Film, optical member, optical device, and head-mounted display

Abstract

The present invention addresses the problem of providing a film in which occurrence of ghosting is suppressed when the film is applied to AR glasses. This film includes at least one light-absorbing anisotropic layer, wherein the angle formed by the transmittance center axis of the light-absorbing anisotropic layer and the normal direction of the light-absorbing anisotropic layer is 0-45°, and the maximum height difference of waviness in a 10 mm x 10 mm region of the surface of the film is 1.2 μm or less.

Description

Films, optical components, optical devices, head-mounted displays

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

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

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

[0004] One method for suppressing rainbow unevenness is to arrange a film that suppresses external light from being incident at the above-mentioned angle with respect to the normal to the diffraction element. An example of a film having such a function is a film in which the absorption axis of the polarizer is perpendicular to the film surface of the polarizer, as described in Patent Document 1. Such a film makes it difficult for light in a direction tilted from the perpendicular to the film surface of the polarizer to pass through.

[0005] Japanese Patent Application Laid-Open No. 2008-165201

[0006] The present inventors have discovered that when they attempted to use a film produced with reference to the film described in Patent Document 1 to suppress rainbow unevenness in AR glass, the images sometimes appeared multiplexed (overlapping images occurred.) In particular, when the light guide plate of the AR glass and the cover member of the AR glass were arranged at a distance from each other and the film was placed on the light guide plate side of the cover member, the occurrence of overlapping images was more pronounced.

[0007] Therefore, an object of the present invention is to provide a film that suppresses the occurrence of overlapping images when applied to AR glasses, and also to provide an optical element, an optical device, and a head-mounted display that include the film.

[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] A film comprising at least one optically absorptive anisotropic layer, wherein the angle between the central axis of transmittance of the optically absorptive anisotropic layer and the normal direction to the optically absorptive anisotropic layer is 0 to 45°, and the maximum height difference of waviness in a 10 mm x 10 mm area on the film surface is 1.2 μm or less. [2] The film according to [1], which comprises two optically absorptive anisotropic layers and at least one retardation layer between the two optically absorptive anisotropic layers. [3] The film according to [2], which comprises two retardation layers, each of which is a λ / 2 plate. [4] The film according to any one of [1] to [3], further comprising a polarizer. [5] The film according to any one of [1] to [4], further comprising an antireflection layer disposed on the outermost side of the film. [6] The film according to any one of [1] to [5], which has a surface reflectance of 1% or less. [7] The film according to any one of [1] to [6], further comprising one or more layers selected from the group consisting of a pressure-sensitive adhesive layer having a thickness of 10 μm or less and an adhesive layer having a thickness of 10 μm or less. [8] An optical member comprising the film according to any one of [1] to [7] and a transparent support. [9] The optical member according to [8], wherein the transparent support is glass.

[10] An optical device comprising the optical member according to [8] and a light guide plate having a diffraction element disposed on its surface, wherein the optical member and the light guide plate are disposed at a distance from each other.

[11] The optical device according to

[10] , wherein the transparent support in the optical member is disposed closer to the light guide plate than the film.

[12] A head-mounted display comprising the optical device according to

[10] and an image display element.

[13] A head-mounted display comprising the optical device according to

[11] and an image display element.

[0010] According to the present invention, a film that suppresses the occurrence of overlapping images when applied to AR glasses can be provided. Furthermore, according to the present invention, an optical member, an optical device, and a head-mounted display that include the film can also be provided.

[0011] Fig. 1 is a schematic diagram showing an example of a first embodiment of the film of the present invention. Fig. 2 is a schematic diagram showing an example of a second embodiment of the film of the present invention. Fig. 3 is a schematic cross-sectional view showing a part of the AR glass of the present invention. Fig. 4 is a schematic cross-sectional view showing a part of the AR glass in the case where a conventional film for preventing rainbow unevenness is applied to the AR glass.

[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 OptoScience). By inputting the average refractive index ((nx + ny + nz) / 3) and film thickness (d (μm)) into 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 varying 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 OptoScience) 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 determined. Next, 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°, and the Mueller matrix at a wavelength of 550 nm is measured, thereby deriving the transmittance of the optically absorptive anisotropic layer. The resulting direction with the highest transmittance is designated the transmittance central axis. The transmittance central axis means the direction of the absorption axis (the direction of the long axis of the molecule) of the dichroic material contained in the light absorption anisotropic layer.

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

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

[0021] <Film> The film of the present invention is a film comprising at least one optically absorptive anisotropic layer of the present invention, wherein the angle between the central axis of transmittance of the optically absorptive anisotropic layer and the normal direction to the optically absorptive anisotropic layer is 0 to 45°, and the maximum height difference of waviness in a 10 mm × 10 mm region on the film surface is 1.2 μm or less. The method for measuring the maximum height difference of waviness will be described in detail later.

[0022] Although the mechanism by which the occurrence of overlapping images is suppressed when the film of the present invention is applied to AR glasses is not entirely clear, the inventors speculate as follows: First, the principle by which overlapping images are thought to occur when a film for preventing rainbow unevenness is applied to conventional AR glasses will be explained using drawings.

[0023] FIG. 4 is a schematic cross-sectional view showing a portion of AR glasses (head-mounted display) to which a conventional rainbow unevenness prevention film is applied. Specifically, the AR glasses 40C shown in FIG. 4 include an optical device 30C and an image display element 42 to which image light L1 is incident. The optical device 30C includes a light guide plate 32 and an incident diffraction element 34 and an exit diffraction element 36 disposed on the side of the light guide plate 32 opposite the image display element 42 side. The optical device 30C also includes an optical element 20C composed of a cover glass 22 and a film 10C (a conventional rainbow unevenness prevention film). In the optical element 20C, the film 10C is disposed on the light guide plate 32 side. Note that the film 10C is disposed at a distance from the incident diffraction element 34 and the exit diffraction element 36. The position of the incident diffraction element 34 corresponds to the position of incidence of the image light L1 from the image display element 42. The position of the output diffraction element 36 corresponds to the output position of the image light L1 from the light guide plate 32, i.e., the position where the user observes the image light L1. The input diffraction element 34 diffracts the image light L1 that enters the light guide plate 32 from the image display element 42, into the light guide plate 32. The diffracted image light L1 travels in the in-plane direction of the light guide plate 32 while being totally reflected within the light guide plate 32. The output diffraction element 36 diffracts the light that propagates through the light guide plate 32 toward the user.

[0024] The inventors' investigations revealed that in the output diffraction element 36 of such AR glasses 40C, a portion of the image light L1 is emitted toward the side opposite the user (the optical element 20C side), generating stray light Ls. The stray light Ls travels toward the optical element 20C and is partially reflected by the surface of the film 10C. The surface of the film 10C is often undulated, causing the stray light Ls to be reflected in a direction not parallel to the image light L1 and observed by the user. When the stray light Ls is reflected in a direction different from the image light L1, the image generated by the stray light Ls is observed at a different position from the image generated by the image light L1, which is thought to result in overlapping images.

[0025] On the other hand, since the maximum height difference of the waviness in a 10 mm x 10 mm area of ​​the film surface of the present invention is 1.2 μm or less, even if stray light Ls occurs, it is likely to be reflected in the same direction as the image light L1, and as a result, it is thought that the occurrence of overlapping images is suppressed (see Figure 3 described later). Below, a first embodiment and a second embodiment will be described in detail as representative embodiments of the film of the present invention. It should be noted that the film of the present invention is not limited to the following embodiments, and the components can be changed as appropriate.

[0026] [First embodiment] A first embodiment of the film of the present invention comprises two optically absorptive anisotropic layers and at least one retardation layer between the two optically absorptive anisotropic layers. The angle between the transmittance central axis of the two optically absorptive anisotropic layers and the normal direction of the optically absorptive anisotropic layers is 0 to 45°. The maximum height difference of the waviness in a 10 mm x 10 mm area on the film surface is 1.2 μm or less.

[0027] Fig. 1 is a schematic diagram showing an example of a first embodiment of the film of the present invention. The film 10A shown in Fig. 1 has, in this order, a first optically absorptive anisotropic layer 12a, a first retardation layer 14a, a second retardation layer 14b, and a second optically absorptive anisotropic layer 12b. The first optically absorptive anisotropic layer 12a and the second optically absorptive anisotropic layer 12b shown in Fig. 1 each have an angle of 0° between the transmittance central axis and the normal direction of the optically absorptive anisotropic layer (the first optically absorptive anisotropic layer 12a and the second optically absorptive anisotropic layer 12b) (corresponding to the black double-headed arrows in the first optically absorptive anisotropic layer 12a and the second optically absorptive anisotropic layer 12b in Fig. 1). In the embodiment shown in FIG. 1, the first retardation layer 14a and the second retardation layer 14b are λ / 2 plates, and the in-plane slow axis directions of the two are arranged so that the angle between them is 45° when observed from the normal direction (corresponding to the hollow double arrows in the first retardation layer 14a and the second retardation layer 14b in FIG. 1).

[0028] In the film of the first embodiment having the configuration shown in Figure 1, light incident in the direction of the central transmittance axis of the first optically absorptive anisotropic layer 12a and the second optically absorptive anisotropic layer 12b (the direction indicated by the solid arrow in Figure 1) is transmitted without undergoing polarization conversion. On the other hand, for light incident in a direction tilted from the central transmittance axis (the direction indicated by the hollow arrow in Figure 1), the component vibrating in the in-plane direction of the plane containing that direction and the central transmittance axis (hereinafter referred to as "P-polarized light") is partially absorbed by the first optically absorptive anisotropic layer 12a, while the component vibrating in the direction perpendicular to the P-polarized light (hereinafter referred to as "S-polarized light") is transmitted without being absorbed by the first optically absorptive anisotropic layer 12a. As a result, when light incident in a direction tilted from the central transmittance axis passes through the first optically absorptive anisotropic layer 12a, it becomes light with a large S-polarized component. In Fig. 1, the in-plane slow axis direction of the first retardation layer 14a is parallel to the plane including the direction tilted from the transmittance central axis and the transmittance central axis. In the embodiment shown in Fig. 1, the S-polarized component of light transmitted through the first optically absorptive anisotropic layer 12a undergoes almost no polarization conversion in the first retardation layer 14a, but undergoes polarization conversion in the second retardation layer 14b, where the vibration direction is rotated by approximately 90° to become a P-polarized component. Once converted into a P-polarized component, it is absorbed by the second optically absorptive anisotropic layer 12b. It can be said that the above-described light absorption is similar regardless of the azimuth angle of incidence, as long as it is in a direction tilted from the transmittance central axis. For example, in the case of light incident from a direction rotated 45° from the azimuth angle of the above-mentioned outline arrow and tilted from the transmittance central axis, the transmitted S-polarized component undergoes polarization conversion in the first retardation layer 14a and becomes a P-polarized component, while the second retardation layer 14b undergoes almost no polarization conversion, and the P-polarized component is absorbed by the second optically absorptive anisotropic layer 12b. As described above, in the embodiment shown in FIG. 1, light incident from any azimuth angle tilted from the transmittance central axis is absorbed by the first optically absorptive anisotropic layer 12a or the second optically absorptive anisotropic layer 12b. On the other hand, light incident from the transmittance central axis direction is transmitted without being absorbed. Therefore, when applied to AR glasses, the embodiment shown in FIG. 1 functions as a filter that has high transmittance for light incident from the transmittance central axis direction (e.g., the viewing direction) and low transmittance for light incident from an oblique direction.Such a filter can prevent external light from entering the diffraction element provided in the AR glass from an oblique direction, and therefore can suppress rainbow unevenness when applied to the AR glass.

[0029] Although the above description has been given of an embodiment in which two retardation layers are disposed between two optically absorbing anisotropic layers, the retardation layer disposed between the optically absorbing anisotropic layers may be a single layer. Even if there is only one retardation layer disposed between the optically absorbing anisotropic layers, it functions as a filter that absorbs light incident from an oblique direction and has a low transmittance for light incident from an oblique direction, based on the above-described principle. Hereinafter, a first embodiment of the film of the present invention will be described in detail.

[0030] (Maximum Height Difference of Waviness) As described above, in the first embodiment of the film of the present invention, the maximum height difference of waviness in a 10 mm x 10 mm area is 1.2 μm or less. In this specification, the maximum height difference of waviness of a film is measured as follows.

[0031] In this specification, the maximum height difference of the waviness is measured using a three-dimensional optical profiler (New View 7200, manufactured by Zygo). Furthermore, MetroPro version 9.0.10 Advanced Texture Application is used as the measurement and analysis software. Furthermore, the analysis conditions are High FFT Filter: Auto, Low FFT Filter: Auto, and Noise Filter Size: 0. In the above analysis, if the AUTO function is not used, the analysis is performed under the conditions of High Filter Wavelen of 330 μm and Low Filter Wavelen of 1020 μm. By removing high-frequency components from the three-dimensional profile obtained by the above analysis, the degree of waviness in the three-dimensional profile can be evaluated. Hereinafter, the surface obtained by removing high-frequency components from the three-dimensional profile will also be referred to as a "waviness surface."

[0032] First, a 10 mm x 10 mm area of ​​the surface of glass (Corning Incorporated, Eagle XG) is measured using the above-mentioned 3D optical profiler, and 3D profiles are obtained at 10 locations while changing the measurement position. Using the above-mentioned analysis software and conditions, a wavy surface is obtained from the 10 3D profiles. The maximum height difference (maximum waviness height difference) of the wavy surface at each of the obtained measurement positions is calculated, and the arithmetic mean value of the maximum waviness height differences at the 10 locations is determined. This average value of the maximum height difference of the glass waviness is designated as Wg (unit: μm). Next, a film is bonded to the glass via an adhesive, Opteria (registered trademark) NCF-D692 (film thickness 15 μm, manufactured by Lintec Corporation). Ten 3D profiles are obtained in the same manner as above for the surface of the film on the side opposite the glass side of the film bonded to the glass, and a wavy surface is obtained for each. Next, the maximum height difference of the undulations of the 10 obtained curved undulation surfaces is calculated, and the arithmetic mean value of the maximum height difference of the undulations is determined. This average value of the maximum height difference of the undulations of the glass is designated as Wf (unit: μm). Here, the "maximum height difference of the undulations" of the film in the present invention refers to the value (unit: μm) obtained by subtracting the above Wg from the above Wf.

[0033] The maximum height difference of the waviness is preferably 1.0 μm or less, more preferably 0.8 μm or less, and even more preferably 0.6 μm or less, in order to further suppress the occurrence of overlapping images when applied to AR glass. The lower limit of the maximum height difference of the waviness is not particularly limited, but is often 0.1 μm or more.

[0034] (Lightly absorbing anisotropic layer) A first embodiment of the film of the present invention includes two lightly absorbing anisotropic layers. Hereinafter, when there is no need to distinguish between the two lightly absorbing anisotropic layers, they may be collectively referred to as "lightly absorbing anisotropic layers." The angle between the central axis of transmittance of the lightly absorbing anisotropic layer and the normal direction of the lightly absorbing anisotropic layer is 0 to 45°, preferably 0° or more and less than 45°, more preferably 0° or more and 35° or less, and even more preferably 0° or more and less than 35°. Note that, from the viewpoint of improving light transmittance, it is preferable that the central axes of transmittance of the two lightly absorbing anisotropic layers are parallel.

[0035] 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.

[0036] -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.

[0037] 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 2013-37353 A, paragraphs

[0049] to

[0073] of JP 2012-63387 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

[0011] to

[0025] paragraphs,

[0017] to

[0069] paragraphs of JP 2011-048311 A,

[0013] to

[0133] paragraphs of JP 2011-213610 A,

[0074] to

[0246] paragraphs of JP 2011-237513 A,

[0005] to

[0051] paragraphs of JP 2016-006502 A,

[0014] to

[0032] paragraphs of JP 2018-053167 A, and

[0014] to

[0033] paragraphs of JP 2020-11716 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, 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.

[0038] 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.

[0039] In the present invention, from the viewpoint of adjusting color hue, it is preferable to use at least one dye compound (first dichroic azo dye compound) having a maximum absorption wavelength in the wavelength range of 560 to 700 nm, and at least one dye compound (second dichroic azo dye compound) having a maximum absorption wavelength in the wavelength range of 455 nm or more and less than 560 nm.

[0040] In the present invention, three or more kinds of dichroic azo dye compounds may be used in combination. For example, in order to make the light absorption anisotropic layer closer to black, it is preferable to use a first dichroic azo dye compound, a second dichroic azo dye compound, and at least one dye compound (third dichroic azo dye compound) having a maximum absorption wavelength in the wavelength range of 380 nm or more and less than 455 nm in combination.

[0041] 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).

[0042] 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.

[0043] 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 a 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.

[0044] 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.

[0045]

[0046] 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.

[0047] 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.

[0048]

[0049] In the above formulas (P1-A) to (P1-D), "*" represents the bonding position with L1 in the above formula (1). １ , R ２ , R ３ and R ４each independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms. The alkyl group may be a linear or branched alkyl group, or an alkyl group having a cyclic structure (a cycloalkyl group). The alkyl group preferably has 1 to 5 carbon atoms. The group represented by formula (P1-A) is preferably a unit of a partial structure of a poly(meth)acrylic acid ester obtained by polymerization of a (meth)acrylic acid ester. The group represented by formula (P1-B) is preferably an ethylene glycol unit formed by ring-opening polymerization of an epoxy group in a compound having an epoxy group. The group represented by formula (P1-C) is preferably a propylene glycol unit formed by ring-opening polymerization of an oxetane group in a compound having an oxetane group. The group represented by formula (P1-D) is preferably a siloxane unit of a polysiloxane obtained by condensation polymerization of a compound having at least one of an alkoxysilyl group and a silanol group. Here, the compound having at least one of an alkoxysilyl group and a silanol group is a compound represented by the formula SiR １４ (OR １５ ) ２ In the formula, R １４ is R in (P1-D) １４ and plural R １５ each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

[0050] In the above formula (1), L1 is a single bond or a divalent linking group. Examples of the divalent linking group represented by L1 include —C(O)O—, —O—, —S—, and —C(O)NR ３ -, -SO ２ - and -NR ３ R ４ In the formula, R ３ and R ４each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent. When P1 is a group represented by formula (P1-A), L1 is preferably a group represented by -C(O)O-, since this will result in a higher degree of orientation of the dichroic material. When P1 is a group represented by formulas (P1-B) to (P1-D), L1 is preferably a single bond, since this will result in a higher degree of orientation of the dichroic material.

[0051] 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.

[0052] 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 "FlussigeKristalle inTablellen II" (VEBDeutsche Verlagfür GrundstoffIndustrie, 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.

[0053] 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).

[0054] T1 is preferably an alkoxy group having 1 to 10 carbon atoms, more preferably an alkoxy group having 1 to 5 carbon atoms, and even more preferably a methoxy group, in that the degree of orientation of the dichroic material is increased. These terminal groups may be further substituted with these groups or with the polymerizable groups described in JP-A-2010-244038.

[0055] 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.

[0056] 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.

[0057] 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)

[0058] 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-2019-73496 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] ).

[0059] 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):

[0060]

[0061] 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)

[0062] 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.

[0063] 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.

[0064] 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.

[0065] Particularly preferred examples of the polymerizable group include those represented by any of the above formulae (P-1) to (P-20).

[0066] 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.

[0067] 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

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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).

[0075] 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.

[0076] 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.

[0077] 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.

[0078] Formula (A)

[0079] 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.

[0080] The onium salt is preferably a compound represented by formula (B).

[0081] Formula (B)

[0082] 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.

[0083] 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.

[0084] 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 (fluorine-based leveling agent) or a leveling agent containing a silicon atom (silicon-based leveling agent) is preferred, with a fluorine-based leveling agent being more preferred.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] -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, as described below, in addition to the dichroic substance and the liquid crystal compound, and may further contain other components as described above.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] -Method for manufacturing an optically absorbing anisotropic layer- The method for manufacturing an optically absorbing anisotropic layer is not particularly limited, but from the viewpoint of achieving a higher degree of orientation of the dichroic material, a method (hereinafter also referred to as "this manufacturing method") that includes, in this 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 "coating film formation step"), and a step of orienting the liquid crystal component contained in the coating film (hereinafter also referred to as "orientation step"). 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.

[0095] 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.

[0096] The alignment film may be any film that aligns the liquid crystal component 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, in the present invention, alignment films formed by rubbing are preferred in terms of ease of control of the pretilt angle of the alignment film, and photo-alignment films formed by light irradiation are also preferred in terms of uniformity of alignment.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] The thickness of the optically absorptive anisotropic layer is not particularly limited, but is preferably from 0.5 to 7 μm, more preferably from 1.0 to 3 μm, in terms of achieving better effects of the present invention.

[0103] (Retardation Layer) The film of the first embodiment of the present invention includes at least one retardation layer between two light absorption anisotropic layers. The film of the first embodiment of the present invention preferably includes two or more retardation layers. The retardation layer is preferably a retardation layer having a slow axis in the in-plane direction, and is preferably a λ / 2 plate. In this specification, the λ / 2 plate refers to a retardation layer having an in-plane retardation of approximately ½ of the wavelength, specifically a retardation layer having an in-plane retardation Re(550) of 220 to 320 nm at a wavelength of 550 nm.

[0104] The material for forming the retardation layer is not particularly limited, and examples thereof include a retardation layer containing a liquid crystal compound and a stretched film. Among these, a retardation layer containing a liquid crystal compound is preferred as the retardation layer.

[0105] 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.

[0106] Preferred rod-shaped liquid crystal compounds include azomethines, azoxy compounds, cyanobiphenyls, cyanophenyl esters, benzoates, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes, and alkenylcyclohexylbenzonitriles. These rod-shaped liquid crystal compounds are fixed by introducing a polymerizable group into the terminal structure of the rod-shaped liquid crystal compound (as with the discotic liquid crystals described below), followed by polymerization and curing. A specific example is described in JP-A No. 2006-209073, in which a polymerizable nematic rod-shaped liquid crystal compound is cured with ultraviolet light. In addition to the low-molecular-weight liquid crystal compounds described above, polymeric liquid crystal compounds can also be used. Polymeric liquid crystal compounds are polymers having side chains corresponding to the low-molecular-weight liquid crystal compounds described above. Optical compensation sheets using polymeric liquid crystal compounds are described in JP-A No. 5-053016, for example.

[0107] Examples of discotic liquid crystal compounds include benzene derivatives described in the research report by C. Destrade et al., Mol. Cryst., Vol. 71, p. 111 (1981), truxene derivatives described in the research report by C. Destrade et al., Mol. Cryst., Vol. 122, p. 141 (1985) and Physicslett, A, Vol. 78, p. 82 (1990), cyclohexane derivatives described in the research report by B. Kohne et al., Angew. Chem., Vol. 96, p. 70 (1984), and compounds described in the research report by J. M. Lehn et al., J. Chem. Commun., p. 1794 (1985), and the research report by J. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994) include azacrown and phenylacetylene macrocycles.

[0108] The discotic liquid crystal compound molecules also include compounds exhibiting liquid crystallinity, which have a structure in which linear alkyl groups, alkoxy groups, or substituted benzoyloxy groups are radially substituted as side chains of 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. Retardation layers formed from compositions containing discotic liquid crystal compounds do not necessarily exhibit liquid crystallinity when ultimately incorporated into the retardation 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, retardation 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.

[0109] In order to fix discotic liquid crystal molecules by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystal molecule. A compound in which the discotic core and the polymerizable group are bonded via a linking group is preferred, and this allows the alignment state to be maintained even during the polymerization reaction. Examples thereof include compounds described in paragraphs

[0151] to

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

[0110] In the film of the first embodiment of the present invention, it is preferred that at least one retardation layer is a layer formed using a composition containing a discotic liquid crystal compound.When two or more retardation layers are included, it is also preferred that at least one retardation layer is a layer formed using a composition containing a discotic liquid crystal compound, and at least one retardation layer is a layer formed using a composition containing a rod-shaped liquid crystal compound.In addition, when two or more retardation layers are included, at least two retardation layers may be layers formed using a composition containing a discotic liquid crystal compound.

[0111] In the film of the first embodiment of the present invention, it is also preferable that at least one of the retardation layers is a layer formed using a composition containing a rod-shaped liquid crystal compound with reverse wavelength dispersion, because it can suppress color change. Note that, as such a rod-shaped liquid crystal compound with reverse wavelength dispersion, there can be mentioned any liquid crystal compound (particularly, a polymerizable liquid crystal compound with reverse wavelength dispersion) described above as being contained in the light absorption anisotropic layer.

[0112] Furthermore, when two or more retardation layers are included, for the reasons of improving the light blocking ability of light incident from an oblique direction and suppressing color change, it is also preferable that at least one retardation layer is a layer formed using a composition containing a rod-shaped liquid crystal compound, and at least one retardation layer other than the layer formed using the composition containing the rod-shaped liquid crystal compound is a layer formed using a composition containing a discotic liquid crystal compound. It is also preferable that at least one retardation layer is a layer formed using a composition containing a rod-shaped liquid crystal compound with reverse wavelength dispersion, and at least one retardation layer other than the layer formed using the composition containing the rod-shaped liquid crystal compound with reverse wavelength dispersion is a layer formed using a composition containing a discotic liquid crystal compound. Note that such rod-shaped liquid crystal compounds and rod-shaped liquid crystal compounds with reverse wavelength dispersion include those described as any liquid crystal compounds contained in the light absorption anisotropy layer above (particularly, polymerizable liquid crystal compounds with reverse wavelength dispersion and polymerizable liquid crystal compounds with forward wavelength dispersion).

[0113] In the film of the first embodiment of the present invention, when the retardation 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, as a method for forming the retardation layer, for example, a method in which a composition containing a liquid crystal compound is used to achieve a desired alignment state and then fixed by polymerization can be mentioned. Here, the polymerization conditions are not particularly limited, but ultraviolet light is preferably used for polymerization by light irradiation. The irradiation dose is 10 mJ / cm. ２ ~50 J / cm ２ is preferred, and 20 mJ / cm ２ ~5 J / cm ２ More preferably, 30 mJ / cm ２ ~3 J / cm ２ is more preferably 50 to 1000 mJ / cm ２ In order to accelerate the polymerization reaction, the reaction may be carried out under heating conditions.

[0114] The thickness of the retardation layer is not particularly limited, but is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and even more preferably 1 to 10 μm.

[0115] In the film of the first embodiment of the present invention, when two retardation layers are included, the light blocking property of light incident from an oblique direction is better, so it is preferable that the two retardation layers are in direct contact with each other or laminated via at least one of the adhesive layer, pressure-sensitive adhesive layer and alignment film described later. Here, "laminated via at least one" means that when there is one of the adhesive layer, pressure-sensitive adhesive layer and alignment film, it is laminated via only one of them, but when there are two of the adhesive layer, pressure-sensitive adhesive layer and alignment film (for example, pressure-sensitive adhesive layer and alignment film), it means that there is laminated via only two of them.

[0116] 1, the angle between the in-plane slow axis direction of the first retardation layer 14a and the in-plane slow axis direction of the second retardation layer 14b is 45°. In the film of the first embodiment of the present invention, when two retardation layers are included, the angle between the in-plane slow axis direction of one retardation layer and the in-plane slow axis direction of the other retardation layer is preferably within the range of 45±10°, more preferably within the range of 45±8°, and even more preferably within the range of 45±5°.

[0117] The retardation layer may include a retardation plate (another retardation plate) other than a λ / 2 plate. A preferred example of the other retardation plate is a positive C plate. The positive C plate refers to an optical member whose refractive indexes nx, ny, and nz satisfy the following formula (2): Formula (2): nz>nx≒ny. For example, when a λ / 2 plate is included as the retardation layer, the positive C plate enables higher optical compensation for light incident from an oblique direction.

[0118] (Alignment Film) In the first embodiment of the film of the present invention, when the above-mentioned light absorption anisotropic layer and retardation 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 rubbing treatment; photo-alignment films of polyvinyl cinnamate and azo dyes, which may or may not have been subjected to polarized light exposure treatment; and the like. The thickness of the alignment film is preferably 0.01 to 10 μm, more preferably 0.01 to 1 μm.

[0119] (Adhesive Layer) The first embodiment of the film of the present invention may have an adhesive layer. The adhesive layer is preferably a transparent, optically isotropic adhesive similar to those used in ordinary image display devices, and a pressure-sensitive adhesive is usually used.

[0120] 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.

[0121] When the first embodiment of the film of the present invention includes a pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer is preferably 20 μm or less, more preferably 10 μm or less, even more preferably 8 μm or less, and particularly preferably 5 μm or less, in that the maximum height difference of the waviness tends to be smaller. The lower limit of the thickness of the pressure-sensitive adhesive layer is not particularly limited, but is often, for example, 0.1 μm or more.

[0122] The storage modulus of the pressure-sensitive adhesive layer is preferably 0.6 MPa to 20 MPa, since this tends to further reduce the maximum height difference of the waviness. The storage modulus of the pressure-sensitive adhesive layer refers to a value measured using a dynamic viscoelasticity measuring device (DVA-200) manufactured by IT Measurement & Control Co., Ltd. under conditions of a frequency of 1 Hz and 25°C.

[0123] The thickness of the first embodiment of the film of the present invention is preferably 50 to 400 μm, since this tends to make the maximum height difference of the waviness smaller.

[0124] In the first embodiment of the film of the present invention, the pressure-sensitive adhesive layer may include two or more layers. For example, in the embodiment shown in Figure 1, the pressure-sensitive adhesive layer may be disposed between the first optically absorptive anisotropic layer 12a and the first retardation layer 14a, between the first retardation layer 14a and the second retardation layer 14b, and between the second retardation layer 14b and the second optically absorptive anisotropic layer 12b, or may be disposed between two of the above three.

[0125] (Adhesive Layer) The film of the first embodiment of the present invention may have an adhesive layer. The adhesive layer exhibits adhesiveness by drying, reaction, etc. after lamination. A polyvinyl alcohol-based adhesive (PVA-based adhesive) exhibits adhesiveness by drying, making it possible to bond materials together.

[0126] 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.

[0127] When the film of the first embodiment of the present invention includes an adhesive layer, the thickness of the adhesive layer is preferably 20 μm or less, more preferably 10 μm or less, even more preferably 8 μm or less, and particularly preferably 5 μm or less, in that the maximum height difference of the waviness tends to be smaller. The lower limit of the thickness of the adhesive layer is not particularly limited, but is often, for example, 0.1 μm or more.

[0128] In the first embodiment of the film of the present invention, two or more adhesive layers may be included. For example, in the embodiment shown in Figure 1, the adhesive layer may be disposed between the first optically absorptive anisotropic layer 12a and the first retardation layer 14a, between the first retardation layer 14a and the second retardation layer 14b, and between the second retardation layer 14b and the second optically absorptive anisotropic layer 12b, or between any two of the above three layers.

[0129] (Antireflection Layer) The film of the first embodiment of the present invention may include an antireflection layer. The antireflection layer is preferably disposed on the outermost side of the first embodiment of the film of the present invention. The type of antireflection layer is not particularly limited, and known antireflection layers such as a dielectric layer, an interference reflection layer formed by alternating stacks of high refractive index materials and low refractive index materials, or a moth-eye structure formed on the surface can be applied. The antireflection layer is preferably an antireflection layer having a moth-eye structure on its surface. An example of a method for providing an antireflection layer is a method in which an antireflection film is attached to the film of the first embodiment of the present invention via an adhesive layer to provide an antireflection layer. The antireflection film is a film having a known antireflection layer.

[0130] The surface reflectance of the first embodiment of the film of the present invention is preferably 5.0% or less, more preferably 3.0% or less, even more preferably 1.0% or less, and particularly preferably 0.5% or less. The lower limit of the surface reflectance is not particularly limited, but is often 0.1% or more. The above surface reflectance can be achieved, for example, by disposing the anti-reflection layer on one side of the first embodiment of the film of the present invention. The surface reflectance is measured using the following method. Specifically, a black PET film (trade name "Kukkiri Miel", manufactured by Tomoegawa Paper Co., Ltd.) is attached to the surface opposite to the surface for which the surface reflectance is to be measured, and the specular reflectance is measured using a spectrophotometer. The spectrophotometer used is a V-750 equipped with the option ARV-474 (both manufactured by JASCO Corporation). The measurement conditions are as follows: ・Angle of incidence: 5° ・Acceptance angle: 5° ・Wavelength range: 380 to 780 nm

[0131] (Other Layers) The first embodiment of the film of the present invention may have layers (other layers) other than those described above. Examples of the other layers include a protective layer, an oxygen barrier layer, an ultraviolet absorbing layer, and a blue light absorbing layer.

[0132] (Manufacturing Method) The manufacturing method of the first embodiment of the film of the present invention is not particularly limited. For example, a method can be used in which an optically absorbing anisotropic layer (first optically absorbing anisotropic layer 12a), a retardation layer (first retardation layer 14a and second retardation layer 14b), and an optically absorbing anisotropic layer (second optically absorbing anisotropic layer 12b) are formed, and then these layers are bonded together with a pressure-sensitive adhesive layer or an adhesive layer. It is preferable that the first embodiment of the film of the present invention obtained by bonding with a pressure-sensitive adhesive layer as described above is further subjected to heat treatment. By performing heat treatment, air bubbles and the like that may occur during bonding with the pressure-sensitive adhesive layer can be removed, and the maximum height difference of the waviness tends to be reduced. Furthermore, pressure treatment may be performed simultaneously with the heat treatment. By performing pressure treatment, air bubbles and the like that may occur during bonding with the pressure-sensitive adhesive layer can be easily removed. Furthermore, the heat treatment may be performed when bonding is performed. Furthermore, when bonding is performed, the pressure treatment may be performed simultaneously with the heat treatment. Examples of the heat treatment include autoclave treatment, infrared heat treatment, heat press treatment, and heat lamination treatment.

[0133] [Second Embodiment] A second embodiment of the film of the present invention includes an optically absorptive anisotropic layer and a polarizer. The angle between the central axis of transmittance of the optically absorptive anisotropic layer and the normal direction of the optically absorptive anisotropic layer is 0 to 45°. The maximum height difference of the waviness in a 10 mm × 10 mm region on the film surface is 1.2 μm or less.

[0134] Fig. 2 is a schematic diagram showing an example of a second embodiment of the film of the present invention. Film 10B shown in Fig. 2 has an optically absorptive anisotropic layer 12 and a polarizer 16. The optically absorptive anisotropic layer 12 shown in Fig. 2 has an angle of 0° between the transmittance central axis and the normal direction of the optically absorptive anisotropic layer 12 (corresponding to the black double-headed arrow in the optically absorptive anisotropic layer 12 in Fig. 2). In addition, in the embodiment shown in Fig. 2, polarizer 16 has an absorption axis in a direction perpendicular to the left-right direction of the paper (corresponding to the black double-headed arrow in the polarizer 16 in Fig. 2).

[0135] In the film of the second embodiment having the configuration shown in Fig. 2 , light incident in the direction of the central transmittance axis of the optically absorptive anisotropic layer 12 (the direction indicated by the solid arrow in Fig. 2 ) is transmitted through the optically absorptive anisotropic layer 12. Of the light transmitted through the optically absorptive anisotropic layer 12, a portion is transmitted through the polarizer 16, although a portion of the polarized light component vibrating in a direction perpendicular to the left-to-right direction of the page is absorbed by the polarizer 16. On the other hand, for light incident in a direction tilted from the central transmittance axis (the direction indicated by the hollow arrow in Fig. 2 ), a component vibrating in the in-plane direction containing the tilted direction and the central transmittance axis (hereinafter referred to as "P-polarized light") is partially absorbed by the optically absorptive anisotropic layer 12, while a component vibrating in a direction perpendicular to the P-polarized light (hereinafter referred to as "S-polarized light") is transmitted through the optically absorptive anisotropic layer 12 without being substantially absorbed. As a result, when light incident from a direction tilted from the central transmittance axis passes through the optically absorptive anisotropic layer 12, it becomes light with a large S-polarized component. Here, in FIG. 2 , the plane including the direction tilted from the central transmittance axis and the central transmittance axis is perpendicular to the absorption axis direction of the polarizer 16. In the embodiment shown in FIG. 2 , the S-polarized component of the light transmitted through the optically absorptive anisotropic layer 12 is absorbed by the polarizer 16 because the absorption axis direction of the polarizer 16 and the vibration direction of the S-polarized light are approximately identical. As described above, in the embodiment shown in FIG. 2 , light incident from a direction tilted from the central transmittance axis at a predetermined azimuth angle is absorbed by the optically absorptive anisotropic layer 12 or the polarizer 16. On the other hand, a portion of the light incident from the central transmittance axis direction is transmitted without being absorbed. Therefore, when applied to AR glasses, the embodiment shown in FIG. 2 functions as a filter that has high transmittance for light incident from the central transmittance axis direction (e.g., the viewing direction) and low transmittance for light incident from an oblique direction. Such a filter can prevent external light from entering the diffraction element provided in the AR glass from an oblique direction, and therefore can suppress rainbow unevenness when applied to the AR glass.

[0136] 2, for light incident from a direction tilted from the central transmittance axis within a plane parallel to the absorption axis direction and the central transmittance axis of the polarizer 16, the S-polarized component is transmitted without being absorbed by the polarizer 16. Therefore, the direction of the absorption axis of the polarizer 16 can be appropriately adjusted depending on the direction of light to be blocked. A second embodiment of the film of the present invention will now be described in detail.

[0137] (Maximum height difference of waviness) As described above, in the second embodiment of the film of the present invention, the maximum height difference of waviness in a 10 mm x 10 mm area is 1.2 μm or less. The maximum height difference of waviness of the film of the present invention is the same as that of the first embodiment, including preferred embodiments, and therefore will not be described further.

[0138] (Lightly absorbing anisotropic layer) A second embodiment of the film of the present invention includes an optically absorbing anisotropic layer. The angle between the transmittance central axis of the optically absorbing anisotropic layer and the normal direction of the optically absorbing anisotropic layer is 0 to 45°. The optically absorbing anisotropic layer in the second embodiment of the film of the present invention is the same as the optically absorbing anisotropic layer in the first embodiment, including preferred embodiments thereof, and therefore will not be described here.

[0139] (Polarizer) A second embodiment of the film of the present invention includes a polarizer. The polarizer is preferably a linear polarizer having an absorption axis in the in-plane direction. Known linear polarizers can be used. Examples of linear polarizers include absorptive polarizers containing iodine compounds and reflective polarizers such as wire grids. The polarization axis is synonymous with the transmission axis. Examples of absorptive polarizers that can be used include iodine-based polarizers, dye-based polarizers using dichroic dyes, and polyene-based polarizers. Iodine-based polarizers and dye-based polarizers are generally produced by adsorbing iodine or a dichroic dye to polyvinyl alcohol and stretching the resulting film. It is also possible to use a linear polarizer in which the above-mentioned dichroic dye is oriented in the in-plane direction.

[0140] (Pressure-sensitive adhesive layer and adhesive layer) The second embodiment of the film of the present invention may include at least one of a pressure-sensitive adhesive layer and an adhesive layer. The pressure-sensitive adhesive layer and adhesive layer in the second embodiment of the film of the present invention are the same as the pressure-sensitive adhesive layer and adhesive layer in the first embodiment, including preferred aspects, and therefore will not be described here.

[0141] (Retardation Layer) The second embodiment of the film of the present invention may include a retardation layer. In the second embodiment of the film of the present invention, the retardation layer is preferably disposed between the light absorption anisotropic layer and the polarizer. A suitable example of the retardation layer is a B plate. The B plate refers to a biaxial optical element in which the refractive indexes nx, ny, and nz are different from each other.

[0142] The Re (in-plane retardation) of the B plate is greater than 80 nm and less than 250 nm, more preferably 100 nm or more and less than 250 nm, and even more preferably 100 nm or more and 200 nm or less. The Nz coefficient of the B plate is preferably greater than 1.5, more preferably 2.0 or more and 10.0 or less, and even more preferably 3.0 or more and 5.0 or less. The Nz coefficient is a value calculated by Nz = (nx - nz) / (nx - ny). The Rth of the B plate is preferably set so as to satisfy the above-mentioned preferred ranges for the Re and Nz coefficients, and specifically, is preferably greater than 60 nm. The slow axis of the B plate preferably has an azimuthal angle (the angle with the absorption axis of the polarizer) of -10 to 10°, more preferably -5 to 5°, and most preferably 0° (i.e., parallel to the absorption axis of the polarizer), when the direction of the absorption axis of the polarizer is taken as 0°. That is, the angle between the slow axis of the B plate and the absorption axis of the polarizer is preferably 10° or less, more preferably 5° or less, and most preferably 0°. When the optical properties of the B plate are within the above ranges, when the film is viewed obliquely in an orientation that is neither horizontal nor vertical to the absorption axis of the polarizer in the plane of the film, deviation of the polarizer absorption axis from the perpendicular can be compensated for, and the transmittance in that direction can be reduced.

[0143] In the optical filter of the present invention, a combination of a positive A plate and a positive C plate is also a suitable example of the retardation layer. That is, a laminate in which a positive A plate and a positive C plate are laminated is also a suitable example of the retardation layer. Here, the positive A plate refers to an optical member in which the refractive indexes nx, ny, and nz satisfy the following formula (1): Formula (1): nx>ny≒nz. Furthermore, the positive C plate refers to an optical member in which the refractive indexes nx, ny, and nz satisfy the above formula (2).

[0144] The Re of the laminate of the positive C plate and the positive A plate is preferably greater than 80 nm and less than 250 nm, more preferably 100 to 200 nm, and even more preferably 100 to 150 nm. Since the Re of the positive C plate is approximately 0, the Re of the laminate of the positive C plate and the positive A plate is substantially the same as the Re of the positive A plate, and the slow axis of the laminate of the positive C plate and the positive A plate is substantially the same as the slow axis of the positive A plate. The slow axis of the positive A plate preferably has an azimuth angle of 80 to 100°, more preferably 85 to 95°, and even more preferably 90° (i.e., perpendicular to the absorption axis of the polarizer). That is, the angle between the slow axis of the positive A plate and the absorption axis of the polarizer is preferably 80 to 100°, more preferably 85 to 95°, and even more preferably 90°. The Rth of the laminate of the positive C plate and the positive A plate is preferably smaller than −60 nm, more preferably −600 to −100 nm, and even more preferably −500 to −200 nm. Since the Rth of the positive A plate is approximately equal to Re / 2, the Rth of the laminate of the positive C plate and the positive A plate is the sum of the Rth of the positive A plate and the positive C plate. When the optical properties of the positive C plate and the positive A plate are within the above ranges, when the film is viewed obliquely in an orientation that is neither horizontal nor vertical to the absorption axis of the polarizer in the plane of the film, deviation of the polarizer absorption axis from the perpendicular can be compensated for, and the transmittance in that direction can be reduced.

[0145] In addition, it is also preferable that the wavelength dispersion of Re and Rth of the positive C plate and the positive A plate are reverse dispersion. More specifically, it is preferable that the wavelength dependency of the retardation layer satisfies Re(450 nm)<Re(550 nm)<Re(650 nm) or Rth(450 nm)<Rth(550 nm)<Rth(650 nm).

[0146] (Alignment film) The second embodiment of the film of the present invention may include an alignment film. The aspects of the alignment film in the second embodiment of the film of the present invention are the same as those in the first embodiment, including preferred aspects, and therefore will not be described further.

[0147] (Antireflection layer) The second embodiment of the film of the present invention may include an antireflection layer. The aspects of the antireflection layer in the second embodiment of the film of the present invention are the same as those in the first embodiment, including preferred aspects, and therefore will not be described further.

[0148] The surface reflectance of the second embodiment of the film of the present invention is the same as that of the first embodiment, including preferred embodiments, and therefore will not be described further. The second embodiment of the film of the present invention may also have other layers as described in the first embodiment of the film of the present invention.

[0149] <Optical Member> The optical member of the present invention includes the film of the present invention (first embodiment and second embodiment) and a transparent support. Hereinafter, the transparent support and configurations that the optical member of the present invention may have will be described.

[0150] [Transparent Support] The optical member of the present invention includes a transparent support. In the embodiment shown in Figure 3 described later, the transparent support included in the optical member is a cover glass, but the transparent support is not particularly limited as long as it can support the film of the present invention, and any known transparent support can be used. Note that 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.

[0151] The material constituting the transparent support may be an organic substance such as a polymer, or an inorganic substance such as glass. Examples of the polymer constituting the transparent support include cellulose-based polymers; acrylic polymers having acrylic acid ester polymers such as polymethyl methacrylate and lactone ring-containing polymers; thermoplastic norbornene-based polymers; polycarbonate-based polymers; polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate; styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymers; polyolefin-based polymers such as polyethylene, polypropylene, and ethylene-propylene copolymers; vinyl chloride-based polymers; amide-based polymers such as nylon and aromatic polyamides; imide-based polymers; sulfone-based polymers; polyethersulfone-based polymers; polyetheretherketone-based polymers; polyphenylene sulfide-based polymers; vinylidene chloride-based polymers; vinyl alcohol-based polymers; vinyl butyral-based polymers; arylate-based polymers; polyoxymethylene-based polymers; epoxy-based polymers; and polymers containing mixtures of these polymers. Conventional known glass can be used as the glass constituting the transparent support.

[0152] The maximum height difference of the undulations on the side of the transparent support where the film is placed is preferably 0.8 μm or less, more preferably 0.6 μm or less, in order to further suppress the occurrence of overlapping images when the optical element is applied to AR glass. The lower limit of the maximum height difference of the undulations on the side of the transparent support where the film is placed is not particularly limited, but is often 0.01 μm or more. The maximum height difference of the undulations of the transparent support can be obtained by the same method as the method for measuring the average value Wg of the maximum height difference of the undulations of the above-mentioned film.

[0153] The transparent support may have a protective layer on the surface opposite to the side on which the film of the present invention is provided. The protective layer preferably has high surface hardness and functions to prevent the surface of the transparent support from being scratched when another object comes into contact with the transparent support.

[0154] The shape of the transparent support is not particularly limited. It may be a long shape or a shape suitable for a head-mounted display. The transparent support may be flat or may have a curved surface. When the transparent support is not flat, the entire shape of the transparent support is removed when analyzing the maximum height difference of the waviness, and the maximum height difference of the waviness can be calculated.

[0155] [Pressure-sensitive adhesive layer and adhesive layer] The optical member of the present invention may include a pressure-sensitive adhesive layer or an adhesive layer between the transparent support and the film of the present invention. The pressure-sensitive adhesive layer and adhesive layer that the optical member may include are the same as the pressure-sensitive adhesive layer and adhesive layer of the film of the present invention (first embodiment and second embodiment), and therefore description thereof will be omitted.

[0156] When the film of the present invention (the first and second embodiments described above) includes an antireflection layer, the antireflection layer is preferably provided on the side opposite to the transparent support side.

[0157] <Optical device and head-mounted display> The optical device of the present invention includes the optical element of the present invention and a light guide plate having a diffraction element disposed on its surface, the optical element being disposed at a distance from the light guide plate. Furthermore, the head-mounted display of the present invention includes the optical device of the present invention and an image display element. Hereinafter, the head-mounted display of the present invention including the optical element of the present invention will be described with reference to the drawings.

[0158] 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 40 shown in FIG. 3 include an optical device 30 and an image display element 42 that transmits image light L1 to the optical device. The optical device 30C includes a light guide plate 32 and an incident diffraction element 34 and an exit diffraction element 36 that are disposed on the side of the light guide plate 32 opposite the image display element 42 side. The optical device 30 also includes an optical element 20 that includes a cover glass 22 and a film 10. In the optical element 20, the film 10 is disposed on the light guide plate 32 side. The film 10 is disposed at a distance from the incident diffraction element 34 and the exit diffraction element 36. The optical device 30 shown in FIG. 3 is an optical device of the present invention that includes the film of the present invention.

[0159] The arrangement position of the incident diffraction element 34 corresponds to the incident position of the image light L1 from the image display element 42. The arrangement position of the output diffraction element 36 corresponds to the output position of the image light L1 from the light guide plate 32, i.e., the position at which the image light L1 is observed by the user. The incident diffraction element 34 diffracts the image light L1 that enters the light guide plate 32 from the image display element 42, into the light guide plate 32. The diffracted image light L1 travels in the in-plane direction of the light guide plate 32 while being totally reflected within the light guide plate 32. The output diffraction element 36 diffracts the light propagating within the light guide plate 32 toward the user.

[0160] As described above, in the output diffraction element 36 of such AR glasses 40, a portion of the image light L1 may be emitted on the side opposite the user (toward the optical member 20), generating stray light Ls. Even when such stray light Ls occurs, since the maximum height difference of the undulations of the film 10 (the film of the present invention) is equal to or less than a predetermined value, the stray light Ls is reflected in a direction parallel to the image light L1, and it is therefore thought that overlapping images are unlikely to occur.

[0161] The light guide plate 32 included in the optical device 30 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.

[0162] The incident diffraction element 34 and the exit diffraction element 36 included in the optical device 30 are transmissive diffraction elements, and the scenery on the backside can be simultaneously viewed through the incident diffraction element 34 and the exit diffraction element 36. 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 34 and the exit diffraction element 36 may be a reflective diffraction element.

[0163] The image display element 42 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 86 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 86 may display monochrome images, two-color images, or color images.

[0164] 3 may have an intermediate diffraction element in addition to the incident diffraction element 34 and the exit diffraction element 36. 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 in the direction in which the exit diffraction element 36 is disposed. Diffraction elements similar to the incident diffraction element 34 and the exit diffraction element 36 can be used as the intermediate diffraction element.

[0165] 3, the film 10 is disposed on the light guide plate 32 side of the optical element 20 included in the optical device 30, but the film 10 may be disposed on the opposite side of the optical element 20 included in the optical device 30 from the light guide plate 32 side. That is, the cover glass 22 (transparent support) in the optical element 20 may be disposed on the light guide plate 32 side. By adopting the above-described configuration, stray light Ls is less likely to be reflected by the film 10, and the occurrence of overlapping images can be further suppressed.

[0166] Furthermore, because the film (film 10) of the present invention can suppress rainbow unevenness, rainbow unevenness is suppressed in the head-mounted display (AR glasses 40) of the present invention that includes the film of the present invention. In the optical device 30, the optical element 20 is preferably arranged so as to overlap at least the area corresponding to the portion where the incident diffraction element 34 and the exit diffraction element 36 are arranged on the light guide plate 32. By arranging the optical element 20 so as to overlap the above-mentioned area, it becomes difficult for external light to be incident on the incident diffraction element 34 and the exit diffraction element 36 from an oblique direction, and the occurrence of rainbow unevenness can be further suppressed.

[0167] 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.

[0168] Example 1 A film 1 was obtained by the following procedure, and a head-mounted display (AR glasses) A1 used in Example 1 was fabricated.

[0169] [Preparation of Optically Absorbent Anisotropic Layer] An optically absorptive anisotropic layer was prepared according to the following procedure.

[0170] (Formation of alignment film) The surface of a 40 μm-thick cellulose acylate film (TAC substrate; manufactured by Fujifilm Corporation, TG40) was saponified with an alkaline solution, and the following alignment film-forming composition 1 was applied thereon with 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 an alignment film AL1, thereby obtaining a cellulose acylate film 1 with an alignment film. The thickness of the alignment film AL1 was 1 μm.

[0171] ------------------------------------------------------------------ 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 ------------------------------------------------------------------

[0172] Modified polyvinyl alcohol PVA-1

[0173] (Formation of Optically Absorbent Anisotropic Layer V1) The following composition for forming an optically absorbent anisotropic layer P1 was continuously applied onto the obtained cellulose acylate film 1 with an alignment layer using a wire bar, heated at 120°C for 60 seconds, and then cooled to room temperature (23°C). Next, the composition was heated at 85°C for 60 seconds and cooled again to room temperature. Thereafter, an LED lamp (center wavelength 365 nm) was used to illuminate the layer from the direction normal to the film at an illuminance of 200 mW / cm. ２ The optically absorptive anisotropic layer V1 was formed on the alignment film AL1 by irradiating the alignment film AL1 with light for 2 seconds under the irradiation conditions of 1. The thickness of the optically absorptive anisotropic layer V1 was 2.7 μm.

[0174] 0.17 parts by mass of dichroic substance D-2 below; 1.13 parts by mass of dichroic substance D-3 below; 8.67 parts by mass of polymer liquid crystal compound P-1 below; 1.97 parts by mass of liquid crystal compound L-1 below; 0.20 parts by mass of IRGACURE OXE-02 (manufactured by BASF); 0.16 parts by mass of alignment agent E-1 below; 0.16 parts by mass of alignment agent E-2 below; 0.012 parts by mass of surfactant F-1 below; 78.17 parts by mass of cyclopentanone; 8.69 parts by mass of benzyl alcohol ----------------------------------------------------------------------------------

[0175] Dichroic substance D-1

[0176] Dichroic substance D-2

[0177] Dichroic substance D-3

[0178] Polymer liquid crystal compound P-1

[0179] 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]

[0180] Orientation agent E-1

[0181] Orientation agent E-2

[0182] Surfactant F-1 (In the following formula, TMS represents a trimethylsilyl group.)

[0183] (Formation of Protective Layer H1) The following protective layer-forming composition B1 was continuously applied to the obtained optically absorbing anisotropic layer V1 using a wire bar to form a coating film. The support on which the coating film had been formed was then dried with hot air at 60°C for 60 seconds and then with hot air at 100°C for 120 seconds to form a protective layer H1, thereby producing an optical film Vf having an optically absorbing anisotropic layer V1. The thickness of the protective layer was 0.5 μm. Furthermore, the angle between the transmittance central axis of the optically absorbing anisotropic layer V1 and the normal direction of the optically absorbing anisotropic layer V1 was measured using the procedure described above, and was found to be 0°.

[0184] -------------------------------------------------- Protective layer forming composition B1 -------------------------------------------------- 3.80 parts by mass of modified polyvinyl alcohol PVA-1 shown below 0.20 parts by mass IRGACURE 2959 0.08 parts by mass of dye compound G-1 shown below Water 70 parts by mass Methanol 30 parts by mass --------------------------------------------------

[0185] Modified polyvinyl alcohol PVA-1

[0186] Dye compound G-1

[0187] [Preparation of Retardation Layer] A retardation layer was prepared by the following procedure. (Formation of Alignment Film 2) The following alignment film-forming composition 2 was continuously applied to one side of a 40 μm-thick cellulose acylate film (TAC substrate; manufactured by Fujifilm Corporation, TG40) using a #14 wire bar. After application, the film was dried with hot air at 60° C. for 60 seconds and then with hot air at 100° C. for 120 seconds.

[0188] -------------------------------------------------- Composition of composition 2 for forming alignment film ------------------------------------------------------------------ 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

[0189] (Formation of λ / 2 Layer) The prepared alignment film 2 was continuously subjected to rubbing treatment. At this time, the longitudinal direction of the long film was parallel to the conveyance direction, and the angle between the longitudinal direction of the film and the rotation axis of the rubbing roller was 90° (the film width direction was 0°, the film longitudinal direction was 90°, and when observed from the alignment film side, the clockwise direction with the film width direction as the reference is represented as a positive value, so the rotation axis of the rubbing roller was 0°).

[0190] A retardation layer coating solution containing a discotic liquid crystal compound of the following composition was continuously applied to the above-prepared alignment film 2 using a #5.0 wire bar to prepare a λ / 2 layer. The film conveying speed (V) was 26 m / min. To dry the solvent in the coating solution and ripen the alignment of the discotic liquid crystal compound, the film was heated with 130°C hot air for 90 seconds, followed by 100°C hot air for 60 seconds, and then irradiated with UV at 80°C to fix the alignment of the liquid crystal compound, thereby obtaining an optical film Rf having a λ / 2 layer. The thickness of the λ / 2 layer was 2.2 μm, and the Re at 550 nm was 270 nm. The average tilt angle of the discotic liquid crystal compound's disc surface relative to the film surface was 90°, confirming that the discotic liquid crystal compound was aligned perpendicular to the film surface. In addition, the angle of the slow axis of the λ / 2 layer was parallel to the rotation axis of the rubbing roller, and when the width direction of the film was set to 0° (the longitudinal direction was 90°), the slow axis was 0° when viewed from the λ / 2 layer side.

[0191] ------------------------------------------------ Composition of retardation layer coating liquid -------------------------------------------------- 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-3 below 0.05 parts by mass of alignment film interface aligning agent-4 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 --------------------------------------------------

[0192] Discotic Liquid Crystal-1

[0193] Discotic Liquid Crystal-2

[0194] Alignment film interface alignment agent-3

[0195] Alignment film interface alignment agent-4

[0196] Surfactant F-2

[0197] [Preparation of Film 1] The surface of the optical film Vf having the optically absorptive anisotropic layer V1 on which the protective layer H1 was formed was bonded to the surface of the optical film Rf having the λ / 2 plate on the cellulose acylate film side using a pressure-sensitive adhesive layer (Opteria (registered trademark) NCF-D692 (film thickness: 15 μm, manufactured by Lintec Corporation)). Furthermore, an optical film Rf having a λ / 2 layer separate from the bonded optical film Rf was prepared, and the surface of the λ / 2 layer side was bonded to the surface of the λ / 2 layer side bonded by the above procedure using the pressure-sensitive adhesive layer. When the λ / 2 layers were bonded, they were bonded so that the angle between the in-plane slow axis of one λ / 2 layer and the in-plane slow axis of the other λ / 2 layer was 45°. Next, an optical film Vf having a light absorption anisotropic layer V1 different from the laminated optical film Vf was prepared, and the surface of the optical film Vf on which the protective layer H1 was formed was laminated to the surface of the optical film Rf already laminated on the cellulose acylate film side using the above-mentioned pressure-sensitive adhesive layer. After lamination, the optical film Vf was further treated for 30 minutes under conditions of 50°C and 5 atmospheres using an autoclave (Model: PTU507H, manufactured by HIRAYAMA MFG. CORP.), thereby obtaining film 1. Film 1 had optical film Vf, optical film Rf, optical film Rf, and optical film Vf in this order, and the optical films were laminated together using the above-mentioned pressure-sensitive adhesive layer (see the table below).

[0198] [Measurement of maximum height difference of waviness] The maximum height difference of waviness of the prepared film 1 was measured using the procedure described above. The average value (Wg) of the maximum height difference of waviness of the glass to which film 1 was attached was 0.4 μm. The measurement results are shown in the table below.

[0199] [Measurement of Surface Reflectance] The surface reflectance of the prepared film 1 was measured according to the procedure described above. The surface reflectance of the cellulose acylate film was 4.0%.

[0200] [Preparation of Optical Member O1] The above film 1 and glass (Eagle XG, manufactured by Corning Incorporated) were bonded together with the same pressure-sensitive adhesive layer as above to obtain an optical member O1.

[0201] [Fabrication of Head-Mounted Display A1] The cover glass (on the right eye side) on the side where the light guide plate of VUZIX BLADE 2 SMART GLASSES (manufactured by Vuzix Corporation) was disposed was removed. Subsequently, the optical member O1 was placed in the location where the cover glass had been removed so that the film 1 side of the optical member O1 faced the light guide plate side, thereby obtaining the head-mounted display A1.

[0202] Example 2 A film 2 was obtained by the following procedure, and a head-mounted display A2 was fabricated.

[0203] [Preparation of Polarizing Plate] A polarizing plate having a polarizer thickness of 8 μm and one surface of the polarizer exposed was obtained in the same manner as in the preparation of Polarizing Plate 02 with a protective film on one side described in WO 2015 / 166991.

[0204] [Preparation of Film 2] The polarizer-side surface of the polarizing plate and the surface of the optically absorptive anisotropic layer V1 on which the protective layer H1 was formed were bonded together using the pressure-sensitive adhesive layer to obtain Film 2. In addition, autoclave treatment was carried out using the same procedure as in obtaining Film 1.

[0205] [Preparation of Head-Mounted Display A2] An optical member O2 was obtained in the same manner as in Example 1, except that the film 1 used in preparing the optical member O1 in Example 1 was changed to the film 2 described above, and thus a head-mounted display A2 was obtained.

[0206] Example 3 A film 3 was obtained by the following procedure, and a head-mounted display A3 was fabricated.

[0207] [Preparation of Antireflection Film] An antireflection film having a three-layer antireflection layer on its surface was prepared using a 40 μm-thick cellulose acylate film (TAC substrate; manufactured by Fujifilm Corporation, TG40) as a substrate, with reference to Example 1 Antireflection Film No. 1 in JP-A 2008-262187. The surface reflectance of the prepared antireflection film on the side opposite to the substrate was measured by the above-mentioned method, and was found to be 0.4%.

[0208] [Preparation of Film 3] One surface of Film 1 obtained in Example 1 was bonded to the substrate side surface of the antireflection film using the pressure-sensitive adhesive layer to obtain Film 3. In addition, autoclave treatment was carried out using the same procedure as in obtaining Film 1.

[0209] [Fabrication of Head Mounted Display A3] An optical member O3 and a head mounted display A2 were obtained in the same manner as in Example 1, except that the film 1 used in fabricating the optical member O1 in Example 1 was changed to the film 3. When fabricating the optical member O3, one surface of the glass was bonded to the surface of the film 3 opposite to the anti-reflection film side.

[0210] Example 4 A film 4 was obtained by the following procedure, and a head-mounted display A4 was fabricated.

[0211] [Preparation of Film 4] Film 4 was prepared in the same manner as in the preparation of Film 1, except that the thickness of the pressure-sensitive adhesive layer (thickness: 15 μm) used in the preparation of Film 1 was changed to 5 μm.

[0212] [Preparation of head-mounted display A4] Optical member O4 was obtained in the same manner as in Example 1, except that film 1 used in preparing optical member O1 in Example 1 was changed to film 4, and the thickness of the adhesive layer used for bonding to glass was changed to 5 μm, and thus head-mounted display A4 was obtained.

[0213] Example 5 A head-mounted display A5 was fabricated in the following manner.

[0214] [Fabrication of head-mounted display A5] Head-mounted display A5 was obtained in the same manner as head-mounted display A1, except that in the fabrication of head-mounted display A1 obtained in Example 1, when positioning optical member O1, the glass side of optical member O1 was positioned on the light guide plate side.

[0215] Example 6 A film 6 was obtained by the following procedure, and a head-mounted display A6 was fabricated.

[0216] [Preparation of Retardation Layer B] The retardation layer B was prepared by the following procedure. (Extrusion molding) A 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 to obtain an unstretched film. 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. The melt extrusion was carried out by extrusion from a T-die with a width of 1000 mm and a lip gap of 1 mm, and cast onto three consecutive cast rolls set at 180 ° C., 175 ° C., and 170 ° C. to obtain an unstretched film.

[0217] (Stretching and Heat Fixation) The unstretched film being transported was subjected to a stretching step by the following method.

[0218] The unstretched film was longitudinally stretched using a roll-to-roll longitudinal stretching machine having an aspect ratio (L / W) of 0.2 under the following conditions while being conveyed: -Conditions- Preheating temperature: 175°C Stretching temperature: 175°C Stretching ratio: 90%

[0219] The obtained stretched film had an Re of 270 nm at 550 nm, an Rth of 140 nm, and a film thickness of 35 μm. The stretched film obtained by the above procedure was used as retardation layer B. In the tables below, this is referred to as "λ / 2 layer B".

[0220] [Preparation of Pressure-Sensitive Adhesive Layer D] An acrylate-based polymer was prepared by the following procedure, and pressure-sensitive adhesive layer D was produced. 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 prepare a reaction solution with a solids concentration of 30% by mass. The reaction solution was reacted at 60°C for 4 hours under a nitrogen gas flow 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 the refractive index was found to be 1.52.

[0221] Next, a pressure-sensitive adhesive layer D was produced using the obtained acrylate polymer 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 to obtain a pressure-sensitive adhesive layer-forming coating liquid. The pressure-sensitive adhesive layer-forming coating liquid 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 D. The thickness of the pressure-sensitive adhesive layer D was 15 μm.

[0222] [Preparation of Film 6] Film 6 was obtained in the same manner as Film 3, except that the pressure-sensitive adhesive layer (film thickness: 15 μm) used in the preparation of Film 3 was changed to Pressure-sensitive Adhesive Layer D and the retardation layer was changed to Retardation Layer B.

[0223] [Preparation of head-mounted display A6] Optical member O6 was obtained in the same manner as in Example 1, except that film 1 used in preparing optical member O1 in Example 1 was changed to film 6, and the adhesive layer used for bonding to glass was changed to adhesive layer D, and thus head-mounted display A6 was obtained.

[0224] Comparative Example 1 A film C1 was obtained by the following procedure, and a head-mounted display B1 of Comparative Example 1 was fabricated.

[0225] [Preparation of Film C1] Film C1 was obtained in the same manner as Film 1, except that the pressure-sensitive adhesive layer (film thickness: 15 μm) used in the preparation of Film 1 was changed to pressure-sensitive adhesive layer C (SK2057 (film thickness: 25 μm, manufactured by Soken Chemical & Engineering Co., Ltd.)). Note that the above-mentioned autoclave treatment was not performed when preparing Film C1.

[0226] [Preparation of head-mounted display B1] An optical element OC1 was obtained in the same manner as in Example 1, except that the film 1 used in preparing the optical element O1 in Example 1 was changed to the above-mentioned film C1, and the adhesive layer used for bonding to the glass was changed to the above-mentioned adhesive layer C, and thus a head-mounted display B1 was obtained.

[0227] The films obtained in each of the Examples and Comparative Examples were subjected to measurement of the maximum waviness height difference and the surface reflectance in the same manner as in Example 1.

[0228] <Evaluation of Overlapping Images> The head-mounted displays of each Example and Comparative Example were evaluated for overlapping images. Specifically, an image was displayed on the head-mounted display, and the visibility of the image was evaluated based on the following criteria. The evaluation results are shown in the table below. Note that, from a practical standpoint, an A rating, a B rating, or a C rating is preferable, with an A rating or a B rating being more preferable, and an A rating being even more preferable. A: The displayed image does not appear overlapping, and the image can be clearly recognized. B: A faint image is visible overlapping at a position slightly shifted from the main image, which is slightly bothersome. C: A slightly visible image is visible overlapping at a position slightly shifted from the main image, which is slightly bothersome. D: An image appears overlapping at a position slightly shifted from the main image, which is very bothersome.

[0229] <Results> The configuration, measurement results, and evaluation of the head-mounted displays of each example and comparative example are shown in Table 1. Note that for each configuration, the alignment film, protective layer, cellulose acylate film, and other substrates are omitted.

[0230]

[0231] The results shown in Table 1 confirmed that when a film having a maximum waviness height difference of 1.2 μm or less in a 10 mm × 10 mm region on the film surface was applied to AR glass, the occurrence of overlapping images was suppressed (Examples 1 to 6). On the other hand, the results shown in Table 1 confirmed that when the maximum waviness height difference exceeded 1.2 μm, the occurrence of overlapping images could not be suppressed when the film was applied to AR glass (Comparative Example 1). A comparison of Example 1 and Example 3 confirmed that the occurrence of overlapping images was further reduced when the film further contained an anti-reflection layer disposed on the outermost side. A comparison of Example 1 and Example 4 confirmed that the occurrence of overlapping images was further reduced when the film further contained one or more layers selected from the group consisting of a pressure-sensitive adhesive layer having a thickness of 10 μm or less and an adhesive layer having a thickness of 10 μm or less. A comparison of Example 1 and Example 5 confirmed that the occurrence of overlapping images was further reduced when the transparent support (glass) in the optical component was positioned closer to the light guide plate than the film.

[0232] 10, 10A, 10B, 10C Film 12 Optically absorptive anisotropic layer 12a First optically absorptive anisotropic layer 12b Second optically absorptive anisotropic layer 14a First retardation layer 14b Second retardation layer 16 Polarizer 20, 20C Optical member 22 Cover glass (transparent support) 30, 30C Optical device 32 Light guide plate 34 Incident diffraction element 36 Outgoing diffraction element 40, 40C AR glasses (head-mounted display)

Claims

1. A film comprising at least one optically absorptive anisotropic layer, wherein the angle between the central axis of transmittance of said optically absorptive anisotropic layer and the normal direction of said optically absorptive anisotropic layer is 0 to 45°, and the maximum height difference of waviness in a 10 mm x 10 mm area on the film surface is 1.2 μm or less.

2. The film according to claim 1, comprising two of said optically absorptive anisotropic layers and at least one retardation layer between said two optically absorptive anisotropic layers.

3. The film according to claim 2, wherein the retardation layer comprises two layers, and the retardation layer is a λ / 2 plate.

4. The film of claim 1 further comprising a polarizer.

5. The film of any one of claims 1 to 4, further comprising an anti-reflective layer disposed on the outermost surface of the film.

6. The film according to any one of claims 1 to 4, having a surface reflectance of 1% or less.

7. The film according to any one of claims 1 to 4, further comprising one or more layers selected from the group consisting of a pressure-sensitive adhesive layer having a thickness of 10 μm or less and an adhesive layer having a thickness of 10 μm or less.

8. An optical member comprising the film according to any one of claims 1 to 4 and a transparent support.

9. The optical element according to claim 8, wherein the transparent support is glass.

10. An optical device comprising the optical member according to claim 8 and a light guide plate having a diffraction element disposed on a surface thereof, said optical member and said light guide plate being disposed at a distance from each other.

11. The optical device according to claim 10, wherein the transparent support in the optical member is disposed closer to the light guide plate than the film.

12. A head mounted display comprising the optical device according to claim 10 and an image display element.

13. A head mounted display comprising the optical device according to claim 11 and an image display element.

Images