Optical film and head-mounted display

Abstract

The present invention addresses the problem of providing an optical film exhibiting the characteristic that the light transmittance in an oblique direction of a prescribed azimuth is higher than the light transmittance in an oblique direction of an azimuth orthogonal to the prescribed azimuth. This optical film includes, in the order given, a first light-absorbing anisotropic layer, a first optically anisotropic layer, a second optically anisotropic layer, and a second light-absorbing anisotropic layer. The angle formed by the transmittance center axis of the first light-absorbing anisotropic layer and the normal direction of the surface of the first light-absorbing anisotropic layer is 0-45°. The angle formed by the transmittance center axis of the second light-absorbing anisotropic layer and the normal direction of the surface of the second light-absorbing anisotropic layer is 0-45°. The in-plane retardation of the first optically anisotropic layer at a wavelength of 550 nm is 220-320 nm. The in-plane retardation of the second optically anisotropic layer at a wavelength of 550 nm is 220-320 nm. The angle formed by the in-plane slow axis of the first optically anisotropic layer and the in-plane slow axis of the second optically anisotropic layer is 55-80°.

Description

Optical film and head-mounted display

[0001] The present invention relates to an optical film and a head-mounted display including the optical film.

[0002] In recent years, head-mounted displays such as Augmented Reality (AR) glasses that project an image superimposed on a background have been put to practical use. The AR glasses have, for example, an image display element, a light guide plate, and a diffraction element. The image light emitted from the image display element is diffracted by the diffraction element, incident on the light guide plate, guided by the light guide plate, and the guided image light is diffracted by the diffraction element to display an image toward a viewer. The light guide plate is often transparent, and the AR glasses can project an image superimposed on a background.

[0003] Such AR glasses have a problem in that external light incident from a specific oblique direction is diffracted by the diffraction element toward the viewer, causing the viewer to see the external light reflected in a rainbow pattern, resulting in the appearance of rainbow unevenness. The specific oblique direction refers to a direction perpendicular (or substantially perpendicular) to the slit direction of the diffraction element. The angle of incidence (the oblique angle of incidence with respect to the main surface of the diffraction element) that is perceived varies depending on the pitch of the diffraction element, but the appearance of rainbow unevenness when external light is incident from an angle between 40° and 80° relative to the normal to the diffraction element is particularly problematic. For example, when using AR glasses or the like, with a diffraction element whose slit direction is close to horizontal, external light incident from above in front of the viewer's head is reflected and perceived as rainbow unevenness.

[0004] As a method for suppressing rainbow unevenness, a method of disposing a film that suppresses external light from being incident at the above angle relative to the normal of the diffraction element can be mentioned. As a film having such a function, for example, an optical laminate (optical film) having a first optically absorptive anisotropic layer, a first retardation layer, a second retardation layer, and a second optically absorptive anisotropic layer in this order, as described in Patent Document 1, can be mentioned. More specifically, Patent Document 1 discloses an optical laminate (optical film) in which the angle between the transmittance central axis of the first optically absorptive anisotropic layer and the normal direction of the surface of the first optically absorptive anisotropic layer is 0 °, the angle between the transmittance central axis of the second optically absorptive anisotropic layer and the normal direction of the surface of the second optically absorptive anisotropic layer is 0 °, the first retardation layer and the second retardation layer are λ / 2 wave plates, and the angle between the slow axis of the first retardation layer and the slow axis of the second retardation layer is within the range of 45 ± 10 °. In the optical film as described above, light in a direction tilted from the normal direction to the surface of the first optically absorptive anisotropic layer is less likely to be transmitted.

[0005] International Publication No. 2023 / 149359

[0006] When an optical film is applied to a head-mounted display or the like, it is sometimes required that the transmittance in an oblique direction at a predetermined azimuth angle be higher than the transmittance in an oblique direction at an azimuth angle orthogonal to the predetermined azimuth angle. The present inventors have studied the optical laminate (optical film) described in Patent Document 1 and found that it does not exhibit the above-mentioned characteristics and there is room for improvement.

[0007] Therefore, an object of the present invention is to provide an optical film that exhibits a higher transmittance in an oblique direction at a predetermined azimuth angle than the transmittance in an oblique direction at an azimuth angle orthogonal to the predetermined azimuth angle. Another object of the present invention is to provide a head-mounted display.

[0008] The present inventors have conducted extensive research to solve the above problems and have completed the present invention. That is, they have found that the above problems can be solved by the following configuration.

[0009] [1] An optical film having a first optically absorptive anisotropic layer, a first optically anisotropic layer, a second optically anisotropic layer, and a second optically absorptive anisotropic layer in this order, wherein the angle between the central transmittance axis of the first optically absorptive anisotropic layer and the normal to the surface of the first optically absorptive anisotropic layer is 0 to 45°, the angle between the central transmittance axis of the second optically absorptive anisotropic layer and the normal to the surface of the second optically absorptive anisotropic layer is 0 to 45°, the in-plane retardation of the first optically anisotropic layer at a wavelength of 550 nm is 220 to 320 nm, the in-plane retardation of the second optically anisotropic layer at a wavelength of 550 nm is 220 to 320 nm, and the angle between the in-plane slow axis of the first optically anisotropic layer and the in-plane slow axis of the second optically anisotropic layer is 55 to 80°. [2] An optical film having a first optically absorptive anisotropic layer, a third optically anisotropic layer, and a second optically absorptive anisotropic layer in this order, wherein the angle between the central transmittance axis of the first optically absorptive anisotropic layer and the normal direction to the surface of the first optically absorptive anisotropic layer is 0 to 45°, the angle between the central transmittance axis of the second optically absorptive anisotropic layer and the normal direction to the surface of the second optically absorptive anisotropic layer is 0 to 45°, the third optically anisotropic layer contains a liquid crystal compound that is twisted and aligned with a thickness direction of the third optically anisotropic layer as its helical axis, the twist angle of the liquid crystal compound is 140 to 220°, and the product Δnd of the refractive index anisotropy Δn of the third optically anisotropic layer and the thickness d of the third optically anisotropic layer is 300 to 600 nm.[3] An optical film having a first optically absorptive anisotropic layer, a fourth optically anisotropic layer, a fifth optically anisotropic layer, a sixth optically anisotropic layer, and a second optically absorptive anisotropic layer in this order, wherein the angle between the transmittance central axis of the first optically absorptive anisotropic layer and the normal direction to the surface of the first optically absorptive anisotropic layer is 0 to 45°, the angle between the transmittance central axis of the second optically absorptive anisotropic layer and the normal direction to the surface of the second optically absorptive anisotropic layer is 0 to 45°, the in-plane retardation of the fourth optically anisotropic layer at a wavelength of 550 nm is 100 to 250 nm, and the in-plane retardation of the fifth optically anisotropic layer at a wavelength of 550 nm is 100 to 250 nm. an angle formed by an in-plane slow axis of the fourth optically anisotropic layer and an in-plane slow axis of the fifth optically anisotropic layer is 20 to 55°; the sixth optically anisotropic layer contains a liquid crystal compound that is twisted and aligned with a helical axis in a thickness direction of the sixth optically anisotropic layer, the twist angle of the liquid crystal compound is 35 to 360°; and a product Δnd of a refractive index anisotropy Δn of the sixth optically anisotropic layer and a thickness d of the sixth optically anisotropic layer is 300 to 600 nm.[4] An optical film having a first optically absorptive anisotropic layer, a seventh optically anisotropic layer, an eighth optically anisotropic layer, a ninth optically anisotropic layer, a tenth optically anisotropic layer, and a second optically absorptive anisotropic layer in this order, wherein the angle between the transmittance central axis of the first optically absorptive anisotropic layer and the normal direction to the surface of the first optically absorptive anisotropic layer is 0 to 45°, the angle between the transmittance central axis of the second optically absorptive anisotropic layer and the normal direction to the surface of the second optically absorptive anisotropic layer is 0 to 45°, the in-plane retardation of the seventh optically anisotropic layer at a wavelength of 550 nm is 100 to 250 nm, and the in-plane retardation of the eighth optically anisotropic layer at a wavelength of 550 nm is 100 to 250 nm. [5] An optical film according to [4], further comprising an eleventh optically anisotropic layer between the seventh optically anisotropic layer and the eighth optically anisotropic layer, wherein the angle formed by the in-plane slow axis of the seventh optically anisotropic layer and the in-plane slow axis of the eighth optically anisotropic layer is 20 to 55°, the ninth optically anisotropic layer has an absolute value of retardation in the thickness direction at a wavelength of 550 nm of 100 to 300 nm, the tenth optically anisotropic layer contains a liquid crystal compound that is twisted and aligned with a helical axis in the thickness direction of the tenth optically anisotropic layer, the liquid crystal compound having a twist angle of 35 to 360°, and a product Δnd of a refractive index anisotropy Δn of the tenth optically anisotropic layer and a thickness d of the tenth optically anisotropic layer being 300 to 600 nm. [6] A head-mounted display comprising the optical film according to any one of [1] to [5].

[0010] According to the present invention, it is possible to provide an optical film that exhibits a higher transmittance in an oblique direction at a predetermined azimuth angle than the transmittance in an oblique direction at an azimuth angle orthogonal to the predetermined azimuth angle. Further, according to the present invention, it is possible to provide a head-mounted display.

[0011] 6 is a schematic diagram showing an example of a first embodiment of the optical film of the present invention. FIG. 1 is a diagram showing the azimuthal relationship of the in-plane slow axis directions when observed from the z-axis direction in FIG. 1. FIG. 2 is a diagram using a Poincaré sphere to explain the polarization conversion of light incident from the oblique direction DY shown in FIG. 1. FIG. 3 is a diagram using a Poincaré sphere to explain the polarization conversion of light incident from the oblique direction DX shown in FIG. 1. FIG. 6 is a schematic diagram showing an example of a second embodiment of the optical film of the present invention. FIG. 7 is a schematic diagram showing an example of a third embodiment of the optical film of the present invention. FIG. 8 is a diagram showing the azimuthal relationship of the in-plane slow axis directions when observed from the z-axis direction in FIG. 9. FIG. 10 is a diagram using a projection of the Poincaré sphere to explain the polarization conversion of light incident from the oblique direction DY shown in FIG. 10. FIG. 11 is a diagram using a projection of the Poincaré sphere to explain the polarization conversion of light incident from the oblique direction DX shown in FIG. 10. FIG. 12 is a schematic diagram showing an example of a fourth embodiment of the optical film of the present invention. FIG. 13 is a diagram showing the azimuthal relationship of the in-plane slow axis directions when observed from the z-axis direction in FIG. 14. FIG. 15 is a diagram using a projection of the Poincaré sphere to explain the polarization conversion of light incident from the oblique direction DY shown in FIG. 10. Fig. 11 is a diagram illustrating, using a projection diagram of the Poincare sphere, polarization conversion of light incident from the oblique direction DX shown in Fig. 10. Fig. 12 is a cross-sectional schematic diagram showing a part of AR glasses (a head-mounted display of the present invention).

[0012] The present invention will be described in detail below. The following description of the components may be based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.

[0013] The meaning of each description in this specification is as follows: In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0014] In this specification, parallel and perpendicular do not mean parallel and perpendicular in the strict sense, but rather mean a range of parallel ±5° and a range of perpendicular ±5°, respectively.

[0015] In addition, in this specification, for each component, a substance corresponding to the component may be used alone or in combination of two or more. Here, when two or more substances for each component are used in combination, the content of the component refers to the total content of the substances used in combination, unless otherwise specified.

[0016] In addition, in this specification, "(meth)acrylate" is a notation representing "acrylate" or "methacrylate", "(meth)acrylic" is a notation representing "acrylic" or "methacrylic", and "(meth)acryloyl" is a notation representing "acryloyl" or "methacryloyl".

[0017] In this specification, Re(λ) and Rth(λ) represent the in-plane retardation and the thickness direction retardation, respectively, at a wavelength λ. Unless otherwise specified, the wavelength λ is 550 nm. In the present invention, Re(λ) and Rth(λ) are values ​​measured at a wavelength λ using an AxoScan OPMF-2 (manufactured by Axometrics). By inputting the average refractive index ((nx + ny + nz) / 3) and film thickness (d (μm)) into the AxoScan, the following slow axis direction (°) is calculated: Re(λ) = R0(λ) Rth(λ) = ((nx + ny) / 2 - nz) × d. Note that R0(λ) is displayed as a numerical value calculated using the AxoScan OPMF-2, but it means Re(λ).

[0018] In this specification, the term "transmittance central axis" refers to the direction that exhibits the highest transmittance when the transmittance is measured by changing the tilt angle (polar angle) and tilt direction (azimuthal angle) relative to the normal direction of the optically absorptive anisotropic layer surface. Specifically, an AxoScan OPMF-2 (manufactured by Axometrics) is used to measure the Mueller matrix at a wavelength of 550 nm. More specifically, during measurement, the azimuthal angle at which the transmittance central axis is tilted is first found, and then, within a plane containing the normal direction of the optically absorptive anisotropic layer along that azimuthal angle (a plane containing the transmittance central axis and perpendicular to the layer surface), the polar angle, which is the angle relative to the normal direction of the optically absorptive anisotropic layer surface, is changed in 1° increments from -70 to 70°, while measuring the Mueller matrix at a wavelength of 550 nm, to derive the transmittance of the optically absorptive anisotropic layer. The resulting direction with the highest transmittance is designated the transmittance central axis. The transmittance central axis means the direction of the absorption axis (the direction of the long axis of the molecule) of the dichroic material contained in the light absorption anisotropic layer.

[0019] In this specification, the refractive indices nx, ny, and nz are measured using an Abbe refractometer (NAR-4T, manufactured by Atago Co., Ltd.) with a sodium lamp (λ = 589 nm) as a light source. Wavelength dependency can be measured using a multi-wavelength Abbe refractometer DR-M2 (manufactured by Atago Co., Ltd.) in combination with an interference filter. Values ​​from the Polymer Handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can also be used. Examples of average refractive index values ​​for major optical films are listed below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).

[0020] Furthermore, the bonding direction of a divalent group (for example, -COO-) represented in this specification is not particularly limited. For example, when L in X-LY is -COO-, assuming that the position bonding to the X side is *1 and the position bonding to the Y side is *2, L may be *1-O-CO-*2 or *1-CO-O-*2.

[0021] The optical film of the present invention may be exemplified by a first embodiment, a second embodiment, a third embodiment, and a fourth embodiment. Each embodiment will be described below.

[0022] <Optical Film (First Embodiment)> A first embodiment of the optical film of the present invention comprises a first optically absorptive anisotropic layer, a first optically anisotropic layer, a second optically anisotropic layer, and a second optically absorptive anisotropic layer, in this order. The angle between the central axis of transmittance of the first optically absorptive anisotropic layer and the normal to the surface of the first optically absorptive anisotropic layer is 0 to 45°. The angle between the central axis of transmittance of the second optically absorptive anisotropic layer and the normal to the surface of the second optically absorptive anisotropic layer is 0 to 45°. Furthermore, the in-plane retardation of the first optically anisotropic layer at a wavelength of 550 nm is 220 to 320 nm, and the in-plane retardation of the second optically anisotropic layer at a wavelength of 550 nm is 220 to 320 nm. The angle formed between the in-plane slow axis of the first optically anisotropic layer and the in-plane slow axis of the second optically anisotropic layer is 55 to 80°.

[0023] A first embodiment of the optical film of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an example of the first embodiment of the optical film of the present invention, and FIG. 2 is a diagram showing the azimuthal relationship of the in-plane slow axis direction when observed from the z-axis direction in FIG. 1. The optical film 10a shown in FIG. 1 has a first optically absorptive anisotropic layer 22, a first optically anisotropic layer 31, a second optically anisotropic layer 32, and a second optically absorptive anisotropic layer 24, in this order. The first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24 each contain a dichroic material. In FIG. 1, the angles formed between the central transmittance axes (corresponding to the hollow arrows in FIG. 1 ) of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24 and the normal direction to the surface of each optically absorptive anisotropic layer are both 0°. In Fig. 1 , the normal to the surface of the first optically absorptive anisotropic layer 22 is parallel to the z-axis direction, and the in-plane directions of each layer are parallel to the xy plane. The in-plane retardation of both the first optically anisotropic layer 31 and the second optically anisotropic layer 32 at a wavelength of 550 nm is 270 nm. In Fig. 1 , the angle formed by the in-plane slow axis direction D1 of the first optically anisotropic layer 31 and the in-plane slow axis direction D2 of the second optically anisotropic layer 32 is φ12 shown in Fig. 2 , and φ12 is 60°. The angle φ1 formed by the in-plane slow axis direction D1 and the x-axis direction is 30°, and the angle φ2 formed by the in-plane slow axis direction D2 and the x-axis direction is 30°.

[0024] This section explains that the optical film 10a shown in FIG. 1 exhibits a characteristic in which the transmittance in an oblique direction at a predetermined azimuth angle is higher than the transmittance in an oblique direction at an azimuth angle perpendicular to the predetermined azimuth angle. Hereinafter, this characteristic will also be referred to as "having oblique transmittance anisotropy." That is, this section explains that the optical film 10a shown in FIG. 1 exhibits high transmittance in a direction tilted by θ1 in the zx plane (the oblique direction DX in FIG. 1 ) from the z-axis direction (the transmittance central axis direction of the first optically absorptive anisotropic layer 22 and the transmittance central axis direction of the second optically absorptive anisotropic layer 24), and low transmittance in a direction tilted by θ2 in the yz plane from the z-axis direction (the oblique direction DY in FIG. 1 ). The absolute values ​​of the angles θ1 and θ2 are the same.

[0025] With respect to light incident from the oblique direction DY, the component polarized in the y-axis direction in FIG. 1 is easily absorbed by the dichroic material contained in the first optically absorptive anisotropic layer 22, and the component polarized in the x-axis direction is easily transmitted. Thus, the component polarized in the x-axis direction is mainly incident on the first optically anisotropic layer 31 from the oblique direction DY, undergoes polarization conversion, and exits the first optically anisotropic layer 31. The light exiting the first optically anisotropic layer 31 is incident on the second optically anisotropic layer 32 from the oblique direction DY, undergoes polarization conversion, and exits the second optically anisotropic layer 32. The light exiting the second optically anisotropic layer 32 is incident on the second optically absorptive anisotropic layer 24. The above polarization conversion will be explained using a Poincaré sphere.

[0026] 3 is a diagram illustrating the polarization conversion of light incident from the oblique direction DY shown in FIG. 1 using the Poincare sphere. First, as described above, the light from the oblique direction DY that has passed through the first optically absorptive anisotropic layer 22 is mainly composed of components polarized in the x-axis direction. １ The light represented by point P1a on the Poincaré sphere is incident on the first optically anisotropic layer 31 from the oblique direction DY. Since the in-plane slow axis direction D1 has a φ1 of 30° (see FIG. 2 ), when the first optically anisotropic layer 31 is viewed from the oblique direction DY, the angle between the in-plane slow axis direction D1 and the polarization direction of the x-axis incident from the oblique direction DY tends to be smaller than 30°. That is, the component of the polarization direction of the x-axis incident on the first optically anisotropic layer 31 from the oblique direction DY (point P1a on the Poincaré sphere) appears to be, for example, positioned such that the in-plane slow axis direction D1 is at an angle of approximately 22.5° clockwise with respect to the x-axis. The in-plane retardation of the first optically anisotropic layer 31 is 270 nm, which is approximately half the wavelength of 550 nm. Therefore, when a point P1a on the Poincare sphere is incident on the first optically anisotropic layer 31 from the oblique direction DY, the first optically anisotropic layer 31 causes the point P1a to be incident on the Poincare sphere at a point S ２ The light is converted into a polarization state represented by point P2a on the axis and emerges from the first optically anisotropic layer 31.

[0027] Next, light emitted from the first optically anisotropic layer 31 (point P2a on the Poincaré sphere) enters the second optically anisotropic layer 32 from the oblique direction DY. Since the in-plane slow axis direction D2 has a φ2 of 30° (see FIG. 2 ), when the second optically anisotropic layer 32 is viewed from the oblique direction DY, the angle between the in-plane slow axis direction D2 and the x-axis direction of the light entering from the oblique direction DY tends to be smaller than 30°. That is, the light entering the second optically anisotropic layer 32 from the oblique direction DY (point P2a on the Poincaré sphere) appears to have its in-plane slow axis direction D2 aligned at an angle of approximately 22.5° counterclockwise with respect to the x-axis. The in-plane retardation of the second optically anisotropic layer 32 is 270 nm, which is approximately half the wavelength of 550 nm. Therefore, when a point P2a on the Poincare sphere is incident on the second optically anisotropic layer 32 from the oblique direction DY, the second optically anisotropic layer 32 divides the incident light into a point S on the Poincare sphere. １ The light is converted into a polarization state represented by point P3a on the axis and having an opposite polarity to point P1a, and is emitted from the second optically anisotropic layer 32. That is, the light represented by point P1a is converted into linearly polarized light in the orthogonal direction by the first optically anisotropic layer 31 and the second optically anisotropic layer 32. In other words, the component of light polarized in the x-axis direction that enters the first optically absorptive anisotropic layer 22 from the oblique direction DY and exits the first optically absorptive anisotropic layer 22 is polarization converted by the first optically anisotropic layer 31 and the second optically anisotropic layer 32 and is converted into a component polarized in the y-axis direction.

[0028] As described above, the light emitted from the second optically anisotropic layer 32 in the oblique direction DY contains components polarized in the y-axis direction. In the light incident from the oblique direction DY, the components polarized in the y-axis direction in FIG. 1 are easily absorbed by the dichroic material contained in the second optically absorptive anisotropic layer 24, and the components polarized in the x-axis direction are easily transmitted. Therefore, the optical film 10a of the embodiment shown in FIG. 1 has low transmittance in the oblique direction DY.

[0029] On the other hand, for light incident from the oblique direction DX, the component polarized in the x-axis direction in FIG. 1 is easily absorbed by the dichroic material contained in the first optically absorptive anisotropic layer 22, and the component polarized in the y-axis direction is easily transmitted. As a result, mainly the component polarized in the y-axis direction enters the first optically anisotropic layer 31 from the oblique direction DX, undergoes polarization conversion, and exits the first optically anisotropic layer 31. The light exiting the first optically anisotropic layer 31 enters the second optically anisotropic layer 32 from the oblique direction DX, undergoes polarization conversion, and exits the second optically anisotropic layer 32. The light exiting the second optically anisotropic layer 32 enters the second optically absorptive anisotropic layer 24. The above polarization conversion will be explained using a Poincaré sphere.

[0030] 4 is a diagram using the Poincare sphere to explain the polarization conversion of light incident from the oblique direction DX shown in FIG. 1. First, as described above, the light from the oblique direction DX that has passed through the first optically absorptive anisotropic layer 22 is mainly a component polarized in the y-axis direction. １ The light represented by point P1b on the Poincaré sphere is incident on the first optically anisotropic layer 31 from the oblique direction DX. At this time, since the in-plane slow axis direction D1 has a φ1 of 30°, the angle between the y-axis direction and the in-plane slow axis direction D1 is 60° (see FIG. 2 ). Therefore, when the first optically anisotropic layer 31 is viewed from the oblique direction DX, the angle between the in-plane slow axis direction D1 and the polarization direction of the y-axis direction incident from the oblique direction DX tends to be smaller than 60°. In other words, the component of the polarization direction of the y-axis direction incident on the first optically anisotropic layer 31 from the oblique direction DX (point P1b on the Poincaré sphere) appears to be, for example, oriented such that the in-plane slow axis direction D1 is at an angle of approximately 50° counterclockwise with respect to the y-axis. The in-plane retardation of the first optically anisotropic layer 31 is 270 nm, which is approximately half the wavelength of 550 nm. Therefore, when point P1b on the Poincaré sphere enters the first optically anisotropic layer 31 from the oblique direction DX, the light is converted by the first optically anisotropic layer 31 into a polarization state represented by point P2b on the equator of the Poincaré sphere, and then exits the first optically anisotropic layer 31.

[0031] Next, light emitted from the first optically anisotropic layer 31 (point P2b on the Poincaré sphere) enters the second optically anisotropic layer 32 from the oblique direction DX. Since the in-plane slow axis direction D2 has a φ2 of 30°, the angle between the y-axis direction and the in-plane slow axis direction D1 is 60° (see FIG. 2 ). Therefore, when the second optically anisotropic layer 32 is viewed from the oblique direction DX, the angle between the in-plane slow axis direction D2 and the y-axis direction incident from the oblique direction DX tends to be smaller than 60°. That is, the light incident on the second optically anisotropic layer 32 from the oblique direction DX (point P2b on the Poincaré sphere) appears to be, for example, with the in-plane slow axis direction D2 oriented at approximately 50° clockwise with respect to the y-axis. The in-plane retardation of the second optically anisotropic layer 32 is 270 nm, which is approximately half the wavelength of 550 nm. Therefore, when the point P2b on the Poincare sphere is incident on the second optically anisotropic layer 32 from the oblique direction DX, the light is converted by the second optically anisotropic layer 32 into a polarization state represented by a point P3b on the equator of the Poincare sphere, and is emitted from the second optically anisotropic layer 32. The light represented by the point P3b is on the equator, and S １ The axis value is positive and S ２ Since the value of the y-axis is negative in this region, the light is linearly polarized and contains more components in the y-axis direction than components in the x-axis direction. That is, the component polarized in the y-axis direction that enters the first optically absorptive anisotropic layer 22 from the oblique direction DX and exits the first optically absorptive anisotropic layer 22 is subjected to polarization conversion by the first optically anisotropic layer 31 and the second optically anisotropic layer 32, and is converted into light that contains more components polarized in the y-axis direction.

[0032] As described above, the light emitted from the second optically anisotropic layer 32 in the oblique direction DX contains components polarized in the y-axis direction. Here, in the light incident from the oblique direction DX, the components polarized in the x-axis direction in FIG. 1 are easily absorbed by the dichroic material contained in the second optically absorptive anisotropic layer 24, and the components polarized in the y-axis direction are easily transmitted. As a result, the optical film 10a in the embodiment shown in FIG. 1 has a high transmittance in the oblique direction DX. That is, since the transmittance in the oblique direction DX is higher than the transmittance in the oblique direction DY, the optical film 10a in the embodiment shown in FIG. 1 has oblique transmittance anisotropy.

[0033] 1, it is easily understood that the first embodiment of the optical film of the present invention has oblique transmittance anisotropy, similar to the specific embodiment described above in Fig. 1. In the first embodiment of the optical film of the present invention, the transmittance is high in the direction of the transmittance central axes of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24. Furthermore, by adjusting the direction of the transmittance central axes of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24, the direction in which the transmittance is high can be adjusted.

[0034] Hereinafter, each component of the first embodiment of the optical film of the present invention will be described in detail.

[0035] [Lightly Absorbing Anisotropic Layer] A first embodiment of the optical film of the present invention includes two lightly absorbing anisotropic layers (a first lightly absorbing anisotropic layer 22 and a second lightly absorbing anisotropic layer 24). Hereinafter, when there is no need to distinguish between the two lightly absorbing anisotropic layers, they may be collectively referred to as "lightly absorbing anisotropic layers." In the lightly absorbing anisotropic layer, the angle between the central axis of transmittance of the lightly absorbing anisotropic layer and the normal direction of the lightly absorbing anisotropic layer is 0 to 45°, preferably 0° or more and less than 45°, more preferably 0° or more and 35° or less, and even more preferably 0° or more and less than 35°. It is preferable that the central axes of transmittance of the two lightly absorbing anisotropic layers are parallel to each other, from the viewpoint of improving light transmittance.

[0036] The optically absorptive anisotropic layer preferably contains a dichroic substance, more preferably contains a liquid crystal compound together with the dichroic substance, and further preferably is a layer in which the alignment states of the liquid crystal compound and the dichroic substance are fixed. Dichroic substances and liquid crystal compounds that are preferably contained in the optically absorptive anisotropic layer will be described below.

[0037] (Dichroic Material) In the present invention, the dichroic material means a dye whose absorbance varies depending on the direction. The dichroic material may or may not exhibit liquid crystallinity.

[0038] The dichroic substance is not particularly limited, and examples thereof include visible light absorbing substances (dichroic dyes), luminescent substances (fluorescent substances, phosphorescent substances), ultraviolet absorbing substances, infrared absorbing substances, nonlinear optical substances, carbon nanotubes, and inorganic substances (e.g., quantum rods), and any conventionally known dichroic substance (dichroic dye) can be used. Specifically, for example, paragraphs

[0067] to

[0071] of JP 2013-228706 A, paragraphs

[0008] to

[0026] of JP 2013-227532 A, paragraphs

[0008] to

[0015] of JP 2013-209367 A, paragraphs

[0045] to

[0058] of JP 2013-14883 A, paragraphs

[0012] to

[0029] of JP 2013-109090 A, paragraphs

[0009] to

[0017] of JP 2013-101328 A, Paragraphs

[0051] to

[0065] of JP 2013-037353 A, paragraphs

[0049] to

[0073] of JP 2012-063387 A, paragraphs

[0016] to

[0018] of JP 11-305036 A, paragraphs

[0009] to

[0011] of JP 2001-133630 A, paragraphs

[0030] to

[0169] of JP 2011-215337 A, paragraphs

[0021] to

[0075] of JP 2010-106242 A, paragraphs

[0016] to

[0018] of JP 2010-215846 A Paragraphs

[0011] to

[0025] , paragraphs

[0017] to

[0069] of JP 2011-048311 A, paragraphs

[0013] to

[0133] of JP 2011-213610 A, paragraphs

[0074] to

[0246] of JP 2011-237513 A, paragraphs

[0005] to

[0051] of JP 2016-006502 A, paragraphs

[0014] to

[0032] of JP 2018-053167 A, paragraphs

[0014] to

[0033] of JP 2020-011716 A paragraphs

[0005] to

[0041] of International Publication No. 2016 / 060173, paragraphs

[0008] to

[0062] of International Publication No. 2016 / 136561, paragraphs

[0014] to

[0033] of International Publication No. 2017 / 154835, paragraphs

[0014] to

[0033] of International Publication No. 2017 / 154695, paragraphs

[0013] to

[0037] of International Publication No. 2017 / 195833, and paragraphs

[0014] to

[0034] of International Publication No. 2018 / 164252;Examples include those described in paragraphs

[0021] to

[0030] of International Publication No. 2018 / 186503, paragraphs

[0043] to

[0063] of International Publication No. 2019 / 189345, paragraphs

[0043] to

[0085] of International Publication No. 2019 / 225468, paragraphs

[0050] to

[0074] of International Publication No. 2020 / 004106, and paragraphs

[0015] to

[0038] of International Publication No. 2021 / 044843.

[0039] As the dichroic substance, a dichroic azo dye compound is preferred. A dichroic azo dye compound refers to an azo dye compound whose absorbance varies depending on the direction. A dichroic azo dye compound may or may not exhibit liquid crystallinity. When a dichroic azo dye compound exhibits liquid crystallinity, it may exhibit either nematic or smectic properties. The temperature range in which the liquid crystal phase is exhibited is preferably room temperature (approximately 20 to 28°C) to 300°C, and more preferably 50 to 200°C from the viewpoints of handleability and manufacturing suitability.

[0040] In the present invention, from the viewpoint of adjusting color hue, it is preferable to use at least one dye compound (first dichroic azo dye compound) having a maximum absorption wavelength in the wavelength range of 560 to 700 nm, and at least one dye compound (second dichroic azo dye compound) having a maximum absorption wavelength in the wavelength range of 455 nm or more and less than 560 nm.

[0041] In the present invention, three or more kinds of dichroic azo dye compounds may be used in combination. For example, in order to make the light absorption anisotropic layer closer to black, it is preferable to use a first dichroic azo dye compound, a second dichroic azo dye compound, and at least one dye compound (third dichroic azo dye compound) having a maximum absorption wavelength in the wavelength range of 380 nm or more and less than 455 nm in combination.

[0042] In the present invention, the dichroic azo dye compound preferably has a crosslinkable group. Examples of the crosslinkable group include a (meth)acryloyl group, an epoxy group, an oxetanyl group, and a styryl group, and among these, a (meth)acryloyl group is preferred. The light absorption anisotropic layer may contain a cured product (crosslinked product) of a dichroic dye having a crosslinkable group (particularly, a dichroic dye compound having a crosslinkable group).

[0043] The content of the dichroic substance is not particularly limited, but is preferably 3% by mass or more, more preferably 8% by mass or more, even more preferably 10% by mass or more, and particularly preferably 10 to 30% by mass, of the total mass of the optically absorptive anisotropic layer, because this increases the degree of orientation of the optically absorptive anisotropic layer that is formed. When multiple dichroic substances are used in combination, the total amount of the multiple dichroic substances is preferably in the above-mentioned range.

[0044] (Liquid Crystal Compound) The light absorption anisotropic layer preferably contains a liquid crystal compound. This allows the dichroic material to be aligned with a higher degree of orientation while suppressing precipitation of the dichroic material. As the liquid crystal compound, either a polymer liquid crystal compound or a low molecular weight liquid crystal compound can be used, with the polymer liquid crystal compound being preferred because it allows for a higher degree of orientation. Furthermore, the liquid crystal compound may be a combination of a polymer liquid crystal compound and a low molecular weight liquid crystal compound. Here, "polymer liquid crystal compound" refers to a liquid crystal compound having a repeating unit in its chemical structure. Furthermore, "low molecular weight liquid crystal compound" refers to a liquid crystal compound having no repeating unit in its chemical structure. Examples of polymer liquid crystal compounds include the thermotropic liquid crystal polymers described in JP 2011-237513 A and the polymer liquid crystal compounds described in paragraphs

[0012] to

[0042] of WO 2018 / 199096 A. Examples of low molecular weight liquid crystal compounds include the liquid crystal compounds described in paragraphs

[0072] to

[0088] of JP-A-2013-228706, and among these, liquid crystal compounds exhibiting smectic properties are preferred.

[0045] The liquid crystal compound is preferably a polymer liquid crystal compound containing a repeating unit represented by the following formula (1) (hereinafter also abbreviated as "repeating unit (1)"), since this will result in a higher degree of orientation of the dichroic substance.

[0046]

[0047] In the above formula (1), P1 represents the main chain of the repeating unit, L1 represents a single bond or a divalent linking group, SP1 represents a spacer group, M1 represents a mesogenic group, and T1 represents a terminal group.

[0048] Examples of the main chain of the repeating unit represented by P1 include groups represented by the following formulae (P1-A) to (P1-D). Among these, the group represented by the following formula (P1-A) is preferred in terms of the variety of monomers that can be used as raw materials and ease of handling.

[0049]

[0050] In the above formulas (P1-A) to (P1-D), "*" represents the bonding position with L1 in the above formula (1). １ , R ２ , R ３ and R ４each independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms. The alkyl group may be a linear or branched alkyl group, or an alkyl group having a cyclic structure (a cycloalkyl group). The alkyl group preferably has 1 to 5 carbon atoms. The group represented by formula (P1-A) is preferably a unit of a partial structure of a poly(meth)acrylic acid ester obtained by polymerization of a (meth)acrylic acid ester. The group represented by formula (P1-B) is preferably an ethylene glycol unit formed by ring-opening polymerization of an epoxy group in a compound having an epoxy group. The group represented by formula (P1-C) is preferably a propylene glycol unit formed by ring-opening polymerization of an oxetane group in a compound having an oxetane group. The group represented by formula (P1-D) is preferably a siloxane unit of a polysiloxane obtained by condensation polymerization of a compound having at least one of an alkoxysilyl group and a silanol group. Here, the compound having at least one of an alkoxysilyl group and a silanol group is a compound represented by the formula SiR １４ (OR １５ ) ２ In the formula, R １４ is R in (P1-D) １４ and plural R １５ each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

[0051] In the above formula (1), L1 is a single bond or a divalent linking group. Examples of the divalent linking group represented by L1 include —C(O)O—, —O—, —S—, and —C(O)NR ３ -, -SO ２ - and -NR ３ R ４ In the formula, R ３ and R ４each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent. When P1 is a group represented by formula (P1-A), L1 is preferably a group represented by -C(O)O-, since this will result in a higher degree of orientation of the dichroic material. When P1 is a group represented by formulas (P1-B) to (P1-D), L1 is preferably a single bond, since this will result in a higher degree of orientation of the dichroic material.

[0052] In the above formula (1), the spacer group represented by SP1 preferably contains at least one structure selected from the group consisting of an oxyethylene structure, an oxypropylene structure, a polysiloxane structure, and a fluorinated alkylene structure, in view of the ease of exhibiting liquid crystallinity and the availability of raw materials.

[0053] In the above formula (1), the mesogenic group represented by M1 is a group that represents the main skeleton of the liquid crystal molecule that contributes to the formation of liquid crystals. The liquid crystal molecules exhibit liquid crystallinity, which is an intermediate state (mesophase) between a crystalline state and an isotropic liquid state. The mesogenic group is not particularly limited, and reference can be made, for example, to the description in "Flussige Kristalle in Tablellen II" (VEB Deutsche Verlag fur Grundstoff Industrie, Leipzig, published in 1984), particularly pages 7 to 16, and the description in "Liquid Crystal Handbook" edited by the Liquid Crystal Handbook Editorial Committee (Maruzen, published in 2000), particularly Chapter 3. As the mesogenic group, for example, a group having at least one cyclic structure selected from the group consisting of an aromatic hydrocarbon group, a heterocyclic group, and an alicyclic group is preferred. The mesogenic group preferably has an aromatic hydrocarbon group, more preferably has 2 to 4 aromatic hydrocarbon groups, and even more preferably has 3 aromatic hydrocarbon groups, in order to increase the degree of orientation of the dichroic substance.

[0054] In the above formula (1), examples of the terminal group represented by T1 include a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkoxycarbonyloxy group having 1 to 10 carbon atoms, an alkoxycarbonyl group having 1 to 10 carbon atoms (ROC(O)-: R is an alkyl group), an acyloxy group having 1 to 10 carbon atoms, an acylamino group having 1 to 10 carbon atoms, an alkoxycarbonylamino group having 1 to 10 carbon atoms, a sulfonylamino group having 1 to 10 carbon atoms, a sulfamoyl group having 1 to 10 carbon atoms, a carbamoyl group having 1 to 10 carbon atoms, a sulfinyl group having 1 to 10 carbon atoms, a ureido group having 1 to 10 carbon atoms, and a (meth)acryloyloxy group-containing group. Examples of the (meth)acryloyloxy group-containing group include a group represented by -LA (wherein L represents a single bond or a linking group. Specific examples of the linking group are the same as those of L1 and SP1 described above. A represents a (meth)acryloyloxy group).

[0055] T1 is preferably an alkoxy group having 1 to 10 carbon atoms, more preferably an alkoxy group having 1 to 5 carbon atoms, and even more preferably a methoxy group, in that the degree of orientation of the dichroic material is increased. These terminal groups may be further substituted with these groups or with the polymerizable groups described in JP-A-2010-244038.

[0056] T1 is preferably a polymerizable group, as this improves adhesion to adjacent layers and improves the cohesive strength of the film. The polymerizable group is not particularly limited, but a polymerizable group capable of radical polymerization or cation polymerization is preferred. The radical polymerizable group may be a commonly known radical polymerizable group, with preferred examples including an acryloyl group or a methacryloyl group. In this case, the acryloyl group is generally known to have a faster polymerization rate, and an acryloyl group is preferred from the viewpoint of improving productivity, but a methacryloyl group can also be used as the polymerizable group. The cationically polymerizable group may be a commonly known cationic polymerizable group, with specific examples including an alicyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro orthoester group, and a vinyloxy group. Among these, an alicyclic ether group or a vinyloxy group is preferred, with an epoxy group, an oxetanyl group, or a vinyloxy group being preferred.

[0057] The weight-average molecular weight (Mw) of the polymeric liquid crystal compound containing the repeating unit represented by formula (1) is preferably 1,000 to 500,000, more preferably 2,000 to 300,000, in order to increase the degree of orientation of the dichroic material. When the Mw of the polymeric liquid crystal compound is within the above range, the polymeric liquid crystal compound is easy to handle. In particular, in order to suppress cracking during application, the weight-average molecular weight (Mw) of the polymeric liquid crystal compound is preferably 10,000 or more, more preferably 10,000 to 300,000. Furthermore, in terms of the temperature latitude of the degree of orientation, the weight-average molecular weight (Mw) of the polymeric liquid crystal compound is preferably less than 10,000, and preferably 2,000 or more but less than 10,000. Here, the weight-average molecular weight and number-average molecular weight in the present invention are values ​​measured by gel permeation chromatography (GPC). Solvent (eluent): N-methylpyrrolidone Apparatus name: TOSOH HLC-8220GPC Column: Three TOSOH TSKgel Super AWM-H (6 mm x 15 cm) connected together Column temperature: 25°C Sample concentration: 0.1% by mass Flow rate: 0.35 mL / min Calibration curve: A calibration curve using seven samples of TSK standard polystyrene manufactured by TOSOH with Mw = 2,800,000 to 1,050 (Mw / Mn = 1.03 to 1.06) was used.

[0058] As the liquid crystal compound, a liquid crystal compound having reverse wavelength dispersion is also preferred. In this specification, "having reverse wavelength dispersion" means that a retardation film produced using this liquid crystal compound satisfies the relationships of the following formulas (X1) and (X2). Re(450) / Re(550)<1 (X1) 1<Re(630) / Re(550) (X2)

[0059] The reverse wavelength dispersion polymerizable liquid crystal compound is not particularly limited as long as it can form a reverse wavelength dispersion film, for example, the general formula (I) described in JP-A-2008-297210 compounds (particularly, compounds described in paragraphs

[0034] to

[0039] ), the general formula (1) described in JP-A-2010-084032 compounds (particularly, compounds described in paragraphs

[0067] to

[0073] ), the general formula (1) described in JP-A-2019-073496 compounds (particularly, compounds described in paragraphs

[0117] to

[0124] ), and the general formula (1) described in JP-A-2016-081035 compounds (particularly, compounds described in paragraphs

[0043] to

[0055] ).

[0060] The polymerizable group is not particularly limited, but a polymerizable group capable of radical polymerization or cation polymerization is preferred. Examples of the radical polymerizable group include known radical polymerizable groups, with acryloyl or methacryloyl groups being preferred. It is known that acryloyl groups generally have a faster polymerization rate, and acryloyl groups are preferred from the standpoint of improving productivity, but methacryloyl groups can also be used as polymerizable groups for high birefringence liquid crystals. Examples of the cationically polymerizable group include known cationic polymerizable groups, such as alicyclic ether groups, cyclic acetal groups, cyclic lactone groups, cyclic thioether groups, spiro orthoester groups, and vinyloxy groups. Among these, alicyclic ether groups or vinyloxy groups are preferred, with epoxy groups, oxetanyl groups, or vinyloxy groups being more preferred. Particularly preferred examples of the polymerizable group include polymerizable groups represented by any of the following formulas (P-1) to (P-20):

[0061]

[0062] The liquid crystal compound may have forward wavelength dispersion. In this specification, "having forward wavelength dispersion" means that a retardation film produced using this liquid crystal compound satisfies the relationships of the following formulas (Y1) and (Y2). Re(450) / Re(550)>1 (Y1) 1>Re(630) / Re(550) (Y2)

[0063] The liquid crystal compound has a forward wavelength dispersion property and has two polymerizable groups P １ and P ２ and a polymerizable group P selected from the group consisting of an aromatic ring and an alicyclic ring. １ and P ２ Three or more rings B present on the bond connecting １ A polymerizable liquid crystal compound having two polymerizable groups P １ and P ２ may be the same or different, and the polymerizable liquid crystal compound has three or more rings B １ may be the same or different.

[0064] Polymerizable group P possessed by the polymerizable liquid crystal compound １ and P ２ Although there are no particular limitations on the radical polymerizable group, a polymerizable group capable of radical polymerization or cationic polymerization is preferred. As the radical polymerizable group, a known radical polymerizable group can be used, and preferred examples include an acryloyloxy group or a methacryloyloxy group. In this case, it is known that the polymerization rate of an acryloyloxy group tends to be faster, and an acryloyloxy group is preferred from the viewpoint of improving productivity, but a methacryloyloxy group can also be used as the polymerizable group.

[0065] As the cationically polymerizable group, known cationically polymerizable groups can be used, and specific examples thereof include an alicyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro orthoester group, and a vinyloxy group. Among these, an alicyclic ether group or a vinyloxy group is preferred, and an epoxy group, an oxetanyl group, or a vinyloxy group is more preferred.

[0066] Particularly preferred examples of the polymerizable group include those represented by any of the above formulae (P-1) to (P-20).

[0067] The polymerizable liquid crystal compound may have three or more polymerizable groups. When the polymerizable liquid crystal compound has three or more polymerizable groups, the above-mentioned polymerizable group P １ and P ２The polymerizable group other than P is not particularly limited, and examples thereof include the same as the polymerizable group capable of radical polymerization or cationic polymerization as described above, including preferred embodiments thereof. The number of polymerizable groups possessed by the polymerizable liquid crystal compound is preferably 2 to 4, and the polymerizable group P １ and P ２ It is more preferable to have only two of the above.

[0068] The polymerizable liquid crystal compound is selected from the group consisting of an aromatic ring which may have a substituent and an alicyclic ring which may have a substituent, and the polymerizable group P １ and P ２ Three or more rings B present on the bond connecting １ wherein ring B １ is "polymerizable group P １ and P ２ "is present on the bond connecting the polymerizable group P １ and P ２ The polymerizable liquid crystal compound has a polymerizable group P １ and P ２ However, the ring structure constituting a part of the side chain may have a part other than the part necessary for directly linking the ring B １ shall not be included in the

[0069] Ring B １ An example of the aromatic ring which may have a substituent is an aromatic ring having 5 to 20 ring members which may have a substituent. Examples of the aromatic ring having 5 to 20 ring members include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring; and aromatic heterocycles such as a furan ring, a pyrrole ring, a thiophene ring, a pyridine ring, a thiazole ring, a benzothiazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, and a quinazoline ring.

[0070] Ring B １Examples of the substituent that the aromatic ring, which is one embodiment of the formula (1), may have include an alkyl group, an alkoxy group, an alkylcarbonyl group, an alkoxycarbonyl group, an alkylcarbonyloxy group, an alkylamino group, a dialkylamino group, an alkylamide group, an alkenyl group, an alkynyl group, a halogen atom, a cyano group, a nitro group, an alkylthiol group, and an N-alkylcarbamate group. Among these, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, or a halogen atom is preferred.

[0071] The alkyl group is preferably a linear, branched, or cyclic alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, and cyclohexyl), still more preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl or ethyl group. The alkoxy group is preferably an alkoxy group having 1 to 18 carbon atoms, more preferably an alkoxy group having 1 to 8 carbon atoms (e.g., methoxy, ethoxy, n-butoxy, and methoxyethoxy), still more preferably an alkoxy group having 1 to 4 carbon atoms, and particularly preferably a methoxy or ethoxy group. Examples of the alkoxycarbonyl group include a group in which an oxycarbonyl group (-O-CO- group) is bonded to the alkyl group exemplified above, with a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, or an isopropoxycarbonyl group being preferred, and a methoxycarbonyl group being more preferred. Examples of the alkylcarbonyloxy group include a group in which a carbonyloxy group (-CO-O- group) is bonded to the alkyl group exemplified above, with a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, or an isopropylcarbonyloxy group being preferred, and a methylcarbonyloxy group being more preferred. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom or a chlorine atom being preferred.

[0072] Ring B １The optionally substituted alicyclic ring, which is one embodiment of the above, includes a divalent alicyclic hydrocarbon group having 5 to 20 carbon atoms which may have a substituent, and a —CH ２ Examples of such heterocyclic groups include heterocycles in which one or more - groups are substituted with -O-, -S-, or -NH-. As the divalent alicyclic hydrocarbon group having 5 to 20 carbon atoms, a 5- or 6-membered ring is preferred. Furthermore, the alicyclic hydrocarbon group may be saturated or unsaturated, but a saturated alicyclic hydrocarbon group is preferred. For examples of divalent alicyclic hydrocarbon groups, see, for example, paragraph

[0078] of JP 2012-021068 A, the contents of which are incorporated herein by reference.

[0073] Ring B １ The alicyclic ring, which is one embodiment of the above, is preferably a cycloalkane ring having 5 to 20 carbon atoms. Examples of the cycloalkane ring having 5 to 20 carbon atoms include a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a cyclododecane ring, and a cyclodocosane ring. Of these, a cyclohexane ring is preferred, a 1,4-cyclohexylene group is more preferred, and a trans-1,4-cyclohexylene group is even more preferred.

[0074] Ring B １ The substituents that the alicyclic ring may have include those of the ring B, including preferred embodiments thereof. １ The substituents may be the same as those that may be possessed by the aromatic ring which is one embodiment of Ring B. １ The alicyclic ring, which is one embodiment of the above, preferably has no substituent.

[0075] The polymerizable liquid crystal compound has ring B １ As the ring B, it is preferable that the polymerizable liquid crystal compound has at least one aromatic ring which may have a substituent, and it is more preferable that the polymerizable liquid crystal compound has at least one group represented by the formula (III) described below. １ As the ring B, it is preferable that the polymerizable liquid crystal compound has at least one cyclohexane ring, more preferably has at least one 1,4-cyclohexylene group, and further preferably has at least one trans-1,4-cyclohexylene group. １As the 1,4-cyclohexylene group, it is preferable that the 1,4-cyclohexylene group has a combination of at least one aromatic ring (more preferably a group represented by formula (III) described later) and at least one cyclohexane ring (more preferably 2 to 4 1,4-cyclohexylene groups).

[0076] In the polymerizable liquid crystal compound, the polymerizable group P １ and P ２ Ring B present on the bond connecting １ The number of is not particularly limited, but is preferably 3 to 7, more preferably 4 to 6, and even more preferably 5, from the viewpoint of the alignment stability of the liquid crystal compound.

[0077] (Other Components) The optically absorptive anisotropic layer may contain components other than those described above, such as a vertical alignment agent and a leveling agent.

[0078] Examples of the vertical alignment agent include boronic acid compounds and onium salts. As the boronic acid compound, a compound represented by formula (A) is preferred.

[0079] Formula (A)

[0080] In formula (A), R １ and R ２ R each independently represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. ３ represents a substituent containing a (meth)acrylic group. Specific examples of the boronic acid compound include the boronic acid compound represented by general formula (I) described in paragraphs

[0023] to

[0032] of JP-A No. 2008-225281.

[0081] The onium salt is preferably a compound represented by formula (B).

[0082] Formula (B)

[0083] In formula (B), ring A represents a quaternary ammonium ion consisting of a nitrogen-containing heterocycle. － represents an anion. １ represents a divalent linking group. ２represents a single bond or a divalent linking group. １ represents a divalent linking group having a 5- or 6-membered ring as a partial structure. Z represents a divalent linking group having 2 to 20 alkylene groups as a partial structure. P １ and P ２ each independently represent a monovalent substituent having a polymerizable ethylenically unsaturated bond. Specific examples of the onium salt include the onium salts described in paragraphs

[0052] to

[0058] of JP-A No. 2012-208397, the onium salts described in paragraphs

[0024] to

[0055] of JP-A No. 2008-026730, and the onium salts described in JP-A No. 2002-037777.

[0084] When the optically absorptive anisotropic layer contains a vertical alignment agent, the content of the vertical alignment agent is preferably 0.1 to 400% by mass, more preferably 0.5 to 350% by mass, based on the total mass of the liquid crystal compound. The vertical alignment agent may be used alone or in combination of two or more. When two or more types of vertical alignment agents are used, the total amount thereof is preferably in the above range.

[0085] The optically absorptive anisotropic layer may contain a leveling agent. When the optically absorptive anisotropic layer-forming composition (optically absorptive anisotropic layer) described below contains a leveling agent, surface roughness caused by dry air on the surface of the optically absorptive anisotropic layer is suppressed, and the dichroic material is more uniformly oriented. The leveling agent is not particularly limited, and a leveling agent containing a fluorine atom (a fluorine-based leveling agent) or a leveling agent containing a silicon atom (a silicon-based leveling agent) is preferred.

[0086] Examples of fluorine-based leveling agents include fatty acid esters of polycarboxylic acids in which a portion of the fatty acid is substituted with a fluoroalkyl group, and polyacrylates having a fluoro substituent.

[0087] Specific examples of the leveling agent include the compounds exemplified in paragraphs

[0046] to

[0052] of JP-A No. 2004-331812 and the compounds described in paragraphs

[0038] to

[0052] of JP-A No. 2008-257205.

[0088] When the light absorption anisotropic layer contains a liquid crystal compound and a leveling agent, the content of the leveling agent is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, based on the total mass of the liquid crystal compound. The leveling agents may be used alone or in combination of two or more. When two or more leveling agents are used, the total amount thereof is preferably in the above range.

[0089] (Composition for forming optically absorptive anisotropic layer) The optically absorptive anisotropic layer is preferably formed using a composition for forming an optically absorptive anisotropic layer containing a dichroic substance and a liquid crystal compound. The composition for forming an optically absorptive anisotropic layer preferably contains a solvent described below in addition to the dichroic substance and the liquid crystal compound, and may further contain other components described above.

[0090] The dichroic substance contained in the composition for forming an optically absorptive anisotropic layer includes a dichroic substance that can be contained in the optically absorptive anisotropic layer. The content of the dichroic substance relative to the total solid mass of the composition for forming an optically absorptive anisotropic layer is preferably the same as the content of the dichroic substance relative to the total mass of the optically absorptive anisotropic layer. Here, "total solids in the composition for forming an optically absorptive anisotropic layer" refers to components excluding the solvent, and specific examples of solids include the dichroic substance, the liquid crystal compound, and the other components described above.

[0091] The liquid crystal compound and other components that can be contained in the composition for forming an optically absorptive anisotropic layer are the same as those that can be contained in the optically absorptive anisotropic layer, and the content of the liquid crystal compound and other components relative to the total solid mass of the composition for forming an optically absorptive anisotropic layer is preferably the same as the content of the liquid crystal compound and other components relative to the total mass of the optically absorptive anisotropic layer.

[0092] From the viewpoint of workability, the composition for forming the optically absorptive anisotropic layer preferably contains a solvent. Examples of the solvent include organic solvents such as ketones, ethers, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated carbons, esters, alcohols, cellosolves, cellosolve acetates, sulfoxides, amides, and heterocyclic compounds, as well as water. These solvents may be used alone or in combination of two or more. Among these solvents, organic solvents are preferred, and halogenated carbons or ketones are more preferred.

[0093] When the composition for forming an optically absorptive anisotropic layer contains a solvent, the content of the solvent is preferably 80 to 99 mass %, more preferably 83 to 97 mass %, and even more preferably 85 to 95 mass %, based on the total mass of the composition for forming an optically absorptive anisotropic layer.

[0094] The composition for forming an optically absorptive anisotropic layer may contain a polymerization initiator. The polymerization initiator is not particularly limited, but is preferably a photosensitive compound, i.e., a photopolymerization initiator. Commercially available photopolymerization initiators such as Irgacure 184, Irgacure 907, Irgacure 369, Irgacure 651, Irgacure 819, Irgacure OXE-01, and Irgacure OXE-02, manufactured by BASF, can also be used. The polymerization initiators may be used alone or in combination of two or more. When the composition for forming an optically absorptive anisotropic layer contains a polymerization initiator, the content of the polymerization initiator is preferably 0.01 to 30% by mass, more preferably 0.1 to 15% by mass, based on the total solid content of the composition for forming an optically absorptive anisotropic layer.

[0095] (Method for manufacturing optically absorbing anisotropic layer) The method for manufacturing an optically absorbing anisotropic layer is not particularly limited. However, in order to increase the degree of orientation of the dichroic material, a method (hereinafter also referred to as the present manufacturing method) that includes, in order, a step of forming a coating film by applying a composition for forming an optically absorbing anisotropic layer containing a dichroic material and a liquid crystal compound onto an alignment film (hereinafter also referred to as the "coating film forming step"), and a step of orienting the liquid crystal component contained in the coating film (hereinafter also referred to as the "orientation step") is preferred. Note that the liquid crystal component is a component that includes not only the above-mentioned liquid crystal compound but also a dichroic material having liquid crystal properties. Each step will be described below.

[0096] The coating film forming step is a step of forming a coating film by applying the above-mentioned optically absorbing anisotropic layer-forming composition onto an alignment film. By using the optically absorbing anisotropic layer-forming composition containing the above-mentioned solvent, or by using the optically absorbing anisotropic layer-forming composition in a liquid form such as a molten liquid by heating, it becomes easy to apply the optically absorbing anisotropic layer-forming composition onto the alignment film. Examples of methods for applying the optically absorbing anisotropic layer-forming composition include known methods such as roll coating, gravure printing, spin coating, wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spraying, and inkjet printing.

[0097] The alignment film may be any film that aligns the liquid crystal component that may be contained in the composition for forming the optically absorptive anisotropic layer. It can be formed by methods such as rubbing an organic compound (preferably a polymer) onto the film surface, oblique vapor deposition of an inorganic compound, formation of a layer with microgrooves, or accumulation of an organic compound (e.g., ω-tricosanoic acid, dioctadecylmethylammonium chloride, methyl stearate) using the Langmuir-Blodgett method (LB film). Furthermore, alignment films that exhibit alignment function upon application of an electric field, a magnetic field, or light irradiation are also known. Among these, alignment films made of polyvinyl alcohol resins are preferred in the present invention, and photo-alignment films formed by light irradiation are also preferred in terms of uniformity of alignment.

[0098] The photo-alignment film may contain an azobenzene dye or polyvinyl cinnamate. UV light is irradiated from an oblique direction at an angle to the normal to the photo-alignment film, generating anisotropy with a tilt relative to the normal to the photo-alignment film. By aligning a light-absorbing anisotropic layer on top of this, the dichroic material in the light-absorbing anisotropic layer can be aligned. Alternatively, a liquid crystal layer in which liquid crystal compounds are hybrid-aligned can also be used as the alignment film.

[0099] The orientation process is a process for orienting the liquid crystal components (especially the dichroic material) contained in the coating film. In the orientation process, it is considered that the dichroic material is oriented along the liquid crystal compound oriented by the orientation film. The orientation process may include a drying process. The drying process can remove components such as solvent from the coating film. The drying process may be performed by leaving the coating film at room temperature for a predetermined time (for example, natural drying), or by heating and / or blowing air.

[0100] The orientation step preferably includes a heat treatment. This further aligns the dichroic material contained in the coating film, thereby increasing the degree of orientation of the dichroic material. From the viewpoint of manufacturability, the heat treatment is preferably performed at a temperature of 10 to 250°C, more preferably 25 to 190°C. The heating time is preferably 1 to 300 seconds, more preferably 1 to 60 seconds.

[0101] The orientation step may include a cooling treatment carried out after the heating treatment. The cooling treatment is a treatment in which the coated film after heating is cooled to about room temperature (20 to 25°C). This further fixes the orientation of the dichroic material contained in the coated film, thereby increasing the degree of orientation of the dichroic material. The cooling method is not particularly limited and can be carried out by a known method. The optically absorptive anisotropic layer of the present invention can be obtained by the above steps.

[0102] The present manufacturing method may include a step of curing the optically absorptive anisotropic layer (hereinafter also referred to as a "curing step") after the alignment step. The curing step is performed, for example, by heating and / or light irradiation (exposure). Among these, the curing step is preferably performed by light irradiation. Various light sources such as infrared light, visible light, or ultraviolet light can be used as the light source for curing, but ultraviolet light is preferred. Furthermore, ultraviolet light may be irradiated while heating during curing, or ultraviolet light may be irradiated through a filter that transmits only specific wavelengths. Furthermore, exposure may be performed in a nitrogen atmosphere. When the curing of the optically absorptive anisotropic layer proceeds by radical polymerization, exposure in a nitrogen atmosphere is preferred because inhibition of polymerization by oxygen is reduced.

[0103] The thickness of the optically absorptive anisotropic layer is not particularly limited, but is preferably from 0.5 to 7 μm, more preferably from 1.0 to 3 μm, in terms of achieving better effects of the present invention.

[0104] [Optically Anisotropic Layer] The optical film of the first embodiment of the present invention includes two optically anisotropic layers (a first optically anisotropic layer 31 and a second optically anisotropic layer 32) between two light-absorption anisotropic layers. Hereinafter, when there is no need to distinguish between the two optically anisotropic layers, they may be collectively referred to as "optically anisotropic layers." The optically anisotropic layer is as described above. The angle between the in-plane slow axis directions of the two optically anisotropic layers is also as described above.

[0105] The material for forming the optically anisotropic layer is not particularly limited, and examples thereof include an optically anisotropic layer containing a liquid crystal compound and a stretched film. Of these, the optically anisotropic layer is preferably an optically anisotropic layer containing a liquid crystal compound.

[0106] Liquid crystal compounds can generally be classified into rod-shaped and discotic types based on their shape. Furthermore, each can be divided into low-molecular-weight and high-molecular-weight types. A high-molecular-weight compound generally refers to a compound with a degree of polymerization of 100 or more (see "Polymer Physics: Phase Transition Dynamics," by Masao Doi, p. 2, Iwanami Shoten, 1992). While any liquid crystal compound can be used in the present invention, rod-shaped or discotic liquid crystal compounds (discotic liquid crystal compounds) are preferred. Furthermore, monomers or liquid crystal compounds with relatively low molecular weights and a degree of polymerization of less than 100 are preferred. Examples of polymerizable groups possessed by polymerizable liquid crystal compounds include acryloyl groups, methacryloyl groups, epoxy groups, and vinyl groups. The orientation of such polymerizable liquid crystal compounds can be fixed by polymerization. Note that once the liquid crystal compound is fixed by polymerization, it no longer needs to exhibit liquid crystallinity.

[0107] Preferred rod-shaped liquid crystal compounds include azomethines, azoxy compounds, cyanobiphenyls, cyanophenyl esters, benzoates, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes, and alkenylcyclohexylbenzonitriles. These rod-shaped liquid crystal compounds are fixed by introducing a polymerizable group into the terminal structure of the rod-shaped liquid crystal compound (as with the discotic liquid crystals described below), followed by polymerization and curing. A specific example is described in JP-A No. 2006-209073, in which a polymerizable nematic rod-shaped liquid crystal compound is cured with ultraviolet light. In addition to the low-molecular-weight liquid crystal compounds described above, polymeric liquid crystal compounds can also be used. Polymeric liquid crystal compounds are polymers having side chains corresponding to the low-molecular-weight liquid crystal compounds described above. Optical compensation sheets using polymeric liquid crystal compounds are described in JP-A No. 5-053016, for example.

[0108] Examples of discotic liquid crystal compounds include benzene derivatives described in the research report by C. Destrade et al., Mol. Cryst., Vol. 71, p. 111 (1981), truxene derivatives described in the research report by C. Destrade et al., Mol. Cryst., Vol. 122, p. 141 (1985) and Physicslett, A, Vol. 78, p. 82 (1990), cyclohexane derivatives described in the research report by B. Kohne et al., Angew. Chem., Vol. 96, p. 70 (1984), and compounds described in the research report by J. M. Lehn et al., J. Chem. Commun., p. 1794 (1985), and the research report by J. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994) include azacrown and phenylacetylene macrocycles.

[0109] The discotic liquid crystal compound molecules also include compounds exhibiting liquid crystallinity in which linear alkyl groups, alkoxy groups, or substituted benzoyloxy groups are radially substituted as side chains around the mother nucleus at the center of the molecule. Compounds in which the molecules or molecular aggregates have rotational symmetry and can impart a specific orientation are preferred. Optically anisotropic layers formed from compositions containing discotic liquid crystal compounds do not necessarily exhibit liquid crystallinity when ultimately incorporated into the optically anisotropic layer. For example, low-molecular-weight discotic liquid crystal molecules having heat- or light-reactive groups lose their liquid crystallinity when polymerized by heating or light irradiation. However, optically anisotropic layers containing such highly polymerized compounds can also be used in the present invention. Preferred examples of discotic liquid crystal compounds include those described in JP-A-8-050206. Furthermore, the polymerization of discotic liquid crystal molecules is described in JP-A-8-027284.

[0110] In order to fix discotic liquid crystal molecules by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystal molecule. A compound in which the discotic core and the polymerizable group are bonded via a linking group is preferred, and this allows the alignment state to be maintained even during the polymerization reaction. Examples thereof include compounds described in paragraphs

[0151] to

[0168] of JP-A No. 2000-155216.

[0111] In the optical film of the first embodiment of the present invention, at least one optically anisotropic layer may be formed using a composition containing a discotic liquid crystal compound. Of the two optically anisotropic layers, it is also preferred that one optically anisotropic layer is formed using a composition containing a discotic liquid crystal compound, and the other optically anisotropic layer is formed using a composition containing a rod-shaped liquid crystal compound. Alternatively, the two optically anisotropic layers may be formed using a composition containing a discotic liquid crystal compound.

[0112] In the optical film of the first embodiment of the present invention, it is also preferable that at least one of the optically anisotropic layers is a layer formed using a composition containing a rod-shaped liquid crystal compound with reverse wavelength dispersion, because this can suppress color change. Examples of such rod-shaped liquid crystal compounds with reverse wavelength dispersion include those described above as any liquid crystal compound contained in the light absorption anisotropic layer (particularly, polymerizable liquid crystal compounds with reverse wavelength dispersion).

[0113] In addition, for the reasons of improving the light blocking ability of obliquely incident light and suppressing color change, it is also preferred that one of the two optically anisotropic layers is formed using a composition containing a rod-shaped liquid crystal compound, and the other optically anisotropic layer is formed using a composition containing a discotic liquid crystal compound.It is also preferred that one of the two optically anisotropic layers is formed using a composition containing a rod-shaped liquid crystal compound with reverse wavelength dispersion, and the other optically anisotropic layer is formed using a composition containing a discotic liquid crystal compound.In addition, such rod-shaped liquid crystal compounds and rod-shaped liquid crystal compounds with reverse wavelength dispersion include those described above as any liquid crystal compound contained in the light absorption anisotropic layer (particularly, reverse wavelength dispersion polymerizable liquid crystal compounds and forward wavelength dispersion polymerizable liquid crystal compounds).

[0114] In the optical film of the first embodiment of the present invention, when the optically anisotropic layer is a layer formed using a composition containing a liquid crystal compound, components other than the liquid crystal compound contained in the composition include components other than the dichroic material contained in the light absorption anisotropic layer described above. Furthermore, examples of methods for forming the optically anisotropic layer include a method in which a composition containing a liquid crystal compound is used to achieve a desired alignment state, and then the resulting alignment state is fixed by polymerization. While the polymerization conditions are not particularly limited, ultraviolet light is preferably used for polymerization by light irradiation. The irradiation dose is 10 mJ / cm. ２ ~50 J / cm ２ is preferred, and 20 mJ / cm ２ ~5 J / cm ２ More preferably, 30 mJ / cm ２ ~3 J / cm ２ is more preferably 50 to 1000 mJ / cm ２ In order to accelerate the polymerization reaction, the reaction may be carried out under heating conditions.

[0115] The thickness of the optically anisotropic layer is not particularly limited, but is preferably from 0.1 to 20 μm, more preferably from 0.5 to 15 μm, and even more preferably from 1 to 10 μm.

[0116] In the optical film of the first embodiment of the present invention, for the reason that the light blocking property for light incident from an oblique direction is improved, it is preferable that the two optically anisotropic layers are in direct contact with each other or are laminated via at least one of an adhesive layer, a pressure-sensitive adhesive layer, and an alignment film, which will be described later. Here, "laminated via at least one" means that when there is one of the adhesive layer, the pressure-sensitive adhesive layer, and the alignment film, they are laminated via only that one, but when there are two of the adhesive layer, the pressure-sensitive adhesive layer, and the alignment film (for example, the pressure-sensitive adhesive layer and the alignment film), they are laminated via only those two.

[0117] 1 , the angle between the in-plane slow axis direction of the first optically anisotropic layer 31 and the in-plane slow axis direction of the second optically anisotropic layer 32 is 60°. In the optical film of the first embodiment of the present invention, the angle between the in-plane slow axis direction of the first optically anisotropic layer and the in-plane slow axis direction of the second optically anisotropic layer is 55 to 80°, preferably greater than 55°, and more preferably 57° or greater. Furthermore, the angle is preferably 75° or less, more preferably 70° or less, and even more preferably 65° or less.

[0118] The optical film of the first embodiment of the present invention may have another optically anisotropic layer other than the first optically anisotropic layer and the second optically anisotropic layer. Examples of other optically anisotropic layers include a positive C plate. The optical film of the first embodiment of the present invention may have a positive C plate between the first optically anisotropic layer and the second optically anisotropic layer. Here, a positive C plate (positive C plate) is defined as follows: When the refractive index in the in-plane slow axis direction (the direction in which the in-plane refractive index is maximum) of the film is nx, the refractive index in the direction perpendicular to the in-plane slow axis is ny, and the refractive index in the thickness direction is nz, the positive C plate satisfies the relationship shown in formula (C1). The positive C plate exhibits a negative Rth value: nz>nx≒ny. The above "≒" encompasses not only the case where the two are completely identical, but also the case where the two are substantially identical. The term "substantially the same" includes, for example, the case where (nx-ny) x d (where d is the thickness of the film) is 0 to 10 nm, preferably 0 to 5 nm, in "nx≈ny".

[0119] The absolute value of the retardation in the thickness direction of the positive C plate at a wavelength of 550 nm is not particularly limited, but is preferably 10 to 400 nm, more preferably 100 to 180 nm.

[0120] The absolute value of the retardation in the thickness direction of the positive C plate at a wavelength of 650 nm is not particularly limited, but is preferably 10 to 500 nm, more preferably 120 to 220 nm, in terms of achieving better effects of the present invention.

[0121] The material constituting the positive C plate is not particularly limited, and may be a layer formed using a liquid crystal compound or a resin film.

[0122] [Support] The first embodiment of the optical film of the present invention may have a support. The type of support is not particularly limited, and known supports can be used. In particular, a transparent support is preferred. Note that the transparent support refers to a support having a visible light transmittance of 60% or more, and the transmittance is preferably 80% or more, and more preferably 90% or more.

[0123] Examples of the support include glass substrates and polymer films. Materials for the polymer film include cellulose-based polymers; acrylic polymers having acrylic acid ester polymers such as polymethyl methacrylate and lactone ring-containing polymers; thermoplastic norbornene-based polymers; polycarbonate-based polymers; polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate; styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymers; polyolefin-based polymers such as polyethylene, polypropylene, and ethylene-propylene copolymers; vinyl chloride-based polymers; amide-based polymers such as nylon and aromatic polyamides; imide-based polymers; sulfone-based polymers; polyethersulfone-based polymers; polyetheretherketone-based polymers; polyphenylene sulfide-based polymers; vinylidene chloride-based polymers; vinyl alcohol-based polymers; vinyl butyral-based polymers; arylate-based polymers; polyoxymethylene-based polymers; epoxy-based polymers; and polymers containing a mixture of these polymers. In addition, the support is preferably peelable.

[0124] [Alignment Film] In the first embodiment of the film of the present invention, when the above-mentioned light absorption anisotropic layer and optically anisotropic layer are layers formed using a composition containing a liquid crystal compound, an alignment film may be provided as an adjacent layer. Specific examples of the alignment film include layers of polyvinyl alcohol and polyimide, which may or may not have been subjected to a rubbing treatment; and photo-alignment films of polyvinyl cinnamate and azo dyes, which may or may not have been subjected to a polarized light exposure treatment. The thickness of the alignment film is preferably 0.01 to 10 μm, and more preferably 0.01 to 1 μm.

[0125] [Adhesive Layer] The first embodiment of the film of the present invention may have an adhesive layer. The adhesive layer is preferably a transparent, optically isotropic adhesive similar to those used in ordinary image display devices, and a pressure-sensitive adhesive is usually used.

[0126] In addition to the base material (adhesive), conductive particles, and optionally heat-expandable particles, the adhesive layer may contain appropriate additives such as crosslinking agents (e.g., isocyanate-based crosslinking agents, epoxy-based crosslinking agents, etc.), tackifiers (e.g., rosin derivative resins, polyterpene resins, petroleum resins, oil-soluble phenolic resins, etc.), plasticizers, fillers, antioxidants, surfactants, ultraviolet absorbers, light stabilizers, and antioxidants.

[0127] [Adhesive Layer] The optical film of the first embodiment of the present invention may have an adhesive layer. The adhesive layer exhibits adhesiveness by drying, reaction, etc. after lamination. A polyvinyl alcohol-based adhesive (PVA-based adhesive) exhibits adhesiveness by drying, making it possible to bond materials together.

[0128] Specific examples of curable adhesives that exhibit adhesive properties through a reaction include active energy ray-curable adhesives such as (meth)acrylate adhesives and cationic polymerization-curable adhesives. (Meth)acrylate refers to acrylate and / or methacrylate. Examples of curable components in (meth)acrylate adhesives include compounds having a (meth)acryloyl group and compounds having a vinyl group. Furthermore, compounds having an epoxy group or an oxetanyl group can also be used as cationic polymerization-curable adhesives. The epoxy group-containing compound is not particularly limited as long as it has at least two epoxy groups in its molecule, and various commonly known curable epoxy compounds can be used. Examples of preferred epoxy compounds include compounds having at least two epoxy groups and at least one aromatic ring in its molecule (aromatic epoxy compounds), and compounds having at least two epoxy groups in its molecule, at least one of which is formed between two adjacent carbon atoms constituting an alicyclic ring (alicyclic epoxy compounds). Among these, ultraviolet-curable adhesives that cure upon ultraviolet irradiation are preferred from the standpoint of thermal distortion resistance.

[0129] [Other Layers] The first embodiment of the film of the present invention may have layers (other layers) other than those described above. Examples of the other layers include a protective layer, an oxygen barrier layer, an ultraviolet absorbing layer, and a blue light absorbing layer.

[0130] A first embodiment of the optical film of the present invention has oblique transmittance anisotropy. Here, first, when the transmittances in a direction tilted at a polar angle of 60° from the transmittance central axis of the first optically absorptive anisotropic layer and the second optically absorptive anisotropic layer are measured over all azimuth angles, the maximum transmittance is defined as T1, and the azimuth angle at which T1 is exhibited is determined. Furthermore, the transmittance at an azimuth angle perpendicular to the azimuth at which T1 is exhibited is defined as T2. In this case, the ratio of T2 to T1 (T2 / T1) is preferably 60% or less, more preferably 50% or less, and even more preferably less than 40%. The lower limit of this ratio is, for example, 1% or more, and often 10% or more. For details of the method for measuring the transmittance, see the Examples section below.

[0131] Optical Film (Second Embodiment) A second embodiment of the optical film of the present invention comprises a first optically absorptive anisotropic layer, a third optically anisotropic layer, and a second optically absorptive anisotropic layer, in this order. The angle between the central transmittance axis of the first optically absorptive anisotropic layer and the normal to the surface of the first optically absorptive anisotropic layer is 0 to 45°. The angle between the central transmittance axis of the second optically absorptive anisotropic layer and the normal to the surface of the second optically absorptive anisotropic layer is 0 to 45°. The third optically anisotropic layer contains a liquid crystal compound that is twisted and aligned with the thickness direction of the third optically anisotropic layer as its helical axis, and the twist angle of the liquid crystal compound is 140 to 220°. Here, the product Δnd of the refractive index anisotropy Δn of the third optically anisotropic layer and the thickness d of the third optically anisotropic layer is 300 to 600 nm.

[0132] A second embodiment of the optical film of the present invention will be described with reference to the drawings. FIG. 5 is a schematic diagram showing an example of the second embodiment of the optical film of the present invention. The optical film 10b shown in FIG. 5 has a first optically absorptive anisotropic layer 22, a third optically anisotropic layer 33, and a second optically absorptive anisotropic layer 24, in this order. The first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24 each contain a dichroic material. In FIG. 5, the angles formed between the transmittance central axes (respectively indicated by the white arrows in FIG. 5) of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24 and the normal direction to the surface of each optically absorptive anisotropic layer are both 0°. In FIG. 5, the normal direction to the surface of the first optically absorptive anisotropic layer 22 is parallel to the z-axis direction, and the in-plane direction of each layer is parallel to the xy plane. The third optically anisotropic layer 33 contains rod-shaped liquid crystal compounds that are twisted and aligned with the thickness direction as the helical axis, and the twist angle of the liquid crystal compounds is 150°. That is, in the third optically anisotropic layer 33, the alignment direction (in-plane slow axis direction) of the rod-shaped liquid crystal compounds is twisted counterclockwise by 150° from the surface on the first optically absorptive anisotropic layer 22 side to the surface on the second optically absorptive anisotropic layer 24 side when viewed from the first optically absorptive anisotropic layer 22 side. The angle φ31 between the in-plane slow axis direction D31 and the x-axis direction at the surface on the first optically absorptive anisotropic layer 22 side of the third optically anisotropic layer 33 is 75°. The angle φ32 between the in-plane slow axis direction D32 and the x-axis direction at the surface on the second optically absorptive anisotropic layer 24 side of the third optically anisotropic layer 33 is 75°. The Δnd of the third optically anisotropic layer 33 is 450 nm.

[0133] This section explains that the optical film 10b shown in Fig. 5 exhibits a higher transmittance in an oblique direction at a predetermined azimuth angle than the transmittance in an oblique direction at an azimuth angle perpendicular to the predetermined azimuth angle (having oblique transmittance anisotropy). Specifically, this section explains that the optical film 10b shown in Fig. 5 exhibits a higher transmittance in a direction tilted by θ1 in the zx plane (the oblique direction DX in Fig. 5 ) from the z-axis direction (the transmittance central axis direction of the first optically absorptive anisotropic layer 22 and the transmittance central axis direction of the second optically absorptive anisotropic layer 24), and a lower transmittance in a direction tilted by θ2 in the yz plane from the z-axis direction (the oblique direction DY in Fig. 5 ). The absolute values ​​of the angles θ1 and θ2 are the same.

[0134] First, as explained in the optical film of the first embodiment, for light incident from the oblique direction DX, the dichroic material contained in the first optically absorptive anisotropic layer 22 tends to absorb components polarized in the x-axis direction in FIG. 5 , while easily transmit components polarized in the y-axis direction. When the third optically anisotropic layer 33 is divided at the center in the thickness direction, the liquid crystal compound alignment direction (in-plane slow axis direction) in the half adjacent to the first optically absorptive anisotropic layer 22 is rotated clockwise around the x-axis, while the liquid crystal compound alignment direction in the half adjacent to the second optically absorptive anisotropic layer 24 is rotated counterclockwise around the x-axis. Thus, the half adjacent to the first optically absorptive anisotropic layer 22 of the third optically anisotropic layer 33 can be considered as an optically anisotropic layer in which the in-plane slow axis direction is rotated clockwise around the x-axis. Furthermore, the half of the third optically anisotropic layer 33 facing the second optically absorptive anisotropic layer 24 can be considered an optically anisotropic layer in which the in-plane slow axis direction is rotated counterclockwise relative to the x-axis. Therefore, it can be said that light incident on the third optically anisotropic layer 33 from the oblique direction DY contains a large component polarized in the x-axis direction, and light exiting the third optically anisotropic layer 33 from the oblique direction DX is converted into light containing a large component polarized in the y-axis direction, as described in the first embodiment. Here, in the light incident from the oblique direction DY, the component polarized in the y-axis direction in FIG. 5 is easily absorbed by the dichroic material contained in the second optically absorptive anisotropic layer 24, and the component polarized in the x-axis direction is easily transmitted. As a result, the optical film 10b of the embodiment shown in FIG. 5 has low transmittance in the oblique direction DY.

[0135] As explained in the optical film of the first embodiment, the dichroic material contained in the first optically absorptive anisotropic layer 22 easily absorbs the component of light polarized in the y-axis direction in FIG. 5 , while easily transmits the component polarized in the x-axis direction. As mentioned above, the third optically anisotropic layer 33 is divided at the center position in the thickness direction. In this way, it can be said that light incident on the third optically anisotropic layer 33 from the oblique direction DX contains a large component polarized in the y-axis direction, and light exiting the third optically anisotropic layer 33 from the oblique direction DX is converted into light containing a large component polarized in the y-axis direction, as explained in the first embodiment. As described above, the optical film 10b of the embodiment shown in FIG. 5 has a high transmittance in the oblique direction DX. That is, since the transmittance in the oblique direction DX is higher than the transmittance in the oblique direction DY, the optical film 10b of the embodiment shown in FIG. 5 has oblique transmittance anisotropy.

[0136] It is also easily understood that the second embodiment of the optical film of the present invention has oblique transmittance anisotropy in embodiments other than those specifically described in Fig. 5, as in the specific embodiment described in Fig. 5. In the second embodiment of the optical film of the present invention, the transmittance is high in the direction of the transmittance central axes of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24. Furthermore, the direction in which the transmittance is high can be adjusted by adjusting the direction of the transmittance central axes of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24.

[0137] Each component of the optical film according to the second embodiment of the present invention will be described in detail below. The optical film according to the second embodiment differs from the optical film according to the first embodiment in terms of the optically anisotropic layer. The optically anisotropic layer (third optically anisotropic layer) will be described below. Other components, such as the optically absorbing anisotropic layer (first optically absorbing anisotropic layer 22 and second optically absorbing anisotropic layer 24), are similar to the optically absorbing anisotropic layer included in the optical film according to the first embodiment, and therefore will not be described here. The optical film according to the second embodiment may also include the components that may be included in the optical film according to the first embodiment. Furthermore, the optical film according to the second embodiment preferably exhibits the same oblique transmittance anisotropy properties (the above-mentioned T2 / T1) as the optical film according to the first embodiment.

[0138] [Third Optically Anisotropic Layer] The optical film of the second embodiment of the present invention includes a third optically anisotropic layer between two light-absorption anisotropic layers. The third optically anisotropic layer contains a liquid crystal compound that is twistedly aligned with its thickness direction as its helical axis. Such twisted alignment with the thickness direction as its helical axis is also called "twist alignment." A layer containing a twist-aligned liquid crystal compound is also called a "twist layer." The third optically anisotropic layer is preferably an optically anisotropic layer in which the alignment direction of the liquid crystal compound is fixed. The "fixed" state refers to a state in which the alignment of the liquid crystal compound is maintained. Specifically, the layer preferably has no fluidity and can stably maintain the fixed alignment without any change in the alignment due to an external field or external force, usually within a temperature range of 0 to 50°C, or, under more severe conditions, within a temperature range of -30 to 70°C.

[0139] Liquid crystal compounds can generally be classified into rod-shaped and discotic types based on their shape. Each type can further be divided into low-molecular-weight and high-molecular-weight types. Specific examples and preferred aspects of the liquid crystal compounds are the same as those described in the first embodiment, and therefore will not be described here.

[0140] Here, an example of a method for forming an optically anisotropic layer containing a twisted liquid crystal compound is a method of forming the layer using a liquid crystal composition containing a liquid crystal compound and a chiral agent. A chiral agent refers to a compound that can induce twisted alignment in a liquid crystal compound. The ability of the chiral agent to induce twisted alignment (helix induction force) may or may not change upon irradiation with light. Furthermore, the direction of the helix induction force is not particularly limited. Furthermore, the chiral agent may or may not exhibit liquid crystallinity.

[0141] Chiral agents (photoreactive chiral agents) whose helical twisting power changes upon irradiation with light include compounds having a chiral moiety and a photoreactive moiety whose structure changes upon irradiation with light, such as compounds that significantly change the twisting power of a liquid crystal compound depending on the amount of irradiation. Examples of photoreactive moieties whose structure changes upon irradiation with light include photochromic compounds (Kingo Uchida, Masahiro Irie, Chemical Industry, Vol. 64, p. 640, 1999; Kingo Uchida, Masahiro Irie, Fine Chemical, Vol. 28(9), p. 15, 1999). The structural change refers to decomposition, addition reaction, isomerization, racemization, [2+2] photocyclization, dimerization, and the like, which occur upon irradiation of the photoreactive moiety with light, and the structural change may be irreversible. Examples of chiral moieties include the asymmetric carbons described in Hiroyuki Nodaira, Chemistry Review, No. 22, Chemistry of Liquid Crystals, p. 73, 1994. Two or more of the above chiral agents may be used simultaneously, and a photoreactive chiral agent and a non-photoreactive chiral agent may be used in combination.

[0142] The twist angle of the liquid crystal compound in the third optically anisotropic layer is 140 to 220°, preferably more than 140°, and more preferably 145° or more. The twist angle is preferably 200° or less, and more preferably 180° or less. The twist angle can be adjusted by the type of chiral dopant contained in the liquid crystal composition, the amount of the chiral dopant, and the like.

[0143] In the third optically anisotropic layer 33 shown in FIG. 5, the layer is twisted counterclockwise when viewed from the first optically absorptive anisotropic layer 22 side, but it may be twisted clockwise.

[0144] In addition, the third optically anisotropic layer has a product Δnd of the refractive index anisotropy Δn and the thickness d of 300 to 600 nm. Δnd of the third optically anisotropic layer is preferably 350 nm or more, more preferably 400 nm or more. Δnd is preferably 550 nm or less, more preferably 500 nm or less. The value of Δnd can be adjusted by the type of liquid crystal compound used to form the third optically anisotropic layer and the thickness of the third optically anisotropic layer.

[0145] Although the above description has focused on the third optically anisotropic layer being an optically anisotropic layer in which the alignment direction of the liquid crystal compound is fixed, the alignment direction of the liquid crystal compound in the third optically anisotropic layer may not be fixed. For example, the third optically anisotropic layer may be a liquid crystal cell in which the alignment direction of the liquid crystal compound can be changed so as to include a liquid crystal compound with a twisted alignment. Examples of liquid crystal cells applicable to the third optically anisotropic layer include twisted nematic (TN) liquid crystal cells. In TN liquid crystal cells, when no voltage is applied, the rod-shaped liquid crystal molecules described below are substantially horizontally aligned and further twisted along the thickness direction (twisted alignment). TN liquid crystal cells are most commonly used as color TFT (Thin Film Transistor) liquid crystal displays and are described in numerous literature. In a TN liquid crystal cell used as the third optically anisotropic layer, the twist angle of the liquid crystal compound is 140 to 220° when no voltage is applied, and Δnd is 300 to 600 nm. The preferred ranges of the twist angle and Δnd of the liquid crystal compound are as described above.

[0146] The thickness of the third optically anisotropic layer is preferably from 0.1 to 20 μm, more preferably from 0.5 to 15 μm, and even more preferably from 1 to 10 μm.

[0147] Optical Film (Third Embodiment) A third embodiment of the optical film of the present invention comprises a first optically absorptive anisotropic layer, a fourth optically anisotropic layer, a fifth optically anisotropic layer, a sixth optically anisotropic layer, and a second optically absorptive anisotropic layer, in this order. The angle between the central transmittance axis of the first optically absorptive anisotropic layer and the normal to the surface of the first optically absorptive anisotropic layer is 0 to 45°. The angle between the central transmittance axis of the second optically absorptive anisotropic layer and the normal to the surface of the second optically absorptive anisotropic layer is 0 to 45°. Furthermore, the in-plane retardation of the fourth optically anisotropic layer at a wavelength of 550 nm is 100 to 250 nm, and the in-plane retardation of the fifth optically anisotropic layer at a wavelength of 550 nm is 100 to 250 nm. Here, the angle formed between the in-plane slow axis of the fourth optically anisotropic layer and the in-plane slow axis of the fifth optically anisotropic layer is 20 to 55°. In addition, the sixth optically anisotropic layer contains a liquid crystal compound that is twisted and aligned with the thickness direction of the sixth optically anisotropic layer as its helical axis, and the twist angle of the liquid crystal compound is 35 to 360°. Here, the product Δnd of the refractive index anisotropy Δn of the sixth optically anisotropic layer and the thickness d of the sixth optically anisotropic layer is 300 to 600 nm.

[0148] A third embodiment of the optical film of the present invention will be described with reference to the drawings. Fig. 6 is a schematic diagram showing an example of the third embodiment of the optical film of the present invention, and Fig. 7 is a diagram showing the azimuthal relationship of the in-plane slow axis direction when observed from the z-axis direction in Fig. 6. The optical film 10c shown in Fig. 6 has a first optically absorptive anisotropic layer 22, a fourth optically anisotropic layer 34, a fifth optically anisotropic layer 35, a sixth optically anisotropic layer 36, and a second optically absorptive anisotropic layer 24, in this order. The first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24 each contain a dichroic material. In Fig. 6, the angles formed between the transmittance central axes (corresponding to the hollow arrows in Fig. 6) of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24 and the normal direction to the surface of each optically absorptive anisotropic layer are both 0°. In Fig. 6, the normal to the surface of the first optically absorptive anisotropic layer 22 is parallel to the z-axis direction, and the in-plane directions of each layer are parallel to the xy plane. The in-plane retardation of each of the fourth optically anisotropic layer 34 and the fifth optically anisotropic layer 35 at a wavelength of 550 nm is 140 nm. In Fig. 6, the angle formed by the in-plane slow axis direction D4 of the fourth optically anisotropic layer 34 and the in-plane slow axis direction D5 of the fifth optically anisotropic layer 35 is φ45 shown in Fig. 7, where φ45 is 45°. The angle φ4 formed by the in-plane slow axis direction D4 and the x-axis direction is 10°, and the angle φ5 formed by the in-plane slow axis direction D5 and the x-axis direction is 55°.

[0149] The sixth optically anisotropic layer 36 shown in Fig. 6 contains rod-shaped liquid crystal compounds that are twisted and aligned with the thickness direction as the helical axis, and the twist angle of the liquid crystal compounds is 330°. That is, in the sixth optically anisotropic layer 36, the alignment direction (in-plane slow axis direction) of the rod-shaped liquid crystal compounds is twisted by 330° clockwise from the surface on the first optically absorptive anisotropic layer 22 side toward the surface on the second optically absorptive anisotropic layer 24 side, when viewed from the first optically absorptive anisotropic layer 22 side. The angle φ61 between the in-plane slow axis direction D61 and the x-axis direction at the surface on the first optically absorptive anisotropic layer 22 side of the sixth optically anisotropic layer 36 is 30°. The angle φ62 between the in-plane slow axis direction D62 and the x-axis direction at the surface on the second optically absorptive anisotropic layer 24 side of the sixth optically anisotropic layer 36 is 60°. The Δnd of the sixth optically anisotropic layer 36 is 500 nm.

[0150] In the optical film 10c shown in Fig. 6, the transmittance in an oblique direction at a predetermined azimuth angle is higher than the transmittance in an oblique direction at an azimuth angle perpendicular to the predetermined azimuth angle (oblique transmittance anisotropy is exhibited). That is, in the optical film 10c shown in Fig. 6, the transmittance is high in a direction tilted by θ1 in the zx plane from the z-axis direction (the transmittance central axis direction of the first optically absorptive anisotropic layer 22 and the transmittance central axis direction of the second optically absorptive anisotropic layer 24) (oblique direction DX in Fig. 6), and the transmittance is low in a direction tilted by θ2 in the yz plane from the z-axis direction (oblique direction DY in Fig. 6). Note that the absolute values ​​of the angles θ1 and θ2 are the same.

[0151] For light incident from the oblique direction DY, the dichroic material contained in the first optically absorptive anisotropic layer 22 tends to absorb components polarized in the y-axis direction in FIG. 6 , while easily transmitting components polarized in the x-axis direction. Thus, the fourth optically anisotropic layer 34 is primarily polarized in the x-axis direction and enters the fourth optically anisotropic layer 34 from the oblique direction DY, undergoes polarization conversion, and exits the fourth optically anisotropic layer 34. The light exiting the fourth optically anisotropic layer 34 enters the fifth optically anisotropic layer 35 from the oblique direction DY, undergoes polarization conversion, and exits the fifth optically anisotropic layer 35. The light exiting the fifth optically anisotropic layer 35 enters the sixth optically anisotropic layer 36, undergoes polarization conversion, and exits the sixth optically anisotropic layer 36. The light exiting the sixth optically anisotropic layer 36 enters the second optically absorptive anisotropic layer 24. The above polarization conversion will be explained using a projection diagram of a Poincaré sphere.

[0152] 8 is a diagram illustrating the polarization conversion of light incident from the oblique direction DY shown in FIG. 6 using a projection diagram of the Poincare sphere. The projection diagram of the Poincare sphere shown in FIG. ３ As described above, the light from the oblique direction DY that has passed through the first optically absorptive anisotropic layer 22 is mainly polarized in the x-axis direction. １The light represented by point P1c on the Poincaré sphere is incident on the fourth optically anisotropic layer 34 from the oblique direction DY. At this time, the in-plane slow axis direction D4 has a φ4 of 10° (see FIG. 7 ), and the in-plane retardation of the fourth optically anisotropic layer 34 is 140 nm, which is approximately a quarter wavelength of 550 nm. Therefore, when the light from point P1c on the Poincaré sphere enters the fourth optically anisotropic layer 34 from the oblique direction DY, it is converted by the fourth optically anisotropic layer 34 into a polarization state represented by point P2c on the southern hemisphere of the Poincaré sphere, and then exits the fourth optically anisotropic layer 34.

[0153] Next, the light emitted from the fourth optically anisotropic layer 34 (point P2c on the Poincare sphere) is incident on the fifth optically anisotropic layer 35 from the oblique direction DY. At this time, the in-plane slow axis direction D5 is φ5=55° (see FIG. 7), and the in-plane retardation of the fifth optically anisotropic layer 35 is 140 nm, which is approximately ¼ wavelength of 550 nm. Therefore, when the point P2c on the Poincare sphere is incident on the fifth optically anisotropic layer 35 from the oblique direction DY, the fifth optically anisotropic layer 35 shifts the point P2c on the Poincare sphere to the S hemisphere of the southern hemisphere of the Poincare sphere. ３ The light is converted into a polarization state represented by point P3c near the axis and is emitted from the fifth optically anisotropic layer 35.

[0154] Next, the light emitted from the fifth optically anisotropic layer 35 (point P3c on the Poincaré sphere) is incident on the sixth optically anisotropic layer 36 from the oblique direction DY. At this time, the twist angle of the rod-shaped liquid crystal compound in the sixth optically anisotropic layer 36 is 330°, and Δnd is 500 nm. Generally, polarization conversion by a layer containing twistedly aligned rod-shaped liquid crystal compounds can be understood by the locus of a rolling cone. Circularly polarized light incident on the sixth optically anisotropic layer 36 is rotated by approximately 3 / 4 rotation clockwise, while undergoing polarization conversion that converts the circularly polarized light into linearly polarized light. Therefore, when point P3c on the Poincaré sphere is incident on the sixth optically anisotropic layer 36 from the oblique direction DY, point P4c (S １ The light is converted into a polarization state represented by the polarization axis (near the axis) and emerges from the sixth optically anisotropic layer 36 .

[0155] By the above polarization conversion, the light represented by point P1c is converted into linearly polarized light (point P4c) in a substantially orthogonal direction by the fourth optically anisotropic layer 34, the fifth optically anisotropic layer 35, and the sixth optically anisotropic layer 36. In other words, the component of light polarized in the x-axis direction that enters the first optically absorptive anisotropic layer 22 from the oblique direction DY and exits the first optically absorptive anisotropic layer 22 is polarization converted by the fourth optically anisotropic layer 34, the fifth optically anisotropic layer 35, and the sixth optically anisotropic layer 36, and is converted into a component polarized in the y-axis direction.

[0156] As described above, the light emitted in the oblique direction DY from the sixth optically anisotropic layer 36 contains components polarized in the y-axis direction. Regarding the light incident from the oblique direction DY, the components polarized in the y-axis direction in FIG. 6 are easily absorbed by the dichroic material contained in the second optically absorptive anisotropic layer 24, and the components polarized in the x-axis direction are easily transmitted. Therefore, the optical film 10c having the configuration shown in FIG. 6 has low transmittance in the oblique direction DY.

[0157] On the other hand, for light incident from the oblique direction DX, the component polarized in the x-axis direction in FIG. 6 is easily absorbed by the dichroic material contained in the first optically absorptive anisotropic layer 22, and the component polarized in the y-axis direction is easily transmitted. Thus, the component polarized in the y-axis direction is mainly incident on the fourth optically anisotropic layer 34 from the oblique direction DX, undergoes polarization conversion, and exits the fourth optically anisotropic layer 34. The light exiting the fourth optically anisotropic layer 34 is incident on the fifth optically anisotropic layer 35 from the oblique direction DX, undergoes polarization conversion, and exits the fifth optically anisotropic layer 35. The light exiting the fifth optically anisotropic layer 35 enters the sixth optically anisotropic layer 36, undergoes polarization conversion, and exits the sixth optically anisotropic layer 36. The light exiting the sixth optically anisotropic layer 36 enters the second optically absorptive anisotropic layer 24. The above polarization conversion will be explained using a projection diagram of the Poincare sphere.

[0158] 9 is a diagram illustrating the polarization conversion of light incident from the oblique direction DX shown in FIG. 6 using a projection diagram of the Poincare sphere. The projection diagram of the Poincare sphere shown in FIG. 9 is a diagram illustrating the polarization conversion of light incident from the oblique direction DX shown in FIG. 6 using a projection diagram of the Poincare sphere. ３As described above, the light from the oblique direction DX that has passed through the first optically absorptive anisotropic layer 22 is mainly polarized in the y-axis direction. １ The polarization state of the light represented by point P1d on the Poincaré sphere is represented by point P1d on the axis. The light represented by point P1d on the Poincaré sphere is incident on the fourth optically anisotropic layer 34 from the oblique direction DX. At this time, the in-plane slow axis direction D4 has a φ4 of 10° (see FIG. 7 ), and the in-plane retardation of the fourth optically anisotropic layer 34 is 140 nm, which is approximately ¼ wavelength of 550 nm. Therefore, when point P1d on the Poincaré sphere is incident on the fourth optically anisotropic layer 34 from the oblique direction DY, the light is converted by the fourth optically anisotropic layer 34 into a polarization state represented by point P2d on the northern hemisphere of the Poincaré sphere, and then exits the fourth optically anisotropic layer 34.

[0159] Next, the light emitted from the fourth optically anisotropic layer 34 (point P2d on the Poincare sphere) is incident on the fifth optically anisotropic layer 35 from the oblique direction DX. At this time, the in-plane slow axis direction D5 is φ5=55° (see FIG. 7), and the in-plane retardation of the fifth optically anisotropic layer 35 is 140 nm, which is approximately ¼ wavelength of 550 nm. Therefore, when point P2d on the Poincare sphere is incident on the fifth optically anisotropic layer 35 from the oblique direction DX, it is reflected by the fifth optically anisotropic layer 35 at a point S in the northern hemisphere of the Poincare sphere. ３ The light is converted into a polarization state represented by point P3d near the axis and is emitted from the fifth optically anisotropic layer 35.

[0160] Next, the light emitted from the fifth optically anisotropic layer 35 (point P3d on the Poincare sphere) is incident on the sixth optically anisotropic layer 36 from the oblique direction DX. At this time, the twist angle of the rod-shaped liquid crystal compound in the sixth optically anisotropic layer 36 is 330°, and Δnd is 500 nm. As described above, the circularly polarized light incident on the sixth optically anisotropic layer 36 is rotated by approximately 3 / 4 rotation clockwise, and undergoes polarization conversion that converts the circularly polarized light into linearly polarized light. Therefore, when point P3d on the Poincare sphere is incident on the sixth optically anisotropic layer 36 from the oblique direction DX, the sixth optically anisotropic layer 36 rotates the circularly polarized light to a point P4d (S １ The light is converted into a polarization state represented by the on-axis polarizer and emerges from the sixth optically anisotropic layer 36 .

[0161] By the above polarization conversion, the light represented by point P1d is converted into linearly polarized light (point P4d) parallel to the light represented by point P1d by the fourth optically anisotropic layer 34, the fifth optically anisotropic layer 35, and the sixth optically anisotropic layer 36. In other words, the component of light polarized in the y-axis direction that enters the first optically absorptive anisotropic layer 22 from the oblique direction DX and exits the first optically absorptive anisotropic layer 22 undergoes polarization conversion by the fourth optically anisotropic layer 34, the fifth optically anisotropic layer 35, and the sixth optically anisotropic layer 36, and is converted into light having a large component polarized in the y-axis direction.

[0162] As described above, the light emitted from the sixth optically anisotropic layer 36 in the oblique direction DX contains components polarized in the y-axis direction. Here, in the light incident from the oblique direction DX, the components polarized in the x-axis direction in FIG. 6 are easily absorbed by the dichroic material contained in the second optically absorptive anisotropic layer 24, and the components polarized in the y-axis direction are easily transmitted. As a result, the optical film 10c in the embodiment shown in FIG. 6 has a high transmittance in the oblique direction DX. That is, since the transmittance in the oblique direction DX is higher than the transmittance in the oblique direction DY, the optical film 10c in the embodiment shown in FIG. 6 has oblique transmittance anisotropy.

[0163] It is easily understood that the third embodiment of the optical film of the present invention has oblique transmittance anisotropy in embodiments other than those specifically described in Figure 6, as in the specific embodiment described in Figure 6. For example, in the embodiment described in Figure 6, the sixth optically anisotropic layer 36 has the orientation direction (in-plane slow axis direction) of the rod-shaped liquid crystal compound twisted by 330° clockwise from the surface on the first optically absorptive anisotropic layer 22 side to the surface on the second optically absorptive anisotropic layer 24 side, as viewed from the first optically absorptive anisotropic layer 22 side. Here, it is easily understood that if the twist direction is counterclockwise, the optical rotation direction described in Figures 8 and 9 is reversed, resulting in a low transmittance in the oblique direction DX and a low transmittance in the oblique direction DY. Furthermore, in the third embodiment of the optical film of the present invention, the transmittance is high in the direction of the transmittance central axes of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24. Furthermore, by adjusting the direction of the central transmittance axis of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24, it is possible to adjust the direction in which the transmittance increases.

[0164] The fourth optically anisotropic layer has an in-plane retardation of 100 to 250 nm, preferably 120 to 200 nm, and more preferably 130 to 150 nm, at a wavelength of 550 nm. The fifth optically anisotropic layer has an in-plane retardation of 100 to 250 nm, preferably 120 to 200 nm, and more preferably 130 to 150 nm, at a wavelength of 550 nm. The angle between the in-plane slow axis of the fourth optically anisotropic layer and the in-plane slow axis of the fifth optically anisotropic layer is 20 to 55°, preferably 30 to 50°, and more preferably 40 to 50°.

[0165] The sixth optically anisotropic layer contains a liquid crystal compound that is twisted and aligned with the thickness direction as the helical axis, and the twist angle of the liquid crystal compound is 35 to 360°. The twist angle is preferably 100° or more, more preferably 200° or more, and even more preferably 300° or more. The Δnd of the sixth optically anisotropic layer is 300 to 600 nm, preferably 400 to 575 nm, and more preferably 450 to 550 nm. The orientation direction of the liquid crystal compound on the surface of the sixth optically anisotropic layer facing the fifth optically anisotropic layer is preferably 60 to 120°, more preferably 80 to 100°, with respect to the in-plane slow axis direction of the fifth optically anisotropic layer.

[0166] Preferred aspects and manufacturing methods of the fourth and fifth optically anisotropic layers other than the in-plane retardation are the same as those of the first and second optically anisotropic layers described in the optical film of the first embodiment, and therefore will not be described here. Preferred aspects and manufacturing methods of the sixth optically anisotropic layer other than the twist angle and Δnd are the same as those of the third optically anisotropic layer described in the optical film of the second embodiment, and therefore will not be described here. The optical film of the third embodiment may also include the same configuration as that included in the optical film of the first embodiment. Furthermore, the optical film of the third embodiment preferably exhibits the same oblique transmittance anisotropy properties (the above-mentioned T2 / T1) as the optical film of the first embodiment.

[0167] Optical Film (Fourth Embodiment) A fourth embodiment of the optical film of the present invention comprises a first optically absorptive anisotropic layer, a seventh optically anisotropic layer, an eighth optically anisotropic layer, a ninth optically anisotropic layer, a tenth optically anisotropic layer, and a second optically absorptive anisotropic layer, in this order. The angle between the central transmittance axis of the first optically absorptive anisotropic layer and the normal to the surface of the first optically absorptive anisotropic layer is 0 to 45°. The angle between the central transmittance axis of the second optically absorptive anisotropic layer and the normal to the surface of the second optically absorptive anisotropic layer is 0 to 45°. Furthermore, the in-plane retardation of the seventh optically anisotropic layer at a wavelength of 550 nm is 100 to 250 nm, and the in-plane retardation of the eighth optically anisotropic layer at a wavelength of 550 nm is 100 to 250 nm. The angle between the in-plane slow axis of the seventh optically anisotropic layer and the in-plane slow axis of the eighth optically anisotropic layer is 20 to 55°. Furthermore, the absolute value of the thickness direction retardation of the ninth optically anisotropic layer at a wavelength of 550 nm is 100 to 300 nm. In addition, the tenth optically anisotropic layer contains a liquid crystal compound that is twisted and aligned with the thickness direction of the tenth optically anisotropic layer as its helical axis, and the twist angle of the liquid crystal compound is 35 to 360°. Here, the product Δnd of the refractive index anisotropy Δn of the tenth optically anisotropic layer and the thickness d of the tenth optically anisotropic layer is 300 to 600 nm.

[0168] A fourth embodiment of the optical film of the present invention will be described with reference to the drawings. Fig. 10 is a schematic diagram showing an example of the fourth embodiment of the optical film of the present invention, and Fig. 11 is a diagram showing the azimuthal relationship of the in-plane slow axis direction when observed from the z-axis direction in Fig. 10. The optical film 10d shown in Fig. 10 has, in this order, a first optically absorptive anisotropic layer 22, a seventh optically anisotropic layer 37, an eighth optically anisotropic layer 38, a ninth optically anisotropic layer 39, a tenth optically anisotropic layer 40, and a second optically absorptive anisotropic layer 24. The first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24 each contain a dichroic material. In Fig. 10, the angles formed between the central transmittance axes (corresponding to the hollow arrows in Fig. 10) of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24 and the normal direction to the surface of each optically absorptive anisotropic layer are both 0°. In Fig. 10, the normal to the surface of the first optically absorptive anisotropic layer 22 is parallel to the z-axis direction, and the in-plane directions of each layer are parallel to the xy plane. The in-plane retardation of the seventh optically anisotropic layer 37 and the eighth optically anisotropic layer 38 at a wavelength of 550 nm is 140 nm. In Fig. 10, the angle formed by the in-plane slow axis direction D7 of the seventh optically anisotropic layer 37 and the in-plane slow axis direction D8 of the eighth optically anisotropic layer 38 is φ78 shown in Fig. 11, and φ78 is 45°. The in-plane slow axis direction D7 is parallel to the x-axis direction, and the angle φ8 formed by the in-plane slow axis direction D8 and the x-axis direction is 45°.

[0169] The tenth optically anisotropic layer 40 shown in Figure 10 contains rod-shaped liquid crystal compounds that are twisted and aligned with the thickness direction as the helical axis, and the twist angle of the liquid crystal compounds is 315°. That is, in the tenth optically anisotropic layer 40, the alignment direction (in-plane slow axis direction) of the rod-shaped liquid crystal compounds is twisted by 315° clockwise from the surface on the first optically absorptive anisotropic layer 22 side to the surface on the second optically absorptive anisotropic layer 24 side, when viewed from the first optically absorptive anisotropic layer 22 side. The angle φ101 between the in-plane slow axis direction D101 and the x-axis direction at the surface on the first optically absorptive anisotropic layer 22 side of the tenth optically anisotropic layer 40 is 90°. The angle φ102 between the in-plane slow axis direction D102 and the x-axis direction at the surface on the second optically absorptive anisotropic layer 24 side of the tenth optically anisotropic layer 10 is 45°. The Δnd of the tenth optically anisotropic layer 40 is 450 nm.

[0170] In the optical film 10d shown in Fig. 10, the transmittance in an oblique direction at a predetermined azimuth angle is higher than the transmittance in an oblique direction at an azimuth angle perpendicular to the predetermined azimuth angle (oblique transmittance anisotropy is exhibited). That is, in the optical film 10d shown in Fig. 10, the transmittance is high in a direction tilted by θ1 in the zx plane (oblique direction DX in Fig. 10) from the z-axis direction (the transmittance central axis direction of the first optically absorptive anisotropic layer 22 and the transmittance central axis direction of the second optically absorptive anisotropic layer 24), and the transmittance is low in a direction tilted by θ2 in the yz plane from the z-axis direction (oblique direction DY in Fig. 10). Note that the absolute values ​​of the angles θ1 and θ2 are the same.

[0171] The dichroic material contained in the first optically absorptive anisotropic layer 22 tends to absorb components of light polarized in the y-axis direction in FIG. 10 , and to transmit components polarized in the x-axis direction. Thus, the light polarized in the x-axis direction is mainly incident on the seventh optically anisotropic layer 37 from the oblique direction DY, undergoes polarization conversion, and exits the seventh optically anisotropic layer 37. The light exiting the seventh optically anisotropic layer 37 enters the eighth optically anisotropic layer 38 from the oblique direction DY, undergoes polarization conversion, and exits the eighth optically anisotropic layer 38. The light exiting the eighth optically anisotropic layer 38 enters the ninth optically anisotropic layer 39, undergoes polarization conversion, and exits the ninth optically anisotropic layer 39. The light that has exited the ninth optically anisotropic layer 39 enters the tenth optically anisotropic layer 40, undergoes polarization conversion, and exits the tenth optically anisotropic layer 40. The light that has exited the tenth optically anisotropic layer 40 enters the second optically absorptive anisotropic layer 24. The above polarization conversion will be explained using a projection diagram of a Poincare sphere.

[0172] 12 is a diagram illustrating the polarization conversion of light incident from the oblique direction DY shown in FIG. 10 using a projection diagram of the Poincare sphere. The projection diagram of the Poincare sphere shown in FIG. 12 is a diagram illustrating the polarization conversion of light incident from the oblique direction DY shown in FIG. ３ As described above, the light from the oblique direction DY that has passed through the first optically absorptive anisotropic layer 22 is mainly polarized in the x-axis direction. １ The polarization state of the light represented by point P1e on the Poincaré sphere is represented by point P1e on the axis. The light represented by point P1e on the Poincaré sphere is incident on the seventh optically anisotropic layer 37 from the oblique direction DY. At this time, the in-plane slow axis direction D7 is parallel to the x-axis direction (see FIG. 11 ). Therefore, even when point P1e on the Poincaré sphere is incident on the seventh optically anisotropic layer 37 from the oblique direction DY, it exits the seventh optically anisotropic layer 37 with almost no change from the polarization state represented by point P1e on the Poincaré sphere.

[0173] Next, the light emitted from the seventh optically anisotropic layer 37 (point P1e on the Poincare sphere) is incident on the eighth optically anisotropic layer 38 from the oblique direction DY. At this time, the in-plane slow axis direction D8 is φ8=45° (see FIG. 11), and the in-plane retardation of the eighth optically anisotropic layer 38 is 140 nm, which is approximately ¼ wavelength of 550 nm. Therefore, when point P1e on the Poincare sphere is incident on the eighth optically anisotropic layer 38 from the oblique direction DY, it is shifted by the eighth optically anisotropic layer 38 to point P2e on the Poincare sphere (point P2e in the southern hemisphere). ３ The light is converted into a polarization state represented by the on-axis polarizer and emerges from the eighth optically anisotropic layer 38 .

[0174] Next, the light emitted from the eighth optically anisotropic layer 38 (point P2e on the Poincare sphere) is incident on the ninth optically anisotropic layer 39 from the oblique direction DY. At this time, the ninth optically anisotropic layer 39 has a retardation of 200 nm at a wavelength of 550 nm in the thickness direction, and generates a phase difference for the light incident from the oblique direction DY. That is, for light incident from the oblique direction DY, the ninth optically anisotropic layer 39 acts as an optically anisotropic layer having an in-plane slow axis in the x-axis direction. Therefore, when point P2e on the Poincare sphere is incident on the ninth optically anisotropic layer 39 from the oblique direction DY, it is shifted by the ninth optically anisotropic layer 39 to point P3e on the Poincare sphere (point S on the equator). ２ The light is converted into a polarization state represented by the on-axis polarizer and emerges from the ninth optically anisotropic layer 39 .

[0175] Next, the light emitted from the ninth optically anisotropic layer 39 (point P3e on the Poincare sphere) is incident on the tenth optically anisotropic layer 40 from the oblique direction DY. At this time, the twist angle of the rod-like liquid crystal compound in the tenth optically anisotropic layer 40 is 315° and Δnd is 450 nm, so that the linearly polarized light incident on the tenth optically anisotropic layer 40 undergoes polarization conversion in which the light is rotated clockwise by approximately 3 / 4 rotation near the equator of the Poincare sphere. Therefore, when point P3e on the Poincare sphere is incident on the tenth optically anisotropic layer 40 from the oblique direction DY, it is rotated by the tenth optically anisotropic layer 40 to point P4e (S １ The light is converted into a polarization state represented by the polarization axis (near the tenth axis) and emerges from the tenth optically anisotropic layer 40 .

[0176] As a result of the polarization conversion, the light represented by point P1e is converted into linearly polarized light (point P4e) in a substantially orthogonal direction by the seventh optically anisotropic layer 37, the eighth optically anisotropic layer 38, the ninth optically anisotropic layer 39, and the tenth optically anisotropic layer 40. In other words, the component of light polarized in the x-axis direction that enters the first optically absorptive anisotropic layer 22 from the oblique direction DY and exits the first optically absorptive anisotropic layer 22 is polarization converted by the seventh optically anisotropic layer 37, the eighth optically anisotropic layer 38, the ninth optically anisotropic layer 39, and the tenth optically anisotropic layer 40, and is converted into a component polarized in the y-axis direction.

[0177] As described above, the light emitted from the tenth optically anisotropic layer 10 in the oblique direction DY contains components polarized in the y-axis direction. In the second optically absorptive anisotropic layer 24, the components polarized in the y-axis direction in Fig. 10 are easily absorbed by the dichroic material contained in the second optically absorptive anisotropic layer 24, and the components polarized in the x-axis direction are easily transmitted. Therefore, the optical film 10d shown in Fig. 10 has low transmittance in the oblique direction DY.

[0178] On the other hand, for light incident from the oblique direction DX, the component polarized in the x-axis direction in FIG. 6 is easily absorbed by the dichroic material contained in the first light absorption anisotropic layer 22, and the component polarized in the y-axis direction is easily transmitted. As a result, the component polarized in the y-axis direction is mainly incident on the seventh optically anisotropic layer 37 from the oblique direction DX, undergoes polarization conversion, and exits from the seventh optically anisotropic layer 37. The light exiting the seventh optically anisotropic layer 37 is incident on the eighth optically anisotropic layer 38 from the oblique direction DX, undergoes polarization conversion, and exits from the eighth optically anisotropic layer 38. The light exiting the eighth optically anisotropic layer 38 is incident on the ninth optically anisotropic layer 39, undergoes polarization conversion, and exits from the ninth optically anisotropic layer 39. The light that has exited the ninth optically anisotropic layer 39 enters the tenth optically anisotropic layer 40, undergoes polarization conversion, and exits the tenth optically anisotropic layer 40. The light that has exited the tenth optically anisotropic layer 40 enters the second optically absorptive anisotropic layer 24. The above polarization conversion will be explained using a projection diagram of a Poincare sphere.

[0179] 13 is a diagram illustrating the polarization conversion of light incident from the oblique direction DX shown in FIG. 10 using a projection diagram of the Poincare sphere. The projection diagram of the Poincare sphere shown in FIG. 13 is a diagram illustrating the polarization conversion of light incident from the oblique direction DX shown in FIG. ３ As described above, the light from the oblique direction DX that has passed through the first optically absorptive anisotropic layer 22 is mainly polarized in the y-axis direction. １ The polarization state of the light represented by the point P1f on the Poincaré sphere is represented by point P1f on the axis. The light represented by point P1f on the Poincaré sphere is incident on the seventh optically anisotropic layer 37 from the oblique direction DX. At this time, the in-plane slow axis direction D7 is perpendicular to the y-axis direction (see FIG. 11 ). Therefore, even when the light at point P1f on the Poincaré sphere is incident on the seventh optically anisotropic layer 37 from the oblique direction DX, it exits the seventh optically anisotropic layer 37 with almost no change from the polarization state represented by point P1f on the Poincaré sphere.

[0180] Next, the light emitted from the seventh optically anisotropic layer 37 (point P1f on the Poincare sphere) is incident on the eighth optically anisotropic layer 38 from the oblique direction DX. At this time, the in-plane slow axis direction D8 has a φ8 of 45° (see FIG. 11), and the in-plane retardation of the eighth optically anisotropic layer 38 is 140 nm, which is approximately a quarter wavelength of 550 nm. Therefore, when point P1f on the Poincare sphere is incident on the eighth optically anisotropic layer 38 from the oblique direction DX, it is shifted by the eighth optically anisotropic layer 38 to point P2f on the Poincare sphere (point P3f in the northern hemisphere). ３ The light is converted into a polarization state represented by the on-axis polarizer and emerges from the fifth optically anisotropic layer 35 .

[0181] Next, the light emitted from the eighth optically anisotropic layer 38 (point P2f on the Poincare sphere) is incident on the ninth optically anisotropic layer 39 from the oblique direction DX. At this time, the ninth optically anisotropic layer 39 has a retardation in the thickness direction of 200 nm at a wavelength of 550 nm, and generates a phase difference for the light incident from the oblique direction DX. That is, for light incident from the oblique direction DX, the ninth optically anisotropic layer 39 acts as an optically anisotropic layer having an in-plane slow axis in the y-axis direction. Therefore, when point P2f on the Poincare sphere is incident on the ninth optically anisotropic layer 39 from the oblique direction DX, it is shifted by the ninth optically anisotropic layer 39 to point P3f on the Poincare sphere (point S on the equator).２ The light is converted into a polarization state represented by the on-axis polarizer and emerges from the ninth optically anisotropic layer 39 .

[0182] Next, the light (point P3f on the Poincare sphere) emitted from the ninth optically anisotropic layer 39 is incident on the tenth optically anisotropic layer 40 from the oblique direction DX. At this time, the twist angle of the rod-like liquid crystal compound in the tenth optically anisotropic layer 40 is 315° and Δnd is 450 nm, so that the linearly polarized light incident on the tenth optically anisotropic layer 40 undergoes polarization conversion in which the light is rotated clockwise by approximately 3 / 4 rotation near the equator of the Poincare sphere. Therefore, when point P3f on the Poincare sphere is incident on the tenth optically anisotropic layer 40 from the oblique direction DX, it is rotated by the tenth optically anisotropic layer 40 to point P4f (S １ The light is converted into a polarization state represented by the on-axis polarizer and emerges from the tenth optically anisotropic layer 40 .

[0183] Due to the polarization conversion, the light represented by point P1f is converted into linearly polarized light (point P4f) parallel to the light represented by point P1f by the seventh optically anisotropic layer 37, the eighth optically anisotropic layer 38, the ninth optically anisotropic layer 39, and the tenth optically anisotropic layer 40. In other words, the component of light polarized in the y-axis direction that enters the first optically absorptive anisotropic layer 22 from the oblique direction DX and exits the first optically absorptive anisotropic layer 22 undergoes polarization conversion by the seventh optically anisotropic layer 37, the eighth optically anisotropic layer 38, the ninth optically anisotropic layer 39, and the tenth optically anisotropic layer 40, and is converted into light having a large component polarized in the y-axis direction.

[0184] As described above, the light emitted from the tenth optically anisotropic layer 40 in the oblique direction DX contains components polarized in the y-axis direction. Here, in the light incident from the oblique direction DX, the components polarized in the x-axis direction in FIG. 10 are easily absorbed by the dichroic material contained in the second optically absorptive anisotropic layer 24, and the components polarized in the y-axis direction are easily transmitted. As a result, the optical film 10d of the embodiment shown in FIG. 10 has a high transmittance in the oblique direction DX. That is, since the transmittance in the oblique direction DX is higher than the transmittance in the oblique direction DY, the optical film 10d of the embodiment shown in FIG. 10 has oblique transmittance anisotropy.

[0185] It is easily understood that the fourth embodiment of the optical film of the present invention has oblique transmittance anisotropy in embodiments other than those specifically described in Figure 10, as in the specific embodiment described in Figure 10. For example, in the embodiment described in Figure 10, the orientation direction (in-plane slow axis direction) of the rod-shaped liquid crystal compound in the tenth optically anisotropic layer 40 is twisted clockwise by 315° from the surface on the first optically absorptive anisotropic layer 22 side to the surface on the second optically absorptive anisotropic layer 24 side, when viewed from the first optically absorptive anisotropic layer 22 side. Here, it is easily understood that if the twist direction is counterclockwise, the optical rotation direction described in Figures 12 and 13 is reversed, resulting in a low transmittance in the oblique direction DX and a low transmittance in the oblique direction DY. Note that in the fourth embodiment of the optical film of the present invention, the transmittance is high in the direction of the transmittance central axes of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24. Furthermore, by adjusting the direction of the central transmittance axis of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24, it is possible to adjust the direction in which the transmittance increases.

[0186] The seventh optically anisotropic layer has an in-plane retardation of 100 to 250 nm, preferably 120 to 200 nm, and more preferably 130 to 150 nm, at a wavelength of 550 nm. The eighth optically anisotropic layer has an in-plane retardation of 100 to 250 nm, preferably 120 to 200 nm, and more preferably 130 to 150 nm, at a wavelength of 550 nm. The angle between the in-plane slow axis of the seventh optically anisotropic layer and the in-plane slow axis of the eighth optically anisotropic layer is 20 to 55°, preferably 30 to 50°, and more preferably 40 to 50°.

[0187] The ninth optically anisotropic layer has an absolute value of retardation in the thickness direction at a wavelength of 550 nm of 100 to 300 nm, preferably 120 to 280 nm, and more preferably 150 to 250 nm. That is, the ninth optically anisotropic layer may be either a positive C plate or a negative C plate, with a negative C plate being preferred. Here, a negative C plate (negative C plate) is defined as follows: The refractive index in the in-plane slow axis direction (the direction in which the in-plane refractive index is maximum) of the film is nx, the refractive index in the direction perpendicular to the in-plane slow axis is ny, and the refractive index in the thickness direction is nz. The negative C plate has a positive Rth. Formula (C2) nz<nx≒ny. The above "≒" encompasses not only the case where the two are completely identical, but also the case where the two are substantially identical. The term "substantially the same" includes, for example, the case where (nx-ny) x d (where d is the thickness of the film) is 0 to 10 nm, preferably 0 to 5 nm, in "nx≈ny".

[0188] The material constituting the positive C plate or the negative C plate is not particularly limited, and may be a layer formed using a liquid crystal compound or a resin film. An example of the negative C plate is a layer containing a horizontally aligned discotic liquid crystal compound.

[0189] The tenth optically anisotropic layer contains a liquid crystal compound that is twisted and aligned with the thickness direction as the helical axis, and the twist angle of the liquid crystal compound is 35 to 360°. The twist angle is preferably 100° or more, more preferably 200° or more, and even more preferably 300° or more. The Δnd of the tenth optically anisotropic layer is 300 to 600 nm, preferably 400 to 575 nm, and more preferably 450 to 550 nm. The orientation direction of the liquid crystal compound on the surface of the tenth optically anisotropic layer facing the eighth optically anisotropic layer is preferably 15 to 75°, more preferably 30 to 60°, with respect to the in-plane slow axis direction of the eighth optically anisotropic layer.

[0190] The optical film of the fourth embodiment may further include a C plate as an eleventh optically anisotropic layer. The eleventh optically anisotropic layer may be a positive C plate (positive C plate) or a negative C plate (negative C plate), with a negative C plate being preferred. The eleventh optically anisotropic layer is a layer separate from the ninth optically anisotropic layer. In the optical film of the fourth embodiment, the eleventh optically anisotropic layer is preferably disposed between the seventh optically anisotropic layer and the eighth optically anisotropic layer. Preferred aspects of the eleventh optically anisotropic layer are the same as those of the ninth optically anisotropic layer.

[0191] Preferred aspects and manufacturing methods of the seventh and eighth optically anisotropic layers other than the in-plane retardation are the same as those of the first and second optically anisotropic layers described in the optical film of the first embodiment, and therefore will not be described here. Preferred aspects and manufacturing methods of the tenth optically anisotropic layer other than the twist angle and Δnd are the same as those of the third optically anisotropic layer described in the optical film of the second embodiment, and therefore will not be described here. The optical film of the fourth embodiment may also include the same configuration as that included in the optical film of the first embodiment. Furthermore, the optical film of the fourth embodiment preferably exhibits the same oblique transmittance anisotropy properties (the above-mentioned T2 / T1) as the optical film of the first embodiment.

[0192] <Head-Mounted Display> The optical film of the present invention (first to fourth embodiments) can be applied to various display devices. As described above, the optical film of the present invention has high transmittance in the direction of the transmittance central axes of the first optically absorptive anisotropic layer and the second optically absorptive anisotropic layer and has oblique transmittance anisotropy, and therefore can be used, for example, to control the viewing angle of a display device. Furthermore, it can reduce light emitted from the display device in an oblique direction at a predetermined azimuth angle and transmit light at an azimuth angle perpendicular to the predetermined azimuth.

[0193] Among these, a preferred display device is a head-mounted display. Examples of head-mounted displays include the above-mentioned AR glasses. When the optical film of the present invention is applied to AR glasses, the direction of the transmittance central axis of the first optically absorptive anisotropic layer and the second optically absorptive anisotropic layer is bright, and light from oblique directions can be absorbed. Furthermore, since the optical film of the present invention has oblique transmittance anisotropy, it is possible to narrow the field of view at a predetermined azimuth angle (e.g., up and down) and widen the field of view at an azimuth angle (e.g., left and right) perpendicular to the predetermined azimuth in AR glasses, etc. Here, it can be said that external light that causes the above-mentioned rainbow unevenness in AR glasses is usually incident on the AR glasses from above the user. When the optical film of the present invention is applied to AR glasses, it is possible to effectively block external light incident from above (above the user's head) with respect to the diffraction element provided in the AR glasses, while widening the user's field of view in the left and right directions.

[0194] Hereinafter, AR glasses (head-mounted displays) including the optical film of the present invention will be described with reference to the drawings. Note that the head-mounted displays including the optical film of the present invention are not limited to the embodiments shown below, and can be applied to various head-mounted displays.

[0195] FIG. 14 is a cross-sectional schematic diagram showing a portion of AR glasses (a head-mounted display of the present invention). Specifically, the AR glasses 100 shown in FIG. 14 include an optical device 60 and an image display element 72 that receives image light L1. The optical device 60 includes a light guide plate 62 and an incident diffraction element 64 and an exit diffraction element 66 that are disposed on the side of the light guide plate 62 opposite the image display element 72 side. The optical device 60 also includes an optical element 50 that includes a cover glass 52 and an optical film 10. In the optical element 50, the optical film 10 is disposed on the light guide plate 62 side. The optical film 10 is disposed at a distance from the incident diffraction element 64 and the exit diffraction element 66. The optical film 10 shown in FIG. 14 can be any of the first to fourth embodiments of the optical film of the present invention described above. Here, the direction toward the front of the paper in FIG. 14 corresponds to the user's height. In FIG. 14, the optical film 10 is applied so that the azimuth angle direction at which the transmittance of the optical film 10 in the oblique direction is low is parallel to the height direction of the user.

[0196] The arrangement position of the incident diffraction element 64 corresponds to the incident position of the image light L1 from the image display element 72. The arrangement position of the output diffraction element 66 corresponds to the output position of the image light L1 from the light guide plate 62, i.e., the position at which the user observes the image light L1. The incident diffraction element 64 diffracts the image light L1 that enters the light guide plate 62 from the image display element 72, into the light guide plate 62. The diffracted image light L1 travels in the in-plane direction of the light guide plate 62 while being totally reflected within the light guide plate 62. The output diffraction element 66 diffracts the light propagating within the light guide plate 62 toward the user.

[0197] The light guide plate 62 included in the optical device 60 is not particularly limited, and any conventional light guide plate used in image display devices, such as light guide plates used in various AR glasses and light guide plates used in backlight units of liquid crystal display devices, can be used.

[0198] The incident diffraction element 64 and the exit diffraction element 66 included in the optical device 60 are transmissive diffraction elements, and the scenery on the backside can be simultaneously viewed through the incident diffraction element 64 and the exit diffraction element 66. The transmissive diffraction element is not particularly limited, and known diffraction elements used in AR glasses, such as relief-type diffraction elements, diffraction elements using liquid crystal, and volume hologram diffraction elements, can be used. Note that at least one of the incident diffraction element 64 and the exit diffraction element 66 may be a reflective diffraction element.

[0199] The image display element 72 included in the head-mounted display of the present invention is not particularly limited, and various known image display elements (displays) used in various image display devices such as AR glasses can be used. Examples of the image display element 72 include a liquid crystal display, an organic electroluminescence display, a DLP (Digital Light Processing), a MEMS (Micro-Electro-Mechanical Systems) display, and a micro LED (Light Emitting Diode) display. Examples of liquid crystal displays include LCOS (Liquid Crystal On Silicon). The image display element 72 may display monochrome images, two-color images, or color images.

[0200] 14 may have an intermediate diffraction element in addition to the incident diffraction element 64 and the exit diffraction element 66. The intermediate diffraction element has the function of bending the traveling direction of the image light L1 introduced into the light guide plate by the incident diffraction element toward the direction in which the exit diffraction element 66 is disposed. Diffraction elements similar to the incident diffraction element 64 and the exit diffraction element 66 can be used as the intermediate diffraction element.

[0201] 14, the optical film 10 is disposed on the light guide plate 62 side of the optical element 50 included in the optical device 60, but the optical film 10 may be disposed on the side opposite the light guide plate 62 side of the optical element 50 included in the optical device 60. That is, the cover glass 52 (transparent support) in the optical element 50 may be disposed on the light guide plate 62 side. In addition, in the AR glasses 100 of the embodiment shown in FIG. 14, the optical film 10 is disposed apart from the incident diffraction element 64 and the exit diffraction element 66, but may be in direct contact with them or in contact with them via another layer.

[0202] Furthermore, since the optical film (optical film 10) of the present invention can suppress rainbow unevenness in AR glasses, rainbow unevenness is suppressed in the head-mounted display (AR glasses 100) of the present invention including the optical film of the present invention. Furthermore, the head-mounted display of the present invention including the optical film of the present invention widens the user's field of view in the left-right direction. In the optical device 60, the optical element 50 is preferably arranged so as to overlap at least the area corresponding to the portion where the incident diffraction element 64 and the exit diffraction element 66 are arranged on the light guide plate 62. By arranging the optical element 50 so as to overlap the above-mentioned area, external light is less likely to be incident on the incident diffraction element 64 and the exit diffraction element 66 from an oblique direction, and the occurrence of rainbow unevenness can be further suppressed.

[0203] The present invention will be described in more detail below with reference to examples. The materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the examples shown below.

[0204] Example 1 Preparation of Optical Film A1 Optical film A1 was prepared according to the following procedure.

[0205] (Formation of Alignment Film Layer) The following composition for forming an alignment film 1 was applied to the surface of a commercially available cellulose acylate film (manufactured by Fujifilm Corporation, product name Fujitac TG60UL) using a wire bar. The support on which the coating film was formed was dried with hot air at 140°C for 120 seconds to form an alignment film AL1, thereby obtaining an alignment film-coated cellulose acylate film 1. The thickness of the alignment film AL1 was 1 μm.

[0206] ------------------------------------------------------------------ Composition 1 for forming alignment film -------------------------------------------------- Polymer PA-1 (described below) 100.00 parts by mass Acid generator PAG-1 (described below) 8.25 parts by mass Stabilizer DIPEA (described below) 0.6 parts by mass Butyl acetate 1001.42 parts by mass Methyl ethyl ketone 250.36 parts by mass

[0207] Polymer PA-1 (wherein the numerical value for each repeating unit represents the content (% by mass) of each repeating unit relative to all repeating units)

[0208] Acid generator PAG-1

[0209] Stabilizer DIPEA

[0210] (Formation of Optically Absorbent Anisotropic Layer) The following composition P1 for forming an optically absorbent anisotropic layer was continuously applied onto the obtained cellulose acylate film 1 with an alignment layer using a wire bar, heated at 120°C for 60 seconds, and then cooled to room temperature (23°C). Next, the composition was heated at 80°C for 60 seconds and cooled again to room temperature. Thereafter, an LED lamp (center wavelength 365 nm) was used to illuminate the film from the normal direction to the film at an illuminance of 200 mW / cm. ２ The optically absorptive anisotropic layer was formed on the alignment film AL1 by irradiating the film for 2 seconds under the irradiation conditions of 1.8 μm. The thickness of the optically absorptive anisotropic layer was 1.8 μm.

[0211] 0.17 parts by mass of dichroic substance D-2 below; 1.13 parts by mass of dichroic substance D-3 below; 8.67 parts by mass of polymer liquid crystal compound P-1 below; 1.97 parts by mass of liquid crystal compound L-1 below; 0.20 parts by mass of IRGACURE OXE-02 (manufactured by BASF); 0.16 parts by mass of alignment agent E-1 below; 0.16 parts by mass of alignment agent E-2 below; 0.007 parts by mass of surfactant F-1 below; 78.17 parts by mass of cyclopentanone; 8.69 parts by mass of benzyl alcohol ----------------------------------------------------------------------------------

[0212] Dichroic substance D-1

[0213] Dichroic substance D-2

[0214] Dichroic substance D-3

[0215] Polymer liquid crystal compound P-1

[0216] Liquid crystal compound L-1 [a mixture of the following liquid crystal compounds (RA), (RB) and (RC) in a mass ratio of 84:14:2]

[0217] Orientation agent E-1

[0218] Orientation agent E-2

[0219] Surfactant F-1 (In the following formula, TMS represents a trimethylsilyl group.)

[0220] (Formation of Protective Layer B1) The following protective layer-forming composition B1 was continuously applied to the obtained optically absorptive anisotropic layer using a wire bar to form a coating film. The support on which the coating film was formed was then dried with hot air at 60°C for 60 seconds and then with hot air at 100°C for 120 seconds to form a protective layer B1, thereby producing an optically absorptive anisotropic film having an optically absorptive anisotropic layer. The thickness of the protective layer was 0.5 μm.

[0221] -------------------------------------------------- Protective layer forming composition B1 -------------------------------------------------- 3.80 parts by mass of modified polyvinyl alcohol PVA-1 shown below 0.20 parts by mass IRGACURE 2959 70 parts by mass Water 30 parts by mass Methanol --------------------------------------------------

[0222] Modified polyvinyl alcohol PVA-1

[0223] The azimuthal angle and polar angle of the central axis of transmittance of the prepared optically absorbing anisotropic film were determined by the following procedure. Using an AxoScan OPMF-2 (manufactured by Axometrics), the transmittance was measured while changing the azimuthal angle and polar angle at which light was incident on the optically absorbing anisotropic film, as described above, to determine the direction of the central axis of transmittance of the optically absorbing anisotropic film. The angle between the central axis of transmittance of the optically absorbing anisotropic film and the normal to the optically absorbing anisotropic film was 0°.

[0224] (Formation of Optically Anisotropic Layer 1) The following composition for alignment film 2 was continuously applied to one side of a 40 μm-thick cellulose acylate film (TAC substrate; manufactured by Fujifilm Corporation, TG40) using a #14 wire bar, and then dried with hot air at 60° C. for 60 seconds and then with hot air at 100° C. for 120 seconds.

[0225] ------------------------------------------------------------------ Alignment film composition 2 ------------------------------------------------------------------ Modified polyvinyl alcohol PVA-1 described above: 10 parts by mass Water: 308 parts by mass Methanol: 70 parts by mass Isopropanol: 29 parts by mass Photopolymerization initiator (Irgacure 2959, manufactured by BASF): 0.8 parts by mass

[0226] - Formation of Retardation Layer 1 - The prepared alignment film 2 was continuously subjected to a rubbing treatment. At this time, the longitudinal direction of the long film was parallel to the conveyance direction, and the angle between the longitudinal direction of the film and the rotation axis of the rubbing roller was 90° (the film width direction was 0°, the film longitudinal direction was 90°, and when observed from the alignment film side, the clockwise direction with the film width direction as the reference is represented as a positive value, so the rotation axis of the rubbing roller was 0°).

[0227] A retardation layer coating solution 1 containing a discotic liquid crystal compound of the following composition was continuously applied to the above-prepared alignment film 2 using a #5.0 wire bar to prepare a retardation layer 1. The film conveying speed (V) was 26 m / min. To dry the solvent in the coating solution and ripen the alignment of the discotic liquid crystal compound, the film was heated with 130°C hot air for 90 seconds, followed by 100°C hot air for 60 seconds, and then irradiated with UV at 80°C to fix the alignment of the liquid crystal compound. The Re at 550 nm of the retardation layer 1 was 270 nm. The average tilt angle of the discotic liquid crystal compound's discotic surface relative to the film plane was 90°, confirming that the discotic liquid crystal compound was aligned perpendicular to the film plane.

[0228] -------------------------------- Composition of retardation layer coating solution 1------------------------------------------------ 80 parts by mass of discotic liquid crystal-1 below 20 parts by mass of discotic liquid crystal-2 below 0.55 parts by mass of alignment film interface aligning agent-1 below 0.05 parts by mass of alignment film interface aligning agent-2 below 0.09 parts by mass of surfactant F-4 below 10 parts by mass of modified trimethylolpropane triacrylate 3.0 parts by mass of photopolymerization initiator (Irgacure 907, manufactured by BASF) 200 parts by mass of methyl ethyl ketone ------------------------------------------------

[0229] Discotic Liquid Crystal-1

[0230] Discotic Liquid Crystal-2

[0231] Alignment film interface alignment agent-1

[0232] Alignment film interface alignment agent-2

[0233] Surfactant F-4

[0234] The surface of the above-mentioned light-absorbing anisotropic film on which the protective layer was formed and the support surface of the above-mentioned optically anisotropic film 1 were bonded using a pressure-sensitive adhesive layer (Opteria (registered trademark) NCF-D692 (film thickness: 15 μm, manufactured by Lintec Corporation)). Furthermore, an optically anisotropic film 1 other than the bonded optically anisotropic film 1 was prepared, and the surface of the retardation layer 1 and the surface of the retardation layer 1 bonded by the above-mentioned procedure were bonded using the pressure-sensitive adhesive layer. When the above-mentioned retardation layer 1 was bonded, the layers were bonded so that the angle between the in-plane slow axis of one retardation layer 1 and the in-plane slow axis of the other retardation layer 1 was 60°. Next, a light-absorbing anisotropic film other than the bonded light-absorbing anisotropic film was prepared, and the surface of the light-absorbing anisotropic film on which the protective layer was formed and the support surface of the already bonded optically anisotropic film 1 were bonded using the pressure-sensitive adhesive layer, thereby producing optical film A1. The prepared optical film A1 had "first optically absorptive anisotropic layer / first optically anisotropic layer (retardation layer 1) / second optically anisotropic layer (retardation layer 1) / second optically absorptive anisotropic layer" in this order.

[0235] Example 2 Preparation of Optically Anisotropic Film 2 An optically anisotropic film 2 including a retardation layer 2 was prepared in the same manner as in Example 1, except that in the preparation of the optically anisotropic layer 1 in Example 1, the retardation layer coating liquid 1 was changed to the retardation layer coating liquid 2 described below, and the coating amount of the retardation layer coating liquid 2 was adjusted so that the Re(550) value was 245 nm.

[0236] ------------------------------------------------ Composition of coating solution 2 for retardation layer ------------------------------------------------ 80 parts by mass of the following rod-shaped liquid crystal compound-1 20 parts by mass of the following rod-shaped liquid crystal compound-2 3 parts by mass of photopolymerization initiator (Irgacure 907, manufactured by BASF) 1 part by mass of sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.13 parts by mass of the following surfactant F-3 193 parts by mass of methyl ethyl ketone ------------------------------------------------

[0237] Rod-shaped liquid crystal compound-1

[0238] Rod-shaped liquid crystal compound-2

[0239] Surfactant F-3

[0240] [Preparation of Optical Film A2] Optical film A2 was prepared in the same manner as in Example 1, except that in the preparation of optical film A1 in Example 1, optically anisotropic film 1 was changed to optically anisotropic film 2. The layer structure of the prepared optical film A2 had "first optically absorptive anisotropic layer / first optically anisotropic layer (retardation layer 2) / second optically anisotropic layer (retardation layer 2) / second optically absorptive anisotropic layer" in this order.

[0241] Comparative Example 1 Preparation of Optical Film B1 Optical film B1 was prepared in the same manner as in Example 1, except that in the preparation of optical film A1 in Example 1, the retardation layers 1 were laminated such that the angle between the in-plane slow axis of one retardation layer 1 and the in-plane slow axis of the other retardation layer 1 was 45°. The layer structure of the prepared optical film B1 had a layer structure of "first optically absorptive anisotropic layer / first optically anisotropic layer (retardation layer 1) / second optically anisotropic layer (retardation layer 1) / second optically absorptive anisotropic layer" in this order.

[0242] Example 3 Preparation of Optically Anisotropic Film 3 A release support was prepared by rubbing the surface of a 75 μm PET film (manufactured by Fujifilm Corporation). The following twist layer coating solution 1 was applied to the rubbed surface of the prepared release support using a bar coater so that the resulting coating film had a thickness of 2.8 μm, forming a coating film. The coating film was then heated and aged for 90 seconds at a surface temperature of 60° C., and then irradiated with 300 mJ / cm at 100° C. ２The orientation of the liquid crystal compound was fixed by irradiating the film with ultraviolet light of 1000 nm to form a twist layer 1, and an optically anisotropic film 3 was produced comprising the peelable support and the twist layer 1. In the obtained twist layer 1, the liquid crystal compound had a Δn of 0.16 and a Δnd of 450 nm. The twist layer 1 contained a liquid crystal compound that was twisted and aligned along a helical axis extending along the thickness direction. Analysis using an AxoScan OPMF-2 (manufactured by Axometrics) confirmed that the twist angle of the liquid crystal compound was 150°. The twist direction of the liquid crystal compound was clockwise from the front surface of the twist layer 1 toward the back surface.

[0243] ------------------------------------------------ Coating solution 1 for twist layer -------------------------------------------------- Methyl ethyl ketone 233 parts by mass Cyclohexanone 12 parts by mass Rod-shaped liquid crystal compound 201 described below 83 parts by mass Rod-shaped liquid crystal compound 202 described below 15 parts by mass Rod-shaped liquid crystal compound 203 described below 2 parts by mass Polyfunctional monomer A-TMMT (manufactured by Shin-Nakamura Chemical Co., Ltd.) 1 part by mass IRGACURE 819 (manufactured by BASF) 4 parts by mass Surfactant F-4 described below 0.05 parts by mass Surfactant F-5 described below 0.01 parts by mass Chiral agent described below 0.205 parts by mass --------------------------------------------------

[0244]

[0245]

[0246]

[0247] [Preparation of Optical Film A3] The surface of the optically absorbing anisotropic film on which the protective layer was formed was bonded to the surface of the twist layer 1 of the optically anisotropic film 3 using a pressure-sensitive adhesive layer (Opteria (registered trademark) NCF-D692 (film thickness: 15 μm, manufactured by Lintec Corporation)), and the releasable support of the optically anisotropic film 3 was peeled off. Next, a light-absorbing anisotropic film separate from the bonded light-absorbing anisotropic film was prepared, and the surface of the light-absorbing anisotropic film on which the protective layer was formed was bonded to the surface of the twist layer 1 bonded in the above-mentioned procedure using the pressure-sensitive adhesive layer, thereby preparing Optical Film A3. The layer structure of the prepared Optical Film A3 was "first light-absorbing anisotropic layer / third optically anisotropic layer (twist layer 1) / second light-absorbing anisotropic layer" in this order.

[0248] Comparative Example 2 Preparation of Optically Anisotropic Film 4 Optically anisotropic film 4 was prepared in the same manner as in Example 3, except that in the preparation of optically anisotropic layer 3 in Example 3, twist layer coating liquid 1 was changed to twist layer coating liquid 2 described below. In the obtained twist layer 2, the liquid crystal compound had a Δn of 0.16 and a Δnd of 450 nm. Furthermore, twist layer 2 contained a liquid crystal compound that was twisted and aligned along a helical axis extending along the thickness direction. Analysis using an AxoScan OPMF-2 (manufactured by Axometrics) confirmed that the twist angle of the helical liquid crystal compound was 90°.

[0249] ------------------------------------------------ Twist layer coating liquid 2 -------------------------------------------------- Methyl ethyl ketone 233 parts by mass Cyclohexanone 12 parts by mass Rod-shaped liquid crystal compound 201 83 parts by mass Rod-shaped liquid crystal compound 202 15 parts by mass Rod-shaped liquid crystal compound 203 2 parts by mass Polyfunctional monomer A-TMMT (manufactured by Shin-Nakamura Chemical Co., Ltd.) 1 part by mass IRGACURE 819 (manufactured by BASF) 4 parts by mass Surfactant F-4 0.05 parts by mass Surfactant F-5 0.01 part by mass Chiral agent 0.123 parts by mass

[0250] [Preparation of Optical Film B2] Optical film B2 was prepared in the same manner as in Example 3 for preparing optical film A3, except that optically anisotropic film 3 was replaced with optically anisotropic film 4. The layer structure of the prepared optical film B2 was "first optically absorptive anisotropic layer / third optically anisotropic layer (twist layer 2) / second optically absorptive anisotropic layer" in this order.

[0251] <Comparative Example 3> [Preparation of optically anisotropic film 5] An optically anisotropic film 5 including a twist layer 3 was prepared in the same manner as in Comparative Example 2, except that in the preparation of the optically anisotropic layer 4 of Comparative Example 2, the amount of coating liquid 2 for the twist layer was adjusted so that the Δnd value was 750 nm and the twist angle of the helical liquid crystal compound was 150°.

[0252] [Preparation of Optical Film B3] Optical film B3 was prepared in the same manner as in Example 3 for preparing optical film A3, except that optically anisotropic film 3 was replaced with optically anisotropic film 5. The layer structure of the prepared optical film B3 was "first optically absorptive anisotropic layer / third optically anisotropic layer (twist layer 3) / second optically absorptive anisotropic layer" in this order.

[0253] <Example 4> [Preparation of optically anisotropic film 6] In the preparation of optically anisotropic layer 3 in Example 3, twist layer coating liquid 1 was changed to twist layer coating liquid 3 described below, and the amount of twist layer coating liquid 3 applied was adjusted so that the Δnd value was 500 nm and the twist angle of the helical liquid crystal compound was 330°. An optically anisotropic film 6 including twist layer 4 was prepared in the same manner as in Example 3, except that

[0254] ------------------------------------------------ Twist layer coating liquid 3 -------------------------------------------------- Methyl ethyl ketone 233 parts by mass Cyclohexanone 12 parts by mass Rod-shaped liquid crystal compound 201 83 parts by mass Rod-shaped liquid crystal compound 202 15 parts by mass Rod-shaped liquid crystal compound 203 2 parts by mass Polyfunctional monomer A-TMMT (manufactured by Shin-Nakamura Chemical Co., Ltd.) 1 part by mass IRGACURE 819 (manufactured by BASF) 4 parts by mass Surfactant F-4 0.05 parts by mass Surfactant F-5 0.01 parts by mass Chiral agent 0.405 parts by mass

[0255] [Preparation of Optically Anisotropic Film 7] In the preparation of the optically anisotropic film 2 of Example 2, the coating liquid 2 for retardation layer was changed to the following coating liquid 3 for retardation layer, and the coating amount of the coating liquid 3 for retardation layer was adjusted so that the Re(550) value was 140 nm. An optically anisotropic film 7 including the retardation layer 3 was prepared in the same manner as in Example 2, except that

[0256] ------------------------------------------------ Composition of retardation layer coating solution 3------------------------------------------------ Rod-like liquid crystal compound-1 80 parts by mass Rod-like liquid crystal compound-2 20 parts by mass Photopolymerization initiator (Irgacure 907, manufactured by BASF) 3 parts by mass Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass Surfactant F-3 0.26 parts by mass Methyl ethyl ketone 193 parts by mass

[0257] [Preparation of Optical Film A4] The surface of the lightly absorptive anisotropic film on which the protective layer was formed was bonded to the surface of the twist layer 4 of the optically anisotropic film 6 using a pressure-sensitive adhesive layer (Opteria (registered trademark) NCF-D692 (film thickness: 15 μm, manufactured by Lintec Corporation)), and the releasable support of the optically anisotropic film 6 was peeled off. Furthermore, the support side of the optically anisotropic film 7 was bonded to the surface of the twist layer 4 bonded in the above procedure using the pressure-sensitive adhesive layer. Furthermore, an optically anisotropic film 7 separate from the bonded optically anisotropic film 7 was prepared, and the surface of the retardation layer 3 bonded in the above procedure was bonded to the surface of the retardation layer 3 using the pressure-sensitive adhesive layer. When the retardation layer 3 was bonded, the layers were bonded so that the angle between the in-plane slow axis of one retardation layer 3 and the in-plane slow axis of the other retardation layer 3 was 45°. Next, a light-absorbing anisotropic film different from the laminated light-absorbing anisotropic film was prepared, and the surface of the light-absorbing anisotropic film on which the protective layer had been formed was laminated to the support surface of the optically anisotropic film 7 laminated in the above-described procedure using the pressure-sensitive adhesive layer, thereby producing optical film A4. The layer structure of the prepared optical film A4 was "first light-absorbing anisotropic layer / fourth optically anisotropic layer / fifth optically anisotropic layer / sixth optically anisotropic layer (twist layer 4) / second light-absorbing anisotropic layer" in this order.

[0258] <Example 5> [Preparation of optically anisotropic film 8] In the preparation of optically anisotropic layer 6 in Example 4, twist layer coating liquid 3 was changed to twist layer coating liquid 4 described below, and the amount of twist layer coating liquid 4 applied was adjusted so that the Δnd value was 450 nm and the twist angle of the helical liquid crystal compound was 315°. An optically anisotropic film 8 including twist layer 5 was prepared in the same manner as in Example 3, except that

[0259] ------------------------------------------------ Twist layer coating solution 4 -------------------------------------------------- Methyl ethyl ketone 233 parts by mass Cyclohexanone 12 parts by mass Rod-shaped liquid crystal compound 201 83 parts by mass Rod-shaped liquid crystal compound 202 15 parts by mass Rod-shaped liquid crystal compound 203 2 parts by mass Polyfunctional monomer A-TMMT (manufactured by Shin-Nakamura Chemical Co., Ltd.) 1 part by mass IRGACURE 819 (manufactured by BASF) 4 parts by mass Surfactant F-4 0.05 part by mass Surfactant F-5 0.01 part by mass Chiral agent 0.430 parts by mass

[0260] [Preparation of Optically Anisotropic Film 9] The following retardation layer coating solution 4 was prepared, and a uniform solution was obtained. ------------------------------------------------ Composition of retardation layer coating solution 4------------------------------------------------ 80 parts by mass of discotic liquid crystal compound CA-1 below; 20 parts by mass of discotic liquid crystal compound CA-2 below; 5.6 parts by mass of discotic liquid crystal compound CB-1 below; 5.6 parts by mass of polymerizable monomer CS1 below; 0.2 parts by mass of polymer CC-1 below; 3 parts by mass of polymerization initiator (Irgacure 907, manufactured by BASF); 170 parts by mass of toluene; 73 parts by mass of methyl ethyl ketone.

[0261] Discotic Liquid Crystal Compound CA-1 (1,3,5-Substituted Benzene-Type Polymerizable Discotic Liquid Crystal Compound)

[0262] Discotic Liquid Crystal Compound CA-2 (1,3,5-Substituted Benzene-Type Polymerizable Discotic Liquid Crystal Compound)

[0263] Discotic liquid crystal compound CB-1 (polymerizable triphenylene-type discotic liquid crystal compound)

[0264] Polymerizable monomer CS1

[0265] Polymer CC-1 (hereinafter, copolymerization ratios in chemical structural formulas are shown in mass %)

[0266] As a support, a commercially available cellulose triacetate film (Fujitac ZRD40, manufactured by Fujifilm Corporation) was subjected to a saponification treatment and used. The retardation layer coating solution 4 was applied to the surface of the support, and the solvent was dried by a process of continuously heating from room temperature to 100°C. The coating film was then further heated in a drying zone at 100°C for approximately 90 seconds. After that, the temperature was lowered to 60°C, and the film was then dried under atmospheric pressure at 300 mJ / cm. ２ The coating film was cured by UV exposure to form a cured film. After allowing the cured film to cool to room temperature, the orientation state of the cured film was observed, and it was found that the discotic liquid crystal compound was horizontally aligned without any defects. The resulting laminate film of the cured film and the support had an Re of 3 nm and an Rth of 200 nm. The optical film was designated as an optically anisotropic film 9 including a retardation layer 4.

[0267] [Preparation of Optical Film A5] The surface of the aforementioned lightly absorptive anisotropic film on which the protective layer was formed was bonded to the surface of the aforementioned optically anisotropic film 8 on which the twist layer 5 was formed using a pressure-sensitive adhesive layer (Opteria (registered trademark) NCF-D692 (film thickness: 15 μm, manufactured by Lintec Corporation)), and the releasable support of the optically anisotropic film 8 was peeled off. Furthermore, the support side of the aforementioned optically anisotropic film 9 was bonded to the surface of the twist layer 5 bonded in the above procedure using the above pressure-sensitive adhesive layer. Next, the support side of the aforementioned optically anisotropic film 7 was bonded to the surface of the optically anisotropic film 9 on which the retardation layer 4 was formed using the above pressure-sensitive adhesive layer. Furthermore, an optically anisotropic film 7 other than the bonded optically anisotropic film 7 was prepared, and the surface on the retardation layer 3 side was bonded to the surface on the retardation layer 3 side bonded in the above procedure using the above pressure-sensitive adhesive layer. When the retardation layers were bonded, they were bonded so that the angle between the in-plane slow axis of one retardation layer 3 and the in-plane slow axis of the other retardation layer 3 was 45°. Next, a light-absorbing anisotropic film other than the bonded light-absorbing anisotropic film was prepared, and the surface of the light-absorbing anisotropic film on which the protective layer was formed was bonded to the support surface of the optically anisotropic film 7 bonded by the above procedure using the above-mentioned pressure-sensitive adhesive layer, thereby producing an optical film A5. The layer structure of the produced optical film A4 was "light-absorbing anisotropic layer / optically anisotropic layer (slow axis azimuth angle 0 °) / optically anisotropic layer (slow axis azimuth angle -45 °) / optically anisotropic layer (C plate) / tenth optically anisotropic layer (twist layer 5) / light-absorbing anisotropic layer" in this order.

[0268] Example 6 Preparation of Optically Anisotropic Film 10 An optically anisotropic film 10 including a retardation layer 5 was prepared in the same manner as in Example 5, except that in the preparation of the optically anisotropic layer 9 in Example 5, the coating amount of the retardation layer coating solution 4 was adjusted so that the Rth(550) value was 180 nm.

[0269] [Preparation of Optical Film A6] The surface of the lightly absorptive anisotropic film on which the protective layer was formed was bonded to the surface of the twist layer 5 of the optically anisotropic film 8 using a pressure-sensitive adhesive layer (Opteria (registered trademark) NCF-D692 (film thickness: 15 μm, manufactured by Lintec Corporation)), and the releasable support of the optically anisotropic film 8 was peeled off. Furthermore, the support side of the optically anisotropic film 9 was bonded to the surface of the twist layer 5 bonded in the above-mentioned procedure using the pressure-sensitive adhesive layer. Next, the support side of the optically anisotropic film 7 described above was bonded to the surface of the retardation layer 4 of the optically anisotropic film 9 bonded in the above-mentioned procedure using the pressure-sensitive adhesive layer. Next, the support side of the optically anisotropic film 10 described above was bonded to the surface of the retardation layer 3 of the optically anisotropic film 7 bonded in the above-mentioned procedure using the pressure-sensitive adhesive layer. Furthermore, another optically anisotropic film 7 was prepared in addition to the optically anisotropic film 7 already bonded, and the surface of the optically anisotropic film 7 on the side of the retardation layer 3 was bonded to the surface of the optically anisotropic film 10 on the side of the retardation layer 5 bonded in the above-described procedure using the above-described pressure-sensitive adhesive layer. When the above-described retardation layer 3 was bonded, the films were bonded so that the angle between the in-plane slow axis of one retardation layer 3 of the optically anisotropic film 7 and the in-plane slow axis of the other retardation layer 3 of the optically anisotropic film 7 was 45°. Next, another optically absorbing anisotropic film in addition to the bonded optically anisotropic film was prepared, and the surface of the optically absorbing anisotropic film on which the protective layer was formed was bonded to the support surface of the optically anisotropic film 7 bonded in the above-described procedure using the above-described pressure-sensitive adhesive layer, thereby producing optical film A5. The layer structure of the produced optical film A5 was "first optically absorptive anisotropic layer / seventh optically anisotropic layer (retardation layer 3) / eleventh optically anisotropic layer (retardation layer 5, negative C plate) / eighth optically anisotropic layer (retardation layer 3) / ninth optically anisotropic layer (retardation layer 4, negative C plate) / tenth optically anisotropic layer (twist layer 5) / lightly absorptive anisotropic layer" in this order.

[0270] <Evaluation of Optical Films> The transmittance of the optical films of Examples 1 to 6 and Comparative Examples 1 to 3 was evaluated by the following procedure. Using an AxoScan OPMF-2 (manufactured by Axometrics), the Mueller matrix at a wavelength of 550 nm was measured. Specifically, the polar angle, which is the angle with respect to the normal direction of the optical film surface, was fixed at 60°, and the azimuthal angle was changed in 5° increments from 0 to 360°, while the Mueller matrix at a wavelength of 550 nm was measured, and the transmittance of the optical film was derived. As a result, the transmittance in the direction with the highest transmittance was designated T1 (%). Furthermore, the transmittance in an orientation rotated 90° from the orientation corresponding to T1 was designated T2 (%). The results are shown in the table below.

[0271] <Evaluation of Optical Films Used to Improve Rainbow Unevenness in AR Glass> The optical films of Examples 1 to 6 and Comparative Examples 1 to 3 were evaluated in the following manner when used to improve rainbow unevenness in AR glass. The results are shown in the table below.

[0272] [Rainbow unevenness evaluation] In a bright room with ceiling lighting, AR glasses (Vuzix Blade 2 manufactured by Vuzix) with the optical films of the Examples and Comparative Examples placed in front of the glasses were worn, and the appearance of rainbow unevenness was evaluated according to the following criteria. From a practical standpoint, a rating of A is preferable. Note that when evaluating the optical films, the optical films were placed so that the direction perpendicular to the direction showing the highest transmittance coincided with the up-down direction of the AR glasses (the direction of the user's height). A: Rainbow unevenness is less visible compared to when the optical film is not used. B: The appearance of rainbow unevenness is almost the same compared to when the optical film is not used.

[0273] [Brightness in the Frontal Direction] With the AR glasses equipped with each optical film, which had been evaluated for rainbow unevenness, worn, brightness in the frontal direction was evaluated according to the following criteria. In practical terms, a rating of A is preferable. A: Compared to when no optical film is used, the darkness is hardly noticeable. B: Compared to when no optical film is used, the brightness is perceived as being darker.

[0274] [Brightness in the horizontal direction] The change in brightness when only the gaze was directed from the front to the left or right while wearing the AR glasses equipped with each optical film, for which the rainbow unevenness evaluation was performed, was evaluated according to the following criteria. In practice, a rating of A or B is preferable, with a rating of A being more preferable. A: The darkness is not noticeable when the gaze is directed to the left or right. B: The darkness feels a little dark when the gaze is directed to the left or right. C: The darkness feels dark when the gaze is directed to the left or right.

[0275] <Results> The configuration of the optical film of each Example and Comparative Example and the above evaluation results are shown in Tables 1 to 3. In Tables 1 to 3, the column for the slow axis of each optically anisotropic layer indicates the azimuthal angle in a counterclockwise direction, assuming that the azimuthal angle showing the maximum transmittance is 0°. Tables 1 to 3 also show the results of measuring the transmittance at a polar angle of 0° using the above method. In Tables 1 to 3, the column for "T2 / T1" indicates the ratio (%) of T2 (transmittance in the orthogonal direction) to T1 (maximum transmittance).

[0276]

[0277]

[0278]

[0279] From the results shown in Tables 1 to 3, it was confirmed that the optical films of each Example having a predetermined configuration have small values ​​in the "T2 / T1" column, and thus have oblique transmittance anisotropy. On the other hand, the optical films of each Comparative Example have large values ​​in the "T2 / T1" column compared to the optical films of each Example, and thus do not exhibit oblique transmittance anisotropy, or if they do, the degree of such anisotropy is small. From a comparison between Example 5 and Example 6, it was further confirmed that when an 11th optically anisotropic layer is provided between the 7th and 8th optically anisotropic layers, and the 11th optically anisotropic layer is a C plate (more preferably a negative C plate), the value in the "T2 / T1" column becomes smaller.

[0280] 10, 10a, 10b, 10c, 10d Optical film 22 First optically absorptive anisotropic layer 24 Second optically absorptive anisotropic layer 31 First optically anisotropic layer 32 Second optically anisotropic layer 33 Third optically anisotropic layer 34 Fourth optically anisotropic layer 35 Fifth optically anisotropic layer 36 Sixth optically anisotropic layer 37 Seventh optically anisotropic layer 38 Eighth optically anisotropic layer 39 Ninth optically anisotropic layer 40 Tenth optically anisotropic layer 50 Optical member 52 Cover glass 60 Optical device 62 Light guide plate 64 Incident diffraction element 66 Outgoing diffraction element 72 Image display element 100 AR glasses (head-mounted display)

Claims

1. An optical film having a first light absorption anisotropic layer, a first optical anisotropic layer, a second optical anisotropic layer, and a second light absorption anisotropic layer in this order, wherein an angle formed by a transmittance central axis of the first light absorption anisotropic layer and a normal direction of a surface of the first light absorption anisotropic layer is 0 to 45°, an angle formed by a transmittance central axis of the second light absorption anisotropic layer and a normal direction of a surface of the second light absorption anisotropic layer is 0 to 45°, an in-plane retardation of the first optical anisotropic layer at a wavelength of 550 nm is 220 to 320 nm, an in-plane retardation of the second optical anisotropic layer at a wavelength of 550 nm is 220 to 320 nm, and an angle formed by an in-plane slow axis of the first optical anisotropic layer and an in-plane slow axis of the second optical anisotropic layer is 55 to 80°.

2. An optical film having a first light absorption anisotropic layer, a third optical anisotropic layer, and a second light absorption anisotropic layer in this order, wherein an angle formed by a transmittance central axis of the first light absorption anisotropic layer and a normal direction of a surface of the first light absorption anisotropic layer is 0 to 45°, an angle formed by a transmittance central axis of the second light absorption anisotropic layer and a normal direction of a surface of the second light absorption anisotropic layer is 0 to 45°, the third optical anisotropic layer contains a twisted nematic liquid crystal compound having a thickness direction of the third optical anisotropic layer as a helical axis, a twist angle of the liquid crystal compound is 140 to 220°, and a product Δnd of a refractive index anisotropy Δn of the third optical anisotropic layer and a thickness d of the third optical anisotropic layer is 300 to 600 nm.

3. An optical film having, in this order, a first light absorption anisotropic layer, a fourth optical anisotropic layer, a fifth optical anisotropic layer, a sixth optical anisotropic layer, and a second light absorption anisotropic layer, wherein the angle formed by the transmittance central axis of the first light absorption anisotropic layer and the normal direction of the surface of the first light absorption anisotropic layer is 0 to 45°; the angle formed by the transmittance central axis of the second light absorption anisotropic layer and the normal direction of the surface of the second light absorption anisotropic layer is 0 to 45°; the in-plane retardation of the fourth optical anisotropic layer at a wavelength of 550 nm is 100 to 250 nm; the in-plane retardation of the fifth optical anisotropic layer at a wavelength of 550 nm is 100 to 250 nm; the angle formed by the in-plane slow axis of the fourth optical anisotropic layer and the in-plane slow axis of the fifth optical anisotropic layer is 20 to 55°; the sixth optical anisotropic layer contains a twisted nematic liquid crystal compound having the thickness direction of the sixth optical anisotropic layer as a helical axis; the twist angle of the liquid crystal compound is 35 to 360°; the product Δnd of the refractive index anisotropy Δn of the sixth optical anisotropic layer and the thickness d of the sixth optical anisotropic layer is 300 to 600 nm.

4. An optical film having, in this order, a first light absorption anisotropic layer, a seventh optical anisotropic layer, an eighth optical anisotropic layer, a ninth optical anisotropic layer, a tenth optical anisotropic layer, and a second light absorption anisotropic layer, wherein the angle formed by the transmittance central axis of the first light absorption anisotropic layer and the normal direction of the surface of the first light absorption anisotropic layer is 0 to 45°; the angle formed by the transmittance central axis of the second light absorption anisotropic layer and the normal direction of the surface of the second light absorption anisotropic layer is 0 to 45°; the in-plane retardation of the seventh optical anisotropic layer at a wavelength of 550 nm is 100 to 250 nm; the in-plane retardation of the eighth optical anisotropic layer at a wavelength of 550 nm is 100 to 250 nm; the angle formed by the in-plane slow axis of the seventh optical anisotropic layer and the in-plane slow axis of the eighth optical anisotropic layer is 20 to 55°; the absolute value of the retardation in the thickness direction of the ninth optical anisotropic layer at a wavelength of 550 nm is 100 to 300 nm; the tenth optical anisotropic layer contains a twisted nematic liquid crystal compound having the thickness direction of the tenth optical anisotropic layer as a helical axis; the twist angle of the liquid crystal compound is 35 to 360°; the product Δnd of the refractive index anisotropy Δn and the thickness d of the tenth optical anisotropic layer is 300 to 600 nm.

5. Further, the optical film according to claim 4, having an eleventh optical anisotropic layer between the seventh optical anisotropic layer and the eighth optical anisotropic layer, wherein the eleventh optical anisotropic layer is a C-plate.

6. A head-mounted display including the optical film according to any one of claims 1 to 5.

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