Optically anisotropic layer

Abstract

Provided is an optically anisotropic layer which has two layers in which the orientation states of liquid crystal compounds differ in the thickness direction, and which suppresses in-plane optical irregularities. This optically anisotropic layer is formed using a liquid crystal compound and has, in the thickness direction, a first layer and a second layer that is in direct contact with the first layer, and the orientation state of the liquid crystal compound in the first layer is different from the orientation state of the liquid crystal compound in the second layer. A region within a square having a maximum size that can be drawn on the surface of an optically anisotropic layer is subdivided into 64 square sub-regions having the same area, the thickness d1 of a first layer and the thickness d2 of a second layer at the center positions of the sub-regions are obtained, and X represented by formula (1) is calculated for each sub-region. When the maximum value of the calculated 64 X is Xmax and the minimum value is Xmin, the relationship of formula (2A) is satisfied. Formula (1): X = d1 / (d1 + d2), and Formula (2A): Xmax / Xmin < 1.10.

Description

[0001] This application is a divisional application of Chinese patent application No. 202180057997.2, which entered the Chinese national phase on July 27, 2021, under PCT / JP2021 / 027756. Technical Field

[0002] This invention relates to an optical anisotropic layer. Background Technology

[0003] Phase difference 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.

[0004] As an optical anisotropic layer, as described in Patent Document 1, a stacked optical anisotropic layer composed of multiple layers is disclosed.

[0005] Previous technical documents Patent documents Patent Document 1: Japanese Patent No. 5960743 Summary of the Invention

[0006] The technical problem to be solved by the invention Based on their research into the characteristics of existing layered optical anisotropic layers, the inventors discovered that in-plane optical inhomogeneities are generated. Such optical anisotropic layers with in-plane optical inhomogeneities can cause various problems when applied to various applications.

[0007] For example, when an optically anisotropic layer with in-plane optical inhomogeneity that functions as a λ / 4 plate is applied to an anti-reflective circular polarizer for an organic electroluminescent display device, color uniformity of the organic EL display device is visible. Furthermore, regarding an optically anisotropic layer formed by fixing a cholesterol-type liquid crystal phase and having in-plane optical inhomogeneity, inhomogeneity of reflected color tone is visible in-plane.

[0008] In view of the above, the objective of the present invention is to provide an optically anisotropic layer having two layers with different orientation states of liquid crystal compounds in the thickness direction, and suppressing in-plane optical inhomogeneities.

[0009] means for solving technical problems 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.

[0010] (1) An optically anisotropic layer formed using a liquid crystal compound, wherein, The optical anisotropic layer has a first layer and a second layer in direct contact with the first layer along the thickness direction. The orientation state of the liquid crystal compound in the first layer is different from that of the liquid crystal compound in the second layer. The region within the largest square that can be depicted on the surface of the optical anisotropic layer is subdivided into 64 sub-regions of the same area. The thickness d1 of the first layer and the thickness d2 of the second layer at the center of the sub-region are calculated, and X represented by Equation (1) for each sub-region is calculated. When the maximum value of the calculated 64 X is set as Xmax and the minimum value is set as Xmin, the relationship of Equation (2A) is satisfied.

[0011] Equation (1) X = d1 / (d1 + d2) Equation (2A) Xmax / Xmin < 1.10 (2) According to the optical anisotropic layer described in (1), it satisfies the relationship of equation (2B).

[0012] Equation (2B) Xmax / Xmin < 1.09 (3) The optical anisotropic layer according to (1) or (2), wherein the first layer is a layer formed by fixing the orientation state of parallel-oriented liquid crystal compounds. The second layer is formed by fixing the orientation state of a liquid crystal compound that is twisted and oriented along a spiral axis extending in the thickness direction.

[0013] (4) The optical anisotropic layer according to (1) or (2), wherein the first layer and the second layer are layers formed by fixing the orientation state of a liquid crystal compound that is twisted and oriented along a helical axis extending in the thickness direction. The twist angle of the liquid crystal compound in the first layer is different from that in the second layer.

[0014] (5) The optical anisotropic layer according to (1) or (2), wherein the first layer and the second layer are optical anisotropic layers formed by fixing a cholesterol-type liquid crystal phase. The helical pitch of the cholesterol-type liquid crystal phase in the first layer is different from that in the cholesterol-type liquid crystal phase in the second layer.

[0015] (6) The optical anisotropic layer according to (1) or (2), wherein the first layer and the second layer are optical anisotropic layers formed by fixing the orientation state of the liquid crystal compound. The tilt angle of the orientation direction of the liquid crystal compound in the first layer relative to the layer surface is different from that of the orientation direction of the liquid crystal compound in the second layer relative to the layer surface.

[0016] (7) The optical anisotropic layer according to (1) or (2), wherein the first layer is a layer formed by fixing the orientation state of parallel-oriented liquid crystal compounds. The second layer is formed by fixing the orientation state of the vertically oriented liquid crystal compound.

[0017] (8) The optical anisotropic layer according to (1) or (2), wherein the first layer is a layer formed by fixing the orientation state of the liquid crystal compound. The second layer is formed by fixing the isotropic phase state of the liquid crystal compound.

[0018] Invention Effects In this invention, an optical anisotropy layer is provided, which has two layers with different orientation states of liquid crystal compounds in the thickness direction, and suppresses in-plane optical inhomogeneity. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view showing an example of a conventional stacked optical anisotropic layer.

[0020] Figure 2 This is a cross-sectional view showing an example of the optical anisotropic layer of the present invention.

[0021] Figure 3 This is a top view of the optical anisotropic layer used to illustrate the relationship in equation (2A).

[0022] Figure 4 This is a cross-sectional view of the optical anisotropy layer within the sub-region.

[0023] Figure 5 This is a cross-sectional view showing an example of a first embodiment of the optical anisotropic layer.

[0024] Figure 6 This is a cross-sectional view of a composition layer as an example of step 3A of the manufacturing method of the first embodiment of the optical anisotropic layer.

[0025] Figure 7 This is a cross-sectional view of a composition layer as an example of step 4A of the manufacturing method of the first embodiment of the optical anisotropic layer.

[0026] Figure 8 This plots the helical torsional power (HTP) (μm) for each of chiral reagents A and B. -1 ) × concentration (mass%) and light irradiation (mJ / cm²) 2 A diagram illustrating the relationship between .

[0027] Figure 9 It plots the weighted average helical torsional force (μm) in a system using both chiral reagent A and chiral reagent B. -1 ) and light irradiance (mJ / cm 2A diagram illustrating the relationship between .

[0028] Figure 10 This is a cross-sectional view showing an example of a second embodiment of the optical anisotropic layer.

[0029] Figure 11 This is a cross-sectional view of the composition layer used to illustrate the manufacturing method of the second embodiment of the optical anisotropic layer.

[0030] Figure 12 This is a cross-sectional view of the composition layer used to illustrate the manufacturing method of the second embodiment of the optical anisotropic layer.

[0031] Figure 13 This is a cross-sectional view showing an example of a third embodiment of the optical anisotropic layer.

[0032] Figure 14 This is a cross-sectional view of a composition layer as an example of step 3B of the manufacturing method of the third embodiment of the optical anisotropic layer.

[0033] Figure 15 This is a cross-sectional view of a composition layer as an example of step 4B of the manufacturing method of the third embodiment of the optical anisotropic layer.

[0034] Figure 16 It plots the helical torsional power (HTP) (μm) of chiral reagent A. -1 ) and light irradiance (mJ / cm 2 A diagram illustrating the relationship between .

[0035] Figure 17 This is a cross-sectional view showing an example of the fourth embodiment of the optical anisotropic layer.

[0036] Figure 18 This is a cross-sectional view of a composition layer as an example of step 3C in the manufacturing method of the fourth embodiment of the optical anisotropic layer.

[0037] Figure 19 This is a cross-sectional view of a composition layer as an example of step 4C of the manufacturing method of the fourth embodiment of the optical anisotropic layer.

[0038] Figure 20 This is a cross-sectional view showing an example of the fifth embodiment of the optical anisotropic layer.

[0039] Figure 21 This is a cross-sectional view of a composition layer, which is an example of a step 3D of the manufacturing method of the fifth embodiment of the optical anisotropic layer.

[0040] Figure 22This is a cross-sectional view of a composition layer as an example of step 4D in the manufacturing method of the fifth embodiment of the optical anisotropic layer.

[0041] Figure 23 This is a cross-sectional view showing one embodiment of the laminate of the present invention.

[0042] Figure 24 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. Slow axis direction (°) Re(λ) = R0(λ) Rth(λ)=((nx+ny) / 2-nz)×d.

[0047] Additionally, R0(λ) is shown as a value calculated using AxoScan, but it represents Re(λ).

[0048] 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=589nm) 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.

[0049] Furthermore, values ​​from the Polymer Handbook (JOHN WILEY & SONS, INC) and various optical film catalogs can be used. The average refractive index values ​​of the main optical films are exemplified below: cellulose acylate (1.48), cyclic olefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).

[0050] 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.

[0051] 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.

[0052] In this specification, when the liquid crystal compound is distorted in the optical anisotropic layer, the distortion angle is preferably greater than 0° and less than 360°. Furthermore, the cholesterol-type liquid crystal phase described later is a phase having a periodic structure in which the liquid crystal compound is oriented in a helical manner, with a distortion angle of 360° or more.

[0053] As a characteristic feature of the optical anisotropic layer of the present invention, one can cite the aspect of controlling the relationship between the thickness of the first layer (described later) and the thickness of the second layer (described later) in the in-plane direction of the optical anisotropic layer.

[0054] Based on their research into the prior art, the inventors have discovered for the first time that the thickness deviation between the layers forming the optical anisotropic layer is a cause of in-plane optical inhomogeneity in the laminated optical anisotropic layer. More specifically, in Figure 1 This illustrates an example of a prior art stacked optical anisotropic layer. Figure 1In the optical anisotropic layer 100 formed by stacking the first layer 102 and the second layer 104 as described, for example, when the thickness of the first layer 102 at position X is set to d1X and the thickness of the second layer 104 is set to d2X, and the thickness of the first layer 102 at position Y is set to d1Y and the thickness of the second layer 104 is set to d2Y, d1X and d1Y, d2X and d2Y are very different from each other. As a result, the optical properties at position X are different from those at position Y, thus producing in-plane optical inhomogeneity. In addition, in the prior art, as a reason for the large thickness deviation as described above, for example, when the first layer and the second layer are formed by sequential coating, if the composition used to form the first layer does not contain a leveling agent, unevenness is easily generated due to the surface tension of the first layer, resulting in the structure described above. Furthermore, when light irradiation is applied to fix the orientation state of the liquid crystal compound, a structure as described above is easily formed when the distribution of irradiation amount within the irradiation range of the irradiated light is large. That is, if regions that are easy to cure due to high irradiation amount and regions that are difficult to cure due to low irradiation amount are generated during light irradiation, a structure as described above is easily formed.

[0055] The inventors discovered for the first time that the in-plane optical non-uniformity described above is caused by the deviation in the thickness of each layer, and thus found that the desired effect can be obtained by controlling the thickness of each layer within a specified range.

[0056] The optical anisotropic layer (layered film) of the present invention will now be described in detail.

[0057] The optical anisotropy layer of the present invention is a layer formed using a liquid crystal compound and exhibiting optical anisotropy. Furthermore, as described later, the optical anisotropy layer of the present invention may include a layer that does not exhibit optical anisotropy. That is, the optical anisotropy layer of the present invention, as described later, has a first layer and a second layer; it is permissible for at least one of the two layers to exhibit optical anisotropy, or it may be a layer that does not exhibit optical anisotropy.

[0058] The optical anisotropic layer of the present invention can be formed using a liquid crystal compound, and is preferably a layer formed by fixing a liquid crystal compound. Specific embodiments of the optical anisotropic layer can be described in the first to fifth embodiments described later, and will be detailed in the following sections.

[0059] Optical anisotropic layers can contain materials other than liquid crystal compounds.

[0060] 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.

[0061] The optical anisotropic layer has a first layer and a second layer in direct contact with the first layer along its thickness direction. More specifically, such as... Figure 2 As shown, the optical anisotropy layer 10 has a first layer 12 and a second layer 14.

[0062] The orientation state of the liquid crystal compound in the first layer differs from that in the second layer. Regarding the difference in the orientation state of the liquid crystal compound, for example, one of the first and second layers may be in an unoriented state (an isotropic phase) while the other is oriented in a manner that forms a predetermined liquid crystal phase. Furthermore, even if both the first and second layers are oriented in a manner that forms a predetermined liquid crystal phase, the orientation state will differ if the type of liquid crystal phase, orientation direction, and twist angle, etc., are different. Specifically, the first to fifth embodiments described later illustrate ways in which the orientation states of the liquid crystal compounds differ.

[0063] The optical anisotropic layer of the present invention satisfies the relationship of equation (2A) described later. Hereinafter, the relationship of equation (2A) will be described in detail with reference to the accompanying drawings.

[0064] Figure 3 This is a top view of the optical anisotropy layer 10, and it is from... Figure 2 The hollow arrow in the attached diagram shows the optical anisotropy layer 10. Figure 3 In this context, the shape of the surface of the optical anisotropy layer 10 is square. However, as will be described later, the shape of the surface of the optical anisotropy layer 10 is not limited to... Figure 3 In this way.

[0065] First, a square of the largest possible size is drawn on the surface of the optical anisotropic layer. Figure 3 As described above, the surface of the optical anisotropy layer 10 is square, thus enabling the depiction of a square that occupies the entire surface of the optical anisotropy layer 10.

[0066] Next, as Figure 3 As shown, the depicted square is subdivided into 64 sub-regions of equal area. That is, as... Figure 3 As shown, the vertical side of the depicted square ( Figure 3 The dashed lines are drawn in an eight-part manner, dividing the square into eight equal parts, and the horizontal side of the square being drawn is also divided into eight parts. Figure 3 The square is divided into eight equal parts by a dashed line extending from the left and right sides, and the square is further subdivided into 64 sub-regions of equal area.

[0067] Next, the thickness d1 of the first layer and the thickness d2 of the second layer at the center of each sub-region are calculated. If... Figure 3 Taking the top left sub-region 16 as an example, let's first... Figure 3 As shown, the center position CP within sub-region 16 is determined. The center position CP is located at the center of the square sub-region 16. More specifically, the center position is defined as the intersection of the two diagonals of the square sub-region 16.

[0068] Next, as Figure 4 As shown, the thickness d1 of the first layer and the thickness d2 of the second layer at the center position CP of subregion 16 are calculated. For example, the thickness can be calculated by cutting the optical anisotropic layer along a line passing through the center position CP and observing the exposed cross-section of the optical anisotropic layer using a polarizing microscope.

[0069] Perform the above steps for each subregion to calculate X represented by equation (1) for each subregion.

[0070] Equation (1) X = d1 / (d1 + d2) Next, when the maximum value is set to Xmax and the minimum value is set to Xmin among the 64 calculated X (each of the 64 sub-regions), as shown in Equation (2A), the Xmax / Xmin of the optical anisotropy layer of the present invention is less than 1.10.

[0071] Equation (2A) Xmax / Xmin < 1.10 Furthermore, from the viewpoint of further suppressing in-plane optical inhomogeneities (hereinafter also referred to as "the viewpoint of better performance of the present invention"), it is preferable to satisfy the relationship of formula (2B).

[0072] Equation (2B) Xmax / Xmin < 1.09 There is no particular restriction on the lower limit of Xmax / Xmin, but it is more common for it to exceed 1.00.

[0073] Additionally, when Xmax and Xmin are the same, Xmax / Xmin is set to 1.00.

[0074] There are no particular limitations on the manufacturing method of the optical anisotropy layer that satisfies the relationship of the above equation (2A), but for example, methods can be used to suppress the deviation of the amount of irradiation within the range (in-plane) of the irradiated light during illumination. As methods to suppress the deviation of the amount of irradiation, for example, methods can be used to adjust the amount of irradiation in the plane by adjusting the output of the light source, or methods can be used to adjust the amount of irradiation in the plane by placing a filter between the light source and the irradiated object in the range where the amount of irradiation is high.

[0075] From the viewpoint of achieving better results with this invention, the difference between the maximum and minimum irradiation dose within the irradiation range during light irradiation is preferably 1.0 mJ / cm². 2 The preferred value is 0.7 mJ / cm. 2 The lower bound is not specifically limited, but 0 can be cited as an example.

[0076] Furthermore, from the viewpoint of achieving better results with the present invention, the ratio of the maximum irradiation dose to the minimum irradiation dose (maximum irradiation dose / minimum irradiation dose) is preferably 1.10 or less, more preferably 1.05 or less. There is no particular limitation on the lower limit, but 1 can be cited as an example. That is, it is preferable that the irradiation dose is constant in the plane.

[0077] In addition, as mentioned above, in Figure 3 The optical anisotropic layer 10 is shown to have a square surface shape, but it is not limited to this shape. For example, the surface shape of the optical anisotropic layer 10 can be rectangular, elliptical, trapezoidal, or amorphous.

[0078] There is no particular limitation on the thickness of the optical anisotropic layer, 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.

[0079] There is no particular restriction on the ratio of the thickness of the first layer to the thickness of the second layer (thickness of the first layer / thickness of the second layer), but it is more common to find values ​​between 0.1 and 5.0, and even more common to find values ​​between 0.2 and 3.0.

[0080] As described above, the optical anisotropy layer has a first layer and a second layer with different orientation states of the liquid crystal compound. There are no particular limitations on the first layer and the second layer, but the following first to fifth embodiments are preferred.

[0081] First embodiment: The first layer is a layer formed by fixing the orientation state of a parallel-oriented liquid crystal compound, and the second layer is a layer formed by fixing the orientation state of a liquid crystal compound that is twisted along a spiral axis extending in the thickness direction.

[0082] Second embodiment: The first layer and the second layer are layers formed by fixing the orientation state of liquid crystal compounds that are twisted along a spiral axis extending in the thickness direction. The twist angle of the liquid crystal compound in the first layer is different from that of the liquid crystal compound in the second layer.

[0083] Third embodiment: The first layer and the second layer are optical anisotropic layers formed by fixing a cholesterol-type liquid crystal phase. The helical pitch of the cholesterol-type liquid crystal phase in the first layer is different from that in the second layer.

[0084] Fourth embodiment: The first layer and the second layer are optical anisotropic layers formed by fixing the orientation state of the liquid crystal compound. The tilt angle of the orientation direction of the liquid crystal compound in the first layer relative to the layer surface is different from the tilt angle of the orientation direction of the liquid crystal compound in the second layer relative to the layer surface.

[0085] Fifth embodiment: The first layer is a layer formed by fixing the orientation state of the liquid crystal compound, and the second layer is a layer formed by fixing the state of the liquid crystal compound displaying an isotropic phase.

[0086] The first to fifth embodiments described above will now be described in detail.

[0087] 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.

[0088] Furthermore, in the optically anisotropic layer, the composition in the final layer no longer needs to exhibit liquid crystal properties.

[0089] <<First Embodiment>> In the first embodiment of the optical anisotropic layer, the first layer is a layer formed by fixing the orientation state of a parallel-oriented liquid crystal compound, and the second layer is a layer formed by fixing the orientation state of a liquid crystal compound that is twisted along a spiral axis extending in the thickness direction.

[0090] exist Figure 5 An example of a first embodiment of the optical anisotropic layer is shown.

[0091] Figure 5 The optical anisotropic layer 200 shown is an optical anisotropic layer formed using a liquid crystal compound (LC), and has a first layer 200A and a second layer 200B along the thickness direction. The first layer 200A is a layer formed by fixing the orientation state of a parallel-oriented liquid crystal compound, and the second layer 200B is a layer formed by fixing the orientation state of a liquid crystal compound that is twisted along a helical axis extending along the thickness direction.

[0092] The liquid crystal compound in the second layer 200B can be twisted to the left (counterclockwise) or to the right (clockwise).

[0093] In this specification, parallel orientation refers to the state in which the molecular axes of the 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 surface of the composition layer (optical uniaxiality).

[0094] 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 composition layer forms an angle of inclination of less than 20° with the surface of the composition layer.

[0095] 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°.

[0096] When the thickness of the first layer in the first embodiment is set to d1 and the anisotropy of the refractive index of the first layer 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, the first layer preferably satisfies the following formula (1A-1).

[0097] Equation (1A-1): 100nm≤Δn1d1≤240nm Among them, it is more preferable to satisfy equation (1A-2), and even more preferable to satisfy equation (1A-3).

[0098] Equation (1A-2) 120nm≤Δn1d1≤220nm Equation (1A-3) 140nm≤Δn1d1≤200nm When the thickness of the second layer in the first embodiment is set to d2 and the anisotropy of the refractive index of the second layer measured at a wavelength of 550 nm is set to Δn2, from the viewpoint that the optical anisotropy layer can be preferably applied to a circular polarizer, the second layer preferably satisfies the following formula (2A-1).

[0099] Equation (2A-1): 100nm≤Δn2d2≤240nm Among them, it is more preferable to satisfy equation (2A-2), and even more preferable to satisfy equation (2A-3).

[0100] Equation (2A-2): 120nm≤Δn2d2≤220nm Equation (2A-3) 140nm≤Δn2d2≤200nm The absolute value of the twist angle of the liquid crystal compound in the second layer is not particularly limited, but from the viewpoint that the optical anisotropy layer can be preferably applied to a circular polarizer, it is preferably 50 to 110°, and more preferably 60 to 100°.

[0101] Furthermore, firstly, the twisted orientation of the liquid crystal compound refers to the orientation along the thickness direction of the second layer, from one surface of the second layer (…). Figure 5 From the first layer side surface to another surface ( Figure 5The twist angle refers to the angle formed by the molecular axis (or major axis in the case of rod-shaped liquid crystal compounds) of the liquid crystal compound on one surface of the second layer and the molecular axis of the liquid crystal compound on the other surface of the second layer.

[0102] The torsion angle was measured using Axometrics' Axoscan and Axometrics' device analysis software.

[0103] The first embodiment of the optical anisotropic layer preferably represents reverse wavelength dispersion.

[0104] 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).

[0105] The optical properties of the first embodiment of the optical anisotropic layer are not particularly limited, but it is preferred to function as a λ / 4 plate.

[0106] 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.

[0107] 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.

[0108] The manufacturing method of the first embodiment of the optical anisotropic layer is not particularly limited, but a manufacturing method including the following steps 1A to 5A is preferred.

[0109] 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 and a liquid crystal compound having polymerizable groups. Step 2A: A step of heat-treating the composition layer to orient the liquid crystal compounds in the composition layer. Step 3A: After step 2A, under conditions where the oxygen concentration is 1% by volume or higher, the composite layer is subjected to 300 mJ / cm 2 The following process involves light irradiation for less than 50 seconds. 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. Step 5A: After step 4A, the composite layer is cured to form an optically anisotropic layer. As described later, in the first embodiment, in order to manufacture an optically anisotropic layer with the above-described properties, the total content of chiral reagents in the composition layer (the total content of all chiral reagents) is preferably 5.0% by mass or less relative to the total mass of the liquid crystal compound.

[0110] The steps of each of the above processes are described in detail below.

[0111] <Process 1A> 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 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.

[0112] The following sections will first describe in detail the materials used in this process, and then describe the steps of the process in detail.

[0113] (Chiral reagent) 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.

[0114] 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).

[0115] Formula (A) HTP = 1 / (length of helical pitch (unit: μm) × concentration of chiral reagent relative to liquid crystal compound (mass%)) [μm -1 ] 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).

[0116] 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.

[0117] 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.

[0118] 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".

[0119] 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.

[0120] 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 refer to decomposition, addition reactions, isomerization, racemization, [2+2] photocyclization, and dimerization reactions that occur when light is irradiated onto the photoreactive site; these structural changes can be irreversible. Additionally, chiral sites include, for example, the asymmetric carbon described in Hiroyuki Nohira, General Chemical Studies, No. 22 Chemistry of Liquid Crystals, 73p: 1994.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] Chiral reagent A preferably has a structure selected from the following: a binatyl moiety, an isosorbide moiety (a moiety derived from isosorbide), and an isomannitol moiety (a moiety derived from isomannitol). Furthermore, the binatyl moiety, isosorbide moiety, and isomannitol moiety refer to the following structures, respectively.

[0126] In the binaphthalene moiety structure, the parallel solid and dashed lines represent single or double bonds. Additionally, in the structures shown below, Indicates the bonding location.

[0127] [Chemical Formula 1] 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.

[0128] As the chiral reagent A, the compound represented by formula (C) is preferred.

[0129] Formula (C) RLR R independently represents a group having at least one part selected from the group consisting of cinnamyl, chalcone, azobenzene and stilbene.

[0130] 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 naphthalene 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).

[0131] In equations (E) and (F), Indicates the bonding location.

[0132] [Chemical Formula 2] 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.

[0133] 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.

[0134] Chiral reagent B can have polymerizable groups. Examples of polymerizable groups that chiral reagent A can possess can be cited.

[0135] As chiral reagent B, known chiral reagents can be used.

[0136] 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.

[0137] 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).

[0138] 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.

[0139] In the first embodiment, 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 5.0% by mass or less relative to the total mass of the liquid crystal compound, more preferably 4.0% by mass or less, even more preferably 2.0% by mass or less, and particularly preferably 1.0% by mass or less. The lower limit is not particularly limited, but it is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.05% by mass.

[0140] 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.

[0141] (Liquid crystal compound) The composition layer of step 1A contains a liquid crystal compound having polymerizable groups.

[0142] 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 types (rod-shaped liquid crystal compounds) and disc-shaped types (disc-shaped liquid crystal compounds). Furthermore, liquid crystal compounds can be classified into low-molecular-weight types 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.

[0143] 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 can be preferred, for example.

[0144] As a disc-shaped liquid crystal compound, the disc-shaped liquid crystal compound described in Japanese Patent Application Publication No. 2007-108732, paragraphs 0020 to 0067, or Japanese Patent Application Publication No. 2010-244038, paragraphs 0013 to 0108, is preferred.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] (Other ingredients) The composition layer may contain other components besides the chiral reagents and liquid crystal compounds mentioned above.

[0149] 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.

[0150] 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.

[0151] The polymerization initiator preferably has a molar absorptivity of less than 0.1 times that of the wavelength of light irradiated in step 3A.

[0152] 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.

[0153] 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.

[0154] The composition layer may contain a photosensitizer.

[0155] There are no particular restrictions on the types of photosensitizers; any well-known photosensitizers can be cited.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] The content of polymerizable monomers in the composition layer is not particularly limited, but it is preferably 1 to 50% by mass relative to the total mass of the liquid crystal compound, more preferably 5 to 30% by mass.

[0160] The composition layer may contain a leveling agent.

[0161] 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.

[0162] Fluorinated leveling agents are leveling agents containing fluorine atoms, preferably containing fluorinated aliphatic groups.

[0163] Fluorine leveling agents preferably have repeating units represented by formula (1).

[0164] [Chemical Formula 3] In equation (1), R 1 It represents a hydrogen atom, a halogen atom, or a methyl group.

[0165] L 1This 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 ynynyl 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 groups, -(O-divalent hydrocarbon groups)). m -O- (m represents an integer greater than 1) and -O-CO-2 valence hydrocarbon groups, etc.

[0166] n represents an integer from 1 to 18, preferably an integer from 4 to 12, and more preferably an integer from 6 to 8.

[0167] X is a hydrogen atom or a fluorine atom.

[0168] 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).

[0169] [Chemical Formula 4] 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).

[0170] 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.

[0171] m represents an integer from 1 to 6, preferably an integer from 1 to 3.

[0172] Fluorinated leveling agents may have only one repeating unit represented by formula (1), or they may have two or more repeating units.

[0173] The content of the repeating unit represented by formula (1) in the fluorinated leveling agent is not particularly limited. From the viewpoint that it is easy to form 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.

[0174] When the fluorinated leveling agent has two or more repeating units represented by formula (1), the total content is preferably within the above range.

[0175] Fluorinated leveling agents may have repeating units other than those represented by formula (1).

[0176] Other repeating units may include repeating units containing hydrophilic groups (e.g., poly(oxyalkylene) groups, hydroxyl groups, etc.).

[0177] Fluorinated leveling agents can have repeating units as represented by formula (3).

[0178] [Chemical Formula 5] R 3 It represents a hydrogen atom, a halogen atom, or a methyl group.

[0179] L 2 This indicates a single bond or a divalent linker. The definition of a divalent linker is as described above.

[0180] L 3 This indicates an alkylene group. The preferred number of carbon atoms in an alkylene group is 2 to 3.

[0181] p represents an integer from 4 to 20, preferably an integer from 5 to 15.

[0182] R 4 This 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.).

[0183] Fluorinated leveling agents may have only one repeating unit represented by formula (3), or they may have two or more repeating units.

[0184] The content of the repeating unit represented by formula (3) in the fluorinated leveling agent is not particularly limited. From the viewpoint that it is easy to form 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.

[0185] When the fluorinated leveling agent has two or more repeating units represented by formula (3), its total content is preferably within the above range.

[0186] 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.

[0187] As a silicone-based leveling agent, a leveling agent containing multiple dialkylsiloxy units as repeating units is preferred.

[0188] There is no particular limitation on the content of leveling agent in the optical anisotropic layer, but it 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.

[0189] 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.

[0190] There is no particular limitation on the content of polymer in the composition layer, 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.

[0191] 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.

[0192] (Substrate) As described later, when forming the composition layer, it is preferable to form the composition layer on a substrate.

[0193] The substrate is a plate that supports the composite layer.

[0194] 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.

[0195] 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.

[0196] 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.

[0197] The preferred material for forming the substrate is a polymer with excellent optical transparency, mechanical strength, thermal stability, moisture shielding properties, and isotropy.

[0198] 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))).

[0199] 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.

[0200] The substrate may contain various additives (e.g., optical anisotropy modifiers, wavelength dispersion modifiers, microparticles, plasticizers, UV protectants, degradation inhibitors, stripping agents, etc.).

[0201] 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.

[0202] Furthermore, an adhesive layer (base coat) can be applied to the substrate.

[0203] 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%.

[0204] 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.

[0205] 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.

[0206] 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.

[0207] An alignment film can be disposed on the substrate.

[0208] Orientation 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).

[0209] 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).

[0210] The orientation film is preferably formed by friction treatment of the polymer.

[0211] 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.

[0212] 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.

[0213] As described above, the alignment film can be formed by coating a solution containing the aforementioned polymer as the alignment film forming material and any additives (e.g., crosslinking agents) onto a substrate, followed by heating and drying (to crosslink) and then rubbing.

[0214] (Steps of process 1A) In step 1A, a composition layer containing the above-described components is formed, but the steps are not particularly limited. For example, examples include a method of coating a composition containing the above-described chiral reagent and a liquid crystal compound having polymerizable groups 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. Of these, from the viewpoint of productivity, the coating method is preferred.

[0215] The coating method is described in detail below.

[0216] The composition used in the coating method includes the chiral reagent described above, a liquid crystal compound having polymerizable groups, and other components used as needed (e.g., polymerization initiators, polymerization monomers, surfactants, and polymers).

[0217] The content of each component in the composition is preferably adjusted to the content of each component in the above-mentioned composition layer.

[0218] 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.

[0219] 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.

[0220] 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.

[0221] <Process 2A> Step 2A is as follows: The composition layer is subjected to heat treatment to orient the liquid crystal compound in the composition layer. By performing this step, the liquid crystal compound in the composition layer is brought into a predetermined orientation state.

[0222] The optimal conditions for heat treatment are selected based on the liquid crystal compound used.

[0223] 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.

[0224] The heating time is typically 0.1 to 60 minutes, with 0.2 to 5 minutes being more common.

[0225] 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.

[0226] In order to form an optically anisotropic layer having a layer in which the orientation of liquid crystal compounds oriented in a twisted manner along a helical axis extending in the thickness direction is fixed, and a layer in which the orientation of liquid crystal compounds oriented in a parallel manner is fixed, the absolute value of the weighted average helical torsion force of the chiral reagent in the composition layer formed by step 1A is preferably 0.0 to 1.9 μm. -1 More preferably, it is 0.0–1.5 μm. -1 More preferably 0.0–1.0 μm -1 Especially preferred is 0.0–0.5 μm. -1 More particularly preferred is 0.0–0.02 μm. -1 The optimal value is zero.

[0227] 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).

[0228] 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) 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 .

[0229] When the absolute value of the weighted average helical torsional force of the chiral reagent in the composition layer formed by step 1A is 0, such as Figure 6 As shown, a liquid crystal compound (LC) parallel-aligned composition layer 202 can be formed on substrate 18. Furthermore, Figure 6 This is a cross-sectional view of the substrate 18 and the composition layer 202. Additionally, in Figure 6 In the composition layer 202 shown, chiral reagent A and chiral reagent B are present at the same concentration, with the helical direction of chiral reagent A being left-handed and the helical direction of chiral reagent B being right-handed. Furthermore, the absolute value of the helical torsional force of chiral reagent A is the same as the absolute value of the helical torsional force of chiral reagent B.

[0230] <Process 3A> Step 3A is as follows: After step 2A, under conditions where the oxygen concentration is 1% by volume or higher, the composite layer is subjected to 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. Furthermore, the following will focus on... Figure 6 The example shown is a representative example of a composition layer 202 in which process 3A has been performed.

[0231] like Figure 6 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 18 opposite to the side of the composition layer 202 ( Figure 6 The direction of the hollow arrow in the image is used for illumination. Additionally, in... Figure 6In this process, light irradiation is performed from the substrate 18 side, but it can also be performed from the composition layer 202 side.

[0232] At this point, if we compare the lower region 202A on the substrate 18 side of the composition layer 202 with the upper region 202B on the opposite side of the substrate 18 side, the surface of the upper region 202B is on the air side, therefore the oxygen concentration in the upper region 202B is high, and the oxygen concentration in the lower region 202A is low. Therefore, if the composition layer 202 is irradiated with light, the liquid crystal compound is easily polymerized in the lower region 202A, and the orientation state of the liquid crystal compound is fixed. In addition, chiral reagent A is also present in the lower region 202A, 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 202A, 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.

[0233] Furthermore, due to the high oxygen concentration in the upper region 202B, 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 202B, and therefore, the helical torsion force changes upon photosensitive reaction to chiral reagent A. Thus, if step 4A described later is performed, the orientation state of the liquid crystal compound changes along with the altered helical torsion force.

[0234] 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, resulting in a state where the helical torsional force varies according to the photosensitive chiral reagent A.

[0235] Step 3A is performed under conditions where the oxygen concentration is 1% by volume or more. Specifically, in the optical anisotropic layer, from the viewpoint that layers with different orientation states of the liquid crystal compound are easily formed, 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.

[0236] 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.

[0237] The light irradiation dose in process 3A is 300 mJ / cm. 2From the viewpoints of ease of forming a specified optical anisotropy layer and productivity, 250 mJ / cm is preferred. 2 Below, 200 mJ / cm is more preferred. 2 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 / cm being more ideal. 2 above.

[0238] In addition, the light irradiation in step 3A of the first embodiment is preferably carried out at 15 to 70°C (preferably 25 to 50°C).

[0239] 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.

[0240] <Process 4A> 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.

[0241] The mechanism of this process will be described below using the accompanying drawings.

[0242] As mentioned above, if for Figure 6 In the embodiment of step 3A of the composition layer 202 shown, the orientation state of the liquid crystal compound is fixed in the lower region 202A, while polymerization of the liquid crystal compound is difficult to occur in the upper region 202B, 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 202B. 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 202B changes. This will be explained in more detail.

[0243] As mentioned above, in Figure 6In the composition layer 202 shown, chiral reagent A and chiral reagent B are present at the same concentration, with the helical direction of chiral reagent A being left-handed and the helical direction of chiral reagent B being right-handed. Furthermore, the absolute value of the helical torsional force of chiral reagent A is the same as the absolute value of the helical torsional force of chiral reagent B. Therefore, the weighted average helical torsional force of the chiral reagents in the composition layer before light irradiation is 0.

[0244] The above method is shown in Figure 8 In. Figure 8 In the middle, the vertical axis represents the helical torsional force of the chiral reagent (μm). -1 The value of chiral reagent A is expressed as "(m² × concentration of chiral reagent (mass%)", and the further away from zero, the greater the helical torsional force. First, the relationship between chiral reagent A and chiral reagent B in the composition layer before light irradiation corresponds to the point when the light irradiation amount is 0, and corresponds to "the helical torsional force of chiral reagent A (μm)". -1 The absolute value of "concentration (mass%) of chiral reagent A" and "helical torsional force (μm) of chiral reagent B" are expressed as follows: -1 The absolute values ​​of "concentration (mass%) of chiral reagent A × chiral reagent B" are equal. That is, the helical torsional forces of chiral reagent A, which causes left-handed rotation, and chiral reagent B, which causes right-handed rotation, cancel each other out.

[0245] Light is irradiated in the upper region 202B of this state, such as... Figure 8 As shown, when the helical torsional force of chiral reagent A decreases according to the amount of light irradiation, such as Figure 9 As shown, the weighted average helical torsion force of the chiral reagent in the upper region 202B increases, and the right-handed helical torsion force becomes stronger. That is, regarding the helical torsion force of the helix of the torsion liquid crystal compound, the greater the irradiation dose, the greater the helical torsion force in the direction (+) of the helix twisted by the chiral reagent B.

[0246] Therefore, if the composition layer 202 after process 3A, where the weighted average helical torsional force changes, is subjected to heat treatment to promote the reorientation of the liquid crystal compound, then as... Figure 7 As shown, in the upper region 202B, the liquid crystal compound LC is twisted and oriented along a helical axis extending along the thickness direction of the composition layer 202.

[0247] On the other hand, as described above, in the lower region 202A of the composition layer 202, 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.

[0248] As described above, by performing step 4A, two regions with different orientation states of the liquid crystal compound are formed along the thickness direction of the composition layer.

[0249] In addition, in the above Figure 6 and Figure 7 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. In this case, the helical torsional force of chiral reagent A increases upon light irradiation, and the liquid crystal compound is twisted and oriented along the rotation direction of the chiral reagent A.

[0250] Furthermore, in the above Figure 6 and Figure 7 The text describes the simultaneous use of chiral reagent A and chiral reagent B, but is not limited to this method. For example, it is also possible to use two chiral reagents A. Specifically, it is also possible to use simultaneously a chiral reagent A1 that induces levorotation and a chiral reagent A2 that induces dextrorotation. Chiral reagent A1 and chiral reagent A2 can be chiral reagents that increase helical torsional force or chiral reagents that decrease helical torsional force, respectively. For example, it is possible to use simultaneously a chiral reagent that induces levorotation and whose helical torsional force increases upon light irradiation and a chiral reagent that induces dextrorotation and whose helical torsional force decreases upon light irradiation.

[0251] The heat treatment is carried out at a higher temperature than that under light irradiation.

[0252] 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.

[0253] 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, 35 to 250°C is more common, 50 to 150°C is even more common, temperatures above 50°C and below 150°C are even more common, and temperatures of 60 to 130°C are particularly common.

[0254] The heating time is typically between 0.01 and 60 minutes, with 0.03 to 5 minutes being more common.

[0255] Furthermore, there is no particular limitation on the absolute value of the weighted average helical torsion force of the chiral reagent in the composition layer after light irradiation, but the absolute value of the difference between the weighted average helical torsion force of the chiral reagent 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 .

[0256] <Process 5A> Step 5A is as follows: After step 4A, the composition layer is cured to form an optically anisotropic layer. By performing this step, the orientation state of the liquid crystal compound in the composition layer is fixed, and as a result, a specified optically anisotropic layer can be formed.

[0257] 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.

[0258] Ultraviolet radiation is achieved using light sources such as ultraviolet lamps.

[0259] 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.

[0260] 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.

[0261] 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.

[0262] 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.

[0263] In the optically anisotropic layer obtained by performing a curing process, the orientation state of the liquid crystal compound is fixed.

[0264] <<Second Implementation>> In the second embodiment of the optical anisotropic layer, the first layer and the second layer are layers formed by fixing the orientation state of liquid crystal compounds that are twisted and oriented along a helical axis extending in the thickness direction, and the twist angle of the liquid crystal compound in the first layer is different from that in the second layer.

[0265] exist Figure 10 An example of a second embodiment of the optical anisotropic layer is shown.

[0266] Figure 10The optically anisotropic layer 300 shown is an optically anisotropic layer formed using a liquid crystal compound (LC), and has a first layer 300A and a second layer 300B along the thickness direction. Both the first layer 300A and the second layer 300B are layers formed by fixing the orientation state of a liquid crystal compound that is twisted and oriented along a helical axis extending along the thickness direction. The twist angle of the liquid crystal compound in the first layer 300A is different from the twist angle of the liquid crystal compound in the second layer 300B.

[0267] The liquid crystal compounds in layer 1 (300A) and layer 2 (300B) can be twisted to the left (counterclockwise) or to the right (clockwise).

[0268] The optical properties of the first and second layers in the second embodiment of the optical anisotropic layer are not particularly limited. However, when the thickness of the first layer is set to d1 and the refractive index anisotropy of the first layer measured at a wavelength of 550 nm is set to Δn1, from the viewpoint that the optical anisotropic layer can be preferably applied to a circular polarizer, the first layer preferably satisfies the following formula (1B-1).

[0269] Equation (1B-1): 205nm ≤ Δn1d1 ≤ 345nm Among them, it is more preferable to satisfy equation (1B-2), and even more preferable to satisfy equation (1B-3).

[0270] Equation (1B-2): 225nm ≤ Δn1d1 ≤ 325nm Equation (1B-3) 245nm≤Δn1d1≤305nm When the thickness of the second layer in the second embodiment is set to d2 and the anisotropy of the refractive index of the second layer measured at a wavelength of 550 nm is set to Δn2, from the viewpoint that the optical anisotropy layer can be preferably applied to a circular polarizer, the second layer preferably satisfies the following formula (2B-1).

[0271] Equation (2B-1) 70nm≤Δn2d2≤210nm Among them, it is more preferable to satisfy equation (2B-2), and even more preferable to satisfy equation (2B-3).

[0272] Equation (2B-2): 90nm ≤ Δn²d² ≤ 190nm Equation (2B-3) 110nm≤Δn2d2≤170nm There is no particular limitation on the absolute value of the twist angle of the liquid crystal compound in the first layer, but from the viewpoint that the optical anisotropy layer can be preferably applied to a circular polarizer, it is preferable to be greater than 0° and less than 60°, and more preferably 10 to 50°.

[0273] The absolute value of the twist angle of the liquid crystal compound in the second layer is not particularly limited, but from the viewpoint that the optical anisotropy layer can be preferably applied to a circular polarizer, it is preferably 50 to 110°, and more preferably 60 to 100°.

[0274] The optical properties of the first and second layers in the second embodiment of the optical anisotropy layer are not particularly limited, but it is preferable that they satisfy the optical properties of the first and second optical anisotropy layers (the relationship between the twist angle, Δn1d1, Δn2d2, and slow axis of the liquid crystal compound) as described in claim 1 or claim 5 of Japanese Patent No. 5753922.

[0275] The second embodiment of the optical anisotropic layer preferably represents reverse wavelength dispersion.

[0276] 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).

[0277] The manufacturing method of the second embodiment of the optical anisotropic layer is not particularly limited, but examples can be given of increasing the absolute value of the weighted average helical torsion force of the chiral reagent in the composition layer formed by the above-described step 1A (for example, exceeding 0 μm). -1 The method is as follows. When the absolute value of the weighted average helical torsional force of the chiral reagent in the composition layer formed through step 1A is large, firstly, as... Figure 11 As shown, in the composition layer 302 on the substrate 18 where step 2A has been performed, the liquid crystal compound is twisted and oriented along a helical axis extending in the thickness direction. If steps 3A and 4A are performed on this composition layer, then in regions of the composition layer with low oxygen concentration ( Figure 12 In the lower region 302A, the twisted orientation of the liquid crystal compound is directly fixed in the region of the composition layer with high oxygen concentration. Figure 12 The spiral torsion force changes in the upper region 302B, so that after the implementation of process 5A, layers with different torsion angles of liquid crystal compounds can be formed.

[0278] <<Third Implementation>> In the third embodiment of the optical anisotropic layer, the first layer and the second layer are optical anisotropic layers formed by fixing a cholesterol-type liquid crystal phase, and the helical pitch of the cholesterol-type liquid crystal phase in the first layer is different from that in the second layer.

[0279] exist Figure 13An example of a third embodiment of the optical anisotropic layer is shown.

[0280] Figure 13 The optically anisotropic layer 400 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 layer 400A and a second layer 400B along the thickness direction. In the first layer 400A and the second layer 400B, the helical pitch of the cholesterol-type liquid crystal phase is different, with the helical pitch of the second layer 400B being larger than that of the first layer 400A. Therefore, the selective reflection center wavelength of the cholesterol-type liquid crystal phase originating from the first layer 400A is different from that of the cholesterol-type liquid crystal phase originating from the second layer 400B. For example, the optically anisotropic layer can be an optically anisotropic layer having a layer fixed with a cholesterol-type liquid crystal phase that reflects blue light and a layer fixed with a cholesterol-type liquid crystal phase that reflects green light along the thickness direction, or it can be an optically anisotropic layer having a layer fixed with a cholesterol-type liquid crystal phase that reflects green light and a layer fixed with a cholesterol-type liquid crystal phase that reflects red light along the thickness direction.

[0281] The optically anisotropic layer preferably has at least two layers selected from the group consisting of a layer formed by fixing a cholesterol-type liquid crystal phase that reflects blue light, a layer formed by fixing a cholesterol-type liquid crystal phase that reflects green light, and a layer formed by fixing a cholesterol-type liquid crystal phase that reflects red light.

[0282] Furthermore, in this specification, the selection of the reflection center wavelength refers to setting T as the minimum value of the transmittance in the material (component) to be targeted. min In the case of (%), the half-value transmittance expressed by the following formula is used: T 1 / 2 The average value of the two wavelengths (%).

[0283] The formula for calculating half-value transmittance is: T 1 / 2 =100-(100-T min )÷2 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).

[0284] The first layer 400A and the second layer 400B contained in the optical anisotropy layer 400 exhibit selective reflection of circularly polarized light of either right-handed or left-handed direction and transmission of circularly polarized light of the other direction.

[0285] The selective reflection center wavelength λ of a cholesterol-type liquid crystal phase depends on the pitch P (= the period of the helix) of the helical structure 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.

[0286] In addition, in this specification, the term "helix direction" is sometimes used to refer to the twisting direction of the helix of the cholesterol-type liquid crystal phase. When the twisting direction (helix direction) of the helix of 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 helix direction is to the left, it reflects left-handed circularly polarized light and transmits right-handed circularly polarized light.

[0287] Furthermore, the helical orientation of the cholesterol-type liquid crystal phase in the optical anisotropic layer is preferably the same in layers with different helical pitches.

[0288] 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, the 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 and published by Sigma in 2007, page 46, and in "Liquid Crystal Handbook," edited by Maruzen of the Liquid Crystal Handbook Editorial Committee, page 196.

[0289] The manufacturing method of the third embodiment of the optical anisotropic layer is not particularly limited, but a manufacturing method including the following steps 1B to 5B is preferred.

[0290] Step 1B: 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 and a liquid crystal compound having polymerizable groups. Step 2B: 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. Step 3B: After step 2B, under conditions where the oxygen concentration is 1% by volume or higher, the composite layer is subjected to 300 mJ / cm 2 The following process involves light irradiation for less than 50 seconds. 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. Step 5B: After step 4B, the composite layer is cured to form an optically anisotropic layer. As described later, in the third embodiment, in order to manufacture an optically anisotropic layer with the above-described properties, the total content of chiral reagents in the composition layer (the total content of all chiral reagents) is preferably more than 5.0% by mass relative to the total mass of the liquid crystal compound.

[0291] The main difference between the first and third embodiments can be attributed to the content of the chiral reagent.

[0292] The steps of each of the above processes are described in detail below.

[0293] <Process 1B> Step 1B is the 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 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.

[0294] The chiral reagents (chiral reagent A and chiral reagent B) and liquid crystal compounds contained in the composition layer are as described in step 1A.

[0295] Furthermore, as described in step 1A above, the composition layer may contain other components besides chiral reagents and liquid crystal compounds.

[0296] In step 1B, a chiral reagent is included in the composition layer to form a cholesterol-type liquid crystal phase in step 2B described later.

[0297] In the second embodiment, the total content of chiral reagents in the composition layer (the total content of all chiral reagents) is not particularly limited. However, 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.

[0298] 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.

[0299] The absolute value of the helical torsional force of the chiral reagent in the composition layer formed by step 1B 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.

[0300] 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 1B is preferably within the above-mentioned range.

[0301] The weighted average helical torsional force is defined as described above.

[0302] Regarding the method for forming the composition layer in step 1B, a method identical to the method for forming the composition layer in step 1A described above can be cited.

[0303] <Process 2B> Step 2B involves heat-treating the composition layer to orient the liquid crystal compounds within it, thereby forming a cholesterol-type liquid crystal phase. By performing this step, the liquid crystal compounds in the composition layer achieve a predetermined orientation.

[0304] The optimal conditions for heat treatment are selected based on the liquid crystal compound used.

[0305] 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.

[0306] The heating time is typically 0.1 to 60 minutes, with 0.2 to 5 minutes being more common.

[0307] <Process 3B> 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 exposure will then last for 50 seconds or less. The mechanism of this process will now be described using the accompanying drawings.

[0308] like Figure 14 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 18 opposite to the side of the composition layer 402 ( Figure 14 The direction of the hollow arrow in the image is used for illumination. Additionally, in... Figure 14 In this process, light irradiation is performed from the substrate 18 side, but it can also be performed from the composition layer 402 side.

[0309] At this point, if we compare the lower region 402A on the substrate 18 side of the composition layer 402 with the upper region 402B on the opposite side of the substrate 18 side, the surface of the upper region 402B is on the air side, therefore the oxygen concentration in the upper region 402B is high, and the oxygen concentration in the lower region 402A is low. Therefore, if the composition layer 402 is irradiated with light, the liquid crystal compound is easily polymerized in the lower region 402A, and the orientation state of the liquid crystal compound is fixed. In addition, chiral reagent A is also present in the lower region 402A, 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 402A, even if the heat treatment step 4B on the light-irradiated composition layer described later is performed, no change in the orientation state of the liquid crystal compound will occur.

[0310] Furthermore, due to the high oxygen concentration in the upper region 402B, 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 402B, and therefore, the helical torsion force changes upon photosensitive reaction to chiral reagent A. Thus, if the subsequent step 4B is performed, the orientation state of the liquid crystal compound changes along with the altered helical torsion force.

[0311] That is, by performing step 3B, the alignment state of the liquid crystal compound can be easily fixed in the substrate-side region (lower region) of the composition layer. However, it is difficult to fix the alignment state of the liquid crystal compound in the region (upper region) on the opposite side of the composition layer from the substrate side, resulting in a state where the helical torsional force varies according to the photosensitive chiral reagent A.

[0312] The various conditions for light irradiation in process 3B (oxygen concentration, irradiation time, irradiation amount, etc.) are the same as those for light irradiation in process 3A above.

[0313] <Process 4B> Step 4B is as follows: After step 3B, the composition layer is heat-treated at a higher temperature than during light irradiation. By performing this step, the orientation state of the liquid crystal compound changes in the region where the helical torsional force of chiral reagent A changes in the light-irradiated composition layer. More specifically, this step is as follows: the composition layer after step 3B is heat-treated at a higher temperature than during irradiation to orient the liquid crystal compound in the composition layer that was not fixed in step 3B.

[0314] The mechanism of this process will be described below using the accompanying drawings.

[0315] As mentioned above, if for Figure 14In the embodiment of step 3B of the composition layer 402 shown, the orientation state of the liquid crystal compound is fixed in the lower region 402A, while polymerization of the liquid crystal compound is difficult to occur in the upper region 402B, 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 402B. 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 402B changes. This will be explained in more detail.

[0316] Furthermore, in the following description, the case in which the composition layer 402 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.

[0317] Light is irradiated in the upper region 402B of this state, such as... Figure 16 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 402B decreases.

[0318] Therefore, if the composition layer 402 after process 3B, where the helical torsional force changes, is subjected to heat treatment to promote the reorientation of the liquid crystal compound, then as... Figure 15 As shown, in the upper region 402B, the helical pitch of the cholesterol-type liquid crystal phase increases.

[0319] On the other hand, as described above, in the lower region 402A of the composition layer 402, 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.

[0320] As described above, by performing step 4B, multiple cholesterol-type liquid crystal phases with different helical pitches are formed along the thickness direction of the composition layer.

[0321] In addition, in the above Figure 14 and Figure 15 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.

[0322] Furthermore, in the above Figure 14 and Figure 15 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.

[0323] Furthermore, in the above Figure 14 and Figure 15The 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.

[0324] The heat treatment is carried out at a higher temperature than that under light irradiation.

[0325] 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.

[0326] 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.

[0327] The heating time is typically between 0.01 and 60 minutes, with 0.03 to 5 minutes being more common.

[0328] 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 .

[0329] 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 .

[0330] <Process 5B> Step 5B is as follows: After step 4B, the composition layer is cured to form an optically anisotropic layer. By performing this step, the orientation state of the liquid crystal compound 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 by fixing a cholesterol-type liquid crystal phase and having multiple layers with different helical pitches of the cholesterol-type liquid crystal phase along the thickness direction. The length of the helical pitch in each of the formed layers is often constant. That is, by performing this step, an optically anisotropic layer can be formed by fixing a cholesterol-type liquid crystal phase and having two layers with different helical pitches of the cholesterol-type liquid crystal phase along the thickness direction, with each layer having a constant helical pitch.

[0331] As a method for curing treatment in step 5B, the method for curing treatment in step 5A can be cited as an example.

[0332] <<Fourth Implementation>> In the fourth embodiment of the optical anisotropic layer, the first layer and the second layer are optical anisotropic layers formed by fixing the orientation state of the liquid crystal compound. The tilt angle of the orientation direction of the liquid crystal compound in the first layer relative to the layer surface is different from the tilt angle of the orientation direction of the liquid crystal compound in the second layer relative to the layer surface.

[0333] exist Figure 17 An example of the fourth embodiment of the optical anisotropic layer is shown in the figure.

[0334] Figure 17 The optical anisotropic layer 500 shown is an optical anisotropic layer formed by fixing the orientation state of the liquid crystal compound LC, and has a first layer 500A and a second layer 500B along the thickness direction. The first layer 500A is a layer formed by fixing the orientation state of the liquid crystal compound in parallel orientation (horizontal orientation), and the second layer 500B is a layer formed by fixing the orientation state of the liquid crystal compound in vertical orientation (homeotropic alignment).

[0335] In this specification, vertical 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 perpendicular to the layer surface and aligned in the same orientation (optical uniaxiality).

[0336] 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.

[0337] 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°.

[0338] When the thickness of the first layer 500A is set to d1 and the in-plane refractive index anisotropy of the first layer 500A measured at a wavelength of 550nm is set to Δn1, from the viewpoint that the optical anisotropy layer can be preferably applied to a circular polarizer, the first layer preferably satisfies the following formula (1C-1).

[0339] Equation (1C-1) 100nm≤Δn1d1≤180nm More preferably, equation (1C-2) is satisfied.

[0340] Equation (1C-2) 110nm≤Δn1d1≤170nm Furthermore, when the thickness of the second layer 500B is set to d2 and the in-plane refractive index anisotropy of the second layer 500B 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, the second layer 500B preferably satisfies the following formula (2C-1).

[0341] Equation (2C-1) 0nm≤Δn2d2≤30nm More preferably, equation (2C-2) is satisfied.

[0342] Equation (2C-2): 0nm≤Δn2d2≤20nm The thickness retardation of the second layer 500B at a wavelength of 550nm is preferably -150 to -20nm, more preferably -120 to -20nm.

[0343] The fourth embodiment of the optical anisotropic layer preferably represents reverse wavelength dispersion.

[0344] 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).

[0345] The optical properties of the fourth embodiment of the optical anisotropic layer are not particularly limited, but it is preferred to function as a λ / 4 plate.

[0346] 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.

[0347] 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.

[0348] In the above method, an optically anisotropic layer having a layer in which the orientation state of a vertically oriented liquid crystal compound is fixed and a layer in which the orientation state of a parallel-oriented liquid crystal compound is fixed along the thickness direction has been described in detail. However, it is not limited to this method as long as the optically anisotropic layer contains two layers in which the orientation direction of the liquid crystal compound has different tilt angles relative to the layer surface.

[0349] For example, the optical anisotropic layer can be an optical anisotropic layer having a layer that fixes the orientation state of a tilted liquid crystal compound and a layer that fixes the orientation state of a parallel liquid crystal compound.

[0350] The manufacturing method of the fourth embodiment of the optical anisotropic layer is not particularly limited, but a manufacturing method including the following steps 1C to 5C is preferred.

[0351] Step 1C: The step of forming a composition layer, said composition layer comprising a photosensitive compound whose polarity changes upon light irradiation and a liquid crystal compound having polymerizable groups. Step 2C: A step of heat-treating the composition layer to orient the liquid crystal compounds in the composition layer. Step 3C: After step 2C, under conditions where the oxygen concentration is 1% by volume or higher, the composite layer is subjected to 300 mJ / cm 2 The following process involves light irradiation for less than 50 seconds. Step 4C: After step 3C, a heat treatment is performed on the composition layer at a higher temperature than that during light irradiation. Step 5C: After step 4C, the composite layer is cured to form an optically anisotropic layer. In the fourth embodiment, as described later, a photosensitive compound whose polarity changes upon exposure to light is used.

[0352] The steps of each of the above processes are described in detail below.

[0353] <Process 1C> Step 1C is the step of forming a composition layer, which comprises 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.

[0354] The liquid crystal compound contained in the composition layer is as described in step 1A.

[0355] Furthermore, as described in step 1A above, the composition layer may contain other components.

[0356] (Photosensitive compounds whose polarity changes upon exposure to light) The composition layer of step 1C contains a photosensitive compound whose polarity changes upon light irradiation (hereinafter also referred to as "specific photosensitive compound").

[0357] 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 1C, the polarity of the specific photosensitive compound changes in the air-side region of the composition layer, and thus, during step 4C, the orientation direction of the liquid crystal compound is tilted or perpendicular to the layer surface as its polarity changes.

[0358] 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.

[0359] 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.

[0360] 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.

[0361] The preferred photosensitive compound is the compound represented by formula (X).

[0362] [Chemical Formula 6] In the above formula (X), T represents an aromatic hydrocarbon group with an n+m valence. Sp represents a single bond or a divalent linker. Hb represents a fluorinated alkyl group with 4 to 30 carbon atoms. m represents an integer from 1 to 4. n represents an integer from 1 to 4. A represents the group represented by the following formula (Y), [Chemical Formula 7] In the above formula (Y), R1 to R5 each independently represent a hydrogen atom or a monovalent substituent. Indicates the bonding site.

[0363] 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.

[0364] In the above formula (X), T represents an aromatic hydrocarbon group with an n+m valence.

[0365] 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.

[0366] 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, or iodine atoms), cyano groups, and acyloxy groups (e.g., acetoxy groups).

[0367] In the above formula (X), Sp represents a single bond or a divalent linking group, preferably a divalent linking group.

[0368] 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 groups" shown below.

[0369] 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.

[0370] (Divalent organic groups) 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.

[0371] Furthermore, R6 above represents an alkyl group having 1 to 6 hydrogen atoms or carbon atoms.

[0372] 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.

[0373] In the above formula (X), Hb represents a fluorinated alkyl group with 4 to 30 carbon atoms.

[0374] 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.

[0375] As a fluorinated alkyl group, the structure of a perfluoroalkyl group is preferred.

[0376] In the above formula (X), the preferred manner of the group represented by -Sp-Hb is illustrated below.

[0377] Additionally, in the following examples, Indicates the connection position with T.

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

[0379] Furthermore, the total number of carbon atoms in the portion excluding the perfluorinated group is preferably 10 or less.

[0380] In the above formula (X), n and m independently represent integers from 1 to 4.

[0381] From the viewpoint of further hydrophilization, n is preferably 2 or more. m is preferably 1 to 3, and more preferably 2.

[0382] In the above formula (X), A represents the group represented by the above formula (Y).

[0383] The following is an explanation of equation (Y).

[0384] 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.

[0385] Examples of substituents representing the monovalent group R1 to R4 include halogen atoms (e.g., fluorine, chlorine, bromine, and iodine), 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., -N(R)). 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 with 1 to 5 carbon atoms). It can also be represented by -C(=O)N(R). D )2 (2 Rs) D Each of these groups independently represents a hydrogen atom or a monovalent organic group (e.g., an alkyl group with 1 to 5 carbon atoms). Other groups include alkoxy carbonyl groups with 2 to 8 carbon atoms (e.g., -C(=O)OCH3), acyloxy groups with 2 to 8 carbon atoms (e.g., -OC(=O)CH3), and -Sp groups. A -Hb A .

[0386] 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.

[0387] Among them, R1 to R4 are preferably independently hydrogen atom, halogen atom, hydroxyl group, cyano group, alkoxy group, -NH2, -NH(CH3), -N(CH3)2, -C(=O)OCH3, -OC(=O)CH3, -NHC(=O)CH3, -N(CH3)C(=O)CH3 or -Sp A -Hb A .

[0388] 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 opposite side of the bonded side (in other words, the end of the side connected to the benzene ring of formula (Y)) contains ether oxygen, the effect of accelerating the decomposition rate can be obtained in the same way as -OCH3 above.

[0389] Furthermore, from the viewpoint of further accelerating the decomposition rate of the compound represented by the exposure-based formula (X) 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 .

[0390] 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.

[0391] 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).

[0392] In addition, in equation (Y), there are multiple representations of -Sp in R1 to R4. B -Hb BIn the case where there are multiple Sp B Hb and the existence of multiple Hb B They can be the same or different.

[0393] 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).

[0394] Equation (Z) (C) p F 2p+1 )-(CH2) q -O-(CH2) r -O- 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.

[0395] In the above formula (Y), R5 is preferably a hydrogen atom, methyl, ethyl or aromatic group.

[0396] 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.

[0397] 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.

[0398] Furthermore, in the above formula (Y), This indicates the bonding site with C(=O)O- in the above formula (X).

[0399] The compound represented by the above formula (X) can be a compound with a symmetrical molecular structure or a compound without a 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.

[0400] 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.

[0401] 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).

[0402] From the viewpoint that it is easier to form an optically anisotropic layer with a specified structure, the content of the specific photosensitive compound is preferably 0.01 to 10% by mass relative to the total mass of the liquid crystal compound, and more preferably 0.05 to 5% by mass.

[0403] 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 specific photosensitive compound and a liquid crystal compound having polymerizable groups 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.

[0404] The coating method is described in detail below.

[0405] The composition used in the coating method includes the aforementioned specific photosensitive compound, a liquid crystal compound having polymerizable groups, and other components used as needed (e.g., polymerization initiators, polymerizable monomers, surfactants, and polymers).

[0406] The content of each component in the composition is preferably adjusted to the content of each component in the above-mentioned composition layer.

[0407] 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.

[0408] 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.

[0409] 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.

[0410] <Process 2C> 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 18 As shown, for example, by performing step 2C, the liquid crystal compound is aligned in parallel in the composition.

[0411] The optimal conditions for heat treatment are selected based on the liquid crystal compound used.

[0412] 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.

[0413] The heating time is typically 0.1 to 60 minutes, with 0.2 to 5 minutes being more common.

[0414] <Process 3C> Step 3C is as follows: After step 2C, under conditions where the oxygen concentration is 1% by volume or higher, the composition layer is subjected to 300 mJ / cm 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 18 In this composition, the liquid crystal compound (LC) is oriented in parallel within the composite layer.

[0415] like Figure 18 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 18 opposite to the side of the composition layer 502 ( Figure 18 The direction of the hollow arrow in the image is used for illumination. Additionally, in... Figure 18 In this process, light irradiation is performed from the substrate 18 side, but it can also be performed from the composition layer 502 side.

[0416] At this point, if we compare the lower region 502A on the substrate 18 side of the composition layer 502 with the upper region 502B on the opposite side of the substrate 18 side, the surface of the upper region 502B is on the air side, therefore the oxygen concentration in the upper region 502B is high, and the oxygen concentration in the lower region 502A is low. Therefore, if the composition layer 502 is irradiated with light, the liquid crystal compound readily polymerizes in the lower region 502A, and the orientation state of the liquid crystal compound is fixed. Furthermore, a specific photosensitive compound is also present in the lower region 502A, and this photosensitive compound also undergoes photosensitive hydrophilication. However, since the orientation state of the liquid crystal compound is fixed in the lower region 502A, even if the heat treatment step 4C, which will be described later, is performed on the light-irradiated composition layer, no change in the orientation state of the liquid crystal compound will occur.

[0417] Furthermore, due to the high oxygen concentration in the upper region 502B, 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 502B, and this photosensitive compound becomes hydrophilic upon light exposure. Therefore, if step 4C is performed later, the orientation state of the liquid crystal compound changes due to the altered polarity.

[0418] 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, resulting in a state where the polarity changes depending on the specific photosensitive compound.

[0419] 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.

[0420] <Process 4C> Step 4C is as follows: After step 3C, 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 3C 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 3C.

[0421] The mechanism of this process will be described below using the accompanying drawings.

[0422] As mentioned above, if for Figure 18 In step 3C of the composition layer 502 shown, the orientation state of the liquid crystal compound is fixed in the lower region 502A, while polymerization of the liquid crystal compound is difficult to occur in the upper region 502B, and the orientation state of the liquid crystal compound is not fixed. Furthermore, a specific photosensitive compound in the upper region 502B becomes hydrophilic upon light exposure. If this polarity changes, the orientation direction of the liquid crystal compound in the upper region 502B 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.

[0423] In cases where the composition layer contains a specific photosensitive compound that becomes hydrophilic upon light irradiation, such as Figure 19As shown, if step 4C is performed, the liquid crystal compound is vertically oriented in the upper region 502B. 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.

[0424] On the other hand, as described above, in the lower region 502A of the composition layer 502, the liquid crystal compound is polymerized during step 3C and the orientation state of the liquid crystal compound is fixed, so the reorientation of the liquid crystal compound is not performed.

[0425] As described above, by performing step 4C, a region containing a liquid crystal compound whose orientation is tilted or perpendicular to the layer surface can be formed.

[0426] In addition, in the above Figure 19 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.

[0427] The heat treatment is carried out at a higher temperature than that under light irradiation.

[0428] 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.

[0429] 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.

[0430] The heating time is typically between 0.01 and 60 minutes, with 0.03 to 5 minutes being more common.

[0431] <Process 5C> Step 5C is as follows: After step 4C, the composition layer is cured to form an optically anisotropic layer. 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 two layers along the thickness direction with different tilt angles relative to the layer surface for their orientation directions. In particular, by performing this step, an optically anisotropic layer can be formed having a layer along the thickness direction in which the orientation states of vertically oriented or tilted liquid crystal compounds are fixed, and a layer in which the orientation state of parallel-oriented liquid crystal compounds is fixed.

[0432] As a method for curing treatment in process 5C, the method for curing treatment in process 5A can be cited as an example.

[0433] <<Fifth Implementation>> In the fifth embodiment of the optical anisotropic layer, the first layer is a layer formed by fixing the orientation state of the liquid crystal compound, and the second layer is a layer formed by fixing the state of the liquid crystal compound displaying an isotropic phase.

[0434] exist Figure 20 An example of the fifth embodiment of the optical anisotropic layer is shown.

[0435] Figure 20 The optical anisotropic layer 600 shown is an optical anisotropic layer formed using a liquid crystal compound, and has a first layer 600A and a second layer 600B along the thickness direction. The first layer 600A is a layer formed by fixing the orientation state of the parallel-aligned liquid crystal compound, and the second layer 600B is a layer formed by fixing the state of the liquid crystal compound displaying an isotropic phase.

[0436] In the above Figure 20 The text describes an optically anisotropic layer having, along its thickness direction, a layer that fixes the orientation of parallel-oriented liquid crystal compounds and a layer that fixes the state of the liquid crystal compounds displaying an isotropic phase. However, the text is not limited to this method as long as it includes a layer that fixes the state of the liquid crystal compounds displaying an isotropic phase. For example, it could be an optically anisotropic layer having, along its thickness direction, a layer that fixes the orientation of vertically oriented liquid crystal compounds and a layer that fixes the state of the liquid crystal compounds displaying an isotropic phase. It could also be an optically anisotropic layer formed using a liquid crystal compound and having, along its thickness direction, a layer that fixes a cholesterol-type liquid crystal phase and a layer that fixes the state of the liquid crystal compounds displaying an isotropic phase. Furthermore, it could also be an optically anisotropic layer having a layer that fixes the orientation of a liquid crystal compound twisted along a helical axis extending along its thickness direction and a layer that fixes the state of the liquid crystal compounds displaying an isotropic phase.

[0437] The optical properties of the fifth embodiment of the optical anisotropic layer are not particularly limited, but it is preferred to function as a λ / 4 plate.

[0438] 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.

[0439] 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.

[0440] The manufacturing method of the fifth embodiment of the optical anisotropic layer is not particularly limited, but a manufacturing method including the following steps 1D to 5D is preferred.

[0441] Step 1D: The step of forming a composition layer, said composition layer comprising a liquid crystal compound having polymerizable groups. Process 2D: The process of heat-treating the composition layer to orient the liquid crystal compounds in the composition layer. Process 3D: After process 2D, 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. Process 4D: After process 3D, a heat treatment process is performed on the composition layer at a temperature higher than that during light irradiation, where the liquid crystal compound becomes an isotropic phase. Process 5D: After process 4D, the composite layer is cured to form an optically anisotropic layer. The steps of each of the above processes are described in detail below.

[0442] <Process 1D> Step 1D is a step of forming a composition layer comprising a liquid crystal compound having polymerizable groups. By performing this step, a composition layer for undergoing the light irradiation treatment described later can be formed.

[0443] The liquid crystal compound contained in the composition layer is as described in step 1A.

[0444] Furthermore, as described in step 1A above, the composition layer may contain other components besides the liquid crystal compound.

[0445] In step 1A, a composition layer containing the above-described components is formed, but the steps are not particularly limited. For example, a method can be described in which a composition containing the above-described liquid crystal compound having polymerizable groups is coated onto a substrate and dried as needed (hereinafter, also simply referred to as the "coating method"), and another method can be described in which the composition layer is formed and transferred onto the substrate. Of these, from the viewpoint of productivity, the coating method is preferred.

[0446] The coating method is described in detail below.

[0447] 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).

[0448] The content of each component in the composition is preferably adjusted to the content of each component in the above-mentioned composition layer.

[0449] 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.

[0450] 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.

[0451] 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.

[0452] <Process 2D> Step 2D 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 21 As shown, for example, by implementing step 2D, the liquid crystal compound is aligned in parallel in the composition.

[0453] The optimal conditions for heat treatment are selected based on the liquid crystal compound used.

[0454] 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.

[0455] The heating time is typically 0.1 to 60 minutes, with 0.2 to 5 minutes being more common.

[0456] <Process 3D> Process 3D consists of the following steps: After process 2D, 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. Figure 21 In this composition, the liquid crystal compound (LC) is oriented in parallel within the composite layer.

[0457] like Figure 21 As shown, in process 3D, under conditions where the oxygen concentration is 1% by volume or higher, the direction from the side of the substrate 18 opposite to the side of the composition layer 602 ( Figure 21 The direction of the hollow arrow in the image is used for illumination. Additionally, in... Figure 21 In this process, light irradiation is performed from the substrate 18 side, but it can also be performed from the composition layer 602 side.

[0458] At this point, if we compare the lower region 602A on the substrate 18 side of the composition layer 602 with the upper region 602B on the opposite side of the substrate 18 side, the surface of the upper region 602B is on the air side. Therefore, the oxygen concentration in the upper region 602B is high, while the oxygen concentration in the lower region 602A is low. Therefore, if the composition layer 602 is irradiated with light, the liquid crystal compound readily polymerizes in the lower region 602A, and the orientation state of the liquid crystal compound is fixed. Therefore, even if step 4D, which describes the heat treatment of the light-irradiated composition layer, is performed later, no change in the orientation state of the liquid crystal compound will occur.

[0459] Furthermore, due to the high oxygen concentration in the upper region 602B, the polymerization of the liquid crystal compound is hindered by oxygen even when exposed to light, making polymerization difficult. Therefore, if the following step 4D is performed, the orientation state of the liquid crystal compound changes.

[0460] That is, by performing process 3D, 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 process 4D described later.

[0461] The various conditions of light irradiation in process 3D (oxygen concentration, irradiation time, irradiation amount, etc.) are the same as those in process 3A above.

[0462] <Process 4D> Step 4D is as follows: After step 3D, the composition layer is heat-treated 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.

[0463] The mechanism of this process will be described below using the accompanying drawings.

[0464] As mentioned above, if for Figure 21 In the embodiment of process 3D of the composition layer 602 shown, the orientation state of the liquid crystal compound is fixed in the lower region 602A, while it is difficult to polymerize the liquid crystal compound in the upper region 602B, and the orientation state of the liquid crystal compound is not fixed.

[0465] Therefore, if process 4D is implemented, then as follows Figure 22 As shown, no polymerization of the liquid crystal compound occurs in the upper region 602B, so the orientation state of the liquid crystal compound is destroyed and it becomes an isotropic phase.

[0466] On the other hand, as described above, in the lower region 602A of the composition layer 602, the liquid crystal compound is polymerized during process 3D and the orientation state of the liquid crystal compound is fixed, so the reorientation of the liquid crystal compound is not performed.

[0467] As described above, by performing process 4D, an optically anisotropic layer can be formed having a layer in the thickness direction that fixes the orientation state (e.g., parallel orientation state) of the liquid crystal compound and a layer that fixes the unoriented state (isotropic phase of the liquid crystal compound).

[0468] 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.

[0469] 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.

[0470] 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 set as 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 common.

[0471] The heating time is typically between 0.01 and 60 minutes, with 0.03 to 5 minutes being more common.

[0472] <Process 5D> Step 5D is as follows: After step 4D, the composition layer is cured to form an optically anisotropic layer. By performing this step, the orientation state of the liquid crystal compound in the composition layer is fixed, resulting in the formation of a specified optically anisotropic layer.

[0473] As an example of a curing process in process 5D, the curing process in process 5A can be cited.

[0474] <<Applications>> Optical anisotropic layers can be combined with various components.

[0475] For example, the aforementioned optical anisotropic layer can be combined with other optical anisotropic layers. That is, such as... Figure 23 As shown, a laminate 24 comprising a substrate 18, the aforementioned optical anisotropic layer 10, and other optical anisotropic layers 22 can be fabricated. Furthermore, Figure 23 The laminate 24 described herein includes a substrate 18, but the laminate may also exclude the substrate.

[0476] 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).

[0477] 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.

[0478] In addition, in this specification, the A-board and C-board are defined as follows.

[0479] 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.

[0480] Equation (A1) nx>ny≈nz Equation (A2) ny<nx≈nz 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”.

[0481] 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.

[0482] Equation (C1) nz>nx≈ny Equation (C2) nz<nx≈ny 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 thickness of the film) is 0 to 10 nm, preferably 0 to 5 nm, is also included in “nx≈ny”.

[0483] 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 to obtain a laminate by laminating an optically anisotropic layer obtained by the manufacturing method of the present invention with other optically anisotropic layers (e.g., a C-plate). 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.

[0484] Furthermore, the optical anisotropic layer obtained using the manufacturing method of the present invention can be combined with a polarizer. That is, as... Figure 24 As shown, a polarizer-equipped optical anisotropy layer 28 can be fabricated, including a substrate 18, the aforementioned optical anisotropy layer 10, and a polarizer 26. Figure 24 In this case, a polarizer 26 is disposed on the substrate 18, but it is not limited to this method. A polarizer 26 may also be disposed on the optical anisotropic layer 10.

[0485] and, Figure 24 The optical anisotropy layer 28 with polarizer described herein includes a substrate 18, but the optical anisotropy layer with polarizer may not include a substrate.

[0486] 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.

[0487] 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.

[0488] In addition, protective films can be configured on one or both sides of the polarizer.

[0489] 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.

[0490] 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.

[0491] 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.

[0492] 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.

[0493] 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.

[0494] 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.

[0495] 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.

[0496] Example 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.

[0497] <Example 1> (Fabrication of cellulose acylate membrane (substrate)) 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).

[0498] ------------------------------------------------------------- Cellulose acylate doped solution ------------------------------------------------------------- Cellulose acylated compound (acetyl substitution degree 2.86, viscosity-uniform polymerization degree 310) 100 parts by weight Sugar ester compound 1 (chemical formula (S4)) 6.0 parts by mass Sugar ester compound 2 (chemical formula (S5)) 2.0 parts by mass 0.1 parts by weight of silica particle dispersion (AEROSIL R972, manufactured by NIPPON AEROSIL CO.,LTD.) Solvents (dichloromethane / methanol / butanol) ------------------------------------------------------------- [Chemical Formula 8] [Chemical Formula 9] The dopant solution prepared in the above manner was cast using a roller film casting machine. After co-casting the dopant solution used to form the core layer and the dopant solution used to form the surface layer on the core layer from the mold and bringing them into contact with a metal support cooled to 0°C, the obtained film was peeled off. The roller was made of SUS (Steel Use Stainless).

[0499] The film, peeled from the rollers, was conveyed using a tenter frame that clamps both ends of the film and then dried at 30–40°C for 20 minutes. Next, the resulting film was post-dried by zone heating while being conveyed by rollers. Afterward, the resulting film was knurled and then wound up.

[0500] The obtained elongated 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.

[0501] (Formation of an anisotropic optical layer) The cellulose acylated membrane produced in the above manner 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 80°. 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 10°. In other words, the position of the rotation axis of the friction roller is that of a position rotated 80° clockwise from the length direction of the cellulose acylated membrane.

[0502] Using a die coater, an optically anisotropic layer forming composition (A) containing the aforementioned rod-shaped liquid crystal compound is coated onto the film subjected to the above-described rubbing treatment, thereby forming a composition layer (corresponding to step 1A). Furthermore, the absolute value of the weighted average helical torsional force of the chiral reagent in the composition layer of step 1A is 0.0 μm. -1 .

[0503] 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.

[0504] Subsequently, in oxygen-containing air (oxygen concentration: approximately 20% by volume), at 40°C, ultraviolet light was applied to the composition layer for 1 second using a 365nm LED lamp (manufactured by Acroedge Co., Ltd.) (corresponding to step 3A). At this time, the maximum in-plane irradiation dose was 13.2 mJ / cm². 2 The minimum value is 12.9 mJ / cm. 2 .

[0505] Next, the obtained composition layer was heated at 90°C for 10 seconds (corresponding to step 4A).

[0506] Subsequently, the composite layer was subjected to ultraviolet irradiation (irradiation dose: 500 mJ / cm²) at 55°C under a nitrogen atmosphere using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.). 2 An optical anisotropic layer (corresponding to step 5A) is formed to fix the orientation state of the liquid crystal compound, thereby producing an optical film (A).

[0507] ------------------------------------------------------------- Composition for forming optical anisotropic layers (A) ------------------------------------------------------------- • 80 parts by weight of the following rod-shaped liquid crystal compound (A) • 10 parts by weight of the following rod-shaped liquid crystal compound (B) • 10 parts by weight of the following rod-shaped liquid crystal compound (C) • Ethylene oxide modified trimethylolpropane triacrylate (V#360, manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.) 4 parts by weight • Photopolymerization initiator (Irgacure 819, manufactured by Ciba Japan) 3 parts by weight • 0.42 parts by weight of the following chiral reagent (A) • 0.38 parts by weight of the following chiral reagent (B) • 0.5 parts by weight of the following polymer (X) • 0.08 parts by weight of the following polymer (A) • 117 parts by weight of methyl isobutyl ketone • 39 parts by weight of ethyl propionate ------------------------------------------------------------- Rod-shaped liquid crystal compound (A) (hereinafter, a mixture of compounds) [Chemical Formula 10] Rod-shaped liquid crystal compound (B) [Chemical Formula 11] Rod-shaped liquid crystal compound (C) [Chemical Formula 12] Chiral reagent (A) [Chemical Formula 13] (Chiral reagent B) [Chemical Formula 14] Polymer (X) (where the value recorded in each repeating unit represents the content (mass%) of each repeating unit relative to all repeating units.) [Chemical Formula 15] Polymer (A) (where the values ​​recorded in each repeating unit represent the content (mass%) of each repeating unit relative to all repeating units.) [Chemical Formula 16] The optical film (A) fabricated in the above manner was cut parallel to the friction direction, and the optical anisotropy layer was observed from the cross-sectional direction using a polarizing microscope. The optical anisotropy layer consists of two layers exhibiting different optical anisotropy. The cellulose acylate film-side layer (layer 1) in the optical anisotropy layer is a layer with a thickness (d1) of 1310 nm, in which a liquid crystal compound with parallel orientation is fixed. The air-side layer (layer 2) in the optical anisotropy layer is a layer with a thickness (d2) of 1390 nm, in which a liquid crystal compound with a twisted orientation with the thickness direction as the helical axis is fixed.

[0508] In addition, the optical properties of the optical film (A) were determined using Axometrics' Axoscan and Axometrics' Multi-Layer Analysis software. The product of Δn1 and thickness d1 (Δn1d1) at a wavelength of 550 nm for the first layer is 173 nm, the twist angle of the liquid crystal compound is 0°, and the orientation axis angle of the liquid crystal compound relative to the length direction of the film is -10° on the side in contact with the substrate and -10° on the side in contact with the second layer.

[0509] Furthermore, the product of Δn2 and thickness d2 (Δn2d2) at a wavelength of 550nm in the second layer is 184nm, the twist angle of the liquid crystal compound is 75°, and the orientation axis angle of the liquid crystal compound relative to the length direction of the film is -10° on the side in contact with the first layer and -85° on the air side.

[0510] In addition, the orientation axis angle of the liquid crystal compound contained in the optical anisotropic layer is set to 0° with the length direction of the film as the reference. When viewing 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.

[0511] Furthermore, regarding the twisted structure of the liquid crystal compound, when observing the substrate from the surface side of the optical anisotropic layer, with the orientation direction of the liquid crystal compound on the surface side (front side) as a reference, the orientation direction of the liquid crystal compound on the substrate side (inner side) is represented as negative when it is clockwise (right turn) and positive when it is counterclockwise (left turn).

[0512] (Fabrication of a circular polarizer) A polyvinyl alcohol (PVA) film with a thickness of 80 μm was stained by immersing it in an aqueous iodine solution with a concentration of 0.05% by mass for 60 seconds at 30 °C. The resulting film was then longitudinally stretched to five times its original length by immersing it in an aqueous boric acid solution with a concentration of 4% by mass for 60 seconds, and subsequently dried at 50 °C for 4 minutes to obtain a polarizer with a thickness of 20 μm.

[0513] (Fabrication of polarizer protective film) A commercially available cellulose acylated membrane, "TD80UL" (manufactured by Fujifilm Corporation), was prepared by immersing it in a 1.5 mol / L sodium hydroxide aqueous solution at 55°C, followed by thorough rinsing with water. Next, it was immersed in a 0.005 mol / L dilute sulfuric acid aqueous solution at 35°C for 1 minute, and then rinsed thoroughly with water to remove the sulfuric acid. Finally, the membrane was thoroughly dried at 120°C to produce a polarizer protective film.

[0514] A polarizer protective film prepared in the above manner is bonded to one side of a polarizer prepared in the above manner using a polyvinyl alcohol-based adhesive, thereby creating a laminate including a polarizer and a polarizer protective film disposed on one side of the polarizer.

[0515] An adhesive layer is formed by coating the polarizer (without a polarizer protective film) side of the laminate prepared in the above manner with an adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.), and then the optical film (A) prepared in the above manner is bonded to the cellulose acylate film in such a way that the adhesive layer is tightly bonded to the film. Furthermore, the angle formed between the absorption axis of the polarizer and the in-plane slow axis of the polarizer-side surface of the optical anisotropy layer in the optical film (A) is 10°.

[0516] Next, an adhesive is applied to the optical film (A) in the obtained laminate to form an adhesive layer.

[0517] Through the above steps, a strip-shaped circular polarizer (A) was fabricated, which was arranged in the order of polarizer protective film, polarizer, cellulose acylate film, optical anisotropic layer and adhesive layer.

[0518] <Example 2> When irradiated by a 365nm LED lamp (manufactured by Acroedge Co., Ltd.), the output was adjusted and the maximum in-plane irradiance was set to 13.3 mJ / cm². 2 The minimum value is set to 12.7 mJ / cm. 2 In addition, an optical film (B) and a circular polarizer (B) were fabricated using the same steps as in Example 1.

[0519] <Example 3> (Formation of an anisotropic optical layer) 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°.

[0520] Using a die coater, an optical anisotropic layer forming composition (B) containing the following rod-shaped liquid crystal compound is coated onto the film that has undergone the above-mentioned rubbing treatment, thereby forming a composition layer.

[0521] 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.

[0522] Subsequently, in oxygen-containing air (oxygen concentration: approximately 20% by volume), at 40°C, ultraviolet light was applied to the composite layer for 1 second using a 365nm LED lamp (manufactured by Acroedge Co., Ltd.). At this point, the maximum in-plane irradiation dose was 16.2 mJ / cm². 2 The minimum value is 15.8 mJ / cm. 2 .

[0523] Next, the obtained composition layer was heated at 90°C for 10 seconds.

[0524] Subsequently, the composite layer was subjected to ultraviolet irradiation (irradiation dose: 500 mJ / cm²) at 55°C under a nitrogen atmosphere using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.). 2 An optical anisotropic layer is formed by fixing the orientation state of the liquid crystal compound, thereby creating an optical film (C).

[0525] ------------------------------------------------------------- Composition for forming optical anisotropic layers (B) ------------------------------------------------------------- • 80 parts by weight of the above rod-shaped liquid crystal compound (A) • 10 parts by mass of the above-mentioned rod-shaped liquid crystal compound (B) • 10 parts by mass of the above rod-shaped liquid crystal compound (C) • Ethylene oxide modified trimethylolpropane triacrylate (V#360, manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.) 4 parts by weight • Photopolymerization initiator (Irgacure 819, manufactured by Ciba Japan) 3 parts by weight • 0.44 parts by weight of the above chiral reagent (A) • 0.31 parts by weight of the above chiral reagent (B) • 0.5 parts by weight of the above polymer (X) • 0.08 parts by weight of the above polymer (A) • 117 parts by weight of methyl isobutyl ketone • 39 parts by weight of ethyl propionate ------------------------------------------------------------- The optical film (C) fabricated in the above manner was cut parallel to the friction direction, and the optical anisotropy layer was observed from the cross-sectional direction using a polarizing microscope. The optical anisotropy layer consists of two layers exhibiting different optical anisotropy. The cellulose acylate film-side layer (layer 1) in the optical anisotropy layer is a layer with a thickness (d1) of 2090 nm, in which a liquid crystal compound is fixed with a twisted orientation along the thickness direction. The air-side layer (layer 2) in the optical anisotropy layer is a layer with a thickness (d2) of 1050 nm, in which a liquid crystal compound is fixed with a twisted orientation along the thickness direction.

[0526] In addition, the optical properties of the optical film (C) were determined using Axometrics' Axoscan and Axometrics' Multi-Layer Analysis software. The product of Δn1 and thickness d1 (Δn1d1) at a wavelength of 550 nm for the first layer is 275 nm, the twist angle of the liquid crystal compound is 26°, and the orientation axis angle of the liquid crystal compound relative to the length direction of the film is 0° on the side in contact with the substrate and -26° on the side in contact with the second layer.

[0527] Furthermore, the product of Δn2 and thickness d2 (Δn2d2) at a wavelength of 550nm in the second layer is 138nm, the twist angle of the liquid crystal compound is 78°, and the orientation axis angle of the liquid crystal compound relative to the length direction of the film is -26° on the side in contact with the first layer and -104° on the air side.

[0528] In addition, the orientation axis angle of the liquid crystal compound contained in the optical anisotropic layer is set to 0° with the length direction of the film as the reference. When viewing 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.

[0529] Furthermore, regarding the twisted structure of the liquid crystal compound, when observing the substrate from the surface side of the optical anisotropic layer, with the orientation direction of the liquid crystal compound on the surface side (front side) as a reference, the orientation direction of the liquid crystal compound on the substrate side (inner side) is represented as negative when it is clockwise (right turn) and positive when it is counterclockwise (left turn).

[0530] (Fabrication of a circular polarizer) A polarizer protective film prepared in the above manner is bonded to one side of a polarizer prepared in the above manner using a polyvinyl alcohol-based adhesive, thereby creating a laminate including a polarizer and a polarizer protective film disposed on one side of the polarizer.

[0531] An adhesive layer is formed by coating the polarizer (without a polarizer protective film) side of the laminate prepared in the above manner with an adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.), and then the optical film (C) prepared in the above manner is bonded to the cellulose acylate film in such a way that the adhesive layer is tightly bonded to the optical film. In addition, the absorption axis of the polarizer is parallel to the in-plane slow axis of the substrate side surface of the first layer of the optical anisotropy layer in the optical film (C).

[0532] Next, an adhesive is applied to the optical film (C) in the obtained laminate to form an adhesive layer.

[0533] Through the above steps, a strip-shaped circular polarizer (C) was fabricated, which was arranged in the order of polarizer protective film, polarizer, cellulose acylate film, optical anisotropic layer and adhesive layer.

[0534] <Example 4> (Alkali saponification treatment) After passing the cellulose acylated membrane prepared by the method described in Example 1 through a dielectric heating roller at a temperature of 60°C to raise the membrane surface temperature to 40°C, an alkaline solution of the composition shown below is coated at a coating amount of 14 ml / m using a bar coater. 2The 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.

[0535] ------------------------------------------------------------- alkaline solution ------------------------------------------------------------- 4.7 parts by weight of potassium hydroxide 15.8 parts by weight of water 63.7 parts by weight of isopropanol Surfactant: C 14 H 29 O(CH2CH2O) 20 H 1.0 parts by weight 14.8 parts by weight of propylene glycol ------------------------------------------------------------- (Formation of the orientation film) 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.

[0536] ------------------------------------------------------------- Orientation film coating solution ------------------------------------------------------------- The following modified polyvinyl alcohol 28 parts by weight Citrate ester (AS3, manufactured by SANKYO CHEMICAL Co., Ltd.) 1.2 parts by weight Photopolymerization initiator (Irgacure 2959, manufactured by BASF) 0.84 parts by weight 2.8 parts by weight of glutaraldehyde 699 parts by weight of water 226 parts by weight of methanol ------------------------------------------------------------- (Modified polyvinyl alcohol) [Chemical Formula 17] (Formation of an anisotropic optical layer) 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.

[0537] Using the cellulose acylate film with an orientation film that has undergone the above-mentioned friction treatment as a substrate, an optical anisotropic layer forming composition (C) 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).

[0538] Next, the obtained composition layer was heated at 120°C for 80 seconds (corresponding to step 2C). Through this heating, the rod-shaped liquid crystal compound of the composition layer was oriented in a predetermined direction.

[0539] Subsequently, in oxygen-containing air (oxygen concentration: approximately 20% by volume), at 40°C, ultraviolet light was applied to the composition layer for 1 second using a 365nm LED lamp (manufactured by Acroedge Co., Ltd.) (corresponding to step 3C). At this point, the maximum in-plane irradiation dose was 16.8 mJ / cm². 2 The minimum value is 16.3 mJ / cm. 2 .

[0540] Next, the obtained composition layer was heated at 90°C for 10 seconds (corresponding to step 4C).

[0541] Subsequently, the composite layer was subjected to ultraviolet irradiation (irradiation dose: 500 mJ / cm²) at 55°C under a nitrogen atmosphere using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.).2 An optical anisotropic layer (corresponding to step 5C) is formed to fix the orientation state of the liquid crystal compound, thereby producing an optical film (D).

[0542] Composition for forming optical anisotropic layers (C) ------------------------------------------------------------- • 40 parts by weight of the following rod-shaped liquid crystal compound (D) • 40 parts by weight of the following rod-shaped liquid crystal compound (E) • 20 parts by weight of the above rod-shaped liquid crystal compound (A) • Ethylene oxide modified trimethylolpropane triacrylate (V#360, manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.) 4 parts by weight • Photopolymerization initiator (Irgacure 819, manufactured by Ciba Japan) 3 parts by weight • 0.5 parts by weight of the above polymer (X) • 0.08 parts by weight of the above polymer (A) • 3.0 parts by weight of the following ionic compound (A) • 0.4 parts by weight of the following photosensitive compound (A) • 156 parts by weight of methyl ethyl ketone ------------------------------------------------------------- Rod-shaped liquid crystal compounds (D) [Chemical Formula 18] Rod-shaped liquid crystal compounds (E) [Chemical Formula 19] Ionic compound (A) [Chemical Formula 20] Photosensitive compound (A) [Chemical Formula 21] Furthermore, the fluorine-containing compound (A) in the composition (C) for forming an optical anisotropic layer is exposed to irradiation (16.6 mJ / cm²). 2When exposed to 365nm light, it produces a decomposition product (A) with a hydrophilic carboxyl group.

[0543] Decomposition products (A) [Chemical Formula 22] The optical film (D) fabricated in the above manner was cut parallel to the friction direction, and the optical anisotropy layer was observed from the cross-sectional direction using a polarized light microscope. The optical anisotropy layer consists of two layers exhibiting different optical anisotropy. The cellulose acylate film-side layer (layer 1) in the optical anisotropy layer is a layer with a thickness (d1) of 3000 nm that fixes parallel-oriented liquid crystal compounds, while the air-side layer (layer 2) in the optical anisotropy layer is a layer with a thickness (d2) of 1300 nm that fixes vertically oriented liquid crystal compounds.

[0544] In addition, the optical properties of the optical film (D) were determined using Axometrics' Axoscan and Axometrics' Multi-Layer Analysis software. The product of Δn1 and d1 (Δn1d1) at a wavelength of 550 nm for the first layer is 140 nm, and the angle of the in-plane slow axis relative to the length direction of the film is -45°.

[0545] Furthermore, the product of Δn2 and d2 (Δn2d2) at a wavelength of 550nm in the second layer is 0nm, and the delay at a wavelength of 550nm in the thickness direction is -60nm.

[0546] 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.

[0547] (Fabrication of a circular polarizer) A polarizer protective film prepared in the above manner is bonded to one side of a polarizer prepared in the above manner using a polyvinyl alcohol-based adhesive, thereby creating a laminate including a polarizer and a polarizer protective film disposed on one side of the polarizer.

[0548] An adhesive layer is formed by coating the polarizer (without a polarizer protective film) side of the laminate prepared in the above manner with an adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.), and then the optical film (D) prepared in the above manner is bonded to the cellulose acylate film in such a way that the adhesive layer is tightly bonded to the film. Furthermore, the angle formed between the absorption axis of the polarizer and the in-plane slow axis of the optical anisotropy layer in the optical film (D) is 45°.

[0549] Next, an adhesive is applied to the optical film (D) in the obtained laminate to form an adhesive layer.

[0550] Through the above steps, a strip-shaped circular polarizer (D) was fabricated, arranged in the order of polarizer protective film, polarizer, cellulose acylate film, optical anisotropic layer and adhesive layer.

[0551] <Example 5> (Formation of an anisotropic optical layer) 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°.

[0552] Using the cellulose acylate film subjected to the above-described friction treatment as a substrate, an optical anisotropic layer forming composition (D) 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 1B). Furthermore, the absolute value of the helical torsional force of the chiral reagent in the composition layer of step 1B is 31 μm. -1 .

[0553] Next, the obtained composition layer was heated at 100°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.

[0554] Subsequently, in oxygen-containing air (oxygen concentration: approximately 20% by volume), at 40°C, ultraviolet light was applied to the composition layer for 1 second using a 365nm LED lamp (manufactured by Acroedge Co., Ltd.) (corresponding to step 3B). At this time, the maximum in-plane irradiation dose was 13.4 mJ / cm². 2 The minimum value is 13.1 mJ / cm. 2 .

[0555] Next, the obtained composition layer was heated at 90°C for 10 seconds (corresponding to step 4B).

[0556] Subsequently, the composite layer was subjected to ultraviolet irradiation (irradiation dose: 500 mJ / cm²) at 55°C under a nitrogen atmosphere using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.). 2 An optical anisotropy layer (corresponding to step 5B) is formed to fix the orientation state of the liquid crystal compound, thereby fabricating an optical film (E).

[0557] Composition of the composition (D) for forming an optical anisotropic layer ------------------------------------------------------------- • 80 parts by weight of the above rod-shaped liquid crystal compound (A) • 10 parts by mass of the above-mentioned rod-shaped liquid crystal compound (B) • 10 parts by mass of the above rod-shaped liquid crystal compound (C) • Ethylene oxide modified trimethylolpropane triacrylate (V#360, manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.) 4 parts by weight • Photopolymerization initiator (Irgacure 819, manufactured by Ciba Japan) 3 parts by weight • 11 parts by weight of the above chiral reagent (B) • 0.5 parts by weight of the above polymer (X) • 0.08 parts by weight of the above polymer (A) • 117 parts by weight of methyl isobutyl ketone • 39 parts by weight of ethyl propionate ------------------------------------------------------------- The optical film (E) 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 consists of two layers exhibiting different optical anisotropy. The thickness (d1) of the cellulose acylate film side layer (layer 1) in the optical anisotropic layer is 1800 nm, and the thickness (d2) of the air side layer (layer 2) in the optical anisotropic layer is 1800 nm. Furthermore, layers 1 and 2 are cholesterol orientations with different helical pitches.

[0558] Furthermore, the spectral reflectance characteristics of the optical film (E) 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 the first layer and a reflection band centered at 650 nm originating from the second layer.

[0559] <Example 6> (Formation of an anisotropic optical layer) 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.

[0560] Using the cellulose acylate film that has undergone the above-mentioned friction treatment as a substrate, an optical anisotropic layer forming composition (E) 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 1D).

[0561] Next, the obtained composition layer was heated at 80°C for 60 seconds (corresponding to step 2D). Through this heating, the rod-shaped liquid crystal compound of the composition layer was oriented in a predetermined direction.

[0562] Subsequently, in oxygen-containing air (oxygen concentration: approximately 20% by volume), at 40°C, ultraviolet light was applied to the composition layer for 1 second using a 365nm LED lamp (manufactured by Acroedge Co., Ltd.) (corresponding to step 3B). At this time, the maximum in-plane irradiation dose was 11.9 mJ / cm². 2 The minimum value is 11.6 mJ / cm. 2 .

[0563] Next, the obtained composition layer was heated at 130°C for 10 seconds (corresponding to step 4D). In addition, the phase transition temperature of the rod-shaped liquid crystal compound in the optical anisotropic layer formation composition (D) to the isotropic phase is 110°C.

[0564] Subsequently, the composite layer was irradiated with ultraviolet light (500 mJ / cm²) at 130°C under a nitrogen atmosphere using a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.). 2 An optical anisotropic layer (corresponding to step 5D) is formed to fix the orientation state of the liquid crystal compound, thereby fabricating an optical film (F).

[0565] Composition for forming optical anisotropic layers (E) ------------------------------------------------------------- • 80 parts by weight of the above rod-shaped liquid crystal compound (A) • 10 parts by mass of the above-mentioned rod-shaped liquid crystal compound (B) • 10 parts by mass of the above rod-shaped liquid crystal compound (C) • Ethylene oxide modified trimethylolpropane triacrylate (V#360, manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.) 4 parts by weight • Photopolymerization initiator (Irgacure 819, manufactured by Ciba Japan) 3 parts by weight • 0.5 parts by weight of the above polymer (X) • 0.08 parts by weight of the above polymer (A) • 117 parts by weight of methyl isobutyl ketone • 39 parts by weight of ethyl propionate ------------------------------------------------------------- The optical film (F) 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 a polarized light microscope. The optical anisotropic layer consists of two layers exhibiting different optical anisotropy. The cellulose acylate film-side layer (layer 1) in the optical anisotropic layer has a thickness (d1) of 1100 nm and is formed by fixing parallel-oriented liquid crystal compounds. The air-side layer (layer 2) in the optical anisotropic layer has a thickness (d2) of 1600 nm and the liquid crystal compounds are in an isotropic state (isotropic phase).

[0566] Furthermore, the optical properties of the optical film (F) were determined using Axometrics' Axoscan and its Multi-Layer Analysis software. For the first layer, the product of Δn1 and thickness d1 at a wavelength of 550 nm (Δn1d1) is 140 nm, and the in-plane slow axis is -45°. For the second layer, the product of Δn2 and thickness d2 at a wavelength of 550 nm (Δn2d2) (in-plane delay at 550 nm) is 0 nm, and the thickness-direction delay at 550 nm is also 0 nm.

[0567] 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.

[0568] (Fabrication of a circular polarizer) A polarizer protective film prepared in the above manner is bonded to one side of a polarizer prepared in the above manner using a polyvinyl alcohol-based adhesive, thereby creating a laminate including a polarizer and a polarizer protective film disposed on one side of the polarizer.

[0569] An adhesive layer is formed by coating the polarizer (without a polarizer protective film) side of the laminate prepared in the above manner with an adhesive (SK-2057, manufactured by Soken Chemical & Engineering Co., Ltd.), and then the optical film (F) prepared in the above manner is bonded to the cellulose acylate film in such a way that the adhesive layer is tightly bonded to the film. Furthermore, the angle formed between the absorption axis of the polarizer and the in-plane slow axis of the optical anisotropy layer in the optical film (F) is 45°.

[0570] Next, an adhesive is applied to the optical film (F) in the obtained laminate to form an adhesive layer.

[0571] Through the above steps, a long strip-shaped circular polarizer (F) was fabricated, arranged in the order of polarizer protective film, polarizer, cellulose acylate film, optical anisotropic layer and adhesive layer.

[0572] <Comparative Example 1> (Formation of an anisotropic optical layer) The cellulose acylated membrane produced in the above manner 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 72°. 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 18°. In other words, the position of the rotation axis of the friction roller is a position rotated 72° clockwise from the length direction of the cellulose acylated membrane.

[0573] Using the cellulose acylate film that has undergone the above-mentioned friction treatment as a substrate, an optical anisotropic layer forming composition (F) containing a rod-shaped liquid crystal compound with the following composition is coated using a die coater, thereby forming a composition layer.

[0574] Next, the obtained composition layer was heated at 100°C for 80 seconds.

[0575] Subsequently, the composite layer was irradiated under nitrogen atmosphere at 55°C (irradiation dose: 500 mJ / cm²). 2 The light from a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) is used to immobilize the liquid crystal compound, thereby forming an optically anisotropic layer.

[0576] Using a die coater, an optical anisotropic layer forming composition (G) comprising a rod-shaped liquid crystal compound with the following composition is coated onto an optical anisotropic layer prepared in the manner described above, thereby forming a composition layer.

[0577] Next, the obtained composition layer was heated at 100°C for 80 seconds.

[0578] Subsequently, the composite layer was irradiated under nitrogen atmosphere at 55°C (irradiation dose: 500 mJ / cm²). 2 The light from a metal halide lamp (manufactured by EYE GRAPHICS Co., Ltd.) is used to immobilize liquid crystal compounds to form an optically anisotropic layer, thereby creating an optical film (G).

[0579] ------------------------------------------------------------- Composition for forming optical anisotropic layers (F) ------------------------------------------------------------- • 80 parts by weight of the above rod-shaped liquid crystal compound (A) • 10 parts by mass of the above-mentioned rod-shaped liquid crystal compound (B) • 10 parts by mass of the above rod-shaped liquid crystal compound (C) • Ethylene oxide modified trimethylolpropane triacrylate (V#360, manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.) 4 parts by weight • Photopolymerization initiator (Irgacure 819, manufactured by Ciba Japan) 3 parts by weight • 0.5 parts by weight of the above polymer (X) • 117 parts by weight of methyl isobutyl ketone • 39 parts by weight of ethyl propionate ------------------------------------------------------------- ------------------------------------------------------------- Composition for forming optical anisotropic layers (G) ------------------------------------------------------------- • 80 parts by weight of the above rod-shaped liquid crystal compound (A) • 10 parts by mass of the above-mentioned rod-shaped liquid crystal compound (B) • 10 parts by mass of the above rod-shaped liquid crystal compound (C) • Ethylene oxide modified trimethylolpropane triacrylate (V#360, manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.) 4 parts by weight • Photopolymerization initiator (Irgacure 819, manufactured by Ciba Japan) 3 parts by weight • 0.6 parts by weight of the above chiral reagent (A) • 0.08 parts by weight of the above polymer (A) • 156 parts by weight of methyl ethyl ketone ------------------------------------------------------------- The optical film (G) fabricated in the above manner was cut parallel to the friction direction, and the optical anisotropy layer was observed from the cross-sectional direction using a polarizing microscope. The optical anisotropy layer consists of two layers exhibiting different optical anisotropy. The cellulose acylate film-side layer (layer 1) in the optical anisotropy layer is a layer with a thickness (d1) of 1310 nm, in which a liquid crystal compound with parallel orientation is fixed. The air-side layer (layer 2) in the optical anisotropy layer is a layer with a thickness (d2) of 1390 nm, in which a liquid crystal compound with a twisted orientation with the thickness direction as the helical axis is fixed.

[0580] In addition, the optical properties of the optical film (A) were determined using Axometrics' Axoscan and Axometrics' Multi-Layer Analysis software. The product of Δn1 and thickness d1 (Δn1d1) at a wavelength of 550 nm for the first layer is 173 nm, the twist angle of the liquid crystal compound is 0°, and the orientation axis angle of the liquid crystal compound relative to the length direction of the film is -10° on the side in contact with the substrate and -10° on the side in contact with the second layer.

[0581] Furthermore, the product of Δn2 and thickness d2 (Δn2d2) at a wavelength of 550nm in the second layer is 184nm, the twist angle of the liquid crystal compound is 75°, and the orientation axis angle of the liquid crystal compound relative to the length direction of the film is -10° on the side in contact with the first layer and -85° on the air side.

[0582] In addition, the orientation axis angle of the liquid crystal compound contained in the optical anisotropic layer is set to 0° with the length direction of the film as the reference. When viewing 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.

[0583] Furthermore, regarding the twisted structure of the liquid crystal compound, when observing the substrate from the surface side of the optical anisotropic layer, with the orientation direction of the liquid crystal compound on the surface side (front side) as a reference, the orientation direction of the liquid crystal compound on the substrate side (inner side) is represented as negative when it is clockwise (right turn) and positive when it is counterclockwise (left turn).

[0584] (Fabrication of a circular polarizer) An optical film (G) was used instead of an optical film (A), and otherwise a circular polarizer (G) was fabricated following the same steps as in Example 1.

[0585] <Comparative Example 2> When irradiating a 365nm LED lamp (manufactured by Acroedge Co., Ltd.), the output was adjusted and the maximum in-plane irradiance was set to 13.7 mJ / cm². 2 The minimum value is set to 12.4 mJ / cm. 2 In addition, an optical film (H) and a circular polarizer (H) were fabricated using the same steps as in Example 1.

[0586] <Evaluation> (The thickness of the optical anisotropic layer is not uniform) Following the steps described above, in each of the 64 grid regions in which the largest square obtained on the surface of the optical anisotropic layer in the optical film (A) to (H) is uniformly divided into 8 parts along the longitudinal and transverse directions, the optical anisotropic layer is cut through the center of the aforementioned sub-region and parallel to the friction direction. The thickness d1 of the first layer and the thickness d2 of the second layer are measured from the exposed cross-section, and the maximum value (Xmax), minimum value (Xmin), and ratio (Xmax / Xmin) of the proportion X (=d1 / (d1+d2)) of the thickness d1 in the total layer thickness (d1+d2) are calculated.

[0587] (Evaluation of Uneven Visibility in OLED Installation Methods (OLED Installation Evaluation)) The LG Electronics OLED55B8PJA, which is equipped with an organic EL panel (organic EL display element), was disassembled. The touch panel with a circular polarizer was peeled off from the organic EL display device. The circular polarizers (A) to (D) and (F) to (H), which were made in the above manner, were bonded together to prevent air from entering in order to manufacture an organic EL display device. The visibility of color unevenness was evaluated.

[0588] A: The unevenness is completely invisible (allowed). B: Although some unevenness is visible, it is very slight (permissible). C: Visible unevenness, unacceptable. (Evaluation of non-uniform visibility under diffused light source (reflection evaluation)) The fabricated optical film (E) was placed under a diffused light source, and the visibility of the reflected color was evaluated.

[0589] A: The unevenness is completely invisible (allowed). B: Although some unevenness is visible, it is very slight (permissible). C: Visible unevenness, unacceptable. In Table 1, "parallel" indicates that the liquid crystal compound is parallel to the orientation. "Twisted" indicates that the liquid crystal compound is twisted along a helical axis extending in the thickness direction. "Vertical" indicates that the liquid crystal compound is vertically oriented. "Cholesterol-type" indicates that the liquid crystal compound is cholesterol-oriented. "Isotropic phase" indicates that the liquid crystal compound exhibits an isotropic phase.

[0590] As shown in the table above, the optical anisotropic layer of the present invention exhibits the desired effect.

[0591] By comparing Example 1 and Example 2, it was confirmed that a better effect can be obtained when the relationship of Equation (2B) is satisfied.

[0592] Symbol Explanation 10, 100, 200, 300, 400, 500, 600 - Optical anisotropic layers; 12, 102, 200A, 300A, 400A, 500A, 600A - First layer; 14, 104, 200B, 300B, 400B, 500B, 600B - Second layer; 16 - Sub-region; 18 - Substrate; 22 - Other optical anisotropic layers; 24 - Laminated layer; 26 - Polarizer; 28 - Optical anisotropic layer with polarizer; 202, 302, 402, 502, 602 - Composite layer; 202A, 302A, 402A, 502A, 602A - Lower region; 202B, 302B, 402B, 502B, 602B - Upper region.

Claims

1. An optically anisotropic layer formed using a liquid crystal compound, wherein, The optical anisotropic layer has a first layer and a second layer in direct contact with the first layer along the thickness direction. The orientation state of the liquid crystal compound in the first layer is different from that of the liquid crystal compound in the second layer. The region within the largest square that can be depicted on the surface of the optical anisotropic layer is subdivided into 64 sub-regions of equal area. The thickness d1 of the first layer and the thickness d2 of the second layer at the center of each sub-region are calculated. X represented by equation (1) is calculated for each sub-region. When the maximum value of the calculated 64 X values ​​is set as Xmax and the minimum value is set as Xmin, the relationship of equation (2A) is satisfied. The first layer is formed by fixing the orientation state of parallel-aligned liquid crystal compounds. Equation (1) X=d1 / (d1+d2) Equation (2A) Xmax / Xmin < 1.

10.

2. The optical anisotropic layer according to claim 1, wherein the optical anisotropic layer exhibits inverse wavelength dispersion.

3. An optically anisotropic layer formed using a liquid crystal compound, wherein, The optical anisotropic layer has a first layer and a second layer in direct contact with the first layer along the thickness direction. The orientation state of the liquid crystal compound in the first layer is different from that of the liquid crystal compound in the second layer. The region within the largest square that can be depicted on the surface of the optical anisotropic layer is subdivided into 64 sub-regions of equal area. The thickness d1 of the first layer and the thickness d2 of the second layer at the center of each sub-region are calculated. X represented by equation (1) is calculated for each sub-region. When the maximum value of the calculated 64 X values ​​is set as Xmax and the minimum value is set as Xmin, the relationship of equation (2A) is satisfied. The second layer is formed by fixing the orientation state of the vertically oriented liquid crystal compound. The thickness retardation of the second layer at a wavelength of 550 nm is -150 to -20 nm. Equation (1) X=d1 / (d1+d2) Equation (2A) Xmax / Xmin < 1.

10.

4. The optical anisotropic layer according to claim 3, wherein, With the thickness of the second layer set to d2 and the in-plane refractive index anisotropy of the second layer measured at a wavelength of 550 nm set to Δn2, the second layer satisfies the following equation (2C-1). Equation (2C-1) 0nm≤Δn2d2≤30nm.

5. The optical anisotropic layer according to claim 3, wherein, The first layer is formed by fixing the orientation state of parallel-aligned liquid crystal compounds. When the thickness of the first layer is set to d1 and the anisotropy of the refractive index of the first layer measured at a wavelength of 550 nm is set to Δn1, the first layer satisfies equation (1A-1). Equation (1A-1) 100nm≤Δn1d1≤240nm.

6. The optical anisotropic layer according to claim 1 or 3, which satisfies the relationship of equation (2B), Equation (2B) Xmax / Xmin < 1.

09.

7. The optical anisotropic layer according to claim 1 or 3, wherein, The thickness of the first layer and the second layer is 0.1 to 5.

0.

8. The optical anisotropic layer according to claim 1 or 3, wherein, When the thickness of the first layer is set to d1 and the anisotropy of the refractive index of the first layer measured at a wavelength of 550 nm is set to Δn1, the first layer satisfies the following equation (1A). Equation (1A) 100nm≤Δn1d1≤200nm.

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