Method for manufacturing an optically anisotropic layer

Abstract

The present application provides a simple manufacturing method of an optical anisotropic layer in which the alignment state of liquid crystal compounds is fixed and which has a plurality of regions in which the alignment state of the liquid crystal compounds is different in the thickness direction. The manufacturing method of the optical anisotropic layer of the present application includes: Step 1 in which a composition layer is formed, the composition layer containing liquid crystal compounds having a polymerizable group; Step 2 in which a heating treatment is performed on the composition layer to align the liquid crystal compounds in the composition layer; Step 3 in which, after Step 2, a light irradiation is performed on the composition layer at a temperature higher than the temperature at which the light irradiation is performed; Step 4 in which, after Step 3, a heating treatment is performed on the composition layer at a temperature higher than the temperature at which the light irradiation is performed; and Step 5 in which, after Step 4, a curing treatment is performed on the composition layer to form an optical anisotropic layer having a plurality of regions in which the alignment state of the liquid crystal compounds is different in the thickness direction. 2 The following light irradiation is performed for 50 seconds or less; Step 4 in which, after Step 3, a heating treatment is performed on the composition layer at a temperature higher than the temperature at which the light irradiation is performed; and Step 5 in which, after Step 4, a curing treatment is performed on the composition layer to form an optical anisotropic layer having a plurality of regions in which the alignment state of the liquid crystal compounds is different in the thickness direction.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for manufacturing an optically anisotropic layer. BACKGROUND

[0002] An optical compensation film for liquid crystal display devices, an antireflection film for display devices, and the like are used for various purposes. An optically anisotropic layer having a refractive index anisotropy is used for the optical compensation film for liquid crystal display devices, the antireflection film for display devices, and the like.

[0003] As the optically anisotropic layer, as described in Patent Literature 1, a laminated optically anisotropic layer composed of a plurality of layers is disclosed.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent No. 5960743 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] Conventionally, in manufacturing the optically anisotropic layer as described in Patent Literature 1, the laminated optically anisotropic layer is formed by performing coating for each layer, and thus there are problems of low productivity and increased cost.

[0009] Further, at the time of repeating the coating, there are cases where repulsion of the coating liquid occurs and the desired optically anisotropic layer cannot be formed.

[0010] In view of the above, an object of the present application is to provide a simple method for manufacturing an optically anisotropic layer in which the orientation state of a liquid crystal compound is fixed and which has a plurality of regions in which the orientation state of the liquid crystal compound is different in the thickness direction.

[0011] MEANS FOR SOLVING THE PROBLEMS

[0012] As a result of intensive studies by the present inventors and the like on the problems of the prior art, it has been found that the above problems can be solved by the following structure.

[0013] (1) A method for manufacturing an optically anisotropic layer, comprising:

[0014] Step 1 in which a composition layer containing a liquid crystal compound having a polymerizable group is formed;

[0015] Step 2 in which the composition layer is subjected to a heating treatment to orient the liquid crystal compound in the composition layer;

[0016] Step 3 which is performed after Step 2, in which the composition layer is subjected to 300 mJ / cm 2The following light irradiation is performed for 50 seconds or less;

[0017] Step 4, which is a step of performing a heat treatment on the composition layer at a higher temperature than the light irradiation after Step 3; and

[0018] Step 5, which is a step of performing a curing treatment on the composition layer after Step 4 to form an optically anisotropic layer having a plurality of regions with different alignment states of the liquid crystal compound in the thickness direction.

[0019] (2) The method for manufacturing an optically anisotropic layer according to (1), wherein the composition layer contains a photosensitive material selected from the group consisting of a photopolymerization initiator and a photosensitizer,

[0020] The molar absorption coefficient of the photosensitive material at the wavelength of the light irradiation in Step 3 is 5000 L / (mol·cm) or less.

[0021] (3) The method for manufacturing an optically anisotropic layer according to (1) or (2), wherein the composition layer contains a chiral agent,

[0022] The chiral agent contains a photosensitive chiral agent whose helical twisting power changes by light irradiation.

[0023] (4) The method for manufacturing an optically anisotropic layer according to (3), wherein the total content of the chiral agent is 5.0% by mass or less with respect to the total mass of the liquid crystal compound.

[0024] (5) The method for manufacturing an optically anisotropic layer according to (3), wherein the total content of the chiral agent is more than 5.0% by mass with respect to the total mass of the liquid crystal compound.

[0025] (6) The method for manufacturing an optically anisotropic layer according to (1) or (2), wherein the composition layer contains a photosensitive compound whose polarity changes by light irradiation.

[0026] (7) The method for manufacturing an optically anisotropic layer according to (6), wherein the photosensitive compound is a photosensitive compound that is hydrophilized by light irradiation.

[0027] (8) The method for manufacturing an optically anisotropic layer according to (1) or (2), wherein the temperature of the heat treatment in Step 4 is a temperature of 120°C or higher.

[0028] Effects of the Invention

[0029] According to the present application, a simple method for manufacturing an optically anisotropic layer having a plurality of regions with different alignment states of a liquid crystal compound in the thickness direction can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a sectional view of a composition layer for explaining an example of Step 1A of the first embodiment of the method for manufacturing an optically anisotropic layer of the present application.

[0031] Figure 2 is a sectional view of a composition layer for explaining an example of Step 3A of the first embodiment of the method for manufacturing an optically anisotropic layer of the present application.

[0032] Figure 3 is a sectional view of a composition layer for explaining an example at the time of Step 4A of the first embodiment of the method for manufacturing an optically anisotropic layer of the present application.

[0033] Figure 4 is a schematic view of a graph plotting the relationship between the helical twisting power (HTP: Helical Twisting Power) (pm -1 ) x concentration (mass %) and the light irradiation amount (mJ / cm 2 ) with respect to each of chiral agent A and chiral agent B.

[0034] Figure 5 is a schematic view of a graph plotting the relationship between the weighted average helical twisting power (pm -1 ) and the light irradiation amount (mJ / cm 2 ) in a system in which chiral agent A and chiral agent B are used together.

[0035] Figure 6 is a sectional view of a composition layer for explaining another example of Step 1A of the first embodiment of the method for manufacturing an optically anisotropic layer of the present application.

[0036] Figure 7 is a sectional view of a composition layer for explaining another example at the time of Step 4A of the first embodiment of the method for manufacturing an optically anisotropic layer of the present application.

[0037] Figure 8 is a sectional view of a composition layer for explaining an example of Step 3B of the second embodiment of the method for manufacturing an optically anisotropic layer of the present application.

[0038] Figure 9 is a sectional view of a composition layer for explaining an example of Step 4B of the second embodiment of the method for manufacturing an optically anisotropic layer of the present application.

[0039] Figure 10 is a schematic view of a graph plotting the relationship between the helical twisting power (pm -1 ) and the light irradiation amount (mJ / cm 2 ) with respect to chiral agent A.

[0040] Figure 11 FIG. 3C is a cross-sectional view of a composition layer for explaining an example of Step 3C of the manufacturing method of the optically anisotropic layer according to the third embodiment of the present application.

[0041] Figure 12 FIG. 4C is a cross-sectional view of a composition layer for explaining an example of Step 4C of the manufacturing method of the optically anisotropic layer according to the third embodiment of the present application.

[0042] Figure 13 FIG. 3D is a cross-sectional view of a composition layer for explaining an example of Step 3D of the manufacturing method of the optically anisotropic layer according to the fourth embodiment of the present application.

[0043] Figure 14 FIG. 4D is a cross-sectional view of a composition layer for explaining an example of Step 4D of the manufacturing method of the optically anisotropic layer according to the fourth embodiment of the present application.

[0044] Figure 15 FIG. 5 is a cross-sectional view showing an embodiment of the laminate according to the present application.

[0045] Figure 16 FIG. 6 is a cross-sectional view showing an embodiment of the optically anisotropic layer with a polarizer according to the present application. DETAILED DESCRIPTION

[0046] Hereinafter, the present application will be described in detail. In the present specification, a numerical range represented by "to" indicates a range including the numerical values recited before and after "to" as lower limit values and upper limit values. First, the terms used in the present specification will be described.

[0047] Unless otherwise specifically noted, the slow axis is defined at 550 nm.

[0048] In the present application, Re(λ) and Rth(λ) represent the in-plane retardation and the thickness direction retardation at a wavelength λ, respectively. Unless otherwise specifically noted, the wavelength λ is set to 550 nm.

[0049] In the present application, Re(λ) and Rth(λ) are values obtained by measurement at a wavelength λ using AxoScan (manufactured by Axometrics, Inc.). By inputting the average refractive index ((nx+ny+nz) / 3) and the film thickness (d (μm)) in AxoScan, Re(λ) and Rth(λ) are calculated as follows.

[0050] Slow axis direction (°)

[0051] Re(λ) = R0(λ)

[0052] Rth(λ) = ((nx+ny) / 2-nz) x d.

[0053] In addition, R0(λ) shows a value calculated by AxoScan, but indicates Re(λ).

[0054] In the present specification, with respect to the refractive indexes nx, ny, and nz, an Abbe refractometer (NAR-4T, manufactured by ATAGO CO., LTD.) was used, and a sodium lamp (λ = 589 nm) was used as a light source for measurement. Also, in the case of measuring wavelength dependency, a multi-wavelength Abbe refractometer DR-M2 (manufactured by ATAGO CO., LTD.) can be used in combination with an interference filter for measurement.

[0055] Also, values of the Handbook of Polymers (JOHN WILEY & SONS, INC) and catalogs of various optical films can be used. Values of average refractive indexes of main optical films are exemplified below: cellulose acylate (1.48), cyclic olefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).

[0056] In the present specification, "light" means an active light ray or a radiation ray, for example, a bright line spectrum of a mercury lamp, far ultraviolet rays typified by an excimer laser, extreme ultraviolet (EUV light), X-rays, ultraviolet rays, and electron beams (EB), and the like. Among them, ultraviolet rays are preferable.

[0057] In the present specification, "visible light" refers to light of 380 to 780 nm. Also, in the present specification, in the case where a measurement wavelength is not particularly described, the measurement wavelength is 550 nm.

[0058] In the present specification, in the case where a liquid crystal compound is twisted and oriented in the optically anisotropic layer, a twist angle thereof is preferably more than 0° and less than 360°. In addition, a cholesteric liquid crystal phase described later is a phase having a periodic structure in which a liquid crystal compound is oriented in a spiral shape, and a twist angle is 360° or more.

[0059] As a feature point of the method for producing the optically anisotropic layer of the present application, a point that a prescribed process is implemented can be mentioned.

[0060] As described in detail later, in the present application, first, the liquid crystal compound in the composition layer is oriented. The oxygen concentration is low in a part of the region of the substrate side of the formed composition layer, and the oxygen concentration is high in the other region of the surface side of the side opposite to the substrate side. Therefore, if the composition layer is subjected to light irradiation under a prescribed condition, polymerization of the liquid crystal compound is difficult in the region where the oxygen concentration is high and is easy in the region where the oxygen concentration is low. In the region where the polymerization of the liquid crystal compound is easy, the orientation state of the liquid crystal compound is fixed. Also, at the time of the heating treatment performed after the light irradiation, the orientation state of the liquid crystal compound does not change in the region where the polymerization of the liquid crystal compound is performed, but the orientation state changes in the region where the polymerization of the liquid crystal compound is difficult, and the changed orientation state is fixed at the time of the curing treatment. As a result, the optically anisotropic layer having a plurality of regions different in the orientation state of the liquid crystal compound in the thickness direction can be produced.

[0061] The method for producing the optically anisotropic layer of the present application includes:

[0062] Process 1 in which a composition layer is formed, the composition layer containing a liquid crystal compound having a polymerizable group;

[0063] Process 2 in which a heating treatment is performed on the composition layer to orient the liquid crystal compound in the composition layer;

[0064] Process 3 which is performed after Process 2, in which a light irradiation is performed on the composition layer at an oxygen concentration of 1 vol% or more at 300 mJ / cm 2 The light irradiation is performed for 50 seconds or less;

[0065] Process 4 which is performed after Process 3, in which a heating treatment is performed on the composition layer at a higher temperature than at the time of the light irradiation; and

[0066] Process 5 which is performed after Process 4, in which a curing treatment is performed on the composition layer to form the optically anisotropic layer having a plurality of regions different in the orientation state of the liquid crystal compound in the thickness direction.

[0067] In addition, by performing the above-mentioned Process 5, the orientation state of the liquid crystal compound is fixed.

[0068] As the manner of having regions different in the orientation state of the liquid crystal compound, as described later, for example, there can be mentioned a manner in which the helical pitch of the cholesteric liquid crystal phase of the plurality of regions is different from each other, a manner in which the tilt angle of the orientation direction of the liquid crystal compound of the plurality of regions with respect to the surface of the layer is different, and a manner in which one of the two regions is a region in which the state of the liquid crystal compound showing the isotropic phase is fixed and the other region is a region in which the orientation state of the oriented liquid crystal compound is fixed.

[0069] Hereinafter, each preferred mode of the method for producing the optically anisotropic layer of the present application will be described in detail.

[0070] <<First Embodiment>>

[0071] The first embodiment of the method for producing the optically anisotropic layer of the present application includes the following steps 1A to 5A. In the first embodiment, as will be described later, an optically anisotropic layer having a region in which the orientation state of a liquid crystal compound twisted along a helical axis extending in the thickness direction is fixed is formed.

[0072] Step 1A: This is a step in which a composition layer is formed, the composition layer containing at least a chiral agent containing a photosensitive chiral agent whose helical twisting power changes by light irradiation and a liquid crystal compound having a polymerizable group

[0073] Step 2A: This is a step in which a heat treatment is performed on the composition layer to orient the liquid crystal compound in the composition layer

[0074] Step 3A: This is a step in which, after Step 2A, a heat treatment is performed on the composition layer at a temperature of 300 mJ / cm 2 the following light irradiation is performed for 50 seconds or less

[0075] Step 4A: This is a step in which, after Step 3A, a heat treatment is performed on the composition layer at a higher temperature than at the time of light irradiation

[0076] Step 5A: This is a step in which, after Step 4A, a curing treatment is performed on the composition layer to form an optically anisotropic layer having a plurality of regions in which the orientation state of the liquid crystal compound differs in the thickness direction. As will be described later, in the first embodiment, in order to produce an optically anisotropic layer having the above-described characteristics, the total content of the chiral agent (the total content of all chiral agents) in the composition layer is preferably 5.0% by mass or less with respect to the total mass of the liquid crystal compound.

[0077] Hereinafter, the steps of each of the above steps will be described in detail.

[0078] <<Step 1A>>

[0079] Step 1A is a step in which a composition layer is formed, the composition layer containing at least a chiral agent containing a photosensitive chiral agent whose helical twisting power changes by light irradiation and a liquid crystal compound having a polymerizable group. By performing this step, a composition layer on which the light irradiation treatment described later is performed can be formed.

[0080] Hereinafter, first, the materials used in this step will be described in detail, and then the steps of the step will be described in detail.

[0081] (chiral reagent)

[0082] The composition layer of the process 1A contains a chiral reagent containing at least a photosensitive chiral reagent whose helical twisting power changes by light irradiation. First, the photosensitive chiral reagent whose helical twisting power changes by light irradiation is described in detail.

[0083] In addition, the helical twisting power (HTP) of the chiral reagent is a factor indicating the helical orientation ability represented by the following formula (A).

[0084] Formula (A) HTP = 1 / (length of helical pitch (unit: pm) x concentration of chiral reagent with respect to liquid crystal compound (mass%)) [pm -1 ]

[0085] The length of the helical pitch refers to the length of the pitch P (= period of helix) of the helical structure of the cholesteric liquid crystal phase, and can be measured using the method described in page 196 of "Liquid Crystal Handbook" (published by MARUZEN GROUP).

[0086] The photosensitive chiral reagent whose helical twisting power changes by light irradiation (hereinafter, also simply referred to as "chiral reagent A") can be liquid crystalline or non-liquid crystalline. The chiral reagent A is often composed of an asymmetric carbon atom. In addition, the chiral reagent A can be an axial asymmetric compound or a surface asymmetric compound not containing an asymmetric carbon atom.

[0087] The chiral reagent A can be a chiral reagent whose helical twisting power increases by light irradiation, or a chiral reagent whose helical twisting power decreases. Among them, a chiral reagent whose helical twisting power decreases by light irradiation is preferred.

[0088] In addition, in the present specification, "increase and decrease in helical twisting power" indicates the increase and decrease when the helical direction of the chiral reagent A at the initial (before light irradiation) is set to "positive". Therefore, in the case where the helical twisting power continuously decreases by light irradiation and exceeds 0, and the helical direction becomes "negative" (i.e., in the case of a helix whose helical direction is opposite to the helical direction at the initial (before light irradiation)), it also corresponds to a "chiral reagent whose helical twisting power decreases".

[0089] As the chiral reagent A, a so-called photo-reactive chiral reagent can be given. The photo-reactive chiral reagent is a compound having a chiral site and a photo-reactive site whose structure changes by light irradiation, and, for example, the twisting power of the liquid crystal compound is significantly changed depending on the amount of irradiation.

[0090] As an example of a photoactive site which undergoes a structural change by light irradiation, a photochromic compound (Uchida, S., Irie, M., Kagaku Kogyo, vol. 64, 640p, 1999, Uchida, S., Irie, M., Shikizai, vol. 28(9), 15p, 1999) and the like can be given. Further, the above-mentioned structural change indicates decomposition, addition reaction, isomerization, racemization, [2+2] photocyclization, dimerization reaction and the like which are produced by irradiating light to the photoactive site, and the above-mentioned structural change can be irreversible. Further, as a chiral site, for example, an asymmetric carbon equivalent to that described in Nomura, H., Zairyo Zokan, No. 22, Chemistry of Liquid Crystals, 73p: 1994 and the like can be given.

[0091] As the chiral reagent A, for example, there can be mentioned the optically reactive chiral reagent described in paragraphs 0044 to 0047 of Japanese Patent Application Publication No. 2001-159709, the optically active compound described in paragraphs 0019 to 0043 of Japanese Patent Application Publication No. 2002-179669, the optically active compound described in paragraphs 0020 to 0044 of Japanese Patent Application Publication No. 2002-179633, the optically active compound described in paragraphs 0016 to 0040 of Japanese Patent Application Publication No. 2002-179670, the optically active compound described in paragraphs 0017 to 0050 of Japanese Patent Application Publication No. 2002-179668, the optically active compound described in paragraphs 0018 to 0044 of Japanese Patent Application Publication No. 2002-180051, the optically active isosorbide derivative described in paragraphs 0016 to 0055 of Japanese Patent Application Publication No. 2002-338575, the optically reactive optically active compound described in paragraphs 0023 to 0032 of Japanese Patent Application Publication No. 2002-080478, the optically reactive chiral reagent described in paragraphs 0019 to 0029 of Japanese Patent Application Publication No. 2002-080851, the optically active compound described in paragraphs 0022 to 0049 of Japanese Patent Application Publication No. 2002-179681, the optically active compound described in paragraphs 0015 to 0044 of Japanese Patent Application Publication No. 2002-302487, the optically active polyester described in paragraphs 0015 to 0050 of Japanese Patent Application Publication No. 2002-338668, the binaphthyl derivative described in paragraphs 0019 to 0041 of Japanese Patent Application Publication No. 2003-055315, the optically active Fulgide compound described in paragraphs 0008 to 0043 of Japanese Patent Application Publication No. 2003-073381, the optically active isosorbide derivative described in paragraphs 0015 to 0057 of Japanese Patent Application Publication No. 2003-306490, the optically active isosorbide derivative described in paragraphs 0015 to 0041 of Japanese Patent Application Publication No. 2003-306491, the optically active isosorbide derivative described in paragraphs 0015 to 0049 of Japanese Patent Application Publication No. 2003-313187, the optically active isomannide derivative described in paragraphs 0015 to 0057 of Japanese Patent Application Publication No. 2003-313188, the optically active isosorbide derivative described in paragraphs 0015 to 0049 of Japanese Patent Application Publication No. 2003-313189, the optically active polyester / amide described in paragraphs 0015 to 0052 of Japanese Patent Application Publication No. 2003-313292, the optically active compound described in paragraphs 0012 to 0053 of WO 2018 / 194157, and the optically active compound described in paragraphs 0020 to 0049 of Japanese Patent Application Publication No. 2002-179682, and the like.

[0092] As the chiral reagent A, a compound having at least a photoisomerization site is preferable, and a compound having a double bond capable of photoisomerization is more preferable. As the photoisomerization site having a double bond capable of photoisomerization, from the viewpoints of easy occurrence of photoisomerization and large difference in helical twisting power before and after light irradiation, a cinnamoyl site, a chalcone site, an azobenzene site, or a stilbene site is preferable, and from the viewpoint of small absorption of visible light, a cinnamoyl site, a chalcone site, or a stilbene site is more preferable. In addition, the photoisomerization site corresponds to the above-mentioned photo-reactive site whose structure is changed by light irradiation.

[0093] Further, from the viewpoints of high helical twisting power at the initial (before light irradiation) and more excellent change amount of helical twisting power based on light irradiation, the chiral reagent A preferably has a trans double bond capable of photoisomerization.

[0094] Further, from the viewpoints of low helical twisting power at the initial (before light irradiation) and more excellent change amount of helical twisting power based on light irradiation, the chiral reagent A preferably has a cis double bond capable of photoisomerization.

[0095] The chiral reagent A preferably has any one of a binaphthalene partial structure, an isosorbide partial structure (a partial structure derived from isosorbide), and an isomannide partial structure (a partial structure derived from isomannide). In addition, the binaphthalene partial structure, the isosorbide partial structure, and the isomannide partial structure respectively refer to the following structures.

[0096] The part in which the solid line and the dotted line are parallel in the binaphthalene partial structure represents a single bond or a double bond. In addition, in the structures shown below, * represents a bonding position.

[0097] [Chemical Formula 1]

[0098]

[0099] The chiral reagent A can have a polymerizable group. The kind of the polymerizable group is not particularly limited, and a functional group capable of addition polymerization is preferable, and a polymerizable ethylenically unsaturated group or a cyclic polymerizable group is more preferable, and a (meth)acryloyl group, a vinyl group, a styryl group, or an allyl group is further preferable.

[0100] As the chiral reagent A, a compound represented by Formula (C) is preferable.

[0101] Formula (C) R-L-R

[0102] R respectively independently represents a group having at least one site selected from the group consisting of a cinnamoyl site, a chalcone site, an azobenzene site, and a stilbene site.

[0103] L represents a divalent linking group formed by removing two hydrogen atoms from the structure represented by formula (D) (a divalent linking group formed by removing two hydrogen atoms from the above-mentioned binaphthyl moiety structure), a divalent linking group represented by formula (E) (a divalent linking group composed of the above-mentioned isosorbide moiety structure), or a divalent linking group represented by formula (F) (a divalent linking group composed of the above-mentioned isomannide moiety structure).

[0104] In formula (E) and formula (F), * represents a bonding position.

[0105] [Chemical Formula 2]

[0106]

[0107] In the process 1A, at least the above-mentioned chiral reagent A can be used. The process 1A can be a manner using two or more kinds of chiral reagent A, or can be a manner using at least one chiral reagent A and at least one chiral reagent (hereinafter, also simply referred to as "chiral reagent B") which does not change the helical twisting power by light irradiation.

[0108] The chiral reagent B can be liquid crystalline or non-liquid crystalline. The chiral reagent B is often composed of an asymmetric carbon atom. In addition, the chiral reagent B can be an axial asymmetric compound or a surface asymmetric compound which does not contain an asymmetric carbon atom.

[0109] The chiral reagent B can have a polymerizable group. As the kind of the polymerizable group, the polymerizable group that the chiral reagent A can have can be mentioned.

[0110] As the chiral reagent B, a publicly known chiral reagent can be used.

[0111] The chiral reagent B is preferably a chiral reagent which twists a helix in the opposite direction to the above-mentioned chiral reagent A. That is, for example, in the case where a helix twisted by the chiral reagent A is right, a helix twisted by the chiral reagent B is left.

[0112] The molar absorption coefficient of the chiral reagent A and the chiral reagent B is not particularly limited, but the molar absorption coefficient at the wavelength (for example, 365 nm) of the light irradiated in the process 3A described later is preferably 100 to 100,000 L / (mol·cm), and more preferably 500 to 50,000 L / (mol·cm).

[0113] The content of each of the chiral agent A and the chiral agent B in the composition layer can be appropriately set depending on the characteristics (e.g., retardation or wavelength dispersion) of the optically anisotropic layer to be formed. In addition, the twist angle of the liquid crystal compound in the optically anisotropic layer largely depends on the kinds of the chiral agent A and the chiral agent B and their added concentrations, and thus by adjusting these, the alignment state of the liquid crystal compound can be controlled.

[0114] In the first embodiment, the total content of the chiral agent (total content of all chiral agents) in the composition layer is not particularly limited, but from the viewpoint of easily controlling the alignment state of the liquid crystal compound, it is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, and further preferably 2.0% by mass or less, with respect to the total mass of the liquid crystal compound. The lower limit is not particularly limited, but it is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and further preferably 0.05% by mass or more.

[0115] The content of the chiral agent A in the chiral agent is not particularly limited, but from the viewpoint of easily controlling the alignment state of the liquid crystal compound, it is preferably 5 to 95% by mass, and more preferably 10 to 90% by mass, with respect to the total mass of the chiral agent.

[0116] (Liquid crystal compound)

[0117] The composition layer of the step 1A contains a liquid crystal compound having a polymerizable group.

[0118] The kind of the liquid crystal compound is not particularly limited. In general, the liquid crystal compound can be classified into a rod-like type (rod-like liquid crystal compound) and a disc-like type (discotic liquid crystal compound) depending on its shape. Also, the liquid crystal compound can be classified into a low molecular type and a high molecular type. The high molecular generally refers to a compound having a polymerization degree of 100 or more (Kobunshi Buturi / Kanzen Doryoku Gaku, Shigeo Doki, 2 pages, Gakugei Tosho, 1992). In the present application, any liquid crystal compound can be used, but a rod-like liquid crystal compound or a discotic liquid crystal compound is preferably used, and a rod-like liquid crystal compound is more preferably used. Two or more kinds of rod-like liquid crystal compounds, two or more kinds of discotic liquid crystal compounds, or a mixture of a rod-like liquid crystal compound and a discotic liquid crystal compound can be used.

[0119] In addition, as the rod-like liquid crystal compound, for example, a rod-like liquid crystal compound described in claim 1 of Japanese Laid-Open Patent Publication No. 11-513019 or paragraphs 0026 to 0098 of Japanese Laid-Open Patent Publication No. 2005-289980 can be preferably used.

[0120] As the discotic liquid crystal compound, for example, the discotic liquid crystal compound described in paragraphs 0020 to 0067 of Japanese Patent Application Publication No. 2007-108732 or paragraphs 0013 to 0108 of Japanese Patent Application Publication No. 2010-244038 can be preferably used.

[0121] The type of the polymerizable group possessed by the liquid crystal compound is not particularly limited, and is preferably a functional group capable of undergoing an addition polymerization reaction, more preferably a polymerizable ethylenically unsaturated group or a cyclic polymerizable group, and further preferably a (meth)acryloyl group, a vinyl group, a styryl group, or an allyl group.

[0122] In addition, the optically anisotropic layer produced in the present application is a layer formed by fixing a liquid crystal compound having a polymerizable group (a rod-like liquid crystal compound or a discotic liquid crystal compound having a polymerizable group) by polymerization or the like, and does not need to exhibit liquid crystallinity after being formed into a layer.

[0123] The content of the liquid crystal compound in the composition layer is not particularly limited, but from the viewpoint of easily controlling the alignment state of the liquid crystal compound, it is preferably 60% by mass or more, and more preferably 70% by mass or more, relative to the total mass of the composition layer. The upper limit is not particularly limited, but is preferably 99% by mass or less, and more preferably 97% by mass or less.

[0124] (Other Components)

[0125] The composition layer can contain other components in addition to the above-mentioned chiral agent and the liquid crystal compound.

[0126] For example, the composition layer can contain a polymerization initiator. In the case where the composition layer contains a polymerization initiator, the polymerization of the liquid crystal compound having a polymerizable group is more effectively performed.

[0127] As the polymerization initiator, a known polymerization initiator can be mentioned, and a photopolymerization initiator and a thermal polymerization initiator can be mentioned, and a photopolymerization initiator is preferred. In particular, a polymerization initiator that is photosensitive to light irradiated in the following process 5A is preferred.

[0128] The molar absorption coefficient of the polymerization initiator at the wavelength of the light irradiated in the process 3A is preferably 0.1 times or less of the molar absorption coefficient at the wavelength of the light irradiated in the process 5A.

[0129] Further, from the viewpoint of easily forming a prescribed optically anisotropic layer, the molar absorption coefficient of the polymerization initiator at the wavelength of the light irradiation in Step 3A is preferably 5000 L / (mol-cm) or less, more preferably 4000 L / (mol-cm) or less, and further preferably 3000 L / (mol-cm) or less. There is no particular limitation on the lower limit, and it is preferably 0 L / (mol-cm), but cases of 30 L / (mol-cm) or more are common.

[0130] The content of the polymerization initiator in the composition layer is not particularly limited, but is preferably 0.01 to 20% by mass, and more preferably 0.5 to 10% by mass, relative to the total mass of the composition layer.

[0131] The composition layer can contain a photosensitizer.

[0132] The kind of the photosensitizer is not particularly limited, and known photosensitizers can be given.

[0133] Further, from the viewpoint of easily forming a prescribed optically anisotropic layer, the molar absorption coefficient of the photosensitizer at the wavelength of the light irradiation in Step 3A is preferably 5000 L / (mol-cm) or less, more preferably 4800 L / (mol-cm) or less, and further preferably 4500 L / (mol-cm) or less. There is no particular limitation on the lower limit, and it is preferably 0 L / (mol-cm), but cases of 30 L / (mol-cm) or more are common.

[0134] The content of the photosensitizer in the composition layer is not particularly limited, but is preferably 0.01 to 20% by mass, and more preferably 0.5 to 10% by mass, relative to the total mass of the composition layer.

[0135] The composition layer can contain a polymerizable monomer different from the liquid crystal compound having a polymerizable group. As the polymerizable monomer, radical polymerizable compounds and cationic polymerizable compounds can be given, and a multifunctional radical polymerizable monomer is preferable. As the polymerizable monomer, for example, the polymerizable monomers described in paragraphs 0018 to 0020 of Japanese Patent Application Publication No. 2002-296423 can be given.

[0136] The content of the polymerizable monomer in the composition layer is not particularly limited, but is preferably 1 to 50% by mass, and more preferably 5 to 30% by mass, relative to the total mass of the liquid crystal compound.

[0137] The composition layer can contain a surfactant. As the surfactant, a compound known in the art can be mentioned, and a fluorine-based compound is preferred. Specifically, for example, the compounds described in paragraphs 0028 to 0056 of Japanese Patent Application Publication No. 2001-330725 and the compounds described in paragraphs 0069 to 0126 of Japanese Patent Application Publication No. 2003-295212 can be mentioned.

[0138] The composition layer can contain a polymer. As the polymer, a cellulose ester can be mentioned. As the cellulose ester, the cellulose ester described in paragraph 0178 of Japanese Patent Application Publication No. 2000-155216 can be mentioned.

[0139] The content of the polymer in the composition layer is not particularly limited, but is preferably 0.1 to 10% by mass, more preferably 0.1 to 8% by mass, relative to the total mass of the liquid crystal compound.

[0140] In addition to the above, the composition layer can contain an additive that promotes horizontal alignment or vertical alignment (alignment control agent) to place the liquid crystal compound in a horizontal alignment state or a vertical alignment state.

[0141] (Substrate)

[0142] As described later, when the composition layer is formed, the composition layer is preferably formed on a substrate.

[0143] The substrate is a plate that supports the composition layer.

[0144] As the substrate, a transparent substrate is preferred. In addition, the transparent substrate refers to a substrate having a transmittance of visible light of 60% or more, and the transmittance is preferably 80% or more, more preferably 90% or more.

[0145] The retardation value in the thickness direction of the substrate at a wavelength of 550 nm (Rth(550)) is not particularly limited, but is preferably -110 to 110 nm, more preferably -80 to 80 nm.

[0146] The retardation value in the plane of the substrate at a wavelength of 550 nm (Re(550)) is not particularly limited, but is preferably 0 to 50 nm, more preferably 0 to 30 nm, further preferably 0 to 10 nm.

[0147] As the material forming the substrate, a polymer having excellent optical properties, transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropy is preferred.

[0148] As the polymer film that can be used as the substrate, for example, cellulose acylate film (e.g., triacetyl cellulose film (refractive index 1.48), diacetyl cellulose film, cellulose acetate butyrate film, cellulose acetate propionate film), polyolefin film such as polyethylene and polypropylene, polyester film such as polyethylene terephthalate and polyethylene naphthalate, polyether sulfone film, polymethyl methacrylate film, polyurethane film, polycarbonate film, polysulfone film, polyether film, polymethyl pentene film, polyether ketone film, (meth)acrylonitrile film, and film of a polymer having alicyclic structure (norbornene-based resin (ARTON: product name, manufactured by JSR Corporation., amorphous polyolefin (ZEONEX: product name, manufactured by Zeon Corporation)) can be mentioned.

[0149] Among them, as the material of the polymer film, triacetyl cellulose, polyethylene terephthalate, or a polymer having alicyclic structure is preferable, and triacetyl cellulose is more preferable.

[0150] The substrate can contain various additives (e.g., optical anisotropy adjusting agent, wavelength dispersion adjusting agent, fine particles, plasticizer, ultraviolet inhibitor, deterioration inhibitor, peeling agent, etc.).

[0151] The thickness of the substrate is not particularly limited, but is preferably 10 to 200 μm, more preferably 10 to 100 μm, and further preferably 20 to 90 μm. Also, the substrate can be formed by laminating a plurality of pieces. In order to improve the adhesion of the substrate to a layer provided on the substrate, surface treatment (e.g., glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, flame treatment) can be performed on the surface of the substrate.

[0152] Also, an adhesive layer (primer layer) can be provided on the substrate.

[0153] Also, in order to impart slidability in the conveying process to the substrate, or to prevent the sticking of the back surface to the surface after winding, a polymer layer in which inorganic particles having an average particle diameter of about 10 to 100 nm are mixed at a solid content mass ratio of 5 to 40 mass% can be provided on one side of the substrate.

[0154] The substrate can also be a so-called dummy support. That is, after the manufacturing method of the present application is performed, the substrate can be peeled from the optically anisotropic layer.

[0155] Also, the surface of the substrate can be directly subjected to rubbing treatment. That is, a substrate that has been subjected to rubbing treatment can be used. The direction of the rubbing treatment is not particularly limited, and the optimal direction is appropriately selected depending on the direction in which the liquid crystalline compound is to be oriented.

[0156] The rubbing treatment is a widely used treatment method that can be applied as a liquid crystal alignment treatment process for LCDs (liquid crystal displays). That is, a method of rubbing the surface of a substrate in a certain direction using paper, gauze, felt, rubber, nylon fibers, or polyester fibers, or the like to obtain alignment can be used.

[0157] An alignment film can be provided on the substrate.

[0158] The alignment film can be formed using a rubbing treatment of an organic compound (preferably a polymer), oblique evaporation of an inorganic compound, formation of a layer having microgrooves, or a method of accumulation of an organic compound (e.g., omega-tricosanoic acid, dioctadecylmethylammonium chloride, methyl stearate) based on the Langmuir-Blodgett method (LB film).

[0159] Furthermore, an alignment film that generates an alignment function by imparting an electric field, imparting a magnetic field, or light irradiation (preferably polarized light) is also known.

[0160] The alignment film is preferably formed by a rubbing treatment of a polymer.

[0161] As the polymer included in the alignment film, for example, a methacrylate-based copolymer, a styrene-based copolymer, a polyolefin, a polyvinyl alcohol and a modified polyvinyl alcohol, poly(N-methylol acrylamide), a polyester, a polyimide, a vinyl acetate copolymer, carboxymethyl cellulose, and a polycarbonate described in paragraph 0022 of Japanese Patent Application Publication No. 8-338913 can be given. Furthermore, a silane coupling agent can be used as the polymer.

[0162] Among them, a water-soluble polymer (e.g., poly(N-methylol acrylamide), carboxymethyl cellulose, gelatin, polyvinyl alcohol, modified polyvinyl alcohol) is preferable, gelatin, polyvinyl alcohol, or modified polyvinyl alcohol is more preferable, and polyvinyl alcohol or modified polyvinyl alcohol is further preferable.

[0163] As described above, the alignment film can be formed by coating a solution including the above-described polymer as an alignment film formation material and an arbitrary additive (e.g., a crosslinking agent) on a substrate, followed by heat drying (crosslinking) and rubbing treatment.

[0164] (Step of Process 1A)

[0165] The composition layer including the above-described components is formed in Process 1A, but the step thereof is not particularly limited. For example, a method of coating a composition including the above-described chiral agent and a liquid crystal compound having a polymerizable group on a substrate, and performing a drying treatment as necessary (hereinafter, also simply referred to as "coating method") and a method of forming a composition layer to be transferred to a substrate can be given. Among them, the coating method is preferable from the viewpoint of productivity.

[0166] Next, the coating method will be described in detail.

[0167] The composition used in the coating method contains the above-mentioned chiral agent, the liquid crystal compound having a polymerizable group, and other components (for example, a polymerization initiator, a polymerizable monomer, a surfactant, and a polymer) as needed in addition to the above.

[0168] The content of each component in the composition is preferably adjusted to the content of each component in the composition layer.

[0169] The coating method 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.

[0170] In addition, as needed, after the composition is coated, a process of drying the coating film coated on the substrate can be performed. By performing the drying process, the solvent can be removed from the coating film.

[0171] The film thickness of the coating film is not particularly limited, but is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, and further preferably 0.5 to 10 μm.

[0172] <Process 2A>

[0173] Process 2A is a process of performing a heating treatment on the composition layer to orient the liquid crystal compound in the composition layer. By performing this process, the liquid crystal compound in the composition layer becomes in a prescribed orientation state.

[0174] As the conditions of the heating treatment, the optimum conditions are selected according to the liquid crystal compound used.

[0175] Among them, as the heating temperature, the case of 25 to 250°C is more common, the case of 40 to 150°C is more common, and the case of 50 to 130°C is further more common.

[0176] As the heating time, the case of 0.1 to 60 minutes is more common, and the case of 0.2 to 5 minutes is more common.

[0177] The orientation state of the liquid crystal compound obtained by Process 2A varies according to the helical twisting power of the above-mentioned chiral agent.

[0178] For example, as described later, in order to form an optical anisotropic layer having a first region in which the orientation state of the liquid crystal compound twisted along the helical axis extending in the thickness direction is fixed, and a second region in which the orientation state of the uniformly oriented liquid crystal compound is fixed, the absolute value of the weighted average helical twisting power of the chiral agent in the composition layer formed by Process 1A is preferably 0.0 to 1.9 μm -1more preferably 0.0 to 1.5 μm -1 , further preferably 0.0 to 1.0 μm -1 , particularly preferably 0.0 to 0.5 μm -1 , more particularly preferably 0.0 to 0.02 μm -1 , most preferably zero.

[0179] In the case where the absolute value of the weighted average helical twisting power of the chiral agent in the composition layer is within the above range, if the process 2A is performed, the liquid crystal compounds in the composition are uniformly oriented or the liquid crystal compounds in the composition layer are twisted and oriented along the helical axis extending in the thickness direction.

[0180] In addition, the weighted average helical twisting power of the chiral agent indicates, in the case where two or more chiral agents are contained in the composition, the sum of the values obtained by dividing the product of the helical twisting power of each chiral agent and the concentration (mass %) of each chiral agent in the composition layer by the total concentration (mass %) of the chiral agents in the composition layer. For example, in the case where two chiral agents (chiral agent X and chiral agent Y) are used at the same time, it is represented by the following formula (B).

[0181] Formula (B) weighted average helical twisting power (μm -1 ) = (helical twisting power (μm -1 of chiral agent X x concentration (mass %) of chiral agent X in the composition layer + helical twisting power (μm -1 of chiral agent Y x concentration (mass %) of chiral agent Y in the composition layer) / (concentration (mass %) of chiral agent X in the composition layer + concentration (mass %) of chiral agent Y in the composition layer)

[0182] In the above formula (B), in the case where the chiral agent is right-handed in the helical direction, the helical twisting power thereof is set to a positive value. Also, in the case where the chiral agent is left-handed in the helical direction, the helical twisting power thereof is set to a negative value. That is, for example, in the case of a chiral agent having a helical twisting power of 10 μm -1 , when the helical direction of the helix twisted by the above chiral agent is right-handed, the helical twisting power is represented as 10 μm -1 . On the other hand, when the helical direction of the helix twisted by the above chiral agent is left-handed, the helical twisting power is represented as -10 μm -1 .

[0183] In the case where the absolute value of the weighted average helical twisting power of the chiral agent in the composition layer formed by the process 1A is zero, as Figure 1 indicated, it is possible to form a composition layer 12 in which the liquid crystal compounds LC are uniformly oriented on the substrate 10. In addition, Figure 1is a schematic view of a cross section of the substrate 10 and the composition layer 12. Also, in Figure 1 In the composition layer 12 shown, the chiral agent A and the chiral agent B are present at the same concentration, the helix twisted by the chiral agent A is left-handed, and the helix twisted by the chiral agent B is right-handed. Also, the absolute value of the helical twisting power of the chiral agent A is the same as the absolute value of the helical twisting power of the chiral agent B.

[0184] In the present specification, uniform orientation refers to a state in which the molecular axes of the liquid crystal compounds (for example, corresponding to the long axes in the case of rod-like liquid crystal compounds) are arranged horizontally and in the same azimuth with respect to the surface of the composition layer (optical uniaxiality).

[0185] Here, horizontal does not strictly require horizontal, but indicates an orientation in which the average molecular axis of the liquid crystal compounds within the composition layer forms an inclination angle of less than 20 degrees with respect to the surface of the composition layer.

[0186] Also, the same azimuth does not strictly require the same azimuth, but indicates a state in which, when the azimuth of the slow axis is measured at 20 arbitrary positions in the plane, the maximum difference in the azimuth of the slow axis (the difference between the two slow axis azimuths that differ the most among the 20 slow axis azimuths) is less than 10°.

[0187] Also, in Figure 1 , the manner in which the liquid crystal compounds LC are uniformly oriented is described, but as long as the liquid crystal compounds become a prescribed orientation state, it is not limited to this manner, and for example, as described in detail later, it can also be a manner in which the liquid crystal compounds are twisted and oriented along a helical axis that extends in the thickness direction of the composition layer.

[0188] <Process 3A>

[0189] Process 3A is a process in which, after Process 2A, the composition layer is subjected to light irradiation under conditions in which the oxygen concentration is 1% by volume or more, at an energy density of 300 mJ / cm 2 The following light irradiation is performed for 50 seconds or less. The mechanism of the present process will be described below using the drawings. Also, the following describes the case in which the light irradiation is performed from the side of the substrate 10. Figure 1 The example in which Process 3A is performed on the composition layer 12 shown is described as a representative example.

[0190] As shown in Figure 2 , in Process 3A, the light irradiation is performed from the side of the substrate 10 that is opposite the side of the composition layer 12 (the direction of the hollow arrow in Figure 2 ). Also, in Figure 2 , the light irradiation is performed from the side of the substrate 10, but it can also be performed from the side of the composition layer 12.

[0191] At this time, if the lower side region 12A on the substrate 10 side of the composition layer 12 and the upper side region 12B on the side opposite to the substrate 10 side are compared, the surface of the upper side region 12B is on the air side, and thus the oxygen concentration in the upper side region 12B is high, and the oxygen concentration in the lower side region 12A is low. Therefore, if light is irradiated to the composition layer 12, polymerization of the liquid crystal compound is easily performed in the lower side region 12A, and the orientation state of the liquid crystal compound is fixed. In addition, the chiral agent A is also present in the lower side region 12A, and the chiral agent A is also photosensitive, and the helical twisting power changes. However, since the orientation state of the liquid crystal compound is fixed in the lower side region 12A, even if the process 4A described later, in which a heating treatment is performed on the composition layer to which light is irradiated, is performed, the change in the orientation state of the liquid crystal compound does not occur.

[0192] In addition, since the oxygen concentration in the upper side region 12B is high, even if light is irradiated, polymerization of the liquid crystal compound is hindered by the oxygen, and thus the polymerization is difficult to be performed. Furthermore, the chiral agent A is also present in the upper side region 12B, and thus the chiral agent A is photosensitive, and the helical twisting power changes. Therefore, if the process 4A described later is performed, the orientation state of the liquid crystal compound changes along the helical twisting power in which the change occurs.

[0193] That is, by performing the process 3A, the fixation of the orientation state of the liquid crystal compound is easily performed in the region on the substrate side of the composition layer (lower side region). In addition, the fixation of the orientation state of the liquid crystal compound is difficult to be performed in the region on the side opposite to the substrate side of the composition layer (upper side region), and becomes a state in which the helical twisting power changes depending on the photosensitive chiral agent A.

[0194] The process 3A is performed under a condition in which the oxygen concentration is 1% by volume or more. Among them, in the optically anisotropic layer, the oxygen concentration is preferably 2% by volume or more, and more preferably 5% by volume or more, from the viewpoint of easily forming regions in which the orientation state of the liquid crystal compound is different. There is no particular limitation on the upper limit, but 100% by volume can be given as an example.

[0195] The time of the light irradiation in the process 3A is 50 seconds or less, and is preferably 30 seconds or less, and more preferably 10 seconds or less, from the viewpoint of easily forming the prescribed optically anisotropic layer and the viewpoint of productivity. There is no particular limitation on the lower limit, but 0.1 second or more, and more preferably 0.2 second or more, is preferable from the viewpoint of the curing of the liquid crystal compound.

[0196] The light irradiation amount in the process 3A is 300 mJ / cm 2 From the viewpoint of easily forming the prescribed optically anisotropic layer and the viewpoint of productivity, 250 mJ / cm 2 More preferably, 200 mJ / cm 2The following is not a specific lower limit, but from the viewpoint of curing the liquid crystal compound, 1 mJ / cm is preferred. 2 The above is preferred, with 5 mJ / cm² being more ideal. 2 above.

[0197] If the duration and amount of light irradiation do not meet the above-mentioned necessary conditions, the specified optical anisotropy layer cannot be formed.

[0198] In addition, the light irradiation in step 3A of the first embodiment is preferably carried out at 15 to 70°C (preferably 25 to 50°C).

[0199] The light used for irradiation only needs to be light that is photosensitive to chiral reagent A. That is, there are no particular restrictions as long as the light used for irradiation is an activating ray or radiation that changes the helical torsional force of chiral reagent A. Examples include the bright-line spectrum of a mercury lamp, far-ultraviolet light represented by an excimer laser, extreme ultraviolet light, X-rays, ultraviolet light, and electron beams. Among these, ultraviolet light is preferred.

[0200] <Process 4A>

[0201] Step 4A is as follows: After step 3A, the composition layer is heat-treated at a higher temperature than during light irradiation. By performing this step, the orientation state of the liquid crystal compound changes in the region where the helical torsional force of chiral reagent A changes in the light-irradiated composition layer. More specifically, this step is as follows: the composition layer after step 3A is heat-treated at a higher temperature than during irradiation to orient the liquid crystal compound in the composition layer that was not fixed in step 3A.

[0202] The mechanism of this process will be described below using the accompanying drawings.

[0203] As mentioned above, if for Figure 1 In the embodiment of step 3A of the composition layer 12 shown, the orientation state of the liquid crystal compound is fixed in the lower region 12A, while polymerization of the liquid crystal compound is difficult to occur in the upper region 12B, and the orientation state of the liquid crystal compound is not fixed. Furthermore, the helical torsional force of the chiral reagent A changes in the upper region 12B. If this helical torsional force of the chiral reagent A changes, compared with the state before light irradiation, the force that twists the liquid crystal compound in the upper region 12B changes. This point will be explained in more detail.

[0204] As mentioned above, in Figure 1In the composition layer 12 shown, the chiral agent A and the chiral agent B are present at the same concentration, the helix twisted by the chiral agent A is left-handed, and the helix twisted by the chiral agent B is right-handed. Also, the absolute value of the helical twisting power of the chiral agent A is the same as the absolute value of the helical twisting power of the chiral agent B. Therefore, the weighted average helical twisting power of the chiral agents in the composition layer before light irradiation is 0.

[0205] The above-described manner is shown in Figure 4 . In Figure 4 , the vertical axis represents "helical twisting power of chiral agent (pm -1 ) x concentration of chiral agent (mass %)", and the farther the value is from zero, the greater the helical twisting power. First, the relationship between the chiral agent A and the chiral agent B in the composition layer before light irradiation corresponds to the point of time when the light irradiation amount is 0, and corresponds to a state where the absolute value of "helical twisting power of chiral agent A (pm -1 ) x concentration of chiral agent A (mass %)" is equal to the absolute value of "helical twisting power of chiral agent B (pm -1 ) x concentration of chiral agent B (mass %)". That is, the helical twisting power of both the left-handed chiral agent A and the right-handed chiral agent B cancel each other out.

[0206] In the upper region 12B in this state, light irradiation is performed, and as shown in Figure 4 , in the case where the helical twisting power of the chiral agent A decreases depending on the light irradiation amount, as shown in Figure 5 , the weighted average helical twisting power of the chiral agents in the upper region 12B becomes large, and the right-handed helical twisting power becomes strong. That is, regarding the helical twisting power of the helix of the twisted liquid crystal compound, the greater the irradiation amount, the greater the helical twisting power in the direction (+) of the helix twisted by the chiral agent B.

[0207] Therefore, if a heating treatment is performed on the composition layer 12 after the process 3A in which the weighted average helical twisting power changes, as shown in Figure 3 , in the upper region 12B, the liquid crystal compound LC is twisted and aligned along the helical axis extending in the thickness direction of the composition layer 12.

[0208] On the other hand, as described above, in the lower region 12A of the composition layer 12, the polymerization of the liquid crystal compound is performed at the process 3A, and the alignment state of the liquid crystal compound is fixed, so the re-alignment of the liquid crystal compound is not performed.

[0209] As described above, by performing the process 4A, a plurality of regions in which the alignment state of the liquid crystal compound is different are formed in the thickness direction of the composition layer.

[0210] In addition, in the above Figure 4 andFigure 5 In the above, a method using a chiral agent A that has a helical twisting power that decreases by light irradiation is described, but the method is not limited to this. For example, a chiral agent A that has a helical twisting power that increases by light irradiation can be used. At this time, the helical twisting power of the chiral agent A twisted by light irradiation becomes large, and the liquid crystal compound is twisted and aligned in the direction of rotation of the chiral agent A.

[0211] Also, in the above Figure 4 and Figure 5 , a method using both a chiral agent A and a chiral agent B is described, but the method is not limited to this. For example, a method using two kinds of chiral agent A can also be used. Specifically, a method using a chiral agent Al that causes left-handedness and a chiral agent A2 that causes right-handedness can also be used. The chiral agent Al and the chiral agent A2 can each independently be a chiral agent that has a helical twisting power that increases or a chiral agent that has a helical twisting power that decreases. For example, a chiral agent that causes left-handedness and has a helical twisting power that increases by light irradiation and a chiral agent that causes right-handedness and has a helical twisting power that decreases by light irradiation can be used together.

[0212] The heat treatment is performed at a higher temperature than at the time of light irradiation.

[0213] The difference between the temperature of the heat treatment and the temperature at the time of light irradiation is preferably 5°C or more, more preferably 10 to 110°C, and more preferably 20 to 110°C.

[0214] The temperature of the heat treatment is preferably higher than the temperature at the time of light irradiation and a temperature at which the liquid crystal compound in the composition layer that has not been fixed is aligned, and more specifically, the temperature is often 35 to 250°C, more often 50 to 150°C, further more often more than 50°C and 150°C or less, and particularly often 60 to 130°C.

[0215] As the heat treatment time, the time is often 0.01 to 60 minutes, and more often 0.03 to 5 minutes.

[0216] Also, the absolute value of the weighted average helical twisting power of the chiral agent in the composition layer after light irradiation is not particularly limited, but the absolute value of the difference between the weighted average helical twisting power of the chiral agent in the composition layer after light irradiation and the weighted average helical twisting power before light irradiation is preferably 0.05 pm or more, more preferably 0.1 to 10.0 pm, and further more preferably 0.1 to 10.0 pm. -1 More preferably, the absolute value of the difference is 0.05 to 10.0 pm. -1 Further more preferably, the absolute value of the difference is 0.1 to 10.0 pm. -1

[0217] <Process 5A>

[0218] ​Process 5A is a process of subjecting the composition layer to a curing treatment to form an optically anisotropic layer having a plurality of regions with different alignment states of the liquid crystal compound in the thickness direction. By carrying out this process, the alignment state of the liquid crystal compound in the composition layer is fixed, and as a result, a prescribed optically anisotropic layer can be formed. In addition, for example, in the case where the composition layer 12 shown in FIG. 1 is subjected to a curing treatment, an optically anisotropic layer having a first region in which the alignment state of the liquid crystal compound twisted around the helical axis extending in the thickness direction is fixed and a second region in which the alignment state of the uniformly aligned liquid crystal compound is fixed can be formed. Figure 3

[0219] The method of the curing treatment is not particularly limited, and examples of the method include a photocuring treatment and a thermal curing treatment. Among them, a light irradiation treatment is preferred, and an ultraviolet irradiation treatment is more preferred.

[0220] The ultraviolet irradiation uses a light source such as an ultraviolet lamp.

[0221] The amount of light (e.g., ultraviolet) irradiation is not particularly limited, but is generally preferably 100 to 800 mJ / cm 2 around.

[0222] The environment at the time of light irradiation is not particularly limited, and the light irradiation can be carried out in air or in an inactive environment. In particular, the light irradiation is preferably carried out under conditions where the oxygen concentration is less than 1% by volume.

[0223] In the case where the photocuring treatment is carried out as the curing treatment, the temperature conditions at the time of photocuring are not particularly limited, and the temperature is only required to be a temperature at which the alignment state of the liquid crystal compound in process 4A is maintained, and the difference between the temperature of the heating treatment in process 4A and the temperature at the time of the photocuring treatment is preferably within 100°C, and more preferably within 80°C.

[0224] In addition, the temperature of the heating treatment in process 4A and the temperature at the time of the photocuring treatment are preferably the same or the temperature at the time of the photocuring treatment is lower.

[0225] In the optically anisotropic layer obtained by carrying out the curing treatment, the alignment state of the liquid crystal compound is fixed.

[0226] In addition, in the present specification, the "fixed" state is the most typical and preferred mode in which the alignment of the liquid crystal compound is maintained. This is not limited thereto, and specifically, it is more preferred that the state in which there is no flowability in the layer and the fixed alignment mode can be stably maintained without changing the alignment mode due to an external field or an external force in a temperature range of generally 0 to 50°C, and more severely, -30 to 70°C.

[0227] ​In addition, in the optically anisotropic layer, the composition in the final layer no longer needs to exhibit liquid crystallinity.

[0228] The thickness of the optically anisotropic layer is not particularly limited, but is preferably from 0.05 to 10 μm, more preferably from 0.1 to 8.0 μm, and further preferably from 0.2 to 6.0 μm.

[0229] In the above Figure 3 In the above-described manner, the optically anisotropic layer is produced in which the first region in which the orientation state of the liquid crystal compound twisted to the right along the helical axis extending in the thickness direction is fixed and the second region in which the orientation state of the uniformly oriented liquid crystal compound is fixed, but the present application is not limited to the above-described manner.

[0230] For example, the twisted orientation of the liquid crystal compound can also be left twist. That is, the direction of the twisted orientation of the liquid crystal compound can be left twist (counterclockwise twist), or right twist (clockwise twist).

[0231] Further, as the orientation state of the liquid crystal compound in the above-described second region, an orientation other than uniform orientation can be used, and in the case where the liquid crystal compound is a rod-shaped liquid crystal compound, as the orientation state thereof, for example, nematic orientation (a state in which a nematic phase is formed), smectic orientation (a state in which a smectic phase is formed), cholesteric orientation (a state in which a cholesteric phase is formed), and hybrid orientation can be mentioned. In the case where the liquid crystal compound is a discotic liquid crystal compound, as the orientation state thereof, nematic orientation, columnar orientation (a state in which a columnar phase is formed), and cholesteric orientation can be mentioned.

[0232] Further, as the specific method of the orientation state of the liquid crystal compound, a publicly known method can be mentioned. For example, a method in which the cross section of the optically anisotropic layer is observed using a polarizing microscope to determine the orientation state of the liquid crystal compound can be mentioned.

[0233] Further, in the above Figure 3 In the above-described manner, the optically anisotropic layer is produced in which the first region in which the orientation state of the liquid crystal compound twisted to the right along the helical axis extending in the thickness direction is fixed and the second region in which the orientation state of the uniformly oriented liquid crystal compound is fixed, but the present application is not limited to the above-described manner.

[0234] In the case where the optically anisotropic layer has two regions in which the orientation state of the liquid crystal compound is different, the ratio of the thickness of the region having a greater thickness to the thickness of the region having a smaller thickness in the two regions is not particularly limited, but is preferably more than 1 and 9 or less, and more preferably more than 1 and 4 or less.

[0235] Further, in the case where the thicknesses of the two regions are the same, the above-described ratio is 1.

[0236] Further, the optically anisotropic layer in the first embodiment can be an optically anisotropic layer having a first region in which the orientation state of the liquid crystal compound twistedly oriented along a helical axis extending in the thickness direction is fixed, and a second region in which the orientation state of the liquid crystal compound uniformly oriented is fixed.

[0237] As a method of forming a region in which the angle of the twist angle of the liquid crystal compound differs, for example, a method of increasing the absolute value of the weighted average helical twisting power of the chiral agent in the composition layer formed by the above-described process 1A (for example, exceeding 0 μm -1 ) can be given. In the case where the absolute value of the weighted average helical twisting power of the chiral agent in the composition layer formed by process 1A is large, first, as shown in Figure 6 , in the composition layer 120 in which process 2 is implemented, the liquid crystal compound is twistedly oriented along a helical axis extending in the thickness direction. If the above-described process is implemented on such a composition layer, the twisted orientation of the liquid crystal compound is directly fixed in the region in the composition layer in which the oxygen concentration is low (the lower region 120A in Figure 7 ), and the helical twisting power changes in the region in the composition layer in which the oxygen concentration is high (the upper region 120B in Figure 7 ), so that as a result, after process 5A is implemented, a region in which the angle of the twist angle of the liquid crystal compound differs can be formed.

[0238] The optical properties in the optically anisotropic layer in the first embodiment are not particularly limited, and the optimum value is selected depending on the use. Hereinafter, as an example, the case of the optically anisotropic layer produced by the above-described steps, which has a first region in which the orientation state of the liquid crystal compound twistedly oriented along a helical axis extending in the thickness direction is fixed, and a second region in which the orientation state of the liquid crystal compound uniformly oriented is fixed, is described in detail.

[0239] In the case where the thickness of the first region of the above-described optically anisotropic layer is set to d1 and the refractive index anisotropy of the first region measured at a wavelength of 550 nm is set to Δn1, from the viewpoint that the optically anisotropic layer can be preferably applied to a circularly polarizing plate, the first region preferably satisfies the following formula (1A-1).

[0240] Formula (1A-1) 100 nm ≤ Δn1d1≤ 240 nm

[0241] Further, the formula (1A-2) is more preferably satisfied, and the formula (1A-3) is further preferably satisfied.

[0242] Formula (1A-2) 120 nm ≤ Δn1d1≤ 220 nm

[0243] Formula (1A-3) 140 nm < Δn1d1 < 200 nm

[0244] The absolute value of the twist angle of the liquid crystal compound in the first region is not particularly limited, but from the viewpoint of being able to preferably apply the optically anisotropic layer to a circular polarizing plate, it is preferably 50 to 110°, and more preferably 60 to 100°.

[0245] In addition, first, the twist alignment of the liquid crystal compound means that the liquid crystal compound twists from one surface (the surface on the side of the substrate 10 in Formula (1A-1)) to the other surface (the surface on the side opposite to the substrate 10 in Formula (1A-1)) with the thickness direction of the first region as the axis. Therefore, the above-mentioned twist angle indicates the angle formed by the molecular axis (the long axis in the case of a rod-like liquid crystal compound) of the liquid crystal compound on one surface of the first region and the molecular axis of the liquid crystal compound on the other surface of the first region. Figure 3 Figure 3 Regarding the measurement method of the twist angle, Axoscan of Axometrics Co., Ltd. was used, and measurement was performed using the device analysis software of Axometrics Co., Ltd.

[0246] Also, in the case where the thickness of the second region of the above-mentioned optically anisotropic layer is set to d2 and the refractive index anisotropy of the second region measured at a wavelength of 550 nm is set to Δn2, from the viewpoint of being able to preferably apply the optically anisotropic layer to a circular polarizing plate, the second region preferably satisfies the following Formula (2A-1).

[0247] Formula (2A-1) 100 nm < Δn2d2 < 240 nm

[0248] Further, more preferably, Formula (2A-2) is satisfied, and further preferably, Formula (2A-3) is satisfied.

[0249] Formula (2A-2) 120 nm < Δn2d2 < 220 nm

[0250] Formula (2A-3) 140 nm < Δn2d2 < 200 nm

[0251] Formula (2A-3) 140 nm < Δn2d2 < 200 nm

[0252] The second region is a region in which the alignment state of the uniformly aligned liquid crystal compound is fixed. The definition of uniform alignment is as described above.

[0253] In addition, the difference between Δn1d1 and Δn2d2 is not particularly limited, but from the viewpoint of being able to preferably apply the optically anisotropic layer to a circular polarizing plate, it is preferably -50 to 50 nm, and more preferably -30 to 30 nm.

[0254] ​Further, in the case where the optically anisotropic layer in the first embodiment contains two regions in which the alignment state of the liquid crystal compounds that are twisted and aligned along the helical axis extending in the thickness direction is fixed, and one region is set as region A and the other region is set as region B, in the case where the thickness of region A is set as dA and the refractive index anisotropy of region A measured at a wavelength of 550 nm is set as ΔnA, from the viewpoint that the optically anisotropic layer can be preferably applied to a circularly polarizing plate, region A preferably satisfies the following formula (3A-1).

[0255] Formula (3A-1) 205 nm ≤ ΔnA dA ≤ 345 nm

[0256] Further, the formula (3A-2) is more preferably satisfied, and the formula (3A-3) is further preferably satisfied.

[0257] Formula (3A-2) 225 nm ≤ ΔnA dA ≤ 325 nm

[0258] Formula (3A-3) 245 nm ≤ ΔnA dA ≤ 305 nm

[0259] The absolute value of the twist angle of the liquid crystal compounds in region A is not particularly limited, but from the viewpoint that the optically anisotropic layer can be preferably applied to a circularly polarizing plate, it is preferably more than 0° and 60° or less, and more preferably 10 to 50°.

[0260] In the case where the thickness of region B is set as d2 and the refractive index anisotropy of region B measured at a wavelength of 550 nm is set as ΔnB, from the viewpoint that the optically anisotropic layer can be preferably applied to a circularly polarizing plate, region B preferably satisfies the following formula (4A-1).

[0261] Formula (4A-1) 70 nm ≤ ΔnB dB ≤ 210 nm

[0262] Further, the formula (4A-2) is more preferably satisfied, and the formula (4A-3) is further preferably satisfied.

[0263] Formula (4A-2) 90 nm ≤ ΔnB dB ≤ 190 nm

[0264] Formula (4A-3) 110 nm ≤ ΔnB dB ≤ 170 nm

[0265] The absolute value of the twist angle of the liquid crystal compounds in region B is not particularly limited, but from the viewpoint that the optically anisotropic layer can be preferably applied to a circularly polarizing plate, it is preferably 50 to 110°, and more preferably 60 to 100°.

[0266] Also, in the case where the optically anisotropic layer formed in the first embodiment of the method for producing an optically anisotropic layer of the present application has two regions in which the orientation state of the liquid crystal compound is different in the thickness direction (hereinafter, the two regions are referred to as region X and region Y), the slow axis on the surface of region X on the side of region Y is more often parallel to the slow axis on the surface of region Y on the side of region X.

[0267] The optical properties in the optically anisotropic layer in the first embodiment are not limited to the above-described manner, and for example, in the case where the optically anisotropic layer has two regions in which the orientation state of the liquid crystal compound is different in the thickness direction, it is preferable that the two regions respectively satisfy the optical properties (the relationship of the twist angle of the liquid crystal compound, Δnd, Re B, and the slow axis) of the first optically anisotropic layer and the second optically anisotropic layer described in Japanese Patent No. 5960743.

[0268] Also, as another manner, in the case where the optically anisotropic layer has two regions in the thickness direction, it is preferable that the two regions satisfy the optical properties (the relationship of the twist angle of the liquid crystal compound, Δn1d1, Δn2d2, and the slow axis) of the first optically anisotropic layer and the second optically anisotropic layer described in Japanese Patent No. 5753922.

[0269] The optically anisotropic layer in the first embodiment preferably exhibits reverse wavelength dispersion.

[0270] That is, the in-plane retardation of the optically anisotropic layer measured at a wavelength of 450 nm, that is, Re (450), the in-plane retardation of the optically anisotropic layer measured at a wavelength of 550 nm, that is, Re (550), and the in-plane retardation of the optically anisotropic layer measured at a wavelength of 650 nm, that is, Re (650), preferably satisfy the relationship of Re (450) ≤ Re (550) ≤ Re (650).

[0271] The optical properties of the optically anisotropic layer in the first embodiment are not particularly limited, but it is preferable to function as a λ / 4 plate.

[0272] The λ / 4 plate is a plate having a function of converting linearly polarized light of a certain specific wavelength into circularly polarized light (or converting circularly polarized light into linearly polarized light), and refers to a plate (optically anisotropic layer) in which the in-plane retardation Re (λ) at a specific wavelength λ nm satisfies Re (λ) = λ / 4.

[0273] This formula is satisfied at any wavelength (for example, 550 nm) in the visible light region, but it is preferable that the in-plane retardation Re (550) at a wavelength of 550 nm satisfy the relationship of 110 nm ≤ Re (550) ≤ 180 nm.

[0274] <<Second Embodiment>>

[0275] The second embodiment of the method for manufacturing the optically anisotropic layer of the present application includes the following Step 1B to Step 5B. As described later, in the second embodiment, an optically anisotropic layer having a region in which a cholesteric liquid crystal phase is fixed is formed.

[0276] Step 1B: a step of forming a composition layer containing at least a chiral agent including a photosensitive chiral agent whose helical twisting power changes by light irradiation and a liquid crystal compound having a polymerizable group

[0277] Step 2B: a step of performing a heat treatment on the composition layer to orient the liquid crystal compound in the composition layer to form a cholesteric liquid crystal phase

[0278] Step 3B: a step of, after Step 2B, performing light irradiation on the composition layer at a temperature of 300 mJ / cm 2 the following step of performing light irradiation for 50 seconds or less

[0279] Step 4B: a step of, after Step 3B, performing a heat treatment on the composition layer at a higher temperature than the temperature at the time of light irradiation

[0280] Step 5B: a step of, after Step 4B, performing a curing treatment on the composition layer to form an optically anisotropic layer having a plurality of regions in which the orientation state of the liquid crystal compound differs in the thickness direction

[0281] As described later, in the second embodiment, in order to manufacture an optically anisotropic layer having the above-described characteristics, the total content of the chiral agents (the total content of all the chiral agents) in the composition layer is preferably more than 5.0% by mass with respect to the total mass of the liquid crystal compound.

[0282] Regarding the difference between the first embodiment and the second embodiment, the content of the chiral agent can be mainly cited.

[0283] Hereinafter, the steps of each of the above-described steps will be described in detail.

[0284] <Step 1B>

[0285] Step 1B is a step of forming a composition layer containing at least a chiral agent including a photosensitive chiral agent whose helical twisting power changes by light irradiation and a liquid crystal compound having a polymerizable group. By performing this step, a composition layer on which the light irradiation treatment described later is performed can be formed.

[0286] The chiral agents (chiral agent A and chiral agent B) and the liquid crystal compound contained in the composition layer are as described in Step 1A.

[0287] Also, as explained in the above procedure 1A, the composition layer can contain other components in addition to the chiral agent and the liquid crystal compound.

[0288] In procedure 1B, the chiral agent is contained in the composition layer to form a cholesteric liquid crystal phase in procedure 2B described later.

[0289] In the second embodiment, the total content of the chiral agent in the composition layer (total content of all chiral agents) is not particularly limited, but from the viewpoint of easily controlling the orientation state of the liquid crystal compound, it is preferably more than 5.0% by mass, more preferably 5.5% by mass or more, and further preferably 6.0% by mass or more, relative to the total mass of the liquid crystal compound. The upper limit is not particularly limited, but it is preferably 25% by mass or less, more preferably 20% by mass or less, and further preferably 15% by mass or less.

[0290] The content of the chiral agent A in the chiral agent is not particularly limited, but from the viewpoint of easily controlling the orientation state of the liquid crystal compound, it is preferably 5 to 95% by mass, and more preferably 10 to 90% by mass, relative to the total mass of the chiral agent.

[0291] The absolute value of the helical twisting power of the chiral agent in the composition layer formed by procedure 1B is preferably 10 μm -1 More preferably, 15 μm -1 Further preferably, 20 μm -1 or less. The upper limit is not particularly limited, but 250 μm -1 The case of 200 μm -1 The case of 200 μm

[0292] Also, in the case where two or more chiral agents are contained in the composition, the absolute value of the weighted average helical twisting power of the chiral agent in the composition layer formed by procedure 1B is preferably within the above range.

[0293] In the case where the helical twisting power or the absolute value of the helical twisting power of the chiral agent in the composition layer is within the above range, the liquid crystal compound in the composition is cholesterically oriented by procedure 2B.

[0294] The definition of the weighted average helical twisting power is as described above.

[0295] As for the method of forming the composition layer in procedure 1B, the same formation method as that of the composition layer in the above procedure 1A can be cited.

[0296] <Procedure 2B>

[0297] Process 2B is a process of performing a heating treatment on the composition layer to orient the liquid crystal compound in the composition layer to form a cholesteric liquid crystal phase. By performing this process, the liquid crystal compound in the composition layer becomes in a prescribed orientation state.

[0298] As the conditions of the heating treatment, the optimum conditions are selected depending on the liquid crystal compound used.

[0299] As the heating temperature, 25 to 250°C is more common, 40 to 150°C is more common, and 50 to 130°C is further more common.

[0300] As the heating time, 0.1 to 60 minutes is more common, and 0.2 to 5 minutes is more common.

[0301] Process 3B

[0302] Process 3B is a process of, after Process 2B, performing light irradiation on the composition layer from the side of the substrate 10 opposite to the side of the composition layer 220 (the direction of the hollow arrow in FIG. 10) under conditions where the oxygen concentration is 1 vol% or more and the light intensity is 300 mJ / cm2or more. 2 The following light irradiation is performed for 50 seconds or less. The mechanism of this process is described below using the drawings. In addition, Figure 8 The manner shown in FIG. 10 corresponds to the manner in which the liquid crystal compound forms a cholesteric liquid crystal phase.

[0303] As shown in FIG. 10, in Process 3B, light irradiation is performed from the side of the substrate 10 opposite to the side of the composition layer 220 (the direction of the hollow arrow in FIG. 10) under conditions where the oxygen concentration is 1 vol% or more and the light intensity is 300 mJ / cm2or more. Figure 8 Figure 8 In FIG. 10, light irradiation is performed from the side of the substrate 10, but it can also be performed from the side of the composition layer 220. Figure 8

[0304] At this time, if the lower region 220A on the side of the substrate 10 and the upper region 220B on the side opposite to the side of the substrate 10 of the composition layer 220 are compared, the surface of the upper region 220B is on the air side, and thus the oxygen concentration in the upper region 220B is high, and the oxygen concentration in the lower region 220A is low. Therefore, if light irradiation is performed on the composition layer 220, polymerization of the liquid crystal compound is easily performed in the lower region 220A, and the orientation state of the liquid crystal compound is fixed. In addition, the chiral agent A is also present in the lower region 220A, and the chiral agent A also becomes photosensitive and the helical twisting power changes. However, since the orientation state of the liquid crystal compound is fixed in the lower region 220A, even if Process 4B, which is described later, of performing a heating treatment on the composition layer on which light irradiation is performed, is performed, changes in the orientation state of the liquid crystal compound do not occur.

[0305] ​​Furthermore, due to the high oxygen concentration in the upper region 220B, the polymerization of the liquid crystal compound is hindered by oxygen even under light irradiation, making polymerization difficult. Moreover, chiral reagent A is also present in the upper region 220B, and therefore, the helical torsion force changes upon photosensitive reaction to chiral reagent A. Thus, if step 4B is performed later, the orientation state of the liquid crystal compound changes along with the altered helical torsion force.

[0306] That is, by performing step 3B, the alignment state of the liquid crystal compound can be easily fixed in the substrate-side region (lower region) of the composition layer. However, it is difficult to fix the alignment state of the liquid crystal compound in the region (upper region) on the opposite side of the composition layer from the substrate side, and the spiral torsion force varies depending on the photosensitive chiral reagent A.

[0307] The various conditions for light irradiation in step 3B (oxygen concentration, irradiation time, irradiation amount, etc.) are the same as those for light irradiation in step 3A above.

[0308] <Process 4B>

[0309] Step 4B is as follows: After step 3B, the composition layer is heat-treated at a higher temperature than during light irradiation. By performing this step, the orientation state of the liquid crystal compound changes in the region where the helical torsional force of chiral reagent A changes in the light-irradiated composition layer. More specifically, this step is as follows: the composition layer after step 3B is heat-treated at a higher temperature than during irradiation to orient the liquid crystal compound in the composition layer that was not fixed in step 3B.

[0310] The mechanism of this process will be described below using the accompanying drawings.

[0311] As mentioned above, if for Figure 8 In step 3B of the illustrated composition layer 220, the orientation state of the liquid crystal compound is fixed in the lower region 220A, while polymerization of the liquid crystal compound is difficult to occur in the upper region 220B, and the orientation state of the liquid crystal compound is not fixed. Furthermore, the helical torsional force of the chiral reagent A changes in the upper region 220B. If this helical torsional force of the chiral reagent A changes, compared to the state before light irradiation, the force that twists the liquid crystal compound in the upper region 220B changes. This will be explained in more detail.

[0312] Furthermore, in the following description, the case in which the composition layer 220 contains a chiral reagent A that is twisted in a left-handed helical direction and whose helical torsional force is reduced by light irradiation will be described in detail.

[0313] Light is irradiated in the upper region 220B of this state, such as... Figure 10As shown, in a case where the helical twisting power of the chiral agent A decreases depending on the light irradiation amount, the helical twisting power of the chiral agent in the upper region 220B becomes small.

[0314] Therefore, if the composition layer 220 after the process 3B in which the helical twisting power changes is subjected to a heat treatment to promote reorientation of the liquid crystal compound, as shown in Figure 9 As shown, in the upper region 220B, the helical pitch of the cholesteric liquid crystal layer becomes large.

[0315] On the other hand, as described above, in the lower region 220A of the composition layer 220, the polymerization of the liquid crystal compound is performed at the process 3B and the orientation state of the liquid crystal compound is fixed, and thus reorientation of the liquid crystal compound does not occur.

[0316] As described above, by performing the process 4B, a plurality of cholesteric liquid crystal phases having different helical pitches are formed in the thickness direction of the composition layer.

[0317] In addition, in the above Figure 8 and Figure 9 , a method of using a chiral agent whose helical twisting power decreases by light irradiation as the chiral agent A is described, but is not limited to this method. For example, a chiral agent whose helical twisting power increases by light irradiation can be used as the chiral agent A.

[0318] Also, in the above Figure 8 and Figure 9 , a method of using a chiral agent whose twisted helical direction is left-handed as the chiral agent A is described, but is not limited to this method. For example, a chiral agent whose twisted helical direction is right-handed can be used as the chiral agent A.

[0319] Also, in the above Figure 8 and Figure 9 , a method of using only one kind of chiral agent A is described, but is not limited to this method. For example, a method of using two kinds of chiral agents A can be used, and a method of simultaneously using a chiral agent A and a chiral agent B can be used.

[0320] The heat treatment is performed at a higher temperature than at the time of light irradiation.

[0321] The difference between the temperature of the heat treatment and the temperature at the time of light irradiation is preferably 5°C or more, more preferably 10 to 110°C, and more preferably 20 to 110°C.

[0322] The temperature of the heating treatment is preferably higher than the temperature at the time of the light irradiation and is a temperature at which the liquid crystal compound not fixed in the composition layer is oriented, and more specifically, cases of 40 to 250°C are common, cases of 50 to 150°C are more common, cases of more than 50°C and 150°C or lower are further more common, and cases of 60 to 130°C are especially common.

[0323] As the heating time, cases of 0.01 to 60 minutes are common, and cases of 0.03 to 5 minutes are more common.

[0324] Also, the absolute value of the helical twisting power of the chiral agent in the composition layer after the light irradiation is not particularly limited, but the absolute value of the difference between the helical twisting power of the chiral agent in the composition layer after the light irradiation and the helical twisting power before the light irradiation is preferably 0.05 μm -1 More preferably, it is 0.05 to 10.0 μm -1 Further preferably, it is 0.1 to 10.0 μm -1 .

[0325] Also, in the case where two or more chiral agents are included in the composition, the absolute value of the difference between the weighted average helical twisting power of the chiral agent in the composition layer after the light irradiation and the weighted average helical twisting power before the light irradiation is preferably 0.05 μm -1 More preferably, it is 0.05 to 10.0 μm -1 Further preferably, it is 0.1 to 10.0 μm -1 .

[0326] <Process 5B>

[0327] Process 5B is a process in which, after Process 4B, a curing treatment is performed on the composition layer to form an optically anisotropic layer having a plurality of regions in which the orientation state of the liquid crystal compound differs in the thickness direction. By performing this process, the orientation state of the liquid crystal compound in the composition layer is fixed, and as a result, a prescribed optically anisotropic layer can be formed. Also, by performing this process, an optically anisotropic layer in which the cholesteric liquid crystal phase is fixed and which has a plurality of regions in which the pitch of the cholesteric liquid crystal phase differs in the thickness direction can be formed. Cases in which the length of the pitch in each region is constant are common. That is, by performing this process, an optically anisotropic layer in which the cholesteric liquid crystal phase is fixed and which has a plurality of regions in which the pitch of the cholesteric liquid crystal phase differs in the thickness direction and in which the pitch in each region is constant can be formed.

[0328] As the method of the curing treatment in Process 5B, the method of the curing treatment in Process 5A can be cited.

[0329] The thickness of the optically anisotropic layer is not particularly limited, but is preferably 0.05 to 10 μm, more preferably 0.1 to 8.0 μm, and further preferably 0.2 to 6.0 μm.

[0330] In the optically anisotropic layer having a plurality of regions with different helical pitches of the cholesteric liquid crystal phase fixed therein along the thickness direction, the selective reflection center wavelengths of the cholesteric liquid crystal phase in each region are different. For example, the optically anisotropic layer can be one having a region with a cholesteric liquid crystal phase fixed therein to reflect blue light along the thickness direction and a region with a cholesteric liquid crystal phase fixed therein to reflect green light along the thickness direction, or one having a region with a cholesteric liquid crystal phase fixed therein to reflect green light along the thickness direction and a region with a cholesteric liquid crystal phase fixed therein to reflect red light along the thickness direction.

[0331] In the present specification, the selective reflection center wavelength means, in the case where the minimum value of the transmittance in the substance (member) to be the object is set to T min (%), the half-value transmittance represented by the following equation: T 1 / 2 (%) of two wavelengths.

[0332] The equation for the half-value transmittance: T 1 / 2 = 100 - (100 - T min ) ÷ 2

[0333] Further, the light in the wavelength region of 420 nm or more and less than 500 nm in the visible light is blue light (B light), the light in the wavelength region of 500 nm or more and less than 600 nm is green light (G light), and the light in the wavelength region of 600 nm or more and less than 700 nm is red light (R light).

[0334] Further, in the manner shown in Figure 9 , the optically anisotropic layer has two regions with different orientation states of the liquid crystal compound, but the present application is not limited to the above manner, and the optically anisotropic layer can have three or more regions with different orientation states of the liquid crystal compound. As described above, the optically anisotropic layer having three or more regions with different orientation states of the liquid crystal compound can be formed, for example, by performing the procedure 3B multiple times with the conditions changed.

[0335] As the optically anisotropic layer as described above, for example, there can be mentioned an optically anisotropic layer having a region with a cholesteric liquid crystal phase fixed therein to reflect blue light along the thickness direction, a region with a cholesteric liquid crystal phase fixed therein to reflect green light along the thickness direction, and a region with a cholesteric liquid crystal phase fixed therein to reflect red light along the thickness direction.

[0336] <<3rd Embodiment>>

[0337] The manufacturing method of the optically anisotropic layer of the present application according to the third embodiment includes the following Step 1C to Step 5C. As described later, in the third embodiment, an optically anisotropic layer having a region in which the orientation state of the liquid crystal compound is fixed so as to be inclined or perpendicularly oriented with respect to the layer surface is formed.

[0338] Step 1C: a step of forming a composition layer containing a photosensitive compound whose polarity changes by light irradiation and a liquid crystal compound having a polymerizable group

[0339] Step 2C: a step of subjecting the composition layer to a heating treatment to orient the liquid crystal compound in the composition layer

[0340] Step 3C: after Step 2C, a step of subjecting the composition layer to light irradiation at 300 mJ / cm 2 the following light irradiation is performed for 50 seconds or less

[0341] Step 4C: after Step 3C, a step of subjecting the composition layer to a heating treatment at a higher temperature than at the time of light irradiation

[0342] Step 5C: after Step 4C, a step of subjecting the composition layer to a curing treatment to form an optically anisotropic layer having a plurality of regions in which the orientation state of the liquid crystal compound differs in the thickness direction

[0343] In the third embodiment, as described later, a photosensitive compound whose polarity changes by light irradiation is used.

[0344] Hereinafter, the steps of each of the above steps will be described in detail.

[0345] <Step 1C>

[0346] Step 1C is a step of forming a composition layer containing a photosensitive compound whose polarity changes by light irradiation and a liquid crystal compound having a polymerizable group. By carrying out this step, a composition layer on which the light irradiation treatment described later is carried out can be formed.

[0347] The liquid crystal compound contained in the composition layer is as described in Step 1A.

[0348] Also, as described in Step 1A described above, the composition layer can contain other components.

[0349] (photosensitive compound whose polarity changes by light irradiation)

[0350] The composition layer of Step 1C contains a photosensitive compound whose polarity changes by light irradiation (hereinafter, also referred to as "specific photosensitive compound").

[0351] The photosensitive compound whose polarity changes by light irradiation is a compound whose polarity changes before and after light irradiation. As described later, if the composition layer containing this specific photosensitive compound is subjected to light irradiation of the process 1C, the polarity of the specific compound changes in the region of the composition layer on the air side, and thus when the process 4C is performed, the orientation direction of the liquid crystal compound tilts or is perpendicular to the layer surface with the change in the polarity thereof.

[0352] The change in the polarity of the specific photosensitive compound can be a change in hydrophilization or a change in hydrophobization. Of these, from the viewpoint of being able to easily form an orientation state of the liquid crystal compound in which the orientation direction of the liquid crystal compound tilts or is perpendicular to the layer surface, a change in hydrophilization is preferred.

[0353] As the specific photosensitive compound which is hydrophilized by light irradiation, a compound having a group which generates a hydrophilic group by light irradiation is preferred. The type of the hydrophilic group is not particularly limited, and can be any one of a cationic group, an anionic group, and a nonionic group, and more specifically, a carboxylic acid group, a sulfonic acid group, a phosphonic acid group, an amino group, an ammonium group, an amide group, a thiol group, and a hydroxyl group can be mentioned.

[0354] The specific photosensitive compound preferably has a fluorine atom or a silicon atom. In the case where the specific photosensitive compound has the above atom, the specific photosensitive compound is easily distributed unevenly in the vicinity of the surface of the composition layer, and thus an optical anisotropic layer desired is easily formed.

[0355] As the specific photosensitive compound, a compound represented by formula (X) is preferred.

[0356] [Chemical Formula 3]

[0357]

[0358] In the above formula (X),

[0359] T represents an n+m-valent aromatic hydrocarbon group,

[0360] Sp represents a single bond or a 2-valent linking group,

[0361] Hb represents a fluorine-substituted alkyl group having 4 to 30 carbon atoms,

[0362] m represents an integer of 1 to 4,

[0363] n represents an integer of 1 to 4,

[0364] A represents a group represented by the following formula (Y),

[0365] [Chemical Formula 4]

[0366]

[0367] In the formula (Y) above,

[0368] R1to R5independently represent a hydrogen atom or a monovalent substituent,

[0369] * indicates a bonding site.

[0370] In the formula (X) above, when a plurality of Sp, a plurality of Hb, or a plurality of A are present, respectively, the plurality of Sp, the plurality of Hb, or the plurality of A can be the same as or different from each other.

[0371] In the formula (X) above, T represents an n+m-valent aromatic hydrocarbon group.

[0372] The aromatic hydrocarbon group is not particularly limited as long as it is a group obtained by removing n+m hydrogen atoms from an aromatic hydrocarbon ring, but the number of carbon atoms is preferably 6 to 22, more preferably 6 to 14, and further preferably 6 to 10. The aromatic hydrocarbon group is particularly preferably a benzene ring.

[0373] In addition, the aromatic hydrocarbon group can have a substituent other than the group represented by -Sp-Hb and the group represented by -C(=O)O-A. As the substituent, for example, an alkyl group (for example, an alkyl group having 1 to 8 carbon atoms), an alkoxy group (for example, an alkoxy group having 1 to 8 carbon atoms), a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), a cyano group, and an acyloxy group (for example, an acetoxy group) can be given.

[0374] In the formula (X) above, Sp represents a single bond or a divalent linking group, and is preferably a divalent linking group.

[0375] The divalent linking group is not particularly limited, but is preferably a linking group selected from the group consisting of a linear or branched alkylene group (preferably, an alkylene group having 1 to 20 carbon atoms, more preferably, an alkylene group having 1 to 10 carbon atoms, and further preferably, an alkylene group having 1 to 6 carbon atoms), a linear or branched alkenylene group (preferably, an alkenylene group having 2 to 20 carbon atoms, more preferably, an alkenylene group having 2 to 10 carbon atoms, and further preferably, an alkenylene group having 2 to 6 carbon atoms), a linear or branched alkynylene group (preferably, an alkynylene group having 2 to 20 carbon atoms, more preferably, an alkynylene group having 2 to 10 carbon atoms, and further preferably, an alkynylene group having 2 to 6 carbon atoms), or a group in which one or two or more -CH2- of these is substituted with a "divalent organic group" described below.

[0376] Among the divalent linking groups, from the viewpoint of further improving solubility, an alkylene group having 1 to 10 carbon atoms in which one or two or more -CH2- is substituted with a "divalent organic group" described below is preferable.

[0377] (2-valent organic group)

[0378] As the 2-valent organic group, -0-, -S-, -C(=0)-, -C(=0)0-, -OC(=0)-, -C(=0)S-, -SC(=0)-, -NR6C(=0)-, or -C(=0)NR6- can be given. Among the above, from the viewpoint of further hydrophilization, -0-, -S-, -C(=0)-, -C(=0)0-, -OC(=0)-, -C(=0)S-, or SC(=0)- is more preferable, -0-, -C(=0)-, -C(=0)0-, or OC(=0)- is further preferable, and -0-, -C(=0)0-, or OC(=0)- is particularly preferable.

[0379] Further, the above R6 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

[0380] In addition, in the case where the above 2-valent linking group contains the above 2-valent organic group, it is preferable that the above 2-valent organic groups are not adjacent to each other.

[0381] In the above formula (X), Hb represents a fluorine-substituted alkyl group having 4 to 30 carbon atoms.

[0382] Hb is preferably an alkyl group having 4 to 20 carbon atoms, and more preferably an alkyl group having 4 to 10 carbon atoms. Among them, the fluorine-substituted alkyl group can be a perfluoroalkyl group in which all of the hydrogen atoms are substituted with fluorine atoms, or a fluoroalkyl group in which a part of the hydrogen atoms are substituted with fluorine atoms. Further, the fluorine-substituted alkyl group can be any one of a chain, a branched chain, and a cyclic, but is preferably a chain or a branched chain, and more preferably a chain.

[0383] As the fluorine-substituted alkyl group, a structure of a perfluoroalkyl group is preferable.

[0384] In the above formula (X), preferable modes of the group represented by -Sp-Hb are exemplified below.

[0385] Further, in the following examples, * indicates the connection position with T.

[0386] (C p F 2p+1 )-(CH2) q -O-(CH2) r -O-*

[0387] (C p F 2p+1 )-(CH2) q -C(=0)0-(CH2) r -C(=0)O-*

[0388] (C p F2p+1 -(CH2) q -OC(=O)-(CH2) r -C(=O)O-

[0389] (C p F 2p+1 )-(CH2) q -OC(=O)-(CH2) r -OC(=O)-

[0390] In the group represented by -Sp-Hb, p is preferably 4 to 30, more preferably 4 to 20, and further preferably 4 to 10. q is preferably 0 to 6, more preferably 0 to 4, and further preferably 0 to 3. r is preferably 1 to 6, more preferably 1 to 4, and further preferably 1 to 3.

[0391] Further, the total number of carbon atoms in the moiety other than the perfluoro group is preferably 10 or less.

[0392] In the above formula (X), n and m each independently represent an integer of 1 to 4.

[0393] From the viewpoint of further proceeding with hydrophilization, n is preferably 2 or more. m is preferably 1 to 3, and more preferably 2.

[0394] In the above formula (X), A represents a group represented by the above formula (Y).

[0395] Hereinafter, formula (Y) will be described.

[0396] In the above formula (Y), R1to R5each independently represent a hydrogen atom or a monovalent substituent. The monovalent substituent represented by R1to R5is not particularly limited.

[0397] As the monovalent substituent represented by R1to R4, for example, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), a hydroxyl group, a cyano group, a substituted or unsubstituted amino group (represented by -N(R A )2, 2 R A each independently represent a hydrogen atom or a monovalent organic group (as the monovalent organic group, for example, an alkyl group having 1 to 5 carbon atoms), an alkoxy group having 1 to 8 carbon atoms (for example, a methoxy group and an ethoxy group), an amido group having 2 to 8 carbon atoms (for example, -N(R B )C(=O)R C (R B represents a hydrogen atom or a monovalent organic group (as the monovalent organic group, for example, an alkyl group having 1 to 5 carbon atoms), and R Crepresents a monovalent organic group (as a monovalent organic group, for example, an alkyl group having 1 to 5 carbon atoms) or -C(=O)N(R D )2 (two R D each independently represent a hydrogen atom or a monovalent organic group (for example, an alkyl group having 1 to 5 carbon atoms).), an alkoxycarbonyl group having 2 to 8 carbon atoms (for example, -C(=O)OCH3), an acyloxy group having 2 to 8 carbon atoms (for example, -OC(=O)CH3), and -Sp A -Hb A .

[0398] The above Sp A and the above Hb A have the same meanings as those of Sp and Hb of the above formula (X), respectively, and the preferable modes thereof are also the same. In addition, in formula (Y), in the case where a plurality of R1to R4represent -Sp A -Hb A , the plurality of Sp A each other and the plurality of Hb A each other can be the same or different.

[0399] where, as the above R1to R4, it is preferable that each independently be a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, an alkoxy group, -NH2, -NH(CH3), -N(CH3)2, -C(=O)OCH3, -OC(=O)CH3, -NHC(=O)CH3, -N(CH3)C(=O)CH3, or -Sp A -Hb A .

[0400] In particular, from the viewpoint of further accelerating the decomposition speed of the compound represented by formula (X) based on exposure and further hydrophilizing and / or the viewpoint of further improving the orientation, it is more preferable that the above R1to R4each independently be -OCH3or -Sp A -Hb A . In the case of -OCH3, there is a tendency that an ether oxygen is included in its structure (in particular, the position bonded to the benzene ring in formula (Y) is an ether oxygen), and thus the decomposition speed of the compound represented by formula (X) based on exposure is further accelerated and further hydrophilization is performed. On the other hand, in the case of -Sp A -Hb A , there is a tendency that the orientation is further improved by the presence of Hb A . In addition, in the case where Sp A includes an ether oxygen in its structure (in particular, the position bonded to Hb A in Sp AWhen the end of the side opposite to the bonded side (in other words, the end of the side connected to the benzene ring of formula (Y)) contains an ether oxygen, the effect of accelerating the decomposition rate can be obtained in the same way as the -OCH3 above.

[0401] Furthermore, from the viewpoint of further accelerating the decomposition rate of the compound represented by formula (X) based on exposure and thus further hydrophilicating it, it is preferable that at least two of the above R1 to R4 are independently -OCH3 or Sp. B -Hb B More preferably, R2 and R3 are independently -OCH3 or Sp B -Hb B .

[0402] Among them, Sp B This indicates an alkylene group with 1 to 10 carbon atoms substituted with -O-. Wherein, as described above, in Sp... B In and Hb B When the end of the side opposite to the bonded side (in other words, the end of the side connected to the benzene ring of formula (Y)) contains an ether oxygen, the effect of accelerating the decomposition rate is more significant, and further hydrophilization occurs. Furthermore, when the -CH2- in the aforementioned alkylene group is substituted with multiple -O-, it is preferable that the -O- groups are not adjacent to each other. The aforementioned alkylene group is more preferably composed of 1 to 7 carbon atoms, more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms. Moreover, the alkylene group can be either straight-chain or branched, but straight-chain is preferred.

[0403] The above Hb B This refers to fluorinated alkyl groups with 4 to 30 carbon atoms. Regarding the above Hb... B The preferred method is the same as Hb in the above formula (X).

[0404] In addition, in equation (Y), there are multiple representations of -Sp in R1 to R4. B -Hb B In the case where there are multiple Sp B Hb and the existence of multiple Hb B They can be the same or different.

[0405] From the viewpoint of further accelerating the decomposition rate of the compound represented by the exposure-based formula (X) to further hydrophilize it and further improve its orientation, it is preferable that at least two of the above R1 to R4 are -Sp. B -Hb B More preferably, both R2 and R3 are -Sp B -Hb B In particular, as mentioned above -Sp B -Hb B, preferably a structure represented by the following formula (Z).

[0406] Formula (Z) (C p F 2p+1 )-(CH2) q -O-(CH2) r -O-*

[0407] In formula (Z), p is preferably 4 to 30, more preferably 4 to 20, and further preferably 4 to 10. q is preferably 0 to 5, more preferably 0 to 4, and further preferably 0 to 3. r is preferably 1 to 5, more preferably 1 to 4, and further preferably 1 to 3.

[0408] In formula (Y), R5is preferably a hydrogen atom, a methyl group, an ethyl group, or an aromatic group.

[0409] The aromatic group is not particularly limited, but is preferably a phenyl group having 6 to 14 carbon atoms, more preferably 6 to 10 carbon atoms, and further preferably a phenyl group.

[0410] From the viewpoint of further accelerating the decomposition rate of the compound represented by formula (X) based on exposure, R5is preferably a methyl group, an ethyl group, or an aromatic group, more preferably an ethyl group or an aromatic group, and further preferably an aromatic group.

[0411] In formula (Y), * indicates a bonding site with C(=O)O- in formula (X).

[0412] The compound represented by formula (X) can be a compound having symmetry in the molecular structure, or a compound having no symmetry. The symmetry described herein indicates any one of point symmetry, line symmetry, and rotational symmetry, and the asymmetry indicates none of point symmetry, line symmetry, and rotational symmetry.

[0413] In the case where a plurality of Sp, Hb, or A are present in the compound represented by formula (X), respectively, the plurality of Sp, the plurality of Hb, or the plurality of A can be the same or different, respectively.

[0414] The content of the specific photosensitive compound in the composition layer can be appropriately set according to the characteristics (for example, retardation or wavelength dispersion) of the optical anisotropic layer to be formed.

[0415] The content of the specific photosensitive compound is preferably 0.01 to 10% by mass, and more preferably 0.05 to 5% by mass, with respect to the total mass of the liquid crystal compound, from the viewpoint of more easily forming an optical anisotropic layer having a predetermined structure.

[0416] The composition layer containing the above-described components is formed in the process 1A, but the step is not particularly limited. For example, a method in which a composition containing the above-described specific photosensitive compound and the liquid crystal compound having a polymerizable group is coated on a substrate, and a drying treatment is performed as necessary (hereinafter, also referred to simply as "coating method") and a method in which a composition layer is formed to be transferred on a substrate can be given. Among them, from the viewpoint of productivity, the coating method is preferred.

[0417] Hereinafter, the coating method will be described in detail.

[0418] The composition used in the coating method contains the above-described specific photosensitive compound, the liquid crystal compound having a polymerizable group, and other components (for example, a polymerization initiator, a polymerizable monomer, a surfactant, and a polymer) used as necessary in addition thereto.

[0419] The content of each component in the composition is preferably adjusted to the content of each component in the above-described composition layer.

[0420] The coating method is not particularly limited, and for example, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, and a die coating method can be given.

[0421] In addition, after the composition is coated, a treatment of drying the coating film coated on the substrate can be performed as necessary. By performing the drying treatment, the solvent can be removed from the coating film.

[0422] The film thickness of the coating film is not particularly limited, but is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, and further preferably 0.5 to 10 μm.

[0423] <Process 2C>

[0424] The process 2C is a process in which a heating treatment is performed on the composition layer to orient the liquid crystal compound in the composition layer. By performing this process, the liquid crystal compound in the composition layer becomes in a predetermined orientation state. In addition, as described later Figure 11 For example, by performing the process 2C, the liquid crystal compound is uniformly oriented in the composition.

[0425] As the conditions of the heating treatment, the optimum conditions are selected according to the liquid crystal compound used.

[0426] Among them, as the heating temperature, the case of 25 to 250°C is more common, the case of 40 to 150°C is more common, and the case of 50 to 130°C is further more common.

[0427] As the heating time, the case of 0.1 to 60 minutes is more common, and the case of 0.2 to 5 minutes is more common.

[0428] <Process 3C>

[0429] Process 3C is a process of performing light irradiation on the composition layer under conditions in which the oxygen concentration is 1% by volume or more after Process 2C at 300 mJ / cm 2 The following light irradiation is performed for 50 seconds or less. The following describes the mechanism of the present process using the drawings. Hereinafter, the case in which the composition layer contains a compound that is hydrophilized by light irradiation is described as an example. In Figure 11 In Process 3C, the liquid crystal compound LC is uniformly oriented in the composition layer.

[0430] As shown in Figure 11 Process 3C, light irradiation is performed from the side of the substrate 10 opposite the side of the composition layer 320 (the direction of the hollow arrow in Figure 11 ). In addition, in Figure 11 Process 3C, light irradiation is performed from the side of the substrate 10, but can also be performed from the side of the composition layer 320.

[0431] At this time, if the lower region 320A on the side of the substrate 10 and the upper region 320B on the side opposite the side of the substrate 10 of the composition layer 320 are compared, the surface of the upper region 320B is on the air side, and thus the oxygen concentration in the upper region 320B is high, and the oxygen concentration in the lower region 320A is low. Therefore, if light irradiation is performed on the composition layer 320, polymerization of the liquid crystal compound is easily performed in the lower region 320A, and the orientation state of the liquid crystal compound is fixed. In addition, a specific photosensitive compound is also present in the lower region 320A, and the specific photosensitive compound is also photosensitive and is hydrophilized. However, since the orientation state of the liquid crystal compound is fixed in the lower region 320A, even if Process 4C, which is described later, in which a heat treatment is performed on the composition layer that has been subjected to light irradiation, is performed, a change in the orientation state of the liquid crystal compound does not occur.

[0432] Furthermore, since the oxygen concentration is high in the upper region 320B, even if light irradiation is performed, polymerization of the liquid crystal compound is hindered by the oxygen and is difficult to perform. Also, a specific photosensitive compound is present in the upper region 320B, and thus the specific photosensitive compound is photosensitive and is hydrophilized. Therefore, if Process 4C, which is described later, is performed, the orientation state of the liquid crystal compound is changed by the influence of the polarity that changes.

[0433] That is, by performing Process 3C, fixation of the orientation state of the liquid crystal compound is easily performed in the region on the side of the substrate (the lower region) of the composition layer. Furthermore, fixation of the orientation state of the liquid crystal compound is difficult to perform in the region on the side opposite the side of the substrate (the upper region) of the composition layer, and becomes a state in which the polarity changes depending on the specific photosensitive compound that is photosensitive.

[0434] The various conditions (oxygen concentration, irradiation time, irradiation amount, etc.) of the light irradiation in Step 3C are the same as those of the light irradiation in Step 3A.

[0435] <Step 4C>

[0436] Step 4C is a step of performing a heat treatment on the composition layer at a higher temperature than the light irradiation after Step 3C. By performing this step, in the region in which the polarity is changed by the specific photosensitive compound in the composition layer on which the light irradiation has been performed, the alignment state of the liquid crystal compound is changed. More specifically, this step is a step of performing a heat treatment on the composition layer after Step 3C at a higher temperature than the irradiation to align the liquid crystal compound in the composition layer which is not fixed in Step 3C.

[0437] Hereinafter, the mechanism of this step is described using the drawings.

[0438] As described above, if Step 3C is performed on the composition layer 320 shown in Figure 11 , the alignment state of the liquid crystal compound is fixed in the lower region 320A and it is difficult to perform the polymerization of the liquid crystal compound in the upper region 320B, and the alignment state of the liquid crystal compound is not fixed. Also, in the upper region 320B, the specific photosensitive compound is photosensitive and is hydrophilized. If such a change in polarity occurs, the alignment direction of the liquid crystal compound in the upper region 320B is affected in comparison with the state before the light irradiation. This point is described in more detail. Also, as described above, hereinafter, the case in which the composition layer contains the specific photosensitive compound which is hydrophilized by the light irradiation is described as an example.

[0439] In the case in which the composition layer contains the specific photosensitive compound which is hydrophilized by the light irradiation, as shown in Figure 12 , if Step 4C is performed, the liquid crystal compound is homeotropically aligned in the upper region 320B. In particular, in the case in which the specific photosensitive compound is present in the vicinity of the surface of the composition layer, the liquid crystal compound is easily homeotropically aligned.

[0440] On the other hand, as described above, in the lower region 320A of the composition layer 320, the polymerization of the liquid crystal compound is performed at the time of Step 3C and the alignment state of the liquid crystal compound is fixed, and thus the re-alignment of the liquid crystal compound is not performed.

[0441] As described above, by performing Step 4C, it is possible to form a region containing the liquid crystal compound which is inclined with respect to the surface of the layer or is homeotropically aligned.

[0442] Also, in the above Figure 11In the present embodiment, the manner of vertical alignment of the liquid crystal compound is described, but the present embodiment is not limited to this manner. For example, a manner of inclined alignment of the liquid crystal compound can be adopted.

[0443] The heat treatment is performed at a higher temperature than the light irradiation.

[0444] The difference between the temperature of the heat treatment and the temperature of the light irradiation is preferably 5°C or higher, more preferably 10 to 110°C, and even more preferably 20 to 110°C.

[0445] The temperature of the heat treatment is preferably higher than the temperature of the light irradiation and is a temperature at which the liquid crystal compound in the composition layer is aligned, and more specifically, the temperature is often 40 to 250°C, more often 50 to 150°C, even more often more than 50°C and 150°C or lower, and particularly often 60 to 130°C.

[0446] As the heating time, the time is often 0.01 to 60 minutes, and more often 0.03 to 5 minutes.

[0447] <Process 5C>

[0448] Process 5C is a process in which, after Process 4C, a curing treatment is performed on the composition layer to form an optically anisotropic layer having a plurality of regions in which the alignment state of the liquid crystal compound differs in the thickness direction. By performing this process, the alignment state of the liquid crystal compound in the composition layer is fixed, and as a result, a prescribed optically anisotropic layer can be formed. In addition, by performing this process, an optically anisotropic layer having a plurality of regions in which the tilt angle of the alignment direction of the liquid crystal compound with respect to the surface of the layer differs in the thickness direction can be formed. In particular, by performing this process, an optically anisotropic layer having a region in which the alignment state of the liquid crystal compound is fixed to homeotropic alignment or inclined alignment and a region in which the alignment state of the liquid crystal compound is fixed to horizontal alignment (uniform alignment) in the thickness direction can be formed.

[0449] As the method of the curing treatment in Process 5C, the method of the curing treatment in Process 5A can be cited.

[0450] The thickness of the optically anisotropic layer is not particularly limited, but is preferably 0.05 to 10 μm, more preferably 0.1 to 8.0 μm, and even more preferably 0.2 to 6.0 μm.

[0451] The optical properties in the optically anisotropic layer in the third embodiment are not particularly limited, and the optimum values are selected depending on the use. Hereinafter, as an example, the case of the optically anisotropic layer prepared by the above-mentioned steps, which has a first region in which the alignment state of the perpendicularly aligned liquid crystal compound is fixed and a second region in which the alignment state of the uniformly aligned liquid crystal compound is fixed along the thickness direction, is described in detail.

[0452] In the case where the thickness of the first region of the above-mentioned optically anisotropic layer is set to dl and the in-plane refractive index anisotropy of the first region measured at a wavelength of 550 nm is set to Δnl, the first region preferably satisfies the following formula (1C-1) from the viewpoint that the optically anisotropic layer can be preferably applied to a circular polarizing plate and the viewpoint that the light leakage in the oblique direction can be reduced when used as an optical compensation plate for a liquid crystal display device.

[0453] Formula (1C-1) 0 nm < Δnl dl < 30 nm

[0454] Further, the formula (1C-2) is more preferably satisfied.

[0455] Formula (1C-2) 0 nm < Δnl dl < 20 nm

[0456] The thickness-direction retardation of the first region of the optically anisotropic layer at a wavelength of 550 nm is preferably -150 to -20 nm, and more preferably -120 to -20 nm.

[0457] Further, in the case where the thickness of the second region of the above-mentioned optically anisotropic layer is set to d2 and the in-plane refractive index anisotropy of the second region measured at a wavelength of 550 nm is set to Δn2, the second region preferably satisfies the following formula (2C-1) from the viewpoint that the optically anisotropic layer can be preferably applied to a circular polarizing plate or the viewpoint that the optically anisotropic layer can be preferably applied to an optical compensation plate for a liquid crystal display device. That is, the in-plane retardation of the second region at a wavelength of 550 nm is preferably 100 to 180 nm.

[0458] Formula (2C-1) 100 nm < Δn2 d2 < 180 nm

[0459] Further, the formula (2C-2) is more preferably satisfied.

[0460] Formula (2C-2) 110 nm < Δn2 d2 < 170 nm

[0461] Further, the refractive index anisotropy Δn2 indicates the refractive index anisotropy of the first region.

[0462] The optically anisotropic layer in the third embodiment preferably exhibits inverse wavelength dispersion.

[0463] That is, the in-plane retardation of the optically anisotropic layer measured at a wavelength of 450 nm, Re(450), the in-plane retardation of the optically anisotropic layer measured at a wavelength of 550 nm, Re(550), and the in-plane retardation of the optically anisotropic layer measured at a wavelength of 650 nm, Re(650), preferably satisfy the relationship of Re(450)≤Re(550)≤Re(650).

[0464] The optical properties of the optically anisotropic layer in the third embodiment are not particularly limited, but preferably function as a λ / 4 plate or function as an optical compensation plate for a liquid crystal display device.

[0465] A λ / 4 plate is a plate having a function of converting linearly polarized light of a certain specific wavelength into circularly polarized light (or converting circularly polarized light into linearly polarized light), and refers to a plate (optically anisotropic layer) in which the in-plane retardation Re(λ) at a specific wavelength λ nm satisfies Re(λ) = λ / 4.

[0466] This formula is satisfied at any wavelength (e.g., 550 nm) in the visible light region, but preferably the in-plane retardation Re(550) at a wavelength of 550 nm satisfies the relationship of 100 nm≤Re(550)≤180 nm.

[0467] <<Fourth Embodiment>>

[0468] The fourth embodiment of the method for producing an optically anisotropic layer of the present application includes the following steps 1D to 5D. As described later, in the fourth embodiment, an optically anisotropic layer having a region in which the orientation state (e.g., a horizontal orientation state) in which a liquid crystal compound is oriented is fixed in the thickness direction and a region in which the state in which the liquid crystal compound is not oriented (isotropic phase of the liquid crystal compound) is fixed is formed.

[0469] Step 1D: a step of forming a composition layer containing a liquid crystal compound having a polymerizable group

[0470] Step 2D: a step of subjecting the composition layer to a heat treatment to orient the liquid crystal compound in the composition layer

[0471] Step 3D: after Step 2D, a step of subjecting the composition layer to light irradiation at an oxygen concentration of 1% by volume or more at 300 mJ / cm 2 a step of performing light irradiation for 50 seconds or less

[0472] Step 4D: after Step 3D, a step of subjecting the composition layer to a heat treatment at a temperature higher than the light irradiation time and at a temperature at which the liquid crystal compound becomes an isotropic phase

[0473] Process 5D: A process of performing a curing treatment on the composition layer after process 4D to form an optically anisotropic layer having a plurality of regions different in orientation state of the liquid crystal compound in the thickness direction

[0474] Hereinafter, the steps of each of the above processes will be described in detail.

[0475] <Process 1D>

[0476] Process 1D is a process of forming a composition layer containing a liquid crystal compound having a polymerizable group. By performing this process, a composition layer on which a light irradiation treatment described later is performed can be formed.

[0477] The liquid crystal compound contained in the composition layer is as described in process 1A.

[0478] Also, as described in process 1A described above, the composition layer can contain other components other than the liquid crystal compound.

[0479] The composition layer containing the above components is formed in process 1A, but the steps thereof are not particularly limited. For example, a method in which a composition containing the above liquid crystal compound having a polymerizable group is coated on a substrate, and a drying treatment is performed as necessary (hereinafter, also referred to simply as "coating method") and a method in which a composition layer is formed to be transferred to a substrate can be given. Among them, from the viewpoint of productivity, the coating method is preferred.

[0480] Hereinafter, the coating method will be described in detail.

[0481] The composition used in the coating method contains the above liquid crystal compound having a polymerizable group and other components (for example, a polymerization initiator, a polymerizable monomer, a surfactant, and a polymer) used as necessary in addition thereto.

[0482] The content of each component in the composition is preferably adjusted to the content of each component in the above composition layer.

[0483] The coating method is not particularly limited, and for example, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, and a die coating method can be given.

[0484] In addition, as necessary, after the composition is coated, a treatment of drying the coating film coated on the substrate can be performed. By performing the drying treatment, it is possible to remove the solvent from the coating film.

[0485] The film thickness of the coating film is not particularly limited, but is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, and further preferably 0.5 to 10 μm.

[0486] <Process 2D>

[0487] Process 2D is a process of performing a heat treatment on the composition layer to orient the liquid crystal compound in the composition layer. By performing this process, the liquid crystal compound in the composition layer becomes in a prescribed orientation state. In addition, as will be described later Figure 13 For example, by performing process 2D, the liquid crystal compound is uniformly oriented in the composition.

[0488] As the conditions of the heat treatment, the optimum conditions are selected depending on the liquid crystal compound used.

[0489] Among them, the case where the heating temperature is 25 to 250°C is more common, the case where it is 40 to 150°C is more common, and the case where it is 50 to 130°C is further more common.

[0490] As the heating time, the case where it is 0.1 to 60 minutes is more common, and the case where it is 0.2 to 5 minutes is more common.

[0491] <Process 3D>

[0492] Process 3D is a process of, after process 2D, performing light irradiation on the composition layer in a direction opposite to the side of the composition layer 420 of the substrate 10 (the direction of the hollow arrow in 2 The light irradiation is performed for 50 seconds or less. Hereinafter, the mechanism of this process will be described using the drawings. In Figure 13 , the liquid crystal compound LC is uniformly oriented in the composition layer.

[0493] As Figure 13 indicated in process 3D, the light irradiation is performed in a direction opposite to the side of the composition layer 420 of the substrate 10 (the direction of the hollow arrow in Figure 13 ). In addition, in Figure 13 , the light irradiation is performed from the side of the substrate 10, but it can be performed from the side of the composition layer 420.

[0494] At this time, if the lower region 420A on the side of the substrate 10 and the upper region 420B on the side opposite to the side of the substrate 10 of the composition layer 420 are compared, the surface of the upper region 420B is on the air side, and thus the oxygen concentration in the upper region 420B is high, and the oxygen concentration in the lower region 420A is low. Therefore, if the composition layer 420 is subjected to the light irradiation, the polymerization of the liquid crystal compound is easily performed in the lower region 420A, and the orientation state of the liquid crystal compound is fixed. Therefore, even if process 4D, which will be described later, of performing a heat treatment on the composition layer subjected to the light irradiation is performed, the change in the orientation state of the liquid crystal compound does not occur.

[0495] Further, since the oxygen concentration in the upper region 420B is high, even if the light irradiation is performed, the polymerization of the liquid crystal compound is hindered by the oxygen and is difficult to be performed. Therefore, if process 4D, which will be described later, is performed, the orientation state of the liquid crystal compound changes.

[0496] That is, by carrying out the process 3D, the fixing of the alignment state of the liquid crystal compound is easily performed in the region on the substrate side (lower side region) of the composition layer. Also, the fixing of the alignment state of the liquid crystal compound is difficult to perform in the region on the side opposite to the substrate side (upper side region) of the composition layer, and becomes a state in which the alignment state of the liquid crystal compound is changed by the process 4D described later.

[0497] The various conditions (oxygen concentration, irradiation time, irradiation amount, etc.) of the light irradiation in the process 3D are the same as those of the light irradiation in the process 3A described above.

[0498] <Process 4D>

[0499] The process 4D is a process in which, after the process 3D, a heating treatment is carried out on the composition layer at a temperature higher than that at the time of light irradiation and at a temperature at which the liquid crystal compound becomes an isotropic phase. By carrying out this process, in the upper side region in which the alignment state of the liquid crystal compound in the composition layer is not fixed, the liquid crystal compound exhibits an isotropic phase.

[0500] Hereinafter, the mechanism of this process will be described using the drawings.

[0501] As described above, if the process 3D is carried out on the composition layer 420 shown in FIG. 4B, the alignment state of the liquid crystal compound is fixed in the lower side region 420A and it is difficult to perform the polymerization of the liquid crystal compound in the upper side region 420B, and the alignment state of the liquid crystal compound is not fixed. Figure 13 Therefore, if the process 4D is carried out, as shown in FIG. 4D, the polymerization of the liquid crystal compound is not performed in the upper side region 420B, and thus the alignment state of the liquid crystal compound is destroyed and becomes an isotropic phase.

[0502] Figure 14 On the other hand, as described above, in the lower side region 420A of the composition layer 420, the polymerization of the liquid crystal compound is performed at the time of the process 3D and the alignment state of the liquid crystal compound is fixed, and thus the re-alignment of the liquid crystal compound is not performed.

[0503] As described above, by carrying out the process 4D, it is possible to form an optically anisotropic layer having a region in which the alignment state (for example, a horizontal alignment state) of the liquid crystal compound is fixed and a region in which the state in which the liquid crystal compound is not aligned (an isotropic phase of the liquid crystal compound) is fixed along the thickness direction.

[0504] The heating treatment is carried out at a temperature higher than that at the time of light irradiation and at a temperature at which the liquid crystal compound becomes an isotropic phase.

[0505] The heating treatment is carried out at a temperature higher than that at the time of light irradiation and at a temperature at which the liquid crystal compound becomes an isotropic phase.

[0506] ​The difference between the temperature of the heating treatment and the temperature at the time of light irradiation is preferably 5°C or more, more preferably 10 to 110°C, and even more preferably 20 to 110°C.

[0507] The temperature of the heating treatment is preferably higher than the temperature at the time of light irradiation and is a temperature at which the liquid crystal compound that has not been fixed in the composition layer is set to an isotropic phase, and more specifically, the temperature is often 40 to 250°C, more often 50 to 150°C, even more often more than 50°C and 150°C or lower, and especially often 60 to 130°C.

[0508] The heating time is often 0.01 to 60 minutes, and more often 0.03 to 5 minutes.

[0509] <Process 5D>

[0510] Process 5D is a process in which, after Process 4D, a curing treatment is performed on the composition layer to form an optically anisotropic layer having a plurality of regions in which the orientation state of the liquid crystal compound differs in the thickness direction. By performing this process, the orientation state of the liquid crystal compound in the composition layer is fixed, and as a result, a prescribed optically anisotropic layer can be formed.

[0511] As the method of the curing treatment in Process 5D, the method of the curing treatment in Process 5A can be cited.

[0512] The thickness of the optically anisotropic layer is not particularly limited, but is preferably 0.05 to 10 μm, more preferably 0.1 to 8.0 μm, and even more preferably 0.2 to 6.0 μm.

[0513] In addition, in the above Figure 13 and Figure 14 , the manner of the optically anisotropic layer having regions in which the orientation state of the horizontally oriented liquid crystal compound is fixed and regions in which the liquid crystal compound is in an isotropic phase is described, but as long as the regions in which the liquid crystal compound is in an isotropic phase are included, the manner is not limited to this.

[0514] For example, as the orientation state of the liquid crystal compound, in the case of a rod-shaped liquid crystal compound, as the orientation state thereof, for example, nematic orientation (a state in which a nematic phase is formed), smectic orientation (a state in which a smectic phase is formed), cholesteric orientation (a state in which a cholesteric phase is formed), and mixed orientation can be cited. In the case of a discotic liquid crystal compound, as the orientation state thereof, nematic orientation, columnar orientation (a state in which a columnar phase is formed), and cholesteric orientation can be cited.

[0515] More specifically, an optically anisotropic layer having a region in the thickness direction in which the alignment state of the vertically aligned liquid crystal compound is fixed and a region in which the state in which the liquid crystal compound exhibits an isotropic phase is fixed can be formed. Also, an optically anisotropic layer formed using a liquid crystal compound and having a region in the thickness direction in which a cholesteric liquid crystal phase is fixed and a region in which the state in which the liquid crystal compound exhibits an isotropic phase is fixed can be formed.

[0516] The optical properties of the optically anisotropic layer in the fourth embodiment are not particularly limited, but preferably function as a λ / 4 plate.

[0517] A λ / 4 plate is a plate having a function of converting linearly polarized light of a certain specific wavelength into circularly polarized light (or converting circularly polarized light into linearly polarized light), and refers to a plate (optically anisotropic layer) in which the in-plane retardation Re(λ) at a specific wavelength λ nm satisfies Re(λ) = λ / 4.

[0518] This formula is satisfied at any wavelength (for example, 550 nm) in the visible region, but preferably the in-plane retardation Re(550) at a wavelength of 550 nm satisfies the relationship 110 nm ≤ Re(550) ≤ 180 nm.

[0519] <Usage>

[0520] The optically anisotropic layer can be combined with various components.

[0521] For example, the above-described optically anisotropic layer can be combined with another optically anisotropic layer. That is, as shown in Figure 15 a laminate 24 including a substrate 10, the optically anisotropic layer 20 manufactured by the above-described manufacturing method, and another optically anisotropic layer 22 can be manufactured. In addition, the laminate 24 described in Figure 15 The laminate 24 described in the above includes a substrate 10, but a substrate can not be included in the laminate.

[0522] The other optically anisotropic layer is not particularly limited, and for example, an A plate (positive A plate and negative A plate) and a C plate (positive C plate and negative C plate) can be given. Among these, from the viewpoint of being easily applicable to the various uses described later (for example, a circularly polarizing plate), a C plate is preferable.

[0523] The absolute value of the retardation in the thickness direction at a wavelength of 550 nm of the C plate is not particularly limited in the range, but is preferably 5 to 300 nm, and more preferably 10 to 200 nm.

[0524] In addition, in the present specification, an A plate and a C plate are defined as follows.

[0525] The A plate has two types of positive A plate (positive A plate) and negative A plate (negative A plate), and when the refractive index in the slow axis direction in the film surface (the direction in which the refractive index in the plane is the largest) is set as nx, the refractive index in the direction orthogonal to the slow axis in the plane is set as ny, and the refractive index in the thickness direction is set as nz, the positive A plate satisfies the relationship of formula (A1), and the negative A plate satisfies the relationship of formula (A2). In addition, Rth of the positive A plate represents a positive value, and Rth of the negative A plate represents a negative value.

[0526] Formula (A1) nx > ny ≈ nz

[0527] Formula (A2) ny < nx ≈ nz

[0528] In addition, the above "≈" includes not only the case where both are exactly the same, but also the case where both are actually the same. By "actually the same", for example, the case where (ny-nz) x d (where d is the thickness of the film) is -10 to 10 nm, preferably -5 to 5 nm, is also included in "ny ≈ nz", and the case where (nx-nz) x d is -10 to 10 nm, preferably -5 to 5 nm, is also included in "nx ≈ nz".

[0529] The C plate has two types of positive C plate (positive C plate) and negative C plate (negative C plate), and the positive C plate satisfies the relationship of formula (C1), and the negative C plate satisfies the relationship of formula (C2). In addition, Rth of the positive C plate represents a negative value, and Rth of the negative C plate represents a positive value.

[0530] Formula (C1) nz > nx ≈ ny

[0531] Formula (C2) nz < nx ≈ ny

[0532] In addition, the above "≈" includes not only the case where both are exactly the same, but also the case where both are actually the same. By "actually the same", for example, the case where (nx-ny) x d (where d is the thickness of the film) is 0 to 10 nm, preferably 0 to 5 nm, is also included in "nx ≈ ny".

[0533] The method for manufacturing the above-described laminate is not particularly limited, and known methods can be mentioned. For example, a method in which the optically anisotropic layer obtained by the manufacturing method of the present application is laminated with another optically anisotropic layer (for example, a C plate) to obtain a laminate can be mentioned. As the method for lamination, the other optically anisotropic layer can be attached to the optically anisotropic layer obtained by the manufacturing method of the present application, or the other optically anisotropic layer can be formed by applying a composition for forming the other optically anisotropic layer on the optically anisotropic layer obtained by the manufacturing method of the present application.

[0534] Further, the optically anisotropic layer obtained by the production method of the present application can be combined with a polarizer. That is, as shown in Figure 16 a polarizer-equipped optically anisotropic layer 28 including a substrate 10, the optically anisotropic layer 20 produced by the above production method, and a polarizer 26 can be produced. In Figure 16 the substrate 10 is provided with the polarizer 26, but it is not limited to this mode, and the polarizer 26 can be provided on the optically anisotropic layer 20.

[0535] Further, the polarizer-equipped optically anisotropic layer 28 described in the above includes the substrate 10, but the substrate can not be included in the polarizer-equipped optically anisotropic layer. Figure 16 The positional relationship when the optically anisotropic layer is laminated with the polarizer is not particularly limited, but in the case where the optically anisotropic layer has a first region in which the orientation state of the liquid crystal compound twisted around the helical axis extending in the thickness direction is fixed, and a second region in which the orientation state of the uniformly oriented liquid crystal compound is fixed, in the thickness direction, from the viewpoint that the optically anisotropic layer is preferably applicable to a circularly polarizing plate or the like, the absolute value of the angle formed by the in-plane slow axis of the second region and the absorption axis of the polarizer is preferably 5 to 25°, and more preferably 10 to 20°.

[0536] Further, in the case where the angle formed by the in-plane slow axis of the above second region and the absorption axis of the polarizer is negative, the twist angle of the liquid crystal compound in the first region is preferably also negative, and in the case where the angle formed by the in-plane slow axis of the above second region and the absorption axis of the polarizer is positive, the twist angle of the liquid crystal compound in the first region is preferably also positive.

[0537] In addition, in the case where the angle formed by the above in-plane slow axis and the polarizer is negative when viewed from the polarizer side, it indicates the case where the rotation angle of the in-plane slow axis is clockwise with the absorption axis of the polarizer as the reference, and in the case where the angle formed by the above in-plane slow axis and the polarizer is positive when viewed from the polarizer side, it indicates the case where the rotation angle of the in-plane slow axis is counterclockwise with the absorption axis of the polarizer as the reference.

[0538] Further, regarding the twist angle of the liquid crystal compound, it is indicated as negative when the orientation direction of the liquid crystal compound on the inner side is clockwise (right turn) with the orientation direction of the liquid crystal compound on the surface side (front side) as the reference, and it is indicated as positive when it is counterclockwise (left turn).

[0539] The polarizer can be any member having a function of converting natural light into a specific linearly polarized light, and for example, an absorption-type polarizer can be given.

[0540]

[0541] ​The type of polarizer is not particularly limited, and a generally used polarizer can be used, and examples thereof 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 are generally produced by adsorbing iodine or a dichroic dye on a polyvinyl alcohol and stretching the same.

[0542] In addition, a protective film can be provided on one or both sides of the polarizer.

[0543] The method for producing the optical anisotropic layer with a polarizer is not particularly limited, and a known method can be used. For example, a method in which the optical anisotropic layer obtained by the production method of the present application is laminated with a polarizer to obtain an optical anisotropic layer with a polarizer can be used.

[0544] In addition, although the manner in which the optical anisotropic layer is laminated with a polarizer is described above, in the present application, the laminate described above can be laminated with a polarizer to produce a laminate with a polarizer.

[0545] The optical anisotropic layer can be used for various applications. For example, the optical anisotropic layer can be preferably used for a circular polarizer, and the optical anisotropic layer with a polarizer described above can be used as a circular polarizer.

[0546] The circular polarizer having the above structure is preferably used for an antireflection application of an image display device such as a liquid crystal display device (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), and a cathode ray tube display device (CRT), and can improve the contrast ratio of display light.

[0547] For example, a method in which the circular polarizer of the present application is used on the light extraction surface side of an organic EL display device can be used. At this time, external light becomes linearly polarized light by the polarizing film, and then passes through the optical anisotropic layer to become circularly polarized light. When the circularly polarized light is reflected by a metal electrode, the state of the circularly polarized light is reversed, and when it passes through the optical anisotropic layer again, it becomes linearly polarized light that is inclined by 90° from the time of incidence to reach the polarizing film and is absorbed. As a result, the influence of external light can be suppressed.

[0548] The optical anisotropic layer with a polarizer or the laminate with a polarizer is preferably used for an organic EL display device. That is, the optical anisotropic layer with a polarizer or the laminate with a polarizer is preferably provided on an organic EL panel of an organic EL display device and is preferably used for an antireflection application.

[0549] An organic EL panel is a component that forms a light-emitting layer or multiple organic compound films, including a light-emitting layer, between a pair of electrodes, namely an anode and a cathode. In addition to the light-emitting layer, it may also have a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, and a protective layer, and each of these layers may have other functions. Various materials can be used to form each layer.

[0550] The optical anisotropic layer can also be preferably used as an optical compensation plate for a liquid crystal display device, and the aforementioned optical anisotropic layer with a polarizer can also be used as an optical compensation plate for a liquid crystal display device.

[0551] The liquid crystal cells used in the liquid crystal display device are preferably in VA (Vertical Alignment) mode, OCB (Optically Compensated Bend) mode, IPS (In-Plane-Switching) mode, FFS (Fringe-Field-Switching) mode or TN (Twisted Nematic) mode, but are not limited to these.

[0552] When the aforementioned optical anisotropy layer with a polarizer is used as an optical compensation plate in an IPS or FFS mode liquid crystal display device, it is preferable to use... Figure 12 As shown, the optical anisotropy layer has a region for fixing the orientation state of a uniformly oriented (horizontally oriented) liquid crystal compound and a region for fixing the orientation state of a vertically oriented (homeotropic alignment) liquid crystal compound. Preferably, the angle formed by the in-plane slow axis of the region for fixing the orientation state of the uniformly oriented (horizontally oriented) liquid crystal compound and the absorption axis of the polarizer is orthogonal or parallel. More preferably, the angle formed by the in-plane slow axis of the region for fixing the orientation state of the uniformly oriented (horizontally oriented) liquid crystal compound and the absorption axis of the polarizer is 0–5° or 85–95°.

[0553] Among them, the "in-plane slow axis" of the region formed by fixing the orientation state of the uniformly oriented (horizontally oriented) liquid crystal compound indicates the direction with the largest in-plane refractive index in the region formed by fixing the orientation state of the uniformly oriented (horizontally oriented) liquid crystal compound, and the "absorption axis" of the polarizer indicates the direction with the highest absorbance.

[0554] Further, in the case where the optical compensation sheet is used for a liquid crystal display device of an IPS mode or an FFS mode, it is preferable that the polarizer, the region in which the alignment state of the liquid crystal compound of the homeotropic alignment is fixed, the region in which the alignment state of the liquid crystal compound of the uniform alignment (horizontal alignment) is fixed, and the liquid cell are arranged in this order or the polarizer, the region in which the alignment state of the liquid crystal compound of the uniform alignment (horizontal alignment) is fixed, the region in which the alignment state of the liquid crystal compound of the homeotropic alignment is fixed, and the liquid cell are arranged in this order.

[0555] Example

[0556] The following examples and comparative examples are further described in detail to illustrate the features of the present application. The materials, amounts, proportions, processing contents, processing steps, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present application. Therefore, the scope of the present application should not be construed restrictively by the specific examples shown below.

[0557] Example 1

[0558] (Production of cellulose acylate film (substrate))

[0559] The following composition was put into a mixing tank and stirred, and further heated at 90°C for 10 minutes. Thereafter, the obtained composition was filtered using a filter paper having an average pore diameter of 34 μm and a sintered metal filter having an average pore diameter of 10 μm, thereby preparing a dope. The solid content concentration of the dope was 23.5 mass%, and the added amount of the plasticizer was 1.5 mass% with respect to the cellulose acylate. The solvent of the dope was dichloromethane / methanol / butanol = 81 / 18 / 1 (mass ratio).

[0560]

[0561] [Chemical Formula 5]

[0562]

[0563] [Chemical Formula 6]

[0564]

[0565] The dope produced in the above manner was cast using a roll film casting machine. The dope was cast from a die so as to be brought into contact with a metal support body cooled to 0°C, and the obtained web (film) was peeled. In addition, the roll was made of SUS.

[0566] After peeling the casted sheet (film) from the drum, the film was dried for 20 minutes at 30 to 40°C using a tenter device that grips both ends of the sheet with clips and transports it. Subsequently, the sheet was post-dried by area heating while being rolled. After knurling the obtained sheet, it was wound up.

[0567] The obtained cellulose acylate film had a film thickness of 40 μm, an in-plane retardation Re(550) of 1 nm at a wavelength of 550 nm, and a thickness direction retardation Rth(550) of 26 nm at a wavelength of 550 nm.

[0568] (Formation of optically anisotropic layer)

[0569] The cellulose acylate film produced in the above manner was subjected to rubbing treatment continuously. At this time, the length direction of the long sheet was parallel to the transport direction, and the angle formed by the length direction (transport direction) of the sheet and the rotation axis of the rubbing roll was set to 80°. The length direction (transport direction) of the sheet was set to 90°, and, as viewed from the sheet side, if the positive value is indicated in the clockwise direction from the sheet width direction as a reference (0°), the rotation axis of the rubbing roll was 10°. In other words, the position of the rotation axis of the rubbing roll was a position that was rotated counterclockwise by 80° from the length direction of the sheet as a reference.

[0570] A long cellulose acylate film subjected to the above rubbing treatment was used as a substrate, and an optically anisotropic layer-forming composition (1) containing a rod-like liquid crystalline compound having the following composition was applied using a die coater, thereby forming a composition layer (corresponding to Step 1A). In addition, the absolute value of the weighted average helical twisting power of the chiral agent in the composition layer in Step 1A was 0.0 μm -1 .

[0571] Next, the obtained composition layer was heated at 80°C for 60 seconds (corresponding to Step 2A). By this heating, the rod-like liquid crystalline compound of the composition layer was oriented in a prescribed direction.

[0572] Subsequently, under air containing oxygen (oxygen concentration: about 20 vol%), at 40°C, ultraviolet rays were irradiated to the composition layer using a 365 nm LED lamp (manufactured by Acroedge Co., Ltd.) for 5 seconds (irradiation amount: 13 mJ / cm 2 ) (corresponding to Step 3A).

[0573] Next, the obtained composition layer was heated at 80°C for 10 seconds (corresponding to Step 4A).

[0574] After that, nitrogen was blown to make the oxygen concentration 100 volume ppm, and ultraviolet rays were irradiated on the composition layer (irradiation amount: 500 mJ / cm 2 ) at 80°C using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) so as to form an optical anisotropic layer in which the alignment state of the liquid crystal compound was fixed (corresponding to Step 5A). The optical film (F-1) was produced in the above-described manner.

[0575] In addition, the molar absorption coefficient of the left-handed chiral agent (L1) in the composition (1) for forming an optical anisotropic layer at 365 nm was 40 L / (mol-cm), and the HTP with respect to this chiral agent did not change even if light of 365 nm was irradiated (13 mJ / cm 2 ) compared to before irradiation.

[0576] The molar absorption coefficient of the right-handed chiral agent (R1) at 365 nm was 38,450 L / (mol-cm), and the HTP with respect to this chiral agent decreased by 35 pm 2 if light of 365 nm was irradiated (13 mJ / cm -1 ).

[0577] The molar absorption coefficient of the photopolymerization initiator (Irgacure 819) at 365 nm was 860 L / (mol-cm).

[0578]

[0579]

[0580] Rod-shaped liquid crystal compound (A) (hereinafter, mixture of compounds) [Chemical Formula 7]

[0581]

[0582] Rod-shaped liquid crystal compound (B)

[0583] [Chemical Formula 8]

[0584]

[0585] Polymerizable compound (C)

[0586] [Chemical Formula 9]

[0587]

[0588] Left-handed chiral agent (L1)

[0589] [Chemical Formula 10]

[0590]

[0591] right-twisted chiral reagent (R1)

[0592] [Chem. 11]

[0593]

[0594] Polymer (A) (In the formula, the numerical values described in each repeating unit indicate the content of each repeating unit with respect to all repeating units (mass %).

[0595] [Chem. 12]

[0596]

[0597] Polymer (B) (In the formula, the numerical values described in each repeating unit indicate the content of each repeating unit with respect to all repeating units (mass %).

[0598] [Chem. 13]

[0599]

[0600] The optical film (F-1) produced in the above manner was cut in parallel with the rubbing direction, and the optically anisotropic layer was observed from the cross-sectional direction using a polarizing microscope. The thickness of the optically anisotropic layer was 2.7 μm, there was no uniform orientation of the twist angle in the region (2nd region) of the thickness (d2) 1.3 μm on the substrate side of the optically anisotropic layer, and the liquid crystal compound was twisted in the region (1st region) of the thickness (d1) 1.4 μm on the air side (the side opposite to the substrate) of the optically anisotropic layer.

[0601] In addition, the optical properties of the optical film (F-1) were calculated using Axoscan of Axometrics, Inc. and the analysis software (Multi-Layer Analysis) of Axometrics, Inc. The product of Δn2 and the thickness d2 (Δn2d2) in the 2nd region was 173 nm at a wavelength of 550 nm, the twist angle of the liquid crystal compound was 0°, and the angle of the orientation axis of the liquid crystal compound with respect to the length direction of the film was -10° on the side in contact with the substrate and -10° on the side in contact with the 1st region.

[0602] In addition, the optical properties of the optical film (F-1) were calculated using Axoscan of Axometrics, Inc. and the analysis software (Multi-Layer Analysis) of Axometrics, Inc. The product of Δn2 and the thickness d2 (Δn2d2) in the 2nd region was 173 nm at a wavelength of 550 nm, the twist angle of the liquid crystal compound was 0°, and the angle of the orientation axis of the liquid crystal compound with respect to the length direction of the film was -10° on the side in contact with the substrate and -10° on the side in contact with the 1st region.

[0603] In addition, the angle of the orientation axis of the liquid crystal compound contained in the optically anisotropic layer is set to 0° with respect to the length direction of the film, and the film is observed from the surface side of the optically anisotropic layer, and is expressed as negative when clockwise (right turn) and as positive when counterclockwise (left turn).

[0604] In addition, the angle of the orientation axis of the liquid crystal compound contained in the optically anisotropic layer is set to 0° with respect to the length direction of the film, and the film is observed from the surface side of the optically anisotropic layer, and is expressed as negative when clockwise (right turn) and as positive when counterclockwise (left turn).

[0605] (Production of polarizer)

[0606] A polyvinyl alcohol (PVA) film having a thickness of 80 μm was dyed by immersing in an iodine aqueous solution having an iodine concentration of 0.05 mass% for 60 seconds at 30°C. Subsequently, the obtained film was immersed in an aqueous boric acid solution having a boric acid concentration of 4 mass% for 60 seconds after being stretched in the longitudinal direction to 5 times the original length, and then dried at 50°C for 4 minutes, thereby obtaining a polarizer having a thickness of 20 μm.

[0607] (Production of polarizer protective film)

[0608] A commercially available cellulose acylate-based film, FUJITAC TG40UL (manufactured by Fujifilm Corporation), was immersed in an aqueous sodium hydroxide solution at 55°C at 1.5 mol / L, and then sufficiently washed with water. Subsequently, the obtained film was immersed in an aqueous dilute sulfuric acid solution at 35°C at 0.005 mol / L for 1 minute, and then sufficiently washed with water. Finally, the obtained film was sufficiently dried at 120°C, thereby producing a polarizer protective film subjected to a saponification treatment on the surface.

[0609] (Production of circularly polarizing plate)

[0610] The optical film (F-1) produced in the above manner was subjected to a saponification treatment in the same manner as in the production of the polarizer protective film, and the polarizer and the polarizer protective film were continuously attached to the substrate surface included in the optical film (F-1) using a polyvinyl alcohol-based adhesive, thereby producing a long strip-shaped circularly polarizing plate (P-1). That is, the circularly polarizing plate (P-1) has, in order, a polarizer protective film, a polarizer, a substrate, and an optically anisotropic layer.

[0611] In addition, the absorption axis of the polarizer coincides with the length direction of the circularly polarizing plate, the rotation angle of the in-plane slow axis of the second region with respect to the absorption axis of the polarizer is 10°, and the rotation angle of the in-plane slow axis of the surface on the side opposite to the second region side of the first region with respect to the absorption axis of the polarizer is 85°.

[0612] In addition, the angle of rotation of the above-mentioned in-plane slow axis is set to 0° with the length direction of the circularly polarizing plate as a reference, and the angle value is positive in the counterclockwise direction and negative in the clockwise direction, when the optically anisotropic layer is observed from the polarizer side.

[0613] Example 2

[0614] (alkali saponification treatment)

[0615] After passing the cellulose acylate film through a dielectric heating roller at a temperature of 60°C to raise the film surface temperature to 40°C, an alkali solution of the following composition was applied in an amount of 14 ml / m 2 to the film surface, and transported for 10 seconds under a steam-type far infrared heater manufactured by NORITAKE CO., LIMITED, which was heated to 110°C. Next, pure water was applied in an amount of 3 ml / m 2 using a bar coater in the same manner. After repeating water washing based on a spray coater and dehydration based on an air knife three times, drying was performed by transporting for 10 seconds to a drying area at 70°C, thereby producing a cellulose acylate film subjected to alkali saponification treatment.

[0616]

[0617]

[0618] (Formation of alignment film)

[0619] An alignment film coating solution of the following composition was continuously applied to the alkali saponification-treated surface of the cellulose acylate film using a wire bar #14. Drying was performed using a warm air at 60°C for 60 seconds, and further using a warm air at 100°C for 120 seconds.

[0620]

[0621] (Modified polyvinyl alcohol)

[0622] [Chemical Formula 14]

[0623]

[0624] (Formation of optically anisotropic layer)

[0625] Rubbing treatment was continuously performed on the alignment film produced in the above manner. At this time, the length direction of the long film was parallel to the transport direction, and the angle formed by the length direction (transport direction) of the film and the rotation axis of the rubbing roller was set to 45°. The length direction (transport direction) of the film was set to 90°, and, as viewed from the film side, if the positive value is indicated in the clockwise direction with the film width direction as the reference (0°), the rotation axis of the rubbing roller was 135°. In other words, the position of the rotation axis of the rubbing roller was a position rotated 45° counterclockwise from the reference of the length direction of the film.

[0626] A cellulose acylate film to which the above rubbing treatment was performed was used as a substrate, and an optical anisotropic layer-forming composition (2) containing a rod-like liquid crystal compound of the following composition was applied using a die coater, whereby a composition layer was formed (corresponding to Step 1C).

[0627] Next, the obtained composition layer was heated at 120°C for 80 seconds (corresponding to Step 2C). By this heating, the rod-like liquid crystal compound of the composition layer was aligned in a prescribed direction.

[0628] After that, under air containing oxygen (oxygen concentration: about 20 vol%), at 40°C, using a 365-nm LED lamp (manufactured by Acroedge Co., Ltd.), ultraviolet rays were irradiated onto the composition layer for 5 seconds (irradiation amount: 30 mJ / cm 2 ) (corresponding to Step 3C).

[0629] Next, the obtained composition layer was heated at 90°C for 10 seconds (corresponding to Step 4C).

[0630] After that, nitrogen gas was blown to make the oxygen concentration 100 vol ppm, and, at 55°C, using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.), ultraviolet rays were irradiated onto the composition layer (irradiation amount: 500 mJ / cm 2 ), whereby an optical anisotropic layer in which the alignment state of the liquid crystal compound was fixed was formed (corresponding to Step 5C). An optical film (F-2) was produced in the above manner.

[0631]

[0632] Rod-like liquid crystal compound (D)

[0633] [Chemical Formula 15]

[0634]

[0635] Rod-like liquid crystal compound (E)

[0636] [Chemical Formula 16]

[0637]

[0638] photosensitive compound (A)

[0639] [Chemical Formula 17]

[0640]

[0641] ionic compound (A)

[0642] [Chemical Formula 18]

[0643]

[0644] In addition, the photosensitive compound (A) in the composition (2) for forming an optically anisotropic layer generates a decomposed product (A) having a hydrophilic carboxyl group when irradiated with light of 365 nm at 30 mJ / cm 2 ).

[0645] decomposed product (A)

[0646] [Chemical Formula 19]

[0647]

[0648] The optically anisotropic layer was observed from the cross-sectional direction using a polarizing microscope after cutting the optical film (F-2) produced in the above-described manner in the rubbing direction. The thickness of the optically anisotropic layer was 4.3 μm, and the liquid crystal compound was uniformly oriented in a region (2nd region) of 3.0 μm in thickness on the substrate side of the optically anisotropic layer, and was vertically oriented in a region (1st region) of 1.3 μm in thickness on the air side (the side opposite to the substrate) of the optically anisotropic layer.

[0649] In addition, the optical properties of the optical film (F-2) were calculated using Axoscan of Axometrics, Inc. and analysis software (Multi-Layer Analysis) of Axometrics, Inc. The in-plane retardation (Δn2d2) at a wavelength of 550 nm in the 2nd region was 140 nm, and the angle of the in-plane slow axis with respect to the length direction of the film was -45°. Also, the in-plane retardation (Δn1d1) at a wavelength of 550 nm in the 1st region was 0 nm, and the thickness direction retardation at a wavelength of 550 nm in the 1st region was -60 nm.

[0650] In addition, the angle of the in-plane slow axis was set to 0° with the length direction of the film as a reference, and the substrate was observed from the surface side of the optically anisotropic layer, and was represented as negative when clockwise (right turn) and as positive when counterclockwise (left turn).

[0651] (Production of a circularly polarizing plate)

[0652] In the same manner as in Example 1, the optical film (F-2) produced in the above manner was subjected to saponification treatment, and the polarizer and the polarizer protective film were continuously attached to the substrate surface included in the optical film (F-2) using a polyvinyl alcohol-based adhesive, thereby producing a long strip-shaped circularly polarizing plate (P-2). That is, the circularly polarizing plate (P-2) had, in order, a polarizer protective film, a polarizer, a substrate, and an optically anisotropic layer.

[0653] In addition, the absorption axis of the polarizer coincided with the length direction of the circularly polarizing plate, and the rotation angle of the in-plane slow axis of the second region with respect to the absorption axis of the polarizer was 45°.

[0654] In addition, the rotation angle of the above in-plane slow axis was set to 0° with the length direction of the circularly polarizing plate as a reference, and the clockwise direction was expressed as a positive angle value and the counterclockwise direction was expressed as a negative angle value when the optically anisotropic layer was observed from the polarizer side.

[0655] <Example 3>

[0656] (Formation of optically anisotropic layer)

[0657] A rubbing treatment was continuously performed on the cellulose acylate film produced in Example 1. At this time, the length direction of the long strip-shaped film was parallel to the transport direction, and the angle formed by the length direction (transport direction) of the film and the rotation axis of the rubbing roll was 45°. In addition, the length direction (transport direction) of the film was set to 90°, and when the optically anisotropic layer was observed from the cellulose acylate film side, if a positive value was expressed in the counterclockwise direction with the width direction of the cellulose acylate film as a reference (0°), the rotation axis of the rubbing roll was 135°. In other words, the position of the rotation axis of the rubbing roll was a position rotated 45° in the clockwise direction with the length direction of the cellulose acylate film as a reference.

[0658] A composition layer (corresponding to Step 1D) was formed by coating, using a die coater, an optically anisotropic layer-forming composition (3) containing the following components, on the cellulose acylate film subjected to the above rubbing treatment, with the cellulose acylate film serving as a substrate.

[0659] Next, the obtained composition layer was heated at 80°C for 60 seconds (corresponding to Step 2D). By this heating, the rod-like liquid crystalline compound of the composition layer was oriented in a prescribed direction.

[0660] After that, under air containing oxygen (oxygen concentration: about 20% by volume), using a 365-nm LED lamp (manufactured by Acroedge Co., Ltd.), ultraviolet rays were irradiated onto the composition layer at 40°C for 5 seconds (irradiation amount: 50 mJ / cm 2 )(corresponding to Step 3D).

[0661] Next, the obtained composition layer was heated at 120°C for 10 seconds (corresponding to Step 4D). Further, the phase transition temperature of the rod-like liquid crystal compound in the composition (3) for optical anisotropy layer formation to the isotropic phase was 110°C.

[0662] After that, nitrogen gas was blown to make the oxygen concentration 100 volume ppm, and at 120°C, using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.), ultraviolet rays were irradiated on the composition layer (irradiation amount: 500 mJ / cm 2 ) to thereby form an optical anisotropy layer in which the orientation state of the liquid crystal compound was fixed (corresponding to Step 5D). The optical film (F-3) was produced in the above-described manner.

[0663] Further, the molar absorption coefficient of the photopolymerization initiator (Irgacure 907) at 365 nm was 140 L / (mol·cm).

[0664]

[0665]

[0666] The optical anisotropy layer of the optical film (F-3) produced in the above-described manner was cut in parallel with the rubbing direction, and the optical anisotropy layer was observed from the cross-sectional direction using a polarizing microscope. The thickness of the optical anisotropy layer was 2.7 μm, the liquid crystal compound was uniformly oriented in a region (2nd region) of 1.1 μm in thickness on the substrate side of the optical anisotropy layer, and the liquid crystal compound was in an isotropic state (isotropic phase) in a region (1st region) of 1.6 μm in thickness on the air side (the side opposite to the substrate) of the optical anisotropy layer.

[0667] Further, the optical properties of the optical film (F-3) were calculated using Axoscan of Axometrics Co. and analysis software (Multi-Layer Analysis) of Axometrics Co. The in-plane retardation (Δn2d2) at a wavelength of 550 nm of the 2nd region was 140 nm, and the in-plane slow axis was -45°. Furthermore, the in-plane retardation (Δn1d1) at a wavelength of 550 nm of the 1st region was 0 nm, and the retardation in the thickness direction was 0 nm.

[0668] Further, the angle of the in-plane slow axis was set to 0° based on the length direction of the film, the substrate was observed from the surface side of the optical anisotropy layer, and the clockwise (right turn) was indicated as negative, and the counterclockwise (left turn) was indicated as positive.

[0669] (Production of Circularly Polarizing Plate)

[0670] The optical film (F-3) produced in the above manner was subjected to saponification treatment in the same manner as in Example 1, and the polarizer and the polarizer protective film were continuously attached to the substrate surface included in the optical film (F-3) using a polyvinyl alcohol-based adhesive, thereby producing a long strip-shaped circularly polarizing plate (P-3). That is, the circularly polarizing plate (P-3) had the polarizer protective film, the polarizer, the substrate, and the optically anisotropic layer in this order.

[0671] In addition, the absorption axis of the polarizer coincided with the length direction of the circularly polarizing plate, and the rotation angle of the in-plane slow axis of the second region with respect to the absorption axis of the polarizer was 45°.

[0672] In addition, the rotation angle of the above in-plane slow axis was set to 0° with the length direction of the circularly polarizing plate as a reference when the optically anisotropic layer was observed from the polarizer side, and the clockwise direction was expressed with a positive angle value and the counterclockwise direction was expressed with a negative angle value.

[0673] <Example 4>

[0674] (Formation of optically anisotropic layer)

[0675] The cellulose acylate film produced in Example 1 was continuously subjected to rubbing treatment. At this time, the length direction of the long strip-shaped film was parallel to the transport direction, and the angle formed by the length direction (transport direction) of the film and the rotation axis of the rubbing roll was 90°.

[0676] A composition (4) for forming an optically anisotropic layer of a rod-like liquid crystal compound including the following composition was applied to the cellulose acylate film subjected to the above rubbing treatment as a substrate using a die coater, thereby forming a composition layer (corresponding to Step 1B). In addition, the absolute value of the weighted average helical twisting power of the chiral agent in the composition layer in Step 1B was 31 μm -1 .

[0677] Next, the obtained composition layer was heated at 100°C for 80 seconds (corresponding to Step 2B). The rod-like liquid crystal compound of the composition layer was oriented in a prescribed direction by this heating.

[0678] Subsequently, ultraviolet rays were irradiated to the composition layer using a 365 nm LED lamp (manufactured by Acroedge Co., Ltd.) under air containing oxygen (oxygen concentration: about 20 vol%) at 40°C for 10 seconds (irradiation amount: 100 mJ / cm 2 ) (corresponding to Step 3B).

[0679] Next, the obtained composition layer was heated at 90°C for 10 seconds (corresponding to Step 4B).

[0680] After that, nitrogen was blown to make the oxygen concentration 100 volume ppm, and ultraviolet rays were irradiated on the composition layer (irradiation amount: 500 mJ / cm2) at 55°C using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) so as to form an optical anisotropic layer in which the alignment state of the liquid crystal compound was fixed (corresponding to Step 5B). In this manner, the optical film (F-4) was produced. 2 ) composition layer, thereby forming an optical anisotropic layer in which the alignment state of the liquid crystal compound was fixed (corresponding to Step 5B). In this manner, the optical film (F-4) was produced.

[0681] In addition, the molar absorption coefficient of the sensitizer (KAYACURE DETX) at 365 nm was 4200 L / (mol-cm).

[0682]

[0683]

[0684] The optical anisotropic layer of the optical film (F-4) produced in the above manner was cut in parallel with the rubbing direction, and the optical anisotropic layer was observed from the cross-sectional direction using an SEM. The optical anisotropic layer had a thickness of 3.6 μm and had a region (2nd region) of the substrate side of the optical anisotropic layer having a thickness of 1.8 μm and a region (1st region) of the air side (the side opposite to the substrate) of the optical anisotropic layer having a thickness of 1.8 μm, and the 2nd region and the 1st region were cholesteric alignments having different helical pitches, respectively.

[0685] In addition, the spectral reflectance characteristics of the optical film (F-4) were calculated using an integrating sphere reflectometer. It was confirmed that the cholesteric liquid crystal film had a dual-band reflection band centered at 450 nm derived from the 2nd region and a reflection band centered at 650 nm derived from the 1st region.

[0686] <Comparative Example 1>

[0687] In the above-described Example 1, irradiation using a 365-nm LED lamp was performed under nitrogen blowing (oxygen concentration: 100 volume ppm) instead of performing irradiation based on a 365-nm LED lamp under air containing oxygen (oxygen concentration: about 20 volume %), and otherwise, the optical film (C-1) was produced in the same manner as the production method of the optical film (F-1) according to the same steps as Example 1. That is, Step 3A was not performed in Comparative Example 1.

[0688] In addition, as a result of observing the cross section of the optical anisotropic layer according to the same steps as the above-described Example 1, a uniform alignment was formed throughout the entire region in the thickness direction of the obtained optical anisotropic layer, and the desired effect of the present application was not obtained.

[0689] <Comparative Example 2>

[0690] In the foregoing Example 1, the optical film (C-2) was produced in the same manner as the production method of the optical film (F-1), except that, after the irradiation at 40°C using the LED lamp of 365 nm, the ultraviolet irradiation was performed at 40°C using the metal halide lamp without heating to 80°C. That is, in Comparative Example 2, the step 4A was not performed.

[0691] In addition, as a result of observing the cross section of the optically anisotropic layer in the same manner as in the foregoing Example 1, a uniform orientation was formed throughout the entire region in the thickness direction of the obtained optically anisotropic layer, and the desired effect of the present application was not obtained.

[0692] <Comparative Example 3>

[0693] In the foregoing Example 1, the irradiation conditions in the step 3A were changed to irradiation for 100 seconds using the LED lamp of 365 nm (irradiation amount: 13 mJ / cm 2 , and the optical film (C-3) was produced in the same manner as the production method of the optical film (F-1). That is, in Comparative Example 3, the irradiation amount was the same as in Example 1, but the irradiation time was extended.

[0694] In addition, as a result of observing the cross section of the optically anisotropic layer in the same manner as in the foregoing Example 1, a twisted orientation was formed throughout the entire region in the thickness direction of the obtained optically anisotropic layer, and the desired effect of the present application was not obtained.

[0695] The in-plane retardation Re(λ) at the wavelength λ of the produced optically anisotropic layer was measured using Axoscan manufactured by Axometrics Co. The results are shown in Table 1.

[0696] <Production of Organic EL Display Device and Evaluation of Display Performance>

[0697] <Installation on Display Device>

[0698] The GALAXY S4 manufactured by Samsung Electronics Co., Ltd. on which an organic EL panel was mounted was disassembled, and a circular polarizing plate was peeled off, and the circular polarizing plate (P-1) to (P-3) produced in the foregoing Examples was attached thereto in such a manner that the polarizer protective film was disposed on the outer side.

[0699] <Evaluation of Display Performance>

[0700] <Front Direction>

[0701] Black was displayed on the produced organic EL display device, and the display was observed from the front direction in bright light, and the coloring was evaluated based on the following criteria. The results are shown in Table 1.

[0702] 4: Coloration is completely invisible. (Allowed)

[0703] 3: Although coloration is slightly visible, it is slight. (Allowed)

[0704] 2: Coloration is visible, but the reflected light is small, and there is no problem in use. (Allowed)

[0705] 1: Coloration is visible, and the reflected light is also large, and cannot be allowed.

[0706] (Orientation direction)

[0707] Black was displayed on the produced organic EL display device, and the reflected light was observed from a polar angle of 45° under a fluorescent lamp, and the azimuthal dependence of the color tone change was evaluated with the following criteria. The results are shown in Table 1.

[0708] 4: Color difference is completely invisible. (Allowed)

[0709] 3: Although color difference is visible, it is very slight. (Allowed)

[0710] 2: Color difference is visible, but the reflected light is small, and there is no problem in use. (Allowed)

[0711] 1: Color difference is visible, and the reflected light is also large, and cannot be allowed.

[0712] In Table 1, "in-plane retardation" indicates the in-plane retardation at each wavelength of the optically anisotropic layer.

[0713] [Table 1]

[0714]

[0715] As shown in Table 1 above, it was confirmed that the phase difference of the optically anisotropic layer in each example showed inverse wavelength dispersion, and if the optically anisotropic layer was used for an organic EL display device, coloration and reflection were suppressed.

[0716] <Production of liquid crystal display device and evaluation of display performance>

[0717] (Production of circularly polarizing plate)

[0718] The optical film (F-1) produced in the above manner was subjected to saponification treatment, and the polarizer and the polarizer protective film were attached to the substrate surface included in the optical film (F-1) using a polyvinyl alcohol-based adhesive, thereby producing a circularly polarizing plate (P-4). At this time, the attachment was performed in such a manner that the angle formed by the absorption axis of the polarizer and the length direction of the optical film (F-1) became 90°. That is, the rotation angle of the in-plane slow axis of the second region with respect to the absorption axis of the polarizer was 100°, and the rotation angle of the in-plane slow axis of the surface on the side opposite to the second region side of the first region with respect to the absorption axis of the polarizer was 175°.

[0719] In addition, the rotation angle of the above in-plane slow axis was set to 0° with the absorption axis direction of the polarizer as a reference, and the clockwise direction was expressed by a positive angle value and the counterclockwise direction was expressed by a negative angle value when the optical anisotropic layer was observed from the polarizer side.

[0720] (Production of liquid crystal display device 1)

[0721] A VA-mode semi-transmissive liquid crystal display device 1 was produced in the following manner. The alignment film of the liquid crystal cell used polyimide, the cell gap of the transmissive portion was set to 4.0 μm, and the cell gap of the reflective portion was set to 2.0 μm. A nematic liquid crystal having a negative dielectric anisotropy was injected into the gap. The nematic liquid crystal was vertically aligned when no voltage was applied to the upper and lower substrates of the liquid crystal cell. Further, a protrusion was formed on the cell substrate to incline the nematic liquid crystal in two directions different by 180° in azimuth when a voltage was applied. The in-plane retardation of the transmissive portion was 280 nm and that of the reflective portion was 140 nm at a wavelength of 550 nm when a voltage was applied to the liquid crystal cell and white was displayed. The in-plane retardation of the transmissive portion was 0 nm and that of the reflective portion was 0 nm at a wavelength of 550 nm when no voltage was applied and black was displayed.

[0722] The circularly polarizing plate (P-1) and the circularly polarizing plate (P-4) produced in the above manner were attached to a liquid crystal cell composed of the upper and lower substrates and a liquid crystal layer interposed between the substrates, thereby producing a semi-transmissive liquid crystal display device 1. At this time, the circularly polarizing plate (P-1), the liquid crystal cell, the circularly polarizing plate (P-4), and a backlight were arranged in this order from the observer side. Further, they were arranged in such a manner that the circularly polarizing plate (P-1) became the polarizer and the optical film (F-1) in this order from the observer side and the circularly polarizing plate (P-4) became the optical film (F-1) and the polarizer in this order from the observer side, and the angle formed by the absorption axes of the respective polarizers included in the circularly polarizing plate (P-1) and the circularly polarizing plate (P-4) became 90°. Further, the rotation angle of the direction (in-plane slow axis) in which the major axis of the nematic liquid crystal interposed between the upper and lower substrates was projected onto the cell substrate when the nematic liquid crystal was inclined was 45°.

[0723] In addition, the angle of rotation of the above-mentioned projected direction (in-plane slow axis) was set to 0° with the absorption axis direction of the polarizer as a reference, and the clockwise direction was expressed as a positive angle value and the counterclockwise direction was expressed as a negative angle value, when the liquid crystal cell was observed from the side of the circular polarizer (P-1).

[0724] (Production of the circular polarizer)

[0725] An alignment film was formed on a cellulose acylate film in the same manner as the method described in Example 1 or Example 25 of Japanese Patent 6770649, and an optically anisotropic layer H composed of a discotic liquid crystal compound or an optically anisotropic layer Q composed of a rod-like liquid crystal compound was produced thereon. At this time, the thickness of the coating layer and the rubbing angle were adjusted to be the following retardation and slow axis angle. The in-plane retardation of the optically anisotropic layer H at a wavelength of 550 nm was 280 nm, and the in-plane retardation of the optically anisotropic layer Q at a wavelength of 550 nm was 120 nm.

[0726] Next, the circular polarizer (P-5) was produced by performing lamination in the order of the optically anisotropic layer Q, the optically anisotropic layer H, the aforementioned polarizer, and the aforementioned polarizer protective film using an adhesive. At this time, the cellulose acylate film and the alignment film were peeled off from the optically anisotropic layer H and the optically anisotropic layer Q, and were not included in the circular polarizer. Furthermore, the lamination was performed so that the angle of rotation of the in-plane slow axis of the optically anisotropic layer H with respect to the absorption axis of the polarizer was -75° and the angle of rotation of the in-plane slow axis of the optically anisotropic layer Q with respect to the absorption axis of the polarizer was -15°.

[0727] In addition, the angle of rotation of the above-mentioned in-plane slow axis was set to 0° with the absorption axis direction of the polarizer as a reference, and the clockwise direction was expressed as a positive angle value and the counterclockwise direction was expressed as a negative angle value, when the optically anisotropic layer was observed from the side of the polarizer.

[0728] (Production of the liquid crystal display device 2)

[0729] A semi-transmissive liquid crystal display device 2 of the ECB mode was produced in the following manner. The alignment film of the liquid crystal cell used polyimide, and the rubbing direction was parallel to the upper and lower directions. The cell gap of the transmissive portion was 4.0 μm, and the cell gap of the reflective portion was 2.0 μm, and a nematic liquid crystal having a positive dielectric anisotropy was injected into the space. The in-plane retardation at a wavelength of 550 nm when a voltage was applied to the liquid crystal cell was 280 nm in the transmissive portion when white was displayed and 140 nm in the reflective portion when white was displayed, 40 nm in the transmissive portion when black was displayed, and 20 nm in the reflective portion when black was displayed. Furthermore, when the nematic liquid crystal was inclined by being sandwiched by the upper and lower substrates by the application of a voltage, the direction in which the long axis of the nematic liquid crystal was projected onto the cell substrate (in-plane slow axis) coincided with the above-mentioned rubbing direction.

[0730] The circularly polarizing plate (P-1) and the circularly polarizing plate (P-5) produced above were attached to a liquid crystal cell composed of the upper and lower substrates and a liquid crystal layer interposed between the substrates, thereby producing a semi-transmissive liquid crystal display device 2. At this time, the circularly polarizing plate (P-5), the liquid crystal cell, the circularly polarizing plate (P-1), and a backlight were disposed in this order from the observer side. Further, they were disposed so that the circularly polarizing plate (P-5) becomes a polarizer, the optically anisotropic layer H, and the optically anisotropic layer Q in this order from the observer side and the circularly polarizing plate (P-1) becomes the optical film (F-1) and a polarizer in this order from the observer side. Further, they were disposed so that the angle formed by the absorption axes of the respective polarizers included in the circularly polarizing plate (P-5) and the circularly polarizing plate (P-1) becomes 90°, and the angle formed by the rubbing direction applied to the alignment film of the liquid crystal cell and the in-plane slow axis direction of the optically anisotropic layer Q included in the circularly polarizing plate (P-5) becomes 0°.

[0731] (Evaluation of display performance)

[0732] The transmission portion and the reflection portion of the VA-mode semi-transmissive liquid crystal display device 1 and the ECB-mode liquid crystal display device 2 produced above were adjusted in applied voltage, and the visibility of display of black and display of white was visually evaluated. It was confirmed that good white / black contrast was exhibited in either display device, and the optically anisotropic layer of the present embodiment can be preferably used for a liquid crystal display device.

[0733] <Example 5>

[0734] (Formation of optically anisotropic layer)

[0735] A rubbing treatment was continuously performed on the alignment film produced in Example 2. At this time, the length direction of the long strip-shaped film was parallel to the transport direction, and the angle formed by the length direction of the film (transport direction) and the rotation axis of the rubbing roller was set to 90°.

[0736] A cellulose acylate film with an alignment film subjected to the rubbing treatment described above was used as a substrate, and an optically anisotropic layer-forming composition (5) containing a rod-like liquid crystalline compound having the following composition was applied using a die coater, thereby forming a composition layer (corresponding to Step 1C).

[0737] Subsequently, the obtained composition layer was heated at 120°C for 80 seconds (corresponding to Step 2C). By this heating, the rod-like liquid crystalline compound of the composition layer was aligned in a prescribed direction.

[0738] After that, under air containing oxygen (oxygen concentration: about 20% by volume), using a 365-nm LED lamp (manufactured by Acroedge Co., Ltd.), ultraviolet rays were irradiated to the composition layer at 40°C for 5 seconds (irradiation amount: 30 mJ / cm2) (corresponding to Step 3C).2 )(corresponding to step 3C).

[0739] Next, the obtained composition layer was heated at 90°C for 10 seconds (corresponding to step 4C).

[0740] After that, nitrogen purge was performed to make the oxygen concentration 100 volume ppm, and at 55°C, using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.), ultraviolet rays were irradiated (irradiation amount: 500 mJ / cm2) on the composition layer, thereby forming an optical anisotropic layer in which the alignment state of the liquid crystal compound was fixed (corresponding to step 5C). In the above-described manner, the optical film (F-5) was produced. 2 ) composition layer, thereby forming an optical anisotropic layer in which the alignment state of the liquid crystal compound was fixed (corresponding to step 5C). In the above-described manner, the optical film (F-5) was produced.

[0741]

[0742]

[0743] Rod-like liquid crystal compound (F) [Chemical Formula 20]

[0744]

[0745] Rod-like liquid crystal compound (G) [Chemical Formula 21]

[0746]

[0747] Rod-like liquid crystal compound (H) [Chemical Formula 22]

[0748]

[0749] Rod-like liquid crystal compound (I) [Chemical Formula 23]

[0750]

[0751] The optical film (F-5) produced in the above-described manner was cut in parallel with the rubbing direction, and the optical anisotropic layer was observed from the cross-sectional direction using a polarizing microscope. The thickness of the optical anisotropic layer was 4.3 μm, and in a region (2nd region) of 2.4 μm in thickness on the substrate side of the optical anisotropic layer, the liquid crystal compound was uniformly aligned, and in a region (1st region) of 1.9 μm in thickness on the air side (the side opposite to the substrate) of the optical anisotropic layer, the liquid crystal compound was perpendicularly aligned.

[0752] In addition, the optical properties of the optical film (F-5) were calculated using Axoscan by Axometrics and analysis software (Multi-Layer Analysis) by Axometrics. The in-plane retardation of the second region (Δn2d2) at a wavelength of 550 nm was 130 nm, and the angle of the in-plane slow axis with respect to the longitudinal direction of the film was 0°. Also, the in-plane retardation of the first region (Δn1d1) at a wavelength of 550 nm was 0 nm, and the thickness direction retardation of the first region at a wavelength of 550 nm was -100 nm.

[0753] In addition, the angle of the in-plane slow axis was set to 0° with respect to the longitudinal direction of the film.

[0754] (Production of optical compensation sheet for liquid crystal display device)

[0755] The optical film (F-5) produced in the above manner was subjected to saponification treatment, and the polarizer and the polarizer protective film were continuously attached to the optical anisotropic layer surface included in the optical film (F-5) using a polyvinyl alcohol-based adhesive, thereby producing a long polarizing plate (P-6). That is, the polarizing plate (P-6) had a polarizer protective film, a polarizer, an optical anisotropic layer, and a substrate in this order.

[0756] In addition, the absorption axis of the polarizer coincided with the longitudinal direction of the polarizing plate, and the rotation angle of the in-plane slow axis of the second region with respect to the absorption axis of the polarizer was 0°.

[0757] In addition, the rotation angle of the in-plane slow axis was set to 0° with respect to the longitudinal direction of the polarizing plate when the optical anisotropic layer was observed from the polarizer side.

[0758] (Production of liquid crystal display device 3)

[0759] The polarizing plate on the front side was peeled off from a commercially available liquid crystal display device (iPad (registered trademark), manufactured by Apple Inc.) (a liquid crystal display device including a liquid crystal cell in FFS mode), and the above-produced polarizing plate (P-6) was attached in such a manner that the optical film side was disposed on the liquid crystal cell side and the absorption axis of the polarizer was orthogonal to the absorption axis of the polarizer in the polarizing plate on the backlight side using a 20-μm acrylic adhesive, thereby producing a liquid crystal display device 3.

[0760] (Evaluation of display performance)

[0761] Regarding the above-produced liquid crystal display device 3, the applied voltage was adjusted, and the visibility of the inclination direction of the display black and the display white was visually evaluated. It was confirmed that the liquid crystal display device 3 displayed a good white / black contrast, and the optical anisotropic layer of the present embodiment could be preferably used for an optical compensation sheet for a liquid crystal display device.

[0762] Symbol explanation

[0763] 10 - substrate, 12, 120, 220, 320, 420 - composition layer, 12A, 120A, 220A, 320A, 420A - lower side region, 12B, 120B, 220B, 320B, 420B - upper side region, 20 - optically anisotropic layer, 22 - other optically anisotropic layer, 24 - laminate, 26 - polarizer, 28 - optically anisotropic layer with polarizer.

Claims

1. A method for producing an optically anisotropic layer, comprising: Process 1 in which a composition layer is formed, the composition layer containing a chiral agent, the chiral agent containing a photosensitive chiral agent whose helical twisting power changes by light irradiation, and the composition layer containing a liquid crystal compound having a polymerizable group; Process 2 in which a heating treatment is performed on the composition layer to orient the liquid crystal compound in the composition layer; Process 3, which is performed after the process 2, is irradiation of the composition layer with 300 mJ / cm 2 The following light irradiation is performed for 50 seconds or less; Process 4, which is performed after the Process 3, in which a heating treatment is performed on the composition layer at a higher temperature than at the time of the light irradiation; and Process 5, which is performed after the Process 4, in which a curing treatment is performed on the composition layer to form an optically anisotropic layer having a plurality of regions in which the orientation state of the liquid crystal compound differs in the thickness direction.

2. The method for producing an optically anisotropic layer according to claim 1, wherein the composition layer contains a photosensitive material selected from the group consisting of a photopolymerization initiator and a photosensitizer, the molar absorption coefficient of the photosensitive material at the wavelength of the light irradiation in the Process 3 is 5000 L / (mol·cm) or less.

3. The method for producing an optically anisotropic layer according to claim 1, wherein the total content of the chiral agent is 5.0 mass% or less with respect to the total mass of the liquid crystal compound.

4. The method for producing an optically anisotropic layer according to claim 1, wherein the total content of the chiral agent exceeds 5.0 mass% with respect to the total mass of the liquid crystal compound.

5. A method for producing an optically anisotropic layer, comprising: Process 1 in which a composition layer is formed, the composition layer containing a photosensitive compound whose polarity changes by light irradiation, and the composition layer containing a liquid crystal compound having a polymerizable group; Process 2 in which a heating treatment is performed on the composition layer to orient the liquid crystal compound in the composition layer; Process 3, which is performed after the process 2, is irradiation of the composition layer with 300 mJ / cm 2 The following light irradiation is performed for 50 seconds or less; Process 4, which is performed after the Process 3, in which a heating treatment is performed on the composition layer at a higher temperature than at the time of the light irradiation; and Process 5, which is performed after the Process 4, in which a curing treatment is performed on the composition layer to form an optically anisotropic layer having a plurality of regions in which the orientation state of the liquid crystal compound differs in the thickness direction.

6. The method for producing an optically anisotropic layer according to claim 5, wherein the photosensitive compound is a photosensitive compound that is hydrophilized by light irradiation.

7. The method for producing an optically anisotropic layer according to claim 1, 2, or 5, wherein the temperature of the heating treatment in the Process 4 is a temperature that is the temperature at which the liquid crystal compound becomes an isotropic phase or more.

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