WO2021166942A1 - Phase contrast film, circular-polarizing plate, and display device - Google Patents

Abstract

The present invention provides a phase difference film, a circular-polarizing plate, and a display device that exhibit reciprocal-wavelength dispersion properties and have an Nz coefficient around 0.50 (specifically, 0.40–0.60). The phase contrast film of the present invention has a substrate and a structural birefringent member disposed on the substrate. The structural birefringent member is formed such that a plurality of extending parts that extend in one direction are disposed periodically in a direction orthogonal to said one direction. The extending parts are formed by orienting and fixing a liquid crystal compound. The direction of the slow axis of the extending parts is substantially parallel to the one direction. The structural birefringent member satisfies condition 1 or 2. Condition 1: The liquid crystal compound exhibits reciprocal-wavelength dispersion properties. Condition 2: The period at which the extending parts are disposed is 700 nm or less.

Description

Phase difference film, circularly polarizing plate, display device

The present invention relates to a retardation film, a circularly polarizing plate, and a display device.

A retardation film having a refractive index anisotropy is applied to various applications such as an antireflection film for a display device and an optical compensation film for a liquid crystal display device.
From the viewpoint of application to various applications, it is required that the Nz coefficient of the retardation film is around 0.50 (specifically, about 0.40 to 0.60). Patent Document 1 discloses a retardation film containing a layer-separated structure that expresses structural birefringence as a retardation film that satisfies the Nz coefficient as described above.

International Publication No. 2018/221276

On the other hand, the retardation film is required to exhibit anti-wavelength dispersibility.
When the present inventor examined the characteristics of the retardation film described in Patent Document 1, it did not show reverse wavelength dispersibility, and further improvement was required.

In view of the above circumstances, the present invention provides a retardation film having an inverse wavelength dispersibility and an Nz coefficient of around 0.50 (specifically, 0.40 to 0.60). Make it an issue.
Another object of the present invention is to provide a circularly polarizing plate and a display device.

As a result of diligent studies on the problems of the prior art, the present inventors have found that the above problems can be solved by the following configuration.

(1) It has a substrate and a structural birefringent member arranged on the substrate.
The structural birefringent member is a member in which a plurality of extending portions extending in one direction are periodically arranged in a direction orthogonal to one direction.
The extending portion is a member formed by orienting and fixing the liquid crystal compound.
The direction of the slow axis of the extending part is substantially parallel to one direction,
A retardation film in which the structural birefringent member satisfies Requirement 1 or Requirement 2, which will be described later.
(2) The retardation film according to (1), wherein the ratio of the height of the extending portion to the period in which the extending portion is arranged is 1.00 to 2.00.
(3) The member according to (1) or (2), wherein the extending portion is a member formed by using a composition containing a liquid crystal compound having two or more polymerizable groups and exhibiting inverse wavelength dispersibility. Phase difference film.
(4) The retardation film according to any one of (1) to (3) and
A circularly polarizing plate having a polarizer.
(5) A display device having the retardation film according to any one of (1) to (3) or the circularly polarizing plate according to (4).

According to the present invention, it is possible to provide a retardation film having an inverse wavelength dispersibility and an Nz coefficient of around 0.50 (specifically, 0.40 to 0.60).
Further, according to the present invention, a circularly polarizing plate and a display device can be provided.

It is a schematic perspective view of one Embodiment of the retardation film of this invention. It is a yz cross-sectional view of the retardation film of FIG. It is an xz cross-sectional view at the position including the extending part of the retardation film of FIG. It is schematic cross-sectional view for demonstrating the method of manufacturing a retardation film. It is schematic cross-sectional view for demonstrating the method of manufacturing a retardation film. It is schematic cross-sectional view for demonstrating the method of manufacturing a retardation film. It is schematic cross-sectional view for demonstrating the method of manufacturing a retardation film.

Hereinafter, the present invention will be described in detail. The numerical range represented by using "-" in the present specification means a range including the numerical values before and after "-" as the lower limit value and the upper limit value. First, the terms used in the present specification will be described.

The slow axis is defined at 550 nm unless otherwise noted.
In the present invention, Re (λ) and Rth (λ) represent in-plane retardation and thickness direction retardation at wavelength λ, respectively. Unless otherwise specified, the wavelength λ is 550 nm.
In the present invention, Re (λ) and Rth (λ) are values measured at a wavelength λ in AxoScan (manufactured by Axometrics). By inputting the average refractive index ((nx + ny + nz) / 3) and film thickness (d (μm)) in AxoScan,
Slow phase axial direction (°)
Re (λ) = R0 (λ)
Rth (λ) = ((nx + ny) /2-nz) × d
Is calculated.
Although R0 (λ) is displayed as a numerical value calculated by AxoScan, it means Re (λ).

In the present specification, the refractive indexes nx, ny, and nz when measuring Re and Rth are Abbe refractometer (NAR-4T, manufactured by Atago Co., Ltd.), and a sodium lamp (λ =) is used as a light source. 589 nm) is used for measurement. Further, when measuring the wavelength dependence, it can be measured with a multi-wavelength Abbe refractometer DR-M2 (manufactured by Atago Co., Ltd.) in combination with an interference filter.
In addition, the values in the Polymer Handbook (JOHN WILEY & SONS, INC) and the catalogs of various optical films can be used. The average refractive index values of the main optical films are illustrated below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethylmethacrylate (1.49), And polystyrene (1.59).

Further, in the present specification, the Nz coefficient is a value given by Nz = (nx-nz) / (nx-ny).

The term "light" as used herein means active light or radiation, for example, the emission line spectrum of a mercury lamp, far ultraviolet rays typified by an excima laser, extreme ultraviolet rays (EUV light: Extreme Ultraviolet), X rays, ultraviolet rays, and the like. It also means an electron beam (EB: Electron Beam) or the like. Of these, ultraviolet rays are preferable.

In the present specification, "visible light" refers to light having a wavelength of 400 to 700 nm. Further, in the present specification, unless otherwise specified, the measurement wavelength is 550 nm.

The bonding direction of the divalent group (for example, -COO-) described in the present specification is not particularly limited. For example, when L in X-LY is -COO-, it is bonded to the X side. If the position is * 1 and the position connected to the Y side is * 2, L may be * 1-O-CO- * 2 or * 1-CO-O- * 2. May be good.

In the retardation film of the present invention, anti-wavelength dispersibility and an Nz coefficient in the vicinity of 0.5 are achieved by using a structural birefringent member that satisfies a predetermined requirement.

<Phase difference film>
Hereinafter, an embodiment of the retardation film of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic perspective view of an embodiment of the retardation film of the present invention. Further, FIG. 2 is a view showing a yz cross-sectional view (a partially enlarged view of the yz cross section) of the retardation film of FIG. 1, and FIG. 3 is a position including an extending portion of the retardation film of FIG. It is a figure which shows the xz cross-sectional view (partially enlarged view of the xz cross section).
As shown in FIG. 1, the retardation film 10 has a substrate 12 and a structural birefringent member 14 arranged on the substrate 12. The structural birefringent member 14 is composed of four extending portions 16. Each extending portion 16 extends in the x direction, and the extending portions 16 are periodically arranged in the y direction (the direction orthogonal to the extending direction of the extending portion 16).

In FIG. 1, only four extending portions 16 are described, but the number thereof is not particularly limited and may be more than four. The number of extending portions is preferably 10,000 or more, and more preferably 1,000,000 or more.
As shown in FIG. 1, the shapes of the plurality of extending portions 16 usually have the same shape, but the present invention is not limited to this embodiment, and the extending portions 16 may have different shapes.

In FIG. 1, the extending portion 16 extends in the x direction.
The shape of the extending portion 16 in the cross section (yz cross section) orthogonal to the extending direction is trapezoidal in FIG. That is, the extending portion 16 is a member that extends in one direction and has a trapezoidal cross section in a cross section orthogonal to the extending direction. The cross-sectional shape of the extending portion is not limited to this aspect, and may be, for example, a rectangular shape or a semicircular shape.
When the cross-sectional shape of the extending portion 16 in the cross section orthogonal to the extending direction is trapezoidal, the side 16a of the extending portion 16 on the substrate side (the extending portion 16 in the cross section) as shown in FIG. The size of the angle θ1 formed by the side in contact with the substrate 12) and the hypotenuse 16b is not particularly limited, but is preferably 70 to 90 °, more preferably 80 to 90 °.

As shown in FIGS. 1 and 2, the extending portions 16 are arranged at predetermined intervals P along the y direction. The period P corresponds to the distance between the centers of the extending portions 16. The center of the extending portion 16 means the center position of the extending portion 16 (the center position in the width direction of the extending portion 16) in the direction orthogonal to the extending direction of the extending portion 16.
As shown in FIG. 2, the ratio of the height H of the extending portion to the period P in which the extending portion 16 is arranged (height of the extending portion / period in which the extending portion is arranged) is inverse wavelength dispersion. From 1.00 to 1.00 to the point that the effect of at least one of the point where the property is more excellent and the point where the Nz coefficient is closer to 0.5 can be obtained (hereinafter, also simply referred to as "the point where the effect of the present invention is more excellent"). 2.00 is preferable, and 1.00 to 1.80 is more preferable.

The height H of the extending portion 16 is not particularly limited, but 300 to 1000 nm is preferable, and 500 to 800 nm is more preferable, from the viewpoint that the effect of the present invention is more excellent.
The period P of the extending portion 16 is not particularly limited, but 700 nm or less is preferable, and 600 nm or less is more preferable, from the viewpoint that the effect of the present invention is more excellent. The lower limit is preferably 200 nm or more, more preferably 300 nm or more.
As will be described in detail later, the retardation film may satisfy the following requirement 2.
Requirement 2: The period in which the extending portion is arranged is 700 nm or less.

The maximum width in the cross section orthogonal to the extending direction of the extending portion 16 is not particularly limited, but 200 to 650 nm is preferable, and 250 to 600 nm is more preferable from the viewpoint of more excellent effect of the present invention.
The maximum width corresponds to the largest width of the extending portion along the direction parallel to the substrate in a cross section orthogonal to the extending direction of the extending portion. For example, the extending portion 16 is shown in FIG. In the case of the trapezoidal shape as shown, the length of the side 16a corresponds to the maximum width.

The retardation film satisfies the requirements specified in the first embodiment or the second embodiment described later.

The retardation film of the present invention is a member in which the extending portion is formed by orienting and fixing the liquid crystal compound, and the extending portion extends in the direction of the slow phase axis (in-plane slow phase axis) of the extending portion. The structural birefringent member, which is substantially parallel to the existing one direction, satisfies the following requirement 1 or 2.
Requirement 1: The liquid crystal compound is a liquid crystal compound exhibiting reverse wavelength dispersibility.
Requirement 2: The period in which the extending portion is arranged is 700 nm or less.
Hereinafter, the above aspect will be described in detail.

In the retardation film of the present invention, the extending portion is a member formed by aligning and fixing the liquid crystal compound, and the direction of the slow axis of the extending portion is substantially parallel to one direction in which the extending portion extends. Is.
Hereinafter, a case where the liquid crystal compound is a rod-shaped liquid crystal compound will be described as an example.
FIG. 3 is an xz cross-sectional view (partially enlarged view) of the extending portion of the retardation film 10. The extending portion 16 shown in FIG. 3 is a member formed by aligning and fixing the liquid crystal compound LC. In FIG. 3, the extending portion 16 is a member formed by fixing a rod-shaped liquid crystal compound that is homogenically oriented. That is, it is a member that fixes the orientation state of the rod-shaped liquid crystal compound that is homogenically oriented.
The "fixed" state is a state in which the orientation of the liquid crystal compound is maintained. Specifically, in the temperature range of 0 to 50 ° C., and more severely, -30 to 70 ° C., the member has no fluidity, and the orientation form is changed by an external field or an external force. It is preferable that the state is such that the fixed orientation form can be kept stable.

In the present specification, the homogeneous orientation is a state in which the molecular axes of the liquid crystal compound (for example, the major axis in the case of a rod-shaped liquid crystal compound) are arranged horizontally and in the same direction with respect to the member surface (for example). Optical uniaxiality).
Here, the term "horizontal" does not require that the liquid crystal compound be strictly horizontal, but means an orientation in which the inclination angle formed by the average molecular axis of the liquid crystal compound with the surface of the member is less than 20 °.
Further, the same direction does not require that the directions are exactly the same, and when the directions of the slow axis are measured at any 20 positions in the plane, the slow axes at 20 points are measured. It is assumed that the maximum difference between the slow axis orientations of the two slow axis orientations (the difference between the two slow axis orientations having the maximum difference among the 20 slow axis orientations) is less than 10 °. ..

Further, in FIG. 3, the direction of the slow axis of the extending portion 16 is substantially parallel to the one direction (x direction) in which the extending portion 16 extends.
Approximately parallel means that the angle (acute angle) formed by the direction of the slow axis of the extending portion 16 and the extending direction of the extending portion 16 is within a range of 5 ° or less (within a range of 0 to 5 °). It is preferable that the temperature is within the range of 3 ° or less (within the range of 0 to 3 °).
The method of measuring the direction of the slow axis of the extending portion is as follows.
An optically isotropic material (for example, an isotropic liquid such as immersion oil, or a cured product obtained by filling a transparent and curable liquid composition and then curing. As a transparent and curable liquid composition. (Preferably, an acrylate composition or an epoxy composition, which can be used as a transparent ultraviolet curable adhesive) is filled between the extending portions, and then a polarization Raman measurement method is performed to obtain the extending portion. The direction of the slow axis can be obtained. More specifically, the polarized Raman measurement is performed by setting the excitation laser wavelength to 785 nm and the excitation laser output to about 30 mW in the sample portion using NanoFinder30 manufactured by Tokyo Instruments. The angle formed by the orientation of the surface of the sample on which the laser polarization is incident and the direction of the electric field of the incident laser polarization is changed from 0 ° to 180 ° in 15 ° increments, and the polarized light parallel to the incident laser polarization electric field is measured. The component (I parallel) and the perpendicular polarization component (I vertical) are spectrally detected using an analyzer. Furthermore, for bands with peaks derived from the molecular skeleton, fitting analysis based on the least squares method was performed using the second-order orientation parameter and the fourth-order orientation parameter as variables using a theoretically derived equation, and the slow axis. Get direction.

Further, in the first embodiment, the structural birefringent member satisfies the above-mentioned requirement 1 or requirement 2. If the above requirement 1 or requirement 2 is satisfied, the inverse wavelength dispersibility of the retardation film is achieved.

Requirement 1 means that the liquid crystal compound constituting the extending portion is a liquid crystal compound exhibiting reverse wavelength dispersibility.
In the present specification, the term "liquid crystal compound exhibiting reverse wavelength dispersibility" means that the in-plane retardation (Re) value at a specific wavelength (visible light range) of an optically anisotropic film prepared using this compound is measured. At that time, it means a compound that satisfies the relationship between the following formulas (A) and (B).
Formula (A) Re (450) / Re (550) <1.00
Equation (B) Re (650) / Re (550) ≧ 1.00
Re (450) represents the in-plane retardation of the optically anisotropic film at a wavelength of 450 nm, Re (550) represents the in-plane retardation of the optically anisotropic film at a wavelength of 550 nm, and Re (650) represents the optical difference at a wavelength of 650 nm. Represents in-plane retardation of anisotropic membrane.
Specific examples of the liquid crystal compound exhibiting reverse wavelength dispersibility will be described in detail later.
The liquid crystal compound exhibiting forward wavelength dispersibility is as follows when the in-plane retardation (Re) value at a specific wavelength (visible light range) of an optically anisotropic film produced using this compound is measured. It means a compound that satisfies the relationship between the formula (E) and the formula (F) of.
Equation (E) Re (450) / Re (550) ≧ 1.00
Equation (F) Re (650) / Re (550) <1.00

Further, Requirement 2 means that the period of the extending portion arranged periodically is 700 nm or less. The period of the extending portion is preferably 700 nm or less, more preferably 600 nm or less. Regarding the lower limit, 200 nm or more is preferable, and 300 nm or more is more preferable.
When the period of the extending portion is 700 nm or less, the period of the extending portion and the wavelength of light in the visible light region are as large as each other. In such a case, a difference in refractive index between the x-direction and the y-direction of the structural birefringent member is likely to occur due to the influence of the extending portion for light having a longer wavelength. Therefore, for example, the difference in refractive index between the x-direction and the y-direction of the structural birefringent member at a wavelength of 650 nm becomes larger than the difference in refractive index between the x-direction and the y-direction of the structural birefringent member at a wavelength of 450 nm. Reverse wavelength dispersibility is achieved.

Further, the substrate and the extending portion may be made of the same material. That is, the substrate and the extending portion may be integrally formed instead of being made of separate members.

<Manufacturing method of retardation film>
The method for producing the above-mentioned retardation film is not particularly limited, and a known method is adopted.
Examples of the method for producing a retardation film include a so-called imprint method and a mask exposure method.
Specifically, as an imprint method, a composition containing a liquid crystal compound is applied onto a substrate to form a coating film, the liquid crystal compound in the coating film is oriented, and then a mold having an uneven structure on the surface is formed. Is pressed against the coating film to transfer the uneven structure of the mold to the coating film to form a structural birefringent member on the substrate.
Specifically, as a mask exposure method, a composition containing a liquid crystal compound having a polymerizable group is applied onto a substrate to form a coating film, the liquid crystal compound in the coating film is oriented, and then a predetermined pattern is used. A method of forming a structural birefringent member on a substrate by exposing a coating film through the mask of the above and removing an unexposed portion can be mentioned.
From the viewpoint of productivity, the imprint method is preferable. Hereinafter, the imprint method will be described in detail.

The imprint method has the following steps.
Step 1: A composition containing a liquid crystal compound is applied onto a substrate to form a coating film. Step 2: A step of orienting a liquid crystal compound in the coating film. Step 3: A mold having an uneven structure on the surface is used as a coating film. Step of pressing and transferring the uneven structure of the mold to the coating film When the liquid crystal compound used has a polymerizable group, it is preferable to carry out the following step 4 after step 3.
Step 4: A step of curing the coating film to which the uneven structure of the mold is transferred The procedure of each step and the material used will be described in detail below.

(Step 1)
Step 1 is a step of applying a composition containing a liquid crystal compound on a substrate to form a coating film. By carrying out this step, as shown in FIG. 4, the coating film 18 is formed on the substrate 12.
In the following, first, the members and materials used will be described in detail.

The substrate used is a member that functions as a substrate for applying the composition. The substrate may be a so-called temporary substrate (temporary support).
Examples of the substrate (temporary substrate) include a plastic substrate and a glass substrate. Examples of the material constituting the plastic substrate include polyester resin such as polyethylene terephthalate, polycarbonate resin, (meth) acrylic resin, epoxy resin, polyurethane resin, polyamide resin, polyolefin resin, cellulose resin, silicone resin, and polyvinyl alcohol. ..
The thickness of the substrate may be about 5 to 1000 μm, preferably 10 to 250 μm, and more preferably 15 to 90 μm.

If necessary, an alignment film may be arranged on the substrate.
The alignment film generally contains a polymer as a main component. The polymer for an alignment film has been described in a large number of documents, and a large number of commercially available products are available. As the polymer for the alignment film, polyvinyl alcohol, polyimide, or a derivative thereof is preferable.
It is preferable that the alignment film is subjected to a known rubbing treatment.
Further, as the alignment film, a photoalignment film may be used.
The thickness of the alignment film is preferably 0.01 to 10 μm, more preferably 0.01 to 1 μm.

The type of liquid crystal compound is not particularly limited. Generally, a liquid crystal compound can be classified into a rod-shaped type (rod-shaped liquid crystal compound) and a disk-shaped type (discotic liquid crystal compound) according to its shape. Further, the liquid crystal compound can be classified into a small molecule type and a high molecular type. A polymer generally refers to a polymer having a degree of polymerization of 100 or more (Polymer Physics / Phase Transition Dynamics, Masao Doi, p. 2, Iwanami Shoten, 1992). In the present invention, any liquid crystal compound can be used, but it is preferable to use a rod-shaped liquid crystal compound or a discotic liquid crystal compound, and it is more preferable to use a rod-shaped liquid crystal compound. Two or more kinds of rod-shaped liquid crystal compounds, two or more kinds of discotic liquid crystal compounds, or a mixture of a rod-shaped liquid crystal compound and a discotic liquid crystal compound may be used.
Examples of the rod-shaped liquid crystal compound include the liquid crystal compounds described in claim 1 of JP-A No. 11-513019 and paragraphs 0026 to 0098 of JP-A-2005-289980.
Examples of the discotic liquid crystal compound include the liquid crystal compounds described in paragraphs 0020 to 0067 of JP-A-2007-108732 and paragraphs 0013 to 0108 of JP-A-2010-2404038.

The liquid crystal compound preferably has a polymerizable group. That is, the liquid crystal compound is preferably a polymerizable liquid crystal compound. When the liquid crystal compound has a polymerizable group, the orientation state of the liquid crystal compound can be easily fixed by the curing treatment described later.
The type of polymerizable group contained in the liquid crystal compound is not particularly limited, a functional group capable of an addition polymerization reaction is preferable, a polymerizable ethylenically unsaturated group or a ring-polymerizable group is more preferable, and a (meth) acryloyl group or a vinyl group is preferable. , Styryl group, or allyl group is more preferable.
The number of polymerizable groups contained in the liquid crystal compound is not particularly limited, but is preferably 2 or more. The upper limit is not particularly limited, but it is often 10 or less.

The liquid crystal compound preferably exhibits reverse wavelength dispersibility, and more preferably a liquid crystal compound having two or more polymerizable groups and exhibiting reverse wavelength dispersibility.

As the liquid crystal compound, a polymerizable liquid crystal compound represented by the formula (X) is preferable.
The polymerizable liquid crystal compound represented by the formula (X) is a compound exhibiting liquid crystallinity.
L _1- G _1- D _1- Ar-D _2- G _2- L ₂ ... (X)

In formula (X), D ₁ and D ₂ are independently single-bonded, -O-, -CO-, -CO-O-, -C (= S) O-, -CR ¹ R ^2- , respectively. ^{-CR 1 R 2 -CR 3 R 4} -, - O-CR 1 R 2 -, - CR 1 R 2 -O-CR 3 R 4 -, - CO-O-CR 1 R 2 -, - O-CO ^{-CR 1 R 2 -, - CR} 1 R 2 -CR 3 R 4 -O-CO -, - CR 1 R 2 -O-CO-CR 3 R 4 -, - CR 1 R 2 -CO-O-CR ^{3 R 4 -, - NR 1} -CR 2 R 3 -, or, -CO-NR ¹ - represents a.
R ¹ , R ² , R ³ and R ⁴ independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms. When each of R ¹ , R ² , R ³ and R ⁴ exists, the plurality of R ¹ , the plurality of R ² , the plurality of R ³ and the plurality of R ⁴ may be the same or different from each other. good.
G ₁ and G ₂ are each independently a divalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, a group formed by linking a plurality of the alicyclic hydrocarbon groups, an aromatic hydrocarbon group, or an aromatic hydrocarbon group. , Representing a group formed by linking a plurality of the aromatic hydrocarbon groups, even if the methylene group contained in the alicyclic hydrocarbon group is substituted with -O-, -S-, or -NH-. good.
The group formed by linking a plurality of the alicyclic hydrocarbon groups means a group formed by connecting divalent alicyclic hydrocarbon groups having 5 to 8 carbon atoms in a single bond. Further, the group formed by linking the plurality of the aromatic hydrocarbon groups means a group formed by connecting the aromatic hydrocarbon groups with a single bond.
L ₁ and L ₂ each independently represent a monovalent organic group, and at least one selected from the group consisting of _{L 1} and L _{2 represents a monovalent group having a polymerizable group.}
Ar represents any aromatic ring selected from the group consisting of groups represented by the formulas (Ar-1) to (Ar-7).

In the above formula (Ar-1), Q ¹ represents N or CH, Q ² represents -S-, -O-, or -N (R ⁷ )-, and R ⁷ is a hydrogen atom or Representing an alkyl group having 1 to 6 carbon atoms, Y ¹ represents an aromatic hydrocarbon group having 6 to 12 carbon atoms or an aromatic heterocyclic group having 3 to 12 carbon atoms, which may have a substituent. show.
Examples of the alkyl group having 1 to 6 carbon atoms indicated by R ⁷ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group and an n-pentyl group. Groups and n-hexyl groups can be mentioned.
Examples of the aromatic hydrocarbon group having 6 to 12 carbon atoms indicated by Y ¹ include an aryl group such as a phenyl group, a 2,6-diethylphenyl group, and a naphthyl group.
Examples of the aromatic heterocyclic group having 3 to 12 carbon atoms indicated by Y ¹ include heteroaryl groups such as a thienyl group, a thiazolyl group, a frill group, and a pyridyl group.
Further ^{, examples of the substituent that Y 1} may have include an alkyl group, an alkoxy group, and a halogen atom.
The alkyl group is preferably an alkyl group having 1 to 18 carbon atoms, and an alkyl group having 1 to 8 carbon atoms (for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group). Groups, t-butyl groups, and cyclohexyl groups) are more preferred, alkyl groups having 1 to 4 carbon atoms are even more preferred, and methyl or ethyl groups are particularly preferred. The alkyl group may be linear, branched, or cyclic.
As the alkoxy group, for example, an alkoxy group having 1 to 18 carbon atoms is preferable, and an alkoxy group having 1 to 8 carbon atoms (for example, a methoxy group, an ethoxy group, an n-butoxy group, and a methoxyethoxy group) is more preferable. An alkoxy group having 1 to 4 carbon atoms is more preferable, and a methoxy group or an ethoxy group is particularly preferable.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and among them, a fluorine atom or a chlorine atom is preferable.

Further, in the above formulas (Ar-1) to (Ar-7), Z ¹ , Z ² and Z ³ are independently hydrogen atoms, monovalent aliphatic hydrocarbon groups having 1 to 20 carbon atoms, and carbons, respectively. A monovalent alicyclic hydrocarbon group having a number of 3 to 20, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, -OR ⁸ , -NR ⁹ R ¹⁰ , or , -SR ¹¹ and R ⁸ to R ¹¹ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Z ¹ and Z ² may be bonded to each other to form an aromatic ring. good.
As the monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alkyl group having 1 to 15 carbon atoms is preferable, an alkyl group having 1 to 8 carbon atoms is more preferable, and a methyl group, an ethyl group, an isopropyl group, and tert are preferable. -Pentyl group (1,1-dimethylpropyl group), tert-butyl group, or 1,1-dimethyl-3,3-dimethyl-butyl group is more preferable, and methyl group, ethyl group, or tert-butyl group. Is particularly preferable.
Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, a methylcyclohexyl group, and the like. Monocyclic saturated hydrocarbon groups such as ethylcyclohexyl group; cyclobutenyl group, cyclopentenyl group, cyclohexenyl group, cycloheptenyl group, cyclooctenyl group, cyclodecenyl group, cyclopentadienyl group, cyclohexadienyl group, cyclooctadienyl group, And monocyclic unsaturated hydrocarbon groups such as cyclodecadien; bicyclo [2.2.1] heptyl group, bicyclo [2.2.2] octyl group, tricyclo [5.2.1.0 ^2,6 ] Decyl group, tricyclo [3.3.1.1 ^3,7 ] decyl group, tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] Dodecyl group, polycyclic saturated hydrocarbon group such as adamantyl group; and the like.
Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include a phenyl group, a 2,6-diethylphenyl group, a naphthyl group, and a biphenyl group, and an aryl group having 6 to 12 carbon atoms (an aryl group having 6 to 12 carbon atoms). Especially phenyl group) is preferable.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and among them, a fluorine atom, a chlorine atom, or a bromine atom is preferable.
Examples of the alkyl group having 1 to 6 carbon atoms represented by R ⁸ to R ¹¹ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. Examples thereof include an n-pentyl group and an n-hexyl group.

Further, in the above formulas (Ar-2) and (Ar-3), A ¹ and A ² are independently derived from -O-, -N (R ¹² )-, -S-, and -CO-, respectively. Represents a group selected from the group, where R ¹² represents a hydrogen atom or substituent.
Examples of the substituent represented by R ^{12 include the same substituents that Y 1} in the above formula (Ar-1) may have.

Further, in the above formula (Ar-2), X represents a non-metal atom of Group 14 to 16 to which a hydrogen atom or a substituent may be bonded.
Examples of the non-metal atoms of Groups 14 to 16 indicated by X include an oxygen atom, a sulfur atom, a nitrogen atom having a substituent, and a carbon atom having a substituent. Examples of the substituent include a carbon atom having a substituent. , Alkyl group, alkoxy group, alkyl substituted alkoxy group, cyclic alkyl group, aryl group (for example, phenyl group and naphthyl group), cyano group, amino group, nitro group, alkylcarbonyl group, sulfo group, and hydroxyl group. Can be mentioned.

Further, in the above formula (Ar-3), D ⁴ and D ⁵ are independently single-bonded or -CO-, -O-, -S-, -C (= S)-, -CR ^1a. R ^2a- , -CR ^3a = CR ^4a- , -NR ^5a- , or a divalent linking group consisting of a combination of two or more of these, and R ^1a to R ^5a are independent hydrogen atoms, respectively. It represents a fluorine atom or an alkyl group having 1 to 4 carbon atoms.
Here, examples of the divalent linking group, for example, -CO -, - O -, - CO-O -, - C (= S) O -, - CR 1b R 2b -, - CR 1b R 2b -CR ^{1b R 2b -, - O-} CR 1b R 2b -, - CR 1b R 2b -O-CR 1b R 2b -, - CO-O-CR 1b R 2b -, - O-CO-CR 1b R 2b -, ^{-CR 1b R 2b -O-CO-} CR 1b R 2b -, - CR 1b R 2b -CO-O-CR 1b R 2b -, - NR 3b -CR 1b R 2b -, and, ^{-CO-NR 3b} - Can be mentioned. R ^1b , R ^2b and R ^3b independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 4 carbon atoms.

Further, in the above formula (Ar-3), SP ¹ and SP ² are independently single-bonded, linear or branched alkylene groups having 1 to 12 carbon atoms, or 1 to 12 carbon atoms. _{One or more of -CH 2-} constituting the linear or branched alkylene group was replaced with -O-, -S-, -NH-, -N (Q)-, or -CO-. It represents a divalent linking group and Q represents a substituent. Examples of the substituent include the same substituents that Y ¹ in the above formula (Ar-1) may have.
Here, examples of the linear or branched alkylene group having 1 to 12 carbon atoms include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a methylhexylene group, and the like. A petitene group is preferred.

Further, in the above formula (Ar-3), L ³ and L ⁴ each independently represent a monovalent organic group.
Examples of the monovalent organic group include an alkyl group, an aryl group, and a heteroaryl group. The alkyl group may be linear, branched or cyclic, but linear is preferred. The number of carbon atoms of the alkyl group is preferably 1 to 30, more preferably 1 to 20, and even more preferably 1 to 10. The aryl group may be monocyclic or polycyclic, but monocyclic is preferable. The aryl group preferably has 6 to 25 carbon atoms, more preferably 6 to 10 carbon atoms. Further, the heteroaryl group may be monocyclic or polycyclic. The number of heteroatoms constituting the heteroaryl group is preferably 1 to 3. The hetero atom constituting the heteroaryl group is preferably a nitrogen atom, a sulfur atom, or an oxygen atom. The heteroaryl group preferably has 6 to 18 carbon atoms, more preferably 6 to 12 carbon atoms. Further, the alkyl group, the aryl group, and the heteroaryl group may be unsubstituted or have a substituent. Examples of the substituent include the same substituents that Y ¹ in the above formula (Ar-1) may have.

Further, in the above formulas (Ar-4) to (Ar-7), Ax has at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocycle, and has 2 to 30 carbon atoms. Represents an organic group.
Further, in the above formulas (Ar-4) to (Ar-7), Ay is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, or an aromatic hydrocarbon ring and aromatic. Represents an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of group heterocycles.
Here, the aromatic rings in Ax and Ay may have a substituent, and Ax and Ay may be bonded to each other to form a ring.
Further, Q ³ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.
Examples of Ax and Ay include those described in paragraphs [0039] to [0995] of Patent Document 2 (International Publication No. 2014/010325).
The alkyl group having 1 to 6 carbon atoms represented by ^{Q 3,} for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, n- butyl group, isobutyl group, sec- butyl group, tert- butyl radical, n -Pentyl group and n-hexyl group can be mentioned, and examples of the substituent include the same substituents that Y ¹ in the above formula (Ar-1) may have.

For the definition and preferable range of each substituent of the liquid crystal compound represented by the formula (X), refer to D ¹ , D ² , G ¹ , G ² , L relating to the compound (A) described in JP2012-021068. ¹ , L ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , X ¹ , Y ¹ , Q ¹ , Q ² are described as D ₁ , D ₂ , G ₁ , G ₂ , L ₁ , L ₂ , respectively. R ¹ , R ² , R ³ , R ⁴ , Q ₁ , Y ₁ , Z ₁ , and Z ₂ can be referred to, and the compound represented by the general formula (I) described in JP-A-2008-107767 can be referred to. a _{1, a 2,} and _a 1 a description of X respectively, _{a 2,} and X can refer for, Ax of the compound represented by the general formula described in WO 2013/018526 (I), Ay, The ^{description regarding Q 1} can be referred to for Ax, Ay, and Q ^{3, respectively.} For Z ₃ can refer to the description for ^{Q 1} relates to compounds (A) described in JP-A-2012-021068.

In particular, the organic group _{represented by L 1} and L ₂ is preferably a group represented by _{-D 3-} G _3- Sp-P _{3, respectively.}
D ₃ is synonymous with _{D 1.}
G ₃ is a single bond, a divalent aromatic ring group or heterocyclic group having 6 to 12 carbon atoms, a group formed by linking a plurality of the aromatic ring groups or heterocyclic groups, and a divalent aromatic ring group having 5 to 8 carbon atoms. It represents an alicyclic hydrocarbon group or a group formed by linking a plurality of the alicyclic hydrocarbon groups, and the methylene group contained in the alicyclic hydrocarbon group is -O-, -S- or NR. It may be substituted with ^{7 −, where R 7} represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
The group in which the plurality of aromatic ring groups or heterocyclic groups are linked means a group in which divalent aromatic ring groups or heterocyclic groups having 6 to 12 carbon atoms are linked by a single bond. The group in which a plurality of the alicyclic hydrocarbon groups are linked means a group in which divalent alicyclic hydrocarbon groups having 5 to 8 carbon atoms are linked by a single bond.
The G _3, preferred group wherein two cyclohexane rings are linked via a single bond.
Sp is a single bond,-(CH ₂ ) _n -,-(CH ₂ ) _n- O-,-(CH _2- O-) _n -,-(CH ₂ CH _2- O-) _m , -O- (CH ₂ ) _n- , -O- (CH ₂ ) _n- O-, _{-O- (CH 2-} O-) _n- , -O- (CH ₂ CH _2- O-) _m , -C (= O) -O- (CH ₂ ) _n- , -C (= O) -O- (CH ₂ ) _n- O-, -C (= O) -O- (CH _2- O-) _n -,- _{C (= O) -O- (CH} 2 CH 2 -O-) m, -C (= O) -N (R 8) - (CH 2) n -, - C (= O) -N (R 8 )-(CH ₂ ) _n -O-, -C (= O) -N (R ⁸ )-(CH _2- O-) _n- , -C (= O) -N (R ⁸ )-(CH ₂₎ Spacer represented by CH _2- O-) _m or-(CH ₂ ) _n- O- (C = O)-(CH ₂ ) _n- C (= O) -O- (CH ₂ ) _n- Represents a group. Here, n represents an integer of 2 to 12, m represents an integer of 2 to 6, and R ⁸ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Further, -CH 2 in the above group _- hydrogen atoms may be substituted with a methyl group.
P ₃ represents a polymerizable group.

The polymerizable group is not particularly limited, but a polymerizable group capable of radical polymerization or cationic polymerization is preferable.
Examples of the radically polymerizable group include known radically polymerizable groups, and an acryloyl group or a methacryloyl group is preferable.
Examples of the cationically polymerizable group include known cationically polymerizable groups, and examples thereof include an alicyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiroorthoester group, and a vinyloxy group. Of these, an alicyclic ether group or a vinyloxy group is preferable, and an epoxy group, an oxetanyl group, or a vinyloxy group is more preferable.
Examples of particularly preferable polymerizable groups include the following.

In the present specification, the "alkyl group" may be linear, branched or cyclic, and may be, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group or an isobutyl group. , Se-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, 1,1-dimethylpropyl group, n-hexyl group, isohexyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, and Cyclohexyl group can be mentioned.

The content of the liquid crystal compound in the composition is not particularly limited, but is preferably 50% by mass or more, more preferably 70% by mass or more, based on the total solid content in the liquid crystal composition. The upper limit is not particularly limited, but in many cases, it is 90% by mass or less.
The solid content means a component capable of forming a structural birefringent member from which the solvent has been removed, and is a solid content even if the property is liquid.

The composition may contain components other than the liquid crystal compound.
The composition may contain a solvent. Examples of the solvent include ester-based solvents, ether-based solvents, amide-based solvents, carbonate-based solvents, ketone-based solvents, aliphatic hydrocarbon-based solvents, alicyclic hydrocarbon-based solvents, aromatic hydrocarbon-based solvents, and halogenation. Examples include carbon-based solvents, water, and alcohol-based solvents.

In addition, the composition may contain a polymerization initiator. When the composition contains a polymerization initiator, the polymerization of the liquid crystal compound having a polymerizable group proceeds more efficiently.
Examples of the polymerization initiator include known polymerization initiators, photopolymerization initiators and thermal polymerization initiators, and photopolymerization initiators are preferable.
The content of the polymerization initiator in the composition is not particularly limited, but is preferably 0.01 to 20% by mass, more preferably 0.5 to 10% by mass, based on the total solid content in the composition.

The composition may contain a polymerizable monomer different from the liquid crystal compound. Examples of the polymerizable monomer include a radically polymerizable compound and a cationically polymerizable compound, and a polyfunctional radically polymerizable monomer is preferable. Examples of the polymerizable monomer include the polymerizable monomers described in paragraphs 0018 to 0020 in JP-A-2002-296423.
The polymerizable monomer is preferably a non-liquid crystal compound (a monomer that does not exhibit liquid crystallinity), and more preferably a non-liquid crystal compound having two or more polymerizable groups.
The content of the polymerizable monomer in the composition is not particularly limited, but is preferably 1 to 50% by mass, more preferably 5 to 30% by mass, based on the total mass of the liquid crystal compound.

The composition may contain a surfactant, an orientation control agent, and the like in addition to the above-mentioned components.

The method of applying the composition on the substrate is not particularly limited, and examples thereof include a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, and a die coating method.
If necessary, after the composition is applied, a treatment of drying the coating film applied on the substrate may be performed. By carrying out the drying treatment, the solvent can be removed from the coating film.

In addition, in order to orient the liquid crystal compound in a predetermined direction in step 2 described later, a substrate whose surface has been subjected to a rubbing treatment may be used as the substrate. Further, as described above, an alignment film subjected to a predetermined rubbing treatment may be arranged on the substrate.

(Step 2)
Step 2 is a step of orienting the liquid crystal compound in the coating film.
The treatment for orienting the liquid crystal compound is not particularly limited, but heat treatment is preferable.
As the heat treatment conditions, the optimum conditions are selected according to the liquid crystal compound used.
Among them, the heating temperature is often 10 to 250 ° C., more often 40 to 150 ° C., and even more often 50 to 130 ° C.
The heating time is often 0.1 to 60 minutes, and more often 0.2 to 5 minutes.
The orientation state of the liquid crystal compound differs depending on the material in the coating film. Examples of the orientation state include homogenius orientation.

(Step 3)
Step 3 is a step of pressing a mold having an uneven structure on the surface against the coating film to transfer the uneven structure of the mold to the coating film. In this step, as shown in FIG. 5, a mold 24 having a concave-convex structure on the surface in which a plurality of convex portions 22 are arranged on the support 20 is prepared, and the mold 24 is formed as shown in FIG. It is pressed against the coating film 18 to transfer the uneven structure of the mold to the coating film 18.

As the mold used in this step, a mold capable of transferring to the shape of the structural birefringence member described above on the coating film is appropriately adopted. For example, in FIG. 5, a convex portion 22 extending in one direction and having a trapezoidal cross section in a cross section orthogonal to the extending direction is arranged on the support 20. Further, the plurality of convex portions 22 are periodically arranged along a direction orthogonal to the extending direction. By adjusting the period of the convex portion 22, the period of the extending portion in the structural birefringent member can be adjusted. Further, the height of the extending portion can be adjusted by adjusting the height of the convex portion 22.
The size of the angle θ2 formed by the side of the convex portion 22 on the support 20 side and the hypotenuse in FIG. 5 is not particularly limited, but is preferably 70 to 90 °, more preferably 80 to 90 °.

When pressing the mold against the coating film, it is preferable to heat the mold and press it. The heating temperature of the mold is not particularly limited, but 90 to 130 ° C. is preferable, and 100 to 120 ° C. is more preferable, from the viewpoint that the transfer to the coating film proceeds more satisfactorily.

(Step 4)
When the liquid crystal compound used has a polymerizable group, it is preferable to carry out step 4 after step 3 in which the coating film to which the uneven structure of the mold is transferred is subjected to a curing treatment.

The method of the curing treatment is not particularly limited, and examples thereof include a photo-curing treatment and a thermosetting treatment. Among them, the light irradiation treatment is preferable, and the ultraviolet irradiation treatment is more preferable.
A light source such as an ultraviolet lamp is used for ultraviolet irradiation.
The irradiation amount of light (for example, ultraviolet rays) is not particularly limited, but generally, it is preferably about ^{100 to 1000 mJ / cm 2.}

The orientation state of the liquid crystal compound is fixed in the extending portion formed by the curing treatment.
For example, when the liquid crystal compound in the coating film is homogenically oriented, the extending portion corresponds to a member formed by fixing the homogenius-oriented liquid crystal compound.

After performing the above procedure, as shown in FIG. 7, when the mold 24 is peeled off, it has the above-mentioned substrate 12 and the structural birefringence member 14 composed of the extending portion 16 arranged on the substrate 12. A retardation film is formed.

<Characteristics of retardation film>
The retardation film exhibits anti-wavelength dispersibility. Inverse wavelength dispersibility means that when the in-plane retardation (Re) value is measured in at least a part of the visible light region, the Re value becomes equal or higher as the measurement wavelength becomes larger. In the present invention, the retardation film exhibits anti-wavelength dispersibility as long as it satisfies the relationship of the following formulas (C) and (D).
Equation (C) Re (450) / Re (550) <1.00
Re (450) represents the in-plane retardation of the retardation film at a wavelength of 450 nm, and Re (550) represents the in-plane retardation of the retardation film at a wavelength of 550 nm.
Among them, Re (450) / Re (550) is preferably 0.97 or less, more preferably 0.92 or less, and even more preferably 0.87 or less. The lower limit is not particularly limited, but is often 0.75 or more, preferably 0.78 or more.

Equation (D) Re (650) / Re (550) ≧ 1.00
Re (650) represents the in-plane retardation of the retardation film at a wavelength of 650 nm.
Among them, Re (650) / Re (550) is preferably 1.00 or more, and more preferably 1.01 or more. The upper limit is not particularly limited, but is preferably 1.25 or less, and more preferably 1.20 or less.

The Nz coefficient of the retardation film is preferably 0.40 to 0.60, more preferably 0.45 to 0.60.

The Re (550) of the retardation film is not particularly limited, but is preferably 110 to 160 nm, more preferably 120 to 150 nm in that it is useful as a λ / 4 plate.
The Rth (550) of the retardation film is not particularly limited, but is preferably -50 to 40 nm, more preferably -40 to 30 nm.

The above-mentioned retardation film can be applied to various uses. For example, the in-plane retardation of the retardation film can be adjusted and used as a so-called λ / 4 plate or λ / 2 plate.
The λ / 4 plate is a plate having a function of converting linearly polarized light having a specific wavelength into circularly polarized light (or converting circularly polarized light into linearly polarized light). More specifically, it is a plate showing an in-plane retardation Re of λ / 4 (or an odd multiple of this) at a predetermined wavelength of λ nm.
The in-plane retardation (Re (550)) of the λ / 4 plate at a wavelength of 550 nm may have an error of about 25 nm centered on the ideal value (137.5 nm), and may be, for example, 110 to 160 nm. It is preferably 120 to 150 nm, and more preferably 120 to 150 nm.
The λ / 2 plate refers to an optically anisotropic film in which the in-plane retardation Re (λ) at a specific wavelength λ nm satisfies Re (λ) ≈λ / 2. This equation may be achieved at any wavelength in the visible light region (eg, 550 nm). Above all, it is preferable that the in-plane retardation Re (550) at a wavelength of 550 nm satisfies the following relationship.
210nm ≤ Re (550) ≤ 300nm

The retardation film may have members other than the substrate and the structural birefringence member.
Examples of other members include the above-mentioned alignment film.

<Polarizer>
The retardation film described above may be used as a polarizing plate in combination with a polarizer. In particular, it may be used as a circularly polarizing plate. The circularly polarizing plate is an optical element that converts unpolarized light into circularly polarized light.

The polarizing element may be any member (linearly polarized light) having a function of converting light into specific linearly polarized light, and an absorption type polarizer can be mainly used.
Examples of the absorption type polarizer include an iodine-based polarizer, a dye-based polarizer using a dichroic dye, and a polyene-based polarizer. The iodine-based polarizer and the dye-based polarizer include a coating type polarizing element and a stretching type polarizing element, both of which can be applied, but they are produced by adsorbing iodine or a dichroic dye on polyvinyl alcohol and stretching the polarizing element. Polarizers are preferred.
The relationship between the absorption axis of the polarizer and the slow axis of the retardation film is not particularly limited, but when the retardation film is a λ / 4 plate, the absorption axis of the polarizer and the slow axis of the retardation film The angle formed is preferably in the range of 45 ± 10 °. That is, the angle formed by the absorption axis of the polarizer and the slow axis of the retardation film is preferably in the range of 35 to 55 °.

<Display device>
The retardation film of the present invention and the circularly polarizing plate are preferably applied to a display device.
Examples of the display device include an organic electroluminescence (EL) display device and a liquid crystal display device, and an organic EL display device is preferable.
That is, the display device of the present invention includes the retardation film or circularly polarizing plate and a display element (for example, an organic EL display element or a liquid crystal display element).

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

The features of the present invention will be described in more detail below with reference to Examples and Comparative Examples. The materials, amounts used, ratios, treatment contents, and treatment procedures shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limited by the specific examples shown below.

(Preparation of photo-oriented polymer A)
In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, 100.0 parts by mass of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 500 parts by mass of methylisobutylketone, and triethylamine 10. .0 parts by mass was charged and mixed at room temperature. Next, 100 parts by mass of deionized water was added dropwise to the reaction vessel from a dropping funnel over 30 minutes, and then the reaction was reacted at 80 ° C. for 6 hours while mixing the reaction solution under reflux. After completion of the reaction, the organic phase was taken out, and the organic phase was washed with a 0.2 mass% ammonium nitrate aqueous solution until the water after washing became neutral. Then, the solvent and water were distilled off from the obtained organic phase under reduced pressure to obtain an epoxy-containing polyorganosiloxane as a viscous transparent liquid.
^{When 1} H-NMR (Nuclear Magnetic Resonance) analysis was performed on this epoxy-containing polyorganosiloxane, a peak based on the oxylanyl group was obtained near chemical shift (δ) = 3.2 ppm according to the theoretical intensity, and during the reaction. It was confirmed that no side reaction of the epoxy group occurred. The weight average molecular weight Mw of this epoxy-containing polyorganosiloxane was 2,200, and the epoxy equivalent was 186 g / mol.
Next, in a 100 mL three-necked flask, 10.5 parts by mass of the epoxy-containing polyorganosiloxane obtained above, an acrylic group-containing carboxylic acid (manufactured by Toa Synthetic Co., Ltd., trade name "Aronix M-5300", acrylic acid ω-carboxy) Polycaprolactone (polymerization degree n≈2)) 0.4 parts by mass, butyl acetate 20 parts by mass, 0.5 parts by mass of cinnamic acid derivative obtained by the method of Synthesis Example 1 of JP2015-0206050, tetrahydrocarbon 0.5 parts by mass of carboxylic acid (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.3 parts by mass of tetrabutylammonium bromide were charged and stirred at 90 ° C. for 12 hours. After completion of the reaction, the mixture was diluted with the same amount (mass) of butyl acetate as the reaction solution and washed with water three times. The operation of concentrating this solution and diluting it with butyl acetate was repeated twice, and finally, a solution containing a polyorganosiloxane (polymer) having a photo-oriented group was obtained. The weight average molecular weight Mw of this polymer was 10,000. This polymer was designated as a photo-oriented polymer A.

<Example 1>
(Preparation of Cellulose Achillate Film 1)
The following components were put into a mixing tank and stirred to prepare a cellulose acylate solution to be used as a core layer cellulose acylate dope.
─────────────────────────────────
Core layer Cellulose acylate dope ─────────────────────────────────
100 parts by mass of cellulose acetate having an acetyl substitution degree of 2.88 12 parts by mass of the polyester compound B described in Examples of JP-A-2015-227955, 2 parts by mass of the following compound F 2 parts by mass of methylene chloride (first solvent) 430 parts by mass of methanol (Second solvent) 64 parts by mass ─────────────────────────────────

Compound F

The following matting solution was added to 90 parts by mass of the above core layer cellulose acylate dope to prepare a cellulose acylate solution to be used as the outer layer cellulose acylate dope.
─────────────────────────────────
Matte solution ─────────────────────────────────
Silica particles with an average particle size of 20 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 2 parts by mass Methylene chloride (first solvent) 76 parts by mass Methanol (second solvent) 11 parts by mass The above core layer cellulose acylate dope 1 part by mass Department ──────────────────────────────────

The core layer cellulose acylate dope and the outer layer cellulose acylate dope are filtered through a filter paper having an average pore size of 34 μm and a sintered metal filter having an average pore size of 10 μm, and then the core layer cellulose acylate dope and outer layers provided on both sides thereof are filtered. Cellulose acylate dope was cast in three layers simultaneously on a drum at 20 ° C. from the casting port using a band casting machine.
Next, the film on the drum was peeled off with the solvent content of about 20% by mass, both ends of the film in the width direction were fixed with tenter clips, and the film was dried while being stretched laterally at a stretching ratio of 1.1 times. ..
Then, the obtained film was conveyed between the rolls of the heat treatment apparatus to be further dried to prepare an optical film having a thickness of 40 μm. The core layer had a thickness of 36 μm, and the outer layers arranged on both sides of the core layer had a thickness of 2 μm. The in-plane retardation of the obtained cellulose acylate film 1 was 0 nm.

(Making a retardation film)
The prepared cellulose acylate film 1 was used as a substrate.
The following composition 1 for forming a photoalignment film was continuously applied to one surface of this substrate with a bar coater. After coating, the obtained film was dried in a heating zone at 120 ° C. for 1 minute to remove the solvent, and a composition layer having a thickness of 0.3 μm was formed. ^{Subsequently, a photoalignment film was formed by irradiating with polarized ultraviolet rays (10 mJ / cm 2} , using an ultrahigh pressure mercury lamp) so that the polarization axis formed an angle of 45 ° in the longitudinal direction.

─────────────────────────────────
Composition for forming a photoalignment film 1
─────────────────────────────────
Photo-Orientation Polymer A 10 parts by mass Nomcoat TAB (manufactured by Nisshin Oillio Co., Ltd.) 1.52 parts by mass Polyfunctional epoxy compound (Epolide GT401, manufactured by Daicel)
12.2 parts by mass Thermal acid generator (Sun Aid SI-60, manufactured by Sanshin Chemical Industry Co., Ltd.)
0.55 parts by mass Butyl acetate 300 parts by mass ――――――――――――――――――――――――――――――――――

Nom Court TAB

Next, the following composition 1 for forming a structural birefringent member was applied onto the photoalignment film with a bar coater to form a coating film. The formed coating film was once heated to 110 ° C. in the heating zone to orient the liquid crystal compound, and then cooled to 75 ° C. to stabilize the orientation of the liquid crystal compound.
Next, a mold having a convex portion as shown in FIG. 5 was prepared. Specifically, as shown in FIG. 5, a direction in which a convex portion having a trapezoidal cross section extending in one direction and having a cross section orthogonal to the extending direction extends on the support at a period of 400 nm. We prepared multiple molds arranged in the direction orthogonal to. The height of the convex portion was adjusted so that the ratio of the height of the extending portion to the period of the extending portion (height of the extending portion / period of the extending portion) became the value in Table 1 described later. Further, the size of the angle θ (θ2 in FIG. 5) formed by the side of the convex portion on the substrate side and the hypotenuse was 80 °.
Next, the prepared mold was kept at 75 ° C., the mold was pressed against the coating film, and the groove shape of the mold was transferred. The mold was pressed against the composition layer so that the extending direction of the convex portion in the mold and the orientation direction of the liquid crystal compound coincided with each other.
Next, with the mold pressed, the coating film is irradiated with ultraviolet rays (500 mJ / cm ² , using an ultra-high pressure mercury lamp) to fix the orientation of the liquid crystal compound and peel it off from the mold to form a structure. A birefringent member was formed to produce a retardation film.
The structural birefringence member in the obtained retardation film was composed of an extending portion formed by aligning and fixing the liquid crystal compound. The extending portion is a member extending in one direction, the cross-sectional shape in the direction orthogonal to the extending direction is trapezoidal, the length (maximum width) of the base is 220 nm, and the base and the hypotenuse are The angle formed by (θ1 in FIG. 2) was 80 °. Further, the direction of the slow phase axis (in-plane slow phase axis) of the extending portion was parallel to the extending direction of the extending portion.

―――――――――――――――――――――――――――――――――
Composition for forming a structural birefringent member 1
―――――――――――――――――――――――――――――――――
-The following liquid crystal compound L-3 42.00 parts by mass-The following liquid crystal compound L-4 42.00 parts by mass-The following polymerizable compound A-1 16.00 parts by mass-The following polymerization initiator S-1 (oxime type) 0 .50 parts by mass, leveling agent (Compound G-1 below) 0.20 parts by mass, High Solve MTEM (manufactured by Toho Chemical Industry Co., Ltd.) 2.00 parts by mass, NK ester A-200 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) 1. 00 parts by mass, methyl ethyl ketone 424.8 parts by mass ――――――――――――――――――――――――――――――――――
The group adjacent to the acryloyloxy group of the following liquid crystal compounds L-3 and L-4 represents a propylene group (a group in which a methyl group is replaced with an ethylene group), and the following liquid crystal compounds L-3 and L-4 are: Represents a mixture of positional isomers with different methyl group positions.

Liquid crystal compound L-3

Liquid crystal compound L-4

Polymerizable compound A-1

Polymerization Initiator S-1

Compound G-1 (The numerical value in each repeating unit represents the content (mass%) with respect to all repeating units, the content of the repeating unit on the left side is 32.5% by mass, and the content of the repeating unit on the right side is 67. It was 5% by mass.)

<Examples 2 to 5>
A retardation film was produced according to the same procedure as in Example 1 except that the shape of the mold was changed so that the structural birefringent member having the characteristics shown in Table 1 described later could be obtained.
In any of Examples 1 to 5, the extending portion was a member formed by aligning and fixing a liquid crystal compound exhibiting reverse wavelength dispersibility.

<Comparative example 1>
Instead of the structural birefringence member forming composition 1, the structural birefringent member forming composition 2 described later is used, and the shape of the mold and the like are adjusted so that the structural birefringent member having the characteristics shown in Table 1 described later can be obtained. A retardation film was produced according to the same procedure as in Example 1 except for the modification.

―――――――――――――――――――――――――――――――――
Composition for forming a structural birefringent member 2
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・ The following rod-shaped liquid crystal compound (A) 20 parts by mass ・ The following rod-shaped liquid crystal compound (B) 80 parts by mass ・ Photopolymerization initiator (Irgacure-907, manufactured by Ciba Japan) 3 parts by mass ・ Sensitizer (Kayacure DETX, Japan) (Manufactured by Kayaku Co., Ltd.) 1 part by mass, 0.3 parts by mass of the following fluoropolymer (FP4), 193 parts by mass of methyl ethyl ketone, 50 parts by mass of cyclohexanone ―――――――――――――――― ―――――――――――――――――

Rod-shaped liquid crystal compound (A)

In Table 1, in the "wavelength dispersion" column, the case where a liquid crystal compound having a reverse wavelength dispersion is used is referred to as "reverse wavelength dispersion", and the case where a liquid crystal compound exhibiting a forward wavelength dispersion is used is referred to as "forward wavelength dispersion".
In Table 1, the "pitch" column represents the period (pitch) in which the extending portion is arranged.
In Table 1, the "ratio" column represents the ratio of the height of the extending portion to the period in which the extending portion is arranged.
In Table 1, the “Re (450)” column represents the in-plane retardation (nm) of the obtained retardation film at a wavelength of 450 nm.
In Table 1, the “Re (450) / Re (550)” column represents the ratio of the in-plane retardation at a wavelength of 450 nm to the in-plane retardation of the obtained retardation film at a wavelength of 550 nm.
In Table 1, the “Re (650) / Re (550)” column represents the ratio of the in-plane retardation at a wavelength of 650 nm to the in-plane retardation of the obtained retardation film at a wavelength of 550 nm.

As shown in Table 1, it was confirmed that the retardation film of the present invention exerts a predetermined effect.

10 Phase difference film 12 Substrate 14 Structural birefringence member 16 Extended part 18 Coating film 20 Support 22 Convex part 24 Mold

Claims (5)

It has a substrate and a structural birefringent member arranged on the substrate.
The structural birefringent member is a member in which a plurality of extending portions extending in one direction are periodically arranged in a direction orthogonal to the one direction.
The extending portion is a member formed by orienting and fixing the liquid crystal compound.
The direction of the slow axis of the extending portion is substantially parallel to the one direction.
A retardation film in which the structural birefringent member satisfies the following requirement 1 or requirement 2.
Requirement 1: The liquid crystal compound is a liquid crystal compound exhibiting reverse wavelength dispersibility.
Requirement 2: The period in which the extending portion is arranged is 700 nm or less. The retardation film according to claim 1, wherein the ratio of the height of the extending portion to the period in which the extending portion is arranged is 1.00 to 2.00. The retardation film according to claim 1 or 2, wherein the extending portion is a member formed by using a composition containing a liquid crystal compound having two or more polymerizable groups and exhibiting anti-wavelength dispersibility. The retardation film according to any one of claims 1 to 3 and
A circularly polarizing plate having a polarizer. A display device having the retardation film according to any one of claims 1 to 3 or the circularly polarizing plate according to claim 4.

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