Optically anisotropic layer

Abstract

The present application provides an optically anisotropic layer having a plurality of regions with different alignment states of liquid crystal compounds in the thickness direction, and being less likely to generate peeling within the layer. The optically anisotropic layer of the present application is an optically anisotropic layer formed using a liquid crystal compound, the optically anisotropic layer containing a leveling agent, and in a distribution of secondary ion intensity originating from the leveling agent in the depth direction of the optically anisotropic layer obtained by irradiating an ion beam from one surface of the optically anisotropic layer toward the other surface while analyzing the components in the depth direction of the optically anisotropic layer by time-of-flight secondary ion mass spectrometry, a prescribed requirement is satisfied.

Description

Technical Field

[0001] This invention relates to an optical anisotropic layer. Background Technology

[0002] Phase retardation layers (optical anisotropic layers) with refractive index anisotropy are suitable for various applications such as anti-reflective films for display devices and optical compensation films for liquid crystal display devices.

[0003] As described in Patent Document 1, a stacked optical anisotropic layer consisting of multiple layers is disclosed as an optical anisotropic layer formed using liquid crystal compounds.

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-036657 Summary of the Invention

[0007] The technical problem to be solved by the invention

[0008] Conventionally, in manufacturing a stacked optical anisotropic layer as described in Patent Document 1, the stacked optical anisotropic layer is formed by coating each layer. Therefore, by changing the conditions for forming each layer, the orientation state of the liquid crystal compound in the thickness direction of the optical anisotropic layer can be altered.

[0009] In addition, compositions used to form optical anisotropic layers often contain leveling agents.

[0010] On the other hand, the inventors have discovered that in conventional optical anisotropic layers formed by coating multiple compositions, peeling is prone to occur within the optical anisotropic layer, requiring improvement. For example, it has been found that if a cross-cutting test is performed on a conventional optical anisotropic layer fixed to a substrate, peeling is prone to occur within the optical anisotropic layer.

[0011] In view of the above, the objective of the present invention is to provide an optically anisotropic layer having multiple regions in the thickness direction with different orientation states of liquid crystal compounds, and which is not easily delaminated within the layer.

[0012] means for solving technical problems

[0013] Based on in-depth research into the problems of the prior art, the inventors discovered that the above-mentioned issues can be solved through the following structure.

[0014] (1) An optically anisotropic layer formed using a liquid crystal compound, wherein,

[0015] The optical anisotropic layer contains a leveling agent.

[0016] While irradiating an ion beam from one surface of an optically anisotropic layer to another, time-of-flight secondary ion mass spectrometry was used to analyze the depth-direction composition of the optically anisotropic layer to obtain the depth-direction distribution of secondary ion intensities originating from the leveling agent. Among the secondary ion intensities originating from the leveling agent on one surface and the other surface of the optically anisotropic layer, the secondary ion intensity with the larger leveling agent intensity was designated as the first intensity, and the secondary ion intensity that would be 1 / 1000 of the first intensity was designated as the second intensity. Furthermore, when the depth position representing the second intensity closest to one surface in the distribution was designated as the first position, and the depth position representing the second intensity closest to the other surface in the distribution was designated as the second position, no secondary ion intensity originating from the leveling agent greater than 1 / 500 of the first intensity was observed at any depth in the region between the first and second positions.

[0017] The optical anisotropic layer satisfies any one of the following requirements 1 to 3.

[0018] Requirement 1: The optical anisotropic layer is an optical anisotropic layer formed by fixing a cholesterol-type liquid crystal phase, and has multiple regions with different helical pitches of the cholesterol-type liquid crystal phase along the thickness direction.

[0019] Requirement 2: The optical anisotropic layer is an optical anisotropic layer formed by fixing the orientation state of the liquid crystal compound, and has multiple regions along the thickness direction in which the orientation direction of the liquid crystal compound has different tilt angles relative to the surface of the optical anisotropic layer.

[0020] Requirement 3: The optical anisotropic layer has a region along the thickness direction that fixes the orientation state of the liquid crystal compound and a region that fixes the state of the liquid crystal compound displaying an isotropic phase.

[0021] (2) The optical anisotropic layer according to (1) satisfies requirement 1.

[0022] (3) The optical anisotropic layer according to (2), wherein the optical anisotropic layer has two regions with different helical pitches of the cholesterol-type liquid crystal phase.

[0023] (4) The optical anisotropic layer according to (1) satisfies requirement 2.

[0024] (5) The optical anisotropic layer according to (4), wherein the optical anisotropic layer has a region for fixing the orientation state of the parallel-oriented liquid crystal compound and a region for fixing the orientation state of the vertically oriented liquid crystal compound.

[0025] (6) The optical anisotropic layer according to (1) satisfies requirement 3.

[0026] (7) The optical anisotropic layer according to (6), wherein the optical anisotropic layer has a region for fixing the orientation state of the parallel-oriented liquid crystal compound and a region for fixing the state of the liquid crystal compound displaying an isotropic phase.

[0027] Invention Effects

[0028] According to the present invention, an optical anisotropic layer can be provided, which has multiple regions with different orientation states of liquid crystal compounds in the thickness direction, and is not prone to peeling within the layer. Attached Figure Description

[0029] Figure 1 This is a schematic diagram illustrating the distribution of secondary ion intensity originating from leveling agents in the depth direction, detected by analyzing the composition of optical anisotropic layers using time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0030] Figure 2 It means Figure 1 A schematic diagram of an example of an optical anisotropic layer.

[0031] Figure 3 This is a cross-sectional view showing one embodiment of an optical anisotropy layer that satisfies requirement 1.

[0032] Figure 4 This is a cross-sectional view of a composition layer as an example of step 3A of a method for manufacturing an optical anisotropic layer that satisfies requirement 1.

[0033] Figure 5 This is a cross-sectional view of a composition layer as an example of step 4A of a method for manufacturing an optical anisotropic layer that satisfies requirement 1.

[0034] Figure 6 It plots the helical torsional force (HTP) (μm) of chiral reagent A. -1 ) and light irradiance (mJ / cm 2 A diagram illustrating the relationship between ).

[0035] Figure 7 This is a cross-sectional view showing one embodiment of an optical anisotropy layer that satisfies requirement 2.

[0036] Figure 8 This is a cross-sectional view of a composition layer as an example of step 3B in a method for manufacturing an optical anisotropic layer that satisfies requirement 2.

[0037] Figure 9This is a cross-sectional view of a composition layer as an example of step 4B in a method for manufacturing an optical anisotropy layer that satisfies requirement 2.

[0038] Figure 10 This is a cross-sectional view showing one embodiment of an optical anisotropy layer that satisfies requirement 3.

[0039] Figure 11 This is a cross-sectional view of a composition layer as an example of step 3C in a method for manufacturing an optical anisotropy layer that satisfies requirement 3.

[0040] Figure 12 This is a cross-sectional view of a composition layer as an example of step 4C in a method for manufacturing an optical anisotropy layer that satisfies requirement 3.

[0041] Figure 13 This is a cross-sectional view showing one embodiment of the laminate of the present invention.

[0042] Figure 14 This is a cross-sectional view showing one embodiment of the optical anisotropy layer with a polarizer according to the present invention. Detailed Implementation

[0043] The present invention will now be described in detail. Furthermore, in this specification, the numerical range indicated by "~" represents the range encompassed by the values ​​described before and after "~" as a lower and upper limit. First, the terminology used in this specification will be explained.

[0044] Unless otherwise specified, the slow axis is defined at 550 nm.

[0045] In this invention, Re(λ) and Rth(λ) represent the in-plane delay and the thickness direction delay at wavelength λ, respectively. Unless otherwise specified, wavelength λ is set to 550 nm.

[0046] In this invention, Re(λ) and Rth(λ) are values ​​obtained by measurement at wavelength λ using an AxoScan (manufactured by Axometrics). They are calculated by inputting the average refractive index ((nx+ny+nz) / 3) and film thickness (d(μm)) into the AxoScan.

[0047] Slow axis direction (°)

[0048] Re(λ)=R0(λ)

[0049] Rth(λ)=((nx+ny) / 2-nz)×d.

[0050] Additionally, R0(λ) is shown as a value calculated using AxoScan, but it represents Re(λ).

[0051] In this specification, the refractive indices nx, ny, and nz are measured using an Abbe refractometer (NAR-4T, manufactured by ATAGO CO.,LTD.) and a sodium lamp (λ = 589 nm) as the light source. Furthermore, when measuring wavelength dependence, measurements can be performed using a multi-wavelength Abbe refractometer DR-M2 (manufactured by ATAGO CO.,LTD.) combined with an interference filter.

[0052] Furthermore, values ​​from the Polymer Handbook (JOHN WILEY & SONS, INC) and various optical film catalogs can be used. The average refractive index values ​​for major optical films are exemplified below: cellulose acylates (1.48), cyclic olefin polymers (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).

[0053] In this specification, "light" refers to activating light or radiation, such as the bright-line spectrum of a mercury lamp, far-ultraviolet light represented by an excimer laser, extreme ultraviolet (EUV) light, X-rays, ultraviolet light, and electron beams (EB). Among these, ultraviolet light is preferred.

[0054] In this specification, "visible light" refers to light in the range of 380–780 nm. Furthermore, unless otherwise specified, the measurement wavelength is 550 nm.

[0055] As a characteristic feature of the optical anisotropic layer of the present invention, the leveling agent is distributed at a predetermined position in the thickness direction of the optical anisotropic layer.

[0056] Based on their research into the prior art, the inventors discovered the following: In the prior art, the composition used to form the optical anisotropic layer contains a leveling agent. When this composition is applied two or more times to form an optical anisotropic layer with regions having different orientation states of multiple liquid crystal compounds in the thickness direction, regions where the leveling agent is unevenly distributed exist within the optical anisotropic layer. Furthermore, it was found that peeling easily occurs in these unevenly distributed regions.

[0057] In contrast, it has been found that the present invention can solve the above-mentioned problems by controlling the distribution of leveling agent inside the optical anisotropic layer.

[0058] The optical anisotropic layer of the present invention will now be described in detail.

[0059] The optical anisotropy layer of the present invention is a layer formed using a liquid crystal compound.

[0060] More specifically, the optical anisotropic layer of the present invention is an optical anisotropic layer that satisfies requirements 1 to 3 described later, the details of which will be described in detail later.

[0061] Furthermore, as described later, the optical anisotropy layer of the present invention may include regions in which optical anisotropy is not displayed in the thickness direction.

[0062] The optical anisotropic layer of the present invention contains a leveling agent.

[0063] There are no particular limitations on the leveling agent, but from the viewpoint of easily forming the distribution of the leveling agent described later, fluorinated leveling agents or silicone leveling agents are preferred, and fluorinated leveling agents are more preferred.

[0064] Fluorinated leveling agents are leveling agents containing fluorine atoms, preferably containing fluorinated aliphatic groups.

[0065] Fluorine leveling agents preferably have repeating units represented by formula (1).

[0066] [Chemical Formula 1]

[0067]

[0068] In equation (1), R 1 It represents a hydrogen atom, a halogen atom, or a methyl group.

[0069] L 1 This indicates a single bond or a divalent linking group. There are no particular limitations on the divalent linking group; examples include divalent hydrocarbon groups (e.g., divalent aliphatic hydrocarbon groups such as alkylene groups with 1-10 carbon atoms, alkenyl groups with 1-10 carbon atoms, and alkyne groups with 1-10 carbon atoms, as well as divalent aromatic hydrocarbon groups such as arylene groups), divalent heterocyclic groups, -O-, -S-, -NH-, -CO-, or groups formed by combining these (e.g., -CO-O-, -O-divalent hydrocarbon group, -(O-divalent hydrocarbon group)). m -O- (m represents an integer greater than 1) and -O-CO-2 valence hydrocarbon groups, etc.

[0070] n represents an integer from 1 to 18, preferably an integer from 4 to 12, and more preferably an integer from 6 to 8.

[0071] X is a hydrogen atom or a fluorine atom.

[0072] From the viewpoint that it is easier to form the distribution of the leveling agent described later, the repeating unit represented by formula (1) is preferably the repeating unit represented by formula (2).

[0073] [Chemical Formula 2]

[0074]

[0075] In equation (2), R 1 The definitions of , n and X are the same as the definitions of each group in the above formula (1).

[0076] Y represents an oxygen atom, a sulfur atom, or -N(R) 2 )-. R 2 It represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms that may have substituents.

[0077] m represents an integer from 1 to 6, preferably an integer from 1 to 3.

[0078] Fluorinated leveling agents may have only one repeating unit represented by formula (1), or they may have two or more repeating units.

[0079] The content of the repeating unit represented by formula (1) in the fluorinated leveling agent is not particularly limited. From the viewpoint of easily forming the distribution of the leveling agent described later, the content of all repeating units in the fluorinated leveling agent is preferably 20 to 100% by mass, more preferably 30 to 95% by mass.

[0080] When the fluorinated leveling agent has two or more repeating units represented by formula (1), the total content is preferably within the above range.

[0081] Fluorinated leveling agents may have repeating units other than those represented by formula (1).

[0082] Other repeating units may include repeating units containing hydrophilic groups (e.g., poly(oxyalkylene) groups, hydroxyl groups, etc.).

[0083] Fluorinated leveling agents can have repeating units as represented by formula (3).

[0084] [Chemical Formula 3]

[0085]

[0086] R 3 It represents a hydrogen atom, a halogen atom, or a methyl group.

[0087] L 2 This indicates a single bond or a divalent linker. The definition of a divalent linker is as described above.

[0088] L 3 This indicates an alkylene group. The preferred number of carbon atoms in an alkylene group is 2 to 3.

[0089] p represents an integer from 4 to 20, preferably an integer from 5 to 15.

[0090] R 4This represents a hydrogen atom or a substituent. Examples of substituents include alkyl, alkoxy, halogen, aryl, cyano, hydroxyl, amino, or combinations thereof (e.g., -alkylene-OH, etc.).

[0091] Fluorine leveling agents may have only one repeating unit represented by formula (3), or they may have two or more repeating units.

[0092] The content of the repeating unit represented by formula (3) in the fluorinated leveling agent is not particularly limited. From the viewpoint of easily forming the distribution of the leveling agent described later, the content of all repeating units in the fluorinated leveling agent is preferably 2 to 70% by mass, more preferably 5 to 60% by mass.

[0093] When the fluorinated leveling agent has two or more repeating units represented by formula (3), its total content is preferably within the above range.

[0094] There is no particular limitation on the weight-average molecular weight of fluorinated leveling agents, but from the viewpoint of easily forming the distribution of leveling agents described later, it is preferably 3,000 to 30,000, and more preferably 5,000 to 25,000.

[0095] As a silicone-based leveling agent, a leveling agent containing multiple dialkylsiloxy units as repeating units is preferred.

[0096] There is no particular limitation on the content of leveling agent in the optical anisotropic layer, but from the viewpoint that an optical anisotropic layer that is less prone to peeling can be obtained (hereinafter also referred to as "the viewpoint of superior effect of the present invention"), the content is preferably 0.010 to 5.000% by mass relative to the total mass of the optical anisotropic layer, more preferably 0.020 to 2.000% by mass.

[0097] The optical anisotropic layer may contain materials other than those mentioned above.

[0098] Other materials that may be included in the compositions used to form the optical anisotropic layers described later are given below. Details will be provided later.

[0099] While irradiating an ion beam from one surface of the optical anisotropic layer to another surface, the composition in the depth direction of the optical anisotropic layer is analyzed using time-of-flight secondary ion mass spectrometry to obtain the distribution of secondary ion intensity originating from the leveling agent in the depth direction. Among the secondary ion intensity originating from the leveling agent on one surface of the optical anisotropic layer and the secondary ion intensity originating from the leveling agent on the other surface of the optical anisotropic layer, the secondary ion intensity originating from the leveling agent with the larger intensity is designated as the first intensity, and the secondary ion intensity that becomes 1 / 1000 of the first intensity is designated as the second intensity. Furthermore, when the depth position representing the second intensity on the side closest to the first surface in the distribution is designated as the first position, and the depth position representing the second intensity on the side closest to the other surface in the distribution is designated as the second position, no secondary ion intensity originating from the leveling agent greater than 1 / 500 of the first intensity is observed at any depth in the region between the first and second positions.

[0100] The above-mentioned requirements will now be described in detail using the accompanying drawings. Furthermore, in the drawings shown below, the invention is illustrated in a form different from the actual data, such as using a scale, for ease of understanding.

[0101] exist Figure 1 The diagram illustrates an example of obtaining a compositional distribution in each layer by analyzing the depth direction using TOF-SIMS while sputtering ions from one surface of the optical anisotropic layer towards another. Furthermore, in this specification, the depth direction refers to the direction from one surface of the optical anisotropic layer towards another.

[0102] exist Figure 1 In the depth distribution recorded in the document, the horizontal axis ( Figure 1 In the middle, the axis extending left and right along the plane of the paper represents the depth with reference to one surface of the optical anisotropic layer, and the vertical axis ( Figure 1 In the figure, the axis extending vertically along the paper surface represents the secondary ionic strength derived from the leveling agent.

[0103] In addition, regarding the TOF-SIMS method, specifically, it is described in "Secondary Ion Mass Spectrometry" edited by The Japan Society of Vacuum and Surface Science, MARUZEN GROUP (published in 1999).

[0104] Figure 1 The distribution in corresponds to one side from Figure 2The results are obtained by sputtering ions from one surface 12A (the surface of the optical anisotropic layer 12 opposite to the substrate 10) of the optical anisotropic layer 12 disposed on the substrate 10 toward the other surface 12B (the surface of the optical anisotropic layer 12 on the substrate 10 side) and analyzing the composition in the depth direction of each layer using TOF-SIMS.

[0105] in addition, Figure 2 The optical anisotropic layer 12 shown corresponds to an example of a method in which an optical anisotropic layer forming composition containing specified components (liquid crystal compound and leveling agent) is coated onto a substrate 10.

[0106] Figure 1 The position with the horizontal axis at 0 corresponds to surface 12A of the optical anisotropic layer 12, and the position with the horizontal axis at E corresponds to surface 12B of the optical anisotropic layer 12. That is, the horizontal axis from 0 to E corresponds to one surface to another of the optical anisotropic layer 12.

[0107] In addition, while irradiating the ion beam, the composition of the optical anisotropic layer in the depth direction is analyzed using TOF-SIMS. After performing composition analysis in the surface depth region of 1 to 2 nm, a series of operations are repeated to further mine in the depth direction from 1 nm to several hundred nm and perform composition analysis in the next surface depth region of 1 to 2 nm.

[0108] exist Figure 1 The distribution along the depth direction shows the results of the secondary ionic strength originating from the leveling agent.

[0109] Furthermore, in this specification, the "secondary ion strength originating from the leveling agent" obtained by analyzing the distribution in the depth direction of the optical anisotropic layer using TOF-SIMS analysis of the composition in the depth direction refers to the strength of fragment ions originating from the leveling agent.

[0110] like Figure 1 As shown, if an ion beam is irradiated from one surface of the optical anisotropic layer towards another while the composition of the optical anisotropic layer in the depth direction is analyzed using the TOF-SIMS method, the intensity of secondary ions originating from the leveling agent is initially observed to be high. However, as the ion beam is further irradiated towards the depth direction, its intensity gradually decreases. Furthermore, when irradiating towards the other surface, the intensity of secondary ions originating from the leveling agent remains low, and its intensity begins to increase as it approaches the other surface.

[0111] Leveling agents tend to be unevenly distributed on the air interface side and the substrate interface side (especially the air interface side). Therefore, as mentioned above, the secondary ionic strength derived from the leveling agent tends to be high near one surface and near the other.

[0112] Next, baselines are plotted in the distribution obtained in the manner described above to determine the benchmark for secondary ion intensity. Specifically, as follows: Figure 1 As shown, draw the baseline BL represented by the thick dashed line and set this position as the point where the secondary ion strength is 0.

[0113] Furthermore, as a method for drawing the baseline, firstly, when a reference position SP1 is set at a depth equivalent to 1 / 10 of the total thickness of the optical anisotropic layer from one surface to the other, and a reference position SP2 is set at a depth equivalent to 9 / 10 of the total thickness of the optical anisotropic layer, the average value of the secondary ion intensity originating from the leveling agent located between reference positions SP1 and SP2 is calculated, and the baseline is drawn using this average value. That is, the average value of the secondary ion intensity originating from the leveling agent in the region between reference positions SP1 and SP2 is calculated, a straight line representing this average value is drawn along the horizontal axis, and this straight line is set as the baseline.

[0114] Next, in the distribution obtained in the above manner, the secondary ion intensity originating from the leveling agent on one surface of the optical anisotropic layer and the secondary ion intensity originating from the leveling agent on the other surface of the optical anisotropic layer are assigned the higher intensity as the first intensity. Figure 1 In the middle, the secondary ionic strength originating from the leveling agent on one surface corresponding to the surface of the optical anisotropic layer on the side opposite to the substrate ( Figure 1 The secondary ion intensity of the leveling agent at a depth position of 0 in the middle is greater than the secondary ion intensity of the leveling agent on the other surface corresponding to the substrate side surface of the optical anisotropy layer. Figure 1 The secondary ion intensity of the leveling agent at the depth position E is used to define the first intensity S1 on the surface corresponding to the surface of the optical anisotropic layer on the side opposite to the substrate.

[0115] In addition, such as Figure 1 As shown, the first intensity S1 refers to the intensity based on the baseline BL. That is, the first intensity S1 is calculated as the secondary ion intensity at position 0 of the baseline BL.

[0116] Next, the secondary ion strength, which will be 1 / 1000 of the first strength S1, will be set as the second strength S2.

[0117] The secondary ion intensity derived from the leveling agent on one surface of the aforementioned optical anisotropic layer is taken as the maximum value of the secondary ion intensity derived from the leveling agent in a region of 10 nm along the depth direction from one surface.

[0118] Furthermore, the secondary ion intensity derived from the leveling agent on the other surface of the aforementioned optical anisotropy layer is taken as the maximum value of the secondary ion intensity derived from the leveling agent in the region between the other surface and one surface side within 10 nm.

[0119] Next, in Figure 1 In the distribution shown, the depth position representing the second intensity S2 closest to the substrate side is set as the first position P1, and the depth position representing the second intensity S2 closest to the other substrate side is set as the second position P2.

[0120] Next, the secondary ion intensity originating from the leveling agent was observed at a depth within the region between the first position P1 and the second position P2. In the optical anisotropy layer of the present invention, no secondary ion intensity originating from the leveling agent greater than 1 / 500 of the first intensity S1 was observed at any depth within the region between the first position P1 and the second position P2. More specifically, in Figure 1 The intensity shown is 1 / 500 of the first intensity S1 as the third intensity S3, and it is observed that the secondary ion intensity originating from the leveling agent at any depth position in the region between the first position P1 and the second position P2 is not greater than the third intensity S3.

[0121] By satisfying the requirements described above, the delamination of the interior of the optical anisotropic layer is suppressed.

[0122] Furthermore, if the secondary ion strength originating from the leveling agent is above the third strength S3 at any depth position in the region between the first position P1 and the second position P2, peeling is likely to occur near the depth position above the third strength S3, and the effect of the present invention cannot be obtained.

[0123] Regarding the distribution state of the leveling agent as described above, it can be achieved, for example, through the steps of the manufacturing method for an optically anisotropic layer that satisfies any one of requirements 1 to 3 described later. In the manufacturing method described later, the optically anisotropic layer can be achieved by coating the composition once, and the optically anisotropic layer has multiple regions with different orientation states of liquid crystal compounds in the thickness direction. Therefore, in the composition layer formed by coating the composition in this step, the leveling agent is easily unevenly distributed on the air interface side or the substrate side on which the composition is coated. As a result, the above-mentioned distribution state of the leveling agent can be achieved in the optically anisotropic layer, and multiple regions with different orientation states of liquid crystal compounds can be formed in the thickness direction.

[0124] The optical anisotropic layer of the present invention satisfies any one of the following requirements 1 to 3.

[0125] Requirement 1: The optical anisotropic layer is an optical anisotropic layer formed by fixing a cholesterol-type liquid crystal phase, and has multiple regions with different helical pitches of the cholesterol-type liquid crystal phase along the thickness direction.

[0126] Requirement 2: The optical anisotropic layer is an optical anisotropic layer formed by fixing the orientation state of the liquid crystal compound, and has multiple regions along the thickness direction in which the orientation direction of the liquid crystal compound has different tilt angles relative to the surface of the optical anisotropic layer.

[0127] Requirement 3: The optical anisotropic layer has a region along the thickness direction that fixes the orientation state of the liquid crystal compound and a region that fixes the state of the liquid crystal compound displaying an isotropic phase.

[0128] The following is a detailed description of each element.

[0129] <<Requirement 1>>

[0130] The optically anisotropic layer that satisfies requirement 1 is an optically anisotropic layer formed by fixing a cholesterol-type liquid crystal phase, and has multiple regions with different helical pitches of the cholesterol-type liquid crystal phase along the thickness direction.

[0131] exist Figure 3 The diagram shows one embodiment of an optical anisotropy layer that satisfies requirement 1.

[0132] Figure 3 The optically anisotropic layer 120 shown is an optically anisotropic layer formed using a liquid crystal compound (LC) and having a cholesterol-type liquid crystal phase fixed therein, and having a first region 120A and a second region 120B along the thickness direction. In the first region 120A and the second region 120B, the helical pitch of the cholesterol-type liquid crystal phase is different, with the helical pitch of the second region 120B being larger than that of the first region 120A. Therefore, the selective reflection center wavelength of the cholesterol-type liquid crystal phase originating from the first region 120A is different from that of the cholesterol-type liquid crystal phase originating from the second region 120B. For example, the optically anisotropic layer can be an optically anisotropic layer having regions along the thickness direction where a cholesterol-type liquid crystal phase that reflects blue light is fixed and regions that reflect green light are fixed, or it can be an optically anisotropic layer having regions along the thickness direction where a cholesterol-type liquid crystal phase that reflects green light is fixed and regions that reflect red light are fixed.

[0133] The optical anisotropic layer preferably has at least two regions selected from the group consisting of a region formed by fixing a cholesterol-type liquid crystal phase that reflects blue light, a region formed by fixing a cholesterol-type liquid crystal phase that reflects green light, and a region formed by fixing a cholesterol-type liquid crystal phase that reflects red light.

[0134] Furthermore, in this specification, the selection of the reflection center wavelength refers to setting the minimum value of the transmittance in the material (component) to be the object as T. min In the case of (%), the half-value transmittance expressed by the following formula is given: T 1 / 2 The average of the two wavelengths (%).

[0135] The formula for calculating half-value transmittance is: T 1 / 2 =100-(100-T) min )÷2

[0136] Furthermore, in the visible light spectrum, light with wavelengths above 420nm and below 500nm is blue light (B light), light with wavelengths above 500nm and below 600nm is green light (G light), and light with wavelengths above 600nm and below 700nm is red light (R light).

[0137] Furthermore, in this specification, the "fixed" state is the most typical and preferred state in which the orientation of the liquid crystal compound is maintained. It is not limited to this, but more preferably, it is a state in which there is no fluidity in the layer and the orientation shape is stably maintained without being changed by external field or external force within a temperature range of -30 to 70°C under more severe conditions.

[0138] Furthermore, in the optically anisotropic layer, the composition in the final layer no longer needs to exhibit liquid crystal properties.

[0139] Furthermore, in Figure 3 In the manner shown, the optical anisotropy layer 120 has two regions with different helical pitches of the cholesterol-type liquid crystal phase (in other words, two regions with different orientation states of the liquid crystal compound). However, the present invention is not limited to the above manner, and the optical anisotropy layer may have three or more regions with different helical pitches of the cholesterol-type liquid crystal phase.

[0140] The first region 120A and the second region 120B included in the optical anisotropy layer 120 exhibit selective reflection of circularly polarized light of either right-handed or left-handed circular polarization and transmission of circularly polarized light of the other direction.

[0141] The selective reflection center wavelength λ of a cholesterol-type liquid crystal phase depends on the helical pitch P (equal to the period of the helix) in the cholesterol-type liquid crystal phase and follows the relationship between the average refractive index n of the cholesterol-type liquid crystal phase and λ = n × P. From this equation, it can be seen that by adjusting the values ​​of n and P, the selective reflection center wavelength can be adjusted to a specified range.

[0142] In addition, in this specification, the term "helix direction" is sometimes used to refer to the twisting direction of the helix in the cholesterol-type liquid crystal phase. When the twisting direction (helix direction) of the helix in the cholesterol-type liquid crystal phase is to the right, it reflects right-handed circularly polarized light and transmits left-handed circularly polarized light; when the twisting direction is to the left, it reflects left-handed circularly polarized light and transmits right-handed circularly polarized light.

[0143] Furthermore, the helical orientation is preferably the same in regions with different helical pitches of the cholesterol-type liquid crystal phase in the optical anisotropic layer.

[0144] The helical pitch of a cholesterol-type liquid crystal phase depends on the type or concentration of the chiral reagent used with the liquid crystal compound; therefore, by adjusting these, the desired helical pitch can be obtained. Furthermore, methods for measuring the helix direction and pitch can be found in "An Introduction to Liquid Crystal Chemistry Experiments," edited by the Japan Liquid Crystal Society, published by Sigma in 2007, page 46, and in "Liquid Crystal Handbook," edited by Maruzen of the Liquid Crystal Handbook Editorial Committee, page 196.

[0145] There is no particular limitation on the thickness of the optical anisotropic layer that satisfies requirement 1, but it 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.

[0146] There are no particular limitations on the manufacturing method of the optical anisotropy layer that satisfies requirement 1, but a manufacturing method including the following steps 1A to 5A is preferred.

[0147] Step 1A: The step of forming a composition layer, said composition layer comprising at least a chiral reagent containing a photosensitive chiral reagent whose helical torsional force changes upon light irradiation, a liquid crystal compound having polymerizable groups, and a leveling agent.

[0148] Step 2A: A step of heat-treating the composition layer to orient the liquid crystal compounds in the composition layer to form a cholesterol-type liquid crystal phase.

[0149] Step 3A: After step 2A, under conditions where the oxygen concentration is 1% by volume or higher, the composite layer is subjected to an oxygen concentration of 300 mJ / cm. 2 The following process involves light irradiation for less than 50 seconds.

[0150] Step 4A: A step following Step 3A, in which the composition layer is heat-treated at a higher temperature than that used during light irradiation.

[0151] Step 5A: Following step 4A, a process is performed to cure the composition layer to form an optically anisotropic layer having regions with different orientation states of multiple liquid crystal compounds along the thickness direction.

[0152] As described later, in order to manufacture an optical anisotropic layer that satisfies requirement 1 above, the total content of chiral reagents in the composition layer (total content of all chiral reagents) is preferably more than 5.0% by mass relative to the total mass of the liquid crystal compound.

[0153] The steps of each of the above processes are described in detail below.

[0154] <Process 1A>

[0155] Step 1A is a step of forming a composition layer, which comprises at least a chiral reagent containing a photosensitive chiral reagent whose helical torsional force changes upon light irradiation, a liquid crystal compound having polymerizable groups, and a leveling agent. By performing this step, a composition layer subjected to the light irradiation treatment described later can be formed.

[0156] The following sections will first describe in detail the materials used in this process, and then describe the steps of the process in detail.

[0157] (Chiral reagents)

[0158] The composition layer of step 1A contains a chiral reagent that contains at least a photosensitive chiral reagent whose helical torsional force changes upon light irradiation. First, the photosensitive chiral reagent whose helical torsional force changes upon light irradiation will be described in detail.

[0159] In addition, the helical torsional force (HTP) of the chiral reagent is a factor representing the helical orientation capability expressed by the following formula (A).

[0160] Formula (A) HTP = 1 / (length of helical pitch (unit: μm) × concentration of chiral reagent relative to liquid crystal compound (mass%)) [μm -1 ]

[0161] The length of the helical pitch refers to the length of the pitch P (=the period of the helix) of the helical structure of the cholesterol-type liquid crystal phase, which can be measured using the method described on page 196 of the Liquid Crystal Handbook (published by MARUZEN GROUP).

[0162] A photosensitive chiral reagent (hereinafter, also referred to as "chiral reagent A") whose helical torsional force changes upon light irradiation can be either liquid crystal or non-liquid crystal. Chiral reagent A typically contains asymmetric carbon atoms. Alternatively, chiral reagent A can be an axially asymmetric compound or a surface asymmetric compound that does not contain asymmetric carbon atoms.

[0163] Chiral reagent A can be either a chiral reagent whose helical torsional force increases upon light irradiation or a chiral reagent whose helical torsional force decreases. Preferably, it is a chiral reagent whose helical torsional force decreases upon light irradiation.

[0164] Furthermore, in this specification, "increase and decrease of helical torsional force" refers to the increase or decrease when the initial (before light irradiation) helical direction of chiral reagent A is set to "positive". Therefore, when the helical torsional force continuously decreases and exceeds 0 due to light irradiation, and the helical direction becomes "negative" (i.e., when the helical direction is reversed from the initial (before light irradiation) helical direction), it also corresponds to "chiral reagent with decreased helical torsional force".

[0165] As a chiral reagent A, a so-called photoreactive chiral reagent can be cited. A photoreactive chiral reagent is a compound that has a chiral site and a photoreactive site whose structure changes upon light irradiation, for example, causing a significant change in the torsional force of a liquid crystal compound depending on the amount of irradiation.

[0166] Examples of photoreactive sites whose structure changes upon light irradiation include photochromic compounds (Kingo Uchida, Masahiro Irie, Chemical Industry, vol. 64, 640p, 1999; Kingo Uchida, Masahiro Irie, Fine Chemicals, vol. 28(9), 15p, 1999). Furthermore, these structural changes can be irreversible, occurring through light irradiation of the photoreactive site, such as decomposition, addition reactions, isomerization, racemization, [2+2] photocyclization, and dimerization. Additionally, chiral sites can include, for example, the asymmetric carbon described in Hiroyuki Nohira, General Chemical Studies, No. 22 Chemistry of Liquid Crystals, 73p: 1994.

[0167] Examples of chiral reagent A include, for instance, the photoreactive chiral reagents described in paragraphs 0044 to 0047 of Japanese Patent Application Publication No. 2001-159709, the optically active compounds described in paragraphs 0019 to 0043 of Japanese Patent Application Publication No. 2002-179669, the optically active compounds described in paragraphs 0020 to 0044 of Japanese Patent Application Publication No. 2002-179633, the optically active compounds described in paragraphs 0016 to 0040 of Japanese Patent Application Publication No. 2002-179670, the optically active compounds described in paragraphs 0017 to 0050 of Japanese Patent Application Publication No. 2002-179668, and the optically active compound described in paragraph 0018 of Japanese Patent Application Publication No. 2002-180051. The optically active compounds described in paragraphs ~0044, the optically active isosorbide derivatives described in paragraphs 0016 to 0055 of Japanese Patent Application Publication No. 2002-338575, the photoreactive optically active compounds described in paragraphs 0023 to 0032 of Japanese Patent Application Publication No. 2002-080478, the photoreactive chiral reagents described in paragraphs 0019 to 0029 of Japanese Patent Application Publication No. 2002-179681, the optically active compounds described in paragraphs 0022 to 0049 of Japanese Patent Application Publication No. 2002-302487, and the optically active compounds described in paragraphs 0015 to 0044 of Japanese Patent Application Publication No. 2002-3 The optically active polyesters described in paragraphs 0015-0050 of Japanese Patent Application Publication No. 38668; the binaphthyl derivatives described in paragraphs 0019-0041 of Japanese Patent Application Publication No. 2003-055315; the optically active fulgide compounds described in paragraphs 0008-0043 of Japanese Patent Application Publication No. 2003-073381; the optically active isosorbide derivatives described in paragraphs 0015-0057 of Japanese Patent Application Publication No. 2003-306490; the optically active isosorbide derivatives described in paragraphs 0015-0041 of Japanese Patent Application Publication No. 2003-313187; The optically active isosorbide derivatives described in paragraphs 0015-0049 of Japanese Patent Application Publication No. 2003-313188, the optically active isomannitol derivatives described in paragraphs 0015-0057 of Japanese Patent Application Publication No. 2003-313189, the optically active polyester / amides described in paragraphs 0015-0052 of Japanese Patent Application Publication No. 2003-313292, the optically active compounds described in paragraphs 0012-0053 of Japanese Patent Application Publication No. WO2018 / 194157, and the optically active compounds described in paragraphs 0020-0049 of Japanese Patent Application Publication No. 2002-179682, etc.

[0168] As the chiral reagent A, it is preferably a compound having at least a photoisomerization site, and the photoisomerization site is more preferably having a double bond capable of photoisomerization. As the aforementioned photoisomerization site having a double bond capable of photoisomerization, from the viewpoint of easy photoisomerization and a large difference in helical torsional force before and after light irradiation, a cinnamoyl site, a chalcone site, an azobenzene site, or a stilbene site is preferred; further from the viewpoint of low absorption of visible light, a cinnamoyl site, a chalcone site, or a stilbene site is more preferred. Furthermore, the photoisomerization site corresponds to the aforementioned photoreaction site whose structure changes upon light irradiation.

[0169] Furthermore, from the viewpoint that the initial (before light irradiation) helical torsion force is high and the change in helical torsion force based on light irradiation is superior, chiral reagent A preferably has a trans-type double bond that can undergo photoisomerization.

[0170] Furthermore, from the viewpoint that the initial (before light irradiation) helical torsion force is low and the change in helical torsion force based on light irradiation is superior, chiral reagent A preferably has a cis-type double bond capable of photoisomerization.

[0171] Chiral reagent A preferably has a structure selected from the binatidine moiety, the isosorbide moiety (a moiety derived from isosorbide), and the isomannitol moiety (a moiety derived from isomannitol). Furthermore, the binatidine moiety, the isosorbide moiety, and the isomannitol moiety refer to the following structures, respectively.

[0172] In the binaphthalene moiety structure, the parallel solid and dashed lines represent single or double bonds. Additionally, in the structures shown below, * indicates a bond position.

[0173] [Chemical Formula 4]

[0174]

[0175] Chiral reagent A may have polymerizable groups. There are no particular limitations on the type of polymerizable groups, but functional groups capable of undergoing addition polymerization are preferred, more preferably polymerizable olefinic unsaturated groups or cyclic polymerizable groups, and even more preferably (meth)acryloyl, vinyl, styrene or allyl.

[0176] As the chiral reagent A, the compound represented by formula (C) is preferred.

[0177] Formula (C)RLR

[0178] R independently represents a group having at least one part selected from the group consisting of cinnamyl, chalcone, azobenzene and stilbene.

[0179] L represents a divalent linker formed by removing two hydrogen atoms from the structure represented by formula (D) (a divalent linker formed by removing two hydrogen atoms from the above-mentioned binaphthyl moiety), a divalent linker represented by formula (E) (a divalent linker composed of the above-mentioned isosorbide moiety), or a divalent linker represented by formula (F) (a divalent linker composed of the above-mentioned isomannitol moiety).

[0180] In equations (E) and (F), * indicates the bonding position.

[0181] [Chemical Formula 5]

[0182]

[0183] In step 1A, at least the chiral reagent A described above can be used. Step 1A can be performed by using two or more chiral reagents A, or by using at least one chiral reagent A and at least one chiral reagent (hereinafter also referred to as "chiral reagent B") whose helical torsional force does not change upon light irradiation.

[0184] Chiral reagent B can be either liquid crystal or non-liquid crystal. Chiral reagent B typically contains asymmetric carbon atoms. Alternatively, chiral reagent B can be an axially asymmetric compound or a surface-asymmetric compound that does not contain asymmetric carbon atoms.

[0185] Chiral reagent B can have polymerizable groups. Examples of polymerizable groups that chiral reagent A can possess can be cited.

[0186] As chiral reagent B, known chiral reagents can be used.

[0187] Chiral reagent B is preferably a chiral reagent whose helix twists in the opposite direction to that of chiral reagent A. That is, for example, if the helix twisted by chiral reagent A is to the right, the helix twisted by chiral reagent B is to the left.

[0188] There are no particular limitations on the molar absorptivity of chiral reagent A and chiral reagent B, but the molar absorptivity at the wavelength of the light irradiated in step 3A described later (e.g., 365 nm) is preferably 100 to 100,000 L / (mol·cm), more preferably 500 to 50,000 L / (mol·cm).

[0189] The amounts of chiral reagent A and chiral reagent B in the composition layer can be appropriately set according to the characteristics of the optically anisotropic layer to be formed (e.g., retardation or wavelength dispersion). Furthermore, the twist angle of the liquid crystal compound in the optically anisotropic layer largely depends on the types and concentrations of chiral reagent A and chiral reagent B; therefore, by adjusting these, the orientation state of the liquid crystal compound can be controlled.

[0190] In step 1A, a chiral reagent is included in the composition layer to form a cholesterol-type liquid crystal phase in step 2A described later.

[0191] The total content of chiral reagents in the composition layer (total content of all chiral reagents) 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 even more preferably 6.0% by mass or more, relative to the total mass of the liquid crystal compound. There is no particular upper limit, but it is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0192] There is no particular limitation on the content of chiral reagent A in the chiral reagent, but from the viewpoint of easily controlling the orientation state of the liquid crystal compound, it is preferably 5 to 95% by mass relative to the total mass of the chiral reagent, and more preferably 10 to 90% by mass.

[0193] (Liquid crystal compound)

[0194] The composition layer of step 1A contains a liquid crystal compound having polymerizable groups.

[0195] There are no particular limitations on the type of liquid crystal compound. Generally, liquid crystal compounds can be classified according to their shape into rod-shaped (rod-shaped liquid crystal compounds) and disc-shaped (disc-shaped liquid crystal compounds). Furthermore, liquid crystal compounds can be classified into low-molecular-weight and high-molecular-weight types. High-molecular-weight compounds generally refer to compounds with a degree of polymerization of 100 or higher (Polymer Physics / Phase Transition Dynamics, Masao Doi, p. 2, Iwanami Shoten, 1992). In this invention, any liquid crystal compound can be used, but rod-shaped or disc-shaped liquid crystal compounds are preferred, and rod-shaped liquid crystal compounds are more preferred. Two or more rod-shaped liquid crystal compounds, two or more disc-shaped liquid crystal compounds, or mixtures of rod-shaped and disc-shaped liquid crystal compounds can be used.

[0196] In addition, as a rod-shaped liquid crystal compound, the rod-shaped liquid crystal compound described in claim 1 of Japanese Patent Application Publication No. 11-513019 or in paragraphs 0026 to 0098 of Japanese Patent Application Publication No. 2005-289980 is preferred.

[0197] As a disc-shaped liquid crystal compound, the disc-shaped 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 may be preferred.

[0198] There are no particular limitations on the types of polymerizable groups in the liquid crystal compound. Preferably, the functional groups are capable of addition polymerization reactions, more preferably polymerizable olefinic unsaturated groups or cyclic polymerizable groups, and even more preferably (meth)acryloyl, vinyl, styrene or allyl.

[0199] Furthermore, the optical anisotropic layer manufactured in this invention is a layer formed by fixing a liquid crystal compound with polymerizable groups (a rod-shaped liquid crystal compound or a disc-shaped liquid crystal compound with polymerizable groups) through polymerization or the like, and no longer needs to exhibit liquid crystal properties after being formed into a layer.

[0200] The content of the liquid crystal compound in the composition layer is not particularly limited, but from the viewpoint of easily controlling the orientation state of the liquid crystal compound, it is preferably 60% by mass or more, more preferably 70% by mass or more, relative to the total mass of the composition layer. There is no particular upper limit, but it is preferably 99% by mass or less, more preferably 97% by mass or less.

[0201] The definition of leveling agents is as described above.

[0202] The content of leveling agent in the composition layer is not particularly limited, but from the viewpoint of easily controlling the orientation state of the liquid crystal compound, it is preferably 0.010% by mass or more, more preferably 0.020% by mass or more, relative to the total mass of the composition layer. There is no particular upper limit, but it is preferably 5.000% by mass or less, more preferably 2.000% by mass or less.

[0203] (Other ingredients)

[0204] The composition layer may contain other components besides the chiral reagent, liquid crystal compound and leveling agent mentioned above.

[0205] For example, the composition layer may contain a polymerization initiator. When the composition layer contains a polymerization initiator, the polymerization of liquid crystal compounds with polymerizable groups is carried out more efficiently.

[0206] Known polymerization initiators can be cited as examples, including photopolymerization initiators and thermal polymerization initiators, with photopolymerization initiators being preferred. In particular, a photopolymerization initiator that is photosensitive to light irradiated in the subsequent step 5A is preferred.

[0207] The polymerization initiator preferably has a molar absorptivity of less than 0.1 times that of the wavelength of light irradiated in step 3A.

[0208] Furthermore, from the viewpoint of easily forming a specified optical anisotropic layer, the molar absorptivity of the polymerization initiator at the wavelength of light irradiation in step 3A is preferably 5000 L / (mol·cm) or less, more preferably 4000 L / (mol·cm) or less, and even more preferably 3000 L / (mol·cm) or less. There is no particular limitation on the lower limit; 0 L / (mol·cm) is preferred, but values ​​of 30 L / (mol·cm) or more are more common.

[0209] There is no particular limitation on the content of polymerization initiator in the composition layer, but it is preferably 0.01 to 20% by mass, more preferably 0.5 to 10% by mass, relative to the total mass of the composition layer.

[0210] The composition layer may contain a photosensitizer.

[0211] There are no particular restrictions on the types of photosensitizers; any well-known photosensitizers can be cited.

[0212] Furthermore, from the viewpoint of easily forming a specified optical anisotropic layer, the molar absorptivity of the photosensitizer at the wavelength of light irradiation in step 3A is preferably 5000 L / (mol·cm) or less, more preferably 4800 L / (mol·cm) or less, and even more preferably 4500 L / (mol·cm) or less. There is no particular limitation on the lower limit; 0 L / (mol·cm) is preferred, but values ​​of 30 L / (mol·cm) or more are more common.

[0213] There is no particular limitation on the content of photosensitizer in the composition layer, but it is preferably 0.01 to 20% by mass, more preferably 0.5 to 10% by mass, relative to the total mass of the composition layer.

[0214] The composition layer may contain polymerizable monomers different from those of liquid crystal compounds having polymerizable groups. Examples of polymerizable monomers include free radical polymerizable compounds and cationic polymerizable compounds, with multifunctional free radical polymerizable monomers being preferred. Examples of polymerizable monomers include those described in paragraphs 0018 to 0020 of Japanese Patent Application Publication No. 2002-296423.

[0215] The content of polymerizable monomers in the composition layer is not particularly limited, but is preferably 1 to 50% by mass relative to the total mass of the liquid crystal compound, more preferably 5 to 30% by mass.

[0216] The composition layer may contain a polymer. Examples of polymers include cellulose esters. Examples of cellulose esters include the cellulose ester described in paragraph 0178 of Japanese Patent Application Publication No. 2000-155216.

[0217] The content of polymer in the composition layer is not particularly limited, but it is preferably 0.1 to 10% by mass relative to the total mass of the liquid crystal compound, and more preferably 0.1 to 8% by mass.

[0218] In addition to the above, the composition layer may also contain additives (orientation control agents) that promote horizontal or vertical orientation so that the liquid crystal compound is in a horizontal or vertical orientation state.

[0219] (Substrate)

[0220] As described later, when forming the composition layer, it is preferable to form the composition layer on a substrate.

[0221] The substrate is a plate that supports the composite layer.

[0222] As a substrate, a transparent substrate is preferred. Furthermore, a transparent substrate refers to a substrate with a visible light transmittance of 60% or more, preferably 80% or more, and more preferably 90% or more.

[0223] There is no particular limitation on the thickness direction retardation value (Rth(550)) of the substrate at a wavelength of 550nm, but it is preferably -110 to 110nm, and more preferably -80 to 80nm.

[0224] The in-plane retardation value (Re(550)) of the substrate at a wavelength of 550nm is not particularly limited, but is preferably 0 to 50nm, more preferably 0 to 30nm, and even more preferably 0 to 10nm.

[0225] The preferred material for forming the substrate is a polymer with excellent optical transparency, mechanical strength, thermal stability, moisture shielding properties, and isotropy.

[0226] Examples of polymer films that can be used as substrates include cellulose acylate films (e.g., cellulose triacetate film (refractive index 1.48), cellulose diacetate film, cellulose acetate butyrate film, cellulose acetate propionate film), polyolefin films such as polyethylene and polypropylene, polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyethersulfone films, polypropylene films such as polymethyl methacrylate, polyurethane films, polycarbonate films, polysulfone films, polyether films, polymethylpentene films, polyetherketone films, (meth)acrylonitrile films, and films of polymers having an alicyclic structure (norbornene resins (ARTON: product name, manufactured by JSR Corporation.), amorphous polyolefins (ZEONEX: product name, manufactured by Zeon Corporation))).

[0227] The preferred material for the polymer film is triacetyl cellulose, polyethylene terephthalate, or a polymer with an alicyclic structure, with triacetyl cellulose being more preferred.

[0228] The substrate may contain various additives (e.g., optical anisotropy modifiers, wavelength dispersion modifiers, microparticles, plasticizers, UV protectants, degradation inhibitors, stripping agents, etc.).

[0229] The thickness of the substrate is not particularly limited, but it is preferably 10 to 200 μm, more preferably 10 to 100 μm, and even more preferably 20 to 90 μm. Furthermore, the substrate can be formed by stacking multiple sheets. To improve the adhesion between the substrate and the layers disposed on the substrate, surface treatments (e.g., glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, flame treatment) can be applied to the surface of the substrate.

[0230] Furthermore, an adhesive layer (base coat) can be applied to the substrate.

[0231] Furthermore, in order to impart sliding properties to the substrate during the transport process, or to prevent adhesion between the back side and the surface after winding, a polymer layer can be disposed on one side of the substrate. The polymer layer is formed by mixing inorganic particles with an average particle size of about 10 to 100 nm at a solid content mass ratio of 5 to 40%.

[0232] The substrate can also be a so-called pseudo-support. That is, after implementing the manufacturing method of the present invention, the substrate can be peeled off from the optical anisotropic layer.

[0233] Furthermore, the surface of the substrate can be directly rubbed. That is, a substrate that has already undergone rubbing treatment can be used. There are no particular restrictions on the direction of the rubbing treatment; the optimal direction should be appropriately selected based on the desired orientation of the liquid crystal compound.

[0234] Friction processing is a widely used method for liquid crystal alignment in LCDs (liquid crystal displays). Specifically, it involves rubbing the surface of a substrate in a specific direction using materials such as paper, gauze, felt, rubber, nylon fibers, or polyester fibers to achieve alignment.

[0235] An alignment film can be disposed on the substrate.

[0236] Oriented films can be formed by methods such as triboelectric treatment of organic compounds (preferably polymers), tilted evaporation of inorganic compounds, formation of layers with microgrooves, or accumulation of organic compounds (e.g., ω-trisanoic acid, dioctadecylmethylammonium chloride, methyl stearate) based on the Langmuir-Blodgett process (LB film).

[0237] Furthermore, it is also known that alignment films can generate alignment functions by applying an electric field, a magnetic field, or irradiation with light (preferably polarized light).

[0238] The orientation film is preferably formed by friction treatment of the polymer.

[0239] Examples of polymers included in the orientation film include methacrylate copolymers, styrene copolymers, polyolefins, polyvinyl alcohol and modified polyvinyl alcohol, poly(N-hydroxymethylacrylamide), polyesters, polyimides, vinyl acetate copolymers, carboxymethyl cellulose, and polycarbonates, as described in paragraph 0022 of Japanese Patent Application Publication No. 8-338913. Furthermore, silane coupling agents can also be used as polymers.

[0240] Preferably, the polymer is a water-soluble polymer (e.g., poly(N-hydroxymethylacrylamide), carboxymethyl cellulose, gelatin, polyvinyl alcohol, or modified polyvinyl alcohol), more preferably gelatin, polyvinyl alcohol, or modified polyvinyl alcohol, and even more preferably polyvinyl alcohol or modified polyvinyl alcohol.

[0241] As described above, the alignment film can be formed by coating a solution containing the polymer described above as an alignment film forming material and any additive (e.g., a crosslinking agent) onto a substrate, followed by heating and drying (to crosslink) and then rubbing.

[0242] (Steps of Process 1A)

[0243] In step 1A, a composition layer containing the above-mentioned components is formed, but the steps are not particularly limited. For example, examples include coating a composition (composition for forming an optical anisotropic layer) containing the above-mentioned chiral reagent, a liquid crystal compound having polymerizable groups, and a leveling agent onto a substrate, and performing a drying process as needed (hereinafter, also simply referred to as the "coating method"). Another method is to form a composition layer and transfer it onto a substrate. From the viewpoint of productivity, the coating method is preferred.

[0244] The coating method is described in detail below.

[0245] The composition used in the coating method includes the chiral reagent described above, a liquid crystal compound having polymerizable groups, a leveling agent, and other components used as needed (e.g., polymerization initiators, polymerization monomers, surfactants, and polymers).

[0246] The content of each component in the composition is preferably adjusted to the content of each component in the above-mentioned composition layer.

[0247] There are no particular restrictions on the coating method. Examples include wire rod coating, extrusion coating, direct gravure coating, reverse gravure coating, and die coating.

[0248] Additionally, if necessary, after applying the composition, a drying process can be performed on the coating film applied to the substrate. By performing the drying process, the solvent can be removed from the coating film.

[0249] In the composition layer, the leveling agent is easily distributed unevenly on the air interface side or the substrate side, thus achieving the distribution state of the leveling agent specified above.

[0250] There is no particular limitation on the thickness of the coating, but it is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, and even more preferably 0.5 to 10 μm.

[0251] <Process 2A>

[0252] Step 2A is as follows: The composition layer is subjected to heat treatment to orient the liquid crystal compounds in the composition layer to form a cholesterol-type liquid crystal phase. By performing this step, the liquid crystal compounds in the composition layer are oriented in a predetermined state.

[0253] The optimal conditions for heat treatment are selected based on the liquid crystal compound used.

[0254] Among these, the heating temperatures are mostly between 25 and 250°C, even more so between 40 and 150°C, and even more so between 50 and 130°C.

[0255] The heating time is typically 0.1 to 60 minutes, with 0.2 to 5 minutes being more common.

[0256] The orientation state of the liquid crystal compound obtained through step 2A changes according to the helical torsion force of the chiral reagent mentioned above.

[0257] The absolute value of the helical torsional force of the chiral reagent in the composition layer formed by step 1A is preferably 10 μm. -1 The above, more preferably 15μm -1 The above is further preferred to be 20μm. -1 That's all. There's no specific upper limit, but 250μm is acceptable. -1 The following situations are more common, 200μm -1 The following situations are more common.

[0258] Furthermore, when the composition contains two or more chiral agents, the absolute value of the weighted average helical torsional force of the chiral agents in the composition layer formed by step 1A is preferably within the above-mentioned range.

[0259] Furthermore, the weighted average helical torsional force of the chiral reagent represents the sum of the values ​​obtained by dividing the product of the helical torsional force of each chiral reagent contained in the composition layer and the concentration (mass%) of each chiral reagent in the composition layer by the total concentration (mass%) of the chiral reagents in the composition layer when the composition contains two or more chiral reagents. For example, when two chiral reagents (chiral reagent X and chiral reagent Y) are used simultaneously, it is represented by the following formula (B).

[0260] Equation (B) Weighted average helical torsional force (μm) -1 ) = (helical torsional force of chiral reagent X (μm) -1 × Concentration (mass%) of chiral reagent X in the composition layer + Helical torsion force (μm) of chiral reagent Y -1 () × Concentration (mass%) of chiral reagent Y in the composition layer / (Concentration (mass%) of chiral reagent X in the composition layer + Concentration (mass%) of chiral reagent Y in the composition layer)

[0261] In equation (B) above, when the chiral reagent has a right-handed helix, its torsional force is set to a positive value. Conversely, when the chiral reagent has a left-handed helix, its torsional force is set to a negative value. That is, for example, when the torsional force is 10 μm... -1 In the case of chiral reagents, when the helical direction of the helix twisted by the aforementioned chiral reagent is right-handed, the helical torsional force is expressed as 10 μm. -1 On the other hand, when the helix twisted by the aforementioned chiral reagent is left-handed, the torsional force is expressed as -10 μm. -1 .

[0262] <Process 3A>

[0263] Step 3A is as follows: After step 2A, the composition layer is subjected to an oxygen concentration of 1% by volume or higher at 300 mJ / cm². 2 The following involves light exposure for no more than 50 seconds. The mechanism of this process will now be described using the accompanying drawings. Furthermore, Figure 4 The method shown corresponds to the way that liquid crystal compounds (LCs) form cholesterol-type liquid crystal phases.

[0264] like Figure 4 As shown, in process 3A, under conditions where the oxygen concentration is 1% by volume or higher, the direction from the side of the substrate 10 opposite to the side of the composition layer 122 is ( Figure 4 The direction of the hollow arrow in the image is used for illumination. Additionally, in... Figure 4 In this process, light irradiation is performed from the substrate 10 side, but it can also be performed from the composition layer 122 side.

[0265] At this point, if we compare the lower region 122A on the substrate 10 side of the composition layer 122 with the upper region 122B on the opposite side of the substrate 10 side, the surface of the upper region 122B is on the air side, therefore the oxygen concentration in the upper region 122B is high, and the oxygen concentration in the lower region 122A is low. Therefore, if the composition layer 122 is irradiated with light, the liquid crystal compound is easily polymerized in the lower region 122A, and the orientation state of the liquid crystal compound is fixed. In addition, chiral reagent A is also present in the lower region 122A, and the chiral reagent A is also photosensitive, causing a change in the helical torsion force. However, since the orientation state of the liquid crystal compound is fixed in the lower region 122A, even if the heat treatment step 4A of the light-irradiated composition layer described later is performed, no change in the orientation state of the liquid crystal compound will occur.

[0266] Furthermore, due to the high oxygen concentration in the upper region 122B, 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 122B, and therefore, the helical torsion force changes upon photosensitive reaction to chiral reagent A. Thus, if step 4A is performed later, the orientation state of the liquid crystal compound changes along with the altered helical torsion force.

[0267] That is, by performing step 3A, 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.

[0268] Step 3A is performed under conditions where the oxygen concentration is 1% by volume or more. From the viewpoint that regions with different orientation states are more likely to form liquid crystal compounds in the optical anisotropy layer, the oxygen concentration is preferably 2% by volume or more, and more preferably 5% by volume or more. There is no particular upper limit, but 100% by volume can be cited as an example.

[0269] The light irradiation time in step 3A is 50 seconds or less. From the viewpoint of easily forming the specified optical anisotropy layer and from the viewpoint of productivity, it is preferably 30 seconds or less, and more preferably 10 seconds or less. There is no particular limitation on the lower limit, but from the viewpoint of curing the liquid crystal compound, it is preferably 0.1 seconds or more, and more preferably 0.2 seconds or more.

[0270] The light irradiation dose in process 3A is 300 mJ / cm. 2 From the viewpoints of ease of forming a specified optical anisotropy layer and productivity, 250 mJ / cm is preferred. 2 The following is more preferably 200 mJ / cm2 The 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.

[0271] In addition, the light irradiation in step 3A is preferably carried out at 15 to 70°C (preferably 25 to 50°C).

[0272] 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.

[0273] <Process 4A>

[0274] 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.

[0275] The mechanism of this process will be described below using the accompanying drawings.

[0276] As mentioned above, if for Figure 4 In step 3A of the composition layer 122 shown, the orientation state of the liquid crystal compound is fixed in the lower region 122A, while polymerization of the liquid crystal compound is difficult to occur in the upper region 122B, 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 122B. 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 122B changes. This will be explained in more detail.

[0277] Furthermore, in the following description, the case in which the composition layer 122 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.

[0278] Light is irradiated in the upper region 122B of this state, such as... Figure 6 As shown, when the helical torsional force of chiral reagent A decreases according to the amount of light irradiation, the helical torsional force of the chiral reagent in the upper region 122B decreases.

[0279] Therefore, if the composition layer 122 after process 3A, where the helical torsional force changes, is subjected to heat treatment to promote the reorientation of the liquid crystal compound, then as... Figure 5 As shown, in the upper region 122B, the helical pitch of the cholesterol-type liquid crystal layer increases.

[0280] On the other hand, as described above, in the lower region 122A of the composition layer 122, the liquid crystal compound is polymerized during step 3A and the orientation state of the liquid crystal compound is fixed, so the reorientation of the liquid crystal compound is not performed.

[0281] As described above, by performing step 4A, multiple cholesterol-type liquid crystal phases with different helical pitches are formed along the thickness direction of the composition layer.

[0282] In addition, in the above Figure 4 and Figure 5 The text describes a method of using a chiral reagent whose helical torsional force decreases upon light irradiation as chiral reagent A, but it is not limited to this method. For example, a chiral reagent whose helical torsional force increases upon light irradiation can be used as chiral reagent A.

[0283] Furthermore, in the above Figure 4 and Figure 5 The text describes the use of a left-handed chiral reagent as chiral reagent A, but it is not limited to this method. For example, a right-handed chiral reagent can be used as chiral reagent A.

[0284] Furthermore, in the above Figure 4 and Figure 5 The text describes a method using only one chiral reagent A, but it is not limited to this method. For example, it can use two chiral reagents A, or it can use both chiral reagent A and chiral reagent B simultaneously.

[0285] The heat treatment is carried out at a higher temperature than that under light irradiation.

[0286] The temperature difference between the heat treatment and the light irradiation temperature is preferably 5°C or more, more preferably 10 to 110°C, and even more preferably 20 to 110°C.

[0287] The preferred temperature for heat treatment is higher than the temperature during light irradiation and is a temperature that orients the unfixed liquid crystal compounds in the composition layer. More specifically, 40–250°C is more common, 50–150°C is even more common, temperatures exceeding 50°C but below 150°C are even more common, and temperatures of 60–130°C are particularly common.

[0288] The heating time is typically between 0.01 and 60 minutes, with 0.03 to 5 minutes being more common.

[0289] Furthermore, there is no particular limitation on the absolute value of the helical torsional force of the chiral reagent in the composition layer after light irradiation, but the absolute value of the difference between the helical torsional force of the chiral reagent in the composition layer after light irradiation and the helical torsional force before light irradiation is preferably 0.05 μm. -1 More preferably, the micrometer size is 0.05–10.0 μm. -1 More preferably, it is 0.1–10.0 μm. -1 .

[0290] Furthermore, when the composition contains two or more chiral reagents, the absolute value of the difference between the weighted average helical torsion force of the chiral reagents in the composition layer after light irradiation and the weighted average helical torsion force before light irradiation is preferably 0.05 μm. -1 More preferably, the micrometer size is 0.05–10.0 μm. -1 More preferably, it is 0.1–10.0 μm. -1 .

[0291] <Process 5A>

[0292] Step 5A is as follows: After step 4A, the composition layer is cured to form an optically anisotropic layer having multiple regions with different orientation states of liquid crystal compounds along the thickness direction. By performing this step, the orientation state of the liquid crystal compounds in the composition layer is fixed, resulting in the formation of a predetermined optically anisotropic layer. Furthermore, by performing this step, an optically anisotropic layer can be formed with multiple regions having different helical pitches of the cholesterol-type liquid crystal phase along the thickness direction, where the cholesterol-type liquid crystal phase is fixed. In many cases, the length of the helical pitch in each region is constant. That is, by performing this step, an optically anisotropic layer can be formed with multiple regions having different helical pitches of the cholesterol-type liquid crystal phase along the thickness direction, and where the helical pitch in each region is constant.

[0293] There are no particular limitations on the curing method; examples include light curing and heat curing. Among these, light irradiation is preferred, and ultraviolet irradiation is more preferred.

[0294] Ultraviolet radiation is achieved using light sources such as ultraviolet lamps.

[0295] There are no particular limitations on the amount of light (e.g., ultraviolet radiation), but it is generally preferred to be 100–800 mJ / cm². 2 about.

[0296] There are no particular restrictions on the environment during light irradiation; it can be carried out in air or in a non-active environment. In particular, light irradiation is preferably carried out under conditions where the oxygen concentration is less than 1% by volume.

[0297] When performing photocuring as a curing process, there are no particular restrictions on the temperature conditions during photocuring, as long as the temperature is sufficient to maintain the orientation state of the liquid crystal compound in step 4A. The temperature difference between the heating treatment temperature in step 4A and the temperature during photocuring is preferably within 100°C, and more preferably within 80°C.

[0298] In addition, it is preferable that the temperature of the heat treatment in step 4A is the same as the temperature during the photocuring treatment or a lower temperature during the photocuring treatment.

[0299] Furthermore, in Figure 5 In the illustrated configuration, the optical anisotropic layer has two regions with different orientation states of the liquid crystal compounds. However, the present invention is not limited to the above configuration, and the optical anisotropic layer may have three or more regions with different orientation states of the liquid crystal compounds. As described above, an optical anisotropic layer having three or more regions with different orientation states of the liquid crystal compounds can be formed, for example, by performing step 3A multiple times by changing the conditions.

[0300] Examples of optically anisotropic layers, as described above, include regions along the thickness direction formed by fixing a cholesterol-type liquid crystal phase that reflects blue light, a region formed by fixing a cholesterol-type liquid crystal phase that reflects green light, and a region formed by fixing a cholesterol-type liquid crystal phase that reflects red light.

[0301] <<Requirement 2>>

[0302] The optical anisotropic layer that satisfies requirement 2 is an optical anisotropic layer formed by fixing the orientation state of a liquid crystal compound, and has multiple regions along the thickness direction in which the orientation direction of the liquid crystal compound has different tilt angles relative to the surface of the optical anisotropic layer.

[0303] exist Figure 7 The diagram shows one embodiment of an optical anisotropy layer that satisfies requirement 2.

[0304] Figure 7 The optical anisotropic layer 220 shown is an optical anisotropic layer formed by fixing the orientation state of the liquid crystal compound LC, and has a first region 220A and a second region 220B along the thickness direction. The first region 220A is a region formed by fixing the orientation state of the liquid crystal compound in parallel orientation (horizontal orientation), and the second region 220B is a region formed by fixing the orientation state of the liquid crystal compound in vertical orientation (homeotropic alignment).

[0305] In this specification, parallel orientation refers to the state in which the molecular axes of a liquid crystal compound (e.g., the long axis in the case of rod-shaped liquid crystal compounds) are aligned horizontally and in the same orientation relative to the layer surface (optical uniaxiality).

[0306] The term "horizontal" is not strictly required to be horizontal, but rather refers to an orientation in which the average molecular axis of the liquid crystal compound within the layer forms an angle of inclination of less than 20 degrees with the surface of the layer.

[0307] Furthermore, the same orientation is not strictly required to be the same orientation. Rather, it means that when the orientation of the slow axis is measured at any 20 locations in the plane, the maximum difference between the orientations of the slow axis at the 20 locations (the difference between the two slow axis orientations with the largest difference among the 20 slow axis orientations) is less than 10°.

[0308] Furthermore, in this specification, vertical orientation refers to the state in which the molecular axes of the liquid crystal compound (for example, the long axis in the case of rod-shaped liquid crystal compounds) are perpendicular to the layer surface and aligned in the same orientation (optical uniaxiality).

[0309] The term "vertical" does not strictly require absolute verticality, but rather indicates an orientation in which the tilt angle between the average molecular axis of the liquid crystal compound within the layer and the normal to the surface of the layer is less than 20 degrees.

[0310] Furthermore, the same orientation is not strictly required to be the same orientation. Rather, it means that when the orientation of the molecular axis of the liquid crystal compound is measured at any 20 locations, the maximum difference among the orientations of the molecular axes of the liquid crystal compounds at the 20 locations (the difference between the orientations of the two liquid crystal compounds with the largest differences among the orientations of the molecular axes of the 20 liquid crystal compounds) is less than 10°.

[0311] When the thickness of the first region 220A is set to d1 and the in-plane refractive index anisotropy of the first region 220A measured at a wavelength of 550 nm is set to Δn1, from the viewpoint that the optical anisotropy layer can be preferably applied to a circular polarizer or the viewpoint that the optical anisotropy layer can be preferably applied to an optical compensation plate of a liquid crystal display device, the first region preferably satisfies the following formula (1-1).

[0312] Equation (1-1) 100nm≤Δn1d1≤180nm

[0313] More preferably, equation (1-2) is satisfied.

[0314] Equation (1-2) 110nm≤Δn1d1≤170nm

[0315] Furthermore, when the thickness of the second region 220B is set to d2 and the in-plane refractive index anisotropy of the second region 220B measured at a wavelength of 550nm is set to Δn2, from the viewpoint that the optical anisotropy layer can be preferably applied to a circular polarizer or that light leakage in the tilt direction can be reduced when used as an optical compensation plate for a liquid crystal display device, the second region 220B preferably satisfies the following formula (2-1).

[0316] Equation (2-1) 0nm≤Δn2d2≤30nm

[0317] Among them, it is more preferable to satisfy equation (2-2).

[0318] Equation (2-2) 0nm≤Δn2d2≤20nm

[0319] The thickness retardation of the second region 220B at a wavelength of 550 nm is preferably -150 to -20 nm, more preferably -120 to -20 nm.

[0320] The optical anisotropy layer that satisfies requirement 2 preferably represents reverse wavelength dispersion.

[0321] That is, the in-plane delay Re(450) measured at a wavelength of 450 nm, the in-plane delay Re(550) measured at a wavelength of 550 nm, and the in-plane delay Re(650) measured at a wavelength of 650 nm are preferably in the relationship Re(450)≤Re(550)≤Re(650).

[0322] There are no particular limitations on the optical properties of the optical anisotropy layer that meets requirement 2, but it is preferred to function as a λ / 4 plate or as an optical compensation plate for a liquid crystal display device.

[0323] A λ / 4 plate is a plate that has the function of converting linearly polarized light of a specific wavelength into circularly polarized light (or converting circularly polarized light into linearly polarized light), and refers to a plate (optical anisotropic layer) whose in-plane retardation Re(λ) at a specific wavelength λnm satisfies Re(λ)=λ / 4.

[0324] This formula can be implemented at any wavelength in the visible light region (e.g., 550 nm), but preferably the in-plane delay Re(550) at a wavelength of 550 nm satisfies the relationship 100 nm ≤ Re(550) ≤ 180 nm.

[0325] In the above-described manner, an optically anisotropic layer having regions along the thickness direction in which the orientation of vertically oriented liquid crystal compounds is fixed and regions in which the orientation of parallel-oriented liquid crystal compounds is fixed is described in detail. However, the method is not limited to this method as long as the optically anisotropic layer contains multiple regions in which the orientation direction of the liquid crystal compounds has different tilt angles relative to the layer surface.

[0326] For example, when the liquid crystal compound is rod-shaped, its orientation states can include nematic orientation (forming a nematic phase), smectic orientation (forming a smectic phase), cholesterol orientation (forming a cholesterol phase), and mixed orientation. When the liquid crystal compound is disc-shaped, its orientation states can include nematic orientation, columnar orientation (forming a columnar phase), and cholesterol orientation.

[0327] More specifically, the optical anisotropy layer can be an optical anisotropy layer having a region for fixing the orientation state of tilted liquid crystal compounds and a region for fixing the orientation state of parallel-oriented liquid crystal compounds.

[0328] There are no particular limitations on the manufacturing method of the optical anisotropy layer that satisfies requirement 2, but a manufacturing method including the following steps 1B to 5B is preferred.

[0329] Step 1B: The step of forming a composition layer, said composition layer comprising a photosensitive compound whose polarity changes upon light irradiation, a liquid crystal compound having polymerizable groups, and a leveling agent.

[0330] Step 2B: A step of heat-treating the composition layer to orient the liquid crystal compounds in the composition layer.

[0331] Step 3B: After step 2B, under conditions where the oxygen concentration is 1% by volume or higher, the composition layer is subjected to 300 mJ / cm 2 The following process involves light irradiation for less than 50 seconds.

[0332] Step 4B: A step following Step 3B, in which the composition layer is heat-treated at a higher temperature than that used during light irradiation.

[0333] Step 5B: Following step 4B, a process is performed to cure the composition layer to form an optically anisotropic layer having regions with different orientation states of multiple liquid crystal compounds along the thickness direction.

[0334] In this manufacturing method, as described later, a photosensitive compound whose polarity changes upon exposure to light is used.

[0335] The steps of each of the above processes are described in detail below.

[0336] <Process 1B>

[0337] Step 1B is a step of forming a composition layer comprising a photosensitive compound whose polarity changes upon light irradiation and a liquid crystal compound having polymerizable groups. By performing this step, a composition layer subjected to the light irradiation treatment described later can be formed.

[0338] The definitions and contents of the liquid crystal compounds and leveling agents contained in the composition layer are as described in step 1A.

[0339] Furthermore, as described in step 1A above, the composition layer may contain other components.

[0340] (Photosensitive compounds whose polarity changes upon exposure to light)

[0341] The composition layer of step 1B contains a photosensitive compound whose polarity changes upon light irradiation (hereinafter also referred to as "specific photosensitive compound").

[0342] A photosensitive compound whose polarity changes upon light irradiation is a compound whose polarity changes before and after light irradiation. As described later, if a composition layer containing such a specific photosensitive compound is subjected to light irradiation in step 1B, the polarity of the specific photosensitive compound changes in the air-side region of the composition layer, and thus, during step 4B, the orientation direction of the liquid crystal compound is tilted or perpendicular to the layer surface as its polarity changes.

[0343] The change in polarity of a specific photosensitive compound can be either a change in hydrophilicity or a change in hydrophobicity. From the viewpoint of easily forming a liquid crystal compound whose orientation direction is tilted or perpendicular to the layer surface, a change in hydrophilicity is preferred.

[0344] As a specific photosensitive compound that becomes hydrophilic upon light irradiation, a compound having a group that generates a hydrophilic group upon light irradiation is preferred. The type of hydrophilic group is not particularly limited and can be any of cationic, anionic, and nonionic groups; more specifically, examples include carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, and hydroxyl groups.

[0345] The specific photosensitive compound preferably has fluorine atoms or silicon atoms. When the specific photosensitive compound has the above-mentioned atoms, the specific photosensitive compound is easily and unevenly distributed near the surface of the composition layer, thereby easily forming the desired optical anisotropy layer.

[0346] The preferred photosensitive compound is the compound represented by formula (X).

[0347] [Chemical Formula 6]

[0348]

[0349] In the above formula (X),

[0350] T represents an aromatic hydrocarbon group with an n+m valence.

[0351] Sp represents a single bond or a divalent linker.

[0352] Hb represents a fluorinated alkyl group with 4 to 30 carbon atoms.

[0353] m represents an integer from 1 to 4.

[0354] n represents an integer from 1 to 4.

[0355] A represents the group represented by the following formula (Y).

[0356] [Chemical Formula 7]

[0357]

[0358] In the above formula (Y),

[0359] R1 to R5 each independently represent a hydrogen atom or a monovalent substituent.

[0360] * indicates the bonding site.

[0361] Furthermore, in the above formula (X), when there are multiple Sp, multiple Hb, or multiple A, the multiple Sp can be the same as each other, the multiple Hb can be the same as each other, or the multiple A can be different from each other.

[0362] In the above formula (X), T represents an aromatic hydrocarbon group with an n+m valence.

[0363] There are no particular limitations as long as the aromatic hydrocarbon group is obtained by removing n+m hydrogen atoms from an aromatic hydrocarbon ring, but it is preferred to have 6 to 22 carbon atoms, more preferably 6 to 14, and even more preferably 6 to 10. The aromatic hydrocarbon group is particularly preferred to be a benzene ring.

[0364] In addition to the groups represented by -Sp-Hb and -C(=O)OA, the aforementioned aromatic hydrocarbon groups may also have substituents. Examples of substituents include alkyl groups (e.g., alkyl groups with 1 to 8 carbon atoms), alkoxy groups (e.g., alkoxy groups with 1 to 8 carbon atoms), halogen atoms (e.g., fluorine, chlorine, bromine, and iodine atoms), cyano groups, and acyloxy groups (e.g., acetoxy groups).

[0365] In the above formula (X), Sp represents a single bond or a divalent linking group, preferably a divalent linking group.

[0366] There are no particular limitations on the aforementioned divalent linking group, but it is preferably selected from the group consisting of straight-chain or branched alkylene groups (preferably with 1 to 20 carbon atoms, more preferably with 1 to 10 carbon atoms, and even more preferably with 1 to 6 carbon atoms), straight-chain or branched alkenyl groups (preferably with 2 to 20 carbon atoms, more preferably with 2 to 10 carbon atoms, and even more preferably with 2 to 6 carbon atoms), straight-chain or branched alkyne groups (preferably with 2 to 20 carbon atoms, more preferably with 2 to 10 carbon atoms, and even more preferably with 2 to 6 carbon atoms), or groups in which one or more of the -CH2- groups are substituted with the "divalent organic group" shown below.

[0367] As the aforementioned divalent linking group, from the viewpoint of further improving solubility, it is preferably an alkylene group with 1 to 10 carbon atoms that has one or more -CH2-substituted with a "divalent organic group" as shown below.

[0368] (Divalent organic group)

[0369] Examples of divalent organic groups include -O-, -S-, -C(=O)-, -C(=O)O-, -OC(=O)-, -C(=O)S-, -SC(=O)-, -NR6C(=O)-, or -C(=O)NR6-. From the viewpoint of further hydrophilization, -O-, -S-, -C(=O)-, -C(=O)O-, -OC(=O)-, -C(=O)S-, or SC(=O)- are more preferred, and -O-, -C(=O)-, -C(=O)O-, or OC(=O)- are even more preferred, and -O-, -C(=O)O-, or OC(=O)- are particularly preferred.

[0370] Furthermore, R6 above represents an alkyl group having 1 to 6 hydrogen atoms or carbon atoms.

[0371] Furthermore, when the aforementioned divalent linking group includes the aforementioned divalent organic group, it is preferable that the aforementioned divalent organic groups are not adjacent to each other.

[0372] In the above formula (X), Hb represents a fluorinated alkyl group with 4 to 30 carbon atoms.

[0373] Hb is preferably composed of 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms. The fluorinated alkyl group can be a perfluoroalkyl group in which all hydrogen atoms are replaced by fluorine atoms, or a fluoroalkyl group in which some hydrogen atoms are replaced by fluorine atoms. Furthermore, the fluorinated alkyl group can be any of the following: chain-like, branched, or cyclic, but is preferably chain-like or branched, more preferably chain-like.

[0374] As a fluorinated alkyl group, the structure of a perfluoroalkyl group is preferred.

[0375] In the above formula (X), the preferred manner of the group represented by -Sp-Hb is illustrated below.

[0376] Additionally, in the following examples, * indicates the connection position with T.

[0377] (C p F 2p+1 )-(CH2) q -O-(CH2) r -O-*

[0378] (C p F 2p+1 )-(CH2) q -C(=O)O-(CH2) r -C(=O)O-*

[0379] (C p F 2p+1 )-(CH2) q -OC(=O)-(CH2) r -C(=O)O-*

[0380] (C p F 2p+1 )-(CH2) q -OC(=O)-(CH2) r -OC(=O)-*

[0381] In the groups represented by -Sp-Hb above, p is preferably 4 to 30, more preferably 4 to 20, and even more preferably 4 to 10. q is preferably 0 to 6, more preferably 0 to 4, and even more preferably 0 to 3. r is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3.

[0382] Furthermore, the total number of carbon atoms in the portion excluding the perfluorinated group is preferably 10 or less.

[0383] In the above formula (X), n and m independently represent integers from 1 to 4.

[0384] From the viewpoint of further hydrophilization, n is preferably 2 or more. m is preferably 1 to 3, and more preferably 2.

[0385] In the above formula (X), A represents the group represented by the above formula (Y).

[0386] The following is an explanation of equation (Y).

[0387] In the above formula (Y), R1 to R5 independently represent a hydrogen atom or a monovalent substituent. There are no particular restrictions on the monovalent substituents represented by R1 to R5.

[0388] Examples of monovalent substituents represented by R1 to R4 include halogen atoms (e.g., fluorine, chlorine, bromine, and iodine atoms), hydroxyl groups, cyano groups, and substituted or unsubstituted amino groups (consisting of -N(R)). A )2 means 2 R A Each of these groups independently represents a hydrogen atom or a monovalent organic group (as a monovalent organic group, for example, an alkyl group having 1 to 5 carbon atoms). It also represents an alkoxy group having 1 to 8 carbon atoms (e.g., a methoxy or ethoxy group), or an amide group having 2 to 8 carbon atoms (e.g., a -N(R) group). B )C(=O)R C (R B R represents a hydrogen atom or a monovalent organic group (as a monovalent organic group, for example, an alkyl group having 1 to 5 carbon atoms). C This indicates a monovalent organic group (e.g., an alkyl group having 1 to 5 carbon atoms). It can also be represented by -C(=O)N(R). D )2(2 R D Each of these groups independently represents a hydrogen atom or a monovalent organic group (e.g., an alkyl group having 1 to 5 carbon atoms). Other groups include alkoxy carbonyl groups having 2 to 8 carbon atoms (e.g., -C(=O)OCH3), acyloxy groups having 2 to 8 carbon atoms (e.g., -OC(=O)CH3), and -Sp groups. A -Hb A .

[0389] The above Sp A and the above-mentioned Hb A The meanings of Sp and Hb in equation (X) above are the same, and their preferred methods are also the same. Furthermore, in equation (Y), the multiple representations of -Sp in R1 to R4... A -Hb A In the case where there are multiple Sp A Hb and the existence of multiple Hb A They can be the same or different.

[0390] Preferably, R1 to R4 are hydrogen atoms, halogen atoms, hydroxyl groups, cyano groups, alkoxy groups, -NH2, -NH(CH3), -N(CH3)2, -C(=O)OCH3, -OC(=O)CH3, -NHC(=O)CH3, -N(CH3)C(=O)CH3 or -Sp, respectively. A -Hb A .

[0391] In particular, from the viewpoint of further accelerating the decomposition rate of the compound represented by the exposure-based formula (X) and further hydrophilicating it, and / or further improving its orientation, it is more preferable that R1 to R4 are independently -OCH3 or Sp. A -Hb A In the case of -OCH3, there is a tendency for the structure to contain ether oxygen (especially at the position bonded to the benzene ring in formula (Y)), thus further accelerating the decomposition rate of the compound represented by formula (X) based on exposure and further hydrophilization. On the other hand, in the case of -Sp... A -Hb A In this case, there is a tendency to: via Hb A The presence of [something] further enhances orientation. Additionally, in Sp... A In the case where its structure contains ether oxygen (especially in Sp...) A In and Hb A 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 can be obtained in the same way as the -OCH3 above.

[0392] 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 .

[0393] 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.

[0394] 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).

[0395] 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.

[0396] 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, it has the structure represented by the following formula (Z).

[0397] Formula (Z)(C) p F 2p+1 )-(CH2) q -O-(CH2) r -O-*

[0398] In formula (Z), p is preferably 4 to 30, more preferably 4 to 20, and even more preferably 4 to 10. q is preferably 0 to 5, more preferably 0 to 4, and even more preferably 0 to 3. r is preferably 1 to 5, more preferably 1 to 4, and even more preferably 1 to 3.

[0399] In the above formula (Y), R5 is preferably a hydrogen atom, methyl, ethyl or aromatic group.

[0400] There are no particular limitations on the aromatic group, but it is preferred to have 6 to 14 carbon atoms, more preferably 6 to 10, and even more preferably phenyl.

[0401] From the viewpoint of further hydrophilization to further accelerate the decomposition rate of the compound represented by the exposure-based formula (X), the above-mentioned R5 is preferably a methyl, ethyl, or aromatic group, more preferably an ethyl or aromatic group, and even more preferably an aromatic group.

[0402] Furthermore, in the above formula (Y), * represents the bonding site with C(=O)O- in the above formula (X).

[0403] The compound represented by the above formula (X) can be a compound with symmetrical molecular structure or a compound without symmetrical structure. In addition, the symmetry mentioned here means any one of point symmetry, line symmetry, and rotational symmetry, and the asymmetry means not corresponding to any one of point symmetry, line symmetry, and rotational symmetry.

[0404] Furthermore, in the case where multiple Sp, Hb, or A are present in the compound represented by the above formula (X), the multiple Sp, the multiple Hb, or the multiple A may be the same or different from each other.

[0405] The content of a specific photosensitive compound in the composition layer can be appropriately set according to the characteristics of the optically anisotropic layer to be formed (e.g., retardation or wavelength dispersion).

[0406] From the viewpoint that it is easier to form an optically anisotropic layer with a specified structure, the content of the specific photosensitive compound relative to the total mass of the liquid crystal compound is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass.

[0407] In step 1A, a composition layer containing the above-mentioned components is formed, but the steps are not particularly limited. For example, examples include a method of coating a composition containing the above-mentioned specific photosensitive compound, a liquid crystal compound having polymerizable groups, and a leveling agent onto a substrate, and then performing a drying process as needed (hereinafter also simply referred to as the "coating method"), and another method of forming a composition layer and transferring it onto a substrate. From the viewpoint of productivity, the coating method is preferred.

[0408] The coating method is described in detail below.

[0409] The composition used in the coating method includes the aforementioned specific photosensitive compound, a liquid crystal compound having polymerizable groups, a leveling agent, and other components used as needed (e.g., polymerization initiators, polymerizable monomers, surfactants, and polymers).

[0410] The content of each component in the composition is preferably adjusted to the content of each component in the above-mentioned composition layer.

[0411] There are no particular restrictions on the coating method. Examples include wire rod coating, extrusion coating, direct gravure coating, reverse gravure coating, and die coating.

[0412] Additionally, if necessary, after applying the composition, a drying process can be performed on the coating film applied to the substrate. By performing the drying process, the solvent can be removed from the coating film.

[0413] There is no particular limitation on the thickness of the coating, but it is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, and even more preferably 0.5 to 10 μm.

[0414] <Process 2B>

[0415] Step 2B involves heat-treating the composition layer to orient the liquid crystal compound within it. By performing this step, the liquid crystal compound in the composition layer achieves a predetermined orientation. Furthermore, as described later... Figure 8 As shown, for example, by implementing step 2B, the liquid crystal compound is aligned in parallel in the composition.

[0416] The optimal conditions for heat treatment are selected based on the liquid crystal compound used.

[0417] Among these, the heating temperatures are mostly between 25 and 250°C, even more so between 40 and 150°C, and even more so between 50 and 130°C.

[0418] The heating time is typically 0.1 to 60 minutes, with 0.2 to 5 minutes being more common.

[0419] <Process 3B>

[0420] Step 3B is as follows: After step 2B, the composition layer is subjected to an oxygen concentration of 1% by volume or higher at 300 mJ / cm². 2 The light irradiation is then performed for no more than 50 seconds. The mechanism of this process will now be described using the accompanying drawings. Furthermore, an example will be provided below where the composition layer contains a compound that becomes hydrophilic through light irradiation. Figure 8 In this composition, the liquid crystal compound (LC) is oriented in parallel within the composite layer.

[0421] like Figure 8 As shown, in process 3B, under conditions where the oxygen concentration is 1% by volume or higher, the direction from the side of the substrate 10 opposite to the side of the composition layer 222 is ( Figure 8 The direction of the hollow arrow in the image is used for illumination. Additionally, in... Figure 8 In this process, light irradiation is performed from the substrate 10 side, but it can also be performed from the composition layer 222 side.

[0422] At this point, if we compare the lower region 222A on the substrate 10 side of the composition layer 222 with the upper region 222B on the opposite side of the substrate 10 side, the surface of the upper region 222B is on the air side, therefore the oxygen concentration in the upper region 222B is high, and the oxygen concentration in the lower region 222A is low. Therefore, if the composition layer 222 is irradiated with light, the liquid crystal compound readily polymerizes in the lower region 222A, and the orientation state of the liquid crystal compound is fixed. In addition, a specific photosensitive compound is also present in the lower region 222A, and this specific photosensitive compound also becomes hydrophilic upon photosensitization. However, since the orientation state of the liquid crystal compound is fixed in the lower region 222A, even if the heat treatment step 4B, which is described later, is performed on the light-irradiated composition layer, no change in the orientation state of the liquid crystal compound will occur.

[0423] Furthermore, due to the high oxygen concentration in the upper region 222B, the polymerization of the liquid crystal compound is hindered by oxygen even under light irradiation, making polymerization difficult. Moreover, a specific photosensitive compound is also present in the upper region 222B, and this photosensitive compound becomes hydrophilic upon light exposure. Therefore, if the subsequent step 4B is performed, the orientation state of the liquid crystal compound changes due to the altered polarity.

[0424] 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. Furthermore, 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, resulting in a state where the polarity changes depending on the specific photosensitive compound.

[0425] 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.

[0426] <Process 4B>

[0427] 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 regions where the polarity changes due to specific photosensitive compounds in the composition layer that have been light-irradiated. 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.

[0428] The mechanism of this process will be described below using the accompanying drawings.

[0429] As mentioned above, if for Figure 8In step 3B of the composition layer 222 shown, the orientation state of the liquid crystal compound is fixed in the lower region 222A, while polymerization of the liquid crystal compound is difficult to occur in the upper region 222B, and the orientation state of the liquid crystal compound is not fixed. Furthermore, a specific photosensitive compound in the upper region 222B becomes hydrophilic upon light exposure. If this polarity changes, the orientation direction of the liquid crystal compound in the upper region 222B is affected compared to the state before light irradiation. This will be explained in more detail. Additionally, as described above, the following will illustrate an example where the composition layer contains a specific photosensitive compound that becomes hydrophilic upon light irradiation.

[0430] In cases where the composition layer contains a specific photosensitive compound that becomes hydrophilic upon light irradiation, such as Figure 9 As shown, if step 4B is performed, the liquid crystal compound is vertically oriented in the upper region 222B. In particular, when a specific photosensitive compound is present near the surface of the composition layer, the liquid crystal compound is more likely to be vertically oriented.

[0431] On the other hand, as described above, in the lower region 222A of the composition layer 222, the liquid crystal compound is polymerized during step 3B and the orientation state of the liquid crystal compound is fixed, so the reorientation of the liquid crystal compound is not performed.

[0432] As described above, by performing step 4B, a region containing a liquid crystal compound whose orientation is tilted or perpendicular to the layer surface can be formed.

[0433] Furthermore, as mentioned above, in the above Figure 9 The text describes the vertical orientation of liquid crystal compounds, but it is not limited to this method. For example, the liquid crystal compounds can also be oriented at an angle.

[0434] The heat treatment is carried out at a higher temperature than that under light irradiation.

[0435] The temperature difference between the heat treatment and the light irradiation temperature is preferably 5°C or more, more preferably 10 to 110°C, and even more preferably 20 to 110°C.

[0436] The preferred temperature for heat treatment is higher than the temperature during light irradiation and is a temperature that orients the unfixed liquid crystal compounds in the composition layer. More specifically, 40–250°C is more common, 50–150°C is even more common, temperatures exceeding 50°C but below 150°C are even more common, and temperatures of 60–130°C are particularly common.

[0437] The heating time is typically between 0.01 and 60 minutes, with 0.03 to 5 minutes being more common.

[0438] <Process 5B>

[0439] Step 5B is as follows: After step 4B, the composition layer is cured to form an optically anisotropic layer having regions with different orientation states of multiple liquid crystal compounds along the thickness direction. By performing this step, the orientation state of the liquid crystal compounds in the composition layer is fixed, resulting in the formation of a predetermined optically anisotropic layer. Furthermore, by performing this step, an optically anisotropic layer can be formed having regions along the thickness direction where the orientation directions of multiple liquid crystal compounds have different tilt angles relative to the surface of the optically anisotropic layer. In particular, by performing this step, an optically anisotropic layer can be formed having regions along the thickness direction where the orientation states of vertically oriented or tilted liquid crystal compounds are fixed, and regions where the orientation states of parallel-oriented liquid crystal compounds are fixed.

[0440] As a method for curing treatment in step 5B, the method for curing treatment in step 5A can be cited as an example.

[0441] There is no particular limitation on the thickness of the optical anisotropic layer that satisfies requirement 2, but it 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.

[0442] <<Requirement 3>>

[0443] The optical anisotropic layer that satisfies requirement 3 has a region along the thickness direction that fixes the orientation state of the liquid crystal compound and a region that fixes the state of the liquid crystal compound displaying an isotropic phase.

[0444] exist Figure 10 The diagram shows one embodiment of an optical anisotropy layer that satisfies requirement 3.

[0445] Figure 10 The optically anisotropic layer 320 shown is an optically anisotropic layer formed by fixing the orientation state of the liquid crystal compound, and has a first region 320A and a second region 320B along the thickness direction. The first region 320A is a region formed by fixing the orientation state of the parallel-oriented liquid crystal compound, and the second region 320B is a region formed by fixing the state in which the liquid crystal compound displays an isotropic phase.

[0446] In the above Figure 10 In this paper, an optical anisotropic layer having a region along the thickness direction in which the orientation state of the parallel-oriented liquid crystal compound is fixed and a region in which the state of the liquid crystal compound displaying an isotropic phase is fixed is described. However, this method is not limited as long as it includes a region in which the state of the liquid crystal compound displaying an isotropic phase is fixed.

[0447] For example, when the liquid crystal compound is rod-shaped, its orientation states can include nematic orientation (forming a nematic phase), smectic orientation (forming a smectic phase), cholesterol orientation (forming a cholesterol phase), and mixed orientation. When the liquid crystal compound is disc-shaped, its orientation states can include nematic orientation, columnar orientation (forming a columnar phase), and cholesterol orientation.

[0448] More specifically, an optically anisotropic layer can be formed having a region along the thickness direction in which the orientation state of a vertically oriented liquid crystal compound is fixed and a region in which the liquid crystal compound displays an isotropic phase. Furthermore, an optically anisotropic layer can also be formed using a liquid crystal compound and having a region along the thickness direction in which a cholesterol-type liquid crystal phase is fixed and a region in which the liquid crystal compound displays an isotropic phase.

[0449] There are no particular restrictions on the optical properties of the optical anisotropy layer that meets requirement 3, but it is preferred to function as a λ / 4 plate.

[0450] A λ / 4 plate is a plate that has the function of converting linearly polarized light of a specific wavelength into circularly polarized light (or converting circularly polarized light into linearly polarized light), and refers to a plate (optical anisotropic layer) whose in-plane retardation Re(λ) at a specific wavelength λnm satisfies Re(λ)=λ / 4.

[0451] This formula can be implemented at any wavelength in the visible light region (e.g., 550 nm), but preferably the in-plane delay Re(550) at a wavelength of 550 nm satisfies the relationship 110 nm ≤ Re(550) ≤ 180 nm.

[0452] There are no particular limitations on the manufacturing method of the optical anisotropy layer that satisfies requirement 3, but a manufacturing method including the following steps 1C to 5C is preferred.

[0453] Step 1C: The step of forming a composition layer, said composition layer comprising a liquid crystal compound having polymerizable groups and a leveling agent.

[0454] Step 2C: A step of heat-treating the composition layer to orient the liquid crystal compounds in the composition layer.

[0455] Step 3C: After step 2C, under conditions where the oxygen concentration is 1% by volume or higher, the composite layer is subjected to an oxygen concentration of 300 mJ / cm. 2 The following process involves light irradiation for less than 50 seconds.

[0456] Step 4C: After step 3C, a heat treatment is performed on the composition layer at a temperature higher than that during light irradiation, where the liquid crystal compound becomes an isotropic phase.

[0457] Step 5C: After step 4C, the composition layer is cured to form an optically anisotropic layer having multiple regions with different orientation states of liquid crystal compounds along the thickness direction.

[0458] The steps of each of the above processes are described in detail below.

[0459] <Process 1C>

[0460] Step 1C is the step of forming a composition layer, which comprises a liquid crystal compound having polymerizable groups and a leveling agent. By performing this step, a composition layer subjected to the light irradiation treatment described later can be formed.

[0461] The definitions and contents of the liquid crystal compounds and leveling agents contained in the composition layer are as described in step 1A.

[0462] Furthermore, as described in step 1A above, the composition layer may contain other components besides the liquid crystal compound.

[0463] In step 1A, a composition layer containing the above-described components is formed, but the steps are not particularly limited. For example, examples include coating a composition containing the above-described liquid crystal compound having polymerizable groups and a leveling agent onto a substrate and performing a drying process as needed (hereinafter, also simply referred to as the "coating method"), and another method of forming a composition layer and transferring it onto a substrate. From the viewpoint of productivity, the coating method is preferred.

[0464] The coating method is described in detail below.

[0465] The composition used in the coating method comprises the liquid crystal compound having polymerizable groups as described above, and other components used as needed (e.g., polymerization initiators, polymerizable monomers, surfactants, and polymers).

[0466] The content of each component in the composition is preferably adjusted to the content of each component in the above-mentioned composition layer.

[0467] There are no particular restrictions on the coating method. Examples include wire rod coating, extrusion coating, direct gravure coating, reverse gravure coating, and die coating.

[0468] Additionally, if necessary, after applying the composition, a drying process can be performed on the coating film applied to the substrate. By performing the drying process, the solvent can be removed from the coating film.

[0469] There is no particular limitation on the thickness of the coating, but it is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, and even more preferably 0.5 to 10 μm.

[0470] <Process 2C>

[0471] Step 2C involves heat-treating the composition layer to orient the liquid crystal compound within it. By performing this step, the liquid crystal compound in the composition layer achieves a predetermined orientation. Furthermore, as described later... Figure 11 As shown, for example, by performing step 2C, the liquid crystal compound is aligned in parallel in the composition.

[0472] The optimal conditions for heat treatment are selected based on the liquid crystal compound used.

[0473] Among these, the heating temperatures are mostly between 25 and 250°C, even more so between 40 and 150°C, and even more so between 50 and 130°C.

[0474] The heating time is typically 0.1 to 60 minutes, with 0.2 to 5 minutes being more common.

[0475] <Process 3C>

[0476] Step 3C is as follows: After step 2C, the composition layer is subjected to an oxygen concentration of 1% by volume or higher at 300 mJ / cm. 2 The following involves light exposure for no more than 50 seconds. The mechanism of this process will now be described using the accompanying drawings. Figure 11 In this composition, the liquid crystal compound (LC) is oriented in parallel within the composite layer.

[0477] like Figure 11 As shown, in process 3C, under conditions where the oxygen concentration is 1% by volume or higher, the direction from the side of the substrate 10 opposite to the side of the composition layer 322 is ( Figure 11 The direction of the hollow arrow in the image is used for illumination. Additionally, in... Figure 11 In this process, light irradiation is performed from the substrate 10 side, but it can also be performed from the composition layer 322 side.

[0478] At this point, if we compare the lower region 322A on the substrate 10 side of the composition layer 322 with the upper region 322B on the opposite side of the substrate 10 side, the surface of the upper region 322B is on the air side. Therefore, the oxygen concentration in the upper region 322B is high, while the oxygen concentration in the lower region 322A is low. Therefore, if the composition layer 322 is irradiated with light, the liquid crystal compound readily polymerizes in the lower region 322A, and the orientation state of the liquid crystal compound is fixed. Therefore, even if the heat treatment step 4C, which is described later, is performed on the light-irradiated composition layer, no change in the orientation state of the liquid crystal compound will occur.

[0479] Furthermore, due to the high oxygen concentration in the upper region 322B, the polymerization of the liquid crystal compound is hindered by oxygen even when exposed to light, making polymerization difficult. Therefore, if step 4C is performed later, the orientation state of the liquid crystal compound changes.

[0480] That is, by performing step 3C, 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 alignment state of the liquid crystal compound changes by step 4D described later.

[0481] The various conditions for light irradiation in process 3C (oxygen concentration, irradiation time, irradiation amount, etc.) are the same as those for light irradiation in process 3A above.

[0482] <Process 4C>

[0483] Step 4C is as follows: After step 3C, the composition layer is subjected to a heat treatment at a temperature higher than that during light irradiation, at which the liquid crystal compound becomes an isotropic phase. By performing this step, in the upper region where the orientation state of the liquid crystal compound in the composition layer is not fixed, the liquid crystal compound displays an isotropic phase.

[0484] The mechanism of this process will be described below using the accompanying drawings.

[0485] As mentioned above, if for Figure 11 If the composition layer 322 shown is implemented in step 3C, the orientation state of the liquid crystal compound is fixed in the lower region 322A, while it is difficult to polymerize the liquid crystal compound in the upper region 322B, and the orientation state of the liquid crystal compound is not fixed.

[0486] Therefore, if process 4C is implemented, then as follows Figure 12 As shown, no polymerization of the liquid crystal compound occurs in the upper region 322B, so the orientation state of the liquid crystal compound is destroyed and it becomes an isotropic phase.

[0487] On the other hand, as described above, in the lower region 322A of the composition layer 322, the liquid crystal compound is polymerized during process 3C and the orientation state of the liquid crystal compound is fixed, so the reorientation of the liquid crystal compound is not performed.

[0488] As described above, by performing step 4C, an optically anisotropic layer can be formed having a region along the thickness direction in which the orientation state (e.g., parallel orientation state) of the liquid crystal compound is fixed and a region in which the unoriented state (isotropic phase of the liquid crystal compound) is fixed.

[0489] The heat treatment is carried out at a temperature higher than that during light irradiation, and at a temperature above which the liquid crystal compound becomes an isotropic phase.

[0490] The temperature difference between the heat treatment and the light irradiation temperature is preferably 5°C or more, more preferably 10 to 110°C, and even more preferably 20 to 110°C.

[0491] The preferred temperature for heat treatment is higher than the temperature during light irradiation and is such that the unfixed liquid crystal compound in the composition layer is an isotropic phase. More specifically, 40–250°C is more common, 50–150°C is even more common, and temperatures exceeding 50°C but below 150°C are even more common, with 60–130°C being particularly prevalent.

[0492] The heating time is typically between 0.01 and 60 minutes, with 0.03 to 5 minutes being more common.

[0493] <Process 5C>

[0494] Step 5C is as follows: After step 4C, the composition layer is cured to form an optically anisotropic layer having multiple regions with different orientation states of liquid crystal compounds along the thickness direction. By performing this step, the orientation state of the liquid crystal compounds in the composition layer is fixed, and as a result, a specified optically anisotropic layer can be formed.

[0495] As a method for curing treatment in process 5C, the method for curing treatment in process 5A can be cited as an example.

[0496] There is no particular limitation on the thickness of the optical anisotropic layer that satisfies requirement 3, but it 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.

[0497] <<Applications>>

[0498] Optical anisotropic layers can be combined with various components.

[0499] For example, the aforementioned optical anisotropic layer can be combined with other optical anisotropic layers. That is, such as... Figure 13 As shown, a laminate 24 comprising a substrate 10, the aforementioned optical anisotropic layer 12, and other optical anisotropic layers 22 can be fabricated. Furthermore, Figure 13 The laminate 24 described herein includes a substrate 10, but the laminate may also exclude the substrate.

[0500] Other optical anisotropic layers are not particularly limited, for example, A-plates (positive A-plate and negative A-plate) and C-plates (positive C-plate and negative C-plate). Among them, C-plate is preferred from the viewpoint of easy applicability to various applications described later (e.g., circular polarizers).

[0501] There is no particular limitation on the range of the absolute value of the thickness direction delay of the C-plate at a wavelength of 550 nm, but it is preferably 5 to 300 nm, and more preferably 10 to 200 nm.

[0502] In addition, in this specification, the A-board and C-board are defined as follows.

[0503] There are two types of A-plates: positive A-plates and negative A-plates. When the refractive index along the slow axis (the direction with the highest refractive index in the plane) is set as nx, the refractive index along the direction orthogonal to the slow axis in the plane is set as ny, and the refractive index along the thickness direction is set as nz, the positive A-plate satisfies equation (A1), and the negative A-plate satisfies equation (A2). Furthermore, Rth represents a positive value for the positive A-plate and a negative value for the negative A-plate.

[0504] Equation (A1)nx>ny≈nz

[0505] Equation (A2) ny<nx≈nz

[0506] Furthermore, the “≈” above includes not only cases where the two are exactly the same, but also cases where they are practically the same. “Practically the same” means, for example, that cases where (ny-nz)×d (where d is the film thickness) is -10 to 10 nm, preferably -5 to 5 nm, are also included in “ny≈nz”, and cases where (nx-nz)×d is -10 to 10 nm, preferably -5 to 5 nm, are also included in “nx≈nz”.

[0507] There are two types of C-plates: positive C-plates and negative C-plates. Positive C-plates satisfy the relationship in equation (C1), while negative C-plates satisfy the relationship in equation (C2). Furthermore, Rth represents a negative value for positive C-plates and a positive value for negative C-plates.

[0508] Equation (C1) nz>nx≈ny

[0509] Equation (C2) nz<nx≈ny

[0510] Furthermore, the “≈” above includes not only cases where the two are exactly the same, but also cases where they are practically the same. “Practically the same” means that, for example, the case where (nx-ny)×d (where d is the film thickness) is 0 to 10 nm, preferably 0 to 5 nm, is also included in “nx≈ny”.

[0511] There are no particular limitations on the manufacturing method of the above-described laminate, and known methods can be cited. For example, a method can be cited that involves laminating an optically anisotropic layer obtained by the manufacturing method of the present invention with other optically anisotropic layers (e.g., a C-plate) to obtain a laminate. As a lamination method, other separately manufactured optically anisotropic layers can be bonded to the optically anisotropic layer obtained by the manufacturing method of the present invention, or other optically anisotropic layers can be formed by coating the optically anisotropic layer obtained by the manufacturing method of the present invention with a composition for forming other optically anisotropic layers.

[0512] Furthermore, the optical anisotropic layer obtained using the manufacturing method of the present invention can be combined with a polarizer. That is, as... Figure 14 As shown, a polarizer-equipped optical anisotropy layer 28 can be fabricated, including a substrate 10, the aforementioned optical anisotropy layer 12, and a polarizer 26. Figure 14 In this case, a polarizer 26 is disposed on the substrate 10, but it is not limited to this method. A polarizer 26 may also be disposed on the optical anisotropic layer 12.

[0513] and, Figure 14 The optical anisotropy layer 28 with polarizer described herein includes a substrate 10, but the optical anisotropy layer with polarizer may not include a substrate.

[0514] A polarizer is any component that has the function of converting natural light into specific linearly polarized light; for example, an absorption polarizer can be cited.

[0515] There are no particular restrictions on the type of polarizer; commonly used polarizers can be used, such as iodine-based polarizers, dye-based polarizers using dichroic dyes, and polyene-based polarizers. Iodine-based and dye-based polarizers are typically made by adsorbing iodine or dichroic dyes onto polyvinyl alcohol and then extending the polarizer.

[0516] In addition, protective films can be configured on one or both sides of the polarizer.

[0517] There are no particular limitations on the manufacturing method of the aforementioned optical anisotropic layer with polarizer, and known methods can be cited. For example, a method can be cited in which an optical anisotropic layer with polarizer is obtained by stacking the optical anisotropic layer obtained by the manufacturing method of the present invention with a polarizer.

[0518] Furthermore, while the method of stacking an optical anisotropic layer and a polarizer has been described above, in this invention, the stacked body can also be stacked with a polarizer to manufacture a stacked body with a polarizer.

[0519] Optical anisotropic layers can be used for a variety of applications. For example, optical anisotropic layers are preferably used for circular polarizers, and the aforementioned optical anisotropic layers with polarizers can also be used as circular polarizers.

[0520] The circular polarizer with the above structure is preferably used for anti-reflective applications in image display devices such as liquid crystal display (LCD), plasma display panel (PDP), electroluminescent display (ELD) and cathode ray tube display (CRT), and can improve the contrast ratio of the displayed light.

[0521] For example, the circular polarizer of the present invention can be used on the light extraction surface side of an organic EL display device. In this case, external light becomes linearly polarized light after passing through the polarizing film, and then becomes circularly polarized light after passing through the optical anisotropy layer. When the circularly polarized light is reflected by the metal electrode, its state is reversed, and when it passes through the optical anisotropy layer again, it becomes linearly polarized light tilted 90° from its incident angle, reaches the polarizing film, and is absorbed. As a result, the influence of external light can be suppressed.

[0522] The aforementioned optical anisotropic layer with polarizer or the laminate with polarizer is preferably suitable for organic EL display devices. That is, the optical anisotropic layer with polarizer or the laminate with polarizer is preferably disposed on the organic EL panel of the organic EL display device and is suitable for anti-reflective applications.

[0523] 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.

[0524] 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.

[0525] 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.

[0526] 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 7 As shown, the optical anisotropy layer has a region for fixing the orientation state of the parallel-aligned (horizontal-aligned) liquid crystal compound and a region for fixing the orientation state of the vertically aligned (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 parallel-aligned (horizontal-aligned) 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 parallel-aligned (horizontal-aligned) liquid crystal compound and the absorption axis of the polarizer is 0–5° or 85–95°.

[0527] Among them, the "in-plane slow axis" of the region formed by fixing the orientation state of the parallel-oriented (horizontal-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 parallel-oriented (horizontal-oriented) liquid crystal compound, and the "absorption axis" of the polarizer indicates the direction with the highest absorbance.

[0528] Furthermore, when the aforementioned optical anisotropy layer with a polarizer is used as an optical compensation plate for an IPS or FFS mode liquid crystal display device, it is preferable to arrange the polarizer, the region where the orientation state of the vertically aligned liquid crystal compound is fixed, the region where the orientation state of the parallel (horizontal) aligned liquid crystal compound is fixed, and the liquid crystal cell in that order, or the polarizer, the region where the orientation state of the parallel (horizontal) aligned liquid crystal compound is fixed, the region where the orientation state of the vertically aligned liquid crystal compound is fixed, and the liquid crystal cell in that order.

[0529] Example

[0530] The following examples and comparative examples further illustrate the features of the present invention. The materials, amounts, proportions, processing contents, and processing steps shown in the following examples can be appropriately modified without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limited by the specific examples shown below.

[0531] <Example 1>

[0532] (Fabrication of cellulose acylate membrane (substrate))

[0533] The following composition was added to a mixing vessel and stirred, then heated at 90°C for 10 minutes. The resulting composition was then filtered through filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm to prepare the doped solution. The solids concentration of the doped solution was 23.5% by mass, the amount of plasticizer added was in the ratio to cellulose acylate, and the solvent for the doped solution was dichloromethane / methanol / butanol = 81 / 18 / 1 (mass ratio).

[0534]

[0535] [Chemical Formula 8]

[0536]

[0537] [Chemical Formula 9]

[0538]

[0539] The dopant solution prepared in the above manner was cast using a roller film casting machine. After the dopant solution was cast from the mold and brought into contact with a metal support cooled to 0°C, the resulting sheet (film) was peeled off. The roller was made of SUS steel.

[0540] After the film obtained by casting is peeled from the rollers, it is dried for 20 minutes at 30-40°C using a tenter frame that clamps both ends of the film and conveys it. Subsequently, the film is post-dried by zone heating while being conveyed by rollers. The resulting film is then knurled and wound up.

[0541] The obtained cellulose acylated membrane has a thickness of 40 μm, an in-plane retardation Re(550) of 1 nm at a wavelength of 550 nm, and a thickness retardation Rth(550) of 26 nm.

[0542] (Alkali saponification treatment)

[0543] After passing the cellulose acylated membrane through a dielectric heating roller at 60°C to raise the membrane surface temperature to 40°C, an alkaline solution of the composition shown below is applied at a coating rate of 14 ml / m using a bar coater. 2 The coating was applied to the membrane strip and conveyed under a steam-type far-infrared heater manufactured by Noritake Co., Limited, heated to 110°C, for 10 seconds. Then, 3 ml / m² of pure water was similarly coated using a bar coater. 2 Next, after repeating the water washing based on a jet coating machine and the dehydration based on an air knife three times, the product is conveyed to a drying zone at 70°C for 10 seconds to dry, thereby producing an alkali-saponified cellulose acylate film.

[0544]

[0545] (Formation of the orientation film)

[0546] Using a #14 wire rod, the following oriented film coating solution was continuously coated onto the alkali-saponified surface of the cellulose acylate membrane. It was dried with warm air at 60°C for 60 seconds, and then further dried with warm air at 100°C for 120 seconds.

[0547]

[0548] (Modified polyvinyl alcohol)

[0549] [Chemical Formula 10]

[0550]

[0551] (Formation of an anisotropic optical layer)

[0552] The oriented film produced in the above manner was continuously subjected to friction treatment. At this time, the length direction of the elongated film is parallel to the conveying direction, and the angle formed between the length direction of the film (conveying direction) and the rotation axis of the friction roller is set to 45°. Setting the length direction of the film (conveying direction) to 90°, and viewing from the film side, if clockwise rotation is taken as a reference (0°) to represent a positive value, then the rotation axis of the friction roller is 135°. In other words, the position of the rotation axis of the friction roller is a position rotated 45° counterclockwise from the length direction of the film.

[0553] Using the cellulose acylated film with an orientation film that has undergone the above-mentioned friction treatment as a substrate, an optical anisotropic layer forming composition (1) containing a rod-shaped liquid crystal compound with the following composition is coated using a die coater, thereby forming a composition layer (corresponding to step 1B).

[0554] Next, the obtained composition layer was heated at 120°C for 80 seconds (corresponding to step 2B). Through this heating, the rod-shaped liquid crystal compound of the composition layer was oriented in a predetermined direction.

[0555] Subsequently, in oxygen-containing air (oxygen concentration: approximately 20% by volume), at 40°C, the composite layer was irradiated with ultraviolet light for 5 seconds using a 365nm LED lamp (manufactured by Acroedge Co., Ltd.) (irradiation dose: 30mJ / cm). 2 (Corresponds to process 3B).

[0556] Next, the obtained composition layer was heated at 90°C for 10 seconds (corresponding to step 4B).

[0557] Afterwards, nitrogen purging was performed to bring the oxygen concentration to 100 ppm by volume, and ultraviolet light was applied at 55°C using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) (irradiation dose: 500 mJ / cm²). 2 An optical anisotropy layer (corresponding to step 5B) is formed on the composition layer, thereby fixing the orientation state of the liquid crystal compound. An optical film (F-1) is fabricated in the manner described above.

[0558]

[0559]

[0560] Rod-shaped liquid crystal compound (A) (hereinafter, a mixture of compounds) [Chemical Formula 11]

[0561]

[0562] Rod-shaped liquid crystal compounds (D)

[0563] [Chemical Formula 12]

[0564]

[0565] Rod-shaped liquid crystal compounds (E)

[0566] [Chemical Formula 13]

[0567]

[0568] Polymer (A) (where the values ​​listed in each repeating unit represent the content (mass%) of each repeating unit relative to all repeating units. Weight-average molecular weight: 15000)

[0569] [Chemical Formula 14]

[0570]

[0571] Polymer (B) (where the values ​​recorded in each repeating unit represent the content (mass%) of each repeating unit relative to all repeating units.)

[0572] [Chemical Formula 15]

[0573]

[0574] Photosensitive compound (A)

[0575] [Chemical Formula 16]

[0576]

[0577] Ionic compound (A)

[0578] [Chemical Formula 17]

[0579]

[0580] Furthermore, the photosensitive compound (A) in the composition (1) for forming an optical anisotropic layer is exposed to irradiation (30 mJ / cm²). 2 When exposed to 365nm light, it produces a decomposition product (A) with a hydrophilic carboxyl group.

[0581] Decomposition products (A)

[0582] [Chemical Formula 18]

[0583]

[0584] The optical film (F-1) fabricated in the above manner was cut parallel to 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 is 4.3 μm. It is parallel oriented in a region (region 1) with a thickness of 3.0 μm on the substrate side of the optical anisotropic layer, and the liquid crystal compound is vertically oriented in a region (region 2) with a thickness of 1.3 μm on the air side of the optical anisotropic layer (the side opposite to the substrate).

[0585] Furthermore, the optical properties of the optical film (F-1) were determined using Axometrics' Axoscan and its Multi-Layer Analysis software. The in-plane retardation (Δn1d1) at 550 nm in region 1 is 140 nm, and the angle of the slow axis relative to the length direction of the film is -45°. In region 2, the in-plane retardation (Δn2d2) at 550 nm is 0 nm, and the thickness-direction retardation at 550 nm is -60 nm.

[0586] In addition, the angle of the in-plane slow axis is set to 0° with the length direction of the film as the reference. When observing the substrate from the surface side of the optical anisotropic layer, clockwise (right turn) is represented as negative and counterclockwise (left turn) is represented as positive.

[0587] <Comparative Example 1>

[0588] Using the cellulose acylated film with an orientation film that has undergone the above-mentioned friction treatment as a substrate, an optical anisotropic layer forming composition (C1-1) containing a rod-shaped liquid crystal compound with the following composition is coated using a die coater, thereby forming a composition layer.

[0589] Next, the obtained composition layer was heated at 120°C for 80 seconds. Through this heating, the rod-shaped liquid crystal compound in the composition layer was oriented in a predetermined direction.

[0590] Afterwards, nitrogen purging was performed to bring the oxygen concentration to 100 ppm by volume, and ultraviolet light was applied at 80°C using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) (irradiation dose: 200 mJ / cm²). 2 On the composite layer, an optically anisotropic layer that fixes the orientation state of the liquid crystal compound is thus formed.

[0591] Subsequently, a die coating machine is used to coat the optical anisotropic layer forming composition (C1-2) containing rod-shaped liquid crystal compound onto the optical anisotropic layer, thereby forming the composition layer.

[0592] Next, the obtained composition layer was heated at 80°C for 60 seconds. Through this heating, the rod-shaped liquid crystal compound in the composition layer was oriented in a predetermined direction.

[0593] Afterwards, nitrogen purging was performed to bring the oxygen concentration to 100 ppm by volume, and ultraviolet light was applied at 80°C using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) (irradiation dose: 500 mJ / cm²). 2 On the composite layer, an optically anisotropic layer that fixes the orientation state of the liquid crystal compound is thus formed.

[0594] An optical film (C-1) was fabricated in the manner described above.

[0595]

[0596]

[0597]

[0598] Polymer (C) (where the values ​​recorded in each repeating unit represent the content (mass%) of each repeating unit relative to all repeating units.)

[0599] [Chemical Formula 19]

[0600]

[0601] <Comparative Example 2>

[0602] The optical anisotropic layer forming composition (C-2) was used instead of the optical anisotropic layer forming composition (C1-1), and the optical film (C-2) was prepared according to the same steps as in Comparative Example 1.

[0603]

[0604]

[0605] <Comparative Example 3>

[0606] The optical anisotropic layer forming composition (C-3) was used instead of the optical anisotropic layer forming composition (C1-1), and the optical film (C-3) was prepared according to the same steps as in Comparative Example 1.

[0607]

[0608] Optical films (C-1) to (C-3) fabricated in the above manner were cut parallel to the rubbing direction, and the optical anisotropic layer was observed in cross-section using a polarizing microscope. The thickness of the optical anisotropic layer is 4.3 μm. It is parallel oriented in a region (region 1) with a thickness of 3.0 μm on the substrate side of the optical anisotropic layer, and the liquid crystal compound is vertically oriented in a region (region 2) with a thickness of 1.3 μm on the air side of the optical anisotropic layer (the side opposite to the substrate).

[0609] Furthermore, the optical properties of optical films (C-1) to (C-3) were determined using Axometrics' Axoscan and Multi-Layer Analysis software. The in-plane retardation (Δn1d1) at a wavelength of 550 nm in region 1 is 140 nm, and the in-plane slow axis is at -45° relative to the length direction of the film. In region 2, the in-plane retardation (Δn2d2) at a wavelength of 550 nm is 0 nm, and the thickness-direction retardation at a wavelength of 550 nm in region 2 is -60 nm.

[0610] In addition, the angle of the in-plane slow axis is set to 0° with the length direction of the film as the reference. When observing the substrate from the surface side of the optical anisotropic layer, clockwise (right turn) is represented as negative and counterclockwise (left turn) is represented as positive.

[0611] Furthermore, regarding the optical anisotropy layer of the embodiments and comparative examples, as described above, while utilizing Ar... + The cluster gun cut the film along the depth direction of the optical anisotropic layer, and the composition in the depth direction was analyzed using a time-of-flight secondary ion mass spectrometer (TOF-SIMS) ("SIMS5" manufactured by IONTOF).

[0612] Furthermore, in the optical anisotropy layer of the embodiment, the following can be obtained: Figure 1 The distribution shown indicates that no secondary ionic strength originating from the leveling agent exceeding 1 / 500 of the first intensity was observed at any depth in the region between the first and second positions.

[0613] In the “Secondary Ion Strength” column of the table below, the case in which no secondary ion strength of more than 1 / 500 of the first strength is observed at any depth in the region between the first and second positions is described as “A”, and the case in which it is observed is described as “B”.

[0614] Furthermore, in Example 1, secondary ion intensity originating from the leveling agent was observed at any depth in the region between the first and second positions, with an intensity less than 1 / 1000 of the first intensity. Moreover, in Comparative Examples 1 to 3, the maximum values ​​of secondary ion intensity originating from the leveling agent observed in the region between the first and second positions were 1 / 12, 1 / 120, and 1 / 400 of the first intensity, respectively.

[0615] <Stripping Evaluation>

[0616] A cross-cutting test was performed on the optical anisotropic layer of the obtained optical film. The number of grids with more than half of the area peeled off was counted after five peelings of transparent tape (registered trademark: NICHIBAN CO.,LTD. No. 405), and evaluated according to the following criteria. Furthermore, the depth of the cross-cutting was observed under a cross-section using an optical microscope. Cuts were made at a depth of more than 3 / 4 of the film thickness in the optical anisotropic layer, and the scribing was performed by applying pressure to the scribing blade without the cut reaching the substrate.

[0617] In practical use, option A is preferred.

[0618] A: The number of cells stripped is 0 or more but less than 10.

[0619] B: The number of cells stripped is more than 10 but less than 30.

[0620] C: The number of cells stripped is more than 30 and less than 50.

[0621] D: The number of tiles stripped is 50 or more.

[0622] [Table 1]

[0623] Optical film Secondary ionic strength Peelability Example 1 F-1 A A Comparative Example 1 C-1 B D Comparative Example 2 C-2 B C Comparative Example 3 C-3 B B

[0624] As shown in the table above, the desired effect can be obtained in the optical anisotropic layer of the present invention.

[0625] In contrast, in the comparative example, lattice peeling was produced, and the peeling location of the peeled lattice was observed using a cross-sectional optical microscope. The peeling occurred inside the optical anisotropic layer.

[0626] <Example 2>

[0627] (Formation of an anisotropic optical layer)

[0628] The cellulose acylated membrane prepared in Example 1 was continuously subjected to friction treatment. At this time, the length direction of the elongated membrane was parallel to the conveying direction, and the angle formed between the length direction of the membrane (conveying direction) and the rotation axis of the friction roller was 45°. Furthermore, setting the length direction of the membrane (conveying direction) to 90°, and viewing from the cellulose acylated membrane side, if the width direction of the cellulose acylated membrane is taken as a reference (0°) and the counterclockwise direction represents a positive value, then the rotation axis of the friction roller is 135°. In other words, the position of the rotation axis of the friction roller is a position rotated 45° clockwise from the length direction of the cellulose acylated membrane.

[0629] Using the cellulose acylate film that has undergone the above-mentioned friction treatment as a substrate, an optical anisotropic layer forming composition (2) containing a rod-shaped liquid crystal compound with the following composition is coated using a die coater, thereby forming a composition layer (corresponding to step 1C).

[0630] Next, the obtained composition layer was heated at 80°C for 60 seconds (corresponding to step 2C). Through this heating, the rod-shaped liquid crystal compound of the composition layer was oriented in a predetermined direction.

[0631] Subsequently, in oxygen-containing air (oxygen concentration: approximately 20% by volume), at 40°C, the composite layer was irradiated with ultraviolet light for 5 seconds using a 365nm LED lamp (manufactured by Acroedge Co., Ltd.) (irradiation dose: 50mJ / cm). 2 (Corresponds to process 3C).

[0632] Next, the obtained composition layer was heated at 120°C for 10 seconds (corresponding to step 4C). In addition, the phase transition temperature of the rod-shaped liquid crystal compound in the optical anisotropic layer formation composition (2) to the isotropic phase is 114°C.

[0633] Afterwards, nitrogen purging was performed to bring the oxygen concentration to 100 ppm by volume, and ultraviolet light was applied at 120°C using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) (irradiation dose: 500 mJ / cm²). 2 An optical anisotropy layer, which fixes the orientation state of the liquid crystal compound, is thus formed on the composition layer (corresponding to step 5C). An optical film (F-2) is fabricated in the manner described above.

[0634]

[0635] Rod-shaped liquid crystal compound (B)

[0636] [Chemical Formula 20]

[0637]

[0638] Polymerizable compounds (C)

[0639] [Chemical Formula 21]

[0640]

[0641] The optical film (F-2) fabricated in the above manner was cut parallel to 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 2.7 μm. In a region (region 1) with a thickness of 1.1 μm on the substrate side of the optical anisotropic layer, the liquid crystal compound was parallel oriented, while in a region (region 2) with a thickness of 1.6 μm on the air side (opposite to the substrate) of the optical anisotropic layer, the liquid crystal compound was in an isotropic state (isotropic phase).

[0642] Furthermore, the optical properties of the optical film (F-2) were determined using Axometrics' Axoscan and its Multi-Layer Analysis software. The in-plane retardation (Δn1d1) at a wavelength of 550 nm in region 1 was 140 nm, and the in-plane slow axis was -45°. In region 2, the in-plane retardation (Δn2d2) at a wavelength of 550 nm was 0 nm, and the retardation in the thickness direction was also 0 nm.

[0643] In addition, the angle of the in-plane slow axis is set to 0° with the length direction of the film as the reference. When observing the substrate from the surface side of the optical anisotropic layer, clockwise (right turn) is represented as negative and counterclockwise (left turn) is represented as positive.

[0644] <Comparative Example 4>

[0645] The cellulose acylated membrane prepared in Example 1 was continuously subjected to friction treatment. At this time, the length direction of the elongated membrane was parallel to the conveying direction, and the angle formed between the length direction of the membrane (conveying direction) and the rotation axis of the friction roller was 45°. Furthermore, setting the length direction of the membrane (conveying direction) to 90°, and viewing from the cellulose acylated membrane side, if the width direction of the cellulose acylated membrane is taken as a reference (0°) and the counterclockwise direction represents a positive value, then the rotation axis of the friction roller is 135°. In other words, the position of the rotation axis of the friction roller is a position rotated 45° clockwise from the length direction of the cellulose acylated membrane.

[0646] Using the cellulose acylate film that has undergone the above-mentioned friction treatment as a substrate, an optical anisotropic layer forming composition (C4-1) containing a rod-shaped liquid crystal compound with the following composition is coated using a die coater, thereby forming a composition layer.

[0647] Next, the obtained composition layer was heated at 80°C for 60 seconds. Through this heating, the rod-shaped liquid crystal compound in the composition layer was oriented in a predetermined direction.

[0648] Afterwards, nitrogen purging was performed to bring the oxygen concentration to 100 ppm by volume, and ultraviolet light was applied at 80°C using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) (irradiation dose: 200 mJ / cm²). 2 On the composite layer, an optically anisotropic layer that fixes the orientation state of the liquid crystal compound is thus formed.

[0649] Subsequently, a die coating machine is used to coat the optical anisotropic layer with a composition (C4-2) containing a rod-shaped liquid crystal compound onto the optical anisotropic layer, thereby forming a composition layer.

[0650] Next, the obtained composition layer was heated at 120°C for 60 seconds. In addition, the phase transition temperature of the rod-shaped liquid crystal compound in the optical anisotropic layer formation composition (C4-2) to the isotropic phase is 114°C.

[0651] Afterwards, nitrogen purging was performed to bring the oxygen concentration to 100 ppm by volume, and ultraviolet light was applied at 120°C using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) (irradiation dose: 500 mJ / cm²). 2An optically anisotropic layer, which fixes the orientation state of the liquid crystal compound, is thus formed on the composite layer. An optical film (C-4) was fabricated in the manner described above.

[0652] The optical film (C-4) fabricated in the above manner was cut parallel to 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 is 2.7 μm. In a region (region 1) with a thickness of 1.1 μm on the substrate side of the optical anisotropic layer, the liquid crystal compound is parallel oriented, while in a region (region 2) with a thickness of 1.6 μm on the air side (opposite to the substrate) of the optical anisotropic layer, the liquid crystal compound is in an isotropic state (isotropic phase).

[0653] Furthermore, the optical properties of the optical film (C-4) were determined using Axometrics' Axoscan and its Multi-Layer Analysis software. The in-plane retardation (Δn1d1) at a wavelength of 550 nm in region 1 was 140 nm, and the in-plane slow axis was -45°. In region 2, the in-plane retardation (Δn2d2) at a wavelength of 550 nm was 0 nm, and the retardation in the thickness direction was also 0 nm.

[0654] In addition, the angle of the in-plane slow axis is set to 0° with the length direction of the film as the reference. When observing the substrate from the surface side of the optical anisotropic layer, clockwise (right turn) is represented as negative and counterclockwise (left turn) is represented as positive.

[0655]

[0656]

[0657]

[0658] Using the obtained optical film, analysis and peelability evaluation based on the above TOF-SIMS were performed. The results are shown in Table 2.

[0659] Furthermore, in Example 2, secondary ion intensity originating from the leveling agent was observed at any depth in the region between the first and second positions, with an intensity less than 1 / 1000 of the first intensity. In Comparative Example 4, the maximum value of the secondary ion intensity originating from the leveling agent observed in the region between the first and second positions was 1 / 400 of the first intensity.

[0660] [Table 2]

[0661] Optical film Secondary ionic strength Peelability Example 2 F-2 A A Comparative Example 4 C-4 B B

[0662] As shown in the table above, the desired effect can be obtained in the optical anisotropic layer of the present invention.

[0663] In contrast, in the comparative example, lattice peeling was produced, and the peeling location of the peeled lattice was observed using a cross-sectional optical microscope. The peeling occurred inside the optical anisotropic layer.

[0664] <Example 3>

[0665] (Formation of an anisotropic optical layer)

[0666] The cellulose acylated membrane prepared in Example 1 was continuously subjected to friction treatment. At this time, the length direction of the elongated membrane was parallel to the conveying direction, and the angle formed between the length direction of the membrane (conveying direction) and the rotation axis of the friction roller was 90°.

[0667] Using the cellulose acylated film subjected to the above-mentioned friction treatment as a substrate, an optical anisotropic layer forming composition (3) comprising a rod-shaped liquid crystal compound with the following composition is coated using a die coater, thereby forming a composition layer (corresponding to step 1A). Furthermore, the absolute value of the weighted average helical torsion force of the chiral reagent in the composition layer of step 1A is 31 μm. -1 .

[0668] Next, the obtained composition layer was heated at 100°C for 80 seconds (corresponding to step 2A). Through this heating, the rod-shaped liquid crystal compound of the composition layer was oriented in a predetermined direction.

[0669] Subsequently, in oxygen-containing air at 40°C, ultraviolet light was applied to the composite layer for 10 seconds using a 365nm LED lamp (manufactured by Acroedge Co., Ltd.) (irradiation dose: 100mJ / cm). 2 (Corresponds to process 3A).

[0670] Next, the obtained composition layer was heated at 90°C for 10 seconds (corresponding to step 4A).

[0671] Afterwards, nitrogen purging was performed to bring the oxygen concentration to 100 ppm by volume, and ultraviolet light was applied at 55°C using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) (irradiation dose: 500 mJ / cm²). 2 An optical anisotropy layer, which fixes the orientation state of the liquid crystal compound, is thus formed on the composite layer (corresponding to step 5A). An optical film (F-3) is fabricated in the manner described above.

[0672]

[0673]

[0674] Right-handed tortuous chiral reagent (R1)

[0675] [Chemical Formula 22]

[0676]

[0677] The optical film (F-3) fabricated in the above manner was cut parallel to the friction direction, and the optical anisotropic layer was observed from the cross-sectional direction using SEM. The optical anisotropic layer has a thickness of 3.6 μm and has a region (region 2) with a thickness of 1.8 μm on the substrate side of the optical anisotropic layer and a region (region 1) with a thickness of 1.8 μm on the air side of the optical anisotropic layer (the side opposite to the substrate). Regions 2 and 1 are cholesterol orientations with different helical pitches.

[0678] Furthermore, the spectral reflectance characteristics of the optical film (F-3) were determined using an integral reflectometer. It was confirmed to be a dual-band cholesterol-type liquid crystal film with a reflection band centered at 450 nm originating from region 2 and a reflection band centered at 650 nm originating from region 1.

[0679] <Comparative Example 5>

[0680] The cellulose acylated membrane prepared in Example 1 was continuously subjected to friction treatment. At this time, the length direction of the elongated membrane was parallel to the conveying direction, and the angle formed between the length direction of the membrane (conveying direction) and the rotation axis of the friction roller was 90°.

[0681] Using the cellulose acylate film that has undergone the above-mentioned friction treatment as a substrate, an optical anisotropic layer forming composition (C5-1) containing a rod-shaped liquid crystal compound with the following composition is coated using a die coater, thereby forming a composition layer.

[0682] Next, the obtained composition layer was heated at 100°C for 80 seconds. Through this heating, the rod-shaped liquid crystal compound in the composition layer was oriented in a predetermined direction.

[0683] Afterwards, nitrogen purging was performed to bring the oxygen concentration to 100 ppm by volume, and ultraviolet light was applied at 80°C using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) (irradiation dose: 200 mJ / cm²). 2 On the composite layer, an optically anisotropic layer that fixes the orientation state of the liquid crystal compound is thus formed.

[0684] Subsequently, a die coating machine is used to coat the optical anisotropic layer forming composition (C5-2) containing rod-shaped liquid crystal compound onto the optical anisotropic layer, thereby forming the composition layer.

[0685] Next, the obtained composition layer was heated at 80°C for 60 seconds. Through this heating, the rod-shaped liquid crystal compound in the composition layer was oriented in a predetermined direction.

[0686] Afterwards, nitrogen purging was performed to bring the oxygen concentration to 100 ppm by volume, and ultraviolet light was applied at 55°C using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) (irradiation dose: 500 mJ / cm²). 2 An optically anisotropic layer, which fixes the orientation state of the liquid crystal compound, is thus formed on the composite layer. An optical film (C-5) was fabricated in the manner described above.

[0687] The optical film (C-5) fabricated in the above manner was cut parallel to the friction direction, and the optical anisotropic layer was observed from the cross-sectional direction using SEM. The optical anisotropic layer has a thickness of 3.6 μm and has a region (region 2) with a thickness of 1.8 μm on the substrate side of the optical anisotropic layer and a region (region 1) with a thickness of 1.8 μm on the air side of the optical anisotropic layer (the side opposite to the substrate). Regions 2 and 1 are cholesterol orientations with different helical pitches.

[0688] Furthermore, the spectral reflectance characteristics of the optical film (C-5) were determined using an integral reflectometer. It was confirmed to be a dual-band cholesterol-type liquid crystal film with a reflection band centered at 450 nm originating from region 2 and a reflection band centered at 650 nm originating from region 1.

[0689]

[0690]

[0691]

[0692] Using the obtained optical film, analysis and peelability evaluation based on the above TOF-SIMS were performed. The results are shown in Table 3.

[0693] Furthermore, in Example 3, secondary ion intensity originating from the leveling agent was observed at any depth in the region between the first and second positions, with an intensity less than 1 / 1000 of the first intensity. In Comparative Example 5, the maximum value of the secondary ion intensity originating from the leveling agent observed in the region between the first and second positions was 1 / 400 of the first intensity.

[0694] [Table 3]

[0695]

[0696]

[0697] As shown in the table above, the desired effect can be obtained in the optical anisotropic layer of the present invention.

[0698] In contrast, in the comparative example, lattice peeling was produced, and the peeling location of the peeled lattice was observed using a cross-sectional optical microscope. The peeling occurred inside the optical anisotropic layer.

[0699] <Example 4>

[0700] (Formation of an anisotropic optical layer)

[0701] The oriented film prepared in Example 1 was continuously subjected to friction treatment. At this time, the length direction of the strip-shaped film was parallel to the conveying direction, and the angle formed between the length direction of the film (conveying direction) and the rotation axis of the friction roller was 90°.

[0702] Using the cellulose acylated film with the orientation film that has undergone the above-mentioned friction treatment as a substrate, an optical anisotropic layer forming composition (4) containing a rod-shaped liquid crystal compound with the following composition is coated by a die coater, thereby forming a composition layer (corresponding to step 1B).

[0703] Next, the obtained composition layer was heated at 120°C for 80 seconds (corresponding to step 2B). Through this heating, the rod-shaped liquid crystal compound of the composition layer was oriented in a predetermined direction.

[0704] Subsequently, in oxygen-containing air (oxygen concentration: approximately 20% by volume), at 40°C, the composite layer was irradiated with ultraviolet light for 5 seconds using a 365nm LED lamp (manufactured by Acroedge Co., Ltd.) (irradiation dose: 30mJ / cm). 2 (Corresponds to process 3B).

[0705] Next, the obtained composition layer was heated at 90°C for 10 seconds (corresponding to step 4B).

[0706] Afterwards, nitrogen purging was performed to bring the oxygen concentration to 100 ppm by volume, and ultraviolet light was applied at 55°C using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) (irradiation dose: 500 mJ / cm²). 2 An optical anisotropy layer, which fixes the orientation state of the liquid crystal compound, is thus formed on the composition layer (corresponding to step 5B). An optical film (F-4) is fabricated in the manner described above.

[0707]

[0708]

[0709] Rod-shaped liquid crystal compound (F) [Chemical Formula 23]

[0710]

[0711] Rod-shaped liquid crystal compound (G) [Chemical Formula 24]

[0712]

[0713] Rod-shaped liquid crystal compound (H) [Chemical Formula 25]

[0714]

[0715] Rod-shaped liquid crystal compound (I) [Chemical Formula 26]

[0716]

[0717] The optical film (F-4) fabricated in the above manner was cut parallel to 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 is 4.3 μm. It is parallel oriented in a region (region 1) with a thickness of 2.4 μm on the substrate side of the optical anisotropy layer, and the liquid crystal compound is vertically oriented in a region (region 2) with a thickness of 1.9 μm on the air side of the optical anisotropy layer (the side opposite to the substrate).

[0718] Furthermore, the optical properties of the optical film (F-4) were determined using Axometrics' Axoscan and its Multi-Layer Analysis software. The in-plane retardation (Δn1d1) at 550 nm in region 1 is 130 nm, and the angle of the slow axis relative to the length direction of the film is 0°. In region 2, the in-plane retardation (Δn2d2) at 550 nm is 0 nm, and the thickness-direction retardation at 550 nm is -100 nm.

[0719] In addition, the angle of the in-plane slow axis is set to 0° with the length direction of the membrane as the reference.

[0720] Using the obtained optical film, analysis and peelability evaluation based on the above TOF-SIMS were performed. The results are shown in Table 4.

[0721] In addition, in Example 4, only a secondary ionic strength of less than 1 / 1000 of the first intensity originating from the leveling agent was observed at any depth in the region between the first and second positions.

[0722] [Table 4]

[0723] Optical film Secondary ionic strength Peelability Example 4 F-4 A A

[0724] As shown in the table above, the desired effect can be obtained in the optical anisotropic layer of the present invention.

[0725] Symbol Explanation

[0726] 10 - Substrate; 12, 120, 220, 320 - Optical anisotropic layers; 122, 222, 322 - Composite layers; 122A, 222A, 322A - Lower region; 122B, 222B, 322B - Upper region; 22 - Other optical anisotropic layers; 24 - Laminated structure; 26 - Polarizer; 28 - Optical anisotropic layer with polarizer.

Claims

1. An optically anisotropic layer formed using a liquid crystal compound, wherein, The optical anisotropic layer contains a leveling agent. While irradiating an ion beam from one surface of the optical anisotropic layer towards another surface, time-of-flight secondary ion mass spectrometry is used to analyze the depth-direction composition of the optical anisotropic layer to obtain the depth-direction distribution of the secondary ion intensity originating from the leveling agent. Among the secondary ion intensities originating from the leveling agent on one surface and the other surface of the optical anisotropic layer, the secondary ion intensity originating from the leveling agent with the largest intensity is designated as the first intensity, and the secondary ion intensity that is 1 / 1000 of the first intensity is designated as the second intensity. Furthermore, when the depth position representing the second intensity closest to the one surface in the distribution is designated as the first position, and the depth position representing the second intensity closest to the other surface in the distribution is designated as the second position, no secondary ion intensity originating from the leveling agent greater than 1 / 500 of the first intensity is observed at any depth in the region between the first and second positions. The optical anisotropic layer contains a compound represented by the following formula (C) as a chiral reagent. Formula (C) RLR R independently represents a group having at least one of the following motifs: cinnamyl, chalcone, azobenzene, and stilbene. L represents a divalent linker formed by removing two hydrogen atoms from the structure represented by formula (D), a divalent linker represented by formula (E), or a divalent linker represented by formula (F). in formula (E) and formula (F), represents the bonding position, The optical anisotropic layer satisfies the following requirement 1. Requirement 1: The optical anisotropic layer is an optical anisotropic layer formed by fixing a cholesterol-type liquid crystal phase, and has multiple regions with different helical pitches of the cholesterol-type liquid crystal phase along the thickness direction.

2. The optical anisotropic layer according to claim 1, wherein, The optical anisotropic layer has two regions with different helical pitches of the cholesterol-type liquid crystal phase.

3. An optically anisotropic layer formed using a liquid crystal compound having polymerizable groups and a photosensitive compound whose polarity changes upon light irradiation, wherein, The optical anisotropic layer contains a leveling agent. While irradiating an ion beam from one surface of the optical anisotropic layer towards another surface, time-of-flight secondary ion mass spectrometry is used to analyze the depth-direction composition of the optical anisotropic layer to obtain the depth-direction distribution of the secondary ion intensity originating from the leveling agent. Among the secondary ion intensities originating from the leveling agent on one surface and the other surface of the optical anisotropic layer, the secondary ion intensity originating from the leveling agent with the largest intensity is designated as the first intensity, and the secondary ion intensity that is 1 / 1000 of the first intensity is designated as the second intensity. Furthermore, when the depth position representing the second intensity closest to the one surface in the distribution is designated as the first position, and the depth position representing the second intensity closest to the other surface in the distribution is designated as the second position, no secondary ion intensity originating from the leveling agent greater than 1 / 500 of the first intensity is observed at any depth in the region between the first and second positions. The optical anisotropic layer satisfies requirement 2. Requirement 2: The optical anisotropic layer is an optical anisotropic layer formed by fixing the orientation state of the liquid crystal compound, and has multiple regions along the thickness direction where the orientation direction of the liquid crystal compound has different tilt angles relative to the surface of the optical anisotropic layer.

4. The optical anisotropic layer according to claim 3, wherein, The optical anisotropy layer has a region for fixing the orientation state of the parallel-oriented liquid crystal compound and a region for fixing the orientation state of the vertically oriented liquid crystal compound.

5. An optically anisotropic layer formed using a liquid crystal compound, wherein, The optical anisotropic layer contains a leveling agent. While irradiating an ion beam from one surface of the optical anisotropic layer towards another surface, time-of-flight secondary ion mass spectrometry is used to analyze the depth-direction composition of the optical anisotropic layer to obtain the depth-direction distribution of the secondary ion intensity originating from the leveling agent. Among the secondary ion intensities originating from the leveling agent on one surface and the other surface of the optical anisotropic layer, the secondary ion intensity originating from the leveling agent with the largest intensity is designated as the first intensity, and the secondary ion intensity that is 1 / 1000 of the first intensity is designated as the second intensity. Furthermore, when the depth position representing the second intensity closest to the one surface in the distribution is designated as the first position, and the depth position representing the second intensity closest to the other surface in the distribution is designated as the second position, no secondary ion intensity originating from the leveling agent greater than 1 / 500 of the first intensity is observed at any depth in the region between the first and second positions. The optical anisotropic layer has a region for fixing the orientation state of the parallel-aligned liquid crystal compound and a region for fixing the state in which the liquid crystal compound displays an isotropic phase, wherein the region for fixing the state in which the liquid crystal compound displays an isotropic phase is located on the outermost surface side of the optical anisotropic layer. The optical anisotropic layer satisfies requirement 3. Requirement 3: The optical anisotropic layer has a region along the thickness direction that fixes the orientation state of the liquid crystal compound and a region that fixes the state of the liquid crystal compound displaying an isotropic phase.

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