JPWO2019116991A1 - Liquid crystal alignment layer and its manufacturing method, optical film and its manufacturing method, 1/4 wave plate, polarizing plate and organic electroluminescence display panel - Google Patents

Abstract

A liquid crystal alignment layer containing a molecule of the liquid crystal compound formed of a cured product of an alignment layer composition containing a liquid crystal compound capable of exhibiting reverse wavelength dispersive double refraction and having a fixed orientation state, wherein the liquid crystal orientation. At least a part of the molecules of the liquid crystal compound contained in the layer are inclined with respect to the layer plane of the liquid crystal oriented layer, and the liquid crystal oriented layer has a surface having a surface free energy of 40 mJ / m2 or more. Liquid crystal alignment layer.

Description

The present invention relates to a liquid crystal alignment layer and a method for producing the same, an optical film and the method for producing the same, a quarter wave plate, a polarizing plate, and an organic electroluminescence display panel.

As one of the optical films, a film produced by using a liquid crystal compound is known. This film generally comprises a liquid crystal cured layer formed of a cured product in which a liquid crystal composition containing a liquid crystal compound is oriented and cured while maintaining the oriented state. As such an optical film, the one described in Patent Document 1 has been proposed.

Japanese Patent No. 5363022

The liquid crystal cured layer included in the optical film usually contains a liquid crystal compound. The molecules of this liquid crystal compound may be inclined with respect to the layer plane of the liquid crystal cured layer. When an optical film provided with a liquid crystal curing layer containing a liquid crystal compound having tilted molecules is provided in an image display device, the tilt angle of the molecules of the liquid crystal compound is appropriately adjusted in order to obtain good viewing angle characteristics. It is desirable to do.

Specifically, the organic electroluminescence display panel (hereinafter, may be appropriately referred to as “organic EL display panel”) has circularly polarized light as a reflection suppressing film for suppressing reflection of external light on the display surface. A polarizing plate such as a plate and an elliptical polarizing plate may be provided. This polarizing plate usually includes a combination of a linear polarizer and a retardation film. From the viewpoint of suppressing reflection and obtaining excellent viewing angle characteristics when the display surface is viewed from an inclined direction, it is preferable to adjust birefringence in the thickness direction of the retardation film. Therefore, in order to realize a retardation film having appropriate birefringence in the thickness direction, the present inventor has attempted to develop an optical film provided with a liquid crystal cured layer in which the inclination angle of the molecules of the liquid crystal compound is appropriately adjusted. It was.

Further, in order to exert a desired optical function in a wide wavelength range, it is desired that the retardation film has an in-plane retardation having anti-wavelength dispersibility. Therefore, when a film provided with a liquid crystal curing layer is used as a retardation film, a liquid crystal compound capable of exhibiting birefringence of reverse wavelength dispersibility (hereinafter, may be appropriately referred to as “reverse dispersion liquid crystal compound”) is used. Is desired.

However, in the conventional technique, in order to increase the inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal cured layer, it is necessary to provide an alignment film separately from the liquid crystal cured layer. However, in the alignment film conventionally used, the liquid crystal composition used for forming the liquid crystal cured layer may be repelled by the surface of the alignment film. Normally, the liquid crystal cured layer is not formed at the repelled portion. Further, in the part where the liquid crystal composition is not repelled, the liquid crystal composition tends to gather by the amount of the repelled part, and a liquid crystal cured layer thicker than intended is formed. Therefore, in order to obtain a practical optical film having desired optical characteristics, it is required to suppress the cissing.

The present invention has been devised in view of the above problems, has an in-plane retardation having a reverse wave dispersibility, can be manufactured while suppressing repelling of the inclined layer composition, and has excellent viewing angle characteristics. A liquid crystal oriented layer capable of obtaining an optical film and a method for producing the same; it has an in-plane retardation having a reverse wave dispersion, can be produced while suppressing the repelling of the inclined layer composition, and has excellent viewing angle characteristics. Optical film and its manufacturing method; 1/4 wave plate including the liquid crystal alignment layer or optical film; polarizing plate having the liquid crystal alignment layer or optical film; and organic having the liquid crystal alignment layer or optical film. It is an object of the present invention to provide an electroluminescence display panel;

The present inventor has diligently studied to solve the above-mentioned problems. As a result, the present inventor has a reverse wavelength dispersive in-plane retardation according to a predetermined liquid crystal oriented layer formed of a cured product of the oriented layer composition containing the reverse dispersed liquid crystal compound, and is an inclined layer. The present invention has been completed by finding that an optical film that can be produced while suppressing the repelling of the composition and has excellent viewing angle characteristics can be obtained.
That is, the present invention includes the following.

[1] A liquid crystal alignment layer containing a molecule of the liquid crystal compound formed of a cured product of an alignment layer composition containing a liquid crystal compound capable of expressing birefringence of inverse wavelength dispersibility and having a fixed orientation state.
At least a part of the molecules of the liquid crystal compound contained in the liquid crystal alignment layer are inclined with respect to the layer plane of the liquid crystal alignment layer.
A liquid crystal alignment layer having a surface having a surface free energy of 40 mJ / m ² or more.
[2] The liquid crystal alignment layer according to [1], wherein the substantially maximum inclination angle of the molecule of the liquid crystal compound contained in the liquid crystal alignment layer is 15 ° or more and 60 ° or less.
[3] An inclination containing the liquid crystal alignment layer according to [1] or [2] and a liquid crystal compound capable of exhibiting birefringence having the same or different inverse wavelength dispersibility as the liquid crystal compound contained in the alignment layer composition. A liquid crystal inclined layer formed of a cured product of the layer composition is provided.
An optical film in which the liquid crystal inclined layer is in direct contact with the surface of the liquid crystal alignment layer.
[4] The optical film according to [3], wherein the in-plane retardation of the optical film at a measurement wavelength of 590 nm is 100 nm or more and 180 nm or less.
[5] A step of forming a layer of an oriented layer composition containing a liquid crystal compound capable of expressing birefringence of inverse wavelength dispersibility, and
A step of aligning the liquid crystal compound contained in the layer of the alignment layer composition, and
A step of curing the layer of the alignment layer composition to obtain a liquid crystal alignment layer, and the like.
At least a part of the molecules of the liquid crystal compound contained in the liquid crystal alignment layer are inclined with respect to the layer plane of the liquid crystal alignment layer.
A method for producing a liquid crystal oriented layer, wherein the liquid crystal oriented layer has a surface having a surface free energy of 40 mJ / m ² or more.
[6] Birefringence having the same or different inverse wavelength dispersibility as the liquid crystal compound contained in the alignment layer composition can be directly expressed on the surface of the liquid crystal alignment layer according to [1] or [2]. A step of forming a layer of a gradient layer composition containing a liquid crystal compound, and
A step of orienting the liquid crystal compound contained in the layer of the inclined layer composition, and
A method for producing an optical film, which comprises a step of curing a layer of the inclined layer composition to obtain a liquid crystal inclined layer.
[7] The step of forming the layer of the inclined layer composition directly on the surface of the liquid crystal alignment layer does not apply the rubbing treatment to the surface of the liquid crystal alignment layer, but directly on the surface of the liquid crystal alignment layer. [6] The method for producing an optical film, which comprises forming a layer of the inclined layer composition.
[8] A quarter wave plate comprising the liquid crystal alignment layer according to [1] or [2] or the optical film according to [3] or [4].
[9] A polarizing plate comprising the liquid crystal alignment layer according to [1] or [2] or the optical film according to [3] or [4].
[10] An organic electroluminescence display panel comprising the liquid crystal alignment layer according to [1] or [2] or the optical film according to [3] or [4].

According to the present invention, a liquid crystal orientation which has an in-plane retardation of reverse wave dispersibility, can be produced while suppressing repelling of an inclined layer composition, and can obtain an optical film having excellent viewing angle characteristics. Layer and method for producing the same; an optical film having an in-plane retardation of inverse wave dispersibility, capable of being produced while suppressing repelling of the inclined layer composition, and having excellent viewing angle characteristics; the method for producing the same; A 1/4 wave plate having a liquid crystal alignment layer or an optical film; a polarizing plate having the liquid crystal alignment layer or an optical film; and an organic electroluminescence display panel having the liquid crystal alignment layer or an optical film; can be provided.

FIG. 1 is a cross-sectional view schematically showing a liquid crystal alignment layer according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing an optical film according to an embodiment of the present invention. FIG. 3 is a graph in which the retardation ratio R (θ) / R (0 °) of the liquid crystal alignment layer according to a certain example is plotted against the incident angle θ. FIG. 4 is a perspective view for explaining a measurement direction when measuring the retardation of the liquid crystal alignment layer from the inclination direction.

Hereinafter, the present invention will be described in detail with reference to examples and embodiments. However, the present invention is not limited to the examples and embodiments shown below, and can be arbitrarily modified and implemented without departing from the scope of claims of the present invention and the equivalent scope thereof.

In the following description, the "in-plane direction" of a layer represents a direction parallel to the layer plane unless otherwise specified.

In the following description, the "thickness direction" of a layer represents the direction perpendicular to the layer plane unless otherwise specified. Therefore, unless otherwise specified, the in-plane direction and the thickness direction of a certain layer are perpendicular to each other.

In the following description, the "front direction" of a surface represents the normal direction of the surface, and specifically, the direction of the polar angle of the surface of 0 °, unless otherwise specified.

In the following description, the "tilt direction" of a surface represents a direction that is neither parallel nor perpendicular to the surface, and specifically, the polar angle of the surface is in the range of 5 ° or more and 85 ° or less. Point to the direction of.

In the following description, unless otherwise specified, the birefringence Δn (450) at a wavelength of 450 nm and the birefringence Δn (550) at a wavelength of 550 nm satisfy the following equation (N1), unless otherwise specified. To say. A liquid crystal compound capable of exhibiting such an inverse wavelength-dispersible birefringence can usually exhibit a larger birefringence as the measurement wavelength is longer.
Δn (450) <Δn (550) (N1)

In the following description, unless otherwise specified, birefringence Δn (450) at a wavelength of 450 nm and birefringence Δn (550) at a wavelength of 550 nm satisfy the following equation (N2), unless otherwise specified. To say. A liquid crystal compound capable of exhibiting such forward wavelength dispersive birefringence can usually exhibit smaller birefringence as the measurement wavelength is longer.
Δn (450)> Δn (550) (N2)

In the following description, unless otherwise specified, "(meth) acrylic acid" is a term that includes "acrylic acid", "methacrylic acid" and combinations thereof.

In the following description, the in-plane retardation Re of a certain layer is a value represented by Re = (nx-ny) × d unless otherwise specified. Here, nx represents the refractive index in the direction perpendicular to the thickness direction of the layer (in-plane direction) and in the direction giving the maximum refractive index. ny represents the refractive index in the in-plane direction of the layer and orthogonal to the nx direction. d represents the thickness of the layer. The measurement wavelength of the retardation is 590 nm unless otherwise specified. The in-plane retardation Re can be measured using a phase difference meter (“AxoScan” manufactured by Axometrics).

In the following description, the resin having a positive natural birefringence value means a resin in which the refractive index in the stretching direction is larger than the refractive index in the direction orthogonal to the refractive index. Further, the resin having a negative natural birefringence value means a resin in which the refractive index in the stretching direction is smaller than the refractive index in the direction orthogonal to it. The intrinsic birefringence value can be calculated from the dielectric constant distribution.

In the following description, the direction of the slow phase axis of a certain layer means the direction of the slow phase axis in the in-plane direction unless otherwise specified.

In the following description, the directions of the elements are "parallel" and "vertical", unless otherwise specified, within a range that does not impair the effect of the present invention, for example, ± 4 °, preferably ± 3 °, more preferably ± 1. It may include errors within the range of °.

In the following description, unless otherwise specified, the "tilt angle" of the molecules of the liquid crystal compound contained in a certain layer represents the angle formed by the molecules of the liquid crystal compound with respect to the layer plane, and is also referred to as "tilt angle". Sometimes called. This inclination angle corresponds to the maximum angle among the angles formed by the direction of the maximum refractive index in the refractive index ellipsoid of the molecule of the liquid crystal compound with the layer plane. Further, in the following description, unless otherwise specified, the “inclination angle” represents the inclination angle of the molecule of the liquid crystal compound with respect to the layer plane of the layer containing the liquid crystal compound. The inclination angle with respect to the layer plane may be referred to as "inclination angle with respect to the in-plane direction" parallel to the layer plane.

In the following description, the "substantially maximum tilt angle" of a molecule of a liquid crystal compound contained in a certain layer means that the tilt angle of the molecule on one surface of the layer is 0 ° and the tilt angle of the molecule is the thickness. It refers to the maximum value of the tilt angle of the molecules of the liquid crystal compound, assuming that it changes at a constant rate in the direction. Usually, in a layer containing a liquid crystal compound, the inclination angle of the molecule of the liquid crystal compound is smaller as it is closer to one side of the layer and larger as it is farther from the one side in the thickness direction. The actual maximum tilt angle is calculated on the assumption that the rate of change in the tilt angle in the thickness direction (that is, the rate of change that decreases as it is closer to one side and increases as it is farther from one side) is constant. Represents the maximum value of the tilt angle.

In the following description, the number of carbon atoms of a group having a substituent does not include the number of carbon atoms of the substituent unless otherwise specified. Therefore, for example, in the description of "an alkyl group having 1 to 20 carbon atoms which may have a substituent", the number of carbon atoms of the alkyl group itself which does not include the carbon atom number of the substituent is 1 to 20. Represents that.

[1. Liquid crystal alignment layer]
(1.1. Outline of liquid crystal alignment layer)
FIG. 1 is a cross-sectional view schematically showing a liquid crystal alignment layer 100 according to an embodiment of the present invention. Further, FIG. 2 is a cross-sectional view schematically showing the optical film 200 according to the embodiment of the present invention.
As shown in FIGS. 1 and 2, the liquid crystal alignment layer 100 according to the embodiment of the present invention is a liquid crystal inclined layer 210 formed of a cured product of a liquid crystal composition containing a liquid crystal compound on the liquid crystal alignment layer 100. Is a layer for forming a liquid crystal. The optical film 200 is obtained by a manufacturing method including forming a liquid crystal inclined layer 210 on the liquid crystal alignment layer 100.

Both the liquid crystal alignment layer 100 and the liquid crystal inclined layer 210 correspond to a liquid crystal cured layer as a layer formed of a cured product of a liquid crystal composition containing a liquid crystal compound, but in the present application, for the sake of distinction, "liquid crystal" The "aligned layer" 100 and the "liquid crystal inclined layer" 210 are called separately. Further, in order to distinguish between the liquid crystal composition used for forming the liquid crystal alignment layer 100 and the liquid crystal composition used for forming the liquid crystal inclined layer 210, the liquid crystal composition used for forming the liquid crystal alignment layer 100 is appropriately referred to as "alignment layer". The liquid crystal composition used for forming the liquid crystal inclined layer 210 is referred to as "composition", and is referred to as "inclined layer composition". Further, in the following description, the entire liquid crystal cured layer having a multi-layer structure including the liquid crystal alignment layer 100 and the liquid crystal inclined layer 210 may be referred to as a "composite liquid crystal layer" 220.

The liquid crystal alignment layer 100 is formed of a cured product of the alignment layer composition containing a reverse dispersion liquid crystal compound (that is, a liquid crystal compound capable of exhibiting reverse wavelength dispersive birefringence).

Since it is formed of a cured product of the alignment layer composition, the liquid crystal alignment layer 100 contains molecules of a reverse-dispersion liquid crystal compound whose orientation state is fixed. The term "reverse dispersion liquid crystal compound having a fixed orientation state" includes a polymer of the reverse dispersion liquid crystal compound. Normally, the liquid crystal property of the reverse-dispersed liquid crystal compound is lost by polymerization, but in the present application, the reverse-dispersed liquid crystal compound thus polymerized is also included in the term "reverse-dispersed liquid crystal compound contained in the liquid crystal alignment layer". The liquid crystal alignment layer 100 may contain a molecule of a reverse-dispersion liquid crystal compound whose orientation state is not fixed by combining with a molecule of a reverse-dispersion liquid crystal compound whose orientation state is fixed, but is included in the liquid crystal alignment layer 100. It is preferable that all the molecules of the inversely dispersed liquid crystal compound are fixed in the oriented state.

At least a part of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer 100 are inclined with respect to the layer plane of the liquid crystal alignment layer 100 (that is, with respect to the in-plane direction). When a molecule of a liquid crystal compound is "inclined" with respect to the layer plane (that is, in-plane direction), the inclination angle of the molecule with respect to the layer plane (that is, in-plane direction) is 5 ° or more and 85. Indicates that it is in the range of ° or less. The molecules of such an inclined liquid crystal compound are usually in a state of being neither parallel nor perpendicular to the layer plane (that is, in the in-plane direction).

Further, the liquid crystal alignment layer 100 has a surface 100U having a predetermined range of surface free energy. This surface 100U is hereinafter appropriately referred to as a "specific surface". The specific surface free energy of the specific surface 100U is usually 40 mJ / m ² or more, preferably 40.5 mJ / m ² or more. Since the specific surface 100U has such a large surface free energy, it is possible to suppress the repelling of the inclined layer composition when the layer of the inclined layer composition is formed on the specific surface 100U. Further, when the specific surface 100U has surface free energy in such a range, the inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal inclined layer 210 can be increased. The upper limit of the surface free energy of the specific surface 100U is not particularly limited, but is usually 45 mJ / m ² or less.

In this way, a layer of the inclined layer composition can be formed on the specific surface 100U of the liquid crystal alignment layer 100 while suppressing the generation of cissing. Further, the specific surface 100U of the liquid crystal alignment layer 100 is inclined to the specific surface 100U by containing the inversely dispersed liquid crystal compound in which the molecules are inclined with respect to the layer plane (that is, with respect to the in-plane direction) as described above. When a layer of the layer composition is formed, it has an action of inclining the molecules of the inversely dispersed liquid crystal compound contained in the layer of the inclined layer composition with respect to the layer plane (that is, in the in-plane direction). Therefore, according to the liquid crystal alignment layer 100, the tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal tilt layer 210 formed on the specific surface 100U can be increased, so that the optical film 200 having excellent viewing angle characteristics can be increased. Can be obtained. Further, since both the liquid crystal alignment layer 100 and the liquid crystal inclined layer 210 contain a reverse dispersion liquid crystal compound, the obtained optical film 200 can have an in-plane retardation of reverse wavelength dispersibility. Therefore, by using the liquid crystal alignment layer 100 as described above, it has an in-plane retardation with anti-wavelength dispersibility, can be produced while suppressing the repelling of the inclined layer composition, and has excellent viewing angle characteristics. An optical film 200 can be obtained.

The surface free energy of the specific surface 100U of the liquid crystal alignment layer 100 is obtained from the contact angle of pure water (H ₂ O) and the contact angle of diiodomethane (CH ₂ I ₂ ) on the specific surface 100U based on the theory of Owns-Wendt. Be done.

In Owns-Wendt's theory, the surface free energy is assumed to be divided into a dispersion component d and a hydrogen bond component h. Therefore, the surface free energy γ _L of the liquid is expressed as the sum of the dispersion component γ _L ^d and the hydrogen bond component γ _L ^h , as represented by the following formula (X1). Further, the surface free energy γ _S of the solid is expressed as the sum of the dispersion component γ _S ^d and the hydrogen bond component γ _S ^h , as represented by the following formula (X2). Then, the adhesion work _WLS when the liquid adheres to the solid is expressed by the following formula (X3). Work of adhesion _{W LS} of the, according to the formula of Young-Dupre, using a contact angle θ of the liquid to a solid is expressed by the following formula (X4). Therefore, the following equation (X5) holds. Therefore, by applying the contact angle θ of pure water and diiodomethane, which are liquids in which the dispersion component γ _L ^d of the surface free energy γ _L and the hydrogen bond component γ _L ^h are known, to the equation (X5) and solving the simultaneous equations, The surface free energy of the specific surface 100U corresponding to the surface free energy γ _S of the solid can be obtained.
For the above-mentioned Theory of Owns-Wendt, "DK Owns, RC Wendt, J. Appl. Polymer. Sci., 13, 1741, (1969)" can be referred to.

Examples of the method for adjusting the surface free energy of the specific surface 100U of the liquid crystal alignment layer 100 include the type and amount of the inversely dispersed liquid crystal compound contained in the alignment layer composition, and the surface activity which may be contained in the alignment layer composition. Examples thereof include a method for appropriately adjusting the type and amount of the agent and the thickness of the liquid crystal alignment layer.

(1.2. Reverse dispersion liquid crystal compound)
The inversely dispersed liquid crystal compound is a compound having a liquid crystal property, and is usually a compound capable of exhibiting a liquid crystal phase when the inversely dispersed liquid crystal compound is oriented.

Further, the reverse dispersion liquid crystal compound is a liquid crystal compound capable of exhibiting reverse wavelength dispersive birefringence as described above. Here, the liquid crystal compound capable of expressing the reverse wavelength-dispersible birefringence means that when a layer of the liquid crystal compound is formed and the liquid crystal compound is oriented in the layer, the reverse wavelength-dispersible birefringence is generated. A liquid crystal compound that is expressed. Usually, when a liquid crystal compound is homogenically oriented, the liquid crystal compound exhibits reverse wavelength dispersive birefringence by examining whether or not the layer of the liquid crystal compound exhibits reverse wavelength dispersive birefringence. You can check if you want to. Here, homogenizing the liquid crystal compound means forming a layer containing the liquid crystal compound, and the long axis direction of the mesogen skeleton of the molecule of the liquid crystal compound in the layer is parallel to the plane of the layer. Orienting in one direction. When the liquid crystal compound contains a plurality of types of mesogen skeletons having different orientation directions, the direction in which the longest type of mesogen is oriented is the above-mentioned orientation direction. Further, the birefringence of the layer is obtained from "(in-plane retardation of the layer) ÷ (thickness of the layer)".

The reverse-dispersed liquid crystal compound may be a compound containing a main chain mesogen and a side chain mesogen bonded to the main chain mesogen in the molecule of the back-dispersed liquid crystal compound. The reverse-dispersed liquid crystal compound containing the main chain mesogen and the side chain mesogen can be oriented in a direction different from that of the main chain mesogen when the reverse dispersed liquid crystal compound is oriented. Therefore, in the layer of the inversely dispersed liquid crystal compound thus oriented, the main chain mesogen and the side chain mesogen can be oriented in different directions. In such a case, the birefringence of the layer is expressed as the difference between the refractive index corresponding to the main chain mesogen and the refractive index corresponding to the side chain mesogen, and as a result, the birefringence of inverse wavelength dispersibility can be expressed.

The inversely dispersed liquid crystal compound preferably has polymerizable properties. Therefore, it is preferable that the molecule of the inversely dispersed liquid crystal compound contains a polymerizable group such as an acryloyl group, a methacryloyl group, and an epoxy group. The polymerizable reverse-dispersed liquid crystal compound can be polymerized in a state of exhibiting a liquid crystal phase, and can be a polymer while maintaining the molecular orientation state in the liquid crystal phase. Therefore, it is possible to fix the orientation state of the inversely dispersed liquid crystal compound in the liquid crystal alignment layer, or to increase the degree of polymerization of the liquid crystal compound to increase the mechanical strength of the liquid crystal alignment layer.

The molecular weight of the inversely dispersed liquid crystal compound is preferably 300 or more, more preferably 500 or more, particularly preferably 800 or more, preferably 2000 or less, more preferably 1700 or less, and particularly preferably 1500 or less. By using a inversely dispersed liquid crystal compound having a molecular weight in such a range, the coatability of the oriented layer composition can be particularly improved.

The birefringence Δn of the inversely dispersed liquid crystal compound at the measurement wavelength of 590 nm is preferably 0.01 or more, more preferably 0.03 or more, preferably 0.15 or less, and more preferably 0.10 or less. By using a inversely dispersed liquid crystal compound having a birefringence Δn in such a range, a liquid crystal oriented layer having a large substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound can be easily obtained. Further, usually, by using a inversely dispersed liquid crystal compound having a birefringence Δn in such a range, it is easy to obtain a liquid crystal oriented layer having few orientation defects.

The birefringence of the liquid crystal compound can be measured by, for example, the following method.
A layer of the liquid crystal compound is prepared, and the liquid crystal compound contained in the layer is homogenically oriented. Then, the in-plane retardation of the layer is measured. Then, the birefringence of the liquid crystal compound can be obtained from "(in-plane retardation of the layer) ÷ (thickness of the layer)". At this time, in order to facilitate in-plane retardation and thickness measurement, the homogenically oriented liquid crystal compound layer may be cured.

As the inverse dispersion liquid crystal compound, one kind may be used alone, or two or more kinds may be used in combination at an arbitrary ratio.

Examples of the inversely dispersed liquid crystal compound include those represented by the following formula (I).

In the formula (I), Ar represents a group represented by any of the following formulas (II-1) to (II-7). In formulas (II-1) to (II-7), * represents the bonding position with Z ¹ or Z ² .

In the above formula (II-1) ~ formula (II-7), ^{E 1} and ^{E 2,} each ^{independently, -CR 11 R 12 -, -} S -, - NR 11 -, - CO- and - Represents a group selected from the group consisting of O−. Further, R ¹¹ and R ¹² each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Above all, it is preferable that E ¹ and E ² are independently of −S−.

In the above formulas (II-1) to (II-7), D ^{1 to} D ³ each independently have an aromatic hydrocarbon ring group or a substituent which may have a substituent. Represents an aromatic heterocyclic group that may have. The number of carbon atoms of the group represented by D ^{1 to} D ³ (including the number of carbon atoms of the substituent) is usually 2 to 100 independently of each other.

The number of carbon atoms of the aromatic hydrocarbon ring group in D ^{1 to} D ³ is preferably 6 to 30. Examples of the aromatic hydrocarbon ring group having 6 to 30 carbon atoms in D ^{1 to} D ³ include a phenyl group and a naphthyl group. Among them, a phenyl group is more preferable as the aromatic hydrocarbon ring group.

Examples of the substituent that the aromatic hydrocarbon ring group in D ^{1 to} D ³ can have include a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; a carbon atom such as a methyl group, an ethyl group and a propyl group. Alkyl group of number 1 to 6; alkenyl group having 2 to 6 carbon atoms such as vinyl group and allyl group; alkyl halide group having 1 to 6 carbon atoms such as trifluoromethyl group; dimethylamino group and the like , N, N-dialkylamino group with 1 to 12 carbon atoms; alkoxy group with 1 to 6 carbon atoms such as methoxy group, ethoxy group, isopropoxy group; nitro group; -OCF ₃ ; -C (= O) ) -R ^b ; -OC (= O) -R ^b ; -C (= O) -OR ^b ; -SO ₂ R ^a ; and the like. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

^Ra may have an alkyl group having 1 to 6 carbon atoms; an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms as a substituent, and has 6 carbon atoms. Represents a group selected from the group consisting of ~ 20 aromatic hydrocarbon ring groups;

R ^b may have an alkyl group having 1 to 20 carbon atoms which may have a substituent; an alkenyl group having 2 to 20 carbon atoms which may have a substituent; even if it has a substituent. It represents a group selected from the group consisting of a good cycloalkyl group having 3 to 12 carbon atoms; and an aromatic hydrocarbon ring group having 6 to 12 carbon atoms which may have a substituent.

The number of carbon atoms of the alkyl group having 1 to 20 carbon atoms in R ^b is preferably 1 to 12, and more preferably 4 to 10. Examples of the alkyl group having 1 to 20 carbon atoms in R ^b include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a 1-methylpentyl group, and a 1-ethylpentyl group. , Se-butyl group, t-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group. , N-Undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecil group, and n-icosyl. Butyl group etc. can be mentioned.

Examples of the substituent that the alkyl group having 1 to 20 carbon atoms in ^Rb can have include a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; and a dimethylamino group having 2 to 12 carbon atoms. N, N-dialkylamino group; alkoxy group having 1 to 20 carbon atoms such as methoxy group, ethoxy group, isopropoxy group, butoxy group; methoxymethoxy group, methoxyethoxy group, etc., having 1 to 12 carbon atoms An alkoxy group having 1 to 12 carbon atoms substituted with an alkoxy group; a nitro group; an aromatic hydrocarbon ring group having 6 to 20 carbon atoms such as a phenyl group and a naphthyl group; a triazolyl group, a pyrrolyl group, a furanyl group, Aromatic heterocyclic group having 2 to 20 carbon atoms such as thienyl group, thiazolyl group and benzothiazole-2-ylthio group; cycloalkyl having 3 to 8 carbon atoms such as cyclopropyl group, cyclopentyl group and cyclohexyl group. Group: Cycloalkyloxy group having 3 to 8 carbon atoms such as cyclopentyloxy group and cyclohexyloxy group; Cyclic ether having 2 to 12 carbon atoms such as tetrahydrofuranyl group, tetrahydropyranyl group, dioxolanyl group and dioxanyl group Group; aryloxy group having 6 to 14 carbon atoms such as phenoxy group and naphthoxy group; one or more hydrogen atoms such as trifluoromethyl group, pentafluoroethyl group and -CH ₂ CF ₃ are replaced with fluorine atom. Examples thereof include a fluoroalkyl group having 1 to 12 carbon atoms; a benzofuryl group; a benzopyranyl group; a benzodioxolyl group; and a benzodioxanyl group; The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

The number of carbon atoms of the alkenyl group having 2 to 20 carbon atoms in R ^b is preferably 2 to 12. Examples of the alkenyl group having 2 to 20 carbon atoms in R ^b include a vinyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a decenyl group and an undecenyl group. , Dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, nonadesenyl group, icosenyl group and the like.

Examples of the substituent which may have an alkenyl group having 2 to 20 carbon atoms in R ^b, for example, include the same examples as the substituent group which may have an alkyl group having 1 to 20 carbon atoms in R ^b. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Examples of the cycloalkyl group having 3 to 12 carbon atoms in R ^b include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Of these, as the cycloalkyl group, a cyclopentyl group and a cyclohexyl group are preferable.

Examples of the substituent that the cycloalkyl group having 3 to 12 carbon atoms in ^Rb can have include a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; and a dimethylamino group having 2 to 12 carbon atoms. N, N-dialkylamino group; alkyl group having 1 to 6 carbon atoms such as methyl group, ethyl group, propyl group; alkoxy having 1 to 6 carbon atoms such as methoxy group, ethoxy group, isopropoxy group, etc. Examples thereof include a group; a nitro group; and an aromatic hydrocarbon ring group having 6 to 20 carbon atoms such as a phenyl group and a naphthyl group; Among them, as the substituent of the cycloalkyl group, a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group and a propyl group; a methoxy group and an ethoxy group. An alkoxy group having 1 to 6 carbon atoms such as a group and an isopropoxy group; a nitro group; and an aromatic hydrocarbon ring group having 6 to 20 carbon atoms such as a phenyl group and a naphthyl group; are preferable. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Examples of the aromatic hydrocarbon ring group having 6 to 12 carbon atoms in R ^b include a phenyl group, a 1-naphthyl group, a 2-naphthyl group and the like. Of these, a phenyl group is preferable as the aromatic hydrocarbon ring group.

Examples of the substituent that the aromatic hydrocarbon ring group having 6 to 12 carbon atoms in ^Rb can have include a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; a dimethylamino group and the like. 2 to 12 N, N-dialkylamino groups; alkoxy groups with 1 to 20 carbon atoms such as methoxy group, ethoxy group, isopropoxy group, butoxy group; number of carbon atoms such as methoxymethoxy group and methoxyethoxy group An alkoxy group having 1 to 12 carbon atoms substituted with an alkoxy group of 1 to 12; a nitro group; an aromatic heterocyclic group having 2 to 20 carbon atoms such as a triazolyl group, a pyrrolyl group, a furanyl group and a thiophenyl group; Cycloalkyl group having 3 to 8 carbon atoms such as cyclopropyl group, cyclopentyl group and cyclohexyl group; cycloalkyloxy group having 3 to 8 carbon atoms such as cyclopentyloxy group and cyclohexyloxy group; tetrahydrofuranyl group and tetrahydro Cyclic ether groups having 2 to 12 carbon atoms such as pyranyl group, dioxolanyl group and dioxanyl group; aryloxy groups having 6 to 14 carbon atoms such as phenoxy group and naphthoxy group; trifluoromethyl group and pentafluoroethyl A fluoroalkyl group having 1 to 12 carbon atoms in which one or more hydrogen atoms are substituted with a fluorine atom, such as a group, -CH ₂ CF _3, etc .; -OCF ₃ ; benzofuryl group; benzopyranyl group; benzodioxolyl group; Benzodioxanyl group; etc. Among them, as the substituent of the aromatic hydrocarbon ring group, a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; a methoxy group, an ethoxy group, an isopropoxy group, a butoxy group and the like having 1 to 20 carbon atoms. Alkoxy group; nitro group; aromatic heterocyclic group having 2 to 20 carbon atoms such as furanyl group and thiophenyl group; cycloalkyl group having 3 to 8 carbon atoms such as cyclopropyl group, cyclopentyl group and cyclohexyl group; A fluoroalkyl group having 1 to 12 carbon atoms in which one or more hydrogen atoms are substituted with a fluorine atom, such as a trifluoromethyl group, a pentafluoroethyl group, and -CH ₂ CF ₃ , is preferable; -OCF ₃ ;. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

The number of carbon atoms of the aromatic heterocyclic group in D ^{1 to} D ³ is preferably 2 to 30. Examples of the aromatic heterocyclic group having 2 to 30 carbon atoms in D ^{1 to} D ³ include 1-benzofuranyl group, 2-benzofuranyl group, imidazolyl group, indolinyl group, frazayl group, oxazolyl group, quinolyl group and thiadiazolyl group. , Thiazolyl group, thiazolopyrazinyl group, thiazolopyridyl group, thiazolopyridazinyl group, thiazolopyrimidinyl group, thienyl group, triazinyl group, triazolyl group, naphthyldinyl group, pyrazinyl group, pyrazolyl group, pyranyl group, Pyridyl group, pyridadinyl group, pyrimidinyl group, pyrrolyl group, phthalazinyl group, furanyl group, benzo [c] thienyl group, benzo [b] thienyl group, benzoisooxazolyl group, benzoisothiazolyl group, benzoimidazolyl group, benzooxa Examples thereof include a diazolyl group, a benzoxazolyl group, a benzothiadiazolyl group, a benzothiazolyl group, a benzotriazinyl group, a benzotriazolyl group, a benzopyrazolyl group and the like. Among them, as the aromatic heterocyclic group, a monocyclic aromatic heterocyclic group such as a furanyl group, a pyranyl group, a thienyl group, an oxazolyl group, a frazanyl group, a thiazolyl group, and a thiadiazolyl group; Zolyl group, quinolyl group, 1-benzofuranyl group, 2-benzofuranyl group, phthalimide group, benzo [c] thienyl group, benzo [b] thienyl group, thiazolopyridyl group, thiazolopyrazinyl group, benzoisooxazoli Aromatic heterocyclic groups of fused rings, such as a ru group, a benzoxaziazolyl group, and a benzothiadiazolyl group; are more preferred.

Examples of the substituent which may have an aromatic heterocyclic group in D ¹ to D ^3, for example, include the same examples as the substituent group which may have an aromatic hydrocarbon ring group of D ¹ to D ^3. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

In the above formulas (II-1) to (II-7), D ^{4 to} D ⁵ each independently represent an acyclic group which may have a substituent. D ⁴ and D ⁵ may be combined to form a ring. The number of carbon atoms of the group represented by D ^{4 to} D ⁵ (including the number of carbon atoms of the substituent) is usually 1 to 100 independently of each other.

The number of carbon atoms of the acyclic group in D ^{4 to} D ⁵ is preferably 1 to 13. Examples of the acyclic group in D ^{4 to} D ⁵ include an alkyl group having 1 to 6 carbon atoms; a cyano group; a carboxyl group; a fluoroalkyl group having 1 to 6 carbon atoms; and an alkoxy group having 1 to 6 carbon atoms. -C (= O) -CH ₃ ; -C (= O) NHPh; -C (= O) -OR ^x ; Among them, as the non-cyclic group, a cyano group, a carboxyl _{group, -C (= O) -CH 3} , -C (= O) NHPh, -C (= O) -OC 2 H 5, -C (= O) -OC ₄ H ₉ , -C (= O) -OCH (CH ₃ ) ₂ , -C (= O) -OCH ₂ CH ₂ CH (CH ₃ ) -OCH ₃ , -C (= O) -OCH ₂ CH ₂ C (CH ₃ ) _2- OH and -C (= O) -OCH ₂ CH (CH ₂ CH ₃ ) -C ₄ H ₉ are preferable. The Ph represents a phenyl group. Further, R ^x represents an organic group having 1 to 12 carbon atoms. Specific examples of R ^x include an alkoxy group having 1 to 12 carbon atoms or an alkyl group having 1 to 12 carbon atoms which may be substituted with a hydroxyl group.

Examples of the substituent that the acyclic group in D ^{4 to} D ⁵ can have include the same example as the substituent that the aromatic hydrocarbon ring group in D ^{1 to} D ³ can have. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

When D ⁴ and D ⁵ are combined to form a ring, the above D ⁴ and D ⁵ form an organic group containing a ring. Examples of this organic group include a group represented by the following formula. In the following formula, * represents the position where each organic group is bonded to the carbon to which D ⁴ and D ⁵ are bonded.

R ^* represents an alkyl group having 1 to 3 carbon atoms.
R ^** represents a group selected from the group consisting of an alkyl group having 1 to 3 carbon atoms and a phenyl group which may have a substituent.
R ^*** represents a group selected from the group consisting of an alkyl group having 1 to 3 carbon atoms and a phenyl group which may have a substituent.
R ^*** represents a group selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a hydroxyl group, and −COOR ¹³ . R ¹³ represents an alkyl group having 1 to 3 carbon atoms.
Examples of the substituent that the phenyl group can have include a halogen atom, an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, a hydroxyl group, a carboxyl group, an alkoxy group, an aryloxy group, an acyloxy group, a cyano group and an amino group. Can be mentioned. Of these, as the substituent, a halogen atom, an alkyl group, a cyano group and an alkoxy group are preferable. The number of substituents contained in the phenyl group may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

In the above formulas (II-1) to (II-7), D ⁶ is -C (R ^f ) = N-N (R ^g ) R ^h , -C (R ^f ) = N-N = C. ^(R g) ^{R h,} and ^represents a group selected from the group consisting of -C (R f) = N- N = R i. The number of carbon atoms of the group represented by D ⁶ (including the number of carbon atoms of the substituent) is usually 3 to 100.

R ^f represents a group selected from the group consisting of a hydrogen atom; and an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, and an isopropyl group.

R ^g represents a group selected from the group consisting of a hydrogen atom; and an organic group having 1 to 30 carbon atoms which may have a substituent.

Examples of the organic group having 1 to 30 carbon atoms which may have a substituent in R ^g include an alkyl group having 1 to 20 carbon atoms which may have a substituent; At least one of -CH _2- contained in the alkyl group of 20 is -O-, -S-, -OC (= O)-, -C (= O) -O-, or -C (=). O) -Substituent group (except when two or more -O- or -S- are adjacent to each other); an alkenyl group having 2 to 20 carbon atoms which may have a substituent. An alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 12 carbon atoms which may have a substituent; a carbon which may have a substituent. Aromatic hydrocarbon ring group having 6 to 30 atoms; Aromatic heterocyclic group having 2 to 30 carbon atoms which may have a substituent; -SO ₂ ^Ra ; -C (= O) -R ^b ; -CS-NH-R ^b ; can be mentioned. The meanings of R ^a and R ^b are as described above.

The preferred range and examples of the number of carbon atoms of the alkyl group having 1 to 20 carbon atoms in R ^g is the same as that of the alkyl group having 1 to 20 carbon atoms in R ^b .

Examples of the substituent which may have an alkyl group having 1 to 20 carbon atoms in R ^g, for example, fluorine atom, such as chlorine atom, a halogen atom; a cyano group; such as dimethylamino group, having 2 to 12 carbon atoms N, N-dialkylamino group; alkoxy group having 1 to 20 carbon atoms such as methoxy group, ethoxy group, isopropoxy group, butoxy group; methoxymethoxy group, methoxyethoxy group, etc., having 1 to 12 carbon atoms An alkoxy group having 1 to 12 carbon atoms substituted with an alkoxy group; a nitro group; an aromatic hydrocarbon ring group having 6 to 20 carbon atoms such as a phenyl group and a naphthyl group; a triazolyl group, a pyrrolyl group, a furanyl group, Aromatic heterocyclic group having 2 to 20 carbon atoms such as thiophenyl group; cycloalkyl group having 3 to 8 carbon atoms such as cyclopropyl group, cyclopentyl group and cyclohexyl group; cyclopentyloxy group, cyclohexyloxy group and the like , Cycloalkyloxy group with 3 to 8 carbon atoms; cyclic ether group with 2 to 12 carbon atoms such as tetrahydrofuranyl group, tetrahydropyranyl group, dioxolanyl group, dioxanyl group; carbon such as phenoxy group and naphthoxy group. An aryloxy group having 6 to 14 atoms; a fluoroacyl group having 1 to 12 carbon atoms in which one or more hydrogen atoms are replaced with a fluorine atom; a benzofuryl group; a benzopyranyl group; a benzodioxolyl group; a benzodioxanyl Groups; -SO ₂ R ^a ; -SR ^b ; alkoxy groups having 1 to 12 carbon atoms substituted with -SR ^b ; hydroxyl groups; and the like. The meanings of R ^a and R ^b are as described above. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

The preferred range of carbon atoms and examples of the alkenyl group having 2 to 20 carbon atoms in R ^g is the same as that of the alkenyl group having 2 to 20 carbon atoms in R ^b .

Examples of the substituent which may have an alkenyl group having 2 to 20 carbon atoms in R ^g, for example, include the same examples as the substituent group which may have an alkyl group having 1 to 20 carbon atoms in R ^g. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

The alkynyl group having 2 to 20 carbon atoms in R ^g, for example, ethynyl group, propynyl group, 2-propynyl group (propargyl group), butynyl, 2-butynyl, 3-butynyl group, pentynyl group, 2- Examples thereof include a pentynyl group, a hexynyl group, a 5-hexynyl group, a heptynyl group, an octynyl group, a 2-octynyl group, a nonanyl group, a decanyl group and a 7-decanyl group.

Examples of the substituent which may have an alkynyl group having 2 to 20 carbon atoms in R ^g, for example, include the same examples as the substituent group which may have an alkyl group having 1 to 20 carbon atoms in R ^g. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Examples of the cycloalkyl group having 3 to 12 carbon atoms in R ^g include the same example as the cycloalkyl group having 3 to 12 carbon atoms in R ^b .

Examples of the substituent which may have a cycloalkyl group having 3 to 12 carbon atoms in R ^g, for example, include the same examples as the substituent group which may have an alkyl group having 1 to 20 carbon atoms in R ^g. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Examples of the aromatic hydrocarbon ring group having 6 to 30 carbon atoms in R ^g include the same examples as the aromatic hydrocarbon ring group having 6 to 30 carbon atoms in D ^{1 to} D ³ .

Examples of the substituent which may have an aromatic hydrocarbon ring group having 6 to 30 carbon atoms in R ^g, for example, include the same examples as the substituent group which may have an aromatic hydrocarbon ring group of D ¹ to D ³ Be done. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Examples of the aromatic heterocyclic group having 2 to 30 carbon atoms in R ^g include the same examples as the aromatic heterocyclic group having 2 to 30 carbon atoms in D ^{1 to} D ³ .

Examples of the substituent which may have an aromatic heterocyclic group having 2 to 30 carbon atoms in R ^g, for example, include the same examples as the substituent group which may have an aromatic hydrocarbon ring group of D ¹ to D ³ .. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Among those described above, as R ^g , at least one of an alkyl group having 1 to 20 carbon atoms which may have a substituent; and −CH ₂ − contained in the alkyl group having 1 to 20 carbon atoms is used. A group substituted with −O−, −S−, −OC (= O) −, −C (= O) −O−, or −C (= O) − (where −O− or − (Except when two or more S- are adjacent to each other); a cycloalkyl group having 3 to 12 carbon atoms which may have a substituent; and 6 to 6 carbon atoms which may have a substituent. 30 aromatic hydrocarbon ring groups; and aromatic heterocyclic groups having 2 to 30 carbon atoms which may have substituents; are preferable. Among them, as R ^g , at least one of an alkyl group having 1 to 20 carbon atoms which may have a substituent; and −CH ₂ − contained in the alkyl group having 1 to 20 carbon atoms is included. A group substituted with −O−, −S−, −OC (= O) −, −C (= O) −O−, or −C (= O) − (where −O− or − (Except when two or more S- are adjacent to each other); is particularly preferable.

R ^h represents an organic group having one or more aromatic rings selected from the group consisting of an aromatic hydrocarbon ring having 6 to 30 carbon atoms and an aromatic heterocycle having 2 to 30 carbon atoms.

Preferred examples of R ^h include (1) a hydrocarbon ring group having 6 to 40 carbon atoms and having an aromatic hydrocarbon ring having 1 or more carbon atoms and 6 to 30 carbon atoms. The hydrocarbon ring group having this aromatic hydrocarbon ring may be appropriately referred to as "(1) hydrocarbon ring group" below. (1) Specific examples of the hydrocarbon ring group include the following groups.

(1) The hydrocarbon ring group may have a substituent. (1) Examples of the substituent that the hydrocarbon ring group can have include a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; a methyl group, an ethyl group, a propyl group and the like, which have 1 to 6 carbon atoms. Alkyl group; alkenyl group having 2 to 6 carbon atoms such as vinyl group and allyl group; alkyl halide group having 1 to 6 carbon atoms such as trifluoromethyl group; dimethylamino group and the like having 2 carbon atoms ~ 12 N, N-dialkylamino groups; alkoxy groups with 1 to 6 carbon atoms such as methoxy group, ethoxy group, isopropoxy group; nitro group; phenyl group, naphthyl group, etc., 6 to 20 carbon atoms Aromatic hydrocarbon ring group of; -OCF ₃ ; -C (= O) -R ^b ; -OC (= O) -R ^b ; -C (= O) -OR ^b ; -SO ₂ R ^a ; and the like. The meanings of R ^a and R ^b are as described above. Among these, halogen atoms, cyano groups, alkyl groups having 1 to 6 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms are preferable. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Another preferred example of R ^h is (2) having one or more aromatic rings selected from the group consisting of an aromatic hydrocarbon ring having 6 to 30 carbon atoms and an aromatic heterocycle having 2 to 30 carbon atoms. , Heterocyclic groups having 2 to 40 carbon atoms can be mentioned. The heterocyclic group having this aromatic ring may be appropriately referred to as "(2) heterocyclic group" below. (2) Specific examples of the heterocyclic group include the following groups. R independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

(2) The heterocyclic group may have a substituent. Examples of the substituent (2) that the heterocyclic group can have include the same examples as the substituent that (1) the hydrocarbon ring group can have. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Yet another preferred example of R ^h is (3) one or more groups selected from the group consisting of an aromatic hydrocarbon ring group having 6 to 30 carbon atoms and an aromatic heterocyclic group having 2 to 30 carbon atoms. Examples thereof include an alkyl group having 1 to 12 carbon atoms substituted with. Hereinafter, the substituted alkyl group may be appropriately referred to as "(3) substituted alkyl group".

(3) Examples of the "alkyl group having 1 to 12 carbon atoms" in the substituted alkyl group include a methyl group, an ethyl group, a propyl group and an isopropyl group.
(3) As the "aromatic hydrocarbon ring group having 6 to 30 carbon atoms" in the substituted alkyl group, for example, the same example as the aromatic hydrocarbon ring group having 6 to 30 carbon atoms in D ^{1 to} D ³ can be used. Can be mentioned.
(3) Examples of the "aromatic heterocyclic group having 2 to 30 carbon atoms" in the substituted alkyl group include the same examples as the aromatic heterocyclic group having 2 to 30 carbon atoms in D ^{1 to} D ³ . ..

(3) The substituted alkyl group may further have a substituent. Examples of the substituent that the (3) substituted alkyl group can have include the same examples as the substituent that the (1) hydrocarbon ring group can have. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Yet another preferred example of R ^h is (4) one or more groups selected from the group consisting of an aromatic hydrocarbon ring group having 6 to 30 carbon atoms and an aromatic heterocyclic group having 2 to 30 carbon atoms. Examples thereof include an alkenyl group having 2 to 12 carbon atoms substituted with. Hereinafter, the substituted alkenyl group may be appropriately referred to as "(4) substituted alkenyl group".

(4) Examples of the "alkenyl group having 2 to 12 carbon atoms" in the substituted alkenyl group include a vinyl group and an allyl group.
(4) As the "aromatic hydrocarbon ring group having 6 to 30 carbon atoms" in the substituted alkenyl group, for example, the same example as the aromatic hydrocarbon ring group having 6 to 30 carbon atoms in D ^{1 to} D ³ can be used. Can be mentioned.
(4) Examples of the "aromatic heterocyclic group having 2 to 30 carbon atoms" in the substituted alkenyl group include the same examples as the aromatic heterocyclic group having 2 to 30 carbon atoms in D ^{1 to} D ³ . ..

(4) The substituted alkenyl group may further have a substituent. Examples of the substituent that the (4) substituted alkenyl group can have include the same examples as the substituent that the (1) hydrocarbon ring group can have. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Yet another preferred example of R ^h is (5) one or more groups selected from the group consisting of an aromatic hydrocarbon ring group having 6 to 30 carbon atoms and an aromatic heterocyclic group having 2 to 30 carbon atoms. Examples thereof include an alkynyl group having 2 to 12 carbon atoms substituted with. The substituted alkynyl group may be hereinafter appropriately referred to as "(5) substituted alkynyl group".

(5) Examples of the "alkynyl group having 2 to 12 carbon atoms" in the substituted alkynyl group include an ethynyl group and a propynyl group.
(5) As the "aromatic hydrocarbon ring group having 6 to 30 carbon atoms" in the substituted alkynyl group, for example, the same example as the aromatic hydrocarbon ring group having 6 to 30 carbon atoms in D ^{1 to} D ³ can be used. Can be mentioned.
(5) Examples of the "aromatic heterocyclic group having 2 to 30 carbon atoms" in the substituted alkynyl group include the same examples as the aromatic heterocyclic group having 2 to 30 carbon atoms in D ^{1 to} D ³ . ..

(5) The substituted alkynyl group may further have a substituent. Examples of the substituent that the (5) substituted alkynyl group can have include the same examples as the substituent that the (1) hydrocarbon ring group can have. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Preferred specific examples of R ^h include the following groups.

More preferable specific examples of R ^h include the following groups.

Specific examples of R ^h being particularly preferable include the following groups.

The specific example of R ^h described above may further have a substituent. Examples of the substituent include a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group and a propyl group; a vinyl group and an allyl group. , An alkenyl group having 2 to 6 carbon atoms; an alkyl halide group having 1 to 6 carbon atoms such as a trifluoromethyl group; an N, N-dialkylamino group having 2 to 12 carbon atoms such as a dimethylamino group. An alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an ethoxy group, and an isopropoxy group; a nitro group; -OCF ₃ ; -C (= O) -R ^b ; -OC (= O) -R ^b ; -C (= O) -OR ^b ; -SO ₂ R ^a ; and the like. The meanings of R ^a and R ^b are as described above. Among these, halogen atoms, cyano groups, alkyl groups having 1 to 6 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms are preferable. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

R ⁱ has one or more aromatic ring selected from the group consisting of aromatic heterocyclic aromatic hydrocarbon ring and 2 to 30 carbon atoms of 6 to 30 carbon atoms, represents an organic group.

Preferred examples of R ⁱ may have one or more aromatic hydrocarbon ring having 6 to 30 carbon atoms, and a hydrocarbon ring group having 6 to 40 carbon atoms.
As another preferred example of R ⁱ has one or more aromatic ring selected from the group consisting of aromatic heterocyclic aromatic hydrocarbon ring and 2 to 30 carbon atoms of 6 to 30 carbon atoms, Heterocyclic groups having 2 to 40 carbon atoms can be mentioned.

Particularly preferred specific examples of R ⁱ include the following groups. The meaning of R is as described above.

The group represented by any of the formulas (II-1) to (II-7) may have a substituent other than D ^{1 to} D ⁶ . Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 6 carbon atoms, an alkyl halide group having 1 to 6 carbon atoms, and an N-alkylamino having 1 to 6 carbon atoms. Group, N, N-dialkylamino group with 2 to 12 carbon atoms, alkoxy group with 1 to 6 carbon atoms, alkylsulfinyl group with 1 to 6 carbon atoms, carboxyl group, thioalkyl group with 1 to 6 carbon atoms , N-alkylsulfamoyl group having 1 to 6 carbon atoms and N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Preferred examples of Ar in the formula (I) include groups represented by the following formulas (III-1) to (III-10). Further, the groups represented by the formulas (III-1) to (III-10) may have an alkyl group having 1 to 6 carbon atoms as a substituent. In the following formula, * represents the bond position.

Particularly preferable specific examples of the formula (III-1) and the formula (III-4) include the following groups. In the following formula, * represents the bond position.

In the formula (I), ^{Z 1} and ^{Z 2} are each independently a single _{bond, -O -, - O-CH} 2 -, - CH 2 -O -, - O-CH 2 -CH 2 -, - _{CH 2 -CH 2 -O -, -} C (= O) -O -, - O-C (= O) -, - C (= O) -S -, - S-C (= O) -, - _{^{NR 21 -C (= O) -}} , - C (= O) -NR 21 -, - CF 2 -O -, - O-CF 2 -, - CH 2 -CH 2 -, - CF 2 -CF 2 - _{, -O-CH 2 -CH 2 -O} -, - CH = CH-C (= O) -O -, - O-C (= O) -CH = CH -, - CH 2 -C (= O) _{-O -, - O-C (} = O) -CH 2 -, - CH 2 -O-C (= O) -, - C (= O) -O-CH 2 -, - CH 2 -CH 2 - _{C (= O) -O -,} - O-C (= O) -CH 2 -CH 2 -, - CH 2 -CH 2 -O-C (= O) -, - C (= O) -O- _{CH 2 -CH 2 -, - CH} = CH -, - N = CH -, - CH = N -, - N = C (CH 3) -, - C (CH 3) = N -, - N = N- , And -C≡C-, which is selected from the group consisting of. R ²¹ independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the formula (I), A ¹ , A ² , B ¹ and B ² independently have a cyclic aliphatic group which may have a substituent and an aromatic which may have a substituent. Represents a group selected from the group consisting of family groups. The number of carbon atoms of the group represented by A ¹ , A ² , B ¹ and B ² (including the number of carbon atoms of the substituent) is usually 3 to 100 independently of each other. Among them, A ¹ , A ² , B ¹ and B ² each independently have a cyclic aliphatic group having 5 to 20 carbon atoms or a substituent which may have a substituent. Aromatic groups having 2 to 20 carbon atoms are preferable.

Examples of the cyclic aliphatic group in A ¹ , A ² , B ¹ and B ² include cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, and 1,4-cycloheptane-1,4. Cycloalkandyl group having 5 to 20 carbon atoms such as −diyl group, cyclooctane-1,5-diyl group; decahydronaphthalene-1,5-diyl group, decahydronaphthalene-2,6-diyl group, etc. , A bicycloalkandyl group having 5 to 20 carbon atoms; and the like. Of these, a cycloalkandyl group having 5 to 20 carbon atoms which may be substituted is preferable, a cyclohexanediyl group is more preferable, and a cyclohexane-1,4-diyl group is particularly preferable. The cyclic aliphatic group may be a trans form, a cis form, or a mixture of a cis form and a trans form. Among them, the transformer body is more preferable.

Examples of the substituent that the cyclic aliphatic group in A ¹ , A ² , B ¹ and B ² can have include a halogen atom, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Examples include a nitro group and a cyano group. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

Examples of the aromatic group in A ¹ , A ² , B ¹ and B ² include 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, 1,4-naphthylene group, 1, Aromatic hydrocarbon ring groups with 6 to 20 carbon atoms such as 5-naphthylene group, 2,6-naphthylene group, 4,4'-biphenylene group; furan-2,5-diyl group, thiophene-2,5 -Aromatic heterocyclic groups having 2 to 20 carbon atoms such as a diyl group, a pyridine-2,5-diyl group, and a pyrazine-2,5-diyl group; and the like. Among them, an aromatic hydrocarbon ring group having 6 to 20 carbon atoms is preferable, a phenylene group is more preferable, and a 1,4-phenylene group is particularly preferable.

A ^1, as the ^A 2, ^{B 1} and substituents aromatic group may have at ^{B 2,} for ^{example, A 1, A 2, B} 1 and the same as the substituent which may have a cyclic aliphatic group in ^{B 2} For example. The number of substituents may be one or plural. Further, the plurality of substituents may be the same as each other or may be different from each other.

In the formula (I), Y ^{1 to} Y ⁴ are independently single-bonded, -O-, -C (= O)-, -C (= O) -O-, -OC (= O). ^{) -, - NR 22 -C (} = O) -, - C (= O) -NR 22 -, - O-C (= O) -O -, - NR 22 -C (= O) -O-, It represents any one selected from the group consisting of −O—C (= O) −NR ²² − and −NR ²² −C (= O) −NR ²³ −. R ²² and R ²³ independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the formula (I), G ¹ and G ² are independent aliphatic hydrocarbon groups having 1 to 20 carbon atoms; and methylene groups contained in the aliphatic hydrocarbon groups having 3 to 20 carbon atoms. Represents an organic group selected from the group consisting of a group in which one or more of (-CH _2- ) is substituted with -O- or -C (= O)-. The hydrogen atom contained in the organic group of G ¹ and G ² may be substituted with an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen atom. However, the methylene groups (-CH _2- ) at both ends of G ¹ and G ² are not replaced with -O- or -C (= O)-.

Specific examples of the aliphatic hydrocarbon group having 1 to 20 carbon atoms in G ¹ and G ² include an alkylene group having 1 to 20 carbon atoms.

Specific examples of the aliphatic hydrocarbon group having 3 to 20 carbon atoms in G ¹ and G ² include an alkylene group having 3 to 20 carbon atoms.

In formula (I), P ¹ and P ² each independently represent a polymerizable group. Examples of the polymerizable group in P ¹ and P ² include acryloyloxy group, methacryloyloxy group and the like represented by CH ₂ = CR ^31- C (= O) -O-; vinyl group; vinyl ether group; p-Stilben group; acryloyl group; methacryloyl group; carboxyl group; methylcarbonyl group; hydroxyl group; amide group; alkylamino group having 1 to 4 carbon atoms; amino group; epoxy group; oxetanyl group; aldehyde group; isocyanate group; thio Isocyanate group; etc. R ³¹ represents a hydrogen atom, a methyl group, or a chlorine atom. Among them, the group represented by CH ₂ = CR ^31- C (= O) -O- is preferable, CH ₂ = CH-C (= O) -O- (acryloyloxy group), CH ₂ = C (CH _3). ) -C (= O) -O- (methacryloyloxy group) is more preferable, and acryloyloxy group is particularly preferable.

In formula (I), p and q independently represent 0 or 1, respectively.

The inversely dispersed liquid crystal compound represented by the formula (I) can be produced, for example, by the reaction of the hydrazine compound and the carbonyl compound described in International Publication No. 2012/147904.

(1.3. Orientation layer composition)
The oriented layer composition contains the above-mentioned inversely dispersed liquid crystal compound, and may further contain any component if necessary. As the arbitrary component, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.

Since the oriented layer composition can usually be cured by polymerization, the oriented layer composition contains a polymerization initiator as an optional component. The type of the polymerization initiator can be selected according to the type of the polymerizable compound contained in the alignment layer composition. For example, if the polymerizable compound is radically polymerizable, a radical polymerization initiator can be used. If the polymerizable compound is anionically polymerizable, an anionic polymerization initiator may be used. Further, if the polymerizable compound is cationically polymerizable, a cationic polymerization initiator can be used. As the polymerization initiator, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.

The amount of the polymerization initiator is preferably 0.1 part by weight or more, more preferably 0.5 part by weight or more, preferably 30 parts by weight or less, more preferably more preferably, with respect to 100 parts by weight of the reverse dispersion liquid crystal compound. It is 10 parts by weight or less. When the amount of the polymerization initiator is within the above range, the polymerization can proceed efficiently.

The oriented layer composition may contain a surfactant as an arbitrary component. In particular, from the viewpoint of stably obtaining a desired liquid crystal alignment layer, as the surfactant, a surfactant containing a fluorine atom in the molecule is preferable. In the following description, a surfactant containing a fluorine atom in the molecule may be appropriately referred to as a "fluorine-based surfactant".

The fluorine-based surfactant is preferably a nonionic surfactant. When the fluorine-based surfactant is a nonionic surfactant that does not contain an ionic group, the surface state and orientation of the liquid crystal alignment layer can be particularly improved.

The fluorine-based surfactant does not have to have polymerizability and may have polymerizability. Since the polymerizable fluorine-based surfactant can be polymerized in the step of curing the layer of the alignment layer composition, it is usually contained in a part of the molecule of the polymer in the liquid crystal alignment layer.

Examples of the fluorine-based surfactant include AGC Seimi Chemical's Surflon series (S420, etc.), Neos's Futergent series (251, FTX-212M, FTX-215M, FTX-209, etc.), and DIC. Examples include the Mega Fvck series made by F-444. Further, one type of fluorine-based surfactant may be used alone, or two or more types may be used in combination at an arbitrary ratio.

The amount of the surfactant is preferably 0.03 parts by weight or more, more preferably 0.05 parts by weight or more, and preferably 0.40 parts by weight or less, based on 100 parts by weight of the inverse dispersion liquid crystal compound. It is preferably 0.30 parts by weight or less, more preferably 0.25 parts by weight or less. When the amount of the surfactant is in the above range, the substantially maximum inclination angle of the molecule of the inversely dispersed liquid crystal compound in the liquid crystal alignment layer can be effectively increased. Further, when the amount of the surfactant is in the above range, the surface free energy of the specific surface of the liquid crystal alignment layer can be easily contained in a suitable range.

The oriented layer composition may contain a solvent as an arbitrary component. As the solvent, a solvent capable of dissolving the reverse dispersion liquid crystal compound is preferable. As such a solvent, an organic solvent is usually used. Examples of organic solvents include ketone solvents such as cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone and methyl isobutyl ketone; acetate solvents such as butyl acetate and amyl acetate; halogenated hydrocarbon solvents such as chloroform, dichloromethane and dichloroethane; 1 , 4-Dioxane, cyclopentylmethyl ether, tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 1,2-dimethoxyethane and other ether solvents; and aromatic hydrocarbon solvents such as toluene, xylene and mesitylene; Further, one type of solvent may be used alone, or two or more types may be used in combination at an arbitrary ratio.

The boiling point of the solvent is preferably 60 ° C. to 250 ° C., more preferably 60 ° C. to 150 ° C. from the viewpoint of excellent handleability.

The amount of the solvent is preferably 200 parts by weight or more, more preferably 250 parts by weight or more, particularly preferably 300 parts by weight or more, and preferably 650 parts by weight or less, based on 100 parts by weight of the inversely dispersed liquid crystal compound. It is preferably 550 parts by weight or less, and particularly preferably 450 parts by weight or less. By setting the amount of the solvent to the lower limit of the above range or more, the generation of foreign matter can be suppressed, and by setting the amount to the upper limit of the range or less, the drying load can be reduced.

Further, in the alignment layer composition, in order to increase the inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer, the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound is increased as an arbitrary component. It may contain a tilting action component capable of exerting such an action. Many reverse-dispersed liquid crystal compounds can obtain a small tilt angle even if they are oriented by themselves, but by using a tilting component, the tilt of the molecule of the reverse-dispersed liquid crystal compound is promoted to reverse disperse. A liquid crystal oriented layer having a large inclination angle of the molecules of the liquid crystal compound can be easily obtained. However, since it is possible to promote the tilting of the molecules of the inversely dispersed liquid crystal compound by adjusting the operation or conditions in the process of producing the liquid crystal alignment layer, it is not always necessary to use the tilting action component.

Examples of the tilting action component include forward-dispersed liquid crystal compounds having a tilting orientation. Here, the "forward-dispersed liquid crystal compound" refers to a liquid crystal compound capable of exhibiting forward wavelength-dispersible birefringence. Further, the "forward-dispersed liquid crystal compound having a gradient orientation" is a test in which a composition containing a forward-dispersed liquid crystal compound alone as a liquid crystal compound is applied to a rubbing-treated surface of a resin film and subjected to an orientation treatment. A forward-dispersed liquid crystal compound in which, when a layer is obtained, the substantially maximum inclination angle formed by the molecules of the forward-dispersed liquid crystal compound in the test layer with respect to the layer plane can be 30 ° or more. The forward-dispersed liquid crystal compound having a gradient orientation as described above is a reverse-dispersed liquid crystal compound contained in the liquid crystal oriented layer when used in combination with a fluorine-based surfactant having a log P of 4.8 or more and 6.7 or less. It can exert the effect of increasing the substantial maximum tilt angle of the molecule.

Here, "logP" refers to a 1-octanol / water partition coefficient. The logP of the fluorine-based surfactant can be measured by the following measuring method.
A sample solution containing 1% by weight of a fluorine-based surfactant was prepared, and HPLC / ELSD was prepared by a method generally compliant with JIS 7260-117: 2006 {Partition coefficient (1-octanol / water) measurement-high performance liquid chromatography}. Analysis (high performance liquid chromatography / evaporation light scattering detection analysis) is performed to measure the elution time (rt). On the other hand, the labeled compound described in JIS 7260-117: 2006, which has a known logP value, was subjected to HPLC / ELSD analysis in the same manner as in the above-mentioned fluorine-based surfactant, and the elution time (rt) was determined. taking measurement. Based on the measurement results of the labeled compound, a calibration curve showing the relationship between the elution time and logP is prepared. Then, the elution time measured for the fluorine-based surfactant is applied to the calibration curve to determine the logP of the fluorine-based surfactant.

Examples of the forward-dispersed liquid crystal compound having a gradient orientation include the following compounds. Further, for an oriented layer composition containing a forward-dispersed liquid crystal compound having a gradient orientation, the description in JP-A-2018-162379 and Japanese Patent Application Laid-Open No. 2017-060154 may be referred to.

The amount of the forward-dispersed liquid crystal compound having the inclined orientation is preferably 1 part by weight or more, more preferably 1 part by weight or more, based on 100 parts by weight of the total of the reverse-dispersed liquid crystal compound and the forward-dispersed liquid crystal compound having the inclined orientation. It is 5 parts by weight or more, more preferably 10 parts by weight or more, preferably 25 parts by weight or less, and more preferably 20 parts by weight or less. By using a forward-dispersed liquid crystal compound having such an amount of tilt orientation, it is possible to easily obtain a liquid crystal alignment layer having a large substantially maximum tilt angle of the molecule of the reverse dispersion liquid crystal compound and few orientation defects. Can be done.

Examples of the tilting action component include (meth) acrylic acid ester compounds in which the ratio Mw / Np of the molecular weight Mw to the number of π electrons Np is 17 or more and 70 or less. The ratio Mw / Np of the molecular weight Mw of this (meth) acrylic acid ester compound to the number of π electrons Np is usually 17 or more, preferably 23 or more, and usually 70 or less, preferably 50 or less. When this (meth) acrylic acid ester compound is used in combination with a fluorine-based surfactant, it can exert an effect of increasing the substantially maximum inclination angle of the molecule of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer.

The number of π electrons per molecule of a compound is determined based on the type and number of unsaturated bonds contained in the compound. To give an example of the number of π electrons contained in each unsaturated bond, the number of π electrons contained in an aliphatic or aromatic carbon-carbon double bond (C = C) is two, and a carbon-carbon triple bond. The number of π electrons contained in (C≡C) is 4, the number of π electrons contained in the carbon-nitrogen double bond (C = N) is 2, and the number of π electrons contained in the carbon-nitrogen triple bond (C≡N) is π. The number of electrons is 4, and the number of π electrons contained in the nitrogen-nitrogen double bond (N = N) is 2.

Examples of the (meth) acrylic acid ester compound include the following. Further, for the orientation layer composition containing the (meth) acrylic acid ester compound, the description of International Publication No. 2018/173778 and Japanese Patent Application No. 2017-060122 may be referred to.

The amount of the (meth) acrylic acid ester compound is preferably 1 part by weight or more, more preferably 5 parts by weight or more, based on 100 parts by weight of the total of the inverse dispersion liquid crystal compound and the (meth) acrylic acid ester compound. Yes, preferably 30 parts by weight or less, more preferably 20 parts by weight or less. By keeping the amount of the (meth) acrylic acid ester compound within the above range, it is possible to exert an effect of increasing the substantially maximum inclination angle of the molecule of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer.

Further, when the above-mentioned (meth) acrylic acid ester compound is used, it is preferable that the amount of the fluorine-based surfactant is within a predetermined range. Specifically, the amount of the fluorine-based surfactant is preferably 0.11 part by weight or more, more preferably 0.% by weight, based on 100 parts by weight of the total of the inverse dispersion liquid crystal compound and the (meth) acrylic acid ester compound. It is 12 parts by weight or more, preferably 0.29 parts by weight or less, more preferably 0.25 parts by weight or less, and particularly preferably 0.20 parts by weight or less. When the amount of the fluorine-based surfactant is in the above range, it is possible to easily obtain a liquid crystal oriented layer having a large substantially maximum inclination angle of the molecule of the inversely dispersed liquid crystal compound and having few orientation defects.

Examples of the tilting action component include liquid crystal compounds having magnetic field responsiveness. Here, the "liquid crystal compound having magnetic field responsiveness" is a liquid crystal compound whose orientation state can be changed by the magnetic field when a magnetic field is applied at the liquefaction temperature. The alignment layer composition containing the liquid crystal compound having magnetic field responsiveness is subjected to an appropriate magnetic field during the alignment treatment, so that the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer is obtained. Can exert the effect of increasing.

Examples of the liquid crystal compound having magnetic field responsiveness include the following. Further, for the orientation layer composition containing a liquid crystal compound having magnetic field responsiveness, the description in JP-A-2018-163218 and Japanese Patent Application Laid-Open No. 2017-059327 may be referred to.

The amount of the liquid crystal compound having magnetic field responsiveness is preferably 0.1 part by weight or more, more preferably 1 part by weight, based on 100 parts by weight of the total of the liquid crystal compound having magnetic field responsiveness and the inversely dispersed liquid crystal compound. More than parts, particularly preferably 3 parts by weight or more, preferably 40 parts by weight or less, more preferably 30 parts by weight or less, and particularly preferably 20 parts by weight or less. By keeping the amount of the liquid crystal compound having magnetic field responsiveness within the above range, it is possible to easily obtain a liquid crystal alignment layer having a large substantially maximum inclination angle of the molecule of the inversely dispersed liquid crystal compound and having few orientation defects. it can.

Other optional components that the oriented layer composition may contain include, for example, metals; metal complexes; metal oxides such as titanium oxide; colorants such as dyes and pigments; light emitting materials such as fluorescent materials and phosphorescent materials; leveling agents. Examples include thixo agents; gelling agents; polysaccharides; ultraviolet absorbers; infrared absorbers; antioxidants; ion exchange resins; and the like. The amount of these components may be 0.1 parts by weight to 20 parts by weight, respectively, with respect to 100 parts by weight of the total of the inversely dispersed liquid crystal compounds.

(1.4. Characteristics of liquid crystal alignment layer)
The liquid crystal alignment layer is a layer of a cured product obtained by curing the above-mentioned alignment layer composition. Curing of the oriented layer composition is usually achieved by polymerization of the polymerizable compound contained in the oriented layer composition. Therefore, the liquid crystal alignment layer usually contains a polymer of a part or all of the components contained in the alignment layer composition. For example, when the back-dispersed liquid crystal compound has polymerizability, the back-dispersed liquid crystal compound polymerizes, so that the liquid crystal alignment layer is a polymer of the back-dispersed liquid crystal compound polymerized while maintaining the orientation state before polymerization. It can be a containing layer. As described above, this polymerized inversely dispersed liquid crystal compound is also included in the term "inversely dispersed liquid crystal compound contained in the liquid crystal oriented layer".

In the cured product of the oriented layer composition, the fluidity before curing is lost, so that the oriented state of the inversely dispersed liquid crystal compound is usually fixed as it is before curing. Then, at least a part of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal oriented layer are inclined with respect to the layer plane of the liquid crystal oriented layer (that is, with respect to the in-plane direction).

In the liquid crystal oriented layer, some of the molecules of the inversely dispersed liquid crystal compound may be inclined with respect to the layer plane of the liquid crystal oriented layer (that is, with respect to the in-plane direction), and all of them are layers of the liquid crystal oriented layer. It may be tilted with respect to a plane (ie, in-plane direction). Usually, in the liquid crystal alignment layer, the inclination angle of the molecule of the inversely dispersed liquid crystal compound is larger as it is closer to the specific surface and smaller as it is farther from the specific surface in the thickness direction. Therefore, in the vicinity of the specific plane of the liquid crystal alignment layer, the molecules of the inversely dispersed liquid crystal compound can be perpendicular to the layer plane (that is, to the in-plane direction). Further, in the vicinity of the surface of the liquid crystal alignment layer opposite to the specific surface, the molecules of the inversely dispersed liquid crystal compound may be parallel to the layer plane (that is, with respect to the in-plane direction). However, even when the molecules of the inversely dispersed liquid crystal compound are parallel or perpendicular to the layer plane (that is, with respect to the in-plane direction) in the vicinity of the surface of the liquid crystal alignment layer, the liquid crystal is usually used. The molecules of the inversely dispersed liquid crystal compound are inclined with respect to the layer plane (that is, with respect to the in-plane direction) except for the portion near the surface of the oriented layer.

The fact that at least some molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal oriented layer are inclined with respect to the layer plane of the liquid crystal oriented layer (that is, with respect to the in-plane direction) is polarized light having sufficient resolution. It can be confirmed by observing the cross section of the liquid crystal alignment layer with a microscope. This observation was carried out by inserting a wave plate as an inspection plate between the observation sample and the objective lens of the polarizing microscope, if necessary, in order to make it easier to visually recognize the inclination of the molecules of the inversely dispersed liquid crystal compound. May be good.

Alternatively, the fact that at least a part of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal oriented layer are inclined with respect to the layer plane of the liquid crystal oriented layer (that is, with respect to the in-plane direction) is as follows. Can be confirmed. The retardation R (θ) of the liquid crystal alignment layer at the incident angle θ is measured in the measurement direction perpendicular to the in-plane phase advance axis direction of the liquid crystal alignment layer. Then, the retardation ratio R (θ) / R (0 °) obtained by dividing the retardation R (θ) of the liquid crystal oriented layer at the incident angle θ by the retardation R (0 °) of the liquid crystal oriented layer at the incident angle 0 °. ) Is asked. When a graph is drawn with the retardation ratio R (θ) / R (0 °) obtained in this way on the vertical axis and the incident angle θ on the horizontal axis, the obtained graph should be asymmetric with respect to θ = 0 °. For example, it can be confirmed that at least some molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal oriented layer are inclined with respect to the layer plane of the liquid crystal oriented layer (that is, with respect to the in-plane direction).

Hereinafter, a more specific description will be given with an example. FIG. 3 is a graph in which the retardation ratio R (θ) / R (0 °) of the liquid crystal alignment layer according to a certain example is plotted against the incident angle θ. When the inclination angles of all the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer are 0 ° or 90 °, the retardation ratio R (θ) / R (0 °) is an example shown by a broken line in FIG. As shown above, it is line-symmetric with respect to a straight line of θ = 0 ° (vertical axis passing through θ = 0 ° in FIG. 3). On the other hand, when at least some molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal oriented layer are inclined with respect to the layer plane of the liquid crystal oriented layer (that is, with respect to the in-plane direction), the retardation ratio R (θ) / R (0 °) is usually asymmetric with respect to a straight line of θ = 0 °, as shown by the solid line in FIG. Therefore, when the retardation ratio R (θ) / R (0 °) is asymmetric with respect to θ = 0 °, at least a part of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer is the liquid crystal. It can be determined that the oriented layer is inclined with respect to the layer plane (that is, with respect to the in-plane direction).

Since the liquid crystal oriented layer contains molecules of a inversely dispersed liquid crystal compound inclined with respect to the layer plane of the liquid crystal oriented layer (that is, with respect to the in-plane direction), a substantially maximum inclination angle of 5 ° or more and 85 ° or less is usually obtained. Has. In the liquid crystal alignment layer, the substantially maximum inclination angle is such that the inclination angle of the molecule on the surface opposite to the specific surface of the liquid crystal alignment layer is 0 °, and the inclination angle of the molecule changes at a constant ratio in the thickness direction. It represents the maximum value of the inclination angle of the molecule of the inversely dispersed liquid crystal compound, assuming that it is. This substantially maximum tilt angle is an index indicating the magnitude of the tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer. Generally, the larger the substantially maximum inclination angle of the liquid crystal alignment layer, the larger the inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer as a whole tends to be.

In an optical film produced using a liquid crystal alignment layer, the larger the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer, the more the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal inclined layer. As a result, the substantially maximum tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer can be increased. Since the composite liquid crystal layer having such a large substantially maximum tilt angle has a large tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer as a whole, the optical film provided with the composite liquid crystal layer suppresses reflection. When provided on a polarizing plate as a film, the birefringence in the thickness direction can be appropriately adjusted. Therefore, according to this optical film, reflection can be effectively suppressed in the tilting direction of the display surface, so that the viewing angle characteristic can be improved.

The range of the substantially maximum tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal oriented layer is the substantially maximum of the molecules of the inverse dispersed liquid crystal compound contained in the entire composite liquid crystal layer including the liquid crystal oriented layer and the liquid crystal inclined layer. It is preferable to adjust the tilt angle appropriately so that the excellent viewing angle characteristics can be achieved. Generally, the larger the substantially maximum tilt angle of the liquid crystal alignment layer is, the larger the substantially maximum tilt angle of the composite liquid crystal layer including the liquid crystal alignment layer and the liquid crystal tilt layer can be. The specific range of the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer is preferably 15 ° or more, more preferably 20 ° or more, particularly preferably 30 ° or more, and preferably 60 ° or more. It is below °. Since the substantially maximum tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer is in the above range, it is easy to manufacture an optical film having particularly excellent viewing angle characteristics.

The substantially maximum inclination angle of the molecule of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer can be measured by the measuring method described in Examples described later. According to the measurement method described in Examples described later, even when the liquid crystal alignment layer contains a liquid crystal compound other than the back-dispersion liquid crystal compound, the substantially maximum inclination angle of the molecule of the back-dispersion liquid crystal compound is measured. It is possible.

In the in-plane direction of the liquid crystal alignment layer, the orientation direction of the molecules of the inversely dispersed liquid crystal compound is usually uniform. Therefore, the liquid crystal alignment layer usually has an in-plane slow-phase axis parallel to the orientation direction of the molecules of the inversely dispersed liquid crystal compound when the liquid crystal alignment layer is viewed from the thickness direction. Since the inversely dispersed liquid crystal compound is oriented in a certain orientation direction in the in-plane direction in this way, the liquid crystal alignment layer usually has an in-plane retardation of a predetermined size.

Since the liquid crystal alignment layer is formed by a cured product of the alignment layer composition containing the reverse dispersion liquid crystal compound, it usually has an in-plane retardation of reverse wavelength dispersibility. Here, the reverse wavelength dispersibility in-plane retardation is an in-plane letter in which the in-plane retardation Re (450) at a wavelength of 450 nm and the in-plane retardation Re (550) at a wavelength of 550 nm satisfy the following formula (N3). Refers to the ration. Above all, the in-plane retardation of the liquid crystal alignment layer preferably satisfies the following formula (N4). By combining the liquid crystal alignment layer having the in-plane retardation having the reverse wavelength dispersion in this way with the liquid crystal inclined layer, an optical film having the in-plane retardation having the reverse wavelength dispersion can be obtained.
Re (450) / Re (550) <1.00 (N3)
Re (450) / Re (550) <0.90 (N4)

The specific range of in-plane retardation of the liquid crystal alignment layer can be arbitrarily set according to the use of the optical film produced by using the liquid crystal alignment layer. In particular, in order to obtain a polarizing plate as a reflection-suppressing film for an organic EL display panel by combining an optical film and a linear polarizer, the in-plane retardation of the liquid crystal alignment layer can function as a 1/4 wave plate. It is desirable to set so that an optical film can be obtained.

The liquid crystal alignment layer has a specific surface having the surface free energy in the predetermined range described above. This specific surface can suppress the generation of cissing when a layer of a liquid crystal composition containing a reverse-dispersed liquid crystal compound is formed on the specific surface. Therefore, it is possible to uniformly form a layer of the inclined layer composition on the specific surface.

The liquid crystal alignment layer is usually in a good surface condition. Therefore, the unevenness of the thickness of the liquid crystal alignment layer is usually small, and therefore the unevenness of the in-plane retardation can be reduced.

In the liquid crystal alignment layer, the occurrence of orientation defects is usually suppressed.

The thickness of the liquid crystal alignment layer is preferably 2.5 μm or less, more preferably less than 2.0 μm, still more preferably 1.8 μm or less, particularly preferably 1.5 μm or less, and particularly preferably 1.0 μm or less. In a certain thickness range, the thinner the liquid crystal alignment layer, the larger the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer. Therefore, in a certain predetermined thickness range, the thinner the liquid crystal alignment layer, the more effectively the substantially maximum inclination angle of the liquid crystal inclination layer formed on the specific surface of the liquid crystal alignment layer can be increased. Therefore, since the substantially maximum tilt angle of the composite liquid crystal layer can be effectively increased, the viewing angle characteristic can be greatly improved. Above all, this effect is remarkable when the thickness of the liquid crystal alignment layer is less than 2.0 μm. The lower limit of the thickness T of the liquid crystal alignment layer is not particularly limited, but is preferably 0.1 μm or more, more preferably 0.2 μm or more, and particularly preferably 0.3 μm or more.

(1.5. Manufacturing method of liquid crystal alignment layer)
The method for producing the liquid crystal oriented layer is arbitrary as long as the desired liquid crystal oriented layer can be obtained. In one embodiment, the liquid crystal alignment layer is
(I) With the step of forming a layer of the oriented layer composition;
(Ii) Orientation layer A step of orienting the inversely dispersed liquid crystal compound contained in the layer of the composition;
(Iii) A step of curing the layer of the alignment layer composition to obtain a liquid crystal alignment layer;
It can be manufactured by a manufacturing method including.

In step (i), a layer of the oriented layer composition is usually formed on a suitable support surface. As the supporting surface, any surface capable of supporting the layer of the oriented layer composition can be used. As the support surface, it is preferable to use a flat surface having no recesses or protrusions from the viewpoint of improving the surface condition of the liquid crystal alignment layer. Further, from the viewpoint of increasing the productivity of the liquid crystal alignment layer, it is preferable to use the surface of a long base material as the support surface. Here, "long" means a shape having a length of 5 times or more with respect to the width, preferably having a length of 10 times or more, and specifically being wound in a roll shape. The shape of the film that has a length that allows it to be stored or transported.

As the base material, a resin film or a glass plate is usually used. In particular, when the orientation treatment is performed at a high temperature, it is preferable to select a base material that can withstand the temperature. As the resin, a thermoplastic resin is usually used. Among them, a resin having a positive intrinsic birefringence value is preferable as the resin from the viewpoints of high orientation regulating force, high mechanical strength, and low cost. Further, since it is excellent in transparency, low hygroscopicity, dimensional stability and light weight, it is preferable to use a resin containing an alicyclic structure-containing polymer such as a norbornene resin. A suitable example of the resin contained in the base material is "Zeonoa" manufactured by Zeon Corporation as a norbornene-based resin.

In order to promote the orientation of the inversely dispersed liquid crystal compound in the layer of the alignment layer composition, the surface of the base material as the support surface is preferably treated to impart an orientation regulating force. The orientation regulating force refers to the property of a surface capable of orienting a liquid crystal compound such as a reverse dispersion liquid crystal compound contained in the alignment layer composition. Examples of the treatment for imparting an orientation regulating force to the support surface include a photoalignment treatment, a rubbing treatment, an ion beam orientation treatment, and a stretching treatment.

In the step (i) of forming the layer of the oriented layer composition, the oriented layer composition is usually prepared in a fluid state. Therefore, usually, the orientation layer composition is applied to the support surface to form a layer of the alignment layer composition. Examples of the method for applying the oriented layer composition include curtain coating method, extrusion coating method, roll coating method, spin coating method, dip coating method, bar coating method, spray coating method, slide coating method, and printing coating method. Examples include a gravure coating method, a die coating method, a gap coating method, and a dipping method.

After the step (i) of forming the layer of the alignment layer composition, the step (ii) of orienting the inversely dispersed liquid crystal compound contained in the layer of the alignment layer composition is performed. When the orientation is performed, the layer of the alignment layer composition is usually held in a predetermined temperature condition for a predetermined time. As a result, the liquid crystal compound such as the inverse dispersion liquid crystal compound is oriented in the layer of the alignment layer composition.

Normally, in the in-plane direction, the inversely dispersed liquid crystal compound is oriented in a direction corresponding to the orientation restricting force of the support surface. Further, if the oriented layer composition contains a tilting action component, at least a part of the inversely dispersed liquid crystal compound is greatly tilted with respect to the layer plane (that is, with respect to the in-plane direction) in the thickness direction. Since it is oriented, it is possible to increase the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the layer of the oriented layer composition.

Further, the step (ii) is preferably performed by adjusting the operation or conditions so that a liquid crystal alignment layer having a large substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound can be obtained.

For example, step (ii) is preferably performed so that the temperature conditions of the layers of the oriented layer composition satisfy predetermined requirements. Specifically, it is preferable that the temperature condition of the layer of the oriented layer composition in step (ii) is the same as the temperature condition at which the residual viscosity of the test composition is usually 800 cP or less. The test composition is a composition having a composition obtained by removing the polymerization initiator from the alignment layer composition. The residual viscosity of the test composition is the viscosity of the residual component of the test composition under the same temperature conditions as the layer of the oriented layer composition in step (ii). The residual component of the test composition is a component contained in the test composition that remains without vaporization under the same temperature conditions as the layer of the orientation layer composition of step (ii). By performing step (ii) so as to satisfy such requirements, it is possible to increase the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer.

This will be described in more detail. When the step (ii) of orienting the inversely dispersed liquid crystal compound is performed so as to satisfy the above requirements, the step (ii) is set to the same temperature condition as the temperature condition in which the residual viscosity of the test composition falls within a predetermined range. , Alignment layer The layer of the composition is adjusted. The specific range of the residual viscosity is usually 800 cP (centipores) or less, preferably 600 cP or less, more preferably 400 cP or less, still more preferably 200 cP or less. By orienting the liquid crystal compounds in the layer of the alignment layer composition under the same temperature conditions as those in which the residual viscosity of the test composition is lowered in this way, the molecules of the inversely dispersed liquid crystal compounds contained in the liquid crystal alignment layer. The actual maximum tilt angle of is increased. The lower limit of the residual viscosity is preferably 5 cP or more, more preferably 10 cP or more, from the viewpoint of obtaining a liquid crystal alignment layer having a desired thickness.

The residual viscosity of the test composition under the same temperature conditions as the layer of the oriented layer composition in step (ii) can be measured by the following method.
A test composition obtained by removing the polymerization initiator from the alignment layer composition is prepared. The test composition is concentrated under reduced pressure on a rotary evaporator to remove the solvent to obtain residual components. The viscosity of this residual component is measured in advance while changing the measurement temperature, and information on the measurement temperature and the viscosity at the measurement temperature is obtained. This information is hereinafter appropriately referred to as "temperature-viscosity information". From this "temperature-viscosity information", the viscosity at the temperature of the layer of the oriented layer composition in step (ii) is read as the residual viscosity.

Examples of the method for keeping the residual viscosity of the test composition within the above-mentioned range under the same temperature conditions as the layer of the oriented layer composition in the step (ii) include the following methods (A) and (B).
(A) The temperature of the layer of the alignment layer composition in the step (ii) of orienting the inversely dispersed liquid crystal compound is appropriately adjusted. In this method, usually, the temperature of the layer of the oriented layer composition is sufficiently high, so that the residual viscosity of the test composition under the same temperature condition as this temperature is lowered so as to be within the above range. adjust.
(B) The composition of the oriented layer composition is appropriately adjusted. In this method, the residual viscosity of the test composition containing the additive is usually lowered by combining the inverse dispersion liquid crystal compound with an appropriate type and amount of the additive as a component contained in the alignment layer composition. Then, adjust so that it is within the above-mentioned range.

For the adjustment of the temperature condition of the layer of the oriented layer composition in the step (ii), the description of International Publication No. 2018/173773 and Japanese Patent Application No. 2017-060159 may be referred to.

Further, for example, when an oriented layer composition containing a liquid crystal compound having magnetic field responsiveness is used, it is preferable to perform step (ii) in a state where a magnetic field is applied to the layer of the oriented layer composition. As a result, it is possible to increase the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer.

The direction of the magnetic field applied to the layer of the oriented layer composition is usually not perpendicular to the thickness direction of the layer of the oriented layer composition, and is preferably parallel to the thickness direction of the layer of the oriented layer composition. The direction. By applying a magnetic field in such a direction, the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer can be effectively increased.

The magnetic flux density of the magnetic field applied to the layer of the oriented layer composition is preferably 0.2 tesla or more, more preferably 0.5 tesla or more, and particularly preferably 0.8 tesla or more. By applying a magnetic field of such a magnitude, the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer can be effectively increased. There is no limit to the upper limit of the magnetic flux density of the magnetic field, which may be, for example, 20.0 tesla or less. Regarding the application of a magnetic field, the description in JP-A-2018-163218 and Japanese Patent Application Laid-Open No. 2017-059327 may be referred to.

The specific temperature at the time of the orientation treatment is appropriately set in the range of the liquid crystallinization temperature of the inversely dispersed liquid crystal compound or higher, and above all, the temperature is preferably lower than the glass transition temperature of the resin contained in the substrate. As a result, it is possible to suppress the occurrence of distortion of the base material due to the orientation treatment.

The step (ii) of orienting the inversely dispersed liquid crystal compound is usually performed in an oven. At this time, the set temperature of the oven and the temperature of the layer of the oriented layer composition placed in the oven may be different. In this case, it is preferable to measure and record the temperature of the layer of the alignment layer composition placed in the oven at the set temperature in advance at a large number of oven set temperatures. The recorded information on the set temperature of the oven and the temperature of the layer of the oriented layer composition placed in the oven at the set temperature is hereinafter appropriately referred to as "set temperature-layer temperature information". By using this "set temperature-layer temperature information", the temperature of the layer of the oriented layer composition placed in the oven can be easily known from the oven set temperature.

In the step (ii) of orienting the reverse dispersion liquid crystal compound, the time for holding the temperature of the layer of the alignment layer composition at the above temperature can be arbitrarily set within a range in which a desired liquid crystal alignment layer can be obtained, for example, 30 seconds. It can be up to 5 minutes.

After the step (ii) of aligning the inversely dispersed liquid crystal compound, the step (iii) of curing the layer of the alignment layer composition to obtain a liquid crystal oriented layer is performed. In this step (iii), a part or all of a liquid crystal compound such as a reverse dispersion liquid crystal compound is usually polymerized to cure the layer of the oriented layer composition. At the time of polymerization, the liquid crystal compound is usually polymerized while maintaining the orientation of its molecule. Therefore, the orientation state of the liquid crystal compound contained in the alignment layer composition before the polymerization is fixed by the above-mentioned polymerization.

As the polymerization method, a method suitable for the properties of the components contained in the oriented layer composition can be selected. Examples of the polymerization method include a method of irradiating with active energy rays and a thermal polymerization method. Above all, the method of irradiating with active energy rays is preferable because heating is not required and the polymerization reaction can proceed at room temperature. Here, the activated energy rays to be irradiated may include light such as visible light, ultraviolet rays, and infrared rays, and arbitrary energy rays such as electron beams.

Of these, a method of irradiating light such as ultraviolet rays is preferable because the operation is simple. The temperature at the time of ultraviolet irradiation is preferably not more than the glass transition temperature of the base material, preferably 150 ° C. or less, more preferably 100 ° C. or less, and particularly preferably 80 ° C. or less. The lower limit of the temperature at the time of ultraviolet irradiation can be 15 ° C. or higher. The irradiation intensity of ultraviolet rays is preferably 0.1 mW / cm ² or more, more preferably 0.5 mW / cm ² or more, preferably 10000 mW / cm ² or less, more preferably 5000 mW / cm ² or less, more preferably 1000mW It is / cm ² or less, particularly preferably 600 mW / cm ² or less. The dose of ultraviolet rays is preferably 0.1 mJ / cm ² or more, more preferably 0.5 mJ / cm ² or more, preferably 10000 mJ / cm ² or less, more preferably 5000 mJ / cm ² or less.

The liquid crystal alignment layer can be produced by the production method described above. In this manufacturing method, a liquid crystal alignment layer formed on a support surface of a base material is usually obtained.

The method for producing the liquid crystal alignment layer described above may be combined with the steps (i) to (iii) described above, and may further include an arbitrary step.
For example, the method for producing the liquid crystal alignment layer may include a step of peeling the liquid crystal alignment layer from the support surface.

According to the manufacturing method as described above, a long liquid crystal alignment layer can be obtained by using a long base material. Such a long liquid crystal alignment layer can be continuously manufactured and is excellent in productivity. Generally, a film containing a long liquid crystal alignment layer is wound and stored and transported in a roll state.

[2. Optical film]
(2.1. Outline of optical film)
As shown in FIG. 2, the optical film 200 according to the embodiment of the present invention includes a liquid crystal alignment layer 100 and a liquid crystal inclined layer 210 in direct contact with a specific surface 100U of the liquid crystal alignment layer 100. Therefore, the optical film 200 includes a composite liquid crystal layer 220 including a liquid crystal alignment layer 100 and a liquid crystal inclined layer 210. When another layer is "directly" in contact with the surface of one layer, it means that there is no other layer between these two layers.

The liquid crystal gradient layer 210 is formed of a cured product of the gradient layer composition containing a reverse dispersion liquid crystal compound. Since it is formed of a cured product of the gradient layer composition, the liquid crystal gradient layer 210 contains molecules of a reversely dispersed liquid crystal compound. The molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal gradient layer 210 are usually fixed in the oriented state. Similar to the liquid crystal alignment layer 100, the polymerized reverse-dispersed liquid crystal compound is included in the term “reverse-dispersed liquid crystal compound contained in the liquid crystal inclined layer”.

At least some molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal inclined layer 210 are inclined with respect to the layer plane of the liquid crystal inclined layer 210 (that is, with respect to the in-plane direction). Here, the specific surface 100U of the liquid crystal alignment layer 100 has an orientation restricting force for orienting the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal inclined layer 210 formed on the specific surface 100U. In the in-plane direction, this orientation regulating force orients the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal inclined layer 210 in the same direction as the orientation direction of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer 100. Try to make it. Further, the orientation regulating force attempts to orient the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal gradient layer 210 in the thickness direction so that the inclination angle of the molecules becomes large. Therefore, the liquid crystal alignment layer 100 can function as an alignment film that increases the inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal inclination layer 210. Therefore, the tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal tilting layer 210 can be increased by the action of the liquid crystal alignment layer 100. Therefore, the inclination angle of the molecules of the inversely dispersed liquid crystal compound as a whole of the composite liquid crystal layer 220 including the liquid crystal alignment layer 100 and the liquid crystal inclined layer 210 can be increased. Since the inclination angle of the molecules of the inversely dispersed liquid crystal compound as a whole of the composite liquid crystal layer 220 can be increased in this way, when the optical film 200 including the composite liquid crystal layer 220 is provided on the reflection suppression film, the thickness direction The birefringence in the above can be adjusted appropriately. Therefore, according to this optical film 200, reflection can be effectively suppressed in the tilting direction of the display surface, so that the viewing angle characteristics can be improved.

Further, since the liquid crystal gradient layer 210 contains a reverse dispersion liquid crystal compound, the liquid crystal gradient layer 210 has an in-plane retardation of reverse wavelength dispersibility. Therefore, since both the liquid crystal alignment layer 100 and the liquid crystal inclined layer 210 have an in-plane retardation having a reverse wavelength dispersion, the optical film 200 including the layers 100 and 210 has an in-plane retardation having a reverse wavelength dispersion. Can have.

Further, when the layer of the inclined layer composition is formed on the specific surface 100U of the liquid crystal alignment layer 100, the repelling of the inclined layer composition on the specific surface 100U can be suppressed. Therefore, it is possible to prevent the formation of a portion without the liquid crystal inclined layer 210 on the specific surface 100U or the formation of a portion thicker than intended by the liquid crystal inclined layer 210, so that the liquid crystal inclined layer uniform in the in-plane direction. You can get 210.

Therefore, the optical film 200 including the liquid crystal alignment layer 100 and the liquid crystal inclined layer 210 in combination has an in-plane retardation having anti-wavelength dispersibility, can be produced while suppressing the repelling of the inclined layer composition, and has a visual field. Excellent angular characteristics.

Further, in the optical film 200, orientation defects of the liquid crystal inclined layer 210 and the composite liquid crystal layer 220 can usually be reduced.

Further, in the optical film 200, the surface condition of the liquid crystal inclined layer 210 and the composite liquid crystal layer 220 can usually be improved.

(2.2. Liquid crystal inclined layer)
The liquid crystal gradient layer is a layer formed of a cured product of the gradient layer composition containing a reverse dispersion liquid crystal compound. As the reverse dispersion liquid crystal compound contained in the inclined layer composition, any reverse dispersion liquid crystal compound can be selected and used from the range described as the reverse dispersion liquid crystal compound contained in the oriented layer composition. Thereby, the same advantages obtained in the oriented layer composition and the liquid crystal oriented layer can be obtained in the inclined layer composition and the liquid crystal inclined layer. The inversely dispersed liquid crystal compound contained in the inclined layer composition may be the same as or different from the inverse dispersed liquid crystal compound contained in the oriented layer composition. Further, as the inverse dispersion liquid crystal compound contained in the inclined layer composition, one kind may be used alone, or two or more kinds may be used in combination at an arbitrary ratio.

Further, the inclined layer composition may contain any component in combination with the inversely dispersed liquid crystal compound, if necessary. As the arbitrary component, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio. As the optional component, for example, a component other than the inversely dispersed liquid crystal compound that can be contained in the oriented layer composition can be used within the range of the amount of the component in the oriented layer composition. Thereby, the same advantages obtained in the oriented layer composition and the liquid crystal oriented layer can be obtained in the inclined layer composition and the liquid crystal inclined layer.

The inclined layer composition may be different from or the same as the oriented layer composition.

Curing of the inclined layer composition is usually achieved by polymerization of the polymerizable compound contained in the inclined layer composition, similarly to curing of the oriented layer composition. Therefore, the liquid crystal inclined layer usually contains a polymer of a part or all of the components contained in the inclined layer composition. For example, when the back-dispersed liquid crystal compound has polymerizability, the back-dispersed liquid crystal compound polymerizes, so that the liquid crystal gradient layer is a polymer of the back-dispersed liquid crystal compound polymerized while maintaining the orientation state before polymerization. It can be a containing layer.

In the cured product of the inclined layer composition, the fluidity before curing is lost, so that the orientation state of the inversely dispersed liquid crystal compound is usually fixed in the orientation state before curing. The molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal inclined layer are greatly inclined with respect to the layer plane of the liquid crystal inclined layer (that is, with respect to the in-plane direction) due to the action of the liquid crystal alignment layer. Therefore, the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal inclined layer can be increased. In the liquid crystal inclined layer, it is assumed that the substantially maximum inclination angle of the molecule is 0 ° on the surface on the liquid crystal alignment layer side, and the inclination angle of the molecule changes at a constant ratio in the thickness direction. Represents the maximum value of the tilt angle of the molecule of the inversely dispersed liquid crystal compound in the case. This substantially maximum tilt angle is an index indicating the magnitude of the tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal tilt layer. Normally, the larger the substantially maximum tilt angle of the liquid crystal tilting layer, the larger the tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal tilting layer as a whole tends to be. Due to the action of the liquid crystal alignment layer, the actual maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer is usually larger than the actual maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer. , Can be made larger.

The substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal inclined layer is preferably 45 ° or more, more preferably 50 ° or more, particularly preferably 57 ° or more, and preferably 85 ° or less. When the substantially maximum tilt angle of the molecule of the inversely dispersed liquid crystal compound contained in the liquid crystal tilt layer is within the above range, particularly excellent viewing angle characteristics can be obtained.

The substantially maximum inclination angle of the molecule of the inversely dispersed liquid crystal compound contained in the liquid crystal inclined layer can be measured by the following method.
The substantially maximum inclination angle of the molecule of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer is measured. In addition, the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the entire composite liquid crystal layer including the liquid crystal alignment layer and the liquid crystal inclined layer is measured. Then, the substantially maximum tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal tilt layer can be calculated by using these measured substantially maximum tilt angles and the thicknesses of the liquid crystal alignment layer and the liquid crystal tilt layer.

Further, the difference between the substantially maximum tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer and the substantially maximum tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal inclined layer is preferably 5 ° or more. , More preferably 8 ° or more, particularly preferably 10 ° or more, preferably 70 ° or less, more preferably 65 ° or less, and particularly preferably 55 ° or less. When the difference in the substantially maximum tilt angle is within the above range, particularly excellent viewing angle characteristics can be obtained.

Usually, the orientation direction of the molecules of the inversely dispersed liquid crystal compound in the in-plane direction of the liquid crystal inclined layer is the same as the orientation direction of the molecules of the inverse dispersed liquid crystal compound in the in-plane direction of the liquid crystal alignment layer.

Further, in the liquid crystal inclined layer, the occurrence of orientation defects can usually be suppressed.

Further, the liquid crystal inclined layer is usually in a good surface condition.

The thickness of the liquid crystal inclined layer is not particularly limited, and is preferably 0.3 μm or more, more preferably 0.5 μm or more, and preferably 10.0 μm or less, more preferably 7.5 μm or less, still more preferably. It is 5.0 μm or less, particularly preferably 3.0 μm or less.

(2.3. Composite liquid crystal layer)
The optical film is formed by curing a liquid crystal oriented layer formed of a cured product of an oriented layer composition as a liquid crystal composition containing a reverse dispersion liquid crystal compound and a gradient layer composition as a liquid crystal composition containing a reverse dispersion liquid crystal compound. It includes a liquid crystal inclined layer formed of an object. Therefore, the optical film includes a composite liquid crystal layer including a liquid crystal alignment layer and a liquid crystal inclined layer as a liquid crystal cured layer having a multi-layer structure formed of a cured product of a liquid crystal composition containing a reverse dispersion liquid crystal compound.

As can be seen from the inclusion of the liquid crystal alignment layer and the liquid crystal inclined layer, at least a part of the molecules of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer is relative to the layer plane of the composite liquid crystal layer (that is, in the in-plane direction). On the other hand, it is inclined. The fact that at least some of the molecules of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer are inclined with respect to the layer plane (that is, with respect to the in-plane direction) is the same as the method described in the section of the liquid crystal oriented layer. It can be confirmed by the method. Then, in the composite liquid crystal layer including the liquid crystal alignment layer and the liquid crystal inclined layer, it is possible to increase the inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer as a whole. Therefore, the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer can be increased.

In the composite liquid crystal layer, the substantial maximum inclination angle is when it is assumed that the inclination angle of the molecule on the surface on the liquid crystal alignment layer side is 0 ° and the inclination angle of the molecule changes at a constant ratio in the thickness direction. Represents the maximum value of the inclination angle of the molecule of the inversely dispersed liquid crystal compound. This substantially maximum tilt angle is an index indicating the magnitude of the tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer. Generally, the larger the substantially maximum tilt angle of the composite liquid crystal layer, the larger the tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer as a whole tends to be. Therefore, the birefringence of the composite liquid crystal layer in the thickness direction can be increased by increasing the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer. Then, since the birefringence of the composite liquid crystal layer can be increased in the thickness direction, the birefringence in the thickness direction of the optical film can be appropriately adjusted. Therefore, when the optical film is provided on the polarizing plate as the reflection suppression film, it is possible to obtain an excellent viewing angle characteristic that reflection can be effectively suppressed in the tilting direction of the display surface.

The substantially maximum tilt angle of the molecule of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer is usually larger than the substantially maximum tilt angle of the molecule of the inverse dispersed liquid crystal compound contained in the liquid crystal alignment layer. From the viewpoint of achieving excellent viewing angle characteristics, the substantially maximum tilt angle of the molecules of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer is preferably 40 ° or more, more preferably 46 ° or more, and particularly preferably 56 ° or more. It is preferably 85 ° or less, more preferably 83 ° or less, still more preferably 80 ° or less. When the substantially maximum inclination angle of the molecule of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer is in the above range, the birefringence in the thickness direction of the optical film can be appropriately adjusted. Therefore, by combining this optical film with a linear polarizer, it is possible to realize a polarizing plate capable of achieving high viewing angle characteristics when provided on an organic EL display panel.

The substantially maximum inclination angle of the molecule of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer can be measured by the measuring method described in Examples described later. According to the measurement method described in Examples described later, even when the composite liquid crystal layer contains a liquid crystal compound other than the back-dispersion liquid crystal compound, the substantially maximum inclination angle of the molecule of the back-dispersion liquid crystal compound is measured. It is possible.

Since the composite liquid crystal layer includes a liquid crystal alignment layer containing a reverse dispersion liquid crystal compound and a liquid crystal gradient layer, it can have an in-plane retardation having reverse wavelength dispersibility. Therefore, the in-plane retardation of the composite liquid crystal layer usually satisfies the above formula (N3), and preferably satisfies the above formula (N4).

As described above, the cissing of the inclined layer composition is suppressed on the specific surface of the liquid crystal alignment layer. As a result, it is possible to prevent the formation of a portion without the liquid crystal inclined layer on the specific surface. Therefore, the composite liquid crystal layer can have a multi-layer structure including a combination of a liquid crystal alignment layer and a liquid crystal inclined layer in a wide range continuous in the in-plane direction.

In the in-plane direction, the molecules of the inversely dispersed liquid crystal compound contained in the composite liquid crystal layer are generally oriented in the same in-plane direction as the orientation direction of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer. Therefore, the in-plane slow-phase axis of the composite liquid crystal layer is usually parallel to the in-plane slow-phase axis of the liquid crystal alignment layer.

In the composite liquid crystal layer, the occurrence of orientation defects is usually suppressed.

The composite liquid crystal layer is usually in a good surface condition. Therefore, the unevenness of the thickness of the composite liquid crystal layer is usually small, and therefore the unevenness of the in-plane retardation is small.

The thickness of the composite liquid crystal layer is preferably 0.5 μm or more, more preferably 1.0 μm or more, preferably 12.5 μm or less, more preferably less than 9.5 μm, still more preferably 6.8 μm or less, and particularly preferably. It is 6.5 μm or less, particularly preferably 4.0 μm or less. When the thickness of the composite liquid crystal layer is within the above range, the characteristics such as in-plane retardation can be easily adjusted to a desired range. Further, since the composite liquid crystal layer having such a thickness is thinner than the conventional retardation film used for the reflection suppression film of the organic EL display panel, it can contribute to the thinning of the organic EL display panel.

By the way, the composite liquid crystal layer may be a liquid crystal cured layer having a two-layer structure including only one liquid crystal alignment layer and one liquid crystal inclined layer, but is a liquid crystal cured layer including three or more layers. May be good. For example, as the liquid crystal inclined layer, a layer having a specific surface having the surface free energy in the predetermined range may be obtained. This liquid crystal inclined layer can function as a liquid crystal alignment layer. Therefore, by forming another liquid crystal inclined layer on the liquid crystal inclined layer, a composite liquid crystal layer including three or more layers can be obtained.

In the composite liquid crystal layer, the liquid crystal alignment layer and the liquid crystal inclined layer can usually be distinguished by the following method.
The composite liquid crystal layer is embedded with an epoxy resin to obtain a sample piece. This sample piece is sliced parallel to the thickness direction of the composite liquid crystal layer using a microtome to obtain an observation sample. At this time, slicing is performed so that the in-plane slow-phase axial direction and the cross section of the composite liquid crystal layer are parallel. Then, the cross section revealed by the slice is observed using a polarizing microscope. This observation is performed by inserting a wave plate as an inspection plate between the observation sample and the objective lens of the polarizing microscope so that an image having a color corresponding to the retardation of the observation sample can be seen. At this time, the portions having different colors can be distinguished as the boundary between the liquid crystal alignment layer and the liquid crystal inclined layer.

(2.4. Arbitrary layer)
The optical film may be a film containing only the liquid crystal alignment layer and the liquid crystal tilting layer, or may be a film containing an arbitrary layer in combination with the liquid crystal alignment layer and the liquid crystal tilting layer. As an arbitrary layer, a base material used for producing a liquid crystal alignment layer; a retardation film; an adhesive layer for adhering to other members; a matte layer for improving the slipperiness of the film; an impact-resistant polymethacrylate resin layer, etc. Hard coat layer; antireflection layer; antifouling layer; etc.

(2.5. Characteristics of optical film)
Since the optical film includes a composite liquid crystal layer including a liquid crystal alignment layer and a liquid crystal inclined layer, birefringence in the thickness direction of the optical film can be appropriately adjusted. Therefore, when the optical film is provided on the polarizing plate as the reflection suppression film, it is possible to obtain an excellent viewing angle characteristic that reflection can be effectively suppressed in the tilting direction of the display surface.

From the viewpoint of realizing excellent viewing angle characteristics, the average retardation ratio R (± 50 °) / R (0 °) of the optical film is preferably 0.90 or more, more preferably 0.92 or more, and particularly preferably 0.92 or more. It is 0.93 or more, preferably 1.15 or less, more preferably 1.12 or less, and particularly preferably 1.10 or less. Here, R (± 50 °) is the retardation of the optical film at incident angles θ of −50 ° and + 50 °, measured in the measurement direction perpendicular to the in-plane phase advance axis direction of the optical film. Represents the average value of R (-50 °) and R (+ 50 °). Further, R (0 °) represents the retardation of the optical film at an incident angle of 0 °.

Generally, external light incident on the display surface of an image display device at an incident angle of “+ φ” is reflected at an emitted angle of “−φ”. Therefore, when the reflection suppression film provided on the display surface includes an optical film, the external light is optical in the inclination direction of the display surface in the path including the outward path at the incident angle “+ φ” and the return path at the exit angle “−φ”. Pass through the film. From the viewpoint of effectively suppressing the reflection of light passing through this path, the retardation ratio R (± 50 °) / R (0 °) of the optical film is preferably close to 1.00. When the retardation ratio R (± 50 °) / R (0 °) of the optical film is in the above range close to 1.00, the polarizing plate including the optical film has an effect of reflecting external light in the tilt direction. Can be suppressed. Specifically, it is possible to appropriately convert the polarization state of the outside light while it passes through the optical film twice, when it is incident and when it is reflected, and to realize effective blocking by the linear polarizer of the polarizing plate. It becomes. Therefore, when such an optical film is combined with a linear polarizing element to obtain a polarizing plate, the reflection suppression ability of the polarizing plate can be exhibited in a wide angle of view range, so that particularly excellent viewing angle characteristics can be obtained. it can.

Since the optical film includes a composite liquid crystal layer including a liquid crystal alignment layer and a liquid crystal inclined layer, it can have an in-plane retardation having anti-wavelength dispersibility. Therefore, the in-plane retardation of the optical film usually satisfies the above formula (N3), and preferably satisfies the above formula (N4). As described above, an optical film having an in-plane retardation having a reverse wavelength dispersibility can exhibit its optical function in a wide wavelength range. Therefore, when this optical film is used as a polarizing plate as a reflection suppressing film, it is possible to suppress reflection in a wide wavelength range.

The specific range of in-plane retardation of the optical film can be arbitrarily set according to the application of the optical film. In particular, in order to obtain a polarizing plate as a reflection-suppressing film for an organic EL display panel in combination with a linear polarizer, it is desirable that the optical film has an in-plane retardation capable of functioning as a 1/4 wave plate. Here, the in-plane retardation capable of functioning as a quarter wave plate is specifically, at a measurement wavelength of 590 nm, preferably 100 nm or more, more preferably 110 nm or more, particularly preferably 120 nm or more, and preferably 180 nm. Below, it is more preferably 170 nm or less, and particularly preferably 160 nm or less.

As described above, the composite liquid crystal layer included in the optical film can have a multi-layer structure including a combination of a liquid crystal alignment layer and a liquid crystal inclined layer in a wide range continuous in the in-plane direction. Therefore, since this optical film is usually easy to manufacture in a large area, efficient production is possible.

In the composite liquid crystal layer included in the optical film, the occurrence of orientation defects is usually suppressed. Therefore, if this optical film is used, it is possible to suppress the occurrence of optical defect points whose in-plane retardation is different from the surroundings. Therefore, in the reflection suppression film produced by using this optical film, it is possible to suppress the occurrence of a portion where the reflection cannot be suppressed as intended.

The composite liquid crystal layer included in the optical film is usually in a good surface condition. Therefore, since the unevenness of the thickness of the composite liquid crystal layer is small, the optical film can reduce the unevenness of the in-plane retardation.

The optical film preferably has excellent transparency. Specifically, the total light transmittance of the optical film is preferably 75% or more, more preferably 80% or more, and particularly preferably 84% or more. The haze of the optical film is preferably 5% or less, more preferably 3% or less, and particularly preferably 1% or less. The total light transmittance can be measured in the wavelength range of 400 nm to 700 nm using an ultraviolet / visible spectrometer. Haze can also be measured using a haze meter.

The thickness of the optical film is preferably 0.5 μm or more, more preferably 1.0 μm or more, preferably 300 μm or less, and more preferably 200 μm or less.

(2.6. Manufacturing method of optical film)
The method for producing the optical film is arbitrary as long as the desired optical film can be obtained. In one embodiment, the optical film is
(Iv) A step of forming a layer of the inclined layer composition directly on a specific surface of the liquid crystal alignment layer;
(V) A step of orienting the inversely dispersed liquid crystal compound contained in the layer of the inclined layer composition;
(Vi) A step of curing the layer of the inclined layer composition to obtain a liquid crystal inclined layer, and
It can be manufactured by a manufacturing method including.

In step (iv), a layer of the inclined layer composition is formed directly on a specific surface of the liquid crystal alignment layer. Here, the aspect of forming another layer on the surface of one layer is "directly" means that there is no other layer between these two layers.

Before forming the layer of the inclined layer composition on the specific surface of the liquid crystal alignment layer, the specific surface may be subjected to a treatment for imparting an orientation regulating force such as a rubbing treatment. However, the specific surface of the liquid crystal alignment layer has an orientation regulating force that appropriately orients the reverse-dispersed liquid crystal compound contained in the layer of the inclined layer composition formed on the specific surface without any special treatment. Have. Therefore, from the viewpoint of reducing the number of steps and efficiently advancing the production of the optical film, in step (iv), the inclined layer is directly applied to the specific surface of the liquid crystal alignment layer without rubbing treatment on the specific surface of the liquid crystal alignment layer. It preferably comprises forming a layer of the composition.

In the step (iv) of forming the layer of the inclined layer composition, the inclined layer composition is usually prepared in a fluid state. Therefore, usually, the inclined layer composition is applied to a specific surface of the liquid crystal alignment layer to form a layer of the inclined layer composition. Examples of the method of applying the inclined layer composition include the same examples as the method described as the method of applying the oriented layer composition. When the surface free energy of the specific surface of the liquid crystal alignment layer is in the above range, the repelling of the inclined layer composition on the specific surface is suppressed. Therefore, usually, the coatability of the inclined layer composition on a specific surface of the liquid crystal oriented layer is good, so that a layer of the inclined layer composition having a good surface condition is formed. Further, since the liquid crystal oriented layer is formed of a cured product containing the reverse dispersion liquid crystal compound, the liquid crystal alignment layer usually has a high affinity for the inclined layer composition containing the reverse dispersion liquid crystal compound. Therefore, usually, the inclined layer composition is well-adapted to the specific surface of the liquid crystal alignment layer. Therefore, the occurrence of unevenness in the layer of the inclined layer composition can be suppressed.

After the step (iv) of forming the layer of the inclined layer composition, the step (v) of orienting the inversely dispersed liquid crystal compound contained in the layer of the inclined layer composition is performed. As a result, the liquid crystal compound such as the inverse dispersion liquid crystal compound is oriented in the layer of the inclined layer composition.

Usually, in the in-plane direction, the inversely dispersed liquid crystal compound contained in the layer of the inclined layer composition is oriented in the orientation direction of the inversely dispersed liquid crystal compound contained in the liquid crystal oriented layer due to the orientation restricting force of the specific surface of the liquid crystal oriented layer. Oriented in the same direction as. On the other hand, in the thickness direction, the inversely dispersed liquid crystal compound contained in the layer of the inclined layer composition is oriented so that at least a part thereof is inclined with respect to the layer plane (that is, with respect to the in-plane direction). At this time, the molecules of the inversely dispersed liquid crystal compound contained in the layer of the inclined layer composition are greatly inclined with respect to the layer plane (that is, with respect to the in-plane direction) by the action of the liquid crystal alignment layer. Therefore, the substantially maximum inclination angle of the molecule of the inversely dispersed liquid crystal compound contained in the layer of the inclined layer composition can be increased.

Further, as described above, the liquid crystal oriented layer has a high affinity for the inclined layer composition. Therefore, the inclined layer composition is familiar with the liquid crystal alignment layer, and the orientation of the molecules is not easily disturbed. Therefore, in the inclined layer composition, the orientation state can be made uniform in the in-plane direction. Therefore, in step (v), the occurrence of orientation defects is usually suppressed.

The specific operation in the step (v) of orienting the reverse dispersion liquid crystal compound contained in the layer of the inclined layer composition is the step (ii) of orienting the reverse dispersion liquid crystal compound contained in the layer of the alignment layer composition. Can be the same. Thereby, the same advantages obtained in the oriented layer composition and the liquid crystal oriented layer can be obtained in the inclined layer composition and the liquid crystal inclined layer. In particular, in step (v), as in step (ii), the temperature condition of the layer of the inclined layer composition in step (v) is such that the residual viscosity of the test composition corresponding to the inclined layer composition is usually 800 cP or less. It is preferable to carry out the process so as to be the same as the temperature condition.

After the step (v) of orienting the inversely dispersed liquid crystal compound, the step (vi) of curing the layer of the inclined layer composition to obtain the liquid crystal inclined layer is performed. Thereby, an optical film including a composite liquid crystal layer including a liquid crystal alignment layer and a liquid crystal inclined layer can be obtained. The specific operation in the step (vi) of curing the layer of the inclined layer composition can be the same as the step (iii) of curing the layer of the oriented layer composition. Thereby, the same advantages obtained in the oriented layer composition and the liquid crystal oriented layer can be obtained in the inclined layer composition and the liquid crystal inclined layer.

The method for producing an optical film may further include an arbitrary step in combination with the above-mentioned steps.
The method for producing an optical film may include, for example, a step of forming another liquid crystal inclined layer on the liquid crystal inclined layer.
Further, the method for producing an optical film may include, for example, a step of forming an arbitrary layer on the liquid crystal inclined layer.
Further, a step of forming an arbitrary layer on the side of the liquid crystal alignment layer opposite to the liquid crystal inclined layer may be included.

When a layer formed on the support surface of the base material is used as the liquid crystal alignment layer, a composite liquid crystal layer is formed on the base material according to the above-mentioned manufacturing method. A film containing this base material and a composite liquid crystal layer may be used as an optical film. Further, the method for producing an optical film may include a step of peeling off the base material. In this case, the composite liquid crystal layer itself can be used as an optical film.

Further, the method for producing an optical film may include, for example, a step of transferring a composite liquid crystal layer formed on a base material to an arbitrary film layer. Therefore, for example, in the method of manufacturing an optical film, after the composite liquid crystal layer formed on the base material and an arbitrary film layer are bonded together, the base material is peeled off as necessary to form the composite liquid crystal layer and an arbitrary film layer. The step of obtaining an optical film containing the film layer of the above may be included. At this time, an appropriate adhesive or adhesive may be used for bonding.

According to the manufacturing method as described above, a long optical film can be obtained by using a long liquid crystal alignment layer. Such a long optical film can be continuously manufactured and is excellent in productivity. Further, since the film can be bonded to another film by roll-to-roll, the productivity is excellent in this respect as well. Usually, a long optical film is wound and stored and transported in a roll state.

[3.1 / 4 wave plate]
The quarter wave plate according to the embodiment of the present invention includes the above-mentioned liquid crystal alignment layer or optical film. Further, the quarter wave plate may further include an arbitrary layer in combination with the liquid crystal alignment layer or the optical film.

This 1/4 wave plate has an in-plane retardation in the above range as an in-plane retardation that can function as a 1/4 wave plate. By combining the 1/4 wave plate with a linear polarizing element, a circular polarizing plate that can be used as a reflection suppression film can be obtained. The circular polarizing plate thus obtained can be used as a reflection-suppressing film having an in-plane retardation having anti-wavelength dispersibility and having excellent viewing angle characteristics.

[4. Polarizer]
The polarizing plate according to the embodiment of the present invention includes the above-mentioned liquid crystal alignment layer or optical film. Usually, the polarizing plate includes a linear polarizer in combination with a liquid crystal alignment layer or an optical film. It is preferable that this polarizing plate can function as a circular polarizing plate or an elliptical polarizing plate. By providing such a polarizing plate on the organic EL display panel, it is possible to suppress reflection of external light in the front direction of the display surface of the organic EL display panel. At this time, since the liquid crystal alignment layer and the optical film have an in-plane retardation having anti-wavelength dispersibility, it is possible to suppress reflection of external light in a wide wavelength range. Further, as can be seen from the fact that the substantially maximum inclination angle of the molecules of the inversely dispersed liquid crystal compound is large in the liquid crystal alignment layer and the optical film described above, the inclination angle of the molecules of the inversely dispersed liquid crystal compound is large as a whole. Birefringence can be appropriately adjusted not only in the inward direction but also in the thickness direction. Therefore, the polarizing plate can suppress the reflection of external light not only in the front direction of the display surface of the organic EL display panel but also in the inclined direction. Therefore, by using this polarizing plate, an organic EL display panel having a wide viewing angle can be realized. Further, since the occurrence of orientation defects is usually suppressed in the liquid crystal alignment layer and the optical film, it is possible to suppress the occurrence of locations where reflection cannot be suppressed as intended.

The linear polarizer is, for example, a film obtained by adsorbing iodine or a dichroic dye on a polyvinyl alcohol film and then uniaxially stretching it in a boric acid bath; adsorbing iodine or a dichroic dye on the polyvinyl alcohol film. A film obtained by stretching and further modifying a part of polyvinyl alcohol units in the molecular chain to polyvinylene units; Further, as another example of the linear polarized light, there is a polarizer having a function of separating polarized light into reflected light and transmitted light, such as a grid polarized lighter and a multilayer polarized lighter. Of these, as the linear polarizer, a polarizer containing polyvinyl alcohol is preferable.

When natural light is incident on a linear polarizing element, only one polarized light is transmitted. The degree of polarization of this linear polarizer is not particularly limited, but is preferably 98% or more, more preferably 99% or more.
The thickness of the linear polarizer is preferably 5 μm to 80 μm.

When it is desired to make the polarizing plate function as a circular polarizing plate, the angle formed by the slow axis of the liquid crystal alignment layer or the optical film with respect to the polarization absorbing axis of the linear polarizing element is preferably 45 ° or an angle close to it. Specifically, the angle is preferably 45 ° ± 5 °, more preferably 45 ° ± 4 °, and particularly preferably 45 ° ± 3 °.

The polarizing plate may further include an arbitrary layer in addition to the linear polarizer, the liquid crystal alignment layer and the optical film. Examples of the optional layer include an adhesive layer for adhering a linear polarizer to a liquid crystal alignment layer or an optical film; a polarizer protective film layer for protecting the linear polarizer; and the like.

[5. Organic EL display panel]
The organic EL display panel according to the embodiment of the present invention includes the above-mentioned liquid crystal alignment layer or optical film. Usually, the organic EL display panel includes the above-mentioned polarizing plate including a liquid crystal alignment layer or an optical film. Such an organic EL display panel usually includes an organic EL element as a display element, and a polarizing plate is provided on the visible side of the organic EL element. Further, the polarizing plate is arranged so that a liquid crystal alignment layer or an optical film is provided between the organic EL element and the linear polarizer. Then, in such a configuration, the polarizing plate can function as a reflection suppression film.

Hereinafter, the mechanism of reflection suppression will be described by taking the case where the polarizing plate functions as a circular polarizing plate as an example. The light incident from the outside of the apparatus becomes circularly polarized light when only a part of the linearly polarized light passes through the linearly polarized light and then passes through the liquid crystal alignment layer or the optical film. Circularly polarized light is reflected by a component that reflects light in the organic EL display panel (reflecting electrode of the organic EL element, etc.), and passes through the liquid crystal alignment layer or the optical film again to obtain the vibration direction of the incident linearly polarized light. It becomes linearly polarized light having orthogonal vibration directions and does not pass through the linearly polarized light. Here, the vibration direction of linearly polarized light means the vibration direction of the electric field of linearly polarized light. As a result, the function of suppressing reflection is achieved. For the principle of such reflection suppression, Japanese Patent Application Laid-Open No. 9-127858 may be referred to.

An organic EL element usually includes a transparent electrode layer, a light emitting layer, and an electrode layer in this order, and the light emitting layer can generate light by applying a voltage from the transparent electrode layer and the electrode layer. Examples of the materials constituting the organic light emitting layer include polyparaphenylene vinylene-based materials, polyfluorene-based materials, and polyvinyl carbazole-based materials. Further, the light emitting layer may have a laminate of a plurality of layers having different emission colors, or a mixed layer in which a layer of a certain dye is doped with different dyes. Further, the organic EL element may include functional layers such as a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, an equipotential surface forming layer, and a charge generation layer.

Further, in the organic EL display panel, the liquid crystal alignment layer or the optical film may be provided for applications other than the reflection suppression film.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the examples shown below, and can be arbitrarily modified and implemented without departing from the scope of claims of the present invention and the equivalent scope thereof.

In the following description, "%" and "part" representing quantities are based on weight unless otherwise specified. Further, the operations described below were performed in the air at normal temperature and pressure unless otherwise specified.

Further, since the supporting base material contained in the intermediate film and the optical film produced in the examples and comparative examples described below has optical isotropic properties, it does not affect the measurement result of the retardation. Therefore, the measurement of the retardation in the examples and comparative examples described below was carried out using an intermediate film or an optical film containing a supporting base material as a sample.

[Evaluation methods]
(1. Thickness measurement method)
The thickness of the layer was measured using a film thickness meter (“F20-EXR” manufactured by Filmometry).

(2. How to measure the actual maximum tilt angle)
FIG. 4 is a perspective view for explaining a measurement direction when measuring the retardation of the liquid crystal alignment layer 300 from the inclination direction. In FIG. 4, the arrow A1 represents the in-plane slow axis direction of the liquid crystal alignment layer 300, the arrow A2 represents the in-plane phase advance axis direction of the liquid crystal alignment layer 300, and the arrow A3 represents the thickness direction of the liquid crystal alignment layer 300. Represents.

As shown in FIG. 4, the retardation of the liquid crystal alignment layer 300 was measured with an incident angle θ in the range of −50 ° to 50 ° using a phase difference meter (“AxoScan” manufactured by Axometrics). At this time, the measurement direction A4 was set perpendicular to the in-plane phase advance axis direction A2 of the liquid crystal alignment layer 300. The measurement wavelength was 590 nm.

From the measured retardation, the analysis software attached to the phase difference meter (analysis software "Multi-Layer Analysis" manufactured by AxoMetics; analysis conditions are analysis wavelength 590 nm, number of layer divisions 20 layers), the liquid crystal alignment layer. The substantially maximum tilt angle of the molecule of the liquid crystal compound contained in 300 was analyzed.

Further, the substantially maximum tilt angle of the molecules of the liquid crystal compound contained in the composite liquid crystal layer of the optical film is the above-mentioned liquid crystal orientation except that the retardation of the composite liquid crystal layer is measured instead of the retardation of the liquid crystal alignment layer. The measurement was carried out by the same method as the method for measuring the substantially maximum inclination angle of the molecules of the liquid crystal compound contained in the layer.
For the composite liquid crystal layer, the obtained substantially maximum inclination angle was evaluated according to the following criteria.
"A": The substantially maximum inclination angle of the composite liquid crystal layer is 40 ° or more and 85 ° or less.
"B": The substantially maximum inclination angle of the composite liquid crystal layer is 30 ° or more and less than 40 °.
"C": The substantially maximum tilt angle of the composite liquid crystal layer is less than 30 °.

(3. Method of measuring surface free energy)
The intermediate film was cut into a size of about 10 cm square to obtain a sample piece. On the surface of the sample piece opposite to the supporting base material of the liquid crystal alignment layer, the contact angle of pure water (H ₂ O) and the contact angle of diiodomethane (CH ₂ I ₂ ) were measured by an automatic contact angle meter. From the contact angle data measured in this way, the surface free energy of the surface of the liquid crystal alignment layer was calculated based on the theory of Owns-Wendt. The measurement conditions of the contact angle by the automatic contact angle meter were as follows.

<Contact angle measurement>
System: DropMaster700 (manufactured by Kyowa Interface Science)
AutoDispenser AD-31 (manufactured by Kyowa Interface Science)
Control analysis software: FAMAS ver3.13
Contact angle measurement method: θ / 2 method Temperature: 23 ° C
Number of measurements: n = 10 Average measurement value <Calculation method of surface free energy>
Analysis theory name: Owns-Wendt

(4. Evaluation method of coatability)
The optical film was visually observed. In this observation, it was investigated whether or not the liquid crystal inclined layer was not formed because the inclined layer composition was repelled by the liquid crystal oriented layer. Based on the observation results, the coatability of the inclined layer composition on the liquid crystal oriented layer was evaluated according to the following criteria.
"A": No repelling area is observed, and the workability is excellent.
"C": Poor coatability because some parts are repelled.

(5. Evaluation method of surface condition of composite liquid crystal layer)
A pair of linear polarizers (polarizer and analyzer) were stacked on the light table so as to form a paranicol. Here, the paranicol represents a mode in which the polarization transmission axes of the linear polarizers are parallel.
The optical film produced in Examples or Comparative Examples was cut into a 16 cm square size to obtain a film piece for measurement. This piece of film was placed between the linear polarizers placed on the light table as described above. At this time, the slow-phase axis of the film piece was set to form an angle of approximately 45 ° with respect to the absorption axis of the linear polarizer when viewed from the thickness direction. Then, it was visually observed. The surface condition of the composite liquid crystal layer was evaluated according to the following criteria according to the uniformity (uniformity of phase difference) in the observed image.
A: There is no unevenness in the observed image.
C: The observed image is uneven.

By the way, separately, the supporting base material used for producing the optical film was placed between the pair of linear polarizers installed on the light table and visually observed. As a result, when only the supporting base material without the composite liquid crystal layer was used instead of the film piece and observed, the entire surface was almost uniform and no unevenness was observed. From this result, it was confirmed that the unevenness observed in the above evaluation was caused by the surface condition of the composite liquid crystal layer.

(6. Evaluation method for orientation defects)
As a sample, an optical film containing a composite liquid crystal layer was prepared. The composite liquid crystal layer was permeated and observed under a cross Nicol using a polarizing microscope. At the time of this observation, the objective lens was set to 20 times. From the observation results, orientation defects were evaluated according to the following criteria.
"A": The entire surface is almost uniform, and no orientation defect is observed.
"C": Orientation defect is recognized.

(7. Evaluation method of reverse wavelength dispersibility)
In-plane retardation of the optical film (that is, retardation at an incident angle of 0 ° of the composite liquid crystal layer) was measured at measurement wavelengths of 450 nm and 550 nm using a phase difference meter (“AxoScan” manufactured by Axometrics). From the measured values of in-plane retardation Re (450) and Re (550) at the measured wavelengths of 450 nm and 550 nm, the inverse wavelength dispersibility of the optical film was evaluated according to the following criteria.
"A": Re (450) / Re (550) <0.9
"B": 0.9 ≤ Re (450) / Re (550) ≤ 1.0
"C": Re (450) / Re (550)> 1.0

(8. Evaluation method of viewing angle characteristics)
Using a phase difference meter (“AxoScan” manufactured by Axometrics), the retardation of the optical film was measured in the range of an incident angle θ of −50 ° to 50 °. At this time, the measurement direction was set perpendicular to the in-plane phase advance axis direction of the optical film. The measurement wavelength was 590 nm.

The average value R (± 50 °) of the retardation R (-50 °) at an incident angle θ of −50 ° and the retardation R (+ 50 °) at an incident angle θ of + 50 ° was calculated. Then, this average value R (± 50 °) is divided by the in-plane retardation R (0 °) at which the incident angle θ is 0 ° to obtain the average retardation ratio R (± 50 °) / R (0 °). I asked. The closer the average retardation ratio R (± 50 °) / R (0 °) is to 1.00, the better the viewing angle characteristics can be realized in the organic EL display panel. Therefore, based on the above-mentioned average retardation ratio R (± 50 °) / R (0 °), the viewing angle characteristics were evaluated according to the following criteria.
"A": 0.93 ≤ R (± 50 °) / R (0 °) ≤ 1.10
"B": 0.90 ≤ R (± 50 °) / R (0 °) <0.93
"C": R (± 50 °) / R (0 °) <0.90

(9. Method for confirming that the molecules of at least some liquid crystal compounds are inclined)
As a sample, a sample film (intermediate film or optical film) including a liquid crystal cured layer (liquid crystal oriented layer; or a composite liquid crystal layer composed of a liquid crystal oriented layer and a liquid crystal inclined layer) formed of a cured product of the liquid crystal composition was prepared. .. Using a phase difference meter (“AxoScan” manufactured by Axometrics), the retardation of the liquid crystal cured layer was measured in the range of an incident angle θ of −50 ° to 50 °. At this time, the measurement direction was set perpendicular to the in-plane phase advance axis direction of the liquid crystal cured layer. The measurement wavelength was 590 nm.

The retardation R (θ) of the liquid crystal cured layer at the measured incident angle θ is divided by the retardation R (0 °) of the liquid crystal cured layer at the incident angle 0 °, and the retardation ratio R (θ) / R. (0 °) was calculated. A graph was drawn with the obtained retardation ratio R (θ) / R (0 °) on the vertical axis and the incident angle θ on the horizontal axis. Then, based on whether or not the obtained graph is asymmetric with respect to θ = 0 °, the inclination orientation of the molecule was confirmed according to the following criteria.
“A”: Since the retardation ratio R (θ) / R (0 °) is asymmetric with respect to θ = 0 °, at least some molecules of the liquid crystal compound contained in the liquid crystal cured layer are the liquid crystal cured layer. Is inclined or oriented with respect to the layer plane (that is, with respect to the in-plane direction).
“C”: Since the retardation ratio R (θ) / R (0 °) is symmetrical with respect to θ = 0 °, all the molecules of the liquid crystal compound contained in the liquid crystal cured layer are the layers of the liquid crystal cured layer. Parallel or perpendicular to the plane (ie, in-plane).

[Example 1]
(Preparation of liquid crystal composition)
100 parts by weight of the reverse dispersion liquid crystal compound 1 having a polymerizable property represented by the following formula, 0.15 parts by weight of a fluorine-based surfactant (“S420” manufactured by AGC Seimi Chemical Co., Ltd.), and a photopolymerization initiator (manufactured by BASF). A liquid crystal composition was produced by mixing 4.3 parts by weight of "IrgacureOXE04") and 148.5 parts by weight of cyclopentanone and 222.8 parts by weight of 1,3-dioxolane as a solvent.

(Preparation of support base material)
As a supporting base material, a resin film made of a thermoplastic norbornene resin (“Zeonoa film ZF16” manufactured by Zeon Corporation; thickness 100 μm) having a masking film bonded to one side was prepared. The supporting substrate was an optically isotropic film without retardation. The masking film was peeled off from this supporting base material, and the masking peeled surface was subjected to corona treatment. Next, the corona-treated surface of the support base material was subjected to a rubbing treatment.

(Formation of liquid crystal alignment layer)
The liquid crystal composition was applied as an alignment layer composition on the rubbing-treated surface of the support base material using a wire bar to form a layer of the liquid crystal composition.
The layer of this liquid crystal composition was then heated in an oven set at 145 ° C. for 4 minutes to orient the liquid crystal compounds in the layer. The heating conditions were temperature conditions at which the residual viscosity of the test composition corresponding to the liquid crystal composition used was 170 cP.
Then, the layer of the liquid crystal composition was irradiated with ultraviolet rays of 500 mJ / cm ^{2 in} a nitrogen atmosphere to cure the layer of the liquid crystal composition to obtain a liquid crystal oriented layer having a thickness of 0.7 μm. As a result, an intermediate film containing a supporting base material and a liquid crystal alignment layer was obtained.
Using this intermediate film, the substantially maximum inclination angle of the liquid crystal alignment layer, the inclination orientation of the liquid crystal alignment layer, and the surface free energy of the surface of the surface opposite to the supporting base material of the liquid crystal alignment layer can be obtained by the above method. It was measured.

(Formation of liquid crystal inclined layer)
The surface of the liquid crystal alignment layer is coated with the remaining liquid crystal composition used for forming the liquid crystal alignment layer as an inclined layer composition by using a wire bar without applying a rubbing treatment to form a layer of the liquid crystal composition. Was formed.
Next, the layer of this liquid crystal composition was heated in an oven set at 145 ° C., which was the same as the step of forming the liquid crystal alignment layer, for 4 minutes to orient the liquid crystal compounds in the layer.
Then, the layer of the liquid crystal composition was irradiated with ultraviolet rays of 500 mJ / cm ^{2 in} a nitrogen atmosphere to cure the layer of the liquid crystal composition to obtain a liquid crystal inclined layer having a thickness of 2.4 μm.

As a result, an optical film including a support base material and a composite liquid crystal layer including a liquid crystal alignment layer and a liquid crystal inclined layer formed on the support base material was obtained.
Using the obtained optical film, the coatability of the inclined layer composition on the liquid crystal alignment layer, the surface state of the composite liquid crystal layer, the orientation defect, the substantially maximum inclination angle and the inclination orientation, and the inclination orientation, as described above, are used. The inverse wavelength dispersibility and viewing angle characteristics of the optical film were evaluated. The in-plane retardation of the optical film at a wavelength of 590 nm was 140 nm.

[Examples 2 and 3]
The thickness of the liquid crystal alignment layer and the thickness of the liquid crystal inclined layer were changed as shown in Table 1. Except for the above items, the same operation as in Example 1 was carried out to manufacture and evaluate an intermediate film containing a liquid crystal alignment layer and an optical film containing a composite liquid crystal layer. The in-plane retardation of the optical film of Example 2 at a wavelength of 590 nm was 145 nm. The in-plane retardation of the optical film of Example 3 at a wavelength of 590 nm was 155 nm.

[Example 4]
Instead of using 100 parts by weight of the reverse dispersion liquid crystal compound 1, 100 parts by weight of the reverse dispersion liquid crystal compound 2 having a polymerizable property represented by the following formula was used. Further, the thickness of the liquid crystal alignment layer and the thickness of the liquid crystal inclined layer were changed as shown in Table 1. Except for the above items, the same operation as in Example 1 was carried out to manufacture and evaluate an intermediate film containing a liquid crystal alignment layer and an optical film containing a composite liquid crystal layer.
In Example 4, the heating condition for heating the layer of the liquid crystal composition in the oven was a temperature condition in which the residual viscosity of the test composition corresponding to the liquid crystal composition used was 255 cP.
The in-plane retardation of the optical film at a wavelength of 590 nm was 148 nm.

[Comparative Example 1]
100 parts by weight of the polymerizable forward-dispersed liquid crystal compound 3 represented by the following formula, 0.15 parts by weight of a fluorine-based surfactant (“S420” manufactured by AGC Seimi Chemical Co., Ltd.), and a photopolymerization initiator (manufactured by BASF). A liquid crystal composition was produced by mixing 4.3 parts by weight of "IrgacureOXE04") and 148.5 parts by weight of cyclopentanone and 222.8 parts by weight of 1,3-dioxolane as a solvent.

A liquid crystal composition containing the above-mentioned forward-dispersed liquid crystal compound 3 was used as the alignment layer composition. Moreover, the thickness of the liquid crystal alignment layer was changed as shown in Table 2. Except for the above items, an intermediate film containing the liquid crystal alignment layer was produced and evaluated by the same operation as the step of forming the liquid crystal alignment layer in Example 1.

A liquid crystal composition containing a reverse-dispersed liquid crystal compound 1 on the surface of the liquid crystal alignment layer of the intermediate film thus obtained by the same operation as the step of forming the liquid crystal inclined layer of Example 1 except that the thickness of the liquid crystal inclined layer is changed. A liquid crystal inclined layer was formed using the above to obtain an optical film. The obtained optical film was evaluated by the method described above.

[Comparative Example 2]
The amount of the fluorine-based surfactant (“S420” manufactured by AGC Seimi Chemical Co., Ltd.) was changed from 0.15 parts by weight to 0.50 parts by weight. Further, the thickness of the liquid crystal alignment layer and the thickness of the liquid crystal inclined layer were changed as shown in Table 2. Except for the above items, the same operation as in Example 1 was carried out to manufacture and evaluate an intermediate film containing a liquid crystal alignment layer and an optical film containing a composite liquid crystal layer. However, with respect to the optical film, the coatability of the inclined layer composition on the liquid crystal alignment layer was poor, so evaluation items other than the coatability were not evaluated.

[Comparative Example 3]
Instead of 0.15 parts by weight of the fluorine-based surfactant (“S420” manufactured by AGC Seimi Chemical Co., Ltd.), 0.30 parts by weight of the fluorine-based surfactant (“Megafuck F562” manufactured by DIC) was used.
Further, the set temperature of the oven in the step of orienting the liquid crystal compound contained in the layer of the liquid crystal composition was changed to 110 ° C. This set temperature was a temperature at which the residual viscosity of the test composition corresponding to the liquid crystal composition became larger than 800 cP. As a result, the orientation direction of the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal alignment layer became parallel to the layer plane (that is, parallel to the in-plane direction).
Further, the thickness of the liquid crystal alignment layer and the thickness of the liquid crystal inclined layer were changed as shown in Table 2.
Except for the above items, the same operation as in Example 1 was carried out to manufacture and evaluate an intermediate film containing a liquid crystal alignment layer and an optical film containing a composite liquid crystal layer.

[Comparative Example 4]
A polyimide-based vertical alignment agent (“SE-4811” manufactured by Nissan Chemical Industries, Ltd.) was prepared in order to form an alignment film that orients the molecules of the liquid crystal compound perpendicularly to the layer plane.
A vertical alignment agent was applied by spin coating on a glass substrate as a supporting base material. The coated vertical alignment agent layer was dried on a hot plate at 80 ° C. for 2 minutes. Then, the layer of the vertical alignment agent was fired in an oven at 230 ° C. for 30 minutes to obtain an alignment film having a thickness of 100 nm. This alignment film corresponds to the liquid crystal alignment layer. Therefore, the surface free energy on the side opposite to the glass substrate of the alignment film was measured by the above method.

The surface of the alignment film was subjected to a rubbing treatment. The liquid crystal composition prepared in Example 1 was applied to the rubbing-treated surface using a wire bar to form a layer of the liquid crystal composition. With respect to the obtained liquid crystal composition layer, the orientation of the liquid crystal compound by heating in an oven and the liquid crystal composition by irradiation with ultraviolet rays were carried out under the same conditions as in the step of forming the liquid crystal inclined layer of Example 1. The layer was cured to obtain a liquid crystal cured layer having a thickness of 3.4 μm.

As a result, an optical member including a glass substrate and a composite layer including an alignment film and a liquid crystal curing layer formed on the glass substrate was obtained. The alignment film, the liquid crystal curing layer, the composite layer and the optical member correspond to the liquid crystal alignment layer, the liquid crystal inclined layer, the composite liquid crystal layer and the optical film. Therefore, the optical member was evaluated in the same manner as the optical film by the above method.

[Comparative Example 5]
An alignment substrate (manufactured by EHC) including a glass substrate and an alignment film formed on the glass substrate was prepared. The alignment film of the alignment substrate has a function of orienting the molecules of the liquid crystal compound perpendicularly to the layer plane on the alignment film, and is formed by a cetyltrimethylammonium bromide (CTAB) -based vertical alignment agent. ing. This alignment film corresponds to the liquid crystal alignment layer. Therefore, the surface free energy on the side opposite to the glass substrate of the alignment film was measured by the above method.

The surface of the alignment film was subjected to a rubbing treatment. The liquid crystal composition prepared in Example 1 was applied to the rubbing-treated surface using a wire bar to form a layer of the liquid crystal composition. With respect to the obtained liquid crystal composition layer, the orientation of the liquid crystal compound by heating in an oven and the liquid crystal composition by irradiation with ultraviolet rays were carried out under the same conditions as in the step of forming the liquid crystal inclined layer of Example 1. The layer was cured to obtain a liquid crystal cured layer having a thickness of 3.4 μm.

As a result, an optical member including a glass substrate and a composite layer including an alignment film and a liquid crystal curing layer formed on the glass substrate was obtained. The alignment film, the liquid crystal curing layer, the composite layer and the optical member correspond to the liquid crystal alignment layer, the liquid crystal inclined layer, the composite liquid crystal layer and the optical film. Therefore, the optical member was evaluated in the same manner as the optical film by the above method. However, since the coating property of the liquid crystal composition on the alignment film was poor with respect to this optical member, evaluation items other than the coating property were not evaluated.

[Comparative Example 6]
An alignment substrate (manufactured by EHC) including a glass substrate and an alignment film formed on the glass substrate was prepared. The alignment film of this alignment substrate has a function of aligning the molecules of the liquid crystal compound parallel to the layer plane on the alignment film, and is a polyimide-based horizontal alignment agent (Hitachi Kasei Co., Ltd. “LX-1400”. ") Is formed by. This alignment film corresponds to the liquid crystal alignment layer. Therefore, the surface free energy on the side opposite to the glass substrate of the alignment film was measured by the above method.

The liquid crystal composition prepared in Example 1 was applied to the surface of the alignment film using a wire bar to form a layer of the liquid crystal composition. With respect to the obtained liquid crystal composition layer, the orientation of the liquid crystal compound by heating in an oven and the liquid crystal composition by irradiation with ultraviolet rays were carried out under the same conditions as in the step of forming the liquid crystal inclined layer of Example 1. The layer was cured to obtain a liquid crystal cured layer having a thickness of 3.4 μm.

As a result, an optical member including a glass substrate and a composite layer including an alignment film and a liquid crystal curing layer formed on the glass substrate was obtained. The alignment film, the liquid crystal curing layer, the composite layer and the optical member correspond to the liquid crystal alignment layer, the liquid crystal inclined layer, the composite liquid crystal layer and the optical film. Therefore, the optical member was evaluated in the same manner as the optical film by the above method.

[result]
The results of the above-mentioned Examples and Comparative Examples are shown in Tables 1 and 2 below. In the table below, the meanings of the abbreviations are as follows.
Reverse dispersion 1: Reverse dispersion liquid crystal compound 1.
Reverse dispersion 2: Reverse dispersion liquid crystal compound 2.
Forward dispersion 3: Forward dispersion liquid crystal compound 3.
Non-liquid crystal A: Polyimide-based vertical alignment agent.
Non-liquid crystal B: CTAB-based vertical alignment agent.
Non-liquid crystal C: Polyimide-based horizontal alignment agent.

[Consideration]
As can be seen from Tables 1 and 2, in Comparative Examples 2 and 5, the inclined layer composition was repelled by the liquid crystal alignment layer or the alignment film, and the liquid crystal inclined layer could not be formed.
Further, in Comparative Example 1, since a forward-dispersed liquid crystal compound was used as the liquid crystal compound contained in the alignment layer composition, a retardation having a reverse wavelength dispersibility could not be obtained. Further, in Comparative Example 1, the substantially maximum inclination angle of the liquid crystal tilting layer is smaller than the substantially maximum inclination angle of the liquid crystal alignment layer. Therefore, the liquid crystal alignment layer formed by using the forward-dispersed liquid crystal compound as in Comparative Example 1 has the inclination angle of the molecule of the reverse-dispersed liquid crystal compound contained in the liquid crystal inclined layer formed on the liquid crystal oriented layer. It can be seen that it cannot exert the effect of increasing.
Further, in Comparative Examples 3, 4 and 6, the molecules of the inversely dispersed liquid crystal compound contained in the liquid crystal inclined layer could not be sufficiently inclined with respect to the layer plane (that is, with respect to the in-plane direction). Therefore, good viewing angle characteristics could not be realized.
On the other hand, in Examples 1 to 4, excellent results were obtained in all of coatability, reverse wavelength dispersibility and viewing angle characteristics. From this result, according to the present invention, it is possible to obtain an optical film having an in-plane retardation having a reverse wavelength dispersibility, being able to be produced while suppressing the cissing of the inclined layer composition, and having excellent viewing angle characteristics. confirmed.
Furthermore, in Examples 1 to 4, excellent results were obtained in both the surface condition and the orientation defect. Therefore, it has been confirmed that according to the present invention, an optical film having a composite liquid crystal layer having an excellent surface condition can be obtained by suppressing the occurrence of orientation defects.

100 Liquid crystal alignment layer 100U Specific surface of liquid crystal alignment layer 200 Optical film 210 Liquid crystal tilting layer 220 Composite liquid crystal layer 300 Liquid crystal alignment layer

Claims (10)

A liquid crystal alignment layer containing a molecule of the liquid crystal compound formed of a cured product of an alignment layer composition containing a liquid crystal compound capable of expressing birefringence of inverse wavelength dispersibility and having a fixed orientation state.
At least a part of the molecules of the liquid crystal compound contained in the liquid crystal alignment layer are inclined with respect to the layer plane of the liquid crystal alignment layer.
A liquid crystal alignment layer having a surface having a surface free energy of 40 mJ / m ² or more. The liquid crystal alignment layer according to claim 1, wherein the substantially maximum inclination angle of the molecule of the liquid crystal compound contained in the liquid crystal alignment layer is 15 ° or more and 60 ° or less. Curing of a gradient layer composition containing the liquid crystal alignment layer according to claim 1 or 2 and a liquid crystal compound capable of exhibiting birefringence having the same or different inverse wavelength dispersibility as the liquid crystal compound contained in the alignment layer composition. With a liquid crystal gradient layer formed of objects,
An optical film in which the liquid crystal inclined layer is in direct contact with the surface of the liquid crystal alignment layer. The optical film according to claim 3, wherein the in-plane retardation of the optical film at a measurement wavelength of 590 nm is 100 nm or more and 180 nm or less. A step of forming a layer of an oriented layer composition containing a liquid crystal compound capable of expressing birefringence of inverse wavelength dispersibility, and
A step of aligning the liquid crystal compound contained in the layer of the alignment layer composition, and
A step of curing the layer of the alignment layer composition to obtain a liquid crystal alignment layer, and the like.
At least a part of the molecules of the liquid crystal compound contained in the liquid crystal alignment layer are inclined with respect to the layer plane of the liquid crystal alignment layer.
A method for producing a liquid crystal oriented layer, wherein the liquid crystal oriented layer has a surface having a surface free energy of 40 mJ / m ² or more. The surface of the liquid crystal alignment layer according to claim 1 or 2 contains a liquid crystal compound capable of directly exhibiting birefringence having the same or different inverse wavelength dispersibility as the liquid crystal compound contained in the alignment layer composition. The process of forming the layer of the inclined layer composition and
A step of orienting the liquid crystal compound contained in the layer of the inclined layer composition, and
A method for producing an optical film, which comprises a step of curing a layer of the inclined layer composition to obtain a liquid crystal inclined layer. The step of forming the layer of the inclined layer composition directly on the surface of the liquid crystal alignment layer does not apply the rubbing treatment to the surface of the liquid crystal alignment layer, but directly on the surface of the liquid crystal alignment layer. The method for producing an optical film according to claim 6, which comprises forming a layer of a layer composition. A quarter wave plate comprising the liquid crystal alignment layer according to claim 1 or 2 or the optical film according to claim 3 or 4. A polarizing plate comprising the liquid crystal alignment layer according to claim 1 or 2 or the optical film according to claim 3 or 4. An organic electroluminescence display panel comprising the liquid crystal alignment layer according to claim 1 or 2 or the optical film according to claim 3 or 4.

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