropic layer 10B and the optically anisotropic layer (C) 27B when observed from the side indicated by the white arrow in FIG. 5 . The rotation angle of the in-plane slow axis is expressed as a positive angle in the counterclockwise direction and a negative angle in the clockwise direction when observed from the side indicated by the white arrow in Figure 5, with the absorption axis of polarizer 30B as the reference (0°).

[0099] 5, the polarizing plate 100B of the second embodiment includes a polarizer 30B, a first optically anisotropic layer 10B, an isotropic layer A 40B, and an optically anisotropic layer (C) 27B in this order. The polarizing plate 100B may include an isotropic layer B (not shown) between the polarizer 30B and the first optically anisotropic layer 10B.

[0100] In the polarizing plate 100B of the second embodiment, as shown in Figures 6 and 7, the angle φa3 between the absorption axis of the polarizer 30B and the first optically anisotropic layer 10B is 73°. More specifically, the in-plane slow axis of the first optically anisotropic layer 10B is rotated by -73° (73° clockwise) with respect to the absorption axis of the polarizer 30B. Although Figures 6 and 7 show an embodiment in which φa3 is 73°, the present invention is not limited to this embodiment, and φa3 is preferably 40 to 85°, more preferably 50 to 85°, and even more preferably 65 to 85°. Furthermore, as shown in Figure 6, in the first optically anisotropic layer 10B, the in-plane slow axis at the surface 101B on the polarizer 30B side of the first optically anisotropic layer 10B is parallel to the in-plane slow axis at the surface 102B on the optically anisotropic layer (C) 27B side of the first optically anisotropic layer 10B.

[0101] As shown in Figures 6 to 7, the angle φa4 between the in-plane slow axis of the first optically anisotropic layer 10B and the in-plane slow axis of the optically anisotropic layer (C) 27B is 58°. More specifically, the in-plane slow axis of the optically anisotropic layer (C) 27B is rotated by 58° (58° counterclockwise) with respect to the in-plane slow axis of the first optically anisotropic layer 10B. Although Figures 6 to 7 show an embodiment in which φa4 is 58°, the present invention is not limited to this embodiment, and φa4 is preferably 30 to 120°, more preferably 40 to 80°, and even more preferably 50 to 70°. As shown in FIG. 5, in the optically anisotropic layer (C) 27B, the in-plane slow axis at a surface 271 of the optically anisotropic layer (C) 27B facing the first optically anisotropic layer 10B is parallel to the in-plane slow axis at a surface 272 of the optically anisotropic layer (C) 27B facing away from the first optically anisotropic layer 10B.

[0102] 5 to 7 illustrate an embodiment in which the in-plane slow axis of the first optically anisotropic layer 10B rotates clockwise with respect to the absorption axis of the polarizer 30B when the polarizing plate 100B is observed from the polarizer 30B side, but the in-plane slow axis may rotate counterclockwise within a range of 40 to 85° (preferably 50 to 85°, more preferably 65 to 85°). For example, when the polarizing plate 100B is observed from the polarizer 30B side, if the in-plane slow axis of the first optically anisotropic layer 10B rotates counterclockwise within a range of 40 to 85° with respect to the absorption axis of the polarizer 30B, the in-plane slow axis of the optically anisotropic layer (C) 27B preferably rotates clockwise within a range of 60±30° with respect to the in-plane slow axis of the first optically anisotropic layer 10B.

[0103] [Method for manufacturing polarizing plate] The method for manufacturing a polarizing plate is not particularly limited. For example, a polarizer, a first optically anisotropic layer, and a second optically anisotropic layer are separately prepared, and then laminated in a predetermined direction via an isotropic layer to produce a polarizing plate. The method for manufacturing the polarizer is as described above. An example of the lamination method is a method in which adjacent layers are bonded together using an adhesive layer as an isotropic layer. The adhesive layer is not particularly limited, and examples thereof include the adhesive layers listed as the isotropic layer A and the isotropic layer B described above.

[0104] When the adhesive layer is an adhesive layer, it is preferable to subject the adhesive layer to a curing treatment after lamination. The curing method can be appropriately selected depending on the type of adhesive layer, and examples thereof include heat treatment and active energy ray irradiation treatment. Before forming and laminating the adhesive layer, each optically anisotropic layer (e.g., the first optically anisotropic layer and the second optically anisotropic layer) may be subjected to a surface treatment (e.g., glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, flame treatment) to improve adhesion.

[0105] The first and second optically anisotropic layers can be prepared using a composition for forming an optically anisotropic layer containing a liquid crystal compound. Hereinafter, a method for forming an optically anisotropic layer using the composition for forming an optically anisotropic layer will be described in detail.

[0106] [Method of Forming Optically Anisotropic Layer] The optically anisotropic layer can be formed using a composition for forming an optically anisotropic layer.

[0107] <Composition for forming an optically anisotropic layer> The liquid crystal compound contained in the composition for forming an optically anisotropic layer is the same as the liquid crystal compound contained in each of the optically anisotropic layers described above. As described above, a rod-shaped liquid crystal compound or a discotic liquid crystal compound is appropriately selected depending on the properties of the optically anisotropic layer to be formed. As described above, the liquid crystal compound is preferably a polymerizable liquid crystal compound having a polymerizable group. The polymerizable group is as described above. The content of the liquid crystal compound in the composition for forming an optically anisotropic layer is preferably 60 to 99% by mass, more preferably 70 to 98% by mass, based on the total solid content of the composition for forming an optically anisotropic layer. Note that the solid content refers to components capable of forming an optically anisotropic layer from which the solvent has been removed, and is considered to be solid content even if the component is in a liquid state.

[0108] The composition for forming an optically anisotropic layer may contain compounds other than the liquid crystal compound, such as a chiral agent, a photoalignment compound (photoalignment polymer), a polymerization initiator, a polyfunctional monomer, an alignment control agent (vertical alignment agent, horizontal alignment agent), a leveling agent, a surfactant, an adhesion improver, a plasticizer, and a solvent.

[0109] For example, the composition for forming the optically anisotropic layer (A) preferably contains a chiral agent to twist the liquid crystal compound. Note that when the liquid crystal compound is an optically active compound, such as one having an asymmetric carbon in the molecule, the addition of a chiral agent is unnecessary. Also, depending on the production method and twist angle, the addition of a chiral agent is unnecessary. The chiral agent is not particularly limited as long as it is compatible with the liquid crystal compound used in combination, and known chiral agents can be used, and may be appropriately selected depending on the sense and pitch of the desired helix. Examples of chiral agents that can be used include compounds described in "Liquid Crystal Device Handbook" (Chapter 3, Section 4-3, Chiral Agents for TN and STN, p. 199, edited by the 142nd Committee of the Japan Society for the Promotion of Science, 1989), and in JP-A Nos. 2003-287623, 2002-302487, 2002-080478, 2002-080851, 2010-181852, and 2014-034581. Of these, preferred chiral agents are compounds selected from the group consisting of isosorbide derivatives, isomannide derivatives, and binaphthyl derivatives. Commercially available isosorbide derivatives, such as LC-756 manufactured by BASF, may also be used.

[0110] The chiral agent may have a polymerizable group. Examples of the polymerizable group that the chiral agent may have include the polymerizable groups that the liquid crystal compound may have, and preferred embodiments are also the same as those described above.

[0111] The content of the chiral dopant is preferably 0.01 to 200 mol %, more preferably 1 to 30 mol %, based on the content of the liquid crystal compound.

[0112] The photo-alignable compound is a compound having a photo-alignable group, and the photo-alignable group can be aligned in a predetermined direction by light irradiation. As the photo-alignable compound, a photo-alignable polymer is preferred. The photo-alignable polymer is not particularly limited as long as it is compatible with the liquid crystal compound used in combination, and known photo-alignable polymers can be used.

[0113] The composition for forming an optically anisotropic layer may contain a polymerization initiator. The polymerization initiator to be used is selected depending on the type of polymerization reaction, and examples thereof include a thermal polymerization initiator and a photopolymerization initiator. The content of the polymerization initiator in the composition for forming an optically anisotropic layer is preferably 0.01 to 20% by mass, more preferably 0.5 to 10% by mass, based on the total solid content of the composition for forming an optically anisotropic layer.

[0114] <Procedure for Forming Optically Anisotropic Layer> The procedure for forming the optically anisotropic layer is not particularly limited, and examples thereof include a method including, in this order, a coating step of applying the above-described optically anisotropic layer-forming composition to a substrate, an alignment step of applying an alignment treatment to the formed coating film to align the liquid crystal compound, and an alignment fixing step of applying a curing treatment to fix the liquid crystal compound. The substrate may be a substrate that may be included in the above-described polarizing plate. The optically anisotropic layer may be formed directly on the optically anisotropic layer using the optically anisotropic layer-forming composition. By applying the optically anisotropic layer-forming composition to the prepared optically anisotropic layer and then performing a predetermined treatment to form the optically anisotropic layer, a laminate in which two or more optically anisotropic layers are directly laminated without an adhesive layer can be produced. When forming the optically anisotropic layer directly on the optically anisotropic layer using the optically anisotropic layer-forming composition, a treatment to form an alignment film may be performed on the surface of the optically anisotropic layer before applying the optically anisotropic layer-forming composition.

[0115] The coating method in the coating step is not particularly limited, and examples thereof include extrusion coating, curtain coating, dip coating, spin coating, print coating, spray coating, slot coating, roll coating, slide coating, blade coating, gravure coating, die coating, and wire bar coating. If necessary, after coating the composition for forming an optically anisotropic layer, a treatment for drying the coating film coated on the substrate may be carried out. The drying treatment can remove the solvent from the coating film. The thickness of the coating film is not particularly limited, but is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, and even more preferably 0.5 to 10 μm.

[0116] The alignment treatment in the alignment step can be carried out by drying the coating film at room temperature or by heating the coating film. In the case of a thermotropic liquid crystal compound, the liquid crystal phase formed by the alignment treatment can generally be transitioned by a change in temperature or pressure. In the case of a lyotropic liquid crystal compound, the transition can also be achieved by adjusting the composition ratio, such as the amount of solvent. The conditions for heating the coating film are not particularly limited, but the heating temperature is preferably 50 to 250°C, more preferably 50 to 150°C, and the heating time is preferably 10 seconds to 10 minutes. After heating the coating film, the coating film may be cooled, if necessary, before the curing treatment (light irradiation treatment) described below. The cooling temperature is preferably 20 to 200°C, more preferably 30 to 150°C.

[0117] When the composition for forming an optically anisotropic layer contains a photoalignable polymer, it is preferable to subject the composition to a photoalignment treatment in order to impart alignment controllability. Examples of the photoalignment treatment include a method of irradiating a coating film (including a cured film) of the polymerizable liquid crystal composition with polarized light and a method of irradiating the coating film surface with non-polarized light from an oblique direction.

[0118] The wavelength of the polarized or unpolarized light is not particularly limited as long as it is light to which the photo-alignable group is photosensitive, and examples thereof include ultraviolet light, near ultraviolet light, and visible light, with near ultraviolet light of 250 to 450 nm being preferred. Examples of light sources for irradiating polarized or unpolarized light include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps. The wavelength range of the irradiated ultraviolet or visible light obtained from the light source can be limited by using an interference filter or color filter. Linearly polarized light can be obtained by using a polarizing filter or polarizing prism on the light from these light sources.

[0119] The integrated amount of polarized or unpolarized light is not particularly limited, and is 1 to 300 mJ / cm ２ is preferred, and 5 to 100 mJ / cm ２ The illuminance of polarized or unpolarized light is not particularly limited, and is 0.1 to 300 mW / cm ２ is preferred, and 1 to 100 mW / cm ２is more preferred.

[0120] The method of curing in the orientation fixing step is not particularly limited, and examples thereof include light irradiation and heat treatment. Among these, from the viewpoint of manufacturability, light irradiation is preferred, and ultraviolet irradiation is more preferred. The irradiation conditions for the light irradiation are not particularly limited, but are preferably 50 to 1000 mJ / cm. ２ The atmosphere during the light irradiation treatment is not particularly limited, but a nitrogen atmosphere is preferred.

[0121] <Method of Forming Optically Anisotropic Layer Having Specific Region> The method of forming the optically anisotropic layer having the specific region described above is not particularly limited, and examples thereof include Method 1 and Method 2 shown below.

[0122] (Method 1) Method 1 uses a photoisomerizable liquid crystal compound having a photoisomerizable moiety. More specifically, Method 1 includes the above-described coating film formation step, alignment step, and alignment fixing step, in this order, and uses a composition containing a photoisomerizable liquid crystal compound as the composition for forming an optically anisotropic layer. It also includes an isomerization step between the alignment step and the alignment fixing step, in which the photoisomerizable liquid crystal compound is isomerized. The photoisomerizable liquid crystal compound undergoes photoisomerization within the coating film of the composition for forming an optically anisotropic layer, resulting in a change in its three-dimensional structure and a change in its optical properties (e.g., birefringence). By utilizing the phenomenon in which light intensity attenuates in the thickness direction when light is irradiated from the surface, the proportion of photoisomerizable liquid crystal compounds can be reduced from the surface side along the thickness direction. Therefore, a specific region in which in-plane birefringence gradually increases along the thickness direction can be formed by forming a coating film using a composition for forming an optically anisotropic layer containing a photoisomerizable liquid crystal compound, orienting the liquid crystal compound, and then irradiating light from at least one surface to photoisomerize the photoisomerizable liquid crystal compound.

[0123] When the optically anisotropic layer is any layer selected from an A plate, a C plate, and a chiral nematic phase, an optically anisotropic layer having a specific region can be suitably formed by Method 1. A C plate is a plate that satisfies either of the following formulas (C1) and (C2), where nx is the refractive index in the in-plane slow axis direction, ny is the refractive index in the direction perpendicular to the in-plane slow axis, and nz is the refractive index in the thickness direction. When formula (C1) is satisfied, it is a so-called positive C plate, and when formula (C2) is satisfied, it is a so-called negative C plate. Note that a positive C plate has a negative Rth, and a negative C plate has a positive Rth. Formula (C1) nz>nx≒ny Formula (C2) nz<nx≒ny Note that the above "≒" includes not only the case where both are completely identical, but also the case where both are substantially identical. The term "substantially the same" includes, for example, the case where (nx-ny) x d (where d is the thickness of the film) is 0 to 10 nm, preferably 0 to 5 nm, in "nx≈ny".

[0124] -Photoisomerizable Liquid Crystal Compound- As described above, a photoisomerizable liquid crystal compound is a compound having a photoisomerizable moiety that is isomerized by light and changes its three-dimensional structure. A representative example of the photoisomerization is cis-trans photoisomerization of a carbon-carbon double bond. Specific examples of the photoisomerizable moiety include cinnamoyl, chalcone, and stilbene. The photoisomerizable liquid crystal compound is preferably a compound whose birefringence decreases upon photoisomerization. The photoisomerization wavelength of the photoisomerizable liquid crystal compound is preferably different from the wavelength of light used in the alignment fixing step described above.

[0125] The photoisomerizable liquid crystal compound may be either a rod-shaped liquid crystal compound or a discotic liquid crystal compound. The photoisomerizable liquid crystal compound is preferably a compound having a cinnamoyl moiety represented by the following formula (W-1) or a compound having a stilbene moiety represented by the following formula (W-2) as a photoisomerizable moiety. The benzene ring in the following formulas (W-1) and (W-2) may have a substituent. In the following formulas (W-1) and (W-2), * represents a bonding position.

[0126]

[0127] The photoisomerizable rod-shaped liquid crystal compound preferably has a photoisomerizable moiety in the mesogen. Examples of the photoisomerizable rod-shaped liquid crystal compound include compounds represented by formula (A1). １ -SP １ -(Cy １ -L １ ) ｎ１ -W-(L ２ -Cy ２ ) ｎ２ -SP ２ -P １ Formula (A1)

[0128] In formula (A1), P １ and P ２ each independently represents a polymerizable group. The polymerizable group is preferably a functional group capable of undergoing an addition polymerization reaction, more preferably a polymerizable ethylenically unsaturated group or a ring-polymerizable group, and still more preferably a (meth)acryloyl group, a (meth)acryloyloxy group, a (meth)acrylamide group, a vinyl group, a styryl group, or an allyl group.

[0129] In formula (A1), SP １ and SP ２ each independently represents a spacer group. The spacer group is not particularly limited as long as it is a divalent linking group that does not contain a ring structure, and examples thereof include divalent chain aliphatic hydrocarbon groups having 1 to 20 carbon atoms. The divalent chain aliphatic hydrocarbon group having 1 to 20 carbon atoms is preferably an alkylene group having 1 to 15 carbon atoms, more preferably an alkylene group having 1 to 8 carbon atoms. The —CH ２ One or more of the - may be independently substituted with a group selected from -O-, -S-, -CO-, and -N(Q)-. ２ - may be substituted. Q represents a hydrogen atom or a substituent. The substituent represented by Q is preferably an alkyl group, more preferably a linear alkyl group having 1 to 4 carbon atoms, and even more preferably a methyl group or an ethyl group. Among others, the spacer group is preferably *-(CH ２ -CH ２ -O)ｎｓ１ -*, *-(CH ２ ) ｎｓ２ -O-*, or *-(CH ２ ) ｎｓ２ -O-CO-* is preferred. * represents the bonding position. ns1 represents an integer of 1 to 4. Each ns2 independently represents an integer of 1 to 6, preferably an integer of 2 to 4.

[0130] In formula (A1), Cy １ and Cy ２ each independently represents a divalent cyclic group which may have a substituent. The divalent cyclic group may be either a monocyclic or polycyclic group, and is preferably a monocyclic group. The number of ring members in the divalent cyclic group is preferably 5 to 18, more preferably 5 to 10, and even more preferably 5 or 6.

[0131] Examples of the divalent ring group include a divalent aromatic ring group and a divalent alicyclic group. Examples of the divalent aromatic ring group include a divalent aromatic hydrocarbon ring group obtained by removing two hydrogen atoms from an aromatic hydrocarbon ring, and a divalent aromatic heterocyclic group obtained by removing two hydrogen atoms from an aromatic heterocyclic ring. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthroline ring. Examples of the aromatic heterocyclic ring include a pyridine ring, a pyridazine ring, an imidazole ring, a thiophene ring, a quinoline ring, an isoquinolylene ring, an oxazole ring, a thiazole ring, an oxadiazole ring, a benzothiazole ring, a benzothiadiazole ring, a phthalimide ring, a thienothiazole ring, a thiazolothiazole ring, a thienothiophene ring, and a thienoxazole ring. Among these, a group obtained by removing two hydrogen atoms from a benzene ring (for example, a 1,4-phenylene group) is preferred. Examples of the divalent alicyclic group include a divalent aliphatic hydrocarbon ring group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring (e.g., a cycloalkane or a cycloalkene), and a divalent aliphatic heterocyclic group obtained by removing two hydrogen atoms from an aliphatic heterocyclic ring. Examples of the aliphatic hydrocarbon ring include a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a cyclononane ring, a cyclododecane ring, and a cyclodocosane ring. Examples of the aliphatic heterocyclic group include a pyrrolidine ring, an oxolane ring, a thiolane ring, a piperidine ring, a tetrahydropyran ring, a thiane ring, a piperazine ring, and a morpholine ring. Among these, a group obtained by removing a divalent hydrogen atom from a cyclohexane ring (e.g., a 1,4-cyclohexylene group) is preferred. Examples of the divalent ring group include a divalent aromatic ring group or a divalent aliphatic hydrocarbon ring group, and a divalent aromatic ring group is more preferred.

[0132] Examples of the substituent that the divalent cyclic group may have include an alkyl ester group, an alkyl group which may have a halogen atom, an acyl group, an alkoxy group, an alkylthio group, an alkyloxycarbonyl group, a carbamoyl group, an acylamino group, a halogen atom, a cyano group, and a nitro group. An alkyl ester group, an alkyl group, or an acyl group is preferred, a methyl ester group, a linear alkyl group having 1 to 4 carbon atoms, or an acetyl group is more preferred, and a methyl ester group, a methyl group, or an ethyl group is even more preferred.

[0133] In formula (A1), L １ and L ２ each independently represents a single bond or a divalent linking group. Examples of the divalent linking group include -CO-, -O-, -S-, -C(=S)-, and -CR Ｌ１ R Ｌ２ -, -CR Ｌ３ =CR Ｌ４ - and -NR Ｌ５ -, and combinations of two or more thereof. Ｌ１ ~R Ｌ５ R each independently represents a hydrogen atom or a substituent. Ｌ１ ~R Ｌ５ The substituent represented by is preferably a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. １１ Examples thereof include —CO—, —O—, and —CR Ｌ１ R Ｌ２ -, -NR Ｌ５ - or a combination of the two is preferred.

[0134] In formula (A1), n1 and n2 each independently represent an integer of 0 or greater. The sum of n1 and n2 is preferably an integer of 1 to 10, more preferably an integer of 1 to 3, and even more preferably 1.

[0135] In formula (A1), W represents a group represented by formula (W-1) or a group represented by formula (W-2) described above, and is preferably a group represented by formula (W-1).

[0136] Specific examples of the photoisomerizable rod-shaped liquid crystal compound include the compounds shown below.

[0137]

[0138] The photoisomerizable discotic liquid crystal compound preferably has a photoisomerizable moiety adjacent to the mesogenic moiety of the discotic liquid crystal compound. Examples of the photoisomerizable discotic liquid crystal compound include compounds represented by formula (A2). １ - (L ３ -W-L ４ -P ３ )m Formula (A2)

[0139] In formula (A2), M １ represents an m-valent discotic mesogenic group. Examples of the m-valent discotic mesogenic group include known discotic mesogenic groups, such as the mesogenic groups contained in the discotic liquid crystal compounds described in JP-A-2007-108732 and JP-A-2010-244038.

[0140] In formula (A2), L ３ and L ４ each independently represents a single bond or a divalent linking group. ３ and L ４ In formula (A1), the divalent linking group represented by L １ and L ２ Examples of the divalent linking group represented by the formula: ３ is preferably a single bond. ４ Examples thereof include —CO—, —O—, and —CR Ｌ１ R Ｌ２ -, -NR Ｌ５ - or a combination thereof is preferred.

[0141] In formula (A2), P ３ each independently represents a polymerizable group. ３ The definition and preferred embodiments of the polymerizable group represented by the formula (A1) are as follows: １ and P ２ is the same as the polymerizable group represented by the following formula:

[0142] In formula (A2), m represents an integer of 3 or greater. m is preferably an integer of 3 to 10, and more preferably an integer of 4 to 8.

[0143] In formula (A2), W represents a group represented by formula (W-1) or a group represented by formula (W-2) described above, and is preferably a group represented by formula (W-1).

[0144] Specific examples of the photoisomerizable discotic liquid crystal compound include the compounds shown below.

[0145]

[0146] The photoisomerizable liquid crystal compound may be used alone or in combination of two or more. When forming an optically anisotropic layer having a specific region using Method 1, a liquid crystal compound not having a photoisomerizable moiety may be used in combination with a photoisomerizable liquid crystal compound. The content of the photoisomerizable liquid crystal compound can be appropriately adjusted depending on the thickness of the desired specific region, etc. The content of the photoisomerizable liquid crystal compound is preferably 10 to 100% by mass, more preferably 30 to 100% by mass, based on the total amount of liquid crystal compounds. The content of the photoisomerizable liquid crystal compound is preferably 30 to 98% by mass, more preferably 60 to 95% by mass, based on the total solid content of the composition for forming an optically anisotropic layer.

[0147] The light that isomerizes the photoisomerizable liquid crystal compound is not particularly limited, but is preferably different from the light used in the alignment step and alignment fixing step. Examples of wavelengths of light that isomerize the photoisomerizable liquid crystal compound include ultraviolet light, near-ultraviolet light, and visible light, with light with a wavelength of 300 to 330 nm being preferred. The conditions for irradiating the light are not particularly limited, and can be adjusted depending on the type and concentration of the photoisomerizable liquid crystal compound used, as well as the desired thickness of the specific region. The dose of light and the thickness of the specific region can be determined, for example, using the Beer-Lambert law. The dose of light irradiation treatment is, for example, 10 to 500 mJ / cm. ２ In most cases, it is 30 to 200 mJ / cm ２ This is more common.

[0148] When a specific region is formed on one surface of the optically anisotropic layer, the coating film of the composition for forming an optically anisotropic layer is irradiated with light from one surface side (preferably the surface opposite the substrate side) to cause photoisomerization, thereby forming an optically anisotropic layer having a specific region on one surface.When a specific region is formed on both surfaces of the optically anisotropic layer, the coating film of the composition for forming an optically anisotropic layer is irradiated with light from both the surface facing the substrate and the surface opposite the substrate side, thereby forming an optically anisotropic layer having a specific region on both surfaces.

[0149] (Method 2) Method 2 is a method that uses an optically anisotropic layer-forming composition that contains a surfactant having a mesogen group. In other words, Method 2 is a method that includes the above-mentioned coating film formation step, alignment step, and alignment fixing step, in this order, and uses an optically anisotropic layer-forming composition that contains a surfactant having a mesogen group as the optically anisotropic layer-forming composition. Since the surfactant that is unevenly distributed on the surface side of the coating film of the optically anisotropic layer-forming composition has a predetermined mesogen group, the orientation of the liquid crystal compound changes from the surface side of the coating film along the thickness direction, and a specific region in which the in-plane birefringence gradually increases along the thickness direction can be formed.

[0150] When the optically anisotropic layer is in a chiral nematic phase, an optically anisotropic layer having a specific region on one side can be suitably formed by Method 2. For example, when the composition for forming an optically anisotropic layer that forms a chiral nematic phase contains a surfactant having a vertically oriented mesogenic group, the rod-shaped liquid crystal compounds that were oriented horizontally with respect to the main surface while twisting with the thickness direction as the helical axis assume a twisted orientation such that they are oriented vertically toward the surface side, and as a result, the in-plane birefringence gradually decreases from the region where the rod-shaped liquid crystal compounds are oriented horizontally toward the surface side.

[0151] Examples of surfactants having a mesogenic group include a repeating unit having a ubiquitous group and a polymer having a repeating unit having a mesogenic group.

[0152] The repeating unit containing an ubiquitous group refers to a group that is unevenly distributed on the air-interface side of a coating film formed using a composition containing a compound having the ubiquitous group. Examples of the ubiquitous group include a group containing a fluorine atom and a group containing a silicon atom.

[0153] Examples of groups containing a fluorine atom include alkyl groups (fluoroalkyl groups) in which at least one hydrogen atom is substituted with a fluorine atom, and alkenyl groups (fluoroalkenyl groups) in which at least one hydrogen atom is substituted with a fluorine atom, with fluoroalkyl groups being preferred. The fluoroalkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10. The fluoroalkenyl group preferably has 2 to 20 carbon atoms, more preferably 2 to 10. The fluoroalkyl group and fluoroalkenyl group preferably have 1 to 25 fluorine atoms, more preferably 3 to 21, and even more preferably 5 to 21.

[0154] The group containing a fluorine atom is preferably a group represented by formula (F1): *—(CH ２ ) ｍａ (CF ２ ) ｍｂ CF ２ X Formula (F1) In formula (F1), * represents a bonding position. ma and mb each independently represent an integer of 0 or more. ma is preferably an integer of 0 to 10, more preferably an integer of 0 to 6, and still more preferably an integer of 1 to 3. mb is preferably an integer of 0 to 12, more preferably an integer of 0 to 8, still more preferably an integer of 0 to 5, and particularly preferably an integer of 3 to 5. X represents a hydrogen atom or a fluorine atom, and a fluorine atom is preferred.

[0155] The silicon atom-containing group is preferably a group represented by formula (S1): ｓ１ -(SiR １１ R １２ R １３ ) ｍｓ Formula (S1)

[0156] In formula (S1), * represents a bonding position.

[0157] In formula (S1), L ｓ１represents a ms+1 valent linking group. Suitable examples of the ms+1 valent linking group include ms+1 valent hydrocarbon groups having 1 to 10 carbon atoms which may have a substituent, in which some of the carbon atoms constituting the hydrocarbon group may be substituted with heteroatoms. The substituent that the hydrocarbon group may have is preferably an alkyl group, more preferably a linear alkyl group having 1 to 4 carbon atoms, and even more preferably a methyl group or an ethyl group. Examples of the heteroatom that may substitute some of the carbon atoms include a silicon atom, an oxygen atom, and a nitrogen atom. L ｓ１ Examples of the group include a group represented by the following structural formula K-1-L, a group represented by the structural formula K-2-L, and a group represented by the structural formula K-3-L. In the sub-structural formulas, * represents * in formula (S1), and ** represents -SiR in formula (S1). １１ R １２ R １３ represents the bonding position with the group represented by the formula:

[0158]

[0159] In formula (S1), R １１ , R １２ , and R １３ each independently represents an alkyl group, alkenyl group, aryl group, or alkylenearyl group, which may have a substituent. The substituent is preferably a halogen atom, an alkyl group, an alkylcarbonyl group, an alkyloxycarbonyl group, an alkylcarbonyloxy group, or an alkoxy group. Examples of the alkyl group include a linear alkyl group having 1 to 18 carbon atoms, and a branched or cyclic alkyl group having 3 to 18 carbon atoms. Examples of the alkenyl group include an alkenyl group having 2 to 12 carbon atoms. Examples of the aryl group include an aryl group having 6 to 12 carbon atoms. Examples of the alkylenearyl group include an alkylenearyl group having 7 to 30 carbon atoms. R １１ , R １２ , and R １３ are preferably all alkyl groups.

[0160] The repeating unit having a localized group is preferably a repeating unit represented by the following formula (B1).

[0161]

[0162] In formula (B1), R ２１ and R ２２ R each independently represents a hydrogen atom or an alkyl group. Examples of the alkyl group include a linear alkyl group having 1 to 18 carbon atoms and a branched or cyclic alkyl group having 3 to 18 carbon atoms. ２１ and R ２２ is preferably a hydrogen atom.

[0163] In formula (B1), R ２３ represents a hydrogen atom or a substituent. Examples of the substituent include an alkyl group, an alkenyl group, an aryl group, a group represented by formula (F1), and a group represented by formula (S1). R ２３ is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a linear alkyl group having 1 to 4 carbon atoms, still more preferably a hydrogen atom, a methyl group, or an ethyl group, and particularly preferably a hydrogen atom or a methyl group.

[0164] In formula (B1), L Ｂ１ represents a single bond, —O—, or —NR Ｚ - represents. Ｚ represents a hydrogen atom or a substituent. Ｚ Examples of the substituent represented by the formula: ２３ Examples of the substituent represented by the formula (I) include the groups exemplified above, and an alkyl group is preferred, a linear alkyl group having 1 to 4 carbon atoms is more preferred, and a methyl group or an ethyl group is even more preferred. Ｂ１ As the group, —O— or —NH— is preferable, and —O— is more preferable.

[0165] In formula (B1), X Ｂ１ represents a ubiquitous group. The definition of the ubiquitous group is as described above, and the ubiquitous group is preferably a group containing a fluorine atom or a group containing a silicon atom, and more preferably a group represented by formula (F1) or a group represented by formula (S1).

[0166] The repeating unit having a unidirectional group may be used alone or in combination of two or more. The content of the repeating unit having a unidirectional group is preferably 10 to 90 mass %, more preferably 15 to 80 mass %, and even more preferably 20 to 70 mass %, based on all repeating units (100 mass %) constituting the main chain of the surfactant.

[0167] -Repeating unit containing a mesogen group- The mesogen group in the repeating unit containing a mesogen group is not particularly limited, and known mesogen groups can be used. For example, reference can be made to the description in "Flussige Kristalle in Tabellen II" (VEB Deutsche Verlag fur Grundstoff Industrie, Leipzig, published in 1984), particularly pages 7 to 16, and the description in "Liquid Crystal Handbook" edited by the Liquid Crystal Handbook Editorial Committee (Maruzen, published in 2000), particularly Chapter 3.

[0168] The mesogenic group is preferably a group having at least one cyclic structure selected from the group consisting of an aromatic hydrocarbon group, a heterocyclic group, and an alicyclic group. The mesogenic group is preferably a group having an aromatic hydrocarbon group or an alicyclic group, which may have a substituent, because this improves the degree of alignment of the liquid crystal compound. A group having two to four aromatic hydrocarbon groups, which may have a substituent, is more preferred, and a group having three aromatic hydrocarbon groups, which may have a substituent, is even more preferred. The substituent is preferably an alkyl group, an alkoxy group, an alkyl ester group, or an acetyl group, and more preferably a methyl group, a tert-butyl group, a methoxy group, or a methyl ester group.

[0169] The mesogenic group is preferably a group represented by the following formula (M1): １１ -L １１ ) ｎｍ -Cy １２ -* (M1) In formula (M1), * represents a bonding position. nm represents an integer of 1 or more, preferably an integer of 1 to 10, more preferably an integer of 1 to 3, and even more preferably 2. Cy １１ and Cy １２each independently represents a divalent ring group which may have a substituent. １１ and Cy １２ The definition and preferred embodiments of the group represented by the formula (A1) are as follows: １ and Cy ２ It is the same as L １１ represents a single bond or a divalent linking group. １１ The definition and preferred embodiments of the group represented by the formula (A1) are as follows: １ and L ２ is the same as

[0170] The repeating unit having a mesogenic group is preferably a repeating unit represented by the following formula (C1) or a repeating unit represented by formula (C2). The mesogenic group in the repeating unit represented by formula (C1) is aligned vertically to the main surface, and the mesogenic group in the repeating unit represented by formula (C2) is aligned horizontally to the main surface. In terms of the ability to form a specific region, the surfactant preferably has a repeating unit represented by formula (C1).

[0171]

[0172] In formulas (C1) and (C2), R ２１ , R ２２ , R ２３ , and L Ｂ１ is the same as that explained in the above formula (B1). ２４ and R ２５ are each independently R in the above formula (B1). ２１ and R ２２ The definition and preferred embodiments are the same as those of R. ２６ is R in the above formula (B1). ２３ The definition and preferred embodiments are the same as those of the above. Ｂ２ is L in the above formula (B1). Ｂ１ The definitions are the same as those of the above, and preferred embodiments are also the same.

[0173] In formulas (C1) and (C2), SP Ｃ１ and SP Ｃ２ each independently represents a spacer group. Ｃ１ and SPＣ２ The definition and preferred embodiments of the spacer group represented by the formula (A1) are １ and SP ２ In formula (C1) and formula (C2), M １ represents a mesogenic group. Details of the mesogenic group are as described above.

[0174] In formula (C2), T １ represents a terminal group. The terminal group represents a hydrogen atom or a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkoxycarbonyloxy group having 1 to 10 carbon atoms, an alkoxycarbonyl group having 1 to 10 carbon atoms (ROC(O)-: R is an alkyl group), an acyloxy group having 1 to 10 carbon atoms, an acylamino group having 1 to 10 carbon atoms, an alkoxycarbonylamino group having 1 to 10 carbon atoms, a sulfonylamino group having 1 to 10 carbon atoms, a sulfamoyl group having 1 to 10 carbon atoms, a carbamoyl group having 1 to 10 carbon atoms, a sulfinyl group having 1 to 10 carbon atoms, a trialkylsilyloxy group having 3 to 12 carbon atoms, a ureido group having 1 to 10 carbon atoms, and a (meth)acryloyloxy group-containing group. Examples of the (meth)acryloyloxy group-containing group include -L Ａ -A (L Ａ represents a single bond or a divalent linking group. The divalent linking group may be any of the above-mentioned L １ A represents a (meth)acryloyloxy group). １ Examples of the boronic acid group include: ２ ) and a boronic ester group (—B(R Ｂ１ ) ２ ) can also be mentioned. Ｂ１R each independently represent a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heteroaryl group which may have a substituent, and a hydrogen atom or an alkyl group which may have a substituent is preferred. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms. The aryl group preferably has 4 to 20 carbon atoms, more preferably 6 to 12 carbon atoms. An example of an aryl group is a phenyl group. The heteroaryl group preferably has 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms. Examples of heteroatoms contained in the heteroaryl group include an oxygen atom, a nitrogen atom, and a sulfur atom. Ｂ１ R may be bonded to each other to form a ring. Ｂ１ The number of members in the ring formed by bonding together is preferably 4 to 8, and more preferably 5 to 6.

[0175] The repeating unit having a mesogen group may be used alone or in combination of two or more. The content of the repeating unit having a mesogen group is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, and even more preferably 15 to 60% by mass, based on all repeating units (100% by mass) constituting the main chain of the surfactant.

[0176] The surfactant having a mesogenic group may have other repeating units in addition to those described above, such as a repeating unit having a polymerizable group and a repeating unit having an acid group.

[0177] The surfactant having a mesogen group may be used alone or in combination of two or more. When forming an optically anisotropic layer having a specific region using Method 2, a surfactant not having a mesogen group may be used in combination with a surfactant having a mesogen group. In terms of the alignment of the optically anisotropic layer, it is also preferable to use, as the surfactant having a mesogen group, a surfactant having a vertically aligning mesogen group (e.g., a surfactant having a repeating unit represented by Formula (C1)) and a surfactant having a horizontally aligning mesogen group (e.g., a surfactant having a repeating unit represented by Formula (C2)) in combination.

[0178] [Uses] The polarizing plate of the present invention can be suitably applied to a display device. The display device of the present invention includes a display element and the polarizing plate of the present invention. The polarizing plate is usually provided on the viewing side of the display device. In this case, the polarizer in the polarizing plate is arranged on the viewing side. The display element is not particularly limited, and examples thereof include an organic electroluminescence display element (organic EL display element) and a liquid crystal display element.

[0179] The organic electroluminescence display element is a member in which a light-emitting layer or a plurality of organic compound thin films including a light-emitting layer are formed between a pair of electrodes, an anode and a cathode, and may have a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, and / or a protective layer in addition to the light-emitting layer, and each of these layers may have other functions. Various materials can be used to form each layer.

[0180] The present invention will be described in more detail below with reference to the following examples. The materials, amounts used, ratios, treatment details, and treatment procedures shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the following examples.

[0181] [Example 1] [Preparation of Cellulose Acylate Film (Substrate)] The following composition (cellulose acylate dope) was charged into a mixing tank, stirred, and further heated at 90°C for 10 minutes. Thereafter, the obtained composition was filtered through a filter paper having an average pore size of 34 μm and a sintered metal filter having an average pore size of 10 μm to prepare a dope. The solid content concentration of the dope was 23.5 mass%, the amount of plasticizer added was the ratio relative to the cellulose acylate, and the solvent for the dope was methylene chloride / methanol / butanol = 81 / 18 / 1 (mass ratio).

[0182] ------------------------------- Cellulose acylate dope -------------------------------- Cellulose acylate (acetyl substitution degree 2.86, viscosity average polymerization degree 310) 100 parts by mass Compound 1 (shown in the following formula (S4)) 8.0 parts by mass Compound 2 (shown in the following formula (S5)) 2.0 parts by mass Compound 3 (shown in the following formula (S6)) 0.2 parts by mass Compound 4 (shown in the following formula (S7)) 0.02 parts by mass Silica particle dispersion (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 0.1 part by mass Solvent (methylene chloride / methanol / butanol) --------------------------------

[0183]

[0184]

[0185]

[0186]

[0187] The dope prepared above was cast using a band film-forming machine. The dope was cast from a die onto a metal support, and then the resulting web (film) was peeled off. The drum was made of SUS.

[0188] The web (film) obtained by casting was peeled from the drum and then dried for 20 minutes in a tenter apparatus, in which both ends of the web were clipped with clips while the film was being transported at 30 to 40°C. Subsequently, the web was post-dried by zone heating while being transported with rolls. The obtained web was knurled and then wound up. The obtained cellulose acylate film had a thickness of 40 μm, an in-plane retardation of 1 nm at a wavelength of 550 nm, and a thickness direction retardation of 26 nm at a wavelength of 550 nm.

[0189] <Alkali Saponification Treatment> The cellulose acylate film obtained above was passed through a dielectric heating roll at a temperature of 60°C to raise the film surface temperature to 40°C, and then an alkaline solution having the composition shown below was applied to the band surface of the film using a bar coater in an amount of 14 ml / m ２ The coated film was then transported for 10 seconds under a steam-type far-infrared heater manufactured by Noritake Co., Ltd. that had been heated to 110° C. Subsequently, pure water was applied at a rate of 3 ml / m using the same bar coater. ２ Next, the film was washed with water using a fountain coater and then drained with an air knife three times, and then transported to a drying zone at 70° C. for 10 seconds to dry, thereby preparing an alkali-saponified cellulose acylate film.

[0190] --------------------------------------------------- Alkaline solution ----------------------------------- Potassium hydroxide 4.7 parts by mass Water 15.8 parts by mass Isopropanol 63.7 parts by mass Surfactant: C 14 H 29 O(CHCHO) 20 H 1.0 mass part Propylene glycol 14.8 mass parts

[0191] [Formation of Alignment Film] An alignment film coating solution having the following composition was continuously applied to the alkali-saponified surface of the cellulose acylate film using a #14 wire bar, and then dried with hot air at 60°C for 60 seconds and then with hot air at 100°C for 120 seconds.

[0192] Alignment film coating liquid -------------------------------- Polyvinyl alcohol (listed below) 10 parts by mass Water 371 parts by mass Methanol 119 parts by mass Glutaraldehyde (crosslinking agent) 0.5 parts by mass Citric acid ester (manufactured by Sankyo Chemical Co., Ltd.) 0.175 parts by mass ------------------------------------------------

[0193] Polyvinyl alcohol: Degree of polymerization: 300 (The value for each repeating unit represents the content (% by mass) of all repeating units.)

[0194] [Formation of First Optically Anisotropic Layer] The alignment film prepared above was continuously subjected to a rubbing treatment. At this time, the longitudinal direction of the long film was parallel to the conveying direction, and the angle between the longitudinal direction of the film (conveying direction) and the rotation axis of the rubbing roller was 76°. The longitudinal direction of the film (conveying direction) was set to 90°, and when observed from the film side, the width direction of the film was set as the reference (0°) and the clockwise direction was expressed as a positive value, so the rotation axis of the rubbing roller was at -14°. In other words, the position of the rotation axis of the rubbing roller was rotated 76° counterclockwise with the longitudinal direction of the film as the reference.

[0195] Onto the rubbed alignment film, a composition for forming an optically anisotropic layer (1a) containing a discotic liquid crystal compound of the following composition was applied using a Giesser coater to form a composition layer. The resulting composition layer was then heated with hot air at 110°C for 2 minutes to dry the solvent and ripen the alignment of the discotic liquid crystal compound, resulting in uniform alignment. Subsequently, the resulting composition layer was irradiated with 320 nm LED-UV (50 mJ / cm) from the air interface side at 60°C. ２ ), and an isomerization reaction was carried out. Thereafter, the mixture was irradiated with UV light (100 mJ / cm ) at 70°C. ２) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (1a). The thickness of the optically anisotropic layer (1a) was 1.7 μm, and the retardation at 550 nm was 168 nm. The value obtained by dividing the in-plane retardation at a wavelength of 550 nm by the thickness of the first optically anisotropic layer was 0.099. The angle of the in-plane slow axis of the optically anisotropic layer (1a) was parallel to the rotation axis of the rubbing roller, and when the width direction of the film was 0° (the longitudinal direction was 90° counterclockwise and −90° clockwise), the in-plane slow axis was −14° when viewed from the optically anisotropic layer (1a) side. The optically anisotropic layer (1a) corresponds to the first optically anisotropic layer.

[0196] Composition (1a) for forming optically anisotropic layer 1 100 parts by mass of discotic liquid crystal compound 1 described below 0.15 parts by mass of alignment film interface aligning agent 1 described below 0.1 part by mass of fluorine-containing compound A described below 0.05 part by mass of fluorine-containing compound B described below 0.21 parts by mass of fluorine-containing compound C described below 8.0 parts by mass of ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 6.0 parts by mass of photopolymerization initiator (APi-307, manufactured by Shenzhen UV ChemTech Ltd.) 200 parts by mass of methyl ethyl ketone

[0197] Discotic liquid crystal compound 1

[0198]

[0199] Alignment film interface alignment agent 1

[0200]

[0201] Fluorine-containing compound A (in the following formula, a and b represent the content (% by mass) of each repeating unit relative to all repeating units, a represents 90% by mass and b represents 10% by mass. The weight-average molecular weight was 15,000.)

[0202]

[0203] Fluorine-containing compound B (The numerical value for each repeating unit represents the content (% by mass) relative to all repeating units. The weight-average molecular weight was 12,500.)

[0204]

[0205] Fluorine-containing compound C (the numerical value for each repeating unit represents the content (% by mass) relative to all repeating units. The weight-average molecular weight was 12,500.)

[0206]

[0207] Photopolymerization initiator (APi-307, manufactured by Shenzhen UV ChemTech Ltd.)

[0208]

[0209] [Formation of Second Optically Anisotropic Layer] <Formation of Optically Anisotropic Layer (B)> An optically anisotropic layer-forming composition (1c) containing a rod-shaped liquid crystal compound having the following composition was applied onto the cellulose acylate film prepared above using a Giesser coater to form a composition layer. Thereafter, both ends of the film were held, and a cooling plate (9°C) was placed on the side of the film on which the coating film was formed so as to be 5 mm away from the film, and a heater (75°C) was placed on the side opposite the side on which the coating film was formed so as to be 5 mm away from the film, and the film was dried for 2 minutes. The film was then heated with warm air at 60°C for 1 minute, and irradiated with a 365 nm UV-LED at an irradiation dose of 100 mJ / cm while nitrogen purging was performed to maintain an atmosphere with an oxygen concentration of 100 ppm or less. ２ The precursor layer was then irradiated with UV light (ultra-high pressure mercury lamp; UL750; manufactured by HOYA) at room temperature through a wire grid polarizer at a dose of 7.9 mJ / cm. ２(wavelength: 313 nm) on the film, thereby forming a composition layer having alignment controllability on the surface. The film thickness of the formed composition layer was 0.6 μm. The in-plane retardation at a wavelength of 550 nm was 0 nm, and the retardation in the thickness direction at a wavelength of 550 nm was −80 nm. The average tilt angle of the long axis direction of the rod-like liquid crystal compound with respect to the film surface was 90°, and it was confirmed that the compound was aligned perpendicular to the film surface. The optically anisotropic layer (1c) corresponds to the optically anisotropic layer (B).

[0210] ------------------------------------------------ Composition for forming optically anisotropic layer (1c) -------------------------------------------------- Rod-like liquid crystal compound (A) shown below: 100 parts by mass Polymerizable monomer (A-400, manufactured by Shin-Nakamura Chemical Co., Ltd.) 4.0 parts by mass Polymerization initiator S-1 (oxime type) shown below: 5.0 parts by mass Photoacid generator D-1 shown below: 3.0 parts by mass Polymer M-1 shown below: 2.0 parts by mass Vertical alignment agent S01 shown below: 2.0 parts by mass Photoaligning polymer A-1 shown below: 42.3 parts by mass Methyl ethyl ketone 627.5 parts by mass Methyl isobutyl ketone

[0211] Rod-like liquid crystal compound (A) (hereinafter referred to as a mixture of compounds)

[0212]

[0213] Polymerization initiator S-1

[0214]

[0215] Photoacid generator D-1

[0216]

[0217] Polymer M-1 (The numerical value for each repeating unit represents the content (% by mass) relative to all repeating units. The weight-average molecular weight was 58,000.)

[0218]

[0219] Vertical alignment agent S01

[0220]

[0221] Photoalignable polymer A-1 (in the following formula, a, b, and c represent the content (% by mass) of each repeating unit relative to all repeating units, with a representing 40% by mass, b representing 25% by mass, and c representing 35% by mass. The weight-average molecular weight was 69,300.)

[0222]

[0223] <Formation of Optically Anisotropic Layer (A)> Next, on the prepared optically anisotropic layer (1c) was applied a composition for forming an optically anisotropic layer (1b) containing a rod-shaped liquid crystal compound having the following composition using a Giesser coater, and the mixture was heated with hot air at 60°C for 60 seconds. Subsequently, the obtained composition layer was irradiated with UV light (300 mJ / cm) at 80°C. ２ ) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (1b). The thickness of the optically anisotropic layer (1b) was 1.5 μm, the product Δnd of the birefringence and thickness at a wavelength of 550 nm was 164 nm, and the twist angle of the liquid crystal compound was 81°. When the width direction of the film was 0° (the longitudinal direction was 90°), the alignment axis angle of the liquid crystal compound when viewed from the optically anisotropic layer (1b) side was 14° on the air side and 95° on the side in contact with the optically anisotropic layer (1c). The alignment axis angle of the liquid crystal compound contained in the optically anisotropic layer was expressed as negative when clockwise (right-handed) and positive when counterclockwise (left-handed), with the width direction of the substrate being taken as the reference 0°, and the substrate being observed from the surface side of the optically anisotropic layer. The twist angle of the liquid crystal compound is expressed as a negative value when the orientation axis direction of the liquid crystal compound on the substrate side (rear side) is clockwise (right-handed) and a positive value when the orientation axis direction of the liquid crystal compound on the surface side (near side) is referenced to the orientation axis direction of the liquid crystal compound on the substrate side (rear side) when the orientation axis direction is clockwise (right-handed) and counterclockwise (left-handed) when the orientation axis direction is referenced to the orientation axis direction of the liquid crystal compound on the surface side (near side), when the orientation axis direction of the liquid crystal compound on the substrate side (rear side). The optically anisotropic layer (1b) corresponds to the optically anisotropic layer (A).

[0224] ------------------------------------------------ Composition (1b) for forming optically anisotropic layer ------------------------------------------------ Rod-shaped liquid crystal compound (A) above 70 parts by mass Rod-shaped liquid crystal compound (B) below 30 parts by mass Ethylene oxide modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 4 parts by mass Photopolymerization initiator (Irgacure 819, manufactured by BASF) 3 parts by mass Left-handed twisted chiral agent (L1) below 0.50 parts by mass Fluorine-containing compound D below 0.20 parts by mass Methyl isobutyl ketone 126 parts by mass Ethyl propionate 126 parts by mass

[0225] Rod-shaped liquid crystal compound (B)

[0226]

[0227] Left-Twisted Chiral Agent (L1) (Bu represents a butyl group)

[0228]

[0229] Fluorine-containing compound D (the content of the left-side repeating unit was 76 mass%, the content of the right-side repeating unit was 24 mass%, and the weight-average molecular weight was 27,500).

[0230] By the above procedure, an optically anisotropic layer (1b-1c) was prepared in which an optically anisotropic layer (1c) and an optically anisotropic layer (1b) were directly laminated on a long cellulose acylate film. When the surface of the optically anisotropic layer (1c) in contact with the optically anisotropic layer (1b) was examined, it was confirmed that a photo-alignable polymer was present. The optically anisotropic layer (1b-1c) corresponds to the optically anisotropic layer (AB).

[0231] [Preparation of Polarizing Plate] <Preparation of Linear Polarizer> The support surface of a cellulose triacetate film TJ25 (manufactured by Fujifilm Corporation; thickness: 25 μm) was subjected to alkaline saponification treatment. Specifically, the support was immersed in a 1.5 N sodium hydroxide aqueous solution at 55°C for 2 minutes, then washed in a water bath at room temperature, and further neutralized with 0.1 N sulfuric acid at 30°C. After neutralization, the support was washed in a water bath at room temperature and further dried with hot air at 100°C to obtain a polarizer protective film. A roll-shaped polyvinyl alcohol (PVA) film with a thickness of 60 μm was continuously stretched in the longitudinal direction in an iodine aqueous solution and dried to obtain a linear polarizer with a thickness of 13 μm. The luminous efficiency-corrected single transmittance of the polarizer was 43%. At this time, the absorption axis direction and the longitudinal direction of the polarizer were aligned. A linear polarizer was prepared by bonding the polarizer protective film to one surface of the polarizer using the PVA adhesive described below.

[0232] <Preparation of PVA adhesive> 100 parts by mass of a polyvinyl alcohol resin having acetoacetyl groups (average degree of polymerization: 1200, degree of saponification: 98.5 mol%, degree of acetoacetylation: 5 mol%) and 20 parts by mass of methylol melamine were dissolved in pure water at a temperature of 30°C to prepare an aqueous solution with a solids concentration adjusted to 3.7% by mass, thereby preparing a PVA adhesive.

[0233] <Preparation of Optical Film> The surface side of the optically anisotropic layer (1a) formed on the long cellulose acylate film prepared above was subjected to a corona discharge treatment. The corona discharge treatment conditions were an output intensity of 2.5 kW, a line speed of 18 m / min, an electrode length of 1.4 m, and a gap distance of 2 mm. The corona-treated surface was coated with the following ultraviolet-curable adhesive (1d) to a film thickness of 1.5 μm. The corona discharge treatment was also performed on the surface side of the optically anisotropic layer (1b) of the optically anisotropic layer (1b-1c) formed on the long cellulose acylate film prepared above. The corona discharge treatment conditions were an output intensity of 5.0 kW, a line speed of 18 m / min, an electrode length of 1.4 m, and a gap distance of 2 mm. The corona-treated surface was coated with the following adhesive (1d) to a film thickness of 1.0 μm. The adhesive (1d) coated on the optically anisotropic layer (1a) and the adhesive (1d) coated on the optically anisotropic layer (1b) were laminated together, heated to 50°C using an IR heater, and UV light was irradiated from both sides of the cellulose acylate film of the laminate to cure the adhesive (1d), followed by thermal drying at 70°C for 3 minutes. The thickness of the cured adhesive layer (1d) was 2.0 μm as determined by SEM observation of a cut cross section. This resulted in an optical film (1a-1b-1c) having a layer structure of optically anisotropic layer (1a)-adhesive layer (1d)-optically anisotropic layer (1b-1c). In the optical film (1a-1b-1c), the optically anisotropic layer (1b) was disposed on the adhesive layer (1d) side. The optical films (1a-1b-1c) had an in-plane retardation of 141 nm at a wavelength of 550 nm.

[0234] ------------------------------------------------------------------ Adhesive (1d) ------------------------------------------------------------------ Acryloylmorpholine (manufactured by Kojinsha) 15 parts by mass N-hydroxyacrylamide (manufactured by Kojinsha) 15 parts by mass Tripropylene glycol diacrylate (Aronix M-220, manufactured by Toagosei Co., Ltd.) 10 parts by mass OGSOL EA-F5710 (manufactured by Osaka Gas Chemicals Co., Ltd.) 60 parts by mass Photopolymerization initiator (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.) 1.5 parts by mass ------------------------------------------------------------------

[0235] <Preparation of Polarizing Plate> A corona discharge treatment was performed on the exposed surface of the optical film (1a-1b-1c), which was the surface of the optically anisotropic layer (1a) that had been in contact with the cellulose acylate film. The corona discharge treatment conditions were an output intensity of 2.5 kW, a line speed of 18 m / min, an electrode length of 1.4 m, and a gap distance of 2 mm. The corona-treated surface was coated with the following ultraviolet-curable adhesive (2d) to a film thickness of 1.5 μm. The surface of the long linear polarizer prepared above opposite the polarizer protective film and the surface of the optical film (1a-1b-1c) coated with the adhesive (2d) were bonded together to obtain a laminate of linear polarizer-adhesive layer (2d)-optically anisotropic layer (1a)-adhesive layer (1d)-optically anisotropic layer (1b-1c). Subsequently, the cellulose acylate film on the optically anisotropic layer (1b-1c) side was peeled off to expose the surface of the optically anisotropic layer (1b-1c) that had been in contact with the cellulose acylate film. This produced a polarizing plate (P1) comprising the optical film (1a-1b-1c) and a linear polarizer. The polarizing plate (P1) had a polarizer protective film, a polarizer, an adhesive layer (2d), an optically anisotropic layer (1a), an adhesive layer (1d), an optically anisotropic layer (1b), and an optically anisotropic layer (1c) laminated in this order, and corresponds to the polarizing plate of Aspect 1. The angle formed between the absorption axis of the polarizer and the in-plane slow axis of the optically anisotropic layer (1a) was −76°. Furthermore, the alignment axis angle of the liquid crystal compound on the optically anisotropic layer (1b) side of the optically anisotropic layer (1a) was −14°, with the width direction being taken as the reference angle of 0°, which coincided with the in-plane slow axis direction of the optically anisotropic layer (1a).

[0236] ---------------------------------------------------------------- Adhesive (2d) ---------------------------------------------------------------- Acryloylmorpholine (manufactured by Kojinsha) 20 parts by mass N-hydroxyacrylamide (manufactured by Kojinsha) 20 parts by mass Tripropylene glycol diacrylate (Aronix M-220, manufactured by Toagosei Co., Ltd.) 20 parts by mass OGSOL EA-F5710 (manufactured by Osaka Gas Chemicals Co., Ltd.) 40 parts by mass Photopolymerization initiator (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.) 1.5 parts by mass ----------------------------------------------------------------

[0237] [Example 2] Polarizing plate P2 was produced in the same manner as in Example 1, except that the procedures of the above-mentioned [Formation of first optically anisotropic layer] and <Formation of optically anisotropic layer (A)> were changed as follows, and the procedure of the above-mentioned <Preparation of optical film> was changed as follows.

[0238] [Formation of First Optically Anisotropic Layer] A composition for forming an optically anisotropic layer (2a) containing a discotic liquid crystal compound of the following composition was applied onto the rubbed alignment film using a Giesser coater to form a composition layer. Thereafter, the obtained composition layer was heated with hot air at 110°C for 2 minutes to dry the solvent and ripen the alignment of the discotic liquid crystal compound, thereby achieving uniform alignment. Subsequently, the obtained composition layer was irradiated with UV (100 mJ / cm) at 70°C. ２ ) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (2a). The thickness of the optically anisotropic layer (2a) was 1.5 μm, and the retardation at 550 nm was 168 nm. The value obtained by dividing the in-plane retardation at a wavelength of 550 nm by the thickness of the first optically anisotropic layer was 0.110. The angle of the in-plane slow axis of the optically anisotropic layer (2a) was parallel to the rotation axis of the rubbing roller, and when the width direction of the film was 0° (the longitudinal direction was 90° counterclockwise and −90° clockwise), the in-plane slow axis was −14° when viewed from the optically anisotropic layer (2a) side. The optically anisotropic layer (2a) corresponds to the first optically anisotropic layer.

[0239] ------------------------------------------------ Composition for forming optically anisotropic layer (2a) -------------------------------------------------- 80 parts by mass of discotic liquid crystal compound 2 described below 20 parts by mass of discotic liquid crystal compound 3 described below 0.12 parts by mass of the alignment film interface aligning agent 1 described above 0.1 part by mass of the fluorine-containing compound A described above 0.05 part by mass of the fluorine-containing compound B described above 0.21 parts by mass of the fluorine-containing compound C described above 6.0 parts by mass of ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) Photopolymerization initiator (APi-307, manufactured by Shenzhen UV ChemTech Ltd.) 6.0 parts by mass Methyl ethyl ketone 200 parts by mass --------------------------------------------------

[0240] Discotic liquid crystal compound 2

[0241]

[0242] Discotic liquid crystal compound 3

[0243]

[0244] <Formation of Optically Anisotropic Layer (A)> On the optically anisotropic layer (1c) prepared above, a composition for forming an optically anisotropic layer (2b) containing a rod-shaped liquid crystal compound having the following composition was applied using a Giesser coater, and the layer was heated with hot air at 60°C for 60 seconds. At 60°C, the layer was irradiated with 320 nm LED-UV (40 mJ / cm) from the air interface side. ２ ), and an isomerization reaction was carried out. Thereafter, the obtained composition layer was irradiated with UV (300 mJ / cm ) at 80°C. ２) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (2b). The thickness of the optically anisotropic layer (2b) was 1.6 μm, Δnd at a wavelength of 550 nm was 164 nm, and the twist angle of the liquid crystal compound was 81°. When the width direction of the film was set to 0° (the longitudinal direction was 90°), the alignment axis angle of the liquid crystal compound when viewed from the optically anisotropic layer (2b) side was 14° on the air side and 95° on the side in contact with the optically anisotropic layer (1c). The alignment axis angle of the liquid crystal compound contained in the optically anisotropic layer was expressed as negative when clockwise (right-handed) and positive when counterclockwise (left-handed), with the width direction of the substrate set to 0° as the reference. The twist angle of the liquid crystal compound is expressed by observing the substrate from the surface side of the optically anisotropic layer, with the orientation axis direction of the liquid crystal compound on the surface side (front side) as the reference, and when the orientation axis direction of the liquid crystal compound on the substrate side (rear side) is clockwise (right-handed), it is negative, and when it is counterclockwise (left-handed), it is positive.

[0245] ------------------------------------------------ Composition for forming optically anisotropic layer (2b)------------------------------------------------ Rod-shaped liquid crystal compound (A) above: 60 parts by mass Rod-shaped liquid crystal compound (C) below: 40 parts by mass Ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 5 parts by mass Photopolymerization initiator (Irgacure 819, manufactured by BASF) 3 parts by mass Left-handed twisted chiral agent (L1) above: 0.70 parts by mass Fluorine-containing compound D above: 0.18 parts by mass Methyl isobutyl ketone 126 parts by mass Ethyl propionate 126 parts by mass

[0246] Rod-shaped liquid crystal compound (C)

[0247]

[0248] <Preparation of Optical Film> The surface side of the optically anisotropic layer (2a) formed on the long cellulose acylate film prepared above was subjected to a corona discharge treatment. The corona discharge treatment conditions were an output intensity of 2.5 kW, a line speed of 18 m / min, an electrode length of 1.4 m, and a gap distance of 2 mm. The corona-treated surface was coated with adhesive (1d) to a thickness of 1.5 μm. The corona discharge treatment was also performed on the surface side of the optically anisotropic layer (2b) of the optically anisotropic layer (1c-2b) formed on the long cellulose acylate film prepared above. The corona discharge treatment conditions were an output intensity of 5.0 kW, a line speed of 18 m / min, an electrode length of 1.4 m, and a gap distance of 2 mm. The corona-treated surface was coated with adhesive (1d) to a thickness of 1.0 μm. The adhesive (1d) coated on the optically anisotropic layer (2a) and the adhesive (1d) coated on the optically anisotropic layer (2b) were laminated together, heated to 50°C using an IR heater, and irradiated with UV light from both sides of the cellulose acylate film of the laminate to cure the adhesive (1d). The laminate was then thermally dried at 70°C for 3 minutes. The thickness of the cured adhesive layer (1d) was 2.0 μm as determined by SEM observation of a cut cross section. This resulted in an optical film (2a-2b-1c) having a layer structure of optically anisotropic layer (2a)-adhesive layer (1d)-optically anisotropic layer (2b-1c). In the optical film (2a-2b-1c), the optically anisotropic layer (2b) was disposed on the adhesive layer (1d) side. The in-plane retardation of the optical film (2a-2b-1c) at a wavelength of 550 nm was 141 nm.

[0249] Example 3 A polarizing plate P3 was prepared in the same manner as in Example 2, except that the procedure for <Formation of Optically Anisotropic Layer (A)> was changed as follows.

[0250] [Formation of Optically Anisotropic Layer (A)] Next, on the optically anisotropic layer (1c) prepared above, a composition for forming an optically anisotropic layer (3b) containing a rod-shaped liquid crystal compound having the following composition was applied using a Giesser coater, and heated with hot air at 60°C for 60 seconds. Subsequently, the obtained composition layer was irradiated with UV light (300 mJ / cm) at 70°C. ２) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (3b). The thickness of the optically anisotropic layer (3b) was 1.6 μm, Δnd at a wavelength of 550 nm was 164 nm, and the twist angle of the liquid crystal compound was 81°. When the width direction of the film was set to 0° (the longitudinal direction was 90°), the alignment axis angle of the liquid crystal compound when viewed from the optically anisotropic layer (3b) side was 14° on the air side and 95° on the side in contact with the optically anisotropic layer (1c). The alignment axis angle of the liquid crystal compound contained in the optically anisotropic layer was expressed as negative when clockwise (right-handed) and positive when counterclockwise (left-handed), with the width direction of the substrate set to 0° as the reference. The twist angle of the liquid crystal compound is expressed by observing the substrate from the surface side of the optically anisotropic layer, with the orientation axis direction of the liquid crystal compound on the surface side (front side) as the reference, and when the orientation axis direction of the liquid crystal compound on the substrate side (rear side) is clockwise (right-handed), it is negative, and when it is counterclockwise (left-handed), it is positive.

[0251] ------------------------------------------------ Composition for forming optically anisotropic layer (3b)------------------------------------------------ Rod-shaped liquid crystal compound (A) above: 70 parts by mass Rod-shaped liquid crystal compound (B) above: 30 parts by mass Ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 5 parts by mass Photopolymerization initiator (Irgacure 819, manufactured by BASF) 3 parts by mass Left-handed twisted chiral agent (L1) above: 0.60 parts by mass Fluorine-containing compound D above: 0.18 parts by mass Fluorine-containing compound E below: 0.02 parts by mass Methyl isobutyl ketone 126 parts by mass Ethyl propionate 126 parts by mass

[0252] Fluorine-containing compound E (the content of the left-side repeating unit was 50% by mass, the content of the right-side repeating unit was 50% by mass, and the weight-average molecular weight was 24,700)

[0253]

[0254] Example 4 A polarizing plate P4 was produced in the same manner as in Example 1, except that in the above-mentioned <Production of Optical Film>, the optically anisotropic layer (1b) was changed to the optically anisotropic layer (2b).

[0255] [Example 5] Polarizing plate P5 was prepared in the same manner as in Example 1, except that the procedure for [Formation of first optically anisotropic layer] described above was changed as follows, and the procedures for <Preparation of optical film> and <Preparation of polarizing plate> described above were changed as follows.

[0256] [Formation of First Optically Anisotropic Layer] A composition for forming an optically anisotropic layer (2a) containing the discotic liquid crystal compound of the above composition was applied onto the rubbed alignment film using a Giesser coater to form a composition layer. Thereafter, the obtained composition layer was heated with hot air at 110°C for 2 minutes to dry the solvent and ripen the alignment of the discotic liquid crystal compound, thereby achieving uniform alignment. The layer was then irradiated with 320 nm LED-UV (50 mJ / cm) from the air interface side at 60°C. ２ Subsequently, the obtained composition layer was irradiated with UV (100 mJ / cm ) at 70°C. ２ ) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (3a). The thickness of the optically anisotropic layer (3a) was 1.5 μm, and the retardation at 550 nm was 168 nm. The value obtained by dividing the in-plane retardation at a wavelength of 550 nm by the thickness of the first optically anisotropic layer was 0.110. The angle of the in-plane slow axis of the optically anisotropic layer (3a) was parallel to the rotation axis of the rubbing roller, and when the width direction of the film was 0° (the longitudinal direction was 90° counterclockwise and −90° clockwise), the in-plane slow axis was +14° when viewed from the optically anisotropic layer (3a) side. The optically anisotropic layer (3a) corresponds to the first optically anisotropic layer.

[0257] <Preparation of Optical Film and Preparation of Polarizing Plate> The surface side of the optically anisotropic layer (3a) formed on the long cellulose acylate film prepared above was subjected to a corona discharge treatment. The corona discharge treatment conditions were an output intensity of 2.5 kW, a line speed of 18 m / min, an electrode length of 1.4 m, and a gap distance of 2 mm. The corona-treated surface was coated with adhesive (2d) to a film thickness of 1.5 μm. The surface of the long linear polarizer prepared above opposite the polarizer protective film and the surface of the optically anisotropic layer (3a) coated with adhesive (2d) were bonded together to obtain a laminate of linear polarizer, adhesive layer (2d), and optically anisotropic layer (3a). Subsequently, the surface side of the optically anisotropic layer (1b-1c) formed on the long cellulose acylate film prepared above, on the 1b side, was subjected to a corona discharge treatment. The corona discharge treatment conditions were an output intensity of 2.8 kW, a line speed of 18 m / min, an electrode length of 1.4 m, and a gap distance of 2 mm. An adhesive (1d) was applied to the corona-treated surface to a thickness of 1.5 μm. The cellulose acylate film on the 3a side of the linear polarizer-adhesive layer (2d)-optically anisotropic layer (3a) laminate was peeled off, and the surface that had been in contact with the cellulose acylate film was subjected to a corona discharge treatment. The corona discharge treatment conditions were an output intensity of 2.0 kW, a line speed of 18 m / min, an electrode length of 1.4 m, and a gap distance of 2 mm. The corona-treated surface of the linear polarizer-adhesive layer (2d)-optically anisotropic layer (3a) laminate that had been in contact with the cellulose acylate film was bonded to the adhesive (1d) applied to the 1b side of the optically anisotropic layer (1b-1c) formed on the cellulose acylate film. This produced a polarizing plate P5 containing the optical film (3a-1b-1c) and a linear polarizer. The polarizing plate P5 had a polarizer protective film, a polarizer, an adhesive layer (2d), an optically anisotropic layer (3a), an adhesive layer (1d), an optically anisotropic layer (1b), and an optically anisotropic layer (1c) laminated in this order, and corresponds to the polarizing plate of embodiment 1. The angle formed by the absorption axis of the polarizer and the in-plane slow axis of the optically anisotropic layer (3a) was −76°. Furthermore, with the width direction taken as the reference angle of 0°, the alignment axis angle of the liquid crystal compound on the optically anisotropic layer (3a) side of the optically anisotropic layer (1b) was −14°, which coincided with the in-plane slow axis direction of the optically anisotropic layer (3a).

[0258] Example 6 A polarizing plate P6 was prepared in the same manner as in Example 1, except that the procedure for forming the first optically anisotropic layer was changed as follows.

[0259] [Formation of First Optically Anisotropic Layer] A composition for forming an optically anisotropic layer (4a) containing a discotic liquid crystal compound of the following composition was applied onto the rubbed alignment film using a Giesser coater to form a composition layer. Thereafter, the obtained composition layer was heated with hot air at 100°C for 2 minutes to dry the solvent and ripen the alignment of the discotic liquid crystal compound, thereby achieving uniform alignment. Subsequently, the obtained composition layer was irradiated with 320 nm LED-UV (30 mJ / cm) from the air interface side at 60°C. ２ ), and an isomerization reaction was carried out. Thereafter, the mixture was irradiated with UV light (100 mJ / cm ) at 70°C. ２ ) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (4a). The thickness of the optically anisotropic layer (4a) was 1.5 μm, and the retardation at 550 nm was 168 nm. The value obtained by dividing the in-plane retardation at a wavelength of 550 nm by the thickness of the first optically anisotropic layer was 0.113. The angle of the in-plane slow axis of the optically anisotropic layer (4a) was parallel to the rotation axis of the rubbing roller, and when the width direction of the film was 0° (the longitudinal direction was 90° counterclockwise and −90° clockwise), the in-plane slow axis was −14° when viewed from the optically anisotropic layer (4a) side. The optically anisotropic layer (4a) corresponds to the first optically anisotropic layer.

[0260] ------------------------------------------------ Optically anisotropic layer-forming composition (4a)---------------------------------------------------------------- 20 parts by mass of the above discotic liquid crystal compound 1------------------------------------------------ 60 parts by mass of the above discotic liquid crystal compound 2------------------------------------------------ 20 parts by mass of the above discotic liquid crystal compound 3------------------------------------------------ 0.15 parts by mass of the above alignment film interface aligning agent 1------------------------------------------------ 0.1 part by mass of the above fluorine-containing compound A------------------------------------------------ 0.05 parts by mass of the above fluorine-containing compound B------------------------------------------------ 0.21 parts by mass of the above fluorine-containing compound C------------------------------------------------ 4.0 parts by mass of ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 6.0 parts by mass of photopolymerization initiator (APi-307, manufactured by Shenzhen UV ChemTech Ltd.) 200 parts by mass of methyl ethyl ketone----------------------------------------------------------------

[0261] Example 7 A polarizing plate P7 was prepared in the same manner as in Example 1, except that the procedure for forming the first optically anisotropic layer was changed as follows.

[0262] [Formation of First Optically Anisotropic Layer] A composition for forming an optically anisotropic layer (5a) containing a discotic liquid crystal compound of the following composition was applied onto the rubbed alignment film using a Giesser coater to form a composition layer. Thereafter, the obtained composition layer was heated with hot air at 90°C for 2 minutes to dry the solvent and ripen the alignment of the discotic liquid crystal compound, thereby achieving uniform alignment. Subsequently, the obtained composition layer was irradiated with 320 nm LED-UV (70 mJ / cm) from the air interface side at 60°C. ２ ), and an isomerization reaction was carried out. Thereafter, the mixture was irradiated with UV light (100 mJ / cm ) at 60°C. ２) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (5a). The thickness of the optically anisotropic layer (5a) was 1.5 μm, and the retardation at 550 nm was 168 nm. The value obtained by dividing the in-plane retardation at a wavelength of 550 nm by the thickness of the first optically anisotropic layer was 0.109. The angle of the in-plane slow axis of the optically anisotropic layer (5a) was parallel to the rotation axis of the rubbing roller, and when the width direction of the film was 0° (the longitudinal direction was 90° counterclockwise and −90° clockwise), the in-plane slow axis was −14° when viewed from the optically anisotropic layer (5a) side. The optically anisotropic layer (5a) corresponds to the first optically anisotropic layer.

[0263] ------------------------------------------------ Optically anisotropic layer-forming composition (5a)---------------------------------------------------------------- 40 parts by mass of the above discotic liquid crystal compound 1---------------------------------------------------------------- 40 parts by mass of the above discotic liquid crystal compound 2------------------------------------------------ 20 parts by mass of the above discotic liquid crystal compound 3------------------------------------------------ 0.15 parts by mass of the above alignment film interface aligning agent 1------------------------------------------------ 0.1 part by mass of the above fluorine-containing compound A------------------------------------------------ 0.05 parts by mass of the above fluorine-containing compound B------------------------------------------------ 0.21 parts by mass of the above fluorine-containing compound C------------------------------------------------ 3.0 parts by mass of ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 6.0 parts by mass of photopolymerization initiator (APi-307, manufactured by Shenzhen UV ChemTech Ltd.) 200 parts by mass of methyl ethyl ketone----------------------------------------------------------------

[0264] Example 8 A polarizing plate P8 was prepared in the same manner as in Example 1, except that the procedure for forming the first optically anisotropic layer was changed as follows.

[0265] [Formation of First Optically Anisotropic Layer] A composition for forming an optically anisotropic layer (6a) containing a discotic liquid crystal compound of the following composition was applied onto the rubbed alignment film using a Giesser coater to form a composition layer. Thereafter, the obtained composition layer was heated with hot air at 110°C for 2 minutes to dry the solvent and ripen the alignment of the discotic liquid crystal compound, thereby achieving uniform alignment. Subsequently, the obtained composition layer was irradiated with 320 nm LED-UV (70 mJ / cm) from the air interface side at 60°C. ２ ), and an isomerization reaction was carried out. Thereafter, the mixture was irradiated with UV light (100 mJ / cm ) at 70°C. ２ ) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (6a). The thickness of the optically anisotropic layer (6a) was 1.6 μm, and the retardation at 550 nm was 168 nm. The value obtained by dividing the in-plane retardation at a wavelength of 550 nm by the thickness of the first optically anisotropic layer was 0.106. The angle of the in-plane slow axis of the optically anisotropic layer (6a) was parallel to the rotation axis of the rubbing roller, and when the width direction of the film was 0° (the longitudinal direction was 90° counterclockwise and −90° clockwise), the in-plane slow axis was −14° when viewed from the optically anisotropic layer (6a) side. The optically anisotropic layer (6a) corresponds to the first optically anisotropic layer.

[0266] ------------------------------------------------ Optically anisotropic layer-forming composition (6a)------------------------------------------------ 80 parts by mass of the above discotic liquid crystal compound 1------------------------------------------------ 20 parts by mass of the above discotic liquid crystal compound 2------------------------------------------------ 0.15 parts by mass of the above alignment film interface aligning agent 1------------------------------------------------ 0.1 part by mass of the above fluorine-containing compound A------------------------------------------------ 0.05 parts by mass of the above fluorine-containing compound B------------------------------------------------ 0.21 parts by mass of the above fluorine-containing compound C------------------------------------------------ 5.0 parts by mass of ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 6.0 parts by mass of photopolymerization initiator (APi-307, manufactured by Shenzhen UV ChemTech Ltd.) 200 parts by mass of methyl ethyl ketone----------------------------------------------------------------

[0267] Example 9 A polarizing plate P9 was produced in the same manner as in Example 2, except that the procedure of the above-mentioned <Method of forming optically anisotropic layer (A)> was changed as follows.

[0268] <Method of forming optically anisotropic layer (A)> On the optically anisotropic layer (1c) prepared above, a composition for forming an optically anisotropic layer (4b) containing a rod-shaped liquid crystal compound having the following composition was applied using a Giesser coater, and the layer was heated with hot air at 60°C for 60 seconds. At 60°C, the layer was irradiated with 320 nm LED-UV (50 mJ / cm) from the air interface side. ２ ), and an isomerization reaction was carried out. Thereafter, the obtained composition layer was irradiated with UV (300 mJ / cm ) at 80°C. ２) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (4b). The thickness of the optically anisotropic layer (4b) was 1.5 μm, Δnd at a wavelength of 550 nm was 164 nm, and the twist angle of the liquid crystal compound was 81°. When the width direction of the film was set to 0° (the longitudinal direction was 90°), the alignment axis angle of the liquid crystal compound when viewed from the optically anisotropic layer (4b) side was 14° on the air side and 95° on the side in contact with the optically anisotropic layer (1c). The alignment axis angle of the liquid crystal compound contained in the optically anisotropic layer was expressed as negative when clockwise (right-handed) and positive when counterclockwise (left-handed), with the width direction of the substrate set to 0° as the reference. The twist angle of the liquid crystal compound is expressed by observing the substrate from the surface side of the optically anisotropic layer, with the orientation axis direction of the liquid crystal compound on the surface side (front side) as the reference, and when the orientation axis direction of the liquid crystal compound on the substrate side (rear side) is clockwise (right-handed), it is negative, and when it is counterclockwise (left-handed), it is positive.

[0269] ------------------------------------------------ Optically anisotropic layer forming composition (4b)---------------------------------------------------------------- Rod-shaped liquid crystal compound (A) 90 parts by mass Rod-shaped liquid crystal compound (C) 10 parts by mass Ethylene oxide modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 4 parts by mass Photopolymerization initiator (Irgacure 819, manufactured by BASF) 3 parts by mass Left-handed twisted chiral agent (L1) 0.70 parts by mass Fluorine-containing compound D 0.18 parts by mass Methyl isobutyl ketone 126 parts by mass Ethyl propionate 126 parts by mass

[0270] Example 10 A polarizing plate P10 was produced in the same manner as in Example 2, except that the procedure of the above-mentioned <Method of forming optically anisotropic layer (A)> was changed as follows.

[0271] <Method of forming optically anisotropic layer (A)> On the optically anisotropic layer (1c) prepared above, a composition for forming an optically anisotropic layer (5b) containing a rod-shaped liquid crystal compound having the following composition was applied using a Giesser coater, and the layer was heated with hot air at 60°C for 60 seconds. At 60°C, the layer was irradiated with 320 nm LED-UV (40 mJ / cm) from the air interface side. ２ ), and an isomerization reaction was carried out. Thereafter, the obtained composition layer was irradiated with UV (300 mJ / cm ) at 80°C. ２ ) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (5b). The thickness of the optically anisotropic layer (5b) was 1.6 μm, Δnd at a wavelength of 550 nm was 164 nm, and the twist angle of the liquid crystal compound was 81°. When the width direction of the film was set to 0° (the longitudinal direction was 90°), the alignment axis angle of the liquid crystal compound when viewed from the optically anisotropic layer (5b) side was 14° on the air side and 95° on the side in contact with the optically anisotropic layer (1c). The alignment axis angle of the liquid crystal compound contained in the optically anisotropic layer was expressed as negative when clockwise (right-handed) and positive when counterclockwise (left-handed), with the width direction of the substrate set to 0° as the reference. The twist angle of the liquid crystal compound is expressed by observing the substrate from the surface side of the optically anisotropic layer, with the orientation axis direction of the liquid crystal compound on the surface side (front side) as the reference, and when the orientation axis direction of the liquid crystal compound on the substrate side (rear side) is clockwise (right-handed), it is negative, and when it is counterclockwise (left-handed), it is positive.

[0272] ------------------------------------------------ Composition for forming optically anisotropic layer (5b)------------------------------------------------ Rod-shaped liquid crystal compound (A) above: 80 parts by mass Rod-shaped liquid crystal compound (C) above: 20 parts by mass Ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 4 parts by mass Photopolymerization initiator (Irgacure 819, manufactured by BASF) 3 parts by mass Left-handed twisted chiral agent (L1) above: 0.70 parts by mass Fluorine-containing compound D above: 0.18 parts by mass Methyl isobutyl ketone 126 parts by mass Ethyl propionate 126 parts by mass

[0273] Example 11 A polarizing plate was produced in the same manner as in Example 1, except that an acrylic pressure-sensitive adhesive (3d) having an average refractive index of 1.57 was used instead of the adhesive (1d).

[0274] Example 12 A polarizing plate was produced in the same manner as in Example 1, except that an epoxy cross-linking adhesive (4d) having an average refractive index of 1.57 was used instead of the adhesive (1d).

[0275] Example 13 A polarizing plate was produced in the same manner as in Example 1, except that in the above-mentioned <Formation of Optical Film>, the adhesive (1d) was changed to the adhesive (2d).

[0276] Example 14 A polarizing plate was produced in the same manner as in Example 1, except that in the above-mentioned <Formation of Optical Film>, the adhesive (1d) was changed to the following ultraviolet-curable adhesive (4d).

[0277] ---------------------------------------------------------------- Adhesive (4d) ---------------------------------------------------------------- Acryloylmorpholine (manufactured by Kojinsha) 40 parts by mass N-hydroxyacrylamide (manufactured by Kojinsha) 30 parts by mass Tripropylene glycol diacrylate (Aronix M-220, manufactured by Toagosei Co., Ltd.) 20 parts by mass OGSOL EA-F5710 (manufactured by Osaka Gas Chemicals Co., Ltd.) 10 parts by mass Photopolymerization initiator (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.) 1.5 parts by mass ----------------------------------------------------------------

[0278] Example 15 A polarizing plate was produced in the same manner as in Example 1, except that in the above-mentioned <Formation of Optical Film>, the adhesive (1d) was changed to the following ultraviolet-curable adhesive (5d).

[0279] ---------------------------------------------------------------- Adhesive (5d) ---------------------------------------------------------------- Acryloylmorpholine (manufactured by Kojinsha) 10 parts by mass N-hydroxyacrylamide (manufactured by Kojinsha) 5 parts by mass Tripropylene glycol diacrylate (Aronix M-220, manufactured by Toagosei Co., Ltd.) 10 parts by mass OGSOL EA-F5710 (manufactured by Osaka Gas Chemicals Co., Ltd.) 75 parts by mass Photopolymerization initiator (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.) 1.5 parts by mass ----------------------------------------------------------------

[0280] Example 16 A polarizing plate P16 was produced in the same manner as in Example 1, except that the above-mentioned <Formation of Optical Film> step was changed as follows.

[0281] The surface side of the optically anisotropic layer (1a) formed on the long cellulose acylate film prepared above was subjected to a corona discharge treatment. The corona discharge treatment conditions were an output intensity of 2.5 kW, a line speed of 18 m / min, an electrode length of 1.4 m, and a gap distance of 2 mm. The corona-treated surface was coated with the ultraviolet-curable adhesive (1d) to a thickness of 5.5 μm. The corona discharge treatment was also performed on the surface side of the optically anisotropic layer (1b) of the optically anisotropic layer (1c-1b) formed on the long cellulose acylate film prepared above. The corona discharge treatment conditions were an output intensity of 5.0 kW, a line speed of 18 m / min, an electrode length of 1.4 m, and a gap distance of 2 mm. The corona-treated surface was coated with the adhesive (1d) to a thickness of 6.0 μm. The adhesive (1d) coated on the optically anisotropic layer (1a) and the adhesive (1d) coated on the optically anisotropic layer (1b) were laminated together, heated to 50°C using an IR heater, and UV light was irradiated from both sides of the cellulose acylate film of the laminate to cure the adhesive (1d), followed by thermal drying at 70°C for 3 minutes. The film thickness after curing was 11.0 μm as determined by SEM observation of a cut cross section. This resulted in an optical film (1a-1b-1c) having a layer structure of optically anisotropic layer (1a)-adhesive layer (1d)-optically anisotropic layer (1b-1c). In the optical film (1a-1b-1c), the optically anisotropic layer (1b) was disposed on the adhesive layer (1d) side of the optically anisotropic layer (1b-1c). The optical films (1a-1b-1c) had an in-plane retardation of 141 nm at a wavelength of 550 nm.

[0282] Examples 17 to 19 Polarizing plates were produced in the same manner as in Example 1, except that in the above-mentioned <Production of Optical Film>, the component ratio of the adhesive (1d) and the lamination conditions were adjusted to form an adhesive layer having the thickness and thickness unevenness σ shown in the table below.

[0283] [Example 20] [Formation of First Optically Anisotropic Layer] In the same manner as in the above-described optically anisotropic layer (1a), an alignment film coated on a cellulose acylate film was continuously subjected to a rubbing treatment. At this time, the longitudinal direction of the long film was parallel to the conveying direction, and the angle between the longitudinal direction of the film (conveying direction) and the rotation axis of the rubbing roller was 73°. The longitudinal direction (conveying direction) of the film was set to 90°, and when observed from the film side, the width direction of the film was used as the reference (0°) and the clockwise direction was expressed as a positive value, so the rotation axis of the rubbing roller was at -17°. In other words, the position of the rotation axis of the rubbing roller was rotated 73° counterclockwise with the longitudinal direction of the film as the reference.

[0284] Onto the alignment film that had been subjected to the rubbed treatment, a composition for forming an optically anisotropic layer (7a) containing a discotic liquid crystal compound of the following composition was applied using a Giesser coater to form a composition layer. The resulting composition layer was then heated with hot air at 110°C for 2 minutes to dry the solvent and ripen the alignment of the discotic liquid crystal compound. The layer was then irradiated with 320 nm LED-UV (60 mJ / cm) from the air interface side at 60°C. ２ ), and an isomerization reaction was carried out. Thereafter, the obtained composition layer was irradiated with UV (70 mJ / cm ) at 80°C. ２ ) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (7a). The thickness of the optically anisotropic layer (7a) was 2.3 μm. The in-plane retardation at 550 nm was 236 nm. The angle of the in-plane slow axis of the optically anisotropic layer (7a) was parallel to the rotation axis of the rubbing roller, and when the width direction of the film was 0° (the longitudinal direction was 90° counterclockwise and −90° clockwise), the in-plane slow axis was −17° when viewed from the optically anisotropic layer (7a) side. The optically anisotropic layer (7a) corresponds to the first optically anisotropic layer.

[0285] Optically anisotropic layer-forming composition (7a) ---------------------------------------------------------------- Discotic liquid crystal compound 1 100 parts by mass Alignment film interface aligning agent 1 0.10 parts by mass Fluorine-containing compound A 0.1 part by mass Fluorine-containing compound B 0.05 part by mass Fluorine-containing compound C 0.21 parts by mass Ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Co., Ltd.) 8 parts by mass Photopolymerization initiator (Irgacure 907, manufactured by BASF) 5.0 parts by mass Methyl ethyl ketone 200 parts by mass

[0286] [Formation of Second Optically Anisotropic Layer] The alignment film prepared in [Example 1] was continuously subjected to a rubbing treatment. At this time, the longitudinal direction of the long film was parallel to the conveying direction, and the angle between the longitudinal direction of the film (conveying direction) and the rotation axis of the rubbing roller was 105°. The longitudinal direction of the film (conveying direction) was set to 90°, and when observed from the film side, the width direction of the film was set as the reference (0°) and the clockwise direction was expressed as a positive value, so the rotation axis of the rubbing roller was at 75°. In other words, the position of the rotation axis of the rubbing roller was rotated 105° counterclockwise from the longitudinal direction of the film.

[0287] Onto the rubbed alignment film, a composition for forming an optically anisotropic layer (8a) containing a discotic liquid crystal compound of the following composition was applied using a Giesser coater to form a composition layer. The resulting composition layer was then heated with hot air at 60°C for 2 minutes to dry the solvent and ripen the alignment of the discotic liquid crystal compound. Subsequently, the resulting composition layer was irradiated with UV light (70 mJ / cm) at 60°C. ２) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (8a). The thickness of the optically anisotropic layer (8a) was 1.1 μm. The in-plane retardation at 550 nm was 116 nm. The average tilt angle of the discotic plane of the discotic liquid crystal compound with respect to the film surface was 90°, and it was confirmed that the compound was aligned perpendicular to the film surface. The angle of the in-plane slow axis of the optically anisotropic layer (8a) was parallel to the rotation axis of the rubbing roller, and when the width direction of the film was 0° (the longitudinal direction was 90° counterclockwise and −90° clockwise), the in-plane slow axis was 75° when viewed from the optically anisotropic layer (8a) side. The optically anisotropic layer (8a) corresponds to the optically anisotropic layer (C).

[0288] ------------------------------------------------ Optically anisotropic layer-forming composition (8a)------------------------------------------------ 80 parts by mass of the above discotic liquid crystal compound 2------------------------------------------------ 20 parts by mass of the above discotic liquid crystal compound 3------------------------------------------------ 0.30 parts by mass of the above alignment film interface aligning agent 1------------------------------------------------ 0.1 part by mass of the above fluorine-containing compound A------------------------------------------------ 0.05 part by mass of the above fluorine-containing compound B------------------------------------------------ 0.21 parts by mass of the above fluorine-containing compound C------------------------------------------------

[0289] [Preparation of Polarizing Plate] Using the obtained optically anisotropic layer (7a) and optically anisotropic layer (8a), an optical film (7a-8a) was obtained, in which the optically anisotropic layer (7a) - adhesive layer (1d) - optically anisotropic layer (8a) were laminated in this order, using the same method as in Example 1. Next, a polarizing plate P20 including the optical film (7a-8a) and a linear polarizer was prepared using the same method as in Example 1. In the polarizing plate P20, a polarizer protective film, a polarizer, the optically anisotropic layer (7a), the adhesive layer (1d), and the optically anisotropic layer (8a) were laminated in this order, and this corresponds to the polarizing plate of Aspect 2. The angle formed by the absorption axis of the polarizer and the in-plane slow axis of the optically anisotropic layer (7a) was −73°. The angle formed by the in-plane slow axis of the optically anisotropic layer (7a) and the in-plane slow axis of the optically anisotropic layer (8a) was 58°.

[0290] [Example 21] [Formation of First Optically Anisotropic Layer] As in the case of the optically anisotropic layer (1a), an alignment film coated on a cellulose acylate film was continuously subjected to a rubbing treatment. At this time, the longitudinal direction of the long film was parallel to the conveying direction, and the angle between the longitudinal direction of the film (conveying direction) and the rotation axis of the rubbing roller was 75°. The longitudinal direction of the film (conveying direction) was set to 90°, and when observed from the film side, the width direction of the film was used as the reference (0°) and the clockwise direction was expressed as a positive value, so the rotation axis of the rubbing roller was at -15°. In other words, the position of the rotation axis of the rubbing roller was rotated 75° counterclockwise from the longitudinal direction of the film.

[0291] Onto the alignment film subjected to the above-mentioned rubbed treatment, a composition for forming an optically anisotropic layer (9a) containing a rod-shaped liquid crystal compound of the following composition was applied using a Giesser coater to form a composition layer. Thereafter, the obtained composition layer was heated with hot air at 110°C for 2 minutes to dry the solvent and ripen the alignment of the rod-shaped liquid crystal compound. At 60°C, the composition layer was irradiated with 320 nm LED-UV (70 mJ / cm) from the air interface side. ２ ), and an isomerization reaction was carried out. Thereafter, the obtained composition layer was irradiated with UV (100 mJ / cm ) at 80°C. ２) was performed to fix the alignment of the liquid crystal compound, thereby forming an optically anisotropic layer (9a). The thickness of the optically anisotropic layer (9a) was 2.1 μm. The retardation at 550 nm was 220 nm. The angle of the in-plane slow axis of the optically anisotropic layer (9a) was parallel to the rotation axis of the rubbing roller, and when the width direction of the film was 0° (the longitudinal direction was 90° counterclockwise and −90° clockwise), the in-plane slow axis was −15° when viewed from the optically anisotropic layer (9a) side. The optically anisotropic layer (9a) corresponds to the first optically anisotropic layer.

[0292] ---------------------------------------------------------------- Composition (9a) for forming optically anisotropic layer ---------------------------------------------------------------- Rod-shaped liquid crystal compound (A) above 70 parts by mass Rod-shaped liquid crystal compound (C) above 30 parts by mass Ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 10 parts by mass Photopolymerization initiator (Irgacure 907, manufactured by BASF) 3 parts by mass Fluorine-containing compound D above 0.20 part by mass Methyl ethyl ketone 250 parts by mass

[0293] [Preparation of Polarizing Plate] Using the obtained optically anisotropic layer (9a) and the optically anisotropic layer (8a) obtained in [Example 20], an optical film (9a-8a) was obtained in the same manner as in Example 1, in which the optically anisotropic layer (9a) - adhesive layer (1d) - optically anisotropic layer (1j) were laminated in this order. Next, a polarizing plate P21 including the optical film (9a-8a) and a linear polarizer was prepared in the same manner as in Example 1. The polarizing plate P21 has a polarizer protective film, a polarizer, the optically anisotropic layer (9a), the adhesive layer (1d), and the optically anisotropic layer (8a) laminated in this order, and corresponds to the polarizing plate of Aspect 2. The angle formed by the absorption axis of the polarizer and the in-plane slow axis of the optically anisotropic layer (9a) was -75°. The angle formed between the in-plane slow axis of the optically anisotropic layer (9a) and the in-plane slow axis of the optically anisotropic layer (8a) was 15°.

[0294] [Examples 22 and 23] Polarizing plates were prepared in the same manner as in Example 1, except that in the [Formation of the first optically anisotropic layer] of Example 1, the film thickness of the optically anisotropic layer was adjusted to the value shown in the table below.

[0295] Comparative Example 1 A polarizing plate was prepared in the same manner as in Example 1, except that the optically anisotropic layer (1a) in Example 1 was changed to the optically anisotropic layer (2a) in Example 2.

[0296] [Fabrication of Organic EL Display Device] A GALAXY S4 manufactured by SAMSUNG equipped with an organic EL panel was disassembled, the circular polarizing plate was peeled off, and each of the polarizing plates fabricated above was attached to the display device using a pressure-sensitive adhesive so that the polarizer protective film was positioned on the outside, thereby fabricating an organic EL display device.

[0297] [Measurement of refractive index and film thickness of each layer] Reflection ellipsometry was performed on the substrate (the above-mentioned cellulose acylate film) and the laminate in which an alignment film was formed on the substrate. The reflection ellipsometry was performed using the method described in the calculation method of the in-plane birefringence, in-plane refractive index, and thickness of each layer and each region. Next, the wavelength dispersion of the refractive index was calculated according to the Cauchy model, n(λ) = A ｎ +B ｎ / λ ２ (A ｎ and B ｎ (where n(λ) is a variable, λ is the wavelength, and n(λ) is the refractive index at wavelength λ) and the refractive index and film thickness of the substrate were calculated by fitting. Similarly, an optical model was constructed from the measurement results of the obtained refractive index and film thickness of the substrate and the laminate in which an alignment film was formed on the substrate, and the refractive index and film thickness of the alignment film were calculated by fitting. Subsequently, the in-plane birefringence, in-plane refractive index, and thickness of each optically anisotropic layer and isotropic layer were calculated using the above-mentioned method.

[0298] [Evaluation] [In-plane Color Unevenness] The prepared polarizing plate was attached to a black acrylic plate (Acrylite L502 Black, manufactured by Mitsubishi Chemical Corporation) using a pressure-sensitive adhesive, with the polarizer protective film facing outward. Under a rod-shaped fluorescent lamp (FPL-27EX-N), the polarizing plate was set at an azimuth angle, with a diffuser plate in between, such that the long axis direction of the rod-shaped fluorescent lamp and the longitudinal direction of the polarizing plate were perpendicular to each other, and the in-plane color was observed from a polar angle of 30 to 40°. The in-plane color unevenness observed from an oblique angle was evaluated according to the following criteria. The results are shown in the table below. A: No in-plane color unevenness was visible, or only very slight (acceptable). B: Slight in-plane color unevenness was visible, but no problems were encountered in use. (acceptable). C: Slight in-plane color unevenness was visible, but no problems were encountered in use. (Acceptable) D: In-plane color unevenness is visible, but does not cause problems in use (Acceptable) E: In-plane color unevenness is strongly visible and is not acceptable.

[0299] [Air bubbles during lamination] The produced organic EL display device was set to display black and observed under bright light from the front and from a 20° angle, and defects caused by air bubbles were evaluated according to the following criteria. The results are shown in the table below. None: No defects were observed visually, and there are no problems in use. (Acceptable) Yes: Clear circular discoloration marks were present, and the result was unacceptable.

[0300] [Results] The structure, refractive index, film thickness, and evaluation results of the polarizing plates of each Example and Comparative Example are shown in the table below. In the table, when an optically anisotropic layer consists of two layers, it is expressed as "optically anisotropic layer on the polarizer side / optically anisotropic layer on the opposite side to the polarizer side." For example, as in Example 1, when the liquid crystal type column of the second optically anisotropic layer is "rod-shaped / rod-shaped" and the liquid crystal orientation column is "twisted / vertical," this means that the second optically anisotropic layer is formed by laminating, from the polarizer side, a layer formed by fixing a twisted-oriented rod-shaped liquid crystal compound and a layer formed by fixing a vertically aligned rod-shaped liquid crystal compound. The value of ne1 shown in the table indicates the refractive index in the in-plane slow axis direction of the surface of the optically anisotropic layer on the side where the specific region is present. Note that, when no specific region is present, it indicates the refractive index in the in-plane slow axis direction of the surface of the optically anisotropic layer on the isotropic layer A side. The ne2 value shown in the table indicates the refractive index in the in-plane slow axis direction in the region of the specific region of the optically anisotropic layer where the in-plane birefringence is at its maximum value. In Examples 1 to 19 and 22 to 23, the region exhibiting ne2 was present in a layer formed by fixing twistedly aligned rod-shaped liquid crystal compounds, and the value was the same as the refractive index in the in-plane slow axis direction of uniform region 2 present in the layer formed by fixing twistedly aligned rod-shaped liquid crystal compounds. The definition of the refractive index in the in-plane slow axis direction in a layer formed by fixing twistedly aligned rod-shaped liquid crystal compounds is as described above. In the table, the specific region column indicates a region present in the optically anisotropic layer. For example, when Region X is listed, the corresponding first optically anisotropic layer has Region X. In the table, the Isotropic Layer A and Isotropic Layer B columns indicate the physical properties of the isotropic layer adjacent to the specific region present in each Example. For example, in Example 1, it is the isotropic layer A that is a layer adjacent to region X, and in Example 5, it is the isotropic layer B that is a layer adjacent to region Z. Note that in Comparative Example 1, the physical properties of the isotropic layer A between the first optically anisotropic layer and the second optically anisotropic layer are shown.

[0301]

[0302]

[0303] From the results shown in the table above, it was confirmed that when the polarizing plate of the present invention is applied to a display element to obtain a display device, and the display device is set to black display and viewed from an oblique direction, in-plane color unevenness is less likely to occur.

[0304] A comparison of Examples 1-2 and 4-5 confirmed that the effects of the present invention were better when the polarizing plate satisfied two or more of Requirements 1-3. A comparison of Examples 1, 3, and 6-10 confirmed that the effects of the present invention were better when the thicknesses of Region X, Region Y, and Region Z were 60 nm or more, and even better when they were 300 nm or more. A comparison of Examples 1 and 11-15 confirmed that the effects of the present invention were better when the in-plane refractive indexes of Isotropic Layer A and Isotropic Layer B were 1.53 or more, and even better when they were 1.56 to 1.58. A comparison of Examples 1 and 17-19 confirmed that the effects of the present invention were better when the thickness unevenness of Isotropic Layer A and Isotropic Layer B was 35 nm or less, and that bubbles during lamination could be better suppressed when it was 5 nm or more.

[0305] 10, 10A, 10B First optically anisotropic layer 12 Region X 14 Region Z 16 Uniform region 1 20 Second optically anisotropic layer 22 Region Y 24 Uniform region 2 30, 30A, 30B Polarizer 40, 40A, 40B Isotropic layer A 50 Isotropic layer B 25A Optically anisotropic layer (A) 26A Optically anisotropic layer (B) 27B Optically anisotropic layer (C) 100, 100A, 100B Polarizing plate

Claims

1. A polarizing plate having a polarizer, a first optically anisotropic layer, and a second optically anisotropic layer in this order, wherein an isotropic layer A showing optical isotropy is disposed between the first optically anisotropic layer and the second optically anisotropic layer, and satisfies at least one of Requirement 1 and Requirement 2, or an isotropic layer B showing optical isotropy is disposed between the polarizer and the first optically anisotropic layer, and satisfies Requirement 3. Requirement 1: The first optically anisotropic layer has a region X in which the in-plane birefringence gradually increases along the thickness direction from the surface on the isotropic layer A side, and the absolute value of the difference between the refractive index in the in-plane slow axis direction of the surface of the first optically anisotropic layer on the isotropic layer A side and the in-plane refractive index of the isotropic layer A is 0.04 or less. Requirement 2: The second optically anisotropic layer has a region Y in which the in-plane birefringence gradually increases along the thickness direction from the surface on the isotropic layer A side, and the absolute value of the difference between the refractive index in the in-plane slow axis direction of the surface of the second optically anisotropic layer on the isotropic layer A side and the in-plane refractive index of the isotropic layer A is 0.04 or less. Requirement 3: The first optically anisotropic layer has a region Z in which the in-plane birefringence gradually increases along the thickness direction from the surface on the isotropic layer B side, and the absolute value of the difference between the refractive index in the in-plane slow axis direction of the surface of the first optically anisotropic layer on the isotropic layer B side and the in-plane refractive index of the isotropic layer B is 0.04 or less.

2. The polarizing plate according to claim 1, wherein the thicknesses of the region X, the region Y, and the region Z are 60 to 500 nm.

3. The polarizing plate according to claim 1 or 2, wherein the in-plane thickness unevenness of the isotropic layer A and the isotropic layer B is 5 to 35 nm.

4. The polarizing plate according to claim 1 or 2, wherein the first optically anisotropic layer is an A plate.

5. The polarizing plate according to claim 1 or 2, wherein the in-plane retardation of the first optically anisotropic layer at a wavelength of 550 nm is 150 to 240 nm.

6. The polarizing plate according to claim 1 or 2, wherein the first optically anisotropic layer contains a discotic liquid crystal compound.

7. The polarizing plate according to claim 1 or 2, wherein the in-plane refractive indices of the isotropic layer A and the isotropic layer B are 1.51 to 1.

59.

8. The polarizing plate according to claim 1 or 2, wherein the thicknesses of the isotropic layer A and the isotropic layer B are 0.5 to 20 μm.

9. The polarizing plate according to claim 1 or 2, wherein the isotropic layer A and the isotropic layer B are a pressure-sensitive adhesive layer or an ultraviolet curable adhesive layer.

10. A display device including a display element and the polarizing plate according to claim 1 or 2.

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