Stacked optical films and image display devices

Abstract

The present invention addresses the problem of providing a laminated optical film which has a reflective circular polarizer and on which a reflected image is formed with high image sharpness, and an image display device using the laminated optical film. The problem is solved by sequentially providing at least the reflective circular polarizer, a phase difference layer for converting circularly polarized light into linearly polarized light, and a linear polarizer and by setting a surface roughness Ra at 100 nm or less on a surface of the reflective circular polarizer on the opposite side from the liner polarizer.

Description

[Technical Field]

[0001] The present invention relates to a laminated optical film having a reflective circular polarizer, a phase difference layer that converts circularly polarized light into linearly polarized light, and a linear polarizer in that order, and having a surface roughness Ra of 100 nm or less, and an image display device using this laminated optical film. [Background technology]

[0002] A reflective polarizer is a polarizer that reflects one polarization of incident light and transmits the other polarization. The reflected and transmitted light from a reflective polarizer are in mutually orthogonal polarization states. Mutually orthogonal polarization states are those located at opposite ends of the Poincaré sphere, such as mutually orthogonal linear polarization, and right-handed and left-handed circular polarization.

[0003] Examples of reflective linear polarizers that produce linearly polarized transmitted and reflected light include films made by stretching a dielectric multilayer film, as described in Patent Document 1, and wire grid polarizers, as described in Patent Document 2.

[0004] Furthermore, as a reflective circular polarizer in which transmitted and reflected light are circularly polarized, for example, a film having a layer on which a cholesteric liquid crystal phase is immobilized is known, as described in Patent Document 3.

[0005] Reflective polarizers are used to extract only specific polarizations from incident light or to separate incident light into two polarizations. For example, in liquid crystal display devices, it is used as a brightness-enhancing film that improves light utilization efficiency by reflecting and reusing unwanted polarization from the backlight. It is also used as a beam splitter in liquid crystal projectors that separates light from a light source into two linearly polarized beams and supplies each to the liquid crystal panel.

[0006] In recent years, a method using a reflective polarizer has been proposed for the purpose of reflecting part of external light and light from an image display device to generate virtual images and real images. For example, Patent Document 4 discloses an in-vehicle rearview mirror that uses a reflective polarizer to reflect light from behind. Patent Document 5 also discloses a method of generating a virtual image by reflecting and reciprocating light between a reflective polarizer and a half mirror in order to reduce the size and thickness of a display unit in a virtual reality display device and an electronic viewfinder. Further, Patent Document 6 discloses a method of generating a real image in the air using a reflective polarizer and a retroreflector.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0008] According to the studies of the present inventors, when a part of external light and light from an image display device are reflected by a reflective polarizer to generate virtual images and real images, it has been found that the sharpness of an image may decrease with the conventional reflective polarizers described in Patent Documents 1, 2, and 3.

[0009] The present invention has been made in view of the above problems, and the problem to be solved by the present invention is to provide a laminated optical film having a reflective circular polarizer and having high image sharpness of a reflected image, and an image display device using this laminated optical film.

Means for Solving the Problems

[0010] The inventors of the present invention have intensively studied the above problems and found that the above problems can be achieved by the following configurations.

[0011] [1] At least having a reflective circular polarizer, a retardation layer that converts circularly polarized light into linearly polarized light, and a linear polarizer in this order, A laminated optical film having a surface roughness Ra of 100 nm or less on the surface opposite to the linear polarizer with respect to the reflective circular polarizer. [2] The laminated optical film according to [1], further having a support with a surface roughness Ra of 50 nm or less. [3] The laminated optical film according to [2], wherein the support is a resin substrate having a peak temperature of tan δ of 170 °C or less. [4] The laminated optical film according to [1] without a support. [5] The laminated optical film according to any one of [1] to [4], wherein the reflective circular polarizer has at least a light reflection layer formed by fixing a cholesteric liquid crystal phase. [6] The laminated optical film according to any one of [1] to [5], wherein the reflective circular polarizer has at least a blue light reflection layer having a reflectance of 40% or more for light with a wavelength of 450 nm, a green light reflection layer having a reflectance of 40% or more for light with a wavelength of 530 nm, and a red light reflection layer having a reflectance of 40% or more for light with a wavelength of 630 nm. [7] The laminated optical film according to [6], wherein the reflective circular polarizer further has an infrared light reflection layer having a reflectance of 40% or more for light with a wavelength of 800 nm. [8] A laminated optical film according to any one of [1] to [7], wherein the reflective circular polarizer comprises at least a light-reflecting layer having a cholesteric liquid crystal phase containing a rod-shaped liquid crystal compound immobilized on it, and a light-reflecting layer having a cholesteric liquid crystal phase containing a disc-shaped liquid crystal compound immobilized on it. [9] A laminated optical film according to any one of [1] to [8], wherein the phase difference layer has substantially inverse dispersion with respect to wavelength.

[10] A laminated optical film according to any one of [1] to [9], wherein the phase difference layer is a layer on which a uniformly oriented liquid crystal compound is immobilized.

[11] A laminated optical film according to any one of [1] to

[10] , wherein the phase difference layer is a layer on which a liquid crystal compound is immobilized that is twisted and oriented with the thickness direction as the helical axis.

[12] A laminated optical film according to any one of [1] to

[11] , wherein the linear polarizer is made up of layers with a thickness of 10 μm or less.

[13] A laminated optical film according to any one of [1] to

[12] , wherein the linear polarizer has a light-absorbing anisotropic layer containing at least a liquid crystal compound and a dichroic substance.

[14] A laminated optical film according to any one of [1] to

[13] , further comprising a positive C plate.

[15] A laminated optical film according to any one of [1] to

[14] , further comprising an anti-reflective layer on any of its surfaces.

[16] The laminated optical film according to

[15] , wherein the anti-reflective layer is a moth-eye film or an AR film.

[17] An image display device having a laminated optical film as described in any of [1] to

[16] and an image display element.

[18] A virtual reality display device, the image display device described in

[17] . [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a laminated optical film with high image sharpness of reflected images, and an image display device using this laminated optical film. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 shows an example of a virtual reality display device using the laminated optical film of the present invention. [Figure 2] Figure 2 shows an example of a virtual reality display device using the laminated optical film of the present invention. [Figure 3] Figure 3 is a schematic diagram showing an example of the laminated optical film of the present invention. [Modes for carrying out the invention]

[0014] The present invention will be described in detail below with reference to the drawings. The following descriptions of constituent elements may be based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In this specification, numerical ranges represented by "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits.

[0015] In this specification, "orthogonal" does not mean that the angle between the two axes is exactly 90°, but rather that it means 90°±10°, preferably 90°±5°. Similarly, "parallel" does not mean that the angle between the two axes is exactly 0°, but rather that it means 0°±10°, preferably 0°±5°. Furthermore, "45°" does not mean that the angle between the two axes is exactly 45°, but rather that it means 45°±10°, preferably 45°±5°. However, in the context of polarization, "mutually orthogonal polarization states" refers to polarization states located at opposite antipodal points on the Poincaré sphere. As mentioned above, examples of mutually orthogonal linear polarization, as well as right-handed circular polarization and left-handed circular polarization, fall under this category.

[0016] In this specification, the "absorption axis" refers to the polarization direction in which the absorbance is maximized when linearly polarized light is incident on the surface. The "reflection axis" refers to the polarization direction in which the reflectance is maximized when linearly polarized light is incident on the surface. The "transmission axis" refers to the direction in which the absorption axis or reflection axis is perpendicular to the surface. Furthermore, the "latent axis" refers to the direction in which the refractive index is maximized.

[0017] In this specification, unless otherwise specified, phase difference refers to in-plane retardation and is denoted as Re(λ). Here, Re(λ) represents the in-plane retardation at wavelength λ, and unless otherwise specified, wavelength λ is assumed to be 550 nm. Furthermore, retardation in the thickness direction at wavelength λ is referred to as Rth(λ) in this specification. Re(λ) and Rth(λ) can be obtained using the values ​​measured at wavelength λ with an AxoScan OPMF-1 (OptoScience Co., Ltd.). By inputting the average refractive index ((nx+ny+nz) / 3) and film thickness (d(μm)) into AxoScan, Slow axis direction (°) Re(λ)=R0(λ) The formula Rth(λ) = ((nx+ny) / 2-nz)×d is calculated.

[0018] [Laminated Optical Film] The laminated optical film of the present invention comprises, in this order, at least a reflective circular polarizer, a phase difference layer that converts circularly polarized light into linearly polarized light, and a linear polarizer, wherein the surface roughness Ra of the surface opposite the linear polarizer to the reflective circular polarizer is 100 nm or less. Note that the surface roughness Ra is the arithmetic mean roughness Ra.

[0019] Figure 3 conceptually shows an example of the laminated optical film of the present invention. The laminated optical film 100 shown in Figure 3 has, from top to bottom in the figure, an anti-reflective layer 101, a positive C plate 102, a reflective circular polarizer 103, a positive C plate 104, a phase difference layer 105, and a linear polarizer 106. The phase difference layer 105 is a phase difference layer that converts circularly polarized light into linearly polarized light. As described above, the laminated optical film of the present invention has a surface roughness Ra of 100 nm or less on the surface opposite to the linear polarizer when viewed from the reflective circular polarizer. In other words, the laminated optical film of the present invention has a surface roughness Ra of 100 nm or less on the surface opposite to the linear polarizer when viewed from the reflective circular polarizer. Therefore, in the laminated optical film 100 shown in Figure 3, the surface roughness Ra of the surface of the anti-reflective layer 101, i.e., the top surface in the figure, is 100 nm or less.

[0020] The laminated optical film of the present invention has a reflective circular polarizer, a phase difference layer that converts circularly polarized light into linearly polarized light, and a linear polarizer in this order. By having such a configuration, the sharpness of the reflected light is high, and when used, for example, in an image display device, it is possible to display a sharp image. In other words, the image display device of the present invention, which uses the laminated optical film of the present invention, is an image display device capable of displaying images with high sharpness.

[0021] As will be shown later in the examples, the laminated optical film of the present invention is not limited to the configuration shown in Figure 3. In other words, as long as the laminated optical film of the present invention has a circular polarizer, a phase difference layer, and a linear polarizer in this order, various layer configurations are available, such as a configuration without an anti-reflective layer, and a configuration with only one positive C plate.

[0022] Furthermore, although the laminated optical film 100 shown in Figure 3 does not have a support, the present invention is not limited thereto. In other words, the laminated optical film of the present invention may have a support that does not exhibit optical properties for supporting the laminated optical film and / or each layer (film) constituting the laminated optical film. The support may be, for example, a support provided to form and support each layer constituting the laminated optical film, such as an anti-reflective layer 101 and a positive C plate 102, and remain as is in the laminated optical film of the present invention. Alternatively, the support may be provided separately from each layer to support the laminated optical film. Therefore, in the laminated optical film of the present invention, there are no restrictions on the number of supports or their positions, and various configurations are available. However, from the viewpoint of the surface roughness Ra mentioned above, a smaller number of supports is preferable. Therefore, a configuration without supports, as shown in the example in Figure 3, is preferably illustrated. These points will be described in detail later.

[0023] The laminated optical film of the present invention, for example, is combined with an image display element to constitute the image display device of the present invention. As described above, the laminated optical film of the present invention has a reflective circular polarizer, a phase difference layer, and a linear polarizer in this order. Furthermore, as will be described later, in an image display device, the laminated optical film of the present invention is arranged so that light transmitted through the reflective circular polarizer is incident on the phase difference layer. Moreover, as described above, the surface roughness Ra of the laminated optical film of the present invention on the side opposite to the linear polarizer relative to the reflective circular polarizer is 100 nm or less. Therefore, in the laminated optical film of the present invention, the surface with a surface roughness Ra of 100 nm is arranged to face the image display element. In other words, when the laminated optical film of the present invention is used in an image display device, the surface with a surface roughness Ra of 100 nm becomes the incident surface for the image displayed by the image display element.

[0024] As described above, the laminated optical film of the present invention can be used as a reflective-transmitting circular polarizer with high sharpness of transmitted light. As a suitable example of use, we will take a virtual reality (VR) display device as an image display device using the laminated optical film of the present invention and explain the operation of the laminated optical film of the present invention in detail.

[0025] Figure 1 shows a virtual reality display device using the laminated optical film 100 of the present invention. As described above, when used in an image display device, the laminated optical film 100 of the present invention is positioned so that the surface with a surface roughness Ra of 100 nm or less faces the display element. The virtual image display device shown in Figure 1 comprises an image display panel 500 which is an image display element, a circular polarizing plate 400, a half mirror 300, and the laminated optical film 100 of the present invention. In the virtual image display device, the light ray 1000 (display image) emitted by the image display panel 500 passes through the circular polarizer 400 and becomes circularly polarized, as shown in Figure 1, and then passes through the half mirror 300. The circular polarizer 400 converts the light ray 1000 into circularly polarized light in the direction of rotation that is reflected by the reflective circular polarizer 103 of the laminated optical film 100. The light ray 1000 then enters the laminated optical film 100 of the present invention from the side of the anti-reflective layer 101 and is totally reflected by the circular polarizer 103. The light ray 1000, totally reflected by the reflective circular polarizer 103, is reflected again by the half mirror 300 and incident on the laminated optical film 100 once more. At this time, the light ray 1000, having been reflected by the half mirror 300, has become circularly polarized, orthogonal to the circular polarization it had when it first incident on the laminated optical film 100. Therefore, the light ray 1000 passes through the laminated optical film 100 and is visible to the user. Specifically, the light ray 1000 passes through the reflective circular polarizer 103 and is converted to linearly polarized by the phase difference layer 105. The phase difference layer 105 converts the light ray 1000 (circularly polarized) that has passed through the reflective circular polarizer 103 into linearly polarized light in the direction that it passes through the linear polarizer 106. Therefore, the light ray 1000 converted to linearly polarized light by the phase difference layer 105 passes through the linear polarizer 106 and is visible to the user. As mentioned above, the laminated optical film 100 has a surface roughness Ra of 100 nm or less on the surface of the anti-reflective layer 101. Therefore, the image seen by the user is an image with little distortion and high sharpness. This point will be explained in more detail later. Furthermore, when light ray 1000 is reflected by half-mirror 300, the image is magnified because the half-mirror is concave, allowing the user to see a magnified virtual image. The mechanism described above is called a reciprocating optical system or a folded optical system.

[0026] On the other hand, Figure 2 is a schematic diagram illustrating the case where the light rays emitted by the image display panel 500, upon first incident on the stacked optical film, are not reflected and instead become stray light rays 2000. As can be seen from Figure 2, in this case, the user will see an image with a different optical path length and that is not magnified. This image is called ghosting or stray light, and its reduction is required. In a preferred embodiment, the laminated optical film 100 in the illustrated example has positive C plates 102 and 104 for adjusting Rth. Therefore, the laminated optical film 100 has a high degree of polarization of reflected light. As a result, the reflectivity when light rays first enter the laminated optical film 100 can be increased, and stray light and ghosting can be reduced. Furthermore, the laminated optical film 100 in the illustrated example, having the above configuration in a preferred embodiment, also has a high degree of polarization in transmitted light. Therefore, the transmittance when light rays are incident on the laminated optical film 100 for the second time can be increased, improving the brightness of the virtual image and further suppressing the color tint of the virtual image.

[0027] As shown in Figures 1 and 2, the laminated optical film 100 may be molded into a curved shape to match the lenses and other components that make up the image display device. A laminated optical film, conventionally known as a reflective circular polarizer, which consists of a reflective linear polarizer and a phase difference layer having a phase difference of 1 / 4 wavelength, has optical axes such as a transmission axis, a reflection axis, and a slow-phase axis. Therefore, when the film is molded into a curved shape or stretched, the optical axes become distorted, causing a decrease in the polarization degree of transmitted and reflected light. In contrast, the laminated optical film of the present invention, for example, is composed of a light-reflecting layer in which a cholesteric liquid crystal phase is fixed as a reflective circular polarizer, so that the reflective circular polarizer does not have an optical axis, and therefore a decrease in the degree of polarization due to stretching and molding is less likely to occur. Accordingly, even when the laminated optical film 100 is molded into a curved shape, a decrease in the degree of polarization is less likely to occur.

[0028] Furthermore, since the laminated optical film of the present invention has a reflective circular polarizer 103, a phase difference layer 105 that converts circularly polarized light to linearly polarized light, and a linear polarizer 106 in this order, leaked light from the reflective circular polarizer 103 can be converted to linearly polarized light and then absorbed by the linear polarizer 106. Specifically, as described above, the circular polarizer 400 converts the light ray 1000 into circularly polarized light in the direction of rotation that is reflected by the reflective circular polarizer 103 of the laminated optical film 100. In addition, the phase difference phase 105 converts the circularly polarized light that is orthogonal to the circularly polarized light selectively reflected by the reflective circular polarizer 103 into linearly polarized light in the direction that is transmitted by the linear polarizer 106. Therefore, when the circularly polarized light converted by the circular polarizer 400 passes through the reflective circular mesh 103 and becomes leak light (light ray 2000), this circularly polarized light is converted by the phase difference layer 105 into linearly polarized light in a direction perpendicular to the linearly polarized light passing through the linear polarizer 106. As a result, the leak light that passes through the reflective circular mesh 103 is absorbed by the linear polarizer 106. Therefore, the laminated optical film 100 of the present invention can prevent the transmission of unwanted light and increase the polarization degree of transmitted light. Furthermore, when the laminated optical film is stretched or molded, there are concerns that the slow axis of the phase difference layer 105 and the absorption axis of the linear polarizer 106 may be distorted. However, as described above, even if the reflective circular polarizer 103 is stretched or molded, the reflected and transmitted light retains a high degree of polarization, and the amount of light leakage from the reflective circular polarizer is small, so the increase in light leakage is kept to a minimum.

[0029] Furthermore, the laminated optical film of the present invention has a reflective circular polarizer, a phase difference layer that converts circularly polarized light into linearly polarized light, and a linear polarizer, in this order, and the surface roughness Ra of the surface opposite the linear polarizer to the reflective circular polarizer is 100 nm or less. In the case of the laminated optical film 100 shown in Figure 3, the surface roughness Ra of the anti-reflective layer 101 is 100 nm or less. As described above, when the laminated optical film of the present invention is used in an image display device, it is arranged such that the incident surface of the image displayed by the image display element is a surface with a surface roughness Ra of 100 nm or less. In the following description, the surface opposite to the linear polarizer with respect to the circular polarizer will also be conveniently referred to as the image incident surface. Furthermore, the phase difference layer that converts circularly polarized light to linearly polarized light will be simply referred to as the phase difference layer, and other phase difference layers will be noted, for example, as the phase difference layer that converts linearly polarized light to orthogonal linearly polarized light. The laminated optical film of the present invention can improve image sharpness when used in a virtual reality display device, for example, by setting the surface roughness Ra of the image incident surface to 100 nm or less.

[0030] The inventors of this invention hypothesize that when light is reflected by a laminated optical film containing a circular polarizer, if there are irregularities in each layer constituting the laminated optical film, the angle of the reflected light will be distorted, leading to image distortion and blurring, and a decrease in image sharpness. Therefore, in the laminated optical film of the present invention, it is preferable that all layers have a small surface roughness Ra. Each layer constituting the laminated optical film of the present invention preferably has a surface roughness Ra of 50 nm or less, more preferably 30 nm or less, and even more preferably 10 nm or less. Furthermore, from the viewpoint of improving the sharpness of the reflected image, it is particularly preferable that the Ra of the circular polarizer reflecting the image is small.

[0031] In this invention, the laminated optical film is made by laminating a number of layers. The inventors have found that when one layer is laminated on top of another layer with irregularities, the irregularities may be superimposed and amplified. Therefore, the surface irregularities of a laminated optical film are considered to be the result of the superposition of the irregularities of each layer constituting the laminated optical film. In other words, in a laminated optical film, the surface roughness Ra of the image incident surface is considered to represent the total degree of irregularities of all the layers constituting the laminated optical film. In other words, by making the surface roughness Ra of the image incident surface of the laminated optical film of the present invention 100 nm or less, the irregularities that lead to image distortion and blurring and cause a decrease in image sharpness can be sufficiently reduced in each layer constituting the laminated optical film. Therefore, when the laminated optical film of the present invention is used, for example, in an image display device such as the virtual reality display device described above, it is possible to display images with high sharpness.

[0032] In the laminated optical film of the present invention, the surface roughness Ra of the image incident surface is 100 nm or less. If the surface roughness Ra of the image incident surface exceeds 100 nm, when used in an image display device or the like, it is not possible to obtain an image with sufficiently high sharpness. In the laminated optical film of the present invention, the surface roughness Ra of the image incident surface is preferably 50 nm or less, more preferably 30 nm or less, and even more preferably 10 nm or less. The surface roughness Ra of the image incident surface is generally preferable as it is small, but is usually 5 nm or larger. By setting the surface roughness Ra of the image incident surface to 5 nm or larger, it is possible to better prevent the laminated optical films of the present invention from sticking together when they are stacked and stored or transported. Surface roughness Ra (arithmetic mean roughness Ra) can be measured, for example, using a non-contact surface and layer cross-sectional shape measurement system, VertScan (manufactured by Ryoka Systems Co., Ltd.).

[0033] The laminated optical film of the present invention preferably has a small number of point defects per unit area. In other words, since point defects lead to a decrease in the polarization degree of transmitted or reflected light, and a decrease in image sharpness, it is preferable to have a small number of point defects. The laminated optical film of the present invention is manufactured by laminating a large number of layers. Therefore, in order to reduce the number of point defects in the laminated optical film as a whole, it is preferable that the number of point defects in each layer is also small. Specifically, the number of point defects in each layer is preferably 20 or less per square meter, more preferably 10 or less, and even more preferably 1 or less. For the laminated optical film as a whole, the number of point defects is preferably 100 or less per square meter, more preferably 50 or less, and even more preferably 5 or less. Here, point defects include foreign matter, scratches, dirt, film thickness variations, and poor alignment of liquid crystal compounds. Furthermore, the number of point defects is preferably the number of point defects with a size of 100 μm or more, more preferably 30 μm or more, and even more preferably 10 μm or more.

[0034] Furthermore, the laminated optical film of the present invention may incorporate various sensors that use near-infrared light as a light source, such as eye tracking, facial expression recognition, and iris authentication, within the optical systems of virtual reality display devices and electronic viewfinders. Considering this point, it is preferable that the laminated optical film of the present invention be transparent to near-infrared light in order to minimize the impact on sensors.

[0035] The following describes each layer that constitutes the laminated optical film of the invention.

[0036] [Circular polarizer] The reflective circular polarizer used in the laminated optical film of the present invention is an optical component that separates incident light into right-handed circularly polarized light and left-handed circularly polarized light, specularly reflects one of the circularly polarized light and transmits the other. A reflective circular polarizer is preferable if it is a film that functions as a reflective circular polarizer on its own, from the viewpoint that a decrease in polarization degree and distortion of the polarization axis are suppressed when the laminated optical film is stretched or molded into a three-dimensional shape. A film that functions as a reflective circular polarizer on its own does not have a reflection axis or a transmission axis, so there is little concern about distortion of the polarization axis even when stretched or molded. In addition, a decrease in polarization degree due to distortion of the polarization axis is less likely to occur. As a film that functions as a reflective circular polarizer on its own, for example, an optical film having a light-reflecting layer with an immobilized cholesteric liquid crystal phase can be used, as described in Japanese Patent Application Publication No. 2020-060627. An optical film having a light-reflecting layer with an immobilized cholesteric liquid crystal phase is preferable because both the reflected light and the transmitted light have a high degree of polarization. In the following explanation, the "layer formed by fixing the cholesteric liquid crystal phase" will also be referred to as the "cholesteric liquid crystal layer" for convenience.

[0037] The circular polarizer used in the laminated optical film of the present invention preferably has at least a blue light reflective layer with a reflectivity of 40% or more for light at a wavelength of 450 nm, a green light reflective layer with a reflectivity of 40% or more for light at a wavelength of 530 nm, and a red light reflective layer with a reflectivity of 40% or more for light at a wavelength of 630 nm. This configuration is preferable because it can exhibit high reflectivity over a wide wavelength range in the visible region. The above reflectivity values ​​are those obtained when unpolarized light is incident on the circular polarizer at each respective wavelength. Some image display devices have emission peaks in the respective wavelength ranges of blue, green, and red light. For example, liquid crystal display devices with backlights containing quantum dots, liquid crystal display devices with backlights equipped with blue, green, and red LEDs, organic EL display devices, and micro-LED display devices have emission peaks with relatively narrow full width at half maximum in the respective wavelength ranges of blue, green, and red light. A narrow full width at half maximum for the emission peaks of each color is preferable because it improves color reproduction. When used in combination with these image display devices, it is preferable that the reflective circular polarizer has a reflection band selectively in the wavelength range corresponding to the emission peak of the image display device. Furthermore, the blue light reflective layer, green light reflective layer, and red light reflective layer, which are formed by immobilizing the cholesteric liquid crystal phase, may have a pitch gradient layer in which the helical pitch of the cholesteric liquid crystal phase is continuously varied in the thickness direction. For example, the green light reflective layer and the red light reflective layer can be manufactured continuously by referring to Japanese Patent Application Publication No. 2020-060627, etc.

[0038] Furthermore, when stretching or molding the laminated optical film of the present invention, the reflection wavelength range as a circular polarizer may shift to the short-wave side. Therefore, it is preferable that the reflection wavelength range is selected in advance, taking into account the expected wavelength shift. For example, when using an optical film having a layer (cholesteric liquid crystal layer) in which a cholesteric liquid crystal phase is immobilized as a reflective circular polarizer, the film may be stretched by stretching and molding, which may reduce the helical pitch of the cholesteric liquid crystal phase. Therefore, it is preferable to set the helical pitch of the cholesteric liquid crystal phase to be large in advance. Furthermore, considering the short-wave shift in the reflection wavelength range due to stretching and molding, it is also preferable for the reflective circular polarizer to have an infrared light reflective layer with a reflectivity of 40% or more at a wavelength of 800 nm. Furthermore, if the stretching ratio during stretching and molding is not uniform across the plane, an appropriate reflection wavelength range may be selected at each location within the plane according to the wavelength shift caused by stretching. In other words, there may be regions within the plane with different reflection wavelength ranges. It is also preferable to pre-define the reflection wavelength range to be wider than the required wavelength range, anticipating that the stretching ratio will differ at each location within the plane.

[0039] In the laminated optical film of the present invention, it is preferable that the reflective circular polarizer has a blue light reflective layer, a green light reflective layer, and a red light reflective layer laminated in this order. Furthermore, it is preferable that the blue light reflective layer is located on the opposite side from the phase difference layer that converts circularly polarized light into linearly polarized light. In this arrangement, light rays pass through the blue light reflective layer, the green light reflective layer, and the red light reflective layer in that order. The inventors estimate that, especially when light is incident at an oblique angle, the influence of the Rth of each layer becomes less significant, thus increasing the polarization degree of both the reflected and transmitted light.

[0040] Furthermore, it is preferable that the circular polarizer used in the laminated optical film of the present invention has a light-reflecting layer formed by immobilizing a cholesteric liquid crystal phase containing a rod-shaped liquid crystal compound, and a light-reflecting layer formed by immobilizing a cholesteric liquid crystal phase containing a disc-shaped liquid crystal compound. This configuration is preferable because, while the cholesteric liquid crystal phase containing the rod-shaped liquid crystal compound has a positive Rth, the cholesteric liquid crystal phase containing the disc-shaped liquid crystal compound has a negative Rth. As a result, their Rths cancel each other out, and the polarization degree of both reflected and transmitted light can be increased even with light incident from an oblique direction. According to the inventors' studies, in this case, the material preferably includes, in this order, a blue light reflective layer made of a cholesteric liquid crystal phase containing a disc-shaped liquid crystal compound, a red light reflective layer made of a cholesteric liquid crystal phase containing a rod-shaped liquid crystal compound, and a green light reflective layer made of a cholesteric liquid crystal phase containing a rod-shaped liquid crystal compound, with the blue light reflective layer being placed on the opposite side of the phase difference layer that converts circularly polarized light to linearly polarized light. Furthermore, if the reflective circular polarizer has light-reflecting layers made of rod-shaped and disc-shaped liquid crystal compounds, from the viewpoint of visual sensitivity, it is preferable that the order of the light-reflecting layers be green, red, and blue from the image display element side. Furthermore, if the reflective circular polarizer has a light-reflecting layer formed by immobilizing a cholesteric liquid crystal phase containing a rod-shaped liquid crystal compound, and a light-reflecting layer formed by immobilizing a cholesteric liquid crystal phase containing a disc-shaped liquid crystal compound, from the viewpoint of compensation, it is preferable that the types of liquid crystals be disc-shaped, rod-shaped, disc-shaped, or disc-shaped, rod-shaped, rod-shaped from the image display element side. However, the order of the light-reflecting layers and the type of liquid crystal are merely examples, and the reflective circular polarizer of the laminated optical film of the present invention is not limited to these configurations.

[0041] The thickness of the reflective circular polarizer is not particularly limited, but from the viewpoint of miniaturization, it is preferably 20 μm or less, and more preferably 10 μm or less.

[0042] In the laminated optical film of the present invention, the reflective circular polarizer may include a support, an alignment layer, and a light-reflecting layer. In this case, the support and the alignment layer may be a temporary support that is peeled off and removed when the laminated optical film is manufactured. Using a temporary support is preferable because, after transferring the reflective circular polarizer to another laminate, the temporary support can be peeled off and removed, thereby thinning the laminated optical film and eliminating the adverse effect of the phase difference of the temporary support on the polarization degree of transmitted and reflected light. The type of support is not particularly limited, but it is preferably transparent. For example, films made of cellulose acylate, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate, cyclic polyolefin, polyolefin, polyamide, polystyrene, and polyester can be used. Among these, cellulose acylate film, cyclic polyolefin, polyacrylate, and polymethacrylate are preferred. In addition, commercially available cellulose acetate films (for example, "TD80U" and "Z-TAC" manufactured by Fujifilm Corporation) can be used as the support. If the support is a temporary support, a support with high tear strength is preferred from the viewpoint of preventing breakage during delamination. For example, polycarbonate and polyester films are preferred. Furthermore, the support preferably has a small phase difference from the viewpoint of suppressing adverse effects on the polarization degree of transmitted and reflected light. Specifically, the size of the in-plane retardation Re is preferably 10 nm or less, and the absolute value of the size of the retardation Rth in the thickness direction is preferably 50 nm or less. Also, even if the support is used as a temporary support as described above, a small phase difference of the temporary support is preferable when performing quality inspection of the reflective circular polarizer and other laminates in the manufacturing process of the laminated optical film.

[0043] Furthermore, in order to minimize the impact on various sensors that use near-infrared light as a light source, such as eye tracking and facial recognition, as well as iris authentication, which are incorporated into the optical systems of virtual reality display devices and electronic viewfinders, it is preferable that the reflective circular polarizer used in the laminated optical film of the present invention is transparent to near-infrared light.

[0044] [Phase difference layer] The phase difference layer used in the laminated optical film of the present invention has the function of converting the emitted light into linearly polarized light when circularly polarized light is incident on it. For example, the phase difference layer can be one in which Re is approximately 1 / 4 wavelength at any wavelength in the visible range. In this case, the in-plane retardation Re(550) at a wavelength of 550 nm is preferably 120 to 150 nm, more preferably 125 to 145 nm, and even more preferably 135 to 140 nm. Furthermore, phase difference layers where the in-plane retardation Re is approximately 3 / 4 wavelength and approximately 5 / 4 wavelength are also preferable because they can convert linearly polarized light into circularly polarized light.

[0045] Furthermore, it is preferable that the phase difference layer used in the laminated optical film of the present invention has inverse dispersion with respect to wavelength. Inverse dispersion is preferable because it makes it possible to convert circularly polarized light into linearly polarized light over a wide wavelength range in the visible region. Here, having inverse dispersion with respect to wavelength means that the value of the phase difference at each wavelength increases as the wavelength increases. A phase difference layer having reverse dispersion can be produced, for example, by uniaxially stretching a polymer film such as a modified polycarbonate resin film having reverse dispersion, referring to Japanese Patent Application Publication No. 2017-049574. Furthermore, the phase difference layer having inverse dispersion only needs to have substantially inverse dispersion. For example, as disclosed in Japanese Patent Publication No. 06259925, it can be manufactured by laminating a phase difference layer with an in-plane retardation Re of approximately 1 / 4 wavelength and a phase difference layer with an in-plane retardation Re of approximately 1 / 2 wavelength, such that their slow axes form an angle of approximately 60°. In this case, even if the 1 / 4 wavelength phase difference layer and the 1 / 2 wavelength phase difference layer each have forward dispersion (the value of the phase difference at a given wavelength decreases as the wavelength increases), it is known that circularly polarized light can be converted to linearly polarized light over a wide wavelength range in the visible region, and can be considered to have substantially inverse dispersion. In this case, it is preferable that the laminated optical film of the present invention has a reflective circular polarizer, a 1 / 4 wavelength phase difference layer, a 1 / 2 wavelength phase difference layer, and a linear polarizer in this order.

[0046] Furthermore, it is preferable that the phase difference layer used in the laminated optical film of the present invention has a layer on which uniformly oriented liquid crystal compounds are immobilized. For example, a layer in which rod-shaped liquid crystal compounds are uniformly oriented horizontally with respect to the in-plane direction, and a layer in which disc-shaped liquid crystal compounds are uniformly oriented perpendicular to the in-plane direction can be used. Furthermore, referring to, for example, Japanese Patent Application Publication No. 2020-084070, a phase difference layer having reverse dispersion can also be fabricated by uniformly oriented and immobilizing rod-shaped liquid crystal compounds having reverse dispersion.

[0047] Furthermore, it is preferable that the phase difference layer used in the laminated optical film of the present invention has a layer in which liquid crystal compounds are immobilized in a torsion orientation with the thickness direction as the helical axis. For example, as disclosed in Japanese Patent Publication No. 05753922 and Japanese Patent Publication No. 05960743, a phase difference layer can be used which has a layer on which rod-shaped liquid crystal compounds or disc-shaped liquid crystal compounds are immobilized, with the thickness direction being twisted and oriented with the helical axis as the helical axis. In this case, the phase difference layer can be considered to have substantially inverse dispersion properties, which is preferable.

[0048] The thickness of the phase difference layer is not particularly limited, but from the viewpoint of thinning, it is preferably 0.1 to 8 μm, and more preferably 0.3 to 5 μm.

[0049] In the laminated optical film of the present invention, the phase difference layer may include a support, an alignment layer, and the phase difference layer. In this case, the support and the alignment layer may be temporary supports that are peeled off and removed when the laminated optical film is manufactured. When temporary supports are used, the laminated optical film can be made thinner by peeling off and removing the temporary supports after transferring the phase difference layer to another laminate, and furthermore, the adverse effect of the phase difference of the temporary supports on the polarization degree of transmitted and reflected light can be eliminated, which is preferable. The type of support is not particularly limited, but it is preferably transparent. For example, films made of cellulose acylate, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate, cyclic polyolefin, polyolefin, polyamide, polystyrene, and polyester can be used. Among these, cellulose acylate film, cyclic polyolefin, polyacrylate, and polymethacrylate are preferred. In addition, commercially available cellulose acetate films (for example, "TD80U" and "Z-TAC" manufactured by Fujifilm Corporation) can be used as the support. If the support is a temporary support, a support with high tear strength is preferred from the viewpoint of preventing breakage during delamination. For example, polycarbonate and polyester films are preferred. Furthermore, the support preferably has a small phase difference from the viewpoint of suppressing adverse effects on the polarization degree of transmitted and reflected light. Specifically, the size of the in-plane retardation Re is preferably 10 nm or less, and the absolute value of the size of the retardation Rth in the thickness direction is preferably 50 nm or less. Also, even if the support is used as a temporary support as described above, it is preferable that the phase difference of the temporary support be small when performing quality inspection of the phase difference layer and other laminates in the manufacturing process of the laminated optical film.

[0050] Furthermore, in order to minimize the impact on various sensors that use near-infrared light as a light source, such as eye tracking and facial recognition, as well as iris authentication, which are incorporated into the optical systems of virtual reality display devices and electronic viewfinders, it is preferable that the phase difference layer used in the laminated optical film of the present invention is transparent to near-infrared light.

[0051] [Linear polarizer] The linear polarizer used in the laminated optical film of the present invention is an absorption-type polarizer that absorbs linearly polarized light in the direction of the absorption axis and transmits linearly polarized light in the direction of the transmission axis. A general-purpose polarizer can be used as the linear polarizer. For example, a polarizer made by dyeing a dichroic substance onto polyvinyl alcohol or other polymer resins and then stretching and oriented it may be used, or a polarizer made by oriented a dichroic substance using the orientation of a liquid crystal compound may be used. From the viewpoint of availability and increasing the degree of polarization, a polarizer made by dyeing polyvinyl alcohol with iodine and then stretching it is preferred. The thickness of the linear polarizer is preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less. A thin linear polarizer prevents cracking and breakage of the film when the laminated optical film is stretched or molded. Furthermore, the single-plate transmittance of the linear polarizer is preferably 40% or higher, and more preferably 42% or higher. The degree of polarization of the linear polarizer is preferably 90% or higher, more preferably 95% or higher, and even more preferably 99% or higher. In this invention, the single-plate transmittance and degree of polarization of the linear polarizer are measured using an automatic polarizing film measuring device: VAP-7070 (manufactured by JASCO Corporation). Furthermore, it is preferable that the direction of the transmission axis of the linear polarizer coincides with the direction of the polarization axis of the light converted to linear polarization by the phase difference layer. For example, if the phase difference layer is a layer having a phase difference of 1 / 4 wavelength, it is preferable that the angle between the transmission axis of the linear polarizer and the lagging axis of the phase difference layer is approximately 45°.

[0052] The linear polarizer used in the laminated optical film of the present invention is preferably a light-absorbing anisotropic layer containing a liquid crystal compound and a dichroic substance. A linear polarizer containing a liquid crystal compound and a dichroic substance is preferable because it can be made thin and is less prone to cracking and fracturing even when stretched and molded. The thickness of the light-absorbing anisotropic layer is not particularly limited, but from the viewpoint of thinning, it is preferably 0.1 to 8 μm, and more preferably 0.3 to 5 μm. A linear polarizer containing a liquid crystal compound and a dichroic substance can be manufactured, for example, by referring to Japanese Patent Publication No. 2020-023153. From the viewpoint of improving the polarization degree of the linear polarizer, the light-absorbing anisotropic layer preferably has an orientation degree of 0.95 or higher for the dichroic substance, and more preferably 0.97 or higher.

[0053] When the linear polarizer used in the laminated optical film of the present invention consists of a light-absorbing anisotropic layer containing a liquid crystal compound and a dichroic substance, the linear polarizer may include a support, an alignment layer, and a light-absorbing anisotropic layer. In this case, the support and alignment layer may be a temporary support that is peeled off and removed when the laminated optical film is manufactured. Using a temporary support is preferable because it allows for the thinning of the laminated optical film by transferring the light-absorbing anisotropic layer to another laminate and then peeling off and removing the temporary support, and also eliminates the adverse effect of the phase difference of the temporary support on the polarization degree of transmitted and reflected light. The type of support is not particularly limited, but it is preferably transparent. For example, films made of cellulose acylate, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate, cyclic polyolefin, polyolefin, polyamide, polystyrene, and polyester can be used. Among these, cellulose acylate film, cyclic polyolefin, polyacrylate, and polymethacrylate island are preferred. In addition, commercially available cellulose acetate film (for example, "TD80U" and "Z-TAC" manufactured by Fujifilm Corporation) can be used as the support. If the support is a temporary support, a support with high tear strength is preferred from the viewpoint of preventing breakage during delamination. For example, polycarbonate and polyester films are preferred. Furthermore, the support preferably has a small phase difference from the viewpoint of suppressing adverse effects on the polarization degree of transmitted and reflected light. Specifically, the size of the in-plane retardation Re is preferably 10 nm or less, and the absolute value of the size of the retardation Rth in the thickness direction is preferably 50 nm or less. Also, even if the support is used as a temporary support as described above, a small phase difference of the temporary support is preferable when performing quality inspection of the light-absorbing anisotropic layer and other laminates in the manufacturing process of the laminated optical film.

[0054] Furthermore, in order to minimize the impact on various sensors that use near-infrared light as a light source, such as eye tracking and facial recognition, as well as iris authentication, which are incorporated into the optical systems of virtual reality display devices and electronic viewfinders, it is preferable that the linear polarizer used in the laminated optical film of the present invention is transparent to near-infrared light.

[0055] [Light-absorbing anisotropic layer] Here, we will explain the light-absorbing anisotropic layer in more detail. The light-absorbing anisotropic layer contains a liquid crystal compound and a dichroic substance, and by uniformly oriented the liquid crystal compound, the dichroic substance can also be oriented in one direction. It is preferable that the liquid crystal compound and dichroic substance have radical polymerizable groups, as this suppresses the decrease in polarization degree during stretching and molding. When the liquid crystal compound and dichroic substance have radical polymerizable groups, it is preferable that the molar content of the radical polymerizable groups relative to the solid weight of the composition used to form the light-absorbing anisotropic layer is 0.6 mmol / g or more, more preferably 1.0 mmol / g or more, and even more preferably 1.5 mmol / g or more.

[0056] <Liquid crystal compounds> The liquid crystal compound contained in the composition for forming the light-absorbing anisotropic layer is preferably a liquid crystal compound that does not exhibit dichroism in the visible range. Both low-molecular-weight liquid crystal compounds and high-molecular-weight liquid crystal compounds can be used as liquid crystal compounds. Here, "low-molecular-weight liquid crystal compounds" refer to liquid crystal compounds that do not have repeating units in their chemical structure. "High-molecular-weight liquid crystal compounds" refer to liquid crystal compounds that have repeating units in their chemical structure. Examples of low-molecular-weight liquid crystal compounds include those described in paragraphs

[0027] to

[0034] of Japanese Patent Publication No. 2013-228706. Among these, low-molecular-weight liquid crystal compounds exhibiting smeck-tic properties are preferred. Examples of polymeric liquid crystal compounds include the thermotropic liquid crystal polymer described in Japanese Patent Publication No. 2011-237513. Furthermore, it is preferable that the polymeric liquid crystal compound has crosslinkable groups (e.g., acryloyl groups and methacryloyl groups, etc.) at its terminals. Liquid crystal compounds may be used individually or in combination of two or more. It is also preferable to use a high-molecular-weight liquid crystal compound and a low-molecular-weight liquid crystal compound in combination. The liquid crystal compound content is preferably 25 to 2000 parts by mass, more preferably 33 to 1000 parts by mass, and even more preferably 50 to 500 parts by mass, based on the dichroic substance content in the composition. Having the liquid crystal compound content within the above range further improves the polarizer orientation.

[0057] The liquid crystal compound is preferably a polymer liquid crystal compound because it results in a higher degree of orientation of the resulting light-absorbing anisotropic layer, and more preferably a polymer liquid crystal compound containing a repeating unit represented by the following formula (1) (hereinafter also abbreviated as "repeating unit (1)").

[0058] [ka]

[0059] In formula (1) above, P1 represents a repeating main chain, 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.

[0060] Specifically, the main chain of the repeating unit represented by P1 can be, for example, a group represented by the following formulas (P1-A) to (P1-D), and among these, the group represented by the following formula (P1-A) is preferred from the viewpoint of the diversity of monomers used as raw materials and ease of handling.

[0061] [ka]

[0062] In equations (P1-A) to (P1-D), "*" represents the bond position with L1 in equation (1). In equation (P1-A), R 1 R represents a hydrogen atom or a methyl group. In formula (P1-D), R 2 represents an alkyl group. The group represented by formula (P1-A) is preferably a unit of the substructure of the poly(meth)acrylic acid ester obtained by polymerization of (meth)acrylic acid ester, because it results in a higher degree of orientation of the resulting light-absorbing anisotropic layer. The group represented by formula (P1-B) is preferably an ethylene glycol unit in polyethylene glycol obtained by polymerizing ethylene glycol, because it results in a higher degree of orientation of the resulting light-absorbing anisotropic layer. The group represented by formula (P1-C) is preferably a propylene glycol unit obtained by polymerizing propylene glycol, because it results in a higher degree of orientation of the resulting light-absorbing anisotropic layer. The group represented by formula (P1-D) is preferably a siloxane unit of a polysiloxane obtained by condensation polymerization of silanol, because it results in a higher degree of orientation of the resulting light-absorbing anisotropic layer.

[0063] L1 is a single bond or a divalent linking group. The divalent linking groups represented by L1 include -C(O)O-, -OC(O)-, -O-, -S-, and -C(O)NR 3 -, -NR 3 C(O)-, -SO2-, and -NR 3 R 4 - are some examples. In the formula, R3 and R 4 each independently represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms. When P1 is a group represented by the formula (P1-A), L1 is preferably a group represented by -C(O)O- because the degree of orientation of the resulting light absorption anisotropic layer becomes higher. When P1 is a group represented by the formulas (P1-B) to (P1-D), L1 is preferably a single bond because the degree of orientation of the resulting light absorption anisotropic layer becomes higher.

[0064] 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 fluoroalkylene structure because it is likely to exhibit liquid crystallinity and for reasons such as the availability of raw materials. Here, the oxyethylene structure represented by SP1 is preferably a group represented by *-(CH2-CH2O) n1 -*. In the formula, n1 represents an integer of 1 to 20, and * represents the bonding position with L1 or M1 in the above formula (1). n1 is preferably an integer of 2 to 10, more preferably an integer of 2 to 4, and most preferably 3 because the degree of orientation of the resulting light absorption anisotropic layer becomes higher. Also, the oxypropylene structure represented by SP1 is preferably a group represented by *-(CH(CH3)-CH2O) n2 -*. In the formula, n2 represents an integer of 1 to 3, and * represents the bonding position with L1 or M1. Also, the polysiloxane structure represented by SP1 is preferably a group represented by *-(Si(CH3)2-O) n3 -*. In the formula, n3 represents an integer of 6 to 10, and * represents the bonding position with L1 or M1. Also, the fluoroalkylene structure represented by SP1 is preferably a group represented by *-(CF2-CF2) n4A base represented by -* is preferred. In the formula, n4 represents an integer between 6 and 10, and * represents the bonding position with L1 or M1.

[0065] The mesogenic group represented by M1 is the group that represents the main skeleton of liquid crystal molecules that contribute to liquid crystal formation. Liquid crystal molecules exhibit liquid crystalline properties, which is an intermediate state (mesophase) between the crystalline state and the isotropic liquid state. There are no particular restrictions on the mesogenic group; for example, refer to the description in "Flussige Kristalle in Tabellen II" (VEB Deutsche Verlag fur Grundstoff Industrie, Leipzig, 1984), especially pages 7 to 16, and the description in the Liquid Crystal Handbook (Maruzen, 2000), edited by the Liquid Crystal Handbook Editorial Committee, especially Chapter 3. The mesogenic group is preferably a group having at least one cyclic structure selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups, and alicyclic groups. The mesogenic group preferably has aromatic hydrocarbon groups, more preferably has 2 to 4 aromatic hydrocarbon groups, and even more preferably has 3 aromatic hydrocarbon groups, because this results in a higher degree of orientation of the resulting light-absorbing anisotropic layer.

[0066] As for the mesogenic group, a group represented by the following formula (M1-A) or the following formula (M1-B) is preferred, and the group represented by formula (M1-B) is more preferred, from the viewpoint of exhibiting liquid crystalline properties, adjusting the liquid crystal phase transition temperature, availability of raw materials, and suitability for synthesis, as well as because it exhibits superior effects of the present invention.

[0067] [ka]

[0068] In formula (M1-A), A1 is a divalent group selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups, and alicyclic groups. These groups may be substituted with alkyl groups, alkyl fluoride groups, alkoxy groups, or substituents. The divalent group represented by A1 is preferably a 4- to 6-membered ring. Furthermore, the divalent group represented by A1 may be a monoring or a fused ring. * indicates the binding site with SP1 or T1.

[0069] Examples of the divalent aromatic hydrocarbon group represented by A1 include phenylene, naphthylene, fluorene-diyl, anthracene-diyl, and tetracene-diyl groups. From the viewpoint of the diversity of mesogenic skeleton design and the availability of raw materials, a phenylene or naphthylene group is preferred, with a phenylene group being more preferred.

[0070] The divalent heterocyclic group represented by A1 may be either aromatic or non-aromatic, but from the viewpoint of improving the degree of orientation, it is preferable that it be a divalent aromatic heterocyclic group. Atoms other than carbon that constitute a divalent aromatic heterocyclic group include nitrogen, sulfur, and oxygen atoms. If an aromatic heterocyclic group has multiple atoms other than carbon that constitute the ring, these may be the same or different. Specific examples of divalent aromatic heterocyclic groups include, for example, pyridylene (pyridine-diyl group), pyridazine-diyl group, imidazole-diyl group, thienylene (thiophene-diyl group), quinolylene (quinoline-diyl group), isoquinolylene (isoquinoline-diyl group), oxazole-diyl group, thiazole-diyl group, oxadiazole-diyl group, benzothiazole-diyl group, benzothiadiazole-diyl group, phthalimide-diyl group, thienothiazole-diyl group, thiazolothiazole-diyl group, thienothiophene-diyl group, and thienoxazole-diyl group.

[0071] Specific examples of the divalent alicyclic group represented by A1 include the cyclopentylene group and the cyclohexylene group.

[0072] In equation (M1-A), a1 represents an integer between 1 and 10. If a1 is 2 or greater, multiple A1s may be the same or different.

[0073] In formula (M1-B), A2 and A3 are each independently divalent groups selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups, and alicyclic groups. Specific examples and preferred embodiments of A2 and A3 are the same as those for A1 in formula (M1-A), so their explanation is omitted. In formula (M1-B), a2 represents an integer from 1 to 10. When a2 is 2 or greater, multiple A2s may be the same or different, multiple A3s may be the same or different, and multiple LA1s may be the same or different. For the reason that the degree of orientation of the resulting light-absorbing anisotropic layer is higher, a2 is preferably an integer of 2 or greater, and more preferably 2. In formula (M1-B), when a2 is 1, LA1 is a divalent linking group. When a2 is 2 or more, each of the multiple LA1s is independently either a single bond or a divalent linking group, and at least one of the multiple LA1s is a divalent linking group. When a2 is 2, it is preferable that one of the two LA1s is a divalent linking group and the other is a single bond, because this results in a higher degree of orientation of the resulting light-absorbing anisotropic layer.

[0074] In formula (M1-B), the divalent linking group represented by LA1 is -O-, -(CH2) g -,-(CF2) g -, -Si(CH3)2-, -(Si(CH3)2O) g -,-(OSi(CH3)2) g-(g represents an integer from 1 to 10.), -N(Z)-, -C(Z)=C(Z')-, -C(Z)=N-, -N=C(Z)-, -C(Z)2- C(Z')2-, -C(O)-, -OC(O)-, -C(O)O-, -OC(O)O-, -N(Z)C(O)-, -C(O)N(Z)-, - C(Z)=C(Z')-C(O)O-, -OC(O)-C(Z)=C(Z')-, -C(Z)=N-, -N=C(Z)-, -C(Z)=C( Z')-C(O)N(Z”)-, -N(Z”)-C(O)-C(Z)=C(Z')-, -C(Z)=C(Z')-C(O)-S-, -SC( Examples include -C(O)-C(Z)=C(Z')-, -C(Z)=NN=C(Z')- (where Z, Z', and Z'' independently represent hydrogen, a C1-C4 alkyl group, a cycloalkyl group, an aryl group, a cyano group, or a halogen atom), -C≡C-, -N=N-, -S-, -S(O)-, -S(O)(O)-, -(O)S(O)O-, -O(O)S(O)O-, -SC(O)-, and -C(O)S-. Among these, -C(O)O- is preferred because it results in a higher degree of orientation of the resulting light-absorbing anisotropic layer. LA1 may also be a group formed by combining two or more of these groups.

[0075] An example of M1 is the following structure. In the example below, "Ac" represents an acetyl group.

[0076] [ka]

[0077] [ka]

[0078] Examples of terminal groups represented by T1 include hydrogen atoms, halogen atoms, cyano groups, nitro groups, hydroxyl groups, C1-C10 alkyl groups, C1-C10 alkoxy groups, C1-C10 alkylthio groups, C1-C10 alkoxycarbonyloxy groups, C1-C10 alkoxycarbonyl groups (ROC(O)-: R is an alkyl group), C1-C10 acyloxy groups, C1-C10 acylamino groups, C1-C10 alkoxycarbonylamino groups, C1-C10 sulfonylamino groups, C1-C10 sulfamoyl groups, C1-C10 carbamoyl groups, C1-C10 sulfinyl groups, and C1-C10 ureido groups and (meth)acryloyloxy group-containing groups. Examples of the (meth)acryloyloxy group-containing groups mentioned above include the group represented by -LA (where L represents a single bond or a linking group; specific examples of linking groups are the same as those for L1 and SP1 above; and A represents a (meth)acryloyloxy group). 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, because it results in a higher degree of orientation of the resulting light-absorbing anisotropic layer. These terminal groups may be further substituted with these groups or with polymerizable groups described in Japanese Patent Application Publication No. 2010-244038. The number of atoms in the main chain of T1 is preferably 1 to 20, more preferably 1 to 15, even more preferably 1 to 10, and particularly preferably 1 to 7, because this results in a higher degree of orientation of the resulting light-absorbing anisotropic layer. The degree of polarizer orientation is further improved when the number of atoms in the main chain of T1 is 20 or less. Here, "main chain" in T1 refers to the longest molecular chain bonded to M1, and hydrogen atoms are not counted in the number of atoms in the main chain of T1. For example, if T1 is an n-butyl group, the number of atoms in the main chain is 4, and if T1 is a sec-butyl group, the number of atoms in the main chain is 3.

[0079] The content of repeating units (1) is preferably 20 to 100% by mass relative to 100% by mass of the total repeating units of the polymer liquid crystal compound, because this results in a higher degree of orientation of the resulting light-absorbing anisotropic layer. In this invention, the content of each repeating unit in the polymer liquid crystal compound is calculated based on the amount (mass) of each monomer used to obtain each repeating unit. The repeating unit (1) may be present as a single unit or as two or more units in the polymer liquid crystal compound. In particular, it is preferable to have two types of repeating units (1) in the polymer liquid crystal compound because this results in a higher degree of orientation of the resulting light-absorbing anisotropic layer.

[0080] When a polymeric liquid crystal compound contains two types of repeating units (1), it is preferable that the terminal group represented by T1 in one of the repeating units (repeating unit A) is an alkoxy group, and the terminal group represented by T1 in the other repeating unit (repeating unit B) is a group other than an alkoxy group, in order to achieve a higher degree of orientation in the resulting light-absorbing anisotropic layer. In the repeating unit B described above, the terminal group represented by T1 is preferably an alkoxycarbonyl group, a cyano group, or a (meth)acryloyloxy group-containing group, and more preferably an alkoxycarbonyl group or a cyano group, because this results in a higher degree of orientation of the resulting light-absorbing anisotropic layer. The ratio (A / B) of the content of repeating unit A in the polymer liquid crystal compound to the content of repeating unit B in the polymer liquid crystal compound is preferably 50 / 50 to 95 / 5, more preferably 60 / 40 to 93 / 7, and even more preferably 70 / 30 to 90 / 10, in order to achieve a higher degree of orientation in the resulting light-absorbing anisotropic layer.

[0081] <Repeating Unit (3-2)> The polymer liquid crystal compound of the present invention may further contain repeating units represented by the following formula (3-2) (hereinafter also referred to as "repeating unit (3-2)"). This offers advantages such as improved solubility of the polymer liquid crystal compound in solvents and easier adjustment of the liquid crystal phase transition temperature. The repeating unit (3-2) differs from the repeating unit (1) in that it does not have at least a mesogenic group. If the polymeric liquid crystal compound contains repeating units (3-2), the polymeric liquid crystal compound is a copolymer of repeating units (1) and repeating units (3-2) (and may also be a copolymer containing repeating units A and B), and may be any polymer such as a block polymer, an alternating polymer, a random polymer, or a graft polymer.

[0082] [ka]

[0083] In formula (3-2), P3 represents the repeating main chain, L3 represents a single bond or a divalent linking group, SP3 represents a spacer group, and T3 represents a terminal group. The specific examples of P3, L3, SP3, and T3 in equation (3-2) are the same as those of P1, L1, SP1, and T1 in equation (1) above. Here, in formula (3-2), T3 preferably has a polymerizable group from the viewpoint of improving the intensity of the light-absorbing anisotropic layer.

[0084] When repeating units (3-2) are present, the content is preferably 0.5 to 40% by mass, and more preferably 1 to 30% by mass, relative to 100% by mass of the total repeating units of the polymeric liquid crystal compound. The repeating unit (3-2) may be present as a single unit or as two or more units in the polymer liquid crystal compound. When two or more repeating units (3-2) are present, it is preferable that their total amount is within the above range.

[0085] (Weight average molecular weight) The weight-average molecular weight (Mw) of the polymeric liquid crystal compound is preferably between 1,000 and 500,000, and more preferably between 2,000 and 300,000, because this results in a higher degree of orientation of the resulting light-absorbing anisotropic layer. If the Mw of the polymeric liquid crystal compound falls within this range, handling of the polymeric liquid crystal compound becomes easier. In particular, from the viewpoint of suppressing cracks during coating, the weight-average molecular weight (Mw) of the polymer liquid crystal compound is preferably 10,000 or more, and more preferably between 10,000 and 300,000. Furthermore, from the viewpoint of the temperature latitude of the degree of orientation, the weight-average molecular weight (Mw) of the polymer liquid crystal compound is preferably less than 10,000, and preferably between 2,000 and 10,000. Here, the weight-average molecular weight and number-average molecular weight in this invention are values ​​measured by gel permeation chromatography (GPC). • Solvent (eluent): N-methylpyrrolidone ·Device name: TOSOH HLC-8220GPC • Column: Three TOSOH TSKgelSuperAWM-H (6mm x 15cm) columns connected together are used. • Column temperature: 25℃ • Sample concentration: 0.1% by mass ·Flow rate: 0.35mL / min • Calibration curve: A calibration curve was used based on 7 samples of TOSOH TSK standard polystyrene with Mw=2,800,000 to 1,050 (Mw / Mn=1.03 to 1.06).

[0086] (Content) In the present invention, the content of the liquid crystal compound is preferably 50 to 99% by mass of the solid content in the composition for forming the light absorption anisotropy layer, and more preferably 70 to 96% by mass. Here, "solid content in a composition for forming a light-absorbing anisotropic layer" refers to the components excluding the solvent. Specific examples of solid content include the liquid crystal compounds mentioned above, as well as dichroic substances, polymerization initiators, and interface modifiers described later.

[0087] <Dichroic substances> The composition for forming a light-absorbing anisotropic layer contains a dichroic substance. Dichroic materials are not particularly limited and include visible light absorbing materials (dichroic dyes), ultraviolet absorbing materials, infrared light absorbing materials, nonlinear optical materials, carbon nanotubes, etc. Conventionally known dichroic materials (dichroic dyes) can be used. Specifically, for example, paragraphs

[0067] to

[0071] of JP 2013-228706, paragraphs

[0008] to

[0026] of JP 2013-227532, paragraphs

[0008] to

[0015] of JP 2013-209367, paragraphs

[0045] to

[0058] of JP 2013-14883, paragraphs

[0012] to

[0029] of JP 2013-109090, and paragraph

[0009] of JP 2013-101328. Paragraphs 】~

[0017] , paragraphs

[0051] ~

[0065] of JP 2013-37353, paragraphs

[0049] ~

[0073] of JP 2012-63387, paragraphs

[0016] ~

[0018] of JP 11-305036, paragraphs

[0009] ~

[0011] of JP 2001-133630, paragraphs

[0030] ~

[0169] of JP 2011-215337, paragraphs

[0021] ~【0 Paragraph 075, paragraphs

[0011] to

[0025] of JP 2010-215846, paragraphs

[0017] to

[0069] of JP 2011-048311, paragraphs

[0013] to

[0133] of JP 2011-213610, paragraphs

[0074] to

[0246] of JP 2011-237513, paragraphs

[0005] to

[0051] of JP 2016-006502, paragraphs

[0005] to [ Examples include paragraph

[0041] , paragraphs

[0008] to

[0062] of Publication No. WO2016 / 136561, paragraphs

[0014] to

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

[0014] to

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

[0013] to

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

[0014] to

[0034] of International Publication No. 2018 / 164252.

[0088] In the present invention, two or more dichroic materials may be used in combination. For example, from the viewpoint of obtaining a high degree of polarization over a wider wavelength range, it is preferable to use at least one dichroic material having a maximum absorption wavelength in the range of 370 to 550 nm and at least one dichroic material having a maximum absorption wavelength in the range of 500 to 700 nm in combination.

[0089] The above-mentioned dichroic substance may have crosslinking groups. In particular, having crosslinking groups is preferable from the viewpoint of suppressing changes in the degree of polarization during heating. Examples of the above crosslinkable groups include (meth)acryloyl groups, epoxy groups, oxetanyl groups, and styryl groups, with (meth)acryloyl groups being preferred.

[0090] (Content) The content of the dichroic substance in the composition for forming the light-absorbing anisotropic layer is preferably 1 to 400 parts by mass, more preferably 2 to 100 parts by mass, and even more preferably 5 to 30 parts by mass, per 100 parts by mass of the liquid crystal compound, because this results in a higher degree of orientation of the dichroic substance.

[0091] Preferably, the liquid crystal compounds and dichroic materials described above do not absorb near-infrared light. This minimizes the influence of the light-absorbing anisotropy layer on various sensors that use near-infrared light as a light source, such as eye tracking, facial expression recognition, and iris authentication, which are incorporated into optical systems such as virtual reality display devices and electronic viewfinders.

[0092] <Surfactants> The surfactant contained in the composition for forming the light-absorbing anisotropic layer can be a conventionally known surfactant, but a copolymer having repeating units containing alkyl fluoride and repeating units containing a ring structure is preferred. In the following explanation, repeating units containing alkyl fluoride are also referred to as 'repeating unit F', and repeating units containing a ring structure are also referred to as 'repeating unit M'.

[0093] The Hansen solubility parameter was calculated using HSPiP (Ver. 5.1.08) by inputting the compound's structural formula. The dispersion term δD is a term resulting from van der Waals forces. In the case of copolymers, δD and volume were calculated using structural formulas in which the bonds of each repeating unit were replaced with hydrogen atoms, and the average value based on the volume ratio was adopted. High-temperature aging at 80°C to 140°C is required to orient the liquid crystal compound, and during high-temperature aging, the viscosity of the composition decreases, which can lead to repellency failures. The inventors' investigation revealed a correlation between the surfactant's δD and the failure of the repellent. Specifically, a surfactant with a δD of 15.5 to 17.5 is preferred, and one with a δD of 15.8 to 17.0 is more preferred.

[0094] (Repeating unit F) The repeating unit F of the above copolymer is preferably a repeating unit represented by the following formula (a).

[0095] [ka]

[0096] In the above formula (a), R a1 R represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. a2 This represents an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, in which at least one carbon atom has a fluorine atom as a substituent.

[0097] In the above formula (a), R a2 For the reason that orientation defects in the resulting light-absorbing anisotropic layer are more suppressed, a C1-C10 alkyl group or a C2-C10 alkenylene group is preferred, and a C1-C10 alkyl group is more preferred, R a2 It is particularly preferable that more than half of the carbon atoms contained in the material have fluorine atoms as substituents.

[0098] In the present invention, the repeating unit F of the copolymer is more preferably a repeating unit represented by the following formula (b).

[0099] [ka]

[0100] In the above formula (b), R a1 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, ma and na each independently represent a non-negative integer, and X represents a hydrogen atom or a fluorine atom. Here, ma is preferably an integer between 1 and 10, and na is preferably between 4 and 12.

[0101] Specifically, examples of monomers that form the repeating unit F of the above copolymer (hereinafter also referred to as "fluoroalkyl group-containing monomers") include 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3,3-pentafluoropropyl (meth)acrylate, 2-(perfluorobutyl)ethyl (meth)acrylate, 2-(perfluorohexyl)ethyl (meth)acrylate, 2-(perfluorooctyl)ethyl (meth)acrylate, 2-(perfluorodecyl)ethyl (meth)acrylate, 2-(perfluoro-3-methylbutyl)ethyl (meth)acrylate, 2-(perfluoro-5-methylhexyl)ethyl (meth)acrylate, 2-(perfluoro-7-methyloctyl)ethyl (meth)acrylate, 1H,1H,3H-tetrafluoropropyl (meth)acrylate, and 1H,1H,5H-octafluoropene Examples include methyl (meth)acrylate, 1H,1H,7H-dodecafluoroheptyl (meth)acrylate, 1H,1H,9H-hexadecafluorononyl (meth)acrylate, 1H-1-(trifluoromethyl)trifluoroethyl (meth)acrylate, 1H,1H,3H-hexafluorobutyl (meth)acrylate, 3-perfluorobutyl-2-hydroxypropyl (meth)acrylate, 3-perfluorohexyl-2-hydroxypropyl (meth)acrylate, 3-perfluorooctyl-2-hydroxypropyl (meth)acrylate, 3-(perfluoro-3-methylbutyl)-2-hydroxypropyl (meth)acrylate, 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl (meth)acrylate, and 3-(perfluoro-7-methyloctyl)-2-hydroxypropyl (meth)acrylate.

[0102] In the present invention, the proportion of copolymerized fluoroalkyl group-containing monomers is preferably 0.01 to 100 moles, more preferably 0.1 to 50 moles, and even more preferably 1 to 30 moles, per mole of the mesogenic group-containing monomer described later, from the viewpoint of reactivity and surface modification effect.

[0103] (Repeat unit M) The repeating unit M of the copolymer described above may be any unit that includes a ring structure. A ring structure refers to at least one ring structure selected from the group consisting of, for example, aromatic hydrocarbon groups, heterocyclic groups, and alicyclic groups. From the viewpoint of suppressing orientation defects, it is preferable to have two or more ring structures.

[0104] In the present invention, the repeating unit F of the copolymer is more preferably a repeating unit represented by the following formula (b).

[0105] [ka]

[0106] In the above formula (c), R a1 L1 represents a hydrogen atom or an alkyl group with 1 to 20 carbon atoms, L4 and L5 represent a single bond or an alkylene group with 1 to 8 carbon atoms, G1 and G2 represent a divalent cyclic group, and T1 represents a terminal group. n represents an integer from 0 to 4.

[0107] For the alkylene groups represented by L4 and L5, one or more -CH2- groups constituting the alkylene group are single bonds, -O-, -S-, and -NR. 31 -, -C(=O)-, -C(=S)-, -CR 32 =CR 32 -, -C≡C-, -SiR 33 R 34 -, -N=N-, -CR 35 =NN=CR 36 -, -CR 37R may be replaced by at least one group selected from the group consisting of =N- and -SO2-, 31 ~R 37 Each of these independently represents a hydrogen atom, a halogen atom, a cyano group, a nitro group, or a linear or branched alkyl group having 1 to 10 carbon atoms. Furthermore, when L represents an alkylene group, the hydrogen atoms contained in one or more -CH2- groups constituting the alkylene group may be replaced by at least one group selected from the group consisting of halogen atoms, cyano groups, nitro groups, hydroxyl groups, linear alkyl groups having 1 to 10 carbon atoms, and branched alkyl groups having 1 to 10 carbon atoms. In particular, for L4, an alkylene oxy group with 4 to 6 carbon atoms and an oxygen terminal is preferred, and for L5, an ester group is most preferred.

[0108] The divalent cyclic groups represented by G1 and G2 each independently represent a divalent alicyclic hydrocarbon group or aromatic hydrocarbon group having 5 to 8 carbon atoms, and one or more of the -CH2- groups constituting the alicyclic hydrocarbon group may be substituted with -O-, -S-, or -NH-. Furthermore, multiple alicyclic hydrocarbon groups or aromatic hydrocarbon groups may be single-bonded. Among these, a benzene ring is preferred.

[0109] The terminal group represented by T4 includes hydrogen atoms, halogen atoms, cyano groups, nitro groups, hydroxyl groups, C1-C10 alkyl groups, C1-C10 alkoxy groups, C1-C10 alkylthio groups, C1-C10 alkoxycarbonyloxy groups, C1-C10 alkoxycarbonyl groups (ROC(O)-: R is an alkyl group), C1-C10 acyloxy groups, C1-C10 acylamino groups, C1-C10 alkoxycarbonylamino groups, C1-C10 sulfonylamino groups, C1-C10 sulfamoyl groups, C1-C10 carbamoyl groups, C1-C10 sulfinyl groups, C1-C10 ureido groups, and (meth)acryloyloxy group-containing groups. Among these, hydrogen atoms and cyano groups are the most preferred.

[0110] The molar ratio of repeating units F to the total is preferably 50 mol% or more from the viewpoint of orientation, and preferably 70 mol% or less from the viewpoint of repellency.

[0111] (Content) In the present invention, the amount of the surfactant described above is preferably 0.05 to 15 parts by mass, more preferably 0.08 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the liquid crystal compound, for the reason that the degree of orientation of the resulting light-absorbing anisotropic layer is higher.

[0112] <Polymerization initiator> The composition for forming the light-absorbing anisotropic layer preferably contains a polymerization initiator. There are no particular restrictions on the polymerization initiator, but it is preferable that it be a photosensitive compound, i.e., a photopolymerization initiator. Various compounds can be used as photopolymerization initiators without particular limitations. Examples of photopolymerization initiators include α-carbonyl compounds (US Patent Nos. 2,367,661 and 2,367,670), acyloin ethers (US Patent No. 2,448,828), α-hydrocarbon-substituted aromatic acyloin compounds (US Patent No. 2,722,512), polynuclear quinone compounds (US Patent Nos. 3,046,127 and 2,951,758), and combinations of triarylimidazole dimers and p-aminophenyl ketones (US Patent No. 3,549,367). Examples include acridine and phenazine compounds (Japanese Patent Publication No. 60-105667 and U.S. Patent No. 4239850), oxadiazole compounds (U.S. Patent No. 4212970), o-acyloxime compounds (see

[0065] of Japanese Patent Publication No. 2016-27384), and acylphosphine oxide compounds (Japanese Patent Publication No. 63-40799, Japanese Patent Publication No. 5-29234, Japanese Patent Publication No. 10-95788 and Japanese Patent Publication No. 10-29997). Commercially available photopolymerization initiators can also be used. Examples of commercially available photopolymerization initiators include Irgacure-184, Irgacure-907, Irgacure-369, Irgacure-651, Irgacure-819, Irgacure-OXE-01, and Irgacure-OXE-02 from BASF.

[0113] When the composition for forming a light-absorbing anisotropic layer contains a polymerization initiator, the amount of polymerization initiator is preferably 0.01 to 30 parts by mass, and more preferably 0.1 to 15 parts by mass, based on 100 parts by mass of the total of the dichroic substance and the polymer liquid crystal compound in the composition for forming the light-absorbing anisotropic layer. A polymerization initiator content of 0.01 parts by mass or more results in good durability of the light-absorbing anisotropic film, and a content of 30 parts by mass or less results in better orientation of the light-absorbing anisotropic film. Polymerization initiators may be used individually or in combination of two or more. When two or more polymerization initiators are included, it is preferable that their total amount is within the above range.

[0114] <Solvent> From the viewpoint of workability and other factors, the composition for forming the light-absorbing anisotropic layer of the present invention preferably contains a solvent. Examples of solvents include ketones (e.g., acetone, 2-butanone, methyl isobutyl ketone, cyclopetantanone, and cyclohexanone), ethers (e.g., dioxane, tetrahydrofuran, 2-methyltetrahydrofuran, cyclopentyl methyl ether, tetrahydropyran, and dioxolane), aliphatic hydrocarbons (e.g., hexane), alicyclic hydrocarbons (e.g., cyclohexane), aromatic hydrocarbons (e.g., benzene, toluene, xylene, and trimethylbenzene), halogenated carbons (e.g., dichloromethane, trichloromethane, dichloroethane, dichlorobenzene, and chlorotoluene), and esters (e.g., vinegar). Examples of solvents include organic solvents such as methyl acetate, ethyl acetate, butyl acetate, and ethyl lactate, alcohols (e.g., ethanol, isopropanol, butanol, cyclohexanol, isopentyl alcohol, neopentyl alcohol, diacetone alcohol, and benzyl alcohol), cellosolves (e.g., methyl cellosolve, ethyl cellosolve, 1,2-dimethoxyethane), cellosolve acetates, sulfoxides (e.g., dimethyl sulfoxide), amides (e.g., dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and N-ethylpyrrolidone), and heterocyclic compounds (e.g., pyridine), as well as water. These solvents may be used individually or in combination of two or more. Of these solvents, ketones (especially cyclopentanone and cyclohexanone), ethers (especially tetrahydrofuran, cyclopentyl methyl ether, tetrahydropyran and dioxolane), and amides (especially dimethylformamide, dimethylacetamide, N-methylpyrrolidone and N-ethylpyrrolidone) are preferred from the viewpoint of taking advantage of their excellent solubility.

[0115] If the composition for forming the light-absorbing anisotropic layer contains a solvent, the solvent content is preferably 80 to 99% by mass, more preferably 83 to 97% by mass, and particularly preferably 85 to 95% by mass, based on the total mass of the composition for forming the light-absorbing anisotropic layer. The solvent may be used alone or in combination of two or more. When two or more solvents are included, it is preferable that their total amount is within the above range.

[0116] <Method for forming a light-absorbing anisotropic layer> The method for forming the light-absorbing anisotropic layer is not particularly limited, and includes a method comprising, in this order, the steps of: applying the above-mentioned composition for forming the light-absorbing anisotropic layer onto the above-mentioned photo-alignment layer to form a coated film; and aligning the liquid crystal components and dichroic substances contained in the coated film. In the following description, the above-mentioned step of forming the coated film will also be referred to as the "coated film formation step," and the step of aligning the liquid crystal components and dichroic substances will also be referred to as the "alignment step." Furthermore, the term "liquid crystal component" includes not only the liquid crystal compounds mentioned above, but also, if the dichroic substance mentioned above possesses liquid crystal properties, the dichroic substance that does possess liquid crystal properties.

[0117] (Coating film formation process) The coating film formation process involves applying a composition for forming a light-absorbing anisotropic layer onto a photo-oriented layer to form a coating film. By using a composition for forming a light-absorbing anisotropic layer containing the aforementioned solvent, or by using a composition for forming a light-absorbing anisotropic layer that has been made into a liquid such as a molten liquid by heating, it becomes easier to coat the composition for forming a light-absorbing anisotropic layer onto the photo-alignment layer. Specific examples of known methods for applying a composition to form a light-absorbing anisotropic layer include, for example, roll coating, gravure printing, spin coating, wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spray coating, and inkjet coating.

[0118] (Orientation process) The orientation process is a process that aligns the liquid crystal components contained in the coated film. This results in a light-absorbing anisotropic layer. The orientation step may include a drying process. The drying process can remove components such as solvents from the coating film. The drying process may be carried out by leaving the coating film at room temperature for a predetermined time (e.g., natural drying), or by heating and / or blowing air. Here, the liquid crystal components contained in the composition for forming the light-absorbing anisotropic layer may be oriented by the coating film formation process or drying process described above. For example, in an embodiment in which the composition for forming the light-absorbing anisotropic layer is prepared as a coating solution containing a solvent, a coating film with light-absorbing anisotropy (i.e., a light-absorbing anisotropic film) is obtained by drying the coating film to remove the solvent from the coating film. If the drying process is performed at a temperature above the transition temperature of the liquid crystal components in the coated film to the liquid crystal phase, the heat treatment described later may not be necessary.

[0119] The transition temperature of the liquid crystal component in the coated film to the liquid crystal phase is preferably 10 to 250°C, and more preferably 25 to 190°C, from the viewpoint of manufacturability and other factors. A transition temperature of 10°C or higher is preferable because it eliminates the need for cooling treatment to lower the temperature to the temperature range in which the liquid crystal phase is observed. Furthermore, a transition temperature of 250°C or lower is preferable because it eliminates the need for high temperatures even when creating an isotropic liquid state at a temperature higher than the temperature range in which the liquid crystal phase is observed, thereby reducing the waste of thermal energy and the deformation and deterioration of the substrate.

[0120] The orientation step preferably includes a heat treatment. This allows the liquid crystal components contained in the coated film to be oriented, making the coated film after the heat treatment suitable for use as a light-absorbing anisotropic film. For heat treatment, a temperature of 10 to 250°C is preferred, and 25 to 190°C is more preferred, from the standpoint of suitability for manufacturing. The heating time is preferably 1 to 300 seconds, and 1 to 60 seconds is more preferred.

[0121] The orientation step may include a cooling process performed after the heat treatment. The cooling process involves cooling the heated coating film to room temperature (approximately 20-25°C). This fixes the orientation of the liquid crystal components contained in the coating film. The cooling method is not particularly limited and can be carried out by known methods. By following the above steps, a light-absorbing anisotropic film can be obtained. In this embodiment, drying treatment and heat treatment are mentioned as methods for aligning the liquid crystal components contained in the coated film, but the method is not limited to these, and can be carried out by known alignment treatments.

[0122] (Other processes) The method for forming a light-absorbing anisotropic layer may include a step of curing the light-absorbing anisotropic layer after the orientation step described above. In the following description, this step will also be referred to as the "curing step." The curing process is carried out by heating and / or light irradiation (exposure), for example, if the light-absorbing anisotropic layer has crosslinkable groups (polymerizable groups). Among these, it is preferable that the curing process be carried out by light irradiation. Various types of light can be used for curing, including infrared light, visible light, and ultraviolet light, 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. When light irradiation is performed while heating, the heating temperature during light irradiation is preferably 25 to 10°C, although this depends on the transition temperature of the liquid crystal components contained in the liquid crystal film to the liquid crystal phase. Furthermore, light irradiation may be carried out under a nitrogen atmosphere. When the curing of the liquid crystal film proceeds by radical polymerization, it is preferable to irradiate with light under a nitrogen atmosphere because the inhibition of polymerization by oxygen is reduced.

[0123] [Other Functional Layers] The laminated optical film of the present invention may have other functional layers in addition to the reflective circular polarizer, phase difference layer, and linear polarizer.

[0124] Furthermore, in order to minimize the impact on various sensors that use near-infrared light as a light source, such as eye tracking, facial expression recognition, and iris authentication, which are incorporated into the optical systems of virtual reality display devices and electronic viewfinders, it is preferable that the other functional layers are transparent to near-infrared light.

[0125] <Positive C-plate> The laminated optical film of the present invention may further preferably have a positive C plate. Here, the positive C plate is a phase difference layer in which the in-plane retardation Re is substantially zero and the retardation Rth in the thickness direction is negative. Positive C plates can be obtained, for example, by vertically oriented rod-shaped liquid crystal compounds. Details of the method for manufacturing positive C plates can be found in, for example, Japanese Patent Publication No. 2017-187732, Japanese Patent Publication No. 2016-53709, and Japanese Patent Publication No. 2015-200861. The positive C plate functions as an optical compensation layer to increase the polarization degree of transmitted and reflected light for light incident at an oblique angle. The positive C plate can be placed anywhere on the laminated optical film, and one or more plates may be installed.

[0126] The positive C plate may be placed adjacent to the reflective circular polarizer, or it may be placed inside the reflective circular polarizer. When a light-reflecting layer is used as a reflective circular polarizer, for example, by immobilizing a cholesteric liquid crystal phase containing a rod-shaped liquid crystal compound, the light-reflecting layer has a positive retardation Rth in the thickness direction. In this case, when light is incident on the reflective circular polarizer from an oblique direction, the polarization state of the reflected and transmitted light changes due to the effect of retardation Rth, and the degree of polarization of the reflected and transmitted light may decrease. In contrast, having a positive C plate inside and / or near the reflective circular polarizer is preferable because it suppresses changes in the polarization state of obliquely incident light and prevents a decrease in the polarization degree of reflected and transmitted light. According to the inventors' studies, the positive C plate is preferably placed on the side opposite to the green reflective layer relative to the blue light reflective layer, but it may be placed in other locations. In this case, the positive C plate preferably has an in-plane retardation Re of approximately 10 nm or less, and a retardation Rth in the thickness direction preferably of -600 nm to -100 nm, and more preferably of -400 nm to -200 nm.

[0127] Furthermore, the positive C plate may be placed adjacent to the phase difference layer, or it may be placed inside the phase difference layer. When a layer consisting of, for example, a rod-shaped liquid crystal compound is immobilized as the phase difference layer, the phase difference layer has a positive retardation Rth in the thickness direction. In this case, when light is incident on the phase difference layer from an oblique direction, the polarization state of the transmitted light may change due to the effect of the retardation Rth in the thickness direction, and the degree of polarization of the transmitted light may decrease. In contrast, having a positive C plate inside and / or near the phase difference layer is preferable because it can suppress changes in the polarization state of obliquely incident light and suppress a decrease in the polarization degree of transmitted light. According to the inventors' studies, the positive C plate is preferably placed on the plane opposite to the linear polarizer with respect to the phase difference layer, but it may be placed in other locations. In this case, the positive C plate preferably has an in-plane retardation Re of approximately 10 nm or less, and a thickness-direction retardation Rth of -90 nm to -40 nm.

[0128] Furthermore, the positive C plate may have a support similar to the phase difference layer and linear polarizer described above.

[0129] <Anti-reflection layer> The laminated optical film of the present invention may also preferably have an anti-reflective layer on its surface. The laminated optical film of the present invention has the function of reflecting specific circularly polarized light and transmitting circularly polarized light orthogonal to it. However, reflection on the surface of the laminated optical film generally includes reflection of unintended polarizations, thereby reducing the degree of polarization of transmitted and reflected light. For this reason, it is preferable that the laminated optical film has an anti-reflective layer on its surface. The anti-reflective layer may be applied to only one surface of the laminated optical film, or to both surfaces. While there are no particular restrictions on the type of anti-reflective layer, moth-eye films and AR films are preferred from the viewpoint of further reducing reflectivity. Furthermore, when stretching or molding the laminated optical film, moth-eye films are preferred because they can maintain high anti-reflective performance even if the film thickness changes due to stretching. On the other hand, AR films are preferred from the viewpoint of ease of wiping off dirt that adheres to the surface of the anti-reflective layer and the reduced difficulty in handling, such as damage to the surface microstructure. Furthermore, if the anti-reflective layer includes a support and is subjected to stretching and molding, etc., the support preferably has a peak Tg temperature of 170°C or lower, and more preferably 130°C or lower, from the viewpoint of facilitating stretching and molding. Specifically, for example, PMMA film is preferred.

[0130] <Second phase difference layer> The laminated optical film of the present invention may also preferably have a second phase difference layer. For example, the laminated optical film of the present invention may include a circular polarizer, a phase difference layer, a linear polarizer, and a second phase difference layer in this order. The second phase difference layer is preferably one that converts linearly polarized light to circularly polarized light, and for example, a phase difference layer having an in-plane retardation Re of 1 / 4 wavelength is preferred. The reason for this is explained below. Light incident on a laminated optical film from the side of the reflective circular polarizer, and transmitted through the reflective circular polarizer, phase difference layer, and linear polarizer, becomes linearly polarized. A portion of this light is reflected from the outermost surface on the linear polarizer side and re-emerged from the surface on the reflective circular polarizer side. Such light is unwanted reflected light and can reduce the polarization degree of the reflected light, so it is preferable to reduce it. One method to suppress reflection at the outermost surface on the linear polarizer side is to laminate an anti-reflective layer. However, when a laminated optical film is used laminated to a medium such as glass or plastic, even if an anti-reflective layer is present on the laminated surface of the laminated optical film, it cannot suppress reflection at the surface of the medium, and therefore no anti-reflective effect is obtained. On the other hand, if a second phase difference layer is installed that converts linearly polarized light into circularly polarized light, the light that reaches the outermost surface on the linear polarizer side becomes circularly polarized, and when it is reflected from the outermost surface of the medium, it is converted into orthogonal circularly polarized light. Then, when it passes through the second phase difference layer again and reaches the linear polarizer, the light becomes linearly polarized with the absorption axis orientation of the linear polarizer and is absorbed by the linear polarizer. Therefore, unwanted reflections can be prevented. From the viewpoint of more effectively suppressing unwanted reflections, it is preferable that the second phase difference layer has substantially inverse dispersion properties.

[0131] <Support> The laminated optical film of the present invention may further have a support. The support structure can be installed in any location. The support may be the support that constitutes each of the layers that make up the laminated optical film of the present invention, such as the circular polarizer, phase difference layer, linear polarizer, positive C plate, and anti-reflective layer, or it may be a support that is added separately to support the laminated optical film. Furthermore, if, for example, one or more components such as a circular polarizer, a phase difference layer, a linear polarizer, a positive C plate, and an anti-reflective layer are transferred from a temporary support to a film, the support can be used as the transfer destination. The type of support is not particularly limited, but it is preferably transparent. For example, films made of cellulose acylate, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate, cyclic polyolefin, polyolefin, polyamide, polystyrene, and polyester can be used. Among these, cellulose acylate film, cyclic polyolefin, polyacrylate, and polymethacrylate are preferred. In addition, commercially available cellulose acetate films (for example, "TD80U" and "Z-TAC" manufactured by Fujifilm Corporation) can be used as the support. Furthermore, the support preferably has a small phase difference from the viewpoint of suppressing adverse effects on the polarization degree of transmitted and reflected light, and from the viewpoint of facilitating optical inspection of the laminated optical film. Specifically, it is preferable that the size of Re is 10 nm or less, and the absolute value of the size of Rth is 50 nm or less.

[0132] When the laminated optical film of the present invention is subjected to stretching and molding, such as molding according to the shape of the lens to be combined with it, it is preferable that the support has a peak temperature of tanδ (loss tangent (loss coefficient)) of 170°C or less. From the viewpoint of enabling molding at low temperatures, the support preferably has a tanδ peak temperature of 150°C or lower, and more preferably 130°C or lower.

[0133] As described above, the laminated optical film of the present invention has a cholesteric liquid crystal layer as the light-reflecting layer of the reflective circular polarizer, and since the reflective circular polarizer does not have an optical axis, a decrease in the degree of polarization due to stretching and molding is less likely to occur. Furthermore, in a preferred embodiment, the laminated optical film of the present invention has a reflective circular polarizer having a cholesteric liquid crystal layer made of a rod-shaped liquid crystal compound and a cholesteric liquid crystal layer made of a disc-shaped compound as light-reflecting layers, thereby improving the polarization degree of reflected and transmitted light. Furthermore, in a preferred embodiment, the laminated optical film of the present invention can similarly improve the polarization degree of reflected and transmitted light by having a positive C plate.

[0134] In general, in optical applications, stretched resin substrates are often used, and this stretching process often results in high tanδ peak temperatures. For example, triacetylcellulose (TAC) substrates (e.g., TG40 manufactured by Fujifilm Corporation) have tanδ peak temperatures of 180°C or higher. In cases where a laminated optical film is stretched and molded, it is necessary to heat it to a temperature higher than the glass transition temperature (Tg) of the support before molding. However, if the heating temperature for molding is too high, each layer constituting the laminated optical film, particularly the phase difference layer and the linear polarizer, may deteriorate. For example, if the phase difference layer deteriorates, it becomes impossible to properly convert from circularly polarized light to linearly polarized light, and vice versa. Also, if the linear polarizer deteriorates, linearly polarized light in directions that it should not transmit will be transmitted. As a result, the polarization degree of light reflected and transmitted by the laminated optical film decreases, causing stray light leakage, resulting in ghosting and stray light.

[0135] In contrast, by using a support with a tanδ peak temperature of 170°C or lower, it becomes possible to perform the molding of laminated optical films at relatively low temperatures, thereby preventing degradation of the phase difference layer and linear polarizers. In other words, by using a support with a tanδ peak temperature of 170°C or lower, it becomes possible to maintain a high degree of polarization of reflected and transmitted light even when the laminated optical film is stretched and molded.

[0136] Here, we will describe the method for measuring tanδ. Using a dynamic viscoelasticity measuring device (DVA-200, manufactured by IT Measurement Control Co., Ltd.), E'' (loss modulus) and E' (storage modulus) are measured on a film sample that has been pre-conditioned for at least 2 hours at a temperature of 25°C and a humidity of 60% Rh, under the following conditions, and these values ​​are used to determine tanδ (= E'' / E'). Equipment: DVA-200 manufactured by IT Measurement & Control Co., Ltd. Sample: 5mm, 50mm length (20mm gap) Measurement conditions: Tensile mode Measurement temperature: -150℃~220℃ Heating conditions: 5°C / min Frequency: 1Hz

[0137] There are no particular restrictions on the support material as long as the peak temperature of tanδ is 170°C or lower; various resin substrates can be used. Examples include polyolefins such as polyethylene, polypropylene, and norbornene polymers; cyclic olefin resins; polyvinyl alcohol; polyethylene terephthalate; acrylic resins such as polymethacrylate and polyacrylic acid esters; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyetherketone; polyphenylene sulfide and polyphenylene oxide. In particular, cyclic olefin resins, polyethylene terephthalate, and acrylic resins are preferred due to their readily available market availability and excellent transparency, and cyclic olefin resins and polymethacrylate esters are especially preferred. Furthermore, from the viewpoint of the durability of the optical laminated film, the peak temperature of the tanδ of the support is preferably 80°C or higher.

[0138] Examples of commercially available resin substrates include Technoloy S001G, Technoloy S014G, Technoloy S000, Technoloy C001 and Technoloy C000 (Sumika Acrylic Sales Co., Ltd.), Lumirror U-type, Lumirror FX10 and Lumirror SF20 (Toray Industries, Inc.), HK-53A (Higashiyama Film Co., Ltd.), Teflex FT3 (Teijin DuPont Films Ltd.), SCSina and SCA40 (Sekisui Chemical Co., Ltd.), Zeonor Film (Optes Co., Ltd.), and Arton Film (JSR Corporation).

[0139] The thickness of the support is not particularly limited, but is preferably 5 to 300 μm, more preferably 5 to 100 μm, and even more preferably 5 to 30 μm.

[0140] As described above, the laminated optical film of the present invention has a reflective circular polarizer, a phase difference layer, and a linear polarizer in this order, and the surface roughness Ra of the surface opposite to the linear polarizer with respect to the image incident surface, i.e., the surface opposite to the linear polarizer with respect to the reflective circular polarizer, is 100 nm or less. As described above, the laminated optical film of the present invention has a surface roughness Ra of 100 nm or less on the image incident surface, which enables it to display highly sharp images when used in image display devices such as virtual reality display devices.

[0141] As described above, the surface roughness Ra of the image incident surface is the result of the superposition of the irregularities of each layer constituting the laminated optical film. In particular, when the laminated optical film has a support, the irregularities of the support greatly affect the surface roughness Ra of the image incident surface. That is, in the laminated optical film of the present invention, by using a support with few irregularities, the surface roughness Ra of the image incident surface can be suitably reduced to 100 nm or less. Therefore, when the laminated optical film of the present invention has a support, it is preferable that the surface roughness Ra of the support is small. Specifically, the surface roughness Ra of the support is preferably 50 nm or less, more preferably 30 nm or less, and even more preferably 20 nm or less.

[0142] The laminated optical film of the present invention may have multiple supports. However, as described above, considering the surface roughness Ra of the image incident surface, it is preferable to have fewer supports, preferably two or fewer layers, and particularly preferably one layer. Furthermore, for similar reasons, it is also preferable that the laminated optical film of the present invention does not have a support, provided that the entire film can be supported.

[0143] [Method of bonding each layer] The laminated optical film of the present invention is a laminate consisting of a number of layers. Each layer can be attached by any bonding method. For example, adhesives and glues can be used as bonding layers to which each layer is attached. Any commercially available adhesive can be used as the adhesive. From the viewpoint of thinning the laminated optical film and reducing the surface roughness Ra of the image incident surface of the laminated optical film, the thickness of the adhesive is preferably 25 μm or less, more preferably 15 μm or less, and even more preferably 6 μm or less. Furthermore, it is preferable that the adhesive does not easily produce outgassing. In particular, when stretching and molding are performed, vacuum processes and heating processes may be carried out, and it is preferable that no outgassing occurs even under these conditions. Any commercially available adhesive can be used as the adhesive; for example, epoxy resin-based adhesives and acrylic resin-based adhesives can be used. From the viewpoint of thinning the laminated optical film and reducing the surface roughness Ra of the image incident surface of the laminated optical film, the thickness of the adhesive is preferably 25 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. Furthermore, from the viewpoint of thinning the adhesive layer and applying the adhesive to the adherend with a uniform thickness, the viscosity of the adhesive is preferably 300 cP or less, more preferably 100 cP or less, and even more preferably 10 cP or less.

[0144] Furthermore, if the adherend has surface irregularities, the adhesive and bonding agent may be selected with appropriate viscoelasticity or thickness to embed the surface irregularities of the layer to be adhered, from the viewpoint of reducing the surface roughness Ra of the laminated optical film. From the viewpoint of embedding surface irregularities, the adhesive and bonding agent preferably have a viscosity of 50 cP or higher. Also, the thickness is preferably greater than the height of the surface irregularities. One method for adjusting the viscosity of adhesives and sealants is to use adhesives and sealants that contain a solvent. In this case, the viscosity of the adhesive can be adjusted by changing the ratio of the solvent. Furthermore, the thickness of the adhesive can be further reduced by drying the solvent after applying the adhesive to the substrate.

[0145] In laminated optical films, from the viewpoint of reducing unwanted reflections and suppressing a decrease in the polarization degree of transmitted and reflected light, it is preferable that the adhesives and bonding agents used to bond each layer have a small refractive index difference with adjacent layers. Specifically, the refractive index difference between the adhesives and bonding agents and adjacent layers is preferably 0.05 or less, and more preferably 0.01 or less. The refractive index of the adhesives and bonding agents can be adjusted, for example, by mixing titanium dioxide fine particles and zirconia fine particles. Furthermore, the circular polarizer, phase difference layer, and linear polarizer have refractive index anisotropy within the plane, but it is preferable that the refractive index difference between adjacent layers is 0.05 or less in all directions within the plane. For this reason, adhesives and bonding agents may also have refractive index anisotropy within the plane.

[0146] Furthermore, it is preferable that the bonding layer between each layer has a thickness of 100 nm or less. When the thickness of the adhesive layer is 100 nm or less, visible light does not perceive the difference in refractive index, and unwanted reflections can be suppressed. A thickness of 50 nm or less is more preferable. One method for forming an adhesive layer with a thickness of 100 nm or less is to deposit a ceramic adhesive, such as a silicon dioxide (SiOx) layer, onto the adhesive surface. The adhesive surface of the adhesive member can be subjected to surface modification treatments such as plasma treatment, corona treatment, and saponification treatment, and a primer layer can be applied before adhesion. Furthermore, if there are multiple adhesive surfaces, the type and thickness of the adhesive layer can be adjusted for each surface. Specifically, for example, an adhesive layer with a thickness of 100 nm or less can be provided by following the procedures shown in (1) to (3) below. (1) The layers to be laminated are bonded to a temporary support made of a glass substrate. (2) A SiOx layer with a thickness of 100 nm or less is formed on both the surface of the layer to be laminated and the surface of the layer to be laminated by vapor deposition or the like. Vapor deposition can be carried out using SiOx powder as the deposition source, for example, using a vapor deposition apparatus (model number ULEYES) manufactured by ULVAC, Inc. It is also preferable to apply plasma treatment to the surface of the formed SiOx layer. (3) After bonding the formed SiOx layers together, the temporary support is peeled off. Bonding is preferably carried out at a temperature of, for example, 120°C.

[0147] The application of adhesives and tacks to each layer, the formation of bonding layers such as the SiOx layer, and bonding may be carried out using a roll-to-roll method or on a sheet-to-sheet basis. The roll-to-roll method is preferable in terms of improving productivity and reducing axial misalignment in each layer. On the other hand, the single-wafer method is preferable because it is suitable for small-volume, high-mix production, and because it allows for the selection of special bonding methods, such as those described above, where the thickness of the bonding layer is 100 nm or less. Furthermore, known methods for applying adhesives and bonding agents to a substrate include, for example, roll coating, gravure printing, spin coating, wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spray coating, and inkjet coating.

[0148] [Direct application to each layer] It is also preferable that there are no adhesive layers between each layer of the laminated optical film of the present invention. When forming the layers, the adhesive layer can be eliminated by directly coating the already formed adjacent layers. Furthermore, if one or both adjacent layers contain a liquid crystal compound, it is preferable to ensure that the orientation direction of the liquid crystal compound changes continuously at the interface in order to minimize the refractive index difference in all directions within the plane. For example, a composition for forming a phase difference layer containing a liquid crystal compound can be directly applied to a linear polarizer containing a liquid crystal compound and a dichroic substance, and the orientation-regulating force of the liquid crystal compound on the linear polarizer can cause the orientation direction of the liquid crystal compound in the phase difference layer to be continuous with that of the linear polarizer at the interface.

[0149] [Layer stacking order] The laminated optical film of the present invention consists of a number of layers, but there are no particular restrictions on the order in which they are laminated, and the order can be arbitrarily selected. For example, when transferring a functional layer from a film consisting of a temporary support and a functional layer, the occurrence of wrinkles and cracks during transfer can be prevented by adjusting the lamination order so that the thickness of the destination film is 10 μm or more. Furthermore, when another layer is laminated on top of a layer with large surface irregularities, the surface irregularities may be further amplified. Therefore, from the viewpoint of reducing the surface roughness Ra of the image incident surface of the laminated optical film, it is preferable to laminate the layers in order from the layer with the smallest surface roughness Ra. Furthermore, the order of lamination can be selected from the perspective of quality evaluation during the manufacturing process of the laminated optical film. For example, the layers excluding the reflective circular polarizer can be laminated, and quality evaluation can be performed using a transmission optical system, after which the reflective circular polarizer can be laminated and quality evaluation can be performed using a reflection optical system. Furthermore, the lamination order can be selected to improve the manufacturing yield of laminated optical films and reduce costs.

[0150] [Applications of the Laminated Optical Film of the Present Invention] The laminated optical film of the present invention can be suitably used as a reflective polarizer incorporated into image display devices such as in-vehicle rearview mirrors, virtual reality display devices, augmented reality display devices, mixed reality display devices, electronic viewfinders, and aerial image display devices, as described in Patent Documents 4 to 6, for example. In particular, in virtual reality display devices and electronic viewfinders having a reciprocating optical system that reflects and moves light back and forth between a reflective polarizer and a half-mirror, the laminated optical film of the present invention is extremely useful in terms of improving the clarity of the displayed image. Furthermore, virtual reality display devices and electronic viewfinders having a reciprocating optical system may also have optical films such as absorptive polarizers and circular polarizers in addition to reflective polarizers, but by using some of the components and bonding methods used in the laminated optical film of the present invention in optical films other than the reflective polarizer mentioned above, the clarity of the displayed image can be further improved. [Examples]

[0151] The features of the present invention will be further described in detail below with reference to examples. The materials, amounts used, proportions, processing content, and processing procedures shown below can be modified as appropriate, as long as they do not depart from the spirit of the present invention. Furthermore, configurations other than those shown below are also possible, as long as they do not depart from the spirit of the present invention.

[0152] [Fabrication of Reflecting Circular Polarizer 1] A 50 μm thick PET (polyethylene terephthalate) film (A4100, manufactured by Toyobo Co., Ltd.) was prepared as a temporary support. This PET film has an easy-adhesion layer on one side.

[0153] The compositions shown below were stirred and dissolved in a container kept at 70°C to prepare coating solutions Ch-A, Ch-B, and Ch-C for the light-reflecting layer, respectively.

[0154] ------------------------------------------------------------------ Coating solution for light-reflecting layer Ch-A ------------------------------------------------------------------ Methyl ethyl ketone 120.9 parts by mass Cyclohexanone 21.3 parts by mass • 100.0 parts by mass of the following mixture of rod-shaped liquid crystal compounds • Photopolymerization initiator B: 1.00 parts by mass • 2.50 parts by mass of the following chiral agent A • The following surfactant F1: 0.027 parts by mass • The following surfactant F2: 0.067 parts by mass ------------------------------------------------------------------

[0155] (Coating solution for light-reflecting layer Ch-B) The solution was prepared in the same manner as the coating solution Ch-A for the light-reflecting layer, except that the chiral agent A was 3.50 parts by mass.

[0156] (Coating solution for light-reflecting layer Ch-C) The solution was prepared in the same manner as the coating solution Ch-A for the light-reflecting layer, except that the chiral agent A was 4.50 parts by mass.

[0157] Rod-shaped liquid crystal compound mixture

[0158] [ka] In the above mixture, the values ​​are in mass percent. R represents a group bonded to an oxygen atom. Furthermore, the average molar extinction coefficient of the above rod-shaped liquid crystal compound at wavelengths of 300-400 nm was 140 / mol·cm.

[0159] Chiral agent A

[0160] [ka]

[0161] Surfactant F1

[0162] [ka]

[0163] Surfactant F2

[0164] [Chemistry]

[0165] Photoinitiator B

[0166] [Chemistry]

[0167] [[ID=​​​​​​​​​​​​​​​​​​​​When cross-sections of the fabricated red light reflective layer, green light reflective layer, and blue light reflective layer were observed using a scanning electron microscope (SEM), striped patterns of light and dark areas were observed in all of them. However, the spacing between the light and dark areas of the striped pattern in the cholesteric liquid crystal layer did not change within the layer.

[0172] Furthermore, the thickness of the cholesteric liquid crystal layers for the red light reflective layer, the green light reflective layer, and the blue light reflective layer was 4 μm each. In the circular polarizer 1, the red light reflective layer, the green light reflective layer, and the blue light reflective layer are all cholesteric liquid crystal layers made of rod-shaped liquid crystal compounds.

[0173] Furthermore, the surface roughness Ra of the red light reflective layer, green light reflective layer, and blue light reflective layer on the temporary support side was 20 nm or less in all cases. The surface roughness Ra (arithmetic mean roughness Ra) was measured using the VertScan non-contact surface and layer cross-sectional shape measurement system (manufactured by Ryoka Systems Co., Ltd.). Specifically, the side of the film to be measured opposite to the measurement surface was bonded to a smooth glass substrate with a 5 μm thick adhesive, and the surface irregularities were measured. The surface roughness Ra was calculated from the irregularity data in an area of ​​approximately 4 mm square. In this case, Eagle XG glass substrate (0.7 μm thick, manufactured by Corning) and NCF-D692 adhesive (5 μm thick, manufactured by Lintec Corporation) were used. The same procedure was followed for the measurement of surface roughness Ra described below.

[0174] [Fabrication of Reflecting Circular Polarizer 2] (Coating solution for light-reflecting layer Ch-D) The following compositions were stirred and dissolved in a container kept at 50°C to prepare coating solution Ch-D for the light-reflecting layer.

[0175] ------------------------------------------------------------------ Coating solution for light-reflecting layer Ch-D ------------------------------------------------------------------ • 80 parts by mass of the following disc-shaped liquid crystal compound (A) · 20 parts by mass of the following discotic liquid crystal compound (B) · 10 parts by mass of the polymerizable monomer E1 · 0.3 parts by mass of the surfactant F4 · 3 parts by mass of a photoinitiator (manufactured by BASF, Irgacure 907) · 4.30 parts by mass of the chiral agent A · 290 parts by mass of methyl ethyl ketone · 50 parts by mass of cyclohexanone ―――――――――――――――――――――――――――――――――

[0176] Discotic liquid crystal compound (A)

[0177]

Chemical formula

[0178] Discotic liquid crystal compound (B)

[0179]

Chemical formula

[0180] Polymerizable monomer E1

[0181]

Chemical formula

[0182] Surfactant F4

[0183]

Chemical formula

[0184] The surface of the previously shown PET film (temporary support) without the easy adhesion layer was subjected to rubbing treatment, and after applying the coating liquid Ch-C for the light reflection layer prepared above with a wire bar coater, it was dried at 110 °C for 120 seconds. Then, in a low oxygen atmosphere (100 ppm or less), at 100 °C, with an illuminance of 80 mW and an irradiation dose of 500 mJ / cm2 A blue light reflective layer consisting of a cholesteric liquid crystal layer was formed by irradiating it with light from a metal halide lamp. In all cases, the light irradiation was performed from the cholesteric liquid crystal layer side.

[0185] Next, the light-reflecting coating solution Ch-A was applied to the blue light-reflecting layer using a wire bar coater, and then dried at 110°C for 120 seconds. After that, under a low-oxygen atmosphere (less than 100 ppm), the material was exposed to light at 100°C with an illuminance of 80 mW and an irradiation dose of 500 mJ / cm². 2 By irradiating the blue light-reflecting layer with light from a metal halide lamp, a red light-reflecting layer consisting of a cholesteric liquid crystal layer was formed on top of the blue light-reflecting layer. In all cases, the light irradiation was performed from the cholesteric liquid crystal layer side.

[0186] Next, the red light reflective layer surface was subjected to a discharge rate of 150 W·min / m 2 Corona treatment was performed, and the light-reflecting layer coating solution Ch-D was applied to the corona-treated surface using a wire bar. Next, the coated film was dried at 70°C for 2 minutes to vaporize the solvent, and then heated and aged at 115°C for 3 minutes to obtain a uniform orientation. After that, the coated film was kept at 45°C and irradiated with ultraviolet light (300 mJ / cm²) using a high-pressure mercury lamp under a nitrogen atmosphere. 2 A green light reflective layer consisting of a cholesteric liquid crystal layer was fabricated on a red light reflective layer.

[0187] When the cross-section of the fabricated laminated film was observed using a scanning electron microscope (SEM), a striped pattern of light and dark areas was observed. Specifically, a layer with a constant stripe spacing corresponding to the blue light reflective layer was observed from the PET film (temporary support) side, a layer with a constant stripe spacing corresponding to the red light reflective layer was observed, a layer with a constant stripe spacing corresponding to the red light reflective layer was observed, a layer with a constant stripe spacing corresponding to the green light reflective layer was observed, and a layer with a constant stripe spacing was observed, totaling 2.9 μm. In the circular polarizer 2, both the red light reflective layer and the blue light reflective layer are cholesteric liquid crystal layers made of rod-shaped liquid crystal compounds, while the green light reflective layer is a cholesteric liquid crystal layer made of disc-shaped liquid crystal compounds.

[0188] Furthermore, the surface roughness Ra of the temporary support side of the fabricated laminated film was 20 nm or less.

[0189] [Fabrication of Positive C Plate 1] A positive C plate 1 was prepared by adjusting the film thickness, referring to the method described in paragraphs 0132 to 0134 of Japanese Patent Publication No. 2016-053709. However, the support was changed from polyethylene terephthalate film (PET film) to triacetylcellulose film (TAC film). The surface roughness Ra of the liquid crystal layer side of this TAC film was 22 nm. Positive C plate 1 had an in-plane retardation Re = 0.2 nm and a thickness-direction retardation Rth = -310 nm.

[0190] [Fabrication of Phase Difference Layer 1] Referring to the method described in paragraphs 0151 to 0163 of Japanese Patent Publication No. 2020-084070, a reverse-dispersible phase difference layer 1 was prepared on a cellulose acylate film to serve as a temporary support. Phase difference layer 1 had an in-plane retardation Re=146nm and a thickness-direction retardation Rth=73nm.

[0191] [Fabrication of Positive C Plate 2] Positive C plate 2 was prepared in the same manner as positive C plate 1, except for adjusting the film thickness. Note that while TAC film was used as the support for positive C plate 1, PET film was used as the temporary support for positive C plate 2. Positive C plate 2 had an in-plane retardation Re = 0.1 nm and a thickness-direction retardation Rth = -70 nm.

[0192] [Fabrication of Linear Polarizer 1]

[0193] <Preparation of Cellulose Acrylate Film 1> (Preparation of cellulose acylate-doped core layer) The following compositions were placed in a mixing tank and stirred to dissolve each component, preparing a cellulose acetate solution to be used as a cellulose acylate dope for the core layer. ------------------------------------------------------------------ Core layer cellulose acylate doped ------------------------------------------------------------------ • 100 parts by mass of cellulose acetate with an acetyl substitution degree of 2.88 • Examples in Japanese Patent Publication No. 2015-227955 12 parts by mass of the listed polyester compound B • Compound F below: 2 parts by mass • Methylene chloride (first solvent) 430 parts by mass • Methanol (second solvent) 64 parts by mass ------------------------------------------------------------------

[0194] Compound F

[0195] [ka]

[0196] (Preparation of outer layer cellulose acylate dope) A cellulose acetate solution to be used as the outer layer cellulose acylate dope was prepared by adding 10 parts by mass of the following mat agent solution to 90 parts by mass of the above-mentioned core layer cellulose acylate dope.

[0197] ------------------------------------------------------------------ Mat solution ------------------------------------------------------------------ • Silica particles with an average particle size of 20 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 2 parts by mass • Methylene chloride (first solvent) 76 parts by mass • Methanol (second solvent) 11 parts by mass • 1 part by mass of the above-mentioned core layer cellulose acylate doped ------------------------------------------------------------------

[0198] (Preparation of Cellulose Acrylate Film 1) After filtering the above-mentioned core layer cellulose acylate dope and the above-mentioned outer layer cellulose acylate dope through filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm, the core layer cellulose acylate dope and the outer layer cellulose acylate dope on both sides were simultaneously cast from the casting port onto a drum at 20°C (band casting machine). Next, the film was peeled off with a solvent content of approximately 20% by mass, and both ends in the width direction of the film were fixed with tenter clips. The film was then dried while being stretched transversely at a stretching ratio of 1.1 times. Subsequently, the film was further dried by transporting it between the rolls of a heat treatment apparatus to produce an optical film with a thickness of 40 μm, which was designated as cellulose acylate film 1. The in-plane retardation of the obtained cellulose acylate film 1 was 0 nm.

[0199] <Fabrication of photo-aligned film 1>

[0200] The orientation layer forming coating liquid PA1, described later, was continuously applied to the cellulose acylate film 1 (temporary support) using a wire bar. The support with the coated film was dried with 140°C hot air for 120 seconds, and then polarized ultraviolet light (10 mJ / cm²) was irradiated onto the coating film. 2 By using an ultra-high pressure mercury lamp, a photo-alignment layer PA1 was formed, and a photo-alignment film 1 was obtained. The film thickness was 0.3 μm.

[0201] ------------------------------------------------------------------ (PA1 coating solution for forming an orientation layer) ------------------------------------------------------------------ • 100.00 parts by mass of the polymer PA-1 described below • Acid generator PAG-1: 5.00 parts by mass • The following acid generator CPI-110TF: 0.005 parts by mass Xylene 1220.00 parts by mass • Methyl isobutyl ketone 122.00 parts by mass ------------------------------------------------------------------

[0202] Polymer PA-1

[0203] [ka]

[0204] Acid Generator PAG-1

[0205] [ka]

[0206] Acid Generator CPI-110F

[0207] [ka]

[0208] <Formation of light-absorbing anisotropic layer P1> On the obtained orientation layer PA1, a composition P1 for forming the following light-absorbing anisotropic layer was continuously coated using a wire bar to form the coated layer P1. Next, the coated layer P1 was heated at 140°C for 30 seconds, and then cooled to room temperature (23°C). Next, it was heated at 90°C for 60 seconds and then cooled again to room temperature. Subsequently, an illuminance of 200 mW / cm was measured using an LED lamp (center wavelength 365 nm). 2 By irradiating under these conditions for 2 seconds, a light-absorbing anisotropic layer P1 was formed on the orientation layer PA1, thereby fabricating a linear polarizer 1. The thickness of the light-absorbing anisotropic layer P1 was 1.6 μm.

[0209] ------------------------------------------------------------------ Composition of composition P1 for forming a light-absorbing anisotropic layer ------------------------------------------------------------------ • 0.25 parts by mass of the following dichroic substance D-1 • The following dichroic substance D-2: 0.36 parts by mass • The following dichroic substance D-3: 0.59 parts by mass • 2.21 parts by mass of the following polymer liquid crystal compound P-1 • 1.36 parts by mass of the following low molecular weight liquid crystal compound M-1 • Polymerization initiator IRGACUREOXE-02 (manufactured by BASF) 0.200 parts by mass • Surfactant F-1: 0.026 parts by mass Cyclopentanone 46.00 parts by mass • Tetrahydrofuran 46.00 parts by mass Benzyl alcohol 3.00 parts by mass ------------------------------------------------------------------

[0210] Dichroic substance D-1

[0211] [ka]

[0212] Dichroic substance D-2

[0213] [ka]

[0214] Dichroic substance D-3

[0215] [ka]

[0216] Polymer liquid crystal compound P-1

[0217] [ka]

[0218] Low molecular liquid crystal compound M-1

[0219] [ka]

[0220] Surfactant F-1

[0221] [ka]

[0222] [Fabrication of Linear Polarizer 2] Referring to the method for producing a thin polarizing film with a resin substrate described in the examples of Japanese Patent Publication No. 2015-129826, a linear polarizer 2 containing a 4 μm thick PVA layer was formed on a PET film to serve as a temporary support.

[0223] [Fabrication of Phase Difference Layer 2] Referring to the method described in paragraphs 0108 to 0109 of Japanese Patent Publication No. 2020-76968, a phase difference layer 2 made of a polycarbonate resin and having inverse dispersion with respect to wavelength was fabricated. The Re of phase difference layer 2 was 140 nm.

[0224] [Example 1] The light-reflecting layers fabricated with the reflective circular polarizer 1 were transferred to the support (TAC) of the fabricated positive C plate 1 in the order of blue light reflection layer, green light reflection layer, and red light reflection layer from the support side, and then laminated. The transfer of each light-reflecting layer was performed according to the following procedure. (1) The layers to be laminated were bonded to a temporary support made of a glass substrate, and the temporary support (PET film) used to form the light-reflective layer was peeled off. (2) A 50 nm thick SiOx layer was deposited onto both the surface of the layer to be laminated and the surface of the layer to be laminated. The deposition was carried out using SiOx powder as the deposition source and an ULVAC deposition apparatus (model number ULEYES). Subsequently, the surface of the formed SiOx layer was plasma treated. (3) After bonding the formed SiOx layers together at 120°C, the temporary support (glass substrate) was peeled off. Next, the positive C plate 2 was laminated onto the red light reflective layer using the same procedure (1) to (3) as described above. Next, the phase difference layer 1 was laminated onto the positive C plate 2 using the same procedure (1) to (3) as described above. Finally, a linear polarizer 1 (optical absorption anisotropy layer P1) was stacked on the phase difference layer 1 using the same procedure (1) to (3) as described above. However, the stacking was done so that the slow axis of the phase difference layer 1 and the absorption axis of the optical absorption anisotropy layer P1 formed a 45° angle, and the polarization axis of the light emitted from the phase difference layer 1 and the transmission axis of the optical absorption anisotropy layer P1 were parallel. In this way, the laminated optical film of Example 1 was fabricated. In this Example 1, the surface roughness Ra of the positive C plate, which serves as the image incident surface, was measured. The image incident surface is, as described above, the surface of the laminated optical film opposite the linear polarizer to the circular polarizer. As a result, the surface roughness Ra of the image incident surface, i.e., the positive C plate, was 30 nm. As mentioned above, the surface roughness Ra of the liquid crystal layer side of the TAC film that serves as the support is 22 nm.

[0225] [Example 2] The green light reflective layer of the fabricated circular polarizer 2 was bonded to a temporary support made of a glass substrate, and the temporary support (PET film) used to form the circular polarizer 2 was peeled off to expose the blue light reflective layer. A positive C plate 2 was laminated onto this blue light reflective layer using the same procedure (1) to (3) as in Example 1. Next, the phase difference layer 1 was laminated onto the positive C plate 2 using the same procedure (1) to (3) as in Example 1. Furthermore, a linear polarizer 1 (optical absorption anisotropy layer P1) was stacked on the phase difference layer 1 using the same procedure (1) to (3) as in Example 1. However, the stacking was performed such that the slow axis of the phase difference layer 1 and the absorption axis of the optical absorption anisotropy layer P1 formed a 45° angle, and the polarization axis of the light emitted from the phase difference layer 1 and the transmission axis of the optical absorption anisotropy layer P1 were made parallel. On the other hand, we prepared "MASTACK, AS3-304" manufactured by Fujimori Kogyo Co., Ltd. This is an anti-reflective film made by providing an anti-reflective layer consisting of a moth-eye layer on a TAC support. The surface roughness Ra on the moth-eye layer side of the TAC support of this anti-reflective film was 25 nm. A temporary support made of a glass substrate attached to the reflective circular polarizer 2 was peeled off, and the TAC support of the anti-reflective film and the green light reflective layer exposed by peeling off the glass substrate were laminated using the same procedure (2) to (3) as in Example 1 to produce the laminated optical film of Example 2. In this Example 2 of the laminated optical film, the surface roughness Ra of the moth-eye layer, which serves as the image incident surface, was measured. As a result, the surface roughness Ra of the image incident surface was found to be 30 nm.

[0226] [Example 3] The laminated optical film of Example 3 was fabricated in the same manner as in Example 1, except that linear polarizer 1 (light-absorbing anisotropic layer P1) was replaced with linear polarizer P2. In this Example 3 of the laminated optical film, the surface roughness Ra of the positive C plate, which serves as the image incident surface, was measured. As a result, the surface roughness Ra of the image incident surface was 60 nm.

[0227] [Example 4] The laminated optical film of Example 4 was fabricated in the same manner as in Example 1, except that phase difference layer 1 was replaced with phase difference layer 2. In this Example 4, the surface roughness Ra of the positive C plate, which serves as the image incident surface, was measured. As a result, the surface roughness Ra of the image incident surface was 35 nm.

[0228] [Example 5] The laminated optical film of Example 5 was fabricated in the same manner as in Example 1, except that linear polarizer 1 (light absorption anisotropy layer P1) was replaced with linear polarizer P2, and phase difference layer 1 was replaced with phase difference layer 2. In this Example 4, the surface roughness Ra of the positive C plate, which serves as the image incident surface, was measured. As a result, the surface roughness Ra of the image incident surface was 65 nm.

[0229] [Example 6] A laminated optical film of Example 6 was fabricated in the same manner as in Example 2, except that the positive C plate 2 was not laminated, the phase difference layer 1 was laminated on the blue light reflective layer, and the linear polarizer 1 was laminated on top of that. In the laminated optical film of this Example 6, the surface roughness Ra of the moth-eye layer, which serves as the image incident surface, was measured. As a result, the surface roughness Ra of the image incident surface was 30 nm.

[0230] [Example 7] An anti-reflective film was prepared by providing an anti-reflective layer consisting of a moth-eye layer on a polymethyl methacrylate (PMMA) support (75 μm thick). The moth-eye layer was the same as that used in Example 2. In this anti-reflective film, the surface roughness Ra of the moth-eye layer on the PMMA support was 20 nm.

[0231] The green light reflective layer of the fabricated reflective circular polarizer 2 and the support (PMMA) of the anti-reflective film were laminated using the same procedure (2) to (3) as in Example 1. Next, the temporary support (PET film) of the reflective circular polarizer 2 was peeled off, and the positive C plate 2 was laminated onto the exposed blue light reflective layer using the same procedure (1) to (3) as in Example 1. Next, the phase difference layer 1 was laminated onto the positive C plate 2 using the same procedure (1) to (3) as in Example 1. Finally, the linear polarizer 1 (optical absorption anisotropy layer P1) was stacked on the phase difference layer 1 using the same procedure (1) to (3) as in Example 1. However, the stacking was performed such that the slow axis of the phase difference layer 1 and the absorption axis of the optical absorption anisotropy layer P1 formed a 45° angle, and the polarization axis of the light emitted from the phase difference layer 1 and the transmission axis of the optical absorption anisotropy layer P1 were made parallel. This allowed us to fabricate the laminated optical film of Example 7. In the laminated optical film of this Example 7, the surface roughness Ra of the moth-eye layer, which serves as the image incident surface, was measured. As a result, the surface roughness Ra of the image incident surface was 30 nm.

[0232] [Example 8] An anti-reflective film identical to that in Example 7 was prepared, except that it had a cyclic olefin resin (COP) support (100 μm thick) instead of a polymethyl methacrylate support. The laminated optical film of Example 8 was prepared in the same manner as in Example 7, except that this anti-reflective film was used. The surface roughness Ra on the moth-eye layer side of the COP support for the anti-reflective film was 20 nm. In the laminated optical film of this Example 8, the surface roughness Ra of the moth-eye layer, which serves as the image incident surface, was measured. As a result, the surface roughness Ra of the image incident surface was 30 nm.

[0233] [Example 9] The laminated optical film of Example 9 was fabricated in the same manner as in Example 7, except that the positive C plate 2 was not laminated, the phase difference layer 1 was laminated on the blue light reflective layer, and the linear polarizer 1 was laminated on top of that. In the laminated optical film of this Example 9, the surface roughness Ra of the moth-eye layer, which serves as the image incident surface, was measured. As a result, the surface roughness Ra of the image incident surface was found to be 30 nm.

[0234] [Example 10] To the linear polarizer of the laminated optical film of Example 7, a second phase difference layer 1 was further laminated using the same procedure (1) to (3) as in Example 1 to produce the laminated optical film of Example 10. Furthermore, this second phase difference layer was stacked so that the orientation of its slow phase axis was the same as that of the slow phase axis of the first phase difference layer. In the laminated optical film of this Example 10, the surface roughness Ra of the moth-eye layer, which serves as the image incident surface, was measured. As a result, the surface roughness Ra of the image incident surface was 30 nm.

[0235] [Comparative Example 1] An Apple iPad® tablet computer was disassembled, and a polarizing plate was removed from the backlight side of the liquid crystal cell. The removed polarizing plate consisted of a reflective linear polarizer and a linear polarizer stacked from the incident side. The reflective linear polarizer was a film (APF) made from a stretched dielectric multilayer, and the linear polarizer contained a stretched polyvinyl alcohol (PVA) film dyed with iodine. The phase difference layer 1 described above was attached to the surface of the reflective linear polarizer of the peeled polarizer using an adhesive so that the slow axis of the phase difference layer 1 and the reflection axis of the reflective linear polarizer formed a 45° angle, and then transferred. In this way, a laminated optical film of Comparative Example 1, which functions as a reflective circular polarizer, was fabricated. In this Comparative Example 1, the layer corresponding to the image incident surface is phase difference layer 1 (1 / 4λ layer (coated)). The surface roughness Ra of the image incident surface was 160 nm.

[0236] [Comparative Example 2] A laminated optical film of Comparative Example 2 was fabricated in the same manner as in Example 1, except that the support (TAC) of the positive C plate 1 was a TAC film with a surface roughness Ra of 65 nm on the liquid crystal layer side. In this Comparative Example 2, the surface roughness Ra of the positive C plate, which serves as the image incidence surface, was measured. As a result, the surface roughness Ra of the image incidence surface was 120 nm.

[0237] <Evaluation of Polarization Degree> The polarization degrees of the transmitted and reflected light from the obtained laminated optical film were measured using the following method. A circular polarizer, consisting of a quarter-wave plate and a linear polarizer, was attached to the light-receiving section of a "Goniophotometer" manufactured by Murakami Color Materials Research Institute Co., Ltd. A laminated optical film was placed on the stage, and unpolarized light with a wavelength of 550 nm was incident on the reflective surface. Next, the light-receiving section was rotated, and the amount of transmitted and reflected light from the laminated optical film was measured. The transmittance and reflectance for right-circularly polarized light were calculated by dividing these measurements by the amount of incident light. Furthermore, the circular polarizer attached to the light-receiving section was changed, and the same measurements were performed to calculate the transmittance and reflectance for left-circularly polarized light. Here, the transmittance of right-circularly polarized light is denoted as Tr, and the transmittance of left-circularly polarized light is denoted as Tl. The polarization degree Pct of the transmitted light was calculated according to the following formula (2). Equation (2): Pct = |(Tr-Tl) / (Tr+Tl)| Here, Rr is the reflectance of right-circularly polarized light, and Rl is the reflectance of left-circularly polarized light. The degree of polarization Pcr of the reflected light was calculated according to the following formula (3). Equation (3): Pcr = |(Rr-Rl) / (Rr+Rl)| The results are shown in the table below.

[0238] <Evaluation of polarization degree after molding> For the laminated optical films of Examples 6-10 and Comparative Example 1, the degree of polarization after molding was also measured. Specifically, the laminated optical film to be measured was cut to 200 mm x 300 mm, and a convex lens with a diameter of 50 mm and a thickness of 10 mm was used as a mold. Vacuum forming was performed using the method described in Japanese Patent Application Publication No. 2012-116094. The forming temperature was 110°C. The degree of polarization was measured on the molded laminated optical film using the same method as described above. The results are shown in Table 1 below.

[0239] <Evaluation of image sharpness and ghosting> We disassembled the lens of the Huawei VR Glass, a virtual reality display device manufactured by Huawei that employs a reciprocating optical system, and removed the lens closest to the viewer. This lens is a plano-convex lens with a convex surface on the viewing side, and a circular polarizer was bonded to the flat side. Next, the circular polarizer was removed from the lens, and in its place, the laminated optical films of Examples 1-10 and Comparative Examples 1-2 were laminated so that the linear polarizer side was the viewing side. The aforementioned lens was then reassembled into the main body to create a virtual reality display device.

[0240] In the fabricated virtual reality display device, a black and white checkerboard pattern was displayed on the image display panel, and image sharpness and ghosting were evaluated visually. Regarding image sharpness, A indicates that the black and white checkerboard pattern was clearly visible across the entire lens area. B indicates that the black and white checkerboard pattern was clearly visible across the entire lens area. We rated the pattern as C if the black and white checkerboard pattern was unclear. Also, regarding ghosts, A indicates that no ghosting was visible across the entire lens area. Some ghosting was observed across the entire lens area, but those that do not pose a practical problem are rated B. For practical purposes, we rated images with visible ghosting as C. The results are shown in the table below.

[0241] The table below also shows the layer configuration of each laminated optical film. In the layer configuration shown in the table below, the positive C layer refers to the positive C plate. Support (TAC) refers to a support made of triacetylcellulose, Support (PMMA) refers to a support made of polymethyl methacrylate, and Support (COP) refers to a support made of cyclic olefin resin. The rod shape indicates that the liquid crystal compound forming the reflective layer (cholesteric liquid crystal layer) is a rod-shaped liquid crystal compound, and the disc shape indicates that the liquid crystal compound forming the reflective layer (cholesteric liquid crystal layer) is a disc-shaped liquid crystal compound. The 1 / 4λ layer (coated) refers to phase difference layer 1, i.e., the 1 / 4λ layer formed by the coating method, and the 1 / 4λ layer (PC) refers to phase difference layer 2, i.e., the 1 / 4λ layer made of polycarbonate resin. Furthermore, the linear polarizer layer (coated) refers to linear polarizer layer 1 (light absorption anisotropy layer P1), i.e., a linear polarizer formed by the coating method, and the linear polarizer layer (PVA) refers to linear polarizer layer 2, i.e., a linear polarizer containing a PVA layer.

[0242] [Table 1] In the table above, for Comparative Example 1, the surface roughness Ra of the support was not measured because the reflective linear polarizer (APF) itself acts as the support.

[0243] As shown in the table above, all of the laminated optical films of the present invention, in which the surface roughness Ra of the image incident surface is 100 nm or less, achieve very high image sharpness in the black and white checker pattern across the entire lens area. In contrast, the laminated optical films of the comparative examples, in which the surface roughness Ra of the image incident surface exceeds 100 nm, show an unclear black and white checker pattern and low image sharpness. Furthermore, as shown in Comparative Example 1, when the surface roughness Ra of the support is large, the surface roughness Ra of the image incident surface also increases. As shown in Examples 2 and 6, and Examples 7 and 9, the laminated optical film of the present invention can, if necessary, use a positive C plate to increase the polarization degree of reflected and transmitted light, and as a result can display an image with very little ghosting. As shown in Examples 1, 2, 7, and 8, the laminated optical film of the present invention has a circular polarizer with a light-reflecting layer made of a rod-shaped liquid crystal compound and a light-reflecting layer made of a disc-shaped liquid crystal compound. This allows for a higher degree of polarization to be obtained even with a smaller number of positive C plates compared to a circular polarizer with all light-reflecting layers made of rod-shaped liquid crystal compounds. As shown in Example 10, by further having a second phase difference layer on the surface of the linear polarizer, reflection on the observation side surface can be prevented, and the polarization degree of the reflected light can be improved. Furthermore, as shown in Examples 6 to 10, the laminated optical film of the present invention uses a resin substrate with a tanδ peak temperature of 170°C or lower as a support, which enables molding even at low temperatures. As a result, even when molded according to, for example, the shape of a lens, it is possible to prevent a decrease in the polarization degree of reflected and transmitted light after molding. Based on the above results, the effects of the present invention are clear. [Explanation of symbols]

[0244] 100-layer optical film 101 Anti-reflection layer 102 Positive C plate 103 Reflecting circular polarizer 104 Positive C plate 105 Retardation layer 106 Linear polarizer 300 Half Mirror 400 yen polarizer 500 Image Display Panel 1000 Rays that form virtual images 2000 Rays that form ghosts

Claims

1. At a minimum, the device comprises one or more functional layers including a positive C plate, a support, a reflective circular polarizer, a phase difference layer that converts circularly polarized light to linearly polarized light, and a linear polarizer, in this order, and all layers, including the one or more functional layers, the support, the reflective circular polarizer, the phase difference layer, and the linear polarizer, are laminated in contact with adjacent layers. A laminated optical film wherein the surface roughness Ra of the surface opposite to the linear polarizer relative to the reflective circular polarizer is 100 nm or less.

2. The laminated optical film according to claim 1, having the support having a surface roughness Ra of 50 nm or less.

3. The laminated optical film according to claim 2, wherein the support is a resin substrate having a tanδ peak temperature of 170°C or less.

4. The laminated optical film according to any one of claims 1 to 3, wherein the reflective circular polarizer has at least a light-reflecting layer on which a cholesteric liquid crystal phase is immobilized.

5. The laminated optical film according to any one of claims 1 to 4, wherein the reflective circular polarizer comprises at least a blue light reflective layer having a reflectivity of 40% or more for light with a wavelength of 450 nm, a green light reflective layer having a reflectivity of 40% or more for light with a wavelength of 530 nm, and a red light reflective layer having a reflectivity of 40% or more for light with a wavelength of 630 nm.

6. The laminated optical film according to claim 5, wherein the reflective circular polarizer further has an infrared light reflective layer having a reflectance of 40% or more for light with a wavelength of 800 nm.

7. The laminated optical film according to any one of claims 1 to 6, wherein the reflective circular polarizer comprises at least a light-reflecting layer having a cholesteric liquid crystal phase containing a rod-shaped liquid crystal compound immobilized on it, and a light-reflecting layer having a cholesteric liquid crystal phase containing a disc-shaped liquid crystal compound immobilized on it.

8. The laminated optical film according to any one of claims 1 to 7, wherein the phase difference layer has substantially inverse dispersion with respect to wavelength.

9. The laminated optical film according to any one of claims 1 to 8, wherein the phase difference layer has at least a layer on which a uniformly oriented liquid crystal compound is immobilized.

10. The laminated optical film according to any one of claims 1 to 9, wherein the phase difference layer has at least a layer on which a liquid crystal compound is immobilized, which is twisted and oriented with the thickness direction as the helical axis.

11. The laminated optical film according to any one of claims 1 to 10, wherein the linear polarizer consists of a layer with a thickness of 10 μm or less.

12. The laminated optical film according to any one of claims 1 to 11, wherein the linear polarizer has a light-absorbing anisotropic layer containing at least a liquid crystal compound and a dichroic substance.

13. Furthermore, the laminated optical film according to any one of claims 1 to 12, wherein one of the surfaces has an anti-reflective layer.

14. The laminated optical film according to claim 13, wherein the anti-reflective layer is a moth-eye film or an AR film.

15. An image display device comprising a laminated optical film according to any one of claims 1 to 14 and an image display element.

16. Furthermore, it has a half-mirror, The image display device according to claim 15, comprising the image display element, the half mirror, and the laminated optical film in this order.

17. The image display device according to claim 15 or 16, which is a virtual reality display device.

Images