JP7620619B2 - Anisotropic light-diffusing film and display device - Google Patents

Description

The present invention relates to an anisotropic light-diffusing film and a display device equipped with the anisotropic light-diffusing film.

Display devices, such as transmissive TN liquid crystal displays, have problems related to viewing angle dependency, such as a decrease in brightness and contrast and a change in color (tone inversion) from that seen from the front when viewed at an angle in a certain direction.

To eliminate this viewing angle dependency, anisotropic optical bodies are used in which the linear transmittance [(amount of light transmitted in the linear direction of incident light) / (amount of incident light)] changes depending on the angle of incidence of light.

For example, in Patent Document 1, the problems of brightness and color change due to viewing angle are improved by using an anisotropic optical film in a display device, in which the direction in which color change in the display device is minimized and the central scattering axis are within a specific angular range.

Patent Publication 2015-127819

However, in light of the increasing diversification of display methods and display sizes of display devices, there is a demand for anisotropic optical bodies that have even better effects in improving viewing angle dependence.

Therefore, the objective of the present invention is to provide an anisotropic light-diffusing film that has a better effect of improving viewing angle dependence in terms of brightness and color change due to viewing angle than conventional films.

We discovered that the above problems could be solved by creating an anisotropic light-diffusing film with specific properties, and thus completed the present invention.

The present invention (1) is
An anisotropic light-diffusing film having a linear transmittance, which is (amount of transmitted light in a linear direction of incident light)/(amount of incident light), that changes depending on the angle of incidence of light,
the anisotropic light-diffusing film has a matrix region and a plurality of columnar regions having a refractive index different from that of the matrix region;
Furthermore, the anisotropic light-diffusing film has one scattering central axis,
In the tilt direction of the scattering central axis,
The linear transmittance at an incident angle of 60° is 10% or less,
The anisotropic light-diffusing film is characterized in that the diffuse transmittance of light at an incident angle of 0° in the direction of a polar angle of 60° is 0.001% or more.
The present invention (2) is
If the polar angle between the surface normal direction of the anisotropic light-diffusing film and the scattering central axis direction is defined as the scattering central axis angle,
The anisotropic light-diffusing film according to the above aspect (1) is characterized in that the scattering central axis angle of the anisotropic light-diffusing film is 20° to 60°.
The present invention (3) is
The anisotropic light-diffusing film according to the above invention (1) or (2) is characterized in that the haze value of the anisotropic light-diffusing film is 75% or more.
The present invention (4) is
The anisotropic light-diffusing film according to any one of the above aspects (1) to (3) is characterized in that the thickness of the anisotropic light-diffusing film is 15 μm to 100 μm.
The present invention (5) is
The plurality of columnar regions of the anisotropic light-diffusing film are
The anisotropic light diffusing film is oriented and extends from one surface to the other surface,
The anisotropic light-diffusing film according to any one of the above aspects (1) to (4) is characterized in that the aspect ratio of the columnar regions, which is the average long axis/average short axis of the columnar regions in a cross section perpendicular to the column axis of the columnar regions of the anisotropic light-diffusing film, is less than 2.
The present invention (6) is
A liquid crystal display device, characterized in that the anisotropic light-diffusing film according to any one of the above aspects (1) to (5) is laminated on the viewing side of a liquid crystal layer.
The present invention (7) is
The organic EL display device is characterized in that the anisotropic light-diffusing film according to any one of the above aspects (1) to (5) is laminated on the viewing side of the light-emitting layer.

According to the present invention, it is possible to provide an anisotropic light-diffusing film that has a better effect of improving viewing angle dependence in terms of brightness and color change due to viewing angle than conventional films.

FIG. 2 is an explanatory diagram showing the incident light angle dependency of an anisotropic light-diffusing film. FIG. 2 is a top view showing the surface structure of an anisotropic light-diffusing film. 1 is a schematic diagram illustrating an example of an anisotropic light-diffusing film. 1 is a three-dimensional polar coordinate representation for explaining the scattering central axis in an anisotropic light-diffusing film. 1 is an optical profile of an anisotropic light-diffusing film. FIG. 2 is a schematic diagram showing a method for measuring the incident light angle dependency of an anisotropic light-diffusing film. FIG. 2 is a schematic diagram showing a method for producing an anisotropic light-diffusing film according to the present invention, including optional steps 1-3.

Below, we will provide a brief explanation of the anisotropic light-diffusing film of the present invention, followed by an explanation of its structure, physical properties, manufacturing method, and specific uses.

<<<<<Anisotropic light diffusion film>>>>
An anisotropic light-diffusing film is a film having optical anisotropy, in which the linear transmittance [(amount of incident light transmitted in a linear direction)/(amount of incident light)] changes depending on the angle of incidence of light. That is, with respect to light incident on an anisotropic light-diffusing film, incident light within a specific angle range is transmitted while maintaining linearity, and incident light within other angle ranges exhibits diffusivity.

For example, the anisotropic light diffusion film shown in Figure 1 exhibits diffusivity when the incident angle is between 20° and 50°, but does not exhibit diffusivity at other incident angles and exhibits linear transmittance.

<<<<Structure>>>
The anisotropic light-diffusing film of the present invention has a matrix region and a plurality of columnar regions having a refractive index different from that of the matrix region. The plurality of columnar regions included in the anisotropic light-diffusing film are usually configured to be oriented and extend from one surface to the other surface of the anisotropic light-diffusing film (see FIG. 3, etc.).

Here, the difference in refractive index means that there is a difference to the extent that at least a portion of the light incident on the anisotropic light-diffusing film is reflected at the interface between the matrix region and the columnar region. Although there are no particular limitations, for example, the difference in refractive index between the matrix region and the columnar region may be 0.001 or more.

<<Columnar Region>>
The length of the columnar region is not particularly limited, and may extend from one surface of the anisotropic light-diffusing film to the other surface, or may be short enough not to reach from one surface to the other surface.

The cross-sectional shape of the multiple columnar regions contained in the anisotropic light-diffusing film in a cross section perpendicular to the column axis of the anisotropic light-diffusing film can be a shape having a short diameter and a long diameter.

The cross-sectional shape of the columnar region is not particularly limited, and can be, for example, circular, elliptical, or polygonal. In the case of a circle, the minor axis and the major axis are equal, in the case of an ellipse, the minor axis is the length of the minor axis, and the major axis is the length of the major axis, and in the case of a polygon, the shortest length within the polygon can be the minor axis, and the longest length can be the major axis. Figure 2 shows the columnar region as viewed from the surface direction of the anisotropic light-diffusing film. In Figure 2, LA represents the major axis, and SA represents the minor axis.

The short and long diameters of the columnar regions can be determined by observing a cross section of the anisotropic light-diffusing film perpendicular to the column axis with an optical microscope, measuring the short and long diameters of 20 arbitrarily selected columnar regions, and taking the average value of these.

<Minor diameter>
In the anisotropic light-diffusing film, the average value of the minor axes of the columnar regions (average minor axis) is preferably 0.5 μm or more, more preferably 1.0 μm or more, and even more preferably 1.5 μm or more. On the other hand, the average minor axis of the columnar regions is preferably 5.0 μm or less, more preferably 4.0 μm or less, and even more preferably 3.0 μm or less. The lower and upper limits of the minor axes of the columnar regions can be appropriately combined.

<Long diameter>
In the anisotropic light-diffusing film, the average value of the major axis of the columnar region (average major axis) is preferably 0.5 μm or more, more preferably 1.0 μm or more, and even more preferably 1.5 μm or more. On the other hand, the average major axis of the columnar region is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. The average major axis of the columnar region is preferably shorter than the length of the columnar region. In this way, it is possible to increase the linear light transmittance of the anisotropic light-diffusing film. The lower limit and upper limit of the major axis of the columnar region can be appropriately combined.

The ratio of the average long diameter to the average short diameter of the columnar region (average long diameter/average short diameter), i.e., the aspect ratio, is not particularly limited, but can be, for example, 1 to 20.

Figure 2(a) shows an anisotropic light-diffusing film in which the aspect ratio of the columnar region is 2 to 20, and Figure 2(b) shows an anisotropic light-diffusing film in which the aspect ratio of the columnar region is 1 or more and less than 2.

When the aspect ratio is between 1 and 2, and light is irradiated parallel to the axial direction of the columnar region, the transmitted light is diffused isotropically (see Figure 3(a)). On the other hand, when the aspect ratio is between 2 and 20, and light is irradiated parallel to the axial direction, the light is diffused anisotropically according to the aspect ratio (see Figure 3(b)).

An anisotropic light-diffusing film may contain multiple columnar regions having one aspect ratio, or may contain multiple columnar regions having different aspect ratios.

<<<Scattering center axis>>>
The anisotropic light-diffusing film has a scattering central axis. The scattering central axis and the orientation direction (extension direction) of the columnar regions are usually parallel to each other. Being parallel means that the law of refractive index (Snell's law) is satisfied, and it is not necessary for the rays to be strictly parallel.

Snell's law states that when light is incident on the interface between a medium with a refractive index n1 and a medium with a refractive index n2, the relationship between the incident light angle θ1 and the refraction angle θ2 is n1 sin θ1 = n2 sin θ2. For example, if n1 = 1 (air) and n2 = 1.51 (anisotropic light-diffusing film), when the incident light angle is 30°, the orientation direction (refraction angle) of the columnar region is approximately 19°. Even if the incident light angle and refraction angle differ in this way, as long as they satisfy Snell's law, they are included in the concept of parallelism in this invention.

Next, the scattering central axis P in the anisotropic light-diffusing film will be described in more detail with reference to Figure 4. Figure 4 is a three-dimensional polar coordinate representation for explaining the scattering central axis P in the anisotropic light-diffusing film.

The central scattering axis refers to the direction that coincides with the angle of incidence of light at which the light diffusion properties are approximately symmetrical across the angle of incidence when the angle of incidence of light on the anisotropic light-diffusing film is changed. The angle of incidence of light in this case is approximately the center (the center of the diffusion region) between the minimum values in the optical profile (Figure 5), which is a plot of the linear transmittance for each angle of incidence of light measured through the anisotropic light-diffusing film.

In a three-dimensional polar coordinate representation as shown in Figure 4, the central scattering axis can be expressed by the polar angle θ and the azimuthal angle φ, where the surface of the anisotropic light-diffusing film is the xy plane and the normal to the surface of the anisotropic light-diffusing film is the z axis.

Here, the polar angle θ (-90°<θ<90°) between the normal to the anisotropic light-diffusing film (z-axis shown in Figure 4) and the columnar region can be defined as the scattering central axis angle. In the process of photocuring the uncured resin composition layer to form a columnar region, the axial angle of the columnar region can be adjusted to the desired range by changing the direction of the irradiated light beam.

The scattering central axis angle θ of the anisotropic light diffusion film is not particularly limited, but is preferably 20° to 60°, and more preferably 20° to 50°.

By setting the scattering central axis angle θ in this manner, it is possible to achieve the desired angle dependence.

<<<Optical profile>>>
As shown in Fig. 5, the anisotropic light diffusion film has light diffusion property that depends on the angle of incident light, that is, the linear transmittance varies depending on the angle of incident light. Hereinafter, the curve showing the light diffusion property dependency on the angle of incident light, as shown in Fig. 5, is referred to as the "optical profile".

An optical profile can be created, for example, as follows:

As shown in FIG. 6, an anisotropic light-diffusing film is placed between a light source 1 and a detector 2. In this embodiment, the incident light angle is set to 0° when the irradiated light I from the light source 1 is incident from the normal direction of the anisotropic light-diffusing film. The anisotropic light-diffusing film is placed so that it can be rotated arbitrarily around a straight line V as the axis of rotation, and the light source 1 and the detector 2 are fixed. That is, according to this method, a sample (anisotropic light-diffusing film) is placed between the light source 1 and the detector 2, and the linear transmittance that passes through the sample in a straight line and enters the detector 2 is measured while changing the angle around the straight line V on the sample surface as the axis of rotation. Then, this linear transmittance is plotted for each angle to create an optical profile.

Although the optical profile does not directly express light diffusion, if we interpret it as meaning that a decrease in linear transmittance means an increase in diffuse transmittance, it can be said to generally indicate light diffusion.

A typical isotropic light diffusion film exhibits a mountain-shaped optical profile that peaks at an incident light angle of around 0°.

In an anisotropic light diffusion film, for example, when the scattering central axis angle is 0° (Figure 5), the film exhibits a valley-shaped optical profile in which the linear transmittance is small at incident light angles near 0° (-20° to +20°) and increases as the incident light angle (absolute value) increases.

In this way, anisotropic light diffusion films have the property that the incident light is strongly diffused in the incident light angle range close to the central scattering axis, but the diffusion weakens and the in-line transmittance increases in the incident light angle range beyond that.

When the scattering central axis angle is other than 0°, the optical profile moves so that the linear transmittance decreases at incident light angles near the scattering central axis angle (the valley of the optical profile moves toward the scattering central axis angle).

<<<Lin-line transmittance>>>
As shown in FIG. 5, the linear transmittance of light incident on the anisotropic light-diffusing film at an incident angle at which the linear transmittance is maximized is referred to as the maximum linear transmittance.

As shown in Figure 5, the linear transmittance of light incident on an anisotropic light-diffusing film at an incident angle at which the linear transmittance is minimum is called the minimum linear transmittance.

As shown in Figure 5, the angular range of the two incident light angles for a linear transmittance that is intermediate between the maximum linear transmittance and the minimum linear transmittance is called the diffusion region (the width of this diffusion region is the "diffusion width"), and the incident light angle range excluding this is called the non-diffusion region (transmitting region).

The linear transmittance of the anisotropic light diffusion film at an incident angle of 60° in the inclined orientation of the scattering central axis is preferably 10% or less, more preferably 5% or less, and particularly preferably less than 2.5%.

The linear transmittance can be adjusted by the refractive index of the material of the anisotropic light-diffusing film (the refractive index difference when multiple resins are used), the film thickness of the coating, UV illuminance, the temperature during structure formation, the irradiation angle during UV irradiation, and other curing conditions. The linear transmittance at an incident angle of 60° tends to decrease, for example, when the irradiation angle during UV irradiation is farther from the normal direction of the coating film, the coating film thickness is thicker, the coating film temperature is higher, and the refractive index difference when multiple resins are used is larger.

<<<<Diffuse transmittance in the direction of a polar angle of 60° in the tilt direction of the central scattering axis for light with an incident angle of 0°>>>
A light source is arranged in the normal direction (incident angle = 0°) of one surface of the anisotropic light-diffusing film, and a detector is arranged on the other surface. The normal direction on the detector side is set to a polar angle θ = 0°, and the luminance is measured while changing the polar angle of the detector. The diffuse transmittance is a relative value with the luminance in the normal direction (polar angle θ = 0°) when no anisotropic light-diffusing film is used being 100%.

The diffuse transmittance of the anisotropic light diffusion film in the direction of a polar angle of 60° in the inclination direction of the scattering central axis of light with an incident angle of 0° is preferably 0.001% or more. The upper limit of this value is not particularly limited, but is preferably 0.01% or less, and more preferably 0.005% or less.

By setting the linear transmittance of the anisotropic light-diffusing film at an incident angle of 60° within the appropriate range described above, and setting the diffuse transmittance of light at an incident angle of 0° into the direction of a polar angle of 60° in the inclination direction of the scattering central axis within this range, light can be diffused sufficiently up to a viewing angle of approximately 80°.

The diffuse transmittance of light with an incident angle of 0° on an anisotropic light diffusion film in the direction of a polar angle of 60° in the inclination direction of the scattering central axis tends to increase as the coating film becomes thicker and the temperature of the coating film becomes higher during UV irradiation. In addition, when UV irradiation is performed on the coating film, the above numerical range is likely to be satisfied if the irradiation angle is 20° to 60° from the normal direction of the coating film.

<<<Haze value>>>
The haze value (total haze) of an anisotropic light-diffusing film is an index showing the diffusibility of the anisotropic light-diffusing film. The larger the haze value, the higher the diffusibility of the anisotropic light-diffusing film.

The method for measuring the haze value is not particularly limited and can be measured by a known method. For example, it can be measured according to JIS K7136-1:2000 "Determination of haze for plastics - transparent materials."

The haze value of the anisotropic light-diffusing film is not particularly limited, but is preferably 75% or more. By setting it in this range, the effect of the present invention can be further enhanced.

The haze value can be adjusted by the refractive index of the material of the anisotropic light-diffusing film (or the difference in refractive index when multiple resins are used), the thickness of the coating film, and curing conditions such as UV illuminance and temperature during structure formation. The haze value tends to increase, for example, when UV irradiation is performed, the irradiation angle is closer to the normal direction of the uncoated film, the coating layer is thicker, the coating temperature is higher, and the refractive index difference is larger when multiple resins are used.

<<Thickness>>
The thickness of the anisotropic light-diffusing film is not particularly limited, but is preferably 15 μm to 100 μm, and more preferably 30 μm to 60 μm. By setting the thickness in such a range, it is possible to reduce the manufacturing costs, such as the cost of materials and the cost required for UV irradiation, while ensuring a sufficient visual dependency improving effect.

The manufacturing method for anisotropic light diffusion film is described below.

<<<<Production of anisotropic light-diffusing film>>>
<<Ingredients>>
The raw materials of the anisotropic light-diffusing film will be described in the following order: (1) photopolymerizable compound, (2) photoinitiator, (3) blending amount, and other optional components.

<Photopolymerizable Compound>
The photopolymerizable compound is a material that is composed of a photopolymerizable compound selected from a macromonomer, polymer, oligomer, or monomer having a radically polymerizable or cationic polymerizable functional group and a photoinitiator, and that polymerizes and hardens when irradiated with ultraviolet light and/or visible light.

Here, even if the anisotropic light-diffusing film is made of only one material, differences in density will result in differences in refractive index. The curing speed will be faster in areas where the UV irradiation intensity is strong, and the polymerized and cured material will move around the cured area, resulting in the formation of areas with a high refractive index and areas with a low refractive index. Note that (meth)acrylate means that it can be either acrylate or methacrylate.

Radical polymerizable compounds mainly contain one or more unsaturated double bonds in the molecule. Specifically, acrylic oligomers called epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate, polybutadiene acrylate, silicone acrylate, etc., and 2-ethylhexyl acrylate, isoamyl acrylate, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, isonorbornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate, Examples of the acrylate monomer include acrylate monomers such as 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, ditrimethylolpropane tetraacrylate, and dipentaerythritol hexaacrylate. These compounds may be used alone or in combination. Methacrylates can also be used in the same manner, but acrylates are generally preferred over methacrylates because they have a faster photopolymerization rate.

As a cationic polymerizable compound, a compound having one or more epoxy groups, vinyl ether groups, or oxetane groups in the molecule can be used. Examples of the compound having an epoxy group include 2-ethylhexyl diglycol glycidyl ether, glycidyl ether of biphenyl, diglycidyl ethers of bisphenols such as bisphenol A, hydrogenated bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethyl bisphenol A, tetramethyl bisphenol F, tetrachloro bisphenol A, and tetrabromo bisphenol A, polyglycidyl ethers of novolac resins such as phenol novolac, cresol novolac, brominated phenol novolac, and ortho-cresol novolac, diglycidyl ethers of alkylene glycols such as ethylene glycol, polyethylene glycol, polypropylene glycol, butanediol, 1,6-hexanediol, neopentyl glycol, trimethylolpropane, 1,4-cyclohexanedimethanol, an EO adduct of bisphenol A, and a PO adduct of bisphenol A, and glycidyl esters such as a glycidyl ester of hexahydrophthalic acid and a diglycidyl ester of dimer acid.

Further examples of compounds having an epoxy group include 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, methylenebis(3,4-epoxycyclohexa and alicyclic epoxy compounds such as, but not limited to, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, tetra(3,4-epoxycyclohexylmethyl)butane tetracarboxylate, and di(3,4-epoxycyclohexylmethyl)-4,5-epoxytetrahydrophthalate.

Examples of compounds having a vinyl ether group include, but are not limited to, 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, trimethylolpropane trivinyl ether, propenyl ether propylene carbonate, etc. Vinyl ether compounds are generally cationic polymerizable, but can also be radically polymerized by combining them with acrylates.

Compounds having an oxetane group that can be used include 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene and 3-ethyl-3-(hydroxymethyl)-oxetane.

The above cationic polymerizable compounds may be used alone or in combination. The photopolymerizable compounds are not limited to those mentioned above.

In order to generate a sufficient refractive index difference, a fluorine atom (F) may be introduced into the photopolymerizable compound to lower the refractive index, or a sulfur atom (S), a bromine atom (Br), or various metal atoms may be introduced into the photopolymerizable compound to increase the refractive index. Furthermore, as disclosed in JP-A-2005-514487, it is also effective to add functional ultrafine particles, which are made of ultrafine particles of a metal oxide having a high refractive index such as titanium oxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), or tin oxide (SnO _x ), to the above-mentioned photopolymerizable compound, to which a photopolymerizable functional group such as an acrylic group, a methacrylic group, or an epoxy group has been introduced on the surface of the ultrafine particles.

It is preferable to use a photopolymerizable compound having a silicone skeleton as the photopolymerizable compound. The photopolymerizable compound having a silicone skeleton is oriented according to its structure (mainly ether bonds) and polymerizes and hardens to form a low refractive index region, a high refractive index region, or a low refractive index region and a high refractive index region. By using a photopolymerizable compound having a silicone skeleton, it becomes easier to tilt the columnar region, improving the light collection in the front direction. The low refractive index region corresponds to either the columnar region or the matrix region, and the other corresponds to the high refractive index region.

In the low refractive index region, it is preferable that the amount of silicone resin, which is a cured product of a photopolymerizable compound having a silicone skeleton, is relatively large. This makes it easier to tilt the scattering axis further, improving the light collection in the forward direction. Silicone resin contains more silicon (Si) than compounds that do not have a silicone skeleton, so the relative amount of silicone resin can be confirmed by using an EDS (energy dispersive X-ray spectrometer) using silicon as an indicator.

The photopolymerizable compound having a silicone skeleton is a monomer, oligomer, prepolymer, or macromonomer having a radically polymerizable or cationic polymerizable functional group. Examples of radically polymerizable functional groups include acryloyl groups, methacryloyl groups, and allyl groups, and examples of cationic polymerizable functional groups include epoxy groups and oxetane groups. There are no particular limitations on the type and number of these functional groups, but it is preferable to have a polyfunctional acryloyl group or methacryloyl group because the more functional groups there are, the higher the crosslinking density and the more likely the refractive index difference is to occur. In addition, compounds having a silicone skeleton may have insufficient compatibility with other compounds due to their structure, but in such cases, the compatibility can be increased by urethane conversion. In this embodiment, a silicone urethane (meth)acrylate having an acryloyl group or methacryloyl group at the end 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 in the range of 2,000 to 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-diffusing film of Anisotropic Light-Diffusing Film 0 becomes more likely to be oriented. As the silicone resin becomes more oriented, the central scattering axis becomes more likely to be tilted.

An example of a silicone skeleton is that shown in the following general formula (1). In general formula (1), R1, R2, R3, R4, R5, and R6 each independently have a functional group such as a methyl group, an alkyl group, a fluoroalkyl group, a phenyl group, an epoxy group, an amino group, a carboxyl group, a polyether group, an acryloyl group, or a methacryloyl group. In general formula (1), n is preferably an integer from 1 to 500.

When a photopolymerizable compound having a silicone skeleton is blended with a compound not having a silicone skeleton to form an anisotropic light-diffusing film, low refractive index regions and high refractive index regions are easily formed separately, which results in a stronger degree of anisotropy, which is preferable.

Compounds that do not have a silicone skeleton can be photopolymerizable compounds, as well as thermoplastic resins and thermosetting resins, and these can also be used in combination.

As the photopolymerizable compound, a polymer, oligomer, or monomer having a radically polymerizable or cationic polymerizable functional group (however, it does not have a silicone skeleton) can be used.

Thermoplastic resins include polyester, polyether, polyurethane, polyamide, polystyrene, polycarbonate, polyacetal, polyvinyl acetate, acrylic resins, and their copolymers and modifications. When using a thermoplastic resin, it is dissolved in a solvent that dissolves the thermoplastic resin, and after coating and drying, a photopolymerizable compound having a silicone skeleton is cured with ultraviolet light to form an anisotropic light-diffusing film.

Examples of thermosetting resins include epoxy resins, phenolic resins, melamine resins, urea resins, unsaturated polyesters, and their copolymers and modified products. When using a thermosetting resin, a photopolymerizable compound having a silicone skeleton is cured with ultraviolet light, and then heated appropriately to harden the thermosetting resin and form an anisotropic light-diffusing film.

The most preferred compounds that do not have a silicone skeleton are photopolymerizable compounds, which offer excellent productivity because the low and high refractive index regions are easy to separate, there is no need for a solvent when using thermoplastic resins, and no drying process is required, and there is no need for a heat curing process like with thermosetting resins.

<Photoinitiator>
Examples of photoinitiators capable of polymerizing radically polymerizable compounds include benzophenone, benzil, Michler's ketone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-diethoxyacetophenone, benzil dimethyl ketal, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl ether, and 1-methyl-2-phenylpropan-1-one. phenyl 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)phenyl]titanium, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, etc. Furthermore, these compounds may be used alone or in combination.

A photoinitiator for a cationic polymerizable compound is a compound that generates an acid when irradiated with light and can polymerize the above-mentioned cationic polymerizable compound using the generated acid. Generally, onium salts and metallocene complexes are preferably used.

As the onium salt, a diazonium salt, a sulfonium salt, an iodonium salt, a phosphonium salt, a selenium salt, etc. are used, and as the counter ion, an anion such as BF4-, PF6-, AsF6-, SbF6-, etc. are used. Specific examples include 4-chlorobenzenediazonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, (4-phenylthiophenyl)diphenylsulfonium hexafluoroantimonate, (4-phenylthiophenyl)diphenylsulfonium hexafluorophosphate, bis[4-(diphenylsulfonio)phenyl]sulfide-bis-hexafluoroantimonate, bis[4-(diphenylsulfonio)phenyl]sulfide-bis-hexafluoroantimonate, and bis[4-(diphenylsulfonio)phenyl]sulfide-bis-hexafluorophosphate. Examples of the hexafluorophosphate include, but are not limited to, fluorophosphate, (4-methoxyphenyl)diphenylsulfonium hexafluoroantimonate, (4-methoxyphenyl)phenyliodonium hexafluoroantimonate, bis(4-t-butylphenyl)iodonium hexafluorophosphate, benzyltriphenylphosphonium hexafluoroantimonate, triphenylselenium hexafluorophosphate, (η5-isopropylbenzene)(η5-cyclopentadienyl)iron(II) hexafluorophosphate, etc. Furthermore, these compounds may be used alone or in combination.

The photoinitiator is blended in an amount of 0.01 to 10 parts by weight, preferably 0.1 to 7 parts by weight, and more preferably 0.1 to 5 parts by weight, per 100 parts by weight of the photopolymerizable compound. This is because if it is blended in an amount of less than 0.01 parts by weight, the photocurability decreases, and if it is blended in an amount of more than 10 parts by weight, it will cause problems such as only the surface curing and decreasing the internal curability, as well as discoloration and inhibition of the formation of columnar structures.

<Other ingredients>
The photoinitiator is usually used by directly dissolving the powder in the photopolymerizable compound, but if the solubility is poor, the photoinitiator can be used by dissolving it in a very small amount of solvent in advance at a high concentration. It is more preferable that such a solvent is photopolymerizable, and specific examples include propylene carbonate and γ-butyrolactone. It is also possible to add various known dyes and sensitizers to improve photopolymerizability.

Furthermore, a heat-curing initiator capable of curing the photopolymerizable compound by heating can be used together with the photoinitiator. In this case, it is expected that the polymerization and curing of the photopolymerizable compound can be further promoted and completed by heating after photocuring. An anisotropic light-diffusing film can be formed by curing a single photopolymerizable compound or a composition in which multiple photopolymerizable compounds are mixed.

An anisotropic light-diffusing film can also be formed by curing a mixture of a photopolymerizable compound and a polymer resin that is not photocurable.

Polymer resins that can be used here include acrylic resin, styrene resin, styrene-acrylic copolymer, polyurethane resin, polyester resin, epoxy resin, cellulose-based resin, vinyl acetate-based resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral resin, etc. These polymer resins and photopolymerizable compounds must have sufficient compatibility before photocuring, and various organic solvents and plasticizers can be used to ensure this compatibility.

When using an acrylate as the photopolymerizable compound, it is preferable to select an acrylic resin as the polymer resin in terms of compatibility.

The ratio of the photopolymerizable compound having a silicone skeleton to the compound not having a silicone skeleton is preferably in the range of 15:85 to 85:15 by mass. More preferably, it is in the range of 30:70 to 70:30. By setting it in this range, phase separation between the low refractive index region and the high refractive index region is more likely to proceed, and the columnar region is more likely to tilt. If the ratio of the photopolymerizable compound having a silicone skeleton is less than the lower limit or more than the upper limit, phase separation is less likely to proceed, and the columnar region is less likely to tilt.

When silicone urethane (meth)acrylate is used as a photopolymerizable compound with a silicone skeleton, it has improved compatibility with compounds that do not have a silicone skeleton. This allows the columnar regions to be inclined even when the material mixing ratio is wide.

When preparing a composition containing a photopolymerizable compound, for example, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, xylene, etc. can be used as a solvent.

<<Manufacturing process>>
Next, a manufacturing process for the anisotropic light-diffusing film will be described.

First, a composition containing the above-mentioned photopolymerizable compound (hereinafter sometimes referred to as "photocurable resin composition") is applied to a suitable substrate such as a transparent PET film to form a sheet, which is then formed into a film to provide a photocurable resin composition layer. This photocurable resin composition layer is dried as necessary to volatilize the solvent, and the photocurable resin composition layer is then irradiated with light to produce an anisotropic light-diffusing film.

More specifically, the process for forming the anisotropic light-diffusing film mainly includes the following steps.
(1) Step 1-1: A step of providing an uncured resin composition layer on a substrate (2) Step 1-2: A step of obtaining a parallel light beam from a light source (3) Optional Step 1-3: A step of obtaining a directional light beam (4) Step 1-4: A step of curing the uncured resin composition layer

<Step 1-1: Step of Providing Uncured Resin Composition Layer on Substrate>
The photocurable resin composition is provided on the substrate in the form of a sheet as an uncured resin composition layer by a normal coating method or printing method.Specifically, coating such as 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, die coating, intaglio printing such as gravure printing, stencil printing such as screen printing, etc. can be used.When the composition has a low viscosity, a dam of a certain height can be provided around the substrate, and the composition can be cast into the area surrounded by the dam.

In step 1-1, in order to prevent oxygen inhibition of the uncured resin composition layer and efficiently form the columnar regions that are characteristic of anisotropic light-diffusing films, it is also possible to laminate a mask that adheres closely to the light-irradiated side of the uncured resin composition layer and locally changes the light irradiation intensity.

The mask material is preferably one in which light-absorbing fillers such as carbon are dispersed in a matrix, so that part of the incident light is absorbed by the carbon, but the openings allow sufficient light to pass through. Such matrices may be transparent plastics such as PET, TAC, PVAc, PVA, acrylic, and polyethylene, inorganic materials such as glass and quartz, or sheets containing these matrices with patterning to control the amount of UV light transmitted or pigments that absorb UV light.

When such a mask is not used, it is also possible to prevent oxygen inhibition of the uncured resin composition layer by performing light irradiation under a nitrogen atmosphere. In addition, simply laminating a normal transparent film on the uncured resin composition layer is also effective in preventing oxygen inhibition and promoting the formation of columnar regions. When light is irradiated through such a mask or transparent film, a photopolymerization reaction occurs in the composition containing the photopolymerizable compound according to the irradiation intensity, which makes it easy to generate a refractive index distribution, and is effective in producing the anisotropic light-diffusing film of this embodiment.

<Step 1-2: Step of obtaining parallel light from a light source>
As the light source, a short-arc ultraviolet light source is usually used, and specifically, a high-pressure mercury lamp, a low-pressure mercury lamp, a metahalide lamp, a xenon lamp, etc., can be used. At this time, it is necessary to obtain a light beam parallel to the desired scattering central axis, and such a parallel light beam can be obtained, for example, by arranging a point light source and arranging an optical lens such as a Fresnel lens for irradiating a parallel light beam between the point light source and the uncured resin composition layer, or by arranging a reflecting mirror behind the light source so that light is emitted as a point light source in a predetermined direction.

<Optional step 1-3: Step of obtaining a directional light beam>
Optional step 1-3 is a step of making parallel light incident on a directional diffusion element to obtain a directional light beam. Fig. 7 is a schematic diagram showing a method for producing an anisotropic light-diffusing film according to the present invention, including optional step 1-3.

The directional diffusion elements 301 and 302 used in optional steps 1-3 may be any element capable of imparting directionality to the parallel light beam D incident from the light source 300.

Figure 7 shows that directional light E is incident on the uncured resin composition layer 303 in a manner that it is largely diffused in the X direction and hardly diffused in the Y direction. In order to obtain such directional light, for example, a method can be adopted in which needle-shaped fillers with a high aspect ratio are contained in the directional diffusion elements 301 and 302 and the needle-shaped fillers are oriented so that their major axis direction extends in the Y direction. Various methods can be used for the directional diffusion elements 301 and 302 in addition to the method of using needle-shaped fillers.

Here, the aspect ratio of the directional light E is preferably 2 to 20. A columnar region having an aspect ratio roughly corresponding to the aspect ratio is formed. The upper limit of the aspect ratio is more preferably 10 or less, and even more preferably 5 or less. If the aspect ratio exceeds 20, there is a risk of interference rainbows and glare.

In optional step 1-3, the size (aspect ratio, short diameter SA, long diameter LA, etc.) of the columnar region formed can be appropriately determined by adjusting the spread of the directional light E. For example, the anisotropic light diffusion film of this embodiment can be obtained in either Figure 7 (a) or (b). The difference between Figure 7 (a) and (b) is that the spread of the directional light E is large in (a) but small in (b). The size of the columnar region differs depending on the size of the spread of the directional light E.

The spread of the directional light E depends mainly on the type of directional diffusion elements 301 and 302 and the distance from the uncured resin composition layer 303. As the distance is shortened, the size of the columnar region becomes smaller, and as the distance is lengthened, the size of the columnar region becomes larger. Therefore, the size of the columnar region can be adjusted by adjusting the distance.

<Step 1-4: Step of curing the uncured resin composition layer>
The light irradiated to the uncured resin composition layer to cure the uncured resin composition layer must contain a wavelength capable of curing the photopolymerizable compound, and light with a wavelength centered at 365 nm from a mercury lamp is usually used. When using this wavelength band to produce an anisotropic light-diffusing film, the illuminance is preferably in the range of 0.01 mW/cm ² to 100 mW/cm ² , and more preferably 0.1 mW/cm ² to 20 mW/cm ^2. If the illuminance is less than 0.01 mW/cm ² , it takes a long time to cure, resulting in poor production efficiency, and if it exceeds 100 mW/cm ² , the curing of the photopolymerizable compound is too fast to form a structure, making it impossible to express the desired optical properties.

The light irradiation time is not particularly limited, but is preferably 10 to 180 seconds, and more preferably 30 to 120 seconds. By irradiating the light beam, the anisotropic light diffusion film of this embodiment can be obtained.

As described above, the anisotropic light diffusion film is obtained by forming a specific internal structure in the uncured resin composition layer by irradiating low-intensity light for a relatively long time. Therefore, such light irradiation alone may leave unreacted monomer components, causing stickiness and problems in handling and durability. In such cases, the remaining monomers can be polymerized by additionally irradiating high-intensity light of 1000 mW/cm2 or ^more . The light irradiation at this time may be performed from the opposite side to the side where the mask is laminated.

As described above, when curing the uncured resin composition layer, the scattering central axis of the resulting anisotropic light-diffusing film can be adjusted to the desired value by adjusting the angle of light irradiated onto the uncured resin composition layer. In addition, the uncured resin composition layer is preferably adjusted to a temperature in the range of 30°C to 100°C.

<<<<<Applications of anisotropic light diffusion film>>>>
The anisotropic light-diffusing film has an excellent effect of improving the viewing angle dependency, and therefore can be applied to all kinds of display devices such as liquid crystal display devices, organic EL display devices, plasma displays, etc. The anisotropic light-diffusing film can be particularly preferably used in TN type liquid crystal displays, which are prone to problems with viewing angle dependency.

Here, according to the present invention, it is possible to provide a liquid crystal display device including a liquid crystal layer and an anisotropic light diffusion film. In this case, the anisotropic light diffusion film is provided on the viewing side of the liquid crystal layer. The liquid crystal display device may be any of the TN type, VA type, IPS type, etc. More specifically, a general liquid crystal device has a layer structure in which a light source, a polarizing plate, a glass substrate with a transparent electrode, a liquid crystal layer, a glass substrate with a transparent electrode, a color filter, and a polarizing plate are laminated in this order from the display device toward the viewing side, and further has an appropriate functional layer, but the anisotropic light diffusion film may be provided at any location on the viewing side of the liquid crystal layer.

According to the present invention, it is also possible to provide an organic EL display device including a light-emitting layer and an anisotropic light-diffusing film. In this case, the anisotropic light-diffusing film is provided (laminated) on the viewing side of the light-emitting layer (including the electrode connected to the light-emitting layer). The organic EL display device may be of either a top emission type or a bottom emission type, and in the case of a color organic EL display device, it may be of either an RGB color-separated type or a color filter type. The organic EL display may also be further multi-layered.

<<<<Example>>>
EXAMPLES Next, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples in any way.

<Anisotropic Optical Film>
A partition wall having a height of 40 to 60 μm was formed with a curable resin using a dispenser around the entire edge of a 100 μm thick PET film (manufactured by Toyobo Co., Ltd., product name: A4300). The following ultraviolet curable resin composition was dropped into this, and it was covered with another PET film.

Silicone urethane acrylate (refractive index: 1.460, weight average molecular weight: 5890) 20 parts by weight (manufactured by RAHN, product name: 00-225/TM18)
Neopentyl glycol diacrylate (refractive index: 1.450) 30 parts by weight (manufactured by Daicel Cytec Co., Ltd., product name Ebecryl 145)
Bisphenol A EO adduct diacrylate (refractive index: 1.536) 15 parts by weight (manufactured by Daicel Cytec Co., Ltd., product name Ebecryl 150)
Phenoxyethyl acrylate (refractive index 1.518) 40 parts by weight (manufactured by Kyoeisha Chemical, product name: Light Acrylate PO-A)
2,2-dimethoxy-1,2-diphenylethan-1-one 4 parts by weight (manufactured by BASF, product name: Irgacure 651)

The liquid film having a thickness of 40 to 60 μm, sandwiched between PET films on both sides, was irradiated with ultraviolet light in the form of parallel rays with an irradiation intensity of 10 to 100 mW/ ^cm2 from an epi-illumination unit of a UV spot light source (manufactured by Hamamatsu Photonics KK, product name: L2859-01). By changing parameters such as the irradiation angle, thickness of the liquid film, UV illuminance, and liquid film temperature during irradiation with parallel rays, anisotropic light-diffusing films 1 to 5 of the examples and anisotropic light-diffusing films 6 to 10 of the comparative examples having the optical properties shown in Table 1 were obtained.

<Measurement of thickness of anisotropic light-diffusing film>
A cross section was formed using a microtome on the anisotropic light-diffusing film obtained in the examples, and the cross section was then observed under an optical microscope to measure the thickness at 10 points. The average of these measurements was taken as the thickness of the anisotropic light-diffusing film.

<Measurement of Scattering Axis Angle and Linear Transmittance of Anisotropic Light Diffusion Film>
As shown in FIG. 6, a variable angle photometer (manufactured by Genesia) capable of arbitrarily varying the projection angle of the light source and the receiving angle of the detector was used to measure the linear transmittance of the anisotropic light diffusion film of the embodiment shown in Table 1 (including the linear transmittance at an incident angle of 60°). The detector was fixed at a position receiving the straight light from the light source, and the anisotropic light diffusion film obtained in the embodiment was set on the sample holder between them. As shown in FIG. 6, the sample was rotated around the rotation axis (V) to measure the linear transmittance corresponding to each incident light angle. This evaluation method makes it possible to evaluate the range of angles at which the incident light is diffused. This rotation axis (V) is a line on the anisotropic light diffusion film perpendicular to the tilt direction of the scattering central axis. The linear transmittance was measured at wavelengths in the visible light region using a visibility filter. Based on the optical profile obtained as a result of the above measurements, the maximum value (maximum linear transmittance) and minimum value (minimum linear transmittance) of the linear transmittance, as well as the angle of the scattering central axis at the approximate center between the minimum values in the optical profile (the center of the diffusion region) were determined, and are summarized in Table 1.

<Measurement of diffuse transmittance in the direction of a polar angle of 60° in the tilt direction of the scattering central axis for light with an incident angle of 0°>
Using a variable angle photometer goniophotometer (manufactured by Genesia), the diffuse transmittance of the light with an incidence angle of 0° of the anisotropic light diffusion film of the example shown in Table 1 in the direction of a polar angle of 60° in the tilt direction of the scattering central axis was measured. Specifically, the anisotropic optical film obtained in the example was set in a sample holder, a light source was placed in the normal direction (incidence angle = 0°) of one surface of the anisotropic light diffusion film, and a detector was placed on the other surface. The normal direction on the detector side was set to a polar angle θ = 0°, and the luminance was measured while varying the polar angle of the detector. The diffuse transmittance was a relative value with the luminance in the normal direction (polar angle θ = 0°) when no anisotropic light diffusion film was used as 100%. The obtained diffuse transmittance is shown in Table 1.

<Measurement of the aspect ratio of columnar structures (surface observation of anisotropic light-diffusing film)>
The cross section perpendicular to the column axis of the anisotropic light-diffusing film obtained in the examples (the side irradiated with ultraviolet light) was observed with an optical microscope, and the major axis LA and minor axis SA of the columnar structures in the columnar region were measured. The average major axis LA and the average minor axis SA were calculated as average values of 20 arbitrary structures. In addition, the average major axis LA/average minor axis SA was calculated as an aspect ratio for the average major axis LA and the average minor axis SA, and the ratio is summarized in Table 1.

<Measurement of Haze of Anisotropic Light Diffusion Film>
The haze of the anisotropic light-diffusing films obtained in the examples was measured using a haze meter NDH-2000 (manufactured by Nippon Denshoku Industries Co., Ltd.). The results are summarized in Table 1.

<<Evaluation method>>
The anisotropic light-diffusing films prepared in the above Examples 1 to 5 and Comparative Examples 1 to 5 were evaluated as follows.

<Evaluation of tone inversion>
The anisotropic light-diffusing film was attached to the surface of a TN mode liquid crystal display such that the angle between the direction in which tone inversion occurs in the liquid crystal display and the tilt direction of the scattering central axis of the anisotropic light-diffusing film a was 0°.
Next, a viewing angle measuring device Conometer 80 (manufactured by Westboro) was used to measure the luminance distribution in the polar angle range of 0 to 80° relative to the normal direction of the display when a gray scale divided into 11 gradations from white to black was displayed on the display.
The "white luminance/black luminance" was calculated at a polar angle of 80° in the direction in which grayscale inversion occurs in the liquid crystal display alone, and this was taken as the contrast. In addition, in the direction in which grayscale inversion occurs in the liquid crystal display alone, the minimum polar angle at which the measured 11 grayscales are reversed from the original grayscale was taken as the grayscale inversion angle. This is summarized in Table 2.
Here, in an evaluation of the display alone, without the anisotropic light-diffusing film attached, the contrast was 8.0 and the tone inversion angle was 28°.

<Criteria for determining tone inversion>
The tone inversion angle of 65° or more was rated as ⊚, that of 52° or more and less than 65° was rated as ◯, and that of less than 52° was rated as x.

<Contrast evaluation criteria at 80° polar angle>
A contrast of 11 or more was rated as ⊚, a contrast of 9 or more but less than 11 was rated as ◯, and a contrast of less than 9 was rated as x.

<<Evaluation Results>>
As shown in Examples 1 to 5, the effect of improving tone inversion and the contrast at 80° of the present invention using a predetermined anisotropic light-diffusing film are superior to those of Comparative Examples 1 to 5.
In Comparative Examples 1 and 3, the linear transmittance is high at an incident angle of 60°, and the diffuse transmittance in the polar angle 60° direction in the tilt azimuth of the scattering central axis for light at an incident angle of 0° is also low, so that the light in the 60° direction where the grayscale-inverted light is emitted cannot be diffused, and the light in the 0° direction with the correct grayscale cannot be diffused to angles with a large polar angle. In Comparative Example 2, the diffuse transmittance is sufficient, but the linear transmittance is insufficient, and conversely, in Comparative Examples 4 and 5, the linear transmittance is sufficient, but the diffuse transmittance is insufficient, so that both have small grayscale inversion angles.

It is believed that the present invention was able to obtain these evaluation results by using a specific anisotropic light diffusion film as a diffusion medium with specific diffusion characteristics.

Therefore, when the light diffusion film of the embodiment is used in, for example, a TN liquid crystal display device, it is possible to suppress gray scale inversion and improve contrast at deep angles, thereby ensuring visibility even in directions where visibility is normally difficult.

Claims (6)

An anisotropic light-diffusing film having a linear transmittance, which is (amount of transmitted light in a linear direction of incident light)/(amount of incident light), that changes depending on the angle of incidence of light,
the anisotropic light-diffusing film has a matrix region and a plurality of columnar regions having a refractive index different from that of the matrix region;
Furthermore, the anisotropic light-diffusing film has one scattering central axis,
In the tilt direction of the scattering central axis,
The linear transmittance at an incident angle of 60° is 10% or less,
The diffuse transmittance of light at an incident angle of 0° in a polar angle direction of 60° is 0.001% or more,
1. An anisotropic light-diffusing film, characterized in that the haze value of the anisotropic light-diffusing film is 75% or more . If the polar angle between the surface normal direction of the anisotropic light-diffusing film and the scattering central axis direction is defined as the scattering central axis angle,
2. The anisotropic light-diffusing film according to claim 1, wherein the scattering central axis angle of the anisotropic light-diffusing film is 20° to 60°. 3. The anisotropic light-diffusing film according to claim 1 , wherein the thickness of the anisotropic light-diffusing film is 15 μm to 100 μm. The plurality of columnar regions of the anisotropic light-diffusing film are
The anisotropic light diffusing film is oriented and extends from one surface to the other surface,
The anisotropic light-diffusing film according to any one of claims 1 to 3, characterized in that the aspect ratio of the columnar regions, which is the average long axis/average short axis of the columnar regions in a cross section perpendicular to the column axis of the anisotropic light-diffusing film, is less than 2 . A liquid crystal display device, comprising: an anisotropic light-diffusing film according to any one of claims 1 to 4 laminated on a viewing side of a liquid crystal layer. 5. An organic electroluminescence display device, comprising: an anisotropic light-diffusing film according to claim 1 laminated on a viewing side of a light-emitting layer.

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