JP7343024B1 - An optical film, a polarizing plate, a surface plate, an image display panel, and an image display device using the optical film, a method for manufacturing the optical film, a method for selecting an optical film, and a method for evaluating fingerprint wiping performance. - Google Patents

Abstract

An object of the present invention is to provide an optical film that has excellent anti-glare properties and good fingerprint wiping properties. An optical film having a first surface and a second surface opposite to the first surface, wherein the optical film is arranged such that the optical film extends from the first surface toward the second surface. The first surface has an anti-reflection layer and an anti-glare layer in this order, the first surface has an uneven shape, and the first surface has a protruding valley space volume Vvv of 0 as defined in ISO 25178-2:2012. .005 ml/m2 or more, and a falling contact angle measured by the method described below is 30.0 degrees or more. <Measurement of falling contact angle> A droplet having a surface tension of 30 mN/m is dropped from a height of 45 mm onto the first surface of the optical film. The droplet is caused to fall from a direction perpendicular to the first surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method. [Selection diagram] Figure 1

Description

The present disclosure relates to an optical film, a polarizing plate, a surface plate, an image display panel, and an image display device using the optical film, a method for manufacturing the optical film, a method for selecting an optical film, and a fingerprint wiping method. Concerning gender evaluation methods.

Optical films are installed on the surfaces of image display devices such as televisions, notebook PCs, and desktop PC monitors in order to suppress reflections of backgrounds such as lighting and people, and to suppress reflections on the surface. There are cases.
As optical films, for example, Patent Documents 1 to 3 have been proposed.

International Publication No. 2019/026466 International Publication No. 2019/026471 JP 2019-85473 Publication

The optical films of Patent Documents 1 and 2 are anti-glare films that have an anti-glare layer with an uneven surface. An optical film having an uneven surface has a tendency for fingerprint wiping properties to deteriorate due to fingerprints getting into the uneven surface. As for the anti-glare film, the better the anti-glare property is, the more likely the fingerprint wiping property is to be reduced. The optical films of Patent Documents 1 and 2 do not have any study on antifouling properties.

The optical film of Patent Document 3 is a coated film in which the sliding angle of oleic acid is 32° or less. Although the coated film of Patent Document 3 aims to make fingerprints easy to wipe off, it cannot be said that the fingerprint wiping properties are good.
If the fingerprints attached to the optical film are not wiped off sufficiently, the appearance of the optical film will deteriorate due to the contrast in optical properties between areas that have fingerprint components and areas that do not have fingerprint components. Particularly, in the case of an optical film having an antireflection layer, the contrast in reflectance between a portion having a fingerprint component and a portion not having a fingerprint component becomes large, and the appearance of the optical film is greatly deteriorated.

An object of the present disclosure is to provide an optical film having an uneven surface and an antireflection layer on the surface, which has excellent anti-glare properties and good fingerprint wiping properties. An object of the present disclosure is to provide a polarizing plate, a surface plate, an image display panel, and an image display device that have excellent anti-glare properties and good fingerprint wiping properties. An object of the present disclosure is to provide a method for manufacturing an optical film that has excellent anti-glare properties and good fingerprint wiping properties. An object of the present disclosure is to provide a method for selecting an optical film that has excellent anti-glare properties and good fingerprint wiping properties. An object of the present disclosure is to provide an evaluation method that can easily evaluate fingerprint wiping performance.

The present disclosure provides the following [1] to [8].
[1] An optical film having a first surface and a second surface opposite to the first surface,
The optical film has an antireflection layer and an antiglare layer in this order from the first surface to the second surface,
the first surface has an uneven shape;
The first surface has a protruding valley space volume Vvv defined in ISO 25178-2:2012 of 0.005 ml/m ² or more,
An optical film having a falling contact angle of 30.0 degrees or more as measured by the method below.
<Measurement of falling contact angle>
A droplet having a surface tension of 30 mN/m is dropped from a height of 45 mm onto the first surface of the optical film. The droplet is caused to fall from a direction perpendicular to the first surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method.
[2] A polarizing plate comprising a polarizer, a first transparent protective plate disposed on one side of the polarizer, and a second transparent protective plate disposed on the other side of the polarizer. hand,
At least one of the first transparent protection plate and the second transparent protection plate is the optical film according to [1], and the second surface of the optical film and the polarizer are arranged to face each other. Also, a polarizing plate.
[3] A surface plate for an image display device in which a protective film is laminated onto a resin plate or a glass plate, wherein the protective film is the optical film according to [1], and the second surface of the optical film and the resin plate or the glass plate are arranged to face each other.
[4] An image display panel having a display element and an optical film disposed on the light exit surface side of the display element, the image display panel including the optical film according to [1] as the optical film.
[5] An image display device including the image display panel according to [4].
[6] A method for producing the optical film according to [1], comprising:
An optical film manufacturing method comprising a first step of forming an anti-glare layer on a base material and a second step of forming an anti-reflection layer on the anti-glare layer.
[7] An optical film selection method that selects an optical film that satisfies the following selection conditions.
(Selection conditions for optical film)
An optical film having a first surface and a second surface opposite to the first surface,
The optical film has an antireflection layer and an antiglare layer in this order from the first surface to the second surface,
the first surface has an uneven shape;
The first surface has a protruding valley space volume Vvv defined in ISO 25178-2:2012 of 0.005 ml/m ² or more,
The falling contact angle measured by the method below is 30.0 degrees or more.
<Measurement of falling contact angle>
A droplet having a surface tension of 30 mN/m is dropped from a height of 45 mm onto the first surface of the optical film. The droplet is caused to fall from a direction perpendicular to the first surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method.
[8] A method for evaluating fingerprint wiping performance, using the value of the falling contact angle measured by the following method as an evaluation index.
<Measurement of falling contact angle>
A droplet with a surface tension of 30 mN/m is dropped from a height of 45 mm onto the surface of the object to be measured. The droplet is caused to fall from a direction perpendicular to the surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method.

The optical film, polarizing plate, surface plate, image display panel, and image display device of the present disclosure have excellent anti-glare properties and can have good fingerprint wiping properties. The method for producing an optical film of the present disclosure can easily produce an optical film that has excellent anti-glare properties and good fingerprint wiping properties. The method for selecting an optical film of the present disclosure can efficiently select an optical film that has excellent anti-glare properties and good fingerprint wiping properties. The fingerprint wiping property evaluation method of the present disclosure can easily evaluate the fingerprint wiping property of a measurement target.

1 is a schematic cross-sectional view showing an embodiment of an optical film of the present disclosure. FIG. 1 is a cross-sectional view showing an embodiment of an image display panel of the present disclosure.

Embodiments of the present disclosure will be described below.
[Optical film]
The optical film of the present disclosure is as follows.
An optical film having a first surface and a second surface opposite to the first surface,
The optical film has an antireflection layer and an antiglare layer in this order from the first surface to the second surface,
the first surface has an uneven shape;
The first surface has a protruding valley space volume Vvv defined in ISO 25178-2:2012 of 0.005 ml/m ² or more,
An optical film having a falling contact angle of 30.0 degrees or more as measured by the method below.
<Measurement of falling contact angle>
A droplet having a surface tension of 30 mN/m is dropped from a height of 45 mm onto the first surface of the optical film. The droplet is caused to fall from a direction perpendicular to the first surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method.

FIG. 1 is a schematic cross-sectional view of the cross-sectional shape of an optical film 100 of the present disclosure.
The optical film 100 of FIG. 1 has a first surface having an uneven shape and a second surface that is a surface opposite to the first surface. In FIG. 1, the upper surface is the first surface, and the lower surface is the second surface.
The optical film of FIG. 1 has an antireflection layer 30, an antiglare layer 20, and a base material 10 in this order from the first surface to the second surface.
FIG. 1 is a schematic cross-sectional view. That is, the scale of each layer constituting the optical film 100 and the scale of the uneven shape are simplified for ease of illustration, and are different from the actual scale. The same applies to FIGS. 2 and 3.

The optical film of the present disclosure is not limited to the laminated structure shown in FIG. For example, the optical film of the present disclosure may have a laminated structure without a base material. The optical film of the present disclosure may have layers other than the base material, antiglare layer, and antireflection layer.

<Side 1>
The optical film of the present disclosure has a first surface. In the optical film of the present disclosure, it is preferable that the surface of the antireflection layer is the first surface.

The first surface of the optical film has an uneven shape, and the protruding valley space volume Vvv defined in ISO 25178-2:2012 is 0.005 ml/m ² or more. If the first surface does not have an uneven shape, the optical film cannot have good anti-glare properties. Even if the first surface has an uneven shape, if Vvv is less than 0.005 ml/m ² , the optical film cannot have good anti-glare properties.

Vvv is preferably 0.007 ml/m ² or more, more preferably 0.010 ml/m ² or more, more preferably 0.020 ml/m ² or more, and 0.030 ml/m ² It is more preferable that it is above.
If Vvv is too large, it tends to be difficult to increase the falling contact angle to 30.0 degrees or more. Therefore, Vvv is preferably 0.100 ml/m ² or less, more preferably 0.080 ml/m ² or less, more preferably 0.060 ml/m ² or less, and 0.045 ml/m 2 or less. /m ² or less is more preferable.

The embodiment of the range of Vvv on the first side is 0.005 ml/m ² or more and 0.100 ml/m ² or less, 0.005 ml/m ² or more and 0.080 ml/m ² or less, and 0.005 ml/m ² or more and 0. .060ml/ ^m2 or less, 0.005ml/ ^m2 or more and 0.045ml/ ^m2 or less, 0.007ml/m2 or more and 0.100ml/ ^{m2 or} less, 0.007ml/ ^m2 or more and 0.080ml/ ^m2 Below, 0.007ml/ ^m2 or more and 0.060ml/ ^m2 or less, 0.007ml/ ^m2 or more and 0.045ml/ ^m2 or less, 0.010ml/ ^m2 or more and 0.100ml/ ^m2 or less, 0.010ml / ^m2 or more and 0.080ml/ ^m2 or less, 0.010ml/ ^m2 or more and 0.060ml/m2 or less, 0.010ml/ ^m2 or more and 0.045ml/ ^{m2 or} less, 0.020ml/m2 ^or more and 0 .100ml/ ^m2 or less, 0.020ml/ ^m2 or more and 0.080ml/ ^m2 or less, 0.020ml/m2 or more and 0.060ml/ ^{m2 or} less, 0.020ml/ ^m2 or more and 0.045ml/ ^m2 Below, 0.030ml/ ^m2 or more and 0.100ml/ ^m2 or less, 0.030ml/ ^m2 or more and 0.080ml/ ^m2 or less, 0.030ml/ ^m2 or more and 0.060ml/ ^m2 or less, 0.030ml / ^m2 or more and 0.045ml/ ^m2 or less.

The first surface of the optical film has a falling contact angle of 30.0 degrees or more as measured by the method described below.
<Measurement of falling contact angle>
A droplet having a surface tension of 30 mN/m is dropped from a height of 45 mm onto the first surface of the optical film. The droplet is caused to fall from a direction perpendicular to the first surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method.

When the falling contact angle of the first surface is less than 30.0 degrees, good fingerprint wiping performance cannot be achieved. The relationship between the falling contact angle and the fingerprint wiping property will be explained below.
In the falling contact angle measurement of the present disclosure, a droplet is dropped from a height of 45 mm onto the first surface of the optical film. Since the droplet that has fallen onto the first surface has a crushed shape due to the impact upon falling, the contact angle of the droplet immediately after falling tends to be small. In particular, in the case of an optical film having an uneven shape with a Vvv of a predetermined value or more, the droplet easily wets and spreads, so the contact angle of the droplet immediately after falling tends to be small.
Liquid present in a collapsed shape on the first surface of the optical film is difficult to wipe off. In the falling contact angle measurement of the present disclosure, the static contact angle 10 seconds after the droplet has been deposited is measured by the θ/2 method. The optical film of the present disclosure has a falling contact angle of 30.0 degrees or more. That is, in the optical film of the present disclosure having a falling contact angle of 30.0 degrees or more, this means that droplets that have been crushed due to impact upon falling recover to a nearly spherical shape. Therefore, the optical film of the present disclosure can have good fingerprint wiping properties even though it has an uneven shape with a Vvv of 0.005 ml/m ² or more.

When you touch the surface of an optical film with your finger, the pressure of the touch causes the fingerprint components to penetrate into the concavo-convex shape. In the falling contact angle measurement of the present disclosure, the reason why the droplet is dropped from a height of 45 mm is to take into consideration the above-mentioned phenomenon (the phenomenon in which fingerprint components penetrate into the inside of the uneven shape due to pressure).
In the falling contact angle measurement, the amount of droplets dropped is preferably 5.0 μl.

Fingerprints contain not only water but also sebum and the like. Therefore, in the falling contact angle measurement of the present disclosure, a liquid with a surface tension of 30 mN/m is used instead of pure water. In this specification, a liquid having the following composition was used as the liquid having a surface tension of 30 mN/m. In this specification, surface tension means a value measured by a Wilhelmy surface tension meter specified in JIS K2241:2017.
<Composition of liquid with surface tension of 30 mN/m>
A liquid containing 100% by mass of ethylene glycol monoethyl ether.

The falling contact angle is preferably 40.0 degrees or more, more preferably 45.0 degrees or more, and even more preferably 50.0 degrees or more.
If the falling contact angle is too large, the content of fluorine-based compounds and silicone-based compounds in the antireflection layer increases, and the scratch resistance of the optical film tends to decrease. Therefore, the falling contact angle is preferably 70.0 degrees or less, more preferably 60.0 degrees or less, and even more preferably 55.0 degrees or less.

The falling contact angle range of the first surface is 30.0 degrees or more and 70.0 degrees or less, 30.0 degrees or more and 60.0 degrees or less, 30.0 degrees or more and 55.0 degrees or less, and 40. 0 degrees or more and 70.0 degrees or less, 40.0 degrees or more and 60.0 degrees or less, 40.0 degrees or more and 55.0 degrees or less, 45.0 degrees or more and 70.0 degrees or less, 45.0 degrees or more and 60.0 degrees degree or less, 45.0 degrees or more and 55.0 degrees or less, 50.0 degrees or more and 70.0 degrees or less, 50.0 degrees or more and 60.0 degrees or less, and 50.0 degrees or more and 55.0 degrees or less.

In this specification, Vvv, Vvc, and Vmp are calculated assuming that the load area ratio separating the core part and the protruding peak part is 10%, and the load area ratio separating the core part and the protruding valley part is 80%. .
In this specification, Sxp means the difference between the height at a load area ratio of 2.5% and the height at a load area ratio of 50%.

In this specification, surface shapes such as Vvv, Vvc, Vmp, Sxp, and Sal are preferably measured using a confocal laser microscope. Examples of confocal laser microscopes include the "VK-X" series manufactured by Keyence Corporation. Further, by using the "multi-file analysis application" of the "VK-X" series described above, Vvv, Vvc, Vmp, Sxp, and Sal can be easily calculated.
The measurement conditions when measuring Vvv, Vvc, Vmp, Sxp, and Sal using the aforementioned "VK-X" series are preferably in accordance with the conditions described in Examples. For example, it is preferable that the F-operation is plane tilt correction (area specification). The measurement area is preferably a rectangle with one side of 50 μm or more and 200 μm or less, and the number of measurement points is preferably 500 or more and 2000 or less per side.

In this specification, surface shape (Vvv, Vvc, Vmp, Sxp and Sal), contact angle (falling contact angle, pure water contact angle), elemental ratio (F/inorganic Si, organic Si/inorganic Si, F/organic Si, etc.), optical properties ( _RSCI , haze, total light transmittance, transmitted image clarity, etc.) are based on the 14 measured values excluding the maximum and minimum values from the 16 measured values, unless otherwise specified. Means the average value.
In this specification, the 16 measurement points are the 16 points of intersection when a 1 cm area from the outer edge of the measurement sample is removed as a margin, and a line dividing the remaining area into 5 equal parts in the vertical and horizontal directions is drawn. It is preferable to center the measurement on For example, if the measurement sample is a rectangle, a 0.5 cm area from the outer edge of the rectangle is removed as a margin, and the remaining area is divided into 5 equal parts in the vertical and horizontal directions, and measurements are performed centering on 16 points of intersection of dotted lines. Preferably, the average value of 14 measured values obtained by removing the maximum value and minimum value from the measured values at 16 locations is set as the value of the parameter. When the measurement sample has a shape other than a rectangle, such as a circle, an ellipse, a triangle, or a pentagon, it is preferable to draw a rectangle inscribed in these shapes and perform measurements at 16 locations on the rectangle using the above method.

In this specification, surface shape (Vvv, Vvc, Vmp, Sxp and Sal), contact angle (falling contact angle, pure water contact angle), surface tension, element ratio (F/inorganic Si, organic Si/inorganic Si, F/organic Si, etc.), optical properties ( _RSCI , haze, total light transmittance, transmitted image clarity, etc.) are measured at a temperature of 23 ± 5°C and a relative humidity of 40% to 65%, unless otherwise specified. It shall be assumed that Furthermore, before starting each measurement, the target sample is exposed to the atmosphere for 30 minutes or more and 60 minutes or less, and then the measurement is performed.
In the optical film of the present disclosure, the pure water contact angle on the first surface is preferably 100 degrees or more and 120 degrees or less, more preferably 110 degrees or more and 115 degrees or less.
The contact angle of pure water can be determined by dropping 1.0 μL of pure water on the first surface side and measuring the static contact angle 10 seconds after the droplet has landed according to the θ/2 method.

The first surface of the optical film of the present disclosure preferably has a ratio (Vvv/Vvc) of 0.10 or less between Vvv and Vvc, which is the core space volume defined in ISO 25178-2:2012. . By setting Vvv/Vvc to 0.10 or less, the fingerprint wiping property can be easily improved. Vvv/Vvc is more preferably 0.09 or less, and even more preferably 0.08 or less.

The first surface of the optical film of the present disclosure preferably has a protruding mountain substantial volume Vmp defined in ISO 25178-2:2012 of 0.005 ml/m ² or more and 0.100 ml/m ² or less.
By setting the Vmp of the first surface to 0.005 ml/m ² or more, good anti-glare properties can be easily achieved. Vmp is more preferably 0.007 ml/m ² or more, more preferably 0.010 ml/m ² or more, and even more preferably 0.020 ml/m ² or more.
By setting the Vmp of the first surface to 0.100 ml/m ² or less, the scratch resistance of the optical film can be easily improved. Vmp is more preferably 0.080 (ml/m ² ) or less, more preferably 0.060 (ml/m ² ) or less, and 0.045 (ml/m ² ) or less. is more preferable.

The first surface of the optical film of the present disclosure preferably has a minimum autocorrelation length Sal of 4.0 μm or more and 12.0 μm or less as defined in ISO 25178-2:2012.

Sal is a parameter focused on the horizontal direction. As Sal is smaller, the first surface has a shape in which the unevenness is densely packed, and as Sal is larger, the first surface has a shape in which the intervals between the unevenness are wide. The value of "average length RSm of roughness curve elements" specified in JIS B0601 is hardly affected by minute irregularities, and only by large irregularities. On the other hand, the value of Sal is different from RSm in that it is affected not only by large irregularities but also by minute irregularities. Further, even if the interval between the concavo-convex portions is wide, if the convex portions are small or the convex-concave shape is complex, Sal tends to become small. Further, if the convex portion has a monotonous shape, Sal tends to increase.

By setting Sal to 4.0 μm or more, the fingerprint wiping property can be easily improved. By setting Sal to 12.0 μm or less, antiglare properties can be easily improved.
The lower limit of Sal is more preferably 5.0 μm or more, and even more preferably 6.0 μm or more. The upper limit of Sal is more preferably 11.0 μm or less, and even more preferably 10.0 μm or less.
The range of Sal on the first surface is 4.0 μm or more and 12.0 μm or less, 4.0 μm or more and 11.0 μm or less, 4.0 μm or more and 10.0 μm or less, 5.0 μm or more and 12.0 μm or less, and 5. Examples include 0 μm to 11.0 μm, 5.0 μm to 10.0 μm, 6.0 μm to 12.0 μm, 6.0 μm to 11.0 μm, and 6.0 μm to 10.0 μm.

The first surface of the optical film of the present disclosure preferably has a pole height Sxp defined in ISO 25178-2:2012 of 0.15 μm or more and 2.00 μm or less.
Sxp is a parameter indicating the difference between the average surface of the uneven shape and the convex portion after removing particularly high protrusions from the uneven shape. By setting Sxp to 0.15 μm or more, anti-glare properties can be easily improved. By setting Sxp to 2.00 μm or less, fingerprint wiping performance can be easily improved.
The lower limit of Sxp is more preferably 0.20 μm or more, more preferably 0.25 μm or more, more preferably 0.50 μm or more, and more preferably 0.70 μm or more. The upper limit of Sxp is more preferably 1.80 μm or less, more preferably 1.50 μm or less, and even more preferably 1.40 μm or less.
In the embodiment, the Sxp range of the first surface is 0.15 μm or more and 2.00 μm or less, 0.15 μm or more and 1.80 μm or less, 0.15 μm or more and 1.50 μm or less, 0.15 μm or more and 1.40 μm or less, and 0. 20μm or more and 2.00μm or less, 0.20μm or more and 1.80μm or less, 0.20μm or more and 1.50μm or less, 0.20μm or more and 1.40μm or less, 0.25μm or more and 2.00μm or less, 0.25μm or more and 1.80μm Below, 0.25 μm to 1.50 μm, 0.25 μm to 1.40 μm, 0.50 μm to 2.00 μm, 0.50 μm to 1.80 μm, 0.50 μm to 1.50 μm, 0.50 μm Examples include 1.40 μm or more, 0.70 μm or more and 2.00 μm or less, 0.70 μm or more and 1.80 μm or less, 0.70 μm or more and 1.50 μm or less, and 0.70 μm or more and 1.40 μm or less.

In the optical film of the present disclosure, it is preferable that the element ratio obtained by analyzing the surface area on the first surface side by X-ray photoelectron spectroscopy satisfies the following formulas 2 to 4.
3.5≦F/Inorganic Si≦10.0 (Formula 2)
0.08≦Organic Si/Inorganic Si≦1.00 (Formula 3)
5.0≦F/Organic Si≦50.0 (Formula 4)
[In formulas 2 to 4, "F" is the ratio of the fluorine element, "inorganic Si" is the ratio of the silicon element belonging to the inorganic silicon compound, and "organic Si" is the ratio of the silicon element belonging to the organosilicon compound. It is a ratio. ]

In this specification, the "surface region on the first surface side" refers to a region from the surface on the first surface side to a depth of 10 nm. In this specification, "X-ray photoelectron spectroscopy" may be referred to as "XPS". The element ratio in the surface region on the first surface side can be measured, for example, by the method described in Examples.

In the surface region of the first side of the optical film, inorganic Si mainly originates from silica particles. In the surface region of the first side of the optical film, organic Si and F mainly originate from the leveling agent.
Inorganic Si and organic Si can be separated by peak-separating the inorganic and organic components from the X-ray photoelectron spectrum of the Si2p orbital.

In the surface region of the first surface of the optical film, inorganic Si can lower the refractive index of the first surface, but tends to deteriorate the fingerprint wiping property. Furthermore, by containing a predetermined amount or more of organic Si and F relative to inorganic Si in the surface region of the first surface of the optical film, fingerprint wiping properties tend to be improved. Furthermore, by containing organic Si and F in a well-balanced manner in the surface region of the first surface of the optical film, fingerprint wiping properties tend to be improved. Therefore, by setting F/inorganic Si to 3.5 or more, organic Si/inorganic Si to 0.08 or more, and F/organic Si to 5.0 or more and 50.0 or less, the falling contact angle can be increased. The temperature can be easily adjusted to 30.0 degrees or more, and the fingerprint wiping property can be easily improved.
Further, by setting F/inorganic Si to 10.0 or less and organic Si/inorganic Si to 1.00 or less, it is possible to easily suppress deterioration in coatability of the antireflection layer.

The lower limit of F/inorganic Si is more preferably 4.0 or more, even more preferably 4.5 or more, and the upper limit is more preferably 9.0 or less, and 8.0 or less. is even more preferable.
The lower limit of organic Si/inorganic Si is more preferably 0.10 or more, even more preferably 0.15 or more, and the upper limit is more preferably 0.80 or less, and 0.50 or less. It is even more preferable.
The lower limit of F/organic Si is more preferably 10.0 or more, even more preferably 15.0 or more, even more preferably 22.0 or more, and the upper limit is 40.0 or less. is more preferable, and even more preferably 35.0 or less.

Embodiments of the range of F/inorganic Si include 3.5 or more and 10.0 or less, 3.5 or more and 9.0 or less, 3.5 or more and 8.0 or less, 4.0 or more and 10.0 or less, and 4.0. Examples thereof include 9.0 or more, 4.0 or more and 8.0 or less, 4.5 or more and 10.0 or less, 4.5 or more and 9.0 or less, and 4.5 or more and 8.0 or less.
Embodiments of the range of organic Si/inorganic Si include 0.08 or more and 1.00 or less, 0.08 or more and 0.80 or less, 0.08 or more and 0.50 or less, 0.10 or more and 1.00 or less, and 0. Examples include 10 or more and 0.80 or less, 0.10 or more and 0.50 or less, 0.15 or more and 1.00 or less, 0.15 or more and 0.80 or less, and 0.15 or more and 0.50 or less.
Embodiments of the range of F/organic Si include 5.0 or more and 50.0 or less, 5.0 or more and 40.0 or less, 5.0 or more and 35.0 or less, 10.0 or more and 50.0 or less, and 10.0. 40.0 or more, 10.0 or more and 35.0 or less, 15.0 or more and 50.0 or more, 15.0 or more and 40.0 or more, 15.0 or more and 35.0 or less, 22.0 or more and 50.0 or less , 22.0 or more and 40.0 or less, and 22.0 or more and 35.0 or less.

In the optical film of the present disclosure, regarding the element ratio obtained by analyzing the surface area on the first surface side by X-ray photoelectron spectroscopy, the ratio of inorganic Si to all elements is 2 atomic % or more and 20 atomic % or less. preferable. By setting the proportion of inorganic Si to all elements to be 2 atomic % or more, the refractive index of the first surface can be easily lowered, so that the antireflection properties of the optical film can be easily improved. By setting the proportion of inorganic Si to 20 atomic % or less, F/inorganic Si can be easily made to be 3.5 or more and organic Si/inorganic Si to be 0.08 or more.
The lower limit of the ratio of inorganic Si to all elements is more preferably 3 atom% or more, even more preferably 4 atom% or more, and the upper limit is more preferably 15 atom% or less, 12 atom% or less. It is more preferable that
Embodiments of the range of the ratio of inorganic Si to all elements include 2 at% or more and 20 at% or less, 2 at% or more and 15 at% or less, 2 at% or more and 12 at% or less, 3 at% or more and 20 at% or less, Examples include 3 atom % to 15 atom %, 3 atom % to 12 atom %, 4 atom % to 20 atom %, 4 atom % to 15 atom %, and 4 atom % to 12 atom %.

<Laminated structure>
The optical film of the present disclosure has an antireflection layer and an antiglare layer in this order from the first surface to the second surface. It is preferable that the outermost surface of the optical film on the first surface side is an antireflection layer.
The optical film of the present disclosure may have layers other than the antireflection layer and the antiglare layer. Layers other than the antireflection layer and the antiglare layer include a base material, an antistatic layer, an adhesive layer, and the like.
The optical film of the present disclosure preferably has an antireflection layer, an antiglare layer, and a base material in this order from the first surface to the second surface.

"Base material"
The optical film preferably has a base material for ease of manufacture and ease of handling.

The base material is preferably one that has light transmittance, smoothness, heat resistance, and excellent mechanical strength. Such base materials include polyester, triacetylcellulose (TAC), cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyethersulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, Examples include plastic films such as polyetherketone, polymethyl methacrylate, polycarbonate, polyurethane, and amorphous olefin (Cyclo-Olefin-Polymer: COP). The base material may be made by laminating two or more plastic films together.
Among plastic films, stretched polyester films are preferred, and biaxially stretched polyester films are more preferred, for mechanical strength and dimensional stability. Examples of the polyester film include polyethylene terephthalate film and polyethylene naphthalate film. TAC film and acrylic film are suitable because they tend to have good light transmittance and optical isotropy. COP film and polyester film are suitable because they have excellent weather resistance.

The thickness of the base material is preferably 5 μm or more and 300 μm or less, more preferably 20 μm or more and 200 μm or less, and even more preferably 30 μm or more and 120 μm or less.
When it is desired to make the optical film thin, the preferable upper limit of the thickness of the base material is 100 μm or less, and the more preferable upper limit is 80 μm or less. Further, when the base material is a low moisture permeable base material such as polyester, COP, acrylic, etc., the preferable upper limit of the thickness of the base material for thinning is 60 μm or less, and the more preferable upper limit is 40 μm or less. Even in the case of a large screen, it is preferable that the upper limit of the thickness of the base material be within the above-mentioned range, since distortion can be made less likely to occur.
The thickness of the base material can be measured, for example, with a film thickness measuring device. Examples of the film thickness measuring device include Mitutoyo's Digimatic Standard Outside Micrometer (product number: MDC-25SX). The thickness of the base material may be as long as the average value measured at ten arbitrary points is the above value.

The total light transmittance of the base material according to JIS K7361-1:1997 is preferably 70% or more, more preferably 80% or more, and even more preferably 85% or more.
The haze of the base material according to JIS K7136:2000 is preferably 10% or less, more preferably 5% or less, and even more preferably 3% or less.

The surface of the base material may be subjected to physical treatment such as corona discharge treatment or chemical treatment to improve adhesiveness. Moreover, the base material may have an easily adhesive layer on the surface.

《Anti-glare layer》
The anti-glare layer is a layer that plays a central role in anti-glare properties.
The anti-glare layer can be formed, for example, by (A) a method using an embossing roll, (B) etching treatment, (C) molding with a mold, (D) forming a coating film by coating, and the like. In order to easily obtain a stable surface shape, molding using a mold (C) is preferable, and in order to increase productivity and support a wide variety of products, forming a coating film by coating (D) is preferable.

In the method (C), the anti-glare layer can be formed by, for example, pouring a resin into a mold and taking out the molded resin from the mold. The molded resin taken out from the mold may be placed on a base material. The mold used is one in which the surface shape of the anti-glare layer is reversed. Such a mold can be produced, for example, by the following methods (c1-1) to (c1-2) or (c2) below.
(c1-1) A shape in which Vvv etc. fall within a predetermined range is created by simulation. Furthermore, the simulated shape is inverted.
(c1-2) A mold is obtained by engraving the surface of the metal with a laser beam or processing the surface of the metal by photolithography so that the inverted shape is reflected.

(c2) A mold in which the shape of the anti-glare layer produced in (D) is reversed is obtained by a general-purpose electroforming method.

When forming an anti-glare layer using (D), for example, the following methods (d1) and (d2) may be used. (d1) is preferable to (d2) in that it is easier to adjust the range of surface shape such as Vvv.
(d1) A means for coating and drying a coating liquid containing a binder resin and particles to form an anti-glare layer having irregularities based on the particles.
(d2) Means for forming unevenness by applying a coating liquid containing an arbitrary resin and a resin having poor compatibility with the resin to cause phase separation of the resin.

-Thickness-
The thickness T of the anti-glare layer is preferably 2.0 μm or more and 10.0 μm or less, and preferably 3.0 μm or more and 8.0 μm or less, in order to balance curl suppression, mechanical strength, hardness, and toughness. More preferably, it is 4.0 μm or more and 6.0 μm or less.
The thickness of the anti-glare layer can be calculated, for example, by selecting 20 arbitrary points in a cross-sectional photograph of an optical film taken with a scanning transmission electron microscope and calculating the average value thereof. It is preferable that the accelerating voltage of STEM is 10 kV or more and 30 kV or less, and the magnification of STEM is 1000 times or more and 7000 times or less.

-component-
It is preferable that the anti-glare layer mainly contains a resin component. Furthermore, the anti-glare layer may contain particles such as organic particles and inorganic particles, fine particles in nanometer units, a refractive index adjuster, an antistatic agent, a leveling agent, an ultraviolet absorber, a light stabilizer, and an antioxidant. , a viscosity modifier, a thermal polymerization initiator, and other additives are preferably included.

The anti-glare layer preferably contains a binder resin and particles.
Examples of the particles include organic particles and inorganic particles, with inorganic particles being preferred. That is, the anti-glare layer preferably contains a binder resin and inorganic particles. Moreover, it is more preferable that the anti-glare layer contains a binder resin, inorganic particles, and organic particles.

-particle-
Examples of the inorganic particles include silica, alumina, zirconia, and titania, with silica being preferred. Among the inorganic particles, amorphous inorganic particles are preferable, and amorphous silica is more preferable.
The organic particles are selected from polymethyl methacrylate, polyacrylic-styrene copolymer, melamine resin, polycarbonate, polystyrene, polyvinyl chloride, benzoguanamine-melamine-formaldehyde condensate, silicone, fluorine resin, polyester resin, etc. Examples include particles containing more than one type of resin.

The term "amorphous inorganic particles" refers to inorganic particles that do not have a specific shape and are obtained by pulverizing large-sized inorganic particles and then classifying them.

The particles preferably include inorganic particles. Moreover, it is more preferable that the particles include amorphous inorganic particles, and even more preferably, amorphous inorganic particles and organic particles are included. As the amorphous inorganic particles, amorphous silica is preferable.

Amorphous inorganic particles tend to have a larger Vvv and a smaller Sal than spherical particles. However, if the particle size distribution of the amorphous inorganic particles is too wide, Vvv tends to increase, and fingerprint wiping properties tend to deteriorate. In particular, when amorphous inorganic particles agglomerate, Vvv becomes larger, and the fingerprint wiping property is more likely to deteriorate. On the other hand, if the particle size distribution of the amorphous inorganic particles is too narrow, the coating suitability tends to decrease. For this reason, it is preferable that the volume-based cumulative distribution of the particle diameter of the amorphous inorganic particles falls within the range described below. However, inorganic particles tend to aggregate when used alone. Therefore, in order to keep Vvv within the above range and to facilitate good fingerprint wiping performance, it is preferable to keep the particle size distribution of the amorphous particles within the range described below and to use organic particles in combination.

Inorganic particles such as amorphous inorganic particles have a volume-based cumulative distribution of particle diameters d10, a volume-based cumulative distribution of particle diameters d50, and a volume-based cumulative distribution of particle diameters d90 as shown in (1) and ( It is preferable that the relationship 2) is satisfied.
1.5≦d50/d10≦4.0 (1)
1.0≦d90/d50≦3.0 (2)

When d50/d10 is 1.5 or more, it means that the particle size distribution of the inorganic particles is wide in the region where the particle size is below the average. By setting d50/d10 to 1.5 or more, fine irregularities can be easily imparted to the irregular surface, making it easier to reduce Sal. By setting d50/d10 to 4.0 or less, it is possible to suppress an increase in the amount of inorganic particles buried in the anti-glare layer and increase the addition efficiency of inorganic particles.
When d90/d50 is 1.0 or more, it means that the particle size distribution of the inorganic particles is wide in the region where the particle size is above average. By setting d90/d50 to 1.0 or more, Vvv and Sal can be easily increased. By setting d90/d50 to 3.0 or less, it is possible to easily prevent Vvv from becoming too large and Sal from becoming too large.

The lower limit of d50/d10 is more preferably 1.8 or more, more preferably 2.0 or more, and the upper limit is more preferably 3.5 or less, and even more preferably 3.0 or less. .
The lower limit of d90/d50 is more preferably 1.3 or more, more preferably 1.5 or more, and the upper limit is more preferably 2.5 or less, and even more preferably 2.0 or less. .
The d10, d50, and d90 of inorganic particles such as amorphous inorganic particles can be measured by a laser diffraction method.

The volume-based cumulative distribution d50 of particle diameters of inorganic particles such as amorphous inorganic particles is preferably 2.5 μm or more and 5.5 μm or less, more preferably 3.0 μm or more and 5.0 μm or less, More preferably, the thickness is 3.3 μm or more and 4.7 μm or less.
By setting d50 to 2.5 μm or more, it is possible to prevent the number of inorganic particles from increasing too much, and therefore it is possible to easily prevent Sal from becoming too small. By setting d50 to 5.5 μm or less, it is possible to prevent the number of inorganic particles from decreasing too much, thereby making it easier to prevent Sal from becoming too large. Moreover, by suppressing the number of inorganic particles from decreasing too much, it is possible to easily form valleys between the particles, thereby making it easy to increase Vvv.
Regarding the thickness T of the anti-glare layer and the d50 of inorganic particles such as amorphous inorganic particles, d50/T is preferably 0.55 or more and 1.00 or less, and 0.60 or more and 0.95 or less. is more preferable, and even more preferably 0.70 or more and 0.90 or less.
By setting d50/T to 0.55 or more, Sal can be easily increased. By setting d50/T to 1.00 or less, Sal can be easily reduced.

Regarding the thickness T of the anti-glare layer and the d90 of inorganic particles such as amorphous inorganic particles, d90/T is preferably 1.00 or more and 1.50 or less, and 1.08 or more and 1.45 or less. is more preferable, and even more preferably 1.20 or more and 1.40 or less.
By setting d90/T to 1.00 or more, Vmp can be easily increased. By setting d90/T to 1.50 or less, Vmp can be easily reduced.

The content of inorganic particles such as amorphous inorganic particles is preferably 8 parts by mass or more and 40 parts by mass or less, more preferably 12 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of the binder resin. , more preferably 15 parts by mass or more and 28 parts by mass or less.
By setting the content of inorganic particles such as amorphous inorganic particles to 8 parts by mass or more, it is possible to prevent the number of inorganic particles from decreasing too much, so that the inorganic particles are densely arranged and valleys are formed between the inorganic particles. be done. Therefore, Vvv becomes a predetermined value or more, and Sal does not become too large, so that it is easy to improve the anti-glare property.
By setting the content of inorganic particles such as amorphous inorganic particles to 40 parts by mass or less, it is possible to suppress the number of inorganic particles from increasing too much, and therefore it is possible to easily suppress Sal from becoming too small.

The content of the organic particles is preferably 1 part by mass or more and 25 parts by mass or less, more preferably 3 parts by mass or more and 18 parts by mass or less, and 8 parts by mass or more and 14 parts by mass or less, based on 100 parts by mass of the binder resin. It is more preferably less than parts by mass.
By setting the content of organic particles to 1 part by mass or more, aggregation of inorganic particles can be easily suppressed. In addition, by setting the content of organic particles to 1 part by mass or more, it is possible to prevent the number of organic particles from decreasing too much, thereby making it easier to form valleys between particles. Therefore, Vvv can be easily increased. Note that as the number of particles decreases, Vmp tends to increase.
Since organic particles have a relatively uniform particle size distribution, as the content of organic particles increases, Sal tends to become smaller. Therefore, by setting the content of organic particles to 25 parts by mass or less, it is possible to prevent Sal from becoming too small and to improve the fingerprint wiping property.

The average particle diameter of the organic particles is preferably 1.0 μm or more and 5.0 μm or less, more preferably 1.2 μm or more and 3.0 μm or less, and even more preferably 1.3 μm or more and 2.5 μm or less. preferable.
By setting the average particle diameter of the organic particles to 1.0 μm or more, it is possible to prevent the number of organic particles from increasing too much, and therefore it is possible to easily prevent Sal from becoming too small. Therefore, by setting the average particle diameter of the organic particles to 1.0 μm or more, it is possible to easily improve the fingerprint wiping property. By setting the average particle diameter of the organic particles to 5.0 μm or less, it is possible to prevent the number of organic particles from decreasing too much, thereby making it easier to form valleys between the particles. Therefore, Vvv can be easily increased. Note that as the number of particles decreases, Vmp tends to increase.
In this specification, the average particle diameter of organic particles means a value determined as a volume average value d50 in a laser diffraction method.

The organic particles preferably have a narrow particle size distribution. Specifically, in the organic particles, the proportion of particles within ±0.5 μm of the average particle diameter is preferably 80% by volume or more, more preferably 85% by volume or more of the total amount of organic particles. It is preferably 90% or more, and more preferably 90% or more. By narrowing the particle size distribution of the organic particles, organic particles with uniform particle sizes are densely arranged, making it easier to prevent Vvv from becoming too large.
Examples of the shape of the organic particles include spherical, disc-shaped, rugby ball-shaped, and irregular shapes. Among these shapes, spherical organic particles are preferred because the particle size distribution can be easily controlled.

The average particle diameter of the organic particles relative to the thickness of the anti-glare layer (average particle diameter of organic particles/thickness of the anti-glare layer) is preferably 0.20 or more and 0.70 or less, and 0.23 or more and 0.50 or less. More preferably, it is 0.25 or more and 0.35 or less. By setting the average particle diameter of the organic particles/thickness of the antiglare layer within the above range, Vvv and Sal can easily be set within the above ranges.

-Inorganic fine particles-
The anti-glare layer may further contain inorganic fine particles in addition to the binder resin and particles. In this specification, inorganic fine particles and the above-mentioned particles can be distinguished by their average particle diameter.
When the anti-glare layer contains inorganic fine particles, the difference between the refractive index of the particles and the refractive index of the composition other than the particles of the anti-glare layer becomes small, and the internal haze can be easily reduced.

Examples of the inorganic fine particles include fine particles made of silica, alumina, zirconia, titania, and the like. Among these, silica is preferred because it can easily suppress the generation of internal haze.

The average particle diameter of the inorganic fine particles is preferably 1 nm or more and 200 nm or less, more preferably 2 nm or more and 100 nm or less, and even more preferably 5 nm or more and 50 nm or less.

-Binder resin-
The binder resin preferably contains a cured product of a curable resin composition, such as a cured product of a thermosetting resin composition or a cured product of an ionizing radiation-curable resin composition, in order to easily improve scratch resistance. It is more preferable to include a cured product of an ionizing radiation-curable resin composition.
The binder resin may contain a thermoplastic resin as long as the effects of the present disclosure are not impaired.

The ratio of the cured product of the curable resin composition to the total amount of the binder resin is preferably 80% by mass or more, more preferably 90% by mass or more, and 100% by mass to facilitate good scratch resistance. % is more preferable.

The thermosetting resin composition is a composition containing at least a thermosetting resin, and is a resin composition that is cured by heating.
Examples of the thermosetting resin include acrylic resin, urethane resin, phenol resin, urea melamine resin, epoxy resin, unsaturated polyester resin, and silicone resin. In the thermosetting resin composition, a curing agent is added to these curable resins as necessary.

The ionizing radiation-curable resin composition is a composition containing a compound having an ionizing radiation-curable functional group (hereinafter also referred to as "ionizing radiation-curable compound"). Examples of the ionizing radiation-curable functional group include ethylenically unsaturated bond groups such as (meth)acryloyl group, vinyl group, and allyl group, as well as epoxy group and oxetanyl group. As the ionizing radiation-curable compound, a compound having an ethylenically unsaturated bond group is preferable, a compound having two or more ethylenically unsaturated bond groups is more preferable, and among them, a compound having two or more ethylenically unsaturated bond groups, More preferred are polyfunctional (meth)acrylate compounds. As the polyfunctional (meth)acrylate compound, both monomers and oligomers can be used.
Ionizing radiation refers to electromagnetic waves or charged particle beams that have energy quanta that can polymerize or crosslink molecules, and ultraviolet (UV) or electron beam (EB) are usually used, but other types include X-rays. Electromagnetic waves such as γ rays, α rays, and charged particle beams such as ion beams can also be used.

Among polyfunctional (meth)acrylate compounds, examples of bifunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxy diacrylate, bisphenol A tetrapropoxy diacrylate, and 1,6-hexanediol. Examples include diacrylate.
Examples of trifunctional or higher-functional (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. Examples include pentaerythritol tetra(meth)acrylate, isocyanuric acid-modified tri(meth)acrylate, and the like.
The (meth)acrylate monomer may have a partially modified molecular skeleton. For example, as the above (meth)acrylate monomers, those whose molecular skeletons are partially modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol, etc. can also be used.

Examples of the polyfunctional (meth)acrylate oligomer include acrylate polymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate.
Urethane (meth)acrylates are obtained, for example, by reacting polyhydric alcohols and organic diisocyanates with hydroxy (meth)acrylates.
Preferred epoxy (meth)acrylates include (meth)acrylates obtained by reacting trifunctional or higher functional aromatic epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, etc. with (meth)acrylic acid; Aromatic epoxy resin, alicyclic epoxy resin, (meth)acrylate obtained by reacting an aliphatic epoxy resin, etc. with a polybasic acid and (meth)acrylic acid, and an aromatic epoxy resin with two or more functional groups, alicyclic It is a (meth)acrylate obtained by reacting a group epoxy resin, an aliphatic epoxy resin, etc., a phenol, and (meth)acrylic acid.

The weight average molecular weight of the polyfunctional (meth)acrylate oligomer is preferably 500 or more and 3,000 or less, more preferably 700 or more and 2,500 or less.
In this specification, the weight average molecular weight is an average molecular weight measured by GPC analysis and converted to standard polystyrene.

Further, for the purpose of adjusting the viscosity of the anti-glare layer coating liquid, a monofunctional (meth)acrylate may be used in combination as the ionizing radiation-curable compound. Monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, and cyclohexyl (meth)acrylate. , 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, and isobornyl (meth)acrylate.
The above-mentioned ionizing radiation-curable compounds can be used alone or in combination of two or more.

When the ionizing radiation curable compound is an ultraviolet curable compound, the ionizing radiation curable composition preferably contains additives such as a photopolymerization initiator and a photopolymerization accelerator.
Examples of the photopolymerization initiator include one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzyl dimethyl ketal, benzoyl benzoate, α-acyl oxime ester, thioxanthone, and the like.
The photopolymerization accelerator can reduce polymerization inhibition caused by air during curing and can speed up the curing speed. Examples of the accelerator include p-dimethylaminobenzoic acid isoamyl ester and p-dimethylaminobenzoic acid ethyl ester.

When the binder resin contains a cured product of an ionizing radiation-curable resin composition, the ionizing radiation-curable resin composition preferably contains a polyfunctional (meth)acrylate monomer and a polyfunctional (meth)acrylate oligomer.
The mass ratio of the polyfunctional (meth)acrylate monomer to the polyfunctional (meth)acrylate oligomer is preferably 5:95 to 60:40, more preferably 20:80 to 60:40, and 40: More preferably, the ratio is 60 to 60:40.
By controlling the content of the polyfunctional (meth)acrylate monomer to a predetermined ratio or more, it is possible to easily improve the scratch resistance of the anti-glare layer.
By setting the polyfunctional (meth)acrylate oligomer at a predetermined ratio or more, the viscosity of the anti-glare layer coating liquid can be increased, and it is possible to easily suppress particles from sinking below the anti-glare layer, and also to prevent convex portions based on the particles. It is possible to easily prevent the binder resin from flowing down during the process. Therefore, Vvv can be easily set to a predetermined value or more, and Sal can be easily set to a predetermined value or less. On the other hand, if the proportion of the polyfunctional (meth)acrylate oligomer becomes too large, the strength of the anti-glare layer may decrease. Furthermore, if the viscosity of the anti-glare layer coating liquid is too high, Vmp may become too large or Sal may become too small. Therefore, the ionizing radiation-curable resin composition preferably contains a predetermined amount of a polyfunctional (meth)acrylate oligomer and a predetermined amount of a polyfunctional (meth)acrylate monomer.

-Solvent, drying conditions-
The anti-glare layer coating liquid preferably contains a solvent in order to adjust the viscosity and enable each component to be dissolved or dispersed. Since the surface shape of the anti-glare layer after coating and drying differs depending on the type of solvent, it is preferable to select a solvent in consideration of the saturated vapor pressure of the solvent, the permeability of the solvent into the base material, etc.
Specifically, the solvent includes, for example, ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone (MIBK), cyclohexanone, etc.), ethers (dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic Hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated carbons (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), alcohols (isopropanol, butanol, cyclohexanol, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), glycol ethers (propylene glycol monomethyl ether acetate, etc.), cellosolve acetates, sulfoxides (dimethyl sulfoxide, etc.), amides (dimethylformamide, dimethylacetamide, etc.) etc.), and a mixture thereof may also be used.

It is preferable that the main component of the solvent in the anti-glare layer coating liquid be a solvent with a high evaporation rate. By increasing the evaporation rate of the solvent, it is possible to suppress the particles from sinking to the lower part of the anti-glare layer, and furthermore, it is possible to easily suppress the binder resin from flowing down between the convex portions based on the particles. Therefore, Vvv can be easily set to a predetermined value or more, and Sal can be easily set to a predetermined value or less.
The main component means 50% by mass or more of the total amount of the solvent, preferably 70% by mass or more, more preferably 90% by mass or more, even more preferably 97% by mass or more.
In this specification, a solvent with a high evaporation rate means a solvent with an evaporation rate of 100 or more when the evaporation rate of butyl acetate is 100. The evaporation rate of the solvent having a high evaporation rate is more preferably 120 or more and 300 or less, and even more preferably 150 or more and 220 or less.
Examples of solvents with high evaporation rates include methyl isobutyl ketone (evaporation rate 160), toluene (evaporation rate 200), and methyl ethyl ketone (evaporation rate 370).
On the other hand, examples of solvents with a slow evaporation rate of less than 100 include cyclohexanone (evaporation rate of 32) and propylene glycol monomethyl ether acetate (evaporation rate of 44).

Further, when forming an anti-glare layer from an anti-glare layer coating liquid, it is preferable to control drying conditions.
Drying conditions can be controlled by drying temperature and wind speed within the dryer. The drying temperature is preferably 30° C. or more and 120° C. or less, and the drying wind speed is preferably 0.2 m/s or more and 50 m/s or less. Further, in order to control the surface shape of the anti-glare layer by drying, it is preferable to perform irradiation with ionizing radiation after drying the coating liquid.
As for the drying conditions, it is preferable to carry out two-stage drying within the above temperature range and wind speed range. And, compared to the first stage drying, it is preferable to set the drying temperature to a higher temperature and to increase the wind speed in the second stage drying. Slow drying in the first step makes it easier to reflect the shape of the amorphous inorganic particles on the surface of the binder resin when the binder resin covers the surface of the amorphous inorganic particles. Further, by setting the drying temperature in the second stage higher than that in the first stage drying and increasing the wind speed, agglomeration of organic particles can be easily suppressed, so that it is possible to easily arrange the organic particles in a dense manner. Therefore, by carrying out two-stage drying, Vvv can be easily controlled to a predetermined value or more, and Sal can be easily controlled to be a predetermined value or less.
In the first stage drying, it is preferable that the drying temperature is 30° C. or more and less than 60° C., and the drying wind speed is 0.2 m/s or more and less than 7 m/s. In the second stage drying, it is preferable that the drying temperature is 60° C. or more and 120° C. or less, and the drying wind speed is 7 m/s or more and 50 m/s or less.

《Anti-reflection layer》
The antireflection layer is preferably located on the outermost surface on the first surface side.
Examples of the antireflection layer include a single layer structure of a low refractive index layer; a two layer structure of a high refractive index layer and a low refractive index layer; and a multilayer structure of three or more layers. The low refractive index layer and the high refractive index layer can be formed by a general-purpose wet method, dry method, or the like. In the case of a wet method, the above-mentioned single-layer structure or two-layer structure is preferable, and in the case of a dry method, the above-mentioned multi-layer structure is preferable.
Wet methods are superior to dry methods in terms of production efficiency and chemical resistance.
In the optical film of the present disclosure, the antireflection layer preferably has a single-layer structure of a low refractive index layer in order to easily maintain the uneven shape of the antiglare layer.

-In case of single layer structure or double layer structure-
A single layer structure is a single layer of a low refractive index layer, and a two layer structure is formed from a high refractive index layer and a low refractive index layer. A single-layer structure or a two-layer structure is preferably formed by a wet method.
Methods for forming an antireflection layer using a wet method include a method using a sol-gel method using a metal alkoxide, a method using a low refractive index resin such as a fluororesin, and a method using a binder resin composition. An example of this method is to apply a coating liquid containing low refractive index particles or high refractive index particles.
Among the wet methods, it is preferable to form an antireflection layer on the binder resin composition using a coating liquid of low refractive index particles or high refractive index particles for the sake of adhesion and scratch resistance. That is, the low refractive index layer preferably contains a binder resin and low refractive index particles. Moreover, it is preferable that the high refractive index layer contains a binder resin and high refractive index particles.

The lower limit of the refractive index of the low refractive index layer is preferably 1.10 or more, more preferably 1.20 or more, more preferably 1.26 or more, more preferably 1.28 or more, and more preferably 1.30 or more. The upper limit is preferably 1.48 or less, more preferably 1.45 or less, more preferably 1.40 or less, more preferably 1.38 or less, and more preferably 1.32 or less.
In this specification, the refractive index means a value at a wavelength of 550 nm.

The lower limit of the thickness of the low refractive index layer is preferably 80 nm or more, more preferably 85 nm or more, more preferably 90 nm or more, and the upper limit is preferably 150 nm or less, more preferably 110 nm or less, and more preferably 105 nm or less.

The binder resin of the low refractive index layer contains a cured product of a curable resin composition, such as a cured product of a thermosetting resin composition or a cured product of an ionizing radiation-curable resin composition, in order to improve scratch resistance. It is preferable that the composition contains a cured product of an ionizing radiation-curable resin composition.
The binder resin of the low refractive index layer may contain a thermoplastic resin as long as the effects of the present disclosure are not impaired.

Examples of the cured product of the curable resin composition for the low refractive index layer include those similar to the cured products of the curable resin composition exemplified for the anti-glare layer.
The ratio of the cured product of the curable resin composition to the total amount of the binder resin in the low refractive index layer is preferably 80% by mass or more, more preferably 90% by mass or more, and preferably 97% by mass or more. More preferred.

The binder resin of the low refractive index layer may contain a thermoplastic resin. By including a thermoplastic resin as the binder resin, the viscosity of the coating liquid for the low refractive index layer is increased, and the coating liquid for the low refractive index layer becomes difficult to flow down between the convex portions of the anti-glare layer. Therefore, by including a thermoplastic resin as the binder resin, Vvv can be easily set to a predetermined value or more, and Sal can be easily set to a predetermined value or less. Furthermore, it becomes easier to leave organic Si and fluorine near the surface of the first surface, making it easier to satisfy the element ratios of formulas 2 to 4. On the other hand, if the viscosity of the coating liquid for a low refractive index layer becomes too high, defects may occur on the surface of the anti-glare layer during application of the coating liquid for an antireflection layer.
The content of the thermoplastic resin is preferably 0.1% by mass or more and 3.0% by mass or less, more preferably 0.2% by mass or more based on the total amount of the binder resin, for the above-mentioned effects and coating strength. It is 1.5% by mass or less, more preferably 0.3% by mass or more and 0.7% by mass or less.

Thermoplastic resins include polystyrene resins, polyolefin resins, ABS resins (including heat-resistant ABS resins), AS resins, AN resins, polyphenylene oxide resins, polycarbonate resins, polyacetal resins, acrylic resins, and polyethylene terephthalate resins. Examples include resins, polybutylene tephthalate resins, polysulfone resins, and polyphenylene sulfide resins, with acrylic resins being preferred from the viewpoint of transparency.
The weight average molecular weight of the thermoplastic resin is preferably 20,000 or more and 200,000 or less, more preferably 30,000 or more and 150,000 or less, and even more preferably 50,000 or more and 100,000 or less.

Examples of low refractive index particles include hollow particles and solid particles. Although the low refractive index particles may include only either hollow particles or solid particles, it is preferable to include hollow particles in order to lower the refractive index. In order to suppress a decrease in coating film strength of the low refractive index layer, solid particles may be further included in addition to hollow particles. Note that by including only hollow particles without including solid particles, the effects of the present disclosure can be easily exhibited.
The material of the hollow particles and the solid particles may be any of inorganic compounds such as silica and magnesium fluoride, and organic compounds, but silica is preferable for low refractive index and strength. That is, the low refractive index layer preferably contains hollow silica particles. Moreover, it is also preferable that the low refractive index layer further contains solid silica particles in addition to the hollow silica particles.

The average primary particle diameter of the hollow particles is preferably smaller than the thickness of the low refractive index layer, for example, from 1 nm to 150 nm. The average primary particle diameter of the hollow particles is preferably 35 nm or more and 100 nm or less, more preferably 50 nm or more and 100 nm or less, and even more preferably 60 nm or more and 80 nm or less.
The average primary particle diameter of the solid particles is preferably smaller than the thickness of the low refractive index layer, for example, from 0.5 nm to 100 nm. The average primary particle diameter of the solid particles is preferably 1 nm or more and 30 nm or less, more preferably 5 nm or more and 20 nm or less, and even more preferably 10 nm or more and 15 nm or less.

The average primary particle diameter of hollow particles, solid particles described below, and high refractive particles described below can be calculated by the following operations (A1) to (A3).
(A1) A cross section of the antireflection member is imaged using TEM or STEM. It is preferable that the accelerating voltage of TEM or STEM is 10 kV to 30 kV, and the magnification is 50,000 to 300,000 times.
(A2) Extract ten arbitrary particles from the observed image and calculate the particle diameter of each particle. The particle diameter is measured as the distance between two parallel straight lines in a combination such that when the cross section of the particle is sandwiched between two arbitrary parallel straight lines, the distance between the two straight lines becomes the maximum.
(A3) Perform the same operation five times on the observation image of the same sample on another screen, and use the value obtained from the number average of the particle diameters of a total of 50 particles as the average primary particle diameter of the particles.

As the content of hollow particles increases, the filling rate of hollow particles in the binder resin increases, and the refractive index of the low refractive index layer decreases. Therefore, the content of the hollow particles is preferably 100 parts by mass or more, more preferably 150 parts by mass or more, based on 100 parts by mass of the binder resin.
On the other hand, if the content of hollow particles is too large, the hollow particles are likely to be damaged or fall off, and the mechanical strength such as scratch resistance of the low refractive index layer tends to decrease. Moreover, if the content of hollow particles is too large, it may become difficult to satisfy the above formulas 2 and 3. Therefore, the content of the hollow particles is preferably 300 parts by mass or less, more preferably 250 parts by mass or less, based on 100 parts by mass of the binder resin.

In order to improve the scratch resistance of the low refractive index layer, the content of the solid particles is preferably 20 parts by mass or more, more preferably 40 parts by mass or more, based on 100 parts by mass of the binder resin. preferable.
On the other hand, if the content of solid particles is too large, the solid particles tend to aggregate. Moreover, if the content of solid particles is too large, it may become difficult to satisfy the above formulas 2 and 3. Therefore, the content of the solid particles is preferably 100 parts by mass or less, more preferably 60 parts by mass or less, based on 100 parts by mass of the binder resin.

The low refractive index layer preferably contains a leveling agent containing organic Si and fluorine so that the first surface easily satisfies the element ratios of formulas 2 to 4 above. The leveling agent containing organic Si and fluorine may be a compound containing organic Si and fluorine in the molecule. Further, as the leveling agent containing organic Si and fluorine, a compound containing organic Si in the molecule and a compound containing fluorine in the molecule may be used in combination. In order to easily improve compatibility with the binder resin, the low refractive index layer preferably contains a compound containing organic Si and fluorine in one molecule as a leveling agent. The leveling agent preferably has a functional group reactive with the binder resin in its molecule.
The element ratios in formulas 2 to 4 above can be adjusted mainly by the content of the leveling agent and the proportions of organic Si and fluorine in the leveling agent. However, it is difficult to control the amount of the low refractive index layer coating liquid that flows between the convex portions of the anti-glare layer only by the content of the leveling agent and the proportions of organic Si and fluorine in the leveling agent. In order to easily satisfy the element ratios of formulas 2 to 4 above, the viscosity of the coating liquid for the low refractive index layer is increased or the drying conditions of the coating liquid for the low refractive index layer are controlled. It is preferable to reduce the amount of the coating liquid for a low refractive index layer that flows down between the convex portions.

The preferred content of the leveling agent is preferably adjusted to satisfy the element ratios of formulas 2 to 4 above, depending on the proportions of organic Si and fluorine in the leveling agent.
In one embodiment of the present disclosure, the content of the leveling agent based on the total solid content of the low refractive index layer is preferably 10% by mass or more and 40% by mass or less, and preferably 15% by mass or more and 40% by mass or less. More preferably, it is 20% by mass or more and 40% by mass or less.

The high refractive index layer is preferably arranged closer to the anti-glare layer than the low refractive index layer.
The lower limit of the refractive index of the high refractive index layer is preferably 1.53 or more, more preferably 1.54 or more, more preferably 1.55 or more, more preferably 1.56 or more, and the upper limit is 1.85 or less. is preferable, 1.80 or less is more preferable, 1.75 or less is more preferable, and 1.70 or less is more preferable.

The upper limit of the thickness of the high refractive index layer is preferably 200 nm or less, more preferably 180 nm or less, even more preferably 150 nm or less, and the lower limit is preferably 50 nm or more, more preferably 70 nm or more.

Examples of the binder resin for the high refractive index layer include those similar to those for the low refractive index layer.

Examples of high refractive index particles include antimony pentoxide, zinc oxide, titanium oxide, cerium oxide, tin-doped indium oxide, antimony-doped tin oxide, yttrium oxide, and zirconium oxide.
The average primary particle diameter of the high refractive index particles is preferably 2 nm or more, more preferably 5 nm or more, and even more preferably 10 nm or more. In addition, from the viewpoint of suppressing whitening and transparency, the average primary particle diameter of the high refractive index particles is preferably 200 nm or less, more preferably 100 nm or less, more preferably 80 nm or less, more preferably 60 nm or less, and more preferably 30 nm or less. .
The content of the high refractive index particles may be such that the refractive index of the high refractive index layer falls within the range described above.

When forming antireflection layers such as a low refractive index layer and a high refractive index layer by a wet method, it is preferable to increase the viscosity of the antireflection layer coating liquid. By increasing the viscosity of the coating solution for the anti-reflection layer, the coating solution for the anti-reflection layer becomes difficult to flow down between the convex parts of the anti-glare layer, so even if the anti-reflection layer is formed on the anti-glare layer, the The surface shape of the glare layer can be easily maintained. Therefore, by appropriately increasing the viscosity of the antireflection layer coating liquid, Vvv can be easily controlled to a predetermined value or more, and Sal can be easily controlled to be a predetermined value or less. Furthermore, it becomes easier to leave organic Si and fluorine near the surface of the first surface, making it easier to satisfy the element ratios of formulas 2 to 4. For example, by adding a thermoplastic resin as a binder resin, increasing the proportion of oligomer in an ionizing radiation-curable resin composition, or selecting a highly viscous solvent as a solvent, the coating solution for an antireflection layer can be improved. Viscosity can be increased.
On the other hand, if the viscosity of the antireflection layer coating liquid is made too high, defects may occur on the surface of the antiglare layer during coating of the antireflection layer coating liquid.
Therefore, the viscosity of the antireflection layer coating liquid at 23° C. is preferably 0.1 mPa·s or more and 5.0 mPa·s or less.

Examples of the solvent for the antireflection layer coating solution include the same solvents as those exemplified as the solvent for the antiglare layer coating solution.

When forming an anti-glare layer from an anti-reflection layer coating liquid, it is preferable to control drying conditions.
Drying conditions can be controlled by drying temperature and wind speed within the dryer. The drying temperature is preferably 30° C. or more and 70° C. or less, and the drying wind speed is preferably 10 m/s or more and 30 m/s or less. By setting the drying temperature to a low temperature, it is possible to easily increase the viscosity of the coating liquid for an antireflection layer. Furthermore, by increasing the wind speed, the viscosity of the antireflection layer coating liquid can be quickly increased. Therefore, by drying the antireflection layer coating liquid at a relatively low temperature and at a strong wind speed, the antireflection layer coating liquid can be prevented from flowing down between the convex portions of the antiglare layer. That is, by drying the coating solution for the antireflection layer at a relatively low temperature and at a strong wind speed, the surface shape of the first surface, such as Vvv, can be easily brought into the above-mentioned range, and Equations 1 to 4 can be easily satisfied. .
Irradiation with ionizing radiation is preferably performed after drying the antireflection layer coating solution.

-In the case of a multilayer structure with three or more layers-
A multilayer structure preferably formed by a dry method has a structure in which a total of three or more layers of high refractive index layers and low refractive index layers are alternately laminated. Even in a multilayer structure, the low refractive index layer is preferably placed on the outermost surface of the optical film.

The high refractive index layer preferably has a thickness of 10 nm or more and 200 nm or less, and preferably has a refractive index of 2.10 or more and 2.40 or less. The thickness of the high refractive index layer is more preferably 20 nm or more and 70 nm or less.
The low refractive index layer preferably has a thickness of 5 nm or more and 200 nm or less, and a refractive index of 1.33 or more and 1.53 or less. The thickness of the low refractive index layer is more preferably 20 nm or more and 120 nm or less.

<Optical properties>
It is preferable that the optical film has an _RSCI , which is a total light reflectance measured by the method described below, of 3.0% or less.
[Measurement of total light reflectance ( _RSCI )]
A sample is prepared by bonding a black plate to the second surface of the optical film via a transparent adhesive. The total light reflectance ( _RSCI ) is measured using the optical film side of the sample as the light incident surface.

By setting the R _SCI to 3.0% or less, it is possible to easily increase the blackness of the black display area in an environment in which high-intensity light is not incident on the first surface, thereby making it easy to improve the contrast. The _RSCI of the optical film is more preferably 2.5% or less, and even more preferably 2.0% or less. The lower limit of the _RSCI of the optical film is not particularly limited, but is usually 0.1% or more.

Generally, when the _RSCI is set to 3.0% or less, the contrast in reflectance between a portion having a fingerprint component and a portion not having a fingerprint component increases, and the appearance of the optical film tends to deteriorate significantly. However, since the optical film of the present disclosure has good fingerprint wiping properties by increasing the falling contact angle, it is easy to suppress deterioration in the appearance of the optical film even if the _RSCI is 3.0% or less. can.

_RSCI is reflected light measured by applying light to the sample surface from all directions using an integrating sphere and closing a light trap corresponding to the direction of specular reflection.
A typical _RSCI measuring device has a configuration conforming to geometric condition c of JIS Z8722:2009. More specifically, a typical _RSCI measurement device uses a D65 as the light source of an integrating sphere spectrophotometer, the position of the receiver is +8 degrees with respect to the normal to the sample, and the aperture angle of the receiver is is 10 degrees, the light trap position is −8 degrees with respect to the sample normal, and the viewing angle is 2 degrees or 10 degrees. In this specification, the viewing angle is set to 2 degrees.
An example of a measuring device that satisfies the above conditions is an integrating sphere spectrophotometer (trade name: CM-2002) manufactured by Konica Minolta.

The difference between the refractive index of the transparent adhesive of the sample and the refractive index of the layer on the second surface side of the optical film is preferably within 0.05, more preferably within 0.03, and more preferably within 0.03. More preferably, it is within 0.01. The difference between the refractive index of the transparent adhesive of the sample and the refractive index of the binder resin of the black plate is preferably within 0.05, more preferably within 0.03, and more preferably within 0.01. It is even more preferable.

The optical film preferably has a total light transmittance of 80% or more according to JIS K7361-1:1997, more preferably 85% or more, and even more preferably 90% or more.
The light incident surface when measuring the total light transmittance and haze is the second surface side of the optical film.

The optical film preferably has a haze of 20% or more and 75% or less according to JIS K7136:2000. The lower limit of haze is more preferably 30% or more, further preferably 40% or more, even more preferably 50% or more, and the upper limit is more preferably 70% or less, 65%. It is more preferable that it is the following.
By setting the haze to 20% or more, anti-glare properties can be easily improved. Further, by setting the haze to 75% or less, it is possible to easily suppress a decrease in image resolution.
Embodiments of the haze of the optical film include 20% or more and 75% or less, 20% or more and 70% or less, 20% or more and 65% or less, 30% or more and 75% or less, 30% or more and 70% or less, and 30% or more and 65% or less. , 40% or more and 75% or less, 40% or more and 70% or less, 40% or more and 65% or less, 50% or more and 75% or less, 50% or more and 70% or less, and 50% or more and 65% or less.

In order to easily improve the resolution and contrast of images, the optical film preferably has an internal haze of 20% or less, more preferably 15% or less, and even more preferably 10% or less.
Internal haze can be measured by a general-purpose method, for example, by bonding a transparent sheet on the first surface of an optical film via a transparent adhesive layer and flattening the irregularities on the first surface. be able to.

Regarding the transmitted image clarity measured in accordance with JIS K7374:2007, the optical film has a transmitted image clarity of C _0.125 when the width of the optical comb is 0.125 mm, and a transmitted image clarity when the width of the optical comb is 0.25 mm. C _0.25 is the clarity of the transmitted image when the width of the optical comb is 0.5 mm, C _0.5 is the clarity of the transmitted image when the width of the optical comb is 1.0 mm, and C _1.0 is the clarity of the transmitted image when the width of the optical comb is 2.0 mm. When the degree is defined as C _2.0 , the values of C _0.125 , C _0.25 , C _0.5 , C _1.0 and C _2.0 are preferably in the following ranges.
In order to improve anti-glare properties, C _0.125 is preferably 50% or less, more preferably 40% or less, more preferably 30% or less, and even more preferably 20% or less. C _0.125 is preferably 1.0% or more in order to improve resolution. The range of C _0.125 includes 1.0% to 50%, 1.0% to 40%, 1.0% to 30%, and 1.0% to 20%.
In order to improve anti-glare properties, C _0.25 is preferably 50% or less, more preferably 40% or less, more preferably 30% or less, and even more preferably 20% or less. C _0.25 is preferably 1.0% or more in order to improve resolution. Examples of the range of C _0.25 include 1.0% to 50%, 1.0% to 40%, 1.0% to 30%, and 1.0% to 20%.
In order to improve anti-glare properties, C _0.5 is preferably 50% or less, more preferably 40% or less, more preferably 30% or less, and even more preferably 20% or less. C _0.5 is preferably 1.0% or more in order to improve resolution. Examples of the range of C _0.5 include 1.0% to 50%, 1.0% to 40%, 1.0% to 30%, and 1.0% to 20%.
In order to improve anti-glare properties, C _1.0 is preferably 50% or less, more preferably 40% or less, more preferably 30% or less, and even more preferably 20% or less. C _1.0 is preferably 1.0% or more in order to improve resolution. Examples of the range of C _1.0 include 1.0% to 50%, 1.0% to 40%, 1.0% to 30%, and 1.0% to 20%.
In order to improve anti-glare properties, C _2.0 is preferably 50% or less, more preferably 40% or less, more preferably 30% or less, and even more preferably 20% or less. C _2.0 is preferably 5.0% or more in order to improve resolution. Examples of the range of C _2.0 include 5.0% to 50%, 5.0% to 40%, 5.0% to 30%, and 5.0% to 20%.

In order to improve the anti-glare properties of the optical film, the total of C _0.125 , C _0.5 , C _1.0 and C _2.0 is preferably 200% or less, more preferably 150% or less, more preferably 100% or less, and 80%. The following are more preferred. The total is preferably 10.0% or more in order to improve resolution. Examples of the range of the total include 10.0% to 200%, 10.0% to 150%, 10.0% to 100%, and 10.0% to 80%.

<Size, shape, etc.>
The optical film may be in the form of a sheet cut into a predetermined size, or may be in the form of a roll formed by winding a long sheet into a roll. The size of the leaves is not particularly limited, but the maximum diameter is about 2 inches or more and 500 inches or less. The term "maximum diameter" refers to the maximum length when any two points on the optical film are connected. For example, if the optical film is rectangular, the diagonal line of the area has the maximum diameter. When the optical film is circular, the diameter of the circle is the maximum diameter.
The width and length of the roll are not particularly limited, but generally the width is about 500 mm or more and 3000 mm or less, and the length is about 500 m or more and 5000 m or less. The optical film in the form of a roll can be used by cutting it into sheets according to the size of the image display device or the like. When cutting, it is preferable to exclude the ends of the roll whose physical properties are unstable.
The shape of the sheet is not particularly limited, and examples thereof include polygons such as triangles, quadrangles, and pentagons, circles, and random irregular shapes. More specifically, when the optical film has a rectangular shape, the aspect ratio is not particularly limited as long as it poses no problem as a display screen. For example, width:height = 1:1, 4:3, 16:10, 16:9, 2:1, etc. However, in automotive applications and digital signage with rich design, it is limited to these aspect ratios. Not done.

Although the surface shape of the second surface of the optical film is not particularly limited, it is preferably substantially smooth. Substantially smooth means that the arithmetic mean roughness Ra according to JIS B0601:1994 at a cutoff value of 0.8 mm is less than 0.03 μm, preferably 0.02 μm or less.

[Optical film manufacturing method]
The method for manufacturing an optical film of the present disclosure is the method for manufacturing an optical film of the present disclosure described above, which includes a first step of forming an anti-glare layer on a base material, and forming an anti-reflection layer on the anti-glare layer. and a second step of forming.

Means for forming the anti-glare layer on the substrate include the above-mentioned (A) method using an embossing roll, (B) etching treatment, (C) molding with a mold, (D) formation of a coating film by coating, can be mentioned.
In the case of method (A), for example, an anti-glare layer can be formed on the base material by forming a resin layer on the base material and shaping it from the resin layer side using an embossing roll.
In the case of method (B), for example, an anti-glare layer can be formed on the substrate by forming a layer of photocurable resin on the substrate and photo-etching it.
In the case of method (C), for example, an anti-glare layer can be formed on a base material by pouring a resin into a mold, taking out the molded resin from the mold, and placing it on the base material.
In the case of method (D), for example, an anti-glare layer can be formed on the substrate by forming a coating film on the substrate by the method (d1) or (d2) described above.

Examples of means for forming the antireflection layer on the antiglare layer include the above-mentioned wet method or dry method.

[Polarizer]
The polarizing plate of the present disclosure includes a polarizer, a first transparent protective plate placed on one side of the polarizer, and a second transparent protective plate placed on the other side of the polarizer. A polarizing plate,
At least one of the first transparent protective plate and the second transparent protective plate is the optical film of the present disclosure described above, and the second surface of the optical film and the polarizer are disposed to face each other. It is something.

<Polarizer>
Examples of polarizers include sheet-type polarizers such as polyvinyl alcohol films dyed with iodine and stretched, polyvinyl formal films, polyvinyl acetal films, saponified ethylene-vinyl acetate copolymer films, etc., and many sheets arranged in parallel. Examples include wire grid type polarizers made of metal wires, coated type polarizers coated with lyotropic liquid crystal or dichroic guest-host materials, and multilayer thin film type polarizers. These polarizers may be reflective polarizers having a function of reflecting polarized light components that are not transmitted.

<Transparent protection plate>
A first transparent protection plate is arranged on one side of the polarizer, and a second transparent protection plate is arranged on the other side. At least one of the first transparent protection plate and the second transparent protection plate is the optical film of the present disclosure described above.
In the polarizing plate of the present disclosure, one of the first transparent protective plate and the second transparent protective plate may be the optical film of the present disclosure described above, or the first transparent protective plate and the second transparent protective plate may be the optical film of the present disclosure. Both may be the optical film of the present disclosure described above.

Among the first transparent protection plate and the second transparent protection plate, a general-purpose plastic film, glass, or the like can be used as the transparent protection plate that is not the optical film of the present disclosure.

It is preferable that the polarizer and the transparent protective plate are bonded together via an adhesive. A general-purpose adhesive can be used as the adhesive, and a PVA-based adhesive is preferable.

[Surface plate for image display device]
The surface plate for an image display device of the present disclosure is a surface plate for an image display device in which a protective film is laminated onto a resin plate or a glass plate, and the protective film is the optical film of the present disclosure described above, The second surface of the optical film and the resin plate or the glass plate are arranged to face each other.

As the resin plate or glass plate, a resin plate or a glass plate that is commonly used as a surface plate of an image display device can be used.

The thickness of the resin plate or glass plate is preferably 10 μm or more in order to improve the strength. The upper limit of the thickness of the resin plate or glass plate is usually 5000 μm or less. In order to reduce the thickness, the upper limit of the thickness of the resin plate or glass plate is preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably 100 μm or less.
Examples of the thickness range of the resin plate or glass plate include 10 μm or more and 5000 μm or less, 10 μm or more and 1000 μm or less, 10 μm or more and 500 μm or less, and 10 μm or more and 100 μm or less.

[Image display panel]
The image display panel of the present disclosure is an image display panel having a display element and an optical film disposed on the light exit surface side of the display element, and includes the optical film of the present disclosure described above as the optical film ( (see Figure 2).

In the image display panel, the optical film of the present disclosure is preferably arranged such that the second surface side faces the display element side.
In the image display panel, the optical film of the present disclosure is preferably disposed on the outermost surface on the light exit surface side of the display element.

Examples of display elements include liquid crystal display elements, EL display elements (organic EL display elements, inorganic EL display elements), plasma display elements, and further, LED display elements such as micro LED display elements. These display elements may have a touch panel function inside the display element.
Examples of the liquid crystal display method of the liquid crystal display element include an IPS method, a VA method, a multi-domain method, an OCB method, an STN method, and a TSTN method.

Further, the image display panel of the present disclosure may be an image display panel with a touch panel that has a touch panel between a display element and an optical film.

The size of the image display panel is not particularly limited, but the maximum diameter is about 2 inches or more and 500 inches or less. The maximum diameter means the maximum length when connecting any two points within the plane of the image display panel.

[Image display device]
The image display device of the present disclosure includes the image display panel of the present disclosure.

The image display device of the present disclosure is not particularly limited as long as it includes the image display panel of the present disclosure. It is preferable that the image display device of the present disclosure includes the image display panel of the present disclosure, a drive control section electrically connected to the image display panel, and a housing that accommodates these.
When the display element is a liquid crystal display element, the image display device of the present disclosure requires a backlight. The backlight is arranged on the side opposite to the light exit surface of the liquid crystal display element.

The size of the image display device is not particularly limited, but the maximum diameter of the effective display area is about 2 inches or more and 500 inches or less.
The effective display area of an image display device is an area where an image can be displayed. For example, when an image display device has a casing that surrounds a display element, the area inside the casing becomes the effective image area.
Note that the maximum diameter of the effective image area refers to the maximum length when any two points within the effective image area are connected. For example, if the effective image area is rectangular, the diagonal line of the area has the maximum diameter. Furthermore, when the effective image area is circular, the diameter of the area is the maximum diameter.

[How to select optical film]
The optical film selection method of the present disclosure selects an optical film that satisfies the following selection conditions.
(Selection conditions for optical film)
An optical film having a first surface and a second surface opposite to the first surface,
The optical film has an antireflection layer and an antiglare layer in this order from the first surface to the second surface,
the first surface has an uneven shape;
The first surface has a protruding valley space volume Vvv defined in ISO 25178-2:2012 of 0.005 ml/m ² or more,
The falling contact angle measured by the method below is 30.0 degrees or more.
<Measurement of falling contact angle>
A droplet having a surface tension of 30 mN/m is dropped from a height of 45 mm onto the first surface of the optical film. The droplet is caused to fall from a direction perpendicular to the first surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method.
It includes the image display panel of the present disclosure.

The optical film selection method of the present disclosure may include additional selection conditions. Additional selection criteria include preferred embodiments of the optical film. Additional selection conditions include, for example, the following A to D.
A: Vvv/Vvc is 0.10 or less.
B: The optical film has the antireflection layer, the antiglare layer, and the base material in this order from the first surface to the second surface.
C: The element ratio satisfies the following formulas 2 to 4.
3.5≦F/Inorganic Si≦10.0 (Formula 2)
0.08≦Organic Si/Inorganic Si≦1.00 (Formula 3)
5.0≦F/Organic Si≦50.0 (Formula 4)
D: _RSCI , which is the total light reflectance measured by the method below, is 3.0% or less.
[Measurement of total light reflectance ( _RSCI )]
A sample is prepared by bonding a black plate to the second surface of the optical film via a transparent adhesive. The total light reflectance ( _RSCI ) is measured using the optical film side of the sample as the light incident surface.

According to the optical film selection method of the present disclosure, it is possible to efficiently select an optical film that has excellent anti-glare properties and good fingerprint wiping properties.

[Evaluation method of fingerprint wiping performance]
The fingerprint wiping property evaluation method of the present disclosure uses the value of the falling contact angle measured by the following measurement as an evaluation index.
<Measurement of falling contact angle>
A droplet with a surface tension of 30 mN/m is dropped from a height of 45 mm onto the surface of the object to be measured. The droplet is caused to fall from a direction perpendicular to the surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method.

According to the fingerprint wiping property evaluation method of the present disclosure, it is possible to easily evaluate the fingerprint wiping property of a measurement target. Specifically, it can be evaluated that the smaller the value of the falling contact angle is, the better the fingerprint wiping property is.

The present disclosure includes the following [1] to [17].
[1] An optical film having a first surface and a second surface opposite to the first surface,
The optical film has an antireflection layer and an antiglare layer in this order from the first surface to the second surface,
the first surface has an uneven shape;
The first surface has a protruding valley space volume Vvv defined in ISO 25178-2:2012 of 0.005 ml/m ² or more,
An optical film having a falling contact angle of 30.0 degrees or more as measured by the method below.
<Measurement of falling contact angle>
A droplet having a surface tension of 30 mN/m is dropped from a height of 45 mm onto the first surface of the optical film. The droplet is caused to fall from a direction perpendicular to the first surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method.
[2] In [1], the first surface has a ratio of Vvv to Vvc, which is the core space volume defined in ISO 25178-2:2012, (Vvv/Vvc) is 0.10 or less. The optical film described.
[3] The optical device according to [1] or [2], wherein the first surface has a minimum autocorrelation length Sal of 4.0 μm or more and 12.0 μm or less as defined in ISO 25178-2:2012. film.
[4] The first surface has a pole height Sxp defined in ISO 25178-2:2012 of 0.15 μm or more and 2.00 μm or less, according to any one of [1] to [3]. optical film.
[5] The optical film according to any one of [1] to [4], wherein the optical film has the antireflection layer, the antiglare layer, and the base material in this order from the first surface to the second surface. optical film.
[6] The optical film according to any one of [1] to [5], wherein the anti-glare layer contains a binder resin and particles.
[7] The optical film is any one of [1] to [6], wherein the element ratio obtained by analyzing the surface area on the first surface side by X-ray photoelectron spectroscopy satisfies the following formulas 2 to 4. An optical film described in Crab.
3.5≦F/Inorganic Si≦10.0 (Formula 2)
0.08≦Organic Si/Inorganic Si≦1.00 (Formula 3)
5.0≦F/Organic Si≦50.0 (Formula 4)
[In formulas 2 to 4, "F" is the ratio of fluorine element, "inorganic Si" is the ratio of silicon element belonging to inorganic silicon compounds, and "organic Si" is the ratio of silicon element belonging to organosilicon compounds. It is a ratio. ]
[8] The optical film according to [7], wherein the ratio of inorganic Si to all elements is 2 at % or more and 20 at % or less with respect to the element ratio obtained by analysis by the X-ray photoelectron spectroscopy.
[9] The optical film according to any one of [1] to [8], wherein the optical film has a total light reflectance, _RSCI , of 3.0% or less as measured by the method described below.
[Measurement of total light reflectance ( _RSCI )]
A sample is prepared by bonding a black plate to the second surface of the optical film via a transparent adhesive. The total light reflectance ( _RSCI ) is measured using the optical film side of the sample as the light incident surface.
[10] The optical film according to any one of [1] to [9], which has a haze of 20% or more and 75% or less according to JIS K7136:2000.
[11] A polarizing plate comprising a polarizer, a first transparent protective plate disposed on one side of the polarizer, and a second transparent protective plate disposed on the other side of the polarizer. hand,
At least one of the first transparent protective plate and the second transparent protective plate is the optical film according to any one of [1] to [10], and the second surface of the optical film and the polarizer Polarizing plate placed facing each other.
[12] A surface plate for an image display device in which a protective film is laminated on a resin plate or a glass plate, wherein the protective film is the optical film according to any one of [1] to [10], and the A surface plate for an image display device, in which the second surface of an optical film and the resin plate or the glass plate are arranged to face each other.
[13] An image display panel comprising a display element and an optical film disposed on the light exit surface side of the display element, wherein the optical film is the optical film according to any one of [1] to [10]. Including, image display panel.
[14] An image display device including the image display panel according to [13].
[15] A method for producing an optical film according to any one of [1] to [10], comprising:
An optical film manufacturing method comprising a first step of forming an anti-glare layer on a base material and a second step of forming an anti-reflection layer on the anti-glare layer.
[16] An optical film selection method that selects an optical film that satisfies the following selection conditions.
(Selection conditions for optical film)
An optical film having a first surface and a second surface opposite to the first surface,
The optical film has an antireflection layer and an antiglare layer in this order from the first surface to the second surface,
the first surface has an uneven shape;
The first surface has a protruding valley space volume Vvv defined in ISO 25178-2:2012 of 0.005 ml/m ² or more,
The falling contact angle measured by the method below is 30.0 degrees or more.
<Measurement of falling contact angle>
A droplet having a surface tension of 30 mN/m is dropped from a height of 45 mm onto the first surface of the optical film. The droplet is caused to fall from a direction perpendicular to the first surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method.
[17] A method for evaluating fingerprint wiping performance, using the value of the falling contact angle measured by the following measurement as an evaluation index.
<Measurement of falling contact angle>
A droplet with a surface tension of 30 mN/m is dropped from a height of 45 mm onto the surface of the object to be measured. The droplet is caused to fall from a direction perpendicular to the surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method.

Next, the present disclosure will be explained in more detail with reference to examples, but the present disclosure is not limited to these examples in any way. Note that "parts" and "%" are based on mass unless otherwise specified.

1. Measurement and Evaluation The optical films of Examples and Comparative Examples were measured and evaluated as follows. The atmosphere during each measurement and evaluation was a temperature of 23±5° C. and a relative humidity of 40% to 65%. Furthermore, before starting each measurement and evaluation, the target sample was exposed to the atmosphere for 30 minutes or more and 60 minutes or less, and then the measurement and evaluation were performed. The results are shown in Table 1 or 2.

1-1. Measurement of Surface Shape The anti-glare films of Examples and Comparative Examples were cut into 10 cm x 10 cm pieces. The cutting locations were selected from random locations after visually confirming that there were no abnormalities such as dust or scratches. The substrate side of the cut anti-glare film was placed on a glass plate (2.0 mm thick) measuring 10 cm long x 10 cm wide through an optically transparent adhesive sheet made by Panac (product name: Panaclean PD-S1, thickness 25 μm). ) was prepared.
Using a confocal laser microscope (VK-X250 (control unit), VK-X260 (measurement unit)), set the sample 1 so that it is fixed and in close contact with the measurement stage, and then perform the following measurement conditions 1. The surface shape of the first surface of each sample was measured and analyzed under image processing conditions 1 and analysis conditions 1. Note that a multi-file analysis application (version 1.3.1.120) was used as the measurement and analysis software.

(Measurement conditions 1)
Laser wavelength: 408nm
Measurement optical system: Confocal optical system Objective lens: 150x Zoom: 1x Measurement area: 93.95 μm x 70.44 μm
Number of measurement points: 1024 x 768 points Measurement conditions: Transparent body surface shape/High precision/Double scan available

(Image processing condition 1)
・DCL/BCL: DCL=13000, BCL=65535, Processing method: Complement from surrounding pixels ・Height cut level: Strong (Analysis condition 1)
・Area: All areas ・Filter type: Gaussian ・S-filter: 0.25μm
・F-Operation: Plane tilt correction (area specification)
・L-filter: None ・Terminal effect correction: ON
・s when calculating Sal: s=0.20
・p, q when calculating Sxp: p=2.5%, q=50.0%

Using the analysis software, "Vvv", "Vvc", "Vmp", "Sal", and "Sxp" of each measurement area were displayed and used as measured values.

1-2. Contact angle <normal contact angle>
The optical films of Examples and Comparative Examples were cut into 10 cm square pieces. The substrate side of the cut optical film was bonded to a glass plate (10 cm long x 10 cm wide, 2.0 mm thick) via a transparent adhesive sheet to prepare a sample for measurement. The cutting location was selected from a random location on the optical film after visually confirming that there were no abnormalities such as dust or scratches. When bonding the optical film and the glass plate, care was taken not only to prevent wrinkles from forming on the optical film but also to prevent air bubbles from entering between the optical film and the glass plate.
Using a contact angle meter (DM-300, Kyowa Interface Science Co., Ltd.), drop 1.0 μL of pure water onto the first surface of each sample, and measure the static contact angle after 10 seconds of droplet deposition by θ/2. Measured according to the law. When dropping pure water, a syringe whose needle was coated with fluororesin was used.
<Falling contact angle>
A droplet with a surface tension of 30 mN/m was placed in a syringe whose needle was coated with a fluororesin. A droplet having a surface tension of 30 mN/m was allowed to fall naturally onto the first surface of each sample from a height of 45 mm. The amount of droplets that fell was 5.0 μl. The liquid used had the following composition. The droplet was dropped from a direction perpendicular to the first surface. The static contact angle 10 seconds after the droplet was deposited was measured by the θ/2 method. A contact angle meter (product number: DM-300, Kyowa Interface Science Co., Ltd.) was used as a measuring device.
<Liquid composition>
Liquid containing 100% by mass of ethylene glycol monoethyl ether (Fuji Film Wako Pure Chemical Industries, Ltd., product number: Wetting tension test mixture No. 30)

1-3. Element Ratio Measurement pieces were cut out from the optical films of Examples and Comparative Examples. Using an X-ray photoelectron spectrometer, measure the X-ray photoelectron spectra of the C1s orbit, O1s orbit, Si2p orbit, and F1s orbit of the surface area on the first surface side of each measurement piece under the conditions described below. did. Peak separation was performed for each X-ray photoelectron spectrum, and the ratios of F element, Si element, etc. were determined. Furthermore, from the X-ray photoelectron spectrum of the Si2p orbital, the proportions of Si elements belonging to inorganic silicon compounds (inorganic Si) and Si elements belonging to organosilicon compounds (organic Si) were determined.
<Measurement>
Equipment: Product name “Kratos Nova” manufactured by Shimadzu Corporation
X-ray source: AlKα
X-ray output: 150W
Emission current: 10mA
Acceleration voltage: 15kV
Measurement area: 300 x 700μm
Charge neutralization mechanism: ON
Pass energy (during narrow spectrum measurement): 40eV

1-4. Total light reflectance ( _RSCI )
The optical films of Examples and Comparative Examples were cut into 10 cm x 10 cm. The cutting locations were selected from random locations after visually confirming that there were no abnormalities such as dust or scratches. The substrate side of the cut optical film was attached to a black board (Kuraray Co., Ltd., product name: COMOGLAS DFA2CG) with a size of 10 cm long x 10 cm wide via an optical transparent adhesive sheet (product name: Panaclean PD-S1) made by Panac Co., Ltd. A sample 2 was prepared by bonding it to a 502K (black) system, 2 mm thick.
The total light reflectance (R _SCI ) was measured from the first surface side of Sample 2 using an integrating sphere spectrophotometer (manufactured by Konica Minolta, Inc., trade name: CM-2002). The light source of the integrating sphere spectrophotometer is D65, the receiver position is +8 degrees with respect to the sample normal, the receiver aperture angle is 10 degrees, and the light trap position is with respect to the sample normal. -8 degrees, and the viewing angle was 2 degrees.

1-5. Haze (Hz)
The optical films of Examples and Comparative Examples were cut into 10 cm square pieces. The cutting locations were selected from random locations after visually confirming that there were no abnormalities such as dust or scratches. The JIS K7136:2000 haze of each sample was measured using a haze meter (HM-150, manufactured by Murakami Color Research Institute).
After turning on the power switch of the device in advance to stabilize the light source, we waited for at least 15 minutes, performed calibration without setting anything in the entrance opening, and then set the measurement sample in the entrance opening and performed measurements. The light incident surface was on the base material side.
Note that the optical films of Examples and Comparative Examples both had a total light transmittance of 90% or more.

1-6. Transmitted image clarity The optical films of Examples and Comparative Examples were cut into 10 cm square pieces. The cutting locations were selected from random locations after visually confirming that there were no abnormalities such as dust or scratches. Using an image clarity measuring device manufactured by Suga Test Instruments Co., Ltd. (trade name: ICM-1T), the transmitted image clarity of the sample was measured in accordance with JIS K7374:2007. The optical comb had five widths: 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm. The light incident surface during measurement was on the base material side. Table 2 shows the values of C _0.125 , C _0.25 , C _0.5 , C _1.0 and C _2.0 and the total value of C _0.125 , C _0.5 , C _1.0 and C _2.0 .

1-7. As the dark sample, Sample 2 prepared in 1-4 was used. The sample was observed in the same manner as in 1-4 except that the observer's line of sight was changed to about 160 cm from the floor.
20 subjects evaluated based on the following evaluation points. The 20 subjects were 5 in each age group, ranging from their 20s to their 50s. The average score of the 20 evaluations was calculated and ranked based on the following criteria. It can be said that the higher the rank of the following criteria, the better the blackness of the black display area.
<Evaluation points>
(1) Items that do not feel white and are sufficiently black: 3 points (2) Items that are black but feel slightly white: 2 points (3) Items that are concerned about whiteness: 1 point <Evaluation criteria>
A: Average score is 2.5 or more B: Average score is 2.0 or more and less than 2.5 C: Average score is 1.5 or more and less than 2.0 D: Average score is less than 1.5

1-8. Anti-glare property Sample 2 prepared in 1-4 was placed on a horizontal table with a height of 70 cm in a bright room environment with the uneven surface facing upward. At that time, the sample was placed almost directly below the illumination light. The sample was observed from the front (provided that the observer did not block the illumination light), and the reflection of the illumination light on the uneven surface was evaluated using the following evaluation criteria.
For illumination, an Hf32 straight tube three-wavelength daylight white fluorescent lamp was used, and the illumination position was 2 m above the horizontal table in the vertical direction. Evaluation was made within a range in which the illuminance on the uneven surface of the sample was 500 lux or more and 1000 lux or less. The observer's line of sight was approximately 120 cm from the floor. The observer was a healthy person in his 30s with visual acuity of 0.7 or higher.
<Evaluation criteria>
A: There is no outline of the lighting, and the position cannot be determined. B: There is no outline of the lighting, but the position is vague. C: The outline and position of the lighting are vague. D: The outline of the lighting is weakly blurred, and the position is clear. I understand that

1-9. Fingerprint wiping property A cloth was soaked with 0.1 ml of the following artificial dirt. The soaking time was 10 seconds. The cloth used was "Kim Towel Wiper" manufactured by Nippon Paper Crecia Co., Ltd.
The artificial plaque soaked into the cloth was transferred onto the rubber surface under a load of 300 g/cm ² . The shape of the rubber was a cylinder with a diameter of 12 mm. The transfer time was 5 seconds. The artificial plaque transferred to the rubber surface was transferred to the first surface of Sample 2 under a load of 300 g/cm ² . The transfer time was 5 seconds. Using a spectrophotometer (manufactured by Konica Minolta, Inc., product name: CM-600d), measure the total light reflection SCI L ^* value, a ^* value, and b ^* values were measured. The obtained L ^* value, a ^* value, and b ^* value are defined as L1, a1, and b1.
Next, the black plate side of Sample 2, onto which the artificial stain had been transferred, was attached to the base of a Gakushin abrasion tester (manufactured by Tester Sangyo Co., Ltd., trade name "AB-301"). A rag was attached to the friction element of the testing machine, and the artificial dirt transferred to the first surface of Sample 2 was wiped off under the following wiping conditions. As for the cloth, the product name "ASPURE PROPREA II" manufactured by As One Company was used. Using a spectrophotometer (manufactured by Konica Minolta, Inc., product name: CM-600d), measure the total light reflection SCI L ^* value, a ^* value, and b ^* values were measured. The obtained L ^* value, a ^* value, and b ^* value are defined as L2, a2, and b2.
The color difference (ΔE) was calculated using the following formula, and the color difference values were ranked according to the following criteria. It can be said that the higher the rank of the following criteria, the better the fingerprint wiping performance.
ΔE={(L1-L2) ² + (a1-a2) ² + (b1-b2) ² } ^1/2
<Artificial plaque>
A liquid containing approximately 45% by mass of oleic acid, approximately 25% by mass of triolein, approximately 20% by mass of cholesterol oleate, approximately 4% liquid paraffin, approximately 4% squalene, and approximately 2% cholesterol (manufactured by Isekyu Co., Ltd.). Artificial grime (based on JIS C9606:2007 contaminated liquid)).
<Wiping conditions>
・Moving speed: 100mm/sec ・Load: 150g/cm ²
・Number of wiping: 1 time each way <Evaluation criteria>
A: Color difference is 2 or less B: Color difference is more than 2 and less than 4 C: Color difference is more than 4 and less than 7 D: Color difference is more than 7

1-10. Comprehensive Evaluation Based on the two evaluations of anti-glare properties and fingerprint wiping properties, a comprehensive evaluation was performed according to the following criteria.
<Evaluation criteria>
A: All two evaluations are A.
B: Of the two evaluations, one is A and one is B.
C: Out of two evaluations, both are B.
D: At least one of the two evaluations is C or D.

2. Production of optical film [Example 1]
The following anti-glare layer coating liquid 1 was applied onto a base material (80 μm thick triacetyl cellulose resin film, Fuji Film Co., Ltd.). Next, it was dried at 50° C. for 40 seconds at a wind speed of 2 m/s, and further dried at 70° C. for 45 seconds at a wind speed of 15 m/s. Next, ultraviolet rays were irradiated in a nitrogen atmosphere with an oxygen concentration of 200 ppm or less so that the cumulative amount of light was 50 mJ/cm ² to form an anti-glare layer with a thickness of 5.5 μm.
Next, the following low refractive index layer coating liquid 1 was applied onto the anti-glare layer. Next, it was dried at 40° C. for 15 seconds at a wind speed of 20 m/s, and further dried at 70° C. for 30 seconds at a wind speed of 15 m/s. Next, ultraviolet rays were irradiated in a nitrogen atmosphere with an oxygen concentration of 200 ppm or less so that the cumulative light amount was 150 mJ/cm ² to form a low refractive index layer with a thickness of 0.10 μm, and the optical film of Example 1 was obtained. Ta. The refractive index of the low refractive index layer was 1.31.

<Anti-glare layer coating liquid 1>
・Urethane acrylate A 30 parts (Mitsubishi Chemical Company, trade name: U-1700B: molecular weight 2,000, number of functional groups 10)
・Urethane acrylate B 10 parts (Shin Nakamura Chemical Industry Co., Ltd., trade name: U-15HA: molecular weight 2,300, number of functional groups 15)
・Pentaerythritol triacrylate 60 parts (Toagosei, trade name: M-305)
・23 parts of silica particles (surface treated amorphous silica, d10: 1.2 μm, d50: 3.7 μm, d90: 6.2 μm)
・8 parts of organic particles B (spherical polyacrylic-styrene copolymer, average particle diameter 1.5 μm, refractive index 1.595)
・Photopolymerization initiator 5.0 parts (IGM Resins B.V., product name: Omnirad184)
・Photopolymerization initiator 1.0 part (IGM Resins B.V., trade name: Omnirad907)
・Silicone leveling agent 0.1 part (Momentive Performance Materials, product name: TSF4460)
・Solvent (toluene) 190 parts ・Solvent (cyclohexanone) 5 parts ・Solvent (methyl isobutyl ketone) 20 parts

<Low refractive index layer coating liquid 1>
・100 parts of polyfunctional acrylate (manufactured by Toagosei Co., Ltd., trade name "Aronix M-400")
・Acrylic polymer 0.5 part (weight average molecular weight: 40,000)
・Hollow silica particles 180 parts (average primary particle diameter 75 nm, particles surface-treated with a silane coupling agent having a methacryloyl group)
・600 parts of fluorine-based silicone leveling agent having a reactive functional group (Shin-Etsu Chemical Co., Ltd., trade name "KY1203", solid content: 20%, solvent: methyl isobutyl ketone)
・Photopolymerization initiator 5.0 parts (IGM Resins, trade name "Omnirad127")
・Solvent (methyl isobutyl ketone) 11,000 parts ・Solvent (1-methoxy-2-propyl acetate) 1,300 parts

[Example 2, 3, 5, 6]
Optical films of Examples 2, 3, 5, and 6 were obtained in the same manner as in Example 1, except that anti-glare layer coating liquid 1 was changed to anti-glare layer coating liquids 2 to 5 below.

[Example 4]
The same procedure as in Example 1 was carried out, except that anti-glare layer coating liquid 1 was changed to anti-glare layer coating liquid 2 below, and low refractive index layer coating liquid 1 was changed to low refractive index layer coating liquid 2 below. An optical film of Example 4 was obtained.

[Example 7]
An optical film of Example 7 was obtained in the same manner as in Example 1, except that anti-glare layer coating liquid 1 was changed to anti-glare layer coating liquid 6 below and the thickness of the anti-glare layer was 4.8 μm. .

[Example 8]
The same procedure as in Example 1 was carried out, except that the anti-glare layer coating liquid 1 was changed to the following anti-glare layer coating liquid 2, and the low refractive index layer coating liquid 1 was changed to the following low refractive index layer coating liquid 3. An optical film of Example 8 was obtained. The refractive index of the low refractive index layer was 1.36.

[Comparative example 1]
An optical film of Comparative Example 1 was obtained in the same manner as in Example 1, except that the low refractive index layer coating liquid 1 was changed to the following low refractive index layer coating liquid 4.

[Comparative Examples 2-3]
Optical films of Comparative Examples 2 and 3 were obtained in the same manner as Comparative Example 1, except that anti-glare layer coating liquid 1 was changed to anti-glare layer coating liquids 2 and 3 below.

[Comparative example 4]
An optical film of Comparative Example 4 was obtained in the same manner as in Example 1, except that anti-glare layer coating liquid 1 was changed to anti-glare layer coating liquid 7 below and the thickness of the anti-glare layer was 5.0 μm. .

<Anti-glare layer coating liquid 2>
・Urethane acrylate A 30 parts (Mitsubishi Chemical Company, trade name: U-1700B: molecular weight 2,000, number of functional groups 10)
・Urethane acrylate B 10 parts (Shin Nakamura Chemical Industry Co., Ltd., trade name: U-15HA: molecular weight 2,300, number of functional groups 15)
・Pentaerythritol triacrylate 60 parts (Toagosei, trade name: M-305)
・21 parts of silica particles (surface-treated amorphous silica, d10: 1.2 μm, d50: 3.7 μm, d90: 6.2 μm)
- 10 parts of organic particles B (spherical polyacrylic-styrene copolymer, average particle diameter 1.5 μm, refractive index 1.595)
・Photopolymerization initiator 5.0 parts (IGM Resins B.V., product name: Omnirad184)
・Photopolymerization initiator 1.0 part (IGM Resins B.V., trade name: Omnirad907)
・Silicone leveling agent 0.1 part (Momentive Performance Materials, product name: TSF4460)
・Solvent (toluene) 180 parts ・Solvent (cyclohexanone) 15 parts ・Solvent (methyl isobutyl ketone) 20 parts

<Anti-glare layer coating liquid 3>
・Urethane acrylate A 30 parts (Mitsubishi Chemical Company, trade name: U-1700B: molecular weight 2,000, number of functional groups 10)
・Urethane acrylate B 10 parts (Shin Nakamura Chemical Industry Co., Ltd., trade name: U-15HA: molecular weight 2,300, number of functional groups 15)
・Pentaerythritol triacrylate 60 parts (Toagosei, trade name: M-305)
・Silica particles 19 parts (surface treated amorphous silica, d10: 1.2 μm, d50: 3.7 μm, d90: 6.2 μm)
・3 parts of organic particles A (spherical polyacrylic-styrene copolymer, average particle diameter 1.5 μm, refractive index 1.515)
- 5 parts of organic particles B (spherical polyacrylic-styrene copolymer, average particle diameter 1.5 μm, refractive index 1.595)
・Photopolymerization initiator 5.0 parts (IGM Resins B.V., product name: Omnirad184)
・Photopolymerization initiator 1.0 part (IGM Resins B.V., trade name: Omnirad907)
・Silicone leveling agent 0.1 part (Momentive Performance Materials, product name: TSF4460)
・Solvent (toluene) 175 parts ・Solvent (cyclohexanone) 15 parts ・Solvent (methyl isobutyl ketone) 25 parts

<Anti-glare layer coating liquid 4>
・Urethane acrylate A 30 parts (Mitsubishi Chemical Company, trade name: U-1700B: molecular weight 2,000, number of functional groups 10)
・Urethane acrylate B 10 parts (Shin Nakamura Chemical Industry Co., Ltd., trade name: U-15HA: molecular weight 2,300, number of functional groups 15)
・Pentaerythritol triacrylate 60 parts (Toagosei, trade name: M-305)
・20 parts of silica particles (surface-treated amorphous silica, d50: 3.5 μm)
・8 parts of organic particles A (spherical polyacrylic-styrene copolymer, average particle diameter 1.5 μm, refractive index 1.515)
・Organic particles B 2 parts (spherical polyacrylic-styrene copolymer, average particle diameter 1.5 μm, refractive index 1.595)
・Photopolymerization initiator 5.0 parts (IGM Resins B.V., product name: Omnirad184)
・Photopolymerization initiator 1.0 part (IGM Resins B.V., trade name: Omnirad907)
・Silicone leveling agent 0.1 part (Momentive Performance Materials, product name: TSF4460)
・Solvent (toluene) 200 parts ・Solvent (cyclohexanone) 5 parts ・Solvent (methyl isobutyl ketone) 10 parts

<Anti-glare layer coating liquid 5>
・Urethane acrylate A 30 parts (Mitsubishi Chemical Company, trade name: U-1700B: molecular weight 2,000, number of functional groups 10)
・Urethane acrylate B 10 parts (Shin Nakamura Chemical Industry Co., Ltd., trade name: U-15HA: molecular weight 2,300, number of functional groups 15)
・Pentaerythritol triacrylate 60 parts (Toagosei, trade name: M-305)
・10 parts of silica particles (surface-treated amorphous silica, d10: 0.08, d50: 2.8 μm, d90: 4.5 μm)
・5 parts of organic particles A (spherical polyacrylic-styrene copolymer, average particle diameter 1.5 μm, refractive index 1.515)
- 5 parts of organic particles B (spherical polyacrylic-styrene copolymer, average particle diameter 1.5 μm, refractive index 1.595)
・Photopolymerization initiator 5.0 parts (IGM Resins B.V., product name: Omnirad184)
・Photopolymerization initiator 1.0 part (IGM Resins B.V., trade name: Omnirad907)
・Silicone leveling agent 0.1 part (Momentive Performance Materials, product name: TSF4460)
・Solvent (toluene) 180 parts ・Solvent (cyclohexanone) 30 parts ・Solvent (methyl isobutyl ketone) 5 parts

<Anti-glare layer coating liquid 6>
・Urethane acrylate C 60 parts (Shin Nakamura Chemical Industry Co., Ltd., trade name: U-1100H: molecular weight 800, number of functional groups 6)
・Pentaerythritol triacrylate 40 parts (Toagosei, trade name: M-305)
・Organic particles C 11 parts (spherical polyacrylic-styrene copolymer, average particle diameter 3.0 μm, refractive index 1.595)
・70 parts of inorganic ultrafine particles (silica with reactive functional groups introduced onto the surface, solvent: MIBK, solid content: 30%)
(Average primary particle diameter 12 nm)
・Photopolymerization initiator 5.0 parts (IGM Resins B.V., product name: Omnirad184)
・Photopolymerization initiator 1.0 part (IGM Resins B.V., trade name: Omnirad907)
・Silicone leveling agent 0.1 part (Momentive Performance Materials, product name: TSF4460)
・Solvent (toluene) 180 parts ・Solvent (cyclohexanone) 15 parts

<Anti-glare layer coating liquid 7>
・Urethane acrylate A 30 parts (Mitsubishi Chemical Company, trade name: U-1700B: molecular weight 2,000, number of functional groups 10)
・Urethane acrylate B 10 parts (Shin Nakamura Chemical Industry Co., Ltd., trade name: U-15HA: molecular weight 2,300, number of functional groups 15)
・Pentaerythritol triacrylate 60 parts (Toagosei, trade name: M-305)
・3 parts of silica particles (surface treated amorphous silica, d10: 0.08, d50: 2.8 μm, d90: 4.5 μm)
・Organic particles B 0.5 part (spherical polyacrylic-styrene copolymer, average particle diameter 1.5 μm, refractive index 1.595)
・Photopolymerization initiator 5.0 parts (IGM Resins B.V., product name: Omnirad184)
・Photopolymerization initiator 1.0 part (IGM Resins B.V., trade name: Omnirad907)
・Silicone leveling agent 0.1 part (Momentive Performance Materials, product name: TSF4460)
・Solvent (toluene) 180 parts ・Solvent (cyclohexanone) 5 parts ・Solvent (methyl isobutyl ketone) 25 parts

<Low refractive index layer coating liquid 2>
・180 parts of polyfunctional acrylate (manufactured by Toagosei Co., Ltd., trade name "Aronix M-400")
・Hollow silica particles 100 parts (average primary particle diameter 75 nm, particles surface-treated with a silane coupling agent having a methacryloyl group)
・600 parts of fluorine-based silicone leveling agent having a reactive functional group (Shin-Etsu Chemical Co., Ltd., trade name "KY1203", solid content: 20%, solvent: methyl isobutyl ketone)
・Photopolymerization initiator 5 parts (IGM Resins, trade name "Omnirad127")
・Solvent (methyl isobutyl ketone) 11,000 parts ・Solvent (1-methoxy-2-propyl acetate) 1,300 parts

<Low refractive index layer coating liquid 3>
・100 parts of polyfunctional acrylate (manufactured by Toagosei Co., Ltd., trade name "Aronix M-400")
・Acrylic polymer 0.5 part (weight average molecular weight: 40,000)
・Hollow silica particles 100 parts (average primary particle diameter 75 nm, particles surface-treated with a silane coupling agent having a methacryloyl group)
・250 parts of fluorine-based silicone leveling agent having a reactive functional group (Shin-Etsu Chemical Co., Ltd., trade name "KY1203", solid content: 20%, solvent: methyl isobutyl ketone)
・Photopolymerization initiator 5 parts (IGM Resins, trade name "Omnirad127")
・Solvent (methyl isobutyl ketone) 11,000 parts ・Solvent (1-methoxy-2-propyl acetate) 1,300 parts

<Low refractive index layer coating liquid 4>
・100 parts of polyfunctional acrylate (manufactured by Toagosei Co., Ltd., trade name "Aronix M-400")
・Acrylic polymer 0.5 part (weight average molecular weight: 40,000)
・Hollow silica particles 180 parts (average primary particle diameter 75 nm, particles surface-treated with a silane coupling agent having a methacryloyl group)
・150 parts of fluorine-based silicone leveling agent having a reactive functional group (Shin-Etsu Chemical Co., Ltd., trade name "KY1203", solid content: 20%, solvent: methyl isobutyl ketone)
・Photopolymerization initiator 5.0 parts (IGM Resins, trade name "Omnirad127")
・Solvent (methyl isobutyl ketone) 11,000 parts ・Solvent (1-methoxy-2-propyl acetate) 1,300 parts

From the results in Table 1, it can be confirmed that the optical films of Examples can improve anti-glare properties and fingerprint wiping properties.

10: Base material 20: Anti-glare layer 30: Anti-reflection layer 100: Optical film 110: Display element 120: Image display panel

Claims (17)

An optical film having a first surface and a second surface opposite to the first surface,
The optical film has an antireflection layer and an antiglare layer in this order from the first surface to the second surface,
the first surface has an uneven shape;
The first surface has a protruding valley space volume Vvv defined in ISO 25178-2:2012 of 0.005 ml/ ^m2 or more, and a minimum autocorrelation defined in ISO 25178-2:2012. The length Sal is 4.0 μm or more and 12.0 μm or less,
An optical film having a falling contact angle of 30.0 degrees or more as measured by the method below.
<Measurement of falling contact angle>
A droplet having a surface tension of 30 mN/m is dropped from a height of 45 mm onto the first surface of the optical film. The droplet is caused to fall from a direction perpendicular to the first surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method. The optical device according to claim 1, wherein the first surface has a ratio (Vvv/Vvc) of Vvv and Vvc, which is a core space volume defined in ISO 25178-2:2012, of 0.10 or less. film. 3. The optical film according to claim 1, wherein the first surface has a minimum autocorrelation length Sal of 4.0 μm or more and 11.0 μm or less as defined in ISO 25178-2:2012. The first surface is defined by ISO 25178-2:2012, and has a pole height Sxp of 0.15 μm, which is the difference between the height at a load area ratio of 2.5% and the height at a load area ratio of 50%. The optical film according to claim 1 or 2, which has a thickness of 2.00 μm or more. The optical film according to claim 1 or 2, wherein the optical film has the antireflection layer, the antiglare layer, and a base material in this order from the first surface to the second surface. The optical film according to claim 1 or 2, wherein the anti-glare layer contains a binder resin and particles. 3. The optical film according to claim 1, wherein the element ratio obtained by analyzing the surface area on the first surface side by X-ray photoelectron spectroscopy satisfies the following formulas 2 to 4.
3.5≦F/Inorganic Si≦10.0 (Formula 2)
0.08≦Organic Si/Inorganic Si≦1.00 (Formula 3)
5.0≦F/Organic Si≦50.0 (Formula 4)
[In formulas 2 to 4, "F" is the ratio of fluorine element, "inorganic Si" is the ratio of silicon element belonging to inorganic silicon compounds, and "organic Si" is the ratio of silicon element belonging to organosilicon compounds. It is a ratio. ] 8. The optical film according to claim 7, wherein the ratio of inorganic Si to all elements is 2 atomic % or more and 20 atomic % or less with respect to the element ratio obtained by analysis by the X-ray photoelectron spectroscopy. The optical film according to claim 1 or 2, wherein the optical film has a total light reflectance, _RSCI , of 3.0% or less as measured by the following method.
[Measurement of total light reflectance ( _RSCI )]
A sample is prepared by bonding a black plate to the second surface of the optical film via a transparent adhesive. The total light reflectance ( _RSCI ) is measured using the optical film side of the sample as the light incident surface. The optical film according to claim 1 or 2, having a haze of 20% or more and 75% or less according to JIS K7136:2000. A polarizing plate comprising a polarizer, a first transparent protective plate disposed on one side of the polarizer, and a second transparent protective plate disposed on the other side of the polarizer,
At least one of the first transparent protection plate and the second transparent protection plate is the optical film according to claim 1 or 2, and the second surface of the optical film and the polarizer are opposed to each other. Polarizing plate arranged. A surface plate for an image display device in which a protective film is laminated on a resin plate or a glass plate, wherein the protective film is the optical film according to claim 1 or 2, and the second surface of the optical film and A surface plate for an image display device, wherein the resin plate or the glass plate is disposed to face each other. An image display panel comprising a display element and an optical film disposed on a light exit surface side of the display element, the image display panel comprising the optical film according to claim 1 or 2 as the optical film. An image display device comprising the image display panel according to claim 13. A method for producing an optical film according to claim 1, comprising:
An optical film manufacturing method comprising a first step of forming an anti-glare layer on a base material and a second step of forming an anti-reflection layer on the anti-glare layer. An optical film selection method that selects an optical film that satisfies the following selection conditions.
(Selection conditions for optical film)
An optical film having a first surface and a second surface opposite to the first surface,
The optical film has an antireflection layer and an antiglare layer in this order from the first surface to the second surface,
the first surface has an uneven shape;
The first surface has a protruding valley space volume Vvv defined in ISO 25178-2:2012 of 0.005 ml/ ^m2 or more, and a minimum autocorrelation defined in ISO 25178-2:2012. The length Sal is 4.0 μm or more and 12.0 μm or less,
The falling contact angle measured by the method below is 30.0 degrees or more.
<Measurement of falling contact angle>
A droplet having a surface tension of 30 mN/m is dropped from a height of 45 mm onto the first surface of the optical film. The droplet is caused to fall from a direction perpendicular to the first surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method. A method for evaluating fingerprint wiping performance using the value of the falling contact angle measured by the following method as an evaluation index.
<Measurement of falling contact angle>
A droplet with a surface tension of 30 mN/m is dropped from a height of 45 mm onto the surface of the object to be measured. The droplet is caused to fall from a direction perpendicular to the surface. The static contact angle 10 seconds after the droplet is deposited is measured by the θ/2 method.