JP2022003361A - Optical laminate, and polarizing plate, display panel, and image display device using the same - Google Patents

Abstract

To provide an optical laminate that allows an orientation layer and a positive A-layer to be laminated directly and has excellent adhesion properties between the orientation layer and the positive A-layer.SOLUTION: In an optical laminate having an orientation layer and a positive A-layer, the orientation layer and the positive A-layer are in contact, the positive A-layer contains a compound (a), the orientation layer contains the compound (a) shifted from the positive A-layer and other compounds, the compound (a) contains an atom X that the other compounds substantially do not contain, and an average detection amount of the atom X within the orientation layer is 23 or larger when the average detection amount of the atom X within the positive A-layer is standardized 100 on a mass basis.SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical laminate, and a polarizing plate, a display panel, and an image display device using the same.

As an optical film applied to an image display device or the like, there is an optical laminate that imparts a desired phase difference to incident light. For example, a circularly polarizing plate formed by combining a λ / 4 retardation layer and a linearly polarizing plate is used for antireflection of an image display device.

It is well known that such optical laminates do not provide the same effect for all wavelengths.
For example, a circularly polarizing plate formed by laminating a λ / 4 retardation layer and a linear polarizing plate can significantly suppress external light reflection by using light having a wavelength of 550 nm as circularly polarized light, but has a wavelength longer than 550 nm and Since light having a short wavelength is elliptically polarized light, there is a problem that the antireflection function is deteriorated.
As a method for solving this problem, a method has been proposed in which the retardation layer of the circularly polarizing plate is a combination of a λ / 4 retardation layer and a λ / 2 retardation layer.

However, an image display device having a positive A layer such as a λ / 4 retardation layer and a λ / 2 retardation layer has a problem that the display quality (for example, contrast) is deteriorated when visually recognized from an oblique direction.
Therefore, an optical laminate composed of a combination of a positive A layer and a positive C layer has been proposed (Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2006-215221 Japanese Unexamined Patent Publication No. 2016-4142

In Patent Document 1, a layer in which the liquid crystal composition is oriented in-plane on the base material and a layer in which the liquid crystal composition is vertically oriented on the base material are prepared, and these layers are respectively prepared from the base material. It needs to be peeled off and laminated. Therefore, the optical laminate of Patent Document 1 has a problem that the process is complicated. Further, in Patent Document 1, since the positive A layer and the positive C layer are laminated via the adhesive layer or the adhesive layer, the thickness is increased by the amount of the adhesive layer or the adhesive layer, which hinders the thinning. There is.

In Patent Document 2, since the positive A layer and the positive C layer are directly laminated without interposing an adhesive layer or an adhesive layer, the problem of thinning can be solved.
However, the optical laminate of Patent Document 2 often peels off at the interface between the positive A layer and the positive C layer when it is attached to another member. Further, among the optical laminates of Patent Document 2, the embodiment in which the positive C layer and the positive A layer are formed on the peelable base material and the positive C layer and the positive A layer are transferred to other members is available. During transfer, there were many cases where the positive A layer and the positive C layer were separated.

The present invention is an optical laminate in which an oriented layer such as a positive C layer and a positive A layer are directly laminated and have excellent adhesion between the oriented layer and the positive A layer, and a display using the same. It is an object of the present invention to provide a panel and an image display device.

The present invention provides the following [1] to [4].
[1] An optical laminate having an alignment layer and a positive A layer, wherein the alignment layer and the positive A layer are in contact with each other, the positive A layer contains a compound a, and the alignment layer is the positive A. The compound a that is transferred from the layer and other compounds are contained, and the compound a contains an atom X that is substantially not contained in the other compound, and the average detection of the atom X in the positive A layer is performed. An optical laminate in which the average detection amount of the atom X in the alignment layer is 23 or more when the amount is standardized to 100 on a mass basis.
[2] A polarizing plate having a polarizing element, a transparent protective plate A arranged on one side of the polarizing element, and a transparent protective plate B arranged on the other side of the polarizing element. A polarizing plate in which either one of the transparent protective plate A and the transparent protective plate B is the optical laminate according to the above [1].
[3] A display panel in which the optical laminate according to the above [1] is arranged on a light emitting surface of a display element.
[4] An image display device including the display panel according to the above [3].

According to the optical laminate of the present invention, and the display panel and image display device using the same, the alignment layer and the positive A layer are directly laminated, so that the optical laminate can be made thinner and thinner. Since the adhesion between the alignment layer and the positive A layer is excellent, workability, stability over time, and the like can be improved.

It is sectional drawing which shows one Embodiment of the optical laminated body of this invention. It is sectional drawing which shows one Embodiment of the polarizing plate of this invention. It is sectional drawing which shows one Embodiment of the display panel of this invention.

Hereinafter, embodiments of the present invention will be described.
In the present specification, the notation "AA to BB" means "AA or more and BB or less".

Further, in the present specification, "in-plane phase difference at wavelength 450 nm" is "Re (450)", "in-plane phase difference at wavelength 550 nm" is "Re (550)", and "in-plane phase difference at wavelength 650 nm". May be referred to as "Re (650)", and "phase difference in the thickness direction at a wavelength of 550 nm" may be referred to as "Rht (550)".
The in-plane phase difference (Re) and the phase difference (Rth) in the thickness direction can be calculated from Nx, Ny, Nz and the thickness d (nm) of the phase difference layer by the following formula.
In-plane phase difference (Re) = (Nx-Ny) x d
Phase difference in the thickness direction (Rth) = ((Nx + Ny) /2-Nz) × d

Further, in the present specification, the positive A layer means that the refractive index in the X-axis direction, which is the axial direction having the highest refractive index along the in-plane of the layer, is Nx, and the refractive index in the direction along the in-plane of the layer is the X-axis. When the refractive index in the orthogonal Y-axis direction is Ny and the refractive index in the thickness direction of the layer is Nz, the layer satisfies the relationship of Nx> Ny≈Nz. Further, in the present specification, the positive C layer is a layer satisfying the relationship of Nx≈Ny <Nz.

[Optical laminate]
The optical laminate of the present invention comprises an alignment layer and a positive A layer, the alignment layer and the positive A layer are in contact with each other, the positive A layer contains the compound a, and the alignment layer is the above. The compound a transitioned from the positive A layer and other compounds are included.
The compound a contains an atom X that is substantially free of the other compounds.
When the average detected amount of the atom X in the positive A layer is standardized to 100 on a mass basis, the average detected amount of the atom X in the oriented layer is 23 or more.

FIG. 1 is a cross-sectional view showing an embodiment of the optical laminate of the present invention.
The optical laminate 100 of FIG. 1 has an alignment layer 20 and a positive A layer 30, and the alignment layer 20 and the positive A layer 30 are in contact with each other. Further, in the optical laminate of FIG. 1, the alignment layer 20 and the positive A layer 30 are formed on the base material 10.

The optical laminate of the present invention has an alignment layer and a positive A layer, and the alignment layer and the positive A layer are in contact with each other. As described above, in the optical laminate of the present invention, the alignment layer and the positive A layer are directly laminated without interposing an adhesive layer or the like, so that the optical laminate can be made thinner and optical. The laminate can be easily manufactured.

<Average amount of atom X detected in the oriented layer>
The optical laminate of the present invention is required to have the following configurations (1) to (3), and the average detected amount of atoms X in the alignment layer must satisfy the following conditions (4).
(1) The positive A layer contains compound a.
(2) The alignment layer contains the compound a formed by migrating from the positive A layer and other compounds.
(3) The compound a contains an atom X that is substantially not contained in the other compounds.
(4) When the average detected amount of the atom X in the positive A layer is standardized to 100 on a mass basis, the average detected amount of the atom X in the oriented layer is 23 or more.

Compound a means a liquid crystal compound contained in the positive A layer. Examples of the atom X contained in the compound a include a sulfur atom and a nitrogen atom.
Further, the other compounds mean all the compounds excluding the compound a from the compounds constituting the alignment layer.
Further, in the present specification, the average detected amount in (4) above may be referred to as "average detected amount of the oriented layer".

When the average detection amount of the oriented layer satisfies the condition of (4) above, it means that the compound a of the positive A layer has penetrated into the oriented layer in excess of a predetermined ratio. As described above, when the compound a in the positive A layer permeates the oriented layer in excess of a predetermined ratio, the affinity between the positive A layer and the oriented layer is increased and an anchoring effect is produced. Therefore, the optical laminate of the present invention having the above configurations (1) to (3) and satisfying the above condition (4) can improve the adhesion between the positive A layer and the alignment layer. can.
On the other hand, the optical laminate that does not satisfy the condition (4) above cannot improve the adhesion between the positive A layer and the alignment layer, and is positive due to the stress generated during the bonding work and the transfer work. Peeling occurs at the interface between the A layer and the alignment layer.

The average detection amount of the oriented layer is preferably 27 or more, more preferably 30 or more, and further preferably 33 or more.
As the average detection amount of the oriented layer is increased, the adhesion is gradually improved, but there is a limit to the improvement of the adhesion. Further, since the compound a enters the gap of the alignment structure of the alignment layer, the orientation of the alignment layer is not easily affected by the compound a that has penetrated into the alignment layer. However, if the average detection amount of the oriented layer becomes too large, it may be difficult for the positive A layer to be oriented, or problems may occur due to changes in various physical properties of the oriented layer. Therefore, the average detection amount is preferably 60 or less, more preferably 50 or less, and even more preferably 40 or less.

The average detected amount of the oriented layer can be increased or decreased depending on, for example, the molecular weight of the compound a in the positive A layer, the affinity between the oriented layer and the positive A layer, the solvent of the coating liquid for forming the positive A layer, and the like. Specifically, the smaller the molecular weight of the compound a, the larger the average detected amount, and the larger the molecular weight of the compound a, the smaller the average detected amount. Further, the higher the affinity between the alignment layer and the positive A layer, the larger the average detection amount, and the lower the affinity, the smaller the average detection amount. Further, the higher the permeability of the coating liquid for forming the positive A layer into the alignment layer, the larger the average detection amount, and the lower the permeability of the solvent into the alignment layer, the smaller the average detection amount tends to be. Further, the larger the mass ratio of the solvent of the coating liquid for forming the positive A layer, the larger the average detection amount, and the lower the mass ratio of the solvent of the coating liquid, the smaller the average detection amount tends to be (the solvent of the coating liquid). Weight ratio ≒ total amount of coating liquid-mass ratio of solid content of coating liquid).
Further, as will be described later, a specific liquid crystal compound is used as the compound constituting the alignment layer such as the positive C layer, and when the compound a is a compound containing a sulfur atom, the average detection amount can be easily increased. Further, as will be described later, when the compound a has a molecular structure that is easy to move, the average detection amount can be easily increased.

For the mass-based detection amount of atom X in the positive A layer and the alignment layer, a measurement sample of flakes obtained by cutting the optical laminate in the vertical direction is prepared, and the scanning electron microscope-energy is obtained from the cross-sectional side of the sample. It can be measured by distributed X-ray spectroscopy (SEM-EDX). It is preferable to prepare 20 measurement samples and use the average value of the 20 measured values as various parameters related to the detected amount of the atom X.
As the sample for measuring flakes, for example, a cut sample obtained by cutting an optical laminate to a predetermined size can be prepared, and the cut sample can be vertically cut with a diamond knife. The thickness of the thin section measurement sample is preferably 40 nm to 160 nm.

In the measurement by the SEM-EDX analyzer, the quantitative conditions unique to each device (for example, the SEM "SU8000" manufactured by Hitachi High-Technologies and the EDX "XMAX80" manufactured by Oxford Instruments have an acceleration voltage of 30 kV, a focal distance of 15 mm, and a sample. It is preferable to obtain the characteristic X-ray spectrum by appropriately adjusting the irradiation current and the measurement time so that the target element can be sufficiently detected according to the inclination (0 degree). Further, the concentration of each element can be determined by a ZAF correction method (a method of applying atomic number correction Z, absorption correction A, and fluorescence correction F to the relative intensity of each element to obtain the content of each element).

In the present specification, the above-mentioned measurement regarding the detected amount of atom X, and other measurements and evaluations shall be carried out in an atmosphere of a temperature of 23 ° C. ± 5 ° C. and a humidity of 40% to 65%, unless otherwise specified. do. In addition, the sample shall be exposed to the atmosphere for at least 30 minutes prior to measurement and evaluation.

<Ratio of variation coefficient and variation of detected amount>
In the optical laminate of the present invention, it is preferable that the amount of the atom X detected in the alignment layer satisfies the following condition 1.
(Condition 1)
The amount of the atom X in the alignment layer is detected at 100 points every 26 nm in the direction parallel to the interface at a position of 200 nm in the thickness direction from the interface between the alignment layer and the positive A layer. The coefficient of variation based on the mass of the detected amount of the atom X at the 100 locations is 0.16 or more.

Satisfying the condition 1 means that the amount of the compound A permeated into the alignment layer varies depending on the location of the alignment layer, and the degree of variation is more than a predetermined value. In this way, by varying the permeability of the compound A depending on the location of the alignment layer, the adhesion between the alignment layer and the positive A layer can be further improved.
The coefficient of variation of condition 1 is preferably 0.20 or more, and more preferably 0.25 or more.
The upper limit of the coefficient of variation under Condition 1 is preferably 0.60 or less, more preferably 0.50 or less, and more preferably 0.40 or less, from the viewpoint of suppressing fluctuations in physical properties in a fine region. It is more preferably 0.35 or less, and even more preferably 0.35 or less.
The coefficient of variation is a dimensionless parameter obtained by dividing the standard deviation (variation) by the average value.

In the optical laminate of the present invention, it is preferable that the amount of the atom X detected in the positive A layer and the alignment layer satisfies the following condition 2.
(Condition 2)
The amount of the atom X in the positive A layer is detected at 100 points every 26 nm in the direction parallel to the interface at a position of 200 nm in the thickness direction from the interface between the positive A layer and the oriented layer. The coefficient of variation based on the mass of the detected atom X is defined as CV1.
The amount of the atom X in the alignment layer is detected at 100 points every 26 nm in the direction parallel to the interface at a position of 200 nm in the thickness direction from the interface between the alignment layer and the positive A layer. The coefficient of variation based on the mass of the detected atom X is defined as CV2.
The ratio of the CV1 to the CV2 (CV2 / CV1) is 2.00 or more.

Satisfying condition 2 means that, as in condition 1, the amount of compound A permeated into the alignment layer varies depending on the location of the alignment layer, and the degree of variation is equal to or higher than a predetermined level. .. In this way, by varying the permeability of the compound A depending on the location of the alignment layer, the adhesion between the alignment layer and the positive A layer can be further improved.
The ratio of condition 2 is preferably 2.10 or more, and more preferably 2.20 or more.
The upper limit of the ratio of condition 2 is preferably 4.00 or less, more preferably 3.00 or less, and further preferably 2.50 or less, from the viewpoint of suppressing fluctuations in physical properties in the fine region. preferable.

Conditions 1 and 2 can be adjusted by, for example, the in-plane uniformity of the degree of orientation of the alignment layer. Specifically, the lower the in-plane uniformity of the alignment degree of the alignment layer, the larger the ratio of the coefficient of variation of condition 1 and the condition 2 tends to be, and the higher the in-plane uniformity of the orientation degree of the alignment layer, the higher the in-plane uniformity. The coefficient of variation of condition 1 and the ratio of condition 2 tend to be small.

<Orientation layer>
The alignment layer is arranged at a position in contact with the positive A layer in the thickness direction of the optical laminate.
When forming the alignment layer and the positive A layer on the substrate, it is preferable to first form the alignment layer on the substrate and then form the positive A layer.

Further, the alignment layer contains the compound a transitioned from the positive A layer and other compounds. The other compounds are all the compounds except the compound a from the compounds constituting the alignment layer. The main component of the other compound is a liquid crystal compound, and the liquid crystal compound is preferably a liquid crystal compound having a photosensitive group.
The other compounds do not substantially contain the atom X contained in the compound a. In the present specification, the fact that the other compound does not substantially contain the atom X means 0.1% by mass or less of the total amount of the other compound, and more preferably 0.01% by mass or less.

Examples of the oriented layer include a homeotropic oriented layer.
The homeotropic orientation is a state in which the liquid crystal compound is oriented parallel and uniformly with respect to the normal direction of the layer, that is, a state in which the liquid crystal compound is vertically oriented.
A typical example of the homeotropically oriented layer is the positive C layer. That is, as the orientation layer, a positive C layer can be mentioned.
Hereinafter, embodiments of the positive C layer, which is a representative example of the oriented layer, will be mainly described.

The liquid crystal compound of the positive C layer may be a material made of a liquid crystal polymer or a material made of a liquid crystal monomer.
The liquid crystal compound of the positive C layer is preferably a liquid crystal compound having a photosensitive group from the viewpoint of the orientation of the positive A layer formed on the positive C layer. That is, the alignment layer preferably contains a liquid crystal compound having a photosensitive group as another compound.

As used herein, the photosensitive group refers to a functional group that binds to another molecule by irradiation with light. Further, in the present specification, the liquid crystal compound shows liquid crystallinity when a physical external stimulus (heating, cooling, electric field, magnetic field, application of shear, etc.) is applied to the material alone, or is a solvent or non-liquid crystallinity. A material that develops liquid crystallinity when mixed with components.

Examples of the liquid crystal compound having a photosensitive group include a photosensitive side chain type liquid crystal polymer having a side chain containing a structure in which the following (i) and (ii) are bonded with or without a spacer. As the liquid crystal compound having such a photosensitive group, those described in JP-A-2016-4142 can also be used.
(I) A photosensitive group such as a cinnamoyl group, a chalcone group, a cinnamylden group, a biphenylacryloyl group, a frillacryloyl group, a naphthylacryloyl group (or a derivative thereof).
(Ii) Substituents such as biphenyl, terphenyl, phenylbenzoate, and azobenzene, which are often used as the mesogen component of liquid crystal polymers.

The photosensitive side chain type liquid crystal polymer has a photosensitive side chain having a carboxyl group at the end of the side chain, and forms a rigid structure by dimerization of the carboxyl group at the end of the side chain by hydrogen bonding. Examples thereof include polymers that do not contain a mesogen group in the chain itself and exhibit liquidity.
Examples of the main chain constituting the photosensitive side chain type liquid crystal polymer include hydrocarbons, acrylates, methacrylates, siloxanes, maleimides, N-phenylmaleimides and the like in which the side chains are bonded via spacers. These polymers are single polymers of the same repeating unit, copolymers of multiple units with side chains of different structures, or units with side chains containing photosensitive groups that do not contain photosensitive groups. It may be any of the copolymers obtained by blending the unit having a chain to the extent that the liquidity is not impaired. In addition, a small molecule compound may be added to enhance the orientation.

The photosensitive side chain type liquid crystal polymer may be a polymer having a crosslinked structure introduced by a crosslinking agent such as an isocyanate material and an epoxy material for the purpose of improving heat resistance.

The photosensitive side chain type liquid crystal polymer is preferably a polymer formed by using a monomer having a side chain represented by the following general formulas (1) to (3).
The polymer formed by using the monomers having side chains represented by the following general formulas (1) to (3) has a high affinity with a compound containing a sulfur atom. That is, the oriented layer such as the positive C layer contains a polymer formed by using the monomers having side chains represented by the following general formulas (1) to (3), and the compound a of the positive A layer contains a sulfur atom. In this case, it is preferable that the compound a easily penetrates into the positive C layer and the detected amount of the atom X (for example, sulfur) easily satisfies the above range.

In each of the chemical formulas 1 and 2, n represents an integer of 1 to 12, m represents an integer of 1 to 12, and X or Y is none, -COO, -OCO-, -N = N-, -C =. C- or -C ₆ H ₄ - represents respectively, W ₁ is cinnamoyl group, a chalcone group, Shin'namiridenki group, biphenyl acryloyl group, a furyl acryloyl group, naphthyl acrylate or represents acryloyl group or a derivative thereof, or, -H , -OH, or -CN, where W ₂ represents a cinnamoyl group, a chalcone group, a cinnamyldenki group, a biphenylacryloyl group, a frillacryloyl group, a naphthylacryloyl group or a derivative thereof, or -H,- Represents OH or -CN. In each of the general formulas (1) and (2), n represents an integer of 1 to 12, m represents an integer of 1 to 12, and X or Y is a single bond, −COO, −OCO−. , -N = N -, - C = C- or _-C 6 _{H 4} - indicates, _{W 1} is cinnamoyl group, a chalcone group, cinnamylidene group, biphenyl acryloyl group, a furyl acryloyl group, naphthyl acryloyl group and derivatives thereof , Or -H, -OH and -CN, where W ₂ is a cinnamoyl group, chalcone group, cinnamylidene group, biphenylacryloyl group, frillacryloyl group, naphthylacryloyl group and derivatives thereof, or -H, -OH. And -CN are shown.

Among the side chains represented by the above formulas, _{monomers in which W 1} and W ₂ have side chains represented by -H, -OH and -CN do not exhibit photosensitivity, but have photosensitive groups on the side chains. By copolymerizing with the monomer having a photosensitive group, a liquid crystal polymer having a photosensitive group can be obtained. In the case of copolymerization, the higher the proportion of the non-photosensitive monomer represented by the above formula, the easier it is to obtain a polymer that is easily homeotropic oriented. Can be set as appropriate.

In the general formula (3), s represents 0 or 1, t represents an integer of 1 to 3, and R represents H, an alkyl group, an alkyloxy group or a halogen.

The oriented layer such as the positive C layer may contain additives such as a light stabilizer and an antioxidant as long as the effect of the present invention is not impaired.

In the positive C layer, for example, a component constituting the positive C layer (for example, a liquid crystal polymer formed from a monomer unit having a side chain represented by the general formulas (1) to (3), an additive) is dissolved in a solvent. Alternatively, it can be formed by preparing a diluted coating liquid for the positive C layer, applying the coating liquid on the substrate, and drying the coating liquid.

Examples of the solvent for the coating liquid for the positive C layer include dioxane, dichloroethane, cyclohexanone, toluene, tetrahydrofuran, o-dichlorobenzene, methyl ethyl ketone, methyl isobutyl ketone and the like, and these solvents are used alone or in combination.

In the process of applying the coating liquid for the positive C layer onto the substrate and removing the solvent, the positive C layer begins to show homeotropic orientation, and after drying, further heating is performed to enhance the homeotropic orientation. Specifically, homeotropic orientation is induced by heating and cooling to a temperature equal to or higher than the liquid crystal phase transition temperature and lower than or equal to the isotropic transition temperature (preferably lower than the isotropic transition temperature).
Further, the homeotropically oriented layer is irradiated with linearly polarized ultraviolet rays. By irradiating with linearly polarized ultraviolet rays, the photoreaction of the photosensitive group of the liquid crystal polymer having a photosensitive group proceeds anisotropically, and the liquid crystal alignment ability for orienting the liquid crystal compound of the positive A layer is imparted. The wavelength of the irradiation light is preferably 200 nm to 500 nm, more preferably 250 nm to 400 nm. Even if such linearly polarized ultraviolet irradiation is performed, the orientation of the homeotropic alignment layer is substantially unaffected.

It is preferable to irradiate the positive C layer with the linearly polarized ultraviolet rays and then to irradiate the non-polarized ultraviolet rays after forming the positive A layer on the positive C layer. When irradiated with non-polarizing ultraviolet rays, the dimerization of the liquid crystal polymer having a photosensitive group proceeds, the orientation is fixed, and a stable homogeneous alignment layer is formed. Since the homeotropic orientation of the positive A layer is completed before the irradiation of the non-polarized ultraviolet rays, it can be said that the homeotropic orientation of the positive A layer is not substantially disturbed by the non-polarized ultraviolet rays. Further, by irradiating with non-polarizing ultraviolet rays, it can be expected that the photosensitive groups of the positive C layer and the photosensitive groups of the positive A layer react with each other to further improve the adhesion.

The oriented layer such as the positive C layer preferably has Rht (550) of -100 nm to -50 nm, and more preferably −90 nm to -60 nm. By setting the Rht (550) of the oriented layer to the relevant range, it is possible to easily improve the visibility in the oblique direction.

The oriented layer such as the positive C layer preferably has a small Re (550), preferably 20 nm or less, more preferably 10 nm or less, still more preferably 5 nm or less, still more preferably 1 nm or less.

In the present specification, the in-plane phase difference, the phase difference in the thickness direction, the haze and the total light transmittance mean the average value of the measured values at 16 points. The 16 measurement points are measured at 16 points of intersections when a line 1 cm from the outer edge of the measurement sample is set as a margin and a line that divides the vertical direction and the horizontal direction into five equal parts is drawn with respect to the area inside the margin. It is preferable to use it as the center of. When the measurement sample is a quadrangle, the measurement is performed centering on 16 points of intersections of lines 1 cm from the outer edge of the quadrangle and the area inside the margin divided into 5 equal parts in the vertical and horizontal directions. , It is preferable to calculate the average value. If the measurement sample has a shape other than a quadrangle such as a circle, an ellipse, a triangle, or a pentagon, a quadrangle with the maximum area inscribed in these shapes can be drawn, and 16 points can be measured for the quadrangle by the above method. preferable.
The in-plane phase difference and the phase difference in the thickness direction can be measured by, for example, the trade name "KOBRA-WR" manufactured by Oji Measurement Co., Ltd.

The thickness of the alignment layer such as the positive C layer is preferably 100 nm to 5 μm, more preferably 50 nm to 3 μm, and further preferably 100 nm to 2 μm.
The thickness of each layer such as the alignment layer such as the positive C layer, the positive A layer, and the base material is measured as an average value of 20 points by observing a cross-sectional image of the optical laminate with a scanning transmission electron microscope (STEM) or the like. Can be calculated.

<Positive A layer>
The positive A layer is arranged at a position in contact with the positive C layer in the thickness direction of the optical laminate. Further, the positive A layer contains compound a.

Compound a contains an atom X that is substantially free of other compounds contained in the positive C layer. Examples of the atom X contained in the compound a include a sulfur atom and a nitrogen atom, and a sulfur atom is preferable.
The positive A layer is preferably formed from a liquid crystal compound. The liquid crystal compound is preferably a polymerizable liquid crystal compound. That is, the compound a is preferably a liquid crystal compound, more preferably a polymerizable liquid crystal compound. Further, the compound a is preferably a polymerizable liquid crystal compound containing a sulfur atom or a nitrogen atom as the atom X, and more preferably a polymerizable liquid crystal compound containing a sulfur atom as the atom X.

The positive A layer is a layer showing homogenius orientation. Homogeneous orientation refers to a state in which liquid crystal materials are arranged parallel to the layer surface and in the same direction (optical uniaxiality). The liquid crystal compound that can be homogenically oriented may be a material made of a liquid crystal polymer or a material made of a liquid crystal monomer.
As described above, when the positive C layer oriented homeotropically is irradiated with linearly polarized ultraviolet rays, the photoreaction of the photosensitive group of the liquid crystal polymer having a photosensitive group proceeds heterogeneously, and the positive A layer The liquid crystal alignment ability for orienting the liquid crystal compound is imparted. Therefore, even if the positive A layer coating liquid is directly applied, dried and cured on the positive C layer, a homogenically oriented positive A layer can be obtained on the homeotropically oriented positive C layer.

In the positive A layer, it is preferable that Re (450), Re (550) and Re (650) satisfy the following relationship (i). That is, the positive A layer preferably has reverse dispersibility. By using a dedispersible layer that satisfies the relationship (i) below as the positive A layer, it is possible to easily impart dedispersity to the entire optical laminate including the positive A layer and the positive C layer. Visibility, antireflection, and the like in a wavelength range outside 550 nm can be easily improved.
Re (450) <Re (550) <Re (650) (i)

Re (450), Re (550) and Re (650) of the positive A layer are not particularly limited, but when the positive A layer is a λ / 4 retardation layer, the positive A layer is set to λ within the following range. In the case of a / 2 retardation layer, it is preferably in the following range.

<< In the case of λ / 4 phase difference layer >>
Re (450) is preferably 82 nm to 143 nm, more preferably 90 nm to 135 nm. Re (550) is preferably 100 nm to 175 nm, more preferably 110 nm to 165 nm. Re (650) is preferably 119 nm to 206 nm, more preferably 130 nm to 195 nm.
Further, in the laminated body of the positive A layer (λ / 4 retardation layer) and the positive C layer, the Rth (550) is preferably -40 nm to 40 nm, and more preferably -25 nm to 25 nm.

<< In the case of λ / 2 phase difference layer >>
Re (450) is preferably 165 nm to 286 nm, more preferably 180 nm to 270 nm. Re (550) is preferably 201 nm to 349 nm, more preferably 220 nm to 230 nm. Re (650) is preferably 237 nm to 412 nm, more preferably 260 nm to 390 nm.
Further, in the laminated body of the positive A layer (λ / 2 retardation layer) and the positive C layer, the Rth (550) is preferably -50 nm to 50 nm, and more preferably -30 nm to 30 nm.

The thickness of the positive A layer is preferably 100 nm to 5 μm, more preferably 500 nm to 4 μm, and even more preferably 1.5 μm to 3.0 μm.

The dedispersible positive A layer can be formed from a liquid crystal compound exhibiting dedispersity. Such a liquid crystal compound is preferably one having a polymerizable property.
Examples of the polymerizable liquid crystal compound exhibiting dedispersity include those represented by the general formula (1) of JP-A-2019-73712 and those represented by the general formula (II) of International Publication No. WO2017 / 043438. Can be mentioned.

Specific examples of the polymerizable liquid crystal compound exhibiting reverse dispersibility include compounds represented by the following chemical formulas (4) to (29). The compounds represented by the following chemical formulas (4) to (29) all contain a sulfur atom and a nitrogen atom in the molecule.
Since the compounds represented by the following chemical formulas (4) to (29) have a structure in which the left and right molecular structures are easily moved around the biphenyl group, they easily permeate into the alignment film, and the atoms X in the alignment film It is preferable because the average detection amount can be easily set in the above range.

The positive A layer may contain additives such as a light stabilizer and an antioxidant as long as the effects of the present invention are not impaired.

For the positive A layer, for example, a coating solution for the positive A layer prepared by dissolving or diluting the components constituting the positive A layer in a solvent is prepared, the coating solution is applied onto the positive C layer, dried, and if necessary. It can be formed by irradiating it with ionizing radiation and curing it.

The solvent of the coating liquid for the positive A layer is, for example, ketones (acetone, methylethylketone, methylisobutylketone, cyclohexanone, etc.), ethers (dioxane, tetrahydrofuran, 1,3-dioxolane, etc.), aliphatic hydrocarbons (hexane, etc.). ), Alicyclic hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), carbon halides (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), Alcohols (isopropanol, butanol, cyclohexanol, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), glycol ethers (propylene glycol monomethyl ether acetate, etc.), cellosolve acetates, sulfoxides (dimethylsulfoxide, etc.), amides (Dimethylformamide, dimethylacetamide, etc.) and the like can be exemplified, and a mixture thereof may be used.

Among the above solvents, methyl isobutyl ketone, cyclohexanone, 1,3-dioxolane, toluene and the like are preferable, and among them, cyclohexanone and 1,3-dioxolane, which have high polarity and easily penetrate into the alignment layer, are more preferable.

The ratio of the solvent in the coating liquid for the positive A layer is preferably 70% by mass to 95% by mass, and more preferably 75% by mass to 90% by mass.

<Base material>
The optical laminate may have a base material.
As the base material, a plastic film is preferable.
Examples of the polymer constituting the plastic film include cellulose acylate, polycarbonate polymer, polyester polymer such as polyethylene terephthalate and polyethylene naphthalate, acrylic polymer such as polymethyl methacrylate, polystyrene and acrylonitrile / styrene copolymer (AS resin). Such as styrene-based polymers, polyethylene, polypropylene, polyolefin-based polymers such as ethylene-propylene copolymer, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamide, imide-based polymers, sulfone-based polymers, polyether sulfone-based Examples thereof include polymers, polyether ether ketone polymers, polyphenylene sulfide polymers, vinylidene chloride polymers, vinyl alcohol polymers, vinyl butyral polymers, allylate polymers, polyoxymethylene polymers and epoxy polymers.

Considering the thinning of the image display device, the base material is preferably one in which the alignment layer and the positive A layer can be peeled off. By using a peelable substrate, the alignment layer and the positive A layer can be transferred to other members of the image display device.
Since the optical laminate of the present invention has good adhesion between the alignment layer and the positive A layer, it is possible to suppress the separation of the interface between the alignment layer and the positive A layer due to the stress generated during transfer, so that the optical laminate can be peeled off. It is preferable because it is easy to apply the base material.
Examples of the peelable base material include the plastic film itself or one obtained by releasing the surface of the plastic film with a general-purpose mold release agent or the like.

The thickness of the base material is usually about 25 μm to 150 μm, preferably 30 μm to 125 μm, and more preferably 40 μm to 100 μm.

<Other layers>
The optical laminate may have other layers as long as the effects of the present invention are not impaired. Examples of other layers include a gas barrier layer, an adhesive layer, and a retardation layer.

<Physical characteristics of optical laminate>
In the optical laminate of the present invention, the in-plane phase difference of the optical laminate at a wavelength of 450 nm is Re (450), the in-plane phase difference of the optical laminate at a wavelength of 550 nm is Re (550), and the surface of the optical laminate at a wavelength of 650 nm. When the internal phase difference is defined as Re (650), it is preferable to satisfy the relationship of the following formula (A).
Re (450) <Re (550) <Re (650) (A)

By satisfying the formula (A), the optical laminate as a whole exhibits reverse wavelength dispersion characteristics, and it is possible to easily improve visibility, antireflection, and the like in a wavelength range outside 550 nm.

In the optical laminate, the haze of JIS K7136: 2000 is preferably 1.0% or less, more preferably 0.9% or less, and further preferably 0.8% or less.
Further, in the optical laminate, the total light transmittance of JIS K7361-1: 1997 is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more.

The total thickness of the optical laminate is not particularly limited, but is preferably 15 μm to 300 μm, more preferably 20 μm to 200 μm, and more preferably 25 μm to 100 μm from the viewpoint of improving handleability and mechanical strength. Is even more preferable.

<Size, shape, etc.>
The optical laminate may be in the form of a single leaf or a roll.
The size of the single leaf is not particularly limited, but generally, the size is about 2 inches to 500 inches diagonally. The width and length of the roll are not particularly limited, but are generally 500 mm to 3000 mm in width and 500 m to 5000 m in length.
Further, the shape of the single leaf is not particularly limited, and may be, for example, a polygon (triangle, quadrangle, pentagon, etc.), a circle, or a random irregular shape.

[Polarizer]
The polarizing plate of the present invention has a polarizing plate, a transparent protective plate A arranged on one side of the polarizing element, and a transparent protective plate B arranged on the other side of the polarizing element. However, either one of the transparent protective plate A and the transparent protective plate B is the above-mentioned optical laminate of the present invention.

FIG. 2 is a cross-sectional view showing an embodiment of the polarizing plate of the present invention.
The polarizing plate 200 of FIG. 2 has a polarizing element 50, a transparent protective plate A (61) arranged on one side of the polarizing element, and a transparent protective plate B arranged on the other side of the polarizing element. (62) and. Further, the transparent protective plate A (61) in FIG. 2 is an optical laminate 100.

<Polarizer>
Examples of the polarizing element include sheet-type polarizing elements such as a polyvinyl alcohol film dyed and stretched with iodine, a polyvinyl alcohol film, a polyvinyl acetal film, an ethylene-vinyl acetate copolymerization system saponification film, and a large number arranged in parallel. Examples thereof include a wire grid type polarizing element made of the metal wire of the above, a lyotropic liquid crystal, a coated type polarizing element coated with a dichroic guest-host material, and a multilayer thin film type polarizing element. In addition, these polarizing elements may be a reflection type polarizing elements having a function of reflecting a polarization component which does not transmit.

<Transparent protective plate>
A transparent protective plate A is arranged on one side of the polarizing element, and a transparent protective plate B is arranged on the other side. One of the transparent protective plate A and the transparent protective plate B is the above-mentioned optical laminate of the present invention.

Examples of the transparent protective plate A and the transparent protective plate B other than the optical laminate include a plastic film and glass. Examples of the plastic film include a polyester film, a polycarbonate film, a cycloolefin polymer film and an acrylic film, and these stretched films are preferable from the viewpoint of mechanical strength. Examples of the glass include alkaline glass, nitrided glass, soda-lime glass, borosilicate glass, lead glass and the like. Further, it is preferable that the glass as a transparent protective plate that protects the polarizing element is also used as another member of the image display device (for example, a glass substrate of a liquid crystal display element, a surface plate of an image display device).
It is preferable that the polarizing element and the transparent protective plate are bonded to each other via an adhesive. As the adhesive, a general-purpose adhesive can be used, and a PVA-based adhesive is preferable.

The polarizing plate of the present invention is preferably used as a polarizing plate arranged on the light emitting surface side of the display element. Further, when used as described above, it is preferable to use the transparent protective plate on the light incident surface side as the above-mentioned optical laminate of the present invention with reference to the polarizing element. From the viewpoint of making the polarizing plate function as a circular polarizing plate, the direction of the slow axis of the positive A layer with respect to the absorption axis of the polarizing element is preferably in the range of 30 ° to 60 °, and is preferably 40 ° to 50 °. It is more preferable to set the range.

[Display panel]
The display panel of the present invention is formed by arranging the above-mentioned optical laminate of the present invention on the surface of the display element on the light emitting surface side.

FIG. 3 is a cross-sectional view showing an embodiment of the display panel 500 of the present invention. In the display panel 500 of FIG. 3, the optical laminate 100 is laminated on the surface of the display element 300 on the light emitting surface side.

When the display element of the display panel is a liquid crystal display element, a backlight (not shown) is required on the back surface of the liquid crystal display element. As the backlight, either an edge light type backlight or a direct type backlight can be used. Further, examples of the light source of the backlight include LEDs and CCFLs, and a backlight using quantum dots as the light source is preferable because it is easy to improve color reproducibility.

The display panel preferably has a polarizing element on the surface of the optical laminate opposite to the display element. By adopting such a configuration, it is possible to impart an external light reflection prevention function to the image display device and prevent the color from being impaired when visually recognized from an angle.

<Display element>
Examples of the display element include a liquid crystal display element, an organic EL display element, an inorganic EL display element, a plasma display element, an electronic paper display element, an LED display element (micro LED, etc.), a display element using quantum dots, and the like. These display elements may have a touch panel function inside the display element.

[Image display device]
The image display device of the present invention is not particularly limited as long as it includes the display panel of the present invention, but includes the display panel of the present invention, a drive control unit electrically connected to the display panel, and the like. It is preferable to provide a housing.

The image display device may be a foldable type image display device or a rollable type image display device. Further, the image display device may be an image display device with a touch panel.

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. In addition, "part" and "%" are based on mass unless otherwise specified.

1. 1. Measurement and evaluation The following measurements and evaluations were performed on the optical laminates obtained in Examples and Comparative Examples. The results are shown in Table 1.

1-1. Measurement of Sulfur Atoms A cut sample was prepared by cutting the optical laminates of Examples and Comparative Examples to a predetermined size, and an embedded sample was prepared by embedding the cut sample with an epoxy resin. Next, 20 flaky measurement samples (thickness 0.08 μm) were prepared by vertically cutting the embedded sample with a diamond knife.
Then, a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) was used to measure the mass-based detection amount of sulfur atoms in the positive A layer and the oriented layer of the measurement sample. Based on the measurement results, the average detection amount of atoms X in the alignment layer (positive C layer) when the average detection amount of sulfur atoms in the positive A layer is standardized to 100 on a mass basis is calculated, and 20 atoms are calculated. The average value of the sample of was calculated. The results are shown in Table 1.
Further, based on the above measurement results, the "coefficient of variation of condition 1" and the "ratio of condition 2" in the main text of the specification were calculated. The results are shown in Table 1.
As the measuring device of SEM-EDX, SEM "SU8000" manufactured by Hitachi High-Technologies Corporation and EDX "XMAX80" manufactured by Oxford Instruments were used. The measurement conditions of the device were set as follows.
<Measurement conditions>
The characteristic X-ray spectrum was acquired by adjusting the irradiation current and the measurement time in an appropriate manner so that the target element could be sufficiently detected in accordance with the acceleration voltage of 30 kV, the focal length of 15 mm, and (sample inclination of 0 degrees). The concentration of each element was calculated by the ZAF correction method (a method of applying atomic number correction Z, absorption correction A, and fluorescence correction F to the relative intensity of each element to obtain the content of each element).

1-2. Adhesion After the intermediates of the optical laminates of Examples and Comparative Examples were stored for 24 hours in an environment of 23 ° C. and a relative humidity of 50%, the orientation layer of the intermediates of the optical laminates of Examples and Comparative Examples (positive). The C layer) and the positive A layer are transferred to the glass with an adhesive layer to form a glass laminate, and a blade is inserted from the orientation layer (positive C layer) side of the glass laminate to form a 100-square grid (vertical 10 squares x). Cross-cut so that the cutting edge reaches the adhesive layer. Two types of cut intervals, 1 mm and 2 mm, were prepared.
Adhesive tape (manufactured by Nichiban Co., Ltd., product name "3M, Scotch peelable tape, CAT.NO.811-3-18)" is applied to the cross-cut surface of the above cross-cut sample. It was pasted and a peeling test was performed in accordance with the cross-cut method specified in JIS K5600-5-6: 1999. The number of peeled eyes was measured for each of the cut intervals of 1 mm and 2 mm with a microscope (manufactured by Keyence). Evaluation was performed with a digital microscope VH5500 (setting magnification 100 times). The results are shown in Table 1. In "0/100", the number of peeled eyes is 0, and the alignment layer (positive C layer) and the positive A layer are used. "100/100" indicates that the adhesion between the two layers is the best, and all the eyes are peeled off, and the adhesion between the alignment layer (positive C layer) and the positive A layer is poor.

1-3. Transfer workability Regarding the optical laminates of Examples and Comparative Examples (the orientation layer (positive C layer) of the intermediate body of the optical laminates of Examples and Comparative Examples and the laminate obtained by transferring the positive A layer to glass), the positive A layer. Whether or not peeling occurred at the interface between the positive C layer and the positive C layer was evaluated with a microscope (Digital Microscope VH5500 manufactured by KEYENCE CORPORATION, set magnification 100 times). Those in which peeling could not be confirmed were designated as "A", and those in which peeling could be confirmed were designated as "C". The results are shown in Table 1.

2. 2. Synthesis of compounds in the oriented layer 2-1. Synthesis of compounds used in Examples (Monomer 1)
4-Hydroxy-4'-hydroxyethoxybiphenyl was synthesized by heating 4,4'-biphenyldiol and 2-chloroethanol under alkaline conditions. This product was reacted with 1,6-dibromohexane under alkaline conditions to synthesize 4- (6-bromohexyloxy) -4'-hydroxyethoxybiphenyl. Then, lithium methacrylate was reacted to synthesize the monomer 1 represented by the following chemical formula (30).

(Monomer 2)
Under basic conditions, cinnamoyl chloride was added to the monomer 1 to synthesize the monomer 2 represented by the following chemical formula (31).

(Polymer 1)
Monomer 1 and Monomer 2 are dissolved in tetrahydrofuran at a molar ratio of 3: 7, AIBN (azobisisobutyronitrile) is added as a reaction initiator, and the mixture is polymerized at 70 ° C. for 24 hours to be photosensitive. Sexual polymer 1 was obtained. This polymer 1 exhibited liquid crystallinity.

2-2. Preparation of Compounds Used in Comparative Examples An alignment film-forming composition containing a polycinnamate-based compound was used as the alignment film of the comparative examples.

3. 3. Synthesis of compound of positive A layer Compound a (compound of chemical formula (5)) containing the following sulfur atom was synthesized according to the description of Production Example 10 of Examples in JP-A-2019-73712.

4. Fabrication of Optical Laminate [Example 1]
The polymer 1 obtained in 2-1 above was dissolved in cyclohexanone, and a photopolymerization initiator (4,4'-bis (diethylamino) benzophenone manufactured by Tokyo Chemical Industry Co., Ltd.) was added to prepare a coating liquid 1 for a positive C layer. .. The content of the photopolymerization initiator in the coating liquid 1 for the positive C layer was 2 parts by weight with respect to 100 parts by mass of the polymer 1.
On the base material (polyethylene terephthalate (PET) film with a thickness of 100 μm, product name “A4100”, Toyobo Co., Ltd.), the coating liquid 1 for the positive C layer was applied to a thickness of 0.6 μm using a Miyaber, and the room temperature ( It was dried at about 25 ° C.). Then, it was heated to 130 ° C. and then cooled to form a positive C layer which is a homeotropically oriented layer. The Re (550) of the positive C layer was 3.2 nm, and the Rth (550) was −73 nm.
Next, the positive C layer is irradiated with linearly polarized ultraviolet rays (ultraviolet rays obtained by imparting linearly polarized light through a Granteller prism to the light of a high-pressure mercury lamp) for 15 seconds, and the photoreaction of the photosensitive group of the polymer 1 is carried out. It proceeded eccentrically.
Next, the following coating liquid 1 for the positive A layer was applied onto the positive C layer so that the thickness after curing was 2 μm, and a film was formed. Then, after drying at 120 ° C. for 60 seconds, an H-bulb manufactured by Fusion Co., Ltd. was used to irradiate ultraviolet rays (unpolarized ultraviolet rays) at an irradiation amount of 400 mJ / cm ² to form a positive A layer, and Example 1 was performed. An intermediate of the optical laminate of No. 1 was obtained. The Re (550) of the positive A layer was 161 nm, and the Rth (550) of the laminated body was -5 nm.
Next, a transparent adhesive layer (manufactured by Panac Co., Ltd., trade name: Panaclean PD-S1, thickness 25 μm) was formed on the glass substrate, and the surface of the optical laminates of Examples and Comparative Examples on the positive A layer side was concerned. It was attached to the transparent adhesive layer. Next, the peelable base material (PET film) was peeled off to obtain an optical laminate of Example 1 having a glass base material, a transparent pressure-sensitive adhesive layer, a positive A layer, and a positive C layer in this order. The optical laminate had Re (450) of 136 nm, Re (550) of 161 nm, Re (650) of 164 nm, and Rth (550) of −5 nm.

<Coating liquid for positive A layer 1>
-Compound a containing sulfur atom obtained in 3 above 100 parts by mass-Photopolymerization initiator 4 parts by mass (2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one, IGM Resins BV Company, product name "Omnirad 907")
・ Toluene 70 parts by mass ・ Cyclohexanone 30 parts by mass

[Comparative Example 1]
An optical laminate of Comparative Example 1 was obtained in the same manner as in Example 1 except that the coating liquid 1 for the positive C layer was changed to the coating liquid 2 for the positive C layer described below. In the positive C layer of Comparative Example 1, Re (550) was 0.5 nm and Rth (550) was −0.2 nm.

<Coating liquid 2 for positive C layer>
・ Polymerizable liquid crystal compound 4 parts by mass (polycinnamate compound)
-Propylene glycol monomethyl ether 96 parts by mass

From the results of the examples, the optical laminate of the examples is formed by directly laminating the alignment layer and the positive A layer, which can contribute to the thinning, and the alignment layer and the positive A layer are in close contact with each other. It can be confirmed that it is excellent in sex.

10: Base material 20: Orientation layer 30: Positive A layer 50: Polarizer 61: Transparent protective plate A
62: Protective protection plate B
100: Optical laminate 200: Polarizing plate 300: Display element 500: Display panel

Claims (12)

An optical laminate having an oriented layer and a positive A layer.
The oriented layer and the positive A layer are in contact with each other.
The positive A layer contains compound a and contains
The alignment layer contains the compound a transitioned from the positive A layer and other compounds.
The compound a contains an atom X that is substantially free of the other compounds.
An optical laminate in which the average detected amount of the atom X in the oriented layer is 23 or more when the average detected amount of the atom X in the positive A layer is standardized to 100 on a mass basis. The optical laminate according to claim 1, wherein the amount of the atom X detected in the alignment layer satisfies the following condition 1.
(Condition 1)
The amount of the atom X in the alignment layer is detected at 100 points every 26 nm in the direction parallel to the interface at a position of 200 nm in the thickness direction from the interface between the alignment layer and the positive A layer. The coefficient of variation based on the mass of the detected amount of the atom X at the 100 locations is 0.16 or more. The optical laminate according to claim 1 or 2, wherein the amount of the atom X detected in the positive A layer and the alignment layer satisfies the following condition 2.
(Condition 2)
The amount of the atom X in the positive A layer is detected at 100 points every 26 nm in the direction parallel to the interface at a position of 200 nm in the thickness direction from the interface between the positive A layer and the oriented layer. The coefficient of variation based on the mass of the detected atom X is defined as CV1.
The amount of the atom X in the alignment layer is detected at 100 points every 26 nm in the direction parallel to the interface at a position of 200 nm in the thickness direction from the interface between the alignment layer and the positive A layer. The coefficient of variation based on the mass of the detected atom X is defined as CV2.
The ratio of the CV1 to the CV2 (CV2 / CV1) is 2.00 or more. The optical laminate according to any one of claims 1 to 3, wherein the atom X is a sulfur atom. The optical laminate according to any one of claims 1 to 4, wherein the compound a is a polymerizable liquid crystal compound containing a sulfur atom as the atom X. The optical laminate according to any one of claims 1 to 5, wherein the alignment layer is a positive C layer. The optical laminate according to any one of claims 1 to 6, wherein the other compound contains a liquid crystal compound having a photosensitive group. The optical laminate according to claim 1 to 7, wherein the Rht (550) is -100 nm to -50 nm when the phase difference in the thickness direction of the alignment layer at a wavelength of 550 nm is defined as Rht (550). The in-plane phase difference of the optical laminate at a wavelength of 450 nm is Re (450), the in-plane phase difference of the optical laminate at a wavelength of 550 nm is Re (550), and the in-plane phase difference of the optical laminate at a wavelength of 650 nm is Re. The optical laminate according to any one of claims 1 to 8, which satisfies the relationship of the following formula (A) when defined as (650).
Re (450) <Re (550) <Re (650) (A) A polarizing plate having a polarizing element, a transparent protective plate A arranged on one side of the polarizing element, and a transparent protective plate B arranged on the other side of the polarizing element, wherein the transparent protective plate is provided. A polarizing plate in which either the plate A or the transparent protective plate B is the optical laminate according to any one of claims 1 to 9. A display panel comprising the optical laminate according to any one of claims 1 to 9 arranged on a light emitting surface of a display element. An image display device comprising the display panel according to claim 11.

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