Optical film and head-mounted display

Abstract

The present invention addresses the problem of providing an optical film in which a change in hue is small when viewed from an oblique direction while the azimuth angle of view is changed. This optical film comprises a first light-absorbing anisotropic layer, at least one optically anisotropic layer, and a second light-absorbing anisotropic layer in the stated order, wherein 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°, and when the transmittance at a wavelength of 450 nm, a wavelength of 550 nm, and a wavelength of 650 nm is measured four times from a direction inclined by 60° with respect to the normal direction of the surfaces of the first light absorption anisotropic layer and the second light absorption anisotropic layer while changing the azimuth angle by 90°, the difference between the largest value of the average transmittance for each wavelength and the smallest value of the average transmittance for each wavelength is 10% or more at each azimuth angle.

Description

Optical film, head-mounted display

[0001] The present invention relates to an optical film. The present invention also relates to 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 perceive the external light as a rainbow-colored reflection, 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 relative 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 is particularly problematic when external light is incident from between 40° and 80° relative to the normal to the surface of the diffraction element. 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] A method for suppressing rainbow unevenness includes a method of disposing a film that suppresses external light from being incident at the above-mentioned angle relative to the normal to the surface of the diffraction element. An example of a film having such a function is 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. 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 to 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 to 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] The optical film described in Patent Document 1 transmits light in a predetermined direction but has difficulty transmitting light in directions tilted from the predetermined direction, and is therefore sometimes disposed between the optical film and a light source. When the optical film is used in AR glasses, external light can be the light source. The inventors of the present invention have studied the optical film described in Patent Document 1 and found that when viewed from an inclined direction, the color tone may change depending on the azimuth angle.

[0007] Therefore, an object of the present invention is to provide an optical film that exhibits minimal change in color when viewed from an oblique direction while changing the 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, in this order, a first optically absorptive anisotropic layer, at least one or more optically anisotropic layers, and a second optically absorptive anisotropic layer, 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°, and 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°, and the transmittance is measured by incident P-polarized light of wavelengths of 450 nm, 550 nm, and 650 nm from a direction tilted by 60° with respect to the normal direction to the surface of the first optically absorptive anisotropic layer, and the average transmittance T at a wavelength of 450 nm is measured four times while changing the azimuth angle by 90°. Ａ４５０ , average transmittance T at a wavelength of 550 nm Ａ５５０ , average transmittance T at a wavelength of 650 nm Ａ６５０ When the average transmittance T Ａ４５０ , the above average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ The largest value among these and the average transmittance T Ａ４５０ , the above average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ The difference between the average transmittance T at a wavelength of 450 nm and the smallest value among the above is 10% or more, and an operation of measuring the transmittance by incident P-polarized light of wavelengths of 450 nm, 550 nm, and 650 nm from a direction tilted by 60° with respect to the normal direction of the surface of the second optically absorptive anisotropic layer is repeated four times while changing the azimuth angle by 90°. Ｂ４５０ , average transmittance T at a wavelength of 550 nm Ｂ５５０ , average transmittance T at a wavelength of 650 nm Ｂ６５０ When the average transmittance T Ｂ４５０ , the above average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ The largest value among these and the average transmittance T Ｂ４５０ , the above average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ [2] The difference between the average transmittance T Ａ４５０ , the above average transmittance T Ａ５５０ and the average transmittance T Ａ６５０and the wavelength at which the average transmittance T Ｂ４５０ , the above average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ The wavelength showing the largest value among the average transmittances T Ａ４５０ , the above average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ and the wavelength at which the average transmittance T Ｂ４５０ , the above average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ [3] The optical film according to [1], wherein the wavelengths showing the smallest values ​​among [a] and [b] are the same. [3] The optical film according to [1] or [2], wherein the first optically absorptive anisotropic layer contains at least one or more dichroic substances, and when the first optically absorptive anisotropic layer contains only one dichroic substance or when the first optically absorptive anisotropic layer contains two or more dichroic substances, the content of the dichroic substance with the largest content is 90 mass% or more relative to the total mass of the dichroic substances in the first optically absorptive anisotropic layer, and the second optically absorptive anisotropic layer contains at least one or more dichroic substances, and when the second optically absorptive anisotropic layer contains only one dichroic substance or when the second optically absorptive anisotropic layer contains two or more dichroic substances, the content of the dichroic substance with the largest content is 90 mass% or more relative to the total mass of the dichroic substances in the second optically absorptive anisotropic layer. [4] The optical film according to any one of [1] to [3], comprising two of the optically anisotropic layers, wherein the optically anisotropic layers have an in-plane retardation of 170 to 220 nm at a wavelength of 550 nm. [5] A head-mounted display comprising the optical film according to any one of [1] to [4].

[0010] According to the present invention, an optical film can be provided that exhibits little change in color when viewed from an oblique direction while changing the azimuth angle.Furthermore, according to the present invention, a head-mounted display can be provided.

[0011] It is a schematic diagram showing an example of the optical film of the present invention. It is a diagram showing the azimuthal relationship of the in-plane slow axis when observed from the z-axis direction in Figure 1. It is a cross-sectional schematic diagram showing a part of AR glasses (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) 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. When a dichroic material is contained in the light absorption anisotropic layer, the transmittance central axis means the direction of the absorption axis of the dichroic material (the direction of the long axis of the molecule).

[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] <Optical Film> The optical film of the present invention comprises, in this order, a first optically absorptive anisotropic layer, at least one optically anisotropic layer, and a second optically absorptive anisotropic layer. 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°, and 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°. Furthermore, the transmittance was measured four times by incidenting P-polarized light of wavelengths of 450 nm, 550 nm, and 650 nm from a direction tilted by 60° with respect to the normal direction to the surface of the first optically absorptive anisotropic layer, changing the azimuth angle by 90°. The average transmittance T at a wavelength of 450 nm was measured. Ａ４５０ , average transmittance T at a wavelength of 550 nm Ａ５５０ , average transmittance T at a wavelength of 650 nm Ａ６５０ When the average transmittance T Ａ４５０ , the above average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ The largest value among these and the average transmittance T Ａ４５０, the above average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ The difference between the smallest value of the first maximum transmittance difference and the first maximum transmittance difference (hereinafter also referred to as "first maximum transmittance difference") is 10% or more. The transmittance is measured by irradiating P-polarized light of wavelengths of 450 nm, 550 nm, and 650 nm from a direction tilted by 60° with respect to the normal direction of the surface of the second optically absorptive anisotropic layer four times while changing the azimuth angle by 90°. Ｂ４５０ , average transmittance T at a wavelength of 550 nm Ｂ５５０ , average transmittance T at a wavelength of 650 nm Ｂ６５０ When the average transmittance T Ｂ４５０ , the above average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ The largest value among these and the average transmittance T Ｂ４５０ , the above average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ The difference between the smallest value of the two (hereinafter also referred to as the "second maximum transmittance difference") is 10% or more.

[0022] 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 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 10 shown in FIG. 1 has a first optically absorptive anisotropic layer 22, a first optically anisotropic layer 32, a second optically anisotropic layer 34, 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 white 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 32 and the second optically anisotropic layer 34 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 32 and the in-plane slow axis direction D2 of the second optically anisotropic layer 34 is φ12 shown in Fig. 2, and φ12 is 45°. The angle φ2 formed by the in-plane slow axis direction D2 and the x-axis direction is 45°.

[0023] When the optical film 10 is placed between the viewer and the light source and viewed from the z-axis direction in Figure 1, the transmittance central axes of the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24 are parallel to the z-axis direction, resulting in high transmittance in that direction and making light from the light source easily visible. Here, we will explain that transmittance decreases when the light from the light source is viewed from a direction tilted by θ1 in the zx plane (the oblique direction DX in Figure 1) and a direction tilted by θ2 in the yz plane (the oblique direction DY in Figure 1). In other words, we will explain that transmittance decreases when the light from the light source is viewed from a direction tilted from the z-axis direction. The absolute values ​​of the angles θ1 and θ2 are the same.

[0024] Light incident obliquely onto the second optically absorptive anisotropic layer 24 is likely to absorb P-polarized light, which is a polarization component vibrating in an in-plane direction that includes the incident direction of the incident light and is perpendicular to the surface of the second optically absorptive anisotropic layer 24. On the other hand, S-polarized light, which is a polarization component vibrating in a direction perpendicular to the plane of incidence, is likely to be transmitted. Similarly, with respect to light incident obliquely onto the first optically absorptive anisotropic layer 22, P-polarized light is likely to be absorbed, and S-polarized light is likely to be transmitted. Therefore, light incident on the second optically absorptive anisotropic layer 24 from the direction opposite the oblique direction DX and entering the second optically anisotropic layer 34 is likely to contain a large amount of S-polarized light vibrating in the y-axis direction in FIG. 1 . The S-polarized light component is converted into a P-polarized light component by the second optically absorptive anisotropic layer 24, and is therefore likely to be absorbed by the first optically absorptive anisotropic layer 22. Furthermore, light incident on the second optically absorptive anisotropic layer 24 from the direction opposite to the oblique direction DY and then entering the second optically anisotropic layer 34 tends to contain a large amount of S-polarized light, which vibrates in the x-axis direction in FIG. 1 . The S-polarized light component is converted into a P-polarized light component by the second optically absorptive anisotropic layer 24 and is therefore easily absorbed by the first optically absorptive anisotropic layer 22. From the above, when the light from the light source is viewed from the oblique direction DX in FIG. 1 and the oblique direction DY in FIG. 1 , the transmittance is low. Furthermore, when viewed from an oblique direction between the azimuth angles of the oblique directions DX and DY, the S-polarized light component is converted into a P-polarized light component by the first optically anisotropic layer 32, and therefore the transmittance is similarly low.

[0025] 1, it can be seen that the transmittance is low when light from the light source is viewed from a direction tilted from the z-axis direction. Furthermore, even when the angle between the central axis of transmittance and the normal to the surface of each optically absorptive anisotropic layer in the first optically absorptive anisotropic layer 22 and the second optically absorptive anisotropic layer 24 is not 0°, it can be seen that the transmittance is low based on the same principle as above when light from the light source is viewed from a direction tilted from the central axis of transmittance.

[0026] In the optical film 10 shown in FIG. 1 , the first maximum transmittance difference in the first optically absorptive anisotropic layer 22 is 10% or more, and the second maximum transmittance difference in the second optically absorptive anisotropic layer 24 is 10% or more. The mechanism by which the optical film 10 of the present invention exhibits minimal color change when the film is placed between a viewer and a light source and viewed from oblique directions while changing the azimuth angle is not entirely clear, but the present inventors speculate as follows. In the optical film 10, the transmittance of light incident from an oblique direction is reduced based on the above-described principle. The first optically anisotropic layer 32 and the second optically anisotropic layer 34 generally exhibit dispersion, and the perceived in-plane retardation changes depending on the wavelength of the incident light. Through research by the present inventors, it was discovered that the dispersion may cause color change depending on the azimuth angle at which the film is viewed from an oblique direction. Here, when the first maximum transmittance difference is 10% or more and the second maximum transmittance difference is 10% or more as described above, it is possible to adjust the color region in which a change in color occurs, and as a result, it is thought that the change in color will be smaller.

[0027] The optical film of the present invention is not limited to the embodiment shown in FIG. 1 and can be modified in various ways. For example, the optically anisotropic layer may be one layer or three or more layers. Other embodiments of the optically anisotropic layer can be appropriately applied to the embodiments described below. Furthermore, the first optically absorptive anisotropic layer and the second optically absorptive anisotropic layer can be appropriately applied to the embodiments described below. Each layer of the optical film of the present invention will be described in detail below, but unless a particular distinction is required for the purpose of explanation, the first optically absorptive anisotropic layer and the second optically absorptive anisotropic layer will be collectively referred to as the "optically absorptive anisotropic layer."

[0028] [Lightly Absorbent Anisotropic Layer] The optical film of the present invention includes two lightly absorptive anisotropic layers (a first lightly absorptive anisotropic layer and a second lightly absorptive anisotropic layer). In the lightly absorptive anisotropic layer, the angle between the central axis of transmittance of the lightly absorptive anisotropic layer and the normal direction to the surface of the lightly absorptive 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°. From the viewpoint of improving light transmittance, the central axes of transmittance of the two lightly absorptive anisotropic layers are preferably parallel. The surface of the lightly absorptive anisotropic layer corresponds to one of the two main surfaces perpendicular to the thickness direction of the lightly absorptive anisotropic layer. The main surface is the surface of the lightly absorptive anisotropic layer with the largest area.

[0029] As described above, the first optically absorptive anisotropic layer has the first maximum transmittance difference of 10% or more, and the second optically absorptive anisotropic layer has the second maximum transmittance difference of 10% or more. A method for calculating the first maximum transmittance difference will be described below.

[0030] When calculating the first maximum transmittance difference, first, P-polarized light with wavelengths of 450 nm, 550 nm, and 650 nm is incident on the first optically absorptive anisotropic layer from a direction tilted 60° relative to the normal to the surface of the layer, and the transmittance is measured four times, with the azimuth angle changed by 90°. That is, P-polarized light of each wavelength is incident on the first optically absorptive anisotropic layer at a polar angle of 60° from azimuth angles of 0°, 90°, 180°, and 270°, and the transmittance is measured. Note that P-polarized light refers to a polarized light component that vibrates in an in-plane direction that includes the direction of light incidence and the normal to the surface of the first optically absorptive anisotropic layer. The measurement may be performed by removing the first optically absorptive anisotropic layer from the optical film. The measurement can be performed using an AxoScan OPMF-2 (manufactured by Axometrics).

[0031] The above measurement was performed, and the arithmetic mean value of the transmittance when P-polarized light was incident from each azimuth angle was calculated for each measurement wavelength, and the average transmittance T Ａ４５０ , average transmittance T at a wavelength of 550 nm Ａ５５０ , average transmittance T at a wavelength of 650 nm Ａ６５０ Next, the average transmittance T Ａ４５０, the above average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ The largest value among these and the average transmittance T Ａ４５０ , the above average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ The difference between the smallest value and the first maximum transmittance difference is calculated and defined as the first maximum transmittance difference.

[0032] The second maximum transmittance difference is also measured in the same manner as the first maximum transmittance difference. Ｂ４５０ , the above average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ Next, the average transmittance T Ｂ４５０ , the above average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ The largest value among these and the average transmittance T Ｂ４５０ , the above average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ The difference between the smallest value and the second largest transmittance difference is calculated and used as the second largest transmittance difference.

[0033] The first maximum transmittance difference is 10% or more, and may be 15% or more, 20% or more, 30% or more, or 40% or more. The first maximum transmittance difference is often 80% or less, preferably 70% or less, and may be 60% or less. The second maximum transmittance difference is 10% or more, and may be 15% or more, 20% or more, 30% or more, or 40% or more. The second maximum transmittance difference is often 80% or less, preferably 70% or less, and may be 60% or less. The first maximum transmittance difference and the second maximum transmittance difference can be adjusted, for example, by the type of dichroic material contained in the light-absorption anisotropic layer, the content ratio of the dichroic material, the degree of orientation of the dichroic material, etc.

[0034] In addition, the average transmittance T Ａ４５０ , the above average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ and the wavelength at which the average transmittance T Ｂ４５０ , the above average transmittance T Ｂ５５０and the average transmittance T Ｂ６５０ It is also preferable that the wavelength at which the average transmittance T Ａ４５０ , average transmittance T Ａ５５０ and average transmittance T Ａ６５０ Among them, T Ａ６５０ is the largest value, and the average transmittance T Ｂ４５０ , average transmittance T Ｂ５５０ and average transmittance T Ｂ６５０ Among them, T Ｂ６５０ When the wavelengths at which the average transmittances of the first and second optically absorptive anisotropic layers are the same are the same, the wavelength is preferably 550 nm or 650 nm, and more preferably 650 nm.

[0035] Furthermore, the average transmittance T Ａ４５０ , the above average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ and the wavelength at which the average transmittance T Ｂ４５０ , the above average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ It is also preferable that the wavelength at which the average transmittance T Ａ４５０ , average transmittance T Ａ５５０ and average transmittance T Ａ６５０ Among them, T Ａ４５０ is the smallest value, and the average transmittance T Ｂ４５０ , average transmittance T Ｂ５５０ and average transmittance T Ｂ６５０ Among them, T Ｂ４５０ When the wavelengths at which the average transmittances of the first optically absorptive anisotropic layer and the second optically absorptive anisotropic layer are smallest are the same, the wavelength is preferably 450 nm or 550 nm, and more preferably 450 nm.

[0036] In the first optically absorptive anisotropic layer and the second optically absorptive anisotropic layer, the wavelength at which the average transmittance is greatest can be adjusted, for example, by the type of dichroic material contained in the optically absorptive anisotropic layer, the content ratio of the dichroic material, etc. In the first optically absorptive anisotropic layer and the second optically absorptive anisotropic layer, the wavelength at which the average transmittance is least can be adjusted, for example, by the type of dichroic material contained in the optically absorptive anisotropic layer, the content ratio of the dichroic material, the degree of orientation of the dichroic material, etc.

[0037] 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.

[0038] (Dichroic Material) In the present invention, the dichroic material refers to a dye whose absorbance varies depending on the direction. The dichroic material may or may not exhibit liquid crystallinity.

[0039] 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.

[0040] 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.

[0041] In the present invention, 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. Note that in the present invention, as long as the requirements for the first maximum transmittance difference and the second maximum transmittance difference described above are satisfied, at least one dye compound selected from the group consisting of 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, 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 may be used. In the present invention, two or more or three or more dichroic azo dye compounds may be used in combination, but it is also preferable to use only one dichroic azo dye compound, as this makes it easier to adjust the first maximum transmittance difference and the second maximum transmittance difference to the above-mentioned ranges and preferred ranges. When only one kind of dichroic azo dye compound is used, it is also preferable to use the first dichroic azo dye compound. Furthermore, when the first dichroic azo dye compound, the second dichroic azo dye compound, and the third dichroic azo dye compound are used, the content of the first azo dye compound is preferably 40% by mass or more, and more preferably 45% by mass or more, of the total content of the first dichroic azo dye compound, the second dichroic azo dye compound, and the third dichroic azo dye compound.

[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] Furthermore, when the first optically absorptive anisotropic layer contains at least one dichroic substance, and when the first optically absorptive anisotropic layer contains only one dichroic substance or when the first optically absorptive anisotropic layer contains two or more dichroic substances, it is also preferable that the content of the dichroic substance with the largest content be 90% by mass or more relative to the total mass of the dichroic substances in the first optically absorptive anisotropic layer. Furthermore, when the second optically absorptive anisotropic layer contains at least one dichroic substance, and when the second optically absorptive anisotropic layer contains only one dichroic substance or when the second optically absorptive anisotropic layer contains two or more dichroic substances, it is also preferable that the content of the dichroic substance with the largest content be 90% by mass or more relative to the total mass of the dichroic substances in the second optically absorptive anisotropic layer.

[0045] (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.

[0046] 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.

[0047]

[0048] 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.

[0049] 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.

[0050]

[0051] 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 ４ each 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.

[0052] 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, R３ and R ４ each 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.

[0053] 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.

[0054] 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.

[0055] 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).

[0056] 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 higher. These terminal groups may be further substituted with these groups or with the polymerizable groups described in JP-A-2010-244038.

[0057] 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.

[0058] 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.

[0059] 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)

[0060] 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] ).

[0061] 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):

[0062]

[0063] 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)

[0064] 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.

[0065] 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.

[0066] 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.

[0067] Particularly preferred examples of the polymerizable group include those represented by any of the above formulae (P-1) to (P-20).

[0068] 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.

[0069] 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

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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).

[0077] 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.

[0078] (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.

[0079] 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.

[0080] Formula (A)

[0081] 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.

[0082] The onium salt is preferably a compound represented by formula (B).

[0083] Formula (B)

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] (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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] (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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] The thickness of the optically absorptive anisotropic layer is not particularly limited, but is preferably 0.5 to 7 μm, more preferably 1.0 to 3 μm.

[0105] [Optically Anisotropic Layer] The optical film of the present invention includes at least one optically anisotropic layer. In the optical film of the present invention, the number of optically anisotropic layers disposed between the first optically absorptive anisotropic layer and the second optically absorptive anisotropic layer may be two or more, or may be three or more. The number of the optically anisotropic layers is usually 10 or less, and often 5 or less.

[0106] Examples of the optically anisotropic layer include an A plate, a B plate, and a C plate.

[0107] There are two types of A plates: positive A plates (positive A plates, +A plates) and negative A plates (negative A plates, -A plates). When the refractive index in the in-plane slow axis direction of the film is nx, the refractive index in the in-plane direction perpendicular to the in-plane slow axis is ny, and the refractive index in the thickness direction is nz, the positive A plate satisfies the relationship of formula (A1), and the negative A plate satisfies the relationship of formula (A2). Note that the positive A plate exhibits a positive Rth value, while the negative A plate exhibits a negative Rth value. Note that the in-plane slow axis direction of the film is the direction in which the in-plane refractive index is maximum. Formula (A1) nx>ny≒nz Formula (A2) ny<nx≒nz Note that the above "≒" encompasses not only the case where both are completely identical, but also the case where both are substantially identical. The term "substantially the same" means that, for example, "ny ≒ nz" includes cases where (ny - nz) x d is -10 to 10 nm, preferably -5 to 5 nm, and "nx ≒ nz" also includes cases where (nx - nz) x d is -10 to 10 nm, preferably -5 to 5 nm. In (ny - nz) x d, d is the thickness of the film.

[0108] B plates have different values ​​for nx, ny, and nz, and there are two types: B plates with negative Rth that satisfy the relationship of formula (B1), and B plates with positive Rth that satisfy the relationship of formula (B2). Formula (B1) (nx+ny) / 2>nz Formula (B2) (nx+ny) / 2<nz The Nz coefficient of the B plate is preferably 1.5 or more, more preferably 2.0 to 10.0, and even more preferably 3.0 to 5.0. The Nz coefficient means a value expressed as Nz = (nx-nz) / (nx-ny).

[0109] There are two types of C plates: positive C plates (positive C plates, +C plates) and negative C plates (negative C plates, -C plates). Positive C plates satisfy the relationship of formula (C1), while negative C plates satisfy the relationship of formula (C2). Note that a positive C plate exhibits a negative Rth value, while a negative C plate exhibits a positive Rth value. Formula (C1) nz>nx≒ny Formula (C2) nz<nx≒ny Note that the above "≒" encompasses not only the case where both are completely identical, but also the case where both are substantially identical. "Substantially the same" means, for example, that "nx≒ny" also includes the case where (nx-ny)×d is 0 to 10 nm, preferably 0 to 5 nm. Note that in (ny-nz)×d, d is the film thickness.

[0110] The optically anisotropic layer is preferably an A plate or a B plate, more preferably an A plate, and even more preferably a negative A plate. The in-plane retardation of the optically anisotropic layer is preferably 100 to 300 nm, more preferably 150 to 280 nm, and even more preferably 170 to 220 nm, in that the change in color is smaller when viewed from an oblique direction while changing the azimuth angle. It is also preferable that the optical film of the present invention includes two optically anisotropic layers, and the in-plane retardation of the optically anisotropic layer is within the above-mentioned preferred range. When the optical film of the present invention includes two optically anisotropic layers, the angle between the in-plane slow axis directions of the two optically anisotropic layers is preferably 30 to 65°, more preferably 40 to 50°, and even more preferably 42 to 48°.

[0111] 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.

[0112] 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.

[0113] 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 with 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.

[0114] 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 cyclohexane derivatives 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.

[0115] Discotic liquid crystal molecules also include compounds exhibiting liquid crystallinity, which have a structure in which linear alkyl groups, alkoxy groups, or substituted benzoyloxy groups are radiatingly 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 certain 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.

[0116] In order to fix the discotic liquid crystal molecules by polymerization, it is preferable that a polymerizable group be bonded as a substituent to the discotic core of the discotic liquid crystal molecule. The discotic core and the polymerizable group are preferably bonded via a linking group, which allows the alignment state to be maintained even during the polymerization reaction. Examples of such compounds include those described in paragraphs

[0151] to

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

[0117] In the optical film 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.

[0118] In the optical film of the present invention, it is also preferred 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).

[0119] Furthermore, for the reason that the light blocking ability for obliquely incident light can be improved, it is also preferable that the optically anisotropic layer has two layers, and 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 preferable 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.It is also preferable that both of the two optically anisotropic layers are formed using compositions containing discotic liquid crystal compounds.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, polymerizable liquid crystal compounds with reverse wavelength dispersion and polymerizable liquid crystal compounds with forward wavelength dispersion).

[0120] In the optical film 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. Here, the polymerization conditions are not particularly limited, but ultraviolet light is preferably used in 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.

[0121] The optically anisotropic layer may also include a liquid crystal compound that is twisted and aligned with the thickness direction as the helical axis. The twisted alignment with the thickness direction as the helical axis described above is also called "twist alignment." A layer containing a twisted liquid crystal compound is also called a "twist layer." Here, an example of a method for forming an optically anisotropic layer containing a twisted liquid crystal compound is a method 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 light irradiation. The direction of the helix induction force is not particularly limited. The chiral agent may or may not exhibit liquid crystallinity.

[0122] 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.

[0123] The twist angle of the liquid crystal compound is, for example, 60 to 300°, preferably more than 85°, and more preferably 250° or more. The twist angle is preferably 280° or less, and more preferably 275° 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.

[0124] The twist direction of the liquid crystal compound may be either counterclockwise or clockwise.

[0125] Furthermore, when the optically anisotropic layer is a twist layer, the product Δnd of the refractive index anisotropy Δn and the thickness d is preferably 300 to 800 nm. Δnd of the optically anisotropic layer is more preferably 350 nm or more, and even more preferably 400 nm or more. Δnd is more preferably 750 nm or less, and even more preferably 700 nm or less. The value of Δnd can be adjusted by the type of liquid crystal compound used to form the optically anisotropic layer and the thickness of the optically anisotropic layer.

[0126] 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.

[0127] In the optical film of the present invention, when two optically anisotropic layers are included, 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, for the reason that the light-shielding property for obliquely incident light is improved. 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, the layers 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), the layers are laminated via only those two.

[0128] Although the above describes an embodiment in which the optically anisotropic layer contains a liquid crystal compound, the optically anisotropic layer may be in other embodiments, such as a polymer film. The polymer film is preferably a stretched polymer film (stretched film). Known materials for the stretched film can be used without limitation, including polyesters such as polyethylene terephthalate (PET), polycarbonates, acrylic resins, epoxy resins, polyurethanes, polyamides, polyolefins, cycloolefin resins, and cellulose derivatives. Among these, cycloolefin resins are preferred as materials for the stretched film from the viewpoint of front transmittance. That is, the polymer film is preferably a stretched cycloolefin film. When the optically anisotropic layer is a polymer film, the preferred range of in-plane retardation is as described above.

[0129] The optical film of the present invention may have another optically anisotropic layer, such as a positive C plate, between the first optically anisotropic layer and the second optically anisotropic layer.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] [Support] 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. The transparent support refers to a support having a visible light transmittance of 60% or more, preferably 80% or more, and more preferably 90% or more.

[0134] Examples of the support include glass substrates and polymer films.The materials of the polymer film include cellulose polymers, acrylic polymers having acrylic acid ester polymers such as polymethyl methacrylate and lactone ring-containing polymers, thermoplastic norbornene polymers, polycarbonate polymers, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, styrene polymers such as polystyrene and acrylonitrile-styrene copolymers, polyolefin polymers such as polyethylene, polypropylene and ethylene-propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamides, imide polymers, sulfone polymers, polyethersulfone polymers, polyetheretherketone polymers, polyphenylene sulfide polymers, vinylidene chloride polymers, vinyl alcohol polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers, epoxy polymers, and polymers made by mixing these polymers.

[0135] [Alignment Film] In 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.

[0136] [Adhesive Layer] 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.

[0137] 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.

[0138] The refractive index of the pressure-sensitive adhesive layer is preferably from 1.43 to 1.75, more preferably from 1.47 to 1.55.

[0139] [Adhesive Layer] The optical film 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.

[0140] 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.

[0141] [Other Layers] The film of the present invention may have layers other than those described above (other layers). Examples of other layers include an anti-reflection layer, a protective layer, an oxygen-blocking layer, an ultraviolet absorbing layer, and a blue light absorbing layer.

[0142] [Optical Film Characteristics] The optical film of the present invention preferably has a characteristic in which the transmittance is high in the direction of the transmittance central axis of the first optically absorptive anisotropic layer and the second optically absorptive anisotropic layer, and the transmittance of light from directions tilted from the transmittance central axis is low. The light transmittance of the optical film of the present invention in the transmittance central axis direction is preferably 70% or more, more preferably 79% or more, even more preferably 81% or more, and particularly preferably 85% or more. The upper limit of the transmittance is not particularly limited, but examples include 99% or less. The method for measuring the light transmittance in the transmittance central axis direction is described in the section on measuring the front transmittance in the Examples below. Specifically, the transmittance is the luminous efficiency transmittance in the transmittance central axis direction.

[0143] Furthermore, the optical film of the present invention preferably has a light transmittance in a direction tilted from the transmittance central axis of 50% or less, more preferably 40% or less, even more preferably 30% or less, and particularly preferably 20% or less. The lower limit of the transmittance is not particularly limited, but may be, for example, 1% or more. The light transmittance in a direction tilted from the transmittance central axis direction is described in the section on the measurement method for light-blocking properties in the Examples below. Specifically, the transmittance is the transmittance of light in a direction at a polar angle of 60° from the transmittance central axis direction, and is the transmittance value of the wavelength showing the lowest transmittance among wavelengths of 400 to 700 nm.

[0144] <Head-Mounted Display> The optical film of the present invention can be applied to, for example, various display devices. The optical film of the present invention may have the property of high transmittance in the direction of the transmittance central axis of the first optically absorptive anisotropic layer and the second optically absorptive anisotropic layer, and low transmittance for light from directions tilted from the transmittance central axis. Therefore, for example, it can be used for controlling the viewing angle of a display device. Furthermore, the optical film of the present invention has the property of causing little change in color when viewed from an oblique direction while changing the azimuth angle. Therefore, when applied to a display device, the same color can be easily viewed even when the azimuth angle is changed.

[0145] Among these, a head-mounted display is a preferred example of the display device. 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. Here, it can be said that in AR glasses, external light that causes the above-mentioned rainbow unevenness is often incident on the AR glasses from above the user at an oblique direction. When the optical film of the present invention is applied to AR glasses, external light incident on the diffractive element provided in the AR glasses from above the user (above the head) can be effectively blocked.

[0146] 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.

[0147] FIG. 3 is a cross-sectional schematic diagram showing a portion of AR glasses (head-mounted displays of the present invention). Specifically, the AR glasses 100 shown in FIG. 3 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 member 50 that includes a cover glass 52 and an optical film 10. In the optical member 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 3 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.

[0153] 3, 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 the AR glasses 100 of the embodiment shown in FIG. 3, 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.

[0154] 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 of the present invention (AR glasses 100) including the optical film of the present invention. In the optical device 60, the optical member 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 member 50 so as to overlap the above-mentioned area, it becomes difficult for external light 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.

[0155] 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.

[0156] Example 1 Preparation of Lightly Absorbing Anisotropic Film AX (Formation of Alignment Film 1) The surface of a 40 μm-thick cellulose acylate film (manufactured by Fujifilm Corporation, product name Fujitac TG60UL) was saponified with an alkaline solution, and the following composition for forming an alignment film 1 was applied thereon using a wire bar. The support on which the coating film was formed was dried with hot air at 60°C for 60 seconds and then with hot air at 100°C for 120 seconds to form alignment film 1, thereby obtaining a TAC film with an alignment film. The thickness of alignment film 1 was 1 μm.

[0157] ------------------------------------------------------------------ Composition 1 for forming alignment film -------------------------------------------------- 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 ------------------------------------------------------------------

[0158] Modified polyvinyl alcohol PVA-1

[0159] (Formation of Optically Absorbent Anisotropic Layer A) The following composition for forming the optically absorbent anisotropic layer A was continuously applied onto the obtained alignment film 1 using a wire bar, heated at 120°C for 60 seconds, and then cooled to room temperature (23°C). Next, it was heated at 75°C for 60 seconds and cooled again to room temperature. Thereafter, an LED lamp (center wavelength 365 nm) was used to illuminate the layer at an illuminance of 200 mW / cm. ２ The alignment film 1 was irradiated with ultraviolet light for 2 seconds under the irradiation conditions of 1.0 μm to form an optically absorbing anisotropic layer A on the alignment film 1, thereby obtaining an optically absorbing anisotropic film AX. The optically absorbing anisotropic layer A had a thickness of 1.8 μm.

[0160] -------------------------------- Composition of composition for forming optically absorptive anisotropic layer A-------------------------------- 0.60 parts by mass of dichroic material D-1 below 4.83 parts by mass of polymer liquid crystal compound P-1 below 2.57 parts by mass of liquid crystal compound L-1 below 0.13 parts by mass of IRGACUREOXE-02 (manufactured by BASF) 0.10 parts by mass of compound E-1 below 0.18 parts by mass of compound E-2 below 0.011 parts by mass of surfactant F-1 below 82.43 parts by mass of cyclopentanone 9.16 parts by mass of benzyl alcohol --------------------------------

[0161] Dichroic substance D-1

[0162] Polymer liquid crystal compound P-1

[0163] 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]

[0164] Compound E-1

[0165] Compound E-2

[0166] Surfactant F-1 (In the following formula, TMS represents a trimethylsilyl group.)

[0167] The direction of the central axis of transmittance was measured by measuring the transmittance of the prepared optically absorptive anisotropic layer A while changing the polar angle and azimuthal angle using an AxoScan OPMF-2 (manufactured by Axometrics). As a result, the angle between the central axis of transmittance of the first optically absorptive anisotropic layer and the normal direction to the surface of the first optically absorptive anisotropic layer was 0°.

[0168] The above-mentioned average transmittance T Ａ４５０ , average transmittance T Ａ５５０ and average transmittance T Ａ６５０ Specifically, an AxoScan OPMF-2 (manufactured by Axometrics) was used to determine the transmittance when P-polarized light having wavelengths of 450 nm, 550 nm, and 650 nm was incident from four directions of azimuth angles of 0°, 90°, 180°, and 270°, where the polar angle was set to 60° and one in-plane direction of the optically absorptive anisotropic layer A was set to an azimuth angle of 0°. The average value at a wavelength of 450 nm (average transmittance T Ａ４５０ ) is 20%, and the average value at a wavelength of 550 nm (average transmittance T Ａ５５０ ) is 65%, and the average value at a wavelength of 650 nm (average transmittance T Ａ６５０ When determining the transmittance of the optically absorptive anisotropic layer A, the transmittances of the support and the alignment film were measured in advance, and the influence of these transmittances was eliminated before determining the transmittance of the optically anisotropic layer A.

[0169] [Preparation of Optically Anisotropic Film PX] (Formation of Alignment Film 2) The following composition for alignment film 2 was continuously coated on one side of a 40 μm thick cellulose acylate film (TAC substrate; manufactured by Fujifilm Corporation, TG40) using a #14 wire bar. After coating, the coating was dried with hot air at 60° C. for 60 seconds and then with hot air at 100° C. for 120 seconds to form a coating film.

[0170] ------------------------------------------------------------------ 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

[0171] The coating film was subjected to a continuous rubbing treatment. At this time, the longitudinal direction of the long film was parallel to the conveying direction, and the angle between the longitudinal direction of the film and the rotation axis of the rubbing roller was 90°. That is, the film width direction was set to 0°, the film longitudinal direction was set to 90°, and when observed from the alignment film side, the clockwise direction with the film width direction as the reference was expressed as a positive value, and the rotation axis of the rubbing roller was 0°. By the above procedure, alignment film 2 was formed.

[0172] (Formation of Optically Anisotropic Layer P) An optically anisotropic layer coating solution 1 containing a discotic liquid crystal compound of the following composition was continuously applied to the alignment film 2 prepared above using a #5.0 wire bar to prepare an optically anisotropic layer P. 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 hot air at 130°C for 90 seconds, followed by hot air at 100°C for 60 seconds, and then irradiated with UV at 80°C to fix the alignment of the liquid crystal compound. Using the above procedure, an optically anisotropic layer P was formed on the alignment film 2, yielding an optically anisotropic film PX. The Re at 550 nm of the optically anisotropic layer P 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. The optically anisotropic layer P corresponds to a negative A plate.

[0173] -------------------------------- Composition of coating solution 1 for optically anisotropic layer ---------------------------------- 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-2 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 ----------------------------------

[0174] Discotic Liquid Crystal-1

[0175] Discotic Liquid Crystal-2

[0176] Alignment film interface alignment agent-1

[0177] Alignment film interface alignment agent-2

[0178] Surfactant F-2

[0179] [Preparation of Optical Film A1] The surface of the optically absorptive anisotropic film AX on the optically absorptive anisotropic layer A side and the surface of the optically anisotropic film PX on the support side were bonded together using an adhesive (Opteria (registered trademark) NCF-D692 (film thickness: 15 μm, manufactured by Lintec Corporation)). Next, an optically anisotropic film PX other than the bonded optically anisotropic film PX was prepared, and the surface of the other optically anisotropic film PX on the optically anisotropic layer P side was bonded together using an adhesive (NCF-D692). In this case, the direction of bonding was adjusted so that the angle between the in-plane slow axis directions of the two bonded optically anisotropic layers P was 45°. Next, the support-side surface of the laminated optically anisotropic film PX was laminated to the support-side surface of another optically absorbing anisotropic film AX prepared separately from the laminated optically absorbing anisotropic film AX, and the support-side surface of the other optically absorbing anisotropic film AX was laminated to the support-side surface of the optically absorbing anisotropic layer A using a pressure-sensitive adhesive (NCF-D692), thereby producing optical film A1. The layer structure of optical film A1 was "support / alignment film 1 / optically absorbing anisotropic layer A / pressure-sensitive adhesive / support / alignment film 2 / optically anisotropic layer P / pressure-sensitive adhesive / optically anisotropic layer P / alignment film 2 / support / pressure-sensitive adhesive / optically absorbing anisotropic layer A / alignment film 1 / support."

[0180] <Example 2> [Preparation of optically anisotropic film QX] In forming the optically anisotropic layer P of the optically anisotropic film PX of Example 1, the optically anisotropic layer Q was formed in the same manner as in Example 1, except that the film thickness of the coating layer was adjusted so that the Re at 550 nm was 210 nm, and the optically anisotropic film QX was obtained.

[0181] [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, the optically anisotropic film PX was changed to the optically anisotropic film QX.

[0182] Example 3 [Preparation of optically absorptive anisotropic film BX] In the formation of optically absorptive anisotropic layer A of the optically absorptive anisotropic film AX of Example 1, an optically absorptive anisotropic layer B was formed in the same manner as in Example 1, except that the composition for forming optically absorptive anisotropic layer A was changed to the composition for forming optically absorptive anisotropic layer B described below, thereby obtaining an optically absorptive anisotropic film BX.

[0183] 0.16 parts by mass of the dichroic substance D-2 below; 0.48 parts by mass of the dichroic substance D-3 below; 4.16 parts by mass of the polymer liquid crystal compound P-1 above; 2.57 parts by mass of the liquid crystal compound L-1 above; 0.13 parts by mass of IRGACUREOXE-02 (manufactured by BASF); 0.10 parts by mass of the compound E-1 above; 0.18 parts by mass of the compound E-2 above; 0.011 parts by mass of the surfactant F-1 above; 82.43 parts by mass of cyclopentanone; 9.16 parts by mass of benzyl alcohol ----------------------------------------------------------------------------------

[0184] Dichroic substance D-2

[0185] Dichroic substance D-3

[0186] Dichroic substance D-4

[0187] [Preparation of Optical Film A3] Optical film A3 was prepared in the same manner as in Example 2, except that in the preparation of optical film A2 in Example 2, optically absorptive anisotropic film AX was changed to optically absorptive anisotropic film BX.

[0188] Example 4 [Preparation of optically absorptive anisotropic film CX] In the preparation of optically absorptive anisotropic film AX in Example 1, the composition for forming optically absorptive anisotropic layer A was changed to the composition for forming optically absorptive anisotropic layer C described below, and the film thickness of the optically absorptive anisotropic layer was adjusted to 1.1 μm. In the same manner as in Example 1, optically absorptive anisotropic layer C was formed, and optically absorptive anisotropic film CX was obtained.

[0189] 0.16 parts by mass of the compound E-1; 0.016 parts by mass of the compound E-2; 0.16 parts by mass of the compound E-3; 0.45 parts by mass of the dichroic material D-4; 0.59 parts by mass of the dichroic material D-2; 0.15 parts by mass of the dichroic material D-3; 3.87 parts by mass of the polymer liquid crystal compound P-1; 2.40 parts by mass of the liquid crystal compound L-1; 0.12 parts by mass of IRGACUREOXE-02 (manufactured by BASF); 0.09 parts by mass of the compound E-1; 0.16 parts by mass of the compound E-2; 0.016 parts by mass of the surfactant F-1; 82.93 parts by mass of cyclopentanone; 9.21 parts by mass of benzyl alcohol ----------------------------------------------------------------------------------

[0190] [Preparation of Optical Film A4] Optical film A4 was prepared in the same manner as in Example 2, except that in the preparation of optical film A2 in Example 2, optically absorptive anisotropic film AX was changed to optically absorptive anisotropic film CX.

[0191] Example 5 [Preparation of optically absorptive anisotropic film DX] In the preparation of optically absorptive anisotropic film AX in Example 1, the composition for forming optically absorptive anisotropic layer A was changed to the composition for forming optically absorptive anisotropic layer D described below, the heating step at 75°C for 60 seconds was changed to heating at 80°C for 60 seconds, and the film thickness of the optically absorptive anisotropic layer was adjusted to 3.6 µm. Except for this, optically absorptive anisotropic layer D was formed in the same manner as in Example 1, and optically absorptive anisotropic film DX was obtained.

[0192] -------------------------------- Composition of composition for forming light absorption anisotropic layer D------------------------------------------------ Dichroic material D-1: 0.55 parts by mass Polymer liquid crystal compound P-1: 4.88 parts by mass Liquid crystal compound L-1: 2.57 parts by mass IRGACUREOXE-02 (manufactured by BASF) 0.13 parts by mass Compound E-1: 0.10 parts by mass Compound E-2: 0.18 parts by mass Surfactant F-1: 0.011 parts by mass Cyclopentanone: 82.43 parts by mass Benzyl alcohol: 9.16 parts by mass

[0193] [Preparation of Optical Film A5] Optical film A5 was prepared in the same manner as in Example 2, except that in the preparation of optical film A2 in Example 2, the optically absorptive anisotropic film AX was changed to the optically absorptive anisotropic film DX.

[0194] Example 6 [Preparation of Optically Absorbent Anisotropic Film EX] In the preparation of optically absorptive anisotropic film AX of Example 1, optically absorptive anisotropic layer E was formed and optically absorptive anisotropic film EX was obtained in the same manner as in Example 1, except that in the preparation of optically absorptive anisotropic film AX of Example 1, the composition for forming optically absorptive anisotropic layer A was changed to the composition for forming optically absorptive anisotropic layer E described below, the heating step at 75°C for 60 seconds was changed to heating at 70°C for 60 seconds, and the film thickness of the optically absorptive anisotropic layer was adjusted to 3.2 µm.

[0195] -------------------------------- Composition of composition for forming light absorption anisotropic layer E-------------------------------- Dichroic material D-4 1.00 parts by mass Polymer liquid crystal compound P-1 6.61 parts by mass Liquid crystal compound L-1 2.44 parts by mass IRGACUREOXE-02 (manufactured by BASF) 0.18 parts by mass Compound E-1 0.14 parts by mass Compound E-2 0.14 parts by mass Surfactant F-1 0.007 parts by mass Cyclopentanone 80.53 parts by mass Benzyl alcohol 8.95 parts by mass

[0196] [Preparation of Optical Film A6] Optical film A6 was prepared in the same manner as in Example 2, except that the optically absorptive anisotropic layer A in the preparation of optical film A2 in Example 2 was changed to optically absorptive anisotropic layer E.

[0197] Example 7 (Formation of optically absorbing anisotropic film FX) In the preparation of the optically absorbing anisotropic film AX of Example 1, the composition for forming the optically absorbing anisotropic layer A was changed to the composition for forming the optically absorbing anisotropic layer F described below, and the film thickness of the optically absorbing anisotropic layer was adjusted to 0.7 μm. An optically absorbing anisotropic layer F was formed in the same manner as in Example 1, to obtain an optically absorbing anisotropic film FX.

[0198] -------------------------------- Composition of composition for forming light absorption anisotropic layer F------------------------------------------------ Dichroic material D-1: 0.68 parts by mass Polymer liquid crystal compound P-1: 3.18 parts by mass Liquid crystal compound L-1: 1.83 parts by mass IRGACUREOXE-02 (manufactured by BASF) 0.09 parts by mass Compound E-1: 0.07 parts by mass Compound E-2: 0.13 parts by mass Surfactant F-1: 0.020 parts by mass Cyclopentanone: 84.60 parts by mass Benzyl alcohol: 9.40 parts by mass

[0199] [Preparation of Optical Film A7] Optical film A7 was prepared in the same manner as in Example 2, except that in the preparation of optical film A2 in Example 2, the optically absorptive anisotropic film AX was changed to the optically absorptive anisotropic film FX.

[0200] Example 8 Preparation of Optically Anisotropic Film R Optically anisotropic film R was prepared according to the following procedure.

[0201] (Extrusion molding) Cycloolefin resin ARTON G7810 (manufactured by JSR Corporation) was dried at 100°C for 2 hours or more and melt-extruded at 280°C using a twin-screw kneading extruder. At this time, a screen filter, a gear pump, and a leaf disc filter were arranged in this order between the extruder and the die, and these were connected by melt piping. In addition, the above melt extrusion was performed from a T-die with a width of 1000 mm and a lip gap of 1 mm, and cast onto a triple cast roll set at 180°C, 175°C, and 170°C to obtain an unstretched film.

[0202] (Stretching and Heat Fixation) The unstretched film being transported was subjected to a stretching step by the following method.

[0203] (Longitudinal Stretching) The unstretched film was longitudinally stretched using a roll-to-roll longitudinal stretching machine having an aspect ratio (L / W) of 0.2 while being conveyed under the following conditions: -Conditions- Preheating temperature: 175°C Stretching temperature: 175°C Stretching ratio: 90%

[0204] The stretched film obtained had an Re of 210 nm at 550 nm, an Rth of 110 nm, and a thickness of 25 μm. The stretched film obtained by the above procedure was designated as optically anisotropic film R.

[0205] [Preparation of Pressure-Sensitive Adhesive Layer Y] An acrylate-based polymer was prepared according to the following procedure to prepare Pressure-Sensitive Adhesive Layer Y. 43 parts by mass of butyl acrylate, 55 parts by mass of benzyl acrylate, 3 parts by mass of acrylic acid, and 0.3 parts by mass of 2,2'-azobisisobutyronitrile were added together with ethyl acetate to a reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer, and a stirrer to obtain a mixed solution with a solids concentration of 30% by mass. The mixed solution was reacted at 60°C for 4 hours under a nitrogen gas stream to obtain an acrylate-based polymer solution. The average refractive index of the obtained acrylate-based polymer was measured using an Abbe refractometer (manufactured by Atago Co., Ltd.) in an environment of 23.5 to 26.5°C, and was found to be 1.52.

[0206] Next, a pressure-sensitive adhesive layer Y was produced using the obtained acrylate polymer solution according to the following procedure. 2 parts by mass of trimethylolpropane tolylene diisocyanate (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) and 0.1 parts by mass of 3-glycidoxypropyltrimethoxysilane were added to 100 parts by mass of the acrylate polymer solid content of the acrylate polymer solution to obtain a coating solution. The coating solution was applied using a die coater to a separate film that had been surface-treated with a silicone-based release agent, and dried at 150°C for 3 hours to obtain a pressure-sensitive adhesive layer Y. The thickness of the pressure-sensitive adhesive layer Y was 15 μm.

[0207] [Preparation of Optical Film A8] Optical film A8 was prepared in the same manner as in Example 7, except that the adhesive (Opteria (registered trademark) NCF-D692 (film thickness: 15 μm, manufactured by Lintec Corporation)) used in the preparation of optical film A7 in Example 7 was changed to adhesive layer Y, and the optically anisotropic film QX was changed to optically anisotropic film R.

[0208] Comparative Example 1 [Preparation of Optically Absorbent Anisotropic Film GX] In the preparation of optically absorptive anisotropic film AX in Example 1, optically absorptive anisotropic layer G was formed and optically absorptive anisotropic film GX was obtained in the same manner as in Example 1, except that the composition for forming optically absorptive anisotropic layer A was changed to the composition for forming optically absorptive anisotropic layer G described below, and the heating step at 75°C for 60 seconds was changed to heating at 85°C for 60 seconds.

[0209] 0.18 parts by mass of the compound E-2; 0.011 parts by mass of the compound F-3; 0.44 parts by mass of the dichroic material D-4; 0.11 parts by mass of the dichroic material D-2; 0.72 parts by mass of the dichroic material D-3; 4.15 parts by mass of the polymer liquid crystal compound P-1; 2.57 parts by mass of the liquid crystal compound L-1; 0.13 parts by mass of IRGACUREOXE-02 (manufactured by BASF); 0.10 parts by mass of the compound E-1; 0.18 parts by mass of the compound E-2; 0.011 parts by mass of the surfactant F-1; 82.43 parts by mass of cyclopentanone; 9.16 parts by mass of benzyl alcohol ----------------------------------------------------------------------------------

[0210] [Preparation of Optical Film B1] Optical film B1 was prepared in the same manner as in Example 1, except that the optically absorptive anisotropic film AX in the preparation of optical film A1 in Example 1 was changed to optically absorptive anisotropic film GX.

[0211] The average transmittance T Ａ４５０ , average transmittance T Ａ５５０ and average transmittance T Ａ６５０ was measured in the same manner as for the optically absorptive anisotropic layer A. The results are shown in the table below.

[0212] <Evaluation> The prepared optical films A1 to A8 and B1 were measured using a goniospectrophotometric colorimeter (GSP-2B, manufactured by Murakami Color Research Laboratory Co., Ltd.) More specifically, the following color change, front transmittance, and light-blocking property were evaluated by the following procedures.

[0213] [Color Change] Using the goniospectrophotometric colorimetry system described above, chromaticity in the XYZ color system under illuminant D65 was measured while fixing the polar angle at 60° and varying the orientation from 0° to 330° in 30° increments. Here, chromaticity is a value on the xy chromaticity diagram of the CIE 1931 color space. The amount of color change between each measured chromaticity was calculated to obtain the maximum amount of color change. The amount of chromaticity change ΔC12 between chromaticity C1 (x1, y1) and chromaticity C2 (x2, y2) was calculated using the following formula: ΔC12 = {(x2 - x1) ２ +(y2-y1) ２} ０．５ The color change was evaluated based on the maximum color change amount according to the following criteria. In practical terms, an A rating or a B rating is preferable, with an A rating being more preferable. A: The maximum color change amount is less than 0.015. B: The maximum color change amount is 0.015 or more but less than 0.070. C: The maximum color change amount is 0.70 or more.

[0214] [Front Transmittance] The luminous transmittance (Y value) was measured at a polar angle of 0° using the above-described goniospectrophotometric colorimetry system, and this transmittance was taken as the front transmittance (unit: %).

[0215] [Light-blocking properties] The polar angle was fixed at 60°, and the orientation was changed from 0° to 330° in 30° increments. The transmittance was measured at wavelengths of 400 to 700 nm in 10 nm increments using the goniospectrophotometric colorimetry system described above. The transmittance spectrum for wavelengths of 400 to 700 nm was calculated by averaging the measured values ​​in all orientations. The lowest transmittance value (unit: %) in the transmittance spectrum was determined.

[0216] <Results> The configuration of the optical film of each Example and Comparative Example and the above evaluation results are shown in Table 1. In Table 1, the configuration of the optical film of each Example and Comparative Example is, from top to bottom, the first optically absorptive anisotropic layer, the first optically anisotropic layer, the second optically anisotropic layer, and the second optically absorptive anisotropic layer contained in the optical film. In Table 1, the average transmittance T Ｂ４５０ , average transmittance T Ｂ５５０ and average transmittance T Ｂ６５０ The value of is the average transmittance T Ａ４５０ , average transmittance T Ａ５５０ and average transmittance T Ａ６５０ Since the values ​​are the same as those in Table 1, the description is omitted. In Table 1, the column "Ratio of dichroic substances contained" indicates the ratio of the dichroic substances contained in each of the first optically absorptive anisotropic layer and the second optically absorptive anisotropic layer. For example, the notation "D-4 (50%) / D-2 (12%) / D-3 (38%)" indicates that the content of the dichroic substance D-4 contained in the optically absorptive anisotropic layer is 50% by mass, the content of the dichroic substance D-4 is 12% by mass, and the content of the dichroic substance D-3 is 38% by mass, relative to the total mass of the dichroic substances contained in the optically absorptive anisotropic layer. In Table 1, the value in parentheses in the lower row of the "Color Change" column is the value of the maximum color change amount.

[0217]

[0218] From the results shown in Table 1, it was confirmed that, compared to Comparative Example 1 in which the maximum transmittance difference was less than 10%, the optical films of each Example in which the maximum transmittance difference was 10% or more showed less change in color when viewed from an oblique direction while changing the azimuth angle. Comparison of Examples 3 and 4 with Examples 2 and 5 to 8 confirmed that the above-mentioned color change was smaller when the first optically absorptive anisotropic layer contained at least one dichroic substance, and when the first optically absorptive anisotropic layer contained only one dichroic substance or when the first optically absorptive anisotropic layer contained two or more dichroic substances, the content of the dichroic substance with the largest content was 90 mass% or more relative to the total mass of the dichroic substances in the first optically absorptive anisotropic layer; and when the second optically absorptive anisotropic layer contained at least one dichroic substance, and when the second optically absorptive anisotropic layer contained only one dichroic substance or when the second optically absorptive anisotropic layer contained two or more dichroic substances, the content of the dichroic substance with the largest content was 90 mass% or more relative to the total mass of the dichroic substances in the second optically absorptive anisotropic layer. From a comparison between Example 1 and Example 2, it was confirmed that when two optically anisotropic layers are included and the in-plane retardation of the optically anisotropic layer at a wavelength of 550 nm is 170 to 220 nm, the above-mentioned color change becomes smaller.

[0219] 10 Optical film 22 First optically absorptive anisotropic layer 24 Second optically absorptive anisotropic layer 32 First optically anisotropic layer 34 Second 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, in this order, a first optically absorptive anisotropic layer, at least one optically anisotropic layer, and a second optically absorptive anisotropic layer, 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°, and 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°, and the transmittance is measured by incident P-polarized light of wavelengths of 450 nm, 550 nm, and 650 nm from a direction tilted by 60° with respect to the normal direction to the surface of the first optically absorptive anisotropic layer, and this operation is repeated four times while changing the azimuth angle by 90°, to measure the average transmittance T at a wavelength of 450 nm. Ａ４５０ , average transmittance T at a wavelength of 550 nm Ａ５５０ , average transmittance T at a wavelength of 650 nm Ａ６５０ When the average transmittance T Ａ４５０ , the average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ The largest value among these and the average transmittance T Ａ４５０ , the average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ and the difference between the average transmittance T at a wavelength of 450 nm and the smallest value among the above is 10% or more, and an operation of measuring the transmittance by incident P-polarized light of wavelengths of 450 nm, 550 nm, and 650 nm from a direction tilted by 60° with respect to the normal direction of the surface of the second optically absorptive anisotropic layer is repeated four times while changing the azimuth angle by 90°. Ｂ４５０ , average transmittance T at a wavelength of 550 nm Ｂ５５０ , average transmittance T at a wavelength of 650 nm Ｂ６５０ When the average transmittance T Ｂ４５０ , the average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ The largest value among these and the average transmittance T Ｂ４５０ , the average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ The difference between the smallest value of the above is 10% or more.

2. The average transmittance T Ａ４５０ , the average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ and the wavelength at which the average transmittance T Ｂ４５０ , the average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ The wavelength showing the largest value among the average transmittance T Ａ４５０ , the average transmittance T Ａ５５０ and the average transmittance T Ａ６５０ and the wavelength at which the average transmittance T Ｂ４５０ , the average transmittance T Ｂ５５０ and the average transmittance T Ｂ６５０ The optical film according to claim 1 , wherein the wavelengths exhibiting the smallest values ​​of 3. An optical film according to claim 1 or 2, wherein the first optically absorptive anisotropic layer contains at least one dichroic substance, and when the first optically absorptive anisotropic layer contains only one dichroic substance or when the first optically absorptive anisotropic layer contains two or more dichroic substances, the content of the dichroic substance with the largest content is 90 mass% or more of the total mass of the dichroic substances in the first optically absorptive anisotropic layer; and the second optically absorptive anisotropic layer contains at least one dichroic substance, and when the second optically absorptive anisotropic layer contains only one dichroic substance or when the second optically absorptive anisotropic layer contains two or more dichroic substances, the content of the dichroic substance with the largest content is 90 mass% or more of the total mass of the dichroic substances in the second optically absorptive anisotropic layer.

4. The optical film according to claim 1 or 2, comprising two optically anisotropic layers, each of which has an in-plane retardation of 170 to 220 nm at a wavelength of 550 nm.

5. A head-mounted display comprising the optical film according to claim 1 or 2.

Images