WO2015080279A1

WO2015080279A1 - Antiglare film

Info

Publication number: WO2015080279A1
Application number: PCT/JP2014/081669
Authority: WO
Inventors: 勉古谷
Original assignee: 住友化学株式会社
Priority date: 2013-11-29
Filing date: 2014-11-25
Publication date: 2015-06-04
Also published as: KR20160091956A; CN105765417A; JP2015106038A; TW201529324A

Abstract

Provided is an antiglare film that has excellent antiglare properties at a wide observation angle even with a low haze, and that can sufficiently suppress the occurrence of white turbidity and glare when arranged on an image display device. This antiglare film comprises a transparent support body, and an antiglare layer formed thereon and having fine surface irregularities, wherein: the total haze is from 0.1% to 3% inclusive; the surface haze is from 0.1% to 2% inclusive; with respect to light that is incident at an incident angle of 30°, the ratio R(40)/R(30) between the reflectance R(30) at a reflection angle of 30° and the reflectance R(40) at a reflection angle of 40° is from 0.00001 to 0.0025 inclusive; and intensities I (0.01), I (0.02), and I (0.1) at a spatial frequency of 0.01 µm^-1, a spatial frequency of 0.02 µm^-1, and a spatial frequency of 0.1 µm^-1, respectively, in a power spectrum of the height of said surface irregularities are within respective predetermined ranges.

Description

Anti-glare film

The present invention relates to an antiglare film having excellent antiglare properties.

Image display devices such as liquid crystal display, plasma display panel, cathode ray tube (CRT) display, organic electroluminescence (EL) display, etc. An antiglare film is disposed on the display surface.
As an antiglare film, a transparent film having an uneven surface shape is mainly studied. Such an anti-glare film exhibits anti-glare properties by reducing reflection by scattering and reflecting external light (external light scattered light) due to the uneven surface shape. However, when the external light scattering light is strong, so-called “whiteness” may occur in which the entire display surface of the image display device becomes whitish or the display becomes cloudy. In addition, the pixel of the image display device and the surface unevenness of the anti-glare film interfere with each other, so that a so-called “glare” that is difficult to see due to a luminance distribution may occur. In view of the above, anti-glare films are required to sufficiently prevent the occurrence of this “whitening” and “glare” while ensuring excellent anti-glare properties.
As such an anti-glare film, for example, Patent Document 1 discloses an anti-glare film that does not generate glare even when placed in a high-definition image display device and that is sufficiently prevented from being whitish. The surface irregularity shape is fine, and the average length PSm in the arbitrary sectional curve of the surface irregularity shape is 12 μm or less, and the ratio Pa / PSm of the arithmetic average height Pa to the average length PSm in the sectional curve is An anti-glare film having a surface ratio of 0.005 or more and 0.012 or less, the surface irregularity shape having an inclination angle of 2 ° or less, and a surface ratio having an inclination angle of 6 ° or less is 90% or more. It is disclosed.
The antiglare film disclosed in Patent Document 1 has a surface irregularity shape with a period of about 50 μm that makes it easy to generate glare by making the average length PSm in an arbitrary cross-sectional curve very small, Glare can be effectively suppressed. However, when the anti-glare film disclosed in Patent Document 1 tries to make the haze smaller (to make it low haze), the anti-glare film when the display surface of the image display device on which the anti-glare film is arranged is observed obliquely. There was a case where the dazzle was reduced. Therefore, the antiglare film disclosed in Patent Document 1 has room for improvement in terms of antiglare properties at a wide observation angle.

JP 2007-188792 A

The present invention provides an anti-glare film that has excellent anti-glare properties at a wide viewing angle even at low haze, and can sufficiently suppress the occurrence of whitish and glare when placed in an image display device. The purpose is to do.

As a result of intensive studies to solve the above problems, the present inventor has completed the present invention. That is, the present invention
An anti-glare film comprising a transparent support and an anti-glare layer having fine surface irregularities formed thereon,
The total haze is 0.1% or more and 3% or less,
The surface haze is 0.1% or more and 2% or less,
For light incident at an incident angle of 30 °, the ratio R (40) / R (30) of the reflectance R (30) at a reflection angle of 30 ° and the reflectance R (40) at a reflection angle of 40 ° is 0.00001. More than 0.0025,
The surface uneven shape is an antiglare film characterized in that the power spectrum of the altitude satisfies all the following conditions (1) to (3).
(1) The intensity I (0.01) at a spatial frequency of 0.01 μm ⁻¹ is 2 μm ⁴ or more and 10 μm ⁴ or less;
(2) The intensity I (0.02) at a spatial frequency of 0.02 μm ⁻¹ is 0.1 μm ⁴ or more and 1.5 μm ⁴ or less; and (3) the intensity I at a spatial frequency of 0.1 μm ⁻¹ (0. 1) is 0.0001 μm ⁴ or more and 0.01 μm ⁴ or less.
Furthermore, in the antiglare film of the present invention,
The sum Tc of transmitted sharpness measured using five types of optical combs in which the widths of the dark part and the bright part are 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm, respectively, is 375%. That's it,
Rc of reflection sharpness Rc measured at an incident angle of 45 ° using four types of optical combs having a dark portion and a bright portion width of 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm, respectively. (45) is 180% or less,
Rc of reflection sharpness Rc measured at an incident angle of light of 60 ° using four types of optical combs in which the widths of the dark part and the bright part are 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm, respectively. (60) is preferably 240% or less.

According to the present invention, an anti-glare film having sufficient anti-glare property at a wide observation angle even with low haze and sufficiently suppressed generation of whitish and glare when placed in an image display device. Can be provided.

It is a figure for demonstrating simply the reflectance of the glare-proof film for every angle when light injects with the incident angle of 30 degrees from the glare-proof layer side. It is a figure for demonstrating simply the elevation of the surface uneven | corrugated shape of an anti-glare film. It is a figure for demonstrating simply the relationship between the altitude of the surface uneven | corrugated shape of an anti-glare film, and a coordinate (x, y). It is a schematic diagram which shows the state from which the elevation of the surface uneven | corrugated shape of an anti-glare film is obtained discretely. It is a schematic diagram which shows the state which calculates a one-dimensional power spectrum from the two-dimensional power spectrum of the elevation of the surface uneven | corrugated shape obtained as a discrete function. It is the figure which showed the one-dimensional power spectrum I (f) of the altitude of the surface uneven | corrugated shape of an anti-glare film with respect to the spatial frequency f. It is a figure which shows typically a preferable example of the manufacturing method (first half part) of a metal mold | die. It is a figure which shows typically a preferable example of the manufacturing method (second half part) of a metal mold | die. It is a figure which shows typically a preferable example of the manufacturing apparatus used for the manufacturing method of the anti-glare film of this invention. In the manufacturing method of the anti-glare film of this invention, it is a figure which shows typically a suitable precuring process. It is a figure which shows typically the unit cell for glare evaluation. It is a figure which shows a glare evaluation apparatus typically. FIG. 4 is a diagram showing a part of a pattern A used in Examples 1 to 3 and Comparative Example 1. 10 is a diagram illustrating a part of a pattern B used in Comparative Example 2. FIG.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as necessary, but the dimensions and the like shown in the drawings are arbitrary for ease of viewing.
The antiglare film of the present invention has a ratio R (40) / R of a reflectance R (30) having a reflection angle of 30 ° and a reflectance R (40) having a reflection angle of 40 ° with respect to light incident at an incident angle of 30 °. (30) is 0.00001 or more and 0.0025 or less, and the intensity at the spatial frequency of 0.01 μm ⁻¹ , 0.02 μm ⁻¹ , and 0.1 μm ⁻¹ of the power spectrum of the surface unevenness-shaped altitude is It is in the range.
First, regarding the antiglare film of the present invention, how to obtain the reflectance ratio R (40) / R (30) and the power spectrum of the elevation of the surface irregularity shape will be described.
[Reflectance ratio]
A method for obtaining the reflectance ratio R (40) / R (30) will be described.
FIG. 1 is a drawing (perspective view) for simply explaining the reflectance for each angle when light is incident at an incident angle of 30 ° from the antiglare layer side of the antiglare film of the present invention. The incident direction and the reflection direction of the light from the glare-proof layer side with respect to the film 10 are shown typically. In this figure, with respect to the incident light 11 incident at an angle of 30 ° from the normal 20 on the antiglare layer side of the antiglare film 10, the reflected light is reflected in the direction of the reflection angle of 30 °, that is, in the regular reflection direction 12. Let the rate (that is, the regular reflectance) be R (30). The reflected light at an arbitrary reflection angle θ is denoted by reference numeral 15, and the

directions

12 and 15 of the reflected light when measuring the reflectance are within the plane 30 including the direction 11 of the incident light and the normal line 20. And The reflectance in the direction with a reflection angle of 40 ° is R (40).
In measuring the reflectance of the antiglare film, it is necessary to accurately measure a reflectance of 0.001% or less. Therefore, it is effective to use a detector having a wide dynamic range, and such a commercially available optical power meter can be preferably used. An aperture is provided in front of the detector of the optical power meter, and measurement is performed using a goniophotometer in which the angle at which the antiglare film is viewed is 2 °. In this case, visible light of 380 to 780 nm can be used as incident light. As a light source for measurement, a collimated light emitted from a light source such as a halogen lamp may be used, or a monochromatic light source such as a laser having a high degree of parallelism may be used. When the reflectance is calculated for an antiglare film having a smooth and transparent back surface, reflection from the back surface of the antiglare film may affect the measurement value, and it is necessary to avoid such influence. Therefore, when measuring the reflectance, the smooth surface of the antiglare film that is the object of measurement should be adhered to the black acrylic resin plate with an adhesive or optically adhered using a liquid such as water or glycerin. Therefore, it is preferable that only the reflectance of the outermost surface of the antiglare film can be measured.
In the antiglare film of the present invention, the reflectance in the direction of the reflection angle 30 ° with respect to the incident light having the incident angle of 30 °, that is, the reflectance R (40 in the direction of the reflection angle 40 ° of the regular reflectance R (30). ) Ratio R (40) / R (30) is 0.00001 or more and 0.0025 or less. An image display device in which an antiglare film having a ratio R (40) / R (30) of less than 0.00001 has an insufficient antiglare property. On the other hand, an image display device in which an antiglare film having a ratio R (40) / R (30) exceeding 0.025 is likely to be whitish. In order to obtain an image display device having excellent antiglare properties and sufficiently prevented the occurrence of whitish, the ratio R (40) / R (30) of the antiglare film is 0.00005 or more and 0.001. The following is more preferable.
[Power spectrum of elevation of surface irregularities]
Hereinafter, the power spectrum of the elevation of the surface unevenness shape of the antiglare film will be described. FIG. 2 is a cross-sectional view schematically showing the surface of the antiglare film of the present invention. As shown in FIG. 2, the antiglare film 1 of the present invention has a transparent support 101 and an antiglare layer 102 formed thereon, and the antiglare layer 102 is opposite to the transparent support 101. Are provided with a surface uneven shape having fine unevenness 2.
Here, the “elevation of the surface uneven shape” as used in the present invention means an arbitrary point P on the surface of the film 1 and a virtual plane 103 having the height at the average height of the surface uneven shape (the altitude is used as a reference). 0 μm) means a linear distance in the main normal direction 5 (normal direction in the virtual plane 103) of the film.
Actually, as schematically shown in FIG. 3, the antiglare film has an antiglare layer having fine irregularities formed on a two-dimensional plane. Therefore, as shown in FIG. 3, the elevation of the surface irregularity shape is expressed as a two-dimensional function h (x, y) of coordinates (x, y) when orthogonal coordinates in the film plane are displayed as (x, y). Can be represented.
The elevation of the surface irregularity shape can be obtained from the three-dimensional information of the surface shape measured by an apparatus such as a confocal microscope, an interference microscope, an atomic force microscope (AFM) or the like. The horizontal resolution required for the measuring instrument is at least 5 μm or less, preferably 2 μm or less, and the vertical resolution is at least 0.1 μm or less, preferably 0.01 μm or less. Examples of the non-contact three-dimensional surface shape / roughness measuring apparatus suitable for this measurement include New View 5000 series (manufactured by Zygo Corporation), three-dimensional microscope PL μ2300 (manufactured by Sensofar), and the like. Since the resolution of the power spectrum of the altitude needs to be 0.005 μm ⁻¹ or less, the measurement area is preferably at least 200 μm × 200 μm, and more preferably 500 μm × 500 μm or more.
Next, a method for obtaining an altitude power spectrum from a two-dimensional function h (x, y) will be described. First, a two-dimensional function H (f _x , f _y ) is obtained from the two-dimensional function h (x, y) by a two-dimensional Fourier transform defined by equation (1).

Where f _x and f _y are frequency of x and y directions, respectively, with the dimension of reciprocal length. Further, in Expression (1), π is a pi and i is an imaginary unit. By squaring the absolute value of the obtained two-dimensional function H (f _x , f _y ), the two-dimensional power spectrum I (f _x , f _y ) can be obtained by equation (2).

The two-dimensional power spectrum I _{(f x,} f _y) represents the spatial frequency distribution of the surface irregularities of the antiglare film has. Since the antiglare film is isotropic, the two-dimensional function I (f _x , f _y ) representing the two-dimensional power spectrum of the elevation of the surface irregularity shape depends only on the distance f from the origin (0, 0). It can be represented by a one-dimensional function I (f). Next, a method of obtaining a two-dimensional function _{I _(f} x, f _y) from a one-dimensional function I (f). First, it displayed in polar coordinates based two-dimensional function I (f _{x, f} _y) is a two-dimensional power spectrum of the altitude of the equation (3).

Here, θ is a declination angle in Fourier space. The one-dimensional function I (f) can be obtained by calculating the rotational average of the two-dimensional function I (fcos θ, fsin θ) displayed in polar coordinates based on the equation (4). The one-dimensional function I (f) obtained from the rotating average of the two-dimensional function I (f _x , f _y ), which is a two-dimensional power spectrum at an altitude, is also referred to as a one-dimensional power spectrum I (f) below.

The antiglare film of the present invention has an intensity I (0.01) at a spatial frequency of 0.01 μm ⁻¹ and a spatial frequency of 0.02 μm ^{− of the} one-dimensional power spectrum I (f) calculated from the elevation of the surface uneven shape. the intensity I (0.02) in ^1, and the intensity I (0.1) in the spatial frequency 0.1 [mu] m ^-1 is characterized in that both are within the specified range.
Hereinafter, the method for obtaining the two-dimensional power spectrum of the elevation of the surface unevenness of the antiglare film will be described more specifically. The three-dimensional information of the surface shape actually measured by the above confocal microscope, interference microscope, atomic force microscope or the like is generally obtained as discrete values, that is, elevations corresponding to a large number of measurement points. FIG. 4 is a schematic diagram showing a state where functions h (x, y) representing altitude are obtained discretely. As shown in FIG. 4, the orthogonal coordinates in the film plane are displayed as (x, y), and on the film projection plane 3, a line divided every Δx in the x-axis direction and a division every Δy in the y-axis direction. When the measured line is indicated by a broken line, in the actual measurement, the elevation of the surface uneven shape is obtained as a discrete elevation value for each area Δx × Δy divided by each broken line on the film projection surface 3.
The number of elevation values obtained is determined by the measurement range and Δx and Δy. As shown in FIG. 4, when the measurement range in the x-axis direction is X = MΔx and the measurement range in the y-axis direction is Y = NΔy, The number of elevation values to be obtained is M × N.
As shown in FIG. 4, when the coordinates of the point of interest A on the film projection surface 3 are (mΔx, nΔy) [where m is 0 or more and M−1 or less, and n is 0 or more and N−1 or less]. The elevation of the point P on the film surface corresponding to the point of interest A can be expressed as h (mΔx, nΔy).
Here, the measurement intervals Δx and Δy depend on the horizontal resolution of the measuring device, and in order to accurately evaluate the surface unevenness shape, both Δx and Δy are preferably 5 μm or less, and preferably 2 μm or less. Is more preferable. Further, as described above, the measurement ranges X and Y are both preferably 200 μm or more, and more preferably 500 μm or more.
As described above, in actual measurement, the function representing the elevation of the surface irregularity shape is obtained as a discrete function h (x, y) having M × N values. Therefore, the two-dimensional function H (f _x , f _y ) obtained by the two-dimensional Fourier transform of the two-dimensional function h (x, y) of the elevation of the surface uneven shape is also a discrete Fourier obtained by discretely calculating the expression (1). By conversion, it is obtained as a discrete function as shown in Equation (5).

Here, j in the formula (5) is an integer of −M / 2 or more and M / 2 or less, and k is an integer of −N / 2 or more and N / 2 or less. Δf _x and Δf _y are frequency intervals in the x direction and the y direction, respectively, and are defined by Expression (6) and Expression (7).

The two-dimensional power spectrum I (f _x , f _y ) is obtained as shown in equation (8) by squaring the absolute value of the discrete function H (f _x , f _y ) obtained by equation (5).

The reason why | H (jΔf _x , kΔf _y ) | ² in equation (8) is divided by MNΔxΔy is to normalize that the integration range differs depending on the measurement area in the actual measurement.
The two-dimensional power spectrum I (f _x , f _y ) obtained as a discrete function also represents the spatial frequency distribution of the uneven surface shape of the antiglare film. Further, since the antiglare film is isotropic, two-dimensional discrete function I (f _{x, f} _y) representing the two-dimensional power spectrum of the altitude of the surface unevenness shape only at a distance f from the origin (0, 0) It can be expressed by a dependent one-dimensional discrete function I (f). When obtaining the one-dimensional discrete function I (f) from the two-dimensional discrete function I (f _x , f _y ), the rotational average may be calculated in the same manner as in the equation (4). Two-dimensional discrete function _{I _(f} x, f _y) discrete rotational average can be calculated by Equation (9).

Here, when M ≧ N, l is an integer from 0 to N / 2, and when M <N, l is an integer from 0 to M / 2. Δf is the distance from the origin, and Δf = (Δf _x + Δf _y ) / 2. Θ (x) is a heavy side function defined by the equation (10). f _jk is the distance from the origin at (j, k), and is calculated by equation (11).

The calculation shown in Formula (9) is demonstrated using FIG. The function Θ (f _jk − (l−1 / 2) Δf) is 0 when f _jk is less than (l−1 / 2) Δf, and 1 when f _jk is equal to or greater than (l−1 / 2) Δf. The function Θ (f _jk − (l + 1/2) Δf) is 0 when f _jk is less than (l + 1/2) Δf, and 1 when f _jk is equal to or greater than (l + 1/2) Δf. 9) _{Θ (f jk - (l-} 1/2) Δf) -Θ (f jk - (l + 1/2) Δf) _{is, f jk} is (l-1/2) Δf or more (l-1/2 ) 1 only when it is less than Δf, 0 otherwise. Here, since f _jk is a distance from the origin O (f _x = 0, f _y = 0) in the frequency space, the denominator of the equation (9) has a distance f _jk from the origin O of (l−1 / 2) The number of all points (black circle points in FIG. 5) located at or above Δf and below (l + 1/2) Δf is calculated. In addition, the numerator of the formula (9) has the distance f _jk from the origin O of I (f _x , f _y ) of all points located at (l−1 / 2) Δf or more and less than (l + 1/2) Δf. The total value (the total value of I (f _x , f _y ) at the black circle points in FIG. 5) is calculated.
In general, the one-dimensional power spectrum obtained by the above-described method includes noise in measurement. To determine the one-dimensional power spectrum here, in order to eliminate the influence of this noise, the elevation of the surface irregularities at multiple locations on the antiglare film is measured, and the one-dimensionality obtained from the elevation of each surface irregularity shape. The average value of the power spectrum is preferably used as the one-dimensional power spectrum I (f). The number of locations for measuring the elevation of the surface unevenness on the antiglare film is preferably 3 or more, more preferably 5 or more.
FIG. 6 shows I (f) of the one-dimensional power spectrum of the elevation of the surface unevenness obtained in this way. The one-dimensional power spectrum I (f) in FIG. 6 is an average of the one-dimensional power spectra obtained from the elevations of the surface irregularities at five different locations on the antiglare film.
In the antiglare film of the present invention, the intensity I (0.01) at a spatial frequency of 0.01 μm ⁻¹ of the one-dimensional power spectrum I (f) calculated from the elevation of the surface uneven shape is 2 μm ⁴ or more and 10 μm ⁴ or less. The intensity I (0.02) at a spatial frequency of 0.02 μm ⁻¹ is 0.1 μm ⁴ or more and 1.5 μm ⁴ or less, and the intensity I (0.1) at a spatial frequency of 0.1 μm ⁻¹ is 0.0001 μm ^4. It is 0.01 μm ⁴ or more. Here, since the one-dimensional power spectrum I (f) is obtained as a discrete function, the intensity I (f ₁ ) at a specific spatial frequency f ₁ can be obtained by interpolation as shown in the equation (12). .

The anti-glare film of the present invention prevents the occurrence of whitish and glare well by synergistic effects with the haze and reflectance ratio described later by setting the intensity at the specific spatial frequency within a predetermined range. While exhibiting excellent anti-glare properties. In order to express such an effect more, the strength I (0.01) is preferably 2.5 μm ⁴ or more and 9 μm ⁴ or less, more preferably 3 μm ⁴ or more and 8 μm ⁴ or less. Similarly, the intensity I (0.02) is preferably 0.2 [mu] m ⁴ or more 1.2 [mu] m ⁴ or less, 0.25 [mu] m ⁴ or more 1 [mu] m ⁴ further preferably less intensity I (0.1) is, 0.0003Myuemu ⁴ or more 0.0075Myuemu ⁴ or less, and further preferably 0.0005 ⁴ or 0.005 .mu.m ⁴ or less.
When I (0.01) is less than the above range, a swell of about 100 μm (corresponding to 0.01 μm ⁻¹ in spatial frequency) contributing to the antiglare effect when the antiglare film is observed obliquely. Since it will be small, anti-glare property will become inadequate. When I (0.01) exceeds the above range, the undulation with a period of about 100 μm becomes too large, the surface uneven shape of the antiglare film becomes rough, and haze tends to increase, which is not preferable.
When I (0.02) is less than the above range, a swell of a period of about 50 μm (corresponding to 0.02 μm ⁻¹ in spatial frequency) contributing to the antiglare effect when the antiglare film is observed from the front. Since it will be small, anti-glare property will become inadequate. When I (0.02) exceeds the above range, the undulation with a period of about 50 μm becomes too large and glare occurs.
When I (0.1) is less than the above range, the short-period uneven shape of about 10 μm (corresponding to 0.1 μm ⁻¹ in spatial frequency) is very small, and the surface uneven shape of the antiglare film is long. Since it will be formed only from the uneven shape of a period and the surface texture of an anti-glare film becomes coarse, it is not preferable. When I (0.1) exceeds the above range, scattering due to surface irregularities having a short period of about 10 μm becomes strong, and whitening tends to occur.
[All haze, surface haze]
The antiglare film of the present invention exhibits antiglare properties and prevents whitishness, so that the total haze with respect to normal incident light is in the range of 0.1% to 3%, and the surface haze is 0.1. % Or more and 2% or less. The total haze of the antiglare film can be measured by a method based on the method described in JIS K7136. An image display device in which an antiglare film having a total haze or surface haze of less than 0.1% is not preferable because it does not exhibit sufficient antiglare properties. Further, when the total haze exceeds 3% or the surface haze exceeds 2%, the antiglare film is not preferable because the image display device on which the antiglare film is disposed will generate whiteness. . In addition, such an image display device has a disadvantage that the contrast becomes insufficient.
The lower the internal haze obtained by subtracting the surface haze from the total haze, the better. Specifically, it is preferably 2.5% or less. The image display apparatus in which the antiglare film having the internal haze exceeding 2.5% has a tendency to decrease the contrast.
[Transmission definition Tc, reflection definition Rc (45), and reflection definition Rc (60)]
The antiglare film of the present invention preferably has a transmission clarity sum Tc of 375% or more determined under the following measurement conditions. The sum Tc of transmitted sharpness is calculated by measuring the image sharpness using an optical comb having a predetermined width by a method based on JIS K 7105, and calculating the sum thereof. Specifically, five types of optical combs are used in which the ratio of the width of the dark part to the bright part is 1: 1 and the width is 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm. The image definition is then measured, and the total is obtained as Tc. When the antiglare film having a Tc of less than 375% is disposed in a higher-definition image display device, glare may easily occur. The upper limit of Tc is selected in the range of 500% or less, which is the maximum value. However, if this Tc is too high, an image display device in which the antiglare property from the front tends to decrease can be obtained. Preferably there is.
The antiglare film of the present invention preferably has a reflection definition Rc (45) measured by incident light having an incident angle of 45 ° of 180% or less. The reflection definition Rc (45) is measured by a method based on JIS K 7105, as in the case of Tc. Among the five types of optical combs, the width is 0.25 mm, 0.5 mm, The image sharpness measured using four types of optical combs of 1.0 mm and 2.0 mm is measured, and the sum thereof is obtained as Rc (45). When Rc (45) is 180% or less, an image display device in which such an antiglare film is disposed is preferable because the antiglare property when observed from the front and oblique directions becomes better. The lower limit of Rc (45) is not particularly limited, but is preferably 80% or more, for example, in order to satisfactorily suppress the occurrence of whitishness and glare.
The antiglare film of the present invention preferably has a reflection definition Rc (60) of 240% or less as measured with incident light having an incident angle of 60 °. The reflection definition Rc (60) is measured by a method based on the same JIS K 7105 as the reflection definition Rc (45) except that the incident angle is changed. When Rc (60) is 240% or less, an image display device in which the antiglare film is disposed is preferable because the antiglare property when observed obliquely becomes better. The lower limit of Rc (60) is not particularly limited, but is preferably, for example, 150% or more in order to better suppress the occurrence of whitish or glare.
[Production Method of Antiglare Film of the Present Invention]
The antiglare film of the present invention is produced, for example, as follows. The first method is to prepare a fine unevenness forming mold in which a surface unevenness shape based on a predetermined pattern is formed on a molding surface, transfer the shape of the uneven surface of the mold to a transparent support, In this method, the transparent support on which the shape of the surface is transferred is peeled off from the mold. The second method is to prepare a composition containing fine particles, a resin (binder) and a solvent, in which the fine particles are dispersed in a resin solution, apply the composition onto a transparent support, and dry as necessary. This is a method of curing the coating film (coating film containing fine particles) formed in (1). In the second method, the coating film thickness and the aggregation state of the fine particles are adjusted according to the composition of the composition, the drying conditions of the coating film, etc., thereby exposing the fine particles to the surface of the coating film, and transparent random irregularities. Form on the support. From the viewpoint of production stability and production reproducibility of the antiglare film, it is preferable to produce the antiglare film of the present invention by the first method.
Here, the 1st method preferable as a manufacturing method of the anti-glare film of this invention is explained in full detail.
In order to accurately form a surface uneven-shaped antiglare layer having the above-described properties, a prepared fine unevenness forming mold (hereinafter sometimes abbreviated as “mold”) is important. More specifically, the surface irregularity shape of the mold (hereinafter, sometimes referred to as “mold irregular surface”) is formed based on a predetermined pattern, and this predetermined pattern is the one-dimensional power spectrum. the ratio of the intensity gamma (0.02) in the intensity gamma (0.01) and the spatial frequency 0.02 [mu] m ^-1 in the spatial frequency ^{0.01μm -1 Γ (0.02) / Γ} (0.01) 0.05 or 1.2 or less, the ratio gamma (0.1) of the intensity in the intensity gamma (0.01) and the spatial frequency 0.1 [mu] m ^-1 in the spatial frequency ^{0.01μm -1 Γ (0.1) / Γ} ( 0.01) is preferably 4 or more and 25 or less. Here, the “pattern” means image data for forming the surface uneven shape of the antiglare layer of the antiglare film, a mask having a light transmitting part and a light shielding part, etc. ".
First, a method for defining a pattern for forming the surface irregularity shape of the antiglare layer of the antiglare film of the present invention will be described.
A method for obtaining a two-dimensional power spectrum of a pattern will be described, for example, when the pattern is image data. First, after converting the image data into binary image data of two gradations, the gradation is expressed by a two-dimensional function g (x, y). The obtained two-dimensional function g (x, y) is Fourier-transformed as shown in the following formula (13) to calculate a two-dimensional function G (f _x , f _y ), and as shown in the following formula (14), the resulting two-dimensional function _{G _(f} x, f _y) by squaring the absolute value of the obtained two-dimensional power spectrum _{_{Γ (f x, f y)}} . Here, x and y represent orthogonal coordinates in the image data plane. Further, f _x and f _y respectively represent the frequencies of the x and y directions, with the dimensions of the reciprocal of length.

In Expression (13), π is a pi, and i is an imaginary unit.

This two-dimensional power spectrum Γ (f _x , f _y ) represents the spatial frequency distribution of the pattern. Usually, since it is calculated | required that an anti-glare film is isotropic, the pattern for anti-glare film manufacture of this invention also becomes isotropic. Therefore, two-dimensional function representing the two-dimensional power spectrum of the pattern gamma (f _{x, f} _y) can be represented by one-dimensional functions that depend only on the distance f from the origin (0,0) Γ (f). Next, a method of obtaining a two-dimensional function Γ _{_(f} x, f _y) a one-dimensional function from a gamma (f). First, two-dimensional function is a two-dimensional power spectrum of the gradation pattern Γ a (f _{x, f} _y) is displayed in polar coordinates by the equation (15).

Here, θ is a declination angle in Fourier space. The one-dimensional function Γ (f) can be obtained by calculating the rotational average of the two-dimensional function Γ (fcosθ, fsinθ) displayed in polar coordinates as shown in equation (16). Two-dimensional function Γ _{(f x,} f _y) is a two-dimensional power spectrum of the gradation pattern one-dimensional function is determined from the rotational mean of gamma and (f), also referred to as a one-dimensional power spectrum gamma (f) in the following.

To obtain anti-glare film of the present invention accurately the intensity in the intensity gamma (0.01) and the spatial frequency 0.02 [mu] m ^-1 in the spatial frequency 0.01 [mu] m ^-1 of the one-dimensional power spectrum of the pattern gamma (0. 02) ratio Γ (0.02) / Γ (0.01) is 0.05 or more and 1.2 or less, and the intensity Γ (0.01) and the spatial frequency 0.1 μm at the spatial frequency 0.01 μm ⁻¹ . The ratio Γ (0.1) / Γ (0.01) of the intensity Γ (0.1) at ⁻¹ is preferably 4 or more and 25 or less.
When obtaining a two-dimensional power spectrum of a pattern, the two-dimensional function g (x, y) of gradation is usually obtained as a discrete function. In that case, a two-dimensional power spectrum may be calculated by discrete Fourier transform. The one-dimensional power spectrum of the pattern is obtained in the same manner from the two-dimensional power spectrum of the pattern.
In addition, in order to make the obtained surface unevenness shape a uniform and continuous curved surface, the average value of the two-dimensional function g (x, y) is the maximum value of the two-dimensional function g (x, y) and the two-dimensional function. It is preferably 30 to 70% of the difference from the minimum value of g (x, y). When the uneven surface of the mold is manufactured by a lithography method, the two-dimensional function g (x, y) is a pattern aperture ratio. With respect to the case where the mold uneven surface is manufactured by a lithography method, the pattern aperture ratio here is defined. The aperture ratio when the resist used in the lithography method is a positive resist means the ratio of the exposed area to the entire surface area of the coating film when image data is drawn on the coating film of the positive resist. On the other hand, the aperture ratio when the resist used in the lithography method is a negative resist means the ratio of the unexposed area to the entire surface area of the coating film when image data is drawn on the coating film of the negative resist. The aperture ratio when the lithography method is batch exposure means the ratio of the light-transmitting portion of the mask having the light-transmitting portion and the light-shielding portion.
In the antiglare film of the present invention, each of the intensity ratios Γ (0.02) / Γ (0.01) and Γ (0.1) / Γ (0.01) of the one-dimensional power spectrum of the pattern is In this range, a desired mold can be manufactured, and the first method using the mold can be manufactured.
In order to create a pattern of a one-dimensional power spectrum having such an intensity ratio, a random brightness distribution whose density is determined by a pattern created by randomly arranging dots or a random number or a pseudo-random number generated by a computer is used. A pattern (preliminary pattern) having the predetermined spatial frequency range is removed from the preliminary pattern. In order to remove components in this specific spatial frequency range, the preliminary pattern may be passed through a band pass filter.
In order to manufacture an anti-glare film having an anti-glare layer having a surface uneven shape formed based on a predetermined pattern, a mold uneven surface for transferring the surface uneven shape formed based on the predetermined pattern to a transparent support. Is manufactured. The first method using such a mold is an embossing method characterized by producing an antiglare layer on a transparent support.
Examples of the embossing method include a photoembossing method using a photocurable resin and a hot embossing method using a thermoplastic resin. Of these, the photo-embossing method is preferable from the viewpoint of productivity.
In the photo-embossing method, a photocurable resin layer is formed on a transparent support (the surface of the transparent support), and the photocurable resin layer is cured while being pressed against the uneven surface of the mold. This is a method of transferring the shape of the uneven surface of the mold to the photocurable resin layer. Specifically, in a state in which a photocurable resin layer formed by applying a photocurable resin on a transparent support is in close contact with the uneven surface of the mold, light is emitted from the transparent support side (the light is photocurable). A photocurable resin (photocurable resin contained in the photocurable resin layer) is cured by irradiating with a resin that can cure the resin, and then the cured photocurable resin layer is formed. The support is peeled from the mold. In the antiglare film obtained by such a production method, the cured photocurable resin layer becomes an antiglare layer. From the viewpoint of ease of production, an ultraviolet curable resin is preferable as the photocurable resin, and when the ultraviolet curable resin is used, ultraviolet light is used as the irradiation light (the ultraviolet curable resin is used as the photocurable resin). The embossing method using a functional resin is hereinafter referred to as “UV embossing method”). In order to produce an antiglare film integrated with a polarizing film, a polarizing film may be used as a transparent support, and the transparent support may be replaced with a polarizing film in the embossing method described here.
The kind of the ultraviolet curable resin used for the UV embossing method is not particularly limited, and an appropriate one can be used from commercially available resins according to the kind of transparent support to be used and the kind of ultraviolet light. Such an ultraviolet curable resin is a concept including a monomer (polyfunctional monomer), an oligomer and a polymer that are photopolymerized by ultraviolet irradiation, and a mixture thereof. In addition, a resin that can be cured even with visible light having a wavelength longer than that of ultraviolet rays can be used by using a combination of photoinitiators appropriately selected according to the type of the ultraviolet curable resin. A description of suitable examples of the ultraviolet curable resin will be given later.
As the transparent support used in the UV embossing method, for example, glass or plastic film can be used. Any plastic film can be used as long as it has appropriate transparency and mechanical strength. Specifically, for example, a transparent resin film made of cellulose acetate resin such as TAC (triacetyl cellulose); acrylic resin; polycarbonate resin; polyester resin such as polyethylene terephthalate; polyolefin resin such as polyethylene and polypropylene Is mentioned. These transparent resin films may be solvent cast films or extruded films.
The thickness of the transparent support is, for example, 10 to 500 μm, preferably 10 to 100 μm, and more preferably 10 to 60 μm. When the thickness of the transparent support is within this range, an antiglare film having sufficient mechanical strength tends to be obtained, and the image display device provided with the antiglare film is more unlikely to cause glare. .
On the other hand, in the hot embossing method, a transparent resin film formed of a thermoplastic resin is pressed against a mold uneven surface while being heated and softened, and the surface uneven shape of the mold uneven surface is transferred to the transparent resin film. Is the method. The transparent resin film used for the hot embossing method may be any material as long as it is substantially optically transparent. Specifically, examples include those exemplified as the transparent resin film used for the UV embossing method. Can do.
Next, a method for manufacturing a mold used for the embossing method will be described.
As for the mold manufacturing method, the molding surface of the mold can transfer the surface uneven shape formed based on the above-described predetermined pattern onto the transparent support (the surface uneven shape formed based on the predetermined pattern). In order to produce the anti-glare layer having an uneven surface with high accuracy and good reproducibility, a lithography method is preferred. Further, the lithography method includes [1] first plating step, [2] polishing step, [3] photosensitive resin film forming step, [4] exposure step, [5] development step, and [6]. It is preferable to include an etching step, a [7] photosensitive resin film peeling step, and an [8] second plating step.
FIG. 7 is a view schematically showing a preferred example of the first half of the mold manufacturing method. FIG. 7 schematically shows a cross section of the mold in each step. Hereafter, each process of the manufacturing method of the metal mold | die for anti-glare film manufacture of this invention is demonstrated in detail, referring FIG.
[1] First Plating Step First, a base material (mold base material) used for mold production is prepared, and copper plating is applied to the surface of the mold base material. Thus, by performing copper plating on the surface of the mold base, it is possible to improve the adhesion and gloss of chromium plating in the second plating step described later. Copper plating has a high covering property and a strong smoothing action, so that a flat and glossy surface can be formed by filling minute irregularities and voids of the mold base. Therefore, by performing copper plating on the mold substrate surface in this way, even if chromium plating is performed in the second plating step described later, it is caused by minute irregularities and voids existing on the substrate. The rough surface of the chrome plating that appears is eliminated, and the occurrence of fine cracks is reduced due to the high coverage of the copper plating. Therefore, even if a surface irregularity shape (fine irregularity surface shape) based on a predetermined pattern is created on the mold substrate molding surface, the influence of the surface (mold substrate) surface such as minute irregularities, voids, cracks, etc. Can be prevented sufficiently.
As copper used for the copper plating in the first plating step, pure copper metal or an alloy containing copper as a main component (copper alloy) may be used. Therefore, “copper” used for copper plating is a concept including copper and a copper alloy. The copper plating may be electrolytic plating or electroless plating, but the copper plating in the first plating step is preferably electrolytic plating. Furthermore, the preferable plating layer in the first plating step is not limited to a copper plating layer but may be a laminate of a copper plating layer and a plating layer made of a metal other than copper.
If the plating layer formed by applying copper plating on the surface of the mold base is too thin, the influence of the underlying surface (fine irregularities, voids, cracks, etc.) cannot be eliminated, so the thickness is 50 μm. The above is preferable. The upper limit of the plating layer thickness is not critical, but is preferably about 500 μm or less in consideration of cost and the like.
The mold base is preferably a base made of a metal material. Furthermore, from the viewpoint of cost, the metal material is preferably aluminum or iron. Further, from the viewpoint of convenience of handling the mold base, a lightweight aluminum base is particularly preferable as the mold base. In addition, aluminum and iron here do not need to be a pure metal, respectively, and may be an alloy containing aluminum or iron as a main component.
The shape of the base material for molds should just be an appropriate shape according to the manufacturing method of the anti-glare film of this invention. Specifically, it is selected from a flat substrate, a columnar substrate, a cylindrical (roll shape) substrate, and the like. When manufacturing the anti-glare film of this invention continuously, it is preferable in a metal mold | die being a roll shape. Such a mold is manufactured from a roll-shaped mold substrate.
[2] Polishing Step In the subsequent polishing step, the surface (plating layer) of the mold base that has been subjected to copper plating in the first plating step described above is polished. In the manufacturing method of the metal mold | die used for the manufacturing method of the anti-glare film of this invention, it is preferable to grind | polish to the state close | similar to a mirror surface through the said grinding | polishing process. Commercial products such as flat and roll-shaped substrates used as mold substrates are often subjected to machining such as cutting and grinding to achieve the desired accuracy. Fine processed marks remain on the substrate surface. Therefore, even if a plating (preferably copper plating) layer is formed by the first plating step, the processed marks may remain. Moreover, even if the plating in the first plating step is performed, the surface of the mold base is not always completely smooth. That is, even when the mold substrate having a surface with such deep processed marks remaining thereon is subjected to the steps [3] to [8] described later, the surface irregularity shape of the obtained mold surface is obtained. May differ from the surface uneven shape based on the predetermined pattern, or may include unevenness derived from the processed eyes. When an anti-glare film is produced using a mold having effects such as processing eyes remaining, the target optical characteristics such as anti-glare property cannot be sufficiently exhibited, and there is a possibility of unexpected influence.
The polishing method applied in the polishing step is not particularly limited, and a polishing method according to the shape and properties of the mold base material to be polished is selected. Specific examples of the polishing method applicable to the polishing step include a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method. Among these, as the mechanical polishing method, any of super finishing method, lapping, fluid polishing method, buff polishing method and the like can be used. Moreover, it is good also considering the surface of the base material for molds as a mirror surface by carrying out mirror surface cutting using a cutting tool in a grinding | polishing process. In this case, carbide tool, CBN tool, ceramic tool, diamond tool, etc. can be used as the material and shape of the cutting tool depending on the type (metal material) of the mold base material. From this point of view, it is preferable to use a diamond bite. The surface roughness after polishing is preferably 0.1 μm or less, and more preferably 0.05 μm or less, expressed as a centerline average roughness Ra based on JIS B 0601. When the center line average roughness Ra after polishing is larger than 0.1 μm, there is a possibility that the influence of the surface roughness remains on the mold uneven surface of the finally obtained mold. Further, the lower limit of the center line average roughness Ra is not particularly limited. Therefore, the lower limit may be determined from the viewpoint of processing time (polishing time) and processing cost in the polishing process.
[3] Photosensitive Resin Film Forming Step Next, the photosensitive resin film forming step will be described with reference to FIG.
In the photosensitive resin film forming step, a solution (photosensitive resin solution) in which a photosensitive resin is dissolved in a solvent is applied to the surface 41 of the mold base 40 subjected to the mirror polishing obtained in the above-described polishing step. A photosensitive resin film (resist film) is formed by heating and drying. FIG. 7 schematically shows a state in which the photosensitive resin film 50 is formed on the surface 41 of the mold base 40 (FIG. 7B).
As the photosensitive resin, conventionally known photosensitive resins can be used, and those already marketed as resists can be used as they are or after being purified by filtration or the like as necessary. For example, as a negative photosensitive resin having a property of curing a photosensitive part, a monomer or prepolymer of a (meth) acrylic acid ester having an acryloyl group or a methacryloyl group in a molecule, a mixture of bisazide and a diene rubber Polyvinyl cinnamate compounds and the like can be used. In addition, as a positive photosensitive resin having a property that a photosensitive portion is eluted by development and only an unexposed portion remains, a phenol resin type or a novolac resin type can be used. Such a positive or negative photosensitive resin can also be easily obtained from the market as a positive resist or a negative resist. Moreover, the photosensitive resin solution may contain various additives such as a sensitizer, a development accelerator, an adhesion modifier, and a coating property improver, if necessary. What mixed with the commercially available resist can also be used as a photosensitive resin solution.
In order to apply these photosensitive resin solutions to the surface 41 of the mold base 40, an optimum solvent is selected to form a smoother photosensitive resin film, and the photosensitive resin is dissolved in the solvent. -It is preferable to use a photosensitive resin solution obtained by dilution. Such a solvent is further selected depending on the type of the photosensitive resin and its solubility. Specifically, for example, a cellosolve solvent, a propylene glycol solvent, an ester solvent, an alcohol solvent, a ketone solvent, a highly polar solvent, or the like is selected. When a commercially available resist is used, an optimal resist may be selected and used as a photosensitive resin solution depending on the type of the solvent contained in the resist or by conducting an appropriate preliminary experiment.
The method of applying the photosensitive resin solution to the mirror-polished surface of the mold base is as follows: meniscus coating, fountain coating, dip coating, spin coating, roll coating, wire bar coating, air knife coating, blade coating, curtain The method is selected from known methods such as coating and ring coating according to the shape of the mold base. The thickness of the photosensitive resin film after coating is preferably in the range of 1 to 10 μm, more preferably in the range of 6 to 9 μm, as the thickness after drying.
[4] Exposure Step The subsequent exposure step is a step of transferring the target pattern to the photosensitive resin film 50 by exposing the photosensitive resin film 50 formed in the above-described photosensitive resin film forming step. is there. The light source used in the exposure process may be appropriately selected according to the photosensitive wavelength and sensitivity of the photosensitive resin contained in the photosensitive resin film. For example, the g-line (wavelength: 436 nm) and h-line (wavelength: high-pressure mercury lamp). 405 nm) or i-line (wavelength: 365 nm), semiconductor laser (wavelength: 830 nm, 532 nm, 488 nm, 405 nm, etc.), YAG laser (wavelength: 1064 nm), KrF excimer laser (wavelength: 248 nm), ArF excimer laser (wavelength: 193 nm), F2 excimer laser (wavelength: 157 nm), or the like can be used. The exposure method may be a batch exposure method using a mask corresponding to a target pattern, or a drawing method. As already described, the target pattern is the spatial frequency intensity ratio Γ (0.02) / Γ (0.01) and Γ (0.1) / Γ (0.01) of the one-dimensional power spectrum. Is set to a predetermined preferable range.
In the mold manufacturing method, it is preferable to expose the target pattern on the photosensitive resin film in a precisely controlled state in order to form the surface uneven shape of the mold with higher accuracy. In order to perform exposure in such a state, a target pattern is created as image data on a computer, and a pattern based on the image data is formed on the photosensitive resin film by laser light emitted from a computer-controlled laser head. It is preferable to draw (laser drawing). When performing laser drawing, a general-purpose laser drawing apparatus can be used, for example, for making a printing plate. As a commercially available product of such a laser lithography apparatus, for example, Laser Stream FX (manufactured by Sink Laboratory Co., Ltd.) and the like can be mentioned.
FIG. 7C schematically shows a state in which the pattern is exposed to the photosensitive resin film 50. When the photosensitive resin film 50 contains a negative photosensitive resin (for example, when a negative resist is used as the photosensitive resin solution), the exposed region 51 receives the exposure energy and receives the photosensitive resin. The crosslinking reaction proceeds and the solubility in the developer described later is lowered. Therefore, the unexposed area 52 in the development process is dissolved by the developer, and only the exposed area 51 remains on the surface of the base material to become the mask 60. On the other hand, when the photosensitive resin film 50 contains a positive photosensitive resin (for example, when a positive resist is used as the photosensitive resin solution), the exposed region 51 receives the exposure energy and is exposed to light. When the bonding of the functional resin is broken, it is easily dissolved in the developer described later. Therefore, the area 51 exposed in the development process is dissolved by the developer, and only the unexposed area 52 remains on the substrate surface to become the mask 60.
[5] Development Step In the development step, when the photosensitive resin film 50 contains a negative photosensitive resin, the unexposed region 52 is dissolved by the developer, and the exposed region 51 is a mold. The mask 60 remains on the substrate for use. On the other hand, when the photosensitive resin film 50 contains a positive photosensitive resin, only the exposed region 51 is dissolved by the developer, and the unexposed region 52 remains on the mold base. A mask 60 is obtained. In the mold base material in which the predetermined pattern is formed as the photosensitive resin film, the photosensitive resin film remaining on the mold base material acts as a mask in the etching process described later in the etching process.
About the developing solution used for a image development process, an appropriate thing can be selected according to the kind of photosensitive resin used among conventionally well-known things. For example, the developer includes inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; primary amines such as ethylamine and n-propylamine; Secondary amines such as n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylhydroxyethylammonium Quaternary ammonium compounds such as hydroxide; alkaline aqueous solutions such as cyclic amines such as pyrrole and pihelidine; and organic solvents such as xylene and toluene.
The development method in the development step is not particularly limited, and immersion development, spray development, brush development, ultrasonic development and the like can be used.
FIG. 7D schematically shows a state after the development process is performed using a negative type photosensitive resin. In FIG. 7D, the unexposed region 52 is dissolved by the developer, and only the exposed region 51 remains on the substrate surface, and the photosensitive resin film in this region becomes the mask 60. FIG. 7E schematically shows a state after the development process is performed using a positive type photosensitive resin. In FIG. 7E, the exposed region 51 is dissolved by the developer, and only the unexposed region 52 remains on the substrate surface, and the photosensitive resin film in this region becomes the mask 60.
[6] Etching process The etching process is mainly in a region without a mask on the surface of the mold base using the photosensitive resin film remaining on the surface of the mold base as a mask after the development process described above. This is a step of etching the plating layer.
FIG. 8 is a diagram schematically showing a preferred example of the latter half of the mold manufacturing method. FIG. 8A schematically shows a state after the plating layer mainly having no mask is etched by the etching process. The plating layer under the mask 60 is not etched because the photosensitive resin film functions as the mask 60, but the etching from the region 45 without the mask proceeds with the progress of etching. Therefore, in the vicinity of the boundary between the region with the mask 60 and the region 45 without the mask, the plating layer under the mask 60 is also etched. Thus, the etching of the plating layer under the mask 60 in the vicinity of the boundary between the region with the mask 60 and the region 45 without the mask is called side etching.
Etching treatment in the etching step is usually performed using an etching solution such as ferric chloride (FeCl ₃ ) solution, cupric chloride (CuCl ₂ ) solution, alkaline etching solution (Cu (NH ₃ ) ₄ Cl ₂ ), This is mainly performed by corroding a plating layer (metal surface) in a region where the mask 60 is not provided on the surface of the mold base. As the etching treatment, a strong acid such as hydrochloric acid or sulfuric acid can be used as an etching solution. When the plating layer is formed by electrolytic plating, reverse electrolytic etching is performed by applying a potential opposite to that at the time of electrolytic plating. Etching treatment can also be performed using. The surface irregularities formed on the mold base material when the etching process is performed are the constituent material (metal material) or plating layer type of the mold base material, the type of photosensitive resin film, and the etching process. Since it differs depending on the type of etching process, etc., it cannot be generally stated. However, when the etching amount is 10 μm or less, the etching is performed approximately isotropically from the surface of the mold substrate in contact with the etching solution. The etching amount here is the thickness of the plating layer that is scraped off by etching.
The etching amount in the etching step is preferably 1 to 20 μm, more preferably 1 to 8 μm, and further preferably 3 to 6 μm. When the etching amount is less than 1 μm, almost no surface unevenness is formed on the mold, and the mold has a substantially flat surface. Therefore, even if an antiglare film is produced using the mold, it is necessary. The antiglare film has almost no surface irregularity. In an image display device in which such an antiglare film is disposed, sufficient antiglare properties are not exhibited. Moreover, when the etching amount is too large, the finally obtained mold uneven surface tends to have a large uneven height difference. Even if an antiglare film is produced using the mold, the image display device provided with the antiglare film may not be able to sufficiently prevent the occurrence of whitening. The etching process in the etching process may be performed by one etching process, or the etching process may be performed in two or more times. Here, when the etching process is performed twice or more, the total etching amount in the two or more etching processes is preferably 1 to 20 μm.
[7] Photosensitive resin film peeling step The subsequent photosensitive resin film peeling step is a step of acting as a mask 60 in the etching step to remove the photosensitive resin film remaining on the mold substrate. It is preferable to completely remove the photosensitive resin film remaining on the mold base. In the photosensitive resin film peeling step, it is preferable to dissolve the photosensitive resin film using a peeling solution. As the stripper, those prepared by changing the concentration and pH of the developer exemplified as the developer can be used. Or the same thing as the developing solution used at the image development process is used, and the photosensitive resin film can also be peeled by changing temperature, immersion time, etc. with the image development process. In the photosensitive resin film peeling step, the contact method (peeling method) between the peeling liquid and the mold substrate is not particularly limited, and immersion peeling, spray peeling, brush peeling, ultrasonic peeling, and the like can be used.
FIG. 8B schematically shows a state where the photosensitive resin film used as the mask 60 in the etching process is completely dissolved and removed by the photosensitive resin film peeling process. The first surface uneven shape 46 is formed on the surface of the mold base by the mask 60 made of the photosensitive resin film and the etching process.
[8] Second plating step The final stage of the mold production is a second step in which plating (preferably, chromium plating described later) is performed on the surface of the mold substrate that has undergone the steps [6] and [7]. It is a plating process. By performing the second plating step, the uneven surface shape 46 of the mold base can be blunted, and the mold surface can be protected by the plating. Hereinafter, dulling the uneven surface shape of the mold base is referred to as “shape blunting”. In FIG. 8 (c), the surface uneven shape is blunted by forming the chromium plating layer 71 on the first surface uneven shape 46 formed by the etching process as described above (mold uneven surface 70). Shows the state.
The plating layer formed by the second plating step is preferably chromium plating in that it has gloss, high hardness, a low friction coefficient, and good release properties. Among the chromium platings, chromium plating that expresses good gloss, so-called glossy chromium plating or decorative chromium plating, is particularly preferable. Chromium plating is usually carried out by electrolysis, and as the plating bath, an aqueous solution containing chromic anhydride (CrO ₃ ) and a small amount of sulfuric acid is used as the plating solution. By adjusting the current density and electrolysis time, the thickness of the chromium plating layer can be controlled.
Thus, the metal mold | die for glare-proof film manufacture of this invention is obtained by performing the metal plating in a 2nd plating process, Preferably chromium plating. By performing chrome plating on the surface irregularities on the surface of the mold substrate after the etching treatment, the mold can be blunted and a mold whose surface hardness is increased can be obtained. In this case, the greatest factor in controlling the degree of shape blunting is the thickness of the chromium plating layer. When the thickness is small, the degree of shape blunting becomes insufficient, and the antiglare film obtained using such a mold has a ratio R (40) of the reflectance R (30) and the reflectance R (40). ) / R (30) may exceed 0.0025. On the other hand, if the thickness of the chromium plating layer is too thick, the ratio R (40) / R (30) will be less than 0.00001. The inventors of the present invention provide an antiglare film for sufficiently preventing the occurrence of whitish and obtaining an image display device having an excellent antiglare property, so that the thickness of the chromium plating layer is within a predetermined range. Has been found to be effective. That is, the thickness of the chromium plating layer is preferably in the range of 6 to 15 μm, and more preferably in the range of 8 to 11 μm.
The chromium plating layer formed in the second plating step is preferably formed so as to have a Vickers hardness of 800 or more, and more preferably 1000 or more. When the chrome plating layer has a Vickers hardness of less than 800, when the antiglare film is produced using the mold, the durability of the mold tends to decrease.
Below, the said photoembossing method preferable as a method for manufacturing the anti-glare film of this invention is demonstrated. As described above, the UV embossing method is particularly preferable as the photoembossing method. Here, the embossing method using an active energy ray-curable resin will be specifically described.
In order to continuously produce the antiglare film of the present invention, when the antiglare film of the present invention is produced by the photoembossing method, the following steps are performed:
[P1] A coating process in which a coating liquid containing an active energy ray-curable resin is coated on a transparent support that is continuously conveyed to form a coating layer, and [P2] a coating layer. It is preferable to include a main curing step of irradiating active energy rays from the transparent support side with the surface of the mold pressed against the surface of the mold.
In addition, when producing the antiglare film of the present invention by the photoembossing method,
[P3] After the coating step [P1] and before the curing step [P2], including a preliminary curing step of irradiating active energy rays to both end regions in the width direction of the coating layer. More preferred.
Hereafter, each process is demonstrated in detail, referring drawings. FIG. 9 is a diagram schematically showing a preferred example of a production apparatus used in the method for producing an antiglare film of the present invention. The arrow in FIG. 9 shows the conveyance direction of a film, or the rotation direction of a roll.
[P1] Coating process In the coating process, a coating liquid containing an active energy ray-curable resin is coated on a transparent support to form a coating layer. In the coating process, for example, as shown in FIG. 9, a coating liquid containing an active energy ray-curable resin composition is applied in the coating zone 83 to the transparent support 81 that is fed from the feed roll 80. .
Coating of the coating liquid on the transparent support 81 can be performed by, for example, a gravure coating method, a micro gravure coating method, a rod coating method, a knife coating method, an air knife coating method, a kiss coating method, a die coating method, or the like. .
(Transparent support)
The transparent support 81 only needs to be translucent, and for example, glass or plastic film can be used. The plastic film only needs to have appropriate transparency and mechanical strength. Specifically, any of those already exemplified as the transparent support for use in the UV embossing method can be used. Further, in order to continuously produce the antiglare film of the present invention by the photoembossing method, an appropriate flexibility is obtained. Those having sex are selected.
For the purpose of improving the coating property of the coating liquid and improving the adhesion between the transparent support and the coating layer, the surface of the transparent support 81 (surface on the coating layer side) may be subjected to various surface treatments. Good. Examples of the surface treatment include corona discharge treatment, glow discharge treatment, acid surface treatment, alkali surface treatment, and ultraviolet irradiation treatment. Further, another layer such as a primer layer may be formed on the transparent support 81, and a coating solution may be applied on the other layer.
Moreover, when manufacturing what was integrated with the polarizing film as an anti-glare film of this invention, in order to improve the adhesiveness of a transparent support and a polarizing film, the surface (coating layer and Is preferably hydrophilized by various surface treatments. This surface treatment may be performed after the production of the antiglare film.
(Coating fluid)
The coating liquid contains an active energy ray-curable resin and usually further contains a photopolymerization initiator (radical polymerization initiator). If necessary, it may contain various additives such as translucent fine particles, solvents such as organic solvents, leveling agents, dispersants, antistatic agents, antifouling agents, and surfactants.
(1) Active energy ray curable resin As an active energy ray curable resin, what contains a polyfunctional (meth) acrylate compound can be used preferably, for example. The polyfunctional (meth) acrylate compound is a compound having at least two (meth) acryloyloxy groups in the molecule. Specific examples of the polyfunctional (meth) acrylate compound include, for example, ester compounds of polyhydric alcohol and (meth) acrylic acid, urethane (meth) acrylate compounds, polyester (meth) acrylate compounds, epoxy (meth) acrylate compounds, and the like. And a polyfunctional polymerizable compound containing two or more (meth) acryloyl groups.
Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, polypropylene glycol, propanediol, butanediol, and pentanediol. , Hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, 2,2'-thiodiethanol, divalent alcohols such as 1,4-cyclohexanedimethanol; trimethylolpropane, glycerol, pentaerythritol , Trihydric or higher alcohols such as diglycerol, dipentaerythritol and ditrimethylolpropane.
Specific examples of esterified products of polyhydric alcohol and (meth) acrylic acid include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and neopentyl glycol. Di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, 1,6-hexanediol di (meth) acrylate, tetramethylolmethanetetra ( (Meth) acrylate, pentaglycerol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol tri (meth) acrylate, di Pentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate.
Examples of the urethane (meth) acrylate compound include a urethanization reaction product of an organic isocyanate having a plurality of isocyanate groups in one molecule and a (meth) acrylic acid derivative having a hydroxyl group. Examples of organic isocyanates having a plurality of isocyanate groups in one molecule include two isocyanates in one molecule such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and dicyclohexylmethane diisocyanate. Organic isocyanate having a group, organic isocyanate having three isocyanate groups in one molecule obtained by subjecting these organic isocyanates to isocyanurate modification, adduct modification, biuret modification, and the like. Examples of the (meth) acrylic acid derivative having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2- Examples include hydroxy-3-phenoxypropyl (meth) acrylate and pentaerythritol triacrylate.
A preferable polyester (meth) acrylate compound is a polyester (meth) acrylate obtained by reacting a hydroxyl group-containing polyester with (meth) acrylic acid. The hydroxyl group-containing polyester preferably used is a hydroxyl group-containing polyester obtained by an esterification reaction of a polyhydric alcohol, a carboxylic acid, a compound having a plurality of carboxyl groups, and / or an anhydride thereof. Examples of the polyhydric alcohol include the same compounds as those described above. Moreover, bisphenol A etc. are mentioned as phenols other than a polyhydric alcohol. Examples of the carboxylic acid include formic acid, acetic acid, butyl carboxylic acid, benzoic acid and the like. The compounds having a plurality of carboxyl groups and / or anhydrides thereof include maleic acid, phthalic acid, fumaric acid, itaconic acid, adipic acid, terephthalic acid, maleic anhydride, phthalic anhydride, trimellitic acid, cyclohexanedicarboxylic anhydride Thing etc. are mentioned.
Among the polyfunctional (meth) acrylate compounds as described above, hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meta) from the viewpoint of improving the strength of the cured product and availability. ) Ester compounds such as acrylate, tripropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate; hexamethylene diisocyanate and 2-hydroxyethyl Adduct of (meth) acrylate; adduct of isophorone diisocyanate and 2-hydroxyethyl (meth) acrylate; of tolylene diisocyanate and 2-hydroxyethyl (meth) acrylate Adducts; adduct adduct modified isophorone diisocyanate with 2-hydroxyethyl (meth) acrylate; and adducts with biuret of isophorone diisocyanate and 2-hydroxyethyl (meth) acrylate. Furthermore, these polyfunctional (meth) acrylate compounds can be used alone or in combination of two or more.
The active energy ray curable resin may contain a monofunctional (meth) acrylate compound in addition to the polyfunctional (meth) acrylate compound. Examples of the monofunctional (meth) acrylate compound include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-hydroxyethyl (meth) ) Acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, glycidyl (meth) acrylate, acryloylmorpholine , N-vinylpyrrolidone, tetrahydrofurfuryl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, acetyl (Meth) acrylate, benzyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxy (meth) acrylate, ethylene oxide modified phenoxy (meth) Acrylate, propylene oxide (meth) acrylate, nonylphenol (meth) acrylate, ethylene oxide modified (meth) acrylate, propylene oxide modified nonylphenol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, 2- (meth) acryloyloxyethyl-2- Such as hydroxypropyl phthalate, dimethylaminoethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, etc. Mention may be made of the data) acrylates. These compounds can be used alone or in combination of two or more.
Moreover, the active energy ray-curable resin may contain a polymerizable oligomer. By including the polymerizable oligomer, the hardness of the cured product can be adjusted. The polymerizable oligomer is, for example, the polyfunctional (meth) acrylate compound, that is, an ester compound of a polyhydric alcohol and (meth) acrylic acid, a urethane (meth) acrylate compound, a polyester (meth) acrylate compound, or an epoxy (meth). It can be an oligomer such as a dimer, trimer or the like such as an acrylate.
Other polymerizable oligomers include urethane (meth) acrylate oligomers obtained by reacting polyisocyanates having at least two isocyanate groups in the molecule with polyhydric alcohols having at least one (meth) acryloyloxy group. Can be mentioned. Examples of the polyisocyanate include hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and a polymer of xylylene diisocyanate. The polyhydric alcohol having at least one (meth) acryloyloxy group includes Hydroxyl group-containing (meth) acrylic acid ester obtained by esterification reaction of alcohol and (meth) acrylic acid, and as polyhydric alcohol, for example, 1,3-butanediol, 1,4-butanediol, 1,6 -Hexanediol, diethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane, glycerin, pentaerythritol, What is pentaerythritol. In this polyhydric alcohol having at least one (meth) acryloyloxy group, a part of the alcoholic hydroxyl group of the polyhydric alcohol is esterified with (meth) acrylic acid, and the alcoholic hydroxyl group is present in the molecule. It remains.
Furthermore, as another example of the polymerizable oligomer, a polyester (meta) obtained by reacting a compound having a plurality of carboxyl groups and / or an anhydride thereof with a polyhydric alcohol having at least one (meth) acryloyloxy group. ) Acrylate oligomers. Examples of the compound having a plurality of carboxyl groups and / or anhydrides thereof are the same as those described for the polyester (meth) acrylate of the polyfunctional (meth) acrylate compound. Examples of the polyhydric alcohol having at least one (meth) acryloyloxy group include those described for the urethane (meth) acrylate oligomer.
In addition to the polymerizable oligomers as described above, further examples of urethane (meth) acrylate oligomers are obtained by reacting isocyanates with hydroxyl groups of a hydroxyl group-containing polyester, a hydroxyl group-containing polyether or a hydroxyl group-containing (meth) acrylic acid ester. Compounds. The hydroxyl group-containing polyester preferably used is a hydroxyl group-containing polyester obtained by an esterification reaction of a polyhydric alcohol, a carboxylic acid, a compound having a plurality of carboxyl groups, and / or an anhydride thereof. Examples of the polyhydric alcohol and the compound having a plurality of carboxyl groups and / or anhydrides thereof are the same as those described for the polyester (meth) acrylate compound of the polyfunctional (meth) acrylate compound. The hydroxyl group-containing polyether preferably used is a hydroxyl group-containing polyether obtained by adding one or more alkylene oxides and / or ε-caprolactone to a polyhydric alcohol. The polyhydric alcohol may be the same as that which can be used for the hydroxyl group-containing polyester. Examples of the hydroxyl group-containing (meth) acrylic acid ester preferably used include the same as those described for the polymerizable oligomeric urethane (meth) acrylate oligomer. As the isocyanates, compounds having one or more isocyanate groups in the molecule are preferable, and divalent isocyanate compounds such as tolylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate are particularly preferable.
These polymerizable oligomer compounds can be used alone or in combination of two or more.
(2) Photoinitiator A photoinitiator can be suitably selected according to the kind of active energy ray applied to anti-glare film manufacture of this invention. Moreover, when using an electron beam as an active energy ray, the coating liquid which does not contain a photoinitiator may be used for anti-glare film manufacture of this invention.
Examples of the photopolymerization initiator include acetophenone photopolymerization initiator, benzoin photopolymerization initiator, benzophenone photopolymerization initiator, thioxanthone photopolymerization initiator, triazine photopolymerization initiator, and oxadiazole photopolymerization initiator. An initiator or the like is used. Examples of the photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2 '-Biimidazole, 10-butyl-2-chloroacridone, 2-ethylanthraquinone, benzyl, 9,10-phenanthrenequinone, camphorquinone, methyl phenylglyoxylate, titanocene compound and the like can also be used. The amount of the photopolymerization initiator used is usually 0.5 to 20 parts by weight, preferably 1 to 5 parts by weight with respect to 100 parts by weight of the active energy ray-curable resin.
The coating liquid may contain a solvent such as an organic solvent in order to improve the coating property on the transparent support. Examples of organic solvents include aliphatic hydrocarbons such as hexane, cyclohexane, and octane; aromatic hydrocarbons such as toluene and xylene; alcohols such as ethanol, 1-propanol, isopropanol, 1-butanol, and cyclohexanol; methyl ethyl ketone, methyl isobutyl Ketones such as ketone and cyclohexanone; esters such as ethyl acetate, butyl acetate and isobutyl acetate; glycols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether and propylene glycol monoethyl ether Ethers; ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, etc. Stealted glycol ethers; Cellsolves such as 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol; 2- (2-methoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethanol, 2- (2- It can be selected from carbitols such as butoxyethoxy) ethanol in consideration of viscosity and the like. These solvents may be used alone or as a mixture of several kinds as required. After coating, it is necessary to evaporate the organic solvent. Therefore, the boiling point is desirably in the range of 60 ° C to 160 ° C. The saturated vapor pressure at 20 ° C. is preferably in the range of 0.1 kPa to 20 kPa.
When a coating liquid contains a solvent, it is preferable to provide the drying process which evaporates a solvent and drys after the said coating process and before a 1st hardening process. Drying can be performed by passing the inside of the drying zone 84 through the transparent support body 81 provided with a coating layer, for example like the example shown by FIG. The drying temperature is appropriately selected depending on the solvent used and the type of transparent support. Generally, it is in the range of 20 ° C. to 120 ° C., but is not limited thereto. When there are a plurality of drying furnaces, the temperature may be changed for each drying furnace. The thickness of the coating layer after drying is preferably 1 to 30 μm.
Thus, a laminate in which the transparent support and the coating layer are laminated is formed.
[P2] Curing step This step is performed by irradiating the surface of the coating layer with active energy rays from the transparent support side in a state where the mold uneven surface (molded surface) having a desired surface uneven shape is pressed. It is a step of forming a cured resin layer on the transparent support by curing the work layer. Thereby, the coating layer is cured, and the surface irregularity shape of the mold irregularity surface is transferred to the coating layer surface. The mold used here is of a roll shape, and is manufactured by using a roll-shaped mold substrate in the mold manufacturing method already described.
For example, as shown in FIG. 9, this step is performed by a coating zone 83 (in the case of drying, a drying zone 84, and in the case of performing a pre-curing step described later, the active energy ray irradiation device 86 is further irradiated. Irradiating the laminated body having the coating layer that has passed through the pre-curing zone) with an active energy ray using an active energy ray irradiating device 86 such as an ultraviolet ray irradiating device disposed on the transparent support 81 side. Can be performed.
First, a roll-shaped mold 87 is pressed against the surface of the coating layer of the laminate that has undergone the curing process using a crimping device such as a nip roll 88, and in this state, the active energy ray irradiation device 86 is used to make the transparent The coating layer 82 is cured by irradiating active energy rays from the support 81 side. Here, “curing the coating layer” means that the active energy ray-curable resin contained in the coating layer receives the energy of the active energy ray to cause a curing reaction. The use of the nip roll is effective in preventing air bubbles from being mixed between the coating layer of the laminate and the mold. One or a plurality of active energy ray irradiation apparatuses can be used.
After irradiation with the active energy ray, the laminate is peeled from the mold 87 with the nip roll 89 on the outlet side as a fulcrum. In the obtained transparent support and the cured coating layer, the cured coating layer becomes an antiglare layer, and the antiglare film of the present invention is obtained. The obtained antiglare film is usually wound up by a film winding device 90. At this time, for the purpose of protecting the antiglare layer, it may be wound up while a protective film made of polyethylene terephthalate, polyethylene or the like is adhered to the surface of the antiglare layer through a pressure-sensitive adhesive layer having removability. In addition, although the metal mold | die used here demonstrated the case of the thing of roll shape, metal mold | dies other than roll shape can also be used. Moreover, you may perform additional active energy ray irradiation after peeling from a metal mold | die.
The active energy ray used in this step is appropriately selected from ultraviolet rays, electron beams, near ultraviolet rays, visible light, near infrared rays, infrared rays, X-rays and the like according to the type of the active energy ray curable resin contained in the coating liquid. Among these, ultraviolet rays and electron beams are preferable, and ultraviolet rays are particularly preferable because they are easy to handle and high energy is obtained (as described above, the UV embossing method is preferable).
As the ultraviolet light source, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, an electrodeless lamp, a metal halide lamp, a xenon arc lamp, or the like can be used. An ArF excimer laser, a KrF excimer laser, an excimer lamp, synchrotron radiation, or the like can also be used. Among these, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, an electrodeless lamp, a xenon arc lamp, and a metal halide lamp are preferably used.
As the electron beam, 50 to 1000 keV emitted from various electron beam accelerators such as Cockloft Walton type, Bande graph type, resonance transformation type, insulation core transformation type, linear type, dynamitron type, and high frequency type, preferably 100 An electron beam having an energy of ~ 300 keV can be mentioned.
When the active energy ray is ultraviolet, the integrated amount of light at UVA ultraviolet is preferably at 100 mJ / cm ² or more 3000 mJ / cm ² or less, more preferably at 200 mJ / cm ² or more 2000 mJ / cm ² or less. In addition, since the transparent support may absorb ultraviolet rays on the short wavelength side, irradiation is performed so that the integrated light quantity of ultraviolet rays UVV (395 to 445 nm) in the wavelength region including visible light is preferable for the purpose of suppressing the absorption. The amount may be adjusted. Integrated light intensity in such UVV is preferably at 100 mJ / cm ² or more 3000 mJ / cm ² or less, and more preferably 200 mJ / cm ² or more 2000 mJ / cm ² or less. When the integrated light quantity is less than 100 mJ / cm ² , the coating layer is not sufficiently cured, the hardness of the resulting antiglare layer becomes low, or the uncured resin adheres to the guide roll, etc., causing process contamination Tend to be. Moreover, when the integrated light quantity exceeds 3000 mJ / cm ² , the transparent support may shrink and cause wrinkles due to heat radiated from the ultraviolet irradiation device.
[P3] Pre-curing step In this step, prior to the curing step, both end regions in the width direction of the transparent support of the coating layer are irradiated with active energy rays to pre-cure both end regions. It is a process. FIG. 10 is a cross-sectional view schematically showing the preliminary curing step. In FIG. 10, an end region 82b in the width direction of the coating layer (direction orthogonal to the transport direction) is a region having a predetermined width from the end portion including the end portion of the coating layer.
In the preliminary curing step, the end region is cured in advance, thereby further improving the adhesion with the transparent support 81 in the end region, and part of the cured resin is peeled off in the step after the curing step. It can prevent falling and contaminating the process. The end region 82b can be a region from 5 mm to 50 mm from the end of the coating layer 82, for example.
The irradiation of the active energy ray to the end region of the coating layer is performed, for example, with reference to FIGS. 9 and 10, for example, the coating layer that has passed through the coating zone 83 (drying zone 84 when drying). This is performed by irradiating the transparent support 81 having 82 with active energy rays using an active energy ray irradiating device 85 such as an ultraviolet ray irradiating device installed in the vicinity of both ends on the coating layer 82 side. Can do. The active energy ray irradiation device 85 may be any device as long as it can irradiate the end region 82b of the coating layer 82 with active energy rays, and may be installed on the transparent support 81 side.
The type of active energy ray and the light source are the same as in the main curing step. When the active energy ray is ultraviolet, the integrated amount of light at UVA ultraviolet is preferably at 10 mJ / cm ² or more 400 mJ / cm ² or less, and more preferably 50 mJ / cm ² or more 400 mJ / cm ² or less. By irradiating so that it may become 50 mJ / cm < ² > or more, the deformation | transformation in this hardening process can be prevented more effectively. In addition, when it exceeds 400 mJ / cm < ² >, as a result of a hardening reaction progressing excessively, resin peeling may arise in the boundary of a hardening part and an unhardened part resulting from a film thickness difference or distortion of an internal stress.
[Use of the antiglare film of the present invention]
The antiglare film of the present invention obtained as described above is used for an image display device or the like, and is usually used by being bonded to a polarizing film as a viewing side protective film of a viewing side polarizing plate (that is, an image). Placed on the surface of the display device). In addition, as described above, when a polarizing film is used as the transparent support, an antiglare film integrated with a polarizing film is obtained. Therefore, such an antiglare film integrated with a polarizing film may be used for an image display device. it can. The image display device provided with the antiglare film of the present invention has sufficient antiglare properties at a wide viewing angle, and can well prevent both whitening and glare.

Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, “%” and “parts” representing the content or amount used are based on weight unless otherwise specified.
The evaluation method of the metal mold | die or anti-glare film in the following examples is as follows.
[1] Measurement of surface shape of antiglare film (power spectrum of elevation of surface irregularity)
Using a three-dimensional microscope PLμ2300 (manufactured by Sensofar), the elevation of the surface uneven shape of the antiglare layer of the antiglare film as a measurement sample was measured. In order to prevent the sample from warping, an optically transparent pressure-sensitive adhesive was used, and the surface opposite to the antiglare layer of the measurement sample was bonded to a glass substrate, and then subjected to measurement. During the measurement, the objective lens was measured at a magnification of 10 times. The horizontal resolutions Δx and Δy were both 1.66 μm and the measurement area was 1270 μm × 950 μm. Sampling 512 × 512 data (measured area 850 μm × 850 μm) from the center of the obtained measurement data, the elevation of the surface uneven shape (surface uneven shape of the antiglare layer) of the antiglare film is two-dimensional The function h (x, y) was obtained. Then, two-dimensional function h (x, y) of the discrete Fourier transform to two-dimensional function _{H _(f} x, f _y) was determined. Two-dimensional function H (f _{x, f} _y) of a two-dimensional function I (f _{x, f} _y) of the absolute value squared by the two-dimensional power spectrum to calculate the one-dimensional power is a function of the distance f from the origin A one-dimensional function I (f) of the spectrum was calculated. The elevation is measured for five surface irregularities for each sample, and the average value of the one-dimensional function I (f) of the one-dimensional power spectrum calculated from the data is obtained as the one-dimensional function I of the one-dimensional power spectrum of each sample. (F).
[2] Measurement of optical properties of antiglare film (haze)
The total haze of the antiglare film was bonded to the glass substrate by using an optically transparent adhesive for the antiglare film, pasting the surface opposite to the antiglare layer of the measurement sample to the glass substrate. About the anti-glare film, light was incident from the glass substrate side and measured by a method based on JIS K 7136 using a haze meter “HM-150” manufactured by Murakami Color Research Laboratory Co., Ltd. The surface haze was determined by determining the internal haze of the antiglare film and subtracting the internal haze from the total haze by the following formula: surface haze = total haze-internal haze. The internal haze was measured in the same manner as the total haze after a triacetyl cellulose film having a haze of approximately 0 was attached to the antiglare layer surface of the measurement sample after measuring the total haze with glycerin.
(Transparency definition)
By the method based on JIS K 7105, the transmission clarity of the anti-glare film was measured using the image clarity measuring device “ICM-1DP” manufactured by Suga Test Instruments Co., Ltd. Also in this case, in order to prevent the sample from warping, the surface opposite to the antiglare layer of the measurement sample was bonded to the glass substrate using an optically transparent adhesive, and then used for the measurement. In this state, light was incident from the glass substrate side and measurement was performed. The measured values here are values measured using five types of optical combs in which the widths of the dark part and the bright part are 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm, respectively. Is the sum of
(Reflection sharpness measured at 45 ° light incident angle)
By a method based on JIS K 7105, the reflection clarity of the antiglare film was measured using an image clarity measuring device “ICM-1DP” manufactured by Suga Test Instruments Co., Ltd. Also in this case, in order to prevent the sample from warping, the surface opposite to the antiglare layer of the measurement sample was bonded to the black acrylic substrate using an optically transparent adhesive, and then subjected to measurement. . In this state, light was incident at 45 ° from the antiglare layer surface side, and measurement was performed. The measured values here are the total values of the values measured using four types of optical combs in which the widths of the dark part and the bright part are 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm, respectively. is there.
(Reflection sharpness measured at 60 ° light incident angle)
By a method based on JIS K 7105, the reflection clarity of the antiglare film was measured using an image clarity measuring device “ICM-1DP” manufactured by Suga Test Instruments Co., Ltd. Also in this case, in order to prevent the sample from warping, the surface opposite to the antiglare layer of the measurement sample was bonded to the black acrylic substrate using an optically transparent adhesive, and then subjected to measurement. . In this state, light was incident at 60 ° from the antiglare layer surface side, and measurement was performed. The measured values here are the total values of the values measured using four types of optical combs in which the widths of the dark part and the bright part are 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm, respectively. is there.
(Reflectance ratio)
The antiglare layer of the antiglare film is irradiated with parallel light from a He-Ne laser having a wavelength of 543.5 nm from a direction inclined by 30 ° with respect to the normal line of the antiglare film, and the film normal line and the irradiation direction are changed. The change in the angle of the reflectance in the plane including it was measured. In the measurement of reflectance, both “32903 Optical Power Sensor” and “3292 Optical Power Meter” manufactured by Yokogawa Electric Corporation were used. Also in this case, in order to prevent the sample from warping, the surface opposite to the antiglare layer of the measurement sample was bonded to the black acrylic substrate using an optically transparent adhesive, and then subjected to measurement. .
[3] Evaluation of anti-glare performance of anti-glare film (visual evaluation of reflection and whitishness)
In order to prevent reflection from the back of the antiglare film, the antiglare film is bonded to a black acrylic resin plate on the surface opposite to the antiglare layer of the measurement sample. Visual observation was made from the layer side, and the degree of reflection of the fluorescent lamp and the degree of whitening were visually evaluated. Regarding reflection, the degree of reflection when the antiglare film was observed from the front and the degree of reflection when observed from an oblique angle of 30 ° were evaluated. Reflection and whitishness were evaluated according to the following criteria in three stages of 1 to 3, respectively.
Reflection 1: Reflection is not observed.
2: Reflection is slightly observed.
3: Reflection is clearly observed.
Whiteness 1: No whiteness is observed.
2: A little whitish is observed.
3: The whitish is clearly observed.
(Evaluation of glare)
Glare was evaluated according to the following procedure. That is, first, a photomask having a unit cell pattern as shown in a plan view in FIG. 11 was prepared. In this figure, a unit cell 100 has a key-shaped chrome light-shielding pattern 101 having a line width of 10 μm formed on a transparent substrate, and a portion where the chrome light-shielding pattern 101 is not formed is an opening 102. Here, a unit cell having a size of 211 μm × 70 μm (vertical × horizontal in the figure) and an opening having a dimension of 201 μm × 60 μm (vertical × horizontal in the figure) was used. A large number of unit cells shown in the figure are arranged vertically and horizontally to form a photomask.
Then, as shown in the schematic cross-sectional view of FIG. 12, the chrome light-shielding pattern 111 of the photomask 113 is placed on the light box 115 and the antiglare film 110 is attached to the glass plate 117 with an adhesive on the antiglare layer. The sample bonded to the surface is placed on the photomask 113. A light source 116 is disposed in the light box 115. In this state, by visually observing at a position 119 that is about 30 cm away from the sample, the degree of glare was sensory evaluated in seven stages. Level 1 corresponds to a state where no glare is observed, level 7 corresponds to a state where severe glare is observed, and level 4 refers to a state where only slight glare is observed.
(Contrast evaluation)
The polarizing plates on both the front and back surfaces were peeled off from a commercially available liquid crystal television (“KDL-32EX550” manufactured by Sony Corporation). Instead of these original polarizing plates, both the back side and the display side are polarizing plates "Sumikaran SRDB831E" manufactured by Sumitomo Chemical Co., Ltd. so that the respective absorption axes coincide with the absorption axes of the original polarizing plates. Further, the antiglare film shown in each of the following examples was laminated on the display surface side polarizing plate via an adhesive such that the concavo-convex surface was the surface. The liquid crystal television thus obtained was activated in a dark room, and the luminance in the black display state and the white display state was measured using a luminance meter “BM5A” manufactured by Topcon Corporation, and the contrast was calculated. Here, the contrast is represented by the ratio of the luminance in the white display state to the luminance in the black display state. The result showed the contrast measured in the state which bonded the anti-glare film in the ratio of the contrast measured in the state which does not bond an anti-glare film.
[4] Evaluation of pattern for production of anti-glare film The created pattern data was made into binary image data of two gradations, and the gradation was expressed by a two-dimensional discrete function g (x, y). The horizontal resolutions Δx and Δy of the discrete function g (x, y) are both 2 μm. The resulting two-dimensional function g (x, y) and by discrete Fourier transform, two-dimensional function _{G _(f} x, f _y) was determined. Two-dimensional function G (f _{x, f} _y) of a two-dimensional function gamma (f _{x, f} _y) of the absolute value squared by the two-dimensional power spectrum to calculate the one-dimensional power is a function of the distance f from the origin A one-dimensional function Γ (f) of the spectrum was calculated.
<Example 1>
(Production of molds for the production of anti-glare films)
An aluminum roll having a diameter of 300 mm (A6063 by JIS) having a copper ballad plating applied thereto was prepared. Copper ballad plating consists of a copper plating layer / thin silver plating layer / surface copper plating layer, and the thickness of the entire plating layer was set to be about 200 μm. The copper plating surface was mirror-polished, and a photosensitive resin was applied to the polished copper plating surface and dried to form a photosensitive resin film. Next, a pattern in which the pattern A shown in FIG. 13 was repeatedly arranged was exposed on a photosensitive resin film with a laser beam and developed. Laser beam exposure and development were performed using Laser Stream FX (manufactured by Sink Laboratories). As the photosensitive resin film, a film containing a positive photosensitive resin was used. Here, the pattern A is created by passing a plurality of Gaussian function type band pass filters from a pattern having a random brightness distribution, the aperture ratio is 45%, and the spatial frequency of the one-dimensional power spectrum is 0. .01μm intensity in the intensity gamma (0.01) and the spatial frequency 0.02 [mu] m ^-1 at ^-1 gamma ratio gamma (0.02) in (0.02) / Γ (0.01) is 0.09, the ratio of the intensity in the intensity gamma (0.01) and the spatial frequency 0.1 [mu] m ^-1 in the spatial frequency ^{0.01μm -1 Γ (0.1) Γ (} 0.1) / Γ (0.01) 8.13 It is.
Then, the etching process was performed with cupric chloride solution. The etching amount at that time was set to 4.5 μm. The photosensitive resin film was removed from the roll after the etching treatment, and chrome plating was performed to produce a mold A. At this time, the chromium plating thickness was set to 10 μm.
(Preparation of antiglare film)
Each of the following components was dissolved in ethyl acetate at a solid content concentration of 60%, and an ultraviolet curable resin composition A capable of forming a film having a refractive index of 1.53 after curing was prepared.
Pentaerythritol triacrylate 60 parts Multifunctional urethanated acrylate 40 parts (Reaction product of hexamethylene diisocyanate and pentaerythritol triacrylate)
5 parts of diphenyl (2,4,6-trimethoxybenzoyl) phosphine oxide On the triacetyl cellulose (TAC) film having a thickness of 60 μm, this UV curable resin composition A is dried to have a thickness of 5 μm. And dried in a dryer set at 60 ° C. for 3 minutes. The dried film was brought into close contact with the molding surface of the mold A obtained previously (the surface having an uneven surface shape) with a rubber roll so that the coating layer after drying was on the mold side. In this state, an anti-glare film is manufactured by irradiating light from a high-pressure mercury lamp with an intensity of 20 mW / cm ² from the TAC film side so that the amount of light converted to h-ray is 200 mJ / cm ² and curing the coating layer. did. Thereafter, the obtained antiglare film was peeled off from the mold to produce a transparent antiglare film A having an antiglare layer on the TAC film.
<Example 2>
Except that the chrome plating thickness in the chrome plating process was set to 9 μm, the mold B was prepared in the same manner as the mold A in Example 1, and the mold A was replaced with the mold B. An antiglare film was prepared in the same manner as in Example 1. This antiglare film is designated as an antiglare film B.
<Example 3>
Except that the chrome plating thickness in the chrome plating process was set to 11 μm, the mold C was prepared in the same manner as the mold A in Example 1, and the mold A was replaced with the mold C. An antiglare film was prepared in the same manner as in Example 1. This antiglare film is designated as an antiglare film C.
<Comparative Example 1>
Except that the chrome plating thickness in the chrome plating process was set to 7 μm, the mold D was manufactured in the same manner as the mold A in Example 1, and the mold A was replaced with the mold D. An antiglare film was prepared in the same manner as in Example 1. This antiglare film is designated as an antiglare film D.
<Comparative example 2>
A mold E was prepared in the same manner as the mold A in Example 1 except that a pattern in which the patterns B shown in FIG. 14 were repeatedly arranged was exposed on the photosensitive resin film with laser light. An antiglare film was produced in the same manner as in Example 1 except that the mold E was used. This antiglare film is designated as an antiglare film E. Here, the pattern B is created by passing a plurality of Gaussian function type bandpass filters from a pattern having a random brightness distribution, has an aperture ratio of 45.0%, and has a one-dimensional power spectrum space. the ratio Γ (0.02) / Γ (0.01 ) is 2.69 of the intensity in the intensity gamma (0.01) and the spatial frequency 0.02 [mu] m ^-1 in the frequency 0.01μm ^-1 Γ (0.02) There, the ratio gamma (0.1) of the intensity in the intensity gamma (0.01) and the spatial frequency 0.1 [mu] m ^-1 in the spatial frequency ^{0.01μm -1 Γ (0.1) / Γ} (0.01) 278 .67.
<Comparative Example 3>
The surface of a 300 mm diameter aluminum roll (JIS A5056) is mirror-polished, and the polished aluminum surface is coated with zirconia beads TZ-SX-17 (Tosoh Corp.) using a blasting device (Fuji Seisakusho). ), Average particle size: 20 μm), and blasted at a blast pressure of 0.1 MPa (gauge pressure, the same applies hereinafter) and a bead usage of 8 g / cm ² (a used amount per 1 cm ² of surface area of the roll, the same applies hereinafter) The roll surface was uneven. The obtained uneven aluminum roll was subjected to electroless nickel plating to produce a mold F. At this time, the electroless nickel plating thickness was set to 15 μm. An antiglare film was produced in the same manner as in Example 1 except that the mold A was replaced with the mold F. This antiglare film is designated as an antiglare film F.
<Comparative example 4>
A 200 mm diameter aluminum roll (A5056 according to JIS) was prepared by applying copper ballad plating to the surface. Copper ballad plating consists of a copper plating layer / thin silver plating layer / surface copper plating layer, and the thickness of the entire plating layer was about 200 μm. The copper plating surface is mirror-polished, and the blasting device (manufactured by Fuji Seisakusho Co., Ltd.) is used on the polished surface, and zirconia beads “TZ-SX-17” (manufactured by Tosoh Corp., average particle diameter: 20 μm) was blasted at a blast pressure of 0.05 MPa (gauge pressure, the same applies hereinafter) and a bead usage of 6 g / cm ² , and the aluminum roll surface was uneven. The resulting copper-plated aluminum roll with unevenness was subjected to chrome plating to produce a mold G. At this time, the chromium plating thickness was set to 6 μm. An antiglare film was produced in the same manner as in Example 1 except that the mold A was replaced with the mold G. This antiglare film is designated as an antiglare film G.
[Evaluation results]
Table 1 shows the results of evaluating the above antiglare films for the above Examples and Comparative Examples.

Although the antiglare films A to C (Examples 1 to 3) satisfying the requirements of the present invention have low haze, they have excellent antiglare properties regardless of whether the observation angle is front or oblique. In addition, the effect of suppressing whitishness and glare was sufficient. On the other hand, the antiglare film D (Comparative Example 1) was whitish. Anti-glare film E (Comparative Example 2) had insufficient anti-glare properties when observed obliquely. The antiglare film F (Comparative Example 3) was easily glaring. The antiglare film G (Comparative Example 4) had insufficient antiglare properties when observed from an oblique direction.

10 anti-glare film,
11 Light incident angle (30 °), 12 Reflected light to regular reflection angle (30 °),
40 Mold substrate,
41 The mold substrate surface (plating layer) that has undergone the first plating step and the polishing step,
46 1st surface uneven | corrugated shape formed by the etching process,
50 photosensitive resin film, 60 mask,
70 Surface with uneven surface shape after chrome plating,
71 chromium plating layer,
80 feed roll, 81 transparent support, 83 coating zone,
86 active energy ray irradiation device, 87 roll-shaped mold,
88, 89 Nip roll, 90 Film take-up device.

The antiglare film of the present invention is useful for an image display device such as a liquid crystal display.

Claims

An anti-glare film comprising a transparent support and an anti-glare layer having fine surface irregularities formed thereon,
The total haze of the antiglare film is 0.1% or more and 3% or less,
The surface haze is 0.1% or more and 2% or less,
For light incident at an incident angle of 30 °, the ratio R (40) / R (30) of the reflectance R (30) at the reflection angle of 30 ° and the reflectance R (40) at the reflection angle of 40 ° is 0. 00001 or more and 0.0025 or less,
The surface uneven shape has a power spectrum at an altitude of the following conditions (1) to (3):
(1) The intensity I (0.01) at a spatial frequency of 0.01 μm −1 is 2 μm 4 or more and 10 μm 4 or less;
(2) The intensity I (0.02) at a spatial frequency of 0.02 μm −1 is 0.1 μm 4 or more and 1.5 μm 4 or less; and (3) the intensity I at a spatial frequency of 0.1 μm −1 (0. 1. An antiglare film characterized in that both 1) are 0.0001 μm 4 or more and 0.01 μm 4 or less.
The sum Tc of transmission clarity measured using five types of optical combs in which the width of the dark part and the bright part is 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm is 375% or more. And
The sum Rc of reflection sharpness Rc (45) measured at an incident angle of 45 ° using four types of optical combs in which the width of the dark part and the bright part is 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm. ) Is 180% or less,
The sum Rc of reflection sharpness Rc (60) measured at a light incident angle of 60 ° using four types of optical combs having a dark part and a bright part width of 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm. ) Is 240% or less, the antiglare film according to claim 1.