JP6193192B2 - Polarizing plate, manufacturing method of polarizing plate, and liquid crystal display device - Google Patents

Description

  The present invention relates to a polarizing plate, a method for manufacturing a polarizing plate, and a liquid crystal display device.

In recent years, liquid crystal display devices have been widely used as image display devices. In a liquid crystal display device, since light is controlled by using a phase difference, an optical compensation film having an optically anisotropic layer formed from a liquid crystal compound on an alignment film is used for high-quality image display. ing.
As an alignment film having a function of uniformly aligning rod-like liquid crystalline molecules so as to be substantially orthogonal to the rubbing direction, for example, Patent Document 1 includes polyimide or polyamic acid, and polyimide or polyamic acid is A liquid crystal alignment film having a carbazole skeleton in the side chain is described.

  On the other hand, Patent Document 2 discloses a circularly polarizing plate having an optical laminated body and a polarizing film, the optical laminated body comprising a transparent support, an optically anisotropic layer A, and an optically anisotropic layer B. In this order, the optically anisotropic layer A is formed from a composition containing a discotic liquid crystal compound having a polymerizable group, and the optically anisotropic layer B contains a rod-like liquid crystal compound having a polymerizable group A circularly polarizing plate formed from the composition is described. Patent Document 2 describes that an alignment film is formed on a support and the optically anisotropic layer A is formed on the alignment film. Moreover, the polarizing plate described in Patent Document 2 is a circularly polarizing plate and does not have rod-like liquid crystalline molecules aligned in a direction perpendicular to the rubbing direction.

JP 2002-268068 A International Publication WO2014 / 054769 Pamphlet

Optical compensation capable of uniformly aligning rod-like liquid crystalline molecules substantially perpendicular to the rubbing direction by using polyimide or polyamic acid having a carbazole skeleton in the side chain described in Patent Document 1 for the liquid crystal alignment film A film can be made. However, in recent years, there has been a demand for further improvement in panel contrast when used in a liquid crystal display device.
The present invention has been made in view of such circumstances, and is a polarizing plate in which a rod-like liquid crystal compound is oriented in a direction perpendicular to the rubbing direction, and has good panel contrast when used in a liquid crystal display device. It was made into the problem which should be solved to provide the polarizing plate which is these, and its manufacturing method. Another object of the present invention is to provide a liquid crystal display device using the polarizing plate.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have aligned the discotic liquid crystal compound perpendicularly to the polarizer surface when forming a layer formed of the discotic liquid crystal compound on the polarizer. And providing a polarizing plate that solves the above problems by causing the slow axis of the alignment layer to be orthogonal to the absorption axis direction of the polarizer, thereby allowing the layer formed from the discotic liquid crystal compound to function as the alignment layer. Succeeded in doing. That is, according to the present invention, the following inventions are provided.

(1) A polarizer, an alignment layer on the surface of the polarizer, and an optically anisotropic layer on the surface of the alignment layer, wherein the alignment layer is formed of a discotic liquid crystal compound, and the discotic The liquid crystal compound is vertically aligned with respect to the polarizer surface, the slow axis of the alignment layer is orthogonal to the absorption axis direction of the polarizer, and the optically anisotropic layer is formed from a rod-like liquid crystal compound. A polarizing plate, wherein the slow axis of the optically anisotropic layer is orthogonal to the absorption axis direction of the polarizer.
(2) The polarizing plate as described in (1) whose film thickness of the said orientation layer is 0.5 micrometer or less.
(3) The polarizing plate according to (1) or (2), wherein the polarizer contains a dichroic dye.
(4) The polarizing plate according to any one of (1) to (3), wherein the retardation Re in the in-plane direction at a wavelength of 550 nm of the optically anisotropic layer is 100 to 180 nm.
(5) The polarizing plate according to any one of (1) to (4), wherein the retardation Rth in the thickness direction at a wavelength of 550 nm of the optically anisotropic layer is 50 to 90 nm.
(6) The polarizing plate according to any one of (1) to (5), wherein the in-plane retardation Re450 at a wavelength of 450 nm and the in-plane retardation Re550 at a wavelength of 550 nm of the optically anisotropic layer satisfy the following formula 1.
Formula 1: 0.70 ≦ Re450 / Re550 ≦ 0.95
(7) The polarizing plate according to any one of (1) to (6), wherein the rod-like liquid crystal compound is a nematic liquid crystal compound and / or a smectic liquid crystal compound.
(8) The second optical anisotropy formed from the rod-like liquid crystal compound on the optically anisotropic layer, wherein the rod-like liquid crystal compound is horizontally aligned with respect to the polarizer surface in the optically anisotropic layer. The polarizing plate according to any one of (1) to (7), further including a conductive layer, wherein the rod-like liquid crystal compound is vertically aligned with respect to the polarizer surface in the second optically anisotropic layer.
(9) The polarizing plate according to (8), wherein the optically anisotropic layer on the surface of the alignment layer satisfies nx> ny = nz, and the second optically anisotropic layer satisfies nz> nx = ny.
However, nx represents the refractive index in the slow axis direction in the optically anisotropic layer surface, ny represents the refractive index in the direction orthogonal to nx in the optically anisotropic layer surface, and nz is the direction orthogonal to nx and ny. Represents the refractive index.
(10) The polarizing plate according to any one of (1) to (9), having a polarizing plate protective film on the surface opposite to the alignment layer on the polarizer.
(11) A polarizing plate protective film, a polarizer on the surface of the polarizing plate protective film, an alignment layer on the surface of the polarizer, a first optical anisotropic layer on the surface of the alignment layer, and the first A polarizing plate having a second optically anisotropic layer on the optically anisotropic layer,
The first optical anisotropic layer satisfies nx> ny = nz, the second optical anisotropic layer satisfies nz> nx = ny,
The alignment layer is formed of a discotic liquid crystal compound, and the discotic liquid crystal compound is vertically aligned with respect to the polarizer plane, and the slow axis of the alignment layer is orthogonal to the absorption axis direction of the polarizer. And
The first optically anisotropic layer is formed of a rod-like liquid crystal compound, and the slow axis of the first optically anisotropic layer is orthogonal to the absorption axis direction of the polarizer;
However, nx represents the refractive index in the slow axis direction in the optically anisotropic layer surface, ny represents the refractive index in the direction orthogonal to nx in the optically anisotropic layer surface, and nz is the direction orthogonal to nx and ny. Represents the refractive index.
(12) rubbing the surface of the polarizer;
Applying a composition containing a discotic liquid crystal compound on the surface of the rubbed polarizer to form an alignment layer;
The method for producing a polarizing plate according to any one of (1) to (11), comprising a step of forming an optically anisotropic layer by applying a composition containing a rod-like liquid crystal compound to the surface of the alignment layer.
(13) A liquid crystal display device comprising the polarizing plate according to any one of (1) to (11).
(14) The liquid crystal display device according to (13), which is in an IPS mode.

  ADVANTAGE OF THE INVENTION According to this invention, when used for a liquid crystal display device, the polarizing plate with favorable panel contrast and its manufacturing method are provided. The liquid crystal display device of the present invention has good panel contrast.

FIG. 1 shows an example of the configuration of the polarizing plate of the present invention.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value. Further, “vertical” and “orthogonal” in terms of angles mean a range of 90 ° ± 10 °.
In the present specification, Re (λ) and Rth (λ) represent in-plane retardation (nm) and retardation in the thickness direction (nm) at wavelength λ, respectively. Note that the wavelength λ is 550 nm unless otherwise specified in this specification. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR or KOBRA CCD series (manufactured by Oji Scientific Instruments).
When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.
Rth (λ) is the above-mentioned Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or WR or KOBRA CCD series) as the tilt axis (rotary axis) (if there is no slow axis, film A total of 6 points of light of wavelength λ nm are incident from the inclined direction in 10 degree steps from the normal direction to 50 degrees on one side with respect to the film normal direction (with any direction in the plane as the rotation axis). KOBRA 21ADH or WR or KOBRA CCD series is calculated based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value.
In the above, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, the retardation value at a tilt angle larger than the tilt angle is After changing the sign to negative, KOBRA 21ADH or WR or KOBRA CCD series calculates. In selecting the measurement wavelength λnm, the wavelength selection filter can be exchanged manually, or the measurement value can be converted by a program or the like.
Note that the retardation value is measured from two inclined directions with the slow axis as the tilt axis (rotary axis) (in the case where there is no slow axis, the arbitrary direction in the film plane is the rotary axis), Rth can also be calculated from the following formula (X) and formula (XI) based on the value, the assumed value of the average refractive index, and the input film thickness value.

上記のＲｅ（θ）は法線方向から角度θ傾斜した方向におけるレタデーション値を表す。また、式中、ｎｘは面内における遅相軸方向の屈折率を表し、ｎｙは面内においてｎｘに直交する方向の屈折率を表し、ｎｚはｎｘ及びｎｙに直交する方向の屈折率を表す。ｄは膜厚を表す。

The above Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction. In the formula, nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction orthogonal to nx in the plane, and nz represents the refractive index in the direction orthogonal to nx and ny. . d represents a film thickness.

In the case where the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film having no so-called optical axis, Rth (λ) is calculated by the following method.
Rth (λ) is −50 degrees with respect to the normal direction of the film, with Re (λ) being the in-plane slow axis (determined by KOBRA 21ADH or WR or KOBRA CCD series) as the tilt axis (rotation axis). From 10 degrees to +50 degrees with light of wavelength λ nm incident from each inclined direction and measured 11 points, and based on the measured retardation value, the assumed average refractive index and the input film thickness value Calculated by KOBRA 21ADH or WR or KOBRA CCD series.
In the above measurement, the assumed value of the average refractive index may be a value in a polymer handbook (John Wiley & Sons, Inc.) or a catalog of various optical films. Those whose average refractive index is not known can be measured with an Abbe refractometer. Examples of the average refractive index values of main optical films are given below:
Cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).
By inputting these assumed values of average refractive index and film thickness, the KOBRA 21ADH or WR or KOBRA CCD series calculates nx, ny, and nz. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

  In the present invention, the “slow axis” of the retardation film or the like means a direction in which the refractive index is maximized. Further, the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified.

<Polarizing plate>
The polarizing plate of the present invention has a polarizer, an alignment layer on the surface of the polarizer, and an optically anisotropic layer on the surface of the alignment layer.
In the present invention, the discotic liquid crystal compound is vertically aligned with respect to the polarizer surface, the slow axis of the alignment layer is orthogonal to the absorption axis direction of the polarizer, and the retardation of the optically anisotropic layer is When the phase axis is orthogonal to the absorption axis direction of the polarizer, the panel contrast of the liquid crystal display device can be improved.

In the present invention, by using a discotic liquid crystal compound for the alignment layer, the uniformity of the alignment layer and the alignment regulating force can be improved. In the present invention, the polarizer surface is rubbed so that the polarizer has an alignment function, so that the discotic liquid crystal compound is aligned perpendicular to the polarizer surface, and the slow axis of the alignment layer is polarized. It is made to be orthogonal to the absorption axis direction of the child. Thereby, a manufacturing process can be simplified and a polarizing plate can also be made thin.
The liquid crystal alignment film described in the above-mentioned Patent Document 1 uses polyimide or polyamic acid having a carbazole skeleton in the side chain, that is, does not use a discotic liquid crystal compound for the alignment layer. It is different from the board. In Patent Document 2, an alignment film is formed on a support, and the optically anisotropic layer A and the optically anisotropic layer B are formed on the alignment film, and the circularly polarized light described in Patent Document 2 The plate is different from the polarizing plate of the present invention in that the slow axis of the alignment layer and the slow axis of the optically anisotropic layer are not orthogonal to the absorption axis of the polarizer.

<< Polarizer >>
The polarizer which the polarizing plate of this invention has is not specifically limited if it is a member which has a function which converts light into specific linearly polarized light, A conventionally well-known absorption type polarizer and reflection type polarizer can be utilized. .
As the absorbing polarizer, an iodine-based polarizer, a dye-based polarizer using a dichroic dye, a polyene-based polarizer, or the like is used, and preferably includes a dichroic dye. Iodine polarizers and dye polarizers include coating polarizers and stretchable polarizers, both of which can be applied, but can be prepared by adsorbing iodine or dichroic dyes to polyvinyl alcohol and stretching. preferable.

Further, as a method for obtaining a polarizer by stretching and dyeing in the state of a laminated film in which a polyvinyl alcohol layer is formed on a substrate, Patent No. 5048120, Patent No. 5143918, Patent No. 4691205, Patent No. 4751481 and Japanese Patent No. 4751486 can be cited, and known techniques relating to these polarizers can also be preferably used.
As the reflective polarizer, a polarizer in which thin films having different birefringence are stacked, a wire grid polarizer, a polarizer in which a cholesteric liquid crystal having a selective reflection region and a quarter wavelength plate are combined, or the like is used.
Among them, a polyvinyl alcohol resin (a polymer containing —CH ₂ —CHOH— as a repeating unit, particularly selected from the group consisting of polyvinyl alcohol and an ethylene-vinyl alcohol copolymer in terms of better adhesion to the resin layer. It is preferable that the polarizer includes at least one of the above.
The thickness of the polarizer is preferably 30 μm or less, more preferably 3 to 25 μm, and even more preferably 4 to 25 μm. If it is the said thickness, it can be used conveniently also when a liquid crystal display device is reduced in thickness.

<< Orientation layer >>
The alignment layer is formed from a discotic liquid crystal compound. The discotic liquid crystal compound is vertically aligned with respect to the polarizer plane. Note that the surface of the alignment layer is preferably not rubbed.
In the case of a discotic liquid crystal compound, the vertical alignment means that the angle formed by the film surface and the disc surface of the discotic liquid crystal compound is within a range of 70 ° to 90 °. The discotic liquid crystal compound may be aligned obliquely. Even in the case of oblique orientation, the average inclination angle is preferably 70 ° to 90 °, more preferably 75 ° to 90 °, and most preferably 80 ° to 90 °. Whether the discotic liquid crystal compound is vertically aligned with respect to the polarizer surface can be confirmed by measuring a tilt angle, which will be described later.
Further, the slow axis of the alignment layer is orthogonal to the absorption axis direction of the polarizer.

(Measure tilt angle of discotic liquid crystal layer)
In the discotic liquid crystal layer in which the discotic liquid crystal compound is aligned, a tilt angle θ1 on one surface (an angle formed by the disc surface of the discotic liquid crystal compound being an interface) θ1 and a tilt angle θ2 on the other surface are It is difficult to measure directly and accurately. Therefore, in this specification, θ1 and θ2 are calculated by the following method. Although this method does not accurately represent the actual orientation state of the present invention, it is effective as a means for expressing the relative relationship of some optical properties of the optical film.
In this method, the following two points are assumed and the tilt angle at the two interfaces of the discotic liquid crystal layer is assumed for easy calculation.
1. The discotic liquid crystal layer is assumed to be a multilayer body composed of layers containing a discotic liquid crystal compound. Further, it is assumed that the minimum unit layer (assuming that the tilt angle of the discotic liquid crystal compound is uniform in this layer) is optically uniaxial.
2. It is assumed that the tilt angle of each layer changes monotonically with a linear function along the thickness direction of the discotic liquid crystal layer.
The specific calculation method is as follows.
(1) Three or more measurement angles are obtained by changing the incident angle of the measurement light to the discotic liquid crystal layer in a plane in which the tilt angle of each layer changes monotonically with a linear function along the thickness direction of the discotic liquid crystal layer. Measure the retardation value with. In order to simplify measurement and calculation, it is preferable to measure the retardation value at three measurement angles of −40 °, 0 °, and + 40 °, with the normal direction to the discotic liquid crystal layer being 0 °. Such measurement includes KOBRA 21ADH or WR or KOBRA CCD series (manufactured by Oji Scientific Instruments), transmission-type ellipsometer AEP-100 (manufactured by Shimadzu Corporation), M150 and M520 (manufactured by JASCO Corporation). ), ABR10A (manufactured by UNIOPT Co., Ltd.).
(2) In the above model, the refractive index of ordinary light in each layer is no, the refractive index of extraordinary light is ne (ne is the same value in all layers, and no is the same), and the thickness of the entire multilayer body is d. And Furthermore, based on the assumption that the tilt direction in each layer and the uniaxial optical axis direction of that layer coincide, the discotic liquid crystal layer is calculated so that the calculation of the angular dependence of the retardation value of the discotic liquid crystal layer matches the measured value. Fitting is performed using the tilt angle θ1 on one surface of the layer and the tilt angle θ2 on the other surface as variables, and θ1 and θ2 are calculated.
Here, known values such as literature values and catalog values can be used for no and ne. If the value is unknown, it can also be measured using an Abbe refractometer. The thickness of the discotic liquid crystal layer can be measured by an optical interference film thickness meter, a cross-sectional photograph of a scanning electron microscope, or the like.

The thickness of the alignment layer is preferably 1.0 μm or less, and more preferably 0.5 μm or less. By setting it as such a structure, a polarizing plate can be made thinner. The lower limit value of the thickness of the alignment layer is not particularly defined, but can be 20 nm or more.
The Re550 of the alignment layer is preferably 2 to 50 nm, more preferably 2 to 30 nm, and most preferably 2 to 20 nm.
Rth550 of the alignment layer is preferably −25 to −1 nm, more preferably −15 to −1 nm, and most preferably −10 to −1 nm.
The alignment layer can be formed from a composition containing a discotic liquid crystal compound. If desired, the composition containing a discotic liquid crystal compound may contain one or more selected from a vertical alignment agent, a fluorine-containing compound, a polymerization initiator, and a polymerizable monomer. A method for manufacturing the alignment layer will be described later.

<<< Discotic Liquid Crystal Compound >>>
Only one type of discotic liquid crystal compound may be used, or two or more types may be used in combination.
As the discotic liquid crystal compound, compounds described in Paragraph Nos. 0037 to 0085 of International Publication WO2014 / 054769 can be used. The polymerization of the discotic liquid crystal compound is described in JP-A-8-27284.

The discotic liquid crystal compound preferably has a polymerizable group so that it can be fixed by polymerization. The discotic liquid crystal compound having a polymerizable group is preferably a compound represented by the following formula.
D (-LP) _n
In the formula, D is a discotic core, L is a divalent linking group, P is a polymerizable group, and n is an integer of 1 to 12. Preferred specific examples of the discotic core (D), the divalent linking group (L) and the polymerizable group (P) in the formula are (D1) to (D15) described in JP-A No. 2001-4837, respectively. , (L1) to (L25), (P1) to (P18), and the contents described in the publication can be preferably used. The discotic nematic liquid crystal phase-solid phase transition temperature of the liquid crystal compound is preferably 30 to 300 ° C, more preferably 30 to 170 ° C.

A discotic liquid crystal compound represented by the following general formula (I) is preferable because it can achieve vertical alignment with high average tilt angle and excellent uniformity.

In the formula, Y ¹¹ , Y ¹² and Y ¹³ each independently represent a methine group or a nitrogen atom which may be substituted.
When Y ¹¹ , Y ¹² and Y ¹³ are methine, the hydrogen atom of methine may be replaced with a substituent. Examples of the substituent that methine may have include an alkyl group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an alkylthio group, an arylthio group, a halogen atom, and A cyano group can be mentioned as a preferred example. Among these substituents, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acyloxy group having 2 to 12 carbon atoms, a halogen atom, and a cyano group are more preferable. preferable.

L ¹ , L ² and L ³ each independently represents a single bond or a divalent linking group.
When L ¹ , L ² and L ³ are divalent linking groups, each independently represents —O—, —S—, —C (═O) —, —NR ⁷ —, —CH═CH—, —C. It is preferably a bivalent linking group selected from the group consisting of ≡C—, a divalent cyclic group, and combinations thereof. R ⁷ is an alkyl group having 1 to ⁷ carbon atoms or a hydrogen atom.

The divalent cyclic group in L ¹ , L ² and L ³ is a divalent linking group having at least one cyclic structure (hereinafter sometimes referred to as a cyclic group). The cyclic group is preferably a 5-membered ring, a 6-membered ring, or a 7-membered ring. The ring contained in the cyclic group may be a condensed ring or a single ring. The ring contained in the cyclic group may be any of an aromatic ring, an aliphatic ring, and a heterocyclic ring. As the aromatic ring, a benzene ring and a naphthalene ring are preferable. As the aliphatic ring, a cyclohexane ring is preferable. As the heterocyclic ring, a pyridine ring and a pyrimidine ring are preferable.
The divalent cyclic group represented by L ¹ , L ² and L ³ may have a substituent. Examples of the substituent include a halogen atom (preferably a fluorine atom and a chlorine atom), a cyano group, a nitro group, an alkyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, and 2 to 2 carbon atoms. 16 alkynyl group, halogen-substituted alkyl group having 1 to 16 carbon atoms, alkoxy group having 1 to 16 carbon atoms, acyl group having 2 to 16 carbon atoms, alkylthio group having 1 to 16 carbon atoms, 2 carbon atoms ˜16 acyloxy groups, C2-C16 alkoxycarbonyl groups, carbamoyl groups, carbamoyl groups substituted with C2-C16 alkyl groups and C2-C16 acylamino groups are included.

L ¹ , L ² and L ³ include a single bond, * —O—CO—, * —CO—O—, * —CH═CH—, * —C≡C—, * —divalent cyclic group— * -O-CO-divalent cyclic group-, * -CO-O-divalent cyclic group-, * -CH = CH-divalent cyclic group-, * -C≡C-divalent cyclic group Group-, * -divalent cyclic group-O-CO-, * -divalent cyclic group-CO-O-, * -divalent cyclic group-CH = CH- and * -divalent cyclic group- C≡C— is preferred. Here, * represents the position bonded to the 6-membered ring side including Y ¹¹ , Y ¹² and Y ¹³ in the general formula (I).

In the general formula ^{(I), H 1, H} 2 and H ³ represent each group independently formula (I-A) or (IB).

In general formula (IA), YA ¹ and YA ² each independently represents a methine or nitrogen atom which may have a substituent; XA represents an oxygen atom, a sulfur atom, methylene or imino; Represents a position bonded to the L ^{1 to} L ³ side in the general formula (I); ** represents a position bonded to the R ^{1 to} R ³ side in the general formula (I).

In general formula (IB), YB ¹ and YB ² each independently represent a methine or nitrogen atom which may have a substituent; XB represents an oxygen atom, a sulfur atom, methylene or imino; Represents a position bonded to the L ^{1 to} L ³ side in the general formula (I); ** represents a position bonded to the R ^{1 to} R ³ side in the general formula (I).

In general formula (I), R < ¹ >, R < ² > and R < ³ > represent the following general formula (IR) each independently.
General formula (IR)
*-(-L ²¹ -Q ² ) _n1 -L ²² -L ²³ -Q ¹
In general formula (I-R), * represents a position bonded to the H ^{1 to} H ³ side in general formula (I).
L ²¹ represents a single bond or a divalent linking group. When L ²¹ is a divalent linking group, the group consisting of —O—, —S—, —C (═O) —, —NR ⁸ —, —CH═CH—, —C≡C—, and combinations thereof It is preferably a divalent linking group selected more. R ⁸ is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom.

Q ² represents a divalent group (cyclic group) having at least one kind of cyclic structure. Such a cyclic group is preferably a cyclic group having a 5-membered ring, a 6-membered ring, or a 7-membered ring. The cyclic structure contained in the cyclic group may be a condensed ring or a single ring. The ring contained in the cyclic group may be any of an aromatic ring, an aliphatic ring, and a heterocyclic ring. The aromatic ring is preferably a benzene ring, naphthalene ring, anthracene ring, or phenanthrene ring, the aliphatic ring is preferably a cyclohexane ring, and the heterocyclic ring is preferably a pyridine ring or a pyrimidine ring.
Q ² may have a substituent. Examples of the substituent include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, nitro group, alkyl group having 1 to 16 carbon atoms, alkenyl group having 2 to 16 carbon atoms, carbon An alkynyl group having 2 to 16 atoms, an alkyl group substituted with a halogen having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an acyl group having 2 to 16 carbon atoms, and 1 to 16 carbon atoms An alkylthio group having 2 to 16 carbon atoms, an alkoxycarbonyl group having 2 to 16 carbon atoms, a carbamoyl group, an alkyl-substituted carbamoyl group having 2 to 16 carbon atoms, and an acylamino group having 2 to 16 carbon atoms. included.

n1 represents the integer of 0-4.
L ²² is **-O-, **-O-CO-, **-CO-O-, **-O-CO-O-, **-S-, **-N (R ¹⁰¹ ). -, ** - SO2 -, ** - CH2 -, ** - CH = CH- or ** - C≡C- represents, R ¹⁰¹ represents an alkyl group having 1 to 5 carbon atoms, and ** This represents the position to be coupled to the Q ² side.
When L ²² is a group containing a hydrogen atom, the hydrogen atom may be substituted with a substituent. Examples of such a substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 6 carbon atoms, an alkyl group substituted with a halogen having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms. , An acyl group having 2 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, an acyloxy group having 2 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, a carbamoyl group, and 2 to 2 carbon atoms Preferred are carbamoyl groups substituted with 6 alkyls and acylamino groups having 2 to 6 carbon atoms.

L ²³ represents —O—, —S—, —C (═O) —, —SO ₂ —, —NH—, —CH ₂ —, —CH═CH—, —C≡C— and combinations thereof. Represents a divalent linking group selected from the group consisting of Here, the hydrogen atoms of —NH—, —CH ₂ —, and —CH═CH— may be substituted with a substituent. Such a substituent has the same meaning as the substituent described for L ²² .

L ²³ is preferably selected from the group consisting of —O—, —C (═O) —, —CH ₂ —, —CH═CH—, —C≡C—, and combinations thereof. L ²³ preferably contains 1 to 20 carbon atoms, and L ²³ preferably contains 1 to 16 —CH ₂ —.

Q ¹ represents a polymerizable group or a hydrogen atom. The kind of the polymerizable group is not particularly limited, and a functional group capable of addition polymerization reaction is preferable, and a polymerizable ethylenically unsaturated group or a ring-opening polymerizable group is preferable. More specifically, a (meth) acryloyl group, a vinyl group, a styryl group, an allyl group, etc. are mentioned preferably, and a (meth) acryloyl group is more preferable. Examples of the polymerizable ethylenically unsaturated group include the following formulas (M-1) to (M-6).

In formulas (M-3) and (M-4), R represents a hydrogen atom or an alkyl group, preferably a hydrogen atom or a methyl group.
The ring-opening polymerizable group is preferably a cyclic ether group, and more preferably an epoxy group or an oxetanyl group.

Specific examples of the compound represented by the general formula (I) include, for example, compounds described in paragraphs 0038 to 0069 of JP2009-97002A, but the present invention is not limited thereto.
In addition, the discotic liquid crystal compounds described in paragraphs 0058 to 0077 of Japanese Patent No. 4067665 can also be used.
The content of the discotic liquid crystal compound in the composition for forming the alignment layer is not particularly limited, but is preferably 50% by mass or more, more preferably 50 to 90% by mass with respect to the total solid content, More preferably, it is 60-90 mass%. When two or more kinds of discotic liquid crystal compounds are used, the total amount is preferably within the above range.

<<< Vertical alignment agent >>>
As the vertical alignment agent, a pyridinium derivative (pyridinium salt) represented by the following general formula (II) is preferably used. By adding at least one pyridinium derivative, the molecules of the discotic liquid crystal compound can be aligned substantially vertically.

In the formula, L ²³ and L ²⁴ each represent a divalent linking group.
L ²³ represents a single bond, —O—, —O—CO—, —CO—O—, —C≡C—, —CH═CH—, —CH═N—, —N═CH—, —N═. N-, -O-AL-O-, -O-AL-O-CO-, -O-AL-CO-O-, -CO-O-AL-O-, -CO-O-AL-O- CO-, -CO-O-AL-CO-O-, -O-CO-AL-O-, -O-CO-AL-OCO- or -O-CO-AL-CO-O-. Preferably, AL is an alkylene group having 1 to 10 carbon atoms. L ²³ represents a single bond, —O—, —O—AL—O—, —O—AL—O—CO—, —O—AL—CO—O—, —CO—O—AL—O—, — CO-O-AL-O-CO-, -CO-O-AL-CO-O-, -O-CO-AL-O-, -O-COAL-O-CO- or -O-CO-AL- CO-O- is preferred.

L ²⁴ represents a single bond, —O—, —O—CO—, —CO—O—, —C≡C—, —CH═CH—, —CH═N—, —N═CH— or —N═. N- is preferred. When m is 2 or more, it is more preferable that the plurality of L ²⁴ are alternately —O—CO— and —CO—O—.

R ²² is a hydrogen atom, an unsubstituted amino group, or a substituted amino group having 1 to 25 carbon atoms.
When R ²² is a dialkyl-substituted amino group, two alkyl groups may be bonded to each other to form a nitrogen-containing heterocycle. The nitrogen-containing heterocycle formed at this time is preferably a 5-membered ring or a 6-membered ring. R ²² is more preferably a hydrogen atom, an unsubstituted amino group, or a dialkyl-substituted amino group having 2 to 12 carbon atoms. When R ²² is an unsubstituted amino group or a substituted amino group, the 4-position of the pyridinium ring is preferably substituted.

X is an anion.
X is preferably a monovalent anion. Examples of anions include halogen anions (eg, fluorine ions, chlorine ions, bromine ions, iodine ions, etc.), sulfonate ions (eg, methanesulfonate ion, trifluoromethanesulfonate ion, methylsulfate ion, p-toluenesulfone). Acid ion, p-chlorobenzenesulfonic acid ion, 1,3-benzenedisulfonic acid ion, 1,5-naphthalenedisulfonic acid ion, 2,6-naphthalenedisulfonic acid ion), sulfate ion, carbonate ion, nitrate ion, thiocyanic acid Examples include ions, perchlorate ions, tetrafluoroborate ions, picrate ions, acetate ions, formate ions, trifluoroacetate ions, phosphate ions (for example, hexafluorophosphate ions), and hydroxide ions.

Y ²² and Y ²³ are each a divalent linking group having a 5- or 6-membered ring as a partial structure.
The 5- or 6-membered ring may have a substituent. Preferably, at least one of Y ²² and Y ²³ is a divalent linking group having a 5- or 6-membered ring having a substituent as a partial structure. Y ²² and Y ²³ are preferably each independently a divalent linking group having a 6-membered ring which may have a substituent as a partial structure. The 6-membered ring includes an aliphatic ring, an aromatic ring (benzene ring) and a heterocyclic ring. Examples of the 6-membered aliphatic ring include a cyclohexane ring, a cyclohexene ring, and a cyclohexadiene ring. Examples of 6-membered heterocycles include pyran ring, dioxane ring, dithiane ring, thiine ring, pyridine ring, piperidine ring, oxazine ring, morpholine ring, thiazine ring, pyridazine ring, pyrimidine ring, pyrazine ring, piperazine ring and triazine ring. Including. Another 6-membered ring or 5-membered ring may be condensed to the 6-membered ring.
Examples of the substituent include a halogen atom, cyano, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms. The alkyl group and the alkoxy group may be substituted with an acyl group having 2 to 12 carbon atoms or an acyloxy group having 2 to 12 carbon atoms. The substituent is preferably an alkyl group having 1 to 12 (more preferably 1 to 6, more preferably 1 to 3) carbon atoms. The number of substituents may be 2 or more. For example, when Y ²² and Y ²³ are a phenylene group, the number of carbon atoms of 1 to 4 is 1 to 12 (more preferably 1 to 6, more preferably 1 to The alkyl group of 3) may be substituted.

Here, m is 1 or 2, and is preferably 2. When m is 2, the plurality of Y ²³ and L ²⁴ may be the same as or different from each other.

Z ²¹ is halogen-substituted phenyl, nitro-substituted phenyl, cyano-substituted phenyl, phenyl substituted with an alkyl group having 1 to 25 carbon atoms, phenyl substituted with an alkoxy group having 1 to 25 carbon atoms, carbon atoms An alkyl group having 1 to 25 carbon atoms, an alkynyl group having 2 to 25 carbon atoms, an alkoxy group having 1 to 25 carbon atoms, an alkoxycarbonyl group having 1 to 25 carbon atoms, and 7 to 26 carbon atoms And a monovalent group selected from the group consisting of an arylcarbonyloxy group having 7 to 26 carbon atoms.
When m is 2, Z ²¹ is preferably cyano, an alkyl group having 1 to 25 carbon atoms, or an alkoxy group having 1 to 25 carbon atoms, and is an alkoxy group having 4 to 20 carbon atoms. Is more preferable.
When m is 1, Z ²¹ is an alkyl group having 7 to 25 carbon atoms, an alkoxy group having 7 to 25 carbon atoms, an acyl-substituted alkyl group having 7 to 25 carbon atoms, or 7 carbon atoms. An acyl-substituted alkoxy group having ˜25, an acyloxy-substituted alkyl group having 7 to 12 carbon atoms, or an acyloxy-substituted alkoxy group having 7 to 25 carbon atoms is preferable.

  The acyl group is represented by —CO—R, the acyloxy group is represented by —O—CO—R, and R is an aliphatic group (alkyl group, substituted alkyl group, alkenyl group, substituted alkenyl group, alkynyl group, substituted alkynyl group) or aromatic. Group (aryl group, substituted aryl group). R is preferably an aliphatic group, and more preferably an alkyl group or an alkenyl group.

p is an integer of 1-10. It is particularly preferable that p is 1 or 2. C _p H _2p means a chain alkylene group which may have a branched structure. C _p H _2p is preferably a linear alkylene group (— (CH ₂ ) _p —).

Among the compounds represented by the formula (II), a compound represented by the following formula (IIA) is preferable.

In formula (IIA), the same symbols as in formula (II) have the same significance.
L ²⁵ is synonymous with L ²⁴ . L ²⁴ and L ²⁵ are preferably —O—CO— or —CO—O—, L ²⁴ is preferably —O—CO—, and L ²⁵ is preferably —CO—O—.
R ²³ , R ²⁴ and R ²⁵ are each an alkyl group having 1 to 12 carbon atoms (more preferably 1 to 6, more preferably 1 to 3). n23 represents 0 to 4, n24 represents 1 to 4, and n25 represents 0 to 4. It is preferable that n23 and n25 are 0 and n24 is 1 to 4 (more preferably 1 to 3).
Specific examples of the compound represented by the general formula (II) include compounds described in paragraphs 0058 to 0061 of JP-A-2006-113500, for example.

（一般式（ＩＩＩ）中、Ｒ¹及びＲ²はそれぞれ独立に、水素原子、置換もしくは無置換の、脂肪族炭化水素基、アリール基又はヘテロ環基を表し、これらは互いに連結して環を形成してもよい。Ｒ³は置換もしくは無置換の、脂肪族炭化水素基、アリール基又はヘテロ環基を表す。）
一般式（ＩＩＩ）中、Ｒ¹及びＲ²はそれぞれ独立に、水素原子、置換もしくは無置換の、脂肪族炭化水素基、アリール基、またはヘテロ環基を表す。脂肪族炭化水素基としては、炭素数１〜２０の置換もしくは無置換の直鎖もしくは分岐のアルキル基（例えば、メチル基、エチル基、ｉｓｏ−プロピル基等）、炭素数３〜２０の置換もしくは無置換の環状アルキル基（例えば、シクロヘキシル基等）、炭素数２〜２０のアルケニル基（例えば、ビニル基等）が挙げられ、アリール基としては、炭素数６〜２０の置換もしくは無置換のフェニル基（例えば、フェニル基、トリル基など）、炭素数１０〜２０の置換もしくは無置換のナフチル基等が挙げられ、ヘテロ環基としては例えば、少なくとも一つのヘテロ原子（例えば、窒素原子、酸素原子、硫黄原子等）を含む、置換もしくは無置換の５員もしくは６員環の基であり、例えば、ピリジル基、イミダゾリル基、フリル基、ピペリジル基、モルホリノ基等が挙げられる。これらは互いに連結して環を形成しても良く、例えば、Ｒ¹及びＲ²のイソプロピル基が連結して、４，４，５，５−テトラメチル−１，３，２−ジオキサボロラン環を形成しても良い。 The following boronic acid compounds can also be used as the vertical alignment agent. The boronic acid compound is preferably represented by the following general formula (III).

(In the general formula (III), R ¹ and R ² each independently represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, an aryl group or a heterocyclic group, which are connected to each other to form a ring. R ³ represents a substituted or unsubstituted aliphatic hydrocarbon group, aryl group or heterocyclic group.
In general formula (III), R ¹ and R ² each independently represent a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, an aryl group, or a heterocyclic group. Examples of the aliphatic hydrocarbon group include a substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms (for example, a methyl group, an ethyl group, an iso-propyl group, etc.), Examples thereof include an unsubstituted cyclic alkyl group (for example, cyclohexyl group) and an alkenyl group having 2 to 20 carbon atoms (for example, a vinyl group). As the aryl group, substituted or unsubstituted phenyl having 6 to 20 carbon atoms. A group (for example, phenyl group, tolyl group, etc.), a substituted or unsubstituted naphthyl group having 10 to 20 carbon atoms, and the like. Examples of the heterocyclic group include at least one hetero atom (for example, nitrogen atom, oxygen atom). A substituted or unsubstituted 5- or 6-membered ring group containing, for example, a pyridyl group, an imidazolyl group, a furyl group, a piperidyl group, Ruhorino group, and the like. These may be connected to each other to form a ring. For example, the isopropyl groups of R ¹ and R ² are connected to form a 4,4,5,5-tetramethyl-1,3,2-dioxaborolane ring. You may do it.

In general formula (III), R ³ represents a substituted or unsubstituted aliphatic hydrocarbon group, aryl group or heterocyclic group. Examples of the aliphatic hydrocarbon group include a substituted or unsubstituted linear or branched alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cyclic alkyl group having 3 to 20 carbon atoms, and an alkenyl group having 2 to 20 carbon atoms. Examples of the aryl group include substituted or unsubstituted phenyl groups having 6 to 50 carbon atoms (for example, phenyl group, tolyl group, styryl group, 4-benzoyloxyphenyl group, 4-phenoxycarbonylphenyl group, 4- Biphenyl group, 4- (4-octyloxybenzoyloxy) phenoxycarbonylphenyl group, etc.), substituted or unsubstituted naphthyl group having 10 to 50 carbon atoms (for example, unsubstituted naphthyl group, etc.), and heterocyclic group For example, substituted or non-substituted containing at least one hetero atom (for example, nitrogen atom, oxygen atom, sulfur atom, etc.) Substituted or 5-membered groups such as pyrrole, furan, thiophene, pyrazole, imidazole, triazole, oxazole, isoxazole, oxadiazole, thiazole, thiadiazole, indole, carbazole, benzofuran, dibenzofuran, thianaphthene, Dibenzothiophene, indazolebenzimidazole, anthranyl, benzisoxazole, benzoxazole, benzothiazole, purine, pyridine, pyridazine, pyrimidine, pyrazine, triazine, quinoline, acridine, isoquinoline, phthalazine, quinazoline, quinoxaline, naphthyridine, phenanthroline, pteridine, morpholine And groups such as piperidine. Furthermore, one or more of these aliphatic hydrocarbon groups, aryl groups, and heterocyclic groups included in the heterocyclic group may be substituted with any substituent.
Details and preferred ranges of the boronic acid compound represented by the general formula (III) are described in paragraph numbers 0016 to 0023 of JP-A No. 2014-129255, and the contents thereof are cited in the present specification. Specific examples of the boronic acid compound include compounds described in paragraph numbers 0026 to 0029 of JP2014-129255A.

  Although content of the vertical alignment agent in the composition for forming an alignment layer is not specifically limited, Preferably it is 1-20 mass% with respect to the total solid, More preferably, it is 1-10 mass%. When two or more kinds of vertical alignment agents are used, the total amount is preferably within the above range.

<<< Fluorine-containing compound >>>
A fluorine-containing compound may be added to the alignment layer.
As the fluorine-containing compound, a polymer of a repeating unit (polymerization unit) corresponding to the monomer (i) below, or a repeating unit (polymerization unit) corresponding to the monomer (i) below and a monomer of the following (ii) And an acrylic resin, a methacrylic resin containing a repeating unit (polymerization unit), and a copolymer with a vinyl monomer copolymerizable therewith. Examples of such monomers include Polymer Handbook 2nd ed. , J .; Brandrup, Wiley Interscience (1975) Chapter 2, Pages 1-483 can be used. For example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. I can give you.

(I) Fluoroaliphatic group-containing monomer represented by the following general formula IV

In the general formula IV, R ¹ represents a hydrogen atom, a halogen atom or a methyl group, preferably a hydrogen atom or a methyl group. X represents an oxygen atom, a sulfur atom or —N (R ¹² ) —, more preferably an oxygen atom or —N (R ¹² ) —, and still more preferably an oxygen atom. R ¹² represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and still more preferably a hydrogen atom or a methyl group. R _f represents —CF ₃ or —CF ₂ H.
M in the general formula IV represents an integer of 1 to 6, more preferably 1 to 3, and still more preferably 1.
N in general formula IV represents the integer of 1-11, 1-9 are more preferable, and 1-6 are still more preferable. R _f is preferably —CF ₂ H.
Two or more kinds of polymer units derived from the fluoroaliphatic group-containing monomer represented by the general formula IV may be contained in the fluorine-containing compound as a constituent component.

(Ii) Monomer represented by the following general formula V copolymerizable with the above (i)

In the general formula V, R ¹³ represents a hydrogen atom, a halogen atom or a methyl group, and more preferably a hydrogen atom or a methyl group. Y represents an oxygen atom, a sulfur atom or —N (R ¹⁵ ) —, more preferably an oxygen atom or —N (R ¹⁵ ) —, and still more preferably an oxygen atom. R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and still more preferably a hydrogen atom or a methyl group.
R ¹⁴ represents a linear, branched or cyclic alkyl group having 1 to 60 carbon atoms, an aromatic group (for example, a phenyl group or a naphthyl group), or a combination thereof. The alkyl group may include a poly (alkyleneoxy) group. Furthermore, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms is more preferable, and a linear or branched alkyl group having 1 to 10 carbon atoms is very preferable.

  The amount of the fluoroaliphatic group-containing monomer represented by the general formula IV used for the production of the fluorine-containing compound is 10% by mass to 90% by mass, preferably 15%, based on the total amount of the monomer of the fluorine-containing compound. It is mass%-80 mass%, More preferably, it is the range of 20 mass%-70 mass%.

As the fluorine-containing compound, a fluorine-containing compound that is a fluorine-based polymer containing the formula (VI) as a partial structure, or a fluorine-containing compound represented by the general formula (VII) can also be used.
The fluorine-based polymer containing the formula (VI) as a partial structure is preferably a copolymer containing a repeating unit derived from a fluoroaliphatic group-containing monomer and a repeating unit represented by the following formula (VI).

In the formula, R ¹ , R ² and R ³ each independently represents a hydrogen atom or a substituent; L is a divalent linking group selected from the following linking group group or 2 selected from the following linking group group. It represents a divalent linking group formed by combining two or more.
(Linked group group)
Single bond, —O—, —CO—, —NR ⁴ — (R ⁴ represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group), —S—, —SO ₂ —, —P (═O) (OR ⁵ ) — (R ⁵ represents an alkyl group, an aryl group, or an aralkyl group), an alkylene group, and an arylene group.
Q represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or phosphonoxy {—OP (═O) (OH) ₂ } or a salt thereof.

The fluoropolymer is selected from the group consisting of a fluoroaliphatic group, a carboxyl group (—COOH), a sulfo group (—SO ₃ H), a phosphonoxy group {—OP (═O) (OH) ₂ }, and salts thereof. It is preferable to contain one or more hydrophilic groups. Examples of the polymer include polyolefins, polyesters, polyamides, polyimides, polyurethanes, polycarbonates, polysulfones, polycarbonates, polyethers, polyacetals, polyketones, polyphenylene oxides, and polyphenylene sulfides. , Polyarylates, PTFEs, polyvinylidene fluorides, cellulose derivatives and the like. The fluoropolymer is preferably a polyolefin.

  The fluorine-based polymer is a polymer having a fluoroaliphatic group in the side chain. The fluoroaliphatic group preferably has 1 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms. The aliphatic group may be linear or cyclic, and when it is linear, it may be linear or branched. Of these, a linear fluoroaliphatic group having 6 to 10 carbon atoms is preferable. The degree of substitution with fluorine atoms is not particularly limited, but 50% or more of hydrogen atoms in the aliphatic group are preferably substituted with fluorine atoms, and more preferably 60% or more are substituted. The fluoroaliphatic group is contained in a side chain bonded to the polymer main chain via an ester bond, an amide bond, an imide bond, a urethane bond, a urea bond, an ether bond, a thioether bond, an aromatic ring, or the like.

Specific examples of the fluoroaliphatic group-containing copolymer preferably used as the fluoropolymer include compounds described in paragraphs [0110] to [0114] of JP-A-2006-113500. There is no limitation by example.
The weight average molecular weight of the fluoropolymer is preferably 1,000,000 or less, more preferably 500,000 or less, 100,000 or less, and even more preferably 10,000 or more. By setting it in this range, it is effective for controlling the alignment of the liquid crystal compound while satisfying the solubility. The weight average molecular weight can be measured as a value in terms of polystyrene (PS) using gel permeation chromatography (GPC).

As the fluorine-containing compound, a fluorine-containing compound represented by the following formula (VII) can also be used.
(VII) (R ⁰ ) _m −L ⁰ − (W) _n
In the formula, R ⁰ represents an alkyl group, an alkyl group having a CF ₃ group at the terminal, or an alkyl group having a CF ₂ H group at the terminal, and m represents an integer of 1 or more. A plurality of R ⁰ may be the same or different, but at least one represents an alkyl group having a CF ₃ group or a CF ₂ H group at the terminal. L ⁰ represents a (m + n) -valent linking group, W represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or phosphonoxy {—OP (═O) (OH) ₂ } Or a salt thereof, and n represents an integer of 1 or more.
Specific examples of the fluorine-containing compound represented by the formula (VII) that can be used in the present invention include compounds described in paragraphs 0136 to 0140 of JP-A-2006-113500.

  The content of the fluorine-containing compound in the composition for forming the alignment layer is not particularly limited, but is preferably 0.005 to 8% by mass with respect to the total solid content, and 0.01 to 5% by mass. It is more preferable that it is 0.05 to 3% by mass. When two or more types of fluorine-containing compounds are used, the total amount is preferably within the above range.

<<< Polymerization initiator >>>
In the present invention, in order to fix the alignment state of the discotic liquid crystal compound having a polymerizable group, a polymerization reaction of the polymerizable group introduced into the liquid crystal compound is performed. Therefore, the composition for forming the optically anisotropic layer preferably contains a polymerization initiator. Examples of the polymerization reaction include a thermal polymerization reaction using a thermal polymerization initiator, a photopolymerization reaction using a photopolymerization initiator, or energy electron beam curing using an electron beam, and a photopolymerization reaction is preferable. As the polymerization initiator, it is preferable to use a photopolymerization initiator. As the photopolymerization initiator, a photoradical polymerization initiator and a photocationic polymerization initiator are preferable, and a photoradical polymerization initiator is particularly preferable. Examples of the photo radical polymerization initiator include acetophenones, benzophenones, Michler's benzoylbenzoate, α-amyloxime ester, tetramethylthiuram monosulfide, and thioxanthones.

  As a commercially available radical photopolymerization initiator, Kayacure (registered trademark) manufactured by Nippon Kayaku Co., Ltd. (DETX-S, BP-100, BDKM, CTX, BMS, 2-EAQ, ABQ, CPTX, EPD, ITX, QTX, BTC, MCA, etc.), BASF's Irgacure (819, 651, 184, 127, 500, 907, 369, 1173, 2959, 4265, 4263, etc.), Esacure made by Sartomer (KIP100F, KB1, EB3, BP) X33, KT046, KT37, KIP150, TZT) and the like.

  In particular, photocleavable photoradical polymerization initiators are preferred. The photocleavable photoradical polymerization initiator is described in the latest UV curing technology (P.159, issuer; Kazuhiro Takasawa, publisher; Technical Information Association, published in 1991). Examples of commercially available photocleavable photoradical polymerization initiators include Irgacure (registered trademark) (651, 184, 127, 907) manufactured by Ciba Specialty Chemicals.

  The amount of the photopolymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 10% by mass, based on the solid content of the composition. When two or more kinds of photopolymerization initiators are used, the total amount is preferably within the above range.

<<< Polymerizable monomer >>>
A polymerizable monomer may be used in combination with the above discotic liquid crystal compound. Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Preferably, it is a polyfunctional radically polymerizable monomer and is preferably copolymerizable with the above-described polymerizable group-containing liquid crystal compound. Examples thereof include those described in paragraph numbers [0018] to [0020] in JP-A No. 2002-296423. The amount of the compound added is generally in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass with respect to the liquid crystal compound. When two or more kinds of polymerizable monomers are used, the total amount is preferably within the above range.

<< Optically anisotropic layer >>
The polarizing plate of the present invention has an optically anisotropic layer on the surface of an alignment layer formed from a vertically aligned discotic liquid crystal. The optically anisotropic layer is formed of a rod-like liquid crystal compound, and the major axis direction of the rod-like liquid crystal compound is aligned in a direction parallel to the disc surface of the discotic liquid crystal of the alignment layer. That is, the slow axis of the optically anisotropic layer is orthogonal to the absorption axis direction of the polarizer. In the optically anisotropic layer, the rod-like liquid crystal compound is preferably horizontally aligned with respect to the polarizer surface. Although the thickness of an optically anisotropic layer is not specifically limited, Generally, it is 0.5-30 micrometers, Preferably it is 0.5-20 micrometers, More preferably, it is 1-10 micrometers.
The optically anisotropic layer can be formed from a composition containing a rod-like liquid crystal compound. If desired, additives described later can be added to the composition containing the rod-like liquid crystal compound. A method for producing the optically anisotropic layer will be described later.

<<< Bar-shaped liquid crystal compound >>>
The rod-like liquid crystal compound is preferably a nematic liquid crystal compound or a smectic liquid crystal compound.
As the rod-like liquid crystal compound, it is preferable to use a liquid crystal compound having at least a rigid portion called a mesogenic group and a polymerizable group. When the molecular weight of the rod-like liquid crystal compound is increased, the solubility of the rod-like liquid crystal compound decreases, and it becomes difficult to obtain a desired coating film by solvent coating, and the surface of the optically anisotropic layer can be deteriorated in production suitability. Since the film quality such as properties is poor, the molecular weight of the rod-like liquid crystal compound is desirably 1300 or less.

The rod-like liquid crystal compound is particularly preferably a compound having a structure represented by the following general formula (11).
General formula (11):
_{Q1-SP1-X1-M 1} - (Y1-L-Y2-M 2) n-X2-SP2-Q2
Where
n is an integer of 0 or more indicating the number of repetitions of _(Y1-L-Y2-M 2),
Q1 and Q2 are polymerizable groups,
SP1 and SP2 are each a linear or branched alkylene group, a group comprising a combination of a linear or branched alkylene group and at least one of —O— or —C (═O) —, having 2 to 8 carbon atoms in total. An integer group;
X1 and X2 are a single bond or an oxygen atom;
-Y1-L-Y2- is a linear alkylene group, or a combination thereof with -O- and / or -C (= O)-, and is an integer group having 3 to 18 total carbon atoms. ;
M ₁ represents —Ar ₁ —COO—Ar 2 —COO—Ar 3 —COO—.
Or -Ar1-COO-Ar2-COO-Ar3-
Or -Ar1-COO-Ar2-Ar3-
Or -Ar1-COO-Ar2-OCO-Ar3-
A group represented by:
M ₂ represents —Ar 3 —OCO—Ar ₂ —OCO—Ar 1 —OCO—.
Or -Ar3-OCO-Ar2-OCO-Ar1-
Or -Ar3-OCO-Ar2-Ar1-
A group represented by:
Ar1, Ar2 and Ar3 are independently phenylene or biphenylene which may be substituted with any number of bromine atoms, methyl groups and methoxy groups.

The polymerizable groups Q1 and Q2 are preferably radically polymerizable groups (eg, ethylenically unsaturated groups) or ring-opening polymerizable groups (eg, epoxy groups, oxetane groups), more preferably radically polymerizable groups. preferable.
SP1 and SP2 have a structure called a spacer group that connects a polymerizable group and a mesogenic group.
The spacer group is preferably an alkylene group having 2 to 12 carbon atoms, an alkylene oxide,
Alkylene oxide is more preferred.
The alkylene oxide is preferably ethylene oxide, and a structure containing 2 to 3 units is particularly preferred because the temperature range of the liquid crystal phase can be controlled widely. X1 and X2 represent a linking group and are selected from a single bond or an oxygen atom.

n represents an integer of 0 or more. When n increases, liquid crystal molecules having already polymerized mesogenic groups are produced, so that polymerization shrinkage during the formation of the optically anisotropic layer can be reduced.
However, since the smectic liquid crystal has strong interaction between molecules, if n is increased, the viscosity increases, and high temperature and long time are required for the alignment. Therefore, n is preferably 0 to 3, more preferably 0 to 2, 0 to 1 is particularly preferable.

  Ar1, Ar2, Ar3 are each independently phenylene or biphenylene optionally substituted with any number of bromine atoms, methyl groups, and methoxy groups. The total number of benzene rings contained in Ar1, Ar2, Ar3 is 3-6. Is more preferable, it is more preferable that it is 3-5, and it is especially preferable that it is 3-4.

  Specific examples of the polymerizable rod-like liquid crystal compound represented by the general formula (11) are given below, but the present invention is not limited to the following specific examples.

  The compound of the present invention represented by the general formula (11) can be synthesized by combining known synthesis reactions. That is, it can be synthesized with reference to methods described in various documents (for example, Methoden der Organischen Chemie (Houben-Weyl), Some specific methods (Thieme-Verlag, Stuttgart), Experimental Chemistry Course and New Experimental Chemistry Course). As synthesis methods, U.S. Pat. Nos. 4,683,327, 4,983,479, 5,622,648, 5,770,107, International Patents (WO) 95/22586, 97/00600, 98/47979, and British Patent 2297549. The description of each specification of the issue can also be referred to.

The rod-like liquid crystal compound is also preferably a compound composed of the following general formula (12).
_{L 1 -G 1 -D 1 -Ar-} D 2 -G 2 -L 2 Formula (12)
Where
D ₁ and D ₂ are each independently —CO—O—, —O—CO—, —C (═S) O—,
^{-O-C (= S) -} , - CR 1 R 2 -, - CR 1 R 2 -CR 3 R 4 -, - O-CR 1 R 2 -, - CR 1 R 2 -O -, - CR 1 ^{R 2 -O-CR 3 R 4} -, - CR 1 R 2 -O-CO -, - O-CO-CR 1 R 2 -, - CR 1 R 2 -O-CO-CR 3 R 4 -, - ^{CR 1 R 2 -CO-O-} CR 3 R 4 -, - NR 1 -CR 2 R 3 -, - CR 1 R 2 -NR 3 -, - CO-NR 1 -, or ^-NR 1 -CO- the Represent,
R ¹ , R ² , R ³ , and R ⁴ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms,
G ₁ and G ₂ each independently represent a divalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon group includes —O—, —S—, May be substituted by -NH-, -NH-,
L ₁ and L ₂ each independently represent a monovalent organic group, and at least one selected from the group consisting of L ₁ and L ₂ represents a monovalent group having a polymerizable group,
Ar represents a divalent aromatic ring group represented by the following general formula (II-1), (II-2), (II-3), or (II-4):

In formulas (II-1) to (II-4), Q ₁ represents —S—, —O—, or NR ¹¹ —, and R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ,
Y ₁ represents an aromatic hydrocarbon group having 6 to 12 carbon atoms or an aromatic heterocyclic group having 3 to 12 carbon atoms,
Z ₁ , Z ₂ , and Z ₃ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a monovalent carbon number of 6 20 aromatic hydrocarbon group, a halogen atom, a cyano group, a nitro ^group, a ^-NR 12 ^{R 13} or ^{SR 12,} _{Z 1} and _{Z 2} are bonded to form an aromatic ring or aromatic heterocyclic ring; R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,
A ₁ and A ₂ each independently represents a group selected from the group consisting of —O—, —NR ²¹ — (R ²¹ represents a hydrogen atom or a substituent), —S—, and —CO—; Represents a hydrogen atom or a non-metal atom of Groups 14 to 16 to which a substituent may be bonded, and Ax has at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring Represents an organic group having 2 to 30 carbon atoms, and Ay is a hydrogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, or a group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring. Represents an organic group having 2 to 30 carbon atoms having at least one aromatic ring selected from: Ax and Ay may have a substituent, and Ax and Ay are bonded to form a ring. May be formed,
Q ₂ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.

In the general formula (12), the divalent alicyclic hydrocarbon group represented by G ¹ and G ² is preferably a 5-membered ring or a 6-membered ring. The alicyclic hydrocarbon group may be saturated or unsaturated, but is preferably a saturated alicyclic hydrocarbon group. As the divalent alicyclic hydrocarbon group represented by G ₁ and G ₂ , for example, the description in paragraph 0078 of JP2012-21068A can be referred to, and the contents thereof are incorporated in the present specification.

In General Formula (12), L ₁ and L ₂ are each independently a monovalent organic group, and L ₁ or L ₂ is a monovalent group having a polymerizable group.
Specific examples of the polymerizable group include an ethylenic group such as vinyl group, vinyloxy group, styryl group, p- (2-phenylethenyl) phenyl group, acryloyl group, methacryloyl group, acryloyloxy group, and methacryloyloxy group. Examples include a polymerizable group having a saturated group, carboxy group, acetyl group, hydroxy group, carbamoyl group, alkylamino group having 1 to 4 carbon atoms, amino group, oxiranyl group, oxetanyl group, formyl group, isocyanato group or isothiocyanato group. Is done.

The organic group L ₁ is preferably a group represented by the formula (A1), and L ₂ is preferably a group represented by the formula (A2).
P ¹ -F ^1- (B ¹ -A ¹ ) _k -E ^1- (A1)
P ² -F ^2- (B ² -A ² ) _l -E ^2- (A2)

Wherein (A1) and formula ^{(A2), B 1, B} 2, E 1 and E ^2, each ^{independently, -CR 11 R 12 -, -} CH 2 -CH 2 -, - O -, - S- , —CO—O—, —O—CO—O—, —CS—O—, —O—CS—O—, —CO—NR ¹¹ —, —O—CH ₂ —, —S—CH ₂ — or Represents a single bond. R ¹¹ and R ¹² represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
In formula (A1) and formula (A2), A ¹ and A ² are each independently a divalent alicyclic hydrocarbon group having 5 to 8 carbon atoms or a divalent aromatic carbon group having 6 to 18 carbon atoms. —CH ₂ — representing a hydrogen group and contained in the alicyclic hydrocarbon group may be replaced by —O—, —S— or —NH—, and is contained in the alicyclic hydrocarbon group— CH (-)-may be replaced by -N (-)-. As A ¹ and A ² , the divalent aromatic hydrocarbon group may be monocyclic or polycyclic. For example, the description of paragraph 0083 of JP2012-21068A can be referred to, and the contents thereof are incorporated in the present specification.
k and l each independently represents an integer of 0 to 3. When k is an integer of 2 or more, the plurality of B ¹ and A ¹ may be the same as or different from each other. If l is an integer of 2 or more, a plurality of B ² and A ² may be the same or different from each other.
F ¹ and F ² represents a divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms.
P ¹ and P ² are a hydrogen atom or a polymerizable group, and at least one is a polymerizable group.
In the general formula (12), D ₁ and D ₂ , G ₁ and G _2, and L ₁ and L ₂ are preferably the same.

In General Formula (II-2), when Y ₁ is an aromatic hydrocarbon group having 6 to 12 carbon atoms, it may be monocyclic or polycyclic. When Y ₁ is an aromatic heterocyclic group having 3 to 12 carbon atoms, it may be monocyclic or polycyclic.
In the general formula (II-2), when A ₁ and A ₂ represent —NR ²¹ —, the substituent of R ²¹ can be referred to, for example, the description of paragraphs 0035 to 0045 of JP-A-2008-107767. The contents of which are incorporated herein by reference.
In the general formula (II-2), when X is a nonmetal atom of Group 14 to 16 to which a substituent may be bonded, = O, = S, = NR ', = C (R') R ′ is preferred. R ′ represents a substituent. As the substituent, for example, the description in paragraphs 0035 to 0045 of JP-A-2008-107767 can be referred to, and a nitrogen atom is preferable.

For the definitions and preferred ranges of the substituents of the compound represented by the general formula (12), D ¹ , D ² , G ¹ , G ² , L and the like relating to the compound (A) described in JP2012-21068A are disclosed. ¹ , L ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ X ¹ , Y ¹ , Q ¹ , Q ² are respectively described as D ₁ , D ₂ , G ₁ , G ₂ , L ₁ , L ₂ , R ¹ , R ² , R ³ , R ⁴ , X ¹ , and Y ¹ , Z ₁ , Z ₂ can be referred to, and A for the compound represented by the general formula (I) described in JP-A-2008-107767 ₁ , A ₂ , and X can be referred to for A ₁ , A ₂ , and X, respectively, and Ax, Ay, Q ¹ for the compound represented by the general formula (I) described in WO2013 / 018526 The description is Ax, Ay, Q respectively Reference can be made to ₂ . Regarding Z ₃ , the description relating to Q ¹ relating to the compound (A) described in JP2012-21068A can be referred to.
Although a preferable example is shown below as a compound represented by General formula (12), it is not specifically limited to these.

As the rod-like liquid crystal compound, a compound other than the rod-like liquid crystal compound represented by the general formula (11) or the general formula (12) may be used. For example, at least one compound represented by the following general formula (3) can be used.
General formula (3):
^{Q 3 -SP 3 -X 3 -M 3} -X 4 -R 1
In the formula, Q ³ represents a polymerizable group, preferably a radical polymerizable group or a ring-opening polymerizable group, and more preferably a radical polymerizable group. In particular, a polymerizable group having an ethylenically unsaturated group is preferable. For example, an acryloyl group, a methacryloyl group, an acryloyloxy group, and a methacryloyloxy group are preferable.
SP ³ is a linear or branched alkylene group, or a combination of this and —O— and / or —C (═O) —, and is an integer group having 2 to 8 carbon atoms in total.
X ³ and X ⁴ are each independently a single bond or an oxygen atom.
M ³ is a group consisting of an aromatic ring and —O— and / or —C (═O) —, and a group consisting of a combination of an aromatic ring, —O— and —C (═O) — is preferable. The aromatic ring is preferably an arylene group having 6 to 12 carbon atoms. The aromatic ring may have a substituent, and the substituent is preferably an alkoxy group having 1 to 4 carbon atoms.
R ¹ is a hydrocarbon group. The hydrocarbon group preferably has a cyclic alkylene group, and is preferably a group composed of a combination of a cyclic alkylene group having 3 to 8 carbon atoms and an alkyl group having 1 to 5 carbon atoms.

  The rod-like liquid crystal compound is preferably 50 to 98 mass%, more preferably 70 to 97 mass%, based on the total solid content of the composition for forming the optically anisotropic layer. When two or more kinds of rod-like liquid crystal compounds are used, the total amount is preferably within the above range.

<<< Polymerization initiator >>>
The liquid crystal compound undergoes a polymerization reaction of a polymerizable group introduced into the liquid crystal compound in order to maintain and fix the alignment state. Therefore, the composition for forming the optically anisotropic layer preferably contains a polymerization initiator. As the polymerization initiator, the same ones as described in the alignment layer can be used.
As for the addition amount of a polymerization initiator, 1-10 mass% is preferable with respect to the mass of a rod-shaped liquid crystal compound. When two or more kinds of polymerization initiators are used, the total amount is preferably within the above range.

  Examples of other additives for forming an optically anisotropic layer include surfactants for controlling surface properties and surface shapes, and additives (alignment aids) for controlling the tilt angle of liquid crystal compounds. , An additive (plasticizer) for lowering the orientation temperature, the above-described fluorine-containing compound, the above-described polymerizable monomer, other chemicals for imparting functionality, and the like can be used as appropriate.

<<< Optical Properties of Optically Anisotropic Layer >>>
The in-plane retardation Re of the optically anisotropic layer on the surface of the alignment layer at a wavelength of 550 nm is preferably 100 to 180 nm, and more preferably 120 to 160 nm.
The retardation Rth in the thickness direction at a wavelength of 550 nm of the optically anisotropic layer is preferably 50 to 90 nm, and more preferably 60 to 80 nm.
The in-plane retardation Re450 at a wavelength of 450 nm and the in-plane retardation Re550 at a wavelength of 550 nm of the optically anisotropic layer preferably satisfy the following formula 1, and more preferably satisfy the following formula 1-1.
Formula 1: 0.70 ≦ Re450 / Re550 ≦ 0.95
Formula 1-1: 0.80 ≦ Re450 / Re550 ≦ 0.95

  The optically anisotropic layer on the surface of the alignment layer is preferably a positive A plate that satisfies nx> ny = nz. nx represents the refractive index in the slow axis direction in the plane of the optically anisotropic layer, ny represents the refractive index in the direction perpendicular to nx in the plane of the optically anisotropic layer, and nz represents the refractive index in the direction perpendicular to nx and ny. Represents a rate.

<< Another optically anisotropic layer >>
The polarizing plate of the present invention is another optically anisotropic layer formed from a rod-like liquid crystal compound on the optically anisotropic layer on the surface of the alignment layer (hereinafter also referred to as a second optically anisotropic layer). May further be included. In the second optically anisotropic layer, the rod-like liquid crystal compound is preferably vertically aligned with respect to the polarizer surface.

  For the liquid crystal compound that can be used for the second optically anisotropic layer, for example, the description in paragraphs 0045 to 0066 of JP-A-2009-217256 can be referred to, and the contents thereof are incorporated in the present specification.

  The liquid crystal compound forming the second optically anisotropic layer preferably contains at least one of a compound represented by the following general formula (31A) and a compound represented by the following general formula (31B).

General formula (31A)

General formula (31B)

R _{1 to} R ₄ are each independently — (CH ₂ ) _n —OOC—CH═CH ₂ , and n represents an integer of 2 to 5. X and Y each independently represent a hydrogen atom or a methyl group.
From the viewpoint of suppressing crystal precipitation, in the general formula (31A) or (31B), X and Y preferably represent a methyl group.

  The content of the liquid crystal compound in the composition for forming the second optically anisotropic layer is not particularly limited, but is preferably 70 to 95% by mass, and 80 to 95% by mass with respect to the total solid content. It is more preferable that it is 0.05-3 mass%. When two or more kinds of liquid crystal compounds are used, the total amount is preferably within the above range.

  In addition to the liquid crystal compound, a vertical alignment agent, a fluorine-containing compound, a polymerizable monomer, a polymerization initiator, and the like can be added to the composition for forming the second optically anisotropic layer. The amount used is as described above in connection with the alignment layer and the optical anisotropy on the surface of the alignment layer. Further, a sensitizer (for example, Kayacure (registered trademark) DETX (manufactured by Nippon Kayaku Co., Ltd.)) can also be added.

The second optically anisotropic layer is preferably a positive C plate that satisfies nz> nx = ny.
That is, as the polarizing plate of the present invention, a polarizing plate in which the optically anisotropic layer on the surface of the alignment layer is a positive A plate and a positive C plate is provided thereon as the second optically anisotropic layer. Is particularly preferred. With such a configuration, for example, in a liquid crystal display device, high panel contrast can be achieved and light leakage in an oblique direction can be suppressed.

The second optically anisotropic layer preferably satisfies −5 ≦ Re (550) ≦ 5 (| Re (550) | ≦ 5), and −3 ≦ Re (550) ≦ 3 (| Re (550). It is more preferable to satisfy | ≦ 3).
The second optically anisotropic layer preferably satisfies −300 ≦ Rth (550) ≦ 0, more preferably satisfies −200 ≦ Rth (550) ≦ −20, and −150 ≦ Rth (550) ≦. It is more preferable to satisfy −50.

<< Polarizing plate protective film >>
The polarizing plate of this invention may have a polarizing plate protective film on the surface on the opposite side to the orientation layer on a polarizer. As a polarizing plate protective film, it can be used with what has a cellulose-ester film and a hard-coat layer, for example.
As the cellulose ester, cellulose acylate is preferable. Examples of the cellulose as the acylate material include cotton linter and wood pulp (hardwood pulp, conifer pulp). Cellulose acylate obtained from any of the raw material celluloses can be used, and in some cases, they may be mixed and used. Detailed descriptions of these raw material celluloses can be found in, for example, Marusawa and Uda, “Plastic Materials Course (17) Fibrous Resin”, published by Nikkan Kogyo Shimbun (published in 1970), and the Japan Society of Invention and Innovation Technical Bulletin No. 2001. The cellulose described in No.-1745 (pages 7 to 8) can be used. Regarding the cellulose acylate, the description in paragraphs 0027 to 0065 of JP-A No. 2014-121790 can be referred to, and the contents thereof are incorporated in the present specification.

  The hard coat layer is a layer formed by curing a curable compound. A curable compound is a compound that is cured by light or heat. Specifically, a material having a curable functional group having a vinyl group, an allyl group, a (meth) acryloyl group, a glycidyl group, an epoxy group, or the like is an example. Can be mentioned. The curable compound may be a low molecular compound, an oligomer, or a polymer (resin). More specifically, examples of the curable compound include esters of polyhydric alcohol and (meth) acrylic acid, vinylbenzene and derivatives thereof, vinyl sulfone, (meth) acrylamide, polyester resin, polyether resin, acrylic resin, epoxy. Examples thereof include oligomers or prepolymers such as polyfunctional compounds such as resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and polyhydric alcohols.

<< Specific Examples of Polarizing Plate >>
A particularly preferred embodiment of the polarizing plate of the present invention will be described with reference to FIG. The polarizing plate shown in FIG. 1 includes a polarizing plate protective film 1, a polarizer 2 on the surface of the polarizing plate protective film 1, an alignment layer 3 on the surface of the polarizer 2, and an optically anisotropic layer on the surface of the alignment layer 3. 4 and the second optical anisotropic layer 5 on the surface of the optical anisotropic layer 4. The optically anisotropic layer 4 is a positive A plate that satisfies nx> ny = nz, and the second optically anisotropic layer 5 is a positive C plate that satisfies nz> nx = ny. In the polarizing plate shown in FIG. 1, the alignment layer 3 is formed of a discotic liquid crystal compound, and the discotic liquid crystal compound is vertically aligned with respect to the polarizer plane. The slow axis of the alignment layer 3 is orthogonal to the absorption axis direction of the polarizer 2. The optically anisotropic layer 4 is formed from a rod-like liquid crystal compound, and the slow axis of the optically anisotropic layer 4 is orthogonal to the absorption axis direction of the polarizer 2.

<Production method of polarizing plate>
<< Step of rubbing the surface of the polarizer >>
For the rubbing treatment of the polarizer, a treatment method widely adopted as a liquid crystal alignment treatment step of the liquid crystal display device can be applied. That is, a method of obtaining orientation by rubbing the polarizer surface in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. In general, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are flocked on average.

<< Step of forming alignment layer >>
The step of forming the alignment layer is to apply the composition for the alignment layer containing the discotic liquid crystal compound to the surface of the rubbed polarizer and heat-treat as necessary to align the discotic liquid crystal compound. It is preferable to contain.
The composition for an alignment layer containing a discotic liquid crystal compound can be prepared by mixing the discotic liquid crystal compound and, if necessary, the above-described components together with a solvent to form a coating solution. The solvent that can be used is not particularly limited, but is preferably selected from at least one member selected from the group consisting of ketones, esters, ethers, alcohols, alkanes, toluene, chloroform, and methylene chloride. More preferably, it is selected from at least one member selected from the group consisting of alkanes, and particularly preferably selected from at least one member selected from the group consisting of ketones, esters, ethers and alcohols. The amount of the solvent used is generally 50 to 98% by mass as the concentration in the composition, but is not particularly limited.

The alignment layer composition can be applied by a known method (for example, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, or a die coating method).
As for the conditions for the heat treatment, an optimum temperature is appropriately selected according to the type of the discotic liquid crystal compound to be used, but it is usually 20 to 200 ° C. (preferably 60 to 160 ° C.) for 10 to 600 seconds. (Preferably, 30 to 300 seconds) It is preferable to perform heat treatment.
By carrying out ultraviolet irradiation, the reaction proceeds between the polymerizable groups, and the alignment state is fixed. UV irradiation dose is preferably ^{100~300mJ / cm 2, 150~250mJ / cm} 2 is more preferable.

<< Step of forming optically anisotropic layer >>
The step of forming the optically anisotropic layer on the surface of the alignment layer is performed by applying a composition for an optically anisotropic layer containing a rod-shaped liquid crystal compound to the surface of the alignment layer and subjecting it to a heat treatment as necessary. It preferably includes fixing the orientation state of the compound.
The composition for an optically anisotropic layer can be prepared by mixing a rod-like liquid crystal compound and, if necessary, the above-described components together with a solvent to form a coating solution. The kind and amount of the solvent that can be used are the same as those described for the composition for the alignment layer.
The coating method is the same as the step of forming the alignment layer. The conditions for fixing the alignment state are the same as in the step of forming the alignment layer.
The heat treatment is preferably performed at a temperature of 40 to 90 ° C. (preferably 40 to 80 ° C.) for 10 to 600 seconds (preferably 30 to 300 seconds).
UV irradiation dose is preferably ^{100~300mJ / cm 2, 150~250mJ / cm} 2 is more preferable.

<< Step of Forming Second Optically Anisotropic Layer >>
In the step of forming the second optically anisotropic layer, a second optically anisotropic layer composition containing a liquid crystal compound is applied on the first optically anisotropic layer, and heated as necessary. It is preferable to include a treatment to fix the alignment state of the liquid crystal compound.
The second optical anisotropic layer may be formed on the surface of the first optical anisotropic layer. Alternatively, an intermediate layer may be formed on the surface of the first optical anisotropic layer, and then the second optical anisotropic layer may be formed on the surface of the intermediate layer. Preferably, the second optical anisotropic layer is formed on the surface of the first optical anisotropic layer. When the intermediate layer is provided on the surface of the first optically anisotropic layer, the type of the intermediate layer is not particularly limited, but a resin having a thickness of 3.0 μm or less and an SP value of 21.5 to 24.7 is used. It is preferable to include. By using a resin having an SP value of 21.5 to 24.7, the second optically anisotropic layer has excellent adhesion to the second optically anisotropic layer, and a homogeneous orientation of the second optically anisotropic layer can be realized. A thin and smooth layer can be formed. The intermediate layer may have a surface roughness (Ra) of, for example, 5 to 200 nm. The SP value means a solubility parameter; an SP value calculated based on the Hoy method. The SP value is preferably 21.5 to 24.7, and more preferably 22.5 to 24.0. The film thickness of the intermediate layer is preferably 0.05 to 2.5 μm, more preferably 0.08 to 2.3 μm, and still more preferably 0.2 to 1.5 μm. Examples of the resin having an SP value of 21.5 to 24.7 include (meth) acrylic resin, bromine-based resin, modified styrene-based resin such as styrene-acrylonitrile-N-phenylmaleimide terpolymer (SAM) and parahydroxystyrene. And (meth) acrylic resin is preferable.

  The second composition for an optically anisotropic layer can be prepared by mixing the liquid crystal compound and, if necessary, the above-described components together with a solvent to form a coating solution. The kind and amount of the solvent that can be used are the same as those described for the composition for the alignment layer.

The coating method of the second composition for optically anisotropic layer is the same as the step of forming the alignment layer.
The heat treatment is preferably performed at a temperature of 40 to 90 ° C. (preferably 40 to 70 ° C.) for 10 to 600 seconds (preferably 30 to 300 seconds).
UV irradiation dose is preferably ^{100~300mJ / cm 2, 150~250mJ / cm} 2 is more preferable.

<Liquid crystal display device>
The present invention also relates to a liquid crystal display device including at least one polarizing plate of the present invention.
The liquid crystal display device includes a liquid crystal cell in which liquid crystal is supported between two electrode substrates, two polarizing plates disposed on both sides thereof, and at least one between the liquid crystal cell and the polarizing plate as necessary. It has a configuration in which a single optical compensation film is arranged.
The liquid crystal layer of the liquid crystal cell is usually formed by sealing liquid crystal in a space formed by sandwiching a spacer between two substrates. The transparent electrode layer is formed on the substrate as a transparent film containing a conductive substance. The liquid crystal cell may further be provided with a gas barrier layer, a hard coat layer, or an undercoat layer. These layers are usually provided on the substrate.

  In a liquid crystal display device, a substrate including a liquid crystal cell is usually disposed between two polarizing plates (a viewing side polarizing plate and a backlight side polarizing plate). The polarizing plate of the present invention can be used as a viewing side polarizing plate and / or a backlight side polarizing plate in a liquid crystal display device.

  The polarizing plate of the present invention can be used for liquid crystal cells in various display modes. TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-Ferroly Liquid Liquid Crystal), OCB (Optically QuantNW). Various display modes such as ECB (Electrically Controlled Birefringence) and HAN (Hybrid Aligned Nematic) have been proposed. In addition, a display mode in which the above display mode is oriented and divided has been proposed. The optical film of the present invention can be used in a liquid crystal display device of any display mode, and the IPS mode is particularly preferable. Further, it is effective in any of a transmissive type, a reflective type, and a transflective liquid crystal display device.

  The features of the present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. The scope of the present invention should not be construed as being limited by the specific examples shown below. Re and Rth in the examples were measured by KOBRA 21ADH (manufactured by Oji Scientific Instruments).

[Example 1]
<Preparation of polarizing plate protective film>
(Preparation of cellulose ester solution for air layer)
The following components were put into a mixing tank and stirred while heating to dissolve each component to prepare an air layer cellulose ester solution.

Composition of cellulose ester solution for air layer Cellulose ester (acetyl substitution degree 2.86) 100 parts by mass of sugar ester compound of formula (R-I) 3 parts by mass of sugar ester compound of formula (R-II) 1 part by mass UV absorption below Agent 2.4 parts by mass of silica particle dispersion 0.026 parts by mass (AEROSIL (registered trademark) R972, average particle size: 16 nm, manufactured by Nippon Aerosil Co., Ltd.)
Methylene chloride 339 parts by mass Methanol 74 parts by mass Butanol 3 parts by mass

(Preparation of cellulose ester solution for drum layer)
The following components were put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose ester solution for a drum layer.

Composition of cellulose ester solution for drum layer Cellulose ester (acetyl substitution degree 2.86) 100 parts by mass of sugar ester compound of formula (R-I) 3 parts by mass of sugar ester compound of formula (R-II) 1 part by mass Agent 2.4 parts by mass Silica particle dispersion 0.091 parts by mass (AEROSIL R972, average particle size: 16 nm, manufactured by Nippon Aerosil Co., Ltd.)
Methylene chloride 339 parts by mass Methanol 74 parts by mass Butanol 3 parts by mass

(Preparation of cellulose ester solution for core layer)
The following components were put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose ester solution for the core layer.

Composition of cellulose ester solution for core layer Cellulose ester (acetyl substitution degree 2.86) Sugar ester compound of 100 parts by mass (R-II) 8.3 parts of sugar ester compound of formula (R-II) 2.8 masses Parts UV absorber 2.4 parts methylene chloride 266 parts methanol 58 parts butanol 2.6 parts

(Co-casting film formation)
As a casting die, an apparatus equipped with a feed block adjusted for co-casting so that a film having a three-layer structure can be formed was used. The cellulose ester solution for the air layer, the cellulose ester solution for the core layer, and the cellulose ester solution for the drum layer were co-cast on a drum cooled to -7 ° C from the casting port. At this time, the flow rate of each dope was adjusted so that the thickness ratio was air layer / core layer / drum layer = 7/90/3.
It casted on the mirror surface stainless steel support body which is a drum of diameter 3m. A dry air of 34 ° C. was applied on the drum at 270 m ³ / min.
The cellulose ester film cast and rotated 50 cm before the end point of the casting part was peeled off from the drum, and then both ends were clipped with a pin tenter. During peeling, 5% stretching was performed in the transport direction (longitudinal direction).

The cellulose ester web held by the pin tenter was conveyed to the drying zone. In the first drying, a drying air of 45 ° C. was blown and then dried at 110 ° C. for 5 minutes. At this time, the cellulose ester web was conveyed while stretching in the width direction at a magnification of 10%.
After the web was detached from the pin tenter, the portion held by the pin tenter was continuously cut out, and unevenness with a width of 15 mm and a height of 10 μm was made at both ends in the width direction of the web. The width of the web at this time was 1610 mm. It was dried at 140 ° C. for 10 minutes while applying a tensile stress of 210 N in the transport direction. Furthermore, the width direction edge part was continuously cut out so that a web might become a desired width | variety, and the 41-micrometer-thick cellulose ester film was produced.

(Preparation of hard coat layer)
The following curable resin composition was prepared as a coating liquid for forming a hard coat layer.
(Curable resin composition)
KAYARAD (registered trademark) DPHA [manufactured by Nippon Kayaku Co., Ltd.] 48.5 parts by mass KAYARAD PET30 [manufactured by Nippon Kayaku Co., Ltd.] 48.5 parts by mass Irgacure (registered trademark) 127: polymerization initiator [manufactured by BASF] 3.0 parts by mass Toluene 97.0 parts by mass Cyclohexanone 3.0 parts by mass

On the cellulose ester film produced above, the curable resin composition was applied by a die coating method using a slot die described in Example 1 of JP-A-2006-122889 under the condition of a conveyance speed of 30 m / min. And dried at 60 ° C. for 60 seconds. Thereafter, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) with a nitrogen purge (oxygen concentration of about 0.1% by volume), an illuminance of 400 mW / cm ² and an irradiation amount of 390 mJ / cm ² The coating layer was cured by irradiating with ultraviolet rays and wound up. The coating amount was adjusted so that the thickness of the cured layer was 4 μm. In this way, a polarizing plate protective film with a hard coat layer having a total film thickness of 45 μm (hereinafter, also simply referred to as “polarizing plate protective film”) was produced.

<Preparation of polarizer with protective film for polarizing plate>
A polarizing plate protective film was prepared and immersed in a 1.5 mol / L NaOH aqueous solution (saponification solution) maintained at 55 ° C. for 2 minutes, and then the film was washed with water. Thereafter, the film was immersed in a 0.05 mol / L sulfuric acid aqueous solution at 25 ° C. for 30 seconds, and then a washing bath was passed under running water for 30 seconds to make the film neutral. Then, draining with an air knife was repeated three times, and after dropping water, the film was retained in a drying zone at 70 ° C. for 15 seconds and dried to prepare a saponified polarizing plate protective film.
According to Example 1 of JP 2001-141926 A, a 15 μm thick polarizer containing a dichroic dye and a polyvinyl alcohol resin, which gives a peripheral speed difference between two pairs of nip rolls and is stretched in the longitudinal direction. Prepared. Then, the polarizing plate protective film which carried out the saponification process was bonded together to the single side | surface of the said polarizer using the polyvinyl alcohol adhesive, and it dried at 70 degreeC for 10 minutes or more, and produced the polarizer with a polarizing plate protective film. Here, it arrange | positioned so that the transmission axis of a polarizer and the conveyance direction of a film might orthogonally cross. At the time of bonding, the film side in the polarizing plate protective film was bonded to the polarizer side.

<Preparation of alignment layer A>
The rubbing process was continuously performed on the polarizer surface of the polarizer with a polarizing plate protective film prepared above in the longitudinal direction of the polarizer, that is, the absorption axis direction of the polarizer. The following coating solution for alignment layer A was applied onto the rubbing surface using a # 2.0 bar coater. Next, after aging by heating at a film surface temperature of 60 ° C. for 60 seconds, an ultraviolet ray irradiation dose of 200 mJ / cm ² is used using an air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) of 20 mW / cm ² at 70 ° C. in the air. Then, the alignment layer A was formed by fixing the alignment state. The slow axis of the formed alignment layer A was orthogonal to the absorption axis direction of the polarizer, and the discotic liquid crystal compound was aligned perpendicular to the polarizer plane. The thickness of the alignment layer A was 133 nm.
Re550 of the alignment layer A was 12 nm, and Rth550 was −6 nm.

────────────────────────────────────
Composition of alignment layer A coating solution ────────────────────────────────────
Discotic liquid crystal E-1 80 parts by weight Discotic liquid crystal 2 20 parts by weight Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 10 parts by weight Photopolymerization initiator 6.0 parts by weight ( (Irgacure 819, manufactured by BASF)
Vertical alignment agent (S01) 8.26 parts by mass Vertical alignment agent (S02) 0.73 parts by mass Fluorine-containing compound A 1.0 part by mass Fluorine-containing compound B 0.4 parts by mass Methyl ethyl ketone 2401 parts by mass ────── ──────────────────────────────

<Preparation of optically anisotropic layer>
The following coating liquid S for optically anisotropic layers was prepared. When this coating solution S for optically anisotropic layers was applied to the surface of a slide glass and observed with a polarizing microscope while heating, the phase transition temperature of smectic A phase-nematic phase was 74 ° C., and isotropic phase transition temperature. Was 132 ° C.
───────────────────────────────────
Composition of coating solution S for optically anisotropic layer ───────────────────────────────────
Bar-shaped liquid crystal compound II-2-3 57.5 parts by mass Bar-shaped liquid crystal compound II-2-4 30.0 parts by mass Bar-shaped compound RL-2 12.5 parts by mass Photopolymerization initiator 1 3.0 parts by mass (Irgacure 819, (Made by BASF)
Photopolymerization initiator 2 6.0 parts by mass The above fluorine-containing compound A 0.85 parts by mass Cyclopentanone 269 parts by mass ─────────────────────── ──────────

On the surface of the alignment layer A, the coating solution S for optically anisotropic layer was applied using a # 4.4 bar coater. After aging by heating at a film surface temperature of 80 ° C. for 60 seconds, cooling to 60 ° C. to exhibit a smectic A phase, 200 mJ using an air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) of 70 mW / cm ² under air. The optically anisotropic layer A was produced by irradiating / cm ² of ultraviolet rays and fixing the alignment state with the smectic A phase. In the formed optically anisotropic layer A, rod-like liquid crystal compounds II-2-3 and II-2-4 were aligned in a direction orthogonal to the absorption axis direction of the polarizer. That is, the slow axis of the optically anisotropic layer was orthogonal to the absorption axis direction of the polarizer. At this time, the thickness of the optically anisotropic layer was 2 μm. Using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments), the light incident angle dependence of Re was measured. At a wavelength of 550 nm, Re was 143 nm, Rth was 72 nm, and Re (450) / Re (550) was 0.88.

<Preparation of second optically anisotropic layer>
The second optical anisotropic layer coating liquid C described below is applied to the surface of the optically anisotropic layer A produced above, and after aging at 40 ° C. for 60 seconds, an air-cooled metal halide of 70 mW / cm ² under air. The second optical anisotropy was produced by fixing the alignment state by irradiating 200 mJ / cm ² ultraviolet rays using a lamp (manufactured by Eye Graphics Co., Ltd.). At this time, the rod-like liquid crystal compound of the second optical anisotropic layer was vertically aligned. The Rth of the second optical anisotropic layer at a wavelength of 550 nm was −97 nm.

───────────────────────────────────
Composition of coating liquid C for the second optically anisotropic layer ───────────────────────────────────
Liquid crystal compound B01 80 parts by mass Liquid crystal compound B02 20 parts by mass Vertical alignment agent S01 1 part by mass Vertical alignment agent S02 0.5 part by mass Ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 8 1 part by weight B03 0.4 part by weight methyl ethyl ketone 220 parts by weight cyclohexanone 39 parts by weight 39 parts by weight Irgacure 907 (by BASF) 3 parts by weight Kayacure DETX (by Nippon Kayaku Co., Ltd.) ─────────────────────────

[Example 2]
An alignment layer was prepared in the same manner as in Example 1 except that 6193 parts by mass of methyl ethyl ketone in the coating liquid for alignment layer A and 247 parts by mass of cyclopentanone in the coating liquid S for optically anisotropic layer were used. The thickness of the alignment layer was 53 nm. In the same manner as in Example 1, a polarizing plate on which the second optically anisotropic layer was applied and laminated was produced.

[Example 3]
An alignment layer was prepared in the same manner as in Example 1, except that 12513 parts by mass of methyl ethyl ketone in the coating liquid for alignment layer A and 240 parts by mass of cyclopentanone in the coating liquid S for optically anisotropic layer were used. The thickness of the alignment layer was 27 nm. In the same manner as in Example 1, a polarizing plate on which the second optically anisotropic layer was applied and laminated was produced.

[Example 4]
An alignment layer was prepared in the same manner as in Example 1 except that 1453 parts by mass of methyl ethyl ketone in the coating liquid for alignment layer A and 293 parts by mass of cyclopentanone in the coating liquid S for optically anisotropic layer were used. The thickness of the alignment layer was 212 nm. In the same manner as in Example 1, a polarizing plate on which the second optically anisotropic layer was applied and laminated was produced.

[Example 5]
On the surface of the alignment layer A, a coating solution containing 251 parts by mass of the cyclopentanone of the coating solution S for optically anisotropic layer was applied using a # 4.4 bar coater. Using a 70 mW / cm ² air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) under the condition of heating and aging at a film surface temperature of 80 ° C. for 60 seconds and exhibiting a nematic phase at 80 ° C., 200 mJ / An optically anisotropic layer N1 was produced by irradiating cm ² ultraviolet rays and fixing the alignment state in a nematic phase. A polarizing plate on which the second optically anisotropic layer was applied and laminated was produced in the same manner as in Example 1 except that the optically anisotropic layer N1 was produced.

[Comparative Example 1]
The alignment layer was the same as that of Example 1 except that the alignment film B was prepared using polyimide (PI-8) having a carbazole skeleton described in Example 1 of JP-A-2002-268068. Specifically, polyimide (PI-8) was dissolved in a mixed solvent of N-methylpyrrolidone / methyl ethyl ketone (mass ratio = 1/4) to prepare a 4 mass% solution. This solution was applied to a thickness of 106 nm on a glass support using a # 2.0 bar coater. The coating layer was heated at 120 ° C. for 5 minutes and dried. In the same manner as in Example 1, a polarizing plate on which the second optically anisotropic layer was applied and laminated was produced.

[Example 6]
An optically anisotropic layer N2 was prepared in the same procedure as in Example 1, except that the coating liquid S for optically anisotropic layer was changed to the coating liquid N for optically anisotropic layer. The coating liquid N for optically anisotropic layer did not show a smectic phase, was a nematic phase, and Re450 / Re550 was 1.08. In the same manner as in Example 1, a polarizing plate on which the second optically anisotropic layer was applied and laminated was produced.

───────────────────────────────────
Composition of coating liquid N for optically anisotropic layer ───────────────────────────────────
Rod-shaped compound RL-4 80 parts by weight Rod-shaped compound RL-5 20 parts by weight Photopolymerization initiator 3.0 parts by weight (Irgacure 907, manufactured by BASF)
Fluorine-containing compound A 0.8 parts by mass Methyl ethyl ketone 311 parts by mass ───────────────────────────────────

[Production and Evaluation of Liquid Crystal Display]
<Production of liquid crystal display device>
The polarizing plate on the viewing side was peeled off from a liquid crystal cell of iPad (registered trademark, manufactured by Apple) and used as an IPS mode liquid crystal cell.
Instead of the peeled polarizing plate, the polarizing plates on which the second optically anisotropic layers prepared in Examples 1 to 6 and Comparative Example 1 were laminated were bonded to a liquid crystal cell, and liquid crystal display devices 1 to 7 were produced. did. At this time, the substrates were bonded so that the absorption axis of the polarizing plate and the optical axis of the liquid crystal layer in the liquid crystal cell were perpendicular to each other when observed from the direction perpendicular to the liquid crystal cell substrate surface.
Moreover, instead of the peeled polarizing plate, the polarizer with a polarizing plate protective film produced in Example 1 was used as the polarizing plate of Comparative Example 2, and was bonded to the liquid crystal cell so that the polarizer was on the liquid crystal cell side. A liquid crystal display device 8 was produced.

<Evaluation of liquid crystal display device>
The display performance was measured using a commercially available liquid crystal viewing angle and chromaticity characteristic measuring device Ezcontrast (manufactured by ELDIM), and a backlight using a commercially available liquid crystal display device iPad (manufactured by Apple). The liquid crystal cell to which the polarizing plate was bonded was placed and measured such that the optically anisotropic layer was on the side opposite to the backlight side. The results are shown in Table 3 below.

(Panel front contrast)
The luminance (Yw) from the vertical direction with respect to the panel in white display and the luminance (Yb) from the vertical direction with respect to the panel in black display are measured, and the contrast ratio (Yw / Yb) in the vertical direction with respect to the panel is measured. Calculation was made and the panel front contrast was evaluated according to the following criteria.
A: Panel front contrast is 95% or more with respect to Comparative Example 2 B: Panel front contrast is 85% to less than 95% with respect to Comparative Example 2 C: Panel front contrast is 75% to 85% with respect to Comparative Example 2. Less than D: Panel front contrast is less than 75% of Comparative Example 2

(Oblique light leakage)
A value (luminance max) obtained by averaging the maximum values of the black luminance (Cd / m ² ) in the upward direction (azimuth angle 0 to 180 °, in increments of 5 °) and in the downward direction (azimuth angle 180 to 360 °, in increments of 5 °). )showed that. The smaller the numerical value, the less the light leakage of black display, and the evaluation was made in the following four grades A to D.
A: 1 or less B: 1 or more, 2 or less C: 2 or more, 5 or less D: 10 or more

(Summary of Examples)
The alignment layer is formed of a discotic liquid crystal compound, and the discotic liquid crystal compound is vertically aligned with respect to the polarizer surface, and the slow axis of the alignment layer is orthogonal to the absorption axis direction of the polarizer, so The liquid crystal display devices 1 to 6 manufactured using the polarizing plates of Examples 1 to 6 in which the slow axis of the isotropic layer is orthogonal to the absorption axis direction of the polarizer have panel front contrast and oblique direction light. Both leaks were good. In particular, the liquid crystal display devices 1 to 5 produced using the polarizing plates of Examples 1 to 5 had better panel front contrast and oblique light leakage. On the other hand, the liquid crystal display device using the polarizing plate of Comparative Example 1 in which the alignment layer was formed of polyimide had poor panel front contrast.

DESCRIPTION OF SYMBOLS 1 Polarizing plate protective film 2 Polarizer 3 Orientation layer 4 Optical anisotropic layer 5 2nd optical anisotropic layer

Claims (15)

A polarizer, an alignment layer on the surface of the polarizer, and an optically anisotropic layer on the surface of the alignment layer, wherein the alignment layer is formed of a discotic liquid crystal compound, and the discotic liquid crystal compound is It is vertically aligned with respect to the polarizer surface, the slow axis of the alignment layer is orthogonal to the absorption axis direction of the polarizer, the optically anisotropic layer is formed of a rod-like liquid crystal compound, A polarizing plate, wherein the slow axis of the optically anisotropic layer is orthogonal to the absorption axis direction of the polarizer. The polarizing plate according to claim 1, wherein the alignment layer has a thickness of 0.5 μm or less. The polarizing plate according to claim 1, wherein the polarizer contains a dichroic dye. The polarizing plate as described in any one of Claim 1 to 3 whose retardation Re of the in-plane direction in wavelength 550nm of the said optically anisotropic layer is 100-180 nm. The polarizing plate as described in any one of Claim 1 to 4 whose retardation Rth of the thickness direction in wavelength 550nm of the said optically anisotropic layer is 50-90 nm. 6. The polarizing plate according to claim 1, wherein the in-plane retardation Re450 at a wavelength of 450 nm and the in-plane retardation Re550 at a wavelength of 550 nm of the optically anisotropic layer satisfy the following formula 1.
Formula 1: 0.70 ≦ Re450 / Re550 ≦ 0.95 The polarizing plate according to any one of claims 1 to 6, wherein the rod-like liquid crystal compound is a nematic liquid crystal compound and / or a smectic liquid crystal compound. The polarizing plate according to any one of claims 1 to 7, wherein the rod-like liquid crystal compound is horizontally aligned with respect to a polarizer surface in the optically anisotropic layer. The optically anisotropic layer further includes a second optically anisotropic layer formed of a rod-like liquid crystal compound, and the rod-like liquid crystal compound is in the second optically anisotropic layer with respect to the polarizer surface. The polarizing plate according to claim 8 , which is vertically aligned. The polarizing plate according to claim 9 , wherein the optically anisotropic layer on the surface of the alignment layer satisfies nx> ny = nz, and the second optically anisotropic layer satisfies nz> nx = ny.
However, nx represents the refractive index in the slow axis direction in the optically anisotropic layer surface, ny represents the refractive index in the direction orthogonal to nx in the optically anisotropic layer surface, and nz is the direction orthogonal to nx and ny. Represents the refractive index. The polarizing plate as described in any one of Claim 1 to 10 which has a polarizing plate protective film on the surface on the opposite side to the orientation layer on a polarizer. A polarizing plate protective film, a polarizer on the surface of the polarizing plate protective film, an alignment layer on the surface of the polarizer, a first optical anisotropic layer on the surface of the alignment layer, and the first optical difference A polarizing plate having a second optically anisotropic layer on the isotropic layer,
The first optical anisotropic layer satisfies nx> ny = nz, the second optical anisotropic layer satisfies nz> nx = ny,
The alignment layer is formed of a discotic liquid crystal compound, and the discotic liquid crystal compound is aligned perpendicularly to a polarizer surface, and a slow axis of the alignment layer is orthogonal to an absorption axis direction of the polarizer. And
The first optically anisotropic layer is made of a rod-like liquid crystal compound, and the slow axis of the first optically anisotropic layer is orthogonal to the absorption axis direction of the polarizer;
However, nx represents the refractive index in the slow axis direction in the optically anisotropic layer surface, ny represents the refractive index in the direction orthogonal to nx in the optically anisotropic layer surface, and nz is the direction orthogonal to nx and ny. Represents the refractive index. Rubbing the surface of the polarizer;
Applying a composition containing a discotic liquid crystal compound on the surface of the rubbed polarizer to form an alignment layer;
The manufacturing method of the polarizing plate of any one of Claim 1 to 12 including the process of apply | coating the composition containing a rod-shaped liquid crystal compound on the surface of the said alignment layer, and forming an optically anisotropic layer. A liquid crystal display device comprising the polarizing plate according to claim 1 . The liquid crystal display device according to claim 14 , which is in an IPS mode.

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