JP2019179204A - Anisotropic optical film - Google Patents

Abstract

To provide an anisotropic optical film in which the diffusibility of light emitted from other surfaces changes depending on an incident angle of light entering from one surface.SOLUTION: The anisotropic optical film includes: a matrix part A(10); and a columnar part B(20) extending from one surface toward other surfaces, in which the diameter and major axis length of a cross sectional shape in a plane parallel to the plane direction and the length of longest within the cross sectional shape or the length of longest in a polygonal shape inscribed in the cross sectional shape is 10 μm to 100 μm. One of the matrix part A and the columnar part B is of a nonuniform phase including a matrix region a and a plurality of columnar regions b in which the diameter and major axis length of a cross sectional shape in a plane parallel to the surface, the length of longest within the cross sectional shape or the length of longest in a polygonal shape inscribed in the cross sectional shape is 0.5 μm to 20 μm, and the other is of a uniform phase including only the matrix region a, the matrix region a and the columnar region b differing in absolute refractive index, the columnar region b extending from one surface toward the other surface.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an anisotropic optical film.

  A member having light diffusibility (light diffusing member) is used in a display device in addition to a lighting fixture and a building material. Examples of the display device include a liquid crystal display device (LCD), an organic electroluminescence element (organic EL), a so-called electronic paper of a microcapsule type, and the like. As a light diffusion expression mechanism of the light diffusion member, there is a mechanism by scattering (internal scattering) due to a difference in refractive index between the matrix resin and the fine structure formed therein.

For example, Patent Document 1 discloses an invention in which a single-layer polygonal light diffusion film having a lattice-like structure having a relatively high refractive index in a region having a relatively low refractive index diffuses incident light into a polygonal light. Has been proposed.
Patent Document 2 proposes a light diffusing film having a predetermined internal structure composed of a plurality of plate-like regions having different refractive indexes inside the film and capable of diffusing incident light into a polygonal shape. Has been.
In Patent Document 3, a portion having a different refractive index is distributed in an irregular shape / thickness inside the film, thereby forming a shading pattern having a high and low refractive index. There has been proposed a light scattering film having a structure distributed in a layered manner inclined with respect to the thickness direction of the film.

Japanese Patent Laid-Open No. 2006-48290 JP 2013-117703 A JP 2000-171619 A

  The light diffusing films of Patent Documents 1 to 3 are all intended for light diffusion utilizing the difference in refractive index between the matrix resin and the fine structure formed therein, and have sufficient light diffusibility. There is a problem that the ability to transmit light linearly from the light source provided on the back of the light toward the front observer is low. In other words, the entire screen of the display device has a uniform brightness, but the brightness (front brightness) when the display device is viewed from the front is low, and only a dark image can be obtained, or the contrast of the image is low. there were.

  In addition, when the light diffusing film of Patent Documents 1 to 3 is used for a head mounted display used in virtual reality (VR) technology, a screen using a black matrix of a color filter used in a display device such as a liquid crystal panel. Due to the door effect, the immersive feeling of the head mounted display cannot be obtained, and there is a possibility that the effect sufficient as the VR technology cannot be obtained. The screen door effect is a phenomenon in which image roughness or the like occurs due to the black matrix being visually recognized because the display device is provided close to the user's eyes.

  Furthermore, when the light diffusing films of Patent Documents 1 to 3 are used in a reflective display, the reflection luminance characteristics are excellent, but the contrast tends to be lowered. Since there is no light source when there is no external light, the reflective display is often used as a transflective display in combination with a backlight as necessary. When the light diffusing film of Patent Documents 1 to 3 is used for such a display, although the reflection luminance characteristic is excellent, the transmission characteristic is hindered, and in addition to the decrease in contrast, there is a problem of image quality deterioration due to the decrease in transmittance. there were.

  The present invention has been made in view of the above points, and the object of the present invention is to obtain high front luminance and high contrast of a display device. When used in a head mounted display, the luminance and contrast of the display device are obtained. An anisotropic optical film that can eliminate the screen door effect while suppressing a decrease and can improve brightness and contrast when used in a reflective or transflective display is provided. It is to be.

  The present inventors have intensively studied and found that the above problems can be solved by an anisotropic optical film having a specific structure, and have completed the present invention. That is, the present invention is as follows.

That is,
The present invention (1)
An anisotropic optical film in which the diffusivity of light emitted from the other surface changes depending on the incident angle of light incident from one surface,
The anisotropic optical film has a matrix portion A and a cross-sectional shape in a plane extending from one surface of the anisotropic optical film to the other surface and parallel to the plane direction of the anisotropic optical film. A columnar portion B having a diameter, a major axis length, a longest length in a cross-sectional shape, or a longest length in a polygonal shape inscribed in the cross-sectional shape of 10 μm to 100 μm,
Either one of the matrix part A or the columnar part B is a matrix region a and a diameter of a cross-sectional shape in a plane parallel to the surface of the anisotropic optical film, a long axis length, the longest length in the cross-sectional shape, Or, the maximum value of the longest length in the polygonal shape inscribed in the cross-sectional shape is a non-homogeneous phase including a plurality of columnar regions b of 0.5 μm to 20 μm, and the other is only the matrix region a A homogeneous phase comprising
The matrix region a and the plurality of columnar regions b have different absolute refractive indexes,
The plurality of columnar regions b are anisotropic optical films characterized by extending from one surface of the anisotropic optical film toward the other surface.
The present invention (2)
The anisotropic optical film according to the invention (1), wherein the matrix part A is a non-homogeneous phase and the columnar part B is a homogeneous phase.
The present invention (3)
The anisotropic optical film of the invention (1) or (2), wherein the columnar part B is inclined by 0 ° to 70 ° with respect to the normal direction of the surface of the anisotropic optical film. It is.
The present invention (4)
The columnar part B has a rectangular cross-sectional shape in a plane parallel to the anisotropic optical film surface, and the ratio of the length of the short side of the rectangular shape to the long side is 1: 1 to 1. The anisotropic optical film according to any one of the inventions (1) to (3), wherein:
The present invention (5)
The anisotropic aspects of the inventions (1) to (4), wherein the matrix part A and the columnar part B are formed in a lattice shape, as observed from the normal direction of the anisotropic optical film surface. Optical film.
The present invention (6)
The columnar part B has a circular or elliptical cross-sectional shape in a plane parallel to the anisotropic optical film surface, and the ratio of the length between the shortest diameter and the longest diameter of the circular or elliptical shape is 1: 1 to 1:20. The anisotropic optical film according to any one of the inventions (1) to (3).
The present invention (7)
The anisotropic optical film according to any one of the inventions (1) to (6), wherein the columnar region b is inclined by 0 ° to 70 ° with respect to the normal direction of the surface of the anisotropic optical film. It is.
The present invention (8)
The plurality of columnar regions b have a circular or elliptical cross-sectional shape in a plane parallel to the anisotropic optical film surface, and the length of the shortest diameter and the longest diameter of the circular or elliptical shape. Ratio is 1: 1-1: 20, It is an anisotropic optical film as described in said invention (1)-(7) characterized by the above-mentioned.
The present invention (9)
The plurality of columnar regions b observed from the normal direction of the anisotropic optical film surface are formed in a circular or elliptical shape, and the shortest diameter of the circular or elliptical shape and the length of the longest diameter The anisotropic optical film according to any one of the inventions (1) to (7), wherein the ratio is more than 1:20.
The present invention (10)
The inclination angle of the columnar part B with respect to the normal direction of the anisotropic optical film surface and the inclination angle of the columnar region b with respect to the normal direction of the anisotropic optical film surface are substantially the same. An anisotropic optical film according to any one of the inventions (3) to (9).

It is explanatory drawing which showed the incident angle dependence of the anisotropic optical film which concerns on this invention. It is the surface photograph observed from the normal line direction of the anisotropic optical film which concerns on this invention, and the cross-sectional photograph in the plane orthogonal to the normal line direction of an anisotropic optical film. It is a figure which shows the structural example of the matrix part A and the columnar part B seen from the normal line direction of the anisotropic optical film which concerns on this invention. It is a three-dimensional polar coordinate display for demonstrating the scattering center axis | shaft in an anisotropic optical film. It is a schematic diagram which shows the example of the anisotropic optical film which concerns on this invention. It is a graph for demonstrating the diffusion area | region and non-diffusion area | region in an anisotropic optical film. It is a schematic diagram which shows the incident light angle dependence measuring method of an anisotropic optical film. It is an optical profile of an anisotropic optical film having a structure having a columnar region with an aspect ratio of 2 or more and less than 20. It is a schematic diagram explaining the effect of the anisotropic optical film of this invention. It is a schematic diagram explaining the manufacturing method of the anisotropic optical film of this invention. It is a schematic diagram which shows the example of the mask pattern of the anisotropic optical film of this invention. It is an optical profile of the anisotropic optical film of Examples 1, 2, and 10. 4 is an optical profile of an anisotropic optical film of Comparative Examples 1 and 2 and an isotropic optical film of Comparative Example 4.

<Definition of main terms>

“Matrix part A” and “columnar part B” indicate structural units from the macro viewpoint of the anisotropic optical film according to the present invention. One of “matrix part A” and “columnar part B” is a non-homogeneous phase, and the other is a homogeneous phase.
The “matrix region a” and the “columnar region b” are structural units in a micro viewpoint included in the “matrix portion A” or “columnar portion B” which is the non-homogeneous phase.
“Linear transmittance” generally relates to the linear transmittance of light incident on an anisotropic optical film or a non-homogeneous phase, and transmission in the same linear direction as the incident direction when incident from a certain incident light angle. This is the ratio between the amount of light and the amount of incident light, and is expressed by the following equation.
Linear transmittance (%) = (Linear transmitted light amount / incident light amount) × 100

  The “scattering central axis” is an incident light angle of light having a substantially linear symmetry with respect to the incident light angle when the incident light angle to the anisotropic optical film or the non-homogeneous phase is changed. Means matching direction. “Substantially symmetrical” means that when the scattering center axis is inclined with respect to the normal direction of the film, the optical characteristics (“optical profile” described later) are not strictly symmetrical. Because. The scattering central axis is confirmed by observing the inclination of the cross section of the anisotropic optical film with an optical microscope or by observing the projected shape of light through the anisotropic optical film while changing the incident light angle. be able to.

  The “scattering center angle” is the inclination of the scattering center axis with respect to the normal direction of the anisotropic optical film or the film of the non-uniform phase, and when the normal direction of the anisotropic optical film is 0 ° Is the angle.

  In the present invention, both “scattering” and “diffusion” are used without distinction, and both indicate the same meaning. Furthermore, the meaning of “photopolymerization” and “photocuring” means that a photopolymerizable compound undergoes a polymerization reaction with light, and both are used synonymously.

  In the present specification, when “normal direction” is described without any notice, it means “normal direction of anisotropic optical film surface”.

<< anisotropic optical film >>
In the anisotropic optical film according to the present invention, the linear transmittance changes depending on the incident angle of incident light. That is, incident light in a predetermined angle range is transmitted while maintaining linearity, and incident light in other angle ranges does not transmit all components linearly but partially diffuses (for example, FIG. 1). ). FIG. 1 is an example showing diffusivity when the incident angle is 20 ° to 50 °, and shows that the diffusibility is not shown at other angles but linear transmittance is shown. That is, at 0 ° smaller than 20 ° and 65 ° larger than 50 °, diffusion does not occur and only linear transmission occurs.

  The anisotropic optical film according to the present invention includes only the non-uniform phase by including the non-homogeneous phase having the optical anisotropy and the homogeneous phase not having the optical anisotropy. Compared to an anisotropic optical film, it has a characteristic that it can give good optical properties. Specifically, it is possible to achieve both high diffusibility and high permeability.

1. Structure of Anisotropic Optical Film The thickness of the anisotropic optical film according to the present invention is not particularly limited, but is preferably 5 μm to 200 μm, and more preferably 10 to 100 μm, for example. When the thickness exceeds 200 μm, not only the material cost is increased, but also the cost for UV irradiation is increased, so that the cost is increased. Due to the increase in diffusibility in the thickness direction of the anisotropic optical film, image blur and contrast are increased. Decline is likely to occur. Further, when the thickness is less than 5 μm, it may be difficult to achieve sufficient light diffusibility and light condensing performance.

  The anisotropic optical film according to the present invention can be laminated with other layers and films. Here, the other layers are not particularly limited, and examples thereof include anisotropic optical films, pressure-sensitive adhesive layers, release film polarizing films, and retardation films having different optical characteristics. The number of layers to be stacked is not particularly limited. The anisotropic optical film may be laminated on a transparent hard substrate such as a glass substrate.

  The anisotropic optical film according to the present invention includes a matrix portion A and a columnar portion B extending from one surface of the anisotropic optical film toward the other surface. The columnar part B may penetrate from one surface of the anisotropic optical film to the other surface, or may not reach one surface or both surfaces. In FIG. 2, a surface photograph {FIG. 2 (a)} observed from the normal direction of the anisotropic optical film 1 by an optical microscope, and a cross-sectional photograph in a plane perpendicular to the surface of the anisotropic optical film 1 { FIG. 2 (b)} is shown. FIG. 2 shows an anisotropic optical film having a lattice arrangement in which the matrix portion A (10) is a non-uniform phase and the columnar portion B (20) is a uniform phase. In FIG. 2B, the columnar portion B (20) penetrates from one surface 2 to the other surface 3 of the anisotropic optical film.

  The cross-sectional shape in the plane parallel to the plane direction of the anisotropic optical film of the columnar part B is not particularly limited, and can be, for example, a circular shape, an elliptical shape, or a polygonal shape. The longest length connecting the two vertices in the circular shape, the elliptical long axis, and the polygonal polygon of the cross-sectional shape is 10 μm to 100 μm. In other cross-sectional shapes, a polygon inscribed in each shape is assumed, and the longest length connecting two vertices in the polygon is 10 μm to 100 μm.

  In the present specification, the cross-sectional shape in the cross-sectional shape of the columnar part B is the circular diameter, the long axis of the elliptical shape, the longest length connecting two vertices in the polygonal polygon, and the other cross-sectional shapes. An inscribed polygon is assumed, and the longest length connecting two vertices in the polygon may be expressed as the longest diameter LB. Similarly, the diameter of a circle (which is the same as the longest diameter in the case of a circle), the short axis of an ellipse, the shortest length connecting two vertices in a polygon on the polygon, and other shapes In the cross-sectional shape, a polygon inscribed in the cross-sectional shape is assumed, and the shortest length connecting two vertices in the polygon may be expressed as the shortest diameter SB.

  The cross-sectional shape of the columnar part B is preferably a circular shape, an elliptical shape, or a square shape in order to make the optical characteristics uniform over the entire surface of the anisotropic optical film and easy to manufacture, and its shortest diameter SB The ratio of the longest diameter LB is more preferably 1: 1 to 1:20. If it is circular or square, it is possible to keep the visibility unchanged from both the vertical and horizontal directions of the anisotropic optical film, but you want to make a difference in the vertical and horizontal diffusivity. For example, by increasing the ratio of the shortest diameter SB to the longest diameter LB, such as an elliptical shape, priority can be given to diffusibility in either direction. However, if the ratio is larger than 1:20, interference is likely to occur, and thus unevenness in visibility is not preferable.

  The longest diameter LB and the shortest diameter SB of the columnar part B according to the present invention are obtained by observing the surface of the anomalous optical film with an optical microscope and measuring the longest diameter and the shortest diameter of 20 arbitrarily selected columnar parts B. And it can be set as the average value of these.

  The columnar part B can be inclined by 0 ° to 70 ° with respect to the normal direction. By doing in this way, the front brightness | luminance with respect to the light from the film front can be adjusted, for example. The example of FIG. 2 shows a case where the inclination angle is 0 °. In this case, the luminance with respect to the front surface of the display unit of the display device can be maximized.

  The shape, position, distribution density, and number of distributions of the matrix part A and the columnar part B are not particularly limited, and at least one columnar part B only needs to exist as the matrix part A. For example, when used in a display device, a structure such as a repetitive array such as a lattice or a random array is preferable when observed from the normal direction in order to give uniform optical characteristics to the entire display unit of the display device. (Figure 3). Here, for example, the lattice shape is a 45 ° lattice {FIG. 3 (a)}, a 60 ° lattice {FIG. 3 (b)}, a square lattice {FIG. 3 (c)}, as viewed from the normal direction. Etc. Further, as a repeating structure, a dot-like structure such as a checkered pattern as shown in FIGS. 3D and 3E can be given, and as a random arrangement, FIG. 3F can be mentioned.

  In the present invention, the matrix portion A can exist as the matrix portion A (10) is completely divided by the columnar portion B (20) as shown in FIG. In this case, both the matrix part A (10) and the columnar part B (20) have a columnar structure, but one can be arbitrarily set as the matrix part A.

  The matrix part A and the columnar part B preferably have a lattice-like repetitive structure and more preferably have a square (particularly square) grid pattern for the effect of eliminating the black matrix of the display device. This is because the black matrix of the display device has a lattice-like repetitive structure and is usually a square lattice.

  Either one of the matrix part A or the columnar part B (hereinafter referred to as the matrix part A or the like) has a cross-sectional diameter or side length in a plane parallel to the planar direction of the matrix region a and the anisotropic optical film. Is a non-homogeneous phase including a plurality of columnar regions b of 5 μm or less, and the other is a homogeneous phase including only the matrix region a.

  The matrix portion A which is a non-homogeneous phase according to the present invention has anisotropic optical characteristics in which the diffusibility of light emitted from the other surface changes depending on the incident angle of light incident from one surface. .

  In the non-homogeneous phase according to the present invention, when there are a plurality of matrix portions A or columnar portions B, all the non-homogeneous phases may have the same optical characteristics, or a plurality of optical characteristics. The non-homogeneous phase which it has may be mixed. The number of non-homogeneous phases having a plurality of optical characteristics is not particularly limited. However, when the number increases, it takes time and effort for production, and therefore three or less phases are preferable, and a single phase is more preferable.

1-1. Non-homogeneous phase The non-homogeneous phase according to the present invention will be described below. As described above, the non-homogeneous phase according to the present invention has an anisotropic optical characteristic in which the diffusivity of light emitted from the other surface changes depending on the incident angle of the light incident from one surface. .

  The non-homogeneous phase includes a matrix region a and a plurality of columnar regions b having a cross-sectional diameter or side length of 20 μm or less in a plane parallel to the plane direction of the anisotropic optical film. The anisotropic optical characteristics are exhibited by the inclination of the columnar region b from the normal direction and the asymmetry of the cross-sectional shape.

  The matrix region a and the columnar region b have different absolute refractive indexes and are formed by phase separation of the same composition. Here, the difference in absolute refractive index is sufficient if there is a difference in absolute refractive index. For example, the difference in absolute refractive index may be 0.001 or more.

  The columnar region b extends from one surface of the matrix portion A or the like to the other surface, and can have one or more orientation directions. That is, the columnar region b can be inclined with respect to the normal direction.

The non-homogeneous phase according to the present invention can have a scattering central axis.
The extending direction (orientation direction) P of the columnar region b can be formed so as to be parallel to the scattering center axis, and is appropriately determined so that the non-uniform phase has desired linear transmittance and diffusibility. it can. Note that the fact that the scattering center axis and the alignment direction of the columnar region b are parallel only needs to satisfy the law of refractive index (Snell's law), and does not need to be strictly parallel.

  According to Snell's law, when light is incident on the interface of a medium having a refractive index n1 from a medium having a refractive index n1, a relationship of n1sin θ1 = n2sin θ2 is established between the incident light angle θ1 and the refractive angle θ2. It is. For example, when n1 = 1 (air) and n2 = 1.51 (non-uniform phase), when the incident light angle is 30 °, the orientation direction (refractive angle) of the columnar region b is about 19 °. Thus, even if the incident light angle and the refraction angle are different, if the Snell's law is satisfied, it is included in the parallel concept in the present invention.

  Further, when the normal direction is 0 ° and the scattering central axis is inclined, the columnar region b can be formed inclined. The angle of inclination of the scattering central axis (the axial direction of the columnar region b) is not particularly limited, and is, for example, −70 ° to + 70 °. In the range exceeding -70 ° to + 70 °, it is necessary to irradiate light from a deep inclination with respect to the composition containing the photopolymerizable compound provided in the form of a sheet in the manufacturing process described later, and the absorption efficiency of irradiation light is Since it is bad and disadvantageous in manufacture, it is not preferable.

  The scattering center axis angle is positive or negative with respect to a plane passing through both the predetermined symmetry axis in the plane direction of the anisotropic optical film and the normal line of the anisotropic optical film. The case of being inclined is defined as +, and the case of being inclined to the other side is defined as-.

  The polar angle θ (−90 ° <θ <90 °) formed by the normal line of the anisotropic optical film (z axis shown in FIG. 4) and the columnar region b is defined as the scattering center axis angle in the present invention. The angle in the axial direction of the columnar region b can be adjusted to a desired angle by changing the direction of light rays applied to the composition containing the sheet-like photopolymerizable compound when these are produced.

  When a plurality of scattering center axes are included in the non-homogeneous phase according to the present invention, the plurality of orientation directions of the columnar region b can be parallel to each of the plurality of scattering center axes.

  The columnar region b extends from one surface of the matrix portion A or the columnar portion B toward the other surface.

  The length of the columnar region b is not particularly limited, and may extend from one surface of the non-homogeneous phase to the other surface, or may not reach one surface or both surfaces.

  The cross-sectional shape of the columnar region b in a plane parallel to the plane direction of the anisotropic optical film is not particularly limited, and can be, for example, a circular shape, an elliptical shape, or a polygonal shape. In the cross-sectional shape, the longest length connecting two vertices in the polygonal diameter, the long axis of the elliptical shape, and the polygon on the polygonal shape, or in the cross-sectional shapes of other shapes, Assuming a square shape, the longest length connecting two vertices in the polygon is 0.5 μm to 20 μm.

  In this specification, in the cross-sectional shape of the columnar region b, the cross-section in the circular diameter, the long axis of the elliptical shape, the longest length connecting two vertices in the polygon on the polygon, and the other cross-sectional shapes Assuming a polygon inscribed in the shape, the longest length connecting two vertices in the polygon may be expressed as the longest diameter Lb. Similarly, the diameter of a circle (which is the same as the longest diameter in the case of a circle), the short axis of an ellipse, the shortest length connecting two vertices in a polygon on the polygon, and other shapes In the cross-sectional shape, a polygon inscribed in the cross-sectional shape is assumed, and the shortest length connecting two vertices in the polygon may be expressed as the shortest diameter Sb.

  The cross-sectional shape is preferably a circular shape, an elliptical shape, or a square shape in order to make the optical characteristics uniform over the entire surface of the anisotropic optical film and easy to manufacture, and has a shortest diameter Sb and a longest diameter Lb. The ratio is more preferably 1: 1 to 1:20. If it is circular or square, it is possible to keep the visibility unchanged from both the vertical and horizontal directions of the anisotropic optical film, but you want to make a difference in the vertical and horizontal diffusivity. For example, by increasing the ratio of the shortest diameter Sb to the longest diameter Lb, such as an elliptical shape, priority can be given to the diffusibility in either direction. However, if the ratio is larger than 1:20, interference is likely to occur, and thus unevenness in visibility is not preferable.

  The longest diameter Lb and the shortest diameter Sb of the columnar region b according to the present invention are obtained by observing the surface of the abnormal optical film with an optical microscope and measuring the longest diameter and the shortest diameter of 20 arbitrarily selected columnar regions b. And it can be set as the average value of these. Hereinafter, the average value of the longest diameter is referred to as average long diameter MLb, and the average value of the shortest diameter is referred to as average short diameter MSb.

  Further, the ratio of the average major axis MLb to the average minor axis MSb of the columnar region b according to the present invention (average minor axis MSb / average major axis MLb, hereinafter referred to as aspect ratio), that is, the aspect ratio is not particularly limited. It is preferably 1 or more and 20 or less in order to prevent abrupt change or glare. FIG. 5A shows a non-homogeneous phase with an aspect ratio of less than 2, and FIG. 5B shows a non-homogeneous phase with an aspect ratio of 2 or more. Reference numeral 60 in FIGS. 5A and 5B denotes a columnar region b.

  When the aspect ratio is 1 or more and less than 2, when light parallel to the axial direction of the columnar region b is irradiated, the transmitted light diffuses isotropically {see the shape of the transmitted light in FIG. 5A }. On the other hand, when the aspect ratio is 2 or more, similarly, when light parallel to the axial direction is irradiated, the light diffuses with anisotropy corresponding to the aspect ratio {the shape of transmitted light in FIG. reference}.

  The anisotropic optical film according to the present invention may include a plurality of columnar regions b having one aspect ratio, or may include a plurality of columnar regions b having different aspect ratios.

1-1-1. Optical characteristics of non-homogeneous phase Here, optical characteristics when a film is produced including only a non-homogeneous phase having a single optical characteristic will be described, and the optical characteristics of the non-uniform phase of the present invention will be described.
As shown in FIG. 6, the non-homogeneous phase (or anisotropic optical film) has light diffusivity that depends on the incident light angle, in which the linear transmittance changes depending on the incident light angle. Here, as shown in FIG. 6, the curve showing the light diffusion dependency on the incident light angle is hereinafter referred to as an “optical profile”.

  In the optical profile, as shown in FIG. 7, a non-homogeneous phase (or anisotropic optical film) is disposed between the light source 70 and the detector 80. In the present embodiment, the incident light angle is 0 ° when the irradiation light L from the light source 70 is incident from the normal direction of the non-uniform phase (or anisotropic optical film). Further, the non-homogeneous phase (or anisotropic optical film) is arranged so that it can be arbitrarily rotated around the straight line V, and the light source 70 and the detector 80 are fixed. That is, according to this method, a sample {non-homogeneous phase (or anisotropic optical film)} is arranged between the light source 70 and the detector 80, and the angle is changed with the straight line V of the sample surface as the central axis. On the other hand, the linear transmittance is obtained by measuring the amount of linearly transmitted light that passes straight through the sample and enters the detector 80, thereby obtaining an optical profile.

  The optical profile does not directly express the light diffusivity, but if it is interpreted that the diffuse transmittance increases due to the decrease of the linear transmittance, the optical profile generally shows the light diffusibility. It can be said that. In an ordinary isotropic light diffusing film, a peak-shaped optical profile having a peak near 0 ° is shown. In the non-homogeneous phase (or anisotropic optical film), the axial direction of the columnar region b, that is, Compared to the linear transmittance in the case of incidence in the scattering central axis direction (incident light angle in this direction is 0 °), the linear transmittance once reaches a minimum value at an incident light angle of −20 ° to + 20 °. As the incident light angle (the absolute value thereof) increases, the linear transmittance increases, and the linear transmittance becomes a maximum value at the incident light angles of + 25 ° to + 60 ° and −60 ° to −25 °. The optical profile of is shown.

  Thus, in the non-homogeneous phase (or anisotropic optical film), the incident light is strongly diffused in the incident light angle range of −20 ° to + 20 ° close to the scattering central axis direction, but the incident light beyond that. In the angle range, the diffusion is weakened and the linear transmittance is increased. Hereinafter, the angle range of two incident light angles with respect to the linear transmittance that is an intermediate value between the maximum linear transmittance and the minimum linear transmittance is referred to as a diffusion region (the width of the diffusion region is referred to as a “diffusion width”), and other incident light is incident. The light angle range is referred to as a non-diffusion region (transmission region).

  Here, with reference to FIG. 8, the diffusion region and the non-diffusion region will be described by taking a non-uniform phase having a structure having a columnar region b having an aspect ratio of 2 or more and less than 20 as an example. FIG. 8 shows an optical profile of a non-homogeneous phase having a structure having a columnar region b having an aspect ratio of 2 or more and less than 20, but the maximum linear transmittance (example of FIG. 8) is shown in FIG. In this case, the linear transmittance is an intermediate value between the linear transmittance (about 78%) and the minimum linear transmittance (in the example of FIG. 8, the linear transmittance is about 6%). 42%), the incident light angle range between the two incident light angles (inside the two incident light angles at the positions of the two black spots on the optical profile shown in FIG. 8) is the diffusion region, and the others (in FIG. 8) The incident light angle range (outside the two incident light angles at the positions of the two black spots on the optical profile shown) is the non-diffusing region.

  In the anisotropic optical film having the above structure, as can be seen from the state of the transmitted light in FIG. 5B, the transmitted light has a substantially needle shape, and the direction of the major axis of the columnar region b and the aspect ratio. The light diffusivity is greatly different. That is, in the non-homogeneous phase of the structure, diffusion has anisotropy. Specifically, in the example shown in FIG. 5B, diffusion is widened in the minor axis direction of the columnar region b, but diffusion is narrowed in the major axis direction. Further, as shown by the broken line in FIG. 6, when the incident light angle is changed, the change in light diffusibility (particularly, the optical profile near the boundary between the non-diffusing region and the diffusing region) is extremely steep, so Although there is a possibility that a slight change or glare may occur, there is an effect that the linear transmittance in the non-diffusion region is high and display characteristics such as luminance and contrast can be improved.

  On the other hand, in the non-homogeneous phase having a columnar region b having an aspect ratio of less than 2, the transmitted light has a substantially circular shape, as can be seen from the state of the transmitted light in FIG. Shows light diffusivity without bias. That is, the diffusion of the non-homogeneous phase of this structure is isotropic. Further, as shown by the solid line in FIG. 6, since the change in light diffusivity (particularly, the optical profile near the boundary between the non-diffusing region and the diffusing region) is relatively gradual even when the incident light angle is changed, It has the effect of preventing sudden changes and glare. However, in the non-uniform phase of this structure, as shown in FIG. 6, since the linear transmittance in the non-diffusion region is low, the display characteristics (luminance, contrast, etc.) tend to be slightly lowered.

1-2. Homogeneous phase One of the matrix part A or the columnar part B according to the present invention is a homogeneous phase, and the other is a non-homogeneous phase.

  The homogeneous phase is a phase in which not only the components contained in the homogeneous phase are uniform, but also optical characteristics such as refractive index are uniform. Therefore, even when the homogeneous phase is phase-separated, it may be optically uniform. For example, even if it has micro-phase separation of sea-island structure, it is optically uniform, that is, when there is a sea part and island part of sea-island structure, there is no difference in their refractive index etc. Use a homogeneous phase.

  In the uniform phase, the light emitted from the other surface exhibits linear transparency regardless of the incident angle of the light incident from the surface of one uniform phase. That is, the light incident on the uniform phase does not diffuse except for slightly diffusing or reflecting on the surface of the uniform phase. Here, after the incident light is slightly diffused or reflected, the linear transmittance when the light is emitted as the linear transmitted light can be 90% or more.

  In the anisotropic optical film, a plurality of uniform phases can be formed, but each formed uniform phase may have the same optical characteristics (such as a refractive index), It may have different optical properties.

2. Characteristics of anisotropic optical film 2-1. Scattering central axis of anisotropic optical film The anisotropic optical film according to the present invention can have at least one scattering central axis. The scattering center axis angle is not particularly limited, and is, for example, −70 ° to + 70 °. In the range exceeding -70 ° to + 70 °, it is necessary to irradiate light from a deep inclination with respect to the composition containing the photopolymerizable compound provided in the form of a sheet in the manufacturing process described later, and the absorption efficiency of irradiation light is Since it is bad and disadvantageous in manufacture, it is not preferable.

2-2. Haze value of anisotropic optical film The haze value of the anisotropic optical film according to the present invention is not particularly limited, but is preferably 5% to 90%, more preferably 30% to 80%, and more preferably 50% to 70%. % Is more preferable.

  The method for measuring the haze value of the anisotropic optical film is not particularly limited, and can be measured by a known method. For example, it can be measured according to JIS K7166-1: 2000 “Plastics—How to determine haze of transparent material”.

2-3. Linear transmittance of anisotropic optical film The linear transmittance of light incident from the normal direction of the anisotropic optical film of the present invention is not particularly limited, but is preferably 1 to 50%, for example, and 5 to 45%. More preferably, 10% to 40% is more preferable. By setting it as this range, the effect of reducing or eliminating the visibility of the black matrix can be enhanced.

2-4. Brightness improvement effect of anisotropic optical film (diffusion behavior)
Here, the effect of the anisotropic optical film described above will be described in detail with reference to FIG. FIG. 9 is a schematic diagram showing how incident light incident on the anisotropic optical film according to the present invention is diffused by the anisotropic optical film, and a graph showing the front luminance with respect to the outgoing angle of the transmitted light. It is. FIGS. 9A and 9B are anisotropic optical films having the matrix part A and the columnar part B shown in FIG. 2 and having the matrix part A as a non-homogeneous phase. It is an anisotropic optical film formed with an average major axis MLb of the included columnar region b of 5 μm and an average minor axis MSb of 5 μm (that is, an aspect ratio of 1). FIG. 9A is a model diagram when the inclination of the columnar region b is 0 ° (inclination with respect to the normal direction), and FIG. 9B is a model diagram when the columnar region b is inclined 45 °. It is. The solid line in the graph represents the luminance behavior exhibited by the above-described anisotropic optical film according to the present invention, and the broken line represents the luminance behavior exhibited by the anisotropic optical film prepared using only the non-uniform phase described above.

  In FIGS. 9A and 9B, the anisotropic optical film according to the present invention indicated by the solid line can have higher brightness (higher linear transmittance). This is because the anisotropic optical film of the present invention includes a uniform phase having a very high linear transmittance, so that the linear transmittance can be improved. It is characterized in that both the linear transmittance can be increased.

  On the other hand, an anisotropic optical film consisting only of a non-homogeneous phase has a high diffusivity as shown by a broken line, but it is difficult to increase the brightness of transmitted light. The maximum linear transmittance or the minimum linear transmittance described above is difficult. Only one of them can be expensive. This is because when the maximum linear transmittance is increased, the diffusibility is reduced, so the minimum linear transmittance is decreased. When the minimum linear transmittance is increased, the diffusivity needs to be increased. It is because it falls.

  That is, in the anisotropic optical film according to the present invention, it is possible to adjust the diffusibility and the linear transmittance with a uniform phase and a non-homogeneous phase. By adjusting, there is an effect that the linear permeability can be adjusted as another variable.

3. Method for Producing Anisotropic Optical Film (Nonhomogeneous Phase and Uniform Phase) The method for producing an anisotropic optical film of the present invention can be produced by irradiating a photocurable composition layer with light such as UV. . Hereinafter, the raw material of the anisotropic light diffusion layer will be described first, and then the manufacturing process will be described. In the following, anisotropic optics including a non-homogeneous phase having one type of optical characteristics (that is, only one type of columnar region b has a shape, inclination, size, etc.), which is a preferred example, is mainly described below. The production of the film will be described, and other aspects will be supplemented as necessary.

3-1. Raw Material for Anisotropic Optical Film The raw material for the anisotropic optical film will be described in the order of (1) photopolymerizable compound, (2) photoinitiator, (3) blending amount, and other optional components.

3-1-1. Photopolymerizable compound The photopolymerizable compound which is a material for forming the anisotropic optical film according to the present invention is a light selected from a macromonomer, a polymer, an oligomer, and a monomer having a radical polymerizable or cationic polymerizable functional group. It is a material composed of a polymerizable compound and a photoinitiator, and polymerized and cured by irradiation with ultraviolet rays and / or visible rays. Here, even if the material forming the non-homogeneous phase contained in the anisotropic optical film is one kind, a difference in refractive index is caused by the difference in density. This is because a portion having a high UV irradiation intensity has a fast curing speed, and thus the polymerized / cured material moves around the cured region, resulting in formation of a region having a higher refractive index and a region having a lower refractive index. . In addition, (meth) acrylate means that either acrylate or methacrylate may be sufficient.

  The radically polymerizable compound mainly contains one or more unsaturated double bonds in the molecule, specifically, epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate, polybutadiene acrylate, silicone acrylate, etc. Acrylic oligomer called by the name of 2-ethylhexyl acrylate, isoamyl acrylate, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, isonorbornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate 2-acryloyloxyphthalic acid, dicyclopentenyl acrylate, triethylene glycol diacrylate Neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, EO adduct diacrylate of bisphenol A, trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ditrimethylol Examples thereof include acrylate monomers such as propanetetraacrylate and dipentaerythritol hexaacrylate. In addition, these compounds may be used alone or in combination. Similarly, methacrylate can also be used, but acrylate is generally preferable to methacrylate because of its higher photopolymerization rate.

  As the cationically polymerizable compound, a compound having at least one epoxy group, vinyl ether group or oxetane group in the molecule can be used. The compounds having an epoxy group include 2-ethylhexyl diglycol glycidyl ether, glycidyl ether of biphenyl, bisphenol A, hydrogenated bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetrachloro Diglycidyl ethers of bisphenols such as bisphenol A and tetrabromobisphenol A, polyglycidyl ethers of novolac resins such as phenol novolak, cresol novolak, brominated phenol novolak, orthocresol novolak, ethylene glycol, polyethylene glycol, polypropylene glycol, Butanediol, 1,6-hexanediol, neopentyl glycol, trimethyl Diglycidyl ethers of alkylene glycols such as propane adduct of 1,4-cyclohexanedimethanol, bisphenol A, PO adduct of bisphenol A, glycidyl ester of hexahydrophthalic acid, diglycidyl ester of dimer acid, etc. Examples thereof include glycidyl esters.

  Further, as the compound having an epoxy group, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) Cyclohexane-meta-dioxane, di (3,4-epoxycyclohexylmethyl) adipate, di (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4 ′ -Epoxy-6'-methylcyclohexanecarboxylate, methylene bis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylene bis (3,4-epoxy Cyclohexane Boxylate), lactone-modified 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, tetra (3,4-epoxycyclohexylmethyl) butanetetracarboxylate, di (3,4-epoxycyclohexylmethyl)- Examples thereof include, but are not limited to, alicyclic epoxy compounds such as 4,5-epoxytetrahydrophthalate.

  Examples of the compound having a vinyl ether group include diethylene glycol divinyl ether, triethylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, hydroxybutyl vinyl ether, ethyl vinyl ether, dodecyl vinyl ether, trimethylol propane tri Vinyl ether, propenyl ether propylene carbonate and the like can be mentioned, but are not limited thereto. Vinyl ether compounds are generally cationically polymerizable, but radical polymerization is also possible by combining with acrylates.

  As the compound having an oxetane group, 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 3-ethyl-3- (hydroxymethyl) -oxetane and the like can be used.

The above cationic polymerizable compounds may be used alone or in combination. The photopolymerizable compound is not limited to the above. In order to cause a sufficient difference in refractive index, fluorine atoms (F) may be introduced into the photopolymerizable compound in order to reduce the refractive index, and in order to increase the refractive index, Sulfur atoms (S), bromine atoms (Br), and various metal atoms may be introduced. Further, as disclosed in JP 2005-514487 A, ultrafine particles made of a metal oxide having a high refractive index such as titanium oxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), tin oxide (SnO _x ), etc. It is also effective to add functional ultrafine particles having a photopolymerizable functional group such as an acryl group, a methacryl group, and an epoxy group introduced to the surface to the photopolymerizable compound.

As the photopolymerizable compound according to the present invention, a photopolymerizable compound having a silicone skeleton is preferably used. A photopolymerizable compound having a silicone skeleton is oriented and polymerized and cured in accordance with its structure (mainly ether bond), and has a low refractive index region, a high refractive index region, or a low refractive index region and a high refractive index region. Form. By using a photopolymerizable compound having a silicone skeleton, the columnar region b can be easily inclined, and the light condensing property in the front direction is improved. The low refractive index region corresponds to one of the columnar region b and the matrix region a, and the other corresponds to the high refractive index region.

  In the low refractive index region, it is preferable that the silicone resin that is a cured product of the photopolymerizable compound having a silicone skeleton relatively increases. As a result, the scattering central axis can be more easily inclined, and thus the light condensing property in the front direction is improved. Since a silicone resin contains a larger amount of silica (Si) than a compound having no silicone skeleton, relative use of the silicone resin can be achieved by using an EDS (energy dispersive X-ray spectrometer) with this silica as an index. The correct amount.

  The photopolymerizable compound having a silicone skeleton is a monomer, oligomer, prepolymer or macromonomer having a radically polymerizable or cationically polymerizable functional group. Examples of the radical polymerizable functional group include an acryloyl group, a methacryloyl group, and an allyl group. Examples of the cationic polymerizable functional group include an epoxy group and an oxetane group. There are no particular restrictions on the type and number of these functional groups, but it is preferable to have a polyfunctional acryloyl group or methacryloyl group because the crosslink density increases and the difference in refractive index tends to occur as the number of functional groups increases. . Moreover, although the compound which has a silicone frame | skeleton may be inadequate in compatibility with another compound from the structure, in such a case, it can urethanize and can improve compatibility. In this embodiment, silicone, urethane, (meth) acrylate having an acryloyl group or a methacryloyl group at the terminal is preferably used.

  The weight average molecular weight (Mw) of the photopolymerizable compound having a silicone skeleton is preferably in the range of 500 to 50,000. More preferably, it is the range of 2,000-20,000. When the weight average molecular weight is in the above range, a sufficient photocuring reaction occurs, and the silicone resin present in each anisotropic light diffusion layer of the anisotropic optical film 100 is easily oriented. With the orientation of the silicone resin, the scattering central axis is easily inclined.

  Examples of the silicone skeleton include those represented by the following general formula (1). In the general formula (1), R1, R2, R3, R4, R5, and R6 are each independently a methyl group, an alkyl group, a fluoroalkyl group, a phenyl group, an epoxy group, an amino group, a carboxyl group, a polyether group, and acryloyl. And functional groups such as a methacryloyl group. Moreover, in general formula (1), it is preferable that n is an integer of 1-500.

  When a photopolymerizable compound having a silicone skeleton is blended with a compound not having a silicone skeleton to form a non-homogeneous phase, the low refractive index region and the high refractive index region are likely to be separated and formed with an anisotropic property. The degree is preferable because it is strong. As the compound having no silicone skeleton, a thermoplastic resin or a thermosetting resin can be used in addition to the photopolymerizable compound, and these can be used in combination. As the photopolymerizable compound, a polymer, oligomer, or monomer having a radical polymerizable or cationic polymerizable functional group can be used (however, it does not have a silicone skeleton). Examples of the thermoplastic resin include polyester, polyether, polyurethane, polyamide, polystyrene, polycarbonate, polyacetal, polyvinyl acetate, acrylic resin, and a copolymer or modified product thereof. In the case of using a thermoplastic resin, it is dissolved using a solvent in which the thermoplastic resin dissolves, and after application and drying, the photopolymerizable compound having a silicone skeleton is cured with ultraviolet rays to form an anisotropic light diffusion layer. Examples of the thermosetting resin include epoxy resins, phenol resins, melamine resins, urea resins, unsaturated polyesters, copolymers thereof, and modified products. In the case of using a thermosetting resin, the photopolymerizable compound having a silicone skeleton is cured with ultraviolet rays and then appropriately heated to cure the thermosetting resin and form the anisotropic light diffusion layer. The most preferable compound that does not have a silicone skeleton is a photopolymerizable compound, which easily separates a low refractive index region and a high refractive index region, and does not require a solvent and a drying process when a thermoplastic resin is used. It is excellent in productivity, such as being no thermal curing process like a thermosetting resin.

3-1-2. Photoinitiators Photoinitiators that can polymerize radically polymerizable compounds include benzophenone, benzyl, Michler's ketone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2 , 2-diethoxyacetophenone, benzyldimethyl ketal, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl Ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1- Propan-1-one, bis (Cyclopentadienyl) -bis (2,6-difluoro-3- (pyr-1-yl) titanium, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2 , 4,6-trimethylbenzoyldiphenylphosphine oxide, etc. These compounds may be used alone or in combination.

  The photoinitiator of the cationic polymerizable compound is a compound capable of generating an acid by light irradiation and polymerizing the above cationic polymerizable compound with the generated acid. Generally, an onium salt, a metallocene is used. Complexes are preferably used. As the onium salt, a diazonium salt, a sulfonium salt, an iodonium salt, a phosphonium salt, a selenium salt, or the like is used, and an anion such as BF4-, PF6-, AsF6-, or SbF6- is used as these counter ions. Specific examples include 4-chlorobenzenediazonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, (4-phenylthiophenyl) diphenylsulfonium hexafluoroantimonate, (4-phenylthiophenyl) diphenyl. Sulfonium hexafluorophosphate, bis [4- (diphenylsulfonio) phenyl] sulfide-bis-hexafluoroantimonate, bis [4- (diphenylsulfonio) phenyl] sulfide-bis-hexafluorophosphate, (4-methoxyphenyl) Diphenylsulfonium hexafluoroantimonate, (4-methoxyphenyl) phenyliodonium hexafluoroantimonate Bis (4-t-butylphenyl) iodonium hexafluorophosphate, benzyltriphenylphosphonium hexafluoroantimonate, triphenyl selenium hexafluorophosphate, (η5-isopropylbenzene) (η5-cyclopentadienyl) iron (II) hexa Although fluorophosphate etc. are mentioned, it is not limited to these. In addition, these compounds may be used alone or in combination.

3-1-3. Compounding amount and other components The photoinitiator according to the present invention is 0.01 to 10 parts by mass, preferably 0.1 to 7 parts by mass, more preferably 0.1 to 100 parts by mass of the photopolymerizable compound. About 5 parts by mass is blended. This is because when less than 0.01 parts by mass, the photocurability is lowered, and when more than 10 parts by mass is incorporated, only the surface is cured and the internal curability is lowered, coloring, columnar structure This is because it inhibits the formation of. These photoinitiators are usually used by directly dissolving powder in a photopolymerizable compound, but if the solubility is poor, a photoinitiator dissolved beforehand in a very small amount of solvent at a high concentration is used. It can also be used. Such a solvent is more preferably photopolymerizable, and specific examples thereof include propylene carbonate and γ-butyrolactone. It is also possible to add various known dyes and sensitizers in order to improve the photopolymerizability. Furthermore, the thermosetting initiator which can harden a photopolymerizable compound by heating can also be used together with a photoinitiator. In this case, by heating after photocuring, it can be expected to further accelerate the polymerization and curing of the photopolymerizable compound.

  A non-homogeneous phase can be formed by curing a photopolymerizable compound alone or a mixture of a plurality of photopolymerizable compounds. Moreover, the non-homogeneous phase according to the present invention can also be formed by curing a mixture of a photopolymerizable compound and a polymer resin not having photocurability. Examples of polymer resins that can be used here include acrylic resins, styrene resins, styrene-acrylic copolymers, polyurethane resins, polyester resins, epoxy resins, cellulose resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymers, Examples include polyvinyl butyral resin. These polymer resins and photopolymerizable compounds need to have sufficient compatibility before photocuring, but various organic solvents, plasticizers, etc. are used to ensure this compatibility. It is also possible. In addition, when using an acrylate as a photopolymerizable compound, it is preferable from a compatible point to select as a polymer resin from an acrylic resin.

  The ratio of the photopolymerizable compound having a silicone skeleton and the compound not having a silicone skeleton is preferably in the range of 15:85 to 85:15 by mass ratio. More preferably, it is the range of 30: 70-70: 30. By setting it in this range, the phase separation between the low refractive index region and the high refractive index region can easily proceed, and the columnar region b can easily be inclined. When the ratio of the photopolymerizable compound having a silicone skeleton is less than the lower limit value or exceeds the upper limit value, the phase separation is difficult to proceed, and the columnar region b is difficult to be inclined. When silicone / urethane / (meth) acrylate is used as a photopolymerizable compound having a silicone skeleton, compatibility with a compound having no silicone skeleton is improved. Thereby, the columnar region b can be inclined even if the mixing ratio of the materials is widened.

3-1-4. Solvent As the solvent for preparing the composition containing the photopolymerizable compound, for example, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, xylene and the like can be used.

3-2. Next, based on FIG. 10, the process (manufacturing method) of the anisotropic optical film of this form is demonstrated. FIG. 10 shows the outline of the manufacturing process of the anisotropic optical film of this embodiment and the outline of the columnar region b grown according to the process. In addition, the manufacturing method of the anisotropic optical film which concerns on this invention shows an example of a manufacturing method, and is not limited to the following method.

3-2-1. Coating Step A composition containing the above-mentioned photopolymerizable compound (hereinafter sometimes referred to as “photocurable composition”) is applied on a suitable substrate (substrate) such as a transparent PET film or a sheet. The photocurable composition layer is provided by forming a film. An anisotropic optical film can be produced by irradiating the photocurable composition layer with light after drying the photocurable composition layer as necessary to volatilize the solvent. Below, what applied the photocurable composition on the base | substrate or provided in the sheet form is called coating film.

3-2-2. Example of forming process of anisotropic optical film The following processes are described in detail as the forming process of the anisotropic optical film according to the present invention.
(Process 1) Coating process of applying a photocurable composition on a substrate and providing a coating film 90 (Process 2) Mask film stacking process of stacking a mask film on the coating film 90 (Process 3) ) Curing process for curing on the coating film 90 by irradiation with one-way diffused light or parallel light

3-2-2-1. Step 1: Coating step In step 1, as a method of providing a composition containing a photopolymerizable compound in a sheet form on a substrate, a normal coating method or printing method is applied. Specifically, air doctor coating, bar coating, blade coating, knife coating, reverse coating, transfer roll coating, gravure roll coating, kiss coating, cast coating, spray coating, slot orifice coating, calendar coating, dam coating, dip coating Coating such as die coating, intaglio printing such as gravure printing, printing such as stencil printing such as screen printing, and the like can be used. When the composition has a low viscosity, a weir having a certain height can be provided around the substrate, and the composition can be cast in the area surrounded by the weir.

3-2-2-2. Process 2: Mask film lamination process In process 2, in order to prevent the oxygen inhibition of a photocurable composition layer and to form the columnar area | region b which is the characteristics of the uniform phase which concerns on this form, and a non-homogeneous phase efficiently. It is preferable to laminate a mask film (hereinafter simply referred to as a mask or the like) that closely contacts the light irradiation side of the photocurable composition layer and locally changes the light irradiation intensity. The material of the mask is not particularly limited. For example, a normal transparent plastic film or the like may be used. However, a light-absorbing filler such as carbon is dispersed in a matrix, and a part of incident light is carbon. Although it is absorbed, the opening may have a configuration that allows light to be sufficiently transmitted.

3-2-2-3. Step 3: Curing Step Next, an apparatus used in the curing step will be described based on FIG. 10, and a specific formation process of the uniform phase and the non-uniform phase will be described.

3-2-2-3-1. Apparatus First, the uniform phase 91 and the non-homogeneous phase 92 are produced mainly by a light source (not shown), an optional directional diffusion element 94, and a movable light shielding plate 93, as shown in FIG. A mask plate 95 and a processing table (not shown) are used.

  The light source irradiates the emitted light on the mask plate 95 directly or through a directional diffusion element, and causes the phase separation to cure while forming a columnar region b (not shown), This is for forming the uniform phase 91 and the non-uniform phase 92. Details of the formation process will be described later.

  As the light source, a short arc ultraviolet light source is usually used. Specifically, a high pressure mercury lamp, a low pressure mercury lamp, a metahalide lamp, a xenon lamp, or the like can be used.

  In particular, in the process of forming a non-homogeneous phase to be described later, it is necessary to irradiate the mask plate 95 with a light beam parallel to the desired scattering center axis Q. In order to obtain such parallel light D, a point light source is disposed, and an optical lens such as a reflection mirror or a Fresnel lens for irradiating the parallel light D between the point light source and the mask plate 95 is disposed. Good. Through such an optical lens, the light emitted from the light source is converted into the parallel light D, and the parallel light D can be irradiated onto the coating film 90 (photocurable composition layer).

The light beam applied to the composition containing the photopolymerizable compound needs to have a wavelength capable of curing the photopolymerizable compound, and usually a light having a wavelength centered at 365 nm of a mercury lamp is used. . If making the using wavelength band non-uniform phase, preferably as the illuminance in the range of ^{0.01mW / cm 2 ~100mW / cm 2} , more preferably 0.1mW ^/ cm ² ~20mW ^/ cm 2 Range. When the illuminance is less than 0.01 mW / cm ² , it takes a long time to cure, so the production efficiency may deteriorate, and when it exceeds 100 mW / cm ² , the photopolymerizable compound cures too quickly, resulting in structure formation. This is because the desired anisotropic diffusion characteristics may not be achieved.

  The directional diffusion element 94 is for imparting directivity to the parallel light D and converting it into the diffused light E. By irradiating the mask plate 95 with the diffused light E, the columnar region b (in the non-uniform phase 92) is formed. FIG. 10 shows a manufacturing method having a directional diffusion element. Here, when the aspect ratio of the columnar region b is 1, the parallel light D can be irradiated to the coating film 90 without using the directional diffusion element 94.

  The directivity diffusing element 94 may be any element that imparts directivity to the incident parallel light D. In order to obtain the diffused light E having directivity in this way, for example, a needle-like filler having a high aspect ratio is contained in the directional diffusion element 94, and the needle-like filler is placed in the same direction in the major axis direction. A method of aligning so as to extend can be employed. Various methods can be used for the directional diffusion element 94 in addition to the method using a needle-like filler. What is necessary is just to arrange | position so that the parallel light D may obtain the diffused light E through the directional diffusion element 94. FIG. A specific example of such a directional diffusion element 94 includes a lenticular lens.

  The light shielding plate 93 is for blocking light emitted from the light source so that the light curable composition is not irradiated with light. The material, size, thickness, and the like of the light shielding plate 93 may be determined as appropriate according to the wavelength and intensity of light emitted from the light source.

  The mask plate 95 is a mask for forming the matrix part A and the columnar part B. In order to form the matrix part A and the columnar part B, the light shielding part 96 that transmits light in part and other light transmitting parts 97.

  The pattern of the mask plate 95 is not particularly limited, and may be produced according to the desired size, quantity, distribution, etc. of the matrix part A and the columnar part B.

  In the example described below, the directional diffusion element 94 and the mask plate 95 are provided separately, but the directional diffusion is achieved by making the light transmitting portion 97 of the mask plate 95 as a directional diffusion element. A configuration without the element 94 is also possible. In view of the trouble of manufacturing the light transmitting part 97 as a directional diffusion element, it is less troublesome to provide the directional diffusion element 94 and the mask plate 95 separately.

  However, when a plurality of optical characteristics are provided in one anisotropic optical film, for example, when a plurality of non-uniform phases having columnar regions b having different aspect ratios are included, the light transmitting portion 97 of the mask plate 95 is provided. By manufacturing as various kinds of directional diffusion elements (different in the aspect ratio), the number of times of light irradiation can be reduced.

  A method for manufacturing the mask is not particularly limited, and a known method can be used. For example, a method of patterning a chromium light-shielding film on synthetic quartz can be used.

  Here, as shown in FIG. 10, the directional diffusion element 94 is disposed so as to protrude from the light shielding plate 93 in a direction along the moving direction of the coating film 90. By doing in this way, the state (a) where all the light emitted from the light source is blocked by the light shielding plate 93, the states (b) to (d) where the diffused light E is irradiated, and the parallel light F are irradiated. Three states can be formed with state (e) being performed.

  Hereinafter, a specific non-homogeneous phase and homogeneous phase formation process in each state divided into states (a) to (e) will be described.

3-2-2-3-2. State (a)
In the process of the region (a) of FIG. 10, the entire coating film 90 is still covered with the light shielding plate 93, and the light emitted from the light source is not irradiated onto the mask plate 95. Therefore, as shown in the state (a) of FIG. 10, the non-uniform phase 92 is not formed, and the entire coating film 90 is in an uncured state.

3-2-2-3-3. Steps in states (b) to (d): non-homogeneous phase forming step In the state (b) in FIG. 10, the movable light-shielding plate 93 is removed, and the mask plate 95 provided below the light-shielding plate 93 is interposed. Then, the diffused light E is applied to the coating film 90 (not shown, but the parallel light D is applied when no directional diffusion element is provided).

  At the place where the diffused light E (or parallel light D) is irradiated onto the coating film 90, phase separation starts from the upper surface of the coating film 90 {state (c) in FIG. 10}, from the upper surface of the coating film 90. The columnar region b (in the non-homogeneous phase 92) begins to be formed and grows gradually. With the formation of the columnar region b (in the non-uniform phase 92), the matrix region a (in the non-uniform phase, not shown) and the uniform phase 91 are also formed.

  More specifically, in the portion irradiated with the diffused light E (or parallel light D), as shown in the state (c) of FIG. 10, the phase separation starts from the upper surface of the coating film 90 and is uniform by the phase separation. A phase 91 and a non-uniform phase 92 begin to form from the top surface to the bottom surface. At this time, as shown in the states (c) to (d) of FIG. 10, the uniform phase 91 and the non-uniform phase 92 have not reached the lower surface, and are between the upper surface and the lower surface of the coating film 90. In this state, a non-homogeneous phase is formed up to the intermediate position. Note that the intermediate position is not limited to the center or center position between the upper surface and the lower surface, and indicates an arbitrary position in a region sandwiched between the upper surface and the lower surface.

  As shown in the states (c) to (d) of FIG. 10, the uniform phase 91 and the non-uniform phase 92 are formed from the upper surface of the coating film 90 to an intermediate position. The coating film 90 is in a state where the region from the upper surface to the intermediate position is cured to form the uniform phase 91 and the non-uniform phase 92, and the region from the intermediate position to the lower surface remains in an uncured state. In this state, no structure is formed. Thus, by stopping the irradiation of the diffused light E (or parallel light D) in the middle, the thickness (long) in the film thickness direction of the anisotropic optical film of the non-uniform phase (columnar region b and matrix region a) ) Can be adjusted. Further, it may reach the lower surface.

  Here, in this step, by adjusting the irradiation intensity and spread of the diffused light E (or parallel light D), the size of the non-homogeneous inner columnar region b (the surface of the anisotropic optical film, The minor axis Sb, the major axis Lb, etc.) can be determined as appropriate.

  The spread of the diffused light E mainly depends on the distance between the directional diffusion element 94 and the coating film 90, the type of the directional diffusion element 94, and the like. As the distance is shortened, the size of the columnar region b decreases, and as the distance is increased, the size of the columnar region b increases. Therefore, the size of the columnar region b can be adjusted by adjusting the distance.

  In this step, the aspect ratio of the diffused light E is not particularly limited, but can be 1 or more and 20 or less, or more than 20. The aspect ratio of the columnar region b is formed substantially corresponding to the aspect ratio. When the aspect ratio of the columnar region b is 1, the aspect ratio of the columnar region b is the same by performing the above process by irradiating the parallel light D without using the directional diffusion element 94. Can be obtained.

  In the coating film 90, after the thickness of the uniform phase and the non-uniform phase is formed in the whole thickness direction of the anisotropic optical film or reaches a predetermined thickness, the movable light shielding plate 93 is formed. And installed on the coating film 90 to shield the diffused light E (or parallel light D). Thereafter, parallel light F is irradiated from the lower surface of the coating film 90 as necessary.

  When the parallel light F is irradiated in the state (e), also in the position where the non-homogeneous phase is not formed in the state (d) {the lower side of the non-uniform region (from the middle position to the lower side of the anisotropic optical film)} Photocuring is started. Since the irradiated light is isotropic light F, a uniform phase is formed here.

  Thus, an anisotropic optical film is formed by the coating film 90 passing through the process of a state (a)-(d) and the process of a state (e).

  In addition, in this anisotropic optical film process, although the irradiation time of the total light is not specifically limited, It is 10 to 180 second, More preferably, it is 10 to 120 second.

Regarding the parallel light F, the anisotropic optical film according to the present invention has a specific internal structure formed in the photocurable composition layer by irradiating light with low illuminance for a relatively long time as described above. It is obtained by. For this reason, unreacted monomer components may remain by such light irradiation alone, resulting in stickiness, which may cause problems in handling properties and durability. In such a case, the residual monomer can be polymerized by additional irradiation with light having a high illuminance of 1000 mW / cm ² or more. When this is done, the parallel light F is used. The light irradiation at this time is preferably performed from the lower surface (light non-irradiated side) of the coating film 90.

3-2-2-4. Other

In the forming method, light is irradiated from one direction of the normal direction of the anisotropic optical film. However, when it is desired to tilt the scattering central axis of the anisotropic optical film from the normal direction, the light irradiation angle By irradiating the coating film 90 with the desired scattering center axis angle, a columnar region b parallel to the scattering center axis angle can be formed.
In addition, in order to make the inclination of the scattering center axis plural, light from a plurality of light sources may be matched with the inclination of each scattering center axis.

4). Use of anisotropic optical film according to the present invention The anisotropic optical film according to the present invention can be suitably used as a diffusion film for lighting, display devices and the like. In particular, it can be used to prevent the screen door effect effect due to the black matrix included in the color filter by using it closer to the viewing side than the color filter of the head mounted display used in the VR technology or the like.

(Example)
Next, although an example and a comparative example explain the present invention still more concretely, the present invention is not limited at all by these examples.

(Preparation of photomask)
Six types of photomasks shown in FIG. 11 were prepared in which a chromium light-shielding film was formed on a synthetic quartz having a thickness of 3 mm. Each of the photomasks having six types of patterns is a pattern A in which square light-shielding portions each having a side of 40 μm are arranged in a lattice pattern through a space having a pitch of 20 μm, and a circular light-shielding portion having a diameter of 40 μm is a space having a pitch of 20 μm. A pattern B arranged in a grid pattern via a circle, a pattern C in which circular light-shielding portions having a diameter of 20 μm are arranged in a random manner via a space having a pitch of 10 μm or more, a pattern D in which the light-shielding portion and the transparent portion of the pattern A are reversed, A pattern E in which the light shielding portion and the transparent portion of the pattern B are reversed, and a pattern F in which the light shielding portion and the transparent portion of the pattern C are reversed.

(Preparation of anisotropic optical film)
According to the following method, the anisotropic optical film which has the non-uniform phase of the single | mono layer or multiple layers of this invention was produced.

  A partition wall having a height of 30 μm was formed of a curable resin using a dispenser on the entire periphery of the edge of the release PET film 1 having a thickness of 100 μm. The following ultraviolet curable resin composition was dropped into this, and the surface of the dropped liquid film was covered with a release PET film 2 having a thickness higher than that of the release PET film 1 and having a thickness of 50 μm. A liquid film of an uncured resin composition layer having a thickness of 5 mm was prepared. In addition, the same thing was used for the composition of the uncured resin composition layer in the examples.

(UV curable resin composition)
Silicone urethane acrylate (refractive index: 1.460, weight average molecular weight: 5,890) 20 parts by mass (trade name: 00-225 / TM18, manufactured by RAHN)
・ Neopentyl glycol diacrylate (refractive index: 1.450) 30 parts by mass (manufactured by Daicel Cytec Co., Ltd., trade name Ebecryl 145)
Bisphenol A EO adduct diacrylate (refractive index: 1.536) 15 parts by mass (Daicel Cytec, trade name: Ebecyl 150)
・ Phenoxyethyl acrylate (refractive index: 1.518) 40 parts by mass (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate PO-A)
・ 2,2-dimethoxy-1,2-diphenylethane-1-one 4 parts by mass (manufactured by BASF, trade name: Irgacure 651)

Subsequently, the liquid film of the uncured resin composition layer was heated at 50 ° C. on a hot plate, and further on the release PET film 2 covering the film liquid, each of the six types of photo prepared above. The mask is laminated so as to be in contact with the chrome light-shielding film surface, and ultraviolet rays that are parallel rays with an irradiation intensity of 5 mW / cm ² are applied from an irradiation unit for incident light of a UV spot light source (product name: L2859-01, manufactured by Hamamatsu Photonics). The anisotropic optical films of Examples 1 to 10 having PET films on both surfaces were produced by direct or direct irradiation through a directional diffusion element for 1 minute.

  Specifically, in the anisotropic optical film production of Examples 1 to 6, photomasks A to F are used in order, and in the anisotropic optical film production of Examples 7 to 9, photomask A is sequentially used. Photomask D was used in producing the anisotropic optical film of Example 10 using ~ C.

  Furthermore, in the production of the anisotropic optical films of Examples 1 to 6 and 10, the directional diffusion element was not used, and in the production of the anisotropic optical films of Examples 7 to 9, the aspect ratio of parallel rays was used. A directional diffusing element that can be changed is used.

  In addition, in the production of the anisotropic optical films of Examples 1 to 9, parallel light rays were irradiated from the angle in the normal direction (angle 0 °) with respect to the liquid film plane of the uncured resin composition layer. However, in the production of the anisotropic optical film of Example 10, parallel rays were irradiated from an angle inclined by 15 ° with respect to the normal direction.

  The production conditions of the anisotropic optical films of Examples 1 to 10 are shown in Table 1, and the characteristics are shown in Table 2. The optical profiles of Examples 1, 2, and 10 are shown in FIG.

(Preparation of anisotropic optical films of Comparative Examples 1 and 2)
In the production of the anisotropic optical films of Examples 1 and 7, production was performed in the same manner except that a photomask was not used, and the anisotropic optical films of Comparative Examples 1 and 2 were produced in order.

  In the production of the anisotropic optical film of Comparative Example 1, the height of the partition wall was changed to 20 μm, and a liquid film of an uncured resin composition layer having a thickness of 20 μm was produced, and then a photomask was used. The anisotropic optical film of Comparative Example 3 was produced.

  The production conditions of the anisotropic optical films of Comparative Examples 1 to 3 are shown in Table 1, and the characteristics are shown in Table 2.

(Preparation of isotropic optical film of Comparative Example 4)
Silicone resin fine particles (trade name: Tospearl 145, manufactured by Momentive Performance Materials Co., Ltd.) as fine particles having a refractive index different from that of the pressure-sensitive adhesive composition with respect to 100 parts by mass of the acrylic pressure-sensitive adhesive composition having the refractive index of 1.47 shown below. ) Was added, and the mixture was stirred with an agitator for 30 minutes to disperse the fine particles to obtain a coating solution. Using a comma coater, the coating solution is applied onto a release PET film 3 having a thickness of 38 μm so that the film thickness after drying the solvent is 25 μm, dried, and isotropically diffused with PET. An adhesive layer was prepared. Further, the surface of the isotropic diffusion adhesive layer is laminated with a release PET film 4 having a thickness of 38 μm, which has a higher peeling force than that of the release PET film 3, and has PET films on both sides. An isotropic optical film was produced.
The characteristics of the produced comparative optical film 4 are shown in Table 1 below. The optical profiles of Comparative Examples 1, 2, and 4 are shown in FIG.

(Acrylic adhesive composition)
・ Acrylic adhesive (total solid content concentration 18.8%, solvent: ethyl acetate, methyl ethyl ketone) 100 parts by mass (manufactured by Soken Chemical Co., Ltd., trade name: SK Dyne TM206)
・ Isocyanate-based curing agent 0.5 parts by mass (manufactured by Soken Chemical Co., Ltd., trade name: L-45)
・ 0.2 parts by mass of epoxy curing agent (manufactured by Soken Chemical Co., Ltd., trade name: E-5XM)

  From the results shown in Table 2, the minimum linear transmittances of the anisotropic optical films of Examples 1 to 10 are all 20% or more, and the maximum linear transmittances are all 50% or more. When used, it is possible to suppress a decrease in luminance. In addition, since the diffusion width was as wide as 30 ° or more, the diffusion performance was also high (see the optical profile in FIG. 12).

  The above-described characteristics of Examples 1 to 10 are that the brightness and contrast of the display device are good, the viewing angle is widened by diffusion performance, the black matrix of the head mounted display is difficult to see, the reflective display and the semi-transmissive It can be expected to improve brightness and contrast when used in a semi-reflective display. In particular, since the anisotropic optical films of Examples 3, 6, and 9 have a large diffusion width and excellent diffusion performance, in addition to the effect of further widening the viewing angle, no glare is confirmed. It can be expected to be effective for use in large, head-mounted displays.

  On the other hand, since the anisotropic optical films of Comparative Examples 1 and 2 have a low minimum linear transmittance, when used in a display device, the brightness and contrast of the display device may be greatly reduced. Further, the anisotropic optical film of Comparative Example 3 has a relatively good minimum linear transmittance, but has a narrow diffusion width, so that sufficient diffusion performance cannot be obtained when used as a display device. Furthermore, the isotropic comparative optical film of Comparative Example 4 has a low value for both the minimum linear transmittance and the maximum linear transmittance. Therefore, although the diffusion performance is excellent, the brightness and contrast are reduced. Since the optical film becomes large and the optical film has no anisotropy, image blur may occur (see the optical profile in FIG. 13).

  As described above, since the anisotropic optical films of Examples 1 to 10 of the present invention have high diffusion performance and high minimum and maximum linear transmittance, they have well-balanced optical characteristics and display. When used in an apparatus, it is expected that the reduction in luminance and contrast can be suppressed while having the effect of widening the viewing angle and eliminating the black matrix.

DESCRIPTION OF SYMBOLS 1 Anisotropic optical film 2, 3 Anisotropic optical film surface 10 Matrix part A
20 Column B
30,91 Non-homogeneous phase (matrix part A or columnar part B)
40,92 homogeneous phase (matrix part A or columnar part B)
50 Matrix area a
60 Columnar area b
70 light source 80 detector 90 coating film 93 light-shielding plate 94 directional diffusion element 95 mask 96 light-shielding part 97 light-transmitting part

Claims (10)

An anisotropic optical film in which the diffusivity of light emitted from the other surface changes depending on the incident angle of light incident from one surface,
The anisotropic optical film has a matrix portion A and a cross-sectional shape in a plane extending from one surface of the anisotropic optical film to the other surface and parallel to the plane direction of the anisotropic optical film. A columnar portion B having a diameter, a major axis length, a longest length in a cross-sectional shape, or a longest length in a polygonal shape inscribed in the cross-sectional shape of 10 μm to 100 μm,
Either one of the matrix part A or the columnar part B is a matrix region a and a diameter of a cross-sectional shape in a plane parallel to the surface of the anisotropic optical film, a long axis length, the longest length in the cross-sectional shape, Or, the maximum value of the longest length in the polygonal shape inscribed in the cross-sectional shape is a non-homogeneous phase including a plurality of columnar regions b of 0.5 μm to 20 μm, and the other is only the matrix region a A homogeneous phase comprising
The matrix region a and the plurality of columnar regions b have different absolute refractive indexes,
The plurality of columnar regions b extends from one surface of the anisotropic optical film toward the other surface, and is an anisotropic optical film.   The anisotropic optical film according to claim 1, wherein the matrix part A is a non-homogeneous phase and the columnar part B is a homogeneous phase.   The anisotropic optical film according to claim 1, wherein the columnar part B is inclined by 0 ° to 70 ° with respect to a normal direction of the surface of the anisotropic optical film.   The columnar part B has a rectangular cross-sectional shape in a plane parallel to the anisotropic optical film surface, and the ratio of the length of the short side of the rectangular shape to the long side is 1: 1 to 1. The anisotropic optical film according to any one of claims 1 to 3, wherein the anisotropic optical film is: 20.   The anisotropic optics according to claim 1, wherein the matrix part A and the columnar part B, which are observed from the normal direction of the surface of the anisotropic optical film, are formed in a lattice shape. the film.   The columnar part B has a circular or elliptical cross-sectional shape in a plane parallel to the anisotropic optical film surface, and the ratio of the length between the shortest diameter and the longest diameter of the circular or elliptical shape is The anisotropic optical film according to any one of claims 1 to 3, wherein the ratio is 1: 1 to 1:20.   The anisotropic structure according to any one of claims 1 to 6, wherein the columnar region b is inclined by 0 ° to 70 ° with respect to a normal direction of the surface of the anisotropic optical film. Optical film.   The plurality of columnar regions b have a circular or elliptical cross-sectional shape in a plane parallel to the anisotropic optical film surface, and the length of the shortest diameter and the longest diameter of the circular or elliptical shape. The anisotropic optical film according to claim 1, wherein the ratio is 1: 1 to 1:20.   The plurality of columnar regions b observed from the normal direction of the anisotropic optical film surface are formed in a circular or elliptical shape, and the shortest diameter of the circular or elliptical shape and the length of the longest diameter The anisotropic optical film according to claim 1, wherein the ratio of is more than 1:20.   The inclination angle of the columnar part B with respect to the normal direction of the anisotropic optical film surface and the inclination angle of the columnar region b with respect to the normal direction of the anisotropic optical film surface are substantially the same. The anisotropic optical film according to any one of claims 3 to 9, wherein: