Optical element

Abstract

To provide an optical element in which alignment defects are suppressed; diffraction efficiency is improved; and light resistance under an air atmosphere is excellent.SOLUTION: An optical element is a cured film of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound (A) represented by a general formula (1) (the general formula (1-1) in the figure is one example thereof). The optical element has a liquid crystal alignment pattern in which the orientation of the optical axis originating from the polymerizable liquid crystal compound changes by rotating continuously along at least one in-plane direction. (In the formula, Z1 and Z2 independently represent a hydrogen atom, -CN, -NCS, a C1-10 alkoxy group, or a polymerizable group, provided that at least one of Z1 and Z2 represents a polymerizable group, and other symbols are as defined in the specification.)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to optical elements. [Background technology]

[0002] Polarized light is used in many optical devices or systems, and optical elements for controlling the reflection, focusing, and divergence of polarized light are being developed.

[0003] Patent Document 1 discloses an optical diffraction element formed by patterning a thin film containing a liquid crystal compound and having optical anisotropy. The element described in Patent Document 1, which diffracts light by changing the orientation pattern of rod-shaped liquid crystal compounds in a plane, is expected to be used as an optical component in augmented reality (AR) image projection devices and the like. However, conventionally known orientation patterns using liquid crystal compounds have a problem in that the diffraction efficiency decreases as the diffraction angle increases, i.e., the intensity of the diffracted light weakens. Therefore, there is a demand for an optical element that can obtain diffracted light at a large diffraction angle and with high diffraction efficiency.

[0004] Patent Document 2 aims to provide an optical element that can obtain diffracted light at a large diffraction angle and with higher diffraction efficiency than conventional optical elements, and discloses an optical element that includes a first optically anisotropic layer made of a cured layer of a composition containing a first liquid crystal compound, wherein the first optically anisotropic layer has a refractive index anisotropy Δn550 of 0.24 or more when measured with light having a wavelength of 550 nm, and has a first liquid crystal orientation pattern in which the direction of the optical axis derived from the first liquid crystal compound is continuously rotated along at least one direction in the plane, and wherein, when the length Λ over which the direction of the optical axis rotates 180° in the plane is defined as one period in the first liquid crystal orientation pattern, the length Λ of one period is 1.6 μm or less. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2017-522601 [Patent Document 2] International Publication No. 2020 / 022496 Summary of the Invention [Problem to be solved by the invention]

[0006] For example, the diffraction angle can be controlled by adjusting the pitch of the liquid crystal orientation pattern, which functions as a lens. The smaller the pitch of the liquid crystal orientation pattern, the larger the diffraction angle. However, in narrow pitch regions, the curvature of the liquid crystal alignment increases, causing a sudden change in the optical axis of the liquid crystal compound, resulting in a decrease in alignment, which in turn causes alignment defects and a decrease in diffraction efficiency. Furthermore, in Patent Document 2, the optical element is achieved by using a tolan-based liquid crystal compound containing a specific tolan (1,2-diphenylacetylene) structure as the first liquid crystal compound forming the first optically anisotropic layer. However, tolan-based liquid crystal compounds have problems with degradation and coloration due to light due to the influence of the triple bond. There is a concern that the tolan skeleton containing the triple bond may be oxidatively decomposed in the presence of oxygen, such as tolan → diketone → carboxylic acid. For practical use, optical elements are also required to have light resistance in an air atmosphere (in the presence of oxygen).

[0007] The present disclosure has been made in consideration of the above problems, and aims to provide an optical element in which orientation defects are suppressed, diffraction efficiency is improved, and light resistance in an air atmosphere is excellent. [Means for solving the problem]

[0008] The aspects of the present disclosure relate to the following [1] to [8]. [1] A polymerizable liquid crystal compound (A) represented by the following general formula (1): The liquid crystal display device further comprises an optically anisotropic layer which is a cured film of a polymerizable liquid crystal composition which may further contain a polymerizable liquid crystal compound (B) represented by the following general formula (2): An optical element, wherein a cured film of the polymerizable liquid crystal composition has a liquid crystal alignment pattern in which the direction of the optical axis derived from the polymerizable liquid crystal compound is continuously rotated and changed along at least one direction in the plane.

[0009] [ka] (In the general formulas (1) and (2), Z 1 , Z 2 , Z 3 , and Z 4 each independently represents a hydrogen atom, -CN, -NCS, an alkoxy group having 1 to 10 carbon atoms, or a polymerizable group, and Z 1 and Z 2 at least one of represents a polymerizable group; 3 and Z 4 At least one of these represents a polymerizable group. R sp1 , R sp2 , R sp3 , and R sp4 each independently represent an alkylene group having 1 to 20 carbon atoms in which one -CH2- or two or more non-adjacent -CH2- groups may each independently be replaced by -O-, -COO-, -OCO-, -OCO-O-, -CO-NH-, -NH-CO-, or -CH=CH-, or a single bond. L 1 , L 2 , L 3 , L 4 , L 5 , L 6 , L 7 , and L 8each independently represents -O-, -S-, -OCH2-, -CHO-, -CH2CH2-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -OCO-NH-, -NH-COO-, -NH-CO-NH-, -NH-O-, -O-NH-, -SCH2-, -CH2S-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -COO-CH2CH2-, -OCO-CH2CH2-, -CH2CH2-COO-, -CH2CH2-OCO-, -COO-CH2-, -OCO-CH2-, -CH2-COO-, -CH2-OCO-, -CH=CH-, or a single bond. Substituent E each independently represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylamino group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkanoyl group having 1 to 10 carbon atoms, an alkanoyloxy group having 1 to 10 carbon atoms, an alkanoylamino group having 1 to 10 carbon atoms, an alkanoylthio group having 1 to 10 carbon atoms, an alkyloxycarbonyl group having 2 to 10 carbon atoms, an alkylaminocarbonyl group having 2 to 10 carbon atoms, an alkylthiocarbonyl group having 2 to 10 carbon atoms, a hydroxy group, an amino group, a mercapto group, a carboxy group, a sulfo group, an amido group, a cyano group, a nitro group, a halogen atom, or a polymerizable group. However, when the above groups described as substituent E have -CH2-, substituent E also includes groups in which at least one of the -CH2-s in the above groups is replaced with -O-, -CO-, or -CH=CH-. Furthermore, when the above group described as the substituent E has a hydrogen atom, the substituent E also includes a group in which at least one of the hydrogen atoms contained in the above group is replaced with at least one selected from the group consisting of a fluorine atom and a polymerizable group. k1, k2, k3, and k4 each independently represent an integer of 0 to 4. n represents 1 or 2, m represents 1 or 3, and n' represents 0 or 1, and n×2+m+n'×2=5 is satisfied. L 2 , and L 3When there are a plurality of each of the groups, they may be the same or different, and when there are a plurality of each of the groups, they may be the same or different.

[0010] [2] The optical element according to [1], wherein the optically anisotropic layer has an absorption spectrum of 200 nm to 500 nm, and the maximum wavelength of the wavelengths at which the absorbance per 1.00 μm of layer thickness is 350 nm or less. [3] The optical element according to [1] or [2], wherein the optically anisotropic layer has an absorption maximum wavelength on the long wavelength side of 270 nm or more and 320 nm or less in an absorption spectrum of 200 nm to 500 nm. [4] The optical element according to any one of the above items [1] to [3], wherein the polymerizable liquid crystal compound (A) represented by the above general formula (1) satisfies at least one of the following (i) to (iii): (i) m is 1 or 3, at least one k1 is 1, and E is a methyl group, a methoxycarbonyl group, or an ethoxycarbonyl group. (ii) n is 1, m is 1, and n' is 1, and L 1 and L 4 At least one of is -O-CO-O-, -COO-, -OCO-, -O-, or -S-. (iii) n is 1, m is 1, and n' is 1, and L 2 and L 3 At least one of is —COO—CH2CH2—, —OCO—CH2CH2—, —CH2CH2—COO—, or —CH2CH2—OCO—. [5] The optical element according to any one of [1] to [4], wherein the optically anisotropic layer has a refractive index anisotropy Δn of 0.16 to 0.24 as measured with light having a wavelength of 550 nm. [6] The optical element according to any one of the above [1] to [5], wherein the optically anisotropic layer has a thickness of 1.00 μm or more. [7] The optical element according to any one of the above items [1] to [6], wherein in the optically anisotropic layer, the polymerizable liquid crystal compound is cholesterically aligned in the thickness direction. [8] The optical element according to any one of the above items [1] to [7], wherein the optically anisotropic layer is laminated on an alignment film having a concave-convex structure. [Effects of the Invention]

[0011] The present disclosure has the effect of providing an optical element that suppresses orientation defects, improves diffraction efficiency, and has excellent light resistance in an air atmosphere. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram schematically illustrating an embodiment of an optical element according to the present disclosure. [Figure 2] FIG. 2 is a plan view schematically illustrating an optically anisotropic layer of the optical element shown in FIG. [Figure 3] FIG. 10 is a diagram schematically illustrating another embodiment of the optical element of the present disclosure. [Figure 4] FIG. 10 is a plan view schematic diagram of another embodiment of the optical element of the present disclosure. [Figure 5] FIG. 2 is a plan view showing a pattern shape of an alignment film used in the examples. [Figure 6] FIG. 1 is a conceptual diagram for explaining a method for measuring light intensity. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments and examples of the present disclosure will be described with reference to the drawings. However, the present disclosure can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments and examples exemplified below. Furthermore, to clarify the explanation, the drawings may schematically depict the width, thickness, shape, etc. of each part compared to the actual form, but these are merely examples and do not limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings are given the same reference numerals, and detailed descriptions may be omitted as appropriate. Furthermore, for convenience of explanation, the terms "upper" and "lower" may be used in some cases, but the up-down direction may be reversed. "In this specification, when a certain component, such as a certain region, is said to be "on (or under)" another component, such as another component, or another region, unless otherwise specified, this includes not only the case where it is directly above (or directly below) the other component, but also the case where it is above (or below) the other component, i.e., the case where another component is included between the two components above (or below) the other component.

[0014] In the present disclosure, the alignment regulation force refers to the action of aligning the liquid crystal compound in the retardation layer in a specific direction. In the present disclosure, (meth)acrylic refers to either acrylic or methacrylic, and (meth)acrylate refers to either acrylate or methacrylate. Furthermore, in this specification, the terms "plate," "sheet," and "film" are not distinguished from one another solely on the basis of differences in name, and "film surface (plate surface, sheet surface)" refers to the surface that coincides with the planar direction of the target film-like (plate-like, sheet-like) member when the target film-like (plate-like, sheet-like) member is viewed overall and globally. In addition, in the present disclosure, the use of "to" indicating a numerical range means that the numerical values before and after it are included as the lower limit and upper limit.

[0015] [Optical elements] The present disclosure includes a polymerizable liquid crystal compound (A) represented by the following general formula (1): The liquid crystal display device further comprises an optically anisotropic layer which is a cured film of a polymerizable liquid crystal composition which may further contain a polymerizable liquid crystal compound (B) represented by the following general formula (2): A cured film of the polymerizable liquid crystal composition provides an optical element having a liquid crystal alignment pattern in which the direction of the optical axis derived from the polymerizable liquid crystal compound is continuously rotated along at least one direction in the plane.

[0016] [ka] (In the general formulas (1) and (2), Z 1 , Z 2 , Z3 , and Z 4 each independently represents a hydrogen atom, -CN, -NCS, an alkoxy group having 1 to 10 carbon atoms, or a polymerizable group, and Z 1 and Z 2 at least one of represents a polymerizable group; 3 and Z 4 At least one of these represents a polymerizable group. R sp1 , R sp2 , R sp3 , and R sp4 each independently represent an alkylene group having 1 to 20 carbon atoms in which one -CH2- or two or more non-adjacent -CH2- groups may each independently be replaced by -O-, -COO-, -OCO-, -OCO-O-, -CO-NH-, -NH-CO-, or -CH=CH-, or a single bond. L 1 , L 2 , L 3 , L 4 , L 5 , L 6 , L 7 , and L 8 each independently represents -O-, -S-, -OCH2-, -CHO-, -CH2CH2-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -OCO-NH-, -NH-COO-, -NH-CO-NH-, -NH-O-, -O-NH-, -SCH2-, -CH2S-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -COO-CH2CH2-, -OCO-CH2CH2-, -CH2CH2-COO-, -CH2CH2-OCO-, -COO-CH2-, -OCO-CH2-, -CH2-COO-, -CH2-OCO-, -CH=CH-, or a single bond. Substituent E each independently represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylamino group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkanoyl group having 1 to 10 carbon atoms, an alkanoyloxy group having 1 to 10 carbon atoms, an alkanoylamino group having 1 to 10 carbon atoms, an alkanoylthio group having 1 to 10 carbon atoms, an alkyloxycarbonyl group having 2 to 10 carbon atoms, an alkylaminocarbonyl group having 2 to 10 carbon atoms, an alkylthiocarbonyl group having 2 to 10 carbon atoms, a hydroxy group, an amino group, a mercapto group, a carboxy group, a sulfo group, an amido group, a cyano group, a nitro group, a halogen atom, or a polymerizable group. However, when the above groups described as substituent E have -CH2-, substituent E also includes groups in which at least one of the -CH2-s in the above groups is replaced with -O-, -CO-, or -CH=CH-. Furthermore, when the above group described as the substituent E has a hydrogen atom, the substituent E also includes a group in which at least one of the hydrogen atoms contained in the above group is replaced with at least one selected from the group consisting of a fluorine atom and a polymerizable group. k1, k2, k3, and k4 each independently represent an integer of 0 to 4. n represents 1 or 2, m represents 1 or 3, and n' represents 0 or 1, and n×2+m+n'×2=5 is satisfied. L 2 , and L 3 When there are a plurality of each of the groups, they may be the same or different, and when there are a plurality of each of the groups, they may be the same or different.

[0017] Figures 1 and 2 are diagrams schematically showing one embodiment of an optical element according to the present disclosure. Figure 1 is a side view schematically showing the layered structure of the optical element, and Figure 2 is a plan view schematically showing the liquid crystal orientation pattern of the optical element 100 shown in Figure 1. In the drawings, the sheet surface of the sheet-like optical element 100 is defined as the xy plane, and the thickness direction is defined as the z direction.

[0018] As shown in Fig. 1, an optical element 100 of one embodiment includes a support 1, an alignment film 5, and an optically anisotropic layer 10 composed of a cured film of a polymerizable liquid crystal composition. Although the optical element 100 of Fig. 1 includes the support 1 and the alignment film 5, the optical element 100 of this example of the disclosure may be configured with only the alignment film 5 and the optically anisotropic layer 10 by peeling off the support 1. Alternatively, the optical element 100 of this example of the disclosure may be configured with only the optically anisotropic layer 10 by peeling off both the support 1 and the alignment film 5.

[0019] 1, in order to simplify the drawing and clearly show the configuration of the optical element 100, only the polymerizable liquid crystal compound 20 (liquid crystal compound molecules) on the surface of the alignment film is shown schematically in the optically anisotropic layer 10. However, the optically anisotropic layer 10 has a structure in which aligned polymerizable liquid crystal compounds 20 are stacked, similar to an optically anisotropic layer formed using a normal liquid crystal composition.

[0020] 2, the optically anisotropic layer 10, which is a cured film of the polymerizable liquid crystal composition, has a liquid crystal alignment pattern in which the direction of the optical axis 20A derived from the polymerizable liquid crystal compound 20 changes while continuously rotating along at least one direction in the plane of the optically anisotropic layer 10. Here, the direction in which the optical axis 20A changes rotationally is aligned with the x-axis direction in the xy plane. In this embodiment, the direction in which the optical axis 20A changes rotationally is described as the x-direction.

[0021] The optical axis 20A derived from the polymerizable liquid crystal compound 20 is the axis along which the refractive index becomes the highest, that is, the so-called slow axis, in the polymerizable liquid crystal compound 20. As shown in Fig. 1, when the polymerizable liquid crystal compound 20 is a rod-shaped liquid crystal compound, the optical axis 20A is aligned with the long axis direction of the rod shape. In the following description, the optical axis 20A derived from the polymerizable liquid crystal compound 20 may be simply referred to as the optical axis 20A.

[0022] In the schematic plan view of the optical element 10 shown in FIG. 2, in order to clearly show the configuration of the optical element 100, only the polymerizable liquid crystal compound 20 on the surface of the alignment film 5 is shown, similarly to FIG.

[0023] The expression "the orientation of the optical axis 20A changes while continuously rotating in the x direction" specifically means that the angle between the optical axis 20A derived from the polymerizable liquid crystal compound 20 aligned along the x direction and the x direction varies depending on the position in the x direction, and the angle between the optical axis 20A and the x direction gradually changes along the x direction from θ to θ+180° or θ−180°. Here, "gradual change in angle" may mean a change at regular angle intervals or a continuous change. However, the difference in angle between the optical axes 20A derived from the polymerizable liquid crystal compound 20 adjacent to each other in the x direction is preferably 45° or less, more preferably 15° or less, and even more preferably a smaller angle.

[0024] On the other hand, the polymerizable liquid crystal compounds 20 forming the optically anisotropic layer 10 are arranged at equal intervals in the y direction perpendicular to the direction (x direction) in which the optical axis 20A continuously rotates within the plane, with the polymerizable liquid crystal compounds 20 having the same direction of the optical axis 20A being aligned. That is, in the polymerizable liquid crystal compounds 20 forming the optically anisotropic layer 10, the angles formed between the direction of the optical axis 20A and the x direction are equal to each other among the polymerizable liquid crystal compounds 20 aligned in the y direction.

[0025] In the optical element 10, in the liquid crystal orientation pattern of the polymerizable liquid crystal compound 20, the length (distance) over which the optical axis 20A rotates 180° in the x direction, in which the orientation of the optical axis 20A continuously rotates and changes in the plane, is defined as the length of one period of the liquid crystal orientation pattern. That is, the length of one period of the liquid crystal orientation pattern is defined as the distance from when the angle between the optical axis 20A derived from the polymerizable liquid crystal compound 20 and the x direction changes from θ to θ+180°. Specifically, as shown in FIG. 2, the distance between the centers in the x direction of the polymerizable liquid crystal compound 20 whose x direction and the direction of the optical axis 20A coincide is defined as the length of one period (pitch P). In the following description, this length of one period may be referred to as "one period P" or "pitch." In the optical element 100 of the present disclosure, the liquid crystal alignment pattern of the optically anisotropic layer 10 is a pattern in which this one period P of liquid crystal alignment is repeated in the x direction.

[0026] As described above, in the optically anisotropic layer 10, the angle between the optical axes 20A of the polymerizable liquid crystal compounds 20 aligned in the y direction and the x direction in which the optical axes of the polymerizable liquid crystal compounds 20 rotate is equal to one another. A region R is defined as a region in which the polymerizable liquid crystal compounds 20 aligned in the y direction have the same angle between their optical axes 20A and the x direction. In this case, the in-plane retardation (Re) value in each region R is preferably half the wavelength of the light (hereinafter referred to as "target light") to be diffracted by the optical element, i.e., λ / 2 when the wavelength of the target light is λ. These in-plane retardations are calculated by the product of the refractive index anisotropy Δn of region R and the thickness (layer thickness) d of the optically anisotropic layer. Here, the refractive index difference due to the refractive index anisotropy of region R in the optically anisotropic layer is defined as the difference between the refractive index in the direction of the slow axis in the plane of region R and the refractive index in the direction perpendicular to the slow axis. That is, the refractive index difference Δn due to the refractive index anisotropy of region R is equal to the difference between the refractive index of the polymerizable liquid crystal compound 20 in the direction of the optical axis 20A and the refractive index of the polymerizable liquid crystal compound 20 in the direction perpendicular to the optical axis 20A in the plane of region R. That is, the refractive index difference Δn depends on the polymerizable liquid crystal compound, and the in-plane retardation of each region R is approximately equal. However, as described above, the direction of the optical axis 20A differs between the regions R.

[0027] In the optically anisotropic layer 10, the direction of the optical axis 20A is rotated in the plane, making it difficult to measure the in-plane retardation of the entire layer. The retardation value of a cured film of the polymerizable liquid crystal composition obtained by applying the polymerizable liquid crystal composition, which is the raw material of the optically anisotropic layer 10, onto a support with an alignment film and fixing the composition so that the optical axis of the polymerizable liquid crystal composition is aligned horizontally to the surface of the support, and the thickness of the cured film are measured to determine the in-plane retardation. The in-plane retardation of the optically anisotropic layer 10 can be estimated from the period and the diffraction efficiency.

[0028] When circularly polarized light is incident on such an optically anisotropic layer 10, the light is refracted and the direction of the circularly polarized light is changed. When the in-plane retardation of the optically anisotropic layer 10 is λ / 2, when left-handed circularly polarized light enters the optically anisotropic layer 10, the incident light is given a phase difference of 180° as it passes through the optically anisotropic layer 10, and the transmitted light is converted to right-handed circularly polarized light. Furthermore, when the incident light, which is left-handed circularly polarized light, passes through the optically anisotropic layer 10, the absolute phase changes depending on the direction of the optical axis 20A of each polymerizable liquid crystal compound 20. At this time, the direction of the optical axis 20A changes while rotating along the x direction, so the amount of change in the absolute phase of the incident light, which is left-handed circularly polarized light, varies depending on the direction of the optical axis 20A. Furthermore, because the liquid crystal alignment pattern formed in the optically anisotropic layer 10 is a periodic pattern in the x direction, the incident light, which is left-handed circularly polarized light that has passed through the optically anisotropic layer 10, is given a periodic absolute phase in the x direction corresponding to the direction of each optic axis 20A. As a result, an equiphase surface tilted in the opposite direction to the x direction is formed. Therefore, the transmitted light is refracted so that it is tilted toward a direction perpendicular to the equiphase surface, and travels in a direction different from that of the incident light, which is left-handed circularly polarized. In this way, the incident light, which is left-handed circularly polarized, is converted into transmitted light that is right-handed circularly polarized, tilted at a certain angle in the x direction with respect to the incident direction.

[0029] On the other hand, when right-handed circularly polarized light is incident on the optically anisotropic layer 10 having the same in-plane retardation, the right-handed circularly polarized incident light passes through the optically anisotropic layer 10 and is converted into left-handed circularly polarized transmitted light that is tilted at a certain angle in the direction opposite to the x-direction with respect to the incident direction, in the same manner as described above.

[0030] As mentioned above, the in-plane retardation value of the optically anisotropic layer 10 is preferably half the wavelength of the target light. This is because the closer the in-plane retardation value is to half the wavelength of the target light, the higher the diffraction efficiency of the target light can be obtained. The in-plane retardation Re(λ) of the optically anisotropic layer for incident light with a wavelength of λ nm in the x direction is expressed as Re(λ)=Δn λ×d is preferably within the range defined by the following formula and can be set appropriately. 0.7×(λ / 2)nm≦Δn λ ×d≦1.3×(λ / 2)nm

[0031] By changing one period P of the liquid crystal orientation pattern formed in the optically anisotropic layer 10, it is possible to adjust the angle of refraction of transmitted right-handed circularly polarized light tilted by a certain angle or transmitted left-handed circularly polarized light tilted by a certain angle. Specifically, the shorter one period P of the liquid crystal orientation pattern is, the stronger the interference between lights passing through adjacent polymerizable liquid crystal compounds 20 becomes, and therefore the greater the refraction of the transmitted light can be. In other words, the smaller the pitch of the liquid crystal orientation pattern is, the greater the diffraction angle obtained.

[0032] However, as mentioned above, in narrow pitch regions, the curvature of the liquid crystal alignment becomes large, which causes a sudden change in the optical axis of the liquid crystal compound, resulting in a decrease in alignment, which in turn causes alignment defects and a decrease in diffraction efficiency. In contrast, in the optical element of the present disclosure, the optically anisotropic layer having a liquid crystal orientation pattern in which the direction of the optical axis derived from the polymerizable liquid crystal compound is continuously rotated and changed along at least one direction in the plane is an optically anisotropic layer that is a cured film of a polymerizable liquid crystal composition that contains the polymerizable liquid crystal compound (A) represented by the specific general formula (1) and may further contain the polymerizable liquid crystal compound (B) represented by the specific general formula (2), thereby suppressing orientation defects and improving diffraction efficiency. The polymerizable liquid crystal compound (A) represented by the specific general formula (1) is thought to be easily stacked due to the inclusion of a naphthalene structure, which increases the intermolecular interaction between the liquid crystal compounds, making alignment easier. Even when the polymerizable liquid crystal compound (A) represented by the specific general formula (1) contains the polymerizable liquid crystal compound (B) represented by the specific general formula (2), the naphthalene structure of the polymerizable liquid crystal compound (A) represented by the specific general formula (1) reduces the influence of steric hindrance, so the intermolecular interaction is stronger than the molecular interaction between the polymerizable liquid crystal compounds (B). This is thought to prevent a decrease in alignment even if the curvature of the liquid crystal alignment increases in a narrow pitch region. Furthermore, the polymerizable liquid crystal compound (A) represented by the specific general formula (1) and the polymerizable liquid crystal compound (B) represented by the specific general formula (2) do not contain a triple bond or a tolan structure. Therefore, an optical element including an optically anisotropic layer that is a cured film of the polymerizable liquid crystal composition used in the present disclosure has good light resistance in an air atmosphere (in the presence of oxygen). In view of light resistance in an air atmosphere, the polymerizable liquid crystal composition used for forming the optically anisotropic layer of the present disclosure does not need to contain a liquid crystal compound having a tolan structure. Even if the polymerizable liquid crystal composition used for the optically anisotropic layer of the present disclosure contains a liquid crystal compound having a tolan structure, the content of the liquid crystal compound should be within a range that does not adversely affect light resistance in an air atmosphere, and the content of the liquid crystal compound should be 5% by mass or less, and preferably 0% by mass, based on the total amount of the liquid crystal compound.

[0033] In the present disclosure, one period P of the liquid crystal alignment pattern may be 2 μm or less, or may be 1 μm or less.

[0034] The components included in the optical element of the present disclosure will be described in detail below. 1. Optically anisotropic layer The optically anisotropic layer included in the optical element of the present disclosure is a cured film of a polymerizable liquid crystal composition that contains a polymerizable liquid crystal compound (A) represented by the following general formula (1) and may further contain a polymerizable liquid crystal compound (B) represented by the following general formula (2):

[0035] 1-1. Polymerizable liquid crystal composition The polymerizable liquid crystal composition used for forming the optically anisotropic layer of the present disclosure contains a polymerizable liquid crystal compound (A) represented by the following general formula (1): The polymerizable liquid crystal composition may further contain a polymerizable liquid crystal compound (B) represented by the following general formula (2).

[0036] [ka] (In the general formulas (1) and (2), Z 1 , Z 2 , Z 3 , and Z 4each independently represents a hydrogen atom, -CN, -NCS, an alkoxy group having 1 to 10 carbon atoms, or a polymerizable group, and Z 1 and Z 2 at least one of represents a polymerizable group; 3 and Z 4 At least one of these represents a polymerizable group. R sp1 , R sp2 , R sp3 , and R sp4 each independently represent an alkylene group having 1 to 20 carbon atoms in which one -CH2- or two or more non-adjacent -CH2- groups may each independently be replaced by -O-, -COO-, -OCO-, -OCO-O-, -CO-NH-, -NH-CO-, or -CH=CH-, or a single bond. L 1 , L 2 , L 3 , L 4 , L 5 , L 6 , L 7 , and L 8 each independently represents -O-, -S-, -OCH2-, -CHO-, -CH2CH2-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -OCO-NH-, -NH-COO-, -NH-CO-NH-, -NH-O-, -O-NH-, -SCH2-, -CH2S-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -COO-CH2CH2-, -OCO-CH2CH2-, -CH2CH2-COO-, -CH2CH2-OCO-, -COO-CH2-, -OCO-CH2-, -CH2-COO-, -CH2-OCO-, -CH=CH-, or a single bond. Substituent E each independently represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylamino group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkanoyl group having 1 to 10 carbon atoms, an alkanoyloxy group having 1 to 10 carbon atoms, an alkanoylamino group having 1 to 10 carbon atoms, an alkanoylthio group having 1 to 10 carbon atoms, an alkyloxycarbonyl group having 2 to 10 carbon atoms, an alkylaminocarbonyl group having 2 to 10 carbon atoms, an alkylthiocarbonyl group having 2 to 10 carbon atoms, a hydroxy group, an amino group, a mercapto group, a carboxy group, a sulfo group, an amido group, a cyano group, a nitro group, a halogen atom, or a polymerizable group. However, when the above groups described as substituent E have -CH2-, substituent E also includes groups in which at least one of the -CH2-s in the above groups is replaced with -O-, -CO-, or -CH=CH-. Furthermore, when the above group described as the substituent E has a hydrogen atom, the substituent E also includes a group in which at least one of the hydrogen atoms contained in the above group is replaced with at least one selected from the group consisting of a fluorine atom and a polymerizable group. k1, k2, k3, and k4 each independently represent an integer of 0 to 4. n represents 1 or 2, m represents 1 or 3, and n' represents 0 or 1, and n×2+m+n'×2=5 is satisfied. L 2 , L 3 , and L 6 When there are a plurality of each of the groups, they may be the same or different, and when there are a plurality of each of the groups, they may be the same or different.

[0037] <Polymerizable Liquid Crystal Compound (A) and Polymerizable Liquid Crystal Compound (B)> Each symbol in the general formulas (1) and (2) will be explained in detail below. Z 1 , Z 2 , Z 3 , and Z 4 each independently represents a hydrogen atom, -CN, -NCS, an alkoxy group having 1 to 10 carbon atoms, or a polymerizable group, and Z 1 and Z 2at least one of represents a polymerizable group; 3 and Z 4 At least one of these represents a polymerizable group. Examples of the alkoxy group having 1 to 10 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentoxy group, etc. The alkoxy group having 1 to 10 carbon atoms may be an alkoxy group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms.

[0038] In order to make the optically anisotropic layer into a cured film of the polymerizable liquid crystal composition, Z 1 and Z 2 at least one of represents a polymerizable group; 3 and Z 4 At least one of Z represents a polymerizable group. 1 and Z 2 at least one of represents a polymerizable group; 3 and Z 4 When at least one of the groups represents a polymerizable group, the alignment state of the polymerizable liquid crystal compound (A) and the polymerizable liquid crystal compound (B) can be fixed, and the durability of the optically anisotropic layer can be improved. When the optically anisotropic layer is formed into a cured film of the polymerizable liquid crystal composition, the curability becomes more excellent, so Z 1 and Z 2 may both represent a polymerizable group, and Z 3 and Z 4 may both represent a polymerizable group. In terms of solubility, Z 1 and Z 2 One of the groups may be a polymerizable group, and the other may be an alkoxy group having 1 to 10 carbon atoms or a -CN (cyano group).

[0039] As the polymerizable group, any group used in a conventional polymerizable compound can be used without any limitation. The polymerizable groups preferably each independently represent a group selected from the following formulas (Z-1) to (Z-12): In the following formulas (Z-1) to (Z-12), * (asterisk) represents R sp1 , R sp2 , R sp3 , or R sp4The bond position is shown.

[0040] [ka] (In formulas (Z-1) to (Z-12), R z are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a methyl group, an ethyl group, or a trifluoromethyl group.

[0041] When using ultraviolet polymerization as the polymerization method, Z 1 is preferably the formula (Z-1), the formula (Z-2), the formula (Z-4), the formula (Z-6), or the formula (Z-9), more preferably the formula (Z-1), the formula (Z-4), or the formula (Z-9), and further preferably the formula (Z-1). In the formula (Z-1), R z It is particularly preferred that is a hydrogen atom, a methyl group or a trifluoromethyl group.

[0042] R sp1 , R sp2 , R sp3 , and R sp4 each independently represent an alkylene group having 1 to 20 carbon atoms in which one -CH2- or two or more non-adjacent -CH2- groups may each independently be replaced by -O-, -COO-, -OCO-, -OCO-O-, -CO-NH-, -NH-CO-, or -CH=CH-, or a single bond.

[0043] R sp1 , R sp2 , R sp3 , and R sp4From the viewpoint of availability of raw materials and ease of synthesis, it is more preferable that each independently represent an alkylene group having 1 to 12 carbon atoms, in which one -CH2- or two or more non-adjacent -CH2- groups may each independently be replaced by O-, -COO-, or -OCO-, or a single bond, it is even more preferable that each independently represent an alkylene group having 1 to 12 carbon atoms or a single bond, it is even more preferable that each independently represent an alkylene group having 1 to 10 carbon atoms or a single bond, and it is particularly preferable that each independently represent an alkylene group having 1 to 6 carbon atoms or a single bond, and when there are multiple groups, they may be the same or different.

[0044] Z 1 , Z 2 , Z 3 , and Z 4 are each independently a hydrogen atom, -CN, -NCS, or an alkoxy group having 1 to 10 carbon atoms, when the adjacent R sp1 , R sp2 , R sp3 , and R sp4 is preferably a single bond, and Z 1 , Z 2 , Z 3 , and Z 4 each independently represents a polymerizable group, the adjacent R sp1 , R sp2 , R sp3 , and R sp4 is preferably the alkylene group.

[0045] L 1 , L 2 , L 3 , L 4 , L 5 , L 6 , L 7 , and L 8each independently represents -O-, -S-, -OCH2-, -CHO-, -CH2CH2-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -OCO-NH-, -NH-COO-, -NH-CO-NH-, -NH-O-, -O-NH-, -SCH2-, -CH2S-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -COO-CH2CH2-, -OCO-CH2CH2-, -CH2CH2-COO-, -CH2CH2-OCO-, -COO-CH2-, -OCO-CH2-, -CH2-COO-, -CH2-OCO-, -CH=CH-, or a single bond. Also, L 2 , and L 3 When there are a plurality of each of these, they may be the same or different.

[0046] L 1 , L 2 , L 3 , L 4 , L 5 , L 6 , L 7 , and L 8More specifically, in terms of liquid crystal properties, ease of availability of raw materials, and ease of synthesis, -O-, -S-, -OCH2-, -CHO-, -CH2CH2-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -SCH2-, -CH2S-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -COO-CH2CH2-, -OCO-CH2CH2-, -CH2CH2-COO-, -CH2CH2-OCO-, -COO-CH2-, -OCO- It preferably represents CH2-, -CH2-COO-, -CH2-OCO-, -CH=CH- or a single bond, and more preferably represents -O-, -S-, -OCH2-, -CHO-, -CH2CH2-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -SCH2-, -CH2S-, -COO-CH2CH2-, -OCO-CH2CH2-, -CH2CH2-COO-, -CH2CH2-OCO-, -COO-CH2-, -OCO-CH2-, -CH2-COO-, -CH2-OCO- or a single bond.

[0047] L 1 , L 4 , L 5 , and L 8 preferably each independently represent -O-, -S-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, or a single bond, and more preferably represent -O-, -S-, -COO-, -OCO-, -O-CO-O-, or a single bond, from the viewpoints of solubility and orientation. L 2 , L 3 , L 6 , and L 7 preferably each independently represent -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -COO-CHCH-, -OCO-CHCH-, -CHCH-COO-, -CHCH-OCO-, or a single bond, from the standpoints of solubility and orientation. R sp1 , R sp2 , R sp3 , or R sp4When represents a single bond, the adjacent L 1 , L 4 , L 5 , and L 8 may be a single bond.

[0048] Substituent E each independently represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylamino group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkanoyl group having 1 to 10 carbon atoms, an alkanoyloxy group having 1 to 10 carbon atoms, an alkanoylamino group having 1 to 10 carbon atoms, an alkanoylthio group having 1 to 10 carbon atoms, an alkyloxycarbonyl group having 2 to 10 carbon atoms, an alkylaminocarbonyl group having 2 to 10 carbon atoms, an alkylthiocarbonyl group having 2 to 10 carbon atoms, a hydroxy group, an amino group, a mercapto group, a carboxy group, a sulfo group, an amido group, a cyano group, a nitro group, a halogen atom, or a polymerizable group. However, when the above groups described as substituent E have -CH2-, substituent E also includes groups in which at least one of the -CH2-s in the above groups is replaced with -O-, -CO-, or -CH=CH-. In addition, when the above group described as the substituent E has a hydrogen atom, a group in which at least one of the hydrogen atoms contained in the above group is replaced with at least one selected from the group consisting of a fluorine atom and a polymerizable group is also included in the substituent E. The polymerizable group here is the same as the above Z 1 and Z 2 The polymerizable group may be the same as that described above. The number of carbon atoms in the substituent E includes, for example, the number of carbon atoms in the carbonyl (C═O) in an alkanoyl group or an alkyloxycarbonyl group.

[0049] From the viewpoint of solubility, the substituent E may be an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkanoyl group having 1 to 10 carbon atoms, an alkanoyloxy group having 1 to 10 carbon atoms, an alkyloxycarbonyl group having 2 to 10 carbon atoms, a trifluoromethyl group, a hydroxy group, a carboxy group, a cyano group, a nitro group, or a halogen atom, or may be an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkanoyl group having 2 to 10 carbon atoms, an alkanoyloxy group having 2 to 10 carbon atoms, an alkyloxycarbonyl group having 2 to 10 carbon atoms, a trifluoromethyl group, or a halogen atom. From the viewpoints of solubility and ease of material availability, the substituent E is preferably an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkanoyl group having 2 to 6 carbon atoms, an alkanoyloxy group having 2 to 6 carbon atoms, an alkyloxycarbonyl group having 2 to 6 carbon atoms, a trifluoromethyl group, a fluorine atom, or a chlorine atom; more preferably an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkanoyl group having 2 to 5 carbon atoms, an alkanoyloxy group having 2 to 5 carbon atoms, an alkyloxycarbonyl group having 2 to 5 carbon atoms, a trifluoromethyl group, a fluorine atom, or a chlorine atom; and even more preferably a methyl group, ethyl group, n-propyl group, i-propyl group, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, methoxycarbonyl group, ethoxycarbonyl group, trifluoromethyl group, a fluorine atom, or a chlorine atom.

[0050] k1, k2, k3, and k4 each independently represent an integer of 0 to 4 and represent the number of substituents E substituted therewith. k1, k2, k3, and k4 may each independently be an integer of 0 to 3, an integer of 0 to 2, or 0 or 1.

[0051] In general formula (1), from the viewpoints of solubility, availability of raw materials, and ease of synthesis, it is preferable that k1 is 1 and the substituent E is a methyl group, ethyl group, n-propyl group, i-propyl group, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, methoxycarbonyl group, ethoxycarbonyl group, trifluoromethyl group, fluorine atom, or chlorine atom; it is more preferable that k1 is 1 and the substituent E is a methyl group, ethyl group, n-propyl group, i-propyl group, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, methoxycarbonyl group, ethoxycarbonyl group, fluorine atom, or chlorine atom; and it is even more preferable that k1 is 1 and the substituent E is a methyl group, methoxycarbonyl group, or ethoxycarbonyl group. In general formula (1), from the viewpoints of solubility, orientation, availability of raw materials, and ease of synthesis, m may be 1 or 3, at least one k1 may be 1, and the substituent E may be a methyl group, a methoxycarbonyl group, or an ethoxycarbonyl group.

[0052] In general formula (1), n represents 1 or 2, m represents 1 or 3, and n' represents 0 or 1, and n×2+m+n'×2=5 is satisfied. In general formula (1), n represents 1, m represents 1, and n' represents 1, and the general formula (1-1) below is preferred from the viewpoints of solubility and high refractive index anisotropy.

[0053] [ka] (In general formula (1-1), Z 1 , Z 2 , R sp1 , R sp2 , L 1 , L 2 , L 3 , L 4 , E, and k1 are as defined in general formula (1).

[0054] In the general formula (1-1), from the viewpoint of solubility and orientation, L 1 and L 4It is preferred that at least one of is -O-CO-O-, -COO-, -OCO-, -O-, or -S-; 1 and L 4 may be -O-CO-O-, -COO-, -OCO-, -O-, or -S-. In addition, in the general formula (1-1), from the viewpoint of solubility and orientation, L 2 and L 3 It is preferable that at least one of is -COO-CH2CH2-, -OCO-CH2CH2-, -CH2CH2-COO-, or -CH2CH2-OCO-, and L 2 and L 3 may be -COO-CH2CH2-, -OCO-CH2CH2-, -CH2CH2-COO-, or -CH2CH2-OCO-.

[0055] Examples of the polymerizable liquid crystal compound (A) represented by general formula (1) include, but are not limited to, the polymerizable liquid crystal compounds represented by the following (A-1) to (A-14).

[0056] [ka]

[0057] [ka]

[0058] [ka]

[0059] The polymerizable liquid crystal compound (A) represented by the general formula (1) may be a commercially available product, or may be synthesized by a conventionally known method. The polymerizable liquid crystal compound (A) represented by the general formula (1) can be synthesized by appropriately referring to JP-A-2008-544954 and the like. Specific examples of synthesis of the polymerizable liquid crystal compound (A) represented by general formula (1) will be shown in the examples below. Each intermediate used in the production may be a commercially available product or may be synthesized by a conventional method.

[0060] In general formula (2), from the viewpoint of solubility, it is preferable that at least one of k2, k3, and k4 is 1, and the substituent E is a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, a methoxycarbonyl group, an ethoxycarbonyl group, a trifluoromethyl group, a fluorine atom, or a chlorine atom; it is more preferable that k2 is 0, k3 is 1, and k4 is 0, and the substituent E is a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, a methoxycarbonyl group, an ethoxycarbonyl group, a fluorine atom, or a chlorine atom; and it is even more preferable that the substituent E is a methyl group, a methoxycarbonyl group, or an ethoxycarbonyl group.

[0061] In the general formula (2), from the viewpoint of solubility, L 5 and L 8 is preferably -O-CO-O-, -O-, or -S-.

[0062] Examples of the polymerizable liquid crystal compound (B) represented by general formula (2) include, but are not limited to, the polymerizable liquid crystal compounds represented by the following (B-1) to (B-8).

[0063] [ka]

[0064] [ka]

[0065] The polymerizable liquid crystal compound (B) represented by the general formula (2) may be a commercially available product, or may be synthesized by a conventionally known method. The polymerizable liquid crystal compound (B) represented by the general formula (2) can be synthesized by appropriately referring to Japanese Patent No. 6705548 and the like.

[0066] The phase transition temperatures of the polymerizable liquid crystal compound (A) represented by the general formula (1) and the polymerizable liquid crystal compound (B) represented by the general formula (2) may be independently 25°C or higher and 200°C or lower, more preferably 30°C or higher and 180°C or lower, and even more preferably 30°C or higher and 150°C or lower, from the viewpoints of expanding the options for usable substrates, improving industrial productivity, and reducing the load on the liquid crystal alignment process. In this specification, the phase transition temperature is measured using a differential scanning calorimeter (DSC).

[0067] Furthermore, the polymerizable liquid crystal compound (A) represented by the general formula (1) and the polymerizable liquid crystal compound (B) represented by the general formula (2) are each preferably soluble in at least one solvent selected from the group consisting of methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone at a concentration of 10% by mass or more, and more preferably soluble in at least 20% by mass, in order to broaden the range of substrates that can be used.

[0068] The content of the polymerizable liquid crystal compound (A) represented by the general formula (1) in the polymerizable liquid crystal composition used in the present disclosure is not particularly limited, and may be 10% by mass or more, 20% by mass or more, or 30% by mass or more, relative to the total mass of the solid content in the composition, or may be 98% by mass or less, 90% by mass or less, or 80% by mass or less. The polymerizable liquid crystal composition used in the present disclosure may use one type of polymerizable liquid crystal compound (A) alone or two or more types. When two or more types are used, the total content thereof is preferably within the above range. The solid content refers to all components in the composition other than the solvent. Components other than the solvent are considered to be solids even if they are liquid in nature.

[0069] The content of the polymerizable liquid crystal compound (B) represented by the general formula (2) in the polymerizable liquid crystal composition used in the present disclosure is not particularly limited, and may be 0 mass% or more, 10 mass% or more, or 20 mass% or more, or may be 98 mass% or less, 80 mass% or less, or 70 mass% or less, relative to the total mass of the solid content in the composition. The polymerizable liquid crystal composition used in the present disclosure may use one type of polymerizable liquid crystal compound (B) alone or two or more types. When two or more types are used, the total content thereof is preferably within the above range.

[0070] The content of the polymerizable liquid crystal compound (A) represented by the general formula (1) in the polymerizable liquid crystal composition used in the present disclosure may be 10% by mass or more, 20% by mass or more, or 40% by mass or more, or may be 100% by mass or less, 80% by mass or less, or 60% by mass or less, relative to the total mass of the polymerizable liquid crystal compound (A) represented by the general formula (1) and the polymerizable liquid crystal compound (B) represented by the general formula (2). It is preferable from the viewpoint of light resistance that the polymerizable liquid crystal composition used in the present disclosure contains a polymerizable liquid crystal compound (B) represented by the general formula (2) in addition to the polymerizable liquid crystal compound (A) represented by the general formula (1).

[0071] The total mass of the polymerizable liquid crystal compound (A) represented by the general formula (1) and the polymerizable liquid crystal compound (B) represented by the general formula (2) relative to the total mass of the liquid crystal compounds in the polymerizable liquid crystal composition used in the present disclosure may be 70 mass% or more, 80 mass% or more, 90 mass% or more, or even 100 mass%.

[0072] The polymerizable liquid crystal composition used in the present disclosure may contain other components in addition to the polymerizable liquid crystal compound (A) represented by the general formula (1) and the polymerizable liquid crystal compound (B) represented by the general formula (2). The other components will be described below.

[0073] <Other liquid crystal compounds> The polymerizable liquid crystal composition used in the present disclosure may contain a liquid crystal compound (also referred to as "other liquid crystal compound") different from the polymerizable liquid crystal compound (A) represented by the general formula (1) and the polymerizable liquid crystal compound (B) represented by the general formula (2). The other liquid crystal compound is preferably a rod-shaped liquid crystal compound, and is preferably a liquid crystal compound having a polymerizable group (other polymerizable liquid crystal compound).

[0074] Examples of rod-shaped liquid crystal compounds that are other liquid crystal compounds include rod-shaped nematic liquid crystal compounds. As the rod-shaped nematic liquid crystal compounds, azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, or alkenylcyclohexylbenzonitriles are preferred. As the other liquid crystal compounds, not only low-molecular-weight liquid crystal compounds but also polymeric liquid crystal compounds can be used, but low-molecular-weight liquid crystal compounds are preferred.

[0075] A liquid crystal compound having a polymerizable group can be obtained by introducing a polymerizable group into a liquid crystal compound. Examples of the polymerizable group include Z in the general formula (1). 1 and Z 2 Examples of the polymerizable groups include those exemplified in The number of polymerizable groups contained in the liquid crystal compound having a polymerizable group is preferably 1 to 6, more preferably 1 to 3, and may be 1 or 2.

[0076] The other liquid crystal compounds preferably have a high refractive index anisotropy Δn, specifically, 0.15 or more is preferable, 0.18 or more is more preferable, and 0.20 or more is even more preferable. There is no particular upper limit, but it is often 0.60 or less. Furthermore, by using a mixture of the polymerizable liquid crystal compound (A) represented by the general formula (1) and the polymerizable liquid crystal compound (B) represented by the general formula (2) with other liquid crystal compounds, for example, the crystallization temperature as a whole can be significantly reduced.

[0077] Examples of other liquid crystal compounds include those described in U.S. Pat. No. 4,683,327, U.S. Pat. No. 4,983,479, U.S. Pat. No. 5,622,648, U.S. Pat. No. 5,770,107, JP-T-11-513019, JP-T-2001-505879, JP-T-2001-527570, JP-A-1-272551, JP-A-6-16616, JP-A-7-110469, JP-A-11-80081, and JP-A-2001-328973, JP-A-2018-077465, and the like, and can be appropriately selected and used.

[0078] When the polymerizable liquid crystal composition used in the present disclosure contains other liquid crystal compounds, the content of the other liquid crystal compounds in the composition is not particularly limited, and may be 30% by mass or less, 20% by mass or less, 10% by mass or less, 5% by mass or less, or 0% by mass, relative to the total mass of the solid content in the composition. The polymerizable liquid crystal composition used in the present disclosure may contain one or more other liquid crystal compounds. When two or more compounds are used, the total content thereof is preferably within the above range.

[0079] <Polymerization initiator> The polymerizable liquid crystal composition used in the present disclosure preferably contains a polymerization initiator. The polymerization initiator is preferably a photopolymerization initiator capable of initiating a polymerization reaction upon irradiation with ultraviolet light. In this embodiment, the photopolymerization initiator can be appropriately selected from conventionally known photopolymerization initiators. Specific examples of such photopolymerization initiators include aromatic ketones, such as thioxanthone, α-aminoalkylphenones, α-hydroxyketones, acylphosphine oxides, oxime esters, aromatic onium salts, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamine compounds. Among these, at least one selected from the group consisting of acylphosphine oxide-based polymerization initiators, α-aminoalkylphenone-based polymerization initiators, α-hydroxyketone-based polymerization initiators, and oxime ester-based polymerization initiators is preferred, as it hardens the coating film to its interior and improves durability.

[0080] Examples of the acylphosphine oxide polymerization initiator include bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide (e.g., trade name: Omnirad819, manufactured by IGM RESINS BV), bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphenylphosphine oxide, and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (trade name: Omnirad TPO H, manufactured by IGM RESINS BV).

[0081] Furthermore, examples of the α-aminoalkylphenone polymerization initiator include 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (e.g., Omnirad907, manufactured by IGM RESINS BV), 2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone (e.g., Omnirad369, manufactured by IGM RESINS BV), and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (Omnirad379EG, manufactured by IGM RESINS BV).

[0082] Examples of the α-hydroxyketone polymerization initiator include 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one (for example, trade name: Omnirad127, manufactured by IGM RESINS BV), 2-hydroxy-4'-hydroxyethoxy-2-methylpropiophenone (for example, trade name: Omnirad2959, manufactured by IGM RESINS BV), 1-hydroxy-cyclohexyl-phenyl-ketone (for example, trade name: Omnirad184, manufactured by IGM RESINS BV), and oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone} (for example, trade name: ESACURE ONE, manufactured by IGM RESINS BV).

[0083] Examples of the oxime ester polymerization initiator include 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)] (trade name: Irgacure OXE-01, manufactured by BASF), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) (trade name: Irgacure OXE-02, manufactured by BASF), and methanone, ethanone, 1-[9-ethyl-6-(1,3-dioxolane, 4-(2-methoxyphenoxy)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) (trade name ADEKA OPT-N-1919, manufactured by ADEKA Corporation).

[0084] When the polymerizable liquid crystal composition used in the present disclosure contains a polymerization initiator, the content of the polymerization initiator in the composition is not particularly limited, and may be 0.1% by mass or more, or 1% by mass or more, or may be 20% by mass or less, or 10% by mass or less, or 8% by mass or less, relative to the total mass of the liquid crystal compounds in the polymerizable liquid crystal composition (when the composition contains other liquid crystal compounds, relative to the total mass of the polymerizable liquid crystal compound (A) represented by general formula (1), the polymerizable liquid crystal compound (B) represented by general formula (2), and the other liquid crystal compounds). The polymerizable liquid crystal composition used in the present disclosure may use one type of polymerization initiator alone or two or more types. When two or more types are used, the total content thereof is preferably within the above range.

[0085] <Chiral Agents> The polymerizable liquid crystal composition used in the present disclosure may contain a chiral agent. When the polymerizable liquid crystal composition used in the present disclosure contains a chiral agent, it can form a cholesteric phase. The type of chiral agent is not particularly limited. The chiral agent may be liquid crystalline or non-liquid crystalline. The chiral agent generally contains an asymmetric carbon atom. However, axially asymmetric compounds or planar asymmetric compounds that do not contain an asymmetric carbon atom can also be used as the chiral agent. Examples of axially asymmetric compounds or planar asymmetric compounds include binaphthyl, helicene, paracyclophane, and derivatives thereof. The chiral agent may have a polymerizable group. Specific examples of the chiral agent include those described in JP-A-08-245960, EP1816180, Japanese Patent No. 5284735, and Japanese Patent No. 4871139.

[0086] When the polymerizable liquid crystal composition used in the present disclosure contains a chiral dopant, the content of the chiral dopant in the composition is not particularly limited, and may be 0.01% by mass or more, or 0.1% by mass or more, relative to the total mass of the liquid crystal compounds in the polymerizable liquid crystal composition (when the composition contains other liquid crystal compounds, relative to the total mass of the polymerizable liquid crystal compound (A) represented by general formula (1), the polymerizable liquid crystal compound (B) represented by general formula (2), and the other liquid crystal compounds), or may be 30% by mass or less, or 20% by mass or less, or 10% by mass or less. The polymerizable liquid crystal composition used in the present disclosure may use one chiral dopant alone or two or more chiral dopants. When two or more chiral dopants are used, the total content thereof is preferably within the above range.

[0087] <Solvent> The polymerizable liquid crystal composition used in the present disclosure may contain a solvent, if necessary, from the viewpoint of coatability. The solvent may be appropriately selected from conventionally known solvents capable of dissolving or dispersing each component contained in the polymerizable liquid crystal composition. Specific examples include hydrocarbon solvents such as hexane, cyclohexane, and toluene; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone; ether solvents such as tetrahydrofuran, 1,3-dioxolane, and propylene glycol monoethyl ether (PGME); alkyl halide solvents such as chloroform and dichloromethane; ester solvents such as ethyl acetate and propylene glycol monomethyl ether acetate; amide solvents such as N,N-dimethylformamide and N-methylpyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; and alcohol solvents such as methanol, ethanol, and propanol. In this embodiment, the solvent may be used alone or in combination as a mixed solvent of two or more solvents. When the polymerizable liquid crystal composition used in the present disclosure contains a solvent, the content of the solvent in the composition is preferably an amount that makes the solid content concentration of the composition 0.5 to 30 mass %, more preferably an amount that makes 1 to 20 mass %. The polymerizable liquid crystal composition used in the present disclosure may use one solvent alone or two or more solvents. When two or more solvents are used, the total content thereof is preferably within the above range.

[0088] <Surfactant> The polymerizable liquid crystal composition used in the present disclosure may contain a surfactant that contributes to the stable or rapid formation of a liquid crystal phase (for example, a nematic phase, a cholesteric phase). Examples of surfactants include fluorine-containing (meth)acrylate polymers, compounds represented by general formulas (X1) to (X3) described in WO2011 / 162291, compounds represented by general formula (I) described in paragraphs 0082 to 0090 of JP-A No. 2014-119605, and compounds described in paragraphs 0020 to 0031 of JP-A No. 2013-47204. Examples of fluorine-containing (meth)acrylate polymers that can be used as surfactants include the polymers described in paragraphs 0018 to 0043 of JP-A No. 2007-272185.

[0089] When the polymerizable liquid crystal composition used in the present disclosure contains a surfactant, the content of the surfactant is not particularly limited, and may be 0.01% by mass or more, or 0.05% by mass or more, relative to the total mass of the liquid crystal compounds in the polymerizable liquid crystal composition (when the composition contains other liquid crystal compounds, relative to the total mass of the polymerizable liquid crystal compound (A) represented by general formula (1), the polymerizable liquid crystal compound (B) represented by general formula (2), and the other liquid crystal compounds), or may be 10% by mass or less, or 5% by mass or less, or 3% by mass or less. The polymerizable liquid crystal composition used in the present disclosure may contain one surfactant alone or two or more surfactants. When two or more surfactants are used, the total content thereof is preferably within the above range.

[0090] In addition to the above, the polymerizable liquid crystal composition used in the present disclosure may contain other components such as an antioxidant, an ultraviolet absorber, a sensitizer, a stabilizer, a plasticizer, a chain transfer agent, a polymerization inhibitor, an antifoaming agent, a leveling agent, a thickener, a flame retardant, a surfactant, a dispersant, and a coloring material such as a dye or a pigment.

[0091] 1-2. Method for forming optically anisotropic layer The optically anisotropic layer of the present disclosure is an optically anisotropic layer that is a cured film of the polymerizable liquid crystal composition. The method for curing the polymerizable liquid crystal composition used in the present disclosure is not particularly limited, and any known method can be used. For example, an embodiment may include a step of contacting the polymerizable liquid crystal composition with an alignment film provided on a support (described below) to form a composition layer on the alignment film provided on the support (composition layer forming step), a step of subjecting the composition layer to a heat treatment to align the liquid crystal compound in the polymerizable liquid crystal composition (alignment step), and then a step of subjecting the composition layer to a curing treatment (curing step). According to this embodiment, the liquid crystal compound in the polymerizable liquid crystal composition can be fixed in an aligned state, and an optically anisotropic layer can be formed.

[0092] The composition layer forming step is a step of bringing an alignment film provided on a support into contact with the polymerizable liquid crystal composition to form a composition layer on the alignment film provided on the support. The support and alignment film used will be described later. There are no particular limitations on the method for bringing the alignment film provided on the support into contact with the composition, and examples thereof include a method in which the composition is applied onto the support. The coating method may be appropriately selected as long as it can form a film with a desired thickness with high accuracy, and examples thereof include gravure coating, reverse coating, knife coating, dip coating, spray coating, air knife coating, spin coating, roll coating, printing, immersion and pulling up, curtain coating, die coating, casting, bar coating, extrusion coating, and E-type coating.

[0093] The alignment step is a step of subjecting the composition layer to a heat treatment to align the liquid crystal compound in the polymerizable liquid crystal composition. The composition layer is heated at a temperature at which the polymerizable liquid crystal compound (A) represented by general formula (1), the polymerizable liquid crystal compound (B) represented by general formula (2) that is added as needed, and other liquid crystal compounds can be aligned. By this heat treatment, the polymerizable liquid crystal compound (A) represented by general formula (1), the polymerizable liquid crystal compound (B) represented by general formula (2) that is added as needed, and other liquid crystal compounds can be aligned and dried, and can be fixed while maintaining the aligned state. The temperature at which orientation can be achieved varies depending on the substances in the composition and must be adjusted appropriately. For example, it is preferably performed within a range of 40°C or higher and 200°C or lower, and more preferably within a range of 60°C or higher and 150°C or lower. As the heating means, known heating and drying means can be appropriately selected and used. The heating time may be selected appropriately, for example, within the range of 10 seconds to 2 hours, preferably 20 seconds to 30 minutes.

[0094] By subjecting the composition layer to a heat treatment, the liquid crystal compound in the polymerizable liquid crystal composition is aligned, forming a liquid crystal phase. For example, when the composition layer contains a chiral agent, a cholesteric liquid crystal phase is formed.

[0095] After the orientation step, a curing step is carried out. The method of curing treatment is not particularly limited, and examples thereof include photocuring treatment and heat curing treatment. Among these, photoirradiation treatment is preferred, and ultraviolet irradiation treatment is more preferred. As the light irradiation, ultraviolet irradiation is preferably used. For ultraviolet irradiation, ultraviolet rays emitted from light rays of an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp, etc. can be used. The irradiation amount of the energy ray source may be appropriately selected, and the cumulative exposure amount at an ultraviolet wavelength of 365 nm is, for example, 10 mJ / cm. 2 More than 10000mJ / cm 2 It is preferable that the content is within the following range.

[0096] The cured product obtained by the above treatment corresponds to a layer in which a liquid crystal phase is fixed. For example, when the polymerizable liquid crystal composition contains a chiral agent, a layer in which a cholesteric liquid crystal phase is fixed is formed. It should be noted that these layers no longer need to exhibit liquid crystallinity. More specifically, for example, the state in which the cholesteric liquid crystal phase is "fixed" is the most typical and preferred state in which the orientation of the liquid crystal compound in the cholesteric liquid crystal phase is maintained. More specifically, it is preferred that the layer has no fluidity in the temperature range of usually 0 to 50°C, or under more severe conditions, -30 to 70°C, and that the fixed orientation can be stably maintained without causing any change in the orientation due to an external field or external force.

[0097] The thickness of the optically anisotropic layer is not particularly limited and may be appropriately selected depending on the application. The thickness of the optically anisotropic layer may be 1.00 μm or more, and the upper limit may be 10.00 μm or less, or 5.00 μm or less, from the viewpoints of ease of coating, productivity, and substrate warpage.

[0098] From the viewpoint of light resistance, the optically anisotropic layer preferably has a maximum wavelength of 350 nm or less, and may have a maximum wavelength of 340 nm or less, among wavelengths at which the absorbance per 1.00 μm of layer thickness is 1.0 in the absorption spectrum of wavelengths from 200 nm to 500 nm. When the wavelength at which the absorbance on the long wavelength side becomes 1.0 falls within this range, it is believed that the optically anisotropic layer is less likely to absorb ultraviolet light from outside, photodegradation is more likely to be suppressed, and light resistance is improved. The absorption spectrum of the optically anisotropic layer is obtained by measuring the absorbance at 1.0 nm intervals over the range of 200 nm to 800 nm using an ultraviolet-visible spectrophotometer (Shimadzu Corporation, UV-2700). The absorbance of the optically anisotropic layer obtained is divided by the layer thickness (μm) to two decimal places to determine the absorbance per 1.00 μm of layer thickness.

[0099] Furthermore, in order to suppress alignment defects, the optically anisotropic layer preferably has an absorption maximum wavelength on the long wavelength side in the absorption spectrum of 200 nm to 500 nm, of 270 nm or more and 320 nm or less, with the lower limit being 280 nm or more and the upper limit being 310 nm or less. When the absorption maximum wavelength on the long wavelength side is within this range, it is believed that the heat absorbed by ultraviolet irradiation during formation of the optically anisotropic layer is reduced, making it easier to suppress alignment defects. Furthermore, generally, shortening the absorption maximum wavelength on the long wavelength side reduces deterioration of optical properties due to light and improves light resistance. When the optically anisotropic layer contains the polymerizable liquid crystal compound (A) represented by the general formula (1) and the polymerizable liquid crystal compound (B) represented by the general formula (2), it is preferable that the absorption maximum wavelength of the polymerizable liquid crystal compound (B) is on the shorter wavelength side than the absorption maximum wavelength of the polymerizable liquid crystal compound (A) in the absorption spectrum at a wavelength of 200 nm to 500 nm. To clearly distinguish the maximum absorption wavelength on the long wavelength side in the absorption spectrum of the optically anisotropic layer, the absorption spectrum of each liquid crystal compound contained in the optically anisotropic layer was measured. A 0.01 g / L solution of each liquid crystal compound (solvent: 1,3-dioxolane) was placed in a 1 cm quartz cell, and the absorbance was measured at 1.0 nm intervals in the range of 200 nm to 800 nm using a UV-visible spectrophotometer (Shimadzu Corporation, UV-2700). In the obtained absorption spectrum, peaks with an absorbance of 0.3 or more were detected, and the maximum absorption wavelength on the long wavelength side was determined.

[0100] In terms of solubility and orientation, the optically anisotropic layer may have a refractive index anisotropy Δn of 0.16 to 0.24, or may be 0.17 or more and 0.23 or less, measured with light having a wavelength of 550 nm. The refractive index anisotropy Δn measured with light of a wavelength of 550 nm was calculated from the in-plane retardation value (Re(550)) at a wavelength of 550 nm and the layer thickness d (nm) using the following formula: 550 Ask for. Δn 550 =Re(550) / layer thickness d(nm) The in-plane retardation value at a wavelength of 550 nm (Re(550)) and the layer thickness d (nm) are measured in the same manner as in the examples.

[0101] The presence of the polymerizable liquid crystal compound (A) represented by the specific general formula (1) or the polymerizable liquid crystal compound (B) represented by the general formula (2) in the optically anisotropic layer can be confirmed by collecting and analyzing a material from the optically anisotropic layer. NMR, IR, GC-MS, XPS, TOF-SIMS, or a combination thereof can be used as the analytical method.

[0102] 2.Support The support 1 supports the alignment film 5 and the optically anisotropic layer 10 .

[0103] The support 1 can be any sheet-like material (film, plate-like material) as long as it can support the alignment film and the optically anisotropic layer. The support 1 is preferably a transparent support, and examples thereof include polyacrylic resin films such as polymethyl methacrylate, cellulose resin films such as cellulose triacetate, cycloolefin polymer films (for example, trade name "Arton" manufactured by JSR Corporation, trade name "Zeonor" manufactured by Zeon Corporation), polyethylene terephthalate (PET), polycarbonate, polyvinyl chloride, etc. The support is not limited to flexible films, and may be a non-flexible substrate such as a glass substrate.

[0104] There is no limitation on the thickness of the support 1, and it may be set appropriately depending on the application of the optical element 100, the material from which the support 1 is made, and so on, so that the thickness can support the alignment film and the optically anisotropic layer. The thickness of the support 1 may be 1 μm to 1000 μm, may be 3 μm to 250 μm, or may be 5 μm to 150 μm.

[0105] 3.Alignment film At least when the optically anisotropic layer 10 is formed, an alignment film 5 is provided on the surface of the support 1 . The alignment film 5 is an alignment film for aligning the polymerizable liquid crystal compound 20 into a predetermined liquid crystal alignment pattern when forming the optically anisotropic layer 10. As described above, in the optical element 100, the optically anisotropic layer 10 has a liquid crystal alignment pattern in which the direction of the optical axis 20A (see FIG. 2) derived from the polymerizable liquid crystal compound 20 changes while continuously rotating along one in-plane direction (x direction). Therefore, the alignment film is formed so that the optically anisotropic layer can form this liquid crystal alignment pattern.

[0106] As the alignment film, various known films can be used. Examples include rubbed films made of organic compounds such as polymers, obliquely evaporated films of inorganic compounds, films with microgrooves, and films formed by accumulating LB (Langmuir-Blodgett) films made of organic compounds such as ω-tricosanoic acid, dioctadecylmethylammonium chloride, and methyl stearate using the Langmuir-Blodgett method.

[0107] The alignment film can be formed by rubbing the surface of the polymer layer several times in a certain direction with paper or cloth. Preferred examples of materials used for the alignment film include polyimide, polyvinyl alcohol, polymers having polymerizable groups as described in JP-A-9-152509, and materials used to form alignment films as described in JP-A-2005-97377, JP-A-2005-99228, and JP-A-2005-128503.

[0108] The alignment film may also be a photo-alignment film formed by irradiating a photo-alignment material with polarized or unpolarized light. The polarized light can be irradiated from a direction perpendicular to or oblique to the photo-alignment film, and the unpolarized light can be irradiated from a direction oblique to the photo-alignment film.

[0109] The photo-alignment material used in the photo-alignment film can be appropriately selected from conventionally known photo-alignment materials. Examples of the photo-alignment material include those disclosed in JP 2006-285197 A, JP 2007-76839 A, JP 2007-138138 A, JP 2007-94071 A, JP 2007-121721 A, JP 2007-140465 A, JP 2007-156439 A, JP 2007-133184 A, and JP azo compounds described in Japanese Patent Nos. 2009-109831, 3883848 and 4151746, aromatic ester compounds described in Japanese Patent Laid-Open No. 2002-229039, maleimides and / or alkenyl compounds having photo-alignable units described in Japanese Patent Laid-Open Nos. 2002-265541 and 2002-317013, Preferred examples include alkyl-substituted nadimide compounds, photocrosslinkable silane derivatives described in Japanese Patent Nos. 4205195 and 4205198, photocrosslinkable polyimides, photocrosslinkable polyamides, and photocrosslinkable esters described in JP-T-2003-520878, JP-T-2004-529220, and Japanese Patent No. 4162850, and photodimerizable compounds described in JP-A-9-118717, JP-A-10-506420, JP-A-2003-505561, WO 2010 / 150748, JP-A-2013-177561, and JP-A-2014-12823, in particular cinnamate compounds, chalcone compounds, and coumarin compounds. Among these, azo compounds, photocrosslinkable polyimides, photocrosslinkable polyamides, photocrosslinkable esters, cinnamate compounds, and chalcone compounds are preferably used.

[0110] There is no limitation on the method for forming the alignment film, and various known methods can be used depending on the material for forming the alignment film. For example, there is a method in which an alignment film is applied to the surface of the support 1, dried, and then exposed to laser light to form an alignment pattern. For a method and exposure apparatus for exposing an alignment film to form an alignment pattern, reference can be made to, for example, paragraphs 0078 to 0080 and Figure 5, paragraphs 0098 to 0107 and Figures 8 to 10 of International Publication No. 2020 / 022496, and paragraphs 0075 to 0076 and Figure 1 of JP-A-2015-532468.

[0111] The alignment film may also be a shaped resin layer having the uneven surface of the alignment pattern. For example, the support 1 is coated with an energy ray curable resin, and then a roll plate having an uneven surface is used to transfer the uneven surface to the energy ray curable resin on the support, and the energy ray curable resin is cured by irradiating it with energy rays. For a method of forming an alignment film of a shaped resin layer having an uneven surface, see, for example, paragraphs 0041 to 0043 and Figures 3 to 4 of JP 2022-147451 A. The uneven shape of the orientation pattern formed in the shaped resin layer may be, for example, a continuous arc shape, or a pattern obtained by dividing an arc and approximating it with straight lines.

[0112] There is no limitation on the thickness of the alignment film, and the thickness may be appropriately set to obtain the required alignment function depending on the material from which the alignment film is formed. When an alignment pattern is formed by exposure, the thickness of the alignment film is preferably 0.01 μm to 2 μm, more preferably 0.05 μm to 1 μm. When a shaped resin layer having an uneven surface is formed, the thickness of the alignment film is preferably 0.5 μm to 20 μm, more preferably 1 μm to 10 μm.

[0113] By forming an optically anisotropic layer on an alignment film having an alignment pattern in which the alignment state changes periodically, as described above, an optically anisotropic layer 10 can be formed having a liquid crystal alignment pattern in which the optical axis 20A derived from the polymerized liquid crystal compound 20 continuously rotates in one direction.

[0114] In the optical element of the present disclosure, the alignment film is provided as a preferred embodiment, but is not an essential component. For example, by forming an orientation pattern on the support 1 by a method such as rubbing the support 1 or processing the support 1 with laser light, it is possible to configure the optically anisotropic layer 10 to have a liquid crystal orientation pattern in which the direction of the optical axis 20A derived from the polymerizable liquid crystal compound 20 changes while continuously rotating along at least one direction in the plane.

[0115] 4. Other Aspects of Optical Elements FIG. 3 is a side view schematically showing an optical element 101 according to another embodiment of the present invention. The optical element 101 includes, as a first optically anisotropic layer, an optically anisotropic layer 11 in which a liquid crystal compound 20 is cholesterically aligned in the thickness direction. The optical element 101 shown in Fig. 3 may also have a configuration in which the optically anisotropic layer 11 is provided on an alignment film formed on a support.

[0116] Cholesteric liquid crystal phases are known to exhibit selective reflection at specific wavelengths. The central wavelength of selective reflection (selective reflection central wavelength) λ depends on the pitch Ps (= helical period) of the helical structure in the cholesteric liquid crystal phase, and follows the relationship λ = n × Ps with the average refractive index n of the cholesteric liquid crystal phase. Therefore, the selective reflection central wavelength can be adjusted by adjusting the pitch of this helical structure.

[0117] Cholesteric liquid crystal phases exhibit selective reflection for either left- or right-handed circularly polarized light at a specific wavelength. Whether the reflected light is right-handed or left-handed circularly polarized depends on the twist direction (sense) of the helix of the cholesteric liquid crystal phase. When the twist direction of the helix of the cholesteric liquid crystal phase is right-handed, right-handed circularly polarized light is reflected, and when the twist direction of the helix is left-handed, left-handed circularly polarized light is reflected.

[0118] Furthermore, the half-width Δλ (nm) of the selective reflection band (circularly polarized light reflection band) that exhibits selective reflection depends on the Δn of the cholesteric liquid crystal phase and the helical pitch Ps, and follows the relationship Δλ = Δn × Ps. Therefore, the width of the selective reflection band can be controlled by adjusting Δn.

[0119] That is, the optically anisotropic layer 11 has the function of selectively reflecting light of a specific circularly polarized light (right-handed or left-handed circularly polarized light) in a predetermined wavelength range.

[0120] On the other hand, the orientation pattern of the optical axis 20A in the in-plane direction of the optical element 101 is the same as the orientation pattern of the optical element 10 shown in Fig. 2, and therefore the optical element 101 exhibits the same effect as the optical element 100. That is, like the above-described optical element 100, the optical element 101 exhibits the effect of changing the absolute phase of incident light and bending the light in a predetermined direction. Therefore, the optical element 101 combines the effect of bending incident light in a direction different from the incident direction and the effect of the above-described cholesteric orientation, and reflects light at an angle in a predetermined direction with respect to the reflection direction of specular reflection.

[0121] For example, suppose that the cholesteric liquid crystal phase of the optically anisotropic layer 11 is designed to reflect right-handed circularly polarized light. In this case, as shown in FIG. 3, right-handed circularly polarized light P is reflected perpendicularly to the main surface of the optically anisotropic layer 11 of the optical element 101, i.e., along the normal line. R When light L1 having a value of θ is incident, reflected light L2 is generated in a direction tilted relative to the normal direction. In other words, the optical element 101 functions as a reflective diffraction grating.

[0122] In the optical element 101 having this configuration, the optically anisotropic layer of the present disclosure is a cured film of the polymerizable liquid crystal composition, so that alignment defects are suppressed and improved diffraction efficiency can be obtained.

[0123] In the optical element shown in FIGS. 1 to 3, the optical axis 20A of the polymerizable liquid crystal compound 20 in the liquid crystal alignment pattern of the optically anisotropic layer rotates continuously in-plane along only the x direction. However, the optical element of the present disclosure is not limited to this, and various configurations are available as long as the optical axis 20A of the polymerizable liquid crystal compound 20 in the optically anisotropic layer rotates continuously along one direction.

[0124] Fig. 4 is a plan view schematic diagram of the optically anisotropic layer 12 of the optical element of the modified design. In Fig. 4, the liquid crystal orientation pattern is represented by the optical axis 20A of the liquid crystal compound. The optically anisotropic layer 12 has a liquid crystal orientation pattern in which regions in which the direction of the optical axis 20A is the same are arranged concentrically, and one direction in which the direction of the optical axis 20A changes while continuously rotating is arranged radially from the center of the optically anisotropic layer 12. In the optically anisotropic layer 12, the direction of the optical axis 20A changes while continuously rotating along a number of directions extending from the center of the optically anisotropic layer 12 outward, such as the direction indicated by arrow 51, the direction indicated by arrow 52, etc. The absolute phase of circularly polarized light incident on the optically anisotropic layer 12 having this liquid crystal orientation pattern changes in each local region where the optical axis of the polymerizable liquid crystal compound 20 has a different orientation. At this time, the amount of change in each absolute phase differs depending on the orientation of the optical axis of the polymerizable liquid crystal compound 20 into which the circularly polarized light is incident.

[0125] The optically anisotropic layer 12 having such a concentric liquid crystal orientation pattern, i.e., a liquid crystal orientation pattern in which the optical axis changes by continuously rotating radially, can transmit incident light as divergent or convergent light depending on the rotation direction of the optical axis of the polymerizable liquid crystal compound 20 and the direction of the incident circularly polarized light. That is, by forming the liquid crystal alignment pattern of the optically anisotropic layer into a concentric circle, the optical element can function as, for example, a convex or concave lens.

[0126] Here, when the liquid crystal orientation pattern of the optically anisotropic layer is concentric and the optical element acts as a convex lens, it is preferable to gradually shorten the length of one period (pitch P) in which the optical axis rotates 180° in the liquid crystal orientation pattern from the center of the optically anisotropic layer 12 toward the outside in one direction in which the optical axis continuously rotates. As mentioned above, the angle of refraction of light relative to the incident direction increases as the length of one period in the liquid crystal orientation pattern decreases. Therefore, by gradually decreasing the length of one period in the liquid crystal orientation pattern from the center of the optically anisotropic layer 12 toward the outside in one direction in which the optical axis continuously rotates, the light focusing power of the optically anisotropic layer 12 can be further improved, thereby improving the performance as a convex lens.

[0127] Furthermore, depending on the application of the optical element, for example, when it is used as a concave lens, it is preferable to gradually shorten the length of one period in which the optical axis in the liquid crystal orientation pattern rotates by 180° from the center of the optically anisotropic layer 12, in a direction opposite to that in the case of a convex lens, and outward in one direction. As mentioned above, the angle of refraction of light relative to the incident direction increases as the length of one period in the liquid crystal orientation pattern decreases. Therefore, by gradually decreasing the length of one period in the liquid crystal orientation pattern from the center of the optically anisotropic layer 12 toward the outside in one direction in which the optical axis continuously rotates, the light divergence power of the optically anisotropic layer 12 can be further improved, thereby improving the performance as a concave lens.

[0128] It is also preferable to reverse the rotation direction of the incident circularly polarized light, for example, when the optical element is a concave lens.

[0129] Conversely, the length of one period in the concentric liquid crystal alignment pattern may be gradually increased from the center of the optically anisotropic layer 12 outward in one direction in which the optical axis continuously rotates. Furthermore, depending on the application of the optical element, for example when it is desired to provide a light intensity distribution to transmitted light, it is also possible to use a configuration in which, rather than gradually changing the length of one period in one direction in which the optical axis continuously rotates, there are regions in which the length of one period differs in parts in one direction in which the optical axis continuously rotates. In addition, the optical element of the present disclosure may have an optically anisotropic layer in which the length of one period is uniform across the entire surface, and an optically anisotropic layer having regions in which the length of one period varies.

[0130] In this way, the configuration in which the length of one period in which the optical axis rotates 180° is changed in one direction in which the optical axis continuously rotates can also be used in the configuration in which the optical axis 20A of the polymerizable liquid crystal compound 20 continuously rotates and changes only in one direction, the x direction, as shown in Figures 1 and 2. For example, by gradually shortening the length of one period of the liquid crystal orientation pattern in the x direction, an optical element that transmits light in a condensed manner can be obtained. Also, by reversing the direction in which the optical axis rotates 180° in the liquid crystal orientation pattern, an optical element that transmits light in a diffusive manner only in the x direction can be obtained. Furthermore, depending on the application of the optical element, for example when it is desired to provide a light intensity distribution to transmitted light, the length of one period may not be gradually changed in the x direction, but may instead have regions in the x direction where the length of one period is partially different.

[0131] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any embodiment that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits similar effects is included within the technical scope of the present disclosure. [Example]

[0132] The present disclosure will be described in more detail below with reference to examples and comparative examples. In this specification, various parameters are values measured at a temperature of 25°C ± 2°C and a relative humidity of 40% to 65%, unless otherwise specified. Furthermore, before starting each measurement, the target sample is exposed to the above atmosphere for 30 minutes or more before measurement and evaluation. Each compound was analyzed using a JEOL JNM-LA400WB analyzer manufactured by JEOL Ltd. 1 The chemical structure was confirmed by 1 H NMR measurement.

[0133] In addition, in this disclosure, the various parameters of (2) in-plane retardation Re and (5) diffraction efficiency in the following evaluation items refer to the average values of measurements taken at nine locations unless otherwise specified. The nine measurement locations are the nine intersections of lines drawn from the outer edge of the measurement sample to divide the inner region into four equal parts in the vertical and horizontal directions, and the measurement centers are the nine intersections. If the measurement sample is rectangular, measurements are taken with the nine intersections of the lines drawn from the outer edge of the rectangle to divide the inner region into four equal parts in the vertical and horizontal directions as the centers, and the average value is calculated. Note that if the measurement sample has a shape other than a rectangle, such as a circle, ellipse, triangle, or pentagon, a rectangle with the largest area inscribed in the shape is drawn, and measurements are taken at nine locations on the rectangle using the above method.

[0134] [Preparation of liquid crystal compounds] (Synthesis of polymerizable liquid crystal compound (A-1)) The polymerizable liquid crystal compound (A-1) was synthesized according to the following scheme.

[0135] [ka]

[0136] (1) Synthesis of Compound 1 Dimethylacetamide (DMAc) (600 mL) was added to 6-hydroxy-2-naphthoic acid (56.5 g, 300.0 mmol), 4-chlorobutyl acetate (13.5 g, 900.0 mmol), potassium carbonate (124.4 g, 900.0 mmol), and potassium iodide (5.0 g, 30.0 mmol). The resulting mixture was stirred at 80°C for 3 hours. A solution of sodium hydroxide (60.0 g, 1500.0 mmol) in 600 mL of water and 120 mL of methanol was added to the resulting mixture, and the mixture was stirred at 80°C for 3 hours. The resulting mixture was cooled to room temperature, the methanol was removed under reduced pressure, and 1 M hydrochloric acid (3000 mL) was added to the resulting residue. Water and ethyl acetate were added to the resulting mixture, followed by extraction with ethyl acetate. The solvent from the resulting organic layer was removed under reduced pressure. The obtained solid was purified by reslurrying in diisopropyl ether to obtain Compound 1 (73.6 g, 282.6 mmol) in a yield of 94.2%.

[0137] (2) Synthesis of Compound 2 Compound 1 (39.4 g, 150 mmol) and N,N-dimethylaniline (27.3 g, 225.0 mmol) were dissolved in tetrahydrofuran (THF) (450 mL). The resulting solution was cooled to 10°C, and acrylic acid chloride (20.4 g, 225.0 mmol) was added dropwise. The mixture was stirred at 10°C for 1 hour. Water and ethyl acetate were added to the resulting mixture, followed by extraction with ethyl acetate. The solvent in the resulting organic layer was evaporated under reduced pressure. The resulting residue was recrystallized using toluene to give compound 2 (46.6 g, 148.2 mmol). The yield was 98.8%.

[0138] (3) Synthesis of polymerizable liquid crystal compound (A-1) Compound 2 (23.6 g, 75.0 mmol), 2-(4-hydroxyphenyl)ethanol (4.1 g, 30.0 mmol), and 4-dimethylaminopyridine (DMAP) (0.37 g, 3.0 mmol) were dissolved in CHCl (30 mL). The resulting solution was cooled to 15°C, and N,N-diisopropylcarbodiimide (11.4 g, 90.0 mmol) was added dropwise. The mixture was stirred at 15°C for 3 hours. Methanol (600 mL) was added to the resulting mixture, which was then filtered. The residue was washed with methanol to obtain polymerizable liquid crystal compound (A-1) (15.8 g, 28.3 mmol). The yield was 94.2%. 1 H-NMR(CDCl3):δ=1.87(m,8H),3.16(t,2H),4.16(t,4H),4.29(t,4H),4.64(t,2H),5.87(dd,2H),6.14(dd,2H),6.44(dd,2 H),7.24(m,6H),7.38(d,2H),7.77(d,1H),7.80(m,1H),7.83(m,2H),8.00(dd,1H),8.21(dd,1H),8.55(s,1H),8.67(s,1H)

[0139] [ka]

[0140] (Synthesis of polymerizable liquid crystal compound (A-2)) With reference to Japanese Patent No. 5371422, a polymerizable liquid crystal compound (A-2) represented by the following chemical formula was synthesized.

[0141] [ka]

[0142] (Synthesis of polymerizable liquid crystal compound (A-3)) The polymerizable liquid crystal compound (A-3) was synthesized according to the following scheme.

[0143] [ka]

[0144] (1) Synthesis of Compound 3 6-Hydroxy-2-naphthoic acid (7.5 g, 39.9 mmol) and 1,4-diazabicyclo[2.2.2]octane (DABCO) (13.4 g, 119.6 mmol) were dissolved in dimethylformamide (DMF) (75 mL). N,N-dimethylthiocarbamoyl chloride (14.5 g, 119.6 mmol) was added to the resulting solution and stirred at 65 °C for 3 hours. The resulting solution was cooled to room temperature, and 1 M hydrochloric acid (150 mL) was added. The resulting mixture was filtered and washed with water. The resulting solid was reslurried and purified in methanol to give compound 3 (10.6 g, 38.5 mmol). The yield was 96.5%.

[0145] (2) Synthesis of Compound 4 Compound 3 (8.0 g, 29.1 mmol) was stirred at 230° C. for 3 hours. The resulting residue was purified by flash column chromatography to obtain compound 4 (7.9 g, 28.6 mmol) in a yield of 98.5%.

[0146] (3) Synthesis of Compound 5 Compound 4 (7.9 g, 28.6 mmol) was dissolved in methanol (40 mL). To the resulting solution was added an aqueous solution of potassium hydroxide (4.3 g, 85.8 mmol) (water; 40 mL), and the mixture was stirred at 70°C for 3 hours. The resulting solution was cooled to room temperature, methanol was evaporated under reduced pressure, and 1 M hydrochloric acid (120 mL) was added to the resulting residue. The resulting mixture was filtered and washed with water to obtain compound 5 (5.6 g, 27.3 mmol). The yield was 95.5%.

[0147] (4) Synthesis of Compound 6 Compound 5 (10 g, 47.0 mmol), 4-chlorobutyl acetate (21.2 g, 141.0 mmol), potassium carbonate (19.4 g, 141.0 mmol), and potassium iodide (0.8 g, 4.7 mmol) were mixed with DMAc (200 mL). The resulting mixture was stirred at 80°C for 3 hours. A solution of sodium hydroxide (9.4 g, 235.0 mmol) in 200 mL of water and 50 mL of methanol was added to the resulting mixture, and the mixture was stirred at 80°C for 3 hours. The resulting mixture was cooled to room temperature, the methanol was evaporated under reduced pressure, and 1 M hydrochloric acid (500 mL) was added to the resulting residue. Water and ethyl acetate were added to the resulting mixture, followed by extraction with ethyl acetate. The solvent in the resulting organic layer was evaporated under reduced pressure. The resulting solid was reslurried and purified with diisopropyl ether to give compound 6 (12.4 g, 44.9 mmol). The yield was 95.5%.

[0148] (5) Synthesis of Compound 7 Compound 6 (10.0 g, 36.1 mmol) and N,N-dimethylaniline (6.6 g, 54.2 mmol) were dissolved in THF (100 mL). The resulting solution was cooled to 10 °C, and acrylic acid chloride (4.9 g, 54.2 mmol) was added dropwise. The mixture was stirred at 10 °C for 1 hour. Water and ethyl acetate were added to the resulting mixture, followed by extraction with ethyl acetate. The solvent in the resulting organic layer was evaporated under reduced pressure. The resulting residue was recrystallized using toluene to give compound 7 (11.8 g, 35.7 mmol). The yield was 98.0%.

[0149] [ka]

[0150] (6) Synthesis of Compound 8 2-(4-Hydroxyphenyl)ethanol (4.1 g, 30.0 mmol) and thionyl chloride (10.7 g, 90.0 mmol) were dissolved in chloroform (30.0 mL) and stirred at room temperature for 3 hours. The resulting mixture was concentrated, and the residue was purified by flash column chromatography to give compound 8 (4.7 g, 30.0 mmol). The yield was 100.0%.

[0151] (7) Synthesis of Compound 9 Compound 8 (3.1 g, 20.0 mmol), 6-methoxy-2-naphthoic acid (3.0 g, 15.0 mmol), and DMAP (0.24 g, 2.0 mmol) were dissolved in CHCl (20 mL). The resulting solution was cooled to 15 °C, and N,N-diisopropylcarbodiimide (5.0 g, 40.0 mmol) was added dropwise. The mixture was stirred at 15 °C for 3 hours. Methanol (400 mL) was added to the resulting mixture, which was then filtered. The residue was washed with methanol to give compound 9 (6.2 g, 18.3 mmol). The yield was 91.5%.

[0152] (8) Synthesis of polymerizable liquid crystal compound (A-3) Compound 7 (3.3 g, 10.0 mmol), compound 9 (4.3 g, 12.5 mmol), potassium carbonate (1.7 g, 12.5 mmol), and potassium iodide (0.13 g, 0.02 mmol) were mixed with DMAc (40 mL). The resulting mixture was stirred at 80°C for 3 hours. Water and ethyl acetate were added to the resulting mixture, followed by extraction with ethyl acetate. The solvent in the resulting organic layer was evaporated under reduced pressure. The resulting residue was purified by flash column chromatography to obtain polymerizable liquid crystal compound (A-3) (6.3 g, 9.9 mmol). The yield was 98.8%. 1H-NMR(CDCl3):δ=1.93(m,4H),3.12(t,2H),3.20(t,2H),4.16(s,3H),4.29(t,2H),4.54(t,2H),5.85(dd,1H),6.14(dd,1H),6.4 0(dd,1H),7.20(m,6H),7.38(d,2H),7.77(d,1H),7.80(m,1H),7.85(m,2H),8.04(dd,1H),8.23(dd,1H),8.54(s,1H),8.68(s,1H)

[0153] [ka]

[0154] (Preparation of polymerizable liquid crystal compound (B-1)) A polymerizable liquid crystal compound (B-1) represented by the following chemical formula (manufactured by TCI, CAS RN: 132900-75-5, product code: D5936) was prepared.

[0155] [ka]

[0156] (Synthesis of Comparative Polymerizable Liquid Crystal Compound (C-1)) A comparative polymerizable liquid crystal compound (C-1) was synthesized according to the following scheme.

[0157] [ka]

[0158] (1) Synthesis of Compound 10 DMAc (500 mL) was added to 4-iodophenol (22.0 g, 100.0 mmol), 3-chloro-1-propanol (14.2 g, 150.0 mmol), potassium carbonate (20.7 g, 150.0 mmol), and potassium iodide (1.7 g, 10.0 mmol). The resulting mixture was stirred at 100°C for 3 hours. The resulting mixture was cooled to room temperature, and the methanol was removed under reduced pressure. 1 M hydrochloric acid (200 mL) was added to the resulting residue. Water and ethyl acetate were added to the resulting mixture, followed by extraction with ethyl acetate. The resulting residue was purified by flash column chromatography to give compound 10 (30.7 g, 95.5 mmol). The yield was 95.5%.

[0159] (2) Synthesis of Compound 11 Under an inert gas atmosphere, CuI (0.8 g, 4.0 mmol), PPh3 (2.1 g, 8.0 mmol), Pd(PPh3)2Cl2 (2.8 g, 4.0 mmol), dibutylhydroxytoluene (BHT) (0.2 g, 1.0 mmol), and Et3N (1000 mL) were mixed. The resulting mixture was cooled to 0 °C, and 5-bromo-2-iodotoluene (29.7 g, 100.0 mmol) and 4-ethynylanisole (15.9 g, 120.0 mmol) were added. The mixture was stirred at room temperature for 18 hours. Water and ethyl acetate were added to the resulting mixture, which was then extracted with ethyl acetate. The organic layer was evaporated under reduced pressure. The resulting residue was purified by flash column chromatography to give compound 11 (27.3 g, 98.0 mmol). The yield was 98.0%.

[0160] (3) Synthesis of Compound 12 Under an inert gas atmosphere, CuI (0.7 g, 3.8 mmol), PPh3 (2.0 g, 7.6 mmol), Pd(PPh3)2Cl2 (2.7 g, 3.8 mmol), BHT (0.2 g, 1.0 mmol), and Et3N (950 mL) were mixed. The resulting mixture was cooled to 0 °C, and compound 11 (26.4 g, 95.5 mmol) and 2-methyl-3-butyn-2-ol (20.0 g, 237.5 mmol) were added. The mixture was heated to reflux and stirred for 3 hours. Water and ethyl acetate were added to the resulting mixture, which was then extracted with ethyl acetate. The organic layer was evaporated under reduced pressure. The resulting residue was purified by flash column chromatography to give compound 12 (26.5 g, 87.9 mmol). The yield was 92.5%.

[0161] (4) Synthesis of Compound 13 Compound 12 (15.1 g, 50.0 mmol) was dissolved in toluene (50 mL) and cooled to 0°C. Sodium hydroxide (3.0 g, 75.0 mmol) was added to the resulting solution. The resulting mixture was stirred under reflux for 3 hours. The resulting mixture was cooled to room temperature, and 1 M hydrochloric acid (100 mL) and ethyl acetate were added. The mixture was then extracted with ethyl acetate. The solvent in the resulting organic layer was evaporated under reduced pressure. The residue was purified by flash column chromatography to give compound 13 (12.2 g, 49.5 mmol). The yield was 95.5%.

[0162] (5) Synthesis of Compound 14 Under an inert gas atmosphere, CuI (0.4 g, 2.0 mmol), PPh3 (1.1 g, 4.0 mmol), Pd(PPh3)2Cl2 (1.4 g, 2.0 mmol), BHT (0.2 g, 1.0 mmol), and Et3N (500 mL) were mixed. The resulting mixture was cooled to 0 °C, and compound 10 (13.6 g, 50.0 mmol) and compound 13 (14.8 g, 60 mmol) were added. The mixture was stirred at room temperature for 18 hours. Water and ethyl acetate were added to the resulting mixture, which was then extracted with ethyl acetate. The organic layer was evaporated under reduced pressure. The resulting residue was purified by flash column chromatography to give compound 14 (19.0 g, 48.0 mmol). The yield was 96.0%.

[0163] (6) Synthesis of comparative polymerizable liquid crystal compound (C-1) Compound 14 (15.9 g, 40 mmol) and N,N-dimethylaniline (5.8 g, 48.0 mmol) were dissolved in THF (100 mL). The resulting solution was cooled to 10°C, and acrylic acid chloride (4.3 g, 48.0 mmol) was added dropwise. The mixture was stirred at 10°C for 1 hour. Water and ethyl acetate were added to the resulting mixture, followed by extraction with ethyl acetate. The solvent in the resulting organic layer was evaporated under reduced pressure. The residue was purified by flash column chromatography to obtain comparative polymerizable liquid crystal compound (C-1) (17.6 g, 39.0 mmol). The yield was 97.5%. 1 H-NMR(CDCl3):δ=2.14(m,2H),2.49(s,3H),3.83(s,3H),4.07(t,2H),4.35(t,2H),5.82 (dd,1H),6.09(dd,1H),6.39(dd,1H),6.85(m,4H),7.28(d,1H),7.38(s,1H),7.42(m,5H)

[0164] [ka]

[0165] (Synthesis of Comparative Polymerizable Liquid Crystal Compound (C-2)) A comparative polymerizable liquid crystal compound (C-2) was synthesized according to the following scheme.

[0166] [ka]

[0167] (1) Synthesis of Compound 15 DMAc (500 mL) was added to 4-iodophenol (22.0 g, 100.0 mmol), 6-chloro-1-hexanol (20.5 g, 150.0 mmol), potassium carbonate (20.7 g, 150.0 mmol), and potassium iodide (1.7 g, 10.0 mmol). The resulting mixture was stirred at 100°C for 3 hours. The resulting mixture was cooled to room temperature, and the methanol was removed under reduced pressure. 1 M hydrochloric acid (200 mL) was added to the resulting residue. Water and ethyl acetate were added to the resulting mixture, followed by extraction with ethyl acetate. The resulting residue was purified by flash column chromatography to give compound 15 (30.4 g, 94.8 mmol). The yield was 94.8%.

[0168] (2) Synthesis of Compound 16 Under an inert gas atmosphere, CuI (0.4 g, 2.0 mmol), PPh3 (1.1 g, 4.0 mmol), Pd(PPh3)2Cl2 (1.4 g, 2.0 mmol), BHT (0.2 g, 1.0 mmol), and Et3N (500 mL) were mixed. The resulting mixture was cooled to 0 °C, and 1-bromo-3-fluoro-4-iodobenzene (15.0 g, 50.0 mmol) and 2-methyl-3-butyn-2-ol (21.0 g, 250.0 mmol) were added. The mixture was heated to reflux and stirred for 3 hours. Water and ethyl acetate were added to the resulting mixture, which was then extracted with ethyl acetate. The organic layer was evaporated under reduced pressure. The resulting residue was purified by flash column chromatography to give compound 16 (11.9 g, 45.8 mmol). The yield was 91.4%.

[0169] (3) Synthesis of Compound 17 Compound 16 (5.2 g, 20.0 mmol) was dissolved in toluene (20 mL) and cooled to 0°C. Sodium hydroxide (4.0 g, 100.0 mmol) was added to the resulting solution. The resulting mixture was stirred under reflux for 3 hours. The resulting mixture was cooled to room temperature, and 1 M hydrochloric acid (120 mL) and ethyl acetate were added. The mixture was then extracted with ethyl acetate. The solvent in the resulting organic layer was evaporated under reduced pressure. The residue was purified by flash column chromatography to give compound 17 (2.8 g, 19.4 mmol). The yield was 97.2%.

[0170] (4) Synthesis of Compound 18 Under an inert gas atmosphere, CuI (0.1 g, 0.6 mmol), PPh3 (0.3 g, 1.2 mmol), Pd(PPh3)2Cl2 (0.4 g, 0.6 mmol), BHT (0.03 g, 0.15 mmol), and Et3N (150 mL) were mixed. The resulting mixture was cooled to 0 °C, and compound 17 (2.2 g, 15.0 mmol) and compound 15 (14.4 g, 45.0 mmol) were added. The mixture was stirred at room temperature for 18 hours. Water and ethyl acetate were added to the resulting mixture, which was then extracted with ethyl acetate. The organic layer was evaporated under reduced pressure. The resulting residue was purified by flash column chromatography to give compound 18 (7.8 g, 14.8 mmol). The yield was 98.8%.

[0171] (5) Synthesis of comparative polymerizable liquid crystal compound (C-2) Compound 18 (7.8 g, 14.8 mmol) and N,N-dimethylaniline (5.4 g, 44.4 mmol) were dissolved in THF (50 mL). The resulting solution was cooled to 10°C, and acrylic acid chloride (4.0 g, 44.4 mmol) was added dropwise. The mixture was stirred at 10°C for 1 hour. Water and ethyl acetate were added to the resulting mixture, followed by extraction with ethyl acetate. The solvent in the resulting organic layer was evaporated under reduced pressure. The residue was purified by flash column chromatography to obtain comparative polymerizable liquid crystal compound (C-2) (9.2 g, 14.2 mmol) represented by the following chemical formula. The yield was 97.6%. 1H-NMR(CDCl3):δ=1.32(m,8H), 1.84(m,8H),4.08(t,4H),4.25(t,4H),5.80(dd,2H) ),6.11(dd,2H),6.36(dd,2H),6.83(m,4H),7.34(d,1H),7.44(m,5H),7.55(s,1H)

[0172] [ka]

[0173] [Preparation of the alignment film roll] A quartz master mold was fabricated using a 6-inch square synthetic quartz plate by an electron beam lithography process using an electron beam lithography system and a dry etching system. Next, an ultraviolet-curable resin was poured into the master mold, and then irradiated with ultraviolet light to harden the ultraviolet-curable resin. The ultraviolet-curable resin was then peeled off from the master mold to obtain a resin plate having a shape complementary to the surface shape of the master mold. Next, multiple replica molds of the master mold, which are molds having a shape complementary to the shape of the resin plate, were produced by electroforming. Next, the multiple replica molds were wound around a roll to produce a roll-shaped plate. Figure 5 is a schematic plan view showing the pattern shape of the alignment film used in the examples. The alignment film roll plate is a mold with a shape complementary to that of the alignment film. To form a pattern of recesses in the alignment film, the roll plate pattern is a pattern of protrusions. The protrusion pattern on the roll plate forms an arc-shaped pattern as shown in Figure 5, and one pitch is the distance it takes to rotate 180 degrees and return to the original rotation angle. P1 was 1.0 μm, P2 was 50 nm, the spacing between protrusions P3 was 25 nm, the protrusion width P4 was 25 nm, and the protrusion height was 30 nm. Each arc was divided into 360 protrusions, which were rotated 180 degrees at 0.5-degree intervals. The arc-shaped pattern was increased until a sufficient number of repetitions were achieved in both the x and y directions. In addition, for retardation measurement, a region was provided in part of the roll plate, in which the convex portions having the arc-shaped pattern were linear convex portions extending in one direction, but the spacing between the convex portions, the width, and the height of the convex portions were the same as those of the arc-shaped pattern. That is, a region was provided in which linear convex portions with a width of 25 nm and a height of 30 nm extended in the x direction and were repeatedly arranged parallel to each other with a spacing of 25 nm between the convex portions in the y direction. Furthermore, a region having an arc-shaped pattern similar to that described above was provided in part of the roll plate for orientation measurement, except that P1 was set to 3.5 μm.

[0174] [Examples 1 to 6: Production of optical elements] A primer layer having the following formulation was applied onto a substrate layer (a 40 μm thick cycloolefin polymer, Zeon Corporation's trade name "ZEONOR") and dried to form a primer layer having a thickness of 0.5 μm. <Coating liquid for forming primer layer> Polyolefin resin: 70 parts by weight (Mitsubishi Chemical Corporation, product name: Surflen P-1000) Silica-based lubricant: 5 parts by weight (Manufactured by CIK Nanotech, product name: SIRMIBK15WT%-E65) Methyl ethyl ketone: 25 parts by weight

[0175] Next, a coating liquid for forming an alignment film having the following formulation was applied onto the primer layer and dried to form a layer containing an uncured resin. <Coating liquid for forming alignment film> Pentaerythritol triacrylate: 96 parts by mass (Manufactured by Nippon Kayaku Co., Ltd., product name: PET-30) Photopolymerization initiator: 4 parts by mass (Manufactured by IGM RESINS BV, product name: Omnirad184)

[0176] Next, using the alignment film roll plate, a layer containing uncured resin was formed by a roll-to-roll method, and at the same time, ultraviolet light was irradiated from the substrate layer side to cure the formed layer containing resin. At this time, the cumulative light intensity of the ultraviolet light was 500 mJ / cm. 2 Next, the shaped layer was peeled off from the plate to obtain a laminate having a primer layer on the base layer and an alignment film having a shaped pattern on its surface.

[0177] Next, the following polymerizable liquid crystal composition for the optically anisotropic layer was applied to the alignment film having a shaped pattern on its surface by a continuous roll-to-roll method, and the liquid crystal compound was aligned by drying at 100°C for 60 seconds. Then, a cured film of the polymerizable liquid crystal composition was formed by irradiating with ultraviolet light. At this time, the cumulative light intensity of the ultraviolet light was 150 mJ / cm. 2 The optically anisotropic layer was formed by repeating the process of forming a cured film of the polymerizable liquid crystal composition for an optically anisotropic layer four times. In this way, an optical element was obtained which had, on the base layer, a primer layer, an alignment film, and a cured film (optically anisotropic layer) of a polymerizable liquid crystal composition in this order. <Polymerizable Liquid Crystal Composition for Optically Anisotropic Layer> Polymerizable liquid crystal compound: 100 parts by mass (the polymerizable liquid crystal compound shown in Table 1 was used in the parts by mass shown in Table 1) Photopolymerization initiator: 4 parts by mass (Manufactured by IGM RESINS BV, product name: Omnirad184) Cyclohexanone: 896 parts by mass

[0178] Comparative Examples 1 to 4: Production of Comparative Optical Elements A comparative optical element was produced in the same manner as in Example 1, except that in Example 1, the polymerizable liquid crystal compound in the polymerizable liquid crystal composition for the optically anisotropic layer was the polymerizable liquid crystal compound shown in Table 1, in the parts by mass shown in Table 1.

[0179] [evaluation] (1) Measurement of the thickness of the optically anisotropic layer The thickness of the optically anisotropic layer was determined by photographing a cross section of the optically anisotropic layer using a scanning transmission electron microscope (STEM) (S-4800, manufactured by Hitachi High-Technologies Corporation), measuring the thickness of the optically anisotropic layer at 10 points on the cross section image, and calculating the arithmetic mean value of the thicknesses at those 10 points. Cross-sectional photographs of the optically anisotropic layer were taken as follows. First, a 1 mm × 10 mm sample was embedded in an embedding resin to prepare a block. From this block, uniform, hole-free slices with a thickness of 70 nm to 100 nm were cut using a standard sectioning method. An ultramicrotome (Leica Microsystems, EM UC7) was used to prepare the slices. These uniform, hole-free slices were used as measurement samples. Cross-sectional photographs of the measurement samples were then taken using a scanning transmission electron microscope (STEM). STEM observations were performed using a detector set to "TE," an acceleration voltage of "30 kV," and an emission current of "10 μA." The magnification was adjusted from 5,000x to 200,000x, appropriately adjusting the focus and contrast and brightness to determine whether each layer could be distinguished.

[0180] (2) Refractive index anisotropy Δn 550 Refractive index anisotropy Δn 550 The polymerizable liquid crystal composition used in each example or comparative example was applied to an alignment film for retardation measurement, which had recesses formed in one direction, and dried at 100°C for 60 seconds to align the director (optical axis) of the liquid crystal compound so that it was horizontal to the surface of the support. After that, ultraviolet light was irradiated (integrated light amount 150 mJ / cm 2 ) to fix the polymerizable liquid crystal compound, thereby forming a cured film of the polymerizable liquid crystal composition. The optically anisotropic layer was formed by repeating the formation of a cured film of the polymerizable liquid crystal composition for the optically anisotropic layer four times. The in-plane retardation value (Re) and layer thickness of the obtained optically anisotropic layer were measured and determined. The layer thickness was measured by the method (1) above. The in-plane retardation value (Re) was measured at a wavelength of 550 nm using a product called "RETS-100" manufactured by Otsuka Electronics Co., Ltd., according to the following steps (A1) to (A4). (A1) First, the RETS-100 light source was left on for 60 minutes or more to stabilize. After that, the rotating analyzer method was selected, and one-point measurement was selected. (A2) Next, the following measurement conditions were set for the RETS-100. (Measurement conditions) Retardation measurement range: Rotating analyzer method Measurement spot diameter: φ5mm Tilt angle range: 0° Measurement wavelength range: 400nm to 800nm (A3) Next, background data was obtained without placing a sample in the device, which was a closed system, and was performed each time the light source was turned on. (A4) Then, the sample was placed on the stage inside the device and measured. From the obtained in-plane retardation value (Re(550)) at a wavelength of 550 nm and the layer thickness d (nm), the refractive index anisotropy Δn 550 asked for. Δn 550 =Re(550) / layer thickness d(nm)

[0181] (3) Orientation defects The alignment was determined by applying the polymerizable liquid crystal composition used in each example or comparative example onto an alignment film having an arc-shaped pattern with P1 of 3.5 μm, drying it at 100°C for 60 seconds, and aligning the director (optical axis) of the liquid crystal compound so that it was horizontal to the surface of the support, followed by irradiating it with ultraviolet light (integrated light dose 150 mJ / cm 2 ) to prepare a cured film (optically anisotropic layer) of the polymerizable liquid crystal compound having a layer thickness of 1.00 μm, which was then evaluated. Using a polarizing microscope (Olympus BX-51), the number of alignment defects in the cured film of the polymerizable liquid crystal compound was counted in a field of view of 100 μm × 100 μm. Only alignment defects caused by the measurement sample were counted, and defects caused by environmental foreign matter, etc. were excluded and not counted. (Evaluation criteria) A: The number of orientation defects is less than 10 B: The number of orientation defects is 10 or more and less than 35 C: Number of orientation defects is 35 or more

[0182] (4) Maximum wavelength of absorbance 1.0 (λ(1.0)), maximum absorption wavelength The absorption spectrum of the optically anisotropic layer was obtained by measuring the absorbance of the 1.00 μm-thick optically anisotropic layer used in the alignment defect measurement above at 1.0 nm intervals in the range of 200 nm to 800 nm using an ultraviolet-visible spectrophotometer (Shimadzu Corporation, UV-2700). In the absorption spectra of the optically anisotropic layers of Examples 1 to 3, in which the polymerizable liquid crystal compound (A) was present at 20 parts by mass, it was difficult to distinguish the maximum absorption wavelength on the long wavelength side. Therefore, the absorption spectra of each liquid crystal compound contained in the optically anisotropic layer were also measured. A 0.01 g / L solution of each liquid crystal compound (solvent: 1,3-dioxolane) was placed in a 1 cm quartz cell, and the absorbance was measured at 1.0 nm intervals in the range of 200 nm to 800 nm using a UV-visible spectrophotometer (Shimadzu Corporation, UV-2700). The maximum absorption wavelength on the long wavelength side was determined by taking the peak at an absorbance of 0.3 or more in the obtained absorption spectrum. The maximum absorption wavelength on the longest wavelength side was then determined for each liquid crystal compound contained in the optically anisotropic layer.

[0183] (5) Diffraction efficiency The diffraction angle and diffraction efficiency were determined using the optical elements of each example or comparative example as follows. A light source device 200 outputting laser light L having an output central wavelength of 530 nm was installed so that the laser light L was perpendicularly incident on one surface of the optical element OE (see FIG. 6). A screen was placed 100 cm away from the other surface of the optical element OE and parallel to that surface. The laser light L output from the light source device 200 was incident perpendicularly on one surface of the optical element 110, i.e., at an angle of 0° relative to the normal, and the transmitted light was captured on the screen. The exit angle θ of the transmitted light was calculated from the position of the transmitted light on the screen. The exit angle θ of the transmitted light is the diffraction angle θ, also referred to as the transmission angle θ. Next, as shown in FIG. 6, a photodetector 201 was installed at a position where it could receive the transmitted light, and the light intensity of the transmitted light Lt transmitted at the transmission angle θ was measured by the photodetector 201. Then, the ratio of the light intensity of the transmitted light Lt to the light intensity of the incident light (laser light L) was calculated to determine the relative light intensity value of the transmitted light Lt to the incident light (laser light L) (transmitted light Lt / laser light L). The diffraction efficiency was determined by multiplying the relative light intensity value of the transmitted light Lt to the incident light by 100 (%). The light intensity was measured after the laser light output from the light source was made perpendicular to a circular polarizer corresponding to its wavelength and circularly polarized, that is, after the circularly polarized laser light was made incident as incident light L into each optical element OE of the examples and comparative examples.

[0184] (6) Lightfastness The optical elements of each example or comparative example were subjected to light irradiation using an ultraviolet carbon arc light resistance tester (Fade Meter, manufactured by Suga Test Instruments Co., Ltd.) in an air atmosphere at a chamber temperature of 42°C, a relative humidity of 50%, and an illuminance of 500 W / m 2 A light resistance test was carried out under the condition that the exposure time was 48 hours. The diffraction efficiency was measured before and after the light resistance test, and the rate of change in the diffraction efficiency before and after the light resistance test was calculated using the following formula. Change in diffraction efficiency (%) = [100 × {| (after test) - (before test)|} / (before test) (Evaluation criteria) A: The rate of change in diffraction efficiency is less than 3% B: The rate of change in diffraction efficiency is 3% or more and less than 5% C: The rate of change in diffraction efficiency is 5% or more

[0185] [Table 1]

[0186] [Summary of results] In Examples 1 to 6, it was demonstrated that in an optical element in which a cured film of a polymerizable liquid crystal composition containing a specific polymerizable liquid crystal compound (A) has a liquid crystal orientation pattern in which the direction of the optical axis derived from the polymerizable liquid crystal compound is continuously rotated along at least one direction in the plane, orientation defects are suppressed, diffraction efficiency is improved, and light resistance in an air atmosphere is excellent. In contrast, in Comparative Example 1, it was shown that a cured film of a polymerizable liquid crystal composition not containing the specific polymerizable liquid crystal compound (A) had poor alignment and poor diffraction efficiency in an optical element having a liquid crystal alignment pattern in which the direction of the optical axis derived from the polymerizable liquid crystal compound was continuously rotated and changed along at least one direction in the plane. Furthermore, it was shown in Comparative Examples 2 to 4 that when a liquid crystal compound having a tolan structure was used, light resistance in an air atmosphere was poor. It was also shown in Comparative Examples 2 to 4 that when a cured film of a polymerizable liquid crystal composition not containing the specific polymerizable liquid crystal compound (A) was used, a large number of alignment defects occurred in the liquid crystal alignment pattern in which the direction of the optical axis derived from the polymerizable liquid crystal compound was continuously rotated along at least one direction in the plane, and the diffraction efficiency was poor.

Claims

1. The polymerizable liquid crystal compound (A) is represented by the following general formula (1): The liquid crystal display device further comprises an optically anisotropic layer which is a cured film of a polymerizable liquid crystal composition which may further contain a polymerizable liquid crystal compound (B) represented by the following general formula (2): An optical element, wherein a cured film of the polymerizable liquid crystal composition has a liquid crystal alignment pattern in which the direction of the optical axis derived from the polymerizable liquid crystal compound is continuously rotated and changed along at least one direction in the plane. 【Chemical 1】 (In the general formulas (1) and (2), Z １ , Z ２ , Z ３ , and Z ４ each independently represents a hydrogen atom, —CN, —NCS, an alkoxy group having 1 to 10 carbon atoms, or a polymerizable group; １ and Z ２ At least one of represents a polymerizable group, and Z ３ and Z ４ At least one of the groups represents a polymerizable group. R ｓｐ１ , R ｓｐ２ , R ｓｐ３ , and R ｓｐ４ each independently represents one —CH ２ - or two or more non-adjacent -CH ２ Each "-" independently represents an alkylene group having 1 to 20 carbon atoms which may be replaced by -O-, -COO-, -OCO-, -OCO-O-, -CO-NH-, -NH-CO-, or -CH=CH-, or a single bond. L １ , L ２ , L ３ , L ４ , L ５ , L ６ , L ７ , and L ８ are each independently —O—, —S—, or —OCH ２ -, -CH ２ O-, -CH ２ CH ２ -, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -OCO-NH-, -NH-COO-, -NH-CO-NH-, -NH-O-, -O-NH-, -SCH ２ -, -CH ２ S-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -COO-CH ２ CH ２ --, --OCO-CH ２ CH ２ -, -CH ２ CH ２ -COO-, -CH ２ CH ２ -OCO-, -COO-CH ２ --, --OCO-CH ２ -, -CH ２ -COO-, -CH ２ It represents —OCO—, —CH═CH—, or a single bond. Substituent E each independently represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylamino group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkanoyl group having 1 to 10 carbon atoms, an alkanoyloxy group having 1 to 10 carbon atoms, an alkanoylamino group having 1 to 10 carbon atoms, an alkanoylthio group having 1 to 10 carbon atoms, an alkyloxycarbonyl group having 2 to 10 carbon atoms, an alkylaminocarbonyl group having 2 to 10 carbon atoms, an alkylthiocarbonyl group having 2 to 10 carbon atoms, a hydroxy group, an amino group, a mercapto group, a carboxy group, a sulfo group, an amido group, a cyano group, a nitro group, a halogen atom, or a polymerizable group, provided that the above groups described as substituent E are not —CH ２ When the group has -, -CH contained in the above group ２ Groups in which at least one of - is replaced with -O-, -CO-, or -CH=CH- are also included in the substituent E. Furthermore, when the above groups described as the substituent E have a hydrogen atom, groups in which at least one of the hydrogen atoms contained in the above groups is replaced with at least one selected from the group consisting of a fluorine atom and a polymerizable group are also included in the substituent E. k1, k2, k3, and k4 each independently represent an integer of 0 to 4. n represents 1 or 2, m represents 1 or 3, and n' represents 0 or 1, and n x 2 + m + n' x 2 = 5 is satisfied. L ２ , L ３ , and L ６ When there are a plurality of each of the groups, they may be the same or different, and when there are a plurality of each of the groups, they may be the same or different.

2. 2. The optical element according to claim 1, wherein the optically anisotropic layer has an absorption spectrum of 200 nm to 500 nm, and the maximum wavelength at which the absorbance per 1.00 μm of layer thickness is 1.0 is 350 nm or less.

3. 3. The optical element according to claim 1, wherein the optically anisotropic layer has an absorption maximum wavelength on the long wavelength side of 270 nm or more and 320 nm or less in an absorption spectrum of 200 nm to 500 nm.

4. 3. The optical element according to claim 1, wherein the polymerizable liquid crystal compound (A) represented by the general formula (1) satisfies at least one of the following (i) to (iii): (i) m is 1 or 3, at least one k1 is 1, and E is a methyl group, a methoxycarbonyl group, or an ethoxycarbonyl group. (ii) n is 1, m is 1, and n′ is 1, and L １ and L ４ At least one of the groups is —O—CO—O—, —COO—, —OCO—, —O—, or —S—. (iii) n is 1, m is 1, and n′ is 1, and L ２ and L ３ At least one of the following is —COO—CH ２ CH ２ --, --OCO-CH ２ CH ２ -, -CH ２ CH ２ —COO— or —CH ２ CH ２ -OCO-.

5. 3. The optical element according to claim 1, wherein the optically anisotropic layer has a refractive index anisotropy Δn of 0.16 to 0.24 as measured with light having a wavelength of 550 nm.

6. 3. The optical element according to claim 1, wherein the optically anisotropic layer has a thickness of 1.00 μm or more.

7. 3. The optical element according to claim 1, wherein the polymerizable liquid crystal compound is cholesterically aligned in the thickness direction of the optically anisotropic layer.

8. 3. The optical element according to claim 1, wherein the optically anisotropic layer is laminated on an alignment film having a concavo-convex structure.

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